TW201314314A - Light guide plate, surface light source device, and transmissive image display device - Google Patents

Abstract

A light guide plate (50) is provided with a board-like main body section (51) and a plurality of lens sections (52). The main body section has: a first surface (51a), which extends in one direction, and has formed thereon a plurality of protruding strip-like sections (55) disposed in parallel in the direction substantially orthogonally intersecting the one direction; a second surface (51b) on the reverse side of the first surface; and light input surfaces (51c, 51d), which are surfaces that respectively intersect the first and the second surfaces, and have light inputted thereto. Each of the lens sections is formed on the second surface of the main body section, and is convex to the side opposite to the side having the first surface when viewed from the second surface.

Description

Light guide plate, surface light source device and transmissive image display device

The present invention relates to a light guide plate, a surface light source device, and a transmissive image display device.

The transmissive image display device such as a liquid crystal display device usually includes a surface light source device that is disposed on the back side of the transmissive image display unit such as a liquid crystal display panel and supplies the backlight to the transmissive image display unit. Light source device. As the above-described surface light source device, an edge illumination type surface light source device is known (for example, see Patent Document 1).

The edge illumination type surface light source device includes: a light guide plate having light transmissivity; and a light source disposed on a side of the light guide plate for supplying light to a side surface of the light guide plate. A white point for reflecting light is provided on the back side of the light guide plate. In this configuration, the light output from the light source enters the light guide plate from the side surface of the light guide plate facing the light source, and propagates while being totally reflected inside the light guide plate. Since a plurality of white spots are formed on the back side of the light guide plate (for example, refer to Patent Document 1), the light reflected by the white dots is emitted from the exit surface of the light guide type image display unit side of the light guide plate.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2005-38768

However, in a light guide plate having a white point, sometimes light incident on the light guide plate The light is not sufficiently emitted from the exit surface, and the improvement in brightness cannot be sufficiently achieved.

Accordingly, an object of the present invention is to provide a light guide plate capable of improving brightness and a surface light source device and a transmissive image display device including the above-described light guide plate.

The light guide plate of the present invention comprises a plate-shaped body portion and a plurality of lens portions. The main body portion includes: a first surface extending in one direction, and a plurality of ridge portions arranged side by side in a direction substantially orthogonal to one direction; a second surface opposite to the first surface; and an incident surface The surface is a surface that intersects the first and second faces, and the light is incident. The lens portion is formed on the second surface of the main body portion, and protrudes to the side opposite to the side on which the first surface is located when viewed from the second surface.

A surface light source device according to the present invention includes: the light guide plate; and a light source unit disposed to face the incident surface of the light guide plate and supply light to the incident surface.

Moreover, the transmissive image display device of the present invention includes: the light guide plate; the light source unit disposed to face the incident surface of the light guide plate and supplying light to the incident surface; and the transmissive image display unit provided on The first surface side of the light guide plate is illuminated by light emitted from the light guide plate to display an image.

In the light guide plate, the surface light source device, and the transmissive image display device having the above configuration, the light incident from the incident surface of the light guide plate propagates while being totally reflected in the light guide plate. When the light propagating in the light guide plate is incident on the lens portion provided on the second surface, it is reflected by the lens portion under conditions different from the total reflection condition. Thereby, the light reflected by the lens portion is emitted from the first surface of the body portion. Since the ridge portion is formed on the first surface, the light emission efficiency is increased. By its action, the brightness is increased. Moreover, the transmissive image display of the present invention In the display device, since the transmissive image display portion is provided on the light guide plate, the transmissive image display portion is illuminated by the light having higher brightness. As a result, the brightness of the image displayed by the transmissive image display unit can be improved.

Moreover, in the light guide plate, the surface light source device, and the transmissive image display device of the present invention, the ridge portion formed on the first surface can be a lenticular lens or a ridge.

According to the present invention, a light guide plate capable of improving brightness and a surface light source device and a transmissive image display device including the above-described light guide plate can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and the description thereof will not be repeated. The size ratio of the schema is not necessarily consistent with the stated object. Further, in the description, words such as "upper" and "lower" indicate the convenience based on the state shown in the drawing.

Fig. 1 is a schematic view showing a schematic configuration of a transmissive image display device according to an embodiment of a light guide plate to which the present invention is applied. In FIG. 1, the cross-sectional configuration of the transmissive image display device 10 is shown. The transmissive image display device 10 can be preferably used as a display device or a television device for a mobile phone or various electronic devices.

The transmissive image display device 10 includes a transmissive image display unit 20 and a surface light source device 30 that outputs planar light for supply to the transmissive image display unit 20. Hereinafter, for convenience of explanation, as shown in FIG. 1, the opposite-surface light source device 30 refers to the direction in which the transmissive image display unit 20 is arranged as the Z-axis direction. Or the front direction. Further, two directions orthogonal to the Z-axis direction are referred to as an X-axis direction and a Y-axis direction. The X-axis direction and the Y-axis direction are orthogonal to each other.

The transmissive image display unit 20 displays an image by illuminating the surface light emitted from the surface light source device 30. An example of the transmissive image display unit 20 is a liquid crystal display panel which is a polarizing plate bonding body in which the linear polarizing plates 22 and 23 are disposed on both surfaces of the liquid crystal cell 21. In this case, the transmissive image display device 10 is a liquid crystal display device (or a liquid crystal television). As the liquid crystal cell 21 and the polarizing plates 22 and 23, a user of a transmissive image display device such as a liquid crystal display device of the prior art can be used. The liquid crystal cell 21 is, for example, a TFT (Thin Film Transistor) type liquid crystal cell or an STN (Super Twisted Nematic) type liquid crystal cell.

The surface light source device 30 is a backlight module that supplies an edge illumination type to the backlight of the transmissive image display unit 20. The surface light source device 30 includes a light guide plate 50 and light source portions 60 and 60 that are disposed opposite to the side faces 50a and 50b of the light guide plate 50 facing each other.

The light source units 60 and 60 include a plurality of point light sources 61 arranged in a line (in FIG. 1 and arranged in the Y-axis direction). An example of the point light source 61 is a light emitting diode. The light source unit 60 may include a reflector as a reflection portion for reflecting light on the opposite side of the light guide plate 50 in order to efficiently input light to the light guide plate 50. Here, the light source unit 60 including a plurality of point light sources 61 is exemplified, but the light source unit 60 may be a linear light source such as a CCFL (Cold Cathode Fluorescent Lamp).

The surface light source device 30 may include a reflection portion 70 on the side opposite to the side on which the transmissive image display portion 20 is located with respect to the light guide plate 50. Reflection unit 70 The light emitted from the light guide plate 50 to the side of the reflection portion 70 is incident on the light guide plate 50 again. The reflection portion 70 may also have a sheet shape as shown in FIG. Further, the reflection portion 70 may be a bottom surface of the frame body of the surface light source device 30 that houses the light guide plate 50, and is a bottom surface on which mirror surface processing is performed.

The light guide plate 50 will be described with reference to Figs. Fig. 2 is a plan view showing a state in which the light guide plate 50 shown in Fig. 1 is viewed from the back side. Fig. 3 is a left side view of the light guide plate 50 shown in Fig. 1 as viewed from the left side. The planar shape of the light guide plate 50 includes, for example, a substantially rectangular shape and a substantially square shape.

The light guide plate 50 includes a plate-shaped main body portion 51 having a ridge portion 55 formed on an emission surface (first surface) 51a side of the main body portion 51, and a plurality of lens portions 52 formed on and formed with ridges The surface of the portion 55 is on the opposite side to the side of the back surface (second surface) 51b of the main body portion 51. The body portion 51 includes a light transmissive material (or a transparent material). The refractive index of the light transmissive material is, for example, 1.46 to 1.62. The light transmissive material contains, for example, a translucent resin material or a translucent glass material. Examples of the light transmissive resin material include polycarbonate resin (refractive index: 1.59), MS resin (methyl methacrylate-styrene copolymer resin) (refractive index: 1.56 to 1.59), and polystyrene resin (refractive index) : 1.59), AS resin (acrylonitrile-styrene copolymer resin) (refractive index: 1.56 to 1.59), acrylic ultraviolet curing resin (refractive index: 1.46 to 1.58), polymethyl methacrylate (PMMA, Polymethylmethacrylate) (refractive index: 1.49). The translucent resin material is more preferably PMMA from the viewpoint of transparency.

As shown in FIGS. 1 to 3, the main body portion 51 includes an exit surface 51a that faces the transmissive image display unit 20, a back surface 51b that is opposite to the exit surface 51a, and four intersecting with the exit surface 51a and the back surface 51b. Side faces 51c, 51d, 51e, 51f. In Fig. 1, two side faces 51c and 51d which face each other in the X-axis direction are shown. The side surface 51c and the side surface 51d are also the side surface 50a and the side surface 50b which oppose the light source part 60. In this case, the side surface 51c and the side surface 51d are incident surfaces on which light from the light source unit 60 is incident. The two side faces 51e and 51f (see FIG. 3) remaining in the four side faces 51c, 51d, 51e, and 51f of the main body portion 51 face each other in the Y-axis direction. In FIGS. 1 and 3, as an example of the arrangement relationship between the side faces 51c, 51d, 51e, and 51f and the exit surface 51a and the back surface 51b, the display side faces 51c, 51d, 51e, and 51f are substantially orthogonal to the exit surface 51a and the back surface 51b, respectively. State.

Next, the ridge portion 55 formed on the side of the exit surface 51a of the main body portion 51 will be described. Here, in order to simplify the description, the case where the plurality of ridge portions 55 have the same size will be described. The ridge portion 55 is transparent, and the light from the inside of the light guide plate 50 is emitted toward the transmissive image display unit 20. Further, as shown in FIG. 3, the outer shape of the ridge portion 55 has a shape of a lenticular lens.

The plurality of ridge portions 55 extend in the X-axis direction shown in FIGS. 1 and 3 and are arranged side by side in the Y-axis direction. The cross-sectional shape orthogonal to the extending direction of the ridge portion 55 is substantially uniform. As shown in FIG. 3 and FIG. 4, the plurality of ridge portions 55 can be disposed at a distance S from which the adjacent ridge portions 55 in the short-side direction (Y-axis direction) are fixed, and are adjacent to each other. A flat portion 55c is formed between the end of the ridge portion 55, that is, the bottom portion 55b. The coverage of the plurality of ridges 55 in the exit surface 51a of the main body portion 51 can be adjusted by changing the distance S (the length of the flat portion 55c). For example, when the ridge portions 55 adjacent to each other in the short-side direction are disposed without a gap, and the positions of the bottom portions 55b which are the ends of the adjacent ridge portions 55 are coincident with each other (the distance S shown in FIG. 4 is 0), Above coverage Become 100%. The coverage of the plurality of ridges 55 in the exit surface 51a of the main body portion 51 is usually 50% to 100%.

Next, various examples of the outer shape of the ridge portion 55 will be described. Here, the reference plane 51g is defined for convenience of explanation. That is, the reference surface 51g is defined as a surface parallel to the line connecting the bottom portions 55b to be joined to each other in the cross section of the ridge portion 55 as shown in FIG. 4 (indicated by a one-dot chain line in FIG. 4), in other words, a ridge is formed. The plane of the bottom surface of the portion 55. In the present embodiment, the back surface 51b (see FIG. 1) of the light guide plate 50 and the reference surface 51g are parallel to each other.

For example, the outer shape of the ridge portion 55 can be set by the combination of the aspect ratio [h _Ia /w _Ia ] shown below, the radius of curvature [r _I /w _Ia ] with respect to the width, and the bottom angle γ _I . The shape. Hereinafter, the aspect ratio [h _Ia /w _Ia ], the radius of curvature [r _I /w _Ia ] with respect to the width, and the bottom angle γ _{I will} be described with reference to Fig. 4 .

(I) Aspect ratio [h _Ia /w _Ia ]

In the aspect ratio [h _Ia /w _Ia ], when the width of the ridge portion 55 is w _Ia (μm) and the maximum height of the ridge portion 55 is h _Ia (μm), The ratio of the maximum height h _Ia to the width w _Ia .

(II) Radius of curvature with respect to width [r _I /w _Ia ]

The radius of curvature [r _I /w _Ia ] with respect to the width means that the width of the ridge portion 55 is w _Ia (μm), and the radius of curvature of the front end portion 55a of the ridge portion 55 is r _I (μm). The ratio of the radius of curvature r _I to the width w _Ia . The radius of curvature r _I of the front end portion 55a indicates a bend as the front end portion 55a of the top portion of the ridge portion 55. For example, the radius of curvature r _I of the distal end portion 55a is a radius of a circle in the case of a circle (a circle indicated by a broken line in Fig. 4) which is tangent to the distal end portion 55a as shown in Fig. 4 .

(III) Bottom angle γ _I

The bottom angle γ _I is an angle formed between the tangent plane P _{I of the} ridge portion 55 and the reference surface 51g at the position of the intersection of the contour line of the ridge portion 55 and the reference surface 51g in the cross section orthogonal to the extending direction . The bottom portion 55b is also a bottom edge portion of the ridge portion 55 with respect to the front end portion 55a. Thus, the bottom angle γ _I is also the bottom edge angle.

FIG. 4 shows a configuration of a cross section orthogonal to the extending direction of the ridge portion 55. w _Ia is the width of the ridge portion 55. Further, h _Ia is the thickness at the position of the front end portion 55a of the ridge portion 55. Thereby, the aspect ratio [h _Ia /w _Ia ] is the thickness (or height) of the ridge portion 55 at the position of the front end portion 55a with respect to the width of the ridge portion 55, that is, the thickness at the front end portion. ]/[Width of the ridges] corresponds. Generally, the thickness of the ridge portion 55 at the position of the front end portion 55a is the largest, and therefore the thickness of the ridge portion 55 at the position of the front end portion 55a is also the maximum thickness of the ridge portion 55. Further, the ratio described in the above (II) corresponds to the ratio of the radius of curvature r _I to the width of the ridge portion 55, that is, the [curvature radius] / [the width of the ridge portion].

In addition to the above-described (I) to (III) conditions, the outline of the ridge portion 55 may be defined as a conic curve represented by the following formula (1). In FIG. 5, the u _I v _I coordinate system is set as the u _I axis in the parallel direction (Y-axis direction) orthogonal to the extending direction (X-axis direction) of the ridge portion 55 shown in FIGS. 1 and 3. Here, the u _I axis corresponds to an axis (Y axis) parallel to the parallel direction of the plurality of ridge portions 55. The _I axis corresponds to an axis (Z axis) parallel to the thickness direction of the light guide plate 50. In the face of the u _I u _I v _I v _I of the coordinate system, the cross-sectional shape of the ridge line portion 55 of both end portions 55b, 55b positioned u _I axis, the front end portion 55a positioned v _I axis. At this time, the ridge portion 55 can be formed such that the angle formed by the tangential plane P _I and the reference surface 51g which are tangent to the ridge portion 55 is monotonously decreasing from the bottom portion 55b side to the front end portion 55a side of the ridge portion 55. .

In formula (1), w _Ia ridge portion of the length u 55 of the _I-axis direction. In the formula (1), h _Ia corresponds to the maximum height between the end portions 55b and 55b of the ridge portion 55 when the ridge portion 55 is formed into a shape indicated by v _I (u _I ). In the formula (1), k _Ia represents a parameter of the sharpness of the front end portion 55a of the ridge portion 55. For example, when the sharpness k _Ia is 0, the convex portion 55 is formed into a parabolic shape, and when the sharpness k _Ia is 1, the convex portion 55 is formed into a meander shape, and when the sharpness k _Ia is -1 The ridge portion 55 is formed to have a shape in which the ellipse is cut in half.

Further, the outer shape of the ridge portion 55 can be defined by a combination of the aspect ratio [h _Ia /w _Ia ] and the sharpness k _Ia when the outline of the ridge portion 55 is indicated by a specific conic curve. As an example of such a combination, the combination of the following (A), (B), etc. is mentioned.

(A)h _Ia /w _Ia =0.390, k _Ia =-0.390

(B)h _Ia /w _Ia =0.232, k _Ia =0.021

Fig. 5 shows the cross-sectional shape defined by the combination of the above (A) (h _Ia /w _Ia = 0.390, k _Ia = -0.390). Fig. 6 shows the cross-sectional shape defined by the combination of the above (B) (h _Ia /w _Ia = 0.232, k _Ia = 0.021). The coverage of the plurality of ridge portions 55 in the exit surface 51a of the main body portion 51 can be appropriately adjusted by adjusting the distance S between the adjacent ridge portions 55 in the short-side direction (Y-axis direction). The cross-sectional shape of the ridge portion 55 has a contour line that is symmetrical with respect to the v _I axis. The example of the width w _Ia is 10 μm or more and 2 mm or less, preferably 20 μm or more and 1 mm or less, and more preferably 50 μm or more and 600 μm or less.

Further, the outer shape of the ridge portion 55 can be defined by a combination of the aspect ratio [h _Ia /w _Ia ] and the sharpness k _Ia shown in the following (C).

(C)h _Ia /w _Ia =0.500, k _Ia =1.000

Fig. 7 shows the cross-sectional shape defined by the combination of the above (C) (h _Ia /w _Ia = 0.500, k _Ia = 1.000). In this case, the coverage of the plurality of ridge portions 55 in the exit surface 51a of the main body portion 51 can be adjusted to the distance S between the adjacent ridge portions 55 in the short-side direction (Y-axis direction). set up. The cross-sectional shape of the ridge portion 55 has a contour line that is symmetrical with respect to the v _I axis. The width w _{Ia is,} for example, 10 μm or more and 2 mm or less, preferably 20 μm or more and 1 mm or less, and more preferably 50 μm or more and 600 μm or less.

Next, the lens unit 52 will be described. In order to simplify the description, the description will be made assuming that the plurality of lens portions 52 have the same size. As shown in FIGS. 1 and 2, a plurality of lens portions 52 are formed on the back surface 51b of the main body portion 51. The lens portion 52 is transparent and is used to emit light propagating inside the light guide plate 50 from the exit surface 51a side. Further, each of the lens portions 52 has an outer shape and an arc shape.

As shown in FIG. 2, the plurality of lens portions 52 are arranged in a lattice shape in the short side direction (Y-axis direction) and the long-side direction (X-axis direction) of the main body portion 51, and are formed on the exit surface 51a from the light guide plate 50. The coverage distribution is optimized in such a manner that the uniformity of emitted light is 95%. As an example of satisfying the above-described uniformity of the amount of emitted light, the coverage of the square lattice of one lens portion 52 with respect to the central portion of the back surface 51b can be set to 78.54%. The lens portion 52 can also be configured as a thousand birds It is lattice-shaped and hexagonal. Further, the coverage ratio may be adjusted so that the lens portion 52 is not formed in a position corresponding to each of the lattices.

Next, the shape of each lens portion 52 will be described. 8 is a schematic view for explaining an example of the shape of the outer shape of the lens portion 52, and is a schematic view showing a cross-sectional configuration of the light guide plate 50 including the central axis C _II of the lens portion 52. In the lens portion 52, the top of the lens portion 52 is referred to as the front end portion 52a of the lens portion 52, and the bottom edge portion of the lens portion 52 is referred to as the bottom portion 52b of the lens portion 52. In the present embodiment, the shape of the lens portion 52 is a shape obtained by rotating the cross-sectional shape shown in FIG. 8 with the central axis C _II as a rotation axis. Thereby, the shape of the lens portion 52 is bilaterally symmetrical in any cross section including the central axis C _II . Further, the lens portion 52 has a shape in which the angle formed by the tangent plane P _II and the back surface 51b which are tangent to the lens portion 52 monotonously decreases from the bottom portion 52b side to the front end portion 52a side of the lens portion 52.

Various examples of the outer shape of the lens portion 52 will be described. For example, the outer shape of the lens portion 52 may be set to a combination of an aspect ratio [h _IIa /w _IIa ], a radius of curvature [r _II /w _IIa ] with respect to the width, and a bottom angle γ _II shown by the graph of FIG. 9 . And the shape of the regulation. Hereinafter, the aspect ratio [h _IIa /w _IIa ], the radius of curvature [r _II /w _IIa ] with respect to the width, and the bottom angle γ _{II will} be described with reference to Fig. 8 .

(I) Aspect ratio [h _IIa /w _IIa ]

The aspect ratio [h _IIa /w _IIa ] is the maximum height when the width of the lens portion 52 is w _IIa (μm) and the maximum height of the lens portion 52 is h _IIa (μm). The ratio of h _IIa to the width w _IIa .

(II) Curvature radius with respect to width [r _II /w _IIa ]

The radius of curvature [r _II /w _IIa ] with respect to the width means that the width of the lens portion 52 is w _IIa (μm), and the radius of curvature of the front end portion 52a of the lens portion 52 is r _II (μm). The ratio of the radius of curvature r _II to the width w _IIa . The radius of curvature r _II of the front end portion 52a indicates a bend as the front end portion 52a of the top portion of the lens portion 52. For example, the radius of curvature r _{II of the} distal end portion 52a is a radius of a circle in the case of a circle (a circle indicated by a broken line in Fig. 8) which is assumed to be tangent to the distal end portion 52a as shown in Fig. 8 .

(III) Bottom angle γ _II

The bottom angle γ _II is an angle formed between the tangent plane P _II and the back surface 51b of the lens portion 52 at the position of the intersection of the contour line of the lens portion 52 and the back surface 51b in the cross section of the central axis C _II . This bottom angle γ _II corresponds to the contact angle when the lens portion 52 is regarded as a liquid droplet. Further, the bottom portion 52b is also the bottom edge portion of the lens portion 52 with respect to the front end portion 52a. Thus, the bottom angle γ _II is also the bottom edge angle.

Hereinafter, the conditions in which the lens portion 52 satisfies the outer shape are specifically exemplified corresponding to the case of the aspect ratio [h _a /w _a ] shown in the graph of FIG. 9 .

(1)0.07 h _IIa /w _IIa <0.09 situation

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.8594 r _II /w _IIa 1.7969 and 12.46 γ _II 20.69

(2)0.09 h _IIa /w _IIa <0.11

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.5625 r _II /w _IIa 1.4375 and 14.48 γ _II 25.26

(3)0.11 h _IIa /w _IIa <0.13

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.4688 r _II /w _IIa 1.1979 and 17.22 γ _II 29.52

(4) 0.13 h _IIa /w _IIa <0.15

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.4018 r _II /w _IIa 1.4732 and 19.88 γ _II 58.14

(5)0.15 h _IIa /w _IIa <0.17

The outer shape of the lens portion 52 is a shape in which r/w _IIa and γ _II (°) satisfy the following conditions.

0.2734 r _II /w _IIa 1.2891 and 21.22 γ _II 61.44

(6)0.17 h _IIa /w _IIa <0.19

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.2431 r _II /w _IIa 1.1458 and 23.59 γ _II 64.16

(7)0.19 h _IIa /w _IIa <0.21

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.2188 r _II /w _IIa 1.2188 and 25.88 γ _II 86.33

(8)0.21 h _IIa /w _IIa <0.23

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.3125 r _II /w _IIa 1.1080 and 31.28 γ _II 86.68

(9)0.23 h _IIa /w _IIa <0.25

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.2865 r _II /w _IIa 1.0156 and 33.53 γ _II 86.96

(10)0.25 h _IIa /w _IIa <0.27

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.4567 r _II /w _IIa 0.9375 and 44.76 γ _II 87.20

(11)0.27 h _IIa /w _IIa <0.29

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.6920 r _II /w _IIa 0.7813 and 68.14 γ _II 77.44

(12)0.29 h _IIa /w _IIa <0.31

The outer shape of the lens portion 52 is a shape in which r _II /w _IIa and γ _II (°) satisfy the following conditions.

0.6458 r _II /w _IIa 0.7292 and 69.47 γ _II 78.25

Since FIG. 8 shows a configuration including a cross section of the central axis C _II of the lens portion 52, the width w _IIa corresponds to the maximum width of the lens portion 52. Further, h _IIa is the thickness at the position of the front end portion 52a of the lens portion 52. Thus, the aspect ratio [h _IIa /w _IIa ] is the thickness (or height) of the lens portion 52 at the position of the end portion 52a before the maximum width of the lens portion 52, that is, the thickness at the position of the front end portion. / [Maximum width of the lens portion] corresponds. Generally, the thickness of the lens portion 52 at the position of the front end portion 52a is the largest, and therefore the thickness of the lens portion 52 at the position of the front end portion 52a is also the maximum thickness of the lens portion 52. Further, the ratio described in the above (II) corresponds to the ratio of the radius of curvature r _II to the maximum width of the lens portion 52, that is, the "curvature radius" / [the maximum width of the lens portion].

Further, as shown in FIG. 10, the outer shape of the lens portion 52 may be defined as a conic curve in the cross-sectional configuration of the lens portion 52 including the central axis C _II of the lens portion 52. Specifically, as shown in FIG. 10, the u _II v _II coordinate system can be set, and the cross-sectional shape of the lens portion 52 can be defined by the conic curve v _II (u _II ) shown by the following formula (2). The v _II axis of the u _II v _II coordinate system corresponds to the central axis C _II of the lens portion 52 in FIG. Further, the u _II axis corresponds to the X-axis direction shown in FIGS. 1 and 2.

In the formula (2), k _IIa represents a parameter of the sharpness of the conic curve shown by the formula (2), and indicates the sharpness of the front end portion 52a of the lens portion 52. For example, when the sharpness k _IIa is 0, the lens portion 52 is formed in a parabolic shape, and when the sharpness k _IIa is 1, the lens portion 52 is formed in a meandering shape, and when the sharpness k _IIa is -1, the lens is formed. The portion 52 is formed to have a shape in which the ellipse is cut in half.

Further, the outer shape of the lens portion 52 can be defined by a combination of the aspect ratio [h _IIa /w _IIa ] and the sharpness k _IIa when the outline of the lens portion 52 is expressed as a specific conic curve. As an example of such a combination, the following combinations of (a) to (c) and the like can be mentioned.

(a) h _IIa /w _IIa =0.220, k _IIa =0.200

(b) h _IIa /w _IIa =0.120, k _IIa =0.400

(c) h _IIa /w _IIa =0.220, kI _Ia =0.000

The width w _{IIa is,} for example, 5 μm or more and 1 mm or less, preferably 10 μm or more and 500 μm or less. The lens portion 52 having the size as described above is a so-called microlens.

The material of the lens portion 52 and the ridge portion 55 can be made of the same material as that of the body portion 51. Further, the material of the lens portion 52 and the ridge portion 55 may be different from the material of the main body portion 51 as long as it is a light transmissive material.

The main body portion 51 of the light guide plate 50 having the above-described configuration may be a single-layer plate-like body including a single light-transmitting material, or a plate-like body having a multilayer structure in which layers of mutually different light-transmitting materials are laminated. . Further, when the material of the lens portion 52 and the ridge portion 55 is the same as that of the main body portion 51, the light guide plate 50 may be a plate-like body including a single light-transmitting material.

Further, when a light-transmitting resin material is used as the light-transmitting material constituting the main body portion 51, the lens portion 52, and the ridge portion 55, an ultraviolet absorber or an antistatic agent may be added to the light-transmitting resin material. Additives such as antioxidants, processing stabilizers, flame retardants, lubricants, etc. These additives may be used alone or in combination of two or more. In addition, when the ultraviolet ray absorbing agent is added to the light guide plate 50, when the light emitted from the light source unit 60 contains a large amount of ultraviolet light, it is possible to prevent deterioration of the light guide plate 50 due to ultraviolet rays. good.

Examples of the ultraviolet absorber include a benzotriazole-based ultraviolet absorber, a benzophenone-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, a malonate-based ultraviolet absorber, and an oxalic acid-aniline-based ultraviolet absorber. three It is a UV absorber or the like, preferably a benzotriazole-based ultraviolet absorber, and three It is a UV absorber.

Usually, the light-transmitting resin material is not used as an additive, but a light diffusing agent may be added as long as it does not deviate from the gist of the present invention.

The light diffusing agent is a powder having a refractive index different from that of the above-described light-transmitting material (or transparent material) mainly constituting the light guide plate 50, specifically, the main body portion 51, the lens portion 52, and the ridge portion 55. It is used by being dispersed in a light-transmitting material. The light diffusing agent contains, for example, organic particles such as styrene resin particles or methacrylic resin particles, inorganic particles such as potassium carbonate particles and cerium oxide particles. The particle size of the light diffusing agent is usually from 0.8 μm to 50 μm.

The light guide plate 50 including the lens portion 52 and the ridge portion 55 can be manufactured by inkjet printing (inkjet method), photopolymer method, extrusion molding, or extrusion molding.

When the light guide plate 50 is produced by inkjet printing (inkjet method) or photopolymer method, as the material of the lens portion 52 and the ridge portion 55, an ultraviolet curable resin can be used, and as the ultraviolet curable resin, acrylic ultraviolet curing can be used. Resin.

An example in which the material of the lens portion 52 is an acrylic ultraviolet curable resin and the method of manufacturing the light guide plate 50 in the case of the ink jet method will be described. In this case, first, the main body portion 51 which is a plate-like body having the ridge portion 55 on the side of the exit surface 51a is formed by extrusion molding or extrusion molding. Then, the ultraviolet curable resin is dropped (printed) while the ink jet head is operated in accordance with the surface of the back surface 51b of the main body portion 51 thus formed. Then, by curing the ultraviolet curable resin by ultraviolet rays, it is formed. Lens portion 52.

In the case where the inkjet method is employed in the formation of the lens portion 52, a printing plate or the like which is necessary for screen printing as an example of another printing method is not required. Usually, the plurality of lens portions 52 are appropriately repeated in the design step and the trial step, and are arranged in a specific dot pattern so that the brightness of the light emitted from the exit surface 51a becomes high. In the ink jet method which does not have a printing plate, the time required for the determination of the above specific dot pattern can be shortened. As a result, the light guide plate 50 can be manufactured more efficiently.

Next, the shape of the lens formed when the lens portion 52 is printed by the above-described inkjet method will be described. Here, when the number of inks to be dropped to form one lens portion 52 (the number of drops) and the liquid-repellent treatment to be performed on the surface of the back surface of the main body portion 51 are respectively changed, the case is formed under the following conditions. The shape of the lens portion 52 is observed.

Condition 1: Printing is performed on the surface on which the liquid dispensing is applied, and the number of drops is fixed.

Condition 2: Printing is performed while changing the number of drops by applying the surface to which the liquid is applied

Condition 3: Printing on the surface where the fluorine plasma treatment is carried out while changing the number of drops

The lens portion 52 printed according to the above conditions 1 to 3 was observed, and the aspect ratio [h _IIa /w _IIa ] and the sharpness k _IIa were calculated. The calculation results obtained by this observation are shown in Figs. 11(a) to (c). Fig. 12 is a graph in which the calculation results obtained by observation of each of Figs. 11(a) to (c) are summarized in one table. According to the distribution of the aspect ratio [h _IIa /w _IIa ] and the sharpness k _IIa shown in Fig. 12, the shape of the lens portion 52 printed by the ink jet method has an aspect ratio as shown in the frame shown in Fig. 12 [ The shape within the range of h _IIa /w _IIa ] and the sharpness k _IIa .

Further, the relationship between the lens shape defined by the sharpness k _a and the aspect ratio [h _IIa /w _IIa ] and the radius of curvature [r _II /w _IIa ] with respect to the width can be obtained from the calculation result obtained by the above observation. The relationship between the lens shape defined by the sharpness k _a and the aspect ratio [h _IIa /w _IIa ] and the bottom angle γ _II with respect to the width is shown in Figs. 13 and 14 , 15 and 16 , respectively. 13 and 15 show a range in which the sharpness k _IIa is 0.1 or more and 0.9 or less. 14 and 16 show that the sharpness k _IIa is in the range of -0.9 or more and 0 or less. In Figs. 13 to 16, the unit marked with hatching corresponds to the lens shape defined by the aspect ratio [h _IIa /w _IIa ] and the sharpness k _IIa in the frame in Fig. 12 .

12 to 16, the shape of the lens portion 52 which can be printed by the ink jet method can be exemplified. Specifically, the shape of the lens portion 52 exemplified in the above embodiment, that is, the shape defined by any combination in the graph shown in FIG. 9 can be used. In other words, since the shape of the lens portion 52 defined by any one of the combinations in the graph shown in FIG. 9 can be printed by the inkjet method, it can be said that when the lens portion 52 is formed on the main body portion 51 of the light guide plate 50, A shape that can be easily formed.

Further, the outer shape of the lens portion 52 is defined by a combination of the aspect ratio [h _IIa /w _IIa ] shown in the graph of Fig. 9 and the radius of curvature [r _II /w _IIa ] with respect to the width and the bottom angle γ _II . In the range of the shape, when the contour line of the lens portion 52 is a conic curve represented by the above formula (2), the condition of the parameter k _IIa indicating the sharpness may be further added. Hereinafter, the conditions of the outer shape of the lens portion 52 are specifically exemplified for the aspect ratio [h _IIa /w _IIa ] shown in the graph of each of FIG.

(1)0.07 h _IIa /w _IIa <0.09 situation

The outer shape of the lens portion 52 is -0.15 k _IIa 0.45 shape.

(2)0.09 h _IIa /w _IIa <0.11

The outer shape of the lens portion 52 is -0.15 k _IIa The shape of 0.55.

(3)0.11 h _IIa /w _IIa <0.13

The outer shape of the lens portion 52 is -0.15 k _IIa The shape of 0.55.

(4) 0.13 h _IIa /w _IIa <0.15

The outer shape of the lens portion 52 is -0.65 k _IIa The shape of 0.55.

(5)0.15 h _IIa /w _IIa <0.17

The outer shape of the lens portion 52 is -0.65 k _IIa The shape of 0.65.

(6)0.17 h _IIa /w _IIa <0.19

The outer shape of the lens portion 52 is -0.65 k _IIa The shape of 0.65.

(7)0.19 h _IIa /w _IIa <0.21

The outer shape of the lens portion 52 is -0.95 k _IIa The shape of 0.65.

(8)0.21 h _IIa /w _IIa <0.23

The outer shape of the lens portion 52 is -0.95 k _IIa 0.45 shape.

(9)0.23 h _IIa /w _IIa <0.25

The outer shape of the lens portion 52 is -0.95 k _IIa 0.45 shape.

(10)0.25 h _IIa /w _IIa <0.27

The outer shape of the lens portion 52 is -0.95 k _IIa The shape of 0.05.

(11)0.27 h _IIa /w _IIa <0.29

The outer shape of the lens portion 52 is -0.75 k _IIa -0.55 shape.

(12)0.29 h _IIa /w _IIa <0.31

The outer shape of the lens portion 52 is -0.75 k _IIa -0.55 shape.

Here, the lens shape is described as a lens portion 52 that can be printed by an inkjet method. However, as described above, the lens shape may be formed by extrusion molding or extrusion molding other than the inkjet method. The lens portion 52. In this case, it is also possible to have a shape other than the range shown in the graphs of FIGS. 9 and 17.

Further, the light guide plate 50 in which the lens portion 52 and the ridge portion 55 are formed may be manufactured by extrusion molding or extrusion molding. In this case, the material of the lens portion 52 and the ridge portion 55 is the same as that of the body portion 51. Further, the light guide plate 50 having the main body portion 51, the ridge portion 55, and the lens portion 52 as the plate-like body including the ridge portion 55 can also be cut by a plate material containing, for example, a light transmissive material (or a transparent material). Manufactured by the method.

Next, the operation and effect of the light guide plate 50 will be described as an example of application to the transmissive image display device 10 as a part of the surface light source device 30 as shown in FIG.

When the point light source 61 included in the light source unit 60 emits light, the light from the point light source 61 enters the light guide plate 50 from the side surface 50a of the light guide plate 50 opposed to the point light source 61. The light incident on the light guide plate 50 is transmitted through the light guide plate 50 while being totally reflected. When the light propagating in the light guide plate 50 is incident on the lens portion 52, the light in the lens portion 52 is reflected under conditions other than the total reflection condition. Therefore, the light reflected in the lens portion 52 is emitted from the exit surface 51a. Since the ridge portion 55 is formed on the exit surface 51a, the light emission efficiency can be improved as compared with the light guide plate that does not form the ridge portion on the exit surface. The brightness is increased by these effects. Further, in the transmissive image display device 10 of the present embodiment, since the transmissive image display unit 20 is provided on the light guide plate 50, the transmissive image display unit 20 is provided. The overtype image display unit 20 is illuminated by light having a higher brightness. As a result, the brightness of the image displayed by the transmissive image display unit 20 can be improved.

Then, the light emission efficiency of the light guide plate 50 in which the lens portion 52 and the ridge portion 55 are formed is higher than that of the conventional light guide plate according to the simulation result. However, the invention is not limited to such simulations.

Fig. 18 is a schematic view showing a simulation model. For the sake of convenience of explanation, the constituent elements corresponding to the constituent elements shown in FIG. 1 are described by labeling M as the light guide plate 50 _M. As shown in Fig. 18, the simulation system is arranged at positions opposite to the side faces 50 _M a (51 _M c) and 50 _M b (51 _M d) of the light guide plate 50 _{M which} is the evaluation target described in detail later. In the model in which the light source 61 _M and 61 _{M are} disposed as the reflection sheet of the reflection portion 70 _M under the light guide plate 50 _M, the light emission efficiency E is calculated using the ray tracing method.

The simulation conditions are as follows.

. The constituent material of the light guide plate 50 _M: 55 _M comprises a ridge portion of the main body portion and the lens portion 51 _M 52 _M assume PMMA (refractive index: 1.49)

. The shape of the light guide plate 50 _M (the shape observed from the thickness direction): rectangular

. The length of the long side of the light guide plate 50 _M is W1: 540 mm

. The length of the short side of the light guide plate 50 _M is W2: 20 mm

. Thickness t of the body portion 51 _M : 3 mm

. The distance between the front end portion 52 _M a of the lens portion 52 _M of the light guide plate 50 _M and the reflection portion 70 _M : 0.1 mm

. Reflecting portion 70 _M : Assume the same reflection characteristics as the white reflecting plate taken out from the backlight module used in the "KDL40EX7" manufactured by Sony Corporation

. Wavelength of light emitted from point source 61 _M : assumed 550 nm

. Distance between point light source 61 _M and light guide plate 50 _M : 0.05 mm

Further, a periodic boundary condition is assumed in the side surface 51 _M e and the side surface 51 _M f of the body portion 51 _M . That is, it is assumed that in the side faces 51 _M e and 51 _M f , the light is totally reflected and returned to the light guide plate 50 _M. In this manner, by providing a periodic boundary condition in the short-side direction (Y-axis direction) of the light guide plate 50 _M , a simulation of the light guide plate in which the length in the short-side direction is substantially infinite is performed.

Under the above-described conditions, the ratio of the amount E _o of all the outgoing light from the exit surface 51 _M a to the amount E _i of the light incident on the light guide plate 50 _M to be evaluated is calculated, thereby obtaining the light exit efficiency. E(=E _o /E _i ).

Next, the light guide plate 50 _M to be evaluated will be described. As the light guide plate 50 _{M to} be evaluated, 12 types of light guide plates 50 _M of Examples 1 to 12 in which the shape of the emission surface 51 _M a side and the shape of the back surface 51 _M b side are combined as shown in Table 1 below are assumed.

<Outlet surface 51 _M a side>

The light guide plate 50 _M of the example 1 to the example 6 is assumed to have a lenticular lens 55 _M as a ridge portion formed on the side of the exit surface 51 _M a . Specifically, as shown in FIG. 18, it is assumed that the lenticular lenses 55 _M adjacent in the short-side direction are arranged at a predetermined interval. Here, the width w _{Ia of the} lenticular lens 55 _M is set to 475 μm, the interval S between the lenticular lenses 55 _M is set to 25 μm, and the plurality of lenticular lenses 55 _M of the exit faces 51 _M a of the main body portion 51 _{M are set} . The coverage is set to 95%.

The light guide plate 50 _M of the example 7 to the example 9 is formed with a ridge 55 _M as a ridge portion on the side of the exit surface 51 _M a . Specifically, it is contemplated in place of the lenticular lens 55 _M of FIG. 7 and FIG Prism 18 to FIG. 55 _M, and adjacent to the short-side direction of Prism 55 _M are arranged without a gap by another. Here, the width w _{Ia of}稜鏡55 _M is set to 500 μm, the interval S between 稜鏡55 _M is set to 0 μm, and a plurality of 稜鏡55 _M of the exit surface 51 _M a of the main body portion 51 _{M are set} . The coverage is set to 100%.

When the cross-sectional shape of the lenticular lens 55 _M and the 稜鏡 55 _M is defined as a conic curve represented by the following formula (3), it is assumed that the aspect ratios h _Ia /w _Ia and the sharpness k _Ia are as shown in Table 1, respectively.

On the other hand, it is assumed that the lenticular lens 55 _M or 稜鏡 55 _{M as the} ridge portion is not formed on the exit surface 51 _M a side of the light guide plate 50 _M of Examples 10 to 12, and the exit surface 51 _M a becomes substantially flat. .

<Back 51 _M b side>

On the back surface 51 _M b side of the light guide plate 50 _M of Examples 1 to 12, microlenses 52 _M as lens portions were arranged at regular intervals. Specifically, a square lattice in which a plurality of squares are arranged is set on the back surface 51 _M b , and one lens portion 52 _M is disposed in each square which is a constituent unit of the square lattice. Further, the microlens 52 _M is a plurality of lenticular lenses 55 _M arranged on the emission surface 51 _M a side at a coverage of 100%, and is optimized to have a coverage distribution arrangement in such a manner that the uniformity of the emitted light amount is 95% or more. Figure 19 is an example of the coverage distribution of the microlens 52 _M in Examples 1 to 6, showing the distance (mm) from the center portion of the light guide plate 50 _M on the horizontal axis and the coverage ratio (%) on the vertical axis. . Figure 20 is an example of the coverage distribution of the microlens 52 _M in Examples 7 to 12, showing the distance (mm) from the center portion of the light guide plate 50 _M on the horizontal axis and the coverage ratio (%) on the vertical axis. . According to Fig. 19 and Fig. 20, in any of the examples, the coverage of the square lattice of the central portion of the one microlens 52 _M with respect to the central portion in the X-axis direction of the back surface 51 _M b is 74.61%.

When the cross-sectional shape of the microlens 52 _M is defined as a conic curve shown by the following formula (4), the aspect ratios h _IIa /w _IIa and the sharpness k _IIa are respectively shown in Table 1.

Next, the point light source 61 _{M will} be described in detail. The point light sources 61 _M and 61 _M are arranged in the short-side direction of the light guide plate 50 _M , respectively, and the distance L1 from each end portion is 5 mm, and the distance L2 between the light sources is 10 mm. The point light source 61 _M is a surface light source having a length of 5.5 mm in the lateral direction (depth direction) and a length of 2 mm in the longitudinal direction (the thickness direction of the light guide plate).

Fig. 21 is a view showing an example of the directivity characteristic (light distribution characteristic) of the point light source 61 _M. The horizontal axis of Fig. 21 indicates the exit angle θ (°), and the vertical axis indicates the normalized outgoing light intensity normalized by the maximum outgoing light intensity. In the present embodiment, θ = 0 corresponds to the X-axis direction in Fig. 1 . The point light source 61 _M assumes a so-called Lambertian type light source, and the point light source 61 _M includes, for example, a light emitting diode. The Lambertian-type light source has the following characteristics: the maximum exiting light intensity at which the intensity of the emitted light is maximum is about 0° (front direction), and is substantially monotonous as the inclination (emission angle) from the front direction becomes large. Decrement. The PD in Fig. 21 indicates the directivity characteristic in the case of theoretically complete diffusion, and it is assumed in the present simulation that the light source of the characteristic is obtained.

The results of the above simulations of the respective light guide plates 50 _M of Examples 1 to 12 are shown in the graph of Fig. 22 . In the graph of Fig. 22, the numerical value indicating the column of each simulation result indicates the light emission efficiency E (%).

It can be confirmed that the light emission efficiency E of each of the light guide plates 50 _M of Examples 1 to 9 in which the lenticular lens 55 _M or the 稜鏡 55 _{M as} the ridge portion is formed on the exit surface 51 _M a side is higher than The light exiting efficiency E of each of the light guide plates 50 _M of the examples 10 to 12 of the lenticular lens 55 _M or the 稜鏡 55 _{M as} the lenticular portion 55 _M a side is not present on the exit surface 51 _M a side. Thereby, the light emission efficiency E can be improved by forming the ridge portions such as the lenticular lens 55 _M or the 稜鏡 55 _M on the side of the exit surface 51 _M a . In other words, it has been confirmed that the brightness can be improved by using the light guide plate 50 _{M having a} high emission efficiency for the surface light source device.

The embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments and the above-described simulations, and various modifications can be made without departing from the spirit and scope of the invention.

In the above embodiment, it has been described that the plurality of lens portions 52 formed on the back surface 51b can be set to have an aspect ratio [h _IIa /w _IIa ] as shown in Fig. 9 and a radius of curvature with respect to the width [r _II /w _IIa] And the range of shapes defined by the combination of the bottom angle γ _II . However, at least half of the plurality of lens portions formed on the back surface 51b may be the lens portion 52 described in the above embodiment. In other words, the plurality of lens portions formed on the back surface 51b may include a half of which is the first lens portion as the lens portion 52 and the remaining half is a second lens portion that does not satisfy the conditions described in the above embodiments. The ratio of the number of the first lens portions of the lens portion 52 to the number of the second lens portions may be 6:4.

Further, the shape of the lens portion 52 is preferably such that the angle formed by the tangent plane of the lens portion 52 and the back surface 51b is monotonously decreasing from the bottom side to the front end side of the lens portion 52 as illustrated in FIG. However, the lens portion 52 has a shape defined by a combination of h _IIa /w _IIa , r _II /w _IIa and γ _II shown in the graph of Fig. 9, and the tangent plane of the lens portion 52 and the back surface 51b are formed. The angle to the front end portion 52a side may not be monotonously decreasing.

Further, the arrangement position of the light source unit 60 is not limited to two locations. For example, the light source unit 60 may be disposed at one location. In this case, the light source unit 60 is disposed in one of the side surface 51c and the side surface 51d shown in Fig. 1 . A reflective tape such as a lens tape or a white diffusion tape for preventing light leakage may be attached to the other side opposite to one side of the light incident from the light source unit 60.

Further, in the above simulation, the point light source 61 having the directivity characteristic in the case of theoretically completely diffused is shown, but the surface light source device 30 and the transmissive image display device 10 of the present embodiment are not limited to this. For example, as shown in FIG. 21, it may be a point light source having a Lambertian-type directional characteristic, and the scalloped characteristic of the Lambertian type satisfies with respect to a pointing indicating complete diffusion. The PD is offset by -0.6% when the exit angle is 30° and the curve PD1 (shown by the dotted line in Fig. 21) when the exit angle is 60°, and when the exit angle is 30°. The exit angle and the normalized radiation intensity of the region between the curve PD2 (shown by the broken line in Fig. 21) shifted by 6.6% and offset by 16.4% when the exit angle is 60°.

Further, in the above-described embodiment, as an example of the shape of the outer shape of the ridge portion 55, the radius of curvature [r _I ] with respect to the (II) width and the width (r) can be exemplified by (I) aspect ratio [h _Ia /w _Ia ] /w _Ia ] and (III) Examples of a specific shape of the bottom angle γ _I . Further, in addition to the above conditions, the outline of the ridge portion 55 can be defined as a conic curve shown by the following formula (5). However, the invention is not limited thereto.

For example, when the u _I v _I coordinate system is set to the cross section orthogonal to the extending direction of the convex portion 55 (the u _I axis direction is set to the X axis direction and the v _I axis direction is set to the Z axis direction), The cross-sectional shape of the ridge portion 55 is represented by v _I (u _I ) satisfying the following formula (6).

[Equation 6] 0.95 × v _I0 (u _I ) ≦ v _I (u _I ) ≦ 1.05 × v _I0 (u _I ) (6) wherein, in the formula (6), v _I0 (u _I ) satisfies

[Number 7]

Formula (7) and the Department of the formula (1) in the same manner, w _{Ia I} is the length of the U-axis direction 55 of ridge portions, h _Ia and the ridge line portion 55 is set to v _I0 (u _I) of the shape shown in FIG. In the case of the case, the maximum height between the end portions 55b and 55b of the ridge portion 55 corresponds to each other. k _Ia is a parameter indicating the sharpness of the front end portion 55a of the ridge portion 55. For example, when the sharpness k _Ia is 0, the convex portion 55 is formed into a parabolic shape, and when the sharpness k _Ia is 1, the convex portion 55 is formed into a meander shape, and when the sharpness k _Ia is -1 The ridge portion 55 is formed to have a shape in which the ellipse is cut in half.

Further, in the invention of the present invention, the outer shape of the ridge portion 55 provided on the exit surface side may be formed into an outer shape of the ridge portion 155 shown below. In other words, in the cross section orthogonal to the extending direction of each of the plurality of ridge portions 155, the apex (front end portion) 155a in the cross section of the ridge portion 155 is raised up to the point P on the contour line. The length of the contour line is set to L, and the axis passing through both end portions of the ridge portion 155 is set as the u-axis, and the inclination (absolute value) of the u-axis of the cross-sectional shape of the point portion P with respect to the ridge portion 155 is set. When it is α, it may be formed into a shape in which the following formulae (8) and (9) are satisfied in the range of -0.20 < L < 0.20, and 0 < α... (8)

At -0.65<L -0.20 range and 0.20 In the range of L<0.65, the following formulas (10) and (11) are satisfied,

At -1.00<L -0.65 range and 0.65 In the range of L < 1.00, the following formulas (12) and (13) are satisfied.

0<α.........(12)

In the light guide plate in which a plurality of ridge portions 155 having a cross-sectional shape in which α and Δα/ΔL satisfy the above-described conditions are formed on the light-emitting surface, light incident on the light incident surface of the light guide plate easily follows the ridge portion 155. The direction of extension extends. Therefore, when light propagates from the incident position of the light in the light guide plate, the diffusion of light is suppressed, so that crosstalk can be reduced. In addition, the L system sets the center in the u-axis direction to 0, and increases toward the right from the center (L>0), and decreases toward the left from the center (L<0).

The outer shape of the ridge portion 155 is preferably in the range of -0.20 < L < 0.20, and satisfies the following formula (14).

The outer shape of the ridge portion 155 is preferably -0.65 < L -0.20 range and 0.20 In the range of L < 0.65, the following formula (15) is satisfied.

The outer shape of the ridge portion 155 is preferably -1.00 < L -0.65 range and 0.65 In the range of L < 1.00, the following formula (16) is satisfied.

The outer shape of the ridge portion 155 is preferably such that when the width of the ridge portion 155 is w _a and the maximum height of the ridge portion 155 is h _a , the aspect ratio of the ridge portion 155 (h _a /w _a ) is 0.3 or more and less than 0.5.

Embodiments A1 to A5 which are examples of the outer shape of the ridge portion 155 as described above will be described with reference to Figs. 23 to 27 . 23 to 27 are views showing an example of a cross-sectional shape orthogonal to the extending direction of the ridge portion. Fig. 23 shows an embodiment A1, Fig. 24 shows an embodiment A2, Fig. 25 shows an embodiment A3, Fig. 26 shows an embodiment A4, and Fig. 27 shows an embodiment A5. In FIGS. 23 to 27, the uv coordinate system is set as the u-axis in the direction orthogonal to the extending direction of the ridge portion 155. In the uv coordinate system, the cross-sectional shape of the ridge portion 155 has both end portions 155b and 155b on the u-axis. In the uv coordinate system, the v-axis passes through the center between the end portions 155b, 155b on the u-axis. In the embodiment shown in FIGS. 1 and 2, the u-axis direction is the Y-axis direction. Further, the v-axis direction is the Z-axis direction.

In the uv coordinate system, the cross-sectional shape of the ridge portion 155 satisfies the following formulas (17) to (22). Here, the position of the ridge portion 155 in the u-axis direction is w, and the inclination of the u-axis with respect to the cross-sectional shape of the ridge portion 155 at the position w is α. In the cross section orthogonal to the extending direction of the ridge portion 155, the length from the apex 155a in the cross section of the ridge portion 155 to the point P on the contour line along the contour line is set to L. The position of the point P in the u-axis direction is the above-described position w, and the inclination α (absolute value) is the inclination of the point P. Δα/ΔL is the ratio of the amount of change in α to the amount of change in L. The angle α of the cross-sectional shape of the ridge portion 155 on the inclination α-position w (point P) is smaller than the angle at which the u-axis intersects (0 α 90).

In the u-axis direction, the length from the center O(0, 0) of the ridge portion 155 to the end portion 155b is set to 1. The position of the end portion 155b of the ridge portion 155 becomes w = -1, 1. The position w increases more toward the right from the center O (w>0), and decreases more toward the left from the center O (w<0). Further, in the v-axis direction, the height corresponding to the length of the end portion 155b from the center O of the ridge portion 155 is referred to as h _a . The position w is _a value normalized by the width w _{a of the} ridge portion 155, and the value of the position is expressed by _a ratio with respect to the width w _a .

The cross-sectional shape of the ridge portion 155 is in the first section A (the range of -0.20 < L < 0.20), and satisfies the following formulas (17) and (18).

0<α.........(17)

In the first section A, the cross-sectional shape of the ridge portion 155 is increased by the inclination α. In other words, the further away from the center O, the greater the inclination α.

The cross-sectional shape of the ridge portion 155 is in the second interval B (-0.65 < L -0.20 range and 0.20 The range of L < 0.65 satisfies the following formulas (19) and (20).

In the second section B, the cross-sectional shape of the ridge portion 155 is increased or not changed. In other words, the further away from the center O, the greater the inclination α or fixed.

The cross-sectional shape of the ridge portion 155 is in the third interval C (-1.00 < L -0.65 range and 0.65 The range of L < 1.00 satisfies the following formulas (21) and (22).

0<α.........(21)

In the third section C, the cross-sectional shape of the ridge portion 155 is increased by the inclination α. In other words, the further away from the center O, the greater the inclination α.

In the first interval A, Δα/ΔL may satisfy the following formula (23).

In the second interval B, Δα/ΔL may satisfy the following formula (24).

In the third interval C, Δα/ΔL may satisfy the following formula (25).

Fig. 28 is a view showing a part of a cross-sectional shape of the ridge portion 155. When any two points on the outer shape of the ridge portion 155 are P ₁ and P ₂ , ΔL = L _{2 -} L ₁ (where L ₂ > L ₁ ), Δα = α _{2 -} α ₁ (where α ₂ α ₁ ). Where L ₁ is the position of the point P ₁ on the contour line, and α ₁ is the inclination of the point P ₁ (the angle of intersection with the u-axis). Similarly, the position of the point P ₂ on the L ₂ line contour line, and the inclination of the α ₂ line point P ₂ (the angle of intersection with the u axis).

29 to 31 are views showing the relationship between the position L on the contour line of the cross-sectional shape of the ridge portion 155 and the inclination angle α. In FIGS. 29 to 31, the position L is indicated on the horizontal axis and the inclination angle α [degrees] is indicated on the vertical axis. On the horizontal axis, L = 0 indicates the center of the outline of the ridge portion 155. When the cross-sectional shape of the ridge portion 155 is L=0, the apex (front end portion 155a) of the ridge portion 155 is formed, and the inclination angle α=0. In the position L, the position of the end portion 155b in the width direction (u-axis direction) of the ridge portion 155 is L=1, which is represented by a ratio. L = 0.5 indicates the position between the center O and the end portion 155b. In Figures 29 to 31, L is 0. L The tilt angle α, L is -1 in the range of 1 L The value of the tilt angle α in the range of 0 becomes 0. L The return value of the value of 1.

Fig. 29 (a) shows an embodiment A1, Fig. 29 (b) shows an embodiment A2, Fig. 30 (a) shows an embodiment A3, Fig. 30 (b) shows an embodiment A4, and Fig. 31 shows an embodiment A5. The cross-sectional shape of the ridge portion 155 of the embodiment A1 to A5 In the first interval A, the inclination angle α is increased. That is, the inclination angle α is larger as it goes away from the center O toward the end portion 155b (L=1) side.

The cross-sectional shape of the ridge portion 155 of the embodiment A1 is in the second section B, and the inclination angle α is increased or not changed. Specifically, the cross-sectional shape of the ridge portion 155 of the embodiment A1 is at 0.20. In the range of L < 0.60, the inclination angle α is fixed without being changed. The cross-sectional shape of the ridge portion 155 of the embodiment A1 is at 0.60. In the range of L < 0.65, the inclination angle α is increased.

The cross-sectional shape of the ridge portion 155 of the embodiment A2 to A5 is in the second section B, and the inclination angle α is increased. That is, the inclination angle α is larger as it goes away from the center O toward the end portion 155b (L=1) side.

The cross-sectional shape of the ridge portions 155 of the embodiments A1 to A5 is in the third section C, and the inclination angle α is increased. That is, the inclination angle α is larger as it goes away from the center O toward the end portion 155b (L=1) side.

Fig. 32 is a view showing the relationship between the length L of the line segment of the cross-sectional shape of the ridge portion 155 and Δα/ΔL. In Fig. 32, the line segment length L is indicated on the horizontal axis and Δα / ΔL is indicated on the vertical axis. In Figure 32, it indicates that L is 0. L △α/△L, L is -1 in the range of 1 L The value of Δα/ΔL becomes 0 in the range of 0 L The return value of the value of 1. Here, the line length L is represented by a ratio when the length along the contour line from the vertex (front end portion) 155a to the end portion 155b is "1".

The cross-sectional shape of the ridge portions 155 of the embodiments A1 to A5 is in the first section A, and Δα/ΔL is 150 or more and less than 260. The cross-sectional shape of the ridge portion 155 of the embodiments A1 to A5 is in the second section B, and Δα/ΔL is 0 or more and less than 30. The cross-sectional shape of the ridge portion 155 of the embodiments A1 to A5 is in the third section C, Δα/ΔL is 5 or more and less than 75.

(aspect ratio)

The width w _{a of the} ridge portion 155 in the u-axis direction is usually smaller than the distance between the adjacent point light sources 61. The width w _{a is,} for example, 50 μm to 2000 μm, preferably 100 μm to 1000 μm, and more preferably 200 μm to 800 μm. h _a corresponds to the maximum height between the end portions 155b, 155b of the ridge portion 155. The aspect ratio (h _a /w _a ) of the ridge portion 155 is a ratio of the maximum height h _a to the width w _a of the ridge portion 155 . The aspect ratio of the ridge portion 155 is 0.3 or more and less than 0.5.

The cross-sectional shape of the plurality of ridge portions 155 is substantially the same between the ridge portions 155. However, the cross-sectional shape of each of the plurality of ridge portions 155 may be different as long as it satisfies the cross-sectional shape of the above formulas (17) to (22).

For example, the light guide plate including the above-described ridge portion 155 is not limited to a single layer structure, and may have a multilayer structure. In the present embodiment, the thickness of the light guide plate including the ridge portions 155 is defined as the thickness of the body portion. The distance between the top (front end portion) 155a of the plate thickness rib portion 155 of the main body portion and the back surface of the body portion is usually 0.5 mm to 8 mm, preferably 1 mm to 6 mm, and more preferably 1.5. Mm~4 mm.

Further, in the invention of the present invention, the ridge portion 55 provided on the exit surface side may be formed into a shape other than the ridge portion 255 shown below. In other words, in the cross section orthogonal to the extending direction of each of the plurality of ridge portions 255, the apex (front end portion) 255a in the cross section of the ridge portion 255 is raised up to the point P on the contour line. The length of the contour line is set to L, and the axis passing through both end portions of the ridge portion 255 is set to the u-axis, and the inclination (absolute value) of the u-axis of the cross-sectional shape of the point portion P with respect to the ridge portion 255 is set. When it is α, it can also The shape is formed as follows: in the range of -0.20 < L < 0.20, the following formulas (26) and (27) are satisfied, 0 < α... (26)

At -0.65<L -0.20 range and 0.20 In the range of L<0.65, the following formulas (28) and (29) are satisfied,

At -1.00<L -0.65 range and 0.65 In the range of L < 1.00, the following formulas (30) and (31) are satisfied.

0<α.........(30)

In the light guide plate in which a plurality of ridge portions 255 having a cross-sectional shape in which α and Δα/ΔL satisfy the above-described conditions are formed on the light-emitting surface, light incident on the light incident surface of the light guide plate easily follows the ridge portion 255. The direction of extension extends. Therefore, when light propagates from the incident position of the light in the light guide plate, the diffusion of light is suppressed, so that crosstalk can be reduced. In addition, the L system sets the center in the u-axis direction to 0, and increases toward the right from the center (L>0), and decreases toward the left from the center (L<0).

The outer shape of the ridge portion 255 is preferably in the range of -0.20 < L < 0.20, and satisfies the following formula (32).

The outer shape of the ridge portion 255 is preferably -0.65 < L -0.20 range and 0.20 In the range of L < 0.65, the following formula (33) is satisfied.

The outer shape of the ridge portion 255 is preferably -1.00 < L -0.65 range and 0.65 In the range of L < 1.00, the following formula (34) is satisfied.

The outer shape of the ridge portion 255 is preferably such that when the width of the ridge portion 255 is w _a and the maximum height of the ridge portion 255 is h _a , the aspect ratio of the ridge portion 255 (h _a /w _a ) is 0.15 or more and less than 0.3.

Embodiments B1 to B5, which are examples of the outer shape of the ridge portion 255 as described above, will be described with reference to FIGS. 33 to 37. 33 to 37 are views showing an example of a cross-sectional shape orthogonal to the extending direction of the ridge portion. Fig. 33 shows an embodiment B1, Fig. 34 shows an embodiment B2, Fig. 35 shows an embodiment B3, Fig. 36 shows an embodiment B4, and Fig. 37 shows an embodiment B5. In FIGS. 33 to 37, the uv coordinate system is set by setting the direction orthogonal to the extending direction of the ridge portion 255 as the u-axis. In the uv coordinate system, the cross-sectional shape of the ridge portion 255 has both end portions 255b and 255b on the u-axis. In the uv coordinate system, the v-axis passes through the center between the ends 255b, 255b on the u-axis. In the embodiment shown in FIGS. 1 and 2, the u-axis direction is the Y-axis direction. Further, the v-axis direction is the Z-axis direction.

In the uv coordinate system, the cross-sectional shape of the ridge portion 255 satisfies the following formulas (35) to (40). Here, the position of the ridge portion 255 in the u-axis direction is w, and the inclination of the u-axis with respect to the cross-sectional shape of the ridge portion 255 at the position w is α. In the cross section orthogonal to the extending direction of the ridge portion 255, the length from the apex in the cross section of the ridge portion 255 to the point P on the contour line along the contour line is set to L. Δα/ΔL is the ratio of the amount of change in α to the amount of change in L. The angle α of the cross-sectional shape of the ridge portion 255 on the inclination α-position w (point P) is smaller than the angle at which the u-axis intersects (0 α 90).

In the u-axis direction, the length from the center O(0, 0) of the ridge portion 255 to the end portion 255b is set to 1. The position of the end portion 255b of the ridge portion 255 becomes w = -1, 1. The position w increases more toward the right from the center O (w>0), and decreases more toward the left from the center O (w<0). Further, in the v-axis direction, the height corresponding to the length of the end portion 255b from the center O of the ridge portion 255 is referred to as h _a . The position w is _a value normalized by the width w _{a of the} ridge portion 255, and the value of the position is expressed by _a ratio with respect to the width w _a .

The cross-sectional shape of the ridge portion 255 is in the first section A (the range of -0.20 < L < 0.20), and the following formulas (35) and (36) are satisfied.

0<α.........(35)

In the first section A, the cross-sectional shape of the ridge portion 255 is increased by the inclination α. In other words, the further away from the center O, the greater the inclination α.

The cross-sectional shape of the ridge portion 255 is in the second interval B (-0.65 < L -0.20 range and 0.20 The range of L < 0.65 satisfies the following formulas (37) and (38).

In the second section B, the cross-sectional shape of the ridge portion 255 is increased or not changed. In other words, the further away from the center O, the greater the inclination α or fixed.

The cross-sectional shape of the ridge portion 255 is in the third interval C (-1.00 < L -0.65 range and 0.65 The range of L < 1.00 satisfies the following formulas (39) and (40).

0<α.........(39)

In the third section C, the cross-sectional shape of the ridge portion 255 is increased by the inclination α. In other words, the further away from the center O, the greater the inclination α.

In the first interval A, Δα/ΔL may satisfy the following formula (41).

In the second interval B, Δα/ΔL may satisfy the following formula (42).

In the third section C, Δα/ΔL may satisfy the following formula (43).

38 is a view showing a portion of a cross-sectional shape of the ridge portion 255. When any two points on the outer shape of the ridge portion 255 are P ₁ and P ₂ , ΔL = L _{2 -} L ₁ (where L ₂ > L ₁ ), Δα = α _{2 -} α ₁ (where α ₂ α ₁ ). Where L ₁ is the position of the point P ₁ on the contour line, and α ₁ is the inclination of the point P ₁ (the angle of intersection with the u-axis). Similarly, L ₂ is the position of the point P ₂ on the contour line, and α ₂ is the inclination of the point P ₂ (the angle of intersection with the u-axis).

39 to 41 are views showing the relationship between the position L on the contour line of the cross-sectional shape of the ridge portion 255 and the inclination angle α. In FIGS. 39 to 41, the position L is indicated on the horizontal axis and the inclination angle α [degrees] is indicated on the vertical axis. On the horizontal axis, L = 0 indicates the center of the outline of the ridge portion 255. When the cross-sectional shape of the ridge portion 255 is L=0, the apex (front end portion 255a) of the ridge portion 255 is formed, and the inclination angle α=0. In the position L, the position of the end portion 255b in the width direction (u-axis direction) of the ridge portion 255 is L=1, which is represented by a ratio. L = 0.5 indicates the position between the center O and the end portion 255b. In Figure 39 to Figure 41, L is 0. L Tilt angle α, L is -1 L The value of the tilt angle α in the range of 0 becomes 0. L The return value of the value of 1.

Fig. 39 (a) shows an embodiment B1, Fig. 39 (b) shows an embodiment B2, Fig. 40 (a) shows an embodiment B3, Fig. 40 (b) shows an embodiment B4, and Fig. 41 shows an embodiment B5. The cross-sectional shape of the ridge portion 255 of the embodiments B1 to B5 is in the first section A, and the inclination angle α is increased. That is, the inclination angle α is larger as it goes away from the center O toward the end portion 255b (L=1) side.

The cross-sectional shape of the ridge portion 255 of the embodiment B1 is in the second section B, and the inclination angle α is increased or not changed. Specifically, the cross-sectional shape of the ridge portion 255 of the embodiment B1 is at 0.20. In the range of L < 0.60, the inclination angle α is fixed without being changed. The cross-sectional shape of the ridge portion 255 of the embodiment B1 is at 0.60. In the range of L < 0.65, the inclination angle α is increased.

The cross-sectional shape of the ridge portion 255 of the embodiment B2 to B5 is in the second section B, and the inclination angle α is increased. That is, the inclination angle α is larger as it goes away from the center O toward the end portion 255b (L=1) side.

The cross-sectional shape of the ridge portion 255 of the embodiments B1 to B5 is in the third section C, and the inclination angle α is increased. That is, the inclination angle α is larger as it goes away from the center O toward the end portion 255b (L=1) side.

Fig. 42 is a view showing the relationship between the line length L of the cross-sectional shape of the ridge portion 255 and Δα/ΔL. In Fig. 42, the line length L is indicated on the horizontal axis and Δα / ΔL is indicated on the vertical axis. In Figure 42, it indicates that L is 0. L △α/△L, L is -1 in the range of 1 L The value of Δα/ΔL becomes 0 in the range of 0 L The return value of the value of 1. Here, the line length L is represented by a ratio when the length along the contour line from the vertex (front end portion) 255a to the end portion 255b is "1".

The cross-sectional shape of the ridge portion 255 of the embodiments B1 to B5 is in the first section A, and Δα/ΔL is 60 or more and less than 160. The cross-sectional shape of the ridge portion 255 of the embodiments B1 to B5 is in the second section B, and Δα/ΔL is 0 or more and less than 30. The cross-sectional shape of the ridge portion 255 of the embodiments B1 to B5 is in the third section C, and Δα/ΔL is 10 or more and less than 110.

(aspect ratio)

The width w _{a of the} ridge portion 255 in the u-axis direction is generally smaller than the distance between the adjacent point light sources 61. The width w _{a is,} for example, 50 μm to 2000 μm, preferably 100 μm to 1000 μm, and more preferably 200 μm to 800 μm. h _a corresponds to the maximum height between the end portions 255b, 255b of the ridge portion 255. The aspect ratio (h _a /w _a ) of the ridge portion 255 is the ratio of the maximum height h _a to the width w _a of the ridge portion 255 . The aspect ratio of the ridge portion 255 is 0.15 or more and less than 0.30.

The cross-sectional shape of the plurality of ridge portions 255 is substantially the same between the ridge portions 255. However, the cross-sectional shape of each of the plurality of ridge portions 255 may be different as long as it satisfies the cross-sectional shape of the above formulas (35) to (40).

For example, the light guide plate including the above-described ridge portion 255 is not limited to a single layer structure, and may have a multilayer structure. In the present embodiment, the thickness of the light guide plate including the ridge portions 255 is defined as the thickness of the body portion. The distance between the top (front end portion) 255a of the plate thickness portion 255 of the main body portion and the back surface of the body portion is usually 0.5 mm to 8 mm, preferably 1 mm to 6 mm, and more preferably 1.5. Mm~4 mm.

Moreover, in the above-described embodiment, the light guide plate 50 integrally formed including the ridge portions 55 has been described. However, the light guide plate of the present invention is not limited to this. For example, a photopolymer method may be used, and a portion of the plate-shaped main portion which is a portion below the reference surface 51g shown in FIG. 4, that is, a portion above the reference surface 51g, that is, the ridge portion 55 may be formed.

Further, in the transmissive image display device 10 shown in FIG. 1, other optical members may be disposed between the light guide plate 50 and the transmissive image display portion 20 without departing from the gist of the present invention. The other optical member provided between the light guide plate 50 and the transmissive image display unit 20 includes, for example, a reflective polarized light separation plate, a light diffusion sheet, a microlens sheet, a lenticular lens sheet, and a gusset sheet.

10‧‧‧Transmissive image display device

20‧‧‧Transmission type image display unit

21‧‧‧Liquid Crystal Unit

22‧‧‧Polar plate

23‧‧‧Polar plate

30‧‧‧ surface light source device

50‧‧‧Light guide plate

50a‧‧‧ side

50b‧‧‧ side

51‧‧‧ Body Department

51a‧‧‧Outlet (1st side)

51b‧‧‧Back (2nd side)

51c‧‧‧ side (incident surface)

51d‧‧‧Side (incident surface)

52‧‧‧ lens department

52a‧‧‧ front end

52b‧‧‧ bottom

55‧‧‧ convex strip (lenticular lens)

60‧‧‧Light source department

61‧‧‧ Point light source

70‧‧‧Reflection Department

155‧‧‧Rocks (lenticular lens)

255‧‧‧ convex strip (lenticular lens)

X‧‧‧ axis

Y‧‧‧ axis

Z‧‧‧ axis

Fig. 1 is a schematic view showing a schematic configuration of a transmissive image display device according to an embodiment of a light guide plate to which the present invention is applied.

Fig. 2 is a plan view showing a state in which the light guide plate shown in Fig. 1 is viewed from the back side.

Fig. 3 is a side view showing a state in which the light guide plate shown in Fig. 1 is viewed from the light source side.

Fig. 4 is a view for explaining an example of a shape outside the ridge portion.

Fig. 5 is a view showing an example of a cross-sectional shape of a ridge portion.

Fig. 6 is a view showing an example of a cross-sectional shape of a ridge portion.

Fig. 7 is a view showing an example of a sectional shape of a ridge portion.

Fig. 8 is a view for explaining an example of a shape outside the lens portion.

Fig. 9 is a graph showing conditions for defining a shape other than the lens portion.

Fig. 10 is a view showing the shape of the outer portion of the lens portion.

Figs. 11(a) to 11(c) are diagrams showing the results obtained by observing the aspect ratio [h _IIa /w _IIa ] and the sharpness k _IIa of the lens portion formed by the ink jet method.

Fig. 12 is a view showing the range of the aspect ratio [h _IIa /w _IIa ] and the sharpness k _IIa of the lens portion formed by the ink jet method.

Fig. 13 is a graph showing the radius of curvature r _II of the tip end portion of the width w _IIa of the lens shape determined by the sharpness k _IIa and the aspect ratio [h _IIa /w _IIa ] shown in Fig. 12 .

Fig. 14 is a graph showing the radius of curvature r _II of the tip end portion of the width w _IIa of the lens shape determined by the sharpness k _IIa and the aspect ratio [h _IIa /w _IIa ] shown in Fig. 12 .

Fig. 15 is a graph showing the bottom angle γ _II of the lens shape determined by the sharpness k _IIa and the aspect ratio [h _IIa /w _IIa ] shown in Fig. 12.

Fig. 16 is a graph showing the bottom angle γ _II of the lens shape determined by the sharpness k _IIa and the aspect ratio [h _IIa /w _IIa ] shown in Fig. 12.

Fig. 17 is a graph showing conditions for defining a shape outside the lens portion.

Fig. 18 is a schematic view showing a simulation model.

Fig. 19 is a view showing the coverage distribution of the microlenses formed on the back side of the light guide plate used in the simulation.

Fig. 20 is a view showing the coverage distribution of the microlenses formed on the back side of the light guide plate used in the simulation.

Fig. 21 is a view showing the directivity characteristics of the point light source used in the simulation.

Fig. 22 is a graph showing the results of the simulation.

Fig. 23 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment A1).

Fig. 24 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment A2).

Fig. 25 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment A3).

Fig. 26 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment A4).

Fig. 27 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment A5).

Fig. 28 is a view showing a part of another cross-sectional shape of the ridge portion.

FIGS. 29(a) and 29(b) are views showing the relationship between the line length L and the inclination angle α in the other cross-sectional shapes of the ridge portions (embodiments A1 and A2).

FIGS. 30(a) and (b) are views showing the relationship between the line length L and the inclination angle α in the other cross-sectional shapes of the ridge portions (Embodiments A3 and A4).

Fig. 31 is a view showing the relationship between the length L of the line segment and the inclination angle α in the other cross-sectional shapes of the ridge portion (Embodiment A5).

Fig. 32 is a view showing the relationship between the line length L of the other cross-sectional shape of the ridge portion and Δα/ΔL.

Fig. 33 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment B1).

Fig. 34 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment B2).

Fig. 35 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment B3).

Fig. 36 is a view showing an example of another cross-sectional shape of the ridge portion (Embodiment B4).

37 is a view showing another example of the cross-sectional shape of the ridge portion (embodiment B5). figure.

Fig. 38 is a view showing a part of another cross-sectional shape of the ridge portion.

39(a) and (b) are views showing the relationship between the line length L and the inclination angle α in the other cross-sectional shapes of the ridge portions (embodiments B1 and B2).

40(a) and 40(b) are views showing the relationship between the line length L and the inclination angle α in the other cross-sectional shapes of the ridge portions (embodiments B3 and B4).

Fig. 41 is a view showing the relationship between the line length L of the other cross-sectional shape of the ridge portion and the inclination angle α (embodiment B5).

Fig. 42 is a view showing the relationship between the line length L of the other cross-sectional shape of the ridge portion and Δα/ΔL.

10‧‧‧Transmissive image display device

20‧‧‧Transmission type image display unit

21‧‧‧Liquid Crystal Unit

22‧‧‧Polar plate

23‧‧‧Polar plate

30‧‧‧ surface light source device

50‧‧‧Light guide plate

50a‧‧‧ side

50b‧‧‧ side

51‧‧‧ Body Department

51a‧‧‧Outlet

51b‧‧‧Back

51c‧‧‧ side

51d‧‧‧ side

52‧‧‧ lens department

55‧‧‧Rocks

60‧‧‧Light source department

61‧‧‧ Point light source

70‧‧‧Reflection Department

X‧‧‧ axis

Y‧‧‧ axis

Z‧‧‧ axis

Claims (4)

A light guide plate comprising: a plate-shaped body portion, comprising: a first surface extending in a direction and having a plurality of ridge portions arranged side by side in a direction substantially orthogonal to the one direction; and a second surface opposite to the first surface; and an incident surface which is a surface intersecting the first and second surfaces and is provided with light incident; and a plurality of lens portions formed in the main body portion The two surfaces protrude from the side opposite to the side on which the first surface is located when viewed from the second surface. The light guide plate of claim 1, wherein the ridge portion is a lenticular lens or a ridge. A surface light source device comprising: the light guide plate of claim 1 or 2; and a light source unit disposed to face the incident surface of the light guide plate to supply light to the incident surface. A transmissive image display device comprising: the light guide plate of claim 1 or 2; a light source portion disposed to face the incident surface of the light guide plate to supply light to the incident surface; and a transmission pattern The image display unit is provided on the first surface side of the light guide plate, and displays an image by illumination from the light emitted from the light guide plate.