JPH07301800A - Light source device for liquid crystal projector - Google Patents

Abstract

PURPOSE:To enhance the utilization factor of light and to improve the luminance of the peripheral part of a projected picture by guiding light diffused to the outside of an optical path to the peripheral part of the projected picture. CONSTITUTION:The light from a light source 1 is reflected by a reflector 2, condensed by a condesing lens 3, generated as picture light by irradiating a liquid crystal panel 4 driven according to a video signal, and projected to a screen by a projection lens 5. A hollow square pillar-like light guiding body 6 formed of transparent glass or transparent synthetic resin is disposed to surround the optical path of the light from the light source. Then, the light 7 diffused to the outside of the optical path is made incident on the light guiding body 6, guided in the light guiding body 6, projected from a side surface 8 toward the condensing lens, and condensed by the condensing lens to irradiate the liquid crystal panel, thereby contributing to the improvement of the luminance of the peripheral part of the projected picture.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device for a liquid crystal projector, and more particularly to a device for improving the brightness of the peripheral portion of a projected image.

[0002]

2. Description of the Related Art In a projector using a liquid crystal panel, a metal halide lamp or the like is used as a light source 1 in order to increase the utilization rate of light from a light source, as in the configuration example of a color separation optical system shown in FIG. Behind the light source 1 is a reflector 2
A liquid crystal panel 4 driven by a video signal by arranging the
And the image light generated by the liquid crystal panel 4 is projected by a projection lens 5 onto a screen (not shown). However, the light amount distribution of the light flux is highest in the central portion, and the light amount gradually decreases as the distance from the central portion increases, so that the image on the screen has lower brightness in the peripheral portion than in the central portion. Moreover, as the light source light, even if the reflector 2 or the like is used as described above, there is the light 21 diffused to the periphery without irradiating the liquid crystal panel 4, and the light source light is not sufficiently utilized.
Increasing the reflector 2 will improve the light utilization rate,
The device becomes large.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention guides the light diffused to the periphery by the color separation optical system to irradiate the liquid crystal panel without irradiating the liquid crystal panel, and the light source light is used. It is an object of the present invention to provide a device that enhances the utilization rate of light and improves the brightness of the peripheral portion of the projected image.

[0004]

In order to solve the above-mentioned problems, the present invention reflects light from a light source by a reflector, condenses the light with a condenser lens and irradiates the liquid crystal panel with image light generated by the liquid crystal panel. A projection lens is used to project on a screen, a hollow prismatic light guide surrounding the light path between the light source and the condenser lens is provided, and light diffused outside the light path is made incident on the light guide and Provided is a light source device of a liquid crystal projector in which guided light is emitted from one side surface of a light guide toward a condenser lens.

[0005]

With the above construction, in the light source device of the liquid crystal projector according to the present invention, the light beam diffused to the outside of the optical path from the light source to the condenser lens is incident on the hollow prismatic light guide surrounding the optical path. Then, the light is guided in the light guide and emitted from the surface on the side of the condensing lens, or is reflected in the direction of the condensing lens by the hollow prismatic mirror surrounding the optical path and is condensed by the condensing lens. Irradiate.

[0006]

Embodiments of the light source device of a liquid crystal projector according to the present invention will be described in detail below with reference to the drawings. 1 is a partial configuration diagram of an embodiment of a light source device for a liquid crystal projector according to the present invention, FIG. 2 is a partially enlarged view, and FIG. 3 is a configuration diagram of an essential part for another embodiment of a light source device for a liquid crystal projector according to the present invention. is there.

In FIG. 1, reference numeral 1 denotes a light source, which emits white light by, for example, a metal halide lamp. A reflector 2 reflects the light of the light source 1 forward. A condenser lens 3 condenses the light from the light source 1 and the reflector 2. Four
Is a liquid crystal panel, which is driven by a video signal and appropriately transmits or blocks light from the condenser lens 3. A projection lens 5 projects the image light generated by the liquid crystal panel 4 onto a screen (not shown). Reference numeral 6 is an optical derivative, which is made of a member having a high refractive index such as transparent glass or transparent synthetic resin,
It is formed into a rectangular hollow prismatic shape corresponding to the shape of the liquid crystal panel 4, and is arranged so as to surround the optical path between the light source 1 and the condenser lens 3. Then, as shown in the partially enlarged view of FIG. 2, the side surface 9 on the side of the condenser lens 3 is formed at an appropriate angle.

In FIG. 3, reference numeral 11 denotes a mirror, which is formed in a rectangular hollow prism shape corresponding to the shape of the liquid crystal panel 4, and is arranged in a required range surrounding the optical path between the light source 1 and the condenser lens 3.

Next, the operation of the light source device of the liquid crystal projector according to the present invention will be described. In the case of FIG. 1, the light 7 diffused out of the optical path from the light source 1 or the like that does not illuminate the liquid crystal panel is incident on the light guide 6 formed of a member having a high refractive index such as transparent glass or transparent synthetic resin. The light passes through the light guide 6 with almost no attenuation as indicated by the arrow 9 in FIG. 2 and exits from the side surface 8 on the side of the condenser lens 3, is condensed by the condenser lens 3, and illuminates the liquid crystal panel 4. The angle of the side surface 8 of the light guide 6 with respect to the optical axis is appropriately set so that the light passing through the light guide 6 and emitted from the side surface 8 is distributed to the peripheral portion of the projected image.

In the case of FIG. 3, the light diffused from the light source 1 or the like to the outside of the optical path 12 is reflected by the mirror 11 formed in a rectangular hollow prismatic shape corresponding to the shape of the liquid crystal panel 4, and the light source 1 or the like is used. Together with the direct light, the light is condensed by the condenser lens 3 to illuminate the liquid crystal panel 4, and the image light generated by the liquid crystal panel 4 is projected on the screen by the projection lens 5. Mirror 11
Is set to an appropriate position near the condenser lens 3 with an appropriate width, and the light source light reflected by the mirror 11 enters the effective diameter of the projection lens 5 through the condenser lens 3 and the liquid crystal panel 4. Are arranged so as to be distributed in the peripheral portion of the projected image within a certain range, and at the same time, unnecessary light that does not enter the projection lens 5 is not reflected.

[0011]

As described above, according to the light source device of the projector according to the present invention, the light guide or mirror formed in the rectangular hollow prism shape corresponding to the shape of the liquid crystal panel is used for the optical path of the light source. Is arranged so as to surround the light source and guides or reflects the light diffused outside the optical path that is not effectively used as the projection image light so as to be distributed in the peripheral portion of the projection image, and effectively uses the invalid light, Moreover, since this light is guided to the peripheral portion of the projected image, it is possible to enhance the brightness of the peripheral portion, which is lower than the central portion.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment of a light source device of a liquid crystal projector according to the present invention.

FIG. 2 is a partial configuration diagram of an embodiment of a light source device of a liquid crystal projector according to the present invention.

FIG. 3 is a main part configuration diagram of another embodiment of the light source device of the liquid crystal projector according to the present invention.

FIG. 4 is an example of a light source device of a conventional liquid crystal projector.

[Explanation of symbols]

 1 light source (metal halide lamp) 2 reflector 3 condenser lens 4 liquid crystal panel 5 projection lens 6 light guide (hollow prism) 8 side surface of light guide 11 mirror (hollow prism)

Claims (7)

[Claims] 1. A light source and a collector in which light from a light source is reflected by a reflector, condensed by a condenser lens to illuminate a liquid crystal panel, and image light generated by the liquid crystal panel is projected on a screen by a projection lens. A hollow prismatic light guide that surrounds the optical path between the light lenses is provided, and the light diffused outside the light path is incident on the light guide, and the light guided inside the light guide is directed from one side of the light guide toward the condenser lens. A light source device for a liquid crystal projector that emits light to the inside. 2. The light source device of a liquid crystal projector according to claim 1, wherein the shape of the side surface of the light guide is a rectangle corresponding to the shape of the liquid crystal panel. 3. The light source device for a liquid crystal projector according to claim 1, wherein the light guide is formed of transparent glass. 4. The light source device for a liquid crystal projector according to claim 1, wherein the light guide is formed of a transparent synthetic resin. 5. A light source and a collector in which light from a light source is reflected by a reflector, condensed by a condenser lens to illuminate a liquid crystal panel, and image light generated by the liquid crystal panel is projected on a screen by a projection lens. A light source device for a liquid crystal projector, comprising a hollow prismatic mirror surrounding an optical path between optical lenses and configured to reflect light diffused outside the optical path toward a condenser lens. 6. The light source device of a liquid crystal projector according to claim 5, wherein the shape of the side surface of the mirror is a rectangle corresponding to the shape of the liquid crystal panel. 7. The mirror is arranged in a range in which light reflected by the mirror enters the effective diameter of the projection lens through the condenser lens and the liquid crystal panel. A light source device for the liquid crystal projector described.