JPH04162081A - Projection display device - Google Patents

Abstract

PURPOSE:To attain thinness and lightness by reflecting projected images, emitted from two sets of projection optical systems, respectively by the surface and back face of one mirror, and projecting these reflected images respectively on two sets of screens. CONSTITUTION:An image projected from a first projection optical system 31 is reflected by a mirror 33, further reflected by the surface of a mirror 35 and projected on a screen 36. An image projected from a second optical system 32 is reflected by a mirror 34, further reflected by the back face of the mirror 35 and projected on a screen 37. That is, the images can be projected on both screens 36, 37 provided on both sides of a casing 30. Further thinness and lightness can be attained by providing the optical systems 31, 32 with liquid crystal projection displays.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) The present invention relates to a projection type display device using a CRT projection tube or a liquid crystal panel.

(Prior Art) In recent years, there has been an increasing demand for large-screen, thin and lightweight display devices, and along with this, development of projection-type liquid crystal display devices using liquid crystal panels has been actively conducted. By using this liquid crystal panel, it has become possible to make the display device thinner and lighter than a conventional projection display device using a CRT.

FIG. 4 is a block diagram showing the optical system of such a projection type liquid crystal display device, and FIG. 5 is a longitudinal sectional view of a conventional projection type liquid crystal display device. In FIG. 4, the light emitted from the light source 1 and the light emitted from the light source 1 and reflected by the reflector 2 are as follows:
The light is incident on a red-reflecting dichroic mirror 3, a green-reflecting dichroic mirror 4, and a blue-reflecting dichroic mirror 5, respectively. Then, the light is separated into three primary colors by the wavelength reflection characteristics of the mirrors 3 and 4.5, and is focused by field lenses 6, 7, and 8, respectively, to the R-axis liquid crystal panel 9, the G-axis liquid crystal panel 10. The light enters the B dynamic liquid crystal panel 11.

On the other hand, driving signals are supplied to each of the liquid crystal panels 9, 10, and 11 from a driving circuit (not shown). That is, the drive circuit generates R (red), G (green), and B (blue) signals based on the video signal, and sends these R, G, and B signals and the synchronization signal to the liquid crystal panels 9, 10, . 11 and is driven. As a result, each LCD panel 9.10.
11 emits R-axis, G-axis, and B-axis transmitted image light, respectively. The transmitted image light of these three axes is magnified by the R motion projection lens 12, the G axis projection lens 13, and the B axis trunk projection lens 14, respectively, and is then expanded by the first mirror 15 and the second mirror 16 as shown in FIG. The reflected light is optically synthesized on the screen 17 and an image is displayed.

When displaying images on the screens provided on both the front and back surfaces of the housing using the projection display device configured as described above, conventionally two projection display devices as shown in FIG. They were arranged symmetrically with the stand and screen facing outward. This slant depth was approximately twice that of a single unit, which had the disadvantage of increasing the size.

(Problem to be Solved by the Invention) As mentioned above, according to the conventional projection display device, when displaying images on the screens provided on both sides of the housing, the depth of the device is approximately twice as long as when displaying on one side. Therefore, there was a problem of increasing the size.

The present invention has been made in view of these points, and is a thin and
An object of the present invention is to provide a lightweight double-sided projection display device.

"Structure of the Invention (Means for Solving the Problems)" In order to achieve the above object, the present invention reflects a projected image emitted from a projection optical system by a mirror, and projects and displays this image on a screen. In a projection display device,
Two sets each of the projection optical system and the screen are provided, and the projected images emitted from the two sets of projection optical systems are each reflected by the front and back surfaces of one of the mirrors, and are respectively projected onto the two sets of screens. It is said that

Further, it is characterized in that a liquid crystal projection display device is used for the projection optical system.

(Function) According to the above configuration, since both the front and back surfaces of one mirror are used as reflecting mirrors for projecting images emitted from two sets of projection optical systems onto two sets of screens, it is possible to The number of mirrors that were previously required can be reduced to one, and the depth dimension of a double-sided projection display device can be made almost equal to that of a single-sided display, making the device thinner and lighter. Furthermore, the mirror can also serve as a light shielding function for the two sets of projection optical systems.

Furthermore, by using a liquid crystal projection display device as the projection optical system, the device can be made even thinner and lighter.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

An embodiment of the present invention is shown in FIGS. 1 and 2. FIG.

A first projection optical system 31 and a second projection optical system 32 are provided at the upper and lower parts of the cubic-shaped housing 30 of the device, respectively. These projection optical systems 31.3
2 have the same configuration as shown in FIGS. 4 and 5, respectively, and are RGB triaxial photographic lenses 12, 13.
The optical axes of 14 are parallel to the upper and lower surfaces of the housing 30, respectively. Furthermore, the emission directions of the image light are opposite to each other and are symmetrical with respect to a plane passing through the center of the housing 30 in the height direction.

Further, on the front surface of the projection optical system 31, 32 in the emission direction, there is a first mirror 33 inclined at a predetermined angle with respect to the respective optical axes.
A second mirror 34 is provided inside the housing 30, and is inclined at a predetermined angle with respect to a plane passing through the center in the height direction.
A third mirror 35 having reflective surfaces formed on both the front and back surfaces is provided. Further, a first screen 36 and a second screen are provided on both sides of the housing 30 facing the third mirror 35, respectively.
A screen 37 is provided.

According to the above configuration, the image projected from the first projection optical system 31 is reflected by the first mirror 33, further reflected by the surface of the third mirror 35, and is projected onto the first screen 36. Ru. Similarly, the image projected from the second projection optical system 32 is reflected by the second mirror 34, further reflected by the back surface of the third mirror 35, and is projected onto the second screen 37.

That is, the screen 3 provided on both sides of the housing 30
6. Images can be projected on 37.

According to this embodiment, the number of mirrors that conventionally required four mirrors can be reduced to three, making it possible to effectively utilize the space inside the housing 30 and making the device thinner. It is possible to achieve a reduction in shape and weight. This feature allows the installation area to be reduced, for example, when used as a display device for a round table conference or a display device for a competitive game machine. It can also be installed embedded in the wall between adjacent rooms to make effective use of living space.

In particular, by using liquid crystal projection display devices for the two systems of projection optical systems 31 and 32, it is possible to further reduce the thickness and weight.

FIG. 3 shows another embodiment of the invention. In this embodiment, the projection optical systems 31 and 32 are arranged inside both sides of the housing 30, and the mirrors 33, 34, and 35 are arranged in the projection optical systems 31 and 32, respectively.
It is arranged so as to face the optical axis of.

This embodiment also provides the same functions and effects as those of the embodiments described above.

In each of the above embodiments, the projection optical system uses a liquid crystal projection display device, but a CRT projection tube may also be used. Further, the two projection optical systems may have different configurations, and the screen sizes on both sides may be different.

``Effects of the Invention'' As explained above, according to the present invention, images emitted from two sets of projection optical systems are reflected by both the front and back surfaces of one mirror, and are projected onto two sets of screens. Therefore, the projection display device can be made thinner and lighter.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the structure of one embodiment of the present invention, Fig. 2 is a vertical sectional view, Fig. 3 is a perspective view showing the structure of another embodiment of the invention, and Fig. 4 is a projection type. FIG. 5 is a configuration diagram showing an example of an optical system of a liquid crystal display device, and FIG. 5 is a longitudinal sectional view showing an example of a conventional projection type liquid crystal display device. 31, 32...Projection optical system 35...Mirror 36, 37...Screen agent Patent attorney Nori Chika Ken Yudo Hiroshi Uji Figure 1 Figure 2 Figure 4 Figure 5

Claims (2)

[Claims] (1) In a projection display device that reflects a projected image emitted from a projection optical system by a mirror and projects and displays this image on a screen, two sets each of the projection optical system and the screen are provided, and the two sets of projection A projection type display device characterized in that a projected image emitted from an optical system is reflected by the front and back surfaces of one of the mirrors, and is respectively projected onto the two sets of screens. (2) The projection type display device according to claim 1, wherein a liquid crystal projection display device is used for the projection optical system.