JP2003330393A - Display device and image communication machine having the same, and copying machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the illuminance distribution of a display surface of a display plate having translucency uniform by using a light source emitting converging light. <P>SOLUTION: The display device (1) is equipped with the display plate (2) having translucency, a light source (3) disposed alongside the display plate, a reflection plate (4) disposed between the display plate and the light source in order to reflect the light emitted by the light source to the rear surface of the display plate, a first diffusion sheet (6) disposed between the display plate and the reflection plate in order to diffuse the light reflected by the reflection plate to the rear surface of the display plate, and a second diffusion sheet (5) disposed between the reflection plate and the light source in order to diffuse the light emitted by the light source to the reflection plate. As a result, the spot light emitted from the light source is diffused by the diffusion effect of the second diffusion sheet, is thereafter reflected by the reflection plate, is transmitted as the reflected and diffused light through the first diffusion sheet, and is further diffused by the diffusion effect of the first diffusion sheet, by which the rear surface of the display plate is illuminated with this light. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, an image communication device including the display device, and a copying machine.

[0002]

2. Description of the Related Art Conventionally, as a display device of an image communication device or a copying machine, a backlight transmissive liquid crystal panel which is illuminated from the back surface thereof is generally used. In the liquid crystal display device 20 using this backlight, for example, as shown in FIG. 11, a light source (for example, an LED) 22 that irradiates light from the side of the liquid crystal panel 21, and the light emitted by the light source 22 is emitted from the liquid crystal panel 21. Reflector 23 for reflecting to the back, and reflector 23
And a light diffusion sheet 24 arranged between the liquid crystal panel 21 and the back surface of the liquid crystal panel 21. In this conventional liquid crystal display device 20, the light reflected by the reflection plate 23 is used as the diffusion sheet 24.
The illuminance distribution on the display surface of the liquid crystal panel 21 is made uniform by diffusing the light and irradiating the back surface of the liquid crystal panel 21. Further, a diffusion sheet 24 is provided on the back surface of the liquid crystal panel 21.
By disposing, the illumination device such as the light source 22 provided on the back side of the liquid crystal panel 21 is prevented from being seen through the surface of the liquid crystal panel 21. The reason why the light from the side of the liquid crystal panel 21 is reflected and applied to the back surface of the liquid crystal panel 21 is to secure a sufficient optical path length and to make the display device 20 thin.

[0003]

However, according to the above-mentioned prior art, when an LED is used as a light source, LE is used.
The light emitted by D has a converging property, and after being reflected by the reflection plate, it is incident on the diffusion sheet as spot light. However, since the diffusion angle of a general diffusion sheet is not so wide, diffusion there is insufficient. Tended to be. Therefore, the illuminance distribution on the display surface of the liquid crystal panel is not completely uniform, and the position corresponding to the center of the light source is bright, but the peripheral is dark.

The present invention has been made to solve the above-mentioned disadvantages of the prior art, and its main purpose is to transmit light even if a relatively inexpensive LED that emits convergent light is adopted as a light source. It is an object of the present invention to provide a display device capable of uniformizing the illuminance distribution on the display surface of a display plate having the above, an image communication device including the same, and a copying machine.

[0005]

In order to achieve such an object, the first aspect of the present invention provides a light-transmitting display plate (2) and a light source (3 provided on the side of the display plate. ), And a reflector (4) provided between the display plate and the light source to reflect the light emitted from the light source to the back face of the display plate, and a display for diffusing the light reflected by the reflector plate to the back face of the display plate. A first diffusion sheet (6) provided between the plate and the reflection plate, and a second diffusion sheet (5) provided between the reflection plate and the light source to diffuse the light emitted from the light source to the reflection plate. ) And a display device characterized by being provided.

With this configuration, the spot light emitted from the light source is diffused toward the reflecting plate by the diffusing action of the second diffusing sheet and then is reflected by the reflecting plate to be the first diffusing light as reflected diffused light. Reach the seat. The reflected diffused light from the reflecting plate is further diffused by the diffusing action of the first diffusing sheet and illuminated on the back surface of the display plate. Therefore, even if a light source that emits convergent light is adopted, the illuminance distribution on the illuminated surface of the display plate can be made uniform.

In the second aspect, the first diffusion sheet and the second diffusion sheet are integrally formed in a substantially L shape. With this configuration, the first diffusion sheet side is the upper surface and the second diffusion sheet side is the side surface, and the reflection surface of the reflection plate is covered with the diffusion sheet so that the first diffusion sheet side is predetermined. If the second diffusion sheet is attached at position 2, the second diffusion sheet side is also attached at a predetermined position at the same time, so that the number of steps for attaching the two diffusion sheets can be reduced. Moreover, if the display plate is fixed to the upper surface of the first diffusion sheet side, the second diffusion sheet side is also fixed, so that no special fixing means on the second diffusion sheet side is required. .

In the third aspect of the present invention, a bent portion (9) is formed at the edge of the first diffusion sheet side, which is integrally formed in the above-mentioned L-shape, on the side opposite to the connection portion with the second diffusion sheet. To be formed. With this configuration, when the first diffusion sheet side is the upper surface and the second diffusion sheet side is the side surface and the reflection sheet of the reflection plate is covered with the diffusion sheet, the play of the first diffusion sheet side is reduced. The position on the first diffusion sheet side can be easily determined by hooking the bent portion formed on the edge to the upper end of the reflection plate. Therefore, the first diffusion sheet side is set on the reflection plate by the weight of the second diffusion sheet side. It can be prevented from slipping off from the upper end of the. Moreover, the rigidity of the first diffusion sheet side is increased by the bent portion, and the deformation of the first diffusion sheet facing the back surface of the display plate is suppressed, so that the reflected diffused light from the reflection plate is reflected on the back surface of the display plate. It can be surely diffused toward.

According to a fourth aspect of the present invention, the second diffusion sheet is integrally formed in the above-mentioned L shape, and the second diffusion sheet is connected to the first diffusion sheet. To
It is provided on the edge of the reflector near the light source. With this configuration, when the first diffusion sheet side is the upper surface and the second diffusion sheet side is the side surface and the reflection sheet of the reflection plate is covered with the diffusion sheet, the play of the second diffusion sheet side is reduced. The position on the second diffusion sheet side can be easily determined only by engaging the edge with the engaging portion of the reflection plate. In addition, since the free edge on the second diffusion sheet side is engaged with the one edge of the reflector, the deformation of the free edge on the second diffusion sheet side is suppressed, so that the converged light emitted from the light source is converged. Can be surely diffused toward the reflector.

Further, in the fifth aspect, the light shielding walls (11) are provided at both ends of the reflection plate. By doing so, it is possible to prevent the diffused light from the diffuser sheet from leaking out from both ends of the reflector, so that the diffused light can be surely applied to the back surface of the liquid crystal display plate. Moreover, when the diffusion sheet integrally formed in an L shape is covered with the reflection surface of the reflection plate with the first diffusion sheet side as the upper surface and the second diffusion sheet side as the side surface, both sides of the reflection plate are covered. Since the diffusion sheet can be sandwiched between the light shielding walls at the ends, a special fixing member is not required for fixing the diffusion sheet.

In the sixth aspect, the reflecting surface (13) of the reflecting plate is concave. By doing so, the diffused light from the second diffusing sheet reaches the light receiving surface of the first diffusing sheet without being excessively scattered when it is reflected by the reflecting plate, so that the conventional planar reflection Compared to the one using a plate, the second dimension is achieved without increasing the thickness of the display device.
The diffused light from the diffusing sheet can be irradiated onto the light receiving surface of the first diffusing sheet without waste.

Further, in claim 7, the reflecting surface (14) of the reflecting plate is roughened. By doing so, the diffusion range of the reflected light by the reflection plate can be further expanded, so that the illuminance distribution of the display plate can be made more uniform when a light source that emits convergent light is adopted.

In the eighth aspect, the creases are formed on the diffusion surface (15) of the diffusion sheet. By doing so, the diffusion action of the illumination light of the diffusion sheet can be further enhanced, so that the uniformity of the illuminance distribution of the display plate can be promoted when a point light source that emits convergent light is adopted.

Further, in claim 9, the diffusion sheet is formed of a polyester sheet. By doing so, the good diffusion characteristics of the polyester sheet can contribute to uniforming the illuminance distribution of the display plate when a light source that emits convergent light is adopted.

By applying the above display device to an image communication device (claims 10 to 18), the usability of the image communication device can be further enhanced, and by applying it to a copying machine (claim 19). 27), the usability of the copying machine can be further improved.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The configuration of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a conceptual diagram showing the basic structure of a display device according to the present invention. The display device 1 includes a display plate 2 having a light-transmitting property, such as a liquid crystal panel, and a display plate 2.
Between the display plate 2 and the light source 3 and a light source 3 which is provided on the side of (i.e., a surface orthogonal to the display surface of the display plate) and includes, for example, a plurality of (for example, three) LEDs that emit convergent light To bend the optical axis at a right angle, the reflector 4 is installed so as to be inclined at an included angle of 45 degrees with the display surface of the display plate 2, and the reflector 4 is formed by diffusing light emitted from the light source 3. The front stage (second) diffusion sheet 5 formed of, for example, a polyester sheet having relatively good diffusion characteristics, which is provided immediately before the reflection plate 4 to diffuse the light reflected by the reflection plate 4. The rear (first) diffusion sheet 6 is formed immediately after the reflection plate 4 so as to be applied to the back surface of the display plate 2 and is formed of, for example, a polyester sheet having relatively good diffusion characteristics.

The light source 3 is the light source 3 in the reflection plate 4.
It is attached to a support plate 8 connected to the terminal end of the horizontal portion 7 extending from one end on the side closer to.

In the display device 1 thus constructed, the illumination light emitted from the light source 3 made of an LED has a straight traveling property and a converging property, but when passing through the front diffusion sheet 5, After being diffused by the diffusing action of the front diffusion sheet 5, it is reflected by the reflecting plate 4. Then, the reflected diffused light is further diffused by the diffusing action of the post-diffusion sheet 6 when passing through the post-diffusion sheet 6, and applied to the back surface of the display plate 2. In this way, the illuminance distribution on the illuminated surface of the display plate 2 can be made uniform even with a highly convergent point light source.
A relatively inexpensive LED can be adopted as the light source.

As shown in FIGS. 2 to 4, the front diffusion sheet 5 and the rear diffusion sheet 6 are integrally formed by bending one sheet into a substantially L shape, and the rear diffusion sheet 6 is formed.
On the edge of the opposite side to the connection part with the front diffusion sheet 5 on the side,
A bent portion 9 is formed toward the opposite side of the surface facing the display plate 2.

On the other hand, at the edge of the reflection plate 4 on the side closer to the light source 3, there is formed an engaging portion formed of a groove which can be engaged with an edge on the opposite side of the connecting portion with the rear diffusion sheet 6 of the front diffusion sheet 5. 10
Are formed. Further, as shown in FIG.
As also shown, a light-shielding wall 11 having a right-angled triangle with the reflecting surface of the reflecting plate 4 as the hypotenuse is provided.

In assembling the display device 1 having such a structure, first, the diffusion sheet assembly 12 bent and formed in a substantially L-shape is arranged so that the rear diffusion sheet 6 side is the upper surface.
Moreover, the front diffusion sheet 5 side is made to be a side surface and the reflection surface of the reflection plate 4 is covered. At this time, both side edges of the diffusion sheet assembly 12 are sandwiched between the light-shielding walls 11 formed in the right and left triangles of the reflection plate 4 in the shape of a right triangle, and the bent portion 9 of the free edge on the rear diffusion sheet 6 side is formed. Is hooked on the edge 4a of the reflector 4 on the side closer to the display plate 2, and the free edge 5b on the front diffusion sheet 5 side is attached to the engaging portion 10 formed on the edge of the reflector 4 on the side closer to the light source 3. Engage. And the rear diffusion sheet 6
It is completed by fixing the display board 2 on the upper surface of the.

As described above, according to the configuration of the present invention, if either one of the rear diffusion sheet 6 and the front diffusion sheet 5 is attached at a predetermined position, the other side is simultaneously attached at a predetermined position. Will be done. Moreover, if the display plate 2 is fixed to the upper surface of the rear diffusion sheet 6, the front diffusion sheet 5 is also fixed. In this way
Since the front and rear diffusion sheets 5 and 6 can be easily positioned, the man-hours for attaching the two diffusion sheets can be reduced.

In addition to this, since the rigidity of the rear diffusion sheet 6 side is increased by providing the bent portion 9, the deformation of the rear diffusion sheet 6 facing the back surface of the display plate 2 is suppressed, and the display from the reflection plate 4 is suppressed. It is possible to ensure the diffusivity of the reflected light toward the back surface of the plate 2.

Further, by engaging the free edge on the front diffusion sheet 5 side with one edge of the reflection plate 4, deformation of the free edge on the front diffusion sheet 5 side is suppressed, so that the light is emitted from the light source 3. The illuminated light can be reliably diffused toward the reflector 4.

Further, since the light shielding wall 11 can prevent the diffused light from both the front and rear diffusion sheets 5 and 6 from being scattered from the both sides of the reflection plate 4 to the outside of the display device, It is possible to irradiate the reflected and diffused light toward the rear surface of the display plate 2 without waste.

A structure in which the bent portion 9 is formed on the free end edge on the side of the rear diffusion sheet 6 and an engaging portion 10 with the free edge on the side of the front diffusion sheet 5 are provided at one edge of the reflection plate 4. Even if only one of these is carried out, the position of the other diffusion sheet can be automatically determined by positioning only one diffusion sheet side, and the effect of reducing the mounting man-hour and the rigidity can be obtained. Although the effect of enhancement can be obtained, the effect can be further enhanced if both are carried out at the same time.

The material of the diffusion sheet is not limited to the above polyester, as long as it is a material such as a paper-like or cloth-like sheet made of transparent or translucent fibers, which irregularly diffuses light on the surface or inside. It can be applied as appropriate.

FIG. 6 shows a modified embodiment of the present invention. In the present embodiment, the reflecting surface 13 of the reflecting plate 4 is a concave surface, so that when the diffused light that has passed through the front diffusion sheet 5 is reflected by the reflecting surface 13, it does not diffuse more than necessary, and Light can reach a desired portion on the light receiving surface of the diffusion sheet 6. Therefore, as compared with the one using the above-mentioned flat reflection plate, it is possible to irradiate the illumination light only on the display surface of the display plate 2 with high efficiency without inviting an increase in the size of the display device 1.

FIG. 7 shows another modified embodiment of the present invention. In this embodiment, the reflecting surface 14 of the reflecting plate 4 is a rough surface. As a result, the diffusion range of the illumination light by the reflection plate 4 can be further expanded, so that the uniformity of the illuminance distribution of the display plate 2 when the point light source is adopted can be further promoted.

FIG. 8 shows another modification of the present invention. In this embodiment, creases are formed on the diffusion surface 15 of the diffusion sheet. This makes it possible to further enhance the diffusion action of the illumination light of the diffusion sheet.
It is possible to further promote the uniformization of the illuminance distribution of the display plate 2 when the point light source is adopted.

As shown in FIG. 9, the display device 1 described above has a display 1 of an image communication device (facsimile) 16.
7, the usability of the image communication device 16 can be further enhanced, and as shown in FIG. 10, the usability of the copying machine 18 can be improved by applying it to the display 19 of the copying machine 18. It can be further enhanced.

[0033]

As described in detail above, according to the structure of claim 1 of the present invention, the first diffusion sheet is provided between the display plate and the reflection plate, and the first diffusion sheet is provided between the reflection plate and the light source. Since the second diffusing sheet is provided, the illumination light emitted from the light source is diffused by the diffusing action of the second diffusing sheet and then reflected by the reflecting plate, and the reflected diffused light from the reflecting plate is The diffusing action of the diffusing sheet 1 further diffuses the light and illuminates the back surface of the display plate. This allows
It is possible to obtain a great effect in making the illuminance distribution on the illuminated surface of the display plate even more uniform when the point light source is adopted.

Further, according to the second aspect of the present invention, since the first diffusion sheet and the second diffusion sheet are integrally formed in a substantially L-shape, the first diffusion sheet side is provided. When the first diffusion sheet is attached at a predetermined position when the first diffusion sheet is placed on the upper surface and the second diffusion sheet side is placed on the side surface so as to cover the reflection surface of the reflection plate, at the same time, the second diffusion sheet is also provided at the predetermined position. Since it is mounted at the position, the number of man-hours for mounting the two diffusion sheets can be reduced.

Further, according to the third aspect of the present invention, since the bent portion is formed at the free end edge of the first diffusion sheet side which is integrally formed in a substantially L shape, the bent portion is formed. The position on the side of the second diffusion sheet is also determined only by hooking the upper side edge of the reflection plate, and the weight of the second diffusion sheet side prevents the first diffusion sheet side from slipping off from the upper side edge of the reflection plate. be able to. Moreover, since the rigidity of the first diffusion sheet side is increased by the bent portion, the deformation of the first diffusion sheet facing the back surface of the display plate is suppressed, and the reflected diffused light from the reflection plate is directed to the back surface of the display plate. Can be surely diffused.

According to the structure of claim 4 of the present invention, an engaging portion which is integrally formed in a substantially L shape with the free end edge on the second diffusion sheet side is provided at one end edge of the reflection plate. Therefore, the position on the second diffusion sheet side can be easily determined only by engaging the free end edge on the second diffusion sheet side with the engaging portion of the reflection plate, and further, the position on the second diffusion sheet side can be determined. Since the deformation of the free edge can be suppressed, the illumination light emitted from the light source can be reliably diffused toward the reflector.

Further, according to the fifth aspect of the present invention, since the light shielding walls are provided at both ends of the reflecting plate, it is possible to prevent diffused light from the diffusing sheet from scattering to the outside of the reflecting plate. This makes it possible to improve the irradiation efficiency of the illumination light toward the back surface of the display plate when the point light source is adopted. Moreover, when the diffusion sheet integrally formed in the L shape is covered with the reflection surface of the reflection plate with the first diffusion sheet side as the upper surface and the second diffusion sheet side as the side surface, Since the diffusion sheet can be sandwiched by, it is not necessary to use a special fixing member for fixing the diffusion sheet.

According to the structure of claim 6 of the present invention, since the reflecting surface of the reflecting plate is a concave surface, when the diffused light from the second diffusing sheet is reflected by the reflecting plate, it is scattered more than necessary. The light can reach the light-receiving surface of the first diffusion sheet without having to do so, and the diffused light from the second diffusion sheet can be transmitted without increasing the size of the display device as compared with the one using the flat reflector. The light receiving surface of the first diffusion sheet can be irradiated without waste.

According to the seventh aspect of the present invention, since the reflecting surface of the reflecting plate is a rough surface, the diffusion range of the illumination light by the reflecting plate can be further expanded.
It is possible to further enhance the uniformity of the illuminance distribution of the display plate when the point light source is adopted.

According to the eighth aspect of the present invention, since the wrinkles are formed on the diffusion surface of the diffusion sheet,
The diffusing action of the illumination light of the diffusing sheet can be further enhanced, and the illuminance distribution of the display plate when the point light source is adopted can be made more uniform.

According to the ninth aspect of the present invention, since the diffusion sheet is formed of the polyester sheet, the illuminance distribution of the display plate when the point light source is adopted due to the good diffusion characteristics of the polyester sheet. Can be made more uniform.

By applying the above display device to an image communication device (claims 10 to 18), the usability of the image communication device can be further enhanced, and by applying it to a copying machine (claim 19). 27), the usability of the copying machine can be further improved.

[Brief description of drawings]

FIG. 1 is a conceptual side view showing a basic configuration of a device of the present invention.

FIG. 2 is an exploded perspective view showing components of the device of the present invention.

FIG. 3 is a perspective view showing an assembled state of the device of the present invention.

FIG. 4 is a conceptual side view showing a partial vertical sectional view of the device of the present invention.

FIG. 5 is a conceptual plan view showing a partial horizontal sectional view of the device of the present invention.

FIG. 6 is a conceptual side view showing a modified embodiment of the device of the present invention.

FIG. 7 is a conceptual side view showing another modified embodiment of the device of the present invention.

FIG. 8 is a conceptual side view showing still another modified embodiment of the device of the present invention.

FIG. 9 is an external perspective view of an image communication device to which the device of the present invention is applied.

FIG. 10 is a partial external perspective view of a copying machine to which the device of the present invention is applied.

FIG. 11 is a conceptual side view showing the configuration of a conventional device.

[Explanation of symbols]

1 Display device 2 display board 3 light sources 4 reflector 5 First stage (second) diffusion sheet 6 Second stage (first) diffusion sheet 7 Horizontal part 8 Support plate 9 bending part 10 Engagement part 11 Shading wall 12 Diffusion sheet assembly 13 Reflective surface 14 Reflective surface 15 Diffusion surface 16 image communication equipment 17 displays 18 Copier 19 displays

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 21/00 386 G03G 21/00 386 F term (reference) 2H027 GA03 GA23 GA28 GA29 2H042 BA03 BA20 DA11 DD05 DE04 2H091 FA17Z FA32Z FA34Z FA45Z FD12 FD13 LA09 LA12 LA18 MA10 5C096 AA05 AA27 BA01 CA17 CC06 CE02 CE17 CF07 CF08 CJ01 DA02 EB08 FA12 FA17

Claims (27)

[Claims] 1. A light-transmitting display plate, a light source provided on a side of the display plate, and a display plate and the light source for reflecting light emitted from the light source to a back surface of the display plate. A reflector provided between the first and second reflectors provided between the display plate and the reflection plate to diffuse the light reflected by the reflection plate to the back surface of the display plate.
And a second diffusing sheet provided between the reflection plate and the light source to diffuse the light emitted from the light source to the reflection plate. 2. The display device according to claim 1, wherein the first diffusion sheet and the second diffusion sheet are integrally formed into a substantially L shape. 3. The display device according to claim 2, wherein a bent portion is formed at an edge of the first diffusion sheet side opposite to a connection portion with the second diffusion sheet. . 4. An engaging portion for connecting a connecting portion with the first diffusion sheet on the side of the second diffusion sheet and an edge on the opposite side of the second diffusion sheet is provided at an edge of the reflection plate near the light source. The display device according to claim 2, wherein the display device is a display device. 5. The display device according to claim 1, wherein light-shielding walls are provided at both ends of the reflection plate. 6. The display device according to claim 1, wherein the reflecting surface of the reflecting plate is a concave surface. 7. The display device according to claim 1, wherein the reflecting surface of the reflecting plate is a rough surface. 8. The display device according to claim 1, wherein wrinkles are formed on the diffusion surface of the diffusion sheet. 9. The display device according to claim 1, wherein the diffusion sheet is a polyester sheet. 10. A display plate having translucency, a light source provided on the side of the display plate, and a display plate and the light source for reflecting light emitted from the light source to a back surface of the display plate. A reflector provided between the first and second reflectors provided between the display plate and the reflection plate to diffuse the light reflected by the reflection plate to the back surface of the display plate.
And a second diffusion sheet provided between the reflection plate and the light source to diffuse the light emitted from the light source to the reflection plate. Communication equipment. 11. The image communication device according to claim 10, wherein the first diffusion sheet and the second diffusion sheet are integrally formed into a substantially L shape. 12. The image communication according to claim 11, wherein a bent portion is formed on an edge of the first diffusion sheet side opposite to a connection portion with the second diffusion sheet. Machine. 13. An engaging portion between the connecting portion of the reflecting plate and the first diffusing sheet on the side of the second diffusing sheet and the opposite edge of the reflecting plate is provided on the edge of the reflecting plate close to the light source. The image communication device according to claim 11 or 12, characterized in that. 14. The image communication device according to claim 10, wherein light-shielding walls are provided at both ends of the reflection plate. 15. The image communication device according to claim 10, wherein the reflecting surface of the reflecting plate is a concave surface. 16. The image communication device according to claim 10, wherein the reflecting surface of the reflecting plate is a rough surface. 17. The image communication device according to claim 10, wherein wrinkles are formed on the diffusion surface of the diffusion sheet. 18. The image communication device according to claim 10, wherein the diffusion sheet is a polyester sheet. 19. A light-transmitting display plate, a light source provided on a side of the display plate, and the display plate and the light source for reflecting light emitted from the light source to a back surface of the display plate. A reflector provided between the first and second reflectors provided between the display plate and the reflection plate to diffuse the light reflected by the reflection plate to the back surface of the display plate.
And a second diffusion sheet provided between the reflection plate and the light source to diffuse the light emitted from the light source to the reflection plate. Machine. 20. The copying machine according to claim 19, wherein the first diffusion sheet and the second diffusion sheet are integrally formed in a substantially L shape. 21. The copying machine according to claim 20, wherein a bent portion is formed at an edge of the first diffusion sheet side opposite to a connection portion with the second diffusion sheet. . 22. An engaging portion is provided at an edge of the reflector nearer to the light source, a connecting portion of the second diffusing sheet side with the first diffusing sheet and an opposite edge thereof. 22. The copying machine according to claim 20, wherein 23. The copying machine according to claim 19, wherein light-shielding walls are provided at both ends of the reflecting plate. 24. The copying machine according to claim 19, wherein the reflecting surface of the reflecting plate is a concave surface. 25. The copying machine according to claim 19, wherein the reflecting surface of the reflecting plate is a rough surface. 26. The copying machine according to claim 19, wherein creases are formed on the diffusion surface of the diffusion sheet. 27. The copying machine according to claim 19, wherein the diffusion sheet is a polyester sheet.