WO2010104051A1 - Diffusion sheet, light control unit, and light source unit - Google Patents

Diffusion sheet, light control unit, and light source unit Download PDF

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Publication number
WO2010104051A1
WO2010104051A1 PCT/JP2010/053823 JP2010053823W WO2010104051A1 WO 2010104051 A1 WO2010104051 A1 WO 2010104051A1 JP 2010053823 W JP2010053823 W JP 2010053823W WO 2010104051 A1 WO2010104051 A1 WO 2010104051A1
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WO
WIPO (PCT)
Prior art keywords
sheet
diffusion
light source
light
value
Prior art date
Application number
PCT/JP2010/053823
Other languages
French (fr)
Japanese (ja)
Inventor
光太郎 小田
敬之 黒田
雅子 後藤
洋介 秦
直樹 谷口
Original Assignee
旭化成株式会社
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Publication date
Priority claimed from JP2009055635A external-priority patent/JP2010210828A/en
Application filed by 旭化成株式会社 filed Critical 旭化成株式会社
Publication of WO2010104051A1 publication Critical patent/WO2010104051A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0205—Diffusing elements; Afocal elements characterised by the diffusing properties
    • G02B5/0263—Diffusing elements; Afocal elements characterised by the diffusing properties with positional variation of the diffusing properties, e.g. gradient or patterned diffuser
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0037—Arrays characterized by the distribution or form of lenses
    • G02B3/0056—Arrays characterized by the distribution or form of lenses arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/04—Prisms
    • G02B5/045—Prism arrays
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133604—Direct backlight with lamps
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G02F1/133607—Direct backlight including a specially adapted diffusing, scattering or light controlling members the light controlling member including light directing or refracting elements, e.g. prisms or lenses

Definitions

  • the present invention relates to a diffusion sheet, a light beam control unit and a light source unit used for back lighting of a liquid crystal display device or the like.
  • liquid crystal display devices are used in a wide range of fields such as mobile phones, PDA terminals, digital cameras, televisions, personal computer displays, and notebook computers.
  • a light source unit such as a backlight unit is arranged behind a liquid crystal display panel, and an image is displayed by supplying light from the light source unit to the liquid crystal display panel.
  • the light source unit used in such a liquid crystal display device is required not only to supply uniform light to the liquid crystal display panel but also to supply as much light as possible in order to make the display image easy to see.
  • the light source unit is required to have optical characteristics such as excellent light diffusibility and high brightness.
  • the conventional light source unit for example, in order to make the distribution of the light incident on the liquid crystal display panel uniform over the entire panel, a method of giving an uneven shape to the light guide plate or the diffusion plate is used.
  • a method for imparting the shape there are a technique of injection molding of a resin using a mold, and a technique of processing a concavo-convex structure into a roll with a diamond blade and extrusion molding using the roll.
  • the mechanical unevenness forming method as described above has a problem that it takes a lot of time and the production cost is high. Further, the above-described unevenness forming method has a problem that the structure of about several tens of ⁇ m is the limit and it is not easy to improve the shape uniformity.
  • the concave / convex shape is recorded on the photosensitive medium by the speckle of the laser beam, a mold for pattern transfer is manufactured, and the surface of the light guide plate for the large liquid crystal display device of the direct type using this mold.
  • An invention is disclosed in which concavo-convex portions are formed on a holographic light guide plate (Patent Document 1, FIG. 41).
  • the present invention has been made in view of such a point, and an object thereof is to provide a diffusion sheet and a light beam control unit that can reduce luminance unevenness.
  • the diffusion sheet of the present invention is a diffusion sheet in which a diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface, and the predetermined direction
  • the peak value of the diffusion angle and the bottom value of the diffusion angle There is a plurality, and the arithmetic average value of the diffusion angles between the adjacent peak value and the bottom value is the arithmetic average value of the diffusion angles at all points distributed between the adjacent peak value and the bottom value. It is characterized by being larger.
  • the diffusion sheet of the present invention is a diffusion sheet in which a diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface, and the predetermined direction
  • a diffusion angle distribution diagram in which the horizontal axis represents the relative position within the sheet surface and the vertical axis represents the diffusion angle at the relative position within the sheet surface, a plurality of peak values are included in one high diffusion angle region. It is characterized by.
  • the diffusion angle distribution between adjacent peaks in the high diffusion angle region is linear.
  • the diffusion angle distribution between adjacent peaks in the high diffusion angle region is a downward convex curve shape or a mixed shape of a curve and a straight line.
  • the diffusion sheet of the present invention is a diffusion sheet in which a diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface, and the predetermined direction
  • a diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface, and the predetermined direction
  • the horizontal axis represents the relative position in the sheet surface and the vertical axis represents the diffusion angle at the relative position in the sheet surface
  • the diffusion angle distribution in the low diffusion angle region has a downward convex curve with the bottom value as a minimum value.
  • the diffusion sheet of the present invention periodically has a peak value of the diffusion angle and a bottom value of the diffusion angle alternately, and an arithmetic average value of the diffusion angles at two points of the adjacent peak value and the bottom value. Is larger than the arithmetic average value of the diffusion angles at all points distributed between the adjacent peak value and the bottom value, and the distribution of the diffusion angles includes the peak value and has an upward convex curve shape. It is preferable to have one section and a second section in which the distribution of the diffusion angle includes the bottom value and has a downward convex curve shape.
  • the diffusion angle of the diffused light in the entire region is in the range of 0.1 ° to 120 ° in the diffusion angle distribution diagram.
  • the minimum value of the diffusion angle in the diffusion angle distribution diagram is 0.1 ° to 40 °.
  • the difference between the maximum value and the minimum value of the diffusion angle is preferably 40 ° or more and 80 ° or less.
  • the previous diffusion angle is generated by an uneven structure formed on the surface of the diffusion sheet.
  • the diffusion sheet of the present invention is a diffusion sheet in which the aspect ratio of the concavo-convex structure provided on the sheet surface changes periodically along a predetermined direction in the sheet surface, and the in-sheet surface in the predetermined direction
  • the aspect ratio distribution diagram in which the relative position of the aspect ratio is taken on the horizontal axis and the aspect ratio at the relative position in the sheet surface is taken on the vertical axis, there are a plurality of peak values of the aspect ratio and bottom values of the aspect ratio.
  • the arithmetic average value of the aspect ratio between the matching peak value and the bottom value is larger than the arithmetic average value of the aspect ratio at all points distributed between the adjacent peak value and the bottom value.
  • the diffusion sheet of the present invention is a diffusion sheet in which the aspect ratio of the concavo-convex structure provided on the sheet surface changes periodically along a predetermined direction in the sheet surface, and the in-sheet surface in the predetermined direction
  • the aspect ratio distribution diagram in which the horizontal axis is the horizontal axis and the vertical axis is the aspect ratio at the relative position in the sheet surface, a plurality of peak values are included in one high aspect ratio region.
  • the aspect ratio distribution between adjacent peaks in the high aspect ratio region is preferably linear.
  • the aspect ratio distribution between adjacent peaks in the high aspect ratio region is a downwardly convex curve shape or a mixed shape of a curve and a straight line.
  • the diffusion sheet of the present invention is a diffusion sheet in which the aspect ratio of the concavo-convex structure provided on the sheet surface changes periodically along a predetermined direction in the sheet surface, and the in-sheet surface in the predetermined direction
  • the horizontal axis is the horizontal axis and the aspect ratio at the relative position in the sheet plane is the vertical axis
  • the aspect ratio distribution has a downward convex curve with the bottom value as a minimum value.
  • the diffusion sheet of the present invention has the peak value of the aspect ratio distribution and the bottom value of the aspect ratio distribution alternately and periodically, and the aspect ratio distribution at two points of the adjacent peak value and the bottom value.
  • the arithmetic average value is larger than the arithmetic average value of the aspect ratio distribution at all points distributed between the adjacent peak value and the bottom value, and the aspect ratio distribution includes the peak value and has an upwardly convex curve shape
  • the first section has a second section in which the aspect ratio distribution includes the bottom value and has a downward convex curve shape.
  • the diffusion sheet of the present invention preferably has a shape in which the aspect ratio changes as the height of the concavo-convex structure changes.
  • the diffusion sheet of the present invention preferably has a shape in which the aspect ratio changes as the pitch of the uneven structure changes.
  • the uneven structure is preferably an uneven structure formed using a speckle pattern by interference exposure.
  • the light source unit of the present invention preferably includes two or more light sources and the diffusion sheet disposed above the light sources.
  • the light source unit of the present invention includes at least two light sources, a reflection sheet that is disposed below the light source and reflects light from the light source, and the diffusion sheet that is disposed above the light source. It is preferable.
  • the light source unit of the present invention includes at least two light sources, a reflection sheet that is disposed below the light source and reflects light from the light source, and is disposed above the light source and diffuses light from the light source. It is preferable that the diffusion plate to be disposed and the diffusion sheet disposed above the diffusion plate.
  • the light source is preferably a linear light source.
  • the light source is preferably a point light source.
  • the period of the diffusion angle distribution of the diffusion sheet and the period of the illuminance distribution on the light incident surface of the diffusion sheet are substantially equal.
  • the light source unit of the present invention preferably includes a diffusion plate disposed between the diffusion sheet and the light source and containing a diffusing agent therein, and a reflection sheet disposed below the light source.
  • the light source unit of the present invention it is preferable to include a lens sheet disposed above the diffusion sheet.
  • the light source unit according to the present invention preferably includes a prism sheet disposed above the diffusion sheet.
  • the light source unit of the present invention preferably includes a reflective polarizing sheet disposed above the diffusion sheet.
  • the light source unit of the present invention preferably has an optical sheet having a lens portion formed of a plurality of lenses on the surface, and the diffusion sheet is disposed on the surface side of the optical sheet.
  • the lens portion of the optical sheet is configured by arranging a plurality of unit lenses, and the bottom shape of the unit lens is an anisotropic shape.
  • the bottom shape of the unit lens is an ellipse or a rectangle.
  • the unit lens is preferably a lenticular lens or a prism array.
  • the lens portion of the optical sheet is formed by arranging a plurality of unit lenses, and that the shape of the bottom surface of the unit lens is isotropic.
  • the bottom shape of the unit lens is a circle, a square, or a regular hexagon.
  • the unit lens is preferably a microlens or a microprism.
  • the lens portion of the optical sheet may be configured by arranging a lens having a shape whose bottom surface has anisotropy and a lens having an isotropic shape. preferable.
  • the liquid crystal display device of the present invention preferably includes a liquid crystal display panel and the light source unit described above that supplies light to the liquid crystal display panel.
  • the light beam control unit of the present invention has a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface, and is configured by a plurality of lenses on the surface.
  • the light beam control unit of the present invention has a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface, and is configured by a plurality of lenses on the surface.
  • An optical sheet having a lens portion and an aspect ratio of the concavo-convex structure provided on the sheet surface along a predetermined direction in the sheet surface when a light beam is incident on the sheet surface of the optical sheet perpendicularly.
  • a diffusion sheet that changes periodically.
  • the diffusion sheet is disposed on the surface side of the optical sheet.
  • the lens portion of the optical sheet is preferably configured by arranging a plurality of unit lenses, and the bottom shape of the unit lens is preferably an anisotropic shape. .
  • the bottom shape of the unit lens is an ellipse or a rectangle.
  • the unit lens is preferably a lenticular lens or a prism array.
  • the lens portion of the optical sheet is preferably configured by arranging a plurality of unit lenses, and the bottom shape of the unit lens is preferably isotropic. .
  • the bottom shape of the unit lens is a circle, a square, or a regular hexagon.
  • the unit lens is preferably a microlens or a microprism.
  • the lens portion of the optical sheet is configured by arranging a lens having a shape whose bottom surface has anisotropy and a lens having an isotropic shape. Is preferred.
  • the diffusion angle of the diffusion sheet is in the range of 0.1 ° to 120 °.
  • the diffusion angle is generated by an uneven structure formed on the surface of the diffusion sheet.
  • the concavo-convex structure is formed using a speckle pattern by interference exposure.
  • the light source unit of the present invention includes two or more light sources and the light beam control unit disposed above the light sources.
  • the period of the diffusion angle distribution of the diffusion sheet is substantially equal to the period of the illuminance distribution on the light incident surface of the diffusion sheet.
  • the light source unit of the present invention it is preferable to include a reflective sheet disposed below the light source.
  • the light source unit according to the present invention preferably includes a prism sheet disposed above the diffusion sheet.
  • the light source unit of the present invention preferably includes a reflective polarizing sheet disposed above the diffusion sheet.
  • the liquid crystal display device of the present invention includes a liquid crystal display panel and the light source unit that supplies light to the liquid crystal display panel.
  • the diffusion sheet of the present invention it is possible to realize a diffusion sheet that can reduce uneven brightness.
  • the light control unit has a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface, and is configured by a plurality of lenses on the surface.
  • the diffusion sheet is disposed on the surface side of the optical sheet on which the lens is formed, so that light is emitted to a region between the light sources by the synergistic effect of diffusibility of the two sheets.
  • (A), (b) is a figure which shows the projection area
  • (A)-(f) is a figure which shows distribution with respect to the relative position in a sheet
  • (A)-(f) is a figure which shows distribution with respect to the relative position in the sheet surface of the aspect-ratio of the diffusion sheet which concerns on Embodiment 1 of this invention.
  • FIG. (A)-(f) is a figure which shows distribution with respect to the relative position in a sheet
  • FIG. (A)-(f) is a figure which shows distribution with respect to the relative position in a sheet
  • FIG. It is a figure which shows the structure of the light beam control unit which concerns on Embodiment 2 of this invention. It is a figure which shows the cross-section of the light beam control unit which concerns on Embodiment 2 of this invention.
  • (A)-(f) is a schematic diagram when the optical sheet used for the light beam control unit concerning Embodiment 2 of this invention is seen from the front.
  • (A)-(c) is a schematic diagram at the time of seeing the optical sheet used for the light beam control unit concerning Embodiment 2 of this invention from diagonally upward.
  • (A)-(e) is a schematic diagram when the optical sheet used for the light beam control unit according to Embodiment 2 of the present invention is viewed from the front.
  • (A)-(e) is a schematic diagram when the optical sheet used for the light beam control unit according to the second embodiment of the present invention is viewed obliquely from above.
  • (A)-(e) is a schematic diagram when the optical sheet used for the light beam control unit according to Embodiment 2 of the present invention is viewed from the front.
  • (A), (b) is a figure which shows the structure of the light source unit which concerns on Embodiment 3 of this invention.
  • (A), (b) is a figure which shows the structure of the light source unit which concerns on Embodiment 3 of this invention.
  • (A), (b) is a figure which shows the structure of the light source unit which concerns on Embodiment 3 of this invention. It is a figure which shows distribution with respect to the relative position in a sheet
  • (A)-(c) is a figure which shows the other example of a structure of the light source unit which concerns on Embodiment 3 of this invention. It is a figure which shows the other example of a structure of the light source unit which concerns on Embodiment 3 of this invention.
  • (A)-(d) is a figure which shows the other example of a structure of the light source unit which concerns on Embodiment 3 of this invention.
  • (A), (b) is a figure which shows the other example of a structure of the light source unit which concerns on Embodiment 3 of this invention.
  • (A), (b) is a figure which shows the cross-section of the light source unit which concerns on Embodiment 3 of this invention.
  • (A)-(c) is a figure which shows the relationship between the diffusion angle of a diffusion sheet, and light source distance in the Example of this invention.
  • (A), (b) is a figure which shows the relationship between the diffusion angle of a diffusion sheet, and light source distance in the Example of this invention.
  • (A)-(c) shows arrangement
  • (A)-(c) is a figure which shows the relationship between the diffusion angle of a diffusion sheet, and light source distance in the Example of this invention.
  • Embodiment 1 In Embodiment 1, an example of the diffusion sheet of the present invention will be described.
  • FIGS. 2A and 2B show the projection area between the light source and the projection area between the light sources.
  • a plurality (at least two) of light sources are arranged.
  • a line light source such as a cold cathode fluorescent lamp (CCFL) 101 as shown in FIG. 2A, or a point light source such as an LED (light emitting diode) 102 or a laser as shown in FIG. 2B.
  • CCFL cold cathode fluorescent lamp
  • FIGS. 2A and 2B show an example in which the entire area is divided into a projection area immediately above the light source and a projection area between the light sources. Further, it may be divided so as to provide an area other than the projection area between the light sources.
  • the projection area between the light sources may not be adjacent to the projection area immediately above the light source, and may include an area located in the middle of the adjacent light sources.
  • the diffusion sheet shown in the first embodiment is characterized in that the diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface.
  • this sheet is disposed above the light source, it is preferable to adjust the period of the diffusion angle of the sheet to the projection area period composed of the region directly above the light source and the region between the light sources. Thereby, luminance unevenness can be reduced.
  • the “diffusion angle” refers to an angle (FWHM: Full Width Half Maximum) that is twice the angle (half-value angle) at which the transmitted light intensity attenuates to half of the peak intensity (see FIG. 8A).
  • This diffusion angle can be obtained, for example, by measuring the angular distribution of transmitted light intensity with respect to light incident from the uneven surface side from the normal direction of the uneven surface of the diffusion sheet, with Photon manufactured by Photon Co., Ltd. it can.
  • the normal direction of the diffusion sheet refers to the direction shown in FIG.
  • both an isotropic diffusion sheet capable of obtaining substantially the same diffusion angle regardless of the measurement direction and an anisotropic diffusion sheet having a different diffusion angle depending on the measurement direction can be used.
  • An anisotropic diffusion sheet is, for example, a diffusion sheet having different diffusion angles when the diffusion angles are measured in two orthogonal directions.
  • FIG. 1 is a diagram showing a distribution of diffusion angles (or aspect ratios) in the diffusion sheet shown in the first embodiment.
  • the diffusion angle (or aspect ratio) of emitted light when a light beam is incident on the sheet surface perpendicularly changes periodically along a predetermined direction in the sheet surface.
  • the horizontal axis indicates the relative position within the sheet surface in a predetermined direction within the sheet surface, and the diffusion angle (or aspect at the relative position within the sheet surface). Ratio) on the vertical axis.
  • the diffusion sheet according to Embodiment 1 has a plurality of diffusion angle (or aspect ratio) peak values and diffusion angle (or aspect ratio) bottom values (one is shown in FIG. 1).
  • the peak value refers to the value of the highest diffusion angle (or aspect ratio) in one period of the distribution of the diffusion angle (or aspect ratio), and the bottom value refers to 1 of the distribution of the diffusion angle (or aspect ratio).
  • the value of the lowest diffusion angle (or aspect ratio) in the period refers to the value of the highest diffusion angle (or aspect ratio) in one period of the distribution of the diffusion angle (or aspect ratio)
  • the bottom value refers to 1 of the distribution of the diffusion angle (or aspect ratio).
  • the arithmetic average value of the diffusion angles between adjacent peak values and bottom values is between the adjacent peak values and bottom values. It is characterized by being larger than the arithmetic average value of the diffusion angles at all the distributed points.
  • the “all points” described here mean all the measurement points.
  • Changes in the diffusion angle are strictly linear, curved if the arithmetic average value of the adjacent peak value and the bottom value is greater than the arithmetic average value of the diffusion angle distributed between the adjacent peak value and the bottom value,
  • the shape may not be stepped, and may be a straight shape, a curved shape, a shape slightly deviated from the stepped shape, or a mixed shape of a straight line and a curved line due to variation in measurement of the diffusion angle.
  • the light incident angle with respect to that position increases linearly.
  • FIGS. 3A to 3F show examples of the diffusion sheet in which the diffusion angle is changed to a linear shape, a curved shape, or a mixed shape of a straight line and a curved line.
  • a region having a relatively high diffusion angle may be disposed immediately above the light source, and a region having a relatively low diffusion angle may be disposed directly above the light source.
  • region changes smoothly.
  • a shape including a plurality of continuous peak values in the high diffusion angle region is preferable from the viewpoint of reducing luminance unevenness, and the shape is a straight line or a downwardly convex curve, or a mixture of a straight line and a downwardly convex curve.
  • the shape is preferable (FIGS. 3D and 3F). Such a pattern is particularly effective when the light source is a linear light source.
  • FIG. 3C shows a first section in which the distribution of the diffusion angle includes the peak value and has a convex curve shape, and a second section in which the distribution of the diffusion angle includes the bottom value and has a convex curve shape.
  • the high diffusion angle region is an angle region that is equal to or greater than the arithmetic average value of the maximum value of the peak value and the minimum value of the bottom value
  • the low diffusion angle region is the value of the maximum value of the peak value and the minimum value of the bottom value.
  • the angle region is less than the arithmetic average value.
  • the arithmetic average value is calculated from the peak value and the bottom value in the present invention using the distribution of diffusion angles based on the above definition.
  • the peak value and the bottom value are not limited to one, and a plurality of the same values may exist. For example, in FIG. 1, there are a plurality (two) of peak values in one high diffusion angle region.
  • the diffusion angle distributed between adjacent peak values and bottom values refers to the diffusion angle existing in the broken line section of FIG. That is, when there are a plurality of peak values, it means the diffusion angle existing in the section between the position corresponding to the adjacent bottom value and the position corresponding to the peak value.
  • “periodically” means that the repeated patterns are compared with each other, and the peak value corresponding to the same repetition and the displacement from the start point of the period giving the peak value, and the bottom value and the bottom value are given. If the displacement from the starting point of the cycle is within a range of ⁇ 15% (preferably within 10%, more preferably within 5%) of the average value of all the repeated patterns, it periodically changes. Shall.
  • the direction indicating the periodicity may be at least one in the diffusion sheet surface, and can be specified by creating a distribution of diffusion angles on the diffusion sheet surface.
  • the diffusion angle of a plurality of repeated peak values is preferably such that the difference in the diffusion angles of all measured peak values is within 5 °, more preferably within 3 °, and within 2 °. Most preferably it is. The same applies to the bottom value.
  • FIGS. 5 to 7 are diagrams showing examples of arrangement of the high diffusion angle (high aspect ratio) region and the low diffusion angle (low aspect ratio) region of the diffusion sheet of the present invention.
  • 5 and 6 show that a high diffusion angle (high aspect ratio) region 201 and a low diffusion angle (low aspect ratio) region 202 periodically exist in the x-axis direction within the diffusion sheet surface, that is, a diffusion angle ( (Aspect ratio) changes periodically as shown in FIGS.
  • a pattern is preferably used for a line light source, but is also used for a point light source in some cases.
  • FIG. 7 is a diagram in which a high diffusion angle (high aspect ratio) region 203 and a low diffusion angle (low aspect ratio) region 204 periodically exist in the x-axis direction and the y-axis direction in the sheet surface.
  • the diffusion angle (aspect ratio) changes as shown in FIGS. 3 and 4 in the cross section in the x-axis or y-axis direction of the diffusion sheet.
  • Such a pattern is preferably used for a point light source, but may be used for a line light source.
  • the diffusion angle of the diffused light emitted from the diffusion sheet is preferably in the range of 0.1 ° or more and 120 ° or less in consideration of reducing luminance unevenness in the entire area in the plane. .
  • the diffusion angle is preferably controlled in the range of 0.1 ° to 100 °, and more preferably in the range of 0.1 ° to 80 °, in order to obtain high front luminance. preferable.
  • the diffusion angle is formed so as to be in the range of 0.1 ° to 80 °, and the diffusion angle difference is A large value is preferable from the viewpoint of eliminating uneven brightness and improving brightness.
  • the minimum value of the diffusion angle is preferably controlled in the range of 0.1 ° to 40 °. From the viewpoint of eliminating luminance unevenness, the minimum value of the diffusion angle is more preferably controlled in the range of 0.1 ° to 30 °, and most preferably in the range of 0.1 ° to 20 °. However, in the part that does not affect the optical characteristics, for example, the end part that does not require the optical function when the product is used, or the minute area that does not affect the optical characteristics, the diffusion angle is It may be out of range.
  • the difference between the maximum value and the minimum value of the diffusion angle in the plane of the diffusion sheet is 40 ° or more and 80 ° or less.
  • the diffusion angle difference is set to 80 ° or less, and the amount of change in the diffusion characteristics with respect to the change in the position in the sheet surface is suppressed, the diffusion angle distribution can be finely controlled, thereby eliminating uneven brightness. Increases effectiveness.
  • the difference in diffusion characteristics can be set within a preferable range, and a light source unit with less luminance unevenness can be obtained.
  • it is preferably used because it exhibits high luminance unevenness elimination performance when the liquid crystal display device is thinned and the number of light sources is reduced.
  • Such a diffusion angle can be realized by having a large number of uneven structures on the surface of the diffusion sheet.
  • the uneven structure is, for example, a structure in which a large number of protrusions are provided on the surface.
  • the shape of the protrusions may be approximately conical, approximately spherical, approximately ellipsoidal, approximately lenticular lens, or approximately parabolic, and the protrusions may be regularly or irregularly arranged. It may be.
  • the protrusions may be connected by a continuous curved surface.
  • a pseudo random structure in which irregular irregularities are connected by a continuous curved surface can also be preferably used. This pseudo-random structure is preferably a fine three-dimensional structure characterized by non-planar speckles.
  • the three-dimensional structure characterized by non-planar speckles is suitable for forming a fine concavo-convex structure of 10 ⁇ m or less, which was difficult by machining.
  • the method of forming irregularities using non-planar speckle is a manufacturing method suitable for changing the diffusion angle in accordance with the region on the diffusion sheet.
  • an isotropic shape such as a microlens and an anisotropic shape such as a lenticular lens can be easily formed.
  • This concavo-convex structure is preferably irregular in height and pitch from the viewpoint of suppressing moire.
  • the diffusion sheet of the present invention only needs to have a part that has the function of diffusing light by arranging the uneven shapes as described above somewhere in the plane, and there is a part where the sheet surface is smooth. Also good.
  • the aspect ratio of the concavo-convex structure is greatly related to suppression of uneven brightness.
  • the aspect ratio is a value obtained by dividing the height of the concavo-convex structure by the pitch.
  • the pitch means the distance from the top of a certain uneven structure to the top of the adjacent uneven structure. That is, the height and pitch of the concavo-convex structure are greatly related to suppressing luminance unevenness.
  • the aspect ratio in the aspect ratio distribution diagram in which the horizontal axis represents the relative position in the sheet surface in a predetermined direction within the sheet surface and the vertical axis represents the aspect ratio at the relative position in the sheet surface, the aspect ratio There are a plurality of peak values and a bottom value of the aspect ratio, and an arithmetic average value of diffusion angles between the adjacent peak values and the bottom value is between the adjacent peak value and the bottom value. It is characterized by being larger than the arithmetic average value of the aspect ratio at all the distributed points.
  • the “all points” described here mean all the measurement points.
  • the change in the aspect ratio is strictly linear, curved, if the arithmetic average value of the adjacent peak value and the bottom value is larger than the arithmetic average value of the aspect ratio distributed between the adjacent peak value and the bottom value,
  • the shape may not be stepped, and may be a straight shape, a curved shape, a shape slightly deviated from the stepped shape, or a mixed shape of a straight line and a curved line due to variation in aspect ratio measurement.
  • FIGS. 4 (a) to 4 (f) show examples of diffusion sheets in which the aspect ratio is changed to a linear shape, a curved shape, or a mixed shape of a straight line and a curved line.
  • a region having a relatively high aspect ratio may be disposed immediately above the light source, or a region having a relatively low aspect ratio may be disposed directly above the light source.
  • the uneven height between the regions changes smoothly.
  • a shape including a plurality of peak values continuous in a high aspect ratio region is preferable from the viewpoint of reducing luminance unevenness, and the shape is a linear shape or a downwardly convex curve shape or a mixed shape of a straight line and a downwardly convex curve. It is preferable (FIGS. 4D and 4F).
  • Such a pattern is particularly effective when the light source is a linear light source.
  • the aspect ratio distribution in the low aspect ratio region including the bottom value is preferably a downward convex curve with the bottom value being a minimum value from the viewpoint of reducing luminance unevenness.
  • FIG. 4C shows a first section in which the aspect ratio distribution includes the peak value and has a convex curve shape, and a second section in which the aspect ratio distribution includes the bottom value and has a convex curve shape.
  • the high aspect ratio area is an area showing an aspect ratio that is equal to or higher than the arithmetic average value of the maximum peak value and the minimum bottom value
  • the low aspect area is the minimum peak value and the minimum bottom value.
  • the area indicates an aspect ratio that is less than or equal to the arithmetic average value.
  • the arithmetic average value of the aspect ratio distributed between the peak value and the bottom value in the present invention is calculated using the aspect ratio distribution based on the above definition. For example, in FIG. 1, a plurality of (two) peak values exist in one high aspect ratio region.
  • the aspect ratio distributed between adjacent peak values and bottom values refers to the aspect ratio existing in the broken line section of FIG. That is, when there are a plurality of peak values, the aspect ratio exists in the section between the position corresponding to the adjacent bottom value and the position corresponding to the peak value.
  • the shape in which the height of the concavo-convex structure changes while maintaining the value of the aspect ratio can be performed without changing the optical system, so that it is inexpensive and easy to manufacture a diffusion sheet. It is preferable from the viewpoint.
  • FIG. 9 shows a schematic diagram of an example of a shape when the diffusion sheet of the present invention is cut in a cross section perpendicular to the horizontal plane and parallel to a certain direction in the plane.
  • the horizontal distance w from end to end in the cross section of each recess or projection is defined as the pitch in the direction of the recess or projection, and the maximum depth or height l in the range of the horizontal distance w is the recess or The depth or height in the direction of the convex portion.
  • the aspect ratio can be determined by dividing the depth or height l by the width w.
  • the aspect ratio values used in the present invention each include a measurement point, and a concave or convex portion existing in a range of 100 ⁇ m centering on the measurement point in a cross section perpendicular to the diffusion sheet surface and parallel to a predetermined direction.
  • the average value may be obtained by extracting at least 15 concave portions or convex portions from the corresponding area.
  • the uneven structure on the surface can be observed by, for example, a scanning electron microscope image of a cross section of the diffusion sheet or a laser confocal microscope.
  • the diffusion sheet of the present invention it is only necessary to have a portion where the uneven shape is arranged somewhere in the plane and exhibit a function of diffusing light, and there may be a portion where the sheet surface is smooth. In this case, the aspect ratio is zero.
  • the aspect ratio in the entire region is preferably in the range of 0 to 4 from the viewpoint of the effect of reducing luminance unevenness. Further, from the viewpoint of exhibiting the effect of controlling the diffusion of light, it is more preferably 0 to 3, and further preferably 0 to 2.
  • the aspect ratio of the unevenness in the part that does not affect the optical characteristics for example, the extreme end part that does not require the optical function when it is made as a product, or the minute area that does not affect the optical characteristics is You may deviate from this range.
  • the aspect ratio of a plurality of repeated peak values is preferably such that the difference in aspect values of all measured peak values is within 0.2, more preferably within 0.15, Within 0.1 is most preferred. The same applies to the bottom value.
  • the definition of the periodic change of the aspect ratio conforms to the definition of the periodic change of the diffusion angle described above.
  • a diffusion sheet having this uneven structure on the surface and changing the diffusion angle depending on the region on the diffusion sheet can be specifically manufactured as follows. First, a sub-master type in which a speckle pattern is formed so that the diffusion angle changes depending on the position by irradiating a photosensitive material or a photoresist with a laser beam through a lens or a mask in advance by interference exposure. By changing the distance and size between the members constituting the laser irradiation system and adjusting the size, shape and direction of the speckle pattern, the range of the diffusion angle can be controlled and the concavo-convex structure having different diffusion angles can be recorded. .
  • the range of the diffusion angle depends on the average size and shape of the speckle. If speckle is small, the angle range is wide. Moreover, the unit structure of the unevenness is not limited to an isotropic one, and an anisotropic one can be formed, or an uneven structure in which both are combined can be formed. If the speckle is an oval in the horizontal direction, the shape of the angular distribution is an oval in the vertical direction. In this way, a sub-master type in which the diffusion angle changes depending on the position is manufactured. A metal is deposited on the sub-master mold by a method such as electroforming, and a speckle pattern is transferred to the metal to produce a master mold.
  • a speckle pattern is transferred to the light extraction surface of the light-transmitting resin layer by forming the light-transmitting resin layer with ultraviolet rays using the master mold.
  • a detailed manufacturing method of this diffusion sheet in which the diffusion angle is changed depending on the position is disclosed in JP-T-2003-525472 (International Publication No. 01/065469).
  • a light source a mask provided with a size and shape variable opening provided in an optical path of light projected from the light source, a plate for recording a diffusion pattern generated by the light projected from the light source, Using a diffuser plate that diffuses light disposed between the mask and the plate, and a blocker provided between the diffuser plate and the plate to block part of the light, the size and shape of the mask opening and blocker, It is made by changing the diffusion degree of the diffusion plate and the distance between the constituent members.
  • the shape of the bottom surface of the convex portion recorded on the plate is made into a horizontally long ellipse, and a region having a vertically long elliptical diffusivity (diffusing angles in two orthogonal directions are different) is formed.
  • a region having a vertically long elliptical diffusivity diffusing angles in two orthogonal directions are different.
  • the mask opening shape square the shape of the bottom surface of the convex portion recorded on the plate is isotropic, and a region showing isotropic diffusion ability (the diffusion angle is the same in all directions) is formed.
  • the diffusion sheet of the present invention that is, the diffusion sheet in which the diffusion angle or the ratio of the aspect ratio of the concavo-convex shape on the surface changes periodically is manufactured. it can.
  • the unevenness height of the surface structure can be determined from, for example, the pitch, aspect ratio, surface roughness, etc. of the cross-sectional shape of the diffusion sheet observed with a scanning electron microscope. Further, the pitch, aspect ratio, surface roughness, and the like can also be read from an observation image of the diffusion sheet surface by a laser confocal microscope. For example, as the pitch is shorter, the aspect ratio is larger, or the surface roughness is larger, it can be considered that the unevenness height is higher.
  • the uneven structure in the diffusion sheet of the present invention may be on the light exit surface side or the light entrance surface side of the sheet.
  • the concavo-convex structure on the light exit surface side is preferable from the viewpoint that the luminance unevenness can be reduced while minimizing the decrease in luminance.
  • the concavo-convex structure is on the light incident surface from the viewpoint of easy alignment in the surface of the light source and the diffusion sheet.
  • the surface opposite to the surface having the uneven structure may be a smooth surface, an uneven surface, a mat surface, or the like. From the viewpoint of improving the luminance and reducing the luminance unevenness, it is preferable that the surface opposite to the surface having the concavo-convex structure is a smooth surface. In general, when a diffusion sheet is laminated, a very small amount of beads may be applied to the surface opposite to the surface having the concavo-convex structure as long as smoothness is not lost in order to prevent damage. Such a case is also included in the smooth surface.
  • Embodiment 2 In Embodiment 2, an example of the light beam control unit of the present invention will be described.
  • the light source has a configuration in which a diffusion sheet whose diffusion angle is periodically changed in the sheet surface and an optical sheet having a lens formed on the surface thereof are disposed. It is possible to meet demands for eliminating high luminance unevenness, such as thinning the unit and reducing the number of light sources. In particular, when aiming at thinning the liquid crystal display device and reducing the number of light sources, the light beam control unit having the configuration in which the diffusion sheet is disposed on the lens forming surface side of the optical sheet exhibits high luminance unevenness elimination performance. Are preferably used.
  • a high diffusion angle (high aspect ratio) region 201 and a low diffusion angle (low aspect ratio) region 202 are arranged in the x-axis direction in the diffusion sheet plane. It can be configured to exist periodically, that is, the diffusion angle (aspect ratio) changes periodically (see FIGS. 5 and 6). Further, the high diffusion angle (high aspect ratio) region 203 and the low diffusion angle (low aspect ratio) region 204 periodically exist in the x-axis direction and the y-axis direction in the sheet surface, that is, the diffusion angle ( The aspect ratio may be changed periodically (see FIG. 7). As an example of the diffusion sheet constituting the light beam control unit, the diffusion sheet shown in the first embodiment can also be applied.
  • the light beam control unit shown in the second embodiment is applied to a line light source such as a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), a hot cathode fluorescent lamp (HCFL), or a point light source such as a light emitting diode (LED).
  • a line light source such as a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), a hot cathode fluorescent lamp (HCFL), or a point light source such as a light emitting diode (LED).
  • a line light source such as a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), a hot cathode fluorescent lamp (HCFL), or a point light source such as a light emitting diode (LED).
  • CCFL cold cathode fluorescent lamp
  • EEFL external electrode fluorescent lamp
  • HCFL hot cathode fluorescent lamp
  • LED light emitting diode
  • FIG. 12 is a schematic diagram when the light beam control unit shown in the second embodiment is viewed from obliquely above, and the lens formation of the lens-shaped optical sheet 14 in which a lens portion composed of a plurality of lenses is formed on the surface.
  • the diffusion sheet 15 is disposed on the surface side.
  • FIG. 13 is a schematic diagram of a cross-sectional structure of the light beam control unit in the cut surface of FIG. When used as a light beam control unit, it is preferable that the lens-forming surface side be the light exit surface from the viewpoint of eliminating uneven brightness and improving brightness.
  • the optical sheet on which the lens portion is formed has a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface.
  • the surface side on which the lens portion is not formed may be a smooth surface, an uneven surface, a mat surface, or the like.
  • the light exit surface side is preferably a lens forming surface
  • the light entrance surface side is more preferably a smooth surface or a mat surface.
  • the mat surface is preferably uneven by applying inorganic fine particles or by a shaping roll having an uneven structure.
  • the optical sheet on which the lens portion is formed can be used as a form in which a fine concavo-convex structure made of an ultraviolet curable resin is transferred onto a base material sheet such as a polyester resin, triacetyl cellulose, or polycarbonate.
  • a base material sheet such as a polyester resin, triacetyl cellulose, or polycarbonate.
  • various optical sheets can be used as long as the lens part is formed on the surface.
  • press molding is performed on resin plates such as polystyrene, acrylic resin, polycarbonate, and cycloolefin polymer.
  • a form in which a lens is formed by injection molding or extrusion molding is also preferably used.
  • a form that is press-molded, injection-molded or extruded into a plate shape having a thickness of 1 mm to 2 mm is preferable.
  • An organic polymer having an effect of diffusing light or an inorganic fine particle added therein can be preferably used.
  • optical sheets include Asahi Kasei Diffusion Plate TM DL / DH series (Asahi Kasei E-Materials Co., Ltd.), Zeonore Series (Nihon Zeon Co., Ltd.), and the like.
  • the light source is a line light source, or the light source is a point light source and the arrangement intervals of the point light sources are orthogonal. It can be used in cases where they differ in two directions, and it is preferable that the lens portion of the optical sheet is formed by arranging a plurality of unit lenses, and the bottom shape of the unit lenses is a shape having anisotropy.
  • FIGS. 14A to 14F are diagrams showing examples of the bottom shape of the unit lens.
  • the bottom shape of the unit lens as shown in FIGS. 14A to 14D is preferable, and the bottom surface of the unit lens is preferable. More preferably, the direction in which the shape is strongly anisotropic is parallel to the direction in which the arrangement interval of the point light sources is narrow.
  • the bottom shape of the unit lens as shown in FIGS. 14E and 14F is preferable, and the bottom shape of the unit lens has a strong anisotropic direction, that is, the bottom shape. In the case of an ellipse, it is more preferable that the major axis direction is parallel, and in the case where the bottom shape is a rectangle, the long side direction is parallel to the longitudinal direction of the line light source.
  • the optical sheet constituting the light beam control unit and having a prism array or lenticular lens formed on the surface thereof is preferably used for a line light source, and the longitudinal direction of the line light source and the longitudinal direction of the lens part are arranged in parallel. More preferably.
  • FIGS. 15A and 15B show an example in which the unit lens is a prism array
  • FIG. 15C shows an example in which the unit lens is a lenticular lens.
  • a prism with a rounded tip is preferably used.
  • a structure in which the ridge line of the prism tip is waved as shown in FIG. 15B is also preferably used.
  • the optical sheet constituting a light beam control unit and having a lens portion formed on the surface thereof can be used in the case where the light source is a point light source and the arrangement interval of the point light sources is equal in two orthogonal directions. It is preferable that the lens portion of the sheet is configured by arranging a plurality of unit lenses, and the bottom surface shape of the unit lens is an isotropic shape.
  • FIGS. 16A to 16E show examples of the bottom shape of the unit lens having isotropic properties. From the viewpoint of eliminating luminance unevenness, it is preferable that the unit lenses are densely formed on the sheet surface, and the shape of the bottom surface is as shown in FIGS. 16 (a), (d), and (e).
  • the bottom shape of the unit lens is preferably a circle, a square, or a regular hexagon.
  • the optical sheet constituting the light beam control unit and having a microlens or microprism formed on the surface is preferably used for a point light source.
  • FIGS. 17A and 17B show examples in which the unit lens is a microlens
  • FIGS. 17C to 17E show examples in which the unit lens is a microprism. From the viewpoint of preventing rubbing with other optical sheets, a prism with a rounded tip is preferably used.
  • the microlens or microprism may be concave or convex.
  • the optical sheet that constitutes a light beam control unit and has a lens portion formed on the surface thereof has a light source that is a mixture of a line light source and a point light source, or the light source is a point light source and the arrangement interval of the point light sources is orthogonal. Can be used in the case where there are a mixture of equally spaced regions in the two directions and different regions in the two orthogonal directions, and the lens portion of the optical sheet is configured by arranging a plurality of unit lenses. It is preferable that the bottom surface of the unit lens has a complex array of lenses having anisotropy and isotropic lenses. Examples of the bottom shape of the unit lens formed on the surface of the optical sheet are shown in FIGS. 18 (a) to 18 (e).
  • the luminance unevenness is reduced by optimizing the diffusion angle so that the luminance is constant.
  • the diffusion sheet constituting the light beam control unit shown in the second embodiment has a diffusion angle distribution diagram in the case where the horizontal axis is the relative position in the sheet surface and the vertical axis is the diffusion angle at the position in the sheet surface.
  • the configuration shown in FIG. FIG. 10A to FIG. 10F show examples of diffusion sheets in which the diffusion angle changes in a linear shape, a curved shape, a mixed shape of straight lines and curves, or a staircase shape.
  • the change in the diffusion angle does not have to be strictly linear, curved, or stepped, but may vary slightly from linear, curved, or stepped due to dispersion angle measurement variations, etc. It may be a shape. In particular, it is preferable that the diffusion angle changes smoothly in the plane of the diffusion sheet.
  • FIG. 11A to FIG. 11F show examples of diffusion sheets in which the aspect ratio changes in a linear shape, a curved shape, a mixed shape of straight lines and curves, or a staircase shape.
  • the change in aspect ratio does not have to be strictly linear, curved, or stepped.
  • the shape is slightly different from linear, curved, or stepped, or a mixture of lines and curves. It may be a shape. It is preferable that the aspect ratio changes smoothly in the plane of the diffusion sheet.
  • the diffusion sheet of Embodiment 1 can be used here. Examples include those in which the diffusion angle changes in the plane as shown in FIGS. 3 (a) to (f), or those in which the aspect ratio changes as shown in FIGS. 4 (a) to (f). .
  • the diffusion angle of the diffusion sheet constituting the light beam control unit is preferably controlled in the range of 0.1 ° to 120 °.
  • the difference in diffusion angle and the distribution state of the diffusion angle can be adjusted.
  • the luminance unevenness increases.
  • the diffusion angle is preferably controlled in the range of 0.1 ° to 100 °, and more preferably in the range of 0.1 ° to 80 °, in order to obtain high front luminance. preferable.
  • the aspect ratio of the diffusion sheet constituting the light beam control unit is preferably in the range of 0 to 4 from the viewpoint of the effect of reducing luminance unevenness. Further, from the viewpoint of exhibiting the effect of controlling the diffusion of light, it is more preferably 0 to 3, and further preferably 0 to 2.
  • the diffusion angle or unevenness in the part that does not affect the optical characteristics for example, the endmost part that does not require the optical function when the product is manufactured, or the minute area that does not affect the optical characteristics The aspect ratio may deviate from this range.
  • Such a diffusion angle or aspect ratio can be realized by having a large number of concavo-convex structures on the surface of the diffusion sheet as shown in the above embodiment.
  • a large number of uneven structures may be provided on either the light exit surface or the light entrance surface of the diffusion sheet.
  • the surface side where the uneven structure is not provided is a smooth surface, an uneven surface, a mat. It may be a surface. From the viewpoint of improving brightness and reducing unevenness in brightness, the light exit surface side is preferably an uneven surface, and the light entrance surface side is more preferably a smooth surface or a mat surface.
  • a very small amount of beads may be applied to the light incident surface within a range that does not impair optical characteristics in order to prevent damage. Such a case is also included in the smooth surface.
  • a diffusion sheet having this uneven shape on the surface and changing the diffusion angle in a region within the surface of the diffusion sheet can be manufactured by the method described in the first embodiment.
  • Embodiment 3 a light source unit to which the diffusion sheet shown in Embodiment 1 and the light beam control unit shown in Embodiment 2 are applied will be described.
  • FIG. 19 and 20 show a schematic configuration of the light source unit shown in the present embodiment.
  • FIG. 19 shows a case where a cold cathode fluorescent lamp (CCFL) is used as a light source
  • FIG. 20 shows a case where an LED (light emitting diode) is used as a light source.
  • CCFL cold cathode fluorescent lamp
  • LED light emitting diode
  • the light source unit can basically have a configuration including a light source (light source 11 or light source 12) and a diffusion sheet 15 disposed above the light sources 11 and 12 (FIG. 19A). FIG. 20 (a)). Moreover, it is preferable that a reflection sheet 13 for reflecting light is used below the light sources 11 and 12. In this case, the diffusion sheet shown in the first embodiment can be applied as the diffusion sheet 15.
  • an optical sheet, a diffusion sheet or the like may be further provided.
  • an optical sheet 14 is provided between the light sources 11 and 12 and the diffusion sheet 15. It can be set as a structure (refer FIG.19 (b) and FIG.20 (b)).
  • the light beam control unit shown in the second embodiment can be applied as the light beam control unit including the diffusion sheet 15 and the optical sheet 14.
  • the lens surface side of the optical sheet is preferably a light exit surface
  • the unevenness forming surface side of the diffusion sheet is more preferably a light exit surface.
  • the reflection sheet 13 various materials can be used as long as they can reflect light.
  • a resin such as polyester or polycarbonate is foamed and fine air particles are made into a sheet, and a sheet is formed by mixing two or more resins, and resin layers with different refractive indexes are laminated. Sheet, etc. can be used.
  • the reflection sheet may have a concavo-convex shape on the surface. As these, those having inorganic fine particles added to the surface can be used as necessary.
  • the light source unit uses a plurality of light sources.
  • a linear light source such as a cold cathode tube (CCFL) 11 as shown in FIG. 19 or a point light source such as an LED (light emitting diode) 12 and a laser as shown in FIG. 20 can be used.
  • the light sources 11 and 12 are arranged directly below the light incident surface and the light outgoing surface of the diffusion sheet 15.
  • both an isotropic diffusion sheet that can obtain substantially the same diffusion angle regardless of the measurement direction and an anisotropic diffusion sheet that has a different diffusion angle depending on the measurement direction can be used.
  • An anisotropic diffusion sheet is, for example, a diffusion sheet having different diffusion angles when the diffusion angles are measured in two orthogonal directions.
  • the light source unit shown in the present embodiment is characterized in that the period of the diffusion angle distribution of the diffusion sheet is equal to the period of the illuminance distribution on the light incident surface of the diffusion sheet.
  • the illuminance distribution on the light incident surface of the diffusion sheet can be measured by, for example, EZCONTRASTXL88 manufactured by ELDIM.
  • the omnidirectional luminance distribution is measured with the apparatus focused on the position where the light incident surface of the diffusion sheet is located, excluding the diffusion sheet, and the integrated luminous flux is calculated from the result. It is measured by repeating the process of obtaining the quantity (Integrated Intensity) in the in-plane measurement target range.
  • FIG. 21 is a schematic diagram of an example of the light source unit as viewed from obliquely above.
  • the diffusion angle is periodically distributed, and the direction in which the diffusion angle is periodically distributed coincides with the direction orthogonal to the longitudinal direction of the CCFL light source 11. Is arranged.
  • FIG. 21B has a configuration in which the optical sheet 14 is added to the configuration of FIG.
  • FIG. 22 is a diagram showing a light source interval and a diffusion angle distribution period of the diffusion sheet in the light source unit.
  • the diffusion angle (aspect ratio) distribution period in the diffusion sheet surface is substantially equal to the light source interval.
  • the illuminance distribution on the light incident surface of the diffusion sheet when the illuminance directly above the light source is high, it is preferable to dispose a high diffusion angle (high aspect ratio) region of the diffusion sheet from the viewpoint of eliminating luminance unevenness.
  • FIG. 22 shows an example of the diffusion angle distribution designed to correspond to the illuminance distribution on the light incident surface of the diffusion sheet.
  • the diffusion angle of the diffusion sheet 15 is preferably controlled in the range of 0.1 ° to 120 °.
  • a diffusion plate containing a diffusion agent is disposed between the light sources 11 and 12 and the diffusion sheet 15. It is preferably controlled in the range of 0.1 ° to 100 °, more preferably 0.1 ° to 80 °.
  • an optical sheet having an arrayed prism arrangement structure for example, when an optical sheet having an arrayed prism arrangement structure is disposed above the diffusion sheet 15, it is 0.1 ° or more and It is preferably controlled within a range of 80 ° or less.
  • the concavo-convex height is controlled within the range of 0 ⁇ m to 20 ⁇ m (aspect ratio of 0 to 4) from the viewpoint that moire does not occur even when the liquid crystal has a high definition (pixel narrowing). It is preferable.
  • a diffusion plate containing a diffusion agent is disposed between the light sources 11 and 12 and the diffusion sheet 15. It is preferably controlled in the range of 0 ⁇ m to 15 ⁇ m (aspect ratio 0 to 3), more preferably in the range of 0 ⁇ m to 10 ⁇ m (aspect ratio 0 to 2).
  • an optical sheet having an arrayed prism arrangement structure when used in combination with an optical sheet having an arrayed prism arrangement structure, for example, when an optical sheet having an arrayed prism arrangement structure is disposed above the diffusion sheet 15, 0 ⁇ m to 10 ⁇ m (aspect ratio) It is preferably controlled in the range of 0-2).
  • the diffusion plate 14 various materials can be used as long as they can diffuse light.
  • polystyrene, acrylic resin, polycarbonate, cycloolefin polymer, or the like added with an organic polymer or inorganic fine particles having an effect of diffusing light can be used. These diffusers have the effect of diffusing light and making the light from the lower light source uniform.
  • the diffusion plate 14 may have an uneven shape on the surface. These may be added with the organic polymer or inorganic fine particles as required.
  • a diffusion plate in which two or more components are mixed and stretched to form a sheet can also be used.
  • the arrangement configuration shown in FIGS. 23 (a) to 23 (c) can be adopted.
  • FIG. 23A shows a surface-shaped diffusion sheet in which a fine uneven structure is formed on the surface between the diffusion plate 14 and the diffusion sheet 15 arranged immediately above the light source in the configuration shown in FIG. 19B.
  • 16 shows a light beam control unit in which the surface-shaped diffusion sheet 16 is disposed immediately above the diffusion sheet 15.
  • the surface-shaped diffusion sheet 16 a sheet in which spherical beads of acrylic resin are coated on a sheet of polyester resin, triacetyl cellulose, polycarbonate, or the like can be used.
  • transferred on sheets such as a polyester-type resin, a triacetyl cellulose, or a polycarbonate can be used.
  • Such a surface shaping type diffusion sheet 16 has a function of condensing the light diffused by the diffusion plate 14 as well as the effect of diffusing and uniformizing the light.
  • FIG. 23B shows an optical sheet 17 having an array-like prism arrangement structure and fine irregularities above the diffusion plate 14 and the diffusion sheet 15 arranged immediately above the light source in the configuration shown in FIG. 1 shows a light beam control unit in which a surface-shaped diffusion sheet 16 having a structure formed on the surface thereof is arranged in this order.
  • FIG. 23C shows a surface-shaped diffusion in which a fine concavo-convex structure is formed on the surface above the diffusion plate 14 and the diffusion sheet 15 disposed immediately above the light source in the configuration shown in FIG. 1 shows a light beam control unit in which a sheet 16 and an optical sheet 17 having an arrayed prism arrangement structure are arranged.
  • an optical sheet in which prism rows having a substantially triangular shape, a substantially trapezoidal shape, and a substantially elliptical shape are arrayed on the surface can be used.
  • a shape obtained by rounding the apex of the cross-sectional shape can also be preferably used from the viewpoint of improving scratch resistance.
  • These prism sheets can be used in a form in which a prism array made of an ultraviolet curable resin is transferred onto a base material sheet such as polyester resin, triacetyl cellulose, or polycarbonate. Since such a prism sheet 17 exhibits retroreflectivity, it has a function of collecting incident light to the front.
  • luminance unevenness can be reduced, and the light source unit can be made thinner and the number of light sources can be reduced.
  • FIG. 24 shows a surface-shaped diffusion sheet 16 having a fine concavo-convex structure formed on the surface above the diffusion plate 14 and the diffusion sheet 15 disposed immediately above the light source in the configuration shown in FIG.
  • a light beam control unit in which an optical sheet 17 having an array of prism rows and a reflective polarizing sheet 18 are arranged in this order is shown.
  • the reflective polarizing sheet 18 a sheet having a function of separating linearly polarized light from natural light or polarized light can be used.
  • separates the said linearly polarized light the film etc. which permeate
  • a resin polycarbonate, acrylic resin, polyester resin, etc.
  • a resin (cycloolefin polymer, etc.) having a small birefringence retardation are alternately used.
  • a sheet obtained by multilayer lamination and uniaxial stretching, a sheet having a structure in which several hundred layers of birefringent polyester resin are laminated (DBEF, manufactured by 3M Co., Ltd.), and the like can be used.
  • the configuration of the light source unit for example, the arrangement configuration shown in FIGS. 25 and 26 can be adopted.
  • FIG. 25A shows a light source in which a diffusion plate 14 is disposed between the light source 11 and the diffusion sheet 15 and a lens sheet 16 is disposed immediately above the diffusion sheet 15 in the configuration shown in FIG. Indicates a unit.
  • FIG. 25B shows a light source unit in which the diffusion plate 14 and the lens sheet 16 are arranged in this order above the diffusion sheet 15 in the configuration shown in FIG.
  • FIG. 25C shows an optical system in which a diffusion plate 14 is arranged between the light source 11 and the diffusion sheet 15 in the configuration shown in FIG. 19A and an array-like prism arrangement structure is provided above the diffusion sheet 15.
  • a light source unit in which a sheet (hereinafter abbreviated as a prism sheet) 17 and a reflective polarizing sheet 18 are arranged in this order is shown.
  • FIG. 25D shows a configuration in which the diffusion plate 14 is disposed between the light source 11 and the diffusion sheet 15 in the configuration shown in FIG.
  • a light source unit is shown in which two pieces are arranged so as to be orthogonal to each other and a lens sheet 16 is further disposed thereon.
  • FIG. 26A shows a configuration in which the diffusion plate 14 is disposed between the light source 11 and the diffusion sheet 15 in the configuration shown in FIG. 19A, and the lens sheet 16, the prism sheet 17, and the A light source unit in which the reflective polarizing sheets 18 are arranged in this order is shown.
  • FIG. 26B in the configuration shown in FIG. 19A, the diffusion plate 14, the lens sheet 16, the prism sheet 17, and the reflective polarizing sheet 18 are arranged in this order above the diffusion sheet 15. The light source unit is shown.
  • Example 1 corresponds to the contents shown in the first embodiment.
  • the diffusion angle shown in Example 1 is an angle measured by Photon after entering from a surface having a fine concavo-convex structure. For example, 5 ° indicates that the FWHM in any direction is 5 °.
  • FWHM was measured at intervals of 2 mm with respect to the x-axis direction and / or the y-axis direction of the diffusion sheet, and a distribution map was created.
  • the diffusion angle distributions of Examples 2 and 3 are similarly measured.
  • the aspect ratio was measured at an interval of 4 mm with respect to the x-axis direction and / or y-axis direction of the diffusion sheet using an ultra-deep color 3D shape measurement microscope (VK-9500) manufactured by Keyence Corporation. Asked.
  • VK-9500 ultra-deep color 3D shape measurement microscope
  • Examples 1-1 and 1-2 which are not described in the examples as optical sheets, that is, a reflection sheet, a diffusion plate, a surface-shaped diffusion sheet, and an optical sheet having an arrayed prism arrangement structure
  • the reflective polarizing sheet is a white reflective sheet made of polyester resin (hereinafter abbreviated as RS), a diffuser plate made of polystyrene and having a thickness of 1.5 mm and a diffusing agent concentration of 13000 ppm (hereinafter abbreviated as DP),
  • a diffusion sheet hereinafter abbreviated as DS in which resin beads and a binder are coated on a PET substrate having a thickness of 250 ⁇ m, and a prism array having an apex angle of 90 ° and a pitch of 50 ⁇ m is formed on the PET substrate having a thickness of 250 ⁇ m.
  • Example 1-1 a CCFL light source having a diameter of 3.0 mm ⁇ and a length of 710 mm was used as the light source of the light beam control unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and 16 are arranged so that the distance p between the light sources is 23.7 mm.
  • a light control unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 75 cm away from the light control unit, and the average luminance value measured in the range of 20 mm ⁇ 190 mm in the center of the light control unit. Brightness.
  • CA2000 Konica Minolta two-dimensional color luminance meter
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value at each point by the average luminance value for ⁇ 11.8 mm from each point ( In the following, luminance unevenness was obtained.
  • the luminance unevenness determination criteria were classified into two stages ( ⁇ , ⁇ ) as follows. ⁇ : S. D. ⁇ 0.004 X: 0.004 ⁇ S. D.
  • Example 1-1 As shown in FIG. 26 (a), DP, the diffusion sheet of the present invention, DS, the prism sheet, and DBEF were arranged in this order above the light source to constitute the light control unit of Example 1-1.
  • the diffusion angle of the projection area of the light source is 70 °
  • the diffusion angle of the projection area of the intermediate point between the light source and the light source is 1 °
  • the diffusion sheet used was used so that the uneven surface became the light exit surface.
  • the distance z between the CCFL light source and the light incident surface of the DP was set to 4.5 mm.
  • the luminance unevenness in the light beam control unit of Example 1-1 was calculated by the above method.
  • the aspect ratio distribution of this diffusion sheet shows the same distribution as the curved shape of FIG. 28B, which is 0.8 in the projection area of the light source and 0.14 in the projection area of the intermediate point between the light source and the light source.
  • the arithmetic average value (Av1) of the peak value of the aspect ratio and the bottom value of the aspect ratio is 0.47, and the aspect ratio of all measurement points distributed between the peak value of the continuous aspect ratio and the bottom value of the aspect ratio.
  • the arithmetic average value (Av2) of the ratio is 0.32.
  • Example 1-2 a CCFL light source having a diameter of 3.0 mm ⁇ and a length of 710 mm was used as the light source of the light beam control unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and eight are arranged so that the distance p between the light sources is 47.6 mm.
  • a light control unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 75 cm away from the light control unit, and the average luminance value measured in the range of 20 mm ⁇ 190 mm in the center of the light control unit. Brightness.
  • CA2000 Konica Minolta two-dimensional color luminance meter
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 23.8 mm from each point. Luminance unevenness was obtained.
  • Example 1-2 As shown in FIG. 26 (a), DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute the light control unit of Example 1-2.
  • the diffusion angle of the projection area of the light source is 30 °
  • the diffusion angle of the projection area of the intermediate point between the light source and the light source is 1 °
  • the diffusion sheet to be used was used so that the uneven surface becomes the light exit surface.
  • the distance z between the CCFL light source and the light incident surface of the DP was set to 4.5 mm.
  • the luminance unevenness in the light beam control unit of Example 1-2 was calculated by the above method.
  • the optical sheet that is not described in the examples, that is, the reflective sheet, the diffusion plate, the surface-shaped diffusion sheet, the optical sheet having the arrayed prism arrangement structure, and the reflective polarizing sheet Is a white reflective sheet (hereinafter abbreviated as RS) made of polyester resin, polystyrene, a diffusion plate (hereinafter abbreviated as DP) with a thickness of 2.0 mm and a diffusing agent concentration of 20000 ppm, and a PET base with a thickness of 250 ⁇ m.
  • RS white reflective sheet
  • DP diffusion plate
  • PET base with a thickness of 250 ⁇ m.
  • Diffusion sheet (hereinafter abbreviated as DS) with resin beads and binder coated on the material, prism array with apex angle of 90 ° and pitch of 50 ⁇ m is formed with UV curable resin on 250 ⁇ m thick PET substrate
  • An optical sheet (hereinafter abbreviated as prism sheet) and a reflective polarizing sheet (hereinafter abbreviated as DBEF; manufactured by 3M Company) were used.
  • Example 1-3 a white LED light source of 3.5 mm square and 2.0 mm height made by CREE was used as the light source of the light control unit.
  • the distance between the centers of the light sources was set to 30.0 mm in the x-axis direction and the y-axis direction, and 10 rows were arranged in a grid to arrange a light control unit.
  • Luminance and luminance unevenness were measured using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed at a distance of 70 cm from the light control unit, and an average luminance value measured in a range of 120 mm ⁇ 120 mm at the center of the light control unit. Brightness.
  • CA2000 color luminance meter
  • the luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction.
  • an average luminance value in the x-axis (120 mm) direction is obtained, and luminance unevenness is obtained as a standard deviation of values obtained by dividing the luminance value of each point by the average luminance value of ⁇ 12 mm from each point in the y-axis direction.
  • an average luminance value in the y-axis (100 mm) direction is obtained, and luminance unevenness is obtained as a standard deviation of values obtained by dividing the luminance value of each point by the average luminance value of ⁇ 15 mm from each point in the x-axis direction. Asked.
  • the LED light source is a point light source, as shown in FIG. 2 (b)
  • the diffusion angle distribution is distributed on a line (dashed line in FIG. 2 (b)) that maximizes the linear distance between adjacent light sources.
  • Example 1-3 As shown in FIG. 24A, DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute the light control unit of Example 1-3.
  • the diffusion angle of the projection area of the light source is 60 °
  • the diffusion angle of the projection area of the intermediate point between the light source and the light source is 20 °
  • the diffusion sheet used was used so that the uneven surface became the light exit surface.
  • the distance h between the light incident surface of RS and DP was set to 16.0 mm.
  • the luminance unevenness in the light beam control unit of Example 1-3 was calculated by the above method.
  • optical sheets that are not described in the examples, that is, a reflection sheet, a diffusion plate, a surface-shaped diffusion sheet, and an optical sheet having an arrayed prism arrangement structure
  • the reflective polarizing sheet is a white reflective sheet made of polyester resin (hereinafter abbreviated as RS), a diffuser plate made of polystyrene and having a thickness of 1.5 mm and a diffusing agent concentration of 13000 ppm (hereinafter abbreviated as DP),
  • a diffusion sheet hereinafter abbreviated as DS in which resin beads and a binder are coated on a PET substrate having a thickness of 250 ⁇ m, and a hemispherical lens is formed by a UV curable resin on a PET substrate having a thickness of 250 ⁇ m.
  • An optical sheet (hereinafter abbreviated as MLF), a prism array with an apex angle of 90 ° and a pitch of 50 ⁇ m on a 250 ⁇ m thick PET substrate is UV cured.
  • An optical sheet hereinafter abbreviated as “prism sheet” and a reflective polarizing sheet (hereinafter abbreviated as “DBEF”; manufactured by 3M) were used.
  • a CCFL light source having a diameter of 3.0 mm ⁇ and a length of 710 mm was used as the light source of the light beam control unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and 16 are arranged so that the distance p between the light sources is 23.7 mm.
  • a light control unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 75 cm away from the light control unit, and the average luminance value measured in the range of 20 mm ⁇ 190 mm in the center of the light control unit. Brightness.
  • CA2000 Konica Minolta two-dimensional color luminance meter
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value at each point by the average luminance value for ⁇ 11.8 mm from each point ( In the following, luminance unevenness was obtained.
  • Example 1-4 As shown in FIG. 26 (a), DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute the light control unit of Example 1-4.
  • the diffusion angle of the projection area of the light source is 70 °
  • the diffusion angle of the projection area of the intermediate point between the light source and the light source is 1 °
  • the diffusion sheet used was used so that the uneven surface became the light exit surface.
  • the distance z between the CCFL light source and the light incident surface of the DP was set to 4.5 mm.
  • the luminance unevenness in the light beam control unit of Example 1-4 was calculated by the above method.
  • Example 1-5 a CCFL light source having a diameter of 3.0 mm ⁇ and a length of 710 mm was used as the light source of the light beam control unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and eight are arranged so that the distance p between the light sources is 47.6 mm.
  • a light control unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 75 cm away from the light control unit, and the average luminance value measured in the range of 20 mm ⁇ 190 mm in the center of the light control unit. Brightness.
  • CA2000 Konica Minolta two-dimensional color luminance meter
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 23.8 mm from each point. Luminance unevenness was obtained.
  • Example 1-5) DP, the diffusion sheet of the present invention, MLF, and MLF were disposed in this order above the light source to constitute the light control unit of Example 1-5.
  • the diffusion angle of the projection area of the light source is 59 °
  • the diffusion angle of the projection area of the intermediate point between the light source and the light source is 25 °
  • the diffusion sheet used was used so that the uneven surface became the light exit surface.
  • the distance z between the CCFL light source and the light incident surface of the DP was set to 4.5 mm.
  • the luminance unevenness in the light beam control unit of Example 1-5 was calculated by the above method. The results are shown in Table 3 below.
  • the diffusion sheet of the present invention the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value.
  • the arithmetic average value (Av2) of the angle is also shown in Table 3 below.
  • optical sheets that are not described in the examples, that is, a reflection sheet, a diffusion plate, a surface-shaped diffusion sheet, a microlens sheet, and an array prism
  • the optical sheet and the reflective polarizing sheet having an array structure are respectively a white reflective sheet made of polyester resin (hereinafter abbreviated as RS) and a polystyrene, a diffusion plate having a thickness of 2.0 mm and a diffusing agent concentration of 20000 ppm.
  • DP Abbreviated as DP
  • DS diffusion sheet
  • MLF Optical sheet formed by a conductive resin, apex angle 90 °, pitch 50 ⁇ m on a 250 ⁇ m thick PET base material
  • prism sheet An optical sheet (hereinafter abbreviated as “prism sheet”) and a reflective polarizing sheet (hereinafter abbreviated as “DBEF”, manufactured by 3M) were used.
  • Example 1-6 a white LED light source of 3.5 mm square and 2.0 mm height manufactured by CREE was used as the light source of the light control unit.
  • the LEDs are arranged in a staggered pattern as shown in FIG. 30A (a and b are distances between the centers of the light sources).
  • Ten LEDs were arranged side by side in the X and Y directions to produce a light beam control unit.
  • Luminance and luminance unevenness were measured using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed at a distance of 70 cm from the light control unit, and an average luminance value measured in a range of 120 mm ⁇ 120 mm at the center of the light control unit. Brightness.
  • CA2000 color luminance meter
  • the luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction.
  • an average luminance value in the x-axis (120 mm) direction is obtained, and in the y-axis direction, luminance is obtained as a standard deviation of values obtained by dividing the luminance value at each point by the average luminance value for ⁇ 20.8 mm from each point. I asked for unevenness.
  • the average luminance value in the y-axis (120 mm) direction is obtained, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 15.2 mm from each point in the x-axis direction. Luminance unevenness was obtained.
  • the LED light source is a point light source, as shown in FIG. 2 (b)
  • the diffusion angle distribution is distributed on a line (dashed line in FIG. 2 (b)) that maximizes the linear distance between adjacent light sources.
  • Example 1-7 a white LED light source of 3.5 mm square and a height of 2.0 mm manufactured by CREE was used as the light source of the light control unit.
  • the LEDs were arranged in a staggered pattern as shown in FIG. 30B (a and b are distances between the centers of the light sources).
  • Ten LEDs were arranged side by side in the X and Y directions to produce a light beam control unit.
  • Luminance and luminance unevenness were measured using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed at a distance of 70 cm from the light control unit, and an average luminance value measured in a range of 120 mm ⁇ 120 mm at the center of the light control unit. Brightness.
  • CA2000 color luminance meter
  • the luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction.
  • an average luminance value in the x-axis (120 mm) direction is obtained, and in the y-axis direction, luminance is obtained as a standard deviation of values obtained by dividing the luminance value at each point by the average luminance value for ⁇ 25.2 mm from each point. I asked for unevenness.
  • the average luminance value in the y-axis (120 mm) direction is obtained, and the standard deviation of the value obtained by dividing the luminance value of each point by the luminance average value for ⁇ 17.2 mm from each point in the x-axis direction. Luminance unevenness was obtained.
  • the LED light source is a point light source, as shown in FIG. 2 (b)
  • the diffusion angle distribution is distributed on a line (dashed line in FIG. 2 (b)) that maximizes the linear distance between adjacent light sources.
  • Example 1-8 a white LED light source of 3.5 mm square and 2.0 mm height manufactured by CREE was used as the light source of the light control unit.
  • the LEDs were arranged in a square lattice pattern as shown in FIG. 30C (a and b are distances between the centers of the light sources).
  • Ten LEDs were arranged side by side in the X and Y directions to produce a light beam control unit.
  • Luminance and luminance unevenness were measured using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed at a distance of 70 cm from the light control unit, and an average luminance value measured in a range of 120 mm ⁇ 120 mm at the center of the light control unit. Brightness.
  • CA2000 color luminance meter
  • the luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction.
  • an average luminance value in the x-axis (120 mm) direction is obtained, and in the y-axis direction, the luminance as a standard deviation of a value obtained by dividing the luminance value at each point by the average luminance value for ⁇ 24.75 mm from each point. I asked for unevenness.
  • the average luminance value in the y-axis (120 mm) direction is obtained, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 27.5 mm from each point in the x-axis direction. Luminance unevenness was obtained.
  • the LED light source is a point light source, as shown in FIG. 2 (b)
  • the diffusion angle distribution is distributed on a line (dashed line in FIG. 2 (b)) that maximizes the linear distance between adjacent light sources.
  • Example 1-6 DP, the diffusion sheet of the present invention, DS, DS, and DBEF were arranged in this order above the light source to constitute the light control unit of Example 1-6.
  • the diffusion angle of the projection area of the light source is 82 °
  • the diffusion angle of the projection area of the intermediate point between the light source and the light source is 19 °
  • the diffusion sheet was used so that the uneven surface becomes the light exit surface.
  • the distance h between the light incident surface of RS and DP was set to 17.0 mm.
  • the luminance unevenness in the light beam control unit of Example 1-6 was calculated by the above method. The results are shown in Table 4 below.
  • the diffusion sheet of the present invention the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value.
  • the arithmetic average value (Av2) of the angle is shown in Table 4 below.
  • Example 1--7 DP, the diffusion sheet of the present invention, MLF, MLF, and DBEF were arranged in this order above the light source to constitute the light control unit of Example 1-7.
  • the diffusion angle of the projection area of the light source is 64 °
  • the diffusion angle of the projection area of the intermediate point between the light source and the light source is 8 °
  • the diffusion sheet was used so that the uneven surface becomes the light exit surface.
  • the distance h between the light incident surface of RS and DP was set to 20.0 mm.
  • the luminance unevenness in the light beam control unit of Example 1-7 was calculated by the above method. The results are shown in Table 4 below.
  • the diffusion sheet of the present invention the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value.
  • the arithmetic average value (Av2) of the angle is also shown in Table 4 below.
  • Example 1-8 As shown in FIG. 24, the DP, the diffusion sheet of the present invention, the MLF, the prism sheet, and the DBEF are arranged in this order above the light source to constitute the light control unit of Example 1-8.
  • the diffusion angle of the projection area of the light source is 62 °
  • the diffusion angle of the projection area of the intermediate point between the light source and the light source is 12 °
  • the diffusion sheet was used so that the uneven surface becomes the light exit surface.
  • the distance h between the light incident surface of RS and DP was 40.0 mm.
  • the luminance unevenness in the light beam control unit of Example 1-8 was calculated by the above method. The results are shown in Table 4 below.
  • the diffusion sheet of the present invention the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value.
  • the arithmetic average value (Av2) of the angle is also shown in Table 4 below.
  • the diffusion sheet of the present invention has all measurements distributed between the continuous diffusion angle peak value and the diffusion angle bottom value, rather than the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value. It can be seen that when the arithmetic average value (Av2) of the point diffusion angle is low, the luminance unevenness can be suppressed and the light source unit can be thinned.
  • the diffusion angle shown in Example 2 is calculated from the result of measuring the angle distribution of the transmitted light intensity with respect to the light incident in the normal direction of the concavo-convex surface with the diffusing surface of the diffusing sheet as the incident surface, using a goniophotometer. ing. For example, 5 ° indicates that the diffusion angle in any direction is 5 °.
  • the diffusion sheet having a diffusion angle distribution in the sheet surface described in the examples and comparative examples the diffusion angle periodically changes in one direction in the sheet surface, and further includes a light source unit including the diffusion sheet ,
  • the direction orthogonal to the longitudinal direction of the CCFL light source is matched with the direction in which the diffusion angle periodically changes.
  • the diffusion angle distribution in the surface of the diffusion sheet was designed so as to correspond to the illuminance distribution from the light source, and a region where the diffusion angle of the diffusion sheet was high was arranged and used in a region where the illuminance was high.
  • optical sheets that are not described in the examples, that is, a reflective sheet, a diffuser plate, a lens sheet, a prism sheet, and a reflective polarizing sheet are used.
  • a white reflective sheet hereinafter abbreviated as RS
  • RS white reflective sheet
  • silicon fine particles having a particle size of 2 ⁇ m and a true specific gravity of 1.35 as a diffusing agent, and having a thickness of 1.5 mm.
  • DP lens sheet
  • DS lens sheet
  • prism sheet Prism sheet
  • DBEF reflective type A polarizing sheet
  • a CCFL light source having a diameter of 3.0 mm ⁇ and a length of 710 mm was used as the light source of the light source unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and 16 are arranged so that the distance p between the light sources is 23.7 mm.
  • a light source unit was prepared. The brightness and brightness unevenness were measured by using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed 75 cm away from the light source unit, and the average brightness value measured in the range of 20 mm ⁇ 190 mm in the center of the light source unit as brightness.
  • CA2000 two-dimensional color luminance meter
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 11.8 mm from each point in the y-axis direction. Luminance unevenness was obtained.
  • the judgment criteria for luminance unevenness were classified into the following three levels ( ⁇ , ⁇ , ⁇ ).
  • Example 2-1 and Example 2-2 and Comparative Example 2-1 were evaluated in a light source unit having a basic configuration as shown in FIG.
  • Example 2-1 As shown in FIG. 26 (a), the light source unit of Example 2-1 was configured by arranging DP, the diffusion sheet of the present invention, DS, the prism sheet, and DBEF in this order above the light source.
  • the diffusion sheet of the present invention has a maximum diffusion angle of 70 °, a minimum value of 1 °, and a diffusion angle difference of 69 °.
  • the diffusion angle is within the plane of the diffusion sheet.
  • the diffusion sheet in which is distributed is disposed so that the uneven surface becomes the light exit surface.
  • the distance h between the CCFL light source and the light incident surface of the DP was 4.5 mm.
  • the luminance in the light source unit of Example 2-1 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 5 below.
  • Example 2-2 As shown in FIG. 25 (c), a diffusion plate formed with a lenticular lens, the diffusion sheet of the present invention, a prism sheet, and DBEF are arranged in this order above the light source, and the light source of Example 2-2 Configured the unit.
  • the diffusion plate used in Example 2-2 is made of polystyrene having a thickness of 1.5 mm, contains 2000 ppm of a diffusing agent inside, a lenticular lens having a height of 130 ⁇ m and a pitch of 320 ⁇ m is formed in the longitudinal direction of the CCFL light source. Are formed in parallel with each other.
  • the maximum value of the diffusion angle is 80 °
  • the minimum value of the diffusion angle is 40 °
  • the difference in diffusion angle is 40 °.
  • the diffusion sheet in which the diffusion angle is distributed is arranged so that the uneven surface becomes the light exit surface.
  • the distance h between the CCFL light source and the light incident surface of the diffusion plate was 4.5 mm.
  • the luminance in the light source unit of Example 2-2 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 5 below.
  • (Comparative Example 2-1) As shown in FIG. 26 (a), DP, a diffusion sheet having a concavo-convex structure formed using a speckle pattern by interference exposure on the surface, DS, a prism sheet, and DBEF are arranged in this order above the light source. Thus, the light source unit of (Comparative Example 2-1) was configured.
  • the diffusion sheet used in Comparative Example 2-1 has a diffusion angle of 71 ° in the entire region within the sheet surface.
  • the said diffusion sheet was arrange
  • the distance h between the CCFL light source and the light incident surface of the diffusion sheet was 4.5 mm.
  • the luminance in the light source unit of Comparative Example 2-1 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 5 below.
  • Example 2-3 and Comparative Example 2-2 were evaluated in a light source unit having a basic configuration as shown in FIG.
  • Example 2-3 As shown in FIG. 26 (b), the diffusion sheet, DP, DS, prism sheet, and DBEF of the present invention were arranged in this order above the light source to constitute a light source unit of Example 2-3.
  • the diffusion sheet of the present invention has a maximum diffusion angle of 70 °, a minimum value of 1 °, and a diffusion angle difference of 69 °. As shown in FIG. 10B, the diffusion angle is within the plane of the diffusion sheet.
  • the diffusion sheet in which is distributed is disposed so that the uneven surface becomes the light exit surface.
  • the distance h between the CCFL light source and the light incident surface of the diffusion sheet was set to 9.1 mm.
  • the luminance in the light source unit of Example 2-3 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 6 below.
  • Comparative Example 2-2 As shown in FIG. 26 (b), a diffusion sheet having a concavo-convex structure formed on the surface using a speckle pattern by interference exposure, DP, DS, prism sheet, and DBEF are arranged in this order above the light source.
  • the diffusion sheet used in Comparative Example 2-2 has a diffusion angle of 71 ° in the entire region.
  • the said diffusion sheet was arrange
  • the distance h between the CCFL light source and the light incident surface of the diffusion sheet was set to 9.1 mm.
  • the luminance in the light source unit of Comparative Example 2-2 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 6 below.
  • the diffusion sheet of the present invention has a diffusion angle difference in the range of 40 ° to 80 °.
  • the luminance unevenness could be reduced.
  • Example 2-4 a CCFL light source having a diameter of 3.4 mm ⁇ and a length of 710 mm was used as the light source of the light source unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and eight are arranged so that the distance p between the light sources is 47.6 mm.
  • a light source unit was prepared. The brightness and brightness unevenness were measured by using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed 75 cm away from the light source unit, and the average brightness value measured in the range of 20 mm ⁇ 190 mm in the center of the light source unit as brightness. did.
  • CA2000 two-dimensional color luminance meter
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 23.8 mm from each point. Luminance unevenness was obtained.
  • the judgment criteria for luminance unevenness were classified into the following three levels ( ⁇ , ⁇ , ⁇ ).
  • Example 2-4 was evaluated in a light source unit having a basic configuration as shown in FIG.
  • the light source unit of Example 2-4 was configured by arranging DP, the diffusion sheet of the present invention, DS, the prism sheet, and DBEF in this order above the light source.
  • the diffusion sheet of the present invention has a maximum diffusion angle value of 50 °, a minimum diffusion angle value of 1 °, and a diffusion angle difference of 49 °.
  • the diffusion sheet in which the diffusion angle is distributed was used so that the uneven surface becomes the light exit surface.
  • the distance h between the CCFL light source and the light incident surface of the DP was 14.5 mm.
  • the luminance in the light source unit of Example 2-4 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 7 below.
  • a diffusion sheet having a concavo-convex structure characterized by DP above the light source and non-planar speckles on the surface and having a diffusion angle of 41 ° over the entire region, DS , Prism sheet, and DBEF were arranged in this order to constitute a light source unit of Comparative Example 2-3.
  • the said diffusion sheet was used so that an uneven surface might become a light emission surface.
  • the distance h between the CCFL light source and the light incident surface of the DP was 14.5 mm.
  • the luminance and luminance unevenness in the light source unit of Comparative Example 2-3 were measured by the above method. The results are also shown in Table 7 below.
  • the diffusion sheet of the present invention has a diffusion angle difference in the range of 40 ° to 80 °.
  • the luminance unevenness could be reduced.
  • the center-to-center distance p of the diameter of the CCFL light source can be increased approximately twice as compared with Comparative Example 2-3 (FIG. 27). (B)) As a result, it can be seen that the number of CCFL light sources can be reduced.
  • Example 2-5 In Example 2-5, Example 2-6, Comparative Example 2-4, and Comparative Example 2-5, what is not particularly described as an optical sheet, that is, a reflection sheet, a diffusion plate, a lens sheet, a prism sheet, a reflection
  • Each of the polarizing plates is a white reflective sheet (hereinafter abbreviated as RS) made of a polyester resin, polystyrene, and contains 20000 ppm of silicone fine particles having a particle size of 2 ⁇ m and a true specific gravity of 1.35 as a diffusing agent.
  • RS white reflective sheet
  • DP 0.0 mm diffusion plate
  • DS diffusion sheet coated with resin beads and binder on a 250 ⁇ m thick PET base material
  • Prism sheet (hereinafter abbreviated as “prism sheet”) in which prism rows with an apex angle of 90 ° and a pitch of 50 ⁇ m are shaped by a UV curable resin
  • DBEF reflective polarizing sheet
  • a white light of 3.5 mm square and 2.0 mm height made by CREE was used as the light source of the light source unit.
  • An LED light source was used.
  • the distance between the centers of the light sources was set to 24.0 mm in the x-axis direction and the y-axis direction, and 10 rows were arranged in a grid and arranged to form a light source unit.
  • the brightness and brightness unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 70 cm away from the light source unit, and an average brightness value measured in the range of 120 mm ⁇ 120 mm in the center of the light source unit as brightness. did.
  • CA2000 Konica Minolta two-dimensional color luminance meter
  • the luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction.
  • an average luminance value in the x-axis (120 mm) direction is obtained, and luminance unevenness is obtained as a standard deviation of values obtained by dividing the luminance value of each point by the average luminance value of ⁇ 12 mm from each point in the y-axis direction.
  • the average luminance value in the y-axis (100 mm) direction is obtained, and the luminance unevenness is obtained as a standard deviation of values obtained by dividing the luminance value of each point by the average luminance value of ⁇ 12 mm from each point in the x-axis direction. Asked.
  • a value obtained by averaging the standard deviation in the x-axis direction and the standard deviation in the y-axis direction was used as the luminance unevenness of the light source unit. Since the LED light source is a point light source, the distribution of diffusion angles on the x-axis and the y-axis was considered as shown in FIG. Here, the judgment criteria for luminance unevenness were classified into the following three levels ( ⁇ , ⁇ , ⁇ ).
  • Example 2-5 As shown in FIG. 24, the DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute a light source unit of Example 2-5.
  • the maximum value of the diffusion angle is 70 °
  • the minimum value of the diffusion angle is 10 °
  • the diffusion angle difference is 60 °.
  • FIG. 10B the diffusion angle changes.
  • the diffusion sheet used was used so that the uneven surface became the light exit surface.
  • the distance h between the light incident surface of RS and DP was set to 16.0 mm.
  • the luminance in the light source unit of Example 2-5 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 8 below.
  • Example 2-6 As shown in FIG. 24, the DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute a light source unit of Example 2-6.
  • the maximum value of the diffusion angle is 50 °
  • the minimum value of the diffusion angle is 5 °
  • the difference in diffusion angle is 45 °.
  • the diffusion sheet used was used so that the uneven surface becomes the light incident surface.
  • the distance h between the light incident surface of RS and DP was set to 16.0 mm.
  • the luminance in the light source unit of Example 2-6 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 8 below.
  • Comparative Example 2-4 As shown in FIG. 24, a diffusion sheet having a concavo-convex structure formed using DP above the light source and a speckle pattern formed by interference exposure on the surface, and having a diffusion angle of 70 ° over the entire region, DS , Prism sheet, and DBEF were arranged in this order to constitute a light source unit of Comparative Example 2-4.
  • the said diffusion sheet was used so that an uneven surface might become a light emission surface.
  • the distance h between the light incident surface of RS and DP was set to 16.0 mm.
  • the luminance in the light source unit of Comparative Example 2-4 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 8 below.
  • Comparative Example 2-5 As shown in FIG. 24, a diffusion sheet having a concavo-convex structure formed using DP above the light source and a speckle pattern formed by interference exposure on the surface, and having a diffusion angle of 50 ° over the entire region, DS , Prism sheet, and DBEF were arranged in this order to constitute a light source unit of Comparative Example 2-5.
  • the said diffusion sheet was used so that an uneven surface may become a light-incidence surface.
  • the distance h between the light incident surface of RS and DP was set to 16.0 mm.
  • the luminance in the light source unit of Comparative Example 2-5 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 8 below.
  • Example 3 corresponds to the contents shown in the second embodiment.
  • the diffusion angle shown in Example 3 is based on the result of measuring the angle distribution of the transmitted light intensity with respect to the light incident in the normal direction of the concavo-convex surface with the diffusing sheet concavo-convex surface as an incident surface, using a goniophotometer. Calculated. For example, 5 ° is an isotropic diffusion sheet, and the diffusion angle in any direction within the sheet surface is 5 °. On the other hand, 10 ° ⁇ 5 ° is an anisotropic diffusion sheet, and the diffusion angles in two orthogonal directions within the sheet surface are 10 ° and 5 °.
  • the diffusion sheet having a diffusion angle distribution in the sheet surface described in the examples and comparative examples the diffusion angle periodically changes in one direction in the sheet surface, and further includes a light source unit including the diffusion sheet ,
  • the direction orthogonal to the longitudinal direction of the CCFL light source is matched with the direction in which the diffusion angle periodically changes.
  • the diffusion angle distribution in the surface of the diffusion sheet was designed so as to correspond to the illuminance distribution from the light source, and a region where the diffusion angle of the diffusion sheet was high was arranged and used in a region where the illuminance was high.
  • Example 3-1 and Example 3-2, and Comparative Example 3-1 to Comparative Example 3-3 are made of polystyrene having a thickness of 1.5 mm as an optical sheet according to the light control unit of the present invention.
  • a lens containing 3000 ppm of silicone fine particles with a true specific gravity of 1.35 and an average particle diameter of 2 ⁇ m and having a lenticular lens with a height of 130 ⁇ m and a pitch of 320 ⁇ m formed on the light exit surface (manufactured by Asahi Kasei E-Materials Co., Ltd.) Evaluation was performed in a light source unit in which the longitudinal direction was arranged in parallel with the longitudinal direction of the CCFL light source. The surface on which the lenticular lens was formed was defined as a light exit surface.
  • Examples 3-1 and 3-2, and Comparative Examples 3-1 to 3-3 optical sheets that are not described in the examples, that is, a reflective sheet, a lens sheet, a prism sheet, and a reflective type Regarding the polarizing sheet, a reflective sheet (hereinafter abbreviated as RS), a lens sheet (hereinafter abbreviated as DS), a prism sheet (BEFIII (manufactured by 3M Corporation)) used in BRAVIA KDL32-F1 manufactured by Sony Corporation A reflective polarizing sheet (DBEF (manufactured by 3M Co., Ltd.)) was used.
  • RS reflective sheet
  • DS lens sheet
  • BEFIII manufactured by 3M Corporation
  • DBEF reflective polarizing sheet
  • Example 3-1 For Example 3-1, Example 3-2, and Comparative Examples 3-1 to 3-3, a CCFL light source having a diameter of 3.0 mm ⁇ and a length of 710 mm was used as the light source of the light source unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and 16 are arranged so that the distance p between the light sources is 23.7 mm.
  • a light source unit was prepared.
  • Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000) at a distance of 75 cm from the light source unit, and the average luminance value measured in the range of 20 mm ⁇ 190 mm in the center of the light source unit as luminance. did.
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 11.8 mm from each point in the y-axis direction. Luminance unevenness was obtained.
  • the standard deviation maximum value 0.004 that allows permissible brightness unevenness was used as a boundary, and the determination standard of brightness unevenness was classified into two stages ( ⁇ , ⁇ ) as follows. ⁇ : S. D. ⁇ 0.004 X: 0.004 ⁇ S. D.
  • Example 3-1 As shown in FIG. 25 (c), an optical sheet having a lenticular lens formed on the surface thereof and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source.
  • the prism sheet (BEFIII) and the reflective polarizing sheet (DBEF) were arranged in this order to constitute the light source unit of Example 3-1.
  • the maximum value of the diffusion angle is 70 ° and the minimum value is 50 °, and the diffusion angle is smoothly distributed in the surface of the diffusion sheet as shown in FIG.
  • the diffusion sheet as described above was disposed so that the uneven surface becomes the light exit surface.
  • the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the lenticular lens is formed was 4.6 mm.
  • the luminance in the light source unit of Example 3-1 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 9 below.
  • Example 3-2 As shown in FIG. 26 (a), an optical sheet having a lenticular lens formed on the surface thereof and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source. DS, a prism sheet (BEFIII), and a reflective polarizing sheet (DBEF) were arranged in this order to constitute a light source unit of Example 3-2.
  • the diffusion sheet of the present invention has a maximum diffusion angle of 30 ° and a minimum diffusion angle of 0.1 °, and smoothly diffuses in the plane of the diffusion sheet as shown in FIG. 10 (f). A diffusion sheet in which the angles are distributed was arranged so that the concavo-convex surface was the light exit surface.
  • the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the lenticular lens is formed was 4.6 mm.
  • the luminance in the light source unit of Example 3-2 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 9 below.
  • Example 3-1 An RS is placed below the light source, and an optical sheet with a lenticular lens formed on the surface, DS, prism sheet (BEFIII), and reflective polarizing sheet (DBEF) are placed in this order from the light source and compared.
  • the light source unit of Example 3-1 was configured.
  • the optical sheet on which the lenticular lens was formed was disposed so that the lens forming surface was the light exit surface.
  • the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the lenticular lens is formed was 4.6 mm.
  • the luminance in the light source unit of Comparative Example 3-1 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 9 below.
  • Comparative Example 3-2 An optical sheet in which an RS is arranged below the light source and a lenticular lens is formed on the surface above the light source, a diffusion sheet having a concavo-convex structure formed on the surface using a speckle pattern by interference exposure, DS, and prism sheet , DBEF are arranged in this order to constitute a light source unit of Comparative Example 3-2.
  • the diffusion sheet used in Comparative Example 3-2 has a diffusion angle of 70 ° in the entire region within the sheet surface.
  • the diffusion sheet having the concavo-convex structure is arranged such that the concavo-convex surface becomes a light exit surface, where the distance h between the center of the diameter of the CCFL light source and the light entrance surface of the optical sheet on which the lenticular lens is formed.
  • the luminance in the light source unit of Comparative Example 3-2 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 9 below.
  • Comparative Example 3-3 An optical sheet in which an RS is arranged below the light source and a lenticular lens is formed on the surface above the light source, a diffusion sheet having a concavo-convex structure formed on the surface using a speckle pattern by interference exposure, DS, and prism sheet , DBEF are arranged in this order to constitute a light source unit of Comparative Example 3-3.
  • the diffusion sheet used in Comparative Example 3-3 has a diffusion angle of 30 ° in the entire region within the sheet surface.
  • the diffusion sheet having the concavo-convex structure is arranged such that the concavo-convex surface becomes a light exit surface, where the distance h between the center of the diameter of the CCFL light source and the light entrance surface of the optical sheet on which the lenticular lens is formed.
  • the luminance in the light source unit of Comparative Example 3-3 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 9 below.
  • the light beam control unit of the present invention is compared with the case where the diffusion sheet in which the diffusion angle periodically changes in the sheet surface is not used (Comparative Examples 3-1, 3-2, and 3-3). Brightness unevenness.
  • the optical sheet according to the light control unit of the present invention is made of polystyrene having a thickness of 1.5 mm, and contains a diffusing agent inside.
  • a prism array (R prism) with a height of 100 ⁇ m and a pitch of 300 ⁇ m formed on the light-emitting surface (manufactured by Asahi Kasei E-Materials Co., Ltd.) is used. Evaluation was performed in a light source unit arranged in parallel with the longitudinal direction of the light source. The surface on which the R prism was formed was defined as the light exit surface.
  • Example 3-3 Example 3-4, and Comparative Example 3-5, what is not described in the examples as an optical sheet, that is, for a reflective sheet, a lens sheet, a prism sheet, and a reflective polarizing sheet, Reflective sheet (hereinafter abbreviated as RS), lens sheet (hereinafter abbreviated as DS), prism sheet (BEFIII (manufactured by 3M)), reflective polarizing sheet used in Sony BRAVIA KDL32-JE1 (DBEF (manufactured by 3M)) was used.
  • RS Reflective sheet
  • DS lens sheet
  • BEFIII prism sheet
  • DBEF reflective polarizing sheet used in Sony BRAVIA KDL32-JE1
  • Example 3-3 For Example 3-3, Example 3-4, and Comparative Example 3-5, a CCFL light source having a diameter of 3.4 mm ⁇ and a length of 710 mm was used as the light source of the light source unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.7 mm, and the distance p between the light sources is 87.6 mm.
  • a light source unit was prepared.
  • Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000) at a distance of 75 cm from the light source unit, and the average luminance value measured in the range of 20 mm ⁇ 190 mm in the center of the light source unit as luminance. did.
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 11.8 mm from each point in the y-axis direction. Luminance unevenness was obtained.
  • the determination standard of luminance unevenness was classified into two stages ( ⁇ , ⁇ ) as follows. ⁇ : S. D. ⁇ 0.004 X: 0.004 ⁇ S. D.
  • Example 3-3 As shown in FIG. 26 (a), an optical sheet having a prism array formed on the surface and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source, and further above that. , DS, prism sheet (BEFIII), and reflective polarizing sheet (DBEF) were arranged in this order to constitute a light source unit of Example 3-3.
  • the optical sheet has a prism array (R prism) having a surface with a pitch of 300 ⁇ m and a height of 100 ⁇ m and a rounded tip, and the R prism forming surface was used as a light exit surface.
  • the diffusion sheet according to the light beam control unit of the present invention has a maximum diffusion angle of 60 ° and a minimum value of 0.1 °, and is smooth in the diffusion sheet surface as shown in FIG.
  • a diffusion sheet in which the diffusion angle is distributed was disposed so that the uneven surface becomes the light exit surface.
  • the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the R prism was formed was 8.6 mm.
  • the luminance in the light source unit of Example 3-3 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 10 below.
  • Example 3-4 As shown in FIG. 26 (a), an optical sheet having a prism array formed on the surface and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source, and further above that.
  • Two prism sheets (BEFIII) with the prism extending directions orthogonal to each other and a diffusion sheet having a concavo-convex structure formed by using a speckle pattern formed by interference exposure on the surface are arranged in this order.
  • the light source unit of Example 3-4 was configured.
  • the optical sheet has a prism array (R prism) having a surface with a pitch of 300 ⁇ m and a height of 100 ⁇ m and a rounded tip, and the R prism forming surface was used as a light exit surface.
  • the two prism sheets were arranged from the side close to the light source in parallel with the extending direction of the prism and the longitudinal direction of the CCFL light source and perpendicular to the extending direction of the prism and the longitudinal direction of the CCFL light source.
  • the diffusion sheet according to the light beam control unit of the present invention has a maximum diffusion angle of 60 ° and a minimum value of 0.1 °, and is smooth within the surface of the diffusion sheet as shown in FIG.
  • a diffusion sheet in which the diffusion angle is distributed is arranged so that the uneven surface becomes the light exit surface.
  • the diffusion sheet having the concavo-convex structure has an anisotropy with a diffusion angle of 20 ° ⁇ 10 °, and is arranged so that the diffusion direction of 20 ° is parallel to the longitudinal direction of the CCFL light source.
  • the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the R prism was formed was 6.3 mm.
  • the luminance in the light source unit of Example 3-4 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 10 below.
  • Example 3-5 The light source unit of Example 3-3 has the same configuration except that the diffusion sheet according to the light beam control unit of the present invention is not used, and the light source unit of Comparative Example 3-5 is configured.
  • the luminance in the light source unit of Comparative Example 3-5 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 10 below.
  • the light beam control unit of the present invention is compared with a case where a diffusion sheet whose diffusion angle periodically changes in the sheet surface is not used (Comparative Example 3-5). , Brightness unevenness could be reduced.
  • Examples 3-5, 3-6, Comparative Examples 3-7, and Comparative Examples 3-8 optical sheets that are not described in the examples, that is, a reflective sheet, a lens sheet, a prism sheet, and a reflective type Regarding the polarizing sheet, a reflective sheet (hereinafter abbreviated as RS), a lens sheet (hereinafter abbreviated as DS), a prism sheet (BEFIII (manufactured by 3M Corporation)) used in BRAVIA KDL32-JE1 manufactured by Sony Corporation A reflective polarizing sheet (DBEF (manufactured by 3M Co., Ltd.)) was used.
  • RS reflective sheet
  • DS lens sheet
  • BEFIII manufactured by 3M Corporation
  • DBEF reflective polarizing sheet
  • Example 3-5 For Example 3-5, Example 3-6, Comparative Example 3-7, and Comparative Example 3-8, a CCFL light source having a diameter of 3.4 mm ⁇ and a length of 710 mm was used as the light source of the light source unit.
  • the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.7 mm, and six are arranged so that the distance p between the light sources is 63.0 mm.
  • a light source unit was prepared.
  • Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000) at a distance of 75 cm from the light source unit, and the average luminance value measured in the range of 20 mm ⁇ 190 mm in the center of the light source unit as luminance. did.
  • the luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ⁇ 11.8 mm from each point in the y-axis direction. Luminance unevenness was obtained.
  • the maximum standard deviation 0.005 that can allow the luminance unevenness by visual inspection is used as a boundary, and the determination criterion of the luminance unevenness is classified into two stages ( ⁇ , ⁇ ) as follows. ⁇ : S. D. ⁇ 0.005 X: 0.005 ⁇ S. D.
  • Example 3-5 As shown in FIG. 26 (a), an optical sheet having a prism array formed on the surface and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source, and further above that. DS, prism sheet (BEFIII), and reflective polarizing sheet (DBEF) were arranged in this order to form a light source unit of Example 3-5.
  • a prism made of polystyrene having a thickness of 1.5 mm, containing 500 ppm of silicone fine particles having a true specific gravity of 1.35 and a particle diameter of 2 ⁇ m inside, a light emitting surface with a pitch of 300 ⁇ m, a height of 100 ⁇ m and a rounded prism Evaluation was performed on a light source unit in which the longitudinal direction of the R prism was arranged in parallel with the longitudinal direction of the CCFL light source, in which the row (R prism) was formed (manufactured by Asahi Kasei E-Materials Co., Ltd.).
  • the said optical sheet made the surface in which the prism row
  • the diffusion sheet of the present invention has a maximum diffusion angle of 45 ° and a minimum value of 7 °, and the diffusion angle is smoothly distributed in the surface of the diffusion sheet as shown in FIG. 10C.
  • Such a diffusion sheet was disposed such that the uneven surface becomes the light exit surface.
  • the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the R prism was formed was 16.3 mm.
  • the luminance in the light source unit of Example 3-5 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 11 below.
  • Example 3-6 As shown in FIG. 26 (a), an optical sheet having a lenticular lens formed on the surface thereof and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source. DS, a prism sheet (BEFIII), and a reflective polarizing sheet (DBEF) were arranged in this order to constitute a light source unit of Example 3-6.
  • BEFIII prism sheet
  • DBEF reflective polarizing sheet
  • a lenticular lens made of polystyrene having a thickness of 1.5 mm, containing 1000 ppm of silicone fine particles having a true specific gravity of 1.35 and a particle size of 2 ⁇ m inside, and having a height of 130 ⁇ m and a pitch of 320 ⁇ m was formed on the light exit surface.
  • the product manufactured by Asahi Kasei E-Materials Co., Ltd.
  • the diffusion sheet of the present invention has a maximum diffusion angle of 30 ° and a minimum value of 0.5 °, and the diffusion angle is smoothly distributed in the surface of the diffusion sheet as shown in FIG.
  • the diffusion sheet as described above was arranged so that the uneven surface became the light exit surface.
  • the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value of this diffusion sheet is 15 °, and the diffusion angles at all measurement points distributed between the continuous diffusion angle peak value and the diffusion angle bottom value.
  • the arithmetic average value (Av2) of was 11.7 °.
  • the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the lenticular lens was formed was 18.3 mm.
  • the luminance in the light source unit of Example 3-6 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 11 below.
  • Example 3-7 The light source unit of Example 3-5 has the same configuration except that the diffusion sheet according to the light beam control unit of the present invention is not used, and the light source unit of Comparative Example 3-7 is configured.
  • the luminance in the light source unit of Comparative Example 3-7 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 11 below.
  • Example 3-8 The light source unit of Example 3-6 has the same configuration except that the diffusion sheet according to the light beam control unit of the present invention is not used, and the light source unit of Comparative Example 3-8 is configured.
  • the luminance in the light source unit of Comparative Example 3-8 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 11 below.
  • the luminance unevenness could be reduced in the light source unit having the configuration of the light beam control unit / DS / prism sheet / DBEF of the present invention shown in FIG.
  • the present invention is not limited to the above embodiment, and can be implemented with various modifications.
  • the material, arrangement, shape, and the like of the members in the above embodiment are illustrative, and can be implemented with appropriate changes.
  • the light source unit can be configured by appropriately combining the configurations shown in the first and second embodiments.
  • various modifications can be made without departing from the scope of the present invention.
  • the present invention is effective for a diffusion sheet, a light beam control unit, and a light source unit of a display device such as a liquid crystal display device.

Abstract

Provided is a diffusion sheet which can reduce uneven brightness and in which light incident upon a sheet surface at a right angle is emitted at a diffusion angle which periodically varies in a predetermined direction in a sheet surface. In a diffusion angle distribution diagram in which the abscissa represents relative positions in the sheet surface in the predetermined direction and the ordinate represents the diffusion angles at the relative positions in the sheet surface, there are a plurality of peak values of the diffusion angle and bottom values of the diffusion angle, and the arithmetic average value of the diffusion angles between the adjacent peak values and bottom values is greater than the arithmetic average value of the diffusion angles at all points distributed between the adjacent peak values and bottom values.

Description

拡散シート、光線制御ユニット及び光源ユニットDiffusion sheet, light beam control unit and light source unit
　本発明は、液晶表示装置等の背面照明（ｂａｃｋ　ｌｉｇｈｔｉｎｇ）に用いられる拡散シート、光線制御ユニット及び光源ユニットに関する。 The present invention relates to a diffusion sheet, a light beam control unit and a light source unit used for back lighting of a liquid crystal display device or the like.
　現在、液晶表示装置は、携帯電話、ＰＤＡ端末、デジタルカメラ、テレビ、パーソナルコンピュータ用ディスプレイ、ノートパソコンなどの幅広い分野で利用されている。液晶表示装置においては、例えば、液晶表示パネルの背後にバックライトユニットのような光源ユニットを配置し、この光源ユニットからの光を液晶表示パネルに供給することにより、画像を表示する。このような液晶表示装置に用いられる光源ユニットは、その表示画像を見やすくするために、液晶表示パネルに均一な光を供給するだけでなく、できるだけ多くの光を供給することが要求される。つまり、光源ユニットは、光拡散性に優れると共に高い輝度が得られるという光学特性が要求される。 Currently, liquid crystal display devices are used in a wide range of fields such as mobile phones, PDA terminals, digital cameras, televisions, personal computer displays, and notebook computers. In a liquid crystal display device, for example, a light source unit such as a backlight unit is arranged behind a liquid crystal display panel, and an image is displayed by supplying light from the light source unit to the liquid crystal display panel. The light source unit used in such a liquid crystal display device is required not only to supply uniform light to the liquid crystal display panel but also to supply as much light as possible in order to make the display image easy to see. In other words, the light source unit is required to have optical characteristics such as excellent light diffusibility and high brightness.
　従来の光源ユニットは、例えば、液晶表示パネルに入射する光の分布をパネル全体にわたって均一にするために、導光板或いは拡散板に凹凸形状を付与する手法が用いられていた。前記形状を付与する方法としては、金型を用いて樹脂を射出成形する手法や、ダイヤモンド刃によって凹凸構造をロールに加工し、それを用いて押出成形する手法がある。 In the conventional light source unit, for example, in order to make the distribution of the light incident on the liquid crystal display panel uniform over the entire panel, a method of giving an uneven shape to the light guide plate or the diffusion plate is used. As a method for imparting the shape, there are a technique of injection molding of a resin using a mold, and a technique of processing a concavo-convex structure into a roll with a diamond blade and extrusion molding using the roll.
　ここで、前記のような機械的な凹凸形成方法は多くの時間が掛かり、作製費用が高くなるという問題があった。また、前記のような凹凸形成方法では、数十μｍ程度の構造が限界であることや、形状の均一性を高めることが容易ではないという問題があった。これに対して、レーザービームのスペックルによって感光性媒体に凹凸形状を記録し、パターン転写用の金型を製造し、この金型を用いて、直下型の大型液晶表示装置用の導光板表面に凹凸を形成し、ホログラム導光板とする発明が開示されている（特許文献１　図４１）。 Here, the mechanical unevenness forming method as described above has a problem that it takes a lot of time and the production cost is high. Further, the above-described unevenness forming method has a problem that the structure of about several tens of μm is the limit and it is not easy to improve the shape uniformity. On the other hand, the concave / convex shape is recorded on the photosensitive medium by the speckle of the laser beam, a mold for pattern transfer is manufactured, and the surface of the light guide plate for the large liquid crystal display device of the direct type using this mold. An invention is disclosed in which concavo-convex portions are formed on a holographic light guide plate (Patent Document 1, FIG. 41).
特開２００１－２３４２２号公報Japanese Patent Laid-Open No. 2001-23422
　しかしながら、近年は、液晶表示装置の薄型化が進み、光源と、該光源光を拡散させるための光学シート（ホログラム導光体等）との間の距離が短くなっている。また、コスト低減及び消費電力低減のため、光源ユニットの光源数を削減する手法も用いられている。ここで、従来の光源と比較し、光源のピッチ（ｐ）と光源－光学シート間距離（ｈ）の比（ｐ／ｈ）が大きくなるほど、つまり、ｈが小さくなるほど（図２７（ａ）のｈ’）、及び／或いは、ｐが大きくなる（図２７（ｂ）のｐ’）ほど、バックライトの輝度むらが顕著になる。しかしながら、特許文献１に開示されている従来の方法では、十分に輝度むらを軽減させることができず、液晶表示装置の薄型化や、光源数の削減に対応できない。 However, in recent years, liquid crystal display devices have become thinner, and the distance between a light source and an optical sheet (such as a hologram light guide) for diffusing the light source light has become shorter. In addition, a method of reducing the number of light sources of the light source unit is also used for cost reduction and power consumption reduction. Here, as compared with the conventional light source, the larger the ratio (p / h) of the light source pitch (p) and the light source-optical sheet distance (h), that is, the smaller h is (see FIG. 27A). h ′) and / or p becomes larger (p ′ in FIG. 27B), the luminance unevenness of the backlight becomes more conspicuous. However, the conventional method disclosed in Patent Document 1 cannot sufficiently reduce luminance unevenness, and cannot cope with thinning of the liquid crystal display device and reduction in the number of light sources.
　本発明はかかる点に鑑みてなされたものであり、輝度むらを軽減させることができる拡散シート及び光線制御ユニットを提供することを目的とする。 The present invention has been made in view of such a point, and an object thereof is to provide a diffusion sheet and a light beam control unit that can reduce luminance unevenness.
　本発明の拡散シートは、シート面に垂直に光線を入射した場合の出射光の拡散角度が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置での拡散角度を縦軸にとった拡散角度分布図において、前記拡散角度のピーク値と前記拡散角度のボトム値とが複数有り、隣り合う前記ピーク値と前記ボトム値との間の拡散角度の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点における拡散角度の算術平均値より大きいことを特徴とする。 The diffusion sheet of the present invention is a diffusion sheet in which a diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface, and the predetermined direction In the diffusion angle distribution diagram in which the horizontal axis represents the relative position in the sheet surface and the vertical axis represents the diffusion angle at the relative position in the sheet surface, the peak value of the diffusion angle and the bottom value of the diffusion angle There is a plurality, and the arithmetic average value of the diffusion angles between the adjacent peak value and the bottom value is the arithmetic average value of the diffusion angles at all points distributed between the adjacent peak value and the bottom value. It is characterized by being larger.
　本発明の拡散シートは、シート面に垂直に光線を入射した場合の出射光の拡散角度が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置での拡散角度を縦軸にとった拡散角度分布図において、一つの高拡散角度領域に複数のピーク値を含むことを特徴とする。 The diffusion sheet of the present invention is a diffusion sheet in which a diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface, and the predetermined direction In the diffusion angle distribution diagram in which the horizontal axis represents the relative position within the sheet surface and the vertical axis represents the diffusion angle at the relative position within the sheet surface, a plurality of peak values are included in one high diffusion angle region. It is characterized by.
　本発明の拡散シートにおいては、前記高拡散角度領域における隣接するピーク間の拡散角度分布が直線状であることが好ましい。 In the diffusion sheet of the present invention, it is preferable that the diffusion angle distribution between adjacent peaks in the high diffusion angle region is linear.
　本発明の拡散シートにおいては、前記高拡散角度領域における隣接するピーク間の拡散角度分布が、下に凸の曲線状または曲線と直線の混合形状であることが好ましい。 In the diffusion sheet of the present invention, it is preferable that the diffusion angle distribution between adjacent peaks in the high diffusion angle region is a downward convex curve shape or a mixed shape of a curve and a straight line.
　本発明の拡散シートは、シート面に垂直に光線を入射した場合の出射光の拡散角度が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置での拡散角度を縦軸にとった拡散角度分布図において、前記拡散角度のボトム値があり、前記ボトム値を含む低拡散角度領域における拡散角度分布が、前記ボトム値を極小値とする下に凸の曲線状であることを特徴とする。 The diffusion sheet of the present invention is a diffusion sheet in which a diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface, and the predetermined direction In the diffusion angle distribution diagram in which the horizontal axis represents the relative position in the sheet surface and the vertical axis represents the diffusion angle at the relative position in the sheet surface, there is a bottom value of the diffusion angle and includes the bottom value. The diffusion angle distribution in the low diffusion angle region has a downward convex curve with the bottom value as a minimum value.
　本発明の拡散シートは、前記拡散角度のピーク値と前記拡散角度のボトム値とを交互に周期的に有し、隣り合う前記ピーク値と前記ボトム値との２点における拡散角度の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点における拡散角度の算術平均値より大きく、かつ拡散角度の分布が前記ピーク値を含み上に凸の曲線形状を有する第一の区間と、拡散角度の分布が前記ボトム値を含み下に凸の曲線形状を有する第二の区間とを有することが好ましい。 The diffusion sheet of the present invention periodically has a peak value of the diffusion angle and a bottom value of the diffusion angle alternately, and an arithmetic average value of the diffusion angles at two points of the adjacent peak value and the bottom value. Is larger than the arithmetic average value of the diffusion angles at all points distributed between the adjacent peak value and the bottom value, and the distribution of the diffusion angles includes the peak value and has an upward convex curve shape. It is preferable to have one section and a second section in which the distribution of the diffusion angle includes the bottom value and has a downward convex curve shape.
　本発明の拡散シートにおいては、前記拡散角度分布図において全領域における拡散光の拡散角度が、０．１°以上１２０°以下の範囲であることが好ましい。 In the diffusion sheet of the present invention, it is preferable that the diffusion angle of the diffused light in the entire region is in the range of 0.1 ° to 120 ° in the diffusion angle distribution diagram.
　本発明の拡散シートにおいては、前記拡散角度分布図における拡散角度の最小値が、０．１°以上４０°以下であることが好ましい。 In the diffusion sheet of the present invention, it is preferable that the minimum value of the diffusion angle in the diffusion angle distribution diagram is 0.1 ° to 40 °.
　本発明の拡散シートにおいては、前記拡散角度の最大値と最小値との差が４０°以上８０°以下であることが好ましい。 In the diffusion sheet of the present invention, the difference between the maximum value and the minimum value of the diffusion angle is preferably 40 ° or more and 80 ° or less.
　本発明の拡散シートにおいては、前前記拡散角度は、前記拡散シート面に形成された凹凸構造により生じるものであることが好ましい。 In the diffusion sheet of the present invention, it is preferable that the previous diffusion angle is generated by an uneven structure formed on the surface of the diffusion sheet.
　本発明の拡散シートは、シート面に設けられた凹凸構造のアスペクト比が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置でのアスペクト比を縦軸にとったアスペクト比分布図において、前記アスペクト比のピーク値と前記アスペクト比のボトム値とが複数有り、隣り合う前記ピーク値と前記ボトム値との間のアスペクト比の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点におけるアスペクト比の算術平均値より大きいことを特徴とする。 The diffusion sheet of the present invention is a diffusion sheet in which the aspect ratio of the concavo-convex structure provided on the sheet surface changes periodically along a predetermined direction in the sheet surface, and the in-sheet surface in the predetermined direction In the aspect ratio distribution diagram in which the relative position of the aspect ratio is taken on the horizontal axis and the aspect ratio at the relative position in the sheet surface is taken on the vertical axis, there are a plurality of peak values of the aspect ratio and bottom values of the aspect ratio. The arithmetic average value of the aspect ratio between the matching peak value and the bottom value is larger than the arithmetic average value of the aspect ratio at all points distributed between the adjacent peak value and the bottom value. And
　本発明の拡散シートは、シート面に設けられた凹凸構造のアスペクト比が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置でのアスペクト比を縦軸にとったアスペクト比分布図において、一つの高アスペクト比領域に複数のピーク値を含むことを特徴とする。 The diffusion sheet of the present invention is a diffusion sheet in which the aspect ratio of the concavo-convex structure provided on the sheet surface changes periodically along a predetermined direction in the sheet surface, and the in-sheet surface in the predetermined direction In the aspect ratio distribution diagram in which the horizontal axis is the horizontal axis and the vertical axis is the aspect ratio at the relative position in the sheet surface, a plurality of peak values are included in one high aspect ratio region.
　本発明の拡散シートにおいては、前記高アスペクト比領域における隣接するピーク間のアスペクト比分布が直線状であることが好ましい。 In the diffusion sheet of the present invention, the aspect ratio distribution between adjacent peaks in the high aspect ratio region is preferably linear.
　本発明の拡散シートにおいては、前記高アスペクト比領域における隣接するピーク間のアスペクト比分布が、下に凸の曲線状または曲線と直線の混合形状であることが好ましい。 In the diffusion sheet of the present invention, it is preferable that the aspect ratio distribution between adjacent peaks in the high aspect ratio region is a downwardly convex curve shape or a mixed shape of a curve and a straight line.
　本発明の拡散シートは、シート面に設けられた凹凸構造のアスペクト比が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置でのアスペクト比を縦軸にとったアスペクト比分布図において、前記アスペクト比のボトム値があり、前記ボトム値を含む低アスペクト比領域におけるアスペクト比分布が、前記ボトム値を極小値とする下に凸の曲線状であることを特徴とする。 The diffusion sheet of the present invention is a diffusion sheet in which the aspect ratio of the concavo-convex structure provided on the sheet surface changes periodically along a predetermined direction in the sheet surface, and the in-sheet surface in the predetermined direction In an aspect ratio distribution diagram in which the horizontal axis is the horizontal axis and the aspect ratio at the relative position in the sheet plane is the vertical axis, there is a bottom value of the aspect ratio in a low aspect ratio region including the bottom value. The aspect ratio distribution has a downward convex curve with the bottom value as a minimum value.
　本発明の拡散シートは、前記アスペクト比分布のピーク値と前記アスペクト比分布のボトム値とを交互に周期的に有し、隣り合う前記ピーク値と前記ボトム値との２点におけるアスペクト比分布の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点におけるアスペクト比分布の算術平均値より大きく、かつアスペクト比分布が前記ピーク値を含み上に凸の曲線形状を有する第一の区間と、アスペクト比分布が前記ボトム値を含み下に凸の曲線形状を有する第二の区間とを有することが好ましい。 The diffusion sheet of the present invention has the peak value of the aspect ratio distribution and the bottom value of the aspect ratio distribution alternately and periodically, and the aspect ratio distribution at two points of the adjacent peak value and the bottom value. The arithmetic average value is larger than the arithmetic average value of the aspect ratio distribution at all points distributed between the adjacent peak value and the bottom value, and the aspect ratio distribution includes the peak value and has an upwardly convex curve shape It is preferable that the first section has a second section in which the aspect ratio distribution includes the bottom value and has a downward convex curve shape.
　本発明の拡散シートにおいては、前記凹凸構造の高さが変化することによって、前記アスペクト比が変化する形状を有することが好ましい。 The diffusion sheet of the present invention preferably has a shape in which the aspect ratio changes as the height of the concavo-convex structure changes.
　本発明の拡散シートにおいては、前記凹凸構造のピッチが変化することによって、前記アスペクト比が変化する形状を有することが好ましい。 The diffusion sheet of the present invention preferably has a shape in which the aspect ratio changes as the pitch of the uneven structure changes.
　本発明の拡散シートにおいては、前記凹凸構造が干渉露光によるスペックルパターンを用いて形成された凹凸構造であることが好ましい。 In the diffusion sheet of the present invention, the uneven structure is preferably an uneven structure formed using a speckle pattern by interference exposure.
　本発明の光源ユニットは、２つ以上の光源と、前記光源の上方に配設される上記拡散シートと、を備えることが好ましい。 The light source unit of the present invention preferably includes two or more light sources and the diffusion sheet disposed above the light sources.
　本発明の光源ユニットは、少なくとも二つの光源と、前記光源の下方に配設され、前記光源からの光を反射させる反射シートと、前記光源の上方に配設される上記拡散シートとを具備することが好ましい。 The light source unit of the present invention includes at least two light sources, a reflection sheet that is disposed below the light source and reflects light from the light source, and the diffusion sheet that is disposed above the light source. It is preferable.
　本発明の光源ユニットは、少なくとも二つの光源と、前記光源の下方に配設され、前記光源からの光を反射させる反射シートと、前記光源の上方に配設され、前記光源からの光を拡散させる拡散板と、前記拡散板の上方に配設される上記拡散シートとを具備することが好ましい。 The light source unit of the present invention includes at least two light sources, a reflection sheet that is disposed below the light source and reflects light from the light source, and is disposed above the light source and diffuses light from the light source. It is preferable that the diffusion plate to be disposed and the diffusion sheet disposed above the diffusion plate.
　本発明の光源ユニットにおいては、上記光源が線状光源であることが好ましい。 In the light source unit of the present invention, the light source is preferably a linear light source.
　本発明の光源ユニットにおいては、上記光源が点状光源であることが好ましい。 In the light source unit of the present invention, the light source is preferably a point light source.
　本発明の光源ユニットにおいては、前記拡散シートの拡散角度分布の周期と、前記拡散シートの入光面における照度分布の周期とが略等しいことが好ましい。 In the light source unit of the present invention, it is preferable that the period of the diffusion angle distribution of the diffusion sheet and the period of the illuminance distribution on the light incident surface of the diffusion sheet are substantially equal.
　本発明の光源ユニットにおいては、前記拡散シートと光源の間に配置され、内部に拡散剤を含有する拡散板と、前記光源の下方に配置される反射シートと、を備えることが好ましい。 The light source unit of the present invention preferably includes a diffusion plate disposed between the diffusion sheet and the light source and containing a diffusing agent therein, and a reflection sheet disposed below the light source.
　本発明の光源ユニットにおいては、前記拡散シートの上方に配置されるレンズシートを備えることが好ましい。 In the light source unit of the present invention, it is preferable to include a lens sheet disposed above the diffusion sheet.
　本発明の光源ユニットにおいては、前記拡散シートの上方に配置されるプリズムシートを備えることが好ましい。 The light source unit according to the present invention preferably includes a prism sheet disposed above the diffusion sheet.
　本発明の光源ユニットにおいては、前記拡散シート上方に配置される反射型偏光シートを備えることが好ましい。 The light source unit of the present invention preferably includes a reflective polarizing sheet disposed above the diffusion sheet.
　本発明の光源ユニットにおいては、表面に複数のレンズにより構成されたレンズ部が形成された光学シートを有し、前記光学シートの表面側に、前記拡散シートが配置されていることが好ましい。 The light source unit of the present invention preferably has an optical sheet having a lens portion formed of a plurality of lenses on the surface, and the diffusion sheet is disposed on the surface side of the optical sheet.
　本発明の光源ユニットにおいては、前記光学シートの前記レンズ部が、単位レンズを複数配列することにより構成されており、かつ前記単位レンズの底面形状が異方性を有する形状であることが好ましい。 In the light source unit of the present invention, it is preferable that the lens portion of the optical sheet is configured by arranging a plurality of unit lenses, and the bottom shape of the unit lens is an anisotropic shape.
　本発明の光源ユニットにおいては、前記単位レンズの底面形状が、楕円形又は長方形であることが好ましい。 In the light source unit of the present invention, it is preferable that the bottom shape of the unit lens is an ellipse or a rectangle.
　本発明の光源ユニットにおいては、前記単位レンズが、レンチキュラーレンズ又はプリズム条列であることが好ましい。 In the light source unit of the present invention, the unit lens is preferably a lenticular lens or a prism array.
　本発明の光源ユニットにおいては、前記光学シートの前記レンズ部が、単位レンズを複数配列することにより構成されており、かつ前記単位レンズの底面形状が等方性を有する形状であることが好ましい。 In the light source unit of the present invention, it is preferable that the lens portion of the optical sheet is formed by arranging a plurality of unit lenses, and that the shape of the bottom surface of the unit lens is isotropic.
　本発明の光源ユニットにおいては、前記単位レンズの底面形状が、円形、正方形、正６角形であることが好ましい。 In the light source unit of the present invention, it is preferable that the bottom shape of the unit lens is a circle, a square, or a regular hexagon.
　本発明の光源ユニットにおいては、前記単位レンズが、マイクロレンズ又はマイクロプリズムであることが好ましい。 In the light source unit of the present invention, the unit lens is preferably a microlens or a microprism.
　本発明の光源ユニットにおいては、前記光学シートの前記レンズ部が、底面形状が異方性を有する形状のレンズと、等方性を有する形状のレンズとを配列することにより構成されていることが好ましい。 In the light source unit of the present invention, the lens portion of the optical sheet may be configured by arranging a lens having a shape whose bottom surface has anisotropy and a lens having an isotropic shape. preferable.
　本発明の液晶表示装置は、液晶表示パネルと、前記液晶表示パネルに光を供給する上記に記載の光源ユニットと、を備えることが好ましい。 The liquid crystal display device of the present invention preferably includes a liquid crystal display panel and the light source unit described above that supplies light to the liquid crystal display panel.
　本発明の光線制御ユニットは、光源からの光を入光する入光面と、前記入光面から入光した光を出光する出光面と、を有し、表面に複数のレンズにより構成されたレンズ部が形成された光学シートと、前記光学シートのシート面に垂直に光線を入射した場合に、前記シート面内の所定の方向に沿って拡散角度が周期的に変化する拡散シートと、を備えたことを特徴とする。 The light beam control unit of the present invention has a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface, and is configured by a plurality of lenses on the surface. An optical sheet on which a lens portion is formed, and a diffusion sheet whose diffusion angle periodically changes along a predetermined direction in the sheet surface when light rays are incident on the sheet surface of the optical sheet perpendicularly. It is characterized by having.
　本発明の光線制御ユニットは、光源からの光を入光する入光面と、前記入光面から入光した光を出光する出光面と、を有し、表面に複数のレンズにより構成されたレンズ部が形成された光学シートと、前記光学シートのシート面に垂直に光線を入射した場合に、前記シート面内の所定の方向に沿ってシート面に設けられた凹凸構造のアスペクト比が周期的に変化する拡散シートと、を備えたことを特徴とする。 The light beam control unit of the present invention has a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface, and is configured by a plurality of lenses on the surface. An optical sheet having a lens portion and an aspect ratio of the concavo-convex structure provided on the sheet surface along a predetermined direction in the sheet surface when a light beam is incident on the sheet surface of the optical sheet perpendicularly. And a diffusion sheet that changes periodically.
　本発明の光線制御ユニットにおいては、前記光学シートの前記表面側に、前記拡散シートが配置されていることが好ましい。 In the light beam control unit of the present invention, it is preferable that the diffusion sheet is disposed on the surface side of the optical sheet.
　本発明の光線制御ユニットにおいては、前記光学シートの前記レンズ部が、単位レンズを複数配列することにより構成されており、かつ前記単位レンズの底面形状が異方性を有する形状であることが好ましい。 In the light beam control unit of the present invention, the lens portion of the optical sheet is preferably configured by arranging a plurality of unit lenses, and the bottom shape of the unit lens is preferably an anisotropic shape. .
　本発明の光線制御ユニットにおいては、前記単位レンズの底面形状が、楕円形又は長方形であることが好ましい。 In the light beam control unit of the present invention, it is preferable that the bottom shape of the unit lens is an ellipse or a rectangle.
　本発明の光線制御ユニットにおいては、前記単位レンズが、レンチキュラーレンズ又はプリズム条列であることが好ましい。 In the light beam control unit of the present invention, the unit lens is preferably a lenticular lens or a prism array.
　本発明の光線制御ユニットにおいては、前記光学シートの前記レンズ部が、単位レンズを複数配列することにより構成されており、かつ前記単位レンズの底面形状が等方性を有する形状であることが好ましい。 In the light beam control unit of the present invention, the lens portion of the optical sheet is preferably configured by arranging a plurality of unit lenses, and the bottom shape of the unit lens is preferably isotropic. .
　本発明の光線制御ユニットにおいては、前記単位レンズの底面形状が、円形、正方形、正６角形であることが好ましい。 In the light beam control unit of the present invention, it is preferable that the bottom shape of the unit lens is a circle, a square, or a regular hexagon.
　本発明の光線制御ユニットにおいては、前記単位レンズが、マイクロレンズ又はマイクロプリズムであることが好ましい。 In the light beam control unit of the present invention, the unit lens is preferably a microlens or a microprism.
　本発明の光線制御ユニットにおいては、前記光学シートの前記レンズ部が、底面形状が異方性を有する形状のレンズと、等方性を有する形状のレンズとを配列することにより構成されていることが好ましい。 In the light beam control unit of the present invention, the lens portion of the optical sheet is configured by arranging a lens having a shape whose bottom surface has anisotropy and a lens having an isotropic shape. Is preferred.
　本発明の光線制御ユニットにおいては、前記拡散シートの拡散角度が、０．１°以上１２０°以下の範囲内であることが好ましい。 In the light beam control unit of the present invention, it is preferable that the diffusion angle of the diffusion sheet is in the range of 0.1 ° to 120 °.
　本発明の光線制御ユニットにおいては、前記拡散角度は、前記拡散シートの表面に形成された凹凸構造により生じることが好ましい。 In the light beam control unit of the present invention, it is preferable that the diffusion angle is generated by an uneven structure formed on the surface of the diffusion sheet.
　本発明の光線制御ユニットにおいては、前記凹凸構造が干渉露光によるスペックルパターンを用いて形成されていることが好ましい。 In the light beam control unit of the present invention, it is preferable that the concavo-convex structure is formed using a speckle pattern by interference exposure.
　本発明の光源ユニットは、２つ以上の光源と、前記光源の上方に配設される上記光線制御ユニットと、を備えることを特徴とする。 The light source unit of the present invention includes two or more light sources and the light beam control unit disposed above the light sources.
　本発明の光源ユニットにおいては、前記拡散シートの拡散角度分布の周期と、前記拡散シートの入光面における照度分布の周期とを略等しくしたことが好ましい。 In the light source unit of the present invention, it is preferable that the period of the diffusion angle distribution of the diffusion sheet is substantially equal to the period of the illuminance distribution on the light incident surface of the diffusion sheet.
　本発明の光源ユニットにおいては、前記光源の下方に配置された反射シートを備えることが好ましい。 In the light source unit of the present invention, it is preferable to include a reflective sheet disposed below the light source.
　本発明の光源ユニットにおいては、前記拡散シート上方に配置されるプリズムシートを備えることが好ましい。 The light source unit according to the present invention preferably includes a prism sheet disposed above the diffusion sheet.
　本発明の光源ユニットにおいては、前記拡散シート上方に配置される反射型偏光シートを備えることが好ましい。 The light source unit of the present invention preferably includes a reflective polarizing sheet disposed above the diffusion sheet.
　本発明の液晶表示装置は、液晶表示パネルと、前記液晶表示パネルに光を供給する上記光源ユニットと、を備えることを特徴とする。 The liquid crystal display device of the present invention includes a liquid crystal display panel and the light source unit that supplies light to the liquid crystal display panel.
　本発明の拡散シートによれば、輝度むらを軽減させることができる拡散シートを実現することができる。 According to the diffusion sheet of the present invention, it is possible to realize a diffusion sheet that can reduce uneven brightness.
　本発明の光線制御ユニットによれば、光源からの光を入光する入光面と、前記入光面から入光した光を出光する出光面と、を有し、表面に複数のレンズにより構成されたレンズ部が形成された光学シートと、前記光学シートのシート面に垂直に光線を入射した場合に、前記シート面内の所定の方向に沿って拡散角度が周期的に変化する拡散シートと、を備え、前記拡散シートが該光学シートの前記レンズが形成された面側に配置されるので、２枚のシートが有する拡散性の相乗効果により、光源と光源との間の領域に光を供給することが可能となり、輝度むらを少なくすることができる。 According to the light beam control unit of the present invention, the light control unit has a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface, and is configured by a plurality of lenses on the surface. An optical sheet on which the lens unit is formed, and a diffusion sheet whose diffusion angle periodically changes along a predetermined direction in the sheet surface when a light beam is incident on the sheet surface of the optical sheet perpendicularly. And the diffusion sheet is disposed on the surface side of the optical sheet on which the lens is formed, so that light is emitted to a region between the light sources by the synergistic effect of diffusibility of the two sheets. Thus, it is possible to reduce the luminance unevenness.
本発明の実施の形態１に係る拡散シートにおける拡散角度（アスペクト比）の分布を示す図である。It is a figure which shows distribution of the diffusion angle (aspect ratio) in the diffusion sheet which concerns on Embodiment 1 of this invention. （ａ），（ｂ）は、本発明の実施の形態１に係る光源の投影領域と光源の間の投影領域を示す図である。(A), (b) is a figure which shows the projection area | region between the projection area | region of the light source and light source which concern on Embodiment 1 of this invention. （ａ）～（ｆ）は、本発明の実施の形態１に係る拡散シートの拡散角度の、シート面内の相対位置に対する分布を示す図である。(A)-(f) is a figure which shows distribution with respect to the relative position in a sheet | seat surface of the diffusion angle of the diffusion sheet which concerns on Embodiment 1 of this invention. （ａ）～（ｆ）は、本発明の実施の形態１に係る拡散シートのアスペクト比の、シート面内の相対位置に対する分布を示す図である。(A)-(f) is a figure which shows distribution with respect to the relative position in the sheet surface of the aspect-ratio of the diffusion sheet which concerns on Embodiment 1 of this invention. 本発明の実施の形態１、２に係る拡散シートを正面から見た場合の模式図である。It is a schematic diagram at the time of seeing the diffusion sheet which concerns on Embodiment 1, 2 of this invention from the front. 本発明の実施の形態１、２に係る拡散シートを正面から見た場合の模式図である。It is a schematic diagram at the time of seeing the diffusion sheet which concerns on Embodiment 1, 2 of this invention from the front. 本発明の実施の形態１、２に係る拡散シートを正面から見た場合の模式図である。It is a schematic diagram at the time of seeing the diffusion sheet which concerns on Embodiment 1, 2 of this invention from the front. （ａ），（ｂ）は、本発明の実施の形態１に係る拡散シートにおける、拡散角度の定義を示す図である。(A), (b) is a figure which shows the definition of the diffusion angle in the diffusion sheet which concerns on Embodiment 1 of this invention. 本発明の実施の形態１に係る拡散シートにおける、アスペクト比の定義を示す図である。It is a figure which shows the definition of the aspect ratio in the diffusion sheet which concerns on Embodiment 1 of this invention. （ａ）～（ｆ）は、実施の形態２で示す光線制御ユニットで用いられる拡散シートにおける拡散角度の、シート面内の相対位置に対する分布を示す図である。(A)-(f) is a figure which shows distribution with respect to the relative position in a sheet | seat surface of the diffusion angle in the diffusion sheet used with the light beam control unit shown in Embodiment 2. FIG. （ａ）～（ｆ）は、実施の形態２で示す光線制御ユニットで用いられる拡散シートにおけるアスペクト比の、シート面内の相対位置に対する分布を示す図である。(A)-(f) is a figure which shows distribution with respect to the relative position in a sheet | seat surface of the aspect-ratio in the diffusion sheet used with the light beam control unit shown in Embodiment 2. FIG. 本発明の実施の形態２に係る光線制御ユニットの構成を示す図である。It is a figure which shows the structure of the light beam control unit which concerns on Embodiment 2 of this invention. 本発明の実施の形態２に係る光線制御ユニットの断面構造を示す図である。It is a figure which shows the cross-section of the light beam control unit which concerns on Embodiment 2 of this invention. （ａ）～（ｆ）は、本発明の実施の形態２に係る光線制御ユニットに用いられる光学シートを正面から見た場合の模式図である。(A)-(f) is a schematic diagram when the optical sheet used for the light beam control unit concerning Embodiment 2 of this invention is seen from the front. （ａ）～（ｃ）は、本発明の実施の形態２に係る光線制御ユニットに用いられる光学シートを斜め上方から見た場合の模式図である。(A)-(c) is a schematic diagram at the time of seeing the optical sheet used for the light beam control unit concerning Embodiment 2 of this invention from diagonally upward. （ａ）～（ｅ）は、本発明の実施の形態２に係る光線制御ユニットに用いられる光学シートを正面から見た場合の模式図である。(A)-(e) is a schematic diagram when the optical sheet used for the light beam control unit according to Embodiment 2 of the present invention is viewed from the front. （ａ）～（ｅ）は、本発明の実施２の形態に係る光線制御ユニットに用いられる光学シートを斜め上方から見た場合の模式図である。(A)-(e) is a schematic diagram when the optical sheet used for the light beam control unit according to the second embodiment of the present invention is viewed obliquely from above. （ａ）～（ｅ）は、本発明の実施の形態２に係る光線制御ユニットに用いられる光学シートを正面から見た場合の模式図である。(A)-(e) is a schematic diagram when the optical sheet used for the light beam control unit according to Embodiment 2 of the present invention is viewed from the front. （ａ），（ｂ）は、本発明の実施の形態３に係る光源ユニットの構成を示す図である。(A), (b) is a figure which shows the structure of the light source unit which concerns on Embodiment 3 of this invention. （ａ），（ｂ）は、本発明の実施の形態３に係る光源ユニットの構成を示す図である。(A), (b) is a figure which shows the structure of the light source unit which concerns on Embodiment 3 of this invention. （ａ），（ｂ）は、本発明の実施の形態３に係る光源ユニットの構成を示す図である。(A), (b) is a figure which shows the structure of the light source unit which concerns on Embodiment 3 of this invention. 本発明の実施の形態３に係る拡散シートにおける拡散角度の、シート面内の相対位置に対する分布を示す図である。It is a figure which shows distribution with respect to the relative position in a sheet | seat surface of the diffusion angle in the diffusion sheet which concerns on Embodiment 3 of this invention. （ａ）～（ｃ）は、本発明の実施の形態３に係る光源ユニットの構成の他の例を示す図である。(A)-(c) is a figure which shows the other example of a structure of the light source unit which concerns on Embodiment 3 of this invention. 本発明の実施の形態３に係る光源ユニットの構成の他の例を示す図である。It is a figure which shows the other example of a structure of the light source unit which concerns on Embodiment 3 of this invention. （ａ）～（ｄ）は、本発明の実施の形態３に係る光源ユニットの構成の他の例を示す図である。(A)-(d) is a figure which shows the other example of a structure of the light source unit which concerns on Embodiment 3 of this invention. （ａ），（ｂ）は、本発明の実施の形態３に係る光源ユニットの構成の他の例を示す図である。(A), (b) is a figure which shows the other example of a structure of the light source unit which concerns on Embodiment 3 of this invention. （ａ），（ｂ）は、本発明の実施の形態３に係る光源ユニットの断面構造を示す図である。(A), (b) is a figure which shows the cross-section of the light source unit which concerns on Embodiment 3 of this invention. （ａ）～（ｃ）は、本発明の実施例において、拡散シートの拡散角度と光源距離の関係を示す図である。(A)-(c) is a figure which shows the relationship between the diffusion angle of a diffusion sheet, and light source distance in the Example of this invention. （ａ），（ｂ）は、本発明の実施例において、拡散シートの拡散角度と光源距離の関係を示す図である。(A), (b) is a figure which shows the relationship between the diffusion angle of a diffusion sheet, and light source distance in the Example of this invention. （ａ）～（ｃ）は、本発明の実施例に用いたＬＥＤ光源の配置を示すものである。(A)-(c) shows arrangement | positioning of the LED light source used for the Example of this invention. （ａ）～（ｃ）は、本発明の実施例において、拡散シートの拡散角度と光源距離の関係を示す図である。(A)-(c) is a figure which shows the relationship between the diffusion angle of a diffusion sheet, and light source distance in the Example of this invention.
　以下、本発明の実施の形態について、添付図面を参照して詳細に説明する。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
（実施の形態１）
　実施の形態１では、本発明の拡散シートの一例について説明する。 (Embodiment 1)
In Embodiment 1, an example of the diffusion sheet of the present invention will be described.
　図２（ａ），（ｂ）は、光源の投影領域と光源の間の投影領域を示したものである。光源は、複数（少なくとも２つ）配設されている。光源としては、図２（ａ）に示すように、冷陰極管（ＣＣＦＬ）１０１などの線光源や、図２（ｂ）に示すように、ＬＥＤ（発光ダイオード）１０２、レーザーなどの点光源を用いることができる。図２（ａ），（ｂ）において、参照符号１０３は光源直上の投影領域を示し、参照符号１０４は光源間の投影領域を示す。なお、図２（ａ），（ｂ）では、全体の領域を光源直上の投影領域と、光源間の投影領域との２つに分割している例を示しているが、光源直上の投影領域、光源間の投影領域以外の領域を設けるように分割してもよい。また、光源間の投影領域は、光源直上の投影領域に隣接していなくてもよく、近接する光源の中間に位置する領域を含んでいればよい。 2 (a) and 2 (b) show the projection area between the light source and the projection area between the light sources. A plurality (at least two) of light sources are arranged. As a light source, a line light source such as a cold cathode fluorescent lamp (CCFL) 101 as shown in FIG. 2A, or a point light source such as an LED (light emitting diode) 102 or a laser as shown in FIG. 2B. Can be used. 2A and 2B, reference numeral 103 indicates a projection area immediately above the light source, and reference numeral 104 indicates a projection area between the light sources. FIGS. 2A and 2B show an example in which the entire area is divided into a projection area immediately above the light source and a projection area between the light sources. Further, it may be divided so as to provide an area other than the projection area between the light sources. In addition, the projection area between the light sources may not be adjacent to the projection area immediately above the light source, and may include an area located in the middle of the adjacent light sources.
　本実施の形態１で示す拡散シートは、シート面に垂直に光線を入射した場合の出射光の拡散角度が前記シート面内の所定の方向に沿って周期的に変化することを特徴とする。このシートを光源の上方に配設する場合、シートの拡散角度の周期を、光源直上領域と光源間領域とからなる投影領域周期に合わせることが好ましい。これにより、輝度ムラを低減することができる。 The diffusion sheet shown in the first embodiment is characterized in that the diffusion angle of emitted light when a light beam is incident perpendicularly to the sheet surface periodically changes along a predetermined direction in the sheet surface. When this sheet is disposed above the light source, it is preferable to adjust the period of the diffusion angle of the sheet to the projection area period composed of the region directly above the light source and the region between the light sources. Thereby, luminance unevenness can be reduced.
　本発明において、「拡散角度」とは、透過光強度がピーク強度の半分に減衰する角（半値角）の２倍の角度（ＦＷＨＭ：Full Width Half Maximum）をいう（図８（ａ）参照）。この拡散角度は、例えば、Photon（株）社製のPhotonで、拡散シートの凹凸面の法線方向から、凹凸面側より入射した光に対する透過光強度の角度分布を測定することによって求めることができる。ここで、拡散シートの法線方向とは、図８（ｂ）に示す方向を指す。 In the present invention, the “diffusion angle” refers to an angle (FWHM: Full Width Half Maximum) that is twice the angle (half-value angle) at which the transmitted light intensity attenuates to half of the peak intensity (see FIG. 8A). . This diffusion angle can be obtained, for example, by measuring the angular distribution of transmitted light intensity with respect to light incident from the uneven surface side from the normal direction of the uneven surface of the diffusion sheet, with Photon manufactured by Photon Co., Ltd. it can. Here, the normal direction of the diffusion sheet refers to the direction shown in FIG.
　また、本発明の拡散シートとしては、測定方向によらず、ほぼ同じ拡散角度が得られる等方拡散シートと、測定方向によって、拡散角度が異なる異方拡散シートの両方を用いることができる。異方拡散シートとは、例えば、直交する２つの方向で拡散角度を測定した場合に、拡散角度が異なるような拡散シートである。 Also, as the diffusion sheet of the present invention, both an isotropic diffusion sheet capable of obtaining substantially the same diffusion angle regardless of the measurement direction and an anisotropic diffusion sheet having a different diffusion angle depending on the measurement direction can be used. An anisotropic diffusion sheet is, for example, a diffusion sheet having different diffusion angles when the diffusion angles are measured in two orthogonal directions.
　図１は、実施の形態１で示す拡散シートにおける拡散角度（又はアスペクト比）の分布を示す図である。この拡散シートは、シート面に垂直に光線を入射した場合の出射光の拡散角度（又はアスペクト比）が前記シート面内の所定の方向に沿って周期的に変化するものである。図１に示す拡散角度（又はアスペクト比）分布図においては、シート面内の所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置での拡散角度（又はアスペクト比）を縦軸にとっている。実施の形態１に係る拡散シートにおいては、拡散角度（又はアスペクト比）のピーク値と拡散角度（又はアスペクト比）のボトム値とが複数有る（図１においては１つ示している）。ピーク値とは、拡散角度（又はアスペクト比）の分布の１周期の中で最も高い拡散角度（又はアスペクト比）の値をいい、ボトム値とは、拡散角度（又はアスペクト比）の分布の１周期の中で最も低い拡散角度（又はアスペクト比）の値をいう。 FIG. 1 is a diagram showing a distribution of diffusion angles (or aspect ratios) in the diffusion sheet shown in the first embodiment. In this diffusion sheet, the diffusion angle (or aspect ratio) of emitted light when a light beam is incident on the sheet surface perpendicularly changes periodically along a predetermined direction in the sheet surface. In the diffusion angle (or aspect ratio) distribution chart shown in FIG. 1, the horizontal axis indicates the relative position within the sheet surface in a predetermined direction within the sheet surface, and the diffusion angle (or aspect at the relative position within the sheet surface). Ratio) on the vertical axis. The diffusion sheet according to Embodiment 1 has a plurality of diffusion angle (or aspect ratio) peak values and diffusion angle (or aspect ratio) bottom values (one is shown in FIG. 1). The peak value refers to the value of the highest diffusion angle (or aspect ratio) in one period of the distribution of the diffusion angle (or aspect ratio), and the bottom value refers to 1 of the distribution of the diffusion angle (or aspect ratio). The value of the lowest diffusion angle (or aspect ratio) in the period.
　実施の形態１に示す拡散シートでは、このような拡散角度分布図において、隣り合うピーク値とボトム値との間の拡散角度の算術平均値が、前記隣り合うピーク値とボトム値との間に分布する全点における拡散角度の算術平均値より大きいことを特徴とする。ここで述べる「全点」とは、測定点の全てを意味するものである。 In the diffusion sheet shown in Embodiment 1, in such a diffusion angle distribution diagram, the arithmetic average value of the diffusion angles between adjacent peak values and bottom values is between the adjacent peak values and bottom values. It is characterized by being larger than the arithmetic average value of the diffusion angles at all the distributed points. The “all points” described here mean all the measurement points.
　拡散角度の変化は、隣り合うピーク値とボトム値との算術平均値が、隣り合うピーク値とボトム値との間に分布する拡散角度の算術平均値より大きければ厳密に直線状、曲線状、階段状でなくてもよく、拡散角度の測定バラツキ等により、直線状、曲線状、階段状から若干はずれた形状や、直線と曲線の混合形状であってもよい。光源直上領域から光源間領域へ推移する場合、その位置に対する入光角度は直線的に大きくなっていく。入光角度が大きいほど拡散シートより下へ反射される光や拡散シートの法線方向に対して斜めに抜けてゆく光が大きくなっていくことを考慮すると、光源上領域から光源間領域へ推移するにつれて拡散すべき光の量は直線的ではなく、それ以上に大きく減衰する。つまり、隣り合うピーク値とボトム値との算術平均値が、隣り合うピーク値とボトム値との間に分布する拡散角度の算術平均値より大きい拡散シートであれば、拡散すべき光の減衰に合わせて輝度ムラを低減することが可能となる。図３（ａ）～図３（ｆ）に、拡散角度が直線状、曲線状、直線と曲線の混合形状に変化している拡散シートの例を示す。 Changes in the diffusion angle are strictly linear, curved if the arithmetic average value of the adjacent peak value and the bottom value is greater than the arithmetic average value of the diffusion angle distributed between the adjacent peak value and the bottom value, The shape may not be stepped, and may be a straight shape, a curved shape, a shape slightly deviated from the stepped shape, or a mixed shape of a straight line and a curved line due to variation in measurement of the diffusion angle. When transitioning from the region directly above the light source to the region between the light sources, the light incident angle with respect to that position increases linearly. Considering that the light reflected below the diffuser sheet and the light that passes obliquely with respect to the normal direction of the diffuser sheet increase as the incident angle increases, the transition from the upper light source region to the inter-light source region As it does so, the amount of light to be diffused is not linear and attenuates much more. In other words, if the diffusion sheet is larger than the arithmetic average value of the diffusion angles distributed between the adjacent peak value and the bottom value, it will attenuate the light to be diffused. In addition, luminance unevenness can be reduced. FIGS. 3A to 3F show examples of the diffusion sheet in which the diffusion angle is changed to a linear shape, a curved shape, or a mixed shape of a straight line and a curved line.
　シート内の各領域における拡散角度は、相対的に拡散角度が高い領域を光源直上に配置してもよく、相対的に拡散角度が低い領域を光源直上に配置してもよい。また、各領域間の拡散角度はなめらかに変化することが好ましい。特に、高拡散角度領域に連続する複数のピーク値を含む形状があることが輝度むら低減の観点から好ましく、その形状は直線状又は下に凸の曲線状又は直線と下に凸の曲線の混合形状であることが好ましい（図３（ｄ），（ｆ））。このようなパターンは光源が線光源の場合、特に効果的である。また、拡散角度のボトム値があり、前記ボトム値を含む低拡散角度領域における拡散角度分布が、前記ボトム値を極小値とする下に凸の曲線状であるものも輝度むら低減の観点から好ましい（図３（ａ）～（ｅ））。図３（ｃ）は拡散角度の分布が前記ピーク値を含み上に凸の曲線形状を有する第一の区間と、拡散角度の分布が前記ボトム値を含み下に凸の曲線形状を有する第二の区間とを有しているが、このようなパターンは光源が点光源である場合、特に効果的である。 As for the diffusion angle in each region in the sheet, a region having a relatively high diffusion angle may be disposed immediately above the light source, and a region having a relatively low diffusion angle may be disposed directly above the light source. Moreover, it is preferable that the diffusion angle between each area | region changes smoothly. In particular, a shape including a plurality of continuous peak values in the high diffusion angle region is preferable from the viewpoint of reducing luminance unevenness, and the shape is a straight line or a downwardly convex curve, or a mixture of a straight line and a downwardly convex curve. The shape is preferable (FIGS. 3D and 3F). Such a pattern is particularly effective when the light source is a linear light source. Further, there is a bottom value of the diffusion angle, and the diffusion angle distribution in the low diffusion angle region including the bottom value is preferably a downward convex curve with the bottom value being the minimum value from the viewpoint of reducing luminance unevenness. (FIGS. 3A to 3E). FIG. 3C shows a first section in which the distribution of the diffusion angle includes the peak value and has a convex curve shape, and a second section in which the distribution of the diffusion angle includes the bottom value and has a convex curve shape. Such a pattern is particularly effective when the light source is a point light source.
　ここで、高拡散角度領域とは、ピーク値の最大値とボトム値の最小値の算術平均値以上の角度領域とし、低拡散角度領とは、ピーク値の最大値とボトム値の最小値の算術平均値以下の角度領域とする。本発明におけるピーク値とボトム値から算術平均値は、上記定義に基づく拡散角度の分布を用いて算出するものとする。なお、一周期の中で、ピーク値、ボトム値は１つとは限らず、同一の値が複数存在していてもよい。例えば、図１では、一つの高拡散角度領域に複数（２つ）のピーク値が存在している。 Here, the high diffusion angle region is an angle region that is equal to or greater than the arithmetic average value of the maximum value of the peak value and the minimum value of the bottom value, and the low diffusion angle region is the value of the maximum value of the peak value and the minimum value of the bottom value. The angle region is less than the arithmetic average value. The arithmetic average value is calculated from the peak value and the bottom value in the present invention using the distribution of diffusion angles based on the above definition. In one cycle, the peak value and the bottom value are not limited to one, and a plurality of the same values may exist. For example, in FIG. 1, there are a plurality (two) of peak values in one high diffusion angle region.
　また、隣り合うピーク値とボトム値との間に分布する拡散角度とは、図１の破線区間部分に存在する拡散角度をいうものとする。すなわち、ピーク値が複数存在する場合、隣り合うボトム値に対応する位置とピーク値に対応する位置との間の区間内に存在する拡散角度をいうものとする。 Further, the diffusion angle distributed between adjacent peak values and bottom values refers to the diffusion angle existing in the broken line section of FIG. That is, when there are a plurality of peak values, it means the diffusion angle existing in the section between the position corresponding to the adjacent bottom value and the position corresponding to the peak value.
　また、「周期的に」変化するとは、繰り返されたパターン同士を比較して、同じ繰り返しに相当するピーク値及びピーク値を与える周期の開始点からの変位、並びに、ボトム値及びボトム値を与える周期の開始点からの変位が、それぞれ、全繰り返しパターンの平均値の±１５％以内（好ましくは１０％以内、より好ましくは５％以内）の範囲内にあれば、周期的に変化しているものとする。上記の周期性を示す方向は、拡散シート面内に少なくとも一つあれば良く、拡散シート面について拡散角度の分布を作成することにより特定することができる。本発明においては、繰り返された複数のピーク値の拡散角度は、測定された全てのピーク値の拡散角度の差が５°以内となることが好ましく、３°以内がより好ましく、２°以内であることが最も好ましい。ボトム値についても同様である。 In addition, “periodically” means that the repeated patterns are compared with each other, and the peak value corresponding to the same repetition and the displacement from the start point of the period giving the peak value, and the bottom value and the bottom value are given. If the displacement from the starting point of the cycle is within a range of ± 15% (preferably within 10%, more preferably within 5%) of the average value of all the repeated patterns, it periodically changes. Shall. The direction indicating the periodicity may be at least one in the diffusion sheet surface, and can be specified by creating a distribution of diffusion angles on the diffusion sheet surface. In the present invention, the diffusion angle of a plurality of repeated peak values is preferably such that the difference in the diffusion angles of all measured peak values is within 5 °, more preferably within 3 °, and within 2 °. Most preferably it is. The same applies to the bottom value.
　図５～７は、本発明の拡散シートの高拡散角度（高アスペクト比）領域と低拡散角度（低アスペクト比）領域の配置の例を示す図である。図５、６は高拡散角度（高アスペクト比）領域２０１と低拡散角度（低アスペクト比）領域２０２が、前記拡散シート面内のｘ軸方向において周期的に存在すること、すなわち、拡散角度（アスペクト比）が図３、４の如く周期的に変化していることを示している。このようなパターンは線光源に対して用いることが好適であるが、場合によっては点光源についても用いられる。また、図７は高拡散角度（高アスペクト比）領域２０３と低拡散角度（低アスペクト比）領域２０４が、前記シート面内のｘ軸方向及びｙ軸方向において周期的に存在している図であるが、これも拡散シートのｘ軸またはｙ軸方向の断面においては図３、４の如くに拡散角度（アスペクト比）が推移している。このようなパターンは点光源に対して用いることが好適であるが、線光源に対して用いてもよい。 FIGS. 5 to 7 are diagrams showing examples of arrangement of the high diffusion angle (high aspect ratio) region and the low diffusion angle (low aspect ratio) region of the diffusion sheet of the present invention. 5 and 6 show that a high diffusion angle (high aspect ratio) region 201 and a low diffusion angle (low aspect ratio) region 202 periodically exist in the x-axis direction within the diffusion sheet surface, that is, a diffusion angle ( (Aspect ratio) changes periodically as shown in FIGS. Such a pattern is preferably used for a line light source, but is also used for a point light source in some cases. FIG. 7 is a diagram in which a high diffusion angle (high aspect ratio) region 203 and a low diffusion angle (low aspect ratio) region 204 periodically exist in the x-axis direction and the y-axis direction in the sheet surface. However, in this case, the diffusion angle (aspect ratio) changes as shown in FIGS. 3 and 4 in the cross section in the x-axis or y-axis direction of the diffusion sheet. Such a pattern is preferably used for a point light source, but may be used for a line light source.
　この拡散シートにおいては、面内の全領域における輝度ムラを低減させることを考慮すると、拡散シートから出光される拡散光の拡散角度が、０．１°以上１２０°以下の範囲であることが好ましい。また、前記拡散角度は、高い正面輝度を得るために、０．１°以上１００°以下の範囲で制御されることが好ましく、０．１°以上８０°以下の範囲で制御されることがより好ましい。特に、前記拡散シートを、表面にプリズム条列が形成された光学シートと併用した場合は、前記拡散角度が０．１°以上８０°以下の範囲となるように形成され、前記拡散角度差が大きいことが、輝度むら解消及び輝度向上の観点から、好ましい。また、拡散角度の最小値は、０．１°以上４０°以下の範囲で制御することが好ましい。輝度むら解消の観点から、拡散角度の最小値は０．１°以上３０°以下で制御されることがより好ましく、０．１°以上２０°以下で制御されることが最も好ましい。但し、光学的特性に影響を与えない部分、例えば製品としたときに光学的機能を必要としない最端部や、光学的特性に影響を与えない程度の微小な領域においては、拡散角度はこの範囲を逸脱していてもよい。 In this diffusion sheet, the diffusion angle of the diffused light emitted from the diffusion sheet is preferably in the range of 0.1 ° or more and 120 ° or less in consideration of reducing luminance unevenness in the entire area in the plane. . The diffusion angle is preferably controlled in the range of 0.1 ° to 100 °, and more preferably in the range of 0.1 ° to 80 °, in order to obtain high front luminance. preferable. In particular, when the diffusion sheet is used in combination with an optical sheet having prism rows formed on the surface, the diffusion angle is formed so as to be in the range of 0.1 ° to 80 °, and the diffusion angle difference is A large value is preferable from the viewpoint of eliminating uneven brightness and improving brightness. The minimum value of the diffusion angle is preferably controlled in the range of 0.1 ° to 40 °. From the viewpoint of eliminating luminance unevenness, the minimum value of the diffusion angle is more preferably controlled in the range of 0.1 ° to 30 °, and most preferably in the range of 0.1 ° to 20 °. However, in the part that does not affect the optical characteristics, for example, the end part that does not require the optical function when the product is used, or the minute area that does not affect the optical characteristics, the diffusion angle is It may be out of range.
　更には、拡散シート面内における前記拡散角度の最大値と最小値との差が、４０°以上８０°以下であることが好ましい。前記拡散角度差を４０°以上とすることにより、十分な拡散特性の差が得られ、光源ユニットの薄型化や光源数削減などにおける高い輝度むら解消要求に応えることができる。また、前記拡散角度差を８０°以下とし、前記シート面内の位置の変化に対する拡散特性の変化量を抑えることにより、前記拡散角分布を精細に制御することが可能となるため、輝度むら解消効果が高くなる。これにより、拡散特性の差を好ましい範囲に設定することが可能となり、輝度むらの少ない光源ユニットが得られる。特に、液晶表示装置の薄型化や光源数の削減を目的とした際に、高い輝度むら解消性能を示すため、好ましく用いられる。 Furthermore, it is preferable that the difference between the maximum value and the minimum value of the diffusion angle in the plane of the diffusion sheet is 40 ° or more and 80 ° or less. By setting the diffusion angle difference to be 40 ° or more, a sufficient difference in diffusion characteristics can be obtained, and it is possible to meet demands for eliminating high luminance unevenness in reducing the thickness of the light source unit and reducing the number of light sources. In addition, since the diffusion angle difference is set to 80 ° or less, and the amount of change in the diffusion characteristics with respect to the change in the position in the sheet surface is suppressed, the diffusion angle distribution can be finely controlled, thereby eliminating uneven brightness. Increases effectiveness. As a result, the difference in diffusion characteristics can be set within a preferable range, and a light source unit with less luminance unevenness can be obtained. In particular, it is preferably used because it exhibits high luminance unevenness elimination performance when the liquid crystal display device is thinned and the number of light sources is reduced.
　このような拡散角度は、拡散シートの表面に多数の凹凸構造を有することにより実現することができる。凹凸構造とは、例えば、表面に多数の突起部が設けられた構造である。突起部の形状は、略円錐状、略球状、略楕円体状、略レンチキュラーレンズ状、略放物線状のいずれでもよく、各突起部は、規則的に配列していても、不規則に配列していてもよい。また、突起部間は連続的な曲面でつながっていてもよい。また、不規則な凹凸が連続的な曲面でつながっている擬似ランダム構造も、好ましく用いることができる。この擬似ランダム構造としては、非平面スペックルによって特徴付けられた微細な３次元構造であることが好ましい。 Such a diffusion angle can be realized by having a large number of uneven structures on the surface of the diffusion sheet. The uneven structure is, for example, a structure in which a large number of protrusions are provided on the surface. The shape of the protrusions may be approximately conical, approximately spherical, approximately ellipsoidal, approximately lenticular lens, or approximately parabolic, and the protrusions may be regularly or irregularly arranged. It may be. Further, the protrusions may be connected by a continuous curved surface. Further, a pseudo random structure in which irregular irregularities are connected by a continuous curved surface can also be preferably used. This pseudo-random structure is preferably a fine three-dimensional structure characterized by non-planar speckles.
　非平面スペックルによって特徴付けられた３次元構造は、機械加工では困難であった１０μｍ以下の微細な凹凸構造の形成に適している。特に、非平面スペックルを用いて凹凸を形成する方法は、拡散シート上の領域に応じて、拡散角度を変えるような場合に適した製法である。また、マイクロレンズのような等方的な形状や、レンチキュラーレンズのような異方的な形状も容易に形成することができる。この凹凸構造は、モアレ抑制などの観点から、高さ及びピッチが不規則であることが好ましい。 The three-dimensional structure characterized by non-planar speckles is suitable for forming a fine concavo-convex structure of 10 μm or less, which was difficult by machining. In particular, the method of forming irregularities using non-planar speckle is a manufacturing method suitable for changing the diffusion angle in accordance with the region on the diffusion sheet. Also, an isotropic shape such as a microlens and an anisotropic shape such as a lenticular lens can be easily formed. This concavo-convex structure is preferably irregular in height and pitch from the viewpoint of suppressing moire.
　本発明の拡散シートは、面内のどこかに上記のような凹凸形状が配列されて光を拡散する機能を示す部分があればよく、シート表面が平滑になっている部分が存在していても良い。 The diffusion sheet of the present invention only needs to have a part that has the function of diffusing light by arranging the uneven shapes as described above somewhere in the plane, and there is a part where the sheet surface is smooth. Also good.
　本発明の拡散シートにおいて、該凹凸構造のアスペクト比は輝度むら抑制に大きく関係する。ここで、アスペクト比とは凹凸構造の高さをピッチで割った値をいう。また、ピッチとはある凹凸構造のトップからその隣の凹凸構造のトップまでの距離をいうものとする。つまり、該凹凸構造の高さ及びピッチが輝度むら抑制に大きく関係する。 In the diffusion sheet of the present invention, the aspect ratio of the concavo-convex structure is greatly related to suppression of uneven brightness. Here, the aspect ratio is a value obtained by dividing the height of the concavo-convex structure by the pitch. The pitch means the distance from the top of a certain uneven structure to the top of the adjacent uneven structure. That is, the height and pitch of the concavo-convex structure are greatly related to suppressing luminance unevenness.
　本発明では、シート面内の所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置でのアスペクト比を縦軸にとったアスペクト比分布図において、前記アスペクト比のピーク値と前記アスペクト比のボトム値とが複数有り、隣り合う前記ピーク値と前記ボトム値との間の拡散角度の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点におけるアスペクト比の算術平均値より大きいことを特徴とする。ここで述べる「全点」とは、測定点の全てを意味するものである。 In the present invention, in the aspect ratio distribution diagram in which the horizontal axis represents the relative position in the sheet surface in a predetermined direction within the sheet surface and the vertical axis represents the aspect ratio at the relative position in the sheet surface, the aspect ratio There are a plurality of peak values and a bottom value of the aspect ratio, and an arithmetic average value of diffusion angles between the adjacent peak values and the bottom value is between the adjacent peak value and the bottom value. It is characterized by being larger than the arithmetic average value of the aspect ratio at all the distributed points. The “all points” described here mean all the measurement points.
　アスペクト比の変化は、隣り合うピーク値とボトム値との算術平均値が、隣り合うピーク値とボトム値との間に分布するアスペクト比の算術平均値より大きければ厳密に直線状、曲線状、階段状でなくてもよく、アスペクト比の測定バラツキ等により、直線状、曲線状、階段状から若干はずれた形状や、直線と曲線の混合形状であってもよい。図４（ａ）～図４（ｆ）に、アスペクト比が直線状、曲線状、直線と曲線の混合形状に、変化している拡散シートの例が示されている。 The change in the aspect ratio is strictly linear, curved, if the arithmetic average value of the adjacent peak value and the bottom value is larger than the arithmetic average value of the aspect ratio distributed between the adjacent peak value and the bottom value, The shape may not be stepped, and may be a straight shape, a curved shape, a shape slightly deviated from the stepped shape, or a mixed shape of a straight line and a curved line due to variation in aspect ratio measurement. FIGS. 4 (a) to 4 (f) show examples of diffusion sheets in which the aspect ratio is changed to a linear shape, a curved shape, or a mixed shape of a straight line and a curved line.
　シート内の各領域におけるアスペクト比は、相対的にアスペクト比が高い領域を光源直上に配置してもよいし、相対的にアスペクト比が低い領域を光源直上に配置してもよい。また、各領域間の凹凸高さはなめらかに変化することが好ましい。特に、高アスペクト比領域に連続する複数のピーク値を含む形状が輝度むら低減の観点から好ましく、その形状は直線状又は下に凸の曲線状または直線と下に凸の曲線の混合形状であることが好ましい（図４（ｄ），（ｆ））。このようなパターンは光源が線光源の場合、特に効果的である。また、アスペクト比のボトム値があり、前記ボトム値を含む低アスペクト比領域におけるアスペクト比分布が、前記ボトム値を極小値とする下に凸の曲線状であるものも輝度むら低減の観点から好ましい（図４（ａ）～（ｅ））。図４（ｃ）はアスペクト比の分布が前記ピーク値を含み上に凸の曲線形状を有する第一の区間と、アスペクト比の分布が前記ボトム値を含み下に凸の曲線形状を有する第二の区間とを有しているが、このようなパターンは光源が点光源である場合、特に効果的である。 As for the aspect ratio in each region in the sheet, a region having a relatively high aspect ratio may be disposed immediately above the light source, or a region having a relatively low aspect ratio may be disposed directly above the light source. Moreover, it is preferable that the uneven height between the regions changes smoothly. In particular, a shape including a plurality of peak values continuous in a high aspect ratio region is preferable from the viewpoint of reducing luminance unevenness, and the shape is a linear shape or a downwardly convex curve shape or a mixed shape of a straight line and a downwardly convex curve. It is preferable (FIGS. 4D and 4F). Such a pattern is particularly effective when the light source is a linear light source. In addition, there is a bottom value of the aspect ratio, and the aspect ratio distribution in the low aspect ratio region including the bottom value is preferably a downward convex curve with the bottom value being a minimum value from the viewpoint of reducing luminance unevenness. (FIGS. 4A to 4E). FIG. 4C shows a first section in which the aspect ratio distribution includes the peak value and has a convex curve shape, and a second section in which the aspect ratio distribution includes the bottom value and has a convex curve shape. Such a pattern is particularly effective when the light source is a point light source.
　ここで、高アスペクト比領域とは、ピーク値の最大値とボトム値の最小値の算術平均値以上のアスペクト比を示す領域とし、低アスペクト領域とは、ピーク値の最大値とボトム値の最小値の算術平均値以下のアスペクト比を示す領域とする。本発明におけるピーク値とボトム値との間に分布するアスペクト比の算術平均値は、上記定義に基づくアスペクト比の分布を用いて算出するものとする。例えば、図１では、一つの高アスペクト比領域に複数（２つ）のピーク値が存在している。 Here, the high aspect ratio area is an area showing an aspect ratio that is equal to or higher than the arithmetic average value of the maximum peak value and the minimum bottom value, and the low aspect area is the minimum peak value and the minimum bottom value. The area indicates an aspect ratio that is less than or equal to the arithmetic average value. The arithmetic average value of the aspect ratio distributed between the peak value and the bottom value in the present invention is calculated using the aspect ratio distribution based on the above definition. For example, in FIG. 1, a plurality of (two) peak values exist in one high aspect ratio region.
　また、隣り合うピーク値とボトム値との間に分布するアスペクト比とは、図１の破線区間部分に存在するアスペクト比をいうものとする。すなわち、ピーク値が複数存在する場合、隣り合うボトム値に対応する位置とピーク値に対応する位置との間の区間内に存在するアスペクト比をいうものとする。 Also, the aspect ratio distributed between adjacent peak values and bottom values refers to the aspect ratio existing in the broken line section of FIG. That is, when there are a plurality of peak values, the aspect ratio exists in the section between the position corresponding to the adjacent bottom value and the position corresponding to the peak value.
　本発明において、アスペクト比の値を維持しながら、凹凸構造の高さが変化する形状とするのは、光学システムを変えずに行うことができるので、拡散シートを製造するのに安価かつ容易という観点から好ましい。 In the present invention, the shape in which the height of the concavo-convex structure changes while maintaining the value of the aspect ratio can be performed without changing the optical system, so that it is inexpensive and easy to manufacture a diffusion sheet. It is preferable from the viewpoint.
　また、本発明において、アスペクト比の値を維持しながら、凹凸構造のピッチが変化する形状とするのは、高精細な液晶を用いた場合にモアレが発生しにくいこという観点から好ましい。 In the present invention, it is preferable to use a shape in which the pitch of the concavo-convex structure changes while maintaining the value of the aspect ratio from the viewpoint that moiré is unlikely to occur when a high-definition liquid crystal is used.
　図９に、本発明の拡散シートの水平面に対して垂直で、かつ、面内のある方向に平行な断面で切断したときの形状の一例の概略図を示す。個々の凹部又は凸部の断面における端部から端部までの水平距離ｗを該凹部又は凸部の当該方向におけるピッチとし、前記水平距離ｗの範囲における最大深さ又は高さｌを該凹部又は凸部の当該方向における深さ又は高さとする。アスペクト比は、深さ又は高さｌを幅ｗで割ることによって求めることができる。 FIG. 9 shows a schematic diagram of an example of a shape when the diffusion sheet of the present invention is cut in a cross section perpendicular to the horizontal plane and parallel to a certain direction in the plane. The horizontal distance w from end to end in the cross section of each recess or projection is defined as the pitch in the direction of the recess or projection, and the maximum depth or height l in the range of the horizontal distance w is the recess or The depth or height in the direction of the convex portion. The aspect ratio can be determined by dividing the depth or height l by the width w.
　本願発明で用いるアスペクト比の値は、それぞれ、測定点を含み、拡散シート面に垂直でかつ所定の方向に平行な断面における、測定点を中心とする１００μｍの範囲に存在する凹部又は凸部のピッチ、深さ又は高さ及びアスペクト比の平均値をいう。なお、平均値は、該当エリアから最低１５個の凹部又は凸部を抽出して求めてもよい。この表面の凹凸構造は、例えば拡散シート断面の走査型電子顕微鏡像や、レーザー共焦点顕微鏡により観察することができる。 The aspect ratio values used in the present invention each include a measurement point, and a concave or convex portion existing in a range of 100 μm centering on the measurement point in a cross section perpendicular to the diffusion sheet surface and parallel to a predetermined direction. The average value of pitch, depth or height and aspect ratio. The average value may be obtained by extracting at least 15 concave portions or convex portions from the corresponding area. The uneven structure on the surface can be observed by, for example, a scanning electron microscope image of a cross section of the diffusion sheet or a laser confocal microscope.
　本発明の拡散シートにおいては、面内のどこかに凹凸形状が配列されて光を拡散する機能を示す部分があればよく、シート表面が平滑になっている部分が存在していても良い。この場合アスペクト比は０となる。 In the diffusion sheet of the present invention, it is only necessary to have a portion where the uneven shape is arranged somewhere in the plane and exhibit a function of diffusing light, and there may be a portion where the sheet surface is smooth. In this case, the aspect ratio is zero.
　ここで、全領域におけるアスペクト比が０～４の範囲内にある方が、輝度ムラの低減効果の観点から好ましい。さらに光の拡散を制御する効果を発揮するという観点からは、０～３であることがより好ましく、０～２であることがさらに好ましい。但し、光学的特性に影響を与えない部分、例えば製品としたときに光学的機能を必要としない最端部や、光学的特性に影響を与えない程度の微小な領域においての凹凸のアスペクト比はこの範囲を逸脱していてもよい。また、本発明においては、繰り返された複数のピーク値のアスペクト比は、測定された全てのピーク値のアスペクト値の差が０．２以内となることが好ましく、０．１５以内がより好ましく、０．１以内が最も好ましい。ボトム値についても同様である。 Here, the aspect ratio in the entire region is preferably in the range of 0 to 4 from the viewpoint of the effect of reducing luminance unevenness. Further, from the viewpoint of exhibiting the effect of controlling the diffusion of light, it is more preferably 0 to 3, and further preferably 0 to 2. However, the aspect ratio of the unevenness in the part that does not affect the optical characteristics, for example, the extreme end part that does not require the optical function when it is made as a product, or the minute area that does not affect the optical characteristics is You may deviate from this range. In the present invention, the aspect ratio of a plurality of repeated peak values is preferably such that the difference in aspect values of all measured peak values is within 0.2, more preferably within 0.15, Within 0.1 is most preferred. The same applies to the bottom value.
　アスペクト比の周期的変化の定義は前述の拡散角度の周期的変化の定義に準拠する。 The definition of the periodic change of the aspect ratio conforms to the definition of the periodic change of the diffusion angle described above.
　この凹凸構造を表面に有し、拡散シート上の領域に応じて拡散角度が変化するような拡散シートは、具体的には次のようにして製造することができる。まず、予め干渉露光により、レーザー光をレンズやマスクを介して感光性材料やフォトレジストに照射し、拡散角度が位置によって変化するようにスペックルパターンを形成させたサブマスタ型を作製する。レーザー照射システムを構成する部材間の距離やサイズを変えスペックルパターンの寸法、形状及び方向を調節することにより、拡散角度の範囲を制御し、異なる拡散角度をもつ凹凸構造を記録することができる。 A diffusion sheet having this uneven structure on the surface and changing the diffusion angle depending on the region on the diffusion sheet can be specifically manufactured as follows. First, a sub-master type in which a speckle pattern is formed so that the diffusion angle changes depending on the position by irradiating a photosensitive material or a photoresist with a laser beam through a lens or a mask in advance by interference exposure. By changing the distance and size between the members constituting the laser irradiation system and adjusting the size, shape and direction of the speckle pattern, the range of the diffusion angle can be controlled and the concavo-convex structure having different diffusion angles can be recorded. .
　一般に、拡散角度の範囲は、スペックルの平均サイズ及び形状に依存する。スペックルが小さければ角度範囲が広い。また、前記凹凸の単位構造は等方性のものに限らず、異方性のものを形成することもでき、両者の複合された凹凸構造とすることもできる。スペックルが横方向の長円形であれば、角度分布の形は縦方向の長円形となる。このように拡散角度が位置によって変化するようなサブマスタ型を作製する。このサブマスタ型に電鋳などの方法で金属を被着してこの金属にスペックルパターンを転写してマスタ型を作製する。光透過性樹脂層に、上記マスタ型を用いて紫外線による賦形を行って光透過性樹脂層の光取り出し面にスペックルパターンを転写する。拡散角度を位置によって変えたこの拡散シートの詳細な製造方法については、特表２００３－５２５４７２号公報（国際公開第０１／０６５４６９号）に開示されている。具体的には、光源と、光源から投射された光の光路に設けられたサイズおよび形状可変の開口を備えたマスクと、光源から投射された光により生ずる拡散パターンを記録するためのプレートと、マスクとプレートの間に配置された光を拡散させる拡散板と、光の一部をブロックするために拡散板とプレートの間に設けられたブロッカーを用い、マスクの開口とブロッカーのサイズ及び形状、拡散板の拡散度合い及び各構成部材間の距離を変化させて作る。 In general, the range of the diffusion angle depends on the average size and shape of the speckle. If speckle is small, the angle range is wide. Moreover, the unit structure of the unevenness is not limited to an isotropic one, and an anisotropic one can be formed, or an uneven structure in which both are combined can be formed. If the speckle is an oval in the horizontal direction, the shape of the angular distribution is an oval in the vertical direction. In this way, a sub-master type in which the diffusion angle changes depending on the position is manufactured. A metal is deposited on the sub-master mold by a method such as electroforming, and a speckle pattern is transferred to the metal to produce a master mold. A speckle pattern is transferred to the light extraction surface of the light-transmitting resin layer by forming the light-transmitting resin layer with ultraviolet rays using the master mold. A detailed manufacturing method of this diffusion sheet in which the diffusion angle is changed depending on the position is disclosed in JP-T-2003-525472 (International Publication No. 01/065469). Specifically, a light source, a mask provided with a size and shape variable opening provided in an optical path of light projected from the light source, a plate for recording a diffusion pattern generated by the light projected from the light source, Using a diffuser plate that diffuses light disposed between the mask and the plate, and a blocker provided between the diffuser plate and the plate to block part of the light, the size and shape of the mask opening and blocker, It is made by changing the diffusion degree of the diffusion plate and the distance between the constituent members.
　たとえば
１．マスクの開口形状を縦長にすることで、プレート上に記録される凸部の底面の形状を横長の楕円にし、縦長の楕円拡散能を示す（直交する２方向の拡散角度が異なる）領域を形成する。
２．マスクの開口形状を正方形にすることで、プレート上に記録される凸部の底面の形状を等方にし、等方拡散能を示す（全方向で拡散角度が同一となる）領域を形成する。 For example: By making the mask opening shape vertically long, the shape of the bottom surface of the convex portion recorded on the plate is made into a horizontally long ellipse, and a region having a vertically long elliptical diffusivity (diffusing angles in two orthogonal directions are different) is formed. To do.
2. By making the mask opening shape square, the shape of the bottom surface of the convex portion recorded on the plate is isotropic, and a region showing isotropic diffusion ability (the diffusion angle is the same in all directions) is formed.
　上記１および２のパターンを組み合わせて、周期的パターンを形成すれば、本発明の拡散シート、すなわち面内で拡散角度あるいは表面の凹凸形状のアスペクト比の比が周期的に変化する拡散シートが製造できる。 When the periodic patterns are formed by combining the patterns 1 and 2 above, the diffusion sheet of the present invention, that is, the diffusion sheet in which the diffusion angle or the ratio of the aspect ratio of the concavo-convex shape on the surface changes periodically is manufactured. it can.
　表面構造の凹凸高さは、例えば走査型電子顕微鏡で観察した拡散シート断面形状のピッチやアスペクト比、表面粗さ等から判断できる。また、レーザー共焦点顕微鏡による拡散シート表面の観察像からも、前記ピッチ、アスペクト比や、表面粗さ等を読み取ることができる。例えば、ピッチが短いほど、或いはアスペクト比が大きいほど、或いは表面粗さが大きいものほど凹凸高さが高いと見なすことができる。 The unevenness height of the surface structure can be determined from, for example, the pitch, aspect ratio, surface roughness, etc. of the cross-sectional shape of the diffusion sheet observed with a scanning electron microscope. Further, the pitch, aspect ratio, surface roughness, and the like can also be read from an observation image of the diffusion sheet surface by a laser confocal microscope. For example, as the pitch is shorter, the aspect ratio is larger, or the surface roughness is larger, it can be considered that the unevenness height is higher.
　また、本発明の拡散シートにおける凹凸構造は、シートの出光面側にあっても入光面側にあってもよい。凹凸構造が出光面側にあることは、輝度の低下を最小限に抑えつつ輝度むらを低減できるという観点から好ましい。また、凹凸構造が入光面にあることは、光源と拡散シートの面内における位置合わせが容易に行えるという観点から好ましい。 Further, the uneven structure in the diffusion sheet of the present invention may be on the light exit surface side or the light entrance surface side of the sheet. The concavo-convex structure on the light exit surface side is preferable from the viewpoint that the luminance unevenness can be reduced while minimizing the decrease in luminance. Moreover, it is preferable that the concavo-convex structure is on the light incident surface from the viewpoint of easy alignment in the surface of the light source and the diffusion sheet.
　凹凸構造がある面と反対側の面は、平滑面、凹凸面、マット面などであってもよい。輝度向上、および輝度ムラ軽減の観点から、凹凸構造がある面と反対側の面は、平滑面となっていることが好ましい。なお、一般に拡散シートを積層する場合等に、傷つき防止のため、平滑性を失わない範囲で、凹凸構造がある面と反対側の面に極微量のビーズを塗布する場合がある。このような場合も平滑面に含まれるものとする。 The surface opposite to the surface having the uneven structure may be a smooth surface, an uneven surface, a mat surface, or the like. From the viewpoint of improving the luminance and reducing the luminance unevenness, it is preferable that the surface opposite to the surface having the concavo-convex structure is a smooth surface. In general, when a diffusion sheet is laminated, a very small amount of beads may be applied to the surface opposite to the surface having the concavo-convex structure as long as smoothness is not lost in order to prevent damage. Such a case is also included in the smooth surface.
（実施の形態２）
　実施の形態２では、本発明の光線制御ユニットの一例について説明する。 (Embodiment 2)
In Embodiment 2, an example of the light beam control unit of the present invention will be described.
　実施の形態２で示す光線制御ユニットにおいては、シート面内で拡散角度を周期的に変化させた拡散シートと、レンズが表面に形成された光学シートとを配設した構成とすることにより、光源ユニットの薄型化や光源数削減などにおける高い輝度むら解消要求に応えることができる。特に、液晶表示装置の薄型化や光源数の削減を目的とした際に、前記光学シートのレンズ形成面側に、前記拡散シートを配置した構成の光線制御ユニットが高い輝度むら解消性能を示すため、好ましく用いられる。 In the light beam control unit shown in the second embodiment, the light source has a configuration in which a diffusion sheet whose diffusion angle is periodically changed in the sheet surface and an optical sheet having a lens formed on the surface thereof are disposed. It is possible to meet demands for eliminating high luminance unevenness, such as thinning the unit and reducing the number of light sources. In particular, when aiming at thinning the liquid crystal display device and reducing the number of light sources, the light beam control unit having the configuration in which the diffusion sheet is disposed on the lens forming surface side of the optical sheet exhibits high luminance unevenness elimination performance. Are preferably used.
　実施の形態２で示す光線制御ユニットを構成する拡散シートとしては、高拡散角度（高アスペクト比）領域２０１と低拡散角度（低アスペクト比）領域２０２が、前記拡散シート面内のｘ軸方向において周期的に存在すること、すなわち、拡散角度（アスペクト比）が周期的に変化する構成とすることができる（図５、６参照）。また、高拡散角度（高アスペクト比）領域２０３と低拡散角度（低アスペクト比）領域２０４が、前記シート面内のｘ軸方向及びｙ軸方向において周期的に存在すること、すなわち、拡散角度（アスペクト比）が周期的に変化する構成とすることもできる（図７参照）。光線制御ユニットを構成する拡散シートの一例として、上記実施の形態１で示した拡散シートを適用することもできる。 As the diffusion sheet constituting the light beam control unit shown in the second embodiment, a high diffusion angle (high aspect ratio) region 201 and a low diffusion angle (low aspect ratio) region 202 are arranged in the x-axis direction in the diffusion sheet plane. It can be configured to exist periodically, that is, the diffusion angle (aspect ratio) changes periodically (see FIGS. 5 and 6). Further, the high diffusion angle (high aspect ratio) region 203 and the low diffusion angle (low aspect ratio) region 204 periodically exist in the x-axis direction and the y-axis direction in the sheet surface, that is, the diffusion angle ( The aspect ratio may be changed periodically (see FIG. 7). As an example of the diffusion sheet constituting the light beam control unit, the diffusion sheet shown in the first embodiment can also be applied.
　実施の形態２で示す光線制御ユニットは、冷陰極管（ＣＣＦＬ）、外部電極蛍光灯（ＥＥＦＬ）、熱陰極管（ＨＣＦＬ）などの線光源や、発光ダイオード（ＬＥＤ）などの点光源に対して好ましく用いられる。前記光線制御ユニットを構成する拡散シートについては、光源が線光源の場合は、線光源の長手方向と直交する方向に、前記拡散シートの拡散角度が周期的に変化していることが好ましい。また、前記拡散シートについて、光源が点光源の場合は、シート面内の直交する２方向で前記拡散角度が周期的に変化していることが好ましい。 The light beam control unit shown in the second embodiment is applied to a line light source such as a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp (EEFL), a hot cathode fluorescent lamp (HCFL), or a point light source such as a light emitting diode (LED). Preferably used. About the diffusion sheet which comprises the said light ray control unit, when a light source is a linear light source, it is preferable that the diffusion angle of the said diffusion sheet is changing periodically in the direction orthogonal to the longitudinal direction of a linear light source. Moreover, about the said diffusion sheet, when the light source is a point light source, it is preferable that the said diffusion angle is changing periodically in two orthogonal directions within a sheet surface.
　図１２は、実施の形態２で示す光線制御ユニットを斜め上方から俯瞰した場合の模式図であり、表面に複数のレンズにより構成されたレンズ部が形成されたレンズ賦形光学シート１４のレンズ形成面側に、前記拡散シート１５が配置されている。図１３は、図１２の切断面における、光線制御ユニットの断面構造の模式図である。光線制御ユニットとして用いる場合、輝度ムラ解消及び輝度向上の観点から、前記レンズ形成面側を出光面とすることが好ましい。 FIG. 12 is a schematic diagram when the light beam control unit shown in the second embodiment is viewed from obliquely above, and the lens formation of the lens-shaped optical sheet 14 in which a lens portion composed of a plurality of lenses is formed on the surface. The diffusion sheet 15 is disposed on the surface side. FIG. 13 is a schematic diagram of a cross-sectional structure of the light beam control unit in the cut surface of FIG. When used as a light beam control unit, it is preferable that the lens-forming surface side be the light exit surface from the viewpoint of eliminating uneven brightness and improving brightness.
　また、前記レンズ部が形成された光学シートは、光源からの光を入光する入光面と、前記入光面から入光した光を出光する出光面と、を有する。この光学シートにおいて、レンズ部が形成されていない面側は、平滑面、凹凸面、マット面などであってもよい。輝度向上、及び輝度むら軽減の観点から、出光面側がレンズ形成面となっていることが好ましく、さらに、入光面側が平滑面或いはマット面となっていることがより好ましい。前記マット面は、無機微粒子の塗布や、凹凸構造を有する賦形ロールによる凹凸であることが好ましい。 Further, the optical sheet on which the lens portion is formed has a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface. In this optical sheet, the surface side on which the lens portion is not formed may be a smooth surface, an uneven surface, a mat surface, or the like. From the viewpoint of improving brightness and reducing uneven brightness, the light exit surface side is preferably a lens forming surface, and the light entrance surface side is more preferably a smooth surface or a mat surface. The mat surface is preferably uneven by applying inorganic fine particles or by a shaping roll having an uneven structure.
　前記レンズ部が形成された光学シートは、紫外線硬化樹脂による微細な凹凸構造がポリエステル系樹脂、トリアセチルセルロース、或いはポリカーボネート等の基材シート上に転写された形態として、用いることができる。また、前記光学シートは、表面にレンズ部が形成されているものであれば様々なものを用いることができ、例えば、ポリスチレン、アクリル系樹脂、ポリカーボネート、シクロオレフィンポリマーなどの樹脂板に、プレス成形、射出成形或いは押出成形によってレンズが形成された形態も好ましく用いられる。特に、前記光線制御ユニットにおいて、前記拡散シートを支持するため、厚さ１ｍｍ以上２ｍｍ以下の板状にプレス成形、射出成形或いは押出成形された形態が好ましく、輝度むら解消性能向上のため、樹脂板内部に、光を拡散させる効果がある有機ポリマーや、無機微粒子を添加したものを好ましく用いることができる。このような光学シートとしては、例えば、旭化成拡散板ＴＭＤＬ/ＤＨシリーズ（旭化成イーマテリアルズ（株）製）、ゼオノアシリーズ（日本ゼオン（株）製）、等が挙げられる。 The optical sheet on which the lens portion is formed can be used as a form in which a fine concavo-convex structure made of an ultraviolet curable resin is transferred onto a base material sheet such as a polyester resin, triacetyl cellulose, or polycarbonate. In addition, various optical sheets can be used as long as the lens part is formed on the surface. For example, press molding is performed on resin plates such as polystyrene, acrylic resin, polycarbonate, and cycloolefin polymer. A form in which a lens is formed by injection molding or extrusion molding is also preferably used. In particular, in the light beam control unit, in order to support the diffusion sheet, a form that is press-molded, injection-molded or extruded into a plate shape having a thickness of 1 mm to 2 mm is preferable. An organic polymer having an effect of diffusing light or an inorganic fine particle added therein can be preferably used. Examples of such optical sheets include Asahi Kasei Diffusion Plate TM DL / DH series (Asahi Kasei E-Materials Co., Ltd.), Zeonore Series (Nihon Zeon Co., Ltd.), and the like.
　実施の形態２で示す光線制御ユニットを構成し、表面にレンズ部が形成された前記光学シートは、光源が線光源である場合や、光源が点光源でかつ前記点光源の配置間隔が直交する２方向で異なるような場合において用いることができ、前記光学シートのレンズ部が単位レンズを複数配列することにより構成され、前記単位レンズの底面形状が異方性を有する形状であることが好ましい。 In the optical sheet that constitutes the light beam control unit shown in the second embodiment and has a lens portion formed on the surface, the light source is a line light source, or the light source is a point light source and the arrangement intervals of the point light sources are orthogonal. It can be used in cases where they differ in two directions, and it is preferable that the lens portion of the optical sheet is formed by arranging a plurality of unit lenses, and the bottom shape of the unit lenses is a shape having anisotropy.
　図１４（ａ）～（ｆ）は、前記単位レンズの底面形状の例を示した図である。光源が点光源で、かつ前記光源の配置間隔が直交する２方向で異なるような場合は、図１４（ａ）～（ｄ）のような前記単位レンズの底面形状が好ましく、前記単位レンズの底面形状で異方性の強い方向と、前記点光源の配置間隔が狭い方向が平行であることがより好ましい。また、光源が線光源である場合は、図１４（ｅ），（ｆ）のような前記単位レンズの底面形状が好ましく、前記単位レンズの底面形状で異方性の強い方向、すなわち底面形状が楕円の場合は長径方向、底面形状が長方形の場合は長辺方向と、線光源の長手方向が平行であることがより好ましい。 FIGS. 14A to 14F are diagrams showing examples of the bottom shape of the unit lens. When the light source is a point light source and the arrangement interval of the light sources is different in two orthogonal directions, the bottom shape of the unit lens as shown in FIGS. 14A to 14D is preferable, and the bottom surface of the unit lens is preferable. More preferably, the direction in which the shape is strongly anisotropic is parallel to the direction in which the arrangement interval of the point light sources is narrow. Further, when the light source is a line light source, the bottom shape of the unit lens as shown in FIGS. 14E and 14F is preferable, and the bottom shape of the unit lens has a strong anisotropic direction, that is, the bottom shape. In the case of an ellipse, it is more preferable that the major axis direction is parallel, and in the case where the bottom shape is a rectangle, the long side direction is parallel to the longitudinal direction of the line light source.
　前記光線制御ユニットを構成し、表面にプリズム条列或いはレンチキュラーレンズが形成された前記光学シートは、線光源に対して好ましく用いられ、線光源の長手方向と前記レンズ部の長手方向が平行に配置されることがより好ましい。図１５（ａ）、（ｂ）には、前記単位レンズがプリズム条列である例、また、図１５（ｃ）には前記単位レンズがレンチキュラーレンズである例が示されている。他の光学シートとの擦れ防止の観点から、プリズムの先端を丸まった構造としたものも好ましく用いられる。また、モアレ防止の観点から、図１５（ｂ）のように、プリズム先端の稜線をうねらせた構造としたものも好ましく用いられる。 The optical sheet constituting the light beam control unit and having a prism array or lenticular lens formed on the surface thereof is preferably used for a line light source, and the longitudinal direction of the line light source and the longitudinal direction of the lens part are arranged in parallel. More preferably. FIGS. 15A and 15B show an example in which the unit lens is a prism array, and FIG. 15C shows an example in which the unit lens is a lenticular lens. From the viewpoint of preventing rubbing with other optical sheets, a prism with a rounded tip is preferably used. From the viewpoint of preventing moire, a structure in which the ridge line of the prism tip is waved as shown in FIG. 15B is also preferably used.
　光線制御ユニットを構成し、表面にレンズ部が形成された前記光学シートは、光源が点光源でかつ前記点光源の配置間隔が直交する２方向で等しいような場合において用いることができ、前記光学シートのレンズ部が単位レンズを複数配列することにより構成され、前記単位レンズの底面形状が等方性を有する形状であることが好ましい。 The optical sheet constituting a light beam control unit and having a lens portion formed on the surface thereof can be used in the case where the light source is a point light source and the arrangement interval of the point light sources is equal in two orthogonal directions. It is preferable that the lens portion of the sheet is configured by arranging a plurality of unit lenses, and the bottom surface shape of the unit lens is an isotropic shape.
　図１６（ａ）～（ｅ）には、等方性を有するような前記単位レンズの底面形状の例が示されている。輝度むら解消の観点から、前記単位レンズがシート表面に稠密に形成され、前記底面形状が図１６（ａ），（ｄ），（ｅ）のような形状であることが好ましい。特に、前記単位レンズの底面形状が、円形、正方形、正６角形であることが好ましい。 FIGS. 16A to 16E show examples of the bottom shape of the unit lens having isotropic properties. From the viewpoint of eliminating luminance unevenness, it is preferable that the unit lenses are densely formed on the sheet surface, and the shape of the bottom surface is as shown in FIGS. 16 (a), (d), and (e). In particular, the bottom shape of the unit lens is preferably a circle, a square, or a regular hexagon.
　前記光線制御ユニットを構成し、表面にマイクロレンズ或いはマイクロプリズムが形成された前記光学シートは、点光源に対して好ましく用いられる。図１７（ａ）、（ｂ）には、前記単位レンズがマイクロレンズである例、また、図１７（ｃ）～（ｅ）には前記単位レンズがマイクロプリズムである例が示されている。他の光学シートとの擦れ防止の観点から、プリズムの先端を丸まった構造としたものも好ましく用いられる。また、前記マイクロレンズ或いはマイクロプリズムは、凹形状でも凸形状でも良い。 The optical sheet constituting the light beam control unit and having a microlens or microprism formed on the surface is preferably used for a point light source. FIGS. 17A and 17B show examples in which the unit lens is a microlens, and FIGS. 17C to 17E show examples in which the unit lens is a microprism. From the viewpoint of preventing rubbing with other optical sheets, a prism with a rounded tip is preferably used. The microlens or microprism may be concave or convex.
　光線制御ユニットを構成し、表面にレンズ部が形成された前記光学シートは、光源が線光源と点光源の混在である場合や、光源が点光源であり、かつ前記点光源の配置間隔が直交する２方向で等間隔の領域と、直交する２方向で間隔が異なる領域が混在しているような場合において用いることができ、前記光学シートのレンズ部が単位レンズを複数配列することにより構成され、前記単位レンズの底面形状が、異方性を有する形状のレンズと、等方性を有する形状のレンズとが複合配列していることが好ましい。このような光学シート表面に形成された単位レンズの底面形状の例が、図１８（ａ）～（ｅ）に示されている。 The optical sheet that constitutes a light beam control unit and has a lens portion formed on the surface thereof has a light source that is a mixture of a line light source and a point light source, or the light source is a point light source and the arrangement interval of the point light sources is orthogonal. Can be used in the case where there are a mixture of equally spaced regions in the two directions and different regions in the two orthogonal directions, and the lens portion of the optical sheet is configured by arranging a plurality of unit lenses. It is preferable that the bottom surface of the unit lens has a complex array of lenses having anisotropy and isotropic lenses. Examples of the bottom shape of the unit lens formed on the surface of the optical sheet are shown in FIGS. 18 (a) to 18 (e).
　実施の形態２に示す光線制御ユニットでは、輝度が一定となるように、拡散角度を最適化することで、輝度むらの軽減を図っている。実施の形態２に示す光線制御ユニットを構成する拡散シートは、シート面内の相対位置を横軸とし、前記シート面内の位置における拡散角度を縦軸とした場合の拡散角度分布図が、図１０に示す構成とすることができる。図１０（ａ）から図１０（ｆ）には、拡散角度が、直線状、曲線状、直線と曲線の混合形状、或いは階段状に、変化している拡散シートの例が示されている。拡散角度の変化は、厳密に直線状、曲線状、階段状でなくてもよく、拡散角度の測定バラツキ等により、直線状、曲線状、階段状から若干はずれた形状や、直線と曲線の混合形状であってもよい。特に、拡散角度は、前記拡散シートの面内において、なめらかに変化することが好ましい。 In the light beam control unit shown in the second embodiment, the luminance unevenness is reduced by optimizing the diffusion angle so that the luminance is constant. The diffusion sheet constituting the light beam control unit shown in the second embodiment has a diffusion angle distribution diagram in the case where the horizontal axis is the relative position in the sheet surface and the vertical axis is the diffusion angle at the position in the sheet surface. The configuration shown in FIG. FIG. 10A to FIG. 10F show examples of diffusion sheets in which the diffusion angle changes in a linear shape, a curved shape, a mixed shape of straight lines and curves, or a staircase shape. The change in the diffusion angle does not have to be strictly linear, curved, or stepped, but may vary slightly from linear, curved, or stepped due to dispersion angle measurement variations, etc. It may be a shape. In particular, it is preferable that the diffusion angle changes smoothly in the plane of the diffusion sheet.
　また、シート面内の相対位置を横軸とし、前記シート面内の位置におけるアスペクト比を縦軸とした場合のアスペクト比分布図が、図１１に示す構成とすることができる。図１１（ａ）から図１１（ｆ）には、アスペクト比が、直線状、曲線状、直線と曲線の混合形状、或いは階段状に、変化している拡散シートの例が示されている。アスペクト比の変化は、厳密に直線状、曲線状、階段状でなくてもよく、アスペクト比の測定バラツキ等により、直線状、曲線状、階段状から若干はずれた形状や、直線と曲線の混合形状であってもよい。アスペクト比は、前記拡散シートの面内において、なめらかに変化することが好ましい。 Further, an aspect ratio distribution diagram in which the relative position in the sheet surface is the horizontal axis and the aspect ratio at the position in the sheet surface is the vertical axis can be configured as shown in FIG. FIG. 11A to FIG. 11F show examples of diffusion sheets in which the aspect ratio changes in a linear shape, a curved shape, a mixed shape of straight lines and curves, or a staircase shape. The change in aspect ratio does not have to be strictly linear, curved, or stepped. Depending on the measurement variation of the aspect ratio, the shape is slightly different from linear, curved, or stepped, or a mixture of lines and curves. It may be a shape. It is preferable that the aspect ratio changes smoothly in the plane of the diffusion sheet.
　また、実施の形態１の拡散シートをここで用いることもできる。例としては、図３（ａ）～（ｆ）に示すように面内において拡散角度が変化するもの、或いは図４（ａ）～（ｆ）に示すようにアスペクト比が変化するものが挙げられる。 Also, the diffusion sheet of Embodiment 1 can be used here. Examples include those in which the diffusion angle changes in the plane as shown in FIGS. 3 (a) to (f), or those in which the aspect ratio changes as shown in FIGS. 4 (a) to (f). .
　光線制御ユニットを構成する拡散シートの拡散角度は、０．１°以上１２０°以下の範囲で制御することが好ましい。ここで、輝度の均一性をさらに向上させるために、拡散角度の差及び拡散角度の分布状態を調整することができる。特に、薄型化するために光源と光学シートとの距離を近づけた場合（図２７（ａ））や、光源同士の間隔を広げた場合（図２７（ｂ））は輝度むらが大きくなるため、拡散角度の差は大きい方が好ましい。また、前記拡散角度は、高い正面輝度を得るために、０．１°以上１００°以下の範囲で制御されることが好ましく、０．１°以上８０°以下の範囲で制御されることがより好ましい。 The diffusion angle of the diffusion sheet constituting the light beam control unit is preferably controlled in the range of 0.1 ° to 120 °. Here, in order to further improve the uniformity of brightness, the difference in diffusion angle and the distribution state of the diffusion angle can be adjusted. In particular, when the distance between the light source and the optical sheet is reduced in order to reduce the thickness (FIG. 27A), or when the distance between the light sources is increased (FIG. 27B), the luminance unevenness increases. A larger difference in diffusion angle is preferred. The diffusion angle is preferably controlled in the range of 0.1 ° to 100 °, and more preferably in the range of 0.1 ° to 80 °, in order to obtain high front luminance. preferable.
　また、光線制御ユニットを構成する拡散シートのアスペクト比は０～４の範囲内にある方が、輝度ムラの低減効果の観点から好ましい。さらに光の拡散を制御する効果を発揮するという観点からは、０～３であることがより好ましく、０～２であることがさらに好ましい。但し、光学的特性に影響を与えない部分、例えば製品としたときに光学的機能を必要としない最端部、光学的特性に影響を与えない程度の微小な領域においての拡散角度や、凹凸のアスペクト比はこの範囲を逸脱していてもよい。 Also, the aspect ratio of the diffusion sheet constituting the light beam control unit is preferably in the range of 0 to 4 from the viewpoint of the effect of reducing luminance unevenness. Further, from the viewpoint of exhibiting the effect of controlling the diffusion of light, it is more preferably 0 to 3, and further preferably 0 to 2. However, the diffusion angle or unevenness in the part that does not affect the optical characteristics, for example, the endmost part that does not require the optical function when the product is manufactured, or the minute area that does not affect the optical characteristics The aspect ratio may deviate from this range.
　このような拡散角度またはアスペクト比は、上記実施の形態で示したように、拡散シートの表面に多数の凹凸構造を有することにより実現することができる。 Such a diffusion angle or aspect ratio can be realized by having a large number of concavo-convex structures on the surface of the diffusion sheet as shown in the above embodiment.
　また、光線制御ユニットにおいて、拡散シートの出光面或いは入光面のどちら側に多数の凹凸構造が設けられていても良く、凹凸構造の設けられていない面側は、平滑面、凹凸面、マット面などであってもよい。輝度向上、及び輝度むら軽減の観点から、出光面側が凹凸面となっていることが好ましく、さらに入光面側が平滑面或いはマット面となっていることがより好ましい。なお、一般に拡散シートを積層する場合等に、傷つき防止のため、光学特性を損なわない範囲で、入光面に極微量のビーズを塗布する場合がある。このような場合も平滑面に含まれるものとする。 Further, in the light beam control unit, a large number of uneven structures may be provided on either the light exit surface or the light entrance surface of the diffusion sheet. The surface side where the uneven structure is not provided is a smooth surface, an uneven surface, a mat. It may be a surface. From the viewpoint of improving brightness and reducing unevenness in brightness, the light exit surface side is preferably an uneven surface, and the light entrance surface side is more preferably a smooth surface or a mat surface. In general, when a diffusion sheet is laminated, a very small amount of beads may be applied to the light incident surface within a range that does not impair optical characteristics in order to prevent damage. Such a case is also included in the smooth surface.
　この凹凸形状を表面に有し、拡散シート面内の領域において拡散角度が変化するような拡散シートは、上記実施の形態１で示した方法により製造することができる。 A diffusion sheet having this uneven shape on the surface and changing the diffusion angle in a region within the surface of the diffusion sheet can be manufactured by the method described in the first embodiment.
（実施の形態３）
　本実施の形態では、上記実施の形態１で示した拡散シート、実施の形態２で示した光線制御ユニットを適用した光源ユニットについて説明する。 (Embodiment 3)
In this embodiment, a light source unit to which the diffusion sheet shown in Embodiment 1 and the light beam control unit shown in Embodiment 2 are applied will be described.
　図１９、図２０に本実施の形態で示す光源ユニットの概略構成を示す。図１９は、光源として冷陰極管（ＣＣＦＬ）を用いた場合を示し、図２０は、光源としてＬＥＤ（発光ダイオード）を用いた場合を示している。 19 and 20 show a schematic configuration of the light source unit shown in the present embodiment. FIG. 19 shows a case where a cold cathode fluorescent lamp (CCFL) is used as a light source, and FIG. 20 shows a case where an LED (light emitting diode) is used as a light source.
　光源ユニットは、基本的には、光源（光源１１又は光源１２）と、光源１１、１２の上方に配設された拡散シート１５と、を具備する構成を採ることができる（図１９（ａ）、図２０（ａ）参照）。また、光源１１、１２の下方には、光を反射させるための反射シート１３が使用されることが好ましい。この場合、拡散シート１５として、上記実施の形態１で示した拡散シートを適用することができる。 The light source unit can basically have a configuration including a light source (light source 11 or light source 12) and a diffusion sheet 15 disposed above the light sources 11 and 12 (FIG. 19A). FIG. 20 (a)). Moreover, it is preferable that a reflection sheet 13 for reflecting light is used below the light sources 11 and 12. In this case, the diffusion sheet shown in the first embodiment can be applied as the diffusion sheet 15.
　また、光学ユニットは、上記構成を有していれば、さらに、光学シート、拡散シート等を配設してもよく、例えば、光源１１、１２と拡散シート１５の間に光学シート１４を設けた構成とすることができる（図１９（ｂ）、図２０（ｂ）参照）。 Further, if the optical unit has the above configuration, an optical sheet, a diffusion sheet or the like may be further provided. For example, an optical sheet 14 is provided between the light sources 11 and 12 and the diffusion sheet 15. It can be set as a structure (refer FIG.19 (b) and FIG.20 (b)).
　また、図１９、２０に示す構成において、拡散シート１５と光学シート１４を具備する光線制御ユニットとして、上記実施の形態２で示した光線制御ユニットを適用することができる。この場合、前記光線制御ユニットにおいて、前記光学シートのレンズ面側を出光面とするのが好ましく、前記拡散シートの凹凸形成面側を出光面とするのがより好ましい。 19 and 20, the light beam control unit shown in the second embodiment can be applied as the light beam control unit including the diffusion sheet 15 and the optical sheet 14. In this case, in the light beam control unit, the lens surface side of the optical sheet is preferably a light exit surface, and the unevenness forming surface side of the diffusion sheet is more preferably a light exit surface.
　反射シート１３は、光を反射させることのできるものであれば、様々なものを用いることができる。例えば、ポリエステル、ポリカーボネートなどの樹脂を発泡させて内部に微細な空気の粒を入れシート状としたもの、２成分以上の樹脂を混合してシート状としたもの、屈折率の異なる樹脂層を積層したシート、などを用いることができる。また、前記反射シートは、表面に凹凸形状が形成されていても良い。これらには、必要に応じて、表面に無機微粒子などを添加したものを用いることができる。 As the reflection sheet 13, various materials can be used as long as they can reflect light. For example, a resin such as polyester or polycarbonate is foamed and fine air particles are made into a sheet, and a sheet is formed by mixing two or more resins, and resin layers with different refractive indexes are laminated. Sheet, etc. can be used. The reflection sheet may have a concavo-convex shape on the surface. As these, those having inorganic fine particles added to the surface can be used as necessary.
　光源ユニットには、複数の光源を用いている。光源としては、図１９に示すような冷陰極管（ＣＣＦＬ）１１などの線光源や、図２０に示すようなＬＥＤ（発光ダイオード）１２、レーザーなどの点光源を用いることができる。この場合、前記光源１１，１２は拡散シート１５の入光面及び出光面に対して、直下に配列されている。 The light source unit uses a plurality of light sources. As the light source, a linear light source such as a cold cathode tube (CCFL) 11 as shown in FIG. 19 or a point light source such as an LED (light emitting diode) 12 and a laser as shown in FIG. 20 can be used. In this case, the light sources 11 and 12 are arranged directly below the light incident surface and the light outgoing surface of the diffusion sheet 15.
　また、光源ユニットに適用できる拡散シートとしては、測定方向によらず、ほぼ同じ拡散角度が得られる等方拡散シートと、測定方向によって、拡散角度が異なる異方拡散シートの両方を用いることができる。異方拡散シートとは、例えば、直交する２つの方向で拡散角度を測定した場合に、拡散角度が異なるような拡散シートである。 Further, as the diffusion sheet applicable to the light source unit, both an isotropic diffusion sheet that can obtain substantially the same diffusion angle regardless of the measurement direction and an anisotropic diffusion sheet that has a different diffusion angle depending on the measurement direction can be used. . An anisotropic diffusion sheet is, for example, a diffusion sheet having different diffusion angles when the diffusion angles are measured in two orthogonal directions.
　本実施の形態で示す光源ユニットは、前記拡散シートの拡散角度分布の周期と、前記拡散シートの入光面における照度分布の周期とを等しくしたことを特徴とする。拡散シートの入光面における照度分布は、例えばＥＬＤＩＭ社のＥＺＣＯＮＴＲＡＳＴＸＬ８８などによって測定できる。具体的には、拡散シートが設けられる光源ユニットにおいて、前記拡散シートを除き、拡散シートの入光面が位置する箇所に装置の焦点を定めて全方位輝度分布を測定し、その結果から積算光束量（Integrated Intensity）を得る、ということを面内測定対象範囲において繰り返すことで測定する。 The light source unit shown in the present embodiment is characterized in that the period of the diffusion angle distribution of the diffusion sheet is equal to the period of the illuminance distribution on the light incident surface of the diffusion sheet. The illuminance distribution on the light incident surface of the diffusion sheet can be measured by, for example, EZCONTRASTXL88 manufactured by ELDIM. Specifically, in the light source unit provided with the diffusion sheet, the omnidirectional luminance distribution is measured with the apparatus focused on the position where the light incident surface of the diffusion sheet is located, excluding the diffusion sheet, and the integrated luminous flux is calculated from the result. It is measured by repeating the process of obtaining the quantity (Integrated Intensity) in the in-plane measurement target range.
　図２１は、前記光源ユニットの例について、斜め上方から俯瞰した場合の模式図である。図２１に示す光源ユニットにおいて、拡散シート１５は、前記拡散角度が周期的に分布し、さらに前記拡散角度が周期的に分布する方向と、ＣＣＦＬ光源１１の長手方向と直交する方向が一致するように配置されている。なお、図２１において、図２１（ｂ）は、図２１（ａ）の構成に光学シート１４を追加した構成となっている。 FIG. 21 is a schematic diagram of an example of the light source unit as viewed from obliquely above. In the light source unit shown in FIG. 21, in the diffusion sheet 15, the diffusion angle is periodically distributed, and the direction in which the diffusion angle is periodically distributed coincides with the direction orthogonal to the longitudinal direction of the CCFL light source 11. Is arranged. In FIG. 21, FIG. 21B has a configuration in which the optical sheet 14 is added to the configuration of FIG.
　図２２は、光源ユニットにおいて、光源の間隔と、前記拡散シートの拡散角度分布周期を示した図である。図２１において、前記拡散シートの入光面における照度分布の周期は光源同士の間隔と等しいため、拡散シート面内の拡散角度（アスペクト比）分布周期を、光源間隔と略等しくすることが好ましい。前記拡散シートの入光面の照度分布において、光源直上領域の照度が高い場合、輝度むら解消の観点から、前記拡散シートの高拡散角度（高アスペクト比）領域を配置することが好ましい。図２２には、前記拡散シートの入光面における照度分布に対応するように設計した、前記拡散角度分布の例が示されている。 FIG. 22 is a diagram showing a light source interval and a diffusion angle distribution period of the diffusion sheet in the light source unit. In FIG. 21, since the period of the illuminance distribution on the light incident surface of the diffusion sheet is equal to the interval between the light sources, it is preferable that the diffusion angle (aspect ratio) distribution period in the diffusion sheet surface is substantially equal to the light source interval. In the illuminance distribution on the light incident surface of the diffusion sheet, when the illuminance directly above the light source is high, it is preferable to dispose a high diffusion angle (high aspect ratio) region of the diffusion sheet from the viewpoint of eliminating luminance unevenness. FIG. 22 shows an example of the diffusion angle distribution designed to correspond to the illuminance distribution on the light incident surface of the diffusion sheet.
　拡散シート１５の拡散角度は、０．１°以上～１２０°以下の範囲で制御することが好ましい。また、特に、輝度の均一化をさらに向上させるために、光源１１，１２と、拡散シート１５との間に、別の拡散板を、例えば、拡散剤を含む拡散板を配設した場合には、好ましくは０．１°以上～１００°以下の範囲、さらに好ましくは０．１°以上８０°以下の範囲で制御されるのが好ましい。さらに、アレイ状のプリズム配列構造を有する光学シートと組み合わせて用いる場合、例えば、拡散シート１５の上方に、アレイ状のプリズム配列構造を有する光学シートを配設する場合は、０．１°以上～８０°以下の範囲で制御されるのが好ましい。 The diffusion angle of the diffusion sheet 15 is preferably controlled in the range of 0.1 ° to 120 °. In particular, in order to further improve the uniformity of the brightness, when another diffusion plate, for example, a diffusion plate containing a diffusion agent is disposed between the light sources 11 and 12 and the diffusion sheet 15. It is preferably controlled in the range of 0.1 ° to 100 °, more preferably 0.1 ° to 80 °. Further, when used in combination with an optical sheet having an arrayed prism arrangement structure, for example, when an optical sheet having an arrayed prism arrangement structure is disposed above the diffusion sheet 15, it is 0.1 ° or more and It is preferably controlled within a range of 80 ° or less.
　凹凸高さについては、例えば凹凸構造のピッチを５μｍとすると、液晶の高精細化（ピクセル狭小化）でもモアレが出ないという観点から、０μｍから２０μｍ（アスペクト比０～４）の範囲で制御することが好ましい。また、特に、輝度の均一化をさらに向上させるために、光源１１，１２と、拡散シート１５との間に、別の拡散板を、例えば、拡散剤を含む拡散板を配設した場合には、好ましくは０μｍから１５μｍ（アスペクト比０～３）の範囲、さらに好ましくは０μｍから１０μｍ（アスペクト比０～２）の範囲で制御されるのが好ましい。さらに、アレイ状のプリズム配列構造を有する光学シートと組み合わせて用いる場合、例えば、拡散シート１５の上方に、アレイ状のプリズム配列構造を有する光学シートを配設する場合は、０μｍから１０μｍ（アスペクト比０～２）の範囲で制御されるのが好ましい。 For example, if the pitch of the concavo-convex structure is 5 μm, the concavo-convex height is controlled within the range of 0 μm to 20 μm (aspect ratio of 0 to 4) from the viewpoint that moire does not occur even when the liquid crystal has a high definition (pixel narrowing). It is preferable. In particular, in order to further improve the uniformity of the brightness, when another diffusion plate, for example, a diffusion plate containing a diffusion agent is disposed between the light sources 11 and 12 and the diffusion sheet 15. It is preferably controlled in the range of 0 μm to 15 μm (aspect ratio 0 to 3), more preferably in the range of 0 μm to 10 μm (aspect ratio 0 to 2). Furthermore, when used in combination with an optical sheet having an arrayed prism arrangement structure, for example, when an optical sheet having an arrayed prism arrangement structure is disposed above the diffusion sheet 15, 0 μm to 10 μm (aspect ratio) It is preferably controlled in the range of 0-2).
　また、光源１１，１２の投影領域から光源１１，１２の間の投影領域における拡散角度の差、凹凸高さの差、及び位置による拡散角度・凹凸高さの変わり方は、輝度を均一化するために適宜調整することができる。 Further, the difference in the diffusion angle in the projection area between the light sources 11 and 12 and the projection area between the light sources 11 and 12, the difference in the uneven height, and how the diffusion angle and the uneven height change depending on the position make the luminance uniform. Therefore, it can adjust suitably.
　拡散板１４は、光を拡散させることのできるものであれば、様々なものを用いることができる。例えばポリスチレン、アクリル系樹脂、ポリカーボネート、シクロオレフィンポリマー等に、光を拡散させる効果がある有機ポリマーや無機微粒子を添加したものを用いることができる。これらの拡散板は、光を拡散させ、下部光源の光を均一化させる効果がある。また、前記拡散板１４は、表面に凹凸形状が形成されていても良い。これらには、必要に応じて、前記有機ポリマーや無機微粒子を添加したものを用いることができる。また、２成分以上の樹脂を混合し、延伸してシート状とした拡散板も用いることができる。 As the diffusion plate 14, various materials can be used as long as they can diffuse light. For example, polystyrene, acrylic resin, polycarbonate, cycloolefin polymer, or the like added with an organic polymer or inorganic fine particles having an effect of diffusing light can be used. These diffusers have the effect of diffusing light and making the light from the lower light source uniform. Further, the diffusion plate 14 may have an uneven shape on the surface. These may be added with the organic polymer or inorganic fine particles as required. A diffusion plate in which two or more components are mixed and stretched to form a sheet can also be used.
　以下に、本実施の形態で示す光源ユニットの具体的な構成について例をあげて、説明する。 Hereinafter, a specific configuration of the light source unit described in this embodiment will be described with an example.
　例えば、光源ユニットの構成として、図２３（ａ）から図２３（ｃ）に示す配設構成を採用することができる。 For example, as the configuration of the light source unit, the arrangement configuration shown in FIGS. 23 (a) to 23 (c) can be adopted.
　図２３（ａ）は、図１９（ｂ）に示す構成において、光源直上に配置される拡散板１４と拡散シート１５の間に、微細な凹凸構造が表面に形成された表面賦形型拡散シート１６を配置し、さらに拡散シート１５の直上に、前記表面賦形型拡散シート１６を配置してなる光線制御ユニットを示す。 FIG. 23A shows a surface-shaped diffusion sheet in which a fine uneven structure is formed on the surface between the diffusion plate 14 and the diffusion sheet 15 arranged immediately above the light source in the configuration shown in FIG. 19B. 16 shows a light beam control unit in which the surface-shaped diffusion sheet 16 is disposed immediately above the diffusion sheet 15.
　ここで、表面賦形型拡散シート１６としては、アクリル系樹脂の球状ビーズがポリエステル系樹脂、トリアセチルセルロース、或いはポリカーボネート等のシート上に塗布されたシートを用いることができる。また、表面賦形型拡散シート１６としては、紫外線硬化樹脂による微細な凹凸構造がポリエステル系樹脂、トリアセチルセルロース、或いはポリカーボネート等のシート上に転写されたシートを用いることができる。このような表面賦形型拡散シート１６は、光を拡散させ均一化させる効果とともに、拡散板１４で拡散された光を集光する機能を有する。これらの表面賦形型拡散シート１６と、拡散シート１５とを組み合わせて使用することにより、輝度むらを軽減し、光線制御ユニットの薄型化や光源数の削減を実現することができる。 Here, as the surface-shaped diffusion sheet 16, a sheet in which spherical beads of acrylic resin are coated on a sheet of polyester resin, triacetyl cellulose, polycarbonate, or the like can be used. Moreover, as the surface shaping type | mold diffusion sheet 16, the sheet | seat by which the fine uneven structure by the ultraviolet curable resin was transcribe | transferred on sheets, such as a polyester-type resin, a triacetyl cellulose, or a polycarbonate can be used. Such a surface shaping type diffusion sheet 16 has a function of condensing the light diffused by the diffusion plate 14 as well as the effect of diffusing and uniformizing the light. By using the surface-shaped diffusion sheet 16 and the diffusion sheet 15 in combination, luminance unevenness can be reduced, and the light beam control unit can be made thinner and the number of light sources can be reduced.
　図２３（ｂ）は、図１９（ｂ）に示す構成において、光源直上に配置される拡散板１４及び拡散シート１５の上方に、アレイ状のプリズム配列構造を有する光学シート１７と、微細な凹凸構造が表面に形成された表面賦形型拡散シート１６と、をこの順で配置してなる光線制御ユニットを示す。また図２３（ｃ）は、図１９（ｂ）に示す構成において、光源直上に配置される拡散板１４及び拡散シート１５の上方に、微細な凹凸構造が表面に形成された表面賦形型拡散シート１６と、アレイ状のプリズム配列構造を有する光学シート１７とを配置してなる光線制御ユニットを示す。 FIG. 23B shows an optical sheet 17 having an array-like prism arrangement structure and fine irregularities above the diffusion plate 14 and the diffusion sheet 15 arranged immediately above the light source in the configuration shown in FIG. 1 shows a light beam control unit in which a surface-shaped diffusion sheet 16 having a structure formed on the surface thereof is arranged in this order. FIG. 23C shows a surface-shaped diffusion in which a fine concavo-convex structure is formed on the surface above the diffusion plate 14 and the diffusion sheet 15 disposed immediately above the light source in the configuration shown in FIG. 1 shows a light beam control unit in which a sheet 16 and an optical sheet 17 having an arrayed prism arrangement structure are arranged.
　プリズムシート１７としては、表面に、断面形状が略三角形状、略台形状、略楕円状であるプリズム条列がアレイ状に配列しているような光学シートを用いることができる。前記断面形状の頂点を丸めた形状としたものも、耐擦傷性向上などの観点から、好ましく用いることができる。これらのプリズムシートとしては、紫外線硬化樹脂によるプリズム条列がポリエステル系樹脂、トリアセチルセルロース、或いはポリカーボネート等の基材シート上に転写された形態として用いることができる。このようなプリズムシート１７は再帰反射性を示すため、入射光を正面へ集光する機能を有する。このプリズムシートと、本発明の拡散シートとを組み合わせて使用することにより、輝度むらを軽減し、光源ユニットの薄型化や光源数の削減を実現することができる。 As the prism sheet 17, an optical sheet in which prism rows having a substantially triangular shape, a substantially trapezoidal shape, and a substantially elliptical shape are arrayed on the surface can be used. A shape obtained by rounding the apex of the cross-sectional shape can also be preferably used from the viewpoint of improving scratch resistance. These prism sheets can be used in a form in which a prism array made of an ultraviolet curable resin is transferred onto a base material sheet such as polyester resin, triacetyl cellulose, or polycarbonate. Since such a prism sheet 17 exhibits retroreflectivity, it has a function of collecting incident light to the front. By using this prism sheet in combination with the diffusion sheet of the present invention, luminance unevenness can be reduced, and the light source unit can be made thinner and the number of light sources can be reduced.
　図２４は、図２０（ｂ）に示す構成において、光源直上に配置される拡散板１４及び拡散シート１５の上方に、微細な凹凸構造が表面に形成された表面賦形型拡散シート１６を配置し、アレイ状のプリズム条列を有する光学シート１７と、反射型偏光シート１８と、をこの順で配置してなる光線制御ユニットを示す。 FIG. 24 shows a surface-shaped diffusion sheet 16 having a fine concavo-convex structure formed on the surface above the diffusion plate 14 and the diffusion sheet 15 disposed immediately above the light source in the configuration shown in FIG. A light beam control unit in which an optical sheet 17 having an array of prism rows and a reflective polarizing sheet 18 are arranged in this order is shown.
　反射型偏光シート１８としては、自然光又は偏光から直線偏光を分離する機能を有するシートを用いることができる。前記直線偏光を分離するシートとしては、例えば、軸方向で直交する直線偏光の一方を透過し、他方を反射するフィルム等が挙げられる。前記反射型偏光シートとしては、具体的には、複屈折位相差の大きい樹脂（ポリカーボネート、アクリル系樹脂、ポリエステル樹脂等）と、複屈折位相差の小さい樹脂（シクロオレフィンポリマー等)とを交互に多層積層し一軸延伸して得られるシートや、複屈折性のポリエステル樹脂を数百層積層した構造からなるシート（ＤＢＥＦ、３Ｍ（株）製）等を用いることができる。 As the reflective polarizing sheet 18, a sheet having a function of separating linearly polarized light from natural light or polarized light can be used. As a sheet | seat which isolate | separates the said linearly polarized light, the film etc. which permeate | transmit one of the linearly polarized light orthogonal to an axial direction, and reflect the other are mentioned, for example. Specifically, as the reflective polarizing sheet, a resin (polycarbonate, acrylic resin, polyester resin, etc.) having a large birefringence retardation and a resin (cycloolefin polymer, etc.) having a small birefringence retardation are alternately used. A sheet obtained by multilayer lamination and uniaxial stretching, a sheet having a structure in which several hundred layers of birefringent polyester resin are laminated (DBEF, manufactured by 3M Co., Ltd.), and the like can be used.
　他にも、光源ユニットの構成として、例えば、図２５、図２６に示す配設構成を採用することができる。 In addition, as the configuration of the light source unit, for example, the arrangement configuration shown in FIGS. 25 and 26 can be adopted.
　図２５（ａ）は、図１９（ａ）に示す構成において、光源１１と拡散シート１５の間に拡散板１４を配置し、さらに拡散シート１５の直上に、レンズシート１６を配置してなる光源ユニットを示す。また、図２５（ｂ）は、図１９（ａ）に示す構成において、拡散シート１５の上方に、拡散板１４、レンズシート１６の順で配置してなる光源ユニットを示す。 FIG. 25A shows a light source in which a diffusion plate 14 is disposed between the light source 11 and the diffusion sheet 15 and a lens sheet 16 is disposed immediately above the diffusion sheet 15 in the configuration shown in FIG. Indicates a unit. FIG. 25B shows a light source unit in which the diffusion plate 14 and the lens sheet 16 are arranged in this order above the diffusion sheet 15 in the configuration shown in FIG.
　図２５（ｃ）は、図１９（ａ）に示す構成において、光源１１と拡散シート１５の間に拡散板１４を配置し、さらに拡散シート１５の上方に、アレイ状のプリズム配列構造を有する光学シート（以下、プリズムシートと略記）１７、反射型偏光シート１８の順で配置してなる光源ユニットを示す。また、図２５（ｄ）は、図１９（ａ）に示す構成において、光源１１と拡散シート１５の間に拡散板１４を配置し、さらに拡散シート１５の上方に、プリズムシート１７のプリズム配列方向を直交させて２枚配置し、さらにその上方にレンズシート１６を配置してなる光源ユニットを示す。 FIG. 25C shows an optical system in which a diffusion plate 14 is arranged between the light source 11 and the diffusion sheet 15 in the configuration shown in FIG. 19A and an array-like prism arrangement structure is provided above the diffusion sheet 15. A light source unit in which a sheet (hereinafter abbreviated as a prism sheet) 17 and a reflective polarizing sheet 18 are arranged in this order is shown. FIG. 25D shows a configuration in which the diffusion plate 14 is disposed between the light source 11 and the diffusion sheet 15 in the configuration shown in FIG. A light source unit is shown in which two pieces are arranged so as to be orthogonal to each other and a lens sheet 16 is further disposed thereon.
　図２６（ａ）は、図１９（ａ）に示す構成において、光源１１と拡散シート１５の間に拡散板１４を配置し、さらに拡散シート１５の上方に、レンズシート１６、プリズムシート１７、及び反射型偏光シート１８をこの順で配置してなる光源ユニットを示す。また、図２６（ｂ）は、図１９（ａ）に示す構成において、拡散シート１５の上方に、拡散板１４、レンズシート１６、プリズムシート１７、及び反射型偏光シート１８をこの順で配置してなる光源ユニットを示す。 FIG. 26A shows a configuration in which the diffusion plate 14 is disposed between the light source 11 and the diffusion sheet 15 in the configuration shown in FIG. 19A, and the lens sheet 16, the prism sheet 17, and the A light source unit in which the reflective polarizing sheets 18 are arranged in this order is shown. In FIG. 26B, in the configuration shown in FIG. 19A, the diffusion plate 14, the lens sheet 16, the prism sheet 17, and the reflective polarizing sheet 18 are arranged in this order above the diffusion sheet 15. The light source unit is shown.
　次に、本発明の効果を明確にするために行った実施例について説明するが、本発明はこれらに限定されるものではない。 Next, examples carried out to clarify the effects of the present invention will be described, but the present invention is not limited to these examples.
　実施例１は、上記実施の形態１で示した内容に対応している。なお、実施例１に示される拡散角度は、微細な凹凸構造を有する面から入光させ、Photonで測定した角度を示している。例えば、５°は、どの方向のＦＷＨＭも、５°であることを表す。拡散角度分布については、拡散シートのｘ軸方向および／またはｙ軸方向に対して、２ｍｍ間隔でＦＷＨＭを測定し、分布図を作成した。以下実施例２、３の拡散角度分布についても同様に測定している。アスペクト比は、株式会社キーエンス製の超深度カラー３Ｄ形状測定顕微鏡（ＶＫ－９５００）を用いて、拡散シートのｘ軸方向および／またはｙ軸方向に対して、４ｍｍ間隔で測定し、アスペクト比分布を求めた。 Example 1 corresponds to the contents shown in the first embodiment. In addition, the diffusion angle shown in Example 1 is an angle measured by Photon after entering from a surface having a fine concavo-convex structure. For example, 5 ° indicates that the FWHM in any direction is 5 °. Regarding the diffusion angle distribution, FWHM was measured at intervals of 2 mm with respect to the x-axis direction and / or the y-axis direction of the diffusion sheet, and a distribution map was created. Hereinafter, the diffusion angle distributions of Examples 2 and 3 are similarly measured. The aspect ratio was measured at an interval of 4 mm with respect to the x-axis direction and / or y-axis direction of the diffusion sheet using an ultra-deep color 3D shape measurement microscope (VK-9500) manufactured by Keyence Corporation. Asked.
　実施例１－１、実施例１－２において、光学シートとして実施例において記載がないものについて、すなわち、反射シート、拡散板、表面賦形型拡散シート、アレイ状のプリズム配列構造を有する光学シート、反射型偏光シートについては、それぞれ、ポリエステル樹脂からなる白色反射シート（以下、ＲＳと略記）、ポリスチレンからなり、厚さ１．５ｍｍ、拡散剤濃度１３０００ｐｐｍの拡散板（以下、ＤＰと略記）、厚さ２５０μｍのＰＥＴ基材上に樹脂ビーズとバインダーが塗工された拡散シート（以下、ＤＳと略記）、厚さ２５０μｍのＰＥＴ基材上に頂角９０°、ピッチ５０μｍのプリズム条列がＵＶ硬化性樹脂によって賦形された光学シート（以下、プリズムシートと略記）、反射型偏光シート（以下、ＤＢＥＦと略記。３Ｍ社製）を用いた。 Examples 1-1 and 1-2 which are not described in the examples as optical sheets, that is, a reflection sheet, a diffusion plate, a surface-shaped diffusion sheet, and an optical sheet having an arrayed prism arrangement structure The reflective polarizing sheet is a white reflective sheet made of polyester resin (hereinafter abbreviated as RS), a diffuser plate made of polystyrene and having a thickness of 1.5 mm and a diffusing agent concentration of 13000 ppm (hereinafter abbreviated as DP), A diffusion sheet (hereinafter abbreviated as DS) in which resin beads and a binder are coated on a PET substrate having a thickness of 250 μm, and a prism array having an apex angle of 90 ° and a pitch of 50 μm is formed on the PET substrate having a thickness of 250 μm. An optical sheet (hereinafter abbreviated as prism sheet) shaped by a curable resin, a reflective polarizing sheet (hereinafter abbreviated as DBEF. 3M). Etsu Chemical Co., Ltd.) was used.
　実施例１－１については、光線制御ユニットの光源として、直径３．０ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．８ｍｍとし、前記光源同士の間隔ｐが２３．７ｍｍとなるように１６本配置して輝度評価用の光線制御ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光線制御ユニットから７５ｃｍ離して設置し、光線制御ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±１１．８ｍｍ分の輝度平均値で割り返した値の標準偏差（以下Ｓ．Ｄ．と記す）として輝度むらを求めた。 For Example 1-1, a CCFL light source having a diameter of 3.0 mmφ and a length of 710 mm was used as the light source of the light beam control unit. The CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and 16 are arranged so that the distance p between the light sources is 23.7 mm. A light control unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 75 cm away from the light control unit, and the average luminance value measured in the range of 20 mm × 190 mm in the center of the light control unit. Brightness. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value at each point by the average luminance value for ± 11.8 mm from each point ( In the following, luminance unevenness was obtained.
　ここで、輝度ムラの判定基準を下記のように、２段階（○、×）に分類した。
○：Ｓ．Ｄ．≦０．００４
×：０．００４＜Ｓ．Ｄ． Here, the luminance unevenness determination criteria were classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.004
X: 0.004 <S. D.
　（実施例１－１）
　図２６（ａ）に示すように、光源上方にＤＰ、本発明の拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例１－１の光線制御ユニットを構成した。本発明の拡散シートは、光源の投影領域の拡散角度が７０°、光源と光源の、中間点の投影領域の拡散角度が１°で、図２８（ｂ）に示すように拡散角度が変化している拡散シートを、凹凸面が出光面となるように用いた。ここで、ＣＣＦＬ光源とＤＰの入光面との距離ｚを４．５ｍｍとした。実施例１－１の光線制御ユニットにおける輝度むらを上記の方法で算出した。その結果を下記表１に示す。また、本発明の拡散シートについて、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）と、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）を下記表１に併記した。 Example 1-1
As shown in FIG. 26 (a), DP, the diffusion sheet of the present invention, DS, the prism sheet, and DBEF were arranged in this order above the light source to constitute the light control unit of Example 1-1. In the diffusion sheet of the present invention, the diffusion angle of the projection area of the light source is 70 °, the diffusion angle of the projection area of the intermediate point between the light source and the light source is 1 °, and the diffusion angle changes as shown in FIG. The diffusion sheet used was used so that the uneven surface became the light exit surface. Here, the distance z between the CCFL light source and the light incident surface of the DP was set to 4.5 mm. The luminance unevenness in the light beam control unit of Example 1-1 was calculated by the above method. The results are shown in Table 1 below. Further, for the diffusion sheet of the present invention, the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value of angles (Av2) is also shown in Table 1 below.
　また、この拡散シートのアスペクト比分布は図２８（ｂ）の曲線形状と同様の分布を示すもので、光源の投影領域で０．８、光源と光源の中間点の投影領域で０．１４であり、アスペクト比のピーク値とアスペクト比のボトム値との算術平均値（Ａｖ１）は０．４７、連続するアスペクト比のピーク値とアスペクト比のボトム値との間に分布する全測定点のアスペクト比の算術平均値（Ａｖ２）は０．３２である。 Further, the aspect ratio distribution of this diffusion sheet shows the same distribution as the curved shape of FIG. 28B, which is 0.8 in the projection area of the light source and 0.14 in the projection area of the intermediate point between the light source and the light source. Yes, the arithmetic average value (Av1) of the peak value of the aspect ratio and the bottom value of the aspect ratio is 0.47, and the aspect ratio of all measurement points distributed between the peak value of the continuous aspect ratio and the bottom value of the aspect ratio. The arithmetic average value (Av2) of the ratio is 0.32.
　実施例１－２については、光線制御ユニットの光源として、直径３．０ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．８ｍｍとし、前記光源同士の間隔ｐが４７．６ｍｍとなるように８本配置して輝度評価用の光線制御ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光線制御ユニットから７５ｃｍ離して設置し、光線制御ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±２３．８ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。 For Example 1-2, a CCFL light source having a diameter of 3.0 mmφ and a length of 710 mm was used as the light source of the light beam control unit. The CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and eight are arranged so that the distance p between the light sources is 47.6 mm. A light control unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 75 cm away from the light control unit, and the average luminance value measured in the range of 20 mm × 190 mm in the center of the light control unit. Brightness. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 23.8 mm from each point. Luminance unevenness was obtained.
　ここで、輝度ムラの判定基準を下記のように、２段階（○、×）に分類した。
○：Ｓ．Ｄ．≦０．００４
×：０．００４＜Ｓ．Ｄ． Here, the determination standard of luminance unevenness was classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.004
X: 0.004 <S. D.
　（実施例１－２）
　図２６（ａ）に示すように、光源上方にＤＰ、本発明の拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例１－２の光線制御ユニットを構成した。本発明の拡散シートは、光源の投影領域の拡散角度が３０°、光源と光源の、中間点の投影領域の拡散角度が１°で、図２８（ｃ）に示すように、拡散角度が変化する拡散シートを、凹凸面が出光面となるように用いた。ここで、ＣＣＦＬ光源とＤＰの入光面との距離ｚを４．５ｍｍとした。実施例１－２の光線制御ユニットにおける輝度むらを上記の方法で算出した。その結果を下記表１に示した。また、本発明の拡散シートについて、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）と、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）を下記表１に併記した。 Example 1-2
As shown in FIG. 26 (a), DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute the light control unit of Example 1-2. In the diffusion sheet of the present invention, the diffusion angle of the projection area of the light source is 30 °, the diffusion angle of the projection area of the intermediate point between the light source and the light source is 1 °, and the diffusion angle changes as shown in FIG. The diffusion sheet to be used was used so that the uneven surface becomes the light exit surface. Here, the distance z between the CCFL light source and the light incident surface of the DP was set to 4.5 mm. The luminance unevenness in the light beam control unit of Example 1-2 was calculated by the above method. The results are shown in Table 1 below. Further, for the diffusion sheet of the present invention, the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value of angles (Av2) is also shown in Table 1 below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　実施例１－３において、光学シートとして実施例において記載がないものについて、すなわち、反射シート、拡散板、表面賦形型拡散シート、アレイ状のプリズム配列構造を有する光学シート、反射型偏光シートについては、それぞれ、ポリエステル樹脂からなる白色反射シート（以下、ＲＳと略記）、ポリスチレンからなり、厚さ２．０ｍｍ、拡散剤濃度２００００ｐｐｍの拡散板（以下、ＤＰと略記）、厚さ２５０μｍのＰＥＴ基材上に樹脂ビーズとバインダーが塗工された拡散シート（以下、ＤＳと略記）、厚さ２５０μｍのＰＥＴ基材上に頂角９０°、ピッチ５０μｍのプリズム条列がＵＶ硬化性樹脂によって賦形された光学シート（以下、プリズムシートと略記）、反射型偏光シート（以下、ＤＢＥＦと略記。３Ｍ社製）を用いた。 In Example 1-3, the optical sheet that is not described in the examples, that is, the reflective sheet, the diffusion plate, the surface-shaped diffusion sheet, the optical sheet having the arrayed prism arrangement structure, and the reflective polarizing sheet Is a white reflective sheet (hereinafter abbreviated as RS) made of polyester resin, polystyrene, a diffusion plate (hereinafter abbreviated as DP) with a thickness of 2.0 mm and a diffusing agent concentration of 20000 ppm, and a PET base with a thickness of 250 μm. Diffusion sheet (hereinafter abbreviated as DS) with resin beads and binder coated on the material, prism array with apex angle of 90 ° and pitch of 50 μm is formed with UV curable resin on 250 μm thick PET substrate An optical sheet (hereinafter abbreviated as prism sheet) and a reflective polarizing sheet (hereinafter abbreviated as DBEF; manufactured by 3M Company) were used.
　実施例１－３については、光線制御ユニットの光源として、ＣＲＥＥ社製の３．５ｍｍ角、高さ２．０ｍｍの白色ＬＥＤ光源を用いた。前記光源の中心間距離をｘ軸方向、ｙ軸方向に３０．０ｍｍとして１０列ずつ、格子状に並べて配置し、光線制御ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光線制御ユニットから７０ｃｍ離して設置し、光線制御ユニットの中心部１２０ｍｍ×１２０ｍｍの範囲で測定した平均輝度値を輝度とした。 For Example 1-3, a white LED light source of 3.5 mm square and 2.0 mm height made by CREE was used as the light source of the light control unit. The distance between the centers of the light sources was set to 30.0 mm in the x-axis direction and the y-axis direction, and 10 rows were arranged in a grid to arrange a light control unit. Luminance and luminance unevenness were measured using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed at a distance of 70 cm from the light control unit, and an average luminance value measured in a range of 120 mm × 120 mm at the center of the light control unit. Brightness.
　輝度むらは、ｘ軸方向及びｙ軸方向の２方向について算出した値の平均値とした。まず、ｘ軸（１２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±１２ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。同様に、ｙ軸（１００ｍｍ）方向の平均輝度値を求め、ｘ軸方向について、各々の点の輝度値を各々の点から±１５ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。最後に、ｘ軸方向の標準偏差とｙ軸方向の標準偏差を平均した値を、光線制御ユニットの輝度むらとした。なお、ＬＥＤ光源は点光源であるので、図２（ｂ）のように、隣接する光源の直線距離が最大となるような線（図２（ｂ）における破線）上において、拡散角度の分布を考えた。 The luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction. First, an average luminance value in the x-axis (120 mm) direction is obtained, and luminance unevenness is obtained as a standard deviation of values obtained by dividing the luminance value of each point by the average luminance value of ± 12 mm from each point in the y-axis direction. Asked. Similarly, an average luminance value in the y-axis (100 mm) direction is obtained, and luminance unevenness is obtained as a standard deviation of values obtained by dividing the luminance value of each point by the average luminance value of ± 15 mm from each point in the x-axis direction. Asked. Finally, a value obtained by averaging the standard deviation in the x-axis direction and the standard deviation in the y-axis direction was used as the luminance unevenness of the light control unit. Since the LED light source is a point light source, as shown in FIG. 2 (b), the diffusion angle distribution is distributed on a line (dashed line in FIG. 2 (b)) that maximizes the linear distance between adjacent light sources. Thought.
　ここで、輝度ムラの判定基準を下記のように、２段階（○、×）に分類した。
○：Ｓ．Ｄ．≦０．００５
×：０．００５＜Ｓ．Ｄ． Here, the determination standard of luminance unevenness was classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.005
X: 0.005 <S. D.
　（実施例１－３）
　図２４（ａ）に示すように、光源上方にＤＰ、本発明の拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例１－３の光線制御ユニットを構成した。本発明の拡散シートは、光源の投影領域の拡散角度が６０°、光源と光源の、中間点の投影領域の拡散角度が２０°で、図２８（ａ）に示すように拡散角度が変化している拡散シートを、凹凸面が出光面となるように用いた。ここで、ＲＳとＤＰの入光面との距離ｈを１６．０ｍｍとした。実施例１－３の光線制御ユニットにおける輝度むらを上記の方法で算出した。その結果を下記表２に示す。また、本発明の拡散シートについて、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）と、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）を下記表２に併記した。 (Example 1-3)
As shown in FIG. 24A, DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute the light control unit of Example 1-3. In the diffusion sheet of the present invention, the diffusion angle of the projection area of the light source is 60 °, the diffusion angle of the projection area of the intermediate point between the light source and the light source is 20 °, and the diffusion angle changes as shown in FIG. The diffusion sheet used was used so that the uneven surface became the light exit surface. Here, the distance h between the light incident surface of RS and DP was set to 16.0 mm. The luminance unevenness in the light beam control unit of Example 1-3 was calculated by the above method. The results are shown in Table 2 below. Further, for the diffusion sheet of the present invention, the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value of angles (Av2) is also shown in Table 2 below.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　実施例１－４、実施例１－５において、光学シートとして実施例において記載がないものについて、すなわち、反射シート、拡散板、表面賦形型拡散シート、アレイ状のプリズム配列構造を有する光学シート、反射型偏光シートについては、それぞれ、ポリエステル樹脂からなる白色反射シート（以下、ＲＳと略記）、ポリスチレンからなり、厚さ１．５ｍｍ、拡散剤濃度１３０００ｐｐｍの拡散板（以下、ＤＰと略記）、厚さ２５０μｍのＰＥＴ基材上に樹脂ビーズとバインダーが塗工された拡散シート（以下、ＤＳと略記）、厚さ２５０μｍのＰＥＴ基材上に半球状のレンズがＵＶ硬化性樹脂によって賦形された光学シート（以下、ＭＬＦと略記）、厚さ２５０μｍのＰＥＴ基材上に頂角９０°、ピッチ５０μｍのプリズム条列がＵＶ硬化性樹脂によって賦形された光学シート（以下、プリズムシートと略記）、反射型偏光シート（以下、ＤＢＥＦと略記。３Ｍ社製）を用いた。 In Examples 1-4 and 1-5, optical sheets that are not described in the examples, that is, a reflection sheet, a diffusion plate, a surface-shaped diffusion sheet, and an optical sheet having an arrayed prism arrangement structure The reflective polarizing sheet is a white reflective sheet made of polyester resin (hereinafter abbreviated as RS), a diffuser plate made of polystyrene and having a thickness of 1.5 mm and a diffusing agent concentration of 13000 ppm (hereinafter abbreviated as DP), A diffusion sheet (hereinafter abbreviated as DS) in which resin beads and a binder are coated on a PET substrate having a thickness of 250 μm, and a hemispherical lens is formed by a UV curable resin on a PET substrate having a thickness of 250 μm. An optical sheet (hereinafter abbreviated as MLF), a prism array with an apex angle of 90 ° and a pitch of 50 μm on a 250 μm thick PET substrate is UV cured. An optical sheet (hereinafter abbreviated as “prism sheet”) and a reflective polarizing sheet (hereinafter abbreviated as “DBEF”; manufactured by 3M) were used.
　実施例１－４については、光線制御ユニットの光源として、直径３．０ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．８ｍｍとし、前記光源同士の間隔ｐが２３．７ｍｍとなるように１６本配置して輝度評価用の光線制御ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光線制御ユニットから７５ｃｍ離して設置し、光線制御ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±１１．８ｍｍ分の輝度平均値で割り返した値の標準偏差（以下Ｓ．Ｄ．と記す）として輝度むらを求めた。 For Example 1-4, a CCFL light source having a diameter of 3.0 mmφ and a length of 710 mm was used as the light source of the light beam control unit. The CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and 16 are arranged so that the distance p between the light sources is 23.7 mm. A light control unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 75 cm away from the light control unit, and the average luminance value measured in the range of 20 mm × 190 mm in the center of the light control unit. Brightness. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value at each point by the average luminance value for ± 11.8 mm from each point ( In the following, luminance unevenness was obtained.
　ここで、輝度ムラの判定基準を下記のように、２段階（○、×）に分類した。
○：Ｓ．Ｄ．≦０．００４
×：０．００４＜Ｓ．Ｄ． Here, the determination standard of luminance unevenness was classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.004
X: 0.004 <S. D.
　（実施例１－４）
　図２６（ａ）に示すように、光源上方にＤＰ、本発明の拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例１－４の光線制御ユニットを構成した。本発明の拡散シートは、光源の投影領域の拡散角度が７０°、光源と光源の、中間点の投影領域の拡散角度が１°で、図２９（ａ）に示すように拡散角度が変化している拡散シートを、凹凸面が出光面となるように用いた。ここで、ＣＣＦＬ光源とＤＰの入光面との距離ｚを４．５ｍｍとした。実施例１－４の光線制御ユニットにおける輝度むらを上記の方法で算出した。その結果を下記表３に示す。また、本発明の拡散シートについて、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）と、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）を下記表３に併記した。 (Example 1-4)
As shown in FIG. 26 (a), DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute the light control unit of Example 1-4. In the diffusion sheet of the present invention, the diffusion angle of the projection area of the light source is 70 °, the diffusion angle of the projection area of the intermediate point between the light source and the light source is 1 °, and the diffusion angle changes as shown in FIG. The diffusion sheet used was used so that the uneven surface became the light exit surface. Here, the distance z between the CCFL light source and the light incident surface of the DP was set to 4.5 mm. The luminance unevenness in the light beam control unit of Example 1-4 was calculated by the above method. The results are shown in Table 3 below. Further, for the diffusion sheet of the present invention, the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value (Av2) of the angle is also shown in Table 3 below.
　実施例１－５については、光線制御ユニットの光源として、直径３．０ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．８ｍｍとし、前記光源同士の間隔ｐが４７．６ｍｍとなるように８本配置して輝度評価用の光線制御ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光線制御ユニットから７５ｃｍ離して設置し、光線制御ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±２３．８ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。 For Example 1-5, a CCFL light source having a diameter of 3.0 mmφ and a length of 710 mm was used as the light source of the light beam control unit. The CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and eight are arranged so that the distance p between the light sources is 47.6 mm. A light control unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 75 cm away from the light control unit, and the average luminance value measured in the range of 20 mm × 190 mm in the center of the light control unit. Brightness. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 23.8 mm from each point. Luminance unevenness was obtained.
　ここで、輝度ムラの判定基準を下記のように、２段階（○、×）に分類した。
○：Ｓ．Ｄ．≦０．００４
×：０．００４＜Ｓ．Ｄ． Here, the determination standard of luminance unevenness was classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.004
X: 0.004 <S. D.
　（実施例１－５）
　光源上方にＤＰ、本発明の拡散シート、ＭＬＦ、ＭＬＦ、をこの順で配置し、実施例１－５の光線制御ユニットを構成した。本発明の拡散シートは、光源の投影領域の拡散角度が５９°、光源と光源の、中間点の投影領域の拡散角度が２５°で、図２９（ｂ）に示すように拡散角度が変化している拡散シートを、凹凸面が出光面となるように用いた。ここで、ＣＣＦＬ光源とＤＰの入光面との距離ｚを４．５ｍｍとした。実施例１－５の光線制御ユニットにおける輝度むらを上記の方法で算出した。その結果を下記表３に示した。また、本発明の拡散シートについて、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）と、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）を下記表３に併記した。 (Example 1-5)
DP, the diffusion sheet of the present invention, MLF, and MLF were disposed in this order above the light source to constitute the light control unit of Example 1-5. In the diffusion sheet of the present invention, the diffusion angle of the projection area of the light source is 59 °, the diffusion angle of the projection area of the intermediate point between the light source and the light source is 25 °, and the diffusion angle changes as shown in FIG. The diffusion sheet used was used so that the uneven surface became the light exit surface. Here, the distance z between the CCFL light source and the light incident surface of the DP was set to 4.5 mm. The luminance unevenness in the light beam control unit of Example 1-5 was calculated by the above method. The results are shown in Table 3 below. Further, for the diffusion sheet of the present invention, the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value (Av2) of the angle is also shown in Table 3 below.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　実施例１－６、１－７、１－８において、光学シートとして実施例において記載がないものについて、すなわち、反射シート、拡散板、表面賦形型拡散シート、マイクロレンズシート、アレイ状のプリズム配列構造を有する光学シート、反射型偏光シートについては、それぞれ、ポリエステル樹脂からなる白色反射シート（以下、ＲＳと略記）、ポリスチレンからなり、厚さ２．０ｍｍ、拡散剤濃度２００００ｐｐｍの拡散板（以下、ＤＰと略記）、厚さ２５０μｍのＰＥＴ基材上に樹脂ビーズとバインダーが塗工された拡散シート（以下、ＤＳと略記）、厚さ２５０μｍのＰＥＴ基材上に半球状のレンズがＵＶ硬化性樹脂によって賦形された光学シート（以下、ＭＬＦと略記）、厚さ２５０μｍのＰＥＴ基材上に頂角９０°、ピッチ５０μｍのプリズム条列がＵＶ硬化性樹脂によって賦形された光学シート（以下、プリズムシートと略記）、反射型偏光シート（以下、ＤＢＥＦと略記。３Ｍ社製）を用いた。 In Examples 1-6, 1-7, and 1-8, optical sheets that are not described in the examples, that is, a reflection sheet, a diffusion plate, a surface-shaped diffusion sheet, a microlens sheet, and an array prism The optical sheet and the reflective polarizing sheet having an array structure are respectively a white reflective sheet made of polyester resin (hereinafter abbreviated as RS) and a polystyrene, a diffusion plate having a thickness of 2.0 mm and a diffusing agent concentration of 20000 ppm. Abbreviated as DP), a diffusion sheet (hereinafter abbreviated as DS) in which resin beads and a binder are coated on a PET substrate having a thickness of 250 μm, and a hemispherical lens on a PET substrate having a thickness of 250 μm is UV cured. Optical sheet (hereinafter abbreviated as MLF) formed by a conductive resin, apex angle 90 °, pitch 50 μm on a 250 μm thick PET base material An optical sheet (hereinafter abbreviated as “prism sheet”) and a reflective polarizing sheet (hereinafter abbreviated as “DBEF”, manufactured by 3M) were used.
　実施例１－６については、光線制御ユニットの光源として、ＣＲＥＥ社製の３．５ｍｍ角、高さ２．０ｍｍの白色ＬＥＤ光源を用いた。このＬＥＤを図３０（ａ）に示すような千鳥格子状に配列した（aおよびbは光源の中心間距離）。ＬＥＤはＸ方向、Ｙ方向に１０個ずつ並べて配置し、光線制御ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光線制御ユニットから７０ｃｍ離して設置し、光線制御ユニットの中心部１２０ｍｍ×１２０ｍｍの範囲で測定した平均輝度値を輝度とした。 For Example 1-6, a white LED light source of 3.5 mm square and 2.0 mm height manufactured by CREE was used as the light source of the light control unit. The LEDs are arranged in a staggered pattern as shown in FIG. 30A (a and b are distances between the centers of the light sources). Ten LEDs were arranged side by side in the X and Y directions to produce a light beam control unit. Luminance and luminance unevenness were measured using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed at a distance of 70 cm from the light control unit, and an average luminance value measured in a range of 120 mm × 120 mm at the center of the light control unit. Brightness.
　輝度むらは、ｘ軸方向及びｙ軸方向の２方向について算出した値の平均値とした。まず、ｘ軸（１２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±２０．８ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。同様に、ｙ軸（１２０ｍｍ）方向の平均輝度値を求め、ｘ軸方向について、各々の点の輝度値を各々の点から±１５．２ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。最後に、ｘ軸方向の標準偏差とｙ軸方向の標準偏差を平均した値を、光線制御ユニットの輝度むらとした。なお、ＬＥＤ光源は点光源であるので、図２（ｂ）のように、隣接する光源の直線距離が最大となるような線（図２（ｂ）における破線）上において、拡散角度の分布を考えた。 The luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction. First, an average luminance value in the x-axis (120 mm) direction is obtained, and in the y-axis direction, luminance is obtained as a standard deviation of values obtained by dividing the luminance value at each point by the average luminance value for ± 20.8 mm from each point. I asked for unevenness. Similarly, the average luminance value in the y-axis (120 mm) direction is obtained, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 15.2 mm from each point in the x-axis direction. Luminance unevenness was obtained. Finally, a value obtained by averaging the standard deviation in the x-axis direction and the standard deviation in the y-axis direction was used as the luminance unevenness of the light control unit. Since the LED light source is a point light source, as shown in FIG. 2 (b), the diffusion angle distribution is distributed on a line (dashed line in FIG. 2 (b)) that maximizes the linear distance between adjacent light sources. Thought.
　実施例１－７については、光線制御ユニットの光源として、ＣＲＥＥ社製の３．５ｍｍ角、高さ２．０ｍｍの白色ＬＥＤ光源を用いた。このＬＥＤを図３０（ｂ）に示すような千鳥格子状に配列した（aおよびbは光源の中心間距離）。ＬＥＤはＸ方向、Ｙ方向に１０個ずつ並べて配置し、光線制御ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光線制御ユニットから７０ｃｍ離して設置し、光線制御ユニットの中心部１２０ｍｍ×１２０ｍｍの範囲で測定した平均輝度値を輝度とした。 For Example 1-7, a white LED light source of 3.5 mm square and a height of 2.0 mm manufactured by CREE was used as the light source of the light control unit. The LEDs were arranged in a staggered pattern as shown in FIG. 30B (a and b are distances between the centers of the light sources). Ten LEDs were arranged side by side in the X and Y directions to produce a light beam control unit. Luminance and luminance unevenness were measured using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed at a distance of 70 cm from the light control unit, and an average luminance value measured in a range of 120 mm × 120 mm at the center of the light control unit. Brightness.
　輝度むらは、ｘ軸方向及びｙ軸方向の２方向について算出した値の平均値とした。まず、ｘ軸（１２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±２５．２ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。同様に、ｙ軸（１２０ｍｍ）方向の平均輝度値を求め、ｘ軸方向について、各々の点の輝度値を各々の点から±１７．２ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。最後に、ｘ軸方向の標準偏差とｙ軸方向の標準偏差を平均した値を、光線制御ユニットの輝度むらとした。なお、ＬＥＤ光源は点光源であるので、図２（ｂ）のように、隣接する光源の直線距離が最大となるような線（図２（ｂ）における破線）上において、拡散角度の分布を考えた。 The luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction. First, an average luminance value in the x-axis (120 mm) direction is obtained, and in the y-axis direction, luminance is obtained as a standard deviation of values obtained by dividing the luminance value at each point by the average luminance value for ± 25.2 mm from each point. I asked for unevenness. Similarly, the average luminance value in the y-axis (120 mm) direction is obtained, and the standard deviation of the value obtained by dividing the luminance value of each point by the luminance average value for ± 17.2 mm from each point in the x-axis direction. Luminance unevenness was obtained. Finally, a value obtained by averaging the standard deviation in the x-axis direction and the standard deviation in the y-axis direction was used as the luminance unevenness of the light control unit. Since the LED light source is a point light source, as shown in FIG. 2 (b), the diffusion angle distribution is distributed on a line (dashed line in FIG. 2 (b)) that maximizes the linear distance between adjacent light sources. Thought.
　実施例１－８については、光線制御ユニットの光源として、ＣＲＥＥ社製の３．５ｍｍ角、高さ２．０ｍｍの白色ＬＥＤ光源を用いた。このＬＥＤを図３０（ｃ）に示すような正方格子状に配列した（aおよびbは光源の中心間距離）。ＬＥＤはＸ方向、Ｙ方向に１０個ずつ並べて配置し、光線制御ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光線制御ユニットから７０ｃｍ離して設置し、光線制御ユニットの中心部１２０ｍｍ×１２０ｍｍの範囲で測定した平均輝度値を輝度とした。 In Example 1-8, a white LED light source of 3.5 mm square and 2.0 mm height manufactured by CREE was used as the light source of the light control unit. The LEDs were arranged in a square lattice pattern as shown in FIG. 30C (a and b are distances between the centers of the light sources). Ten LEDs were arranged side by side in the X and Y directions to produce a light beam control unit. Luminance and luminance unevenness were measured using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed at a distance of 70 cm from the light control unit, and an average luminance value measured in a range of 120 mm × 120 mm at the center of the light control unit. Brightness.
　輝度むらは、ｘ軸方向及びｙ軸方向の２方向について算出した値の平均値とした。まず、ｘ軸（１２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±２４．７５ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。同様に、ｙ軸（１２０ｍｍ）方向の平均輝度値を求め、ｘ軸方向について、各々の点の輝度値を各々の点から±２７．５ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。最後に、ｘ軸方向の標準偏差とｙ軸方向の標準偏差を平均した値を、光線制御ユニットの輝度むらとした。なお、ＬＥＤ光源は点光源であるので、図２（ｂ）のように、隣接する光源の直線距離が最大となるような線（図２（ｂ）における破線）上において、拡散角度の分布を考えた。 The luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction. First, an average luminance value in the x-axis (120 mm) direction is obtained, and in the y-axis direction, the luminance as a standard deviation of a value obtained by dividing the luminance value at each point by the average luminance value for ± 24.75 mm from each point. I asked for unevenness. Similarly, the average luminance value in the y-axis (120 mm) direction is obtained, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 27.5 mm from each point in the x-axis direction. Luminance unevenness was obtained. Finally, a value obtained by averaging the standard deviation in the x-axis direction and the standard deviation in the y-axis direction was used as the luminance unevenness of the light control unit. Since the LED light source is a point light source, as shown in FIG. 2 (b), the diffusion angle distribution is distributed on a line (dashed line in FIG. 2 (b)) that maximizes the linear distance between adjacent light sources. Thought.
　ここで、輝度ムラの判定基準を下記のように、２段階（○、×）に分類した。
○：Ｓ．Ｄ．≦０．００５
×：０．００５＜Ｓ．Ｄ． Here, the determination standard of luminance unevenness was classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.005
X: 0.005 <S. D.
　（実施例１－６）
　光源上方にＤＰ、本発明の拡散シート、ＤＳ、ＤＳ、ＤＢＥＦと、をこの順で配置し、実施例１－６の光線制御ユニットを構成した。本発明の拡散シートは、光源の投影領域の拡散角度が８２°、光源と光源の、中間点の投影領域の拡散角度が１９°で、図３１（ａ）に示すように拡散角度が変化する拡散シートを、凹凸面が出光面となるように用いた。ここで、ＲＳとＤＰの入光面との距離ｈを１７．０ｍｍとした。実施例１－６の光線制御ユニットにおける輝度むらを上記の方法で算出した。その結果を下記表４に示す。また、本発明の拡散シートについて、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）と、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）を下記表４に示した。 (Example 1-6)
DP, the diffusion sheet of the present invention, DS, DS, and DBEF were arranged in this order above the light source to constitute the light control unit of Example 1-6. In the diffusion sheet of the present invention, the diffusion angle of the projection area of the light source is 82 °, the diffusion angle of the projection area of the intermediate point between the light source and the light source is 19 °, and the diffusion angle changes as shown in FIG. The diffusion sheet was used so that the uneven surface becomes the light exit surface. Here, the distance h between the light incident surface of RS and DP was set to 17.0 mm. The luminance unevenness in the light beam control unit of Example 1-6 was calculated by the above method. The results are shown in Table 4 below. Further, for the diffusion sheet of the present invention, the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value (Av2) of the angle is shown in Table 4 below.
（実施例１－７）
　光源上方にＤＰ、本発明の拡散シート、ＭＬＦ、ＭＬＦ、ＤＢＥＦと、をこの順で配置し、実施例１－７の光線制御ユニットを構成した。本発明の拡散シートは、光源の投影領域の拡散角度が６４°、光源と光源の、中間点の投影領域の拡散角度が８°で、図３１（ｂ）に示すように拡散角度が変化する拡散シートを、凹凸面が出光面となるように用いた。ここで、ＲＳとＤＰの入光面との距離ｈを２０．０ｍｍとした。実施例１－７の光線制御ユニットにおける輝度むらを上記の方法で算出した。その結果を下記表４に示す。また、本発明の拡散シートについて、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）と、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）を下記表４に併記した。 (Example 1-7)
DP, the diffusion sheet of the present invention, MLF, MLF, and DBEF were arranged in this order above the light source to constitute the light control unit of Example 1-7. In the diffusion sheet of the present invention, the diffusion angle of the projection area of the light source is 64 °, the diffusion angle of the projection area of the intermediate point between the light source and the light source is 8 °, and the diffusion angle changes as shown in FIG. The diffusion sheet was used so that the uneven surface becomes the light exit surface. Here, the distance h between the light incident surface of RS and DP was set to 20.0 mm. The luminance unevenness in the light beam control unit of Example 1-7 was calculated by the above method. The results are shown in Table 4 below. Further, for the diffusion sheet of the present invention, the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value (Av2) of the angle is also shown in Table 4 below.
（実施例１－８）
　図２４に示すように光源上方にＤＰ、本発明の拡散シート、ＭＬＦ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例１－８の光線制御ユニットを構成した。本発明の拡散シートは、光源の投影領域の拡散角度が６２°、光源と光源の、中間点の投影領域の拡散角度が１２°で、図３１（ｃ）に示すように拡散角度が変化する拡散シートを、凹凸面が出光面となるように用いた。ここで、ＲＳとＤＰの入光面との距離ｈを４０．０ｍｍとした。実施例１－８の光線制御ユニットにおける輝度むらを上記の方法で算出した。その結果を下記表４に示す。また、本発明の拡散シートについて、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）と、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）を下記表４に併記した。 (Example 1-8)
As shown in FIG. 24, the DP, the diffusion sheet of the present invention, the MLF, the prism sheet, and the DBEF are arranged in this order above the light source to constitute the light control unit of Example 1-8. In the diffusion sheet of the present invention, the diffusion angle of the projection area of the light source is 62 °, the diffusion angle of the projection area of the intermediate point between the light source and the light source is 12 °, and the diffusion angle changes as shown in FIG. The diffusion sheet was used so that the uneven surface becomes the light exit surface. Here, the distance h between the light incident surface of RS and DP was 40.0 mm. The luminance unevenness in the light beam control unit of Example 1-8 was calculated by the above method. The results are shown in Table 4 below. Further, for the diffusion sheet of the present invention, the diffusion of all measurement points distributed between the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value and the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value (Av2) of the angle is also shown in Table 4 below.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表４より、本発明の拡散シートは、拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）よりも、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）が低いことにより輝度ムラを抑制することが可能となり、光源ユニットを薄型化できることがわかる。 From Table 4, the diffusion sheet of the present invention has all measurements distributed between the continuous diffusion angle peak value and the diffusion angle bottom value, rather than the arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value. It can be seen that when the arithmetic average value (Av2) of the point diffusion angle is low, the luminance unevenness can be suppressed and the light source unit can be thinned.
　実施例２に示される拡散角度は、拡散シート凹凸面を入射面とし、前記凹凸面の法線方向に入射した光に対する透過光強度の角度分布を、変角光度計で測定した結果から算出している。例えば、５°は、どの方向の拡散角度も、５°であることを表す。 The diffusion angle shown in Example 2 is calculated from the result of measuring the angle distribution of the transmitted light intensity with respect to the light incident in the normal direction of the concavo-convex surface with the diffusing surface of the diffusing sheet as the incident surface, using a goniophotometer. ing. For example, 5 ° indicates that the diffusion angle in any direction is 5 °.
　実施例及び比較例に記載した、シート面内において拡散角度分布を有するような拡散シートは、前記シート面内の一方向で拡散角度が周期的に変化し、さらに、前記拡散シートを含む光源ユニットにおいて、ＣＣＦＬ光源の長手方向と直交する方向と、前記拡散角度が周期的に変化する方向を一致させている。また、光源からの照度分布に対応するように前記拡散シート面内における拡散角度分布を設計し、照度が高い領域には前記拡散シートの拡散角度が高い領域を配置して用いた。 The diffusion sheet having a diffusion angle distribution in the sheet surface described in the examples and comparative examples, the diffusion angle periodically changes in one direction in the sheet surface, and further includes a light source unit including the diffusion sheet , The direction orthogonal to the longitudinal direction of the CCFL light source is matched with the direction in which the diffusion angle periodically changes. Moreover, the diffusion angle distribution in the surface of the diffusion sheet was designed so as to correspond to the illuminance distribution from the light source, and a region where the diffusion angle of the diffusion sheet was high was arranged and used in a region where the illuminance was high.
　実施例２－１から実施例２－２、比較例２－１において、光学シートとして実施例において記載がないものについて、すなわち、反射シート、拡散板、レンズシート、プリズムシート、反射型偏光シートについては、それぞれ、ポリエステル樹脂からなる白色反射シート（以下、ＲＳと略記）、ポリスチレンからなり、粒径２μｍ、真比重１．３５のシリコーン微粒子を拡散剤として１３０００ｐｐｍ含有する、厚さ１．５ｍｍの拡散板（以下、ＤＰと略記）、厚さ２５０μｍのＰＥＴ基材上に樹脂ビーズとバインダーが塗工されたレンズシート（以下、ＤＳと略記）、厚さ２５０μｍのＰＥＴ基材上に頂角９０°、ピッチ５０μｍのプリズム条列がＵＶ硬化性樹脂によって賦形されたプリズムシート（以下、プリズムシートと略記）、反射型偏光シート（以下、ＤＢＥＦと略記。３Ｍ社製）を用いた。 In Examples 2-1 to 2-2 and Comparative Example 2-1, optical sheets that are not described in the examples, that is, a reflective sheet, a diffuser plate, a lens sheet, a prism sheet, and a reflective polarizing sheet are used. Are respectively a white reflective sheet (hereinafter abbreviated as RS) made of polyester resin, polystyrene, and 13,000 ppm of silicon fine particles having a particle size of 2 μm and a true specific gravity of 1.35 as a diffusing agent, and having a thickness of 1.5 mm. Plate (hereinafter abbreviated as DP), lens sheet (hereinafter abbreviated as DS) in which resin beads and binder are coated on a PET substrate having a thickness of 250 μm, apex angle 90 ° on a PET substrate having a thickness of 250 μm Prism sheet (hereinafter abbreviated as “prism sheet”) in which prism rows with a pitch of 50 μm are shaped by a UV curable resin, reflective type A polarizing sheet (hereinafter abbreviated as DBEF, manufactured by 3M) was used.
　実施例２－１から実施例２－３、比較例２－１については、光源ユニットの光源として、直径３．０ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．８ｍｍとし、前記光源同士の間隔ｐが２３．７ｍｍとなるように１６本配置して輝度評価用の光源ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光源ユニットから７５ｃｍ離して設置し、光源ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±１１．８ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。
　ここで、輝度むらの判定基準を下記のように３段階（◎、○、×）に分類した。
◎：Ｓ．Ｄ．　≦０．００２
○：０．００２＜Ｓ．Ｄ．　≦０．００４
×：０．００４＜Ｓ．Ｄ． In Examples 2-1 to 2-3 and Comparative Example 2-1, a CCFL light source having a diameter of 3.0 mmφ and a length of 710 mm was used as the light source of the light source unit. The CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and 16 are arranged so that the distance p between the light sources is 23.7 mm. A light source unit was prepared. The brightness and brightness unevenness were measured by using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed 75 cm away from the light source unit, and the average brightness value measured in the range of 20 mm × 190 mm in the center of the light source unit as brightness. did. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 11.8 mm from each point in the y-axis direction. Luminance unevenness was obtained.
Here, the judgment criteria for luminance unevenness were classified into the following three levels (◎, ○, ×).
A: S. D. ≦ 0.002
A: 0.002 <S. D. ≦ 0.004
X: 0.004 <S. D.
　実施例２－１及び実施例２－２、比較例２－１については、図２５（ａ）に示すような基本構成を採る光源ユニットにおいて評価を行った。 Example 2-1 and Example 2-2 and Comparative Example 2-1 were evaluated in a light source unit having a basic configuration as shown in FIG.
　（実施例２－１）
　図２６（ａ）に示すように、光源上方にＤＰ、本発明の拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例２－１の光源ユニットを構成した。本発明の拡散シートは、拡散角度の最大値が７０°、最小値が１°で、拡散角度差が６９°であり、図１０（ｂ）に示すように、前記拡散シート面内で拡散角度が分布している拡散シートを、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源とＤＰの入光面との距離ｈを４．５ｍｍとした。実施例２－１の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表５に示す。 Example 2-1
As shown in FIG. 26 (a), the light source unit of Example 2-1 was configured by arranging DP, the diffusion sheet of the present invention, DS, the prism sheet, and DBEF in this order above the light source. The diffusion sheet of the present invention has a maximum diffusion angle of 70 °, a minimum value of 1 °, and a diffusion angle difference of 69 °. As shown in FIG. 10B, the diffusion angle is within the plane of the diffusion sheet. The diffusion sheet in which is distributed is disposed so that the uneven surface becomes the light exit surface. Here, the distance h between the CCFL light source and the light incident surface of the DP was 4.5 mm. The luminance in the light source unit of Example 2-1 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 5 below.
　（実施例２－２）
　図２５（ｃ）に示すように、光源上方に、レンチキュラーレンズが賦形された拡散板、本発明の拡散シート、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例２－２の光源ユニットを構成した。実施例２－２において用いた拡散板は厚さ１．５ｍｍのポリスチレン製で、内部に２０００ｐｐｍの拡散剤を含有し、出光面に高さ１３０μｍ、ピッチ３２０μｍのレンチキュラーレンズが、ＣＣＦＬ光源の長手方向と平行方向に多数形成されている。本発明の拡散シートは、拡散角度の最大値が８０°、拡散角度の最小値が４０°で、拡散角度差は４０°であり、図１０（ｂ）に示すように、前記拡散シート面内で拡散角度が分布している拡散シートを、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源と拡散板の入光面との距離ｈを４．５ｍｍとした。実施例２－２の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表５に併記する。 (Example 2-2)
As shown in FIG. 25 (c), a diffusion plate formed with a lenticular lens, the diffusion sheet of the present invention, a prism sheet, and DBEF are arranged in this order above the light source, and the light source of Example 2-2 Configured the unit. The diffusion plate used in Example 2-2 is made of polystyrene having a thickness of 1.5 mm, contains 2000 ppm of a diffusing agent inside, a lenticular lens having a height of 130 μm and a pitch of 320 μm is formed in the longitudinal direction of the CCFL light source. Are formed in parallel with each other. In the diffusion sheet of the present invention, the maximum value of the diffusion angle is 80 °, the minimum value of the diffusion angle is 40 °, and the difference in diffusion angle is 40 °. As shown in FIG. The diffusion sheet in which the diffusion angle is distributed is arranged so that the uneven surface becomes the light exit surface. Here, the distance h between the CCFL light source and the light incident surface of the diffusion plate was 4.5 mm. The luminance in the light source unit of Example 2-2 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 5 below.
　（比較例２－１）
　図２６（ａ）に示すように、光源上方に、ＤＰ、表面に干渉露光によるスペックルパターンを用いて形成された凹凸構造を有する拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、（比較例２－１）の光源ユニットを構成した。比較例２－１で用いた前記拡散シートは、拡散角度が前記シート面内の全領域において７１°である。なお、前記拡散シートは、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源と前記拡散シートの入光面との距離ｈを４．５ｍｍとした。比較例２－１の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表５に示す。 (Comparative Example 2-1)
As shown in FIG. 26 (a), DP, a diffusion sheet having a concavo-convex structure formed using a speckle pattern by interference exposure on the surface, DS, a prism sheet, and DBEF are arranged in this order above the light source. Thus, the light source unit of (Comparative Example 2-1) was configured. The diffusion sheet used in Comparative Example 2-1 has a diffusion angle of 71 ° in the entire region within the sheet surface. In addition, the said diffusion sheet was arrange | positioned so that an uneven surface may become a light emission surface. Here, the distance h between the CCFL light source and the light incident surface of the diffusion sheet was 4.5 mm. The luminance in the light source unit of Comparative Example 2-1 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 5 below.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　表５より、図２５（ｃ）に示すＤＰ／拡散シート／プリズムシート／ＤＢＥＦの構成、或いは、図２６（ａ）に示す拡散板／拡散シート／ＤＳ／プリズムシート／ＤＢＥＦの構成を持つ光源ユニットにおいて、本発明の拡散シートは、前記拡散角度差が４０°以上８０°以下の範囲内にない場合（比較例２－１）と比べ、輝度むらを軽減することができた。さらに、比較例２－１の構成において、ＣＣＦＬ光源の径の中心からＤＰの入光面までとの距離ｈを変化させていくと、ｈ＝１２．５のところで、実施例２－１、２－２と同等の輝度むらとなった。実施例２－１、２－２では、ｈ＝４．５であることを考慮すると、比較例２－１に比べて、ＣＣＦＬ光源の径の中心からＤＰの入光面までとの距離ｈを８ｍｍ短縮することができ（図２７（ａ））、光源ユニットを薄型化できることがわかる。 From Table 5, a light source unit having a DP / diffusion sheet / prism sheet / DBEF configuration shown in FIG. 25C or a diffusion plate / diffusion sheet / DS / prism sheet / DBEF configuration shown in FIG. In the diffusion sheet of the present invention, the uneven brightness was reduced compared to the case where the diffusion angle difference was not in the range of 40 ° to 80 ° (Comparative Example 2-1). Further, in the configuration of Comparative Example 2-1, when the distance h from the center of the diameter of the CCFL light source to the DP incident surface is changed, Examples 2-1 and 2 are obtained at h = 12.5. The brightness unevenness was equivalent to -2. In Examples 2-1 and 2-2, considering that h = 4.5, the distance h from the center of the diameter of the CCFL light source to the light incident surface of the DP is larger than that in Comparative Example 2-1. 8 mm can be shortened (FIG. 27A), and it can be seen that the light source unit can be thinned.
　実施例２－３、比較例２－２については、図２６（ｂ）に示すような基本構成を採る光源ユニットにおいて評価を行った。 Example 2-3 and Comparative Example 2-2 were evaluated in a light source unit having a basic configuration as shown in FIG.
　（実施例２－３）
　図２６（ｂ）に示すように、光源上方に本発明の拡散シート、ＤＰ、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例２－３の光源ユニットを構成した。本発明の拡散シートは、拡散角度の最大値が７０°、最小値が１°で、拡散角度差が６９°であり、図１０（ｂ）に示すように、前記拡散シート面内で拡散角度が分布している拡散シートを、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源と前記拡散シートの入光面との距離ｈを９．１ｍｍとした。実施例２－３の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表６に示す。 (Example 2-3)
As shown in FIG. 26 (b), the diffusion sheet, DP, DS, prism sheet, and DBEF of the present invention were arranged in this order above the light source to constitute a light source unit of Example 2-3. The diffusion sheet of the present invention has a maximum diffusion angle of 70 °, a minimum value of 1 °, and a diffusion angle difference of 69 °. As shown in FIG. 10B, the diffusion angle is within the plane of the diffusion sheet. The diffusion sheet in which is distributed is disposed so that the uneven surface becomes the light exit surface. Here, the distance h between the CCFL light source and the light incident surface of the diffusion sheet was set to 9.1 mm. The luminance in the light source unit of Example 2-3 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 6 below.
　（比較例２－２）
　図２６（ｂ）に示すように、光源上方に、表面に干渉露光によるスペックルパターンを用いて形成された凹凸構造を有する拡散シート、ＤＰ、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、比較例２－２の光源ユニットを構成した。比較例２－２で用いた前記拡散シートは、拡散角度が全領域において７１°である。なお、前記拡散シートは、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源と前記拡散シートの入光面との距離ｈを９．１ｍｍとした。比較例２－２の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表６に示す。 (Comparative Example 2-2)
As shown in FIG. 26 (b), a diffusion sheet having a concavo-convex structure formed on the surface using a speckle pattern by interference exposure, DP, DS, prism sheet, and DBEF are arranged in this order above the light source. Thus, the light source unit of Comparative Example 2-2 was configured. The diffusion sheet used in Comparative Example 2-2 has a diffusion angle of 71 ° in the entire region. In addition, the said diffusion sheet was arrange | positioned so that an uneven surface may become a light emission surface. Here, the distance h between the CCFL light source and the light incident surface of the diffusion sheet was set to 9.1 mm. The luminance in the light source unit of Comparative Example 2-2 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 6 below.
Figure JPOXMLDOC01-appb-T000006
Figure JPOXMLDOC01-appb-T000006
　表６より、図２６（ｂ）に示す、拡散シート／ＤＰ／ＤＳ／ＢＥＦ／ＤＢＥＦの構成を持つ光源ユニットにおいて、本発明の拡散シートは、前記拡散角度差が４０°以上８０°以下の範囲内にない場合（比較例２－２）と比べ、輝度むらを軽減することができた。さらに、比較例２－２の構成において、ＣＣＦＬ光源の径の中心から前記拡散シート入光面までとの距離ｈを変化させていくと、ｈ＝１２．５のところで、実施例２－３と同等の輝度むらとなった。実施例２－３では、ｈ＝９．５であることを考慮すると、比較例２－２に比べて、ＣＣＦＬ光源の径の中心から前記拡散シートの入光面までとの距離ｈを３ｍｍ短縮することができ（図２７（ａ））、光源ユニットを薄型化できることがわかる。 From Table 6, in the light source unit having the structure of diffusion sheet / DP / DS / BEF / DBEF shown in FIG. 26 (b), the diffusion sheet of the present invention has a diffusion angle difference in the range of 40 ° to 80 °. As compared with the case of not within (Comparative Example 2-2), the luminance unevenness could be reduced. Further, in the configuration of Comparative Example 2-2, when the distance h from the center of the diameter of the CCFL light source to the diffusion sheet light incident surface is changed, when h = 12.5, Example 2-3 The brightness unevenness was equivalent. In Example 2-3, considering that h = 9.5, the distance h from the center of the diameter of the CCFL light source to the light incident surface of the diffusion sheet is shortened by 3 mm compared to Comparative Example 2-2. As shown in FIG. 27A, it can be seen that the light source unit can be thinned.
　実施例２－４については、光源ユニットの光源として、直径３．４ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．８ｍｍとし、前記光源同士の間隔ｐが４７．６ｍｍとなるように８本配置して輝度評価用の光源ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光源ユニットから７５ｃｍ離して設置し、光源ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±２３．８ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。
　ここで、輝度むらの判定基準を下記のように３段階（◎、○、×）に分類した。
◎：Ｓ．Ｄ．　≦０．００２
○：０．００２＜Ｓ．Ｄ．　≦０．００４
×：０．００４＜Ｓ．Ｄ． For Example 2-4, a CCFL light source having a diameter of 3.4 mmφ and a length of 710 mm was used as the light source of the light source unit. The CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and eight are arranged so that the distance p between the light sources is 47.6 mm. A light source unit was prepared. The brightness and brightness unevenness were measured by using a two-dimensional color luminance meter (CA2000) manufactured by Konica Minolta, installed 75 cm away from the light source unit, and the average brightness value measured in the range of 20 mm × 190 mm in the center of the light source unit as brightness. did. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and in the y-axis direction, the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 23.8 mm from each point. Luminance unevenness was obtained.
Here, the judgment criteria for luminance unevenness were classified into the following three levels (◎, ○, ×).
A: S. D. ≦ 0.002
A: 0.002 <S. D. ≦ 0.004
X: 0.004 <S. D.
　実施例２－４については、図２６（ａ）に示すような基本構成を採る光源ユニットにおいて評価を行った。 Example 2-4 was evaluated in a light source unit having a basic configuration as shown in FIG.
　（実施例２－４）
　図２６（ａ）に示すように、光源上方にＤＰ、本発明の拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例２－４の光源ユニットを構成した。本発明の拡散シートは、拡散角度の最大値が５０°、拡散角度の最小値が１°で、拡散角度差が４９°であり、図１０（ｃ）に示すように、前記拡散シート面内で拡散角度が分布している拡散シートを、凹凸面が出光面となるように用いた。ここで、ＣＣＦＬ光源とＤＰの入光面との距離ｈを１４．５ｍｍとした。実施例２－４の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表７に示す。 (Example 2-4)
As shown in FIG. 26 (a), the light source unit of Example 2-4 was configured by arranging DP, the diffusion sheet of the present invention, DS, the prism sheet, and DBEF in this order above the light source. The diffusion sheet of the present invention has a maximum diffusion angle value of 50 °, a minimum diffusion angle value of 1 °, and a diffusion angle difference of 49 °. As shown in FIG. The diffusion sheet in which the diffusion angle is distributed was used so that the uneven surface becomes the light exit surface. Here, the distance h between the CCFL light source and the light incident surface of the DP was 14.5 mm. The luminance in the light source unit of Example 2-4 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 7 below.
　（比較例２－３）
　図２６（ａ）に示すように、光源上方にＤＰ、表面に非平面スペックルによって特徴付けられた凹凸構造を有し、全領域に渡って拡散角度が４１°であるような拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、比較例２－３の光源ユニットを構成した。なお、前記拡散シートは、凹凸面が出光面となるように用いた。ここで、ＣＣＦＬ光源とＤＰの入光面との距離ｈを１４．５ｍｍとした。比較例２－３の光源ユニットにおける輝度、輝度むらを上記の方法で測定した。その結果を下記表７に併記する。 (Comparative Example 2-3)
As shown in FIG. 26 (a), a diffusion sheet having a concavo-convex structure characterized by DP above the light source and non-planar speckles on the surface and having a diffusion angle of 41 ° over the entire region, DS , Prism sheet, and DBEF were arranged in this order to constitute a light source unit of Comparative Example 2-3. In addition, the said diffusion sheet was used so that an uneven surface might become a light emission surface. Here, the distance h between the CCFL light source and the light incident surface of the DP was 14.5 mm. The luminance and luminance unevenness in the light source unit of Comparative Example 2-3 were measured by the above method. The results are also shown in Table 7 below.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　表７より、図２６（ａ）に示すＤＰ／拡散シート／ＤＳ／プリズムシート／ＤＢＥＦの構成を持つ光源ユニットにおいて、本発明の拡散シートは、前記拡散角度差が４０°以上８０°以下範囲内にない場合（比較例２－３）と比べ、輝度むらを小さくすることができた。さらに、比較例２－３の構成において、ＣＣＦＬ光源の径の中心間距離ｐを変化させていくと、ｐ＝２３．７のところで、実施例２－４と同等の輝度むらとなった。実施例２－４では、ｐ＝４７．６であることを考慮すると、比較例２－３に比べて、ＣＣＦＬ光源の径の中心間距離ｐを約２倍に拡大することができ（図２７（ｂ））、結果としてＣＣＦＬ光源の数を削減できることがわかる。 From Table 7, in the light source unit having the configuration of DP / diffusion sheet / DS / prism sheet / DBEF shown in FIG. 26 (a), the diffusion sheet of the present invention has a diffusion angle difference in the range of 40 ° to 80 °. In comparison with the case (Comparative Example 2-3), the luminance unevenness could be reduced. Further, in the configuration of Comparative Example 2-3, when the center-to-center distance p of the CCFL light source diameter was changed, luminance unevenness equivalent to that of Example 2-4 was obtained at p = 23.7. In Example 2-4, considering that p = 47.6, the center-to-center distance p of the diameter of the CCFL light source can be increased approximately twice as compared with Comparative Example 2-3 (FIG. 27). (B)) As a result, it can be seen that the number of CCFL light sources can be reduced.
　実施例２－５及び実施例２－６、比較例２－４及び比較例２－５において、光学シートとして特に記載がないものについて、すなわち、反射シート、拡散板、レンズシート、プリズムシート、反射型偏光シートについては、それぞれ、ポリエステル樹脂からなる白色反射シート（以下、ＲＳと略記）、ポリスチレンからなり、粒径２μｍ、真比重１．３５のシリコーン微粒子を拡散剤として２００００ｐｐｍ含有する、厚さ２．０ｍｍの拡散板（以下、ＤＰと略記）、厚さ２５０μｍのＰＥＴ基材上に樹脂ビーズとバインダーが塗工された拡散シート（以下、ＤＳと略記）、厚さ２５０μｍのＰＥＴ基材上に頂角９０°、ピッチ５０μｍのプリズム条列がＵＶ硬化性樹脂によって賦形されたプリズムシート（以下、プリズムシートと略記）、反射型偏光シート（以下、ＤＢＥＦと略記。３Ｍ社製）を用いた。 In Example 2-5, Example 2-6, Comparative Example 2-4, and Comparative Example 2-5, what is not particularly described as an optical sheet, that is, a reflection sheet, a diffusion plate, a lens sheet, a prism sheet, a reflection Each of the polarizing plates is a white reflective sheet (hereinafter abbreviated as RS) made of a polyester resin, polystyrene, and contains 20000 ppm of silicone fine particles having a particle size of 2 μm and a true specific gravity of 1.35 as a diffusing agent. 0.0 mm diffusion plate (hereinafter abbreviated as DP), diffusion sheet (hereinafter abbreviated as DS) coated with resin beads and binder on a 250 μm thick PET base material, on a 250 μm thick PET base material Prism sheet (hereinafter abbreviated as “prism sheet”) in which prism rows with an apex angle of 90 ° and a pitch of 50 μm are shaped by a UV curable resin, A reflective polarizing sheet (hereinafter abbreviated as DBEF; manufactured by 3M) was used.
　また、実施例２－５及び実施例２－６、比較例２－４及び比較例２－５については、光源ユニットの光源として、ＣＲＥＥ社製の３．５ｍｍ角、高さ２．０ｍｍの白色ＬＥＤ光源を用いた。前記光源の中心間距離をｘ軸方向、ｙ軸方向に２４．０ｍｍとして１０列ずつ、格子状に並べて配置し、光源ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光源ユニットから７０ｃｍ離して設置し、光源ユニットの中心部１２０ｍｍ×１２０ｍｍの範囲で測定した平均輝度値を輝度とした。 Further, in Examples 2-5, 2-6, Comparative Examples 2-4, and Comparative Example 2-5, a white light of 3.5 mm square and 2.0 mm height made by CREE was used as the light source of the light source unit. An LED light source was used. The distance between the centers of the light sources was set to 24.0 mm in the x-axis direction and the y-axis direction, and 10 rows were arranged in a grid and arranged to form a light source unit. The brightness and brightness unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000), placed 70 cm away from the light source unit, and an average brightness value measured in the range of 120 mm × 120 mm in the center of the light source unit as brightness. did.
　輝度むらは、ｘ軸方向及びｙ軸方向の２方向について算出した値の平均値とした。まず、ｘ軸（１２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±１２ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。同様に、ｙ軸（１００ｍｍ）方向の平均輝度値を求め、ｘ軸方向について、各々の点の輝度値を各々の点から±１２ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。最後に、ｘ軸方向の標準偏差とｙ軸方向の標準偏差を平均した値を、光源ユニットの輝度むらとした。なお、ＬＥＤ光源は点光源であるので、図６のように、ｘ軸及びｙ軸上において、それぞれ拡散角度の分布を考えた。
　ここで、輝度むらの判定基準を下記のように３段階（◎、○、×）に分類した。
◎：Ｓ．Ｄ．　≦０．００２
○：０．００２＜Ｓ．Ｄ．　≦０．００４
×：０．００４＜Ｓ．Ｄ． The luminance unevenness was an average value of values calculated in two directions of the x-axis direction and the y-axis direction. First, an average luminance value in the x-axis (120 mm) direction is obtained, and luminance unevenness is obtained as a standard deviation of values obtained by dividing the luminance value of each point by the average luminance value of ± 12 mm from each point in the y-axis direction. Asked. Similarly, the average luminance value in the y-axis (100 mm) direction is obtained, and the luminance unevenness is obtained as a standard deviation of values obtained by dividing the luminance value of each point by the average luminance value of ± 12 mm from each point in the x-axis direction. Asked. Finally, a value obtained by averaging the standard deviation in the x-axis direction and the standard deviation in the y-axis direction was used as the luminance unevenness of the light source unit. Since the LED light source is a point light source, the distribution of diffusion angles on the x-axis and the y-axis was considered as shown in FIG.
Here, the judgment criteria for luminance unevenness were classified into the following three levels (◎, ○, ×).
A: S. D. ≦ 0.002
A: 0.002 <S. D. ≦ 0.004
X: 0.004 <S. D.
　（実施例２－５）
　図２４に示すように、光源上方にＤＰ、本発明の拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例２－５の光源ユニットを構成した。本発明の拡散シートは、拡散角度の最大値が７０°、拡散角度の最小値が１０°で、拡散角度差が６０°であり、図１０（ｂ）に示すように、拡散角度が変化している拡散シートを、凹凸面が出光面となるように用いた。ここで、ＲＳとＤＰの入光面との距離ｈを１６．０ｍｍとした。実施例２－５の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表８に示す。 (Example 2-5)
As shown in FIG. 24, the DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute a light source unit of Example 2-5. In the diffusion sheet of the present invention, the maximum value of the diffusion angle is 70 °, the minimum value of the diffusion angle is 10 °, and the diffusion angle difference is 60 °. As shown in FIG. 10B, the diffusion angle changes. The diffusion sheet used was used so that the uneven surface became the light exit surface. Here, the distance h between the light incident surface of RS and DP was set to 16.0 mm. The luminance in the light source unit of Example 2-5 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 8 below.
　（実施例２－６）
　図２４に示すように、光源上方にＤＰ、本発明の拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、実施例２－６の光源ユニットを構成した。本発明の拡散シートは、拡散角度の最大値が５０°、拡散角度の最小値が５°で、拡散角度差が４５°であり、図１０（ｂ）に示すように、拡散角度が変化している拡散シートを、凹凸面が入光面となるように用いた。ここで、ＲＳとＤＰの入光面との距離ｈを１６．０ｍｍとした。実施例２－６の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表８に併記する。 (Example 2-6)
As shown in FIG. 24, the DP, the diffusion sheet of the present invention, the DS, the prism sheet, and the DBEF are arranged in this order above the light source to constitute a light source unit of Example 2-6. In the diffusion sheet of the present invention, the maximum value of the diffusion angle is 50 °, the minimum value of the diffusion angle is 5 °, and the difference in diffusion angle is 45 °. As shown in FIG. The diffusion sheet used was used so that the uneven surface becomes the light incident surface. Here, the distance h between the light incident surface of RS and DP was set to 16.0 mm. The luminance in the light source unit of Example 2-6 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 8 below.
　（比較例２－４）
　図２４に示すように、光源上方にＤＰ、表面に干渉露光によるスペックルパターンを用いて形成された凹凸構造を有し、全領域に渡って拡散角度が７０°であるような拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、比較例２－４の光源ユニットを構成した。なお、前記拡散シートは、凹凸面が出光面となるように用いた。ここで、ＲＳとＤＰの入光面との距離ｈを１６．０ｍｍとした。比較例２－４の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表８に併記する。 (Comparative Example 2-4)
As shown in FIG. 24, a diffusion sheet having a concavo-convex structure formed using DP above the light source and a speckle pattern formed by interference exposure on the surface, and having a diffusion angle of 70 ° over the entire region, DS , Prism sheet, and DBEF were arranged in this order to constitute a light source unit of Comparative Example 2-4. In addition, the said diffusion sheet was used so that an uneven surface might become a light emission surface. Here, the distance h between the light incident surface of RS and DP was set to 16.0 mm. The luminance in the light source unit of Comparative Example 2-4 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 8 below.
　（比較例２－５）
　図２４に示すように、光源上方にＤＰ、表面に干渉露光によるスペックルパターンを用いて形成された凹凸構造を有し、全領域に渡って拡散角度が５０°であるような拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、比較例２－５の光源ユニットを構成した。なお、前記拡散シートは、凹凸面が入光面となるように用いた。ここで、ＲＳとＤＰの入光面との距離ｈを１６．０ｍｍとした。比較例２－５の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表８に併記する。 (Comparative Example 2-5)
As shown in FIG. 24, a diffusion sheet having a concavo-convex structure formed using DP above the light source and a speckle pattern formed by interference exposure on the surface, and having a diffusion angle of 50 ° over the entire region, DS , Prism sheet, and DBEF were arranged in this order to constitute a light source unit of Comparative Example 2-5. In addition, the said diffusion sheet was used so that an uneven surface may become a light-incidence surface. Here, the distance h between the light incident surface of RS and DP was set to 16.0 mm. The luminance in the light source unit of Comparative Example 2-5 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 8 below.
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　表８より、図２４に示すＤＰ／拡散シート／ＤＳ／プリズムシート／ＤＢＥＦの構成を持つ光源ユニットにおいて、本発明の拡散シートは、拡散角度が全領域に渡って均一な拡散シート（比較例２－４，２－５）を用いた構成と比較して、輝度むらを小さくすることができた。さらに、比較例２－４、２－５の構成において、ＲＳとＤＰとの距離ｈを変化させていくと、ｈ＝３２．０のところで、実施例２－５，２－６と同等の輝度むらとなった。実施例２－５，２－６では、ｈ＝１６．０であることを考慮すると、比較例２－４，２－５に比べて、ＲＳからＤＰの入光面までの距離ｈを１６ｍｍ、約半分に短縮することができ、光源ユニットを薄型化できることがわかる。 From Table 8, in the light source unit having the configuration of DP / diffusion sheet / DS / prism sheet / DBEF shown in FIG. 24, the diffusion sheet of the present invention has a diffusion sheet having a uniform diffusion angle over the entire region (Comparative Example 2). As compared with the configuration using −4, 2-5), the luminance unevenness could be reduced. Further, in the configurations of Comparative Examples 2-4 and 2-5, when the distance h between RS and DP is changed, the luminance equivalent to that of Examples 2-5 and 2-6 is obtained at h = 32.0. It became uneven. In Examples 2-5 and 2-6, considering that h = 16.0, compared with Comparative Examples 2-4 and 2-5, the distance h from the light incident surface of the DP to the DP is 16 mm, It can be shortened to about half, and it can be seen that the light source unit can be made thinner.
　実施例３は、上記実施の形態２で示した内容に対応している。なお、実施例３に示される拡散角度は、拡散シート凹凸面を入射面とし、前記凹凸面の法線方向に入射した光に対する透過光強度の角度分布を、変角光度計で測定した結果から算出している。例えば、５°は、等方性の拡散シートであり、シート面内のどの方向の拡散角度も５°であることを表す。また一方、１０°×５°は異方性の拡散シートであり、シート面内の直交する２方向における拡散角度が、１０°と５°であることを表す。 Example 3 corresponds to the contents shown in the second embodiment. The diffusion angle shown in Example 3 is based on the result of measuring the angle distribution of the transmitted light intensity with respect to the light incident in the normal direction of the concavo-convex surface with the diffusing sheet concavo-convex surface as an incident surface, using a goniophotometer. Calculated. For example, 5 ° is an isotropic diffusion sheet, and the diffusion angle in any direction within the sheet surface is 5 °. On the other hand, 10 ° × 5 ° is an anisotropic diffusion sheet, and the diffusion angles in two orthogonal directions within the sheet surface are 10 ° and 5 °.
　実施例及び比較例に記載した、シート面内において拡散角度分布を有するような拡散シートは、前記シート面内の一方向で拡散角度が周期的に変化し、さらに、前記拡散シートを含む光源ユニットにおいて、ＣＣＦＬ光源の長手方向と直交する方向と、前記拡散角度が周期的に変化する方向を一致させている。また、光源からの照度分布に対応するように前記拡散シート面内における拡散角度分布を設計し、照度が高い領域には前記拡散シートの拡散角度が高い領域を配置して用いた。 The diffusion sheet having a diffusion angle distribution in the sheet surface described in the examples and comparative examples, the diffusion angle periodically changes in one direction in the sheet surface, and further includes a light source unit including the diffusion sheet , The direction orthogonal to the longitudinal direction of the CCFL light source is matched with the direction in which the diffusion angle periodically changes. Moreover, the diffusion angle distribution in the surface of the diffusion sheet was designed so as to correspond to the illuminance distribution from the light source, and a region where the diffusion angle of the diffusion sheet was high was arranged and used in a region where the illuminance was high.
　実施例３－１及び実施例３－２、比較例３－１から比較例３－３については、本発明の光線制御ユニットに係る光学シートとして、厚さ１．５ｍｍのポリスチレン製で、内部に真比重１．３５、平均粒径２μｍのシリコーン微粒子を３０００ｐｐｍ含有し、出光面に高さ１３０μｍ、ピッチ３２０μｍのレンチキュラーレンズが形成されたもの（旭化成イーマテリアルズ（株）製）を、前記レンズの長手方向を、ＣＣＦＬ光源の長手方向と平行に配置した光源ユニットにおいて評価を行った。なお、前記レンチキュラーレンズが形成された面を、出光面とした。 Example 3-1 and Example 3-2, and Comparative Example 3-1 to Comparative Example 3-3 are made of polystyrene having a thickness of 1.5 mm as an optical sheet according to the light control unit of the present invention. A lens containing 3000 ppm of silicone fine particles with a true specific gravity of 1.35 and an average particle diameter of 2 μm and having a lenticular lens with a height of 130 μm and a pitch of 320 μm formed on the light exit surface (manufactured by Asahi Kasei E-Materials Co., Ltd.) Evaluation was performed in a light source unit in which the longitudinal direction was arranged in parallel with the longitudinal direction of the CCFL light source. The surface on which the lenticular lens was formed was defined as a light exit surface.
　実施例３－１及び実施例３－２、比較例３－１から比較例３－３において、光学シートとして実施例において記載がないものについて、すなわち、反射シート、レンズシート、プリズムシート、反射型偏光シートについては、ソニー社製のＢＲＡＶＩＡ　ＫＤＬ３２－Ｆ１に使用されている反射シート（以下、ＲＳと略記）、レンズシート（以下、ＤＳと略記）、プリズムシート（ＢＥＦＩＩＩ（３Ｍ（株）製））、反射型偏光シート（ＤＢＥＦ（３Ｍ（株）製））を用いた。 In Examples 3-1 and 3-2, and Comparative Examples 3-1 to 3-3, optical sheets that are not described in the examples, that is, a reflective sheet, a lens sheet, a prism sheet, and a reflective type Regarding the polarizing sheet, a reflective sheet (hereinafter abbreviated as RS), a lens sheet (hereinafter abbreviated as DS), a prism sheet (BEFIII (manufactured by 3M Corporation)) used in BRAVIA KDL32-F1 manufactured by Sony Corporation A reflective polarizing sheet (DBEF (manufactured by 3M Co., Ltd.)) was used.
　実施例３－１及び実施例３－２、比較例３－１から比較例３－３については、光源ユニットの光源として、直径３．０ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．８ｍｍとし、前記光源同士の間隔ｐが２３．７ｍｍとなるように１６本配置して輝度評価用の光源ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光源ユニットから７５ｃｍ離して設置し、光源ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±１１．８ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。 For Example 3-1, Example 3-2, and Comparative Examples 3-1 to 3-3, a CCFL light source having a diameter of 3.0 mmφ and a length of 710 mm was used as the light source of the light source unit. The CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.8 mm, and 16 are arranged so that the distance p between the light sources is 23.7 mm. A light source unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000) at a distance of 75 cm from the light source unit, and the average luminance value measured in the range of 20 mm × 190 mm in the center of the light source unit as luminance. did. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 11.8 mm from each point in the y-axis direction. Luminance unevenness was obtained.
　ここで、前記光源ユニットにおいて、目視による輝度むらが許容できるような標準偏差の最大値０．００４を境界とし、輝度むらの判定基準を下記のように２段階（○、×）に分類した。
○：Ｓ．Ｄ．　≦０．００４
×：０．００４＜Ｓ．Ｄ． Here, in the light source unit, the standard deviation maximum value 0.004 that allows permissible brightness unevenness was used as a boundary, and the determination standard of brightness unevenness was classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.004
X: 0.004 <S. D.
　（実施例３－１）
　図２５（ｃ）に示すように、光源から上方に、本発明の光線制御ユニットとして、表面にレンチキュラーレンズが形成された光学シート、本発明の拡散シートの順で配置し、さらにその上方に、プリズムシート（ＢＥＦIII）、反射型偏光シート（ＤＢＥＦ）と、をこの順で配置し、実施例３－１の光源ユニットを構成した。ここで、本発明の拡散シートは、拡散角度の最大値が７０°、最小値が５０°で、図１０（ｆ）に示すように、前記拡散シート面内で滑らかに拡散角度が分布しているような拡散シートを、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源の径の中心と前記レンチキュラーレンズが形成された光学シートの入光面との距離ｈを４．６ｍｍとした。実施例３－１の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表９に示す。 Example 3-1
As shown in FIG. 25 (c), an optical sheet having a lenticular lens formed on the surface thereof and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source. The prism sheet (BEFIII) and the reflective polarizing sheet (DBEF) were arranged in this order to constitute the light source unit of Example 3-1. Here, in the diffusion sheet of the present invention, the maximum value of the diffusion angle is 70 ° and the minimum value is 50 °, and the diffusion angle is smoothly distributed in the surface of the diffusion sheet as shown in FIG. The diffusion sheet as described above was disposed so that the uneven surface becomes the light exit surface. Here, the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the lenticular lens is formed was 4.6 mm. The luminance in the light source unit of Example 3-1 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 9 below.
　（実施例３－２）
　図２６（ａ）に示すように、光源から上方に、本発明の光線制御ユニットとして、表面にレンチキュラーレンズが形成された光学シート、本発明の拡散シートの順で配置し、さらにその上方に、ＤＳ、プリズムシート（ＢＥＦIII）、反射型偏光シート（ＤＢＥＦ）と、をこの順で配置し、実施例３－２の光源ユニットを構成した。ここで、本発明の拡散シートは、拡散角度の最大値が３０°、拡散角度の最小値が０．１°で、図１０（ｆ）に示すように、前記拡散シート面内で滑らかに拡散角度が分布しているような拡散シートを、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源の径の中心と前記レンチキュラーレンズが形成された光学シートの入光面との距離ｈを４．６ｍｍとした。実施例３－２の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表９に併記する。 (Example 3-2)
As shown in FIG. 26 (a), an optical sheet having a lenticular lens formed on the surface thereof and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source. DS, a prism sheet (BEFIII), and a reflective polarizing sheet (DBEF) were arranged in this order to constitute a light source unit of Example 3-2. Here, the diffusion sheet of the present invention has a maximum diffusion angle of 30 ° and a minimum diffusion angle of 0.1 °, and smoothly diffuses in the plane of the diffusion sheet as shown in FIG. 10 (f). A diffusion sheet in which the angles are distributed was arranged so that the concavo-convex surface was the light exit surface. Here, the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the lenticular lens is formed was 4.6 mm. The luminance in the light source unit of Example 3-2 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 9 below.
　（比較例３－１）
　光源の下方にＲＳを配置し、光源から上方に、表面にレンチキュラーレンズが形成された光学シート、ＤＳ、プリズムシート（ＢＥＦIII）、反射型偏光シート（ＤＢＥＦ）と、をこの順で配置し、比較例３－１の光源ユニットを構成した。なお、前記レンチキュラーレンズが形成された光学シートは、レンズ形成面が出光面となるように配置した。ここで、ＣＣＦＬ光源の径の中心と前記レンチキュラーレンズが形成された光学シートの入光面との距離ｈを４．６ｍｍとした。比較例３－１の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表９に併記する。 (Comparative Example 3-1)
An RS is placed below the light source, and an optical sheet with a lenticular lens formed on the surface, DS, prism sheet (BEFIII), and reflective polarizing sheet (DBEF) are placed in this order from the light source and compared. The light source unit of Example 3-1 was configured. The optical sheet on which the lenticular lens was formed was disposed so that the lens forming surface was the light exit surface. Here, the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the lenticular lens is formed was 4.6 mm. The luminance in the light source unit of Comparative Example 3-1 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 9 below.
　（比較例３－２）
　光源の下方にＲＳを配置し、光源から上方に、表面にレンチキュラーレンズが形成された光学シート、表面に干渉露光によるスペックルパターンを用いて形成された凹凸構造を有する拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、比較例３－２の光源ユニットを構成した。比較例３－２で用いた前記拡散シートは、拡散角度が前記シート面内の全領域において７０°である。なお、前記凹凸構造を有する拡散シートは、凹凸面が出光面となるように配置し、ここで、ＣＣＦＬ光源の径の中心と前記レンチキュラーレンズが形成された光学シートの入光面との距離ｈを４．６ｍｍとした。比較例３－２の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表９に併記する。 (Comparative Example 3-2)
An optical sheet in which an RS is arranged below the light source and a lenticular lens is formed on the surface above the light source, a diffusion sheet having a concavo-convex structure formed on the surface using a speckle pattern by interference exposure, DS, and prism sheet , DBEF are arranged in this order to constitute a light source unit of Comparative Example 3-2. The diffusion sheet used in Comparative Example 3-2 has a diffusion angle of 70 ° in the entire region within the sheet surface. The diffusion sheet having the concavo-convex structure is arranged such that the concavo-convex surface becomes a light exit surface, where the distance h between the center of the diameter of the CCFL light source and the light entrance surface of the optical sheet on which the lenticular lens is formed. Was 4.6 mm. The luminance in the light source unit of Comparative Example 3-2 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 9 below.
　（比較例３－３）
　光源の下方にＲＳを配置し、光源から上方に、表面にレンチキュラーレンズが形成された光学シート、表面に干渉露光によるスペックルパターンを用いて形成された凹凸構造を有する拡散シート、ＤＳ、プリズムシート、ＤＢＥＦと、をこの順で配置し、比較例３－３の光源ユニットを構成した。比較例３－３で用いた前記拡散シートは、拡散角度が前記シート面内の全領域において３０°である。なお、前記凹凸構造を有する拡散シートは、凹凸面が出光面となるように配置し、ここで、ＣＣＦＬ光源の径の中心と前記レンチキュラーレンズが形成された光学シートの入光面との距離ｈを４．６ｍｍとした。比較例３－３の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表９に併記する。 (Comparative Example 3-3)
An optical sheet in which an RS is arranged below the light source and a lenticular lens is formed on the surface above the light source, a diffusion sheet having a concavo-convex structure formed on the surface using a speckle pattern by interference exposure, DS, and prism sheet , DBEF are arranged in this order to constitute a light source unit of Comparative Example 3-3. The diffusion sheet used in Comparative Example 3-3 has a diffusion angle of 30 ° in the entire region within the sheet surface. The diffusion sheet having the concavo-convex structure is arranged such that the concavo-convex surface becomes a light exit surface, where the distance h between the center of the diameter of the CCFL light source and the light entrance surface of the optical sheet on which the lenticular lens is formed. Was 4.6 mm. The luminance in the light source unit of Comparative Example 3-3 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 9 below.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　表９より、図２５（ｃ）に示す本発明の光線制御ユニット／プリズムシート／ＤＢＥＦの構成、或いは、図２６（ａ）に示す本発明の光線制御ユニット／ＤＳ／プリズムシート／ＤＢＥＦの構成を持つ光源ユニットにおいて、本発明の光線制御ユニットは、シート面内で前記拡散角度が周期的に変化する拡散シートを用いない場合（比較例３－１，３－２，３－３）と比較して、輝度むらを軽減することができた。 From Table 9, the configuration of the light beam control unit / prism sheet / DBEF of the present invention shown in FIG. 25C or the configuration of the light beam control unit / DS / prism sheet / DBEF of the present invention shown in FIG. In the light source unit having the light source unit, the light beam control unit of the present invention is compared with the case where the diffusion sheet in which the diffusion angle periodically changes in the sheet surface is not used (Comparative Examples 3-1, 3-2, and 3-3). Brightness unevenness.
　さらに、比較例３－１の構成において、ＣＣＦＬ光源の径の中心から前記レンチキュラーレンズが形成された光学シートの入光面までとの距離ｈを変化させていくと、ｈ＝１０．６のところで、実施例３－１，３－２と同等の輝度むらとなった。実施例３－１，３－２では、ｈ＝４．６であることを考慮すると、比較例３－１に比べて、ＣＣＦＬ光源の径の中心から前記レンチキュラーレンズが形成された光学シートの入光面までとの距離ｈを６ｍｍ短縮することができ（図２７（ａ））、光源ユニットを薄型化できることがわかる。 Further, in the configuration of Comparative Example 3-1, when the distance h from the center of the CCFL light source diameter to the light incident surface of the optical sheet on which the lenticular lens is formed is changed, h = 10.6. The brightness unevenness was the same as in Examples 3-1 and 3-2. In Examples 3-1 and 3-2, considering that h = 4.6, the optical sheet on which the lenticular lens is formed is inserted from the center of the diameter of the CCFL light source as compared with Comparative Example 3-1. It can be seen that the distance h to the light surface can be shortened by 6 mm (FIG. 27A), and the light source unit can be made thinner.
　実施例３－３、実施例３－４、及び比較例３－５については、本発明の光線制御ユニットに係る光学シートとして、厚さ１．５ｍｍのポリスチレン製で、内部に拡散剤を含有せず、出光面に高さ１００μｍ、ピッチ３００μｍで、頂点の丸まったプリズム条列（Ｒプリズム）が形成されたもの（旭化成イーマテリアルズ（株）製）を、前記Ｒプリズムの長手方向を、ＣＣＦＬ光源の長手方向と平行に配置した光源ユニットにおいて評価を行った。なお、前記Ｒプリズムが形成された面を、出光面とした。 In Example 3-3, Example 3-4, and Comparative Example 3-5, the optical sheet according to the light control unit of the present invention is made of polystyrene having a thickness of 1.5 mm, and contains a diffusing agent inside. First, a prism array (R prism) with a height of 100 μm and a pitch of 300 μm formed on the light-emitting surface (manufactured by Asahi Kasei E-Materials Co., Ltd.) is used. Evaluation was performed in a light source unit arranged in parallel with the longitudinal direction of the light source. The surface on which the R prism was formed was defined as the light exit surface.
　実施例３－３、実施例３－４、及び比較例３－５において、光学シートとして実施例において記載がないものについて、すなわち、反射シート、レンズシート、プリズムシート、反射型偏光シートについては、ソニー社製のＢＲＡＶＩＡ　ＫＤＬ３２－ＪＥ１に使用されている反射シート（以下、ＲＳと略記）、レンズシート（以下、ＤＳと略記）、プリズムシート（ＢＥＦIII（３Ｍ（株）製））、反射型偏光シート（ＤＢＥＦ（３Ｍ（株）製））を用いた。 In Example 3-3, Example 3-4, and Comparative Example 3-5, what is not described in the examples as an optical sheet, that is, for a reflective sheet, a lens sheet, a prism sheet, and a reflective polarizing sheet, Reflective sheet (hereinafter abbreviated as RS), lens sheet (hereinafter abbreviated as DS), prism sheet (BEFIII (manufactured by 3M)), reflective polarizing sheet used in Sony BRAVIA KDL32-JE1 (DBEF (manufactured by 3M)) was used.
　実施例３－３、実施例３－４、及び比較例３－５については、光源ユニットの光源として、直径３．４ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．７ｍｍとし、前記光源同士の間隔ｐが４７．６ｍｍとなるように８本配置して輝度評価用の光源ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光源ユニットから７５ｃｍ離して設置し、光源ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±１１．８ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。 For Example 3-3, Example 3-4, and Comparative Example 3-5, a CCFL light source having a diameter of 3.4 mmφ and a length of 710 mm was used as the light source of the light source unit. For the luminance evaluation, the CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.7 mm, and the distance p between the light sources is 87.6 mm. A light source unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000) at a distance of 75 cm from the light source unit, and the average luminance value measured in the range of 20 mm × 190 mm in the center of the light source unit as luminance. did. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 11.8 mm from each point in the y-axis direction. Luminance unevenness was obtained.
　ここで、前記光源ユニットにおいて目視による輝度むらが許容できるような標準偏差の最大値０．００４を境界とし、輝度むらの判定基準を下記のように２段階（○、×）に分類した。
○：Ｓ．Ｄ．　≦０．００４
×：０．００４＜Ｓ．Ｄ． Here, with the standard deviation maximum value 0.004 that can allow visual luminance unevenness in the light source unit as a boundary, the determination standard of luminance unevenness was classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.004
X: 0.004 <S. D.
　（実施例３－３）
　図２６（ａ）に示すように、光源から上方に、本発明の光線制御ユニットとして、表面にプリズム条列が形成された光学シート、本発明の拡散シートの順で配置し、さらにその上方に、ＤＳ、プリズムシート（ＢＥＦIII）、反射型偏光シート（ＤＢＥＦ）と、をこの順で配置し、実施例３－３の光源ユニットを構成した。前記光学シートには、表面にピッチ３００μｍ、高さ１００μｍで先端部が丸まった形状のプリズム条列（Ｒプリズム）が形成されており、前記Ｒプリズム形成面を出光面として用いた。また、本発明の光線制御ユニットに係る拡散シートは、拡散角度の最大値が６０°、最小値が０．１°で、図１０（ｂ）に示すように、前記拡散シート面内で滑らかに拡散角度が分布しているような拡散シートを、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源の径の中心と前記Ｒプリズムが形成された光学シートの入光面との距離ｈを８．６ｍｍとした。実施例３－３の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表１０に示す。 Example 3-3
As shown in FIG. 26 (a), an optical sheet having a prism array formed on the surface and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source, and further above that. , DS, prism sheet (BEFIII), and reflective polarizing sheet (DBEF) were arranged in this order to constitute a light source unit of Example 3-3. The optical sheet has a prism array (R prism) having a surface with a pitch of 300 μm and a height of 100 μm and a rounded tip, and the R prism forming surface was used as a light exit surface. Further, the diffusion sheet according to the light beam control unit of the present invention has a maximum diffusion angle of 60 ° and a minimum value of 0.1 °, and is smooth in the diffusion sheet surface as shown in FIG. A diffusion sheet in which the diffusion angle is distributed was disposed so that the uneven surface becomes the light exit surface. Here, the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the R prism was formed was 8.6 mm. The luminance in the light source unit of Example 3-3 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 10 below.
　（実施例３－４）
　図２６（ａ）に示すように、光源から上方に、本発明の光線制御ユニットとして、表面にプリズム条列が形成された光学シート、本発明の拡散シートの順で配置し、さらにその上方に、プリズムシート（ＢＥＦIII）をプリズムの延在方向を直交させて２枚と、表面に干渉露光によるスペックルパターンを用いて形成された凹凸構造を有する拡散シートと、をこの順で配置し、実施例３－４の光源ユニットを構成した。前記光学シートには、表面にピッチ３００μｍ、高さ１００μｍで先端部が丸まった形状のプリズム条列（Ｒプリズム）が形成されており、前記Ｒプリズム形成面を出光面として用いた。なお、２枚のプリズムシートは、光源に近い側から、プリズムの延在方向とＣＣＦＬ光源の長手方向に平行、プリズムの延在方向とＣＣＦＬ光源の長手方向に直交させた配置とした。 (Example 3-4)
As shown in FIG. 26 (a), an optical sheet having a prism array formed on the surface and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source, and further above that. Two prism sheets (BEFIII) with the prism extending directions orthogonal to each other and a diffusion sheet having a concavo-convex structure formed by using a speckle pattern formed by interference exposure on the surface are arranged in this order. The light source unit of Example 3-4 was configured. The optical sheet has a prism array (R prism) having a surface with a pitch of 300 μm and a height of 100 μm and a rounded tip, and the R prism forming surface was used as a light exit surface. The two prism sheets were arranged from the side close to the light source in parallel with the extending direction of the prism and the longitudinal direction of the CCFL light source and perpendicular to the extending direction of the prism and the longitudinal direction of the CCFL light source.
　ここで、本発明の光線制御ユニットに係る拡散シートは、拡散角度の最大値が６０°、最小値が０．１°で、図１０（ｂ）に示すように、前記拡散シート面内で滑らかに拡散角度が分布しているような拡散シートを、凹凸面が出光面となるように配置した。また、前記凹凸構造を有する拡散シートは、拡散角度が２０°×１０°の異方性を有するものを、２０°の拡散方向がＣＣＦＬ光源の長手方向と平行になるように配置した。ここで、ＣＣＦＬ光源の径の中心と前記Ｒプリズムが形成された光学シートの入光面との距離ｈを６．３ｍｍとした。実施例３－４の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表１０に併記する。 Here, the diffusion sheet according to the light beam control unit of the present invention has a maximum diffusion angle of 60 ° and a minimum value of 0.1 °, and is smooth within the surface of the diffusion sheet as shown in FIG. A diffusion sheet in which the diffusion angle is distributed is arranged so that the uneven surface becomes the light exit surface. The diffusion sheet having the concavo-convex structure has an anisotropy with a diffusion angle of 20 ° × 10 °, and is arranged so that the diffusion direction of 20 ° is parallel to the longitudinal direction of the CCFL light source. Here, the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the R prism was formed was 6.3 mm. The luminance in the light source unit of Example 3-4 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 10 below.
　（比較例３－５）
実施例３－３の光源ユニットにおいて、本発明の光線制御ユニットに係る拡散シートを使用しないこと以外は、全て同じ構成とし、比較例３－５の光源ユニットを構成した。比較例３－５の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表１０に併記する。 (Comparative Example 3-5)
The light source unit of Example 3-3 has the same configuration except that the diffusion sheet according to the light beam control unit of the present invention is not used, and the light source unit of Comparative Example 3-5 is configured. The luminance in the light source unit of Comparative Example 3-5 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 10 below.
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　表１０より、図２６（ａ）に示す本発明の光線制御ユニット／ＤＳ／プリズムシート／ＤＢＥＦの構成を持つ光源ユニット及び、図２５（ｄ）に示す本発明の光線制御ユニット／プリズムシート／プリズムシート／拡散シートの構成を持つ光源ユニットにおいて、本発明の光線制御ユニットは、シート面内で前記拡散角度が周期的に変化する拡散シートを用いない場合（比較例３－５）と比較して、輝度むらを軽減することができた。 From Table 10, the light source unit having the configuration of the light beam control unit / DS / prism sheet / DBEF of the present invention shown in FIG. 26A and the light beam control unit / prism sheet / prism of the present invention shown in FIG. In a light source unit having a sheet / diffusion sheet configuration, the light beam control unit of the present invention is compared with a case where a diffusion sheet whose diffusion angle periodically changes in the sheet surface is not used (Comparative Example 3-5). , Brightness unevenness could be reduced.
　さらに、比較例３－５の構成において、ＣＣＦＬ光源の径の中心から前記Ｒプリズムが形成された光学シートの入光面までの距離ｈを変化させていくと、ｈ＝１４．６のところで、実施例３－３，３－４と同等の輝度むらとなった。実施例３－３では、ｈ＝８．６、実施例３－４では、ｈ＝６．３であることを考慮すると、比較例３－５に比べて、ＣＣＦＬ光源の径の中心から光学部材の入光面までとの距離ｈを６ｍｍ以上短縮することができ（図２７（ａ））、光源ユニットを薄型化できることがわかる。 Furthermore, in the configuration of Comparative Example 3-5, when the distance h from the center of the diameter of the CCFL light source to the light incident surface of the optical sheet on which the R prism is formed is changed, h = 14.6. The brightness unevenness was the same as in Examples 3-3 and 3-4. Considering that h = 8.6 in Example 3-3 and h = 6.3 in Example 3-4, the optical member from the center of the diameter of the CCFL light source is larger than that in Comparative Example 3-5. It can be seen that the distance h to the light incident surface can be shortened by 6 mm or more (FIG. 27A), and the light source unit can be made thinner.
　実施例３－５及び実施例３－６、比較例３－７及び比較例３－８において、光学シートとして実施例に記載がないものについて、すなわち、反射シート、レンズシート、プリズムシート、反射型偏光シートについては、ソニー社製のＢＲＡＶＩＡ　ＫＤＬ３２－ＪＥ１に使用されている反射シート（以下、ＲＳと略記）、レンズシート（以下、ＤＳと略記）、プリズムシート（ＢＥＦIII（３Ｍ（株）製））、反射型偏光シート（ＤＢＥＦ（３Ｍ（株）製））を用いた。 In Examples 3-5, 3-6, Comparative Examples 3-7, and Comparative Examples 3-8, optical sheets that are not described in the examples, that is, a reflective sheet, a lens sheet, a prism sheet, and a reflective type Regarding the polarizing sheet, a reflective sheet (hereinafter abbreviated as RS), a lens sheet (hereinafter abbreviated as DS), a prism sheet (BEFIII (manufactured by 3M Corporation)) used in BRAVIA KDL32-JE1 manufactured by Sony Corporation A reflective polarizing sheet (DBEF (manufactured by 3M Co., Ltd.)) was used.
　実施例３－５及び実施例３－６、比較例３－７及び比較例３－８については、光源ユニットの光源として、直径３．４ｍｍφ、長さ７１０ｍｍのＣＣＦＬ光源を用いた。前記ＣＣＦＬ光源の長手方向を並列に並べ、ＲＳと前記光源の径の中心との距離を３．７ｍｍとし、前記光源同士の間隔ｐが６３．０ｍｍとなるように６本配置して輝度評価用の光源ユニットを作製した。輝度及び輝度むらは、コニカミノルタ製の２次元色彩輝度計（ＣＡ２０００）を使用し、光源ユニットから７５ｃｍ離して設置し、光源ユニットの中心部２０ｍｍ×１９０ｍｍの範囲で測定した平均輝度値を輝度とした。輝度むらはｘ軸（２０ｍｍ）方向の平均輝度値を求め、ｙ軸方向について、各々の点の輝度値を各々の点から±１１．８ｍｍ分の輝度平均値で割り返した値の標準偏差として輝度むらを求めた。 For Example 3-5, Example 3-6, Comparative Example 3-7, and Comparative Example 3-8, a CCFL light source having a diameter of 3.4 mmφ and a length of 710 mm was used as the light source of the light source unit. The CCFL light sources are arranged in parallel in the longitudinal direction, the distance between the RS and the center of the diameter of the light source is 3.7 mm, and six are arranged so that the distance p between the light sources is 63.0 mm. A light source unit was prepared. Luminance and luminance unevenness were measured using a Konica Minolta two-dimensional color luminance meter (CA2000) at a distance of 75 cm from the light source unit, and the average luminance value measured in the range of 20 mm × 190 mm in the center of the light source unit as luminance. did. The luminance unevenness is obtained as an average luminance value in the x-axis (20 mm) direction, and the standard deviation of the value obtained by dividing the luminance value of each point by the average luminance value of ± 11.8 mm from each point in the y-axis direction. Luminance unevenness was obtained.
　ここで、前記光源ユニットにおいて、目視による輝度むらが許容できるような標準偏差の最大値０．００５を境界とし、輝度むらの判定基準を下記のように２段階（○、×）に分類した。
○：Ｓ．Ｄ．　≦０．００５
×：０．００５＜Ｓ．Ｄ． Here, in the light source unit, the maximum standard deviation 0.005 that can allow the luminance unevenness by visual inspection is used as a boundary, and the determination criterion of the luminance unevenness is classified into two stages (◯, ×) as follows.
○: S. D. ≦ 0.005
X: 0.005 <S. D.
　（実施例３－５）
　図２６（ａ）に示すように、光源から上方に、本発明の光線制御ユニットとして、表面にプリズム条列が形成された光学シート、本発明の拡散シートの順で配置し、さらにその上方に、ＤＳ、プリズムシート（ＢＥＦIII）、反射型偏光シート（ＤＢＥＦ）と、をこの順で配置し、実施例３－５の光源ユニットを構成した。前記光学シートとして、厚さ１．５ｍｍのポリスチレン製で、内部に真比重１．３５、粒径２μｍのシリコーン微粒子を５００ｐｐｍ含有し、出光面にピッチ３００μｍ、高さ１００μｍで、頂点の丸まったプリズム条列（Ｒプリズム）が形成されたもの（旭化成イーマテリアルズ（株）製）を、前記Ｒプリズムの長手方向を、ＣＣＦＬ光源の長手方向と平行に配置した光源ユニットにおいて評価を行った。なお、前記光学シートは、プリズム条列が形成された面を出光面とした。 (Example 3-5)
As shown in FIG. 26 (a), an optical sheet having a prism array formed on the surface and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source, and further above that. DS, prism sheet (BEFIII), and reflective polarizing sheet (DBEF) were arranged in this order to form a light source unit of Example 3-5. As the optical sheet, a prism made of polystyrene having a thickness of 1.5 mm, containing 500 ppm of silicone fine particles having a true specific gravity of 1.35 and a particle diameter of 2 μm inside, a light emitting surface with a pitch of 300 μm, a height of 100 μm and a rounded prism Evaluation was performed on a light source unit in which the longitudinal direction of the R prism was arranged in parallel with the longitudinal direction of the CCFL light source, in which the row (R prism) was formed (manufactured by Asahi Kasei E-Materials Co., Ltd.). In addition, the said optical sheet made the surface in which the prism row | line | column was formed into the light emission surface.
　また、本発明の拡散シートは、拡散角度の最大値が４５°、最小値が７°で、図１０（ｃ）に示すように、前記拡散シート面内で滑らかに拡散角度が分布しているような拡散シートを、凹凸面が出光面となるように配置した。ここで、ＣＣＦＬ光源の径の中心と前記Ｒプリズムが形成された光学シートの入光面との距離ｈを１６．３ｍｍとした。実施例３－５の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表１１に示す。 Further, the diffusion sheet of the present invention has a maximum diffusion angle of 45 ° and a minimum value of 7 °, and the diffusion angle is smoothly distributed in the surface of the diffusion sheet as shown in FIG. 10C. Such a diffusion sheet was disposed such that the uneven surface becomes the light exit surface. Here, the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the R prism was formed was 16.3 mm. The luminance in the light source unit of Example 3-5 was measured, and the luminance unevenness was calculated by the above method. The results are shown in Table 11 below.
　（実施例３－６）
　図２６（ａ）に示すように、光源から上方に、本発明の光線制御ユニットとして、表面にレンチキュラーレンズが形成された光学シート、本発明の拡散シートの順で配置し、さらにその上方に、ＤＳ、プリズムシート（ＢＥＦIII）、反射型偏光シート（ＤＢＥＦ）と、をこの順で配置し、実施例３－６の光源ユニットを構成した。前記光学シートとして、厚さ１．５ｍｍのポリスチレン製で、内部に真比重１．３５、粒径２μｍのシリコーン微粒子を１０００ｐｐｍ含有し、出光面に高さ１３０μｍ、ピッチ３２０μｍのレンチキュラーレンズが形成されたもの（旭化成イーマテリアルズ（株）製）を、前記レンズの長手方向を、ＣＣＦＬ光源の長手方向と平行に配置した光源ユニットにおいて評価を行った。 (Example 3-6)
As shown in FIG. 26 (a), an optical sheet having a lenticular lens formed on the surface thereof and a diffusion sheet of the present invention are arranged in this order as a light beam control unit of the present invention above the light source. DS, a prism sheet (BEFIII), and a reflective polarizing sheet (DBEF) were arranged in this order to constitute a light source unit of Example 3-6. As the optical sheet, a lenticular lens made of polystyrene having a thickness of 1.5 mm, containing 1000 ppm of silicone fine particles having a true specific gravity of 1.35 and a particle size of 2 μm inside, and having a height of 130 μm and a pitch of 320 μm was formed on the light exit surface. The product (manufactured by Asahi Kasei E-Materials Co., Ltd.) was evaluated in a light source unit in which the longitudinal direction of the lens was arranged parallel to the longitudinal direction of the CCFL light source.
　また、本発明の拡散シートは、拡散角度の最大値が３０°、最小値が０．５°で、図２８（ｃ）に示すように、前記拡散シート面内で滑らかに拡散角度が分布しているような拡散シートを、凹凸面が出光面となるように配置した。この拡散シートの拡散角度ピーク値と拡散角度ボトム値との算術平均値（Ａｖ１）は１５°であり、連続する拡散角度ピーク値と拡散角度ボトム値との間に分布する全測定点の拡散角度の算術平均値（Ａｖ２）は１１．７°であった。ここで、ＣＣＦＬ光源の径の中心と前記レンチキュラーレンズが形成された光学シートの入光面との距離ｈを１８．３ｍｍとした。実施例３－６の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表１１に併記する。 Further, the diffusion sheet of the present invention has a maximum diffusion angle of 30 ° and a minimum value of 0.5 °, and the diffusion angle is smoothly distributed in the surface of the diffusion sheet as shown in FIG. The diffusion sheet as described above was arranged so that the uneven surface became the light exit surface. The arithmetic average value (Av1) of the diffusion angle peak value and the diffusion angle bottom value of this diffusion sheet is 15 °, and the diffusion angles at all measurement points distributed between the continuous diffusion angle peak value and the diffusion angle bottom value. The arithmetic average value (Av2) of was 11.7 °. Here, the distance h between the center of the diameter of the CCFL light source and the light incident surface of the optical sheet on which the lenticular lens was formed was 18.3 mm. The luminance in the light source unit of Example 3-6 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 11 below.
　（比較例３－７）
　実施例３－５の光源ユニットにおいて、本発明の光線制御ユニットに係る拡散シートを使用しないこと以外は、全て同じ構成とし、比較例３－７の光源ユニットを構成した。比較例３－７の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表１１に併記する。 (Comparative Example 3-7)
The light source unit of Example 3-5 has the same configuration except that the diffusion sheet according to the light beam control unit of the present invention is not used, and the light source unit of Comparative Example 3-7 is configured. The luminance in the light source unit of Comparative Example 3-7 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 11 below.
　（比較例３－８）
実施例３－６の光源ユニットにおいて、本発明の光線制御ユニットに係る拡散シートを使用しないこと以外は、全て同じ構成とし、比較例３－８の光源ユニットを構成した。比較例３－８の光源ユニットにおける輝度を測定し、輝度むらを上記の方法で算出した。その結果を下記表１１に併記する。 (Comparative Example 3-8)
The light source unit of Example 3-6 has the same configuration except that the diffusion sheet according to the light beam control unit of the present invention is not used, and the light source unit of Comparative Example 3-8 is configured. The luminance in the light source unit of Comparative Example 3-8 was measured, and the luminance unevenness was calculated by the above method. The results are also shown in Table 11 below.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
　表１１より、図２６（ａ）に示す本発明の光線制御ユニット／ＤＳ／プリズムシート／ＤＢＥＦの構成を持つ光源ユニットにおいて、輝度むらを軽減することができた。 From Table 11, the luminance unevenness could be reduced in the light source unit having the configuration of the light beam control unit / DS / prism sheet / DBEF of the present invention shown in FIG.
　さらに、比較例３－７，３－８の構成において、ＣＣＦＬ光源の間隔ｐを変化させていくと、ｐ＝４７．６のところで、実施例３－５，３－６と同等の輝度むらとなった。実施例３－５，３－６では、ｐ＝６３．０であることを考慮すると、比較例３－７，３－８に比べて、ＣＣＦＬ光源の間隔ｐを１５．４ｍｍ拡大することができ（図２７（ｂ））、光源ユニットの光源数を削減できることがわかる。 Further, in the configurations of Comparative Examples 3-7 and 3-8, when the interval p of the CCFL light source is changed, luminance unevenness equivalent to that of Examples 3-5 and 3-6 is obtained at p = 47.6. became. In Examples 3-5 and 3-6, considering that p = 63.0, the distance p between CCFL light sources can be increased by 15.4 mm compared to Comparative Examples 3-7 and 3-8. (FIG. 27B), it can be seen that the number of light sources of the light source unit can be reduced.
　本発明は上記実施の形態に限定されず、種々変更して実施することが可能である。例えば、上記実施の形態における部材の材質、配置、形状などは例示的なものであり、適宜変更して実施することが可能である。また、上記実施の形態１、２で示した構成を適宜組み合わせて光源ユニットを構成することができる。その他、本発明の範囲を逸脱しない限りにおいて適宜変更して実施することが可能である。 The present invention is not limited to the above embodiment, and can be implemented with various modifications. For example, the material, arrangement, shape, and the like of the members in the above embodiment are illustrative, and can be implemented with appropriate changes. Further, the light source unit can be configured by appropriately combining the configurations shown in the first and second embodiments. In addition, various modifications can be made without departing from the scope of the present invention.
　本発明は、液晶表示装置のような表示デバイスの拡散シート、光線制御ユニット、光源ユニットに有効である。 The present invention is effective for a diffusion sheet, a light beam control unit, and a light source unit of a display device such as a liquid crystal display device.
　本出願は、２００９年３月９日出願の特願２００９－０５５５２０、２００９年３月９日出願の特願２００９－０５５６３５及び２００９年３月３０日出願の特願２００９－０８２７３６に基づく。これらの内容は、全てここに含めておく。 This application is based on Japanese Patent Application No. 2009-055520 filed on March 9, 2009, Japanese Patent Application No. 2009-055635 filed on March 9, 2009, and Japanese Patent Application No. 2009-082736 filed on March 30, 2009. All these contents are included here.

Claims (55)

  1. 　シート面に垂直に光線を入射した場合の出射光の拡散角度が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置での拡散角度を縦軸にとった拡散角度分布図において、前記拡散角度のピーク値と前記拡散角度のボトム値とが複数有り、隣り合う前記ピーク値と前記ボトム値との間の拡散角度の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点における拡散角度の算術平均値より大きいことを特徴とする拡散シート。 A diffusion sheet in which a diffusion angle of emitted light when a light beam is incident perpendicularly to a sheet surface periodically changes along a predetermined direction in the sheet surface, and the relative in the sheet surface in the predetermined direction In the diffusion angle distribution diagram in which the position is taken on the horizontal axis and the diffusion angle at the relative position in the sheet surface is taken on the vertical axis, there are a plurality of peak values of the diffusion angle and bottom values of the diffusion angle, and the adjacent The arithmetic average value of the diffusion angles between the peak value and the bottom value is larger than the arithmetic average value of the diffusion angles at all points distributed between the adjacent peak value and the bottom value. Diffusion sheet.
  2. 　シート面に垂直に光線を入射した場合の出射光の拡散角度が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置での拡散角度を縦軸にとった拡散角度分布図において、一つの高拡散角度領域に複数のピーク値を含むことを特徴とする拡散シート。 A diffusion sheet in which a diffusion angle of outgoing light when a light beam is incident perpendicularly to a sheet surface periodically changes along a predetermined direction in the sheet surface, and the relative in the sheet surface in the predetermined direction A diffusion sheet comprising a plurality of peak values in one high diffusion angle region in a diffusion angle distribution chart in which a horizontal axis represents a position and a vertical axis represents a diffusion angle at a relative position in the sheet surface.
  3. 　前記高拡散角度領域における隣接するピーク間の拡散角度分布が直線状であることを特徴とする請求項２に記載の拡散シート。 The diffusion sheet according to claim 2, wherein a diffusion angle distribution between adjacent peaks in the high diffusion angle region is linear.
  4. 　前記高拡散角度領域における隣接するピーク間の拡散角度分布が、下に凸の曲線状または曲線と直線の混合形状であることを特徴とする請求項２に記載の拡散シート。 The diffusion sheet according to claim 2, wherein the diffusion angle distribution between adjacent peaks in the high diffusion angle region is a downward convex curve shape or a mixed shape of a curve and a straight line.
  5. 　シート面に垂直に光線を入射した場合の出射光の拡散角度が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置での拡散角度を縦軸にとった拡散角度分布図において、前記拡散角度のボトム値があり、前記ボトム値を含む低拡散角度領域における拡散角度分布が、前記ボトム値を極小値とする下に凸の曲線状であることを特徴とする拡散シート。 A diffusion sheet in which a diffusion angle of outgoing light when a light beam is incident perpendicularly to a sheet surface periodically changes along a predetermined direction in the sheet surface, and the relative in the sheet surface in the predetermined direction In the diffusion angle distribution diagram in which the position is taken on the horizontal axis and the diffusion angle at the relative position in the sheet surface is taken on the vertical axis, there is a bottom value of the diffusion angle, and the diffusion angle in the low diffusion angle region including the bottom value The diffusion sheet is characterized in that the distribution is a downwardly convex curve with the bottom value as a minimum value.
  6. 　前記拡散角度のピーク値と前記拡散角度のボトム値とを交互に周期的に有し、隣り合う前記ピーク値と前記ボトム値との２点における拡散角度の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点における拡散角度の算術平均値より大きく、かつ拡散角度の分布が前記ピーク値を含み上に凸の曲線形状を有する第一の区間と、拡散角度の分布が前記ボトム値を含み下に凸の曲線形状を有する第二の区間とを有することを特徴とする請求項１、請求項２、請求項５のいずれかに記載の拡散シート。 The peak value of the diffusion angle and the bottom value of the diffusion angle alternately and periodically, and the arithmetic average value of the diffusion angles at two points of the adjacent peak value and the bottom value is the adjacent peak. A first interval that is larger than the arithmetic average value of the diffusion angles at all points distributed between the value and the bottom value, and the distribution of the diffusion angles includes the peak value and has an upward convex curve shape, and the diffusion angle 6. The diffusion sheet according to claim 1, wherein the distribution sheet includes a second section including the bottom value and having a downwardly convex curved shape.
  7. 　前記拡散角度分布図において、全領域における拡散角度が０．１°以上１２０°以下の範囲内であることを特徴とする請求項１から請求項６のいずれかに記載の拡散シート。 The diffusion sheet according to any one of claims 1 to 6, wherein in the diffusion angle distribution diagram, a diffusion angle in the entire region is in a range of 0.1 ° to 120 °.
  8. 　前記拡散角度分布図における拡散角度の最小値が、０．１°以上４０°以下であることを特徴とする請求項１から請求項７のいずれかに記載の拡散シート。 The diffusion sheet according to any one of claims 1 to 7, wherein a minimum value of a diffusion angle in the diffusion angle distribution diagram is 0.1 ° or more and 40 ° or less.
  9. 　前記拡散角度の最大値と最小値との差が４０°以上８０°以下であることを特徴とする請求項１から請求項８のいずれかに記載の拡散シート。 The diffusion sheet according to any one of claims 1 to 8, wherein a difference between a maximum value and a minimum value of the diffusion angle is 40 ° or more and 80 ° or less.
  10. 　前記拡散角度は、前記拡散シート面に形成された凹凸構造により生じることを特徴とする請求項１から請求項９のいずれかに記載の拡散シート。 The diffusion sheet according to any one of claims 1 to 9, wherein the diffusion angle is generated by an uneven structure formed on the surface of the diffusion sheet.
  11. 　シート面に設けられた凹凸構造のアスペクト比が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置でのアスペクト比を縦軸にとったアスペクト比分布図において、前記アスペクト比のピーク値と前記アスペクト比のボトム値とが複数有り、隣り合う前記ピーク値と前記ボトム値との間のアスペクト比の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点におけるアスペクト比の算術平均値より大きいことを特徴とする拡散シート。 A diffusion sheet in which an aspect ratio of a concavo-convex structure provided on a sheet surface periodically changes along a predetermined direction in the sheet surface, and a horizontal axis indicates a relative position in the sheet surface in the predetermined direction. In the aspect ratio distribution diagram in which the vertical axis represents the aspect ratio at the relative position in the sheet surface, there are a plurality of peak values of the aspect ratio and bottom values of the aspect ratio, and the adjacent peak value and the bottom A diffusion sheet, wherein an arithmetic average value of aspect ratios between values is larger than an arithmetic average value of aspect ratios at all points distributed between the adjacent peak value and the bottom value.
  12. 　シート面に設けられた凹凸構造のアスペクト比が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置でのアスペクト比を縦軸にとったアスペクト比分布図において、一つの高アスペクト比領域に複数のピーク値を含むことを特徴とする拡散シート。 A diffusion sheet in which an aspect ratio of a concavo-convex structure provided on a sheet surface periodically changes along a predetermined direction in the sheet surface, and a horizontal axis indicates a relative position in the sheet surface in the predetermined direction. A diffusion sheet comprising a plurality of peak values in one high aspect ratio region in an aspect ratio distribution diagram in which the vertical axis represents the aspect ratio at a relative position in the sheet surface.
  13. 　前記高アスペクト比領域における隣接するピーク間のアスペクト比分布が直線状であることを特徴とする請求項１２に記載の拡散シート。 The diffusion sheet according to claim 12, wherein the aspect ratio distribution between adjacent peaks in the high aspect ratio region is linear.
  14. 　前記高アスペクト比領域における隣接するピーク間のアスペクト比分布が、下に凸の曲線状または曲線と直線の混合形状であることを特徴とする請求項１２に記載の拡散シート。 The diffusion sheet according to claim 12, wherein the aspect ratio distribution between adjacent peaks in the high aspect ratio region is a downward convex curve or a mixed shape of a curve and a straight line.
  15. 　シート面に設けられた凹凸構造のアスペクト比が前記シート面内の所定の方向に沿って周期的に変化する拡散シートであって、前記所定の方向における前記シート面内の相対位置を横軸にとり、前記シート面内の相対位置でのアスペクト比を縦軸にとったアスペクト比分布図において、前記アスペクト比のボトム値があり、前記ボトム値を含む低アスペクト比領域におけるアスペクト比分布が、前記ボトム値を極小値とする下に凸の曲線状であることを特徴とする拡散シート。 A diffusion sheet in which an aspect ratio of a concavo-convex structure provided on a sheet surface periodically changes along a predetermined direction in the sheet surface, and a horizontal axis indicates a relative position in the sheet surface in the predetermined direction. In the aspect ratio distribution diagram in which the vertical axis represents the aspect ratio at the relative position in the sheet surface, there is a bottom value of the aspect ratio, and the aspect ratio distribution in the low aspect ratio region including the bottom value is the bottom A diffusion sheet characterized by a downwardly convex curved shape having a minimum value.
  16. 　前記アスペクト比分布のピーク値と前記アスペクト比分布のボトム値とを交互に周期的に有し、隣り合う前記ピーク値と前記ボトム値との２点におけるアスペクト比分布の算術平均値が、前記隣り合う前記ピーク値と前記ボトム値との間に分布する全点におけるアスペクト比分布の算術平均値より大きく、かつアスペクト比分布が前記ピーク値を含み上に凸の曲線形状を有する第一の区間と、アスペクト比分布が前記ボトム値を含み下に凸の曲線形状を有する第二の区間とを有することを特徴とする請求項１１、請求項１２、請求項１５のいずれかに記載の拡散シート。 The peak value of the aspect ratio distribution and the bottom value of the aspect ratio distribution are periodically and alternately, and the arithmetic average value of the aspect ratio distribution at two points of the adjacent peak value and the bottom value is the adjacent value. A first interval having a convex shape that is larger than the arithmetic average value of the aspect ratio distribution at all points distributed between the peak value and the bottom value, and the aspect ratio distribution includes the peak value and has an upward convex shape; The diffusion sheet according to any one of claims 11, 12, and 15, wherein the aspect ratio distribution includes a second section including the bottom value and having a downwardly convex curved shape.
  17. 　前記凹凸構造の高さが変化することによって、前記アスペクト比が変化する形状を有することを特徴とする請求項１１から請求項１６のいずれかに記載の拡散シート。 The diffusion sheet according to any one of claims 11 to 16, wherein the diffusion sheet has a shape in which the aspect ratio changes as the height of the uneven structure changes.
  18. 　前記凹凸構造のピッチが変化することによって、前記アスペクト比が変化する形状を有することを特徴とする請求項１１から請求項１６のいずれかに記載の拡散シート。 The diffusion sheet according to any one of claims 11 to 16, wherein the diffusion sheet has a shape in which the aspect ratio changes as the pitch of the uneven structure changes.
  19. 　前記凹凸構造が干渉露光によるスペックルパターンを用いて形成された凹凸構造であることを特徴とする請求項１０から請求項１８のいずれかに記載の拡散シート。 The diffusion sheet according to any one of claims 10 to 18, wherein the concavo-convex structure is a concavo-convex structure formed using a speckle pattern by interference exposure.
  20. 　２つ以上の光源と、前記光源の上方に配設される請求項１から請求項１９のいずれかに記載の拡散シートと、を備えることを特徴とする光源ユニット。 20. A light source unit comprising two or more light sources and the diffusion sheet according to any one of claims 1 to 19 disposed above the light sources.
  21. 　前記光源は線状光源であることを特徴とする請求項２０に記載の光源ユニット。 The light source unit according to claim 20, wherein the light source is a linear light source.
  22. 　前記光源は点状光源であることを特徴とする請求項２０に記載の光源ユニット。 The light source unit according to claim 20, wherein the light source is a point light source.
  23. 　前記拡散シートの拡散角度分布の周期と、前記拡散シートの入光面における照度分布の周期とが略等しいことを特徴とする請求項２０に記載の光源ユニット。 21. The light source unit according to claim 20, wherein a period of the diffusion angle distribution of the diffusion sheet is substantially equal to a period of the illuminance distribution on the light incident surface of the diffusion sheet.
  24. 　前記拡散シートと光源の間に配置され、内部に拡散剤を含有する拡散板と、前記光源の下方に配置される反射シートと、を備えることを特徴とする請求項２０に記載の光源ユニット。 21. The light source unit according to claim 20, further comprising: a diffusion plate disposed between the diffusion sheet and the light source and containing a diffusing agent therein; and a reflection sheet disposed below the light source.
  25. 　前記拡散シートの上方に配置されるレンズシートを備えることを特徴とする請求項２０記載の光源ユニット。 21. The light source unit according to claim 20, further comprising a lens sheet disposed above the diffusion sheet.
  26. 　前記拡散シートの上方に配置されるプリズムシートを備えることを特徴とする請求項２０に記載の光源ユニット。 21. The light source unit according to claim 20, further comprising a prism sheet disposed above the diffusion sheet.
  27. 　前記拡散シート上方に配置される反射型偏光シートを備えることを特徴とする請求項２０に記載の光源ユニット。 21. The light source unit according to claim 20, further comprising a reflective polarizing sheet disposed above the diffusion sheet.
  28. 　表面に複数のレンズにより構成されたレンズ部が形成された光学シートを有し、前記光学シートの表面側に、前記拡散シートが配置されていることを特徴とする請求項２０に記載の光源ユニット。 21. The light source unit according to claim 20, further comprising: an optical sheet having a lens portion formed by a plurality of lenses formed on a surface thereof, wherein the diffusion sheet is disposed on a surface side of the optical sheet. .
  29. 　前記光学シートの前記レンズ部が、単位レンズを複数配列することにより構成されており、かつ前記単位レンズの底面形状が異方性を有する形状であることを特徴とする請求項２８に記載の光源ユニット。 29. The light source according to claim 28, wherein the lens portion of the optical sheet is configured by arranging a plurality of unit lenses, and a bottom surface shape of the unit lenses is a shape having anisotropy. unit.
  30. 　前記単位レンズの底面形状が、楕円形又は長方形であることを特徴とする請求項２９に記載の光源ユニット。 The light source unit according to claim 29, wherein a bottom shape of the unit lens is an ellipse or a rectangle.
  31. 　前記単位レンズが、レンチキュラーレンズ又はプリズム条列であることを特徴とする請求項２９に記載の光源ユニット。 The light source unit according to claim 29, wherein the unit lens is a lenticular lens or a prism array.
  32. 　前記光学シートの前記レンズ部が、単位レンズを複数配列することにより構成されており、かつ前記単位レンズの底面形状が等方性を有する形状であることを特徴とする請求項２８に記載の光源ユニット。 29. The light source according to claim 28, wherein the lens portion of the optical sheet is configured by arranging a plurality of unit lenses, and a bottom surface shape of the unit lenses is an isotropic shape. unit.
  33. 　前記単位レンズの底面形状が、円形、正方形、正６角形であることを特徴とする請求項３２に記載の光源ユニット。 The light source unit according to claim 32, wherein a bottom shape of the unit lens is a circle, a square, or a regular hexagon.
  34. 　前記単位レンズが、マイクロレンズ又はマイクロプリズムであることを特徴とする請求項２９、請求項３０、請求項３２、請求項３３のいずれかに記載の光源ユニット。 The light source unit according to any one of claims 29, 30, 32, and 33, wherein the unit lens is a microlens or a microprism.
  35. 　前記光学シートの前記レンズ部が、底面形状が異方性を有する形状のレンズと、等方性を有する形状のレンズとを配列することにより構成されていることを特徴とする請求項２８に記載の光源ユニット。 The lens part of the optical sheet is configured by arranging a lens having a shape with a bottom surface having anisotropy and a lens having an isotropic shape. Light source unit.
  36. 　液晶表示パネルと、前記液晶表示パネルに光を供給する請求項２０から請求項３５のいずれかに記載の光源ユニットと、を備えることを特徴とする液晶表示装置。 A liquid crystal display device comprising: a liquid crystal display panel; and the light source unit according to any one of claims 20 to 35 that supplies light to the liquid crystal display panel.
  37. 　光源からの光を入光する入光面と、前記入光面から入光した光を出光する出光面と、を有し、表面に複数のレンズにより構成されたレンズ部が形成された光学シートと、前記光学シートのシート面に垂直に光線を入射した場合に、前記シート面内の所定の方向に沿って拡散角度が周期的に変化する拡散シートと、を備えたことを特徴とする光線制御ユニット。 An optical sheet having a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface, and having a lens portion formed of a plurality of lenses on the surface. And a diffusion sheet whose diffusion angle changes periodically along a predetermined direction in the sheet surface when the light beam enters perpendicularly to the sheet surface of the optical sheet. Controller unit.
  38. 　光源からの光を入光する入光面と、前記入光面から入光した光を出光する出光面と、を有し、表面に複数のレンズにより構成されたレンズ部が形成された光学シートと、前記光学シートのシート面に垂直に光線を入射した場合に、前記シート面内の所定の方向に沿ってシート面に設けられた凹凸構造のアスペクト比が周期的に変化する拡散シートと、を備えたことを特徴とする光線制御ユニット。 An optical sheet having a light incident surface that receives light from a light source and a light output surface that emits light incident from the light incident surface, and having a lens portion formed of a plurality of lenses on the surface. And a diffusion sheet in which the aspect ratio of the concavo-convex structure provided on the sheet surface changes periodically along a predetermined direction in the sheet surface when a light beam is incident perpendicular to the sheet surface of the optical sheet, A light beam control unit comprising:
  39. 　前記光学シートの前記表面側に、前記拡散シートが配置されていることを特徴とする請求項３７又は請求項３８に記載の光線制御ユニット。 The light beam control unit according to claim 37 or 38, wherein the diffusion sheet is disposed on the surface side of the optical sheet.
  40. 　前記光学シートの前記レンズ部が、単位レンズを複数配列することにより構成されており、かつ前記単位レンズの底面形状が異方性を有する形状であることを特徴とする請求項３７から請求項３９のいずれかに記載の光線制御ユニット。 The lens section of the optical sheet is configured by arranging a plurality of unit lenses, and the bottom surface shape of the unit lenses is a shape having anisotropy. The light beam control unit according to any one of the above.
  41. 　前記単位レンズの底面形状が、楕円形又は長方形であることを特徴とする請求項４０に記載の光線制御ユニット。 41. The light beam control unit according to claim 40, wherein a bottom shape of the unit lens is an ellipse or a rectangle.
  42. 　前記単位レンズが、レンチキュラーレンズ又はプリズム条列であることを特徴とする請求項４０に記載の光線制御ユニット。 41. The light beam control unit according to claim 40, wherein the unit lens is a lenticular lens or a prism array.
  43. 　前記光学シートの前記レンズ部が、単位レンズを複数配列することにより構成されており、かつ前記単位レンズの底面形状が等方性を有する形状であることを特徴とする請求項３７から請求項３９のいずれかに記載の光線制御ユニット。 The lens portion of the optical sheet is configured by arranging a plurality of unit lenses, and the bottom surface shape of the unit lens is an isotropic shape. The light beam control unit according to any one of the above.
  44. 　前記単位レンズの底面形状が、円形、正方形、正６角形であることを特徴とする請求項４３に記載の光線制御ユニット。 44. The light beam control unit according to claim 43, wherein a bottom shape of the unit lens is a circle, a square, or a regular hexagon.
  45. 　前記単位レンズが、マイクロレンズ又はマイクロプリズムであることを特徴とする請求項４０、請求項４１、請求項４３、請求項４４のいずれかに記載の光線制御ユニット。 The light beam control unit according to any one of claims 40, 41, 43, and 44, wherein the unit lens is a microlens or a microprism.
  46. 　前記光学シートの前記レンズ部が、底面形状が異方性を有する形状のレンズと、等方性を有する形状のレンズとを配列することにより構成されていることを特徴とする請求項３７から請求項３９のいずれかに記載の光線制御ユニット。 The lens portion of the optical sheet is configured by arranging a lens having a shape having anisotropy in the bottom surface and a lens having an isotropic shape. Item 40. The light beam control unit according to any one of Items 39.
  47. 　前記拡散シートの拡散角度が、０．１°以上１２０°以下の範囲内であることを特徴とする請求項３７から請求項４６のいずれかに記載の光線制御ユニット。 The light beam control unit according to any one of claims 37 to 46, wherein a diffusion angle of the diffusion sheet is in a range of 0.1 ° to 120 °.
  48. 　前記拡散角度は、前記拡散シートの表面に形成された凹凸構造により生じることを特徴とする請求項３７から請求項４７のいずれかに記載の光線制御ユニット。 The light beam control unit according to any one of claims 37 to 47, wherein the diffusion angle is generated by an uneven structure formed on a surface of the diffusion sheet.
  49. 　前記凹凸構造が干渉露光によるスペックルパターンを用いて形成されていることを特徴とする請求項４８に記載の光線制御ユニット。 The light beam control unit according to claim 48, wherein the concavo-convex structure is formed using a speckle pattern by interference exposure.
  50. 　２つ以上の光源と、前記光源の上方に配設される請求項３７から請求項４９のいずれかに記載の光線制御ユニットと、を備えることを特徴とする光源ユニット。 A light source unit comprising two or more light sources and the light beam control unit according to any one of claims 37 to 49 disposed above the light sources.
  51. 　前記拡散シートの拡散角度分布の周期と、前記拡散シートの入光面における照度分布の周期とを略等しくしたことを特徴とする請求項５０に記載の光源ユニット。 51. The light source unit according to claim 50, wherein a period of the diffusion angle distribution of the diffusion sheet is substantially equal to a period of the illuminance distribution on the light incident surface of the diffusion sheet.
  52. 　前記光源の下方に配置された反射シートを備えることを特徴とする請求項５０又は請求項５１に記載の光源ユニット。 52. The light source unit according to claim 50 or 51, further comprising a reflective sheet disposed below the light source.
  53. 　前記拡散シート上方に配置されるプリズムシートを備えることを特徴とする請求項５０から請求項５２のいずれかに記載の光源ユニット。 The light source unit according to any one of claims 50 to 52, further comprising a prism sheet disposed above the diffusion sheet.
  54. 　前記拡散シート上方に配置される反射型偏光シートを備えることを特徴とする請求項５０から請求項５３のいずれかに記載の光源ユニット。 54. The light source unit according to claim 50, further comprising a reflective polarizing sheet disposed above the diffusion sheet.
  55. 　液晶表示パネルと、前記液晶表示パネルに光を供給する請求項５０から請求項５４のいずれかに記載の光源ユニットと、を備えることを特徴とする液晶表示装置。 A liquid crystal display device comprising: a liquid crystal display panel; and the light source unit according to any one of claims 50 to 54 for supplying light to the liquid crystal display panel.
PCT/JP2010/053823 2009-03-09 2010-03-08 Diffusion sheet, light control unit, and light source unit WO2010104051A1 (en)

Applications Claiming Priority (6)

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JP2009055635A JP2010210828A (en) 2009-03-09 2009-03-09 Diffusion sheet
JP2009055520 2009-03-09
JP2009-055635 2009-03-09
JP2009-055520 2009-03-09
JP2009082736 2009-03-30
JP2009-082736 2009-03-30

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WO2013099839A1 (en) * 2011-12-27 2013-07-04 シャープ株式会社 Liquid crystal display device, light control film, and display device
TWI614533B (en) * 2016-02-01 2018-02-11 群睿股份有限公司 Three-dimensional display device
CN111239869B (en) * 2020-03-19 2022-02-22 宁波舜宇车载光学技术有限公司 Diffusion plate

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JP2006106562A (en) * 2004-10-08 2006-04-20 Radiant Opt-Electronics Corp Diffuser plate, direct back light module and manufacturing method of the diffuser plate
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JP2007003852A (en) * 2005-06-24 2007-01-11 Sony Corp Diffusion sheet, method for manufacturing diffusion sheet, backlight device and liquid crystal display device

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JP2001023422A (en) * 1999-07-02 2001-01-26 Konsho Ryo Flat plate lighting system and manufacture of its hologram photo-guide plate
JP2006106562A (en) * 2004-10-08 2006-04-20 Radiant Opt-Electronics Corp Diffuser plate, direct back light module and manufacturing method of the diffuser plate
JP2006220778A (en) * 2005-02-09 2006-08-24 Sharp Corp Backlight device, and display device equipped therewith
JP2007003852A (en) * 2005-06-24 2007-01-11 Sony Corp Diffusion sheet, method for manufacturing diffusion sheet, backlight device and liquid crystal display device

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