JPH01180587A - Light leading system of projection type display device - Google Patents

Abstract

PURPOSE:To improve the coefficient of utilization of a luminous flux by converging rays of light to the section at which a video is displayed only by reflecting the rays of light by means of a concave mirror or passing the rays of light through a convex lens. CONSTITUTION:A concave mirror 1 which reflects rays of light and a convex lens 2 which converges rays of light are provided. The collimate rays of light condensed by the reflection of the mirror 1 are used to illuminate the section at which the video of a panel is displayed only and the rays of light converged by the convex lens 2 are also used to illuminate the section at which the video of the panel is displayed only. Since the rays of light is converged by using the concave mirror 1 and convex lens 2 in such way, the coefficient of utilization of the luminous flux is improved and a bright projected video can be obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a light guide method for a projection display device.

[Conventional technology]

As shown in the conventional example diagram in Fig. 4, the conventional light guide method is provided at the rear of the lamp (20) or collimated light is obtained by the action of a flefter (21) or lens (22), and a flat plate-shaped light guide system is used. The light was guided by passing through or reflecting through the guichroic mirror (23) and the reflecting mirror (24).

[Problem that the invention seeks to solve]

However, the conventional light guiding method has the problem that even areas that do not require illumination are illuminated, making it impossible to make efficient use of the luminous flux. This is because the part of the panel that displays images is often located in the center of the panel, and there are drive circuits, etc. around the periphery of the panel, which ends up illuminating the periphery of the part other than the part that displays images. be.

The present invention is intended to solve these problems, and its purpose is to provide a light guide method that concentrates light only on the area where an image is displayed, increasing the utilization rate of the luminous flux.

[Means for solving problems]

The light guide system of the projection display device of the present invention includes three transmissive panels, each of which is illuminated with light of the three primary colors of red, green, and blue, and images from the three transmissive panels are combined and projected. The display at is characterized by comprising a reflecting means for reflecting light by a concave mirror and a means for condensing the light by a convex lens.

[Effect]

According to the above-described configuration of the present invention, the collimated light is reflected by the concave mirror, so that the light is condensed and only the portion of the panel where the image is displayed can be illuminated.

Further, the light condensed by the convex lens can illuminate only the portion of the panel where the image is displayed, as described above.

In this way, by condensing light using a concave mirror and a convex lens, the utilization rate of the luminous flux is increased and a bright projected image can be obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a principle diagram of the light guide system, and FIG. 2 is an internal perspective view of the light guide unit.

A light beam emitted from a light source (7) such as a halogen lamp or a xenon lamp is condensed by a lens (8) and enters the casing (10) of the light guide unit as collimated light. The purpose of the heat ray cut filter (9) is to cut the infrared part of the light to prevent heat from being transmitted to the inside of the light guide unit.

The incident collimated light is reflected by the blue reflective mirror (4B) and only the blue component of the light is reflected by the concave mirror (1).
) to illuminate the blue liquid crystal panel (3B). The orange light that has passed through the blue-reflecting guichroic mirror (4B) is reflected by the green-reflecting guichroic mirror (4G), where only the green component is reflected, and passes through the convex lens (2) to the green night crystal panel (3G). illuminate.

The red light transmitted through the green reflective mirror (4G) is reflected by the red reflective mirror (4R), passes through the concave mirror (1), and illuminates the red liquid crystal panel (3R). Here, the red reflective guichroic mirror (4R)
is used to improve the color purity of red light,
If color purity is not an issue, a simple reflecting mirror may be used.

Red LCD panel (3R) and blue LCD panel (3B)
A concave mirror (1) is placed immediately in front of the mirror. When the collimated light is reflected by the concave mirror (1), the collimated light is condensed and illuminates the panel.

A convex lens (2) is placed just in front of the green liquid crystal panel (3G). When the collimated light passes through the convex lens (2), it is condensed and illuminates the green liquid crystal panel (3G).

Since both the concave mirror (1) and the convex lens (2) have the function of condensing light, by appropriately selecting their focal lengths, it is possible to condense light only on the part of the panel where the image is displayed.

The cube prism (5) is made by laminating four dichroic films on the slopes of a right angle prism.

Red LCD panel (3R) and blue LCD panel (3B)
The image displayed in
The image displayed on the 3G) passes through the cube prism (5) and reaches the projection lens (6).

The cube prism (5) combines images from three liquid crystal panels by reflecting or transmitting them, and the combined image is enlarged and projected by a projection lens (6).

FIG. 3 is a layout diagram of another embodiment, and is an example in which the cube prism (5) is not used.

In the embodiment described above, the purpose was achieved by using two concave mirrors and one convex lens, but in the other embodiment shown in FIG.
The purpose is achieved using one concave mirror and two convex lenses.

Furthermore, image synthesis is also performed using a combination of dichroic mirrors and reflective mirrors.

〔Effect of the invention〕

As described above, according to the present invention, light can be focused by reflecting it with a concave mirror or transmitting it through a convex lens.

At this time, by appropriately selecting the focal length of the concave mirror or convex lens, it is possible to illuminate only the part of the panel where the image is to be displayed, so that the luminous flux can be used for operation and a bright projected image can be obtained.

[Brief explanation of the drawing]

Figure 1 is a diagram of the principle of the light guiding method. FIG. 2 is an internal perspective view of the light guide unit. FIG. 3 is a layout diagram of another embodiment. FIG. 4 is a diagram of a conventional example. 1... Concave mirror 2... Convex lens 3R... Red liquid crystal panel 3G... Green liquid crystal panel 3B... Blue liquid crystal panel 4R... Red reflective guichroic mirror 4G... Green reflective Guicroic mirror 4B... Blue reflection Guicroic mirror 5... Cube prism 6... Projection lens 7... Light source 8... Lens 9... Heat ray cut filter 10... Housing 11 ...reflector or more Applicant: Seiko Epson Co., Ltd. (Fig. 1, Fig. 2)

Claims (1)

[Claims] In the light guiding method of a display device that has three transmissive panels, each illuminated with light of the three primary colors of red, green, and blue, and projects the combined images of the three transmissive panels, a concave mirror is used to direct the light. 1. A light guide system for a projection display device, comprising a reflecting means for reflecting light and a means for condensing light using a convex lens.