JPS62170931A - Stereoscopic projector - Google Patents

Abstract

PURPOSE:To attain stereoscopic display of an image by setting up the polarizing axes of polarizing plates in two liquid crystal displays arranged oppositely to the same screen so that both the axes are shifted by 90 deg. to each other and irradiating images from the back side. CONSTITUTION:Two liquid crystal displays 11A, 11B are arranged oppositely to the screen 10. The polarizing axes of the polarizing plates 23A, 23B on the displays 11A, 11B are set up so as to be shifted each other by 90 deg., light sources 13A, 13B for irradiating images on the displays 11A, 11B and projecting them on the screen 10 are arranged on the back of the displays 11A, 11B and image forming optical systems 14A, 14B are arranged in front of the displays 11A, 11B. Polarizing glasses for observing the images projected on the screen 10 are prepared. An image signal control part 12 sends image signals for right and left eyes which have visual differences respectively to the displays 11A, 11B to display the images by controlling voltages to be applied to electrodes. Consequently, the images are observed as a solid image.

Description

[Detailed description of the invention] Technical field The present invention relates to a stereoscopic projection device.

BACKGROUND OF THE INVENTION In recent years, with the development of computers and their software, various displays, CAD/CAM, and computer graphics (CG) have become commonplace. In this context, it is thought that there is plenty of room to encourage the further development of 3D video and to improve the image quality in order to create a powerful and realistic feeling on the screen. From this point of view, various stereoscopic image display methods have been proposed and developed. Here, as a specific example of a method for stereoscopically displaying an ordinary film image, polarized glasses are often used, as shown in, for example, Japanese Utility Model Application Publication No. 59-63357.

As shown in FIG. 6, the stereo slide mount 1 includes a stereoscopic left-eye photograph 2L.
and a photograph 2R for the right eye are set, and their images are projected onto the screen 3 by a lamp. Here, the lens system for imaging the left and right photographs 2L+2R includes polarizing filters 4L+4 whose polarization axes are different by 90 degrees.
R is provided respectively. Then, by wearing the polarized glasses 5, the viewer can distinguish between the images projected from the stereo slide projector 6 onto the screen 3, whose polarization axes match, with the left and right eyes. However, this method is for stereoscopic projection of images expressed on film like photographs, and is not for stereoscopic viewing of images displayed on a display or television screen.

In this regard, methods for viewing a display or television screen stereoscopically include methods that employ one type of electronic shutter or, for example, as shown in Japanese Patent Laid-Open No. 58-184929, a polarizing plate is provided for each display element. There is something. but,
Such a system is a direct viewing type in which an image displayed on a color CRT or the like is viewed as a three-dimensional image, and in the case of a CRT, the display device is large in size. Furthermore, in order to increase the screen size, it is necessary to increase the size of the CRT itself, and at the same time, the screen size cannot be changed freely.

Purpose The present invention has been made in view of the above points, and has a small and inexpensive structure, the screen size can be easily changed, and images can be displayed three-dimensionally using CAD/CAM, CG, etc. The purpose is to obtain a three-dimensional projection device.

Structure In order to achieve the above-mentioned object, the present invention includes two liquid crystal displays that include two polarizing plates with a liquid crystal interposed between them and display an image by inputting an image signal to an electrode, which are arranged facing each other on the same screen. The polarizing axes of the polarizing plates of these two liquid crystal displays are set to be shifted by 90 degrees between the two liquid crystal displays, and a light source is provided that illuminates the images of these liquid crystal displays from behind and projects them on the screen. It is characterized by:

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. First, FIG. 1 schematically shows the basic structure of the present invention. First, a screen 1o is provided, and two liquid crystal displays IIA and IIB are provided facing the screen 1o. The structure of this liquid crystal display 11 will be described later, but it displays an image in response to an image signal from an image signal control section 12. Moreover, these liquid crystal displays 11A.

The polarization axes of 11B are set to be offset by 90' from each other, and the rear of each is irradiated with light to display a liquid crystal display II.
Light sources L3A and 13B are provided for projecting images on A and 11B onto the screen 10, and imaging optical systems 14A and 14B are provided in front. Polarized glasses 15 are provided for the viewer to view the image projected onto the screen 10.

Here, the structure of the liquid crystal display 11 is shown in FIG. First, the liquid crystal 16 is connected to the light distribution films 17 and 18 and the filter 19.
and individual electrodes 20 and common electrodes 21 for R, G, and B colors.
These are sandwiched between two polarizing plates 22 and 23 whose polarization axes are the same. Such a liquid crystal display 11
Light is emitted from the light source 13 from the polarizing plate 22 side. Then, by applying a voltage to the electrodes 20 and 21 in accordance with the image signal, that portion becomes translucent, and the light from the light source 13 is transmitted and projected onto the screen 10. Liquid crystal display 1 shown in Figure 1
1^ and 11B both have the same structure as shown in FIG. 2, but their polarization axes are shifted by 906.

In Figure 1, it is representatively shown that the polarization axes of the polarizing plates 23A and 23B located on the viewing surface side are shifted, but correspondingly, the polarization axes of the polarizing plates and light distribution plate on the other side are also in the same direction. It is set so that These liquid crystal displays 11^, 11B receive signals from the image signal control section 12,
Image signals with parallax for the right eye and for the left eye are sent, voltage application to the electrodes is controlled, and the images are displayed.

In other words, the liquid crystal display IIA with parallax
, IIB are projected onto the screen 10 by the light sources 13A and 13B with their polarization axes shifted by 90". An observer wears polarized glasses 15 to view the projected images on the screen 10. By viewing images with aligned polarization axes with the left and right eyes, they are visually perceived as a three-dimensional image.

Based on this principle, the device is specifically constructed as shown in FIGS. 3 and 4. That is, the light source 13, the liquid crystal display 11, and the imaging optical system 14 are integrated as a projection device 24. More specifically, the light source 13 and the liquid crystal display 11 are provided within a main body cover 25, and the imaging optical system 14 is provided within an optical system cover 26 that can be attached to and removed from the main body cover 25 by screwing. And light source 13
A reflecting mirror 27 is provided on the back surface of the device, and a cooling fan 28 for preventing heating by the light source 13 is provided. Further, a condenser lens 29 is provided between the light source 13 and the liquid crystal display 11. And light source 13
Power is supplied to the liquid crystal display 11 and image signals are supplied to the liquid crystal display 11 from another unit, and the light source socket 30 and liquid crystal connector 31 of the connection layer are provided in a protruding state. Further, a screw 633 for fixing to the fixing base 32 is formed at the center of the bottom surface of the main body cover 25. Furthermore, the imaging optical system 14 has a focus adjustment function based on the projection distance, and its focus adjustment knob 34 protrudes from the optical system cover 26. As shown in FIG. 4, such projection devices 24 are arranged side by side on a fixed base 32 as 24A and 24B. In this case, the liquid crystal displays IIA, I of each projection device 24^, 24B
It is necessary to use IBs whose polarization axes differ by 90',
In order to clarify the direction of this polarization axis, each projection device 2
4^, on the cover of 24B is a sticker 3 indicating the polarization axis direction.
5^, 35B is attached. This does not necessarily have to be a sticker; any display that is easy for the user to understand is sufficient.

Note that these projection devices 24A, 24. The screen 10 on which the image is projected is preferably a silver screen. That is, if the screen is not a silver screen, the polarization of the light reflected by the screen will be lost, and it will be impossible to separate the two screens on the screen, making it impossible to view stereoscopically.

As described above, according to this embodiment, since the image from the image signal control section 12 is displayed on the floodlight type liquid crystal display 11^, 11B, the image quality is significantly reduced compared to the case where a color CRT or the like is used. Can be made smaller and thinner 6
Furthermore, since images are projected onto the screen 10 by the light projection type liquid crystal displays 11A and IIB, the size of the screen can be easily changed, and the screen can be made larger. Further, the devices shown as the projection devices 24^, 24B, etc. are also inexpensive, and the polarized glasses 15 for viewing the image on the screen 10 are also inexpensive, so that the overall configuration can be made at low cost. Furthermore, since the image is projected onto the screen 10, a relatively large number of people can view the image as a three-dimensional image at the same time. In addition, there is no need to add additional polarizing filters 4L and 4R to the stereo slide projector 6 as in the case of FIG. 6, and it is sufficient to use liquid crystal displays 11^ and 11B having polarizing plates 22 and 23. be. Furthermore, liquid crystal display I
The liquid crystal used in IA and IIB is twisted nematic (TN) mode, and each pixel is
Driven by N/OFF. An active matrix method can be adopted as the driving method, and it can support video display. Liquid crystal display IIA, II
The image signal to B is an electrical signal, and it can be easily applied to computer graphics (CG).

In addition, in this embodiment, the liquid crystal display 11^.

Although light sources 13^ and 13B were provided separately for 11B,
One light source may be provided in common for the liquid crystal displays IIA and IIB. In addition, as shown in FIG. 5, the liquid crystal cover 35 for the liquid crystal display 11 portion is separated from the main body cover 25 and is freely rotatable, so that the light source portion from the light source 13 to the condensing lens 29 and only the liquid crystal display 11 are separated. 3 in the display section and the optical section containing only the imaging optical system 14.
It may be divided to provide versatility as a device.

In other words, one projector can be configured as a wide variety of displays depending on the application. For example, the projection device 24
If one unit is used alone and the optical system cover 26 is removed from the main body cover 25, it can also be used as a direct viewing type. At this time, it is preferable to provide a light amount adjustment knob for adjusting the light amount of the light source 13. This is because in the case of a direct viewing type, the amount of light that remains as in the projection type would be dazzling. Even when changing to such a direct view type, there is an advantage that the liquid crystal display 11X is divided by a liquid crystal cover 35 as shown in FIG.

In other words, if the projection type remains, when looking directly at the image displayed on this liquid crystal display 11, it will appear that the design of the imaging optical system 14 has been improved. This is because the orientation can be changed by rotating the liquid crystal display 11 by freely mounting it.

Effects As described above, the present invention displays an image according to an image signal on two liquid crystal displays in which the polarization axes of the polarizing plates are shifted by 90 degrees, and projects this image onto a screen using a light source. Color C image according to the signal
It can be made smaller and thinner than when displayed on an RT, etc., and since it is a projection method on a screen, it can easily handle changes in screen size, making it possible to increase the screen size. Images on such screens can be viewed with polarized glasses and are inexpensive, and since liquid crystal displays display images using electrical signals, they can be easily used as stereoscopic displays for computer graphics.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a schematic perspective view showing the principle of an embodiment of the present invention;
Fig. 2 is a cross-sectional view of the liquid crystal display, Fig. 3 is a longitudinal side view showing the structure as a projection device, Fig. 4 is an external perspective view,
FIG. 5 is a longitudinal sectional side view showing a modified example, and FIG. 6 is a perspective view showing a conventional example. 10... Screen, 11 people, IIB... Liquid crystal display, 13... Light source, 16... Liquid crystal, 22.2
3...Polarizing plate Applicant: Ricoh Co., Ltd. - Agent: Akira AikijHJl, B,,l:!゛、′、
,. ,-,YUI,::DoJ,Fig.6

Claims (1)

[Claims] Two liquid crystal displays including two polarizing plates with a liquid crystal interposed between them and displaying images by inputting image signals to electrodes are provided facing each other on the same screen,
The polarization axes of the polarizing plates of these two liquid crystal displays are set to be shifted by 90 degrees between them, and a light source is provided that illuminates the images of these liquid crystal displays from behind and projects them onto the screen. A three-dimensional projection device.