KR20070114752A - Light guide plate, light source unit, display panel unit and electronic device - Google Patents

Abstract

In a light guide plate (23), light is introduced into a light transmitting plate member from an incidence plane (24). The introduced light goes out from a rear plane of the light transmitting plate member by effects of a prism (25). Thus, on the rear plane of the light transmitting plate member, surface emission is achieved. At this time, when the light projected on the incidence plane (24) has brightness nonuniformity, a flat area (26) is aligned with a dark area. Therefore, the light can be guided to the prism (25) while being reflected by the flat area (26). At the same time, outside the flat area (26), the light is diffusely reflected by effects of a light scattering structure (27). A part of the diffusely reflected light can be guided to on an extended line (33) of the flat area (26). Thus, sufficient light is guided to the prism (25) on the extended line (33) of the flat area (26). As a result, dark line is prevented from being generated on the light guide plate (23), and generation of the brightness nonuniformity can be eliminated. Brightness distribution as uniform as possible can be provided on the light guide plate (23).

Description

Light guide plate, light source unit, display panel unit, and electronic device {LIGHT GUIDE PLATE, LIGHT SOURCE UNIT, DISPLAY PANEL UNIT AND ELECTRONIC DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic devices such as, for example, cellular phone terminal devices, and more particularly to light guide plates, light source units, and display panel units incorporated in such electronic devices.

The mobile phone terminal device includes a liquid crystal monitor (LCD) panel unit that partitions a display screen. In a so-called front light type LCD panel unit, the light guide plate faces the LCD panel surface. A plurality of rows of prisms are formed on the surface of the light guide plate. The light guide member faces the end face of the light guide plate. A pair of light sources, for example, face the side of the light guide member.

Light irradiated from the light source is incident on the light guide plate by the function of the light guide member. The incident light is irradiated toward the LCD panel by the function of the prism of the light guide plate. The irradiated light is irradiated toward the outside of the cellular phone terminal device by the function of the reflecting plate bonded to the back of the LCD panel. In this way, text or graphics are displayed on the display screen.

In such a mobile phone terminal device, so-called dark lines are generated in the light guide plate due to processing errors of the light guide member. The dark lines cause luminance unevenness on the display screen of the LCD panel. In particular, in the front panel LCD panel unit, since the light guide plate is disposed between the user's eyes and the LCD panel, the luminance unevenness of the display screen should be particularly avoided.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-141918

[Patent Document 2] Japanese Patent Application Laid-Open No. 11-232918

[Patent Document 3] Japanese Unexamined Patent Application Publication No. 10-227918

[Patent Document 4] Japanese Patent Application Laid-Open No. 10-48629

This invention is made | formed in view of the said real thing, and an object of this invention is to provide the light guide plate, the light source unit, the display panel unit, and an electronic device which can implement | achieve a uniform luminance distribution as much as possible.

In order to achieve the above object, according to the first aspect of the present invention, an incident surface defined on the end face of the light transmissive plate member, a plurality of rows of prisms formed on the surface of the light transmissive plate member at positions away from the incident surface, the incident surface and the prism Between a flat region defined on the surface of the light transmissive plate member along an arbitrary straight line between the incident surface and the prism, and formed on the surface of the light transmissive plate member outside the flat region, and having an irregular reflection surface of light. A light guide plate having a light scattering structure having is provided.

In such a light guide plate, light is introduced into the light transmitting plate member from the incident surface. The introduced light is emitted from the back of the light transmitting plate member by the function of the prism. In this way, surface light emission is implement | achieved on the back surface of the light transmitting plate member. At this time, when luminance unevenness occurs in the light irradiated onto the incident surface, the flat region is aligned with respect to the dark region. Thus, light can be directed to the prism while reflecting in the flat region. At the same time, light is diffusely reflected by the function of the light scattering structure outside the flat region. Some of the diffusely reflected light may be directed over an extension line of the flat region. In this way, sufficient light is induced to the prism on the extension line of the flat region. As a result, generation of dark lines is avoided in the light guide plate. The occurrence of so-called brightness unevenness is avoided. In the light guide plate, the luminance distribution as uniform as possible can be realized.

In such a light guide plate, the light scattering structure may have a grinding mark. The polishing trace may be formed by, for example, sand paper. Similarly, the light scattering structure may be provided with a curved prism extending toward the flat region while being curved. In addition, the light scattering structure may include protrusions protruding from the surface of the light transmitting plate member. Light scattering may occur in the light guide plate by the function of these grinding marks, curved prisms, and projections.

In another light guide plate, the light scattering structure may include a first projection projecting from the surface of the light transmissive plate member and a second projection projecting from the surface of the light transmissive plate member at a position away from the flat region than the first projection. At this time, the boundary surface of the first projection and the light transmitting plate member may be defined larger in the direction orthogonal to an arbitrary straight line than the boundary surface of the second projection and the light transmitting plate member. In such a light guide plate, the light introduced from the incident surface is diffusely reflected by the functions of the first and second projections. Since the first projection is largely defined in a direction orthogonal to an arbitrary straight line as compared with the second projection, the light is dispersed while being greatly spread in the in-plane direction of the light guide plate as compared with the second projection. In addition, the first protrusion is disposed closer to the flat region than the second protrusion. As a result, a part of the light dispersed in the first protrusion can be induced relatively more on the extension line of the flat region than the second protrusion. In this way, the luminance distribution as uniform as possible can be realized in the light guide plate. Such a light guide plate can be used particularly effectively when the light quantity difference is relatively large, for example, between a flat region and a region adjacent to the flat region among regions other than the flat region.

In another light guide plate, the light scattering structure has a first projection projecting from the surface of the light transmitting plate member as described above, and a second projection projecting from the surface of the light transmitting plate member at a position away from the flat region than the first projection. Also good. At this time, the boundary surface of the first projection and the light transmitting plate member may be defined smaller in the direction orthogonal to an arbitrary straight line than the boundary surface of the second projection and the light transmitting plate member. In such a light guide plate, since the first projection is defined small in a direction orthogonal to an arbitrary straight line as compared with the second projection, light is dispersed while spreading smaller in the in-plane direction of the light guide plate than the second projection. On the other hand, the first projection is disposed closer to the flat region than the second projection. As a result, a part of the light scattered in the first protrusion is induced on the extension line of the flat region. On the other hand, in the second projection, light is dispersed while being greatly spread in the in-plane direction of the light guide plate as compared with the first projection. Even if the second protrusion is disposed at a position away from the flat region relative to the first protrusion, a part of the light scattered in the second protrusion may be induced to a relatively large extent over the extension line of the flat region. In the light guide plate, the luminance distribution as uniform as possible can be realized. Such a light guide plate can be used particularly effectively when the light quantity difference is relatively large, for example, between a flat region and a region away from the flat region among regions other than the flat region.

In the light scattering structure provided with the first and second projections, the interface area of the first projection and the light transmitting plate member may be larger than the interface area of the second projection and the light transmitting plate member. In such a light guide plate, the light introduced from the incident surface is diffusely reflected by the functions of the first and second projections. Since the interface area is larger than that of the second projection in the first projection, the light diffuses in the in-plane direction of the light guide plate as compared with the second projection. In addition, the first protrusion is disposed closer to the flat region than the second protrusion. As a result, a portion of the light dispersed in the first projections can be relatively increased to the extension line of the flat region as compared with the second projections. In this way, the luminance distribution as uniform as possible can be realized in the light guide plate. Such a light guide plate can be used particularly effectively when the light quantity difference is relatively large, for example, between a flat region and a region close to the flat region among regions other than the flat region.

In the light scattering structure provided with the first and second projections, the interface area between the first projection and the light transmitting plate member may be smaller than the interface area between the second projection and the light transmitting plate member. In the light guide plate as described above, the light is diffused in the first projection in a smaller direction in the in-plane direction of the light guide plate than in the second projection. On the other hand, the first projection is disposed closer to the flat region than the second projection. As a result, a part of the light scattered in the first protrusion is induced on the extension line of the linear region. Similarly, in the second projection, light diffuses and spreads in the in-plane direction of the light guide plate as compared with the first projection. Even if the second projection is disposed at a position away from the flat region relative to the first projection, the light scattered in the second projection is relatively induced on the extension line of the linear region. In the light guide plate, the luminance distribution as uniform as possible can be realized. Such a light guide plate can be used particularly effectively when the light quantity difference is relatively large, for example, between a flat region and a region away from the flat region among regions other than the flat region.

In the light scattering structure provided with the first and second projections, the interface shape between the first and second projections and the light transmitting plate member may be defined in common. At the same time, intrinsic reference lines may be defined in the first and second protrusions in the shape of the boundary plane crossing the boundary plane. At this time, the intersection angle between the reference line of the first projection and the arbitrary straight line may be larger than the intersection angle between the reference line of the second projection and the arbitrary straight line. In such a light guide plate, based on the crossing angle larger than the crossing angle of the second protrusion, the light is dispersed while spreading along the extension line of the linear region in the in-plane direction of the light guide plate. In addition, the first protrusion is disposed closer to the flat region than the second protrusion. As a result, a part of the light dispersed in the first protrusion can be induced relatively more on the extension line of the flat region than the second protrusion. In this way, the luminance distribution as uniform as possible can be realized in the light guide plate as described above.

In another light guide plate, the light scattering structure protrudes from the surface of the light transmissive plate member at a position away from the flat region than the first projection group, which is composed of a plurality of first protrusions protruding from the surface of the light transmissive plate member. You may be provided with the 2nd protrusion group comprised by several 2nd protrusion. At this time, the protrusions of the first protrusion group may be arranged to be denser than the protrusions of the second protrusion group. Further, the first projection group is arranged closer to the flat region than the second projection group. As a result, relatively more light is dispersed in the first projection group than in the second projection group. Some of the light scattered in the first projection group may be induced relatively more on the extension line of the flat region than the second projection group. In this way, the same uniform luminance distribution as possible in the light guide plate can be realized as described above.

According to the second aspect of the present invention, an incident surface defined on the end face of the light transmitting plate member, a plurality of rows of prisms formed on the surface of the light transmitting plate member at a position away from the incident surface, and along an arbitrary straight line between the incident surface and the prism A light guide plate comprising a flat region defined on the surface of the light transmissive plate member and a plurality of spheres disposed on the surface of the light transmissive plate member outside the flat region between the incident surface and the prism, causing light scattering. do. In such a light guide plate, light incident from an incident surface may be scattered by the function of a sphere. As described above, the luminance distribution as uniform as possible can be realized in the light guide plate.

The above light guide plate may be incorporated in the light source unit, for example. The light source unit includes a light source, a light guide member that reflects light emitted from the light source and outputs it from the emission surface, a light transmission plate member opposing the light guide member, and a cross section of the light transmission plate member so as to oppose the emission surface of the light guide member. A plurality of prisms formed on the surface of the light transmissive plate member at a position away from the incident surface and reflecting light irradiated from the light guide member, and a light transmissive plate member along an arbitrary straight line between the incident surface and the prism A light scattering structure may be provided that has a flat region defined on the surface of the surface of the light transmissive plate, and is formed on the surface of the light transmitting plate member outside the flat region while being disposed between the incident surface and the prism, and has a boundary surface that diffuses light.

In such a light source unit, light output from the exit surface of the light guide member is introduced into the light transmitting plate member at the entrance surface. The introduced light exits from the back of the light transmitting plate member by the function of the prism. In this way, surface light emission is implement | achieved on the back surface of the light transmitting plate member. At this time, if a luminance nonuniformity arises in the light irradiated from the emission surface of the light guide member based on the processing error of the light guide member, the flat area is aligned with respect to the dark area. Thus, light can be directed to the prism while reflecting in the flat region. At the same time, light is diffusely reflected by the function of the light scattering structure outside the flat region. Some of the diffusely reflected light may be directed over an extension line of the flat region. In this way, sufficient light is induced to the prism on the extension line of the flat region. As a result, generation of dark lines is avoided in the light guide plate. So-called occurrence of luminance unevenness is avoided. The occurrence of so-called brightness unevenness is avoided. In the light guide plate, as uniform a luminance distribution as possible can be realized.

Similarly, the above light guide plate may be incorporated in a display panel unit such as a liquid crystal monitor (LCD) panel unit. The display panel unit includes a light source, a light guide member that reflects light emitted from the light source and outputs the light from the emission surface, a light transmission plate member facing the light guide member, and a cross section of the light transmission plate member, A plurality of rows of prisms formed on the opposing incidence surface and the surface of the light transmitting plate member at positions away from the incidence surface to reflect light irradiated from the light guide member, and the light transmitting plate along an arbitrary straight line between the incidence surface and the prism; A light-scattering structure having a flat region defined on the surface of the member, a boundary surface disposed between the incidence surface and the prism and formed on the surface of the light transmissive plate member outside the flat region to diffusely reflect light, and the surface of the light transmissive plate member What is necessary is to provide the display panel which opposes. In this display panel unit, the luminance distribution as uniform as possible can be realized as described above.

Similarly, the above light guide plate may be incorporated in an electronic device such as a cellular phone terminal device. The electronic device is defined in a housing, a light source embedded in the housing, a light guide member that reflects light emitted from the light source and outputs it from an emission surface, a light transmitting plate member facing the light guide member, and a cross section of the light transmitting plate member. An incident surface opposite to the exit surface of the light guide member, a plurality of rows of prisms formed on the surface of the light transmitting plate member at a position away from the entrance surface to reflect light emitted from the light guide member, and an arbitrary A light scattering structure having a flat region defined on the surface of the light transmissive plate member along a straight line, a boundary surface formed between the incident surface and the prism and formed on the surface of the light transmissive plate member outside the flat region, and having diffused reflection of light; A display panel may be provided that faces the surface of the light transmissive plate member and faces the window opening defined by the housing. According to such an electronic device, the luminance distribution as uniform as possible can be realized in the display screen exposed in the window opening of the housing.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view schematically showing an embodiment of an electronic apparatus according to an embodiment of the present invention, that is, the appearance of a mobile phone terminal device.

2 is an exploded perspective view schematically showing the configuration of the LCD panel unit of the present invention.

3 is a partial plan view schematically showing the configuration of the LCD panel unit of the present invention;

4 is a cross-sectional view taken along the line 4-4 of FIG. 3, schematically showing the configuration of the LCD panel unit of the present invention.

5 is a graph showing luminance distribution of an LCD panel unit according to a comparative example.

6 is a graph showing the luminance distribution of the LCD panel unit according to the specific example.

FIG. 7 is a cross-sectional view for explaining a light scattering structure corresponding to FIG. 4. FIG.

8 is a partial plan view schematically illustrating a configuration of a light guide plate according to one embodiment.

9 is a partial plan view schematically showing the configuration of a light guide plate according to one modification;

10 is a partial plan view schematically showing the configuration of a light guide plate according to another modification;

11 is a partial plan view schematically showing the configuration of a light guide plate according to another modification;

12 is a partial plan view schematically illustrating a configuration of a light guide plate according to another modification.

13 is a partial plan view schematically showing the configuration of a light guide plate according to another modification;

14 is a partial plan view schematically showing the configuration of a light guide plate according to another modification;

15 is a partial plan view schematically showing the configuration of a light guide plate according to another modification;

16 is a partial plan view schematically showing the configuration of a light guide plate according to another modification;

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring an accompanying drawing.

1 schematically shows an example of an embodiment of an electronic device according to an embodiment of the present invention, that is, the appearance of a mobile phone terminal device 11. This mobile phone terminal device 11 includes a telephone receiver 12 and a telephone receiver 13. The receiver 13 can rotate relative to the talker 12 around the axis of rotation 14. The talker 12 has a first housing, ie a body housing 15. The handset 13 has a second housing, that is, a display housing 16. The main body housing 15 and the display housing 16 may be molded from a reinforced resin material, for example.

A printed board (not shown) is embedded in the main body housing 15. As is well known, a processing circuit such as a CPU (central processing unit), a memory, or the like is mounted on a printed board. An input button 17 such as an on-hook button, an off-hook button, or a dial key is embedded on the surface of the talker 12. In accordance with the operation of the input button 17, the CPU executes various processes.

On the surface of the display housing 16, a flat panel display panel unit such as a liquid crystal monitor (LCD) panel unit 18 is incorporated. A window opening, that is, a display opening 19, is defined on the surface of the display housing 16. The LCD panel unit 18 exposes a flat display screen in the display opening 19. Various texts and graphics are displayed on the display screen of the LCD panel unit 18 in accordance with the processing operation of the CPU.

As shown in Fig. 2, the LCD panel unit 18 is configured of a so-called front light type. That is, the LCD panel unit 18 includes a rectangular LCD panel 21. The LCD panel 21 forms a liquid crystal cell between a pair of glass substrates, for example. Each liquid crystal cell corresponds to a pixel of a display screen. Such LCD panel 21 is configured in a so-called reflective type. The reflecting plate 22 is adhered to the back surface of the glass substrate. For example, a display control circuit board (not shown) may be disposed on the rear surface of the reflecting plate 22.

The LCD panel unit 18 has a light guide plate 23 facing the surface of the LCD panel 21 on a flat rear surface. The light guide plate 23 may be composed of a rectangular light transmitting plate member. The light guide plate 23 defines four cross sections orthogonal to the back surface. Each cross section consists of a flat surface. One end surface of the light guide plate 23 functions as the incident surface 24.

On the surface of the light guide plate 23, a plurality of rows of prisms 25, 25... Are formed at positions away from the incident surface 24. Each prism 25 extends parallel to the incident surface 24 at the surface of the light guide plate 23. The prism 25 is formed in the display screen area of the LCD panel unit 18. In the display screen area, as the surface of the light guide plate 23 moves away from the incident surface 24, the surface of the light guide plate 23 approaches the rear surface. In this way, in the display screen area, the thickness of the light guide plate 23 gradually decreases as it falls from the incident surface 24. The light guide plate 23 may be molded from a resin material such as plastic.

The flat region 26 is defined on the surface of the light guide plate 23 along an arbitrary straight line between the incident surface 24 and the prism 25. The flat area 26 is disposed outside the display screen area of the LCD panel unit 18. In the flat region 26, a flat surface defined in parallel to the rear surface of the light guide plate 23 is partitioned. Here, any straight line extends in the vertical direction, for example orthogonal to the prism 25. In this way, the flat region 26 extends in the vertical direction perpendicular to the incident surface 24.

On the surface of the light guide plate 23, a light scattering structure 27 is further formed between the incident surface 24 and the prism 25. The light scattering structure 27 has an interface for diffusely reflecting light. The light scattering structure 27 is formed outside of the flat region 26. Similar to the flat region 26, the light scattering structure 27 is disposed outside the display screen region. The light scattering structure 27 is provided with fine grinding marks. In this way, the light scattering structure 27 scatters the light incident from the incident surface 24. The surface roughness Ra of the light scattering structure 27 may be set to, for example, about 0.08 μm.

The light guide member 28 opposes the incident surface 24 of the light guide plate 23. The light guide member 28 opposes the light guide plate 23 from an exit surface defined in parallel to the incident surface 24 of the light guide plate 23. The light guide member 28 has a reflective surface 29 facing the incident surface 24 of the light guide plate 23 in the light guide member 28. A plurality of rows of prisms (not shown) are formed on the reflecting surface 29. The prism extends in the vertical direction orthogonal to the surface of the light guide plate 23. Prisms are placed at minute intervals.

A pair of light sources 31 and 31 oppose the side of the light guide member 28. The light guide member 28 is disposed between the light sources 31 and 31. The light source 31 includes, for example, an LED (light emitting diode) 32. Each LED 32 faces the side of the light guide member 28. The LED 32 may irradiate, for example, white light toward the side of the light guide member 28.

In this case, a scene for example displaying a graphic on the display screen of the LCD panel unit 18 is assumed. Light is irradiated into the light guide member 28 from the LED 32 of the light source 31. The LED 32 functions as a so-called point light source. As shown in FIG. 3, the irradiated light is irradiated toward the incident surface 24 of the light guide plate 23 by the function of the prism of the reflective surface 29. The light guide member 28 outputs light from the emission surface. In this way, the light guide member 28 functions as a so-called line light source. At this time, in the light guide member 28, the amount of outgoing light traveling straight from the exit surface to the flat region 26 decreases due to the prism processing error of the reflection surface 29.

In the light guide plate 23, light incident straight from the incident surface 24 is irradiated toward the surface of the LCD panel 21 by the function of the prism 25. Similarly, light incident on the incident surface 24 at a predetermined angle of incidence is irradiated toward the surface of the LCD panel 21 by the function of the prism 25. In this way, the light guide plate 23 functions as a so-called surface light source. In addition, the LED 32, that is, the light source 31, the light guide member 28, and the light guide plate 23 function as the light source unit of the present invention.

4, the light incident toward the light scattering structure 27 of the light guide plate 23 is scattered by the function of the light scattering structure 27. As is apparent from FIG. 3, light is dispersed in the in-plane direction of the light guide plate 23. The scattered light is directed from the flat region 26 to the linear regions 33 and 33 extending in the vertical direction orthogonal to the prism 25. The guided light is irradiated toward the surface of the LCD panel 21 by the function of the prism 25.

Light emitted from the light guide plate 23 passes through the LCD panel 21. The transmitted light is reflected by the reflector 22. The reflected light passes through the light guide plate 23 and is irradiated to the outside from the display opening 19. At this time, a graphic may be displayed on the display screen of the LCD panel unit 18 by the function of the liquid crystal cell or the color filter of the LCD panel 21.

As described above, in the mobile phone terminal device 11 described above, due to prism processing error of the reflecting surface 29, luminance unevenness occurs in the irradiated light. The flat area 26 is positioned in the dark area. Thus, light can be directed to prism 25 while reflecting off flat region 26. At the same time, light is dispersed outside the flat region 26 by the function of the light scattering structure 27. Some of the scattered light can be directed to the linear region 33. In this way, sufficient light is guided to the prism 25 in the linear region 33. In the linear region 33, the amount of light is increased more than now. In the light guide plate 23, generation of dark lines is avoided. The occurrence of so-called brightness unevenness is avoided. In the display screen of the LCD panel unit 18, the luminance distribution as uniform as possible can be realized.

In response to the manufacturing of the light guide plate 23 described above, a polishing process may be performed outside the flat region 26. For example, sand paper may be used for the polishing treatment. Prior to the polishing process, the position of the flat region 26 is specified on the light guide plate 23. The light guide member 28 is prepared in advance corresponding to the positional specification of the flat region 26. The outgoing light of the light guide member 28 is observed. The flat area 26 is positioned in the area where the emitted light is small. Simulation may be performed corresponding to observation of the emitted light of the light guide member 28. In general, the characteristics of the outgoing light of the light guide member 28 are determined based on the precision of the prism of the reflecting surface 29. The precision of the prism depends on the precision of the mold used in the manufacture of the light guide member 28. Therefore, as long as the same metal mold | die is used, the same characteristic is anticipated for the exit light of the light guide member 28. FIG.

The present inventor has verified the effect of the LCD panel unit 18 as described above. In response to the verification, specific examples and comparative examples were prepared. In the LCD panel unit 18 according to the embodiment, the above-described flat region 26 and the light scattering structure 27 are formed in the light guide plate 23. The flat region 26 is disposed in a region where the emitted light is small. In the LCD panel unit according to the comparative example, the formation of the flat region and the light scattering structure is omitted. The other structure was formed similarly to the LCD panel unit which concerns on a specific example. Here, in the embodiment and the comparative example, a light guide plate having a size of 2 inches was used. In Examples and Comparative Examples, luminance was measured. The luminance was measured on a straight line defined by a predetermined distance from the incident surface 24 within the display screen area. A straight line was defined parallel to the prism 25. In response to the measurement, a luminance meter was used.

As shown in Fig. 5, in the LCD panel unit according to the comparative example, a large increase or decrease in luminance was observed in the width direction of the light guide plate parallel to the prism. For example, it was confirmed that so-called dark lines generate | occur | produce in the position about 10 mm from both end surfaces of a light guide plate. In positions other than a dark line, the brightness | luminance comparatively higher than the position of a dark line was measured. It was confirmed that luminance unevenness occurred in the display screen of the LCD panel unit according to the comparative example.

On the other hand, as shown in FIG. 6, in the LCD panel unit 18 according to the specific example, a substantially constant luminance was measured in most of the width direction of the light guide plate 23. That is, it was confirmed that the occurrence of large increase and decrease of luminance at the position in the width direction of the light guide plate 23 is avoided. In the LCD panel unit 18 according to the specific example, although the total amount of light decreases to some extent as compared with the comparative example, it has been confirmed that generation of dark lines is eliminated. On the display screen of the LCD panel unit 18, it was confirmed that occurrence of luminance nonuniformity was avoided. On the display screen of the LCD panel unit 18, it was confirmed that as uniform a luminance distribution as possible was realized.

In general, the human eye is insensitive to light reduction of the entire LCD panel unit. For example, it is difficult for the human eye to perceive a decrease in the amount of light unless the LCD panels are arranged in a comparative view. On the other hand, the human eye is sensitive to the luminance unevenness that occurs in the display screen of the LCD panel unit. Therefore, even if the amount of light is slightly reduced in the entire display screen of the LCD panel unit 18, the projection of the display screen of the LCD panel unit 18 can be significantly improved as compared with the case where luminance unevenness occurs.

Here, as shown in FIG. 7, in general, when light is incident at an incident angle α of 30 ° or less, for example, the light is irradiated toward the surface of the LCD panel 21 effectively by the function of the prism 25. Therefore, when the thickness T of the light guide plate 23 is set to 1, the length L of the light scattering structure 27 defined in the direction away from the incident surface 24 is required to be set to 3 square roots or less. In this way, for example, light incident at an angle of incidence greater than 30 ° can be led to the linear region 33 as much as possible by the function of the light scattering structure 27. Incident angle α is defined as an angle parallel to one plane parallel to the surface or the back surface of the light guide plate 23.

In addition, as shown in FIG. 8, the light scattering structure 27 of the light guide plate 23 is provided with a plurality of rows of curved prisms 34, 34... You may also do it. Each curved prism 34 may be constituted by a curve extending in an arc shape toward the prism 25 from the incident surface 24 side. The curve approaches the incidence surface 24 as it faces the flat region 26. The shape of each curved prism 34 may be defined in common in each flat region 26.

The light incident from the incident surface 24 is scattered by the function of the curved prism 34. Some of the scattered light can be directed to the linear region 33 relatively simply. In the linear region 33 sufficient light is directed to the prism 25. In the display screen of the LCD panel unit 18, the luminance distribution as uniform as possible can be realized. Hereinafter, the same reference numerals are attached to structures and structures equivalent to those of the above-described embodiment.

In response to the manufacture of the light guide plate 23, the first resin plate including the prism 25 and the second resin plate including the curved prism 34 may be molded. The first and second resin plates may be molded separately based on the mold. Thereafter, the first and second resin plates may be bonded together. In this way, the light guide plate 23 is formed. In addition, the curved shape of the curved prism 34 may be adjusted according to the light amount of the linear region 33.

In addition, as shown in FIG. 9, the light scattering structure 27 may include a plurality of protrusions 35, 35... That project from the surface of the light guide plate 23 instead of the prism 34. Each projection 35 may be arranged at equal intervals, for example. Each protrusion 35 may protrude in the shape of a polygonal pyramid, for example, from the surface of the light guide plate 23. Here, each protrusion 35 protrudes, for example in a square pyramid shape. The interface shape of each protrusion 35 and the light guide plate 23 may be defined in common. Since each projection 35 is configured in the shape of a square pyramid, the interface is defined by a quadrilateral.

In the light guide plate 23, light incident from the incident surface 24 is scattered by the function of the projection 35. Light is dispersed in the in-plane direction of the light guide plate 23. Some of the light that is scattered can be directed to the linear region 33 relatively simply. In the linear region 33 sufficient light is directed to the prism 25. In the display screen of the LCD panel unit 18, the luminance distribution as uniform as possible can be realized. Corresponding to the formation of the projections 35, a manufacturing method similar to the above-described prism 34 may be performed.

In addition, as shown in FIG. 10, in the light scattering structure 27, the protrusion 35 has a first region 36 protruding from the surface of the light guide plate 23 and a flat region (which is flatter than the first protrusion 36). The second projection 37 may protrude from the surface of the light guide plate 23 at a position away from 26. The first protrusion 36 is disposed in proximity to the flat region 26. Here, the boundary surface of the first projection 36 and the light guide plate 23 is defined larger in the direction orthogonal to the flat region 26 than the boundary surface of the second projection 37 and the light guide plate 23. At the same time, the area of the boundary surface of the first protrusion 36 is set larger than the area of the boundary surface of the second protrusion 37. The interface may be defined small in the direction orthogonal to the flat region 26 as it faces the first projection 36 from the first projection 36. Similarly, the interface surface area may be set gradually smaller from the first projection 36 toward the second projection 37.

In the light guide plate 23, light incident from the incident surface 24 is scattered by the functions of the first and second protrusions 36 and 37. In the first protrusion 36, light is dispersed while being greatly spread in the in-plane direction of the light guide plate 23 as compared with the second protrusion 37. In addition, the first protrusion 36 is disposed closer to the flat region 26 than the second protrusion 37. As a result, a part of the light dispersed in the first protrusion 36 may be led to a relatively large amount up to the linear region 33 as compared with the second protrusion 37. In the display screen of the LCD panel unit 18, the luminance distribution as uniform as possible can be realized. Such a light guide plate 23 can be used particularly effectively when the light quantity difference between the linear region 33 and a region close to the linear region 33 among regions other than the linear region 33 is relatively large.

In addition, as shown in FIG. 11, the interface between the first protrusion 36 and the light guide plate 23 is smaller in the direction parallel to the flat region 26 than the interface between the second protrusion 37 and the light guide plate 23. It may be prescribed. At this time, the interface shape between the first and second protrusions 36 and 37 and the light guide plate 23 may be defined in common, for example. In other words, the boundary surfaces of the first and second protrusions 36 and 37 may be defined as similar shapes to each other. In this case, the boundary surface area may be set to be gradually smaller as the second protrusion 37 is directed from the first protrusion 36.

In such a light guide plate 23, since a common shape is defined at the interface between the first and second protrusions 36 and 37, light is distributed in the same area in the in-plane direction of the light guide plate 23. As shown in FIG. Since an area larger than the boundary surface of the second protrusion 37 is set at the boundary surface of the first protrusion 36, much light can be dispersed in the first protrusion 36. In addition, the first protrusion 36 is disposed closer to the flat region 26 than the second protrusion 37. As a result, a part of the light dispersed in the first protrusion 36 may be induced in the linear region 33 relatively more than the second protrusion 37. In this manner, as described above, the luminance distribution as uniform as possible can be realized on the display screen of the LCD panel unit 18.

In addition, as shown in FIG. 12, in the light scattering structure 27, the 1st protrusion 36 and the 2nd protrusion 37 may be arrange | positioned contrary to the arrangement of FIG. At this time, the boundary surface of the first protrusion 38 and the light guide plate 23 may be defined smaller in the direction orthogonal to the flat region 26 than the boundary surface of the second protrusion 39 and the light guide plate 23. At the same time, the boundary surface area of the first protrusion 38 may be set larger than the boundary surface area of the second protrusion 39. Here, the boundary surface may be largely defined in the direction orthogonal to the flat region 26 as the first projection 38 faces the second projection 39. In this way, the interface area is gradually set larger as the first projection 38 faces the second projection 39.

In the light guide plate 23, light incident from the incident surface 24 is scattered by the function of the first protrusion 38. In the first protrusion 38, light diffuses in a small direction in the in-plane direction of the light guide plate 23. In addition, the first protrusion 38 is disposed closer to the flat region 26 than the second protrusion 39. As a result, the light scattered from the first protrusion 38 can be induced relatively much in the linear region 33. On the other hand, in the second projection 39, light is dispersed while being greatly spread in the in-plane direction of the light guide plate 23 as compared with the first projection 38. Even if the second protrusion 39 is disposed at a position away from the flat region 26 relative to the first protrusion 38, a part of the light scattered in the second protrusion 37 may be induced in the linear region 33 relatively. . In this way, the luminance distribution as uniform as possible can be realized on the display screen of the LCD panel unit 18 as described above. Such a light guide plate 23 can be used particularly effectively when the light quantity difference between the linear region 33 and a region apart from the linear region 33 among regions other than the linear region 33 is relatively large.

In addition, as shown in FIG. 13, in the light scattering structure 27, when each reference line 35 defines a reference line 41 that crosses an interface with the light guide plate 23, the reference line of the first protrusion 42 is defined. The crossing angle α between the 41 and the flat region 26 is set larger than the crossing angle β of the reference line 41 of the second protrusion 43 and the flat region 26. At this time, the boundary surface shape of each protrusion 35 is defined in common, for example. The reference line 41 is uniquely defined in the shape of the interface. Since the interface is defined as a quadrilateral, the reference line 41 is defined as a diagonal of the quadrangle. Here, what is necessary is just to set the crossing angle (beta) of the 2nd protrusion 43 to 0 degrees. As the first projection 42 faces the second projection 43, the crossing angle between the reference line 41 and the flat region 26 may be set to be gradually smaller.

In the light guide plate 23, light incident from the incident surface 24 is scattered by the functions of the first and second protrusions 42 and 43. Based on the crossing angle α, the light diffuses in the first projection 42 toward the linear region 33 in the in-plane direction of the light guide plate 23. In addition, the first protrusion 42 is disposed close to the flat region 26. As a result, a portion of the light scattered from the first protrusion 42 may be induced in the linear region 33 relatively more than the second protrusion 43. In this manner, as described above, the luminance distribution as uniform as possible can be realized on the display screen of the LCD panel unit 18.

In addition, as shown in FIG. 14, the light scattering structure 27 is farther from the flat region 26 than the first projection group 44 composed of the plurality of projections 35 and the first projection group 44. The 2nd protrusion group 45 comprised from the some processus | protrusion 35 in a position may be provided. The first protrusion group 44 is disposed close to the flat region 26. The protrusions 35 of the first protrusion group 44 are densely arranged as compared with the protrusions 35 of the second protrusion group 45. That is, the arrangement density of the projections 35 is set larger in the first projection group 44 than in the second projection group 45. In this case, the boundary surface shapes of the protrusions 35 in the first and second protrusion groups 44 and 45 may be defined in common.

In the light guide plate 23, light is scattered in the first and second protrusion groups 44 and 45 to the same area in the in-plane direction of the light guide plate 23. Since the projections 35 of the first projection group 44 are densely arranged as compared with the projections 35 of the second projection group 45, the projections 35 of the first projection group 44 are relatively larger in the first projection group 44 than the second projection group 45. Much light is dispersed. In addition, the first projection group 44 is disposed closer to the flat region 26 than the second projection group 45. As a result, a part of the light dispersed in the first protrusion group 44 may be relatively induced in the linear region 33 as compared with the second protrusion group 45. In this manner, as described above, the luminance distribution as uniform as possible can be realized on the display screen of the LCD panel unit 18.

In addition, as shown in FIG. 15, in the light scattering structure 27, the protrusion 35 may protrude, for example, in a hemispherical shape from the surface of the light guide plate 23. Each protrusion 35 may be arranged at equal intervals, for example, as described above. The interface surface shape of each protrusion 35 and the light guide plate 23 may be defined in common. The light incident from the incident surface 24 is scattered by the function of this light scattering structure 27. Light is dispersed in the in-plane direction of the light guide plate 23. Some of the scattered light can be induced relatively simply in the linear region 33. In the display screen of the LCD panel unit 18, the luminance distribution as uniform as possible can be realized.

In addition, as shown in FIG. 16, the light guide plate 23a may include a plurality of spheres 46 disposed between the incident surface 24 and the prism 25 instead of the light scattering structure 27. The sphere 46 is disposed outside of the flat region 26. The sphere 46 may be made of, for example, a metallic sphere having a gloss on its surface. The sphere 46 may be fixed to the surface of the light guide plate 23a based on, for example, a resin adhesive 47. By the function of this sphere 46 the light incident from the incident surface 24 can be scattered. As described above, the luminance distribution as uniform as possible can be realized on the display screen of the LCD panel unit 18.

In addition, the light guide plate 23a includes a first sphere disposed closer to the flat region 26 and a second sphere disposed on the surface of the light guide plate 23a at a position farther from the flat region 26 than the first sphere. It may be comprised. The first sphere may be defined larger than the second sphere, for example. The size of the spheres 46 should just be set small gradually toward a 2nd sphere from a 1st sphere. In addition, the light guide plate 23a is a first sphere group composed of a plurality of spheres 46 and a second sphere group composed of a plurality of spheres 46 arranged farther from the flat region 26 than the first sphere group. It may be provided. That is, the spheres 46 of the first sphere group may be denser than the spheres 46 of the second sphere group.

In the light guide plates 23 and 23a as described above, the light scattering structure 27 and the sphere 46 may be disposed on the rear surface of the light guide plates 23 and 23a, for example. Further, the LCD panel unit 18 as described above can be used not only for the cellular phone terminal device 11 but also for other electronic devices such as PDAs (portable information terminals), digital cameras, personal computers, and the like. In addition, the light guide plates 23 and 23a as described above may be incorporated in a so-called back light type LCD panel unit in addition to the front light type.

Claims (14)

An entrance face defined on the end face of the light transmitting plate member; A plurality of rows of prisms formed on a surface of the light transmitting plate member at a position away from the incident surface; A flat region defined on the surface of the light transmitting plate member along an arbitrary straight line between the incident surface and the prism; A light scattering structure disposed between the incidence surface and the prism and formed on the surface of the light transmitting plate member outside the flat region, the light scattering structure having an interface for diffusely reflecting light Light guide plate comprising a. The light guide plate according to claim 1, wherein the light scattering structure comprises abrasive traces. The light guide plate of claim 1, wherein the light scattering structure includes a curved prism extending toward the flat region while being curved. The light guide plate according to claim 1, wherein the light scattering structure includes protrusions protruding from a surface of the light transmitting plate member. The light scattering structure of claim 1, wherein the light scattering structure includes a first protrusion projecting from the surface of the light transmitting plate member, and a second protrusion projecting from the surface of the light transmitting plate member at a position away from the flat region than the first protrusion. The boundary surface of the first projection and the light transmitting plate member is larger than the boundary surface of the second projection and the light transmitting plate member in a direction orthogonal to the arbitrary straight line. The light scattering structure of claim 1, wherein the light scattering structure includes a first protrusion projecting from the surface of the light transmitting plate member, and a second protrusion projecting from the surface of the light transmitting plate member at a position away from the flat region than the first protrusion. And the interface between the first projection and the light transmitting plate member is smaller in the direction orthogonal to the arbitrary straight line than the interface between the second projection and the light transmitting plate member. The light scattering structure of claim 1, wherein the light scattering structure includes a first protrusion projecting from the surface of the light transmitting plate member, and a second protrusion projecting from the surface of the light transmitting plate member at a position away from the flat region than the first protrusion. The interface surface area of the first projection and the light transmitting plate member is defined to be larger than the interface surface area of the second projection and the light transmitting plate member. The light scattering structure of claim 1, wherein the light scattering structure includes a first protrusion projecting from the surface of the light transmitting plate member, and a second protrusion projecting from the surface of the light transmitting plate member at a position away from the flat region than the first protrusion. The interface surface area of the first projection and the light transmitting plate member is smaller than the interface surface area of the second projection and the light transmitting plate member. The light scattering structure of claim 1, wherein the light scattering structure includes a first protrusion projecting from the surface of the light transmitting plate member, and a second protrusion projecting from the surface of the light transmitting plate member at a position away from the flat region than the first protrusion. In addition, the interface shape of the first and second protrusions and the light transmitting plate member is defined in common, and the first and second protrusions define a unique reference line with the interface shape that crosses the boundary surface. A light guide plate, characterized in that the intersection angle between the reference line and the arbitrary straight line is larger than the intersection angle between the reference line of the second projection and the arbitrary straight line. The first projection group consisting of a plurality of projections projecting from the surface of the light transmitting plate member, and projecting from the surface of the light transmitting plate member at a position farther from the flat region than the first projection group. And a second projection group composed of a plurality of projections, wherein the projections of the first projection group are arranged to be denser than the projections of the second projection group. A plurality of rows of prisms formed on the surface of the light transmissive plate member at a position away from the incidence plane, the light transmissive plate member along an arbitrary straight line between the incident surface and the prism A light guide plate comprising a flat region defined on a surface, and a plurality of spheres arranged on the surface of the light transmitting plate member outside the flat region between the incident surface and the prism and causing light scattering. Light source; A light guide member for reflecting light emitted from the light source and outputting the light from an emission surface; A light transmitting plate member facing the light guide member; An incidence surface defined on an end face of the light transmitting plate member and opposed to an exit surface of the light guide member; A plurality of prisms formed on a surface of the light transmitting plate member at a position away from the incidence surface to reflect light emitted from the light guide member; A flat region defined on the surface of the light transmitting plate member along an arbitrary straight line between the incident surface and the prism; The light scattering structure is disposed between the incident surface and the prism and formed on the surface of the light transmitting plate member at the outside of the flat region, and has a boundary surface which diffusely reflects light. Light source unit comprising a. A light source; A light guide member for reflecting light emitted from the light source and outputting the light from an emission surface; A light transmitting plate member facing the light guide member; An incidence surface defined on a cross section of the light transmitting plate member and opposed to an exit surface of the light guide member; A plurality of prisms formed on a surface of the light transmitting plate member at a position away from the incidence surface to reflect light emitted from the light guide member; A flat region defined on the surface of the light transmitting plate member along an arbitrary straight line between the incident surface and the prism; A light scattering structure disposed between the incidence surface and the prism and formed on a surface of the light transmitting plate member at an outer side of the flat region, the light scattering structure having an interface for diffusely reflecting light; Display panel facing the surface of the light transmitting plate member Display panel unit comprising a. housing; A light source embedded in the housing; A light guide member for reflecting light emitted from the light source and outputting the light from an emission surface; A light transmitting plate member facing the light guide member; An incidence surface defined on a cross section of the light transmitting plate member and opposed to an exit surface of the light guide member; A plurality of prisms formed on a surface of the light transmitting plate member at a position away from the incidence surface to reflect light emitted from the light guide member; A flat region defined on the surface of the light transmitting plate member along an arbitrary straight line between the incident surface and the prism; A light scattering structure disposed between the incidence surface and the prism and formed on a surface of the light transmitting plate member at an outer side of the flat region, the light scattering structure having an interface for diffusely reflecting light; A display panel facing the surface of the light transmissive plate member and facing the window opening defined by the housing; Electronic device comprising a.

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