WO2010050522A1 - Feuille optique, procédé de fabrication de feuille optique, source lumineuse incluant la feuille optique et dispositif d'affichage - Google Patents

Feuille optique, procédé de fabrication de feuille optique, source lumineuse incluant la feuille optique et dispositif d'affichage Download PDF

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Publication number
WO2010050522A1
WO2010050522A1 PCT/JP2009/068522 JP2009068522W WO2010050522A1 WO 2010050522 A1 WO2010050522 A1 WO 2010050522A1 JP 2009068522 W JP2009068522 W JP 2009068522W WO 2010050522 A1 WO2010050522 A1 WO 2010050522A1
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WO
WIPO (PCT)
Prior art keywords
optical sheet
shape
lens
unit lens
line
Prior art date
Application number
PCT/JP2009/068522
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English (en)
Japanese (ja)
Inventor
大資 今井
祐輝 三吉
敏夫 淡路
Original Assignee
株式会社日本触媒
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Application filed by 株式会社日本触媒 filed Critical 株式会社日本触媒
Priority to CN2009801432461A priority Critical patent/CN102197324A/zh
Publication of WO2010050522A1 publication Critical patent/WO2010050522A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0012—Arrays characterised by the manufacturing method
    • G02B3/0031—Replication or moulding, e.g. hot embossing, UV-casting, injection moulding
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G02B5/0268—Diffusing elements; Afocal elements characterized by the fabrication or manufacturing method
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/0074—Production of other optical elements not provided for in B29D11/00009- B29D11/0073
    • B29D11/00788—Producing optical films
    • 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
    • G02B3/0043—Inhomogeneous or irregular arrays, e.g. varying shape, size, height
    • 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
    • G02B5/021—Diffusing elements; Afocal elements characterised by the diffusing properties the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/0035—Means for improving the coupling-out of light from the light guide provided on the surface of the light guide or in the bulk of it
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0053—Prismatic sheet or layer; Brightness enhancement element, sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—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
    • G02F1/133606—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 an optical sheet, a method for manufacturing the optical sheet, a light source device including the optical sheet, and a display device.
  • the light source of the liquid crystal display device includes an edge light type and a direct type, but a large type liquid crystal display device generally uses a direct type light source in which a plurality of cold cathode tubes are arranged as the light source.
  • the portion where the cold-cathode tube is present is bright, while the portion where the cold-cathode tube is not present is relatively dark, resulting in uneven brightness. There is a problem of being reflected in. Therefore, by arranging various optical sheets between the cold cathode fluorescent lamp and the liquid crystal panel, light emitted from the cold cathode fluorescent lamp is uniformly diffused over the entire screen.
  • Liquid crystal display devices are required to be further thinned. For this reason, the distance between the cold cathode fluorescent lamp and the screen has to be narrowed, and it has become difficult to sufficiently diffuse the light from the cold cathode fluorescent lamp. . Further, in order to reduce the cost, the number of cold cathode tubes is also reduced, and it is difficult to uniformly diffuse light from the cold cathode tubes as the interval between the cold cathode tubes is increased. Therefore, under such severe conditions, as a method of eliminating luminance unevenness and improving luminance, select an optical sheet with a lens as the optical sheet placed closest to the light source and adjust the lens shape. Has been done.
  • At least one prism sheet is selected as the second and subsequent optical sheets with respect to the direction from the light source to the liquid crystal panel.
  • a plurality of prism lenses having a triangular cross section are arranged in parallel.
  • a prism sheet or a lenticular lens sheet in which a plurality of cylindrical lenses having a cylindrical convex surface are arranged in parallel is used as an alternative to a conventional optical sheet.
  • Prism sheets and lenticular lens sheets can prevent the amount of transmitted light from decreasing and the brightness in the viewing angle direction because the number of incident rays repeats catadioptric refraction is less than optical sheets with conventional light diffusing agents. Can be improved.
  • the prism sheet can improve the luminance, there is a limit to the uniform distribution thereof.
  • the lenticular lens sheet can also increase the uniformity of the luminance distribution as compared with the prism sheet, it is difficult to completely eliminate the luminance unevenness under the severe cold cathode tube installation conditions as described above.
  • An optical sheet having lenses arranged in a straight bowl on the light exit surface is arranged at a position closest to the light source, and at least one prism is provided on the optical sheet arranged second or later in the direction from the light source to the liquid crystal panel.
  • the light diffusibility is enhanced by the effect of the prism, and the front luminance can be increased. Therefore, it is considered to be an optical sheet configuration for a light source that is optimal for thinning a liquid crystal television and reducing the number of cold cathode tubes.
  • An object of the present invention is to reduce luminance unevenness at an intermediate point between line light sources (for example, cold-cathode tubes) arranged in parallel with each other and directly above the line light source, and to be arranged second or later in the direction from the light source to the liquid crystal panel. It is to provide an optical sheet capable of obtaining a uniform luminance distribution by combination with the optical sheet, a manufacturing method of the optical sheet, a light source device including them, and a liquid crystal display device.
  • line light sources for example, cold-cathode tubes
  • the inventors have obtained a cross section perpendicular to the length direction of the lens group in the lens group formed in a linear bowl shape on the surface of the optical sheet.
  • the outer peripheral line of the convex part of all the lenses in the shape is composed of a curve and / or a straight line, and the tangent line of the curve and / or the angle formed by the straight line and the base line adjusts the ratio of the part within a specific range.
  • the optical sheet of the present invention is an optical sheet having a convex lens group formed on the surface in the form of a straight bowl, and the convex parts of all the lenses in a cross-sectional shape perpendicular to the length direction of the lens group.
  • a portion (X 1 ) in which the outer peripheral line is composed of a curve and / or a straight line and the angle ( ⁇ ) between the tangent and / or the straight line and the base line at all points on the curve is ⁇ ⁇ 40 °
  • a portion (X 2 ) where an angle ( ⁇ ) formed between a tangent at all points on the curve and / or the straight line and a base line is 25 ° ⁇ ⁇ ⁇ 35 °
  • the total length (x 1total ) of the length (x 1 ) projected on the base line of the lens group is 25% or more and 60% or less of the total length (P total ) of the base line length of the lens group
  • said portion (X 2) the lens group length projected in baseline of (x 2 Total (x 2total), characterized in that the total length of the lens group of the base line is 60% or less 25% or more (P total).
  • the lens group is configured such that the convex outer peripheral line in the vertical cross-sectional shape with respect to the length direction of the unit lens is mainly composed of a curve, and tangents at all points on the curve and the angle of the baseline (theta 11) is the theta 11 ⁇ 40 ° curved section and (R 11), the tangent angle of the base line at all points on the curve (theta 12) is 25 ° ⁇ theta
  • the ratio of the total length (r 11 ) of the curved portion (R 11 ) projected onto the base line of the unit lens shape to the total length of the base line includes the curved portion (R 12 ) satisfying 12 ⁇ 35 °.
  • the ratio of the total length (r 12 ) of the curved portion (R 12 ) projected onto the base line of the unit lens shape to the total length of the base line is 25% or more and 60% or less.
  • % Is an optical sheet having a first unit lens (see FIG. 6) that is less than or equal to%.
  • the lens group is formed of a shape in which the convex portion outer peripheral line in the vertical cross-sectional shape with respect to the length direction of the unit lens is formed by connecting two or more curves and one or more straight lines.
  • the curves include a curve portion (R 21 ) in which an angle ( ⁇ 21 ) between a tangent line and a base line at all points on the curve is ⁇ 21 ⁇ 40 °, and the straight line (R 22 ) and a base line ( ⁇ 22 ) is an optical sheet having a second unit lens (see FIGS. 7 to 10) in which 25 ° ⁇ ⁇ 22 ⁇ 35 °.
  • the lens group includes a unit lens (see FIG. 12) having the following shape 1 and a unit lens having the shape 2 as a convex portion outer peripheral line having a vertical cross-sectional shape with respect to the length direction. It is an optical sheet having (see FIG. 13).
  • ⁇ Shape 1 ⁇ A portion in which an outer peripheral line is a curve or a straight line, and an angle ( ⁇ 32 ) between a tangent or a straight line at all points on the curve and a base line of the unit lens cross-sectional shape is 25 ° ⁇ ⁇ 32 ⁇ 35 ° (R 32 ), and the total length (r 32 ) of the portion (R 32 ) projected onto the base line of the unit lens cross-sectional shape is 90% or more with respect to the total base line length of the unit lens cross-sectional shape A shape characterized by ⁇ Shape 2 ⁇
  • the total length (r 33 ) projected on the base line of the unit lens shape of the portion (R 33 ) whose outer peripheral line is mainly composed of a curved portion and is represented by a single quadratic curve,
  • the angle ( ⁇ 31 ) between the tangent line and the base line at all points on the curve is 90% or more with respect to the total length of the base line of the unit lens shape and is a part of the portion
  • the ratio (r 31 ) of the total length (r 31 ) projected to the base line of the lens cross-sectional shape of the part (R 31 ) is 20% or more including the curved line part (R 31 ) where 31 ⁇ 40 °
  • the present invention also includes a method for manufacturing the optical sheet, a light source device for a display device that requires the optical sheet and a prism sheet, and a display device that includes the light source device for the display device.
  • the luminance in the viewing angle direction in the region immediately above the line light source of the light source device and the luminance in the viewing angle direction in the intermediate region of the adjacent line light sources can be independently adjusted. It becomes possible. Therefore, in various apparatus settings (apparatus configuration, light source apparatus conditions, combinations with optical sheets other than the present invention), high brightness uniformity on the light exit surface side in the settings can be realized.
  • FIG. 7 is an explanatory diagram of a surface shape of a first unit lens in Examples 1 to 6.
  • FIG. 10 is an explanatory diagram of a surface shape of a first unit lens in Example 7.
  • FIG. 10 is an explanatory diagram of a surface shape of a first unit lens in Example 8.
  • FIG. 14 is an explanatory diagram of a surface shape of a first unit lens in Example 9.
  • FIG. 14 is an explanatory diagram of a first unit lens surface shape in Example 10.
  • FIG. 12 is an explanatory diagram of a surface shape of a first unit lens in Example 11. It is explanatory drawing of an example of the 1st unit lens surface shape in Examples 12 and 13.
  • FIG. FIG. 22 is an explanatory diagram of a lens group of the optical sheet of Example 14.
  • 10 is an explanatory diagram of a lens group of an optical sheet of Comparative Example 5.
  • FIG. 10 is an explanatory diagram of a lens group of an optical sheet of Comparative Example 5.
  • FIG. 42 is an explanatory diagram of a lens group of an optical sheet according to Example 27.
  • FIG. FIG. 22 is an explanatory diagram of an example of a unit lens cross-sectional shape 1 in Examples 28 to 33.
  • FIG. 22 is an explanatory diagram of an example of a unit lens cross-sectional shape 2 in Examples 28 to 35. It is explanatory drawing of an example of the unit lens cross-sectional shape 1 in Example 34,35.
  • FIG. 42 is an explanatory diagram of a lens group of an optical sheet according to Examples 28 to 33. It is explanatory drawing of arrangement
  • the first optical sheet refers to an optical sheet arranged first in the direction from the light source to the liquid crystal panel
  • the second and subsequent optical sheets are the second, third, and fourth, respectively.
  • the optical sheets in the order of arrangement see FIG. 1.
  • the optical sheet closest to the front panel corresponds to the fourth optical sheet denoted by reference numeral 6 in FIG. If these optical sheets can achieve the purpose of installation (for example, improvement in luminance) without causing any hindrance (for example, significant increase in thickness and cost), there is no upper limit on the number of sheets.
  • the optical sheet of the present invention is an optical sheet having a convex lens group formed on the surface in a linear bowl shape, all in a vertical cross-sectional shape with respect to the length direction of the lens group.
  • the outer peripheral line of the convex portion of the lens is composed of a curve and / or a straight line, and the tangent and / or the angle ( ⁇ ) between the straight line and the base line at all points on the curve is ⁇ ⁇ 40 °.
  • an element (X 1) includes a portion (X 2) the angle of the tangent line and / or the straight line and the baseline (theta) is 25 ° ⁇ ⁇ ⁇ 35 ° at all points on the curve
  • the total length (x 1total ) of the length (x 1 ) projected onto the base line of the lens group of the portion (X 1 ) is 25% or more and 60% of the total length (P total ) of the base line length of the lens group. less and, and, on the baseline of the lens group of the partial (X 2)
  • the length and shadow (x 2) total (x 2total) characterized in that the total length of the lens group of the base line is 60% or less 25% or more (P total).
  • the light from the light source can be sufficiently diffused into the intermediate portion of the cold cathode tube array, and the luminance in the viewing angle direction at the intermediate portion can be increased. Can be improved. Furthermore, in order to increase the luminance in the viewing angle direction, the luminance of the upper region of the cold cathode tube is also increased when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is superimposed on the optical sheet of the present invention. Can be secured sufficiently.
  • the straight line as used in the field of this invention means the straight line segment which connects the terminal ends
  • the curve in which the line segment which connects a terminal part has a very small curvature near a straight line is also contained.
  • the curve referred to in the present invention includes a curve that is different from a straight line but has a small curvature close to the straight line.
  • the minimum structural unit defined in the present invention is in the order of microns, but when observed in the order of microns, for example, when a vertical section of an optical sheet is observed with an electron microscope, the curved portion defined in the present invention is In the case of a curve with a small curvature that is difficult to determine as a curve in that order, the determination is performed as follows, for example.
  • the value of 100 ⁇ d / A exceeds 1 when the shortest distance d between the point on the curve farthest from the straight line and the straight line In this case, it is determined as a curve, and when the value of 100 ⁇ d / A is 1 or less, it is determined as a straight line.
  • the lowest part is the lowest point of the outer peripheral line of the convex part of the unit lens.
  • the base line is a straight line connecting the lowest part and the lowest part.
  • the top portion is the highest point from the base line in the outer peripheral line of the convex portion of the unit lens.
  • an angle ( ⁇ ) formed between a tangent line at all points on the curve and / or the straight line and a base line is ⁇ ⁇ 40 °.
  • Examples of the portion (X 1 ) include a curved portion (R 11 ) of the first unit lens, a curved portion (R 21 ) of the second unit lens, and a curved portion (R 31 ) of the unit lens having the shape 2 described later. Is applicable.
  • the length (x 1 ) for example, the total length (r 11 ) obtained by projecting the portion (X 1 ) of the first unit lens, which will be described later, onto the base line, and the portion of the second unit lens ( X 1) total length of the projected to the ground line (r 21), total of said portion (X 1) a length obtained by projecting the baseline of the unit lens having the shape 2 (r 31) corresponds.
  • an angle ( ⁇ ) formed between a tangent line at all points on the curve and / or the straight line and a base line is 25 ° ⁇ ⁇ ⁇ 35 °.
  • Examples of the portion (X 2 ) include a curved portion (R 12 ) of the first unit lens described later, a straight portion (R 22 ) of the second unit lens, a portion of the unit lens (R 32 ) having the shape 1, The unit lens portion (R 34 ) having the shape 2 is applicable.
  • the length (x 2 ) for example, the total length (r 12 ) obtained by projecting the portion (X 2 ) of the first unit lens, which will be described later, onto the base line
  • the length projected on the base line of the lens group is obtained for the part (X 1 ) and the part (X 2 ) of all the lenses of the convex lens group formed on the surface.
  • the total (x 1total ) and the total (x 2total ) include not only a first unit lens, a second unit lens, a unit lens having shape 1 and a unit lens having shape 2 which will be described later, but also other structures.
  • unit lenses having a lenticular shape eg, lenticular shape. That is, in the second embodiment to be described later, as shown in FIG. 2, the total of the second unit lens and the lenticular unit lens is obtained.
  • these surface shapes are set on the light exit surface side.
  • the surface shape configuration on the light incident surface side of the optical sheet of the present invention is not particularly limited and can be appropriately selected from flat surfaces, embossed surfaces, mat surfaces, surfaces having optical elements such as lenses, etc.
  • An embossed surface and a mat surface are preferably used from the viewpoints of preventing sticking, preventing sound noise, and exhibiting a light scattering effect.
  • the lens group includes a first unit lens (see FIG. 6).
  • the lens group includes a second unit lens (see FIGS. 7 to 10).
  • a convex portion outer peripheral line in a vertical cross-sectional shape with respect to the length direction of the unit lens is mainly composed of a curve, and tangent lines and base lines of all points on the curve are formed.
  • angle (theta 11) is the theta 11 ⁇ 40 ° curved section and (R 11), the angle between the tangent and the base line at all points on the curve (theta 12) is 25 ° ⁇ ⁇ 12 ⁇ 35 ° curved portion is comprises (R 12), wherein the curved portion (R 11) said unit said fraction of the total length of the base line of the lens total length of the projected the baseline configuration (r 11) is 25% or more 60 % And the ratio of the total length (r 12 ) of the curved portion (R 12 ) projected onto the base line of the unit lens shape to the total length of the base line is 25% or more and 60% or less. .
  • the ratio of the total length (r 11 ) projected onto the base line of the curved portion (R 11 ) to the total length of the base line is 25% or more and 60% or less, and is projected onto the base line of the curved portion (R 12 ).
  • the luminance of the upper region of the cold cathode tube is also increased when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is superimposed on the optical sheet of the present invention. Can be secured sufficiently. Therefore, by using the optical sheet of the first embodiment, the distance between the line light source and the optical sheet due to further thinning, the number of line light sources for reducing the energy consumption and cost of the liquid crystal display device It has become possible to eliminate uneven brightness even in liquid crystal display panels, where it has become increasingly difficult to eliminate uneven brightness, which is an increase in the interval between line light sources due to the reduction in the number of lines.
  • Curve part The curve part (R 11 ) is preferably a part of a quadratic curve from the viewpoints of design easiness, workability, and optical performance. Further, the curved portion (R 11 ) may be a combination of one or two or more quadratic curves, and may be arranged symmetrically on the right and left of the convex portion outer peripheral line or asymmetrically arranged.
  • the quadratic curve means an ellipse including a circle, a hyperbola, and a parabola.
  • the eccentricity is preferably 0.50 or more and 0.95 or less, more preferably 0.70 or more and 0.93 or less, and 0.80 or more and 0.8. 90 or less is more preferable.
  • the curved part (R 12 ) may be a part of a quadratic curve, like the curved part (R 11 ).
  • the curve portion (R 12 ) has a narrow tangent angle of 25 ° ⁇ ⁇ 12 ⁇ 35 ° ( ⁇ 12 ) between the tangent line and the base line at all points on the curve, and the base line. Since the ratio of the total projected length (r 12 ) to the total length of the base line needs to be 25% or more and 60% or less, it is not necessarily a part of the quadratic curve. It may be composed of any one or more curves that satisfy the following conditions.
  • be arranged symmetrically to the right and left of the convex portion outer peripheral line may be arranged asymmetrically.
  • the curve on the outer periphery of the convex portion in the vertical cross-sectional shape with respect to the length direction of the first unit lens is composed of two or more types of segments including the curved portion (R 11 ) and the curved portion (R 12 ).
  • the ratio of the total length (r 11 ) projected onto the base line of the curved portion (R 11 ) to the total length of the base line is 25% or more and 60% or less.
  • the ratio of the total (r 11 ) exceeds 60%, a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid.
  • the brightness of the tube upper area is lowered, causing new brightness unevenness.
  • the ratio of the total (r 11 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
  • the ratio of the total length (r 12 ) projected onto the base line of the curved portion (R 12 ) to the total length of the base line is 25% or more and 60% or less.
  • the ratio of the total (r 12 ) is less than 25%, in order to increase the luminance in the viewing angle direction, when a commonly used optical sheet such as a prism sheet or a diffusion sheet with a lens is superposed, a cold cathode The luminance of the tube upper area is lowered, and it becomes difficult to eliminate luminance unevenness.
  • the ratio of the total (r 12 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
  • curved portions may be directly connected to form a convex portion outer peripheral line, or an angle formed by a tangent and a base line at a straight line portion or a point on the curve.
  • ( ⁇ 13 ) may be connected via a curved portion (R 13 ) of 35 ° ⁇ 13 ⁇ 40 ° or ⁇ 13 ⁇ 25 °.
  • the ratio of the total length (r 13 ) projected onto the base line of these joints to the total base line length is preferably 40% or less. 20% or less is more preferable.
  • the connecting method of the curved portion (R 11 ) and the curved portion (R 12 ) may be symmetrical with respect to the outer peripheral line of the convex portion or may be asymmetrical with the left and right sides, and these connecting methods are adjusted. By doing so, it is possible to eliminate more uneven brightness.
  • the number of the curved portion (R 11 ) and the curved portion (R 12 ) is not particularly limited as long as the ratio of r 11 and r 12 is satisfied, but it is preferable that two exist each. Either of the setting positions of the curved portion (R 11 ) and the curved portion (R 12 ) may be close to the base portion. It is desirable from the viewpoint of moldability that the curved portion (R 11 ) is close to the base portion.
  • the curved portion (R 11 ) is close to the base portion, and the curved portion (R 11 ) and the curved portion (R 12 ) are symmetric with respect to the center line of the unit lens. .
  • the second unit lens is formed of a shape in which a convex outer peripheral line in a vertical cross-sectional shape with respect to the length direction of the unit lens is formed by connecting two or more curves and one or more straight lines, and At least two of the curves include a curved portion (R 21 ) in which an angle ( ⁇ 21 ) between a tangent line and a base line at all points on the curve is ⁇ 21 ⁇ 40 °, and the straight line (R 22 ) and the base The angle ( ⁇ 22 ) between the lines is 25 ° ⁇ ⁇ 22 ⁇ 35 °.
  • the straight line of the outer periphery of the convex portion in the vertical section, the number of curves, the position, ⁇ 21 of the curve, ⁇ 22 of the straight line, the luminance in the viewing angle direction in the region immediately above the cold cathode tube of the light source device, It is possible to independently adjust the luminance in the viewing angle direction in the intermediate region between adjacent cold-cathode tubes. Therefore, high brightness uniformity of the entire surface of the light source device can be realized in various device settings (light source device conditions, combinations with optical sheets other than the present invention).
  • the two or more curves and the one or more straight lines are, for example, a unit lens structure having a convex portion outer peripheral line having a cross section as shown in FIGS.
  • the number of straight lines is preferably two or more from the viewpoints of easy manufacture of a matrix used for lens shaping, ease of adjustment of optical performance as the entire optical sheet, and the like.
  • the curve constituting the convex outer peripheral line of the second unit lens is preferably a part of a quadratic curve such as an ellipse (including a circle) from the viewpoint of ease of design, workability, and optical performance. It may be a combination of one or more quadratic curves.
  • the eccentricity is preferably 0.50 or more and 0.95 or less. 70 or more and 0.93 or less are more preferable, and 0.80 or more and 0.90 or less are more preferable.
  • the angle ( ⁇ 21 ) between the tangent line and the base line at all points on the curve is ⁇ 21 ⁇ 40 °.
  • the ratio of the total length (r 21 ) projected on the base line of the curved portion (R 21 ) to the total length of the base line is preferably 25% or more and 60% or less. If the ratio of the total (r 21 ) is less than 25%, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is reduced, making it difficult to eliminate luminance unevenness. Become.
  • the ratio of the total (r 21 ) exceeds 60%, a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid.
  • the brightness of the tube upper area is lowered, causing new brightness unevenness.
  • the ratio of the total (r 21 ) is more preferably 27% or more and 58% or less, and further preferably 30% or more and 55% or less.
  • the curve on the outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the second unit lens has an angle ( ⁇ 23 ) between the tangent line and the base line at all points on the curve of 25 ° ⁇ ⁇ 23.
  • a curved portion (R 23 ) that is ⁇ 35 ° may be included.
  • Linear portion said linear angle (theta 22) of (R 22) and baseline must be within the range of less than 35 ° 25 ° or more. When there are two or more straight lines, at least one angle ( ⁇ 22 ) must satisfy this range. Further, as long as the angle ( ⁇ 22 ) is within this range, the angle of each straight line portion may be different.
  • a plane is formed as the entire unit lens and the entire optical sheet.
  • the viewing angle direction in the region immediately above the cold cathode tube of the light source device The luminance can be improved, and a decrease in luminance in the viewing angle direction in the region near the cold cathode tube of the light source device, which is generated by installing a normal lens sheet (prism sheet, lenticular sheet, etc.) can be eliminated.
  • the setting of the angle ( ⁇ 22 ) is adjusted so that it is directly above the cold cathode tube of the light source device.
  • the luminance in the viewing angle direction in the vicinity region can be improved.
  • the brightness in the viewing angle direction in the region immediately above the cold cathode tube of the light source device is improved by adjusting the setting of the angle ( ⁇ 22 ). It becomes possible to make it. If the angle ( ⁇ 22 ) is not within this range, it will be difficult to improve the luminance in the region immediately above the cold cathode tube of the light source device.
  • the shape of the entire outer periphery of the convex portion of the second unit lens is composed of a combination of the curve and the straight line.
  • the shape of the top of the outer peripheral line of the convex portion of the second unit lens may be a curved portion (see, for example, FIGS. 7 to 9), or a so-called prism shape (for example, only a straight portion) 10), or a shape in which a curved portion and a straight portion are combined.
  • the portion in contact with the base line may be either a straight line or a curved line.
  • FIG. 7 shows that the three curves of the convex portion including the top curve in the cross-sectional shape have a single elliptical shape.
  • FIG. 8 includes two curves and one straight line, and these two curves have a single elliptical shape.
  • FIG. 9 is an example in which the apex and the portion in contact with the base line have different elliptical shapes in the convex curve in the cross-sectional shape.
  • FIG. 10 is an example in which the top of the convex portion having a cross-sectional shape has a prism shape in which two straight lines are combined.
  • the distribution of the setting of the curve and the straight line is a ratio of the total length V of the convex portion outer peripheral line projected onto the lens-shaped base line and the total length W of the straight line projected onto the lens-shaped base line. It is prescribed.
  • the ratio (V: W) is preferably 15:85 or more and 85:15 or less.
  • the optimal curve and straight line ratio can be determined by the apex angle and pitch of the prism sheet.
  • the ratio (V: W) is preferably 20:80 or more and 80:20 or less, more preferably 30:70 or more and 80:20 or less, and further preferably 40:60 or more and 80:20 or less. 20 or less. If the ratio of the curve is smaller than this, sufficient light cannot be uniformly diffused to the intermediate region of the cold cathode tube array, and if it is larger than this, it becomes difficult to eliminate the dark line generated when the prism sheets are overlapped.
  • the angles ⁇ 11 and ⁇ 21 are 75 ° or more, incident light from the light source hardly reflects in the front direction at the curved portion due to reflection. Therefore, the total length projected on the base line of the portion where the angle ⁇ 11 , ⁇ 21 is 75 ° or more on the outer peripheral line of the convex portion of the unit lens vertical cross-sectional shape and the base line is 75 ° It is preferably 10% or less, more preferably 5% or less, relative to the total length of the line.
  • the setting of two or more ⁇ 11 max and ⁇ 21 max satisfying the conditions should be adjusted.
  • the combination of the optical sheet of the present invention and another optical sheet by adjusting the setting of two or more ⁇ 11 max and ⁇ 21 max satisfying the condition, in the intermediate region between adjacent cold cathode tubes. Since it becomes possible to improve the brightness
  • Ratio of height H to width P In the first or second unit lens, the length (P) of the base line and the height (H) from the base line to the lens apex in the vertical sectional shape with respect to the length direction of the unit lens
  • the ratio (H / P) is not particularly limited, but is preferably 0.25 or more and 0.75 or less, and more preferably 0.3 or more and 0.6 or less.
  • the ratio (H / P) when the ratio (H / P) is less than the above range, the composition ratio of the curved portion (R 11 ) to the curved portion (R 12 ) is reduced, and the middle of adjacent cold cathode tubes is reduced. It becomes difficult to sufficiently diffuse light into the region, and luminance in the viewing angle direction in this region cannot be improved.
  • the ratio (H / P) exceeds the above range, the ratio of the curved portion (R 12 ) to the curved portion (R 11 ) decreases, and an optical sheet such as a prism sheet or a diffusion sheet with a lens is overlaid.
  • an optical sheet such as a prism sheet or a diffusion sheet with a lens.
  • the luminance of the upper area of the cold cathode tube is insufficient, and it becomes difficult to eliminate the luminance unevenness.
  • the ratio (H / P) when the ratio (H / P) is less than the above range, the effect of the lens is reduced, and it is difficult to sufficiently diffuse light to an intermediate region between adjacent cold cathode tubes. Therefore, the luminance cannot be improved in the viewing angle direction in this region.
  • the ratio (H / P) exceeds the above range, the light is diffused to a portion beyond the intermediate region of the adjacent cold cathode fluorescent lamps, resulting in a decrease in luminance uniformity in the intermediate region.
  • the luminance uniformity in the viewing angle direction in this region is reduced.
  • the length (P) and height (H) of the unit lens may be set as appropriate according to the desired characteristics. Usually, the length (P) is 10 ⁇ m or more and 300 ⁇ m or less, and the height (H). Is 2.5 ⁇ m or more and 225 ⁇ m or less.
  • the first or second unit lens structure has an optimum shape in order to achieve high brightness uniformity. Therefore, usually other unit lens structures may be included. In order to exhibit preferable performance as the entire optical sheet, it is preferable that 50% by area or more of the entire light exit surface of the optical sheet is configured by the first unit lens and / or the second unit lens, and the structure by 60% by area or more. Is more preferable, 70% by area or more is more preferable, and 90% by area or more is more preferable. Examples of the other lens structure include a lenticular shape and a prism shape. In the unit lens structure configuration of these optical sheets, the first or second unit lens structure breakdown may be a combination configuration of the same or a combination configuration of a plurality of types of structures. In addition, it is a preferable aspect that the lens group includes only the first or second unit lens.
  • the lens group includes a unit lens (see FIG. 12) and a shape 2 having the following shape 1 as a convex portion outer peripheral line having a vertical cross-sectional shape with respect to the length direction. It has a unit lens (see FIG. 13).
  • the surface shape of the entire lens shaping surface of the optical sheet is configured by arranging at least two different types of unit lenses substantially in parallel.
  • the arrangement of the two different types of unit lenses may be arranged randomly without regularity, or may be arranged with a certain regularity.
  • the shape 1 includes a portion (R 32 ) where an angle ( ⁇ 32 ) between a tangent or straight line and a base line at all points on the curve is 25 ° ⁇ ⁇ 32 ⁇ 35 °.
  • the ratio of the total length (r 32 ) projected onto 32 baselines to the total baseline is 90% or more.
  • a cold cathode is formed when an optical sheet such as a prism sheet or a diffusion sheet with a lens generally used for increasing the luminance in the viewing angle direction is overlaid.
  • the luminance of the tube upper area is lowered, and it becomes difficult to eliminate luminance unevenness.
  • the ratio of the total (r 32 ) is more preferably 95% or more, and further preferably 100%.
  • the portion (R 32 ) occupying 90% or more of the shape 1 is composed of a straight line or a curve, and may be a combination of a plurality of straight lines and curves.
  • a so-called prism shape composed of two straight lines is one of the preferred embodiments of the present invention.
  • the curve is preferably a part of a quadratic curve, more preferably a part of a hyperbola from the viewpoints of design easiness, workability, and optical performance.
  • the shape 1 may be a left-right asymmetric shape, but is preferably left-right symmetric in order to reduce the luminance unevenness difference due to the viewing angle.
  • the shape 2 is a total of the lengths (r) projected on the base line of the unit lens shape of a portion (R 33 ) whose outer peripheral line is mainly composed of a curved portion and represented by a single quadratic curve. 33 ) is 90% or more with respect to the total length of the base line of the unit lens shape, and, as a part of the portion (R 33 ), an angle ( ⁇ between the tangent line and the base line at all points on the curve. 31), the curved portion is theta 31 ⁇ 40 ° comprises a (R 31), relative to baseline length of said portion (the lens section total length of the projected the baseline of the shape of the R 31) (r 31) The ratio is 20% or more.
  • the shape 2 has a portion (R 33 ) represented by a single quadratic curve, and the quadratic curve is preferably an ellipse or a part of a hyperbola.
  • the eccentricity is preferably 0.50 or more and 0.95 or less, more preferably 0.70 or more and 0.93 or less, and 0.80 or more and 0.90 or less. Is more preferable.
  • the shape 2 includes a curved portion (R 31 ) where the angle ( ⁇ 31 ) between the tangent line and the base line at all points on the curve is ⁇ 31 ⁇ 40 °.
  • the ratio of the total length (r 31 ) projected onto the baseline of (R 31 ) to the total length of the baseline is 20% or more.
  • the ratio of the total (r 31 ) is less than 20%, the light diffusion to the intermediate portion of the cold cathode tube array is reduced, and the luminance in the viewing angle direction at the intermediate portion is reduced, making it difficult to eliminate luminance unevenness.
  • the shape 2 may be an asymmetric shape, but is preferably left-right symmetric in order to reduce the luminance unevenness difference depending on the viewing angle.
  • the angle ( ⁇ 34 ) between the tangent line and the base line at all points on the curve is usually 25 ° ⁇ ⁇ 34 ⁇ 35 ° as a part of the portion (R 33 ). It also has a portion (R 34 ).
  • Shape 1 and shape 2 as the vertical cross-sectional shape with respect to the length direction of the unit lens in the optical sheet of the third embodiment are each a single shape as long as the above conditions are satisfied. There is no need, and the shape 1 and the shape 2 may include a plurality of types that satisfy the above-described conditions.
  • the area ratio of the unit lens having the shape 1 and the unit lens having the shape 2 is the sum of the respective projection areas on the entire light exit surface. 2) is preferably arranged to be 0.05 or more and 2.0 or less. In order to increase the luminance in the viewing angle direction when the area ratio is less than 0.05, when an optical sheet such as a commonly used prism sheet or a diffusion sheet with a lens is overlapped, Luminance decreases, and it may be difficult to eliminate luminance unevenness.
  • the area ratio is more preferably 0.1 or more and 1.5 or less, further preferably 0.15 or more and 1.0 or less, and most preferably 0.2 or more and 0.75 or less.
  • the lenses belonging to the shape 1 and the shape 2 are successively adjacent to each other while satisfying the above-described area ratio, and preferably 20 or less. More preferably.
  • the uniformity of the optical performance of the entire optical sheet is impaired, and the luminance leveling may be insufficient.
  • the layers are arranged substantially uniformly as a whole while satisfying the area ratio (shape 1 / shape 2). From the viewpoint of creating a master mold, it is most preferable to repeat the same arrangement pattern because it is easy to produce and the uniformity of the entire optical sheet is easy to design.
  • the length (P) of the base line of the outer peripheral line of the convex portion in the vertical cross-sectional shape with respect to the length direction of the unit lens is the length (L1) of the base line of the unit lens having the shape 1
  • the length (L2) of the base line of the unit lens having the shape 2 is preferably 30 ⁇ m or more and 300 ⁇ m or less, more preferably 40 ⁇ m or more and 200 ⁇ m or less, and further preferably 50 ⁇ m or more and 150 ⁇ m or less.
  • the height (H) from the base line of the convex portion outer peripheral line to the lens apex in the vertical cross-sectional shape with respect to the length direction of the unit lens has the height (H1) of the unit lens having the shape 1 and the shape 2.
  • the height (H2) of the unit lens is preferably 15 ⁇ m or more and 100 ⁇ m or less, more preferably 20 ⁇ m or more and 85 ⁇ m or more, and more preferably 25 ⁇ m or more and 65 ⁇ m or less.
  • the ratio (H / P) between the height (H) and the length (P) is not particularly limited, but as a unit lens having the shape 1, the ratio (H1 / L1) is 0.20 or more and 0.40. Or less, more preferably 0.22 or more and 0.35 or less. On the other hand, as a unit lens having the shape 2, the ratio (H2 / L2) is preferably 0.25 or more and 0.75 or less, and more preferably 0.30 or more and 0.65 or less.
  • the ratio (H / P) is less than the above range, the light diffusing effect of the lens becomes small, and the luminance uniformity may be lowered.
  • the ratio (H / P) exceeds the above range, the light diffused by the unit lens may be incident on the adjacent unit lens again and may not be emitted toward the front panel, which may reduce the luminance. There is.
  • the unit lens having the shape 1 and the unit lens having the shape 2 are optimally shaped and combined to achieve high brightness uniformity. Therefore, usually other unit lens structures may be included. In order to exhibit preferable performance as the entire optical sheet, it is preferable that 80% by area or more of the entire light exit surface of the optical sheet is constituted by the unit lens having the shape 1 and the unit lens having the shape 2; A structure of area% or more is more preferable, and a structure of 95 area% or more is more preferable.
  • the other unit lens structures may be the same combination or a plurality of combination structures.
  • the distance between the apexes of the convex portion outer peripheral lines of adjacent unit lenses is preferably 300 ⁇ m or less.
  • the luminance uniformity in the viewing angle direction is lowered, or a moire pattern is likely to occur depending on the combination with the optical sheet to be superimposed.
  • the arrangement of the lens groups arranged in the shape of the straight saddles only needs to be the arrangement ratio of the entire optical sheet.
  • the first or second unit lens, or the unit lens having the shape 1 and the unit lens having the shape 2 may be arranged at the above intervals, and other unit lenses (for example, a lenticular shape or a prism shape) may be arranged. It may be next door.
  • other unit lenses for example, a lenticular shape or a prism shape
  • the configuration of the connecting portion between adjacent unit lenses is not particularly limited as long as the target optical performance is not affected.
  • the lowest part of the outer peripheral line of the convex part in the vertical cross section with respect to the length direction of the unit lens is the base line. It is preferable that the unit lenses are aligned, that is, the unit lenses are arranged without gaps.
  • a gap may be provided between each unit lens as long as it does not affect the optical performance of the entire optical sheet.
  • a slight gap is given so as to facilitate release after the lens shape transfer.
  • any shape such as a straight line, a concave curve, or a V-shape can be used as long as the optical performance is not affected.
  • the invention is synonymous with no gap.
  • thermoplastic resin constituting the optical sheet of the present invention is not particularly limited as long as it is transparent and has an appropriate strength as a main component of the optical sheet.
  • thermoplastic resin for example, polycarbonate resin; acrylic resin such as polymethyl methacrylate; styrene resin such as polystyrene, polyvinyl toluene, poly (p-methylstyrene); MS resin (copolymer of methyl methacrylate and styrene); norbornene resin Polyolefin resin; Polyarylate resin; Polyethersulfone resin Among these, two or more kinds of mixed resins can be used.
  • a polycarbonate resin, a styrene resin, or a norbornene resin is preferably used.
  • polycarbonate resin is particularly preferable as a resin for an optical sheet because it is excellent in transparency, heat resistance, and workability and has a good balance.
  • the thermoplastic resin may contain an ultraviolet absorber, a fluorescent whitening agent, a flame retardant, and the like as necessary.
  • the optical sheet of the present invention may be composed only of a transparent resin, but in order to adjust light diffusibility, a light diffusion layer made of particles having light diffusibility may be provided.
  • the light diffusing layer may be uniformly or randomly dispersed in the entire optical sheet, only the lens portion, the entire portion other than the lens portion, only the light exit surface layer, only the light entrance surface layer, or the intermediate layer.
  • light diffusing particles having a refractive index of 0.01 or more different from that of a transparent resin are dispersed in a thermoplastic resin. It has adjustment effects such as direction and diffusion ratio, and it is possible to further increase the brightness uniformity in the viewing angle direction.
  • the support pin image can be erased even when the number of sheets used is reduced.
  • Light diffusing agent examples include (meth) acrylic resins, styrene resins, polyurethane resins, polyester resins, silicone resins, fluororesins, and copolymers thereof. Glass; clay compounds such as smectite and kaolinite; inorganic oxides such as silica and alumina; and the like. Of these materials, (meth) acrylic resins, silicone resins, and silica are particularly suitable.
  • the light diffusing agent may be a single material, a mixture of single materials, a mixed material, or a mixture of mixed materials of these exemplified materials.
  • (meth) acryl means acryl and / or methacryl.
  • the average particle size of the light diffusing particles is preferably from 0.1 ⁇ m to 50 ⁇ m, more preferably from 0.3 ⁇ m to 10 ⁇ m, and even more preferably from 0.5 ⁇ m to 5 ⁇ m.
  • the average particle diameter of the light diffusing particles is a volume-based median diameter measured by a particle size distribution measuring device (Coulter counter).
  • the ratio between the thermoplastic resin and the light diffusing particles may be adjusted as appropriate. For example, if the light diffusing particles are added in an amount of 0.01 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin. Good. When the amount of the light diffusing particles is less than 0.01 parts by mass, the luminance uniformity adjustment by the light diffusing agent cannot be sufficiently performed. On the other hand, if the light diffusing particles exceed 10 parts by mass, the transparency of the light diffusing layer may be lowered, and the brightness of the entire optical sheet may be lowered.
  • low crosslink density organic fine particles capable of exhibiting anisotropic light diffusibility during the molding of the optical sheet are preferably used.
  • Raw material monomers for the low crosslink density organic fine particles include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n- Butyl (meth) acrylate, iso-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxy (Meth) acrylates such as propyl (meth) acrylate;
  • Low crosslinking density organic fine particle crosslinking agents include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and trimethylolpropane tri (meth).
  • Polyfunctional (meth) acrylates such as acrylate and bishydroxyethyl bisphenol A di (meth) acrylate; radical polymerizable crosslinking agents such as divinyloxyethoxy (meth) acrylate, diallyl phthalate, allyl (meth) acrylate, and divinylbenzene; bisphenol Polyfunctional epoxy compounds such as A diglycidyl ether, diethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether; tolylene diisocyanate, Siri diisocyanate, polyfunctional isocyanate compounds such as isophorone diisocyanate; N- methylol melamine, polyfunctional methylol compounds such as N- methylol benzoguanamine; one, or may be used in combination of two or more thereof.
  • radical polymerizable crosslinking agents such as divinyloxyethoxy (meth) acrylate, diallyl phthalate, allyl (meth)
  • the crosslink density of the low crosslink density organic fine particles for achieving anisotropic light diffusion performance is preferably 0.001% or more and 0.12% or less.
  • Such organic fine particles having a low cross-linking density are spherical or substantially spherical at the raw material stage, but are formed into an ellipsoidal shape or a rod shape at a predetermined position (layer, etc.) of the optical sheet due to heat, shearing force, etc. received during molding of the optical sheet. When this shape is changed, anisotropic diffusivity is expressed.
  • a crosslinking density is a numerical value calculated
  • Fn (c) number of functional groups of the crosslinking agent used for producing the radical polymer-based crosslinked fine particles Mw (c): molecular weight of the crosslinking agent used for producing the radical polymer-based crosslinked fine particles W (c): crosslinking agent used for producing the radical polymer-based crosslinked fine particles Mass blending ratio (%) W (m): Mass blending ratio (%) of monomer used for production of radical polymerized crosslinked fine particles
  • Antioxidant An antioxidant may be further blended in at least one of the organic fine particles including the low crosslink density organic fine particles of the present invention or the thermoplastic resin. Since the antioxidant can suppress coloring of the thermoplastic resin and organic fine particles due to oxidation and deterioration during thermoforming, the brightness of the backlight device to which the optical sheet of the present invention is applied can be more reliably exhibited. .
  • antioxidant a conventionally known antioxidant can be used.
  • octadecyl-3- (3,5-di-t-butyl-1-hydroxyphenyl) propionate etc.
  • Hindered phenolic antioxidants tris (2,4-di-t-butylphenyl) phosphite, tris [2-[[2,4,8,10-tetra-t-butyldibenzo [d, f] [ Phosphorous antioxidants such as 1,3,2] dioxaphosphine-6-yl] oxy] ethyl] amine; thiodiethylenebis [3- (3,5-di-t -Butyl-4-hydroxyphenyl) propionate] and the like having no aromatic ring, pentaerythrityltetrakis (3-laurylthiopropionate) Sulfur-based antioxidants such as; lactone-based antioxidants such as the reaction product of 3-hydroxy-5,7-di-t-butyl-furan-2-one and o-xylene; Hydroxylamine antioxidants such as oxidation products of alkylamines; 3,4-dihydro-2,5,7,8-tetra
  • the amount of the antioxidant used may be adjusted as appropriate, but it is usually sufficient to add about 0.005 mass% or more and 0.3 mass% or less with respect to the thermoplastic resin. That is, an antioxidant may be added in an amount of about 0.005 parts by mass to about 0.3 parts by mass with respect to 100 parts by mass of the thermoplastic resin.
  • the thickness of the optical sheet of the present invention can be adjusted as appropriate and is not particularly limited, but can usually be about 0.3 mm or more and 10 mm or less. If the thickness of the optical sheet is less than 0.3 mm, the light diffusing action may not be sufficiently exhibited, or the rigidity may be insufficient to maintain the shape stability. On the other hand, if the thickness of the optical sheet exceeds 10 mm, the entire apparatus to which the optical sheet of the present invention is applied may not be made compact. More preferably, the thickness of the optical sheet is 0.5 mm or more and 5 mm or less. The thickness of the optical sheet is the sum of the thickness of the base and the unit lens height (see FIGS. 4, 5, and 11).
  • the optical sheet of the present invention can be manufactured by using a matrix facing a predetermined surface shape.
  • the shape of the matrix is a shape for the lens group of the obtained optical sheet to realize the predetermined surface shape defined in the present invention, that is, the convex portion of these surface shapes is concave and the concave portion is convex. Any structure can be used.
  • the matrix having these structures is referred to as a “facing matrix for forming the surface shape” (see FIGS. 14 and 15).
  • the optical sheet of the present invention can be manufactured by a manufacturing process having the matrix. Specifically, it can be obtained by known extrusion molding or injection molding using a transparent thermoplastic resin or a mixture of transparent thermoplastic resin and fine particles having light diffusibility.
  • a laminated body is used to adjust optical performance and other physical properties (for example, when a light diffusing layer is installed only on a specific layer such as a light incident side or a lens side, or UV light for improving the light resistance of an optical sheet)
  • the extrusion method is particularly preferable from the viewpoint of productivity. Further, it is particularly preferable to use the method described in Japanese Patent Application No. 2008-249254 when shaping a lens shape having a narrow pitch.
  • a molded product according to the design of the present invention can be manufactured can be confirmed by obtaining x 1 and x 2 from the molded product. Specifically, a vertical cross-sectional shape with respect to the length direction of the unit lens is photographed with an electron microscope or the like, and an appropriate curve (a plurality of combinations may be used) with respect to the curved portion in the outer peripheral line of the convex portion. ) And the angle between the tangent line and the base line is determined from the range of the outer peripheral line, and for the straight line portion, the range of the outer peripheral line where the angle at which the straight line is the base line is the predetermined angle. Ask from.
  • the optical sheet of the present invention is preferably used as the first optical sheet in order to efficiently use its high optical performance adjustment capability in other optical sheets and apparatus settings.
  • the effect of improving the luminance in the viewing angle direction in the intermediate region of the adjacent cold cathode tubes of the light source device and the luminance in the viewing angle direction in the region immediately above the cold cathode tube are improved.
  • the effect can be utilized to the maximum.
  • the other optical sheet can be a prism sheet, a diffusion sheet, a microlens sheet, etc., and the combination is also selected according to the conditions of the light source device.
  • a diffusion sheet as the optical sheet closest to the front panel.
  • the use of at least one prism sheet for the second and subsequent optical sheets eliminates dark lines generated near the cold cathode tube and achieves high brightness and brightness uniformity on the light exit surface immediately before the front panel. It becomes possible.
  • the optical sheet of the present invention exhibits excellent light diffusion performance when used in combination with a prism sheet, the pattern of the line light source can be erased even if the number of optical sheets used is reduced to three. Become. Thus, it has been found that the image of the support pin becomes noticeable only for the first time by reducing the number of sheets used to 3 using the optical sheet of the present invention.
  • the optical sheet of the present invention has a light diffusing layer, in the direct type light source device, the performance of erasing the image of the support pins that support the optical sheet is also improved. Accordingly, when the optical sheet of the present invention has a light diffusing layer, it is also a preferable aspect to use only three sheets of the optical sheet, the prism sheet and the light diffusing sheet of the present invention.
  • the optical sheet manufactured according to the present invention can diffuse light in a desired direction, and as a result, can maintain the uniformity of the light, thereby reducing the manufacturing cost of the liquid crystal display device, which is in increasing demand. It is extremely useful industrially as a material that can exhibit high brightness. Therefore, the manufacturing cost can be reduced by applying the optical sheet of the present invention and the direct light source device having the optical sheet to a liquid crystal display device or the like.
  • a white reflective plate is provided on the inner surface of a plastic case having an inner width of 690 mm, a depth of 390 mm, and a depth of 10 mm, and a cold cathode tube having a diameter of 3 mm at a position 3.5 mm away from the bottom of the reflector.
  • a direct type light source device in which 19 pieces were arranged in parallel at intervals of 20.5 mm was used.
  • the optical sheets of the present invention having various shapes were arranged such that the lens processing surface was on top and the longitudinal direction of the lens was parallel to the longitudinal direction of the cold cathode tube.
  • a commercially available light diffusing sheet (CH273 manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd.), prism sheet (BEF II 90/50 manufactured by Sumitomo 3M: apex angle 90 degrees, pitch 50 ⁇ m), microlens sheet ( ML24M manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd .: an optical sheet in which hemispherical convex lens groups are finely arranged on one surface) was placed according to the combinations shown in Table 4. In each combination, luminance unevenness was visually observed from a position 400 mm away from the center of the direct light source device in the vertical direction. The brightness unevenness is evaluated in 10 stages, and the larger the value, the less the brightness unevenness, indicating that the lamp image of the cold cathode tube is not noticeable. The evaluation results are shown in Tables 1 to 3.
  • the length (x 1 ), length (x 2 ) of each unit lens constituting the lens group, and the total (x 1total ) and total (x 2total ) of the entire lens group are summarized in Table 5.
  • the total (x 1total ) is 25% to 60% of the total length (P total ) of the baseline of the lens group, and the total (x 2Total ) is the length of the baseline of the lens group
  • Examples 1 to 35 that are 25% to 60% of the total (P total ) are used, the luminance unevenness is small in any combination shown in Table 4.
  • a white reflective plate is provided on the inner surface of a plastic case with an inner dimension width of 690 mm, a depth of 390 mm, and a depth of 25 mm, and a cold 3 mm diameter is placed at a position 5 mm away from the bottom of the reflector.
  • a direct type light source device in which eight cathode tubes were arranged in parallel at intervals of 45 mm and support pins were arranged as shown in FIG. 30 was used.
  • the optical sheets of the present invention having various shapes were arranged such that the lens processing surface was on top and the longitudinal direction of the lens was parallel to the longitudinal direction of the cold cathode tube.
  • a prism sheet (BEF II 90/50: vertical angle 90 degrees, pitch 50 ⁇ m, manufactured by Sumitomo 3M) is placed on this optical sheet, and a microlens sheet (manufactured by Hiroshige Kogyo (Suzhou) Co., Ltd.) ML24M: one side
  • An optical sheet in which hemispherical convex lens groups are finely arranged is placed on the surface.
  • the support pin image and the luminance unevenness were visually observed from a position 400 mm away from the center of the direct light source device in the vertical direction.
  • the support pin image when it was confirmed visually, it was judged as “bad”, when it was confirmed partially, “good”, and when it could not be confirmed at all, “excellent”.
  • the brightness unevenness is evaluated in 10 stages, and the larger the value, the less the brightness unevenness, indicating that the lamp image of the cold cathode tube is not noticeable. The evaluation results are shown in Table 6.
  • Example 13 is an optical sheet in which the total (x 1Total ) and the total (x 2Total ) are within the specified range of the present invention, and a light diffusion layer is provided.
  • the support pin image can be erased by the group of three optical sheets, and luminance unevenness is small.
  • the first optical sheet capable of improving the luminance ratio at the intermediate point between the line light sources arranged in parallel with each other and / or directly above the cold cathode tube, and obtaining a uniform luminance distribution;
  • a direct light source device and a liquid crystal display device can be provided, which is extremely useful in industry.

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  • Health & Medical Sciences (AREA)
  • Ophthalmology & Optometry (AREA)
  • Mechanical Engineering (AREA)
  • Planar Illumination Modules (AREA)
  • Liquid Crystal (AREA)

Abstract

L'invention concerne une feuille optique pour écrans à cristaux liquides permettant l'amélioration des rapports de luminance aux points centraux entre les sources lumineuses linéaires situées l'une à côté de l'autre et les positions directement au-dessus des sources lumineuses linéaires et une répartition de luminance uniforme. L'invention concerne également un procédé de fabrication de la feuille optique, une source lumineuse située directement en dessous et un dispositif d'affichage à cristaux liquides. La feuille optique comprenant des lentilles convexes réalisées selon des formes de crêtes linéaires sur sa surface est caractérisée en ce que la ligne externe des crêtes de l'ensemble des lentilles présentées dans la section transversale, vues perpendiculairement à leurs directions longitudinales est composée de courbes et/ou de lignes, et comprend à un rapport prédéterminé des parties (X1) satisfaisant la condition selon laquelle les angles (θ) formés par les tangentes à l'ensemble les points des courbes et/ou par les lignes et lignes de base sont de θ ≥ 40° et des parties (X2) où les angles (θ) sont de 25°≤ θ ≤35°.
PCT/JP2009/068522 2008-10-28 2009-10-28 Feuille optique, procédé de fabrication de feuille optique, source lumineuse incluant la feuille optique et dispositif d'affichage WO2010050522A1 (fr)

Priority Applications (1)

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CN2009801432461A CN102197324A (zh) 2008-10-28 2009-10-28 光学片及该光学片的制备方法以及包括该光学片的光源装置、显示装置

Applications Claiming Priority (12)

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JP2008-277517 2008-10-28
JP2008277517 2008-10-28
JP2009-017368 2009-01-28
JP2009017368 2009-01-28
JP2009-024323 2009-02-04
JP2009024323 2009-02-04
JP2009052683 2009-03-05
JP2009-052683 2009-03-05
JP2009-075836 2009-03-26
JP2009075836 2009-03-26
JP2009100057 2009-04-16
JP2009-100057 2009-04-16

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WO2010050522A1 true WO2010050522A1 (fr) 2010-05-06

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KR (1) KR20110082134A (fr)
CN (1) CN102197324A (fr)
WO (1) WO2010050522A1 (fr)

Cited By (1)

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JP2011248227A (ja) * 2010-05-28 2011-12-08 Toppan Printing Co Ltd 隠蔽構造体を備えた照明ユニット、照明装置、表示装置

Families Citing this family (3)

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Publication number Priority date Publication date Assignee Title
KR101208403B1 (ko) * 2011-12-27 2012-12-05 동우 화인켐 주식회사 도광판 및 이를 포함하는 백라이트 유닛
JP6886992B2 (ja) * 2018-03-30 2021-06-16 恵和株式会社 光拡散板積層体、バックライトユニット、及び液晶表示装置
CN108931836B (zh) * 2018-08-17 2020-07-03 京东方科技集团股份有限公司 导光板及确定方法、背光源、显示装置、可读存储介质

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JPH0843634A (ja) * 1994-07-29 1996-02-16 Dainippon Printing Co Ltd フィルムレンズ、面光源及び透過型表示体
JPH09304606A (ja) * 1996-05-15 1997-11-28 Mitsubishi Plastics Ind Ltd 光拡散性プリズムシート
JP2007003567A (ja) * 2005-06-21 2007-01-11 Dainippon Printing Co Ltd 光制御シート、及び、面光源装置
JP2007178628A (ja) * 2005-12-27 2007-07-12 Fujifilm Corp プリズムシート
JP2008146886A (ja) * 2006-12-06 2008-06-26 Sony Corp 面発光装置及びこれを備えた表示装置

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KR101107828B1 (ko) * 2003-03-03 2012-01-31 미츠비시 레이온 가부시키가이샤 광 편향 소자 및 광원 장치

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Publication number Priority date Publication date Assignee Title
JPH0843634A (ja) * 1994-07-29 1996-02-16 Dainippon Printing Co Ltd フィルムレンズ、面光源及び透過型表示体
JPH09304606A (ja) * 1996-05-15 1997-11-28 Mitsubishi Plastics Ind Ltd 光拡散性プリズムシート
JP2007003567A (ja) * 2005-06-21 2007-01-11 Dainippon Printing Co Ltd 光制御シート、及び、面光源装置
JP2007178628A (ja) * 2005-12-27 2007-07-12 Fujifilm Corp プリズムシート
JP2008146886A (ja) * 2006-12-06 2008-06-26 Sony Corp 面発光装置及びこれを備えた表示装置

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2011248227A (ja) * 2010-05-28 2011-12-08 Toppan Printing Co Ltd 隠蔽構造体を備えた照明ユニット、照明装置、表示装置

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CN102197324A (zh) 2011-09-21
KR20110082134A (ko) 2011-07-18

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