WO2006054654A1 - Light guide plate - Google Patents

Light guide plate Download PDF

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Publication number
WO2006054654A1
WO2006054654A1 PCT/JP2005/021139 JP2005021139W WO2006054654A1 WO 2006054654 A1 WO2006054654 A1 WO 2006054654A1 JP 2005021139 W JP2005021139 W JP 2005021139W WO 2006054654 A1 WO2006054654 A1 WO 2006054654A1
Authority
WO
WIPO (PCT)
Prior art keywords
guide plate
light guide
light
plate according
angle
Prior art date
Application number
PCT/JP2005/021139
Other languages
French (fr)
Japanese (ja)
Inventor
Kazuhiro Makishima
Teruo Teshima
Yoshiyasu Ishikawa
Masao Inose
Original Assignee
Hitachi Chemical Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Chemical Co., Ltd. filed Critical Hitachi Chemical Co., Ltd.
Publication of WO2006054654A1 publication Critical patent/WO2006054654A1/en

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Classifications

    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL 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
    • G02F1/00Devices 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
    • G02F1/01Devices 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 
    • G02F1/13Devices 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133524Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011Light 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
    • G02B6/0033Means for improving the coupling-out of light from the light guide
    • G02B6/0035Means 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
    • G02B6/00362-D arrangement of prisms, protrusions, indentations or roughened surfaces
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011Light 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
    • G02B6/0033Means for improving the coupling-out of light from the light guide
    • G02B6/0056Means for improving the coupling-out of light from the light guide for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011Light 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
    • G02B6/0033Means for improving the coupling-out of light from the light guide
    • G02B6/0058Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide
    • G02B6/0061Means for improving the coupling-out of light from the light guide varying in density, size, shape or depth along the light guide to provide homogeneous light output intensity
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL 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
    • G02F1/00Devices 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
    • G02F1/01Devices 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 
    • G02F1/13Devices 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
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133504Diffusing, scattering, diffracting elements

Definitions

  • the present invention relates to a light guide plate used in a backlight device that irradiates a liquid crystal display element or the like from the back and a backlight device including a powerful light guide plate.
  • a light guide plate that guides light emitted from a light source to a liquid crystal display device
  • a knock light device that includes the light guide plate and illuminates the liquid crystal display device from the back side.
  • FIG. 1 is a schematic diagram showing an external appearance of the liquid crystal display device 10.
  • 1 is a light guide plate
  • 2 is a light source
  • 3 is an exit surface
  • 4 is a reflection surface
  • 5 is an entrance surface
  • 6 is a deflection pattern element
  • 7 is a liquid crystal
  • 8 is a reflector
  • 9 is an optical sheet
  • 11 is a holder.
  • 12 are rays
  • 13 is the observer's viewpoint.
  • the backlight device 14 is a state where the liquid crystal panel is removed from the liquid crystal display device 10.
  • the light guide plate 1 also has a transparent material force such as PMMA or polycarbonate, and has a substantially plate-like flat shape.
  • One side surface is defined as an incident surface 5, and a deflection pattern is formed on the reflecting surface 4 by a plurality of deflection pattern elements 6 in order to reflect or deflect the light incident from the incident surface 5 toward the exit surface 3.
  • the light guide plate 1 is disposed below the liquid crystal panel 7 and is disposed such that the light exit surface 3 of the light guide plate 1 and the lower surface of the liquid crystal panel 7 face each other.
  • the light beam 12 emitted from the light source 2 enters the light guide plate 1 from the incident surface 5, travels inside the light guide plate, and rises in the direction of the output surface 3 by the deflection pattern element 6 formed on the reflection surface 4.
  • the light exits from the exit surface 3.
  • the light guide plate 1 that emits light incident from the incident surface 5 on the side surface from the output surface 3 on the main surface is referred to as a side edge method, and is widely used in mobile phones and the like (for example, Japanese Patent No. 3151830). Issue).
  • a hologram obtained by exposing a photosensitive film through a rectangular opening having a diffuser to form a large number of speckles at random (for example, US Pat. No. 5,365). No. 354 and U.S. Pat.No. 5,534,386. See).
  • the speckle has a substantially elliptical shape, and the major and minor axes of the ellipse have a relationship of Fourier transform with the short and long sides of the rectangular opening.
  • the laser light is scattered by each speckle and reproduces the rectangular opening used for the exposure.
  • incident light can be diffused anisotropically.
  • the deflection pattern element is generally a dodd pattern 15 as shown in FIG. 2 (a).
  • the deflection pattern element is an independent almost circular pattern, the light reflected by the deflection pattern element is not emitted in a certain direction as shown in Fig. 2 (b). There was a problem that it was difficult to increase
  • a light guide plate provided with a substantially V-shaped deflection pattern element as shown in FIG. 3 (a) has become mainstream.
  • This V-shaped grooved deflection element is generally provided so that the direction of the V-shaped groove is parallel to the incident surface as shown in the top view of FIG.
  • FIG. 5 (b) is a side view of FIG. 5 (a) viewed from the direction of the light source 2.
  • FIG. 5 (b) is a side view of FIG. 5 (a) viewed from the direction of the light source 2.
  • FIG. 5 (b) Light from the light source 2 enters the light guide plate 1 from the incident surface 5.
  • the reflection groove is a straight line as in the conventional light guide plate, among the light beams emitted from the light source 2, the light beam 12a becomes a light beam locus deflected in the front direction by the prism film 10 disposed on the upper surface.
  • the light beam 12b (oblique light) is largely deflected by the linear reflecting surface, and the ray trajectory force that can be deflected in the front direction by the prism film 10 is also released, so that a portion with a small amount of light emission is generated. Was observed in the dark.
  • the present invention has been proposed in view of the above-described circumstances, and brightness brightness / darkness in the vicinity of an incident surface is proposed. It is an object of the present invention to provide a backlight device including a light guide plate that prevents the occurrence of light and a powerful light guide plate.
  • both the light rays 12a and 12b can be easily guided in the front direction by the deflection of the prism film disposed on the upper surface. It is possible to prevent brightness contrast in the vicinity of the incident surface, which is a difficult point.
  • An embodiment of the present invention is a plate-shaped light guide plate having an incident surface on a side surface and an output surface on an upper surface or a lower surface, and a plurality of light guide plates on the output surface or the surface facing the output surface.
  • a deflection pattern element is arranged, and the deflection pattern element has a quadrangular pyramid shape integrally formed on the light guide plate with four surface forces other than the bottom surface of the quadrangular pyramid.
  • the area of each of the first surface and the second surface is 20 times or more of the area of each of the adjacent third surface and the fourth surface, and the inclination angles of the first surface and the second surface are The angle is 0.5-3 ° with respect to the exit surface.
  • the pattern element has a quadrangular pyramid shape depressed in the light guide plate! / ⁇ .
  • the pitch P of the substantially square pyramid deflection pattern elements is constant s.
  • the pitch P of the substantially square pyramid deflection pattern elements is indefinite s.
  • the pattern element preferably has a quadrangular pyramid bottom surface that is a parallelogram.
  • angles ⁇ and ⁇ formed by the sides of the parallelogram are incident surfaces.
  • the 0 and the 0 are the same angle.
  • the parallelogram is formed by forming a straight line with one side of the parallelogram adjacent to each other among the four sides.
  • each of the parallelograms forms a straight line with one side of the adjacent parallelogram.
  • the pitch of a straight line group that forms an angle of 0 with the light incident surface P (1), P (2), ⁇ m (m) in order from the surface side, and the straight line group that forms an angle of ⁇ with the incident surface is a straight line group that forms an angle of 0 with the light incident surface P (1), P (2), ⁇ m (m) in order from the surface side, and the straight line group that forms an angle of ⁇ with the incident surface.
  • P (n) is preferably all the same value.
  • the numerical value of P (n) is preferably set by a random number.
  • the intermediate value of the ⁇ and the ⁇ is 30 to 30 respectively.
  • the range of the random number is the intermediate value ⁇ 15% or
  • a ridge line formed from the first surface and the second surface
  • the angle formed by the normal line of the incident surface is preferably within ⁇ 40 °.
  • the deflection pattern element is formed on a surface facing the emission surface, and another optical element is formed on the emission surface.
  • the other optical element is preferably an optical element having a function of diffusing or condensing emitted light.
  • the other optical element has anisotropic diffusibility.
  • another embodiment of the present invention is preferably a backlight device including the light guide plate and a liquid crystal display device.
  • the light guide plate according to the present invention is a plate-shaped light guide plate having an incident surface on a side surface and an output surface on an upper surface or a lower surface, and a general light guide plate on a surface facing the output surface.
  • Deflection pattern elements of roughly quadrangular pyramids formed in a decreasing direction with respect to the wall thickness are arranged adjacent to each other, and the shape of the quadrangular pyramid is formed integrally with the light guide plate except for the bottom surface of the quadrangular pyramid.
  • the first and second surfaces are the surfaces of the other third or fourth surface, respectively.
  • the ridgeline of the first and second surfaces is orthogonal to the incident surface, and the inclination angle of the first and second surfaces with respect to the exit surface is in the range of 0.5 to 3 degrees.
  • the first and second surfaces have approximately the same area, and the third and fourth surfaces have approximately the same area.
  • the approximate area means within ⁇ 10% of the intermediate value of the two areas.
  • a surface relief hologram is integrally formed on the exit surface side.
  • the pitch of the deflection pattern elements having a substantially quadrangular pyramid is constant.
  • the pitch of the deflecting pattern elements having a substantially quadrangular pyramid is indefinite.
  • the surface relief hologram has a plurality of linear random speckle regions that are long in a direction orthogonal to the incident surface.
  • the light diffusing characteristic of the surface relief hologram has a half-value angle of 30 to 70 degrees in the direction parallel to the incident surface, and is irregularly diffused at a half-value angle of 0.5 to 3 degrees in the orthogonal direction. .
  • a knocklight device includes the light guide plate having the above-described configuration.
  • FIG. 1 is a conceptual diagram showing a conventional light guide plate.
  • FIG. 2 is a diagram showing how the conventional light guide plate and backlight device are used.
  • FIG. 3 is a conceptual diagram showing a dod pattern deflection pattern element used in a conventional light guide plate.
  • FIG. 4 shows a conventional light guide plate with a V-shaped reflection groove.
  • FIG. 5 is a diagram in which a prism film is arranged on the upper surface of a conventional light guide plate.
  • FIG. 6 is a conceptual diagram for explaining the difference in brightness of a conventional light guide plate.
  • FIG. 7 is a conceptual diagram illustrating the light guide plate of the present invention, (a) is a top view of the light guide plate, (b) is a front view of the light guide plate, and (c) is a perspective view of the light guide plate. It is.
  • FIG. 8 shows a light guide plate of a type in which a deflection pattern element is recessed.
  • FIG. 9 shows a light guide plate of a type in which a deflection pattern element is projected.
  • FIG. 10 shows a conventional light guide plate including a straight V-shaped reflection groove method and a deflection pattern element. It is a conceptual diagram.
  • FIG. 11 shows a light guide plate of the present invention.
  • FIG. 12 is a conceptual diagram showing the operation of the first surface of the light guide plate of the present invention.
  • FIG. 13 is a diagram for explaining an interval between deflection pattern elements of the light guide plate of the present invention.
  • FIG. 14 is an enlarged view showing details of a hologram formed on the exit surface.
  • FIG. 15 is a top view showing a third embodiment of the light guide plate of the present invention.
  • FIG. 16 is an enlarged view showing details of a hologram formed on the exit surface.
  • FIG. 17 is a schematic view showing an example of a backlight device using the light guide plate of the present invention.
  • FIG. 18 is a diagram for explaining the action of a hologram.
  • FIG. 19 is a diagram showing an intensity distribution of emitted light.
  • FIG. 20 is a view showing a part of a backlight device (or a surface light source device) having a light guide plate and an optical sheet.
  • FIG. 21 is a diagram showing an intensity distribution of outgoing light.
  • FIG. 22 is a diagram showing a part of the knocklight device.
  • the xyz Cartesian coordinate system is set in the figure. That is, the X axis and the y axis are set along the two sides of the upper or lower surface of the light guide plate, and the incident direction of light from the light source is the X axis, and the direction perpendicular thereto is the y axis. Also set the z-axis in the normal direction of the exit surface. Also, the positive and negative directions of the z axis are referred to as up and down.
  • FIG. 6 is a perspective view showing a first embodiment of the light guide plate of the present invention.
  • FIG. 6 shows one form of arrangement of a light emitting diode (LED), an optical sheet (prism sheet) 6 and a liquid crystal 7 as the light source 2.
  • the light guide plate 1 is a plate having a substantially rectangular upper surface and lower surface.
  • the material constituting the light guide plate 1 is not particularly limited as long as it is a transparent material having a certain refractive index. Examples thereof include PMMA, polyolefin, polycarbonate, and the like.
  • the size of the light guide plate 1 varies depending on the application. For large applications such as 12 or 14-inch displays, 182.9 X 243.8 mm to 213.4 X 284.5 mm, 3 or 8 inch displays, etc. 45.7 X 81.0 mm to 121.9 X 162.6 mm for medium-sized applications, 1 or 2.8 15.2 X 20.3 mm to 42.7 X 56.9 mm for small applications such as 8-inch displays It is about the size.
  • the thickness is usually from 0.04 mm to 56.9 mm.
  • the incident surface 5 is provided on one side surface of the light guide plate, and the light from the light source 2 is efficiently incident on the light guide plate 1.
  • the incident surface 5 is often a flat surface, but a number of fine hairline grooves may be formed as shown in FIG. Such rubbing is preferable in that it is possible to improve luminance unevenness at the incident portion.
  • the processing to be formed on the incident surface 5 is not limited to the hairline groove, and conventionally known processing can be performed as necessary.
  • FIG. 7 is a drawing showing one shape of the deflection pattern element 17. Further, in FIG. 7, FIG. 7 (a) is a perspective view of the deflection pattern element 17, FIG. 7 (b) is a Vllb-Vllb cross-sectional view, and FIG. 7 (c) is a VIIc-VIIc cross-sectional view. .
  • the first and second surfaces 17a and 17b having a large area of the deflection pattern element 17 are mainly used as reflection surfaces for guiding incident light in the direction of the exit surface 3 of the light guide plate 1.
  • the first and second surfaces 17a and 17b having a large area are preferably 20 times or more the area of the other third and fourth surfaces, respectively.
  • the first and second surfaces 17a and 17b preferably have approximately the same area, and the third and fourth surfaces 17c and 17d preferably have approximately the same area.
  • the reflection surface 4 on which the deflection pattern element 17 as in the present embodiment is formed increases the light utilization efficiency of the light guide plate 1 with high efficiency in reflecting incident light in the direction of the emission surface 3.
  • the quadrangular pyramid deflection pattern element 17 has a ridge line 18 between the first surface 17a and the second surface 17b. Are arranged so as to face the direction orthogonal to the X-axis direction (X-axis direction).
  • the inclination angles of the first surface and the second surface are the inclinations of the third surface and the fourth surface, respectively. Smaller than the corner.
  • the first surface and the second surfaces 17a and 17b having a large area of the deflection pattern element 17 are mainly used as reflecting surfaces for guiding the incident light in the direction of the exit surface 3 of the light guide plate 1.
  • the first surface 17a and the second surface 17b having a large area are 10 times or more the area of the other third surface and the fourth surface, respectively, and preferably 15 times or more. More preferably.
  • the adjacent first surface 17a and second surface 17b have approximately the same area
  • the adjacent third surface 17c and fourth surface 17d also have approximately the same area.
  • the approximate area means that the difference in area is within twice.
  • the light guide plate of the present invention has a deflection pattern having four surface forces other than the bottom surface of the quadrangular pyramid.
  • there are two methods for forming four surfaces other than the bottom of the quadrangular pyramid that is, there are two types of such light guide plates.
  • One method is to flip the square pyramid in Fig. 7 (a) and press it against the light guide plate to form a deflection pattern. In this way, it is possible to obtain a light guide plate having a shape as shown in FIG. 8 in which a quadrangular pyramid shape in FIG.
  • the other is a method of arranging a large number of quadrangular pyramid shapes in FIG. 7 (a) as they are on the light guide plate. In this way, a light guide plate having the shape shown in FIG. 9 can be obtained.
  • the first surface 17a and the second surface 17b having a large area are arranged so as to face the direction of the light source, so that the light having the light source power can be deflected in the direction of the emission surface.
  • a light guide plate in which a quadrangular pyramid shape is recessed (d-signed) in the light guide plate is advantageous in terms of ease of manufacturing and optical characteristics.
  • the light guide plate 1 on which the deflection pattern element 17 as in the present embodiment is formed increases the efficiency of light utilization as a result of the high efficiency of reflecting incident light in the direction of the observer.
  • FIG. 10 is a top view of the light guide plate according to the first embodiment of the present invention.
  • the quadrangular pyramid deflection pattern element 17 has a ridge line 18 between the first surface 17a and the second surface 17b. Are arranged so as to face a direction (x-axis direction) orthogonal to the incident surface 5. In this way, since the ridge line 18 is aligned in the direction orthogonal to the incident surface 5 (X-axis direction), the outwardly extending shape (square shape) of each deflection pattern element 17 The shape of the bottom of the cone is a rhombus.
  • the left-side pitch of the light guide plate 1 (the pitch of the straight line group that forms an angle of 0 with the light incident surface)
  • P is expressed as P (1), ⁇ (2), ... ⁇ ( ⁇ ), all ⁇ are equally spaced,
  • P (m, n) If the deflection pattern element that also forms the nth pitch force is expressed as P (m, n), P (m, n) has a rhombus shape regardless of the number of m and n.
  • the interval between adjacent deflection pattern elements 17 is constant.
  • the value of Ps is preferably 30 to 500 m force S, more preferably 100 to 200 / ⁇ ⁇ force S, and further preferably 120 to 160 / ⁇ ⁇ .
  • the distance a between the exit surface 3 and the reflection surface 4 of the light guide plate 1 a is preferably 0.3 to 3.
  • Omm force S more preferably 0.35 to 0.8 mm force S, and 0. 4 ⁇ 0.8mm force especially preferred! / ⁇ .
  • angles (0 and 0) formed by the rhomboid sides of the deflection pattern element and the y-axis are
  • FIG. 11 is a cross-sectional view showing a part of the XI-XI cross section of FIG.
  • the deflection pattern element 17 has first and second surfaces 17a and 17b and third and fourth surfaces 17c and 17d, which are substantially quadrangular pyramidal reflecting surfaces facing the light source,
  • the first surface 17a and the second surface 17b have a predetermined angle ⁇ (inclination angle) with respect to a surface parallel to the emission surface 3.
  • inclination angle
  • the angle formed with the normal can be reduced.
  • the gradually raised light is emitted from the emission surface 3 when the angle formed with the normal line of the emission surface 3 is smaller than the critical angle. That is, the light incident on the incident surface 5 of the light guide plate 1 from the light source 2 repeats total reflection at the output surface 3 and the reflection surface 4 until the angle formed with the normal line of the output surface 3 reaches a critical angle, while the light guide plate 1 Go inside.
  • the angle a1 formed by the first and second surfaces 17a, 17b and the surface parallel to the emission surface 3 needs to be smaller than the inclination angle oc2 of the third surface and the fourth surface.
  • is smaller, the light gradually rises due to reflection from the first and second surfaces 17a and 17b, and the exit angle of the exit light from the exit surface 3 (the normal between the exit surface and the exit light). Is always almost equal to the critical angle. Therefore, the directions of light emitted from the emission surface 3 are aligned.
  • the angle ⁇ (inclination angle) between the first and second surfaces 17a, 17b and the plane parallel to the exit surface 3 is preferably 0.5 to 3 degrees. The degree is more preferable.
  • the angle between the third and fourth surfaces 17c, 17d and the plane parallel to the exit surface 3 (inclination angle between the third surface and the fourth surface) ⁇ 2 has little or no reflection effect. In order to avoid this, it is preferable to make it as large as possible. However, 90 degrees or less is preferable from the viewpoint of facilitating die cutting when the light guide plate 1 described later is formed. In order to achieve the above balance, ⁇ 2 is preferably 50 to 90 degrees, more preferably 55 to 87 degrees.
  • the interval Ps between the adjacent deflection pattern elements 17 is constant as shown in FIG.
  • the value of Ps is particularly preferably 120 to 160 / ⁇ ⁇ , more preferably 30 to 500 111, more preferably 100 to 200 m.
  • the distance a (light guide plate thickness) between the exit surface 3 and the reflection surface 4 of the light guide plate 1 is preferably 0.3 to 3. Omm, and more preferably 0.35 to 0.8 mm. 4 to 0.8 mm is particularly preferable.
  • FIG. 13 shows a method for making Ps random.
  • FIG. 13 is a plan view of the light guide plate 1 that has been processed so that Ps is random and the reflection surface 4 side force is seen.
  • the range of random numbers is preferably within ⁇ 15% of the above intermediate value or within ⁇ 20 / ⁇ .
  • the angle formed between the square side of the deflection pattern element and the y-axis is not particularly limited, but it is preferably 0 to 60 ° or more preferably 5 to 40 ° in terms of light utilization efficiency. ⁇ 20 ° is particularly preferred.
  • the angle between the sides of the parallelogram and the y-axis is 10 °
  • the intermediate value of P and P is 140 / ⁇ ⁇
  • each deflection pattern element is 236 to 316 m in the y-axis direction and 41 to 56 m in the x-axis direction.
  • the angle ⁇ of the ridgeline is in the range of ⁇ 39.01 ° from the X axis.
  • the angle of this ridge is preferably within ⁇ 40 °. In this way, it is expected that moire can be eliminated or reduced because each deflection pattern element shape has abundant randomness.
  • the parallelogram (or rhombus) on the bottom of the quadrangular pyramid of the deflection pattern element is such that each of the four sides forms a straight line with one side of the adjacent parallelogram.
  • one feature of the light guide plate of the present invention is that a large number of deflection pattern elements shown in FIG. 7 (a) are arranged. Since a light guide plate capable of providing a light device can be obtained, it is not always necessary to arrange as described above. In other words, by slightly shifting the parallelogram, as shown in Fig. 15, only two parallel sides of one side of the parallelogram or rhomboid force form a straight line with one side of the adjacent parallelogram. You may make it become. Such a form is difficult to manufacture as compared to the first and second embodiments, but on the other hand, “shift” gives randomness to the arrangement of the deflection pattern elements, improves appearance, eliminates moire, etc. It is also possible to obtain the effect.
  • the polarization pattern element in order to eliminate the dark part near the light source, is a parallelogram or rhombus.
  • the deflection pattern element must be a parallelogram or rhombus. There may be no.
  • the reflecting groove itself is a force that is a straight line in a direction parallel to the X axis or the y axis.
  • an anisotropic diffusion pattern having anisotropy is formed on the exit surface 3.
  • This anisotropic diffusion pattern has a light diffusion characteristic of half of 30 to 70 degrees in a direction parallel to the incident surface. More preferably, it is a value angle, and is irregularly diffused at a half-value angle of 0.5 to 3 degrees in the orthogonal direction.
  • a hologram is formed as the anisotropic diffusion pattern, and it is particularly preferable that this hologram is a surface relief hologram (in order to distinguish it from a three-dimensionally formed hologram). Called surface relief hologram). In this way, it has a plurality of long and linear random speckle regions in a direction perpendicular to the incident surface.
  • the backlight device using the light guide plate of the present invention is as shown in FIG.
  • the deflection pattern element 17 of the light guide plate may be provided on the exit surface 3.
  • the appearance near the light source 2 tends to be improved, and the luminance tends to be improved. Because, preferred.
  • Whether the deflection pattern element 17 is provided on the reflection surface 4 side as in the first embodiment, or whether the deflection pattern element 17 is provided on the emission surface 3 side as in the fourth embodiment, can be freely selected depending on the application. You can choose. For example, when the deflection pattern element 17 is provided on the exit surface 3 side, the appearance near the light source 2 is improved. On the other hand, depending on the prism sheet 6 used, a pattern like water bubbles is observed between the prism sheet 6 and the light guide plate 1. It may be done. On the other hand, in the first embodiment, the brightness and appearance are slightly inferior to those in the fourth embodiment, but since the deflection pattern element 17 is not formed on the exit surface, another processing is performed on the exit surface. Can be applied.
  • the exit surface can be roughened to reduce the unevenness of the exit light or to reduce moire.
  • the same rough surface processing can also be performed in the fourth embodiment, but the rough surface is arranged at a position farther than the observer's force, so that the effect is improved as compared with the first embodiment. Is inferior.
  • an anisotropic diffusion pattern having anisotropy is formed on the surface where the deflection pattern element 17 is not formed. More preferably, the diffusion characteristic is a half-value angle of 30 to 70 degrees in the direction parallel to the incident surface, and an irregular diffusion with a half-value angle of 0.5 to 3 degrees in the orthogonal direction.
  • a hologram is formed as the anisotropic diffusion pattern, and it is particularly preferable that this hologram is a surface relief hologram (in order to distinguish it from a three-dimensionally formed hologram). Called surface relief hologram). In this way, it has a plurality of long and linear random speckle regions in a direction perpendicular to the incident surface.
  • FIG. 18 and 19 are enlarged views showing details of the hologram 100 formed on the exit surface 3.
  • FIG. 18 is an enlarged view of the hologram enlarged 200 times, and FIG. It is an enlarged view.
  • FIG. 18 when the hologram is magnified to about 200 times, a large number of linear random speckles or random speckle regions extending in a direction perpendicular to the incident surface 4 (for example, other speckle regions) (Region having higher (or lower) transmittance) than the region (random grooves or irregularities) 100a.
  • the random speckle 100a has a random shape and a position that is not constant throughout the hologram.
  • the linear speckle 100a causes the light incident on the hologram to be diffused strongly in the direction parallel to the incident surface 5 and weak in the orthogonal direction.
  • the diffusion ratio of the diffusivity in the direction parallel to and perpendicular to the incident surface 5 is determined by the major and minor axis dimensions of the speckle.
  • the hologram has a function as a diffuser.
  • FIG. 20 is a diagram for explaining the operation of the hologram.
  • FIG. 20 (a) is a top view showing the angle dependence of the intensity of the light emitted from the points Pl and P2 on the exit surface 3 of the light guide plate 1.
  • FIG. 20 (b) is a perspective view showing a three-dimensional intensity distribution of light emitted from the point P2 on the exit surface 3 of the light guide plate 1.
  • Points PI, P2 force on the exit surface 3 of the light guide plate 1
  • the emitted light is parallel to the entrance surface 5 as shown by ellipses El, E2 by the hologram 100 formed on the exit surface 3.
  • the diffusion is strong in the direction and weak in the orthogonal direction.
  • FIG. 21 shows the intensity distribution of the emitted light.
  • FIG. 21 (a) shows the intensity distribution of the emitted light in the ⁇ direction
  • FIG. 21 (b) shows the intensity distribution of the emitted light in the r direction.
  • the half-width ⁇ of the diffusion angle ⁇ in the ⁇ direction is strongly diffused in the parallel direction ⁇ compared to the incident surface 5 and the orthogonal direction r, and the diffusion angle ⁇ in the r direction Than half width of ⁇
  • the half-value width ⁇ in the r direction is preferably 0.5 ⁇ ⁇ 3 degrees, more preferably 1 ⁇ ⁇ 2 degrees.
  • the half-width ⁇ in the ⁇ direction is preferably 30 to 70 degrees, more preferably 45 to 65 degrees.
  • the hologram Due to the anisotropic diffusion action of the hologram, a uniform intensity distribution of the emitted light in the 0 direction is realized in the light guide plate 1. In particular, the appearance of bright lines in the light emitted from the exit surface 3 is prevented.
  • FIG. 22 is a diagram showing a part of a backlight device (or a surface light source device) having a light guide plate and an optical sheet.
  • the light emitted from the light exit surface 3 of the light guide plate 1 is light L having components with small angles ⁇ 1, ⁇ 2 formed by the light exit surface 3.
  • the optical sheet 10 has a flat upper surface (10A)
  • Light L, L which has a prism-shaped lower surface (10B) and has a small angle with the light exit surface 3 of the light guide plate 1,
  • optical sheet are not particularly limited as long as they have a general prism structure.
  • examples thereof include M065HS (Mitsubishi Rayon), M168YS (Mitsubishi Rayon), and ⁇ - ⁇ (3 ⁇ ). These can be used singly or in combination of two or more or two or more.
  • the backlight device (or surface light source device) can be used as a backlight in a liquid crystal display device such as a mobile phone or an electronic notebook.
  • the light source may be a single-chip LED, a 2-chip LED, or a multi-chip LED as long as it is a point light source.

Abstract

A light guide plate (1) formed in a plate shape having a plane of incidence (5) on its side face and a plane of outgoing (3) on its upper or lower face. Polarizing pattern elements (17) of roughly quadrangular pyramid shape formed in a direction for reducing their wall thickness more than the wall thickness of the general wall thickness of the light guide plate (1) are arranged, adjacent to each other, on the surface thereof facing the plane of outgoing (3). The shape of the quadrangular pyramid is such that four faces thereof other than the bottom face are formed integrally with the light guide plate (1). The areas of the first and second faces of the four faces other than the bottom face are 20 times the areas of the other third or fourth face or larger, the ridge lines of the first and second faces perpendicularly crosses the plane of incidence (5), and the inclination angles of the first and second faces relative to the plane of outgoing (3) are within the range of 0.5 to 3°. The areas of the first and second faces are approximately the same and the areas of the third and fourth faces are approximately the same to prevent the brightness of the areas thereof near the plane of incidence from increasing or decreasing.

Description

明 細 書  Specification
導光板  Light guide plate
技術分野  Technical field
[0001] 本発明は、液晶表示素子などを背面から照射するバックライト装置に用いられる導 光板及び力かる導光板を具備するバックライト装置に関する。  The present invention relates to a light guide plate used in a backlight device that irradiates a liquid crystal display element or the like from the back and a backlight device including a powerful light guide plate.
背景技術  Background art
[0002] 従来、携帯電話機等の液晶表示装置を照明するため、光源から出射された光を液 晶表示装置に導く導光板及びこの導光板を備え液晶表示装置を背面から照明する ノ ックライト装置が提供されて ヽる。  Conventionally, in order to illuminate a liquid crystal display device such as a cellular phone, there is a light guide plate that guides light emitted from a light source to a liquid crystal display device, and a knock light device that includes the light guide plate and illuminates the liquid crystal display device from the back side. Provided.
[0003] 図 1は、液晶表示装置 10の外観を示す概略図である。図 1において、 1は導光板、 2は光源、 3は出射面、 4は反射面、 5は入射面、 6は偏向パターン素子、 7は液晶、 8 はリフレクタ、 9は光学シート、 11はホルダー、 12は光線、 13は観察者の視点である 。なお、液晶表示装置 10から液晶パネルを除いた状態でバックライト装置 14というこ とがある。  FIG. 1 is a schematic diagram showing an external appearance of the liquid crystal display device 10. In FIG. 1, 1 is a light guide plate, 2 is a light source, 3 is an exit surface, 4 is a reflection surface, 5 is an entrance surface, 6 is a deflection pattern element, 7 is a liquid crystal, 8 is a reflector, 9 is an optical sheet, and 11 is a holder. , 12 are rays, and 13 is the observer's viewpoint. In some cases, the backlight device 14 is a state where the liquid crystal panel is removed from the liquid crystal display device 10.
[0004] 導光板 1は、例えば PMMA又はポリカーボネートのような透明な材料力もなり、略 板状の平坦な形状を有している。そして、一つの側面を入射面 5とし、反射面 4には、 入射面 5から入射された光を出射面 3に向けて反射又は偏向するために複数の偏向 パターン素子 6による偏向パターンが形成されている。導光板 1は液晶パネル 7の下 に配置され、導光板 1の出射面 3と液晶パネル 7の下面とが対向するように配置され る。光源 2から出射された光線 12は、入射面 5から導光板 1に入射して導光板内部を 進み、反射面 4に形成された偏向パターン素子 6によって出射面 3の方向に立ち上 げられ、出射面 3から出射される。このように、側面にある入射面 5から入射された光 を主面にある出射面 3から出射する導光板 1をサイドエッジ方式と称し、携帯電話機 等において広く使用されている(例えば特許第 3151830号を参照)。  [0004] The light guide plate 1 also has a transparent material force such as PMMA or polycarbonate, and has a substantially plate-like flat shape. One side surface is defined as an incident surface 5, and a deflection pattern is formed on the reflecting surface 4 by a plurality of deflection pattern elements 6 in order to reflect or deflect the light incident from the incident surface 5 toward the exit surface 3. ing. The light guide plate 1 is disposed below the liquid crystal panel 7 and is disposed such that the light exit surface 3 of the light guide plate 1 and the lower surface of the liquid crystal panel 7 face each other. The light beam 12 emitted from the light source 2 enters the light guide plate 1 from the incident surface 5, travels inside the light guide plate, and rises in the direction of the output surface 3 by the deflection pattern element 6 formed on the reflection surface 4. The light exits from the exit surface 3. In this way, the light guide plate 1 that emits light incident from the incident surface 5 on the side surface from the output surface 3 on the main surface is referred to as a side edge method, and is widely used in mobile phones and the like (for example, Japanese Patent No. 3151830). Issue).
[0005] ところで、従来、レーザ光をディフューザの有する矩形の開口を介して感光フィルム を露光し、多数のスペックルをランダムに形成してなるホログラムが提供されている( 例えば米国特許第 5, 365, 354号公報及び米国特許第 5, 534, 386号公報を参 照)。このホログラムにおいて、スペックルは略楕円形状を有し、楕円の長軸と短軸は 、開口の矩形の短辺と長辺とフーリエ変換の関係を有する。このホログラムにレーザ 光を入射すると、レーザ光は各スペックルによって散乱され、露光の際に用いられた 矩形状の開口を再現する。このようなホログラムを用いることで、入射光を異方的に拡 散することができる。 [0005] By the way, conventionally, there has been provided a hologram obtained by exposing a photosensitive film through a rectangular opening having a diffuser to form a large number of speckles at random (for example, US Pat. No. 5,365). No. 354 and U.S. Pat.No. 5,534,386. See). In this hologram, the speckle has a substantially elliptical shape, and the major and minor axes of the ellipse have a relationship of Fourier transform with the short and long sides of the rectangular opening. When laser light is incident on this hologram, the laser light is scattered by each speckle and reproduces the rectangular opening used for the exposure. By using such a hologram, incident light can be diffused anisotropically.
発明の開示  Disclosure of the invention
[0006] 従来の導光板においては、偏向パターン素子は図 2 (a)に示すようなドッドパターン 15が一般的であった。しかし、偏向パターン素子が独立した概円形パターンである ため、図 2 (b)に示すように、偏向パターン素子により反射した光が一定方向に出射 せず、結果として、出射光は拡散し輝度を高めることが困難であるという課題があった  In a conventional light guide plate, the deflection pattern element is generally a dodd pattern 15 as shown in FIG. 2 (a). However, since the deflection pattern element is an independent almost circular pattern, the light reflected by the deflection pattern element is not emitted in a certain direction as shown in Fig. 2 (b). There was a problem that it was difficult to increase
[0007] そこで近年では、このような輝度低下を防止するため、図 3 (a)に示すような、概 V字 型の偏向パターン素子を施した導光板が主流となってきて 、る。この V字溝型の偏向 ノターン素子は、一般的には、図 3 (b)の上面図に示されるように、上記 V字溝の方 向が入射面と平行となるように設けられて ヽる。 [0007] Therefore, in recent years, in order to prevent such a decrease in luminance, a light guide plate provided with a substantially V-shaped deflection pattern element as shown in FIG. 3 (a) has become mainstream. This V-shaped grooved deflection element is generally provided so that the direction of the V-shaped groove is parallel to the incident surface as shown in the top view of FIG. The
[0008] この方式は、図 4に示すように出射光線 12が比較的整列するため、導光板 1の上 面に隣接させた光学シート 9により、光線 12を効率的に正面方向へと導くことができ、 高輝度化を図ることができる。  In this method, as shown in FIG. 4, since the emitted light beams 12 are relatively aligned, the light sheet 12 is efficiently guided in the front direction by the optical sheet 9 adjacent to the upper surface of the light guide plate 1. And high brightness can be achieved.
[0009] しかし、この構造である場合、光源 2の入光面付近では図 5 (a)に示すような暗部 15 が発生しやすい難点があった。この理由を、図 5 (b)を用いて説明する。図 5 (b)は図 5 (a)を光源 2の方向からみた側面図である。光源 2からの光線は、入射面 5から導光 板 1内に入射する。従来の導光板のように反射溝が直線であると、光源 2から出光さ れた光線のうち、光線 12aは上面に配置されるプリズムフィルム 10により正面方向に 偏向される光線軌跡となる。しかし、光線 12b (斜め光)は、直線状の反射面により大 きく偏向され、プリズムフィルム 10によって正面方向に偏向できる光線軌跡力も離脱 するため、光の出射量の少ない部分が生じてしまい、そこが暗部となって観察される という問題があった。  However, in the case of this structure, there is a problem that a dark portion 15 as shown in FIG. 5 (a) is likely to occur in the vicinity of the light incident surface of the light source 2. The reason for this will be described with reference to FIG. FIG. 5 (b) is a side view of FIG. 5 (a) viewed from the direction of the light source 2. FIG. Light from the light source 2 enters the light guide plate 1 from the incident surface 5. When the reflection groove is a straight line as in the conventional light guide plate, among the light beams emitted from the light source 2, the light beam 12a becomes a light beam locus deflected in the front direction by the prism film 10 disposed on the upper surface. However, the light beam 12b (oblique light) is largely deflected by the linear reflecting surface, and the ray trajectory force that can be deflected in the front direction by the prism film 10 is also released, so that a portion with a small amount of light emission is generated. Was observed in the dark.
[0010] 本発明は、上述の実情に鑑みて提案されるものであって、入射面付近の輝度明暗 を防止した導光板及び力かる導光板を具備するバックライト装置を提供することを目 的とする。 [0010] The present invention has been proposed in view of the above-described circumstances, and brightness brightness / darkness in the vicinity of an incident surface is proposed. It is an object of the present invention to provide a backlight device including a light guide plate that prevents the occurrence of light and a powerful light guide plate.
[0011] 本発明は、導光板に概四角錐反射溝を形成することにより、光線 12a, 12bともに、 上面に配置されるプリズムフィルムの偏向により、正面方向に光線軌跡が導き易ぐ V 字溝の難点である入射面付近の輝度明暗を防止できるものである。  In the present invention, by forming a substantially quadrangular pyramid reflection groove on the light guide plate, both the light rays 12a and 12b can be easily guided in the front direction by the deflection of the prism film disposed on the upper surface. It is possible to prevent brightness contrast in the vicinity of the incident surface, which is a difficult point.
[0012] 本発明の実施形態は、側面に入射面を有し、上面又は下面に出射面を有する板 状の導光板であって、前記出射面又は前記出射面と対向する面に、複数の偏向パ ターン素子が配列しており、該偏向パターン素子は、四角錐の底面以外の 4つの面 力 導光板に一体形成された四角錐形状を有してなり、前記 4つの面のうち、隣接す る第 1面と第 2面のそれぞれの面積は、隣接する第 3面と第 4面のそれぞれの面積の 20倍以上であり、前記第 1面及び前記第 2面のそれぞれの傾斜角は、前記出射面に 対して 0. 5〜3° である。  An embodiment of the present invention is a plate-shaped light guide plate having an incident surface on a side surface and an output surface on an upper surface or a lower surface, and a plurality of light guide plates on the output surface or the surface facing the output surface. A deflection pattern element is arranged, and the deflection pattern element has a quadrangular pyramid shape integrally formed on the light guide plate with four surface forces other than the bottom surface of the quadrangular pyramid. The area of each of the first surface and the second surface is 20 times or more of the area of each of the adjacent third surface and the fourth surface, and the inclination angles of the first surface and the second surface are The angle is 0.5-3 ° with respect to the exit surface.
[0013] また、本発明の他の実施形態は、前記パターン素子は、四角錐形状が導光板に凹 設 (depressed)されることが好まし!/ヽ。  In another embodiment of the present invention, it is preferable that the pattern element has a quadrangular pyramid shape depressed in the light guide plate! / 板.
[0014] また、本発明の他の実施形態は、概四角錐の偏向パターン素子のピッチ Pが一定 s であることが好ましい。  In another embodiment of the present invention, it is preferable that the pitch P of the substantially square pyramid deflection pattern elements is constant s.
[0015] また、本発明の他の実施形態は、概四角錐の偏向パターン素子のピッチ Pが不定 s であることが好ましい。  In another embodiment of the present invention, it is preferable that the pitch P of the substantially square pyramid deflection pattern elements is indefinite s.
[0016] 前記パターン素子は、四角錐形状の底面が平行四辺形であることが好ましい。  [0016] The pattern element preferably has a quadrangular pyramid bottom surface that is a parallelogram.
[0017] また、本発明の他の実施形態は、前記平行四辺形の辺が入射面なす角 Θ 及び Θ [0017] In another embodiment of the present invention, the angles Θ and Θ formed by the sides of the parallelogram are incident surfaces.
R  R
は、それぞれ 0を超え 60° 以下であることが好ましい。  Are preferably more than 0 and 60 ° or less.
 Shi
[0018] また、本発明の他の実施形態は、前記 0 と前記 0 は同じ角度であることが好まし  [0018] In another embodiment of the present invention, it is preferable that the 0 and the 0 are the same angle.
L R  L R
い。  Yes.
[0019] また、本発明の他の実施形態は、前記平行四辺形は、四辺のうち一糸且の平行な二 辺力 隣接する平行四辺形の一辺と直線を形成してなることが好ましい。  [0019] In another embodiment of the present invention, it is preferable that the parallelogram is formed by forming a straight line with one side of the parallelogram adjacent to each other among the four sides.
[0020] また、本発明の他の実施形態は、前記平行四辺形は、四辺のそれぞれが、隣接す る平行四辺形の一辺と直線を形成してなることが好ましい。  [0020] In another embodiment of the present invention, it is preferable that each of the parallelograms forms a straight line with one side of the adjacent parallelogram.
[0021] また、本発明の他の実施形態は、入光面と 0 の角をなす直線群のピッチを、入光 面側から順に P ( 1)、 P (2)、 · · · Ρ (m)と表し、入光面と Θ の角をなす直線群のピ In another embodiment of the present invention, the pitch of a straight line group that forms an angle of 0 with the light incident surface P (1), P (2), Ρ m (m) in order from the surface side, and the straight line group that forms an angle of Θ with the incident surface.
L L L R  L L L R
ツチを、入光面側から順に P ( 1)、Ρ (2)、 · · · Ρ (η)、として表したとき、 P (m)及び  When the tabs are expressed as P (1), Ρ (2), Ρ (η) in order from the light incident side, P (m) and
R R R し  R R R
P (n)が全て同じ値であることが好ましい。  P (n) is preferably all the same value.
R  R
[0022] また、本発明の他の実施形態は、入光面と 0 の角をなす直線群のピッチを、入光  In another embodiment of the present invention, the pitch of a straight line group that forms an angle of 0 with the light incident surface
 Shi
面側から順に P ( 1)、 P (2)、 · · · Ρ (m)と表し、入光面と Θ の角をなす直線群のピ  P (1), P (2), Ρ m (m) in order from the surface side, and the straight line group that forms an angle of Θ with the incident surface.
L L L R  L L L R
ツチを、入光面側から順に P ( 1)、Ρ (2)、 · · · Ρ (η)、として表したとき、 P (m)及び  When the tabs are expressed as P (1), Ρ (2), Ρ (η) in order from the light incident side, P (m) and
R R R し  R R R
P (n)がの数値は、乱数で設定されてなることが好ましい。  The numerical value of P (n) is preferably set by a random number.
R  R
[0023] また、本発明の他の実施形態は、前記 P及び前記 P力 P ( 1) = P ( 1)、 P (2)  [0023] Further, in another embodiment of the present invention, the P and the P force P (1) = P (1), P (2)
L R L R L  L R L R L
= Ρ (2)、 · · · Ρ (η) = Ρ (η)の関係を満たすことが好ましい。  = Ρ (2), Ρ (η) = Ρ (η) is preferably satisfied.
R L R  R L R
[0024] また、本発明の他の実施形態は、前記 Ρ及び前記 Ρの中間値は、それぞれ 30〜  [0024] In another embodiment of the present invention, the intermediate value of the Ρ and the Ρ is 30 to 30 respectively.
L R  L R
500 μ mであることが好まし!/、。  It is preferable to be 500 μm! /.
[0025] また、本発明の他の実施形態は、前記乱数の範囲は、前記中間値 ± 15%又は士[0025] In another embodiment of the present invention, the range of the random number is the intermediate value ± 15% or
20 μ mであることが好まし!/ヽ。 20 μm is preferred! / ヽ.
[0026] また、本発明の他の実施形態は、前記第 1面及び前記第 2面から形成される稜線と[0026] Further, in another embodiment of the present invention, a ridge line formed from the first surface and the second surface,
、前記入射面の法線のなす角が ±40° 以内であることが好ましい。 The angle formed by the normal line of the incident surface is preferably within ± 40 °.
[0027] また、本発明の他の実施形態は、前記偏向パターン素子が前記出射面と対向する 面に形成され、出射面には他の光学素子が形成されてなることが好ましい。 In another embodiment of the present invention, it is preferable that the deflection pattern element is formed on a surface facing the emission surface, and another optical element is formed on the emission surface.
[0028] また、本発明の他の実施形態は、前記他の光学素子が、出射光の拡散又は集光 する機能を有する光学素子であることが好まし 、。 [0028] In another embodiment of the present invention, the other optical element is preferably an optical element having a function of diffusing or condensing emitted light.
[0029] また、本発明の他の実施形態は、前記他の光学素子が、異方拡散性を有してなる ことが好ましい。 In another embodiment of the present invention, it is preferable that the other optical element has anisotropic diffusibility.
[0030] また、本発明の他の実施形態は、上記導光板を備えるバックライト装置、及び液晶 表示装置であることが好ま 、。  [0030] Further, another embodiment of the present invention is preferably a backlight device including the light guide plate and a liquid crystal display device.
[0031] また、本発明に係る導光板は、側面に入射面を有し、上面又は下面に出射面を有 する板状の導光板にして、前記出射面と対向する面に導光板の一般肉厚に対し、減 ずる方向に形成された概略四角錐の偏向パターン素子が隣接し配列しており、その 四角錐の形状は、四角錐の底面以外の 4面が導光板に一体形成されたものであって 、底面以外の 4面のうち、第 1及び第 2の面は、それぞれ他の第 3又は第 4の面の面 積の 20倍以上あり、前記第 1及び第 2の面の稜線が入射面と直交し、前記第 1及び 第 2の面の前記出射面に対する傾斜角は 0. 5〜3度の範囲であり、前記第 1及び第 2の面は概同面積であり、前記第 3及び第 4の面は概同面積であるものであることが 好ましい。ここで、概同面積とは、 2面積の中間値の ± 10%以内であることをいう。 [0031] Further, the light guide plate according to the present invention is a plate-shaped light guide plate having an incident surface on a side surface and an output surface on an upper surface or a lower surface, and a general light guide plate on a surface facing the output surface. Deflection pattern elements of roughly quadrangular pyramids formed in a decreasing direction with respect to the wall thickness are arranged adjacent to each other, and the shape of the quadrangular pyramid is formed integrally with the light guide plate except for the bottom surface of the quadrangular pyramid. Of the four surfaces other than the bottom surface, the first and second surfaces are the surfaces of the other third or fourth surface, respectively. More than 20 times the product, the ridgeline of the first and second surfaces is orthogonal to the incident surface, and the inclination angle of the first and second surfaces with respect to the exit surface is in the range of 0.5 to 3 degrees. Preferably, the first and second surfaces have approximately the same area, and the third and fourth surfaces have approximately the same area. Here, the approximate area means within ± 10% of the intermediate value of the two areas.
[0032] 出射面側にサーフェスレリーフホログラムを一体的に成形したことが好ましい。 [0032] Preferably, a surface relief hologram is integrally formed on the exit surface side.
[0033] 概四角錐の偏向パターン素子のピッチが一定であることが好ましい。 [0033] It is preferable that the pitch of the deflection pattern elements having a substantially quadrangular pyramid is constant.
[0034] 概四角錐の偏向パターン素子のピッチが不定であることが好ましい。 [0034] It is preferable that the pitch of the deflecting pattern elements having a substantially quadrangular pyramid is indefinite.
[0035] 前記サーフェスレリーフホログラムは、入射面と直交する方向に長!、線状の複数の ランダムスペックル領域を有することが好まし 、。 [0035] Preferably, the surface relief hologram has a plurality of linear random speckle regions that are long in a direction orthogonal to the incident surface.
[0036] 前記サーフェスレリーフホログラムの光拡散特性が入射面と平行方向に 30〜70度 の半値角であり、直交する方向に 0. 5〜3度の半値角で異形拡散することが好まし い。 [0036] It is preferable that the light diffusing characteristic of the surface relief hologram has a half-value angle of 30 to 70 degrees in the direction parallel to the incident surface, and is irregularly diffused at a half-value angle of 0.5 to 3 degrees in the orthogonal direction. .
[0037] 本発明に係るノ ックライト装置は、前述の構成の導光板を備えてなるものである。  [0037] A knocklight device according to the present invention includes the light guide plate having the above-described configuration.
[0038] 本発明によると、導光板及び導光板を備えるバックライト装置における入射面付近 の明暗差という課題を解決することができる。 [0038] According to the present invention, it is possible to solve the problem of light / dark difference in the vicinity of an incident surface in a light guide plate and a backlight device including the light guide plate.
図面の簡単な説明  Brief Description of Drawings
[0039] [図 1]図 1は、従来の導光板を示す概念図である。 FIG. 1 is a conceptual diagram showing a conventional light guide plate.
[図 2]図 2は、従来の導光板及びバックライト装置の使用態様を示す図である。  FIG. 2 is a diagram showing how the conventional light guide plate and backlight device are used.
[図 3]図 3は、従来の導光板に用いられるドッドパターンの偏向パターン素子を示す 概念図である。  FIG. 3 is a conceptual diagram showing a dod pattern deflection pattern element used in a conventional light guide plate.
[図 4]図 4は、従来の V字型の反射溝を施した導光板である。  [FIG. 4] FIG. 4 shows a conventional light guide plate with a V-shaped reflection groove.
[図 5]図 5は、従来の導光板上面にプリズムフィルムを配した図である。  FIG. 5 is a diagram in which a prism film is arranged on the upper surface of a conventional light guide plate.
[図 6]図 6は、従来の導光板の明暗差を説明するための概念図である。  FIG. 6 is a conceptual diagram for explaining the difference in brightness of a conventional light guide plate.
[図 7]図 7は、本発明の導光板を説明する概念図であり、(a)は導光板の上面図、(b) は導光板の正面図、(c)は導光板の斜視図である。  FIG. 7 is a conceptual diagram illustrating the light guide plate of the present invention, (a) is a top view of the light guide plate, (b) is a front view of the light guide plate, and (c) is a perspective view of the light guide plate. It is.
[図 8]図 8は、偏向パターン素子が凹設されたタイプの導光板である。  FIG. 8 shows a light guide plate of a type in which a deflection pattern element is recessed.
[図 9]図 9は、偏向パターン素子が凸設されたタイプの導光板である。  [FIG. 9] FIG. 9 shows a light guide plate of a type in which a deflection pattern element is projected.
[図 10]図 10は、従来の直線 V字型反射溝方式と偏向パターン素子を含む導光板の 概念図である。 [FIG. 10] FIG. 10 shows a conventional light guide plate including a straight V-shaped reflection groove method and a deflection pattern element. It is a conceptual diagram.
[図 11]図 11は、本発明の導光板である。  FIG. 11 shows a light guide plate of the present invention.
[図 12]図 12は、本発明の導光板の第 1面の作用を示す概念図である。  FIG. 12 is a conceptual diagram showing the operation of the first surface of the light guide plate of the present invention.
[図 13]図 13は、本発明の導光板の偏向パターン素子の間隔を説明する図である。  FIG. 13 is a diagram for explaining an interval between deflection pattern elements of the light guide plate of the present invention.
[図 14]図 14は、出射面に形成されたホログラムの詳細を示す拡大図である。  FIG. 14 is an enlarged view showing details of a hologram formed on the exit surface.
[図 15]図 15は、本発明の導光板の第 3の実施態様を示す上面図である。  FIG. 15 is a top view showing a third embodiment of the light guide plate of the present invention.
[図 16]図 16は、出射面に形成されたホログラムの詳細を示す拡大図である。  FIG. 16 is an enlarged view showing details of a hologram formed on the exit surface.
[図 17]図 17は、本発明の導光板を使用したバックライト装置の一例を示す概略図で ある。  FIG. 17 is a schematic view showing an example of a backlight device using the light guide plate of the present invention.
[図 18]図 18は、ホログラムの作用を説明する図である。  FIG. 18 is a diagram for explaining the action of a hologram.
[図 19]図 19は、出射光の強度分布を示す図である。  FIG. 19 is a diagram showing an intensity distribution of emitted light.
[図 20]図 20は、導光板と光学シートを有するバックライト装置 (又は面光源装置)の一 部を示す図である。  FIG. 20 is a view showing a part of a backlight device (or a surface light source device) having a light guide plate and an optical sheet.
[図 21]図 21は、出射光の強度分布を示す図である。  FIG. 21 is a diagram showing an intensity distribution of outgoing light.
[図 22]図 22は、ノ ックライト装置の一部を示す図である。  FIG. 22 is a diagram showing a part of the knocklight device.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0040] 以下、本発明に係る導光板及びバックライト装置の実施形態について図面を参照 して詳細に説明する。本実施の形態においては、簡単のため、幾つかの異なる図面 において共通の指示符合によって同一の部材を示す。また、本実施の形態の図面 は、本発明の内容を説明するために用いられるものであり、各部の寸法の比率を正 確に反映するものではない。また、参照の便宜上、図中に xyz直交座標系を設定す る。すなわち、導光板の上面又は下面の 2つの辺に沿って X軸及び y軸を設定し、光 源からの光の入射方向を X軸、これに垂直な方向を y軸とする。また、出射面の法線 方向に z軸を設定する。また、 z軸の正負方向を上下と称する。  Hereinafter, embodiments of a light guide plate and a backlight device according to the present invention will be described in detail with reference to the drawings. In the present embodiment, for the sake of simplicity, the same members are indicated by common reference symbols in several different drawings. The drawings of the present embodiment are used for explaining the contents of the present invention, and do not accurately reflect the ratio of the dimensions of each part. For reference purposes, the xyz Cartesian coordinate system is set in the figure. That is, the X axis and the y axis are set along the two sides of the upper or lower surface of the light guide plate, and the incident direction of light from the light source is the X axis, and the direction perpendicular thereto is the y axis. Also set the z-axis in the normal direction of the exit surface. Also, the positive and negative directions of the z axis are referred to as up and down.
[0041] (第 1の実施態様)  [0041] (First embodiment)
図 6は、本発明の導光板の第 1実施態様を示す斜視図である。図 6には、理解のた め光源 2としての発光ダイオード (LED)、光学シート(プリズムシート) 6及び液晶 7の 配置の一形態を図示してある。導光板 1は、略矩形状の上面及び下面を有する板状 の形状を有し、光源 2からの光を入射させる入射面 5と、光を上方に出射する出射面 3と、入射面 5からの入射光又は出射面 3からの反射光を反射する反射面 4と、を有 する。 FIG. 6 is a perspective view showing a first embodiment of the light guide plate of the present invention. For the sake of understanding, FIG. 6 shows one form of arrangement of a light emitting diode (LED), an optical sheet (prism sheet) 6 and a liquid crystal 7 as the light source 2. The light guide plate 1 is a plate having a substantially rectangular upper surface and lower surface. The incident surface 5 on which light from the light source 2 is incident, the output surface 3 that emits light upward, and the reflective surface that reflects incident light from the incident surface 5 or reflected light from the output surface 3 4 and.
[0042] 導光板 1を構成する材料としては、一定の屈折率を有する透明な材料であれば特 に制限はなぐ例えば、 PMMA、ポリオレフイン又はポリカーボネート等が挙げられる 。また、導光板 1の大きさは、用途によって異なる力 12または 14インチディスプレイ 等の大型用途であれば 182. 9 X 243. 8mm〜213. 4 X 284. 5mm, 3または 8ィ ンチディスプレイ等の中型用途であれば 45. 7 X 81. 0mm〜121. 9 X 162. 6mm 、 1または 2. 8インチディスプレイ等の小型用途であれば 15. 2 X 20. 3mm〜42. 7 X 56. 9mm程度の大きさである。また、厚みは、通常 0. 04mm〜56. 9mmである。  [0042] The material constituting the light guide plate 1 is not particularly limited as long as it is a transparent material having a certain refractive index. Examples thereof include PMMA, polyolefin, polycarbonate, and the like. The size of the light guide plate 1 varies depending on the application. For large applications such as 12 or 14-inch displays, 182.9 X 243.8 mm to 213.4 X 284.5 mm, 3 or 8 inch displays, etc. 45.7 X 81.0 mm to 121.9 X 162.6 mm for medium-sized applications, 1 or 2.8 15.2 X 20.3 mm to 42.7 X 56.9 mm for small applications such as 8-inch displays It is about the size. The thickness is usually from 0.04 mm to 56.9 mm.
[0043] 入射面 5は、導光板の一側面に設けられ、光源 2からの光は、導光板 1へ効率的に 入射される。入射面 5は平面であることが多いが、図 6に示すように、多数の細かいへ ァライン溝が形成されていてもよい。このよう〖こすると、入射部の輝度ムラを改善する ことができる点で好ましい。また、入射面 5に形成する加工はヘアライン溝に限定され るものではなぐ従来公知の加工を必要に応じて行うことができる。  The incident surface 5 is provided on one side surface of the light guide plate, and the light from the light source 2 is efficiently incident on the light guide plate 1. The incident surface 5 is often a flat surface, but a number of fine hairline grooves may be formed as shown in FIG. Such rubbing is preferable in that it is possible to improve luminance unevenness at the incident portion. Further, the processing to be formed on the incident surface 5 is not limited to the hairline groove, and conventionally known processing can be performed as necessary.
[0044] 反射面 4には、四角錐の底面以外の 4つの面が導光板に形成された、概四角錐の 偏向パターン素子 17形状が連続的に配列されている。図 7は偏向パターン素子 17 の一つの形状を示す図面である。また、図 7において、図 7 (a)は偏向パターン素子 1 7の斜視図であり、図 7 (b)は Vllb— Vllb断面図であり、図 7 (c)は VIIc— VIIc断面図 である。  [0044] On the reflecting surface 4, the shape of a substantially quadrangular pyramid deflection pattern element 17 in which four surfaces other than the bottom surface of the quadrangular pyramid are formed on the light guide plate is continuously arranged. FIG. 7 is a drawing showing one shape of the deflection pattern element 17. Further, in FIG. 7, FIG. 7 (a) is a perspective view of the deflection pattern element 17, FIG. 7 (b) is a Vllb-Vllb cross-sectional view, and FIG. 7 (c) is a VIIc-VIIc cross-sectional view. .
[0045] 偏向ノターン素子 17の面積が大きい第 1及び第 2面 17a, 17bが、入射光を導光 板 1の出射面 3方向へ導くための反射面として主に使用される。ここで、面積が大き い第 1及び第 2面 17a, 17bは、それぞれ他の第 3及び第 4の面の面積の 20倍以上 であることが好ましい。また、第 1及び第 2の面 17a, 17bは概同面積であり、第 3及び 第 4の面 17c, 17dも概同面積であることが好ましい。  [0045] The first and second surfaces 17a and 17b having a large area of the deflection pattern element 17 are mainly used as reflection surfaces for guiding incident light in the direction of the exit surface 3 of the light guide plate 1. Here, the first and second surfaces 17a and 17b having a large area are preferably 20 times or more the area of the other third and fourth surfaces, respectively. The first and second surfaces 17a and 17b preferably have approximately the same area, and the third and fourth surfaces 17c and 17d preferably have approximately the same area.
[0046] 従って、本実施形態のような偏向パターン素子 17を形成した反射面 4は、入射され た光を出射面 3方向に反射する効率が高ぐ導光板 1の光利用効率を高める。そして 、四角錐の偏向パターン素子 17は、第 1面 17aと第 2面 17bとの稜線 18が、入射面 5 と直交する方向(X軸方向)を向くように配列されて 、る。 Therefore, the reflection surface 4 on which the deflection pattern element 17 as in the present embodiment is formed increases the light utilization efficiency of the light guide plate 1 with high efficiency in reflecting incident light in the direction of the emission surface 3. The quadrangular pyramid deflection pattern element 17 has a ridge line 18 between the first surface 17a and the second surface 17b. Are arranged so as to face the direction orthogonal to the X-axis direction (X-axis direction).
[0047] また、本発明の導光板において、偏向パターン素子 17において、第 1面及び第 2 面のそれぞれの傾斜角(出射面に対する傾き)は、前記第 3面及び第 4面のそれぞれ の傾斜角より小さい。そうすると、偏向パターン素子 17の面積が大きい第 1面及び第 2面 17a, 17bが、入射光を導光板 1の出射面 3方向へ導くための反射面として主に 使用される。ここで、面積が大きい第 1面 17a及び第 2面 17bは、それぞれ他の第 3面 及び第 4面の面積の 10倍以上であり、 15倍以上であることが好ましぐ 20倍以上で あることがより好ましい。また、隣接する第 1面 17a及び第 2面 17bは概同面積であり、 隣接する第 3の面 17c及び第 4の面 17dも概同面積であることが好ましい。ここで概 同面積とは、面積の差が 2倍以内であることを意味する。  In the light guide plate of the present invention, in the deflection pattern element 17, the inclination angles of the first surface and the second surface (inclination with respect to the emission surface) are the inclinations of the third surface and the fourth surface, respectively. Smaller than the corner. Then, the first surface and the second surfaces 17a and 17b having a large area of the deflection pattern element 17 are mainly used as reflecting surfaces for guiding the incident light in the direction of the exit surface 3 of the light guide plate 1. Here, the first surface 17a and the second surface 17b having a large area are 10 times or more the area of the other third surface and the fourth surface, respectively, and preferably 15 times or more. More preferably. Further, it is preferable that the adjacent first surface 17a and second surface 17b have approximately the same area, and the adjacent third surface 17c and fourth surface 17d also have approximately the same area. Here, the approximate area means that the difference in area is within twice.
[0048] 本発明の導光板は、四角錐の底面以外の 4つの面力 なる偏向パターンを有して なることはすでに説明したとおりである。しかし、四角錐の底面以外の 4つの面を形成 する方法は 2種あり、すなわちこのような導光板も 2種ある。一つの方法は、図 7 (a)の 四角錐をひっくり返して、導光板に押しつけることにより偏向パターンを形成する方法 である。このようにすると、図 7 (a)四角錐形状が導光板に凹設 (d印 ressed)された図 8 に示すような形状の導光板を得ることができる。もう一つは、図 7 (a)の四角錐形状を そのまま導光板に多数配列する方法であり、このようにすると、図 9に示すような形状 の導光板を得ることができる。  [0048] As described above, the light guide plate of the present invention has a deflection pattern having four surface forces other than the bottom surface of the quadrangular pyramid. However, there are two methods for forming four surfaces other than the bottom of the quadrangular pyramid, that is, there are two types of such light guide plates. One method is to flip the square pyramid in Fig. 7 (a) and press it against the light guide plate to form a deflection pattern. In this way, it is possible to obtain a light guide plate having a shape as shown in FIG. 8 in which a quadrangular pyramid shape in FIG. The other is a method of arranging a large number of quadrangular pyramid shapes in FIG. 7 (a) as they are on the light guide plate. In this way, a light guide plate having the shape shown in FIG. 9 can be obtained.
[0049] いずれの導光板も、面積の大きい第 1面 17a及び第 2面 17bが、光源の方向を向く ように配置することによって、光源力も入射された光を出射面方向に偏向させることが できるが、製造法の容易さや光学特性の点で、四角錐形状が導光板に凹設 (d印 ress ed)された導光板が有利である。  [0049] In any light guide plate, the first surface 17a and the second surface 17b having a large area are arranged so as to face the direction of the light source, so that the light having the light source power can be deflected in the direction of the emission surface. However, a light guide plate in which a quadrangular pyramid shape is recessed (d-signed) in the light guide plate is advantageous in terms of ease of manufacturing and optical characteristics.
[0050] このように、本実施形態のような偏向パターン素子 17を形成した導光板 1は、入射 された光を観察者の方向に反射する効率が高ぐ結果として光利用効率を高める。  As described above, the light guide plate 1 on which the deflection pattern element 17 as in the present embodiment is formed increases the efficiency of light utilization as a result of the high efficiency of reflecting incident light in the direction of the observer.
[0051] 図 10は、本発明の、第 1の実施態様の導光板の上面図であり、四角錐の偏向バタ ーン素子 17は、第 1面 17aと第 2面 17bとの稜線 18が、入射面 5と直交する方向(x 軸方向)を向くように配列されている。このように、稜線 18が、入射面 5直交する方向( X軸方向)に整列しているため、一つ一つの偏向パターン素子 17の外延形状(四角 錐の底面の形状)は菱形となる。 FIG. 10 is a top view of the light guide plate according to the first embodiment of the present invention. The quadrangular pyramid deflection pattern element 17 has a ridge line 18 between the first surface 17a and the second surface 17b. Are arranged so as to face a direction (x-axis direction) orthogonal to the incident surface 5. In this way, since the ridge line 18 is aligned in the direction orthogonal to the incident surface 5 (X-axis direction), the outwardly extending shape (square shape) of each deflection pattern element 17 The shape of the bottom of the cone is a rhombus.
[0052] 図 10において、導光板 1の左側ピッチ (入光面と 0 の角をなす直線群のピッチ)を  [0052] In FIG. 10, the left-side pitch of the light guide plate 1 (the pitch of the straight line group that forms an angle of 0 with the light incident surface)
 Shi
P (1)、 P (2)、 · · ·Ρ (m)、導光板 1の右側ピッチ (入光面と Θ の角をなす直線群 P (1), P (2), ... Ρ (m), right-hand pitch of light guide plate 1 (a group of straight lines forming an angle of Θ with the light incident surface)
L L L R L L L R
のピッチ)を P (1)、Ρ (2)、 · · ·Ρ (η)、として表すと、全ての Ρは等間隔であり、全  P) is expressed as P (1), Ρ (2), ... · (η), all Ρ are equally spaced,
R R R し  R R R
ての Ρは等間隔であり、かつ Ρと Ρの値は等しい。図 10において、 m番目のピッチ All Ρ are equally spaced, and Ρ and Ρ are equal. In Fig. 10, mth pitch
R L R R L R
と、 n番目のピッチ力も形成される偏向パターン素子を P (m, n)として表現すると、 P ( m, n)は、 mと nがいくつであっても菱形形状となる。  If the deflection pattern element that also forms the nth pitch force is expressed as P (m, n), P (m, n) has a rhombus shape regardless of the number of m and n.
[0053] 第 1の実施態様においては、隣接する偏向パターン素子 17間の間隔 (後述する図 12の Ps)は一定である。 Psの値としては、 30〜500 m力 S好ましく、 100〜200 /ζ πι 力 Sさらに好ましぐ 120〜160 /ζ πιが特に好ましい。なお、導光板 1の出射面 3と反射 面 4の距離 a (導光板の厚み) ίま、 0. 3〜3. Omm力 S好ましく、 0. 35〜0. 8mm力 Sより 好ましく、 0. 4〜0. 8mm力特に好まし!/ヽ。  In the first embodiment, the interval between adjacent deflection pattern elements 17 (Ps in FIG. 12 described later) is constant. The value of Ps is preferably 30 to 500 m force S, more preferably 100 to 200 / ζ πι force S, and further preferably 120 to 160 / ζ πι. Note that the distance a between the exit surface 3 and the reflection surface 4 of the light guide plate 1 a (thickness of the light guide plate) is preferably 0.3 to 3. Omm force S, more preferably 0.35 to 0.8 mm force S, and 0. 4 ~ 0.8mm force especially preferred! / ヽ.
[0054] 図 10において、偏向パターン素子の菱形の辺と y軸とのなす角度(0 及び 0 )は  In FIG. 10, the angles (0 and 0) formed by the rhomboid sides of the deflection pattern element and the y-axis are
L R  L R
、特に制限はないが、光の利用効率の点で 0〜60° 力 S好ましく、 5〜40° がより好ま しぐ 5〜20° が特に好ましい。また、 P 、 Pとしては、金型の加工目の見映えの点  Although there is no particular limitation, 0 to 60 ° force S is preferable in terms of light utilization efficiency, and 5 to 20 ° is more preferable, and 5 to 20 ° is particularly preferable. In addition, as P and P, the appearance of the processing eye of the mold
R L  R L
で 30〜500 /ζ πι力 S好ましく、 100〜200 111カょり好ましく、 120〜160 m力 S特に 好ましい。  30 to 500 / ζ πι force S, preferably 100 to 200 111, more preferably 120 to 160 m force S.
[0055] 図 11は、図 10の XI—XI断面の一部を示す断面図である。同図に示すように、偏向 ノターン素子 17は、光源を向く概四角錐状の反射面である第 1及び第 2面 17a, 17 bと第 3及び第 4面 17c, 17dとを有し、第 1面 17a及び第 2面 17bは、出射面 3と平行 な面に対して、所定の角度 α (傾斜角度)を有する。図 11から明らかなように、第 1 及び第 2面 17a, 17bは、出射面 3と角度 φ 1をなして入射した光を、出射面 3に対し て角度 Φ 2を成す光へ立ち上げる。すなわち、出射面 3の法線に対してある角度をな して入射した光は、第 1及び第 2面 17a, 17bに入射するたびに、前記法線とのなす 角度を減少させることができる。そして、次第に立ち上げられた光は、出射面 3の法線 となす角度が臨界角より小さくなると、出射面 3から出射される。つまり、光源 2から導 光板 1の入射面 5に入射した光は、出射面 3の法線となす角が臨界角に達するまで は出射面 3と反射面 4で全反射を繰り返しながら導光板 1の内部を進む。 [0056] 上記第 1及び第 2面 17a, 17bと出射面 3と平行な面のなす角 a 1は、上記第 3面及 び第 4面の傾斜角度 oc 2よりも小さいことが必要であり、その絶対値も小さい方が好ま しい。 α ΐが小さいほど、光は第 1及び第 2面 17a, 17bとの反射により徐々に立ち上 げられ、出射面 3からの出射光の出射角(出射面の法線と出射光とのなす角)は、常 に臨界角とほぼ等しい角度となる。従って、出射面 3から出射される光の方向は整列 される。このような観点から、第 1及び第 2面 17a, 17bと、出射面 3と平行な面のなす 角度 α ΐ (傾斜角度)は、 0. 5〜3度が好ましぐ 1〜2. 5度がさらに好ましい。 FIG. 11 is a cross-sectional view showing a part of the XI-XI cross section of FIG. As shown in the figure, the deflection pattern element 17 has first and second surfaces 17a and 17b and third and fourth surfaces 17c and 17d, which are substantially quadrangular pyramidal reflecting surfaces facing the light source, The first surface 17a and the second surface 17b have a predetermined angle α (inclination angle) with respect to a surface parallel to the emission surface 3. As is clear from FIG. 11, the first and second surfaces 17a and 17b raise light incident at an angle φ 1 with respect to the emission surface 3 into light having an angle Φ 2 with respect to the emission surface 3. That is, each time the light incident at an angle with respect to the normal of the exit surface 3 enters the first and second surfaces 17a and 17b, the angle formed with the normal can be reduced. . The gradually raised light is emitted from the emission surface 3 when the angle formed with the normal line of the emission surface 3 is smaller than the critical angle. That is, the light incident on the incident surface 5 of the light guide plate 1 from the light source 2 repeats total reflection at the output surface 3 and the reflection surface 4 until the angle formed with the normal line of the output surface 3 reaches a critical angle, while the light guide plate 1 Go inside. [0056] The angle a1 formed by the first and second surfaces 17a, 17b and the surface parallel to the emission surface 3 needs to be smaller than the inclination angle oc2 of the third surface and the fourth surface. The smaller the absolute value, the better. As αΐ is smaller, the light gradually rises due to reflection from the first and second surfaces 17a and 17b, and the exit angle of the exit light from the exit surface 3 (the normal between the exit surface and the exit light). Is always almost equal to the critical angle. Therefore, the directions of light emitted from the emission surface 3 are aligned. From this point of view, the angle αΐ (inclination angle) between the first and second surfaces 17a, 17b and the plane parallel to the exit surface 3 is preferably 0.5 to 3 degrees. The degree is more preferable.
[0057] なお、第 3及び第 4面 17c, 17dと、出射面 3と平行な面のなす角(第 3面及び第 4面 の傾斜角度) α 2は、前記反射作用をほとんど又は全く有さなくするためには、出来る だけ大きい方が好ましい。しかし、後述する導光板 1を成形する際の型抜きを容易に する点からは、 90度以下が好ましい。以上のバランスをとる上では、《2は50〜90度 が好ましぐ 55〜87度がさらに好ましい。  [0057] Note that the angle between the third and fourth surfaces 17c, 17d and the plane parallel to the exit surface 3 (inclination angle between the third surface and the fourth surface) α2 has little or no reflection effect. In order to avoid this, it is preferable to make it as large as possible. However, 90 degrees or less is preferable from the viewpoint of facilitating die cutting when the light guide plate 1 described later is formed. In order to achieve the above balance, << 2 is preferably 50 to 90 degrees, more preferably 55 to 87 degrees.
[0058] また、第 1の実施態様においては、隣接する偏向パターン素子 17間の間隔 Psは、 図 12に示すように一定である。 Psの値としては、 30〜500 111カ 子ましく、 100〜20 0 mがさらに好ましぐ 120〜160 /ζ πιが特に好ましい。なお、導光板 1の出射面 3 と反射面 4の距離 a (導光板の厚み)は、 0. 3〜3. Ommが好ましぐ 0. 35-0. 8m mがより好ましぐ 0. 4〜0. 8mmが特に好ましい。  In the first embodiment, the interval Ps between the adjacent deflection pattern elements 17 is constant as shown in FIG. The value of Ps is particularly preferably 120 to 160 / ζ πι, more preferably 30 to 500 111, more preferably 100 to 200 m. The distance a (light guide plate thickness) between the exit surface 3 and the reflection surface 4 of the light guide plate 1 is preferably 0.3 to 3. Omm, and more preferably 0.35 to 0.8 mm. 4 to 0.8 mm is particularly preferable.
[0059] 次に、底面形状が菱形でない他の実施態様について順次説明する。なお、偏向パ ターンの各面の傾斜角度 α及び α の範囲については、これから説明する本発明の [0059] Next, other embodiments in which the bottom surface shape is not a rhombus will be sequentially described. Note that the ranges of the inclination angles α and α of each surface of the deflection pattern are as follows.
1 2  1 2
他の実施態様においても同様である。  The same applies to other embodiments.
[0060] (第 2の実施態様)  [0060] (Second Embodiment)
第 1の実施態様のように、図 12における前記間隔 (ピッチ) Psが一定であると、液晶 表示素子画素間隔によっては、液晶表示素子のセル配置と導光板の干渉によって、 モアレ(干渉縞)が現れることがある。このような場合、前記間隔 Psを意図的にランダ ムに設定することでモアレを解消又は低減することができる。  When the interval (pitch) Ps in FIG. 12 is constant as in the first embodiment, depending on the liquid crystal display element pixel interval, moire (interference fringes) may occur due to the cell arrangement of the liquid crystal display element and the interference of the light guide plate. May appear. In such a case, moire can be eliminated or reduced by intentionally setting the interval Ps to random.
[0061] Psをランダムにする方法を図 13に示す。図 13は、 Psがランダムになるように加工し た導光板 1を反射面 4側力 見た平面図である。図 13において、導光板 1の左側ピッ チ P ( 1)、P (2)、 · ' · Ρ (m)、導光板 1の右側ピッチ Ρ ( 1)、Ρ (2)、 · ' · Ρ (η)、と して表すと、全ての P、Pはランダムに設定されている。 FIG. 13 shows a method for making Ps random. FIG. 13 is a plan view of the light guide plate 1 that has been processed so that Ps is random and the reflection surface 4 side force is seen. In FIG. 13, the left-side pitches of the light guide plate 1 P (1), P (2), '· Ρ (m), the right-side pitch of the light guide plate 1 Ρ (1), Ρ (2), ·' · Ρ ( η), and In this case, all P and P are set at random.
L R  L R
[0062] P、 Pの中間値 (最大の値と最小の値の中間値)としては、金型加工目の見栄えの  [0062] The intermediate value between P and P (the intermediate value between the maximum and minimum values)
R L  R L
^;で 30〜500 /ζ πι力 S女子ましく、 100〜200 111カ0り女子ましく、 120〜160 m力 S特 に好ましい。また、乱数の範囲としては、上記中間値の ± 15%又は ± 20 /ζ πι以内と することが好ましい。また、偏向パターン素子の四角形の辺と y軸とのなす角度は、特 に制限はないが、光の利用効率の点で 0〜60° 力 子ましく、 5〜40° 力 り好ましく 、 5〜20° が特に好ましい。  ^; 30-500 / ζ πιForce S Women's, 100-200 111 Women's, 120-160 m Force S, especially preferred. The range of random numbers is preferably within ± 15% of the above intermediate value or within ± 20 / ζπι. In addition, the angle formed between the square side of the deflection pattern element and the y-axis is not particularly limited, but it is preferably 0 to 60 ° or more preferably 5 to 40 ° in terms of light utilization efficiency. ˜20 ° is particularly preferred.
[0063] P、 Pの値はランダムに決められている力 P (1) =P (1)、 P (2) =P (2)、 P ( [0063] The values of P and P are randomly determined forces P (1) = P (1), P (2) = P (2), P (
L R L R L R L  L R L R L R L
n) =P (n)となるようにしてもよい。このようにすれば、導光板を加工するときに、一度 n) = P (n). In this way, when processing the light guide plate, once
R R
乱数を決定するだけすむ点で好ましい。このようにして P、 Pの値を決定した導光板  This is preferable in that it only requires determination of a random number. Light guide plate with P and P values determined in this way
L R  L R
の表面形状は、図 14 (a)に示されるように、偏向パターン素子 P (m, n)の形状は、 m =nとなる部分では菱形となり、その稜線は直線上に整列する力 m≠nの部分では 、菱形にならず平行四辺形となり、その稜線も直線上に整列しない。  As shown in Fig. 14 (a), the surface shape of the deflection pattern element P (m, n) is a rhombus in the part where m = n, and its ridgeline is a force that aligns on a straight line m ≠ In the portion of n, it is not a rhombus but a parallelogram, and its ridgeline is not aligned on a straight line.
[0064] 例えば、平行四辺形の辺が y軸となす角度を 10° 、 P、 Pの中間値を 140 /ζ πι、 [0064] For example, the angle between the sides of the parallelogram and the y-axis is 10 °, the intermediate value of P and P is 140 / ζ πι,
R L  R L
乱数の範囲を ± 20 mとした場合、図 14 (b)に示すように、一つ一つの偏向パター ン素子形状は、 y軸方向にが 236〜316 m、 x軸方向に 41〜56 m、また、稜線 の角度 Φは X軸から ± 39. 01° の範囲となる。この稜線の角度は ±40° 以内の範 囲が好ましい。このように、一つ一つの偏向パターン素子形状が豊富なランダム性を もっため、モアレを解消又は低減できるものと予想される。  When the range of random numbers is ± 20 m, as shown in Fig. 14 (b), the shape of each deflection pattern element is 236 to 316 m in the y-axis direction and 41 to 56 m in the x-axis direction. In addition, the angle Φ of the ridgeline is in the range of ± 39.01 ° from the X axis. The angle of this ridge is preferably within ± 40 °. In this way, it is expected that moire can be eliminated or reduced because each deflection pattern element shape has abundant randomness.
[0065] 通常、このような光学部材において、表面形状にランダム性を持たせると、出射光も ランダム性を有するため、集光性能が低下し、結果として光量が低下するという問題 があった。しかし、本実施態様においては、偏向パターン素子 17の稜線 18方向(図 14 (a)の矢印)が全体としては y軸方向に向いているため、ランダム性を有しながらも 、光魏めることが可能となる。なお、もちろん、上記 P、 Pを、完全にランダムとして [0065] Normally, in such an optical member, if the surface shape is made random, the emitted light also has randomness, so that there is a problem that the light collecting performance is lowered and the light quantity is consequently reduced. However, in this embodiment, the direction of the ridge line 18 of the deflection pattern element 17 (the arrow in FIG. 14 (a)) is oriented in the y-axis direction as a whole. It becomes possible. Of course, the above P and P are completely random
L R  L R
何ら相関がな 、ようにしてもかまわな 、。  It doesn't matter what the correlation is.
[0066] (第 3の実施形態) [0066] (Third embodiment)
上記第 1及び第 2の実施態様においては、偏向パターン素子の四角錐の底面の平 行四辺形 (又は菱形)は、四辺のそれぞれが、隣接する平行四辺形の一辺と直線を 形成している。し力しながら、本発明の導光板は、図 7 (a)に示される偏向パターン素 子が多数配列することが一つの特徴であり、これにより、光の利用効率が高ぐ高輝 度なバックライト装置を提供しうる導光板を得ることができるものであるから、必ずしも 上記のように配列する必要はない。つまり、平行四辺形を少し「ずらして」、図 15に示 すように、平行四辺形又は菱形力 四辺のうち一糸且の平行な二辺だけが、隣接する 平行四辺形の一辺と直線を形成してなるようにしてもよい。このような形態は、第 1及 び第 2の実施形態と比較して製造が困難であるが、一方で「ずらし」により偏向パター ン素子の配列にランダム性を与え、見栄え改善やモアレ解消等の効果を得ることも可 能である。 In the first and second embodiments described above, the parallelogram (or rhombus) on the bottom of the quadrangular pyramid of the deflection pattern element is such that each of the four sides forms a straight line with one side of the adjacent parallelogram. Forming. However, one feature of the light guide plate of the present invention is that a large number of deflection pattern elements shown in FIG. 7 (a) are arranged. Since a light guide plate capable of providing a light device can be obtained, it is not always necessary to arrange as described above. In other words, by slightly shifting the parallelogram, as shown in Fig. 15, only two parallel sides of one side of the parallelogram or rhomboid force form a straight line with one side of the adjacent parallelogram. You may make it become. Such a form is difficult to manufacture as compared to the first and second embodiments, but on the other hand, “shift” gives randomness to the arrangement of the deflection pattern elements, improves appearance, eliminates moire, etc. It is also possible to obtain the effect.
[0067] (第 4の実施態様)  [0067] (Fourth embodiment)
上記第 1及び第 2の実施態様においては、光源付近の暗部を解消するために、偏 向パターン素子を平行四辺形又は菱形とした。しかし、 LEDの数が多力つたり、線状 光源を使用したり、液晶表示装置の構造上、暗部が見えないような場合は、偏向バタ ーン素子を平行四辺形又は菱形とする必要がない場合もある。この場合、図 16 (a) や図 16 (b)のように、反射溝自体は X軸又は y軸に平行な方向の直線である力 その 間隔がランダムである導光板としてもょ 、。  In the first and second embodiments, in order to eliminate the dark part near the light source, the polarization pattern element is a parallelogram or rhombus. However, if the number of LEDs is numerous, a linear light source is used, or the dark part is not visible due to the structure of the liquid crystal display device, the deflection pattern element must be a parallelogram or rhombus. There may be no. In this case, as shown in FIG. 16 (a) and FIG. 16 (b), the reflecting groove itself is a force that is a straight line in a direction parallel to the X axis or the y axis.
[0068] (出射面への加工)  [0068] (Processing on the exit surface)
出射面 3には、異方性を有する異方性拡散パターンが形成されていることが好まし ぐこの異方性拡散パターンは、光拡散特性が入射面と平行方向に 30〜70度の半 値角であり、直交する方向に 0. 5〜3度の半値角で異形拡散するものであることがよ り好ましい。  It is preferable that an anisotropic diffusion pattern having anisotropy is formed on the exit surface 3. This anisotropic diffusion pattern has a light diffusion characteristic of half of 30 to 70 degrees in a direction parallel to the incident surface. More preferably, it is a value angle, and is irregularly diffused at a half-value angle of 0.5 to 3 degrees in the orthogonal direction.
[0069] また、前記異方性拡散パターンとしてホログラムが形成されて 、ることが好ましく、こ のホログラムはサーフェスレリーフホログラムであることが特に好ましい(3次元的に形 成されたホログラムと区別するためにサーフェスレリーフホログラムと称される)。こうす ることで入射面と直交する方向に長 、線状の複数のランダムスペックル領域を有する  [0069] Further, it is preferable that a hologram is formed as the anisotropic diffusion pattern, and it is particularly preferable that this hologram is a surface relief hologram (in order to distinguish it from a three-dimensionally formed hologram). Called surface relief hologram). In this way, it has a plurality of long and linear random speckle regions in a direction perpendicular to the incident surface.
[0070] (バックライト装置) [0070] (Backlight device)
本発明の導光板を使用したバックライト装置としては、すでに説明した図 6のように 配置してもよぐまた図 17に示すように、導光板の偏向パターン素子 17が出射面 3に 設けられていてもよい。このようにすると、第 1の実施形態のように偏向パターン素子 1 7を反射面 4に設けた導光板と比較して、光源 2付近の見栄えがよくなる傾向があり、 輝度も向上する傾向があるため好まし 、。 The backlight device using the light guide plate of the present invention is as shown in FIG. Alternatively, as shown in FIG. 17, the deflection pattern element 17 of the light guide plate may be provided on the exit surface 3. In this way, as compared with the light guide plate in which the deflection pattern element 17 is provided on the reflection surface 4 as in the first embodiment, the appearance near the light source 2 tends to be improved, and the luminance tends to be improved. Because, preferred.
[0071] 第 1の実施形態のように偏向パターン素子 17を反射面 4側に設ける力、第 4の実施 形態のように偏向パターン素子 17を出射面 3側に設けるかは、用途によって自由に 選択することができる。例えば、偏向パターン素子 17を出射面 3側に設けると、光源 2 付近の見栄えがよくなる反面、使用するプリズムシート 6によっては、プリズムシート 6 と導光板 1との間に水泡のような模様が観察されてしまう場合がある。一方で第 1の実 施形態であると、輝度や見栄えが第 4の実施形態と比較して若干劣る反面、出射面 に偏向パターン素子 17が形成されていないため、出射面に別の加工を施すことがで きる。例えば、出射光のムラを低減したり、モアレを低減したりするために出射面に粗 面加工を施すことができる。もちろん第 4の実施形態においても同様の粗面加工を行 うことができるが、粗面は観察者力 より遠い位置に配置されることとなるため、第 1の 実施形態と比較して、効果が劣る。  Whether the deflection pattern element 17 is provided on the reflection surface 4 side as in the first embodiment, or whether the deflection pattern element 17 is provided on the emission surface 3 side as in the fourth embodiment, can be freely selected depending on the application. You can choose. For example, when the deflection pattern element 17 is provided on the exit surface 3 side, the appearance near the light source 2 is improved. On the other hand, depending on the prism sheet 6 used, a pattern like water bubbles is observed between the prism sheet 6 and the light guide plate 1. It may be done. On the other hand, in the first embodiment, the brightness and appearance are slightly inferior to those in the fourth embodiment, but since the deflection pattern element 17 is not formed on the exit surface, another processing is performed on the exit surface. Can be applied. For example, the exit surface can be roughened to reduce the unevenness of the exit light or to reduce moire. Of course, the same rough surface processing can also be performed in the fourth embodiment, but the rough surface is arranged at a position farther than the observer's force, so that the effect is improved as compared with the first embodiment. Is inferior.
[0072] (偏向パターンがない面への加工)  [0072] (Processing with no deflection pattern)
本発明の導光板において、偏向パターン素子 17が形成されていない面には、異方 性を有する異方性拡散パターンが形成されて 、ることが好ましく、この異方性拡散パ ターンは、光拡散特性が入射面と平行方向に 30〜70度の半値角であり、直交する 方向に 0. 5〜3度の半値角で異形拡散するものであることがより好ましい。  In the light guide plate of the present invention, it is preferable that an anisotropic diffusion pattern having anisotropy is formed on the surface where the deflection pattern element 17 is not formed. More preferably, the diffusion characteristic is a half-value angle of 30 to 70 degrees in the direction parallel to the incident surface, and an irregular diffusion with a half-value angle of 0.5 to 3 degrees in the orthogonal direction.
[0073] また、前記異方性拡散パターンとしてホログラムが形成されて 、ることが好ましく、こ のホログラムはサーフェスレリーフホログラムであることが特に好ましい(3次元的に形 成されたホログラムと区別するためにサーフェスレリーフホログラムと称される)。こうす ることで入射面と直交する方向に長 、線状の複数のランダムスペックル領域を有する  [0073] Further, it is preferable that a hologram is formed as the anisotropic diffusion pattern, and it is particularly preferable that this hologram is a surface relief hologram (in order to distinguish it from a three-dimensionally formed hologram). Called surface relief hologram). In this way, it has a plurality of long and linear random speckle regions in a direction perpendicular to the incident surface.
[0074] 図 18及び図 19は、出射面 3に形成されたホログラム 100の詳細を示す拡大図であ る.図 18はホログラムを 200倍に拡大した拡大図であり、図 19はホログラムをさらに 拡大した拡大図である。 [0075] 図 18に示すように、ホログラムは、 200倍程度に拡大して見た場合、入射面 4に直 交する方向に伸びる線状の多数のランダムスペックル又はランダムスペックル領域( 例えば他の領域に比べて透過率が高い (又は低い)領域)(ランダムな溝或いは凹凸 ) 100aを有する。このランダムスペックル 100aは、その形状及び位置がホログラム全 体において一定で無ぐランダム性を有する。 18 and 19 are enlarged views showing details of the hologram 100 formed on the exit surface 3. FIG. 18 is an enlarged view of the hologram enlarged 200 times, and FIG. It is an enlarged view. [0075] As shown in FIG. 18, when the hologram is magnified to about 200 times, a large number of linear random speckles or random speckle regions extending in a direction perpendicular to the incident surface 4 (for example, other speckle regions) (Region having higher (or lower) transmittance) than the region (random grooves or irregularities) 100a. The random speckle 100a has a random shape and a position that is not constant throughout the hologram.
[0076] 後述するように、線状スペックル 100aにより、ホログラムに入射した光は入射面 5と 平行な方向に強く拡散され直交方向は弱い拡散特性となる。入射面 5と平行方向と 直交方向の拡散度の拡散比は、スペックルの長軸及び短軸の寸法によって決定され る。  [0076] As will be described later, the linear speckle 100a causes the light incident on the hologram to be diffused strongly in the direction parallel to the incident surface 5 and weak in the orthogonal direction. The diffusion ratio of the diffusivity in the direction parallel to and perpendicular to the incident surface 5 is determined by the major and minor axis dimensions of the speckle.
[0077] また、スペックル 100aのランダム性により、ホログラムへの入射光は、ランダムな方 向へ散乱或いは透過される。従って、ホログラムはディフューザとしての機能を有する  [0077] Further, due to the randomness of the speckle 100a, the incident light to the hologram is scattered or transmitted in a random direction. Therefore, the hologram has a function as a diffuser.
[0078] 図 20は、ホログラムの作用を説明する図である。 FIG. 20 is a diagram for explaining the operation of the hologram.
[0079] 図 20 (a)は、導光板 1の出射面 3の点 Pl、 P2から出射された光の強度の角度依存 性を示す上面図である。図 20 (b)は、導光板 1の出射面 3の点 P2から出射された光 の強度分布を立体的に示す斜視図である。  FIG. 20 (a) is a top view showing the angle dependence of the intensity of the light emitted from the points Pl and P2 on the exit surface 3 of the light guide plate 1. FIG. FIG. 20 (b) is a perspective view showing a three-dimensional intensity distribution of light emitted from the point P2 on the exit surface 3 of the light guide plate 1. FIG.
[0080] 導光板 1の出射面 3の点 PI, P2,力 出射された光は、出射面 3に形成されたホロ グラム 100によって、楕円 El, E2に示すように前記入射面 5と平行な方向に強く拡 散され直交方向は弱い拡散特性となる。 [0080] Points PI, P2, force on the exit surface 3 of the light guide plate 1 The emitted light is parallel to the entrance surface 5 as shown by ellipses El, E2 by the hologram 100 formed on the exit surface 3. The diffusion is strong in the direction and weak in the orthogonal direction.
[0081] 図 21は、前記出射光の強度分布を示す。図 21 (a)は前記 Θ方向における前記出 射光の強度分布を示し、図 21 (b)は前記 r方向における前記出射光の強度分布を示 す。 FIG. 21 shows the intensity distribution of the emitted light. FIG. 21 (a) shows the intensity distribution of the emitted light in the Θ direction, and FIG. 21 (b) shows the intensity distribution of the emitted light in the r direction.
[0082] 上記したように、入射面 5と直交方向 rと比較して平行方向 Θに強く拡散され、 Θ方 向に於ける拡散角 Φ の半値幅 Φ は、 r方向に於ける拡散角 Φの半値幅 Φ よりも  [0082] As described above, the half-width Φ of the diffusion angle Φ in the Θ direction is strongly diffused in the parallel direction Θ compared to the incident surface 5 and the orthogonal direction r, and the diffusion angle Φ in the r direction Than half width of Φ
θ Θ 0 r rO 十分に大きい(Φ > > Φ ;)。  θ Θ 0 r rO is sufficiently large (Φ >> Φ;).
Θ 0 rO  Θ 0 rO
[0083] 前記 r方向の半値幅 Φ は、 0. 5< Φ ≤3度が好ましぐ 1 < Φ ≤2度が更に好ま  [0083] The half-value width Φ in the r direction is preferably 0.5 <Φ ≤3 degrees, more preferably 1 <Φ ≤2 degrees.
rO rO rO  rO rO rO
しい。一方、 Θ方向の半値幅 Φ は、 30〜70度が好ましぐ 45〜65度が更に好まし  That's right. On the other hand, the half-width Φ in the Θ direction is preferably 30 to 70 degrees, more preferably 45 to 65 degrees.
Θ 0  Θ 0
く、 50〜60度が更に好ましい。 [0084] 前記ホログラムの異方性拡散作用により、この導光板 1においては、 0方向におけ る一様な出射光の強度分布が実現される。就中、出射面 3からの出射光における輝 線の出現が防止される。 50 to 60 degrees is more preferable. Due to the anisotropic diffusion action of the hologram, a uniform intensity distribution of the emitted light in the 0 direction is realized in the light guide plate 1. In particular, the appearance of bright lines in the light emitted from the exit surface 3 is prevented.
[0085] (光学シート)  [0085] (Optical sheet)
図 22は、導光板及び光学シートを有するバックライト装置 (又は面光源装置)の一 部を示す図である。導光板 1及び光学シート(プリズムフィルム) 10を有するバックライ ト装置において、導光板 1の出射面 3から出射された光は、出射面 3となす角度 γ 1, γ 2が小さい成分の光 L , Lを含んでいる。光学シート 10は、平坦な上面(10A)と  FIG. 22 is a diagram showing a part of a backlight device (or a surface light source device) having a light guide plate and an optical sheet. In the backlight apparatus having the light guide plate 1 and the optical sheet (prism film) 10, the light emitted from the light exit surface 3 of the light guide plate 1 is light L having components with small angles γ1, γ2 formed by the light exit surface 3. Contains L. The optical sheet 10 has a flat upper surface (10A)
1 2  1 2
プリズム状の下面(10B)を有し、導光板 1の出射面 3となす角度が小さい光 L , Lが  Light L, L, which has a prism-shaped lower surface (10B) and has a small angle with the light exit surface 3 of the light guide plate 1,
1 2 下面(10B)力 入射されると、上面(10A)と大きな角度をなすように偏向して出射す る(L L ')。このように、光学シート 10は、液晶表示装置に出射される光の正面強 1 2 Lower surface (10B) force When incident, it deflects and emits at a large angle with the upper surface (10A) (L L '). As described above, the optical sheet 10 has the front intensity of the light emitted to the liquid crystal display device.
1 2 1 2
度を向上させる。  Improve the degree.
[0086] このような光学シートとしては、一般プリズム構造であれば特に制限はなぐ具体的 には例えば、 M065HS (三菱レイヨン)、 M168YS (三菱レイヨン)、 Τ—ΒΕΜ (3Μ) 等を挙げることができ、これらは単数で又は 2種類以上若しくは 2枚以上を組み合わ せて使用することができる。  [0086] Specific examples of such an optical sheet are not particularly limited as long as they have a general prism structure. Examples thereof include M065HS (Mitsubishi Rayon), M168YS (Mitsubishi Rayon), and Τ-ΒΕΜ (3Μ). These can be used singly or in combination of two or more or two or more.
[0087] 前記バックライト装置 (又は面光源装置)は、携帯電話 ·電子手帳等の液晶表示装 置に於いて、バックライトとして使用することが出来る。  The backlight device (or surface light source device) can be used as a backlight in a liquid crystal display device such as a mobile phone or an electronic notebook.
[0088] なお、上述の実施の形態は、本発明の一具体例を示すものであり、本発明はこれ に限定されない。本発明の範囲を逸脱しない限り、種々の対象に適用することができ る。また、実施例中に示した数値は、一例に過ぎず、本発明がこれに限定されないこ とはいうまでもない。  Note that the above-described embodiment shows a specific example of the present invention, and the present invention is not limited to this. The present invention can be applied to various objects without departing from the scope of the present invention. Further, the numerical values shown in the examples are merely examples, and it goes without saying that the present invention is not limited thereto.
[0089] 例えば、前記光源は、実質的に点光源であればよぐ 1チップ LEDでも、 2チップ L EDでも、多チップ LEDでもよい。  [0089] For example, the light source may be a single-chip LED, a 2-chip LED, or a multi-chip LED as long as it is a point light source.

Claims

請求の範囲  The scope of the claims
[I] 側面に入射面を有し、上面又は下面に出射面を有する板状の導光板であって、 前記出射面又は前記出射面と対向する面に、複数の偏向パターン素子が配列して おり、  [I] A plate-shaped light guide plate having an incident surface on a side surface and an output surface on an upper surface or a lower surface, wherein a plurality of deflection pattern elements are arranged on the output surface or the surface facing the output surface. And
該偏向パターン素子は、四角錐の底面以外の 4つの面が、導光板に一体形成され た四角錐形状を有してなり、  The deflection pattern element has a quadrangular pyramid shape in which four surfaces other than the bottom surface of the quadrangular pyramid are integrally formed on the light guide plate.
前記 4つの面のうち、隣接する第 1面と第 2面のそれぞれの面積は、隣接する第 3面 と第 4面のそれぞれの面積の 10倍以上であり、  Of the four surfaces, the area of each of the adjacent first surface and the second surface is at least 10 times the area of each of the adjacent third surface and the fourth surface,
前記第 1面及び前記第 2面のそれぞれの傾斜角は、前記第 3面及び第 4面のそれ ぞれの傾斜角より小さい導光板。  The light guide plate having an inclination angle of each of the first surface and the second surface being smaller than an inclination angle of each of the third surface and the fourth surface.
[2] 前記パターン素子は、四角錐形状が導光板に凹設 (d印 ressed)されてなる請求項 1 記載の導光板。 2. The light guide plate according to claim 1, wherein the pattern element has a quadrangular pyramid shape that is recessed (d-ressed) in the light guide plate.
[3] 概四角錐の偏向パターン素子のピッチ Pが一定である請求項 1記載の導光板。  [3] The light guide plate according to [1], wherein the pitch P of the deflection pattern elements having a substantially quadrangular pyramid is constant.
s  s
[4] 概四角錐の偏向パターン素子のピッチ Pが不定である請求項 1記載の導光板。  [4] The light guide plate according to [1], wherein the pitch P of the deflection pattern elements of the substantially quadrangular pyramid is indefinite.
s  s
[5] 前記第 1面及び前記第 2面のそれぞれの傾斜角は、前記出射面に対して 0. 5〜3 [5] The inclination angles of the first surface and the second surface are 0.5 to 3 with respect to the exit surface.
° である請求項 1記載の導光板。 The light guide plate according to claim 1, wherein the light guide plate is.
[6] 前記パターン素子は、四角錐形状の底面が平行四辺形である請求項 1記載の導 光板。 6. The light guide plate according to claim 1, wherein the pattern element has a quadrangular pyramid bottom surface that is a parallelogram.
[7] 前記平行四辺形の辺が入射面となす角 0 及び 0 は、それぞれ 0を超え 60° 以  [7] The angles 0 and 0 between the sides of the parallelogram and the incident surface are each greater than 0 and less than 60 °
R L  R L
下である請求項 6記載の導光板。  The light guide plate according to claim 6, which is below.
[8] 前記 0 と前記 0 は同じ角度である請求項 7記載の導光板。 8. The light guide plate according to claim 7, wherein the 0 and the 0 are the same angle.
L R  L R
[9] 前記平行四辺形は、四辺のうち一組の平行な二辺が、隣接する平行四辺形の一 辺と直線を形成してなる請求項 6記載の導光板。  9. The light guide plate according to claim 6, wherein the parallelogram has a set of two parallel sides out of the four sides that forms a straight line with one side of the adjacent parallelogram.
[10] 前記平行四辺形は、四辺のそれぞれが、隣接する平行四辺形の一辺と直線を形 成してなる請求項 6記載の導光板。 10. The light guide plate according to claim 6, wherein each of the four sides of the parallelogram forms a straight line with one side of the adjacent parallelogram.
[II] 請求項 10記載の導光板において、  [II] The light guide plate according to claim 10,
入光面と Θ  Incident surface and Θ
しの角をなす直線群のピッチを、入光面側から順に P (1)、 P (2)、 · · ·  P (1), P (2), in order from the light incident surface side.
し し  Lion
P (m)と表し、 入光面と Θ の角をなす直線群のピッチを、入光面側から順に P (1)、 P (2)、 · · ·P (m) P (1), P (2), etc. in order from the light incident surface side, the pitch of the straight line group that forms an angle of Θ with the light incident surface
R R R R R R
P (n)、として表したとき、  When expressed as P (n),
R  R
P (m)及び P (n)が全て同じ値である導光板。  A light guide plate in which P (m) and P (n) all have the same value.
L R  L R
[12] 請求項 10記載の導光板において、  [12] The light guide plate according to claim 10,
入光面と Θ の角をなす直線群のピッチを、入光面側から順に P (1)、 P (2)、 · · ·  P (1), P (2), etc. in order from the light incident surface side, the pitch of the straight lines forming the angle of Θ with the light incident surface
し し し  し し し し
P (m)と表し、  P (m)
 Shi
入光面と Θ の角をなす直線群のピッチを、入光面側から順に P (1)、 P (2)、 · · ·  P (1), P (2), etc. in order from the light incident surface side, the pitch of the straight line group that forms an angle of Θ with the light incident surface
R R R  R R R
P (n)、として表したとき、  When expressed as P (n),
R  R
P (m)及び P (n)がの数値は、乱数で設定されてなる導光板。  The light guide plate in which P (m) and P (n) are set with random numbers.
L R  L R
[13] 前記 P及び前記 P力 P (1) =P (1)、P (2) =P (2)、 · ' ·Ρ (η) =Ρ (η)の関  [13] The relationship between P and P force P (1) = P (1), P (2) = P (2), · '· Ρ (η) = Ρ (η)
L R L R L R L R  L R L R L R L R
係を満たす請求項 12記載の導光板。  The light guide plate according to claim 12, wherein the light guide plate satisfies a relationship.
[14] 前記 P及び前記 Pの中間値は、それぞれ 30〜500 mである請求項 13記載の [14] The intermediate value of the P and the P is 30 to 500 m, respectively.
L R  L R
導光板。  Light guide plate.
[15] 前記乱数の範囲は、前記中間値 ± 15%又は ± 20 mである請求項 12記載の導 光板。  15. The light guide plate according to claim 12, wherein the range of the random number is the intermediate value ± 15% or ± 20 m.
[16] 前記第 1面及び前記第 2面から形成される稜線と、前記入射面の法線のなす角が  [16] An angle formed by a ridge line formed from the first surface and the second surface and a normal line of the incident surface is
±40° 以内である請求項 12記載の導光板。  13. The light guide plate according to claim 12, which is within ± 40 °.
[17] 前記偏向パターン素子が前記出射面と対向する面に形成され、出射面には他の光 学素子が形成されてなる請求項 1記載の導光板。 17. The light guide plate according to claim 1, wherein the deflection pattern element is formed on a surface facing the emission surface, and another optical element is formed on the emission surface.
[18] 前記他の光学素子が、出射光の拡散又は集光する機能を有する光学素子である 請求項 17記載の導光板。 18. The light guide plate according to claim 17, wherein the other optical element is an optical element having a function of diffusing or condensing outgoing light.
[19] 前記他の光学素子が、異方拡散性を有してなる請求項 17記載の導光板。 19. The light guide plate according to claim 17, wherein the other optical element has anisotropic diffusivity.
[20] 請求項 1〜19のいずれかに記載の導光板を備えるバックライト装置。 [20] A backlight device comprising the light guide plate according to any one of claims 1 to 19.
[21] 側面に入射面を有し、上面又は下面に出射面を有する板状の導光板にして、前記 出射面と対向する面に導光板の一般肉厚に対し、減ずる方向に形成された概略四 角錐の偏向パターン素子が隣接し配列しており、その四角錐の形状は、四角錐の底 面以外の 4面が導光板に一体形成されたものであって、 [21] A plate-shaped light guide plate having an entrance surface on a side surface and an exit surface on an upper surface or a lower surface, and formed on a surface facing the exit surface in a direction to reduce the general thickness of the light guide plate The quadrangular pyramid deflection pattern elements are arranged adjacent to each other, and the shape of the quadrangular pyramid is such that four surfaces other than the bottom surface of the quadrangular pyramid are integrally formed on the light guide plate.
底面以外の 4面のうち、第 1及び第 2の面は、それぞれ他の第 3又は第 4の面の面 積の 20倍以上あり、 Of the four surfaces other than the bottom surface, the first and second surfaces are the surfaces of the other third or fourth surface, respectively. More than 20 times the product,
前記第 1及び第 2の面の稜線が入射面と直交し、  The ridgelines of the first and second surfaces are orthogonal to the entrance surface;
前記第 1及び第 2の面の前記出射面に対する傾斜角は 0. 5〜3度の範囲であり、 前記第 1及び第 2の面は概同面積であり、  An inclination angle of the first and second surfaces with respect to the emission surface is in a range of 0.5 to 3 degrees, and the first and second surfaces are approximately the same area,
前記第 3及び第 4の面は概同面積である  The third and fourth surfaces are approximately the same area.
ことを特徴とする導光板。  A light guide plate characterized by that.
[22] 出射面側にサーフェスレリーフホログラムを一体的に成形したことを特徴とした請求 項 21に記載の導光板。 22. The light guide plate according to claim 21, wherein a surface relief hologram is integrally formed on the exit surface side.
[23] 概四角錐の偏向パターン素子のピッチが一定である請求項 21または請求項 22に 記載の導光板。  23. The light guide plate according to claim 21 or claim 22, wherein the pitch of the substantially square pyramid deflection pattern elements is constant.
[24] 概四角錐の偏向パターン素子のピッチが不定である請求項 21または請求項 22に 記載の導光板。  24. The light guide plate according to claim 21 or claim 22, wherein the pitch of the substantially square pyramid deflection pattern elements is indefinite.
[25] 前記サーフェスレリーフホログラムは、入射面と直交する方向に長!、線状の複数の ランダムスペックル領域を有する請求項 21または請求項 22に記載の導光板。  25. The light guide plate according to claim 21, wherein the surface relief hologram has a plurality of linear random speckle regions that are long in a direction orthogonal to the incident surface.
[26] 前記サーフェスレリーフホログラムの光拡散特性が入射面と平行方向に 30〜70度 の半値角であり、直交する方向に 0. 5〜3度の半値角で異形拡散することを特徴とし た請求項 21または請求項 22に記載の導光板。  [26] The surface relief hologram is characterized in that the light diffusion characteristic is a half-value angle of 30 to 70 degrees in a direction parallel to the incident surface, and an irregular diffusion with a half-value angle of 0.5 to 3 degrees in the orthogonal direction. The light guide plate according to claim 21 or claim 22.
[27] 請求項 21乃至 26のいずれかに記載の導光板を備えるバックライト装置。  27. A backlight device comprising the light guide plate according to any one of claims 21 to 26.
PCT/JP2005/021139 2004-11-19 2005-11-17 Light guide plate WO2006054654A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1876388A1 (en) * 2006-07-04 2008-01-09 Samsung SDI Co., Ltd. Light guide member and backlight unit including light guide member

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JPH1020125A (en) * 1996-06-28 1998-01-23 Nitto Denko Corp Surface light source device and liquid crystal display device
JP2003066235A (en) * 2001-08-27 2003-03-05 Sanyo Electric Co Ltd Light transmission plate and surface light source device using the same
JP2003098356A (en) * 2001-09-20 2003-04-03 Pioneer Electronic Corp Light transmission plate
JP2004111384A (en) * 2002-08-30 2004-04-08 Hitachi Chem Co Ltd Light guide plate and backlight device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1020125A (en) * 1996-06-28 1998-01-23 Nitto Denko Corp Surface light source device and liquid crystal display device
JP2003066235A (en) * 2001-08-27 2003-03-05 Sanyo Electric Co Ltd Light transmission plate and surface light source device using the same
JP2003098356A (en) * 2001-09-20 2003-04-03 Pioneer Electronic Corp Light transmission plate
JP2004111384A (en) * 2002-08-30 2004-04-08 Hitachi Chem Co Ltd Light guide plate and backlight device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1876388A1 (en) * 2006-07-04 2008-01-09 Samsung SDI Co., Ltd. Light guide member and backlight unit including light guide member
US7568827B2 (en) 2006-07-04 2009-08-04 Samsung Mobile Display Co., Ltd. Light guide member and backlight unit including light guide member

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