JPH1020398A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device capable of efficiently using light emitted from a lamp with a simple constitution and using a light source free from uneven luminance. SOLUTION: The light from the light source 1 is directly emitted to a condenser lens 4, and also, the light is emitted to an elliptic reflection mirror 2 and a flat reflection mirror 3. The outgoing light is reflected by the elliptic reflection mirror 2 and the flat reflection mirror 3, finally, the light is emitted to the condenser lens 4 on the same optical path as that of the light directly emitted to the condenser lens 4. Then, all the light is nearly collimated by the condenser lens 4 and an incident Fresnel lens 12, thereafter, the light is made incident on a liquid crystal panel 7. The light from the condenser lens 4 is received by the liquid crystal panel 7, and then, the light is optically modulated by a video signal, then, the optically modulated light is enlarged and projected through a projecting lens 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a projection type display device using a liquid crystal panel as a light valve.

[0002]

2. Description of the Related Art Hitherto, many projection display devices using a liquid crystal panel have been proposed, and a metal halide lamp or the like is used as a light source thereof. This light source has the configuration shown in FIG.

The prior art will be described below with reference to FIG.

In FIG. 3, reference numeral a denotes a light source unit used for an OHP or the like, which comprises a light source 1, a spherical reflecting mirror 2, and a condenser lens 4. B and c are light source units used in a liquid crystal projector or the like. In b, a parabolic reflecting mirror 2 is used, and in c, an elliptical reflecting mirror 2 is used.

The light source 1 has a donut-shaped light emission distribution in a direction perpendicular to the longitudinal direction of the light source, as shown in FIG.

For this reason, in the light source section shown in a, since the reflecting mirror 2 does not sufficiently cover the light source 1, only about 2/3 of the light from the light source can be used. It cannot be said that it is being used effectively. Further, in the light sources b and c, although the light from the light source can be used effectively, the light emission distribution of the light source is as shown in FIG. still,
An integrator lens can be used as a means for suppressing luminance unevenness. However, not only is an integrator lens required separately, but the arrangement of the integrator lens has a disadvantage that the optical path length becomes longer and the device becomes larger.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described drawbacks, and has been made in consideration of the above-described drawbacks. Is provided.

[0008]

According to the present invention, there is provided a light source, a first reflecting mirror formed so as to cover the light source, a second reflecting mirror disposed on an opening surface of the first reflecting mirror, and A condensing lens that receives light from the first and second reflecting mirrors and the light source and converts the light from the light source into substantially parallel light, a transmissive light valve that receives light from the converging lens and light-modulates the light with a video signal; A projection lens for irradiating light modulated by a light valve, wherein the first reflecting mirror is arranged so as to have a first focal point on the light source, and the second reflecting mirror is A projection display device characterized in that a first focal point and a second focal point of one reflecting mirror are arranged so as to coincide with each other.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a projection type display device according to the present invention will be described with reference to the drawings.

FIG. 1 is a view showing a first embodiment of a projection type display apparatus according to the present invention.

FIG. 1A is a top view of the projection display device of the present invention, and FIG. 1B is a side view thereof.

In FIG. 1, light from a light source unit is condensed by a condenser lens 4 so as to irradiate a display area of the liquid crystal panel 7, and is incident on the liquid crystal panel 7 via an incident Fresnel lens 12.

The liquid crystal panel 7 modulates the incident light in accordance with a video signal, and the modulated light is enlarged and displayed on a screen via an emission Fresnel lens 13 and a projection lens 11.

The light source section comprises a light source 1, an elliptical reflector 2 disposed to cover the light source 1, and a planar reflector 3 disposed in an opening 8 of the elliptical reflector 2. The light source unit will be described in detail below.

The light source 1 is a first focal point 5 of the elliptical reflecting mirror 2.
And the planar reflecting mirror 3 is disposed at a position where the first focal point 5 and the second focal point 6 of the elliptical reflecting mirror 2 optically overlap with each other.

The light from the light source 1 directly enters the condenser lens 4 and also enters the elliptical reflecting mirror 2 and the planar reflecting mirror 3.

Light directly incident on the condenser lens 4 from the light source 1 is condensed by the condenser lens 4 so as to irradiate the display area of the liquid crystal panel 7, and is incident on the liquid crystal panel 7 via the incident Fresnel lens 12. Is done. Light incident on the elliptical reflector 2 from the light source 1 is reflected by the elliptical reflector 2 in the direction of the second focal point 6, and is reflected by the planar reflector 3 on the first focal point of the elliptical reflector 2. The light condensed to 5 is emitted to the condensing lens 4, and the condensed light passes through the same optical path as the light directly incident on the condensing lens 4, and is condensed on the liquid crystal panel 7. The light that is again incident on the elliptical reflecting mirror 2 passes through the same optical path, finally enters the condenser lens 4, passes through the same optical path as the light that directly enters the condenser lens 4, and The light is focused on the panel 7.

On the other hand, the light from the light source 1 incident on the planar reflecting mirror 3 is reflected by the planar reflecting mirror 3 and the reflected light is emitted from the second focal point 6 of the elliptical reflecting mirror 2. Most of the light is incident on the elliptical reflecting mirror 2, is condensed at the first focal point 5 by the elliptical reflecting mirror 2, and is emitted toward the condenser lens 4. Then, the light incident on the condenser lens 4 passes through the same optical path as the light directly incident on the condenser lens 4 and is condensed on the liquid crystal panel 7. Further, the light incident on the elliptical reflecting mirror 2 again passes through the same optical path as the light from the light source 1 incident on the elliptical reflecting mirror 2, and
The light is focused on the liquid crystal panel 7.

However, in the above-described first embodiment, a part of the light that has been incident on the planar reflecting mirror 3 from the light source 1 and reflected is not incident on the elliptical reflecting mirror 2, but is reflected on the elliptical reflecting mirror 2.
The light is directly incident on the condenser lens 4 from the opening 8. Such light is not focused on the first focal point 5 of the ellipsoidal reflecting mirror 2, so even if it is incident on the condenser lens 4, it is not incident on the liquid crystal panel 7 or the projection lens, and the light from the light source 1 The problem arises that it is not possible to efficiently use.

Therefore, a second embodiment of the present invention which has solved the above-mentioned disadvantage will be described with reference to FIG.

FIG. 2A is a top view of the projection display device of the present invention, and FIG. 2B is a side view thereof.

The second embodiment differs from the first embodiment in that a spherical reflecting mirror 10 is provided at the center of the planar reflecting mirror 3.

More specifically, in the central portion of the planar reflecting mirror 3, the portion of the planar reflecting mirror 3 within the range connecting the light source 1 and the opening 9 which is a virtual image of the opening 8 is centered on the light source 1. A spherical reflecting mirror 10 is provided. It should be noted that the planar reflecting mirror 3 and the spherical reflecting mirror 10 can be separately arranged.

As described above, by partially forming the spherical reflecting mirror 10, all of the light can be focused on the first focal point 5 of the elliptical reflecting mirror 2.

Next, the flow of light from the light source 1 will be described.

The light from the light source 1 is directly incident on the condensing lens 4 and the elliptical reflector 2 and the planar reflector 3
, And also enters the spherical reflecting mirror 10.

The light directly incident on the condenser lens 4 passes through the condenser lens 4 and is condensed on the liquid crystal panel as in the first embodiment.

The light incident on the elliptical reflecting mirror 2 is transmitted to the elliptical reflecting mirror 2 by the second elliptical reflecting mirror 2 as in the first embodiment.
The light is reflected in the direction of the focal point 6, further condensed by the planar reflecting mirror 3 to the first focal point 5 of the elliptical reflecting mirror 2, and then emitted toward the condenser lens 4. Then, the light incident on the condenser lens 4 passes through the same optical path as the light directly incident on the condenser lens 4, and is condensed on the liquid crystal panel 7. Again, the light incident on the elliptical reflecting mirror 2 passes through the same optical path, and finally condenses on the liquid crystal panel 7 through the same optical path as the light incident on the condenser lens 4.

On the other hand, the light incident on the planar reflecting mirror 3 is
The light is reflected by the planar reflecting mirror 3 and the reflected light is in the same state as the state where the reflected light is emitted from the second focal point 6 of the elliptical reflecting mirror 2. After being focused by the first focal point 5, the light is emitted toward the focusing lens 4. Then, the light incident on the condenser lens 4 passes through the same optical path as the light directly incident on the condenser lens 4 and is condensed on the liquid crystal panel 7. Again, the light incident on the elliptical reflecting mirror 2 is the light from the light source 1
The light is condensed on the liquid crystal panel 7 through the same optical path as the light incident on the liquid crystal panel 7.

Here, the light incident on the spherical reflecting mirror 10 disposed on the planar reflecting mirror 3 is reflected by the spherical reflecting mirror 10, and the reflected light is again reflected on the light source 1 (elliptical reflecting mirror). 2
After being focused on the first focal point 5), the light is emitted toward the focusing lens 4. Then, the light incident on the condenser lens 4 passes through the same optical path as the light directly incident on the condenser lens 4, and is condensed on the liquid crystal panel 7.

[0031]

According to the present invention, as described above, the light from the light source can be made to enter the condenser lens by using the elliptical reflecting mirror and the plane reflecting mirror. In addition to this, light having no luminance unevenness can be incident on the condenser lens, and a high-luminance projection display device can be obtained.

[Brief description of the drawings]

FIG. 1 is a view showing a first embodiment of a projection type display device of the present invention.

FIG. 2 is a view showing a second embodiment of the projection display apparatus of the present invention.

FIG. 3 is a diagram showing a light source unit of a conventional projection display device.

FIG. 4 is a diagram showing a light emission distribution of a light source.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Elliptical reflector 3 Planar reflector 4 Condenser lens 5 First focus 6 Second focus 7 Liquid crystal panel 8 Opening 9 Virtual image 10 Spherical reflector 11 Projection lens

Claims (4)

[Claims] A light source; a first reflecting mirror formed so as to cover the light source; and a second reflecting mirror disposed on an opening surface of the first reflecting mirror.
A reflecting mirror, a condensing lens that receives light from the first and second reflecting mirrors and the light source and converts the light into substantially parallel light, and a transmission type light valve that receives light from the condensing lens and optically modulates the light with a video signal. And a projection lens for irradiating light modulated by the transmission type light valve, wherein the first reflecting mirror is arranged so that the light source has a first focal point, and The projection type display device, wherein the reflecting mirror is arranged so that a first focal point and a second focal point of the first reflecting mirror coincide with each other. 2. The projection type display device according to claim 1, wherein said first reflecting mirror has an elliptical shape. 3. The projection display device according to claim 1, wherein the second reflecting mirror has a planar shape. 4. The projection display device according to claim 3, wherein a central portion of said second reflecting mirror is spherical.