JP2001210120A - Light guide plate, and backlight device, portable telephone set, electronic still camera, car navigation, or notebook personal computer using the plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide plate emitting light of uniform luminance, and a backlight device, a portable telephone set, an electronic still camera, a car navigation or a notebook personal computer which uses it. SOLUTION: A light guide plate 10 has an incidence face 1, a bottom face 2 and an emission face 3. The bottom face 2 is arranged in parallel with the incidence face 1, and has trenches 4 arranged with predetermined spaces in a direction DR1 away from the incidence face 1. The trench 4 whose cross section is a triangular shape having an almost perpendicular face to the bottom face 2 on the incidence face 1 side. The width of the trench 4 in the direction DR1 becomes wider as one goes away from the incidence face 1. The height of the trench 4 becomes higher as one goes away from the incidence face 1. The light guide plate 10 is used for the backlight device or the display part for the portable telephone set, the electronic still camera, the car navigation or the notebook personal computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate used in a planar light source device used as a backlight of various display devices, and more particularly to a so-called edge in which a light source is arranged on at least one side end surface of the light guide plate. The present invention relates to a light guide plate suitable for a light type planar light source device.

[0002]

2. Description of the Related Art An edge light type planar light source device has one end face 1 of a light guide plate 190 as shown in a plan view of FIG.
The light source 6 is disposed on the side 93 and the light from the light source 6
The light enters the light guide plate 190 from 3 and is emitted by the cone 191 formed in a substantially conical shape so that the traveling direction is changed from a direction perpendicular to the plane of FIG. . Then, the light enters a display panel (not shown) provided in a direction parallel to the paper surface of FIG. 17 and above the light guide plate 190, and is used as a backlight of various display devices.

[0003] The cone 191 formed on the light guide plate 190 is formed so as to gradually increase in size in a direction DR1 away from the end face 193. this is,
This is to make the luminance of the light emitted from the light guide plate 190 uniform. That is, if a cone of the same size is formed in the direction DR1 away from the end face 193, the light incident from the end face 193 does not reach the part far from the light source 6, and the light near the light source 6 emits bright light. 6, light with low brightness is emitted from a portion far from the light guide plate 190.
In order to emit light with uniform brightness from the entire surface, a cone 191 whose size gradually increases in the direction DR1 away from the end face 193 is formed.

Further, a direction DR1 away from the end face 193
The cones 191 are arranged at equal intervals in a direction DR2 perpendicular to the direction. The cone 191 has a direction DR1 moving away from the end surface 193 and a direction DR orthogonal to the direction DR1.
2 is formed such that the center distances of adjacent cones are equal.

[0005]

However, the conventional light guide plate is formed such that the center distances of adjacent cones are equal in the direction DR1 away from the end face 193 and in the direction DR2 perpendicular to the direction DR1. Cone 191
There is a region 192 in which is not formed. as a result,
The light emitted from the light guide plate 190 has a direction DR1 moving away from the end surface 193 and a direction DR orthogonal to the direction DR1.
Second, there is a problem that light areas and dark areas are alternately present, and when viewed as a whole, light with uneven brightness is emitted.

Accordingly, the present invention solves the above problem and provides a light guide plate capable of emitting light with uniform luminance, and a backlight device, a mobile phone, an electronic still camera, a car navigation system, or a notebook personal computer using the same. The purpose is to:

[0007]

Means for Solving the Problems and Effects of the Invention According to the first aspect of the present invention, there is provided a light incident surface, a light exit surface substantially perpendicular to the incident surface, and a light exit surface substantially perpendicular to the incident surface. A light guide plate of a plate-like body including a bottom surface provided to face the
The bottom surface is parallel to the incident surface and includes a plurality of grooves cut in the direction of the emission surface, and each of the plurality of grooves is substantially perpendicular to the bottom surface and formed on a first surface formed on the incident surface side. The light guide plate includes a surface and a second surface that guides a part of the light transmitted through the first surface to the emission surface and guides other light in a direction away from the incident surface.

[0008] In the light guide plate according to the first aspect,
Light incident from the incident surface is transmitted through the first surface constituting the groove, and is partially guided to the emission surface by the second surface, and other light is guided in a direction away from the incident surface to pass through the light guide plate. proceed. Therefore, according to the first aspect of the present invention, light can be guided to a region far from the incident surface, and a decrease in luminance in a region far from the incident surface can be prevented.

According to a second aspect of the present invention, in the light guide plate according to the first aspect, the plurality of grooves are formed such that the distance between the grooves decreases as the distance from the incident surface increases. In the light guide plate according to the second aspect, the light incident on the light guide plate is incident on the groove as the distance from the incident surface increases, and the light is guided to the emission surface more frequently.

Therefore, according to the second aspect of the present invention, light with uniform luminance can be emitted from the light exit surface of the light guide plate.
According to a third aspect of the present invention, in the light guide plate according to the first aspect, the distance from the bottom surface of the first surface to the emission surface becomes longer as the distance from the incident surface increases.

[0011] In the light guide plate according to the third aspect,
As the light that enters the light guide plate moves away from the entrance surface,
The frequency of incidence on the groove and guiding to the exit surface increases. Therefore, according to the third aspect of the present invention, light with uniform luminance can be emitted from the emission surface of the light guide plate. The invention according to claim 4 includes an incident surface on which light is incident, an emission surface of light substantially orthogonal to the incident surface, and a bottom surface substantially orthogonal to the incident surface and provided to face the emission surface. A plate-shaped light guide plate, wherein the bottom surface is parallel to the incident surface and includes a plurality of grooves cut in the direction of the emission surface, and the plurality of grooves are substantially perpendicular to the bottom surface and the incident surface. A first groove formed of a first surface formed on the side and a second surface for guiding a part of the light transmitted through the first surface to the exit surface and guiding other light in a direction away from the incident surface; A second groove that guides a part of the light to the light exit surface and guides the other light in a direction away from the light incident surface, the second groove including at least the third surface on the light incident surface side. It is a light guide plate formed in number.

[0012] In the light guide plate according to the fourth aspect,
Light incident from the incident surface travels in a direction away from the incident surface while being incident on the first groove and partially guided to the exit surface,
The light enters the second groove. Then, more light is guided to the emission surface by the second groove than by the first groove. Therefore, according to the invention set forth in claim 4, more light can be guided to the emission surface in a region far from the incidence surface where the light intensity decreases. As a result, light with uniform luminance can be emitted from the light guide plate.

According to a fifth aspect of the present invention, in the light guide plate according to the fourth aspect, the distance from the bottom surface of the first surface to the exit surface becomes longer as the distance from the entrance surface increases. is there. In the light guide plate according to the fifth aspect, the light incident on the light guide plate is incident on the first groove as the distance from the incident surface increases, and the first groove is formed while increasing the frequency of being guided to the exit surface. Pass through the region, and enter the second groove. Then, more light is guided to the emission surface by the second groove.

Therefore, according to the invention described in claim 5, more light can be guided to the emission surface as the distance from the incidence surface increases. As a result, light with uniform brightness as a whole can be emitted even if the light intensity decreases as the distance from the incident surface increases. According to a sixth aspect of the present invention, there is provided a light guide plate according to any one of the first to fifth aspects, a light source provided on an incident surface side of the light guide plate, and a light guide plate provided on a bottom surface side of the light guide plate. And a diffusion sheet provided on the light emitting surface side of the light guide plate, and a diffusion sheet provided on the light emitting surface side of the lens sheet.

In the backlight device according to the sixth aspect, light emitted from the light source enters the light guide plate from the incident surface of the light guide plate, and travels while being reflected by the bottom surface, the emission surface, and the groove. Then, the light refracted by the groove is reflected by the diffuse reflection sheet, refracted by the groove again, exits from the exit surface as light with uniform brightness, and enters the lens sheet. The light incident on the lens sheet is condensed and incident on the diffusion sheet, scattered by the diffusion sheet, and emitted as light with uniform brightness.

Therefore, according to the invention described in claim 6, light without uneven brightness can be emitted from the backlight device. According to a seventh aspect of the present invention, there is provided a light guide plate according to any one of the first to fifth aspects, a light source provided on an incident surface side of the light guide plate, and a light guide plate provided on a bottom surface side of the light guide plate. And a display panel provided on the emission surface side of the light guide plate.

In the portable telephone according to the present invention, the light emitted from the light source enters the light guide plate from the incident surface of the light guide plate, and travels while being reflected by the bottom surface, the emission surface, and the groove. Then, the light refracted by the groove is reflected by the diffuse reflection sheet, refracted by the groove again, exits from the exit surface as light with uniform brightness, and enters the display panel. Therefore, according to the invention described in claim 7, characters and the like without uneven brightness can be displayed on the display unit of the mobile phone.

The invention according to claim 8 provides the light guide plate according to any one of claims 1 to 5, a light source provided on an incident surface side of the light guide plate, and a bottom surface side of the light guide plate. Is an electronic still camera including a diffuse reflection sheet provided on a light guide plate and a display panel provided on an emission surface side of a light guide plate.

In the portable telephone according to the present invention, the light emitted from the light source enters the light guide plate from the incident surface of the light guide plate, and travels while being reflected by the bottom surface, the emission surface, and the groove. Then, the light refracted by the groove is reflected by the diffuse reflection sheet, refracted by the groove again, exits from the exit surface as light with uniform brightness, and enters the display panel. Therefore, according to the invention described in claim 8, a moving image without luminance unevenness can be displayed on the display unit of the electronic still camera, and a desired photograph can be taken while viewing the moving image.

According to a ninth aspect of the present invention, there is provided a light guide plate according to any one of the first to fifth aspects, a light source provided on an incident surface side of the light guide plate, and a bottom surface side of the light guide plate. Is a car navigation system including a diffuse reflection sheet provided on a light guide plate and a display panel provided on an emission surface side of a light guide plate.

In the car navigation system according to the ninth aspect, the light emitted from the light source enters the light guide plate from the incident surface of the light guide plate, and travels while being reflected by the bottom surface, the emission surface, and the groove. Then, the light refracted by the groove is reflected by the diffuse reflection sheet, refracted by the groove again, exits from the exit surface as light with uniform brightness, and enters the display panel. Therefore, according to the ninth aspect of the present invention, it is possible to display a map or the like without uneven brightness on the display unit of the car navigation, and to reach the target place without error by looking at the map.

The invention according to claim 10 is the first invention.
A light guide plate according to any one of claims 1 to 5, a light source provided on an incident surface side of the light guide plate, a diffuse reflection sheet provided on a bottom surface side of the light guide plate, and an emission surface side of the light guide plate. A notebook computer including a display panel provided.

In the notebook personal computer according to the tenth aspect, the light emitted from the light source enters the light guide plate from the incident surface of the light guide plate, and travels while being reflected by the bottom surface, the emission surface, and the groove. Then, the light refracted by the groove is reflected by the reflection sheet, is refracted by the groove again, exits from the exit surface as light with uniform brightness, and enters the display panel. Therefore, according to the tenth aspect of the present invention, it is possible to display characters, images, and the like without uneven brightness on the display unit of the notebook computer, and to perform various operations while seeing the clear characters, images, and the like. .

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. Referring to FIG. 1, a light guide plate 10 according to the present invention has a substantially plate-like shape, and includes a light incident surface 1 and a bottom surface 2.
And a light exit surface 3. On the bottom surface 2, grooves 4 having a triangular cross-section parallel to the incident surface 1 are formed at predetermined intervals.

A light source 6 is provided on the incident surface 1 side.
Is covered with a light collector 7 so that light emitted from the light source 6 is incident on the incident surface 1 of the light guide plate 10. Light source 6
Are arranged along the incident surface 1, for example, five to six. A diffuse reflection sheet 8 is provided on the bottom surface 2 side of the light guide plate 10.
Is provided. Light emitted from the light source 6 and incident on the light guide plate 10 from the incident surface 1 is reflected by the bottom surface 2 and the exit surface 3, travels in the light guide plate 10 in the direction DR1 away from the incident surface 1, and enters the groove 4. The incident light is partly refracted and guided to the light exit surface 3, partly transmitted in the DR1 direction, and partly reflected toward the diffuse reflection sheet 8 side. Then, the light reflected to the diffuse reflection sheet 8 side is reflected by the diffusion reflection sheet 8,
Again, the light is refracted by the groove 4 and guided to the emission surface 3. Therefore,
The groove 4 functions to guide the light incident from the incident surface 1 to the emission surface 3 and to guide the light in the DR1 direction.
Has a function of changing the light incident from the incident surface 1 and exiting the light guide plate 10 from the groove 4 toward the exit surface 3. Further, the diffuse reflection sheet 8 reflects light and also has a function of diffusing light at the time of the reflection.

The thickness of the light guide plate 10 is about 1.0 mm.
The planar structure of the light guide plate 10 will be described with reference to FIG. The groove 4 is composed of grooves 41, 42, 43, 44, and 45 arranged at predetermined intervals in a direction DR1 away from the light source 6, and each groove has a width in the DR1 direction.
1, the grooves 42,... And
The width of the groove 41 in the DR1 direction is 0.1 mm, and the width of the groove 42 is
Of the groove 43 is 0.15 mm.
The width in the R1 direction is 0.2 mm, the width of the groove 44 in the DR1 direction is 0.25 mm, and the width of the groove 45 in the DR1 direction is 0.3 mm.

Referring to FIG. 2B, the cross-sectional shape along the line AB in FIG. 2A will be described. The height of each groove from the bottom surface 2 in the direction of the light exit surface 3 gradually increases in the direction DR1 away from the light incident surface 1, and the height of the groove 41 is
0.1 mm, the height of the groove 42 is 0.15 mm, the height of the groove 43 is 0.2 mm, the height of the groove 44 is 0.25 mm, the height of the groove 45 Is 0.3mm
It is. In each of the grooves 41, 42, 43, 44, and 45, a surface perpendicular to the bottom surface 2 is formed on the incident surface 1 side. The distance L between the grooves is constant, and a specific example of L is 0.2 to 0.4 mm.

Referring to FIG. 3, details of the grooves formed in light guide plate 10 will be described. Referring to FIG.
The groove 43 includes a surface 431 having a vertex CDEF formed on the incident surface 1 side, and a surface 432 having a vertex DEGH. The surface 431 is formed perpendicular to the bottom surface 2. Referring to FIG. 3B, when light LB1 incident from incident surface 1 is perpendicularly incident on surface 431 of groove 43, light LB1 is transmitted through surface 431 and refracted by surface 432 to become light LB3. It passes through the groove 43. The light LB2 incident from the incident surface 1
Is refracted at the surface 431 of the groove 43 and reaches the diffuse reflection sheet 8. Then, the light is reflected by the diffuse reflection sheet 8 and the grooves 43 are formed.
The light is refracted by the surface 432 and is guided to the emission surface 3 as light LB4. Therefore, the groove 43 receives the light LB1 incident from the incident surface 1.
In the direction DR1 away from the incident surface 1 and guide the light LB2 to the exit surface 3, and a surface 431 perpendicular to the bottom surface 2 directs light incident on the groove 43 away from the incident surface 1 in a direction DR1. The surface 432 functions to guide the light that has entered the groove 43 to the emission surface 3. Among known light guide plates, there is a light guide plate in which the surface 432 is formed on the incident surface 1 side. However, in this case, most of the light incident on the groove is reflected on the exit surface 3 side and moves away from the incident surface 1. Light can hardly be guided in the direction DR1. The groove 43 of the present application is different from such a known groove, and has both a function of guiding incident light to the emission surface 3 and a function of guiding light in a direction away from the incident surface 1.

Another groove 4 formed on the bottom surface 2 of the light guide plate 10
The grooves 43 described above are also used for 1, 42, 44 and 45.
It has the same structure as. Therefore, the light incident on the light guide plate 10 from the incident surface 1 is reflected by the grooves 41, 42, 43, 4.
The light is guided to the direction DR1 away from the incident surface 1 while a part of the light is guided to the emission surface 3 by the parts 4 and 45. This allows
Bright light can be emitted from a region far from the light source 6.

Referring to FIG. 4, the surface formed on the side of incidence surface 1 constituting groove 43 is a surface 4 formed perpendicular to bottom surface 2.
In general, the surface 433 formed on the side of the incident surface 1 is not limited to the direction
What is necessary is just to form an angle θ having a range of 0 degrees. This is the same for the other grooves 41, 42, 44, 45. Therefore, “substantially perpendicular to the bottom surface” described in the claims of the present application means that the direction of the normal to the bottom surface 2 is 10 to 2
It refers to making an angle of 0 degrees.

Referring to FIG. 5, light emitted from light source 6 enters light guide plate 10 from incident surface 1, travels in the direction of DR1 while being reflected by bottom surface 2 and exit surface 3, and Groove 4
1, 42, 44 and 45. Then, the light LB5 that has entered the groove 41, the light LB6 that has entered the groove 42, the light LB7 that has entered the groove 44, and the light LB8 that has entered the groove 45 are guided to the emission surface 3 as described above. In the light guide plate 10, the length of the groove formed on the bottom surface 2 of the surface formed on the side of the incident surface 1 in the direction from the bottom surface 2 to the exit surface 3 increases as the distance from the incident surface 1 increases (each groove). The height of the triangle having the cross-sectional shape becomes higher.) Therefore, even if the light intensity decreases as the distance from the incident surface 1 increases, the ratio of light entering the groove increases, and the ratio of light guided to the exit surface 3 also increases. As a result, light with uniform brightness can be emitted from the emission surface 3 of the light guide plate 10.

The light guide plate according to the present invention is not limited to the light guide plate 10 having the planar structure shown in FIG. 1, but may be a light guide plate 20 shown in FIG. The light guide plate 20 is obtained by replacing the groove 4 of the light guide plate 10 with the groove 5.
Is the same as The planar structure of the light guide plate 20 will be described with reference to FIG. The grooves 5 are grooves 51, 52 arranged at predetermined intervals in a direction DR1 away from the light source 6,
53, 54, 55, 56, and 57, and DR1 of each groove 51, 52, 53, 54, 55, 56, 57
The width in the direction is the same as 0.1 mm.

With reference to FIG. 7B, the cross-sectional shape taken along the line AB in FIG. 7A will be described. Each groove 5
The height of the bases 1, 52, 53, 54, 55, 56, 57 from the bottom surface 2 to the exit surface 3 is the same as 0.4 mm.
The distance between the grooves gradually decreases in the direction DR1 away from the incident surface 1, and the distance L1 between the grooves 51 and 52 is 0.3
5 mm, and the interval L2 between the groove 52 and the groove 53 is 0.3
mm, and the interval L3 between the groove 53 and the groove 54 is 0.25
mm, and the interval L4 between the groove 54 and the groove 55 is 0.2 m
m, and the interval L5 between the groove 55 and the groove 56 is 0.15 m
m, and the interval L6 between the groove 56 and the groove 57 is 0.1 mm
It is.

Also, as described with reference to FIG. 4, the light guide plate 20 also
A groove having an angle in the range of 0 degrees formed on the incident surface 1 may be used. The light guide plate according to the present invention may be the light guide plate 30 shown in FIG. The light guide plate 30 is the same as the light guide plate 10 except that the groove 4 of the light guide plate 10 shown in FIG. The light guide plate 30 has a surface perpendicular to the bottom surface 2 disposed on the incident surface 1 side, a groove 9 having a triangular cross-sectional shape is formed in a region near the incident surface 1, and a groove 11 having a different cross-sectional shape from the groove 9 is incident. The light guide plate is formed in a region far from the surface 1.

The planar structure of the light guide plate 30 will be described with reference to FIG. The grooves 9 are grooves 91, 92, 9 arranged at predetermined intervals in the direction DR1 away from the light source 6.
3, and the groove 11 is formed by grooves 111 and 112 arranged at a predetermined interval in the direction of DR1. Each groove 9
The width in the DR1 direction of 1, 92, 93 is the same as 0.1 mm, and the width of each groove 111, 112 in the DR1 direction is 0.1 mm.
Same as 2 mm.

Referring to FIG. 9B, a cross-sectional shape taken along line AB in FIG. 9A will be described. Each groove 9
The height of the bases 1, 92, 93 from the bottom surface 2 to the exit surface 3 is the same as 0.1 mm, and the height of the grooves 111, 112 from the bottom surface 2 to the exit surface 3 is also 0.1 mm. Is the same. The distance L1 between the grooves 91, 92, 93 is 0.3 to
It is the same as 0.4 mm, and the distance L3 between the grooves 111 and 112 is the same as 0.2 mm. The groove 9 and the groove 11
The distance L2 between the groove 93 and the groove 111 existing at the boundary of
0.2 to 0.3 mm.

Referring to FIG. 10, the details of the grooves formed in light guide plate 30 will be described. Referring to FIG. 10A, a groove 112 has a vertex IJKM formed on the incident surface 1 side.
1121 having a vertex and a surface 112 having a vertex JKNP
2 The surface 1121 and the surface 1122 are formed at a predetermined angle with the bottom surface 2. FIG.
(B), light LB9 incident from the incident surface 1
Is incident on the surface 1121 of the groove 112, and a part of the
The light is reflected as light LB10 in the direction of FIG. And part is refracted and surface 1
It passes through 121 and reaches surface 1122. The light that reaches the surface 1122 is refracted by the surface 1122 and is converted into light LB11 by the groove 11.
Pass 2 Further, the light LB12 incident on the groove 112
Is refracted by the surface 1121 and reaches the diffuse reflection sheet 8, is reflected by the diffuse reflection sheet 8, is refracted by the surface 1122 of the groove 112, and is guided to the emission surface 3 as light LB13. Accordingly, the groove 112 also functions to guide the incident light to the emission surface 3 also on the surface 1121 formed on the incident surface 1 side.
It fulfills the function of leading to Due to such a function, in the light guide plate 30, the groove 9 is formed in a region near the incident surface 1 and the groove 11 is formed in a region far from the incident surface 1.
As a result, even if the intensity of the incident light is reduced in the region where the groove 11 is formed, more light can be guided to the emission surface 3 than in the region where the groove 9 is formed. Uniform light can be emitted from the emission surface 3.

The groove formed in a region far from the incident surface 1 of the light guide plate 30 is not limited to the groove 9, but may be the groove 12 shown in FIG. The groove 12 is formed on the incident surface 1 side, includes a surface 121 forming a predetermined angle with the bottom surface 2, and a surface 122 forming a predetermined angle with the bottom surface 2 on a side opposite to the surface 121, and has a trapezoidal cross-sectional shape. It is a groove. Also in the groove 12, the light incident on the groove 12 can be guided to the emission surface 3 by the surfaces 121 and 122.

As shown in FIG. 12, a groove formed in a region far from the incident surface 1 of the light guide plate 30 generally has a surface 120 forming an acute angle φ with the normal direction of the bottom surface 2. The cross-sectional shape is not particularly limited as long as the groove is included on the side. Also, in the light guide plate 30, as described with reference to FIG. 4, the groove having the surface forming an angle in the range of 10 to 20 degrees with the normal direction of the bottom surface 2 on the incident surface 1 side is formed by the groove 9. Alternatively, it may be formed.

The light guide plate according to the present invention may be a light guide plate 40 shown in FIG. The planar structure of the light guide plate 40 includes grooves 91, 92, 9 of the light guide plate 30 shown in FIG.
3 is replaced by grooves 131, 132, and 133, and the rest is the same as the light guide plate 30. Grooves 131, 132, 1
Reference numeral 33 denotes a groove which becomes wider in the direction DR1 away from the incident surface 1 (see FIG. 13A). And the groove 131
Is 0.1 mm, and the width of the groove 132 is 0.15
mm, and the width of the groove 133 is 0.2 mm.

In the sectional structure of the light guide plate 40, as shown in FIG. 13B, the heights of the grooves 131, 132, and 133 increase as the distance from the entrance surface 1 increases. And
The height of the groove 131 is 0.1 mm, the height of the groove 132 is 0.15 mm, and the height of the groove 133 is 0.2 m
m. The interval between the grooves is the same as that described in FIG.

By forming a groove whose height gradually increases in a region near the incident surface 1, the direction DR moving away from the incident surface 1 while guiding the light incident from the light source 6 to the emission surface 3.
1, and in a region far from the entrance surface 1, more light can be guided to the exit surface 3 by the grooves 111 and 112 even if the intensity is reduced. Thereby, light with uniform brightness can be emitted from the emission surface 3.

Also in the light guide plate 40, a groove having the cross-sectional shape described with reference to FIGS. Further, the light guide plate according to the present invention has a structure shown in FIG.
The light guide plate 50 shown in FIG. In the light guide plate 50, the grooves 141, 142, 1 having the same width in the DR1 direction are provided.
43, 144 and 145 are formed at predetermined intervals. And D of each groove 141, 142, 143, 144, 145
The width in the R1 direction is 0.1 mm (see FIG. 14A).

Referring to FIG. 14B, a cross-sectional shape taken along the line AB in FIG. 14A will be described.
Bottom surface 2 of each groove 141, 142, 143, 144, 145
And the height in the direction of the exit surface 3 is the same as 0.1 mm. In addition, each groove 141, 142, 143, 144, 14
The distance L4 between 5 is the same as 0.3 mm. Light guide plate 5
0, the angle between the groove 141, the groove 142,... And the surface formed on the incident surface 1 side of each groove and the normal direction of the bottom surface 2 increases as the distance from the incident surface 1 increases. That is, the groove 141 has a surface having an angle of 0 degrees with the normal direction of the bottom surface 2 on the incident surface 1 side, and the groove 142 has a surface having an angle of 15 degrees with the normal direction of the bottom surface 2 having the incident surface. One side has a groove 143
Has a surface at an angle of 30 degrees with the normal direction of the bottom surface 2 on the incident surface 1 side, and the groove 144 has a surface at an angle of 45 degrees with the normal direction of the bottom surface 2 on the incident surface 1 side. And the groove 145 is
The incident surface 1 has a surface having an angle of 60 degrees with the normal line direction. By using the grooves 141, 142, 143, 144, and 145, it is possible to increase the ratio of light incident on the grooves to the emission surface 3 as the distance from the incidence surface 1 increases. As a result, light with uniform brightness can be emitted from the emission surface 3.

Referring to FIG. 15, incident surface 1 of light guide plate 10
A light source 6 is disposed on the side, and a diffuse reflection sheet 8 is provided on the bottom surface 2 side of the light guide plate 10. A lens sheet 15, a diffusion sheet 16, and a liquid crystal panel (LCD) 17 are provided on the light exit surface 3 side of the light guide plate 10. The liquid crystal panel 17 includes a liquid crystal 171 and two polarizing plates 170, 1.
A voltage applied to electrodes (not shown) having a cross-sectional structure sandwiched by 70 and arranged in a matrix is set to ON / OF.
By performing F, light in a desired region can be transmitted or blocked. Thereby, characters, images, and the like can be displayed.
The point light source 6, the light guide plate 10, the diffuse reflection sheet 8, the lens sheet 15, and the diffusion sheet 16 constitute a backlight device.

The light emitted from the light source 6 enters the light guide plate 10 from the incident surface 1, travels through the light guide plate 10 as described above, and emits light having uniform brightness from the emission surface 3 of the light guide plate 10. Emit. The light emitted from the light guide plate 10 is collected by the lens sheet 15 in the direction of the diffusion sheet 16 and enters the diffusion sheet 16. The light that has entered the diffusion sheet 16 is scattered by the diffusion sheet 16 and enters the liquid crystal panel 17. As a result, the brightness of light becomes uniform in each part of the liquid crystal panel 17, and display without display unevenness becomes possible.

Referring to FIG. 16, light guide plate 1 described above is described.
0 is used for the display unit 181 of the mobile phone 180, for example. By using the light guide plate 10, for example, the characters “mobile phone” can be displayed on the display unit 181 of the mobile phone 180 without uneven brightness. Not only characters but also images and the like can be displayed without uneven brightness. Further, in the present invention, the light guide plate 10 is provided not only on a mobile phone but also on a display unit of an electronic still camera.
May be used. In an electronic still camera, a moving image can be displayed on a display unit, and one scene of the moving image can be edited as a photograph. Therefore, the user views the moving image and edits the desired scene if any.
By using the light guide plate 10 as a display unit of an electronic still camera, a moving image can be viewed in a state without luminance unevenness, and the edited photograph has no luminance unevenness.
You can edit beautiful photos.

Further, in the present invention, the light guide plate 1
0 may be used for car navigation and notebook computers. By using it for car navigation, you can see a clear map, and if the driver of the car looks at the car navigation display at a glance, you can see the current driving point, reach the destination safely and accurately it can. In addition, by using a notebook computer, clear characters and images can be seen, eyestrain can be prevented, and work can be performed efficiently.

The light guide plates 20, 30, 40, and 50 can also be applied to the applications described with reference to FIGS.

[Brief description of the drawings]

FIG. 1 is a perspective view of a light guide plate according to the present invention.

FIG. 2 is a plan view and a cross-sectional view of the light guide plate of FIG.

FIG. 3 is a diagram illustrating details of a groove formed in the light guide plate of FIG. 1;

FIG. 4 is a diagram illustrating a modified example of a cross-sectional shape of a groove formed in the light guide plate of FIG.

FIG. 5 is a diagram for explaining a light traveling mechanism in the light guide plate shown in FIG.

FIG. 6 is a perspective view of another light guide plate according to the present invention.

7 is a plan view and a sectional view of the light guide plate of FIG.

FIG. 8 is a perspective view of still another light guide plate according to the present invention.

9 is a plan view and a cross-sectional view of the light guide plate of FIG.

FIG. 10 is a diagram illustrating details of a groove formed in the light guide plate of FIG. 8;

FIG. 11 is a diagram illustrating a modification of the cross-sectional shape of the groove formed in the light guide plate of FIG.

FIG. 12 is a diagram illustrating a cross-sectional shape applicable to a groove formed in the light guide plate of FIG.

FIG. 13 is still another plan view and cross-sectional view of the light guide plate according to the present invention.

FIG. 14 is still another plan view and a sectional view of the light guide plate according to the present invention.

FIG. 15 is a diagram illustrating a mechanism of a backlight using a light guide plate.

FIG. 16 is a diagram illustrating an application example of the light guide plate.

FIG. 17 is a diagram illustrating a conventional problem.

[Explanation of symbols]

1 entrance plane, 2 low plane, 3 exit plane, 4, 5,
9, 11, 12, 41, 42, 43, 44, 45, 5,
1, 52, 53, 54, 55, 56, 57, 91, 9
2, 93, 111, 112, 120, 131, 132,
133, 141, 142, 143, 144, 145
Groove, 6 light source, 7 light collector, 8 diffuse reflection sheet, 10, 20, 30, 40, 50 light guide plate, 15
Lens sheet, 16 diffusion sheet, 17 liquid crystal panel, 120, 121, 122 planes, 170 liquid crystal, 171 polarizing plate, 180 mobile phone, 181
Display unit, 431, 432, 433

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hidetoshi Ito 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Inside Sanyo Electric Co., Ltd. (72) Inventor Masato Yamada 2-chome, Keihanhondori, Moriguchi-shi, Osaka No. 5 F-term (reference) in Sanyo Electric Co., Ltd. 2H038 AA55 BA06 5G435 AA03 BB12 EE27 FF03 FF06 FF08 GG24 LL07 LL14

Claims (10)

[Claims] 1. A plate-like shape including an incident surface on which light is incident, an emission surface of light substantially orthogonal to the incident surface, and a bottom surface substantially orthogonal to the incident surface and provided to face the emission surface. A light guide plate of a body, wherein the bottom surface includes a plurality of grooves parallel to the incident surface and cut in a direction of the emission surface, and each of the plurality of grooves is substantially perpendicular to the bottom surface. A first surface formed on the incident surface side, and a second surface that guides a part of light transmitted through the first surface to the emission surface and other light in a direction away from the incident surface. A light guide plate comprising a surface. 2. The light guide plate according to claim 1, wherein the plurality of grooves are formed such that a distance between the grooves decreases as the distance from the incident surface increases. 3. The light guide plate according to claim 1, wherein a distance from the bottom surface of the first surface to the emission surface increases as the distance from the incidence surface increases. 4. A plate-like shape including an incident surface on which light is incident, an exit surface for light substantially perpendicular to the incident surface, and a bottom surface substantially perpendicular to the incident surface and provided opposite to the exit surface. A light guide plate of a body, wherein the bottom surface includes a plurality of grooves parallel to the incident surface and cut in a direction of the emission surface; and the plurality of grooves are substantially perpendicular to the bottom surface. A first surface formed on the incident surface side, and a second surface for guiding a part of the light transmitted through the first surface to the emission surface and guiding other light in a direction away from the incident surface. And a second groove including at least a third surface on the side of the incident surface that guides a part of the light to the exit surface and guides other light in a direction away from the incident surface, A light guide plate having a predetermined number of the first grooves formed on the incident surface side. 5. The light guide plate according to claim 4, wherein a distance from the bottom surface of the first surface to the light exit surface increases as the distance from the light incident surface increases. 6. The light guide plate according to claim 1, a light source provided on the incident surface side of the light guide plate, and a light source provided on the bottom surface side of the light guide plate. A backlight device comprising: a diffuse reflection sheet; a lens sheet provided on the light exit surface side of the light guide plate; and a diffusion sheet provided on the light exit surface side of the lens sheet. 7. The light guide plate according to claim 1, a light source provided on the light incident surface side of the light guide plate, and a light source provided on the bottom surface side of the light guide plate. A mobile phone comprising: a diffuse reflection sheet; and a display panel provided on the light exit surface side of the light guide plate. 8. The light guide plate according to claim 1, a light source provided on the incident surface side of the light guide plate, and a light source provided on the bottom surface side of the light guide plate. An electronic still camera comprising: a diffuse reflection sheet; and a display panel provided on the light exit surface side of the light guide plate. 9. The light guide plate according to claim 1, a light source provided on the incident surface side of the light guide plate, and a light source provided on the bottom surface side of the light guide plate. A car navigation system including: a diffuse reflection sheet; and a display panel provided on the light exit surface side of the light guide plate. 10. The light guide plate according to claim 1, a light source provided on the incident surface side of the light guide plate, and a light source provided on the bottom surface side of the light guide plate. A notebook personal computer comprising: a diffuse reflection sheet; and a display panel provided on the light exit surface side of the light guide plate.