JPH0728016A - Projection type liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a projection type liquid crystal display panel capable of projecting the whole image displayed on a liquid crystal display panel on a projection screen without enlarging the diameter of a reflector than the size of the liquid crystal display panel. CONSTITUTION:A back light device 33 by which the liquid crystal display panel 2 is irradiated with an illuminating light is constituted of a metal halide lamp 4, the spherical reflector 5 whose center coincides with the light emitting point of the metal halide lamp 4, a paraboloid reflector 6 whose focal point coincides with the center of the spherical reflector 5 and a convex lens 7 arranged on the center of the paraboloid reflector 6 and whose rear side focal point is made to match with the center of the spherical reflector 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device of this type includes a projection lens, a liquid crystal display panel for displaying an image projected on a projection surface by the projection lens, and a parabola for illuminating the liquid crystal display panel with illumination light. And a surface reflector, and a metal halide lamp as a light source is provided inside the parabolic reflector.

The metal halide lamp has a pair of electrodes to which an AC voltage is applied and emits light from the vicinity of these electrodes. Therefore, if the parabolic reflector is focused near the electrodes of the metal halide lamp,
Since the illumination light from the parabolic reflector does not enter the central portion of the liquid crystal display panel and the light source is shaded at the center of the projection surface, in the above-mentioned projection type liquid crystal display device, the light from the parabolic reflector is emitted. The focal point of the parabolic reflector is arranged between the electrodes of the metal halide lamp so that the illumination light is slightly condensed with respect to the optical axis.

[0004]

However, when the focal point of the parabolic reflector is arranged between the electrodes of the metal halide lamp, the illumination light is incident on the central portion of the liquid crystal display panel, so that the shadow of the light source is projected in the center of the projection surface. Although the problem of occurring is solved, there is a problem that the aperture of the parabolic reflector must be larger than that of the liquid crystal display panel in order to project the entire image displayed on the liquid crystal display panel on the projection surface. .

The present invention has been made in view of the above problems, and an object thereof is to project the entire image displayed on the liquid crystal display panel on the projection surface without making the aperture of the reflector larger than that of the liquid crystal display panel. Another object of the present invention is to provide a projection type liquid crystal display device that can be manufactured.

[0006]

In order to solve the above problems, the present invention provides a projection type liquid crystal comprising a projection lens and a liquid crystal display panel for displaying an image projected on a projection surface by the projection lens. In the display device, an illumination light irradiating means for illuminating the liquid crystal display panel with illumination light, a light source, a spherical reflector centered on a light emitting point of the light source, and a parabolic surface focused on the center of the spherical reflector. It is characterized in that it is composed of a reflector and a convex lens which is arranged at the center of the parabolic reflector and has a rear focus on the center of the spherical reflector.

[0007]

In the present invention, when the light emitted from the light source hits the spherical reflector, the light hitting the spherical reflector enters a convex lens, and the lens action of this convex lens makes the light parallel to the optical axis. Is incident on the central part of. When the light emitted from the light source hits the parabolic reflector, the light hitting the parabolic reflector becomes light parallel to the optical axis and is incident on the peripheral portion of the liquid crystal display panel.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are views showing an embodiment of the present invention, and FIG. 1 is a view showing a schematic configuration of a projection type liquid crystal display device according to an embodiment of the present invention. In the figure, reference numeral 1 is a projection lens, and a liquid crystal display panel 2 is provided behind the projection lens 1.
Is provided.

The liquid crystal display panel 2 displays an image projected on a projection surface (not shown) by the projection lens 1, and a backlight device 3 as an illumination light irradiating means is provided on the rear side of the liquid crystal display panel 2. It is provided.

As shown in FIG. 2, the backlight device 3 includes a metal halide lamp 4 as a light source, a hemispherical spherical reflector 5 whose center O coincides with a light emitting point of the metal halide lamp 4, and a spherical reflector 5. And a parabolic reflector 6 whose focal point coincides with the center O of the convex reflector 7. . In the figure, reference numeral 8 is a holding member for holding the convex lens 7 at the center of the parabolic reflector 6, and the holding member 8 is made of a transparent material.

According to this structure, part of the light generated at the light emitting point of the metal halide lamp 4 strikes the spherical reflector 5, passes through the center O of the spherical reflector 5, and enters the convex lens 7. The light that has entered the convex lens 7 becomes light parallel to the optical axis, exits from the convex lens 7, and enters the central portion of the liquid crystal display panel 2. On the other hand, the rest of the light generated at the light emitting point of the metal halide lamp 4 hits the parabolic reflector 6, becomes light parallel to the optical axis, and enters the peripheral portion of the liquid crystal display panel 2.

Therefore, in one embodiment of the present invention, the illumination light can be made incident on the entire panel surface of the liquid crystal display panel 2 without condensing the illumination light applied to the liquid crystal display panel 2. The entire image displayed on the liquid crystal display panel can be projected on the projection surface without making the aperture of the reflector larger than that of the liquid crystal display panel. Although the metal halide lamp is used as the light source in the above-described embodiment, the same effect can be obtained by using the xenon lamp as the light source.

[0013]

As described above, according to the present invention, the illumination light irradiating means for irradiating the liquid crystal display panel with the illumination light is provided with a light source.
A spherical reflector centered on the emission point of this light source,
Since the parabolic reflector focused on the center of this spherical reflector and the convex lens that is placed in the center of this parabolic reflector and has its rear focus on the center of the spherical reflector, the aperture of the reflector can be reduced. It is possible to provide a projection type liquid crystal display device capable of projecting the entire image displayed on the liquid crystal display panel on the projection surface without making the size larger than the liquid crystal display panel.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a projection type liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is an operation explanatory view of the same embodiment.

[Explanation of symbols]

 1 ... Projection lens 2 ... Liquid crystal display panel 3 ... Backlight device 4 ... Metal halide lamp 5 ... Spherical reflector 6 ... Parabolic reflector 7 ... Convex lens

Claims (1)

[Claims] 1. A projection type liquid crystal display device comprising a projection lens and a liquid crystal display panel for displaying an image projected on a projection surface by the projection lens, wherein the liquid crystal display panel is illuminated with illumination light. A light source, a light source,
A spherical reflector centered on the emission point of this light source,
A projection type comprising a parabolic reflector focused on the center of the spherical reflector, and a convex lens arranged in the center of the parabolic reflector and focused on the rear side of the center of the spherical reflector. Liquid crystal display device.