JPH11144512A - Illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the whole thickness of a transmission type display device and perform an uniform image display with high luminance by providing a reflector the light reflected by the reflecting surface of which contains a mirror reflection component and a perfect diffused reflection component, and arranging a light source opposite to the reflecting surface. SOLUTION: A transmission type display device 21 has a cylindrical light source 23 and a corrugated sectional reflecting plate 24 arranged in positions separated from the back surface of a transmission type display body 22. Of the reflecting surface 24a of the reflecting plate 24, mirror reflection is performed in the particle non-adhered mirror part which performs perfect diffused reflection, and perfect diffused reflection is performed in the particle adhered part which performs perfect diffused reflection. The curvature of the reflecting plate 24 is regulated to regulate the ratio of the light incident on the transmission type display body 22 of the mirror reflection component, whereby the ratio of mirror reflection component to perfect diffused reflection component incident on the transmission type display body 22 can be regulated to uniform the distribution of illuminance of the transmission type display body 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an irradiation device for irradiating an object to be irradiated with light emitted from a light source.

[0002]

2. Description of the Related Art In a transmissive display device such as a liquid crystal display device,
Light is emitted from the back to a transmissive display such as a liquid crystal panel to display an image on the front. FIG. 4 shows a main part of a transmission type display device having an irradiation device according to a conventional example of the present invention. In this transmissive display device 11, a transmissive light diffusion plate 13 is disposed on the back of a transmissive display body 12, and a cylindrical light source 14 and a cross-sectional The reflection plate 15 is disposed.

As the reflecting plate 15, a reflecting surface 15a on the side of the light source 14 performs a specular reflection or a reflecting surface 15a.
A perfect diffuse reflection plate that performs perfect diffuse reflection is used. 5 and 6 show the illuminance distribution on the light source 14 side surface of the transmissive light diffusion plate 13, and FIG.
FIG. 6 shows a case where a specular reflector is used as 5 and FIG. 6 shows a case where a perfect diffuse reflector is used as a reflector 15.

As is clear from FIG. 5, when a specular reflector is used as the reflector 15, the transmission type light diffuser 13 is used.
Among them, the illuminance of the portion facing the light source 14 is relatively low, and as is clear from FIG. 6, when the perfect diffusion reflection plate is used as the reflection plate 15, the transmission type light diffusion plate 13 The illuminance at the portion facing the boundary between the light sources 14 is relatively low.

That is, in any case, the illuminance on the surface on the light source 14 side of the transmissive light diffusing plate 13 is not uniform, and the brightness of the image displayed on the front surface of the transmissive display 12 is not uniform. It is uniform.

For this reason, the transmission type display device 1 shown in FIG.
1, the light diffusion effect is increased by increasing the concentration of the light diffusion substance in the transmission type light diffusion plate 13 or by laminating the transmission type light diffusion plate 13, and the reflection plate 15 and the transmission type display 1 are provided.
2 so that the light source 14 can be regarded as a linear light source.
Between the light source 14 and the transmission type display 1
Or the distance between the two.

[0007]

However, when the light diffusion effect of the transmission type light diffusion plate 13 is enhanced, the transmission type light diffusion plate
3, the light transmittance of the display 3 decreases, and the luminance of an image displayed on the front surface of the transmission display 12 decreases. Also, the light source 14
Between the light source 14 and the transmission type display 1
When the distance between them is increased, the overall thickness of the transmissive display device 11 increases.

Therefore, when the present invention is applied to a transmissive display device and illuminates the transmissive display body from the back, a high brightness and uniform image can be obtained while reducing the overall thickness of the transmissive display device. It is an object to provide an irradiation device capable of displaying.

[0009]

In the irradiation apparatus according to the first aspect, the light source is disposed so as to face the reflecting surface of the reflector, so that the light emitted from the light source and incident on the reflecting surface of the reflector is not affected. Although the light is reflected by the reflecting surface, the light reflected by the reflecting surface of the reflector includes a specular reflection component and a perfect diffuse reflection component.

For this reason, a light diffusion plate having a high light diffusion effect is arranged between the irradiation object and the irradiation device, or the distance between the light source and the reflector or the distance between the light source and the irradiation object is reduced. Even if it is not increased, the illuminance of the irradiation target can be made uniform only by adjusting the ratio between the specular reflection component and the perfect diffuse reflection component incident on the irradiation target.

In the irradiation apparatus according to the second aspect, since the reflecting surface of the reflector has a mirror surface and particles adhering to the mirror surface and performing perfect diffuse reflection, the curvature of the mirror surface and the adhesion layer of the particles are reduced. By adjusting the thickness, it is possible to easily adjust the ratio between the specular reflection component and the perfect diffuse reflection component incident on the irradiation object.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to an irradiation device of a transmission type display device will be described below with reference to FIGS. FIG. 2 shows a main part of the transmission type display device. In the transmissive display device 21, a cylindrical light source 23 and a reflecting plate 24 having a cross-sectional wave shape are arranged at positions separated from the rear surface of the transmissive display body 22. The reflecting surface 24a of the reflecting plate 24 is formed by adhering particles that perform perfect diffuse reflection, such as magnesium oxide particles generated by burning a magnesium ribbon, to a mirror surface.

For this reason, specular reflection is performed on the mirror surface portion of the reflection surface 24a to which particles that perform perfect diffuse reflection are not attached. Further, at the attachment portion of the particles that perform perfect diffuse reflection, as shown in FIG. 3, even when the irradiation direction 25 of the light emitted from the light source 23 is perpendicular to the reflection surface 24a, the luminous trajectory 26 of the reflection surface is circular. Perfect diffuse reflection is performed according to Lambert's cosine law.

Assuming that the thickness of the adhesion layer of the particles performing perfect diffuse reflection is constant and the ratio of the specular reflection component to the perfect diffuse reflection component of the light reflected by the reflecting surface 24a is constant, the perfect diffuse reflection component Since the luminance is the same in any direction, the curvature of the cross-sectional reflector 24 is adjusted to adjust the ratio of the light incident on the transmissive display 22 out of the specular reflection component, whereby the transmissive type is obtained. The ratio between the specular reflection component and the perfect diffuse reflection component incident on the display 22 can be adjusted.

Further, even if the curvature of the reflecting plate 24 of a cross-sectional wave type is constant and the ratio of the light incident on the transmissive display 22 among the specular reflection components is constant, the adhesion of the particles that perform perfect diffuse reflection is not caused. When the thickness of the layer is increased, the specular reflection component of the light reflected by the reflection surface 24a decreases and the perfect diffuse reflection component increases. Therefore, by adjusting the thickness of the particle adhesion layer, it is possible to adjust the ratio of the specular reflection component and the perfect diffusion reflection component incident on the transmissive display 22.

On the other hand, as shown in FIGS. 1A and 1B, the distribution of the illuminance of the transmissive display 22 due to the specular reflection component and the distribution of the illuminance of the transmissive display 22 due to the perfect diffuse reflection component are in phase. Since they are shifted from each other by a half cycle, as described above, by adjusting the ratio between the specular reflection component and the perfect diffusion reflection component incident on the transmissive display body 22, as shown in FIG. The distribution of the illuminance of the type display 22 can be made uniform.

If the distribution of the illuminance of the transmissive display 22 becomes uniform, the brightness of the image displayed on the transmissive display 22 also becomes uniform. Moreover, the illuminance distribution of the transmissive display 22 becomes uniform only by adjusting the ratio of the specular reflection component and the perfect diffuse reflection component incident on the transmissive display 22, and as shown in FIG. Since no transmissive light diffusion plate is provided between the transmissive display 22 and the light source 23, the brightness of the image displayed on the transmissive display 22 is high.

Further, only by adjusting the ratio between the specular reflection component and the perfect diffuse reflection component incident on the transmissive display 22,
Since the distribution of illuminance of the transmissive display 22 is uniform, it is not necessary to increase the distance between the light source 23 and the reflector 24 or the distance between the light source 23 and the transmissive display 22. The entire thickness of the display device 21 is thin.

In the above embodiment, the invention of the present application is applied to the irradiation device of the transmission type display device. However, the invention of the present application can be applied to an irradiation device other than the irradiation device of the transmission type display device. it can.

[0020]

In the irradiation apparatus according to the first aspect, a light diffusion plate having a high light diffusion effect is disposed between the object to be irradiated and the irradiation apparatus, the distance between the light source and the reflector, or the light source and the object. Even if the distance between the object and the object is not increased, simply adjusting the ratio of the specular reflection component and the perfect diffuse reflection component incident on the object can make the illumination of the object uniform. Therefore, if the present invention is applied to a transmissive display device and the transmissive display body is irradiated from the back, it is possible to display a high-luminance and uniform image while reducing the overall thickness of the transmissive display device.

In the irradiation apparatus according to the second aspect, by adjusting the curvature of the mirror surface and the thickness of the particle adhesion layer, the ratio of the specular reflection component incident on the object to be irradiated and the perfect diffuse reflection component can be easily adjusted. When applied to a transmissive display device and illuminating the transmissive display body from the back, a high-luminance and uniform image can be displayed at low cost while reducing the overall thickness of the transmissive display device. can do.

[Brief description of the drawings]

FIG. 1 is a graph of an illuminance distribution for explaining the principle of the present invention.

FIG. 2 is a sectional view of a main part of a transmission type display device having an irradiation device according to an embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining perfect diffuse reflection in one embodiment.

4A and 4B show a transmission type display device having an irradiation device according to a conventional example of the present invention, wherein FIG. 4A is a front view, and FIG. 4B is a cross-sectional view taken along a line BB of FIG. It is.

FIG. 5 is a graph of an illuminance distribution in a case where a mirror reflector is used as a reflector in an irradiation apparatus of a conventional example.

FIG. 6 is a graph of an illuminance distribution in a case where a completely diffuse reflection plate is used as a reflection plate in a conventional irradiation apparatus.

[Explanation of symbols]

 23 ... light source, 24 ... reflector (reflector), 24a ... reflecting surface

Claims (2)

[Claims] 1. A light source comprising: a reflector in which light reflected by a reflection surface includes a specular reflection component and a perfect diffuse reflection component; and a light source disposed opposite to the reflection surface. Irradiation device. 2. The irradiation mechanism according to claim 1, wherein the reflection surface has a mirror surface and particles that adhere to the mirror surface and perform perfect diffuse reflection.