JPH05323270A - Liquid crystal projector - Google Patents

Abstract

PURPOSE:To obtain the liquid crystal projector which can be given high resolution at low cost without increasing the number of pixels of a liquid crystal panel. CONSTITUTION:A 1st liquid crystal panel 8 and a 2nd liquid crystal panel 9 are so arranged that their images which are made incident on a screen 4 shift from each other by a half as much as the pixel pitch of the liquid crystal panels 8 and 9. The 1st panel 8 is supplied with a video signal of a 1st field and the 2nd liquid crystal panel 9 is supplied with a video signal of a 2nd field while they are switched by a signal switching circuit 10 at each vertical horizontal period, thereby driving the panels. Video signals obtained from the liquid crystal display panels 8 and 9 are put together to obtain an image having resolution of vertical pixels (scanning lines) twice as many as those of the liquid crystal panels 8 and 9 on the screen 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector device, and more particularly to a liquid crystal projector device which realizes a high resolution image without increasing the number of pixels of a liquid crystal panel.

[0002]

2. Description of the Related Art A liquid crystal projector device using a liquid crystal panel is known as a device that can easily achieve a larger screen than a CRT (cathode ray tube) system. An example of a conventional liquid crystal projector device will be described. FIG. 4 shows a single plate system using one color liquid crystal panel, and FIG. 5 shows a three plate system using three black and white liquid crystal panels for optical synthesis. 4 and 5, those having the same function are designated by the same reference numeral.

The basic principle of the single plate system shown in FIG. 4 is that the light from the light source lamp 1 is transmitted through the color liquid crystal panel 2 and the image on the color liquid crystal panel 2 is enlarged and projected on the screen 4 through the projection lens 3. This single plate method is RGB
Since three primary color filters (red, green, and blue) are generated on the liquid crystal panel, there are difficulties in achieving high resolution and high brightness.
The three-plate system improves these. The basic principle of the three-plate system shown in FIG. 5 is that the light from the light source lamp 1 is divided into three primary colors of RGB by the color separation filter 5, and an image of each RGB color is formed by passing through the monochrome liquid crystal panel 6 corresponding to each RGB. The colors are combined again by the color combining mirror 7 and projected onto the screen 4 by the projection lens 3. The resolution of the three-plate system is three times that of the single-plate system, and for example, when a 90,000-pixel panel is used, a resolution of about 300 lines can be obtained. Further, since a color filter having a large light absorption rate is not used, it is possible to prevent a decrease in brightness. However, in both the single plate system and the three plate system,
The number of pixels in the vertical direction of the liquid crystal panel used is only about half of the scanning lines of the television signal. Therefore, writing to the liquid crystal is performed for each field, and the odd field (first
The signals of the field) and the even field (second field) are written in the pixels on the same line.

[0004]

A higher resolution is required to support the interlaced scanning system, EDTV (Clear Vision), HDTV (High Definition Television), etc., and in order to realize the high resolution. Are required to drastically increase the number of pixels of liquid crystal panels. However, the quality is not stable due to the lack of pixels during fine processing of the liquid crystal panel, and the liquid crystal panel with a large number of pixels has a low brightness due to a decrease in the aperture ratio, which is expensive, and therefore the quality of the liquid crystal projector device itself is poor. There was a problem with that and the cost increased.

[0005]

In order to solve the above-mentioned problems of the conventional technology, the present invention transmits a light from a light source to a liquid crystal panel and projects an image on the liquid crystal panel by a projection lens. In, the image incident on the projection lens is ½ of the vertical pixel pitch.
First and second liquid crystal panels which are arranged so as to be incident to each other with a vertical shift and are driven by respective video signals, and odd field signals are supplied to the first liquid crystal panel, A signal switching circuit for supplying an even field signal to the second liquid crystal panel, and the first and second signal switching circuits.
And a synthesizing unit for synthesizing light transmitted through the liquid crystal panel to obtain image light.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal projector device according to the present invention will be described below with reference to the accompanying drawings. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a detailed diagram showing the vicinity of a liquid crystal panel of the present invention, and FIG. 3 is a diagram for explaining the principle of the present invention. 1 and 2, parts having the same functions as those in FIGS. 4 and 5 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, the light from the light source lamp 1 is divided into three primary colors of RGB by a color separation filter 5, and the light of each color of RGB is further divided into two. The light divided into two of each color of RGB is input to the first liquid crystal panel 8 and the second liquid crystal panel 9 corresponding to each of RGB. RGB
The first liquid crystal panel 8 and the second liquid crystal panel 9 corresponding to each are supplied with a video signal from a video signal circuit (not shown) (for simplification in the figure, RGB signals are shown).
A video signal of each color is omitted as it is supplied on one line.) A signal switching circuit 10 is provided between the video signal circuit and the first liquid crystal panel 8 and the second liquid crystal panel 9. ing. A total of 6 liquid crystal panels 8 for each RGB color,
Images of RGB colors obtained by passing through 9 are combined by the color combining mirror 7 and projected onto the screen 4 by the projection lens 3.

FIG. 2 is a detailed view of the vicinity of the liquid crystal panel.
Since the vicinity of each color liquid crystal panel corresponding to the GB signal has the same structure, only the structure near the liquid crystal panel for the R signal is shown, and the structure near the liquid crystal panel for the G and B signals is omitted. The R light separated by the color separation filter (not shown) is divided into two by the spectroscopic mirror 11 and the reflection mirror 13, and the first liquid crystal panel 8 and the second liquid crystal panel 9 are separated.
Is incident on. The first liquid crystal panel 8 and the second liquid crystal panel 9 are half the vertical pixel pitch of the liquid crystal panels 8 and 9.
Only in the vertical direction, the images are arranged and fixed so that the images are shifted and combined on the screen.

On the first liquid crystal panel 8, an odd field (first field) video signal is supplied to the second liquid crystal panel 9.
Is an even field (second field) video signal,
The signal switching circuit 10 switches and supplies in a vertical scanning cycle to drive. The lights that have alternately passed through the first liquid crystal panel 8 and the second liquid crystal panel 9 are combined by the reflecting mirror 13 and the light combining mirror 12 that are combining means. Further, the R image is combined with the G and B images obtained in the same manner by the color combining mirror 7 and is projected on the screen 4 by the projection lens 3.

Next, with reference to FIG. 3, an image projected on the screen 4 from the liquid crystal panels 8 and 9 is shown. As described above, the first liquid crystal panel 8 and the second liquid crystal panel 9 are
The images are arranged and fixed so that the images are combined with each other on the screen in the vertical direction by ½ of the vertical pixel pitch. In this state, odd-field video signals are input to the first liquid crystal panel 8, and even-field video signals are input to the second liquid crystal panel 9. At this time, an image is displayed on the first liquid crystal panel 8 and an image is displayed on the second liquid crystal panel 9. Therefore, the images are alternately projected in a state where the images are vertically displaced by 1/2 of the vertical pixel pitch of the liquid crystal panels 8 and 9. As a composite image is displayed on the screen 4, the image can be reproduced with the number of vertical pixels (the number of scanning lines) twice that of the liquid crystal panel used, and the vertical resolution can be increased. .. Further, although the three-plate system has been described in the embodiments, the single-plate system also has a similar configuration, which allows the liquid crystal projector device to have a higher resolution.

[0011]

As described in detail above, the liquid crystal projector device of the present invention is inexpensive and of high quality by combining a plurality of liquid crystal panels and a signal switching circuit without increasing the number of pixels of the liquid crystal panel. Even if a stable liquid crystal panel is used, the resolution can be improved, which is an extremely excellent practical effect.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a liquid crystal projector device of the present invention.

FIG. 2 is a detailed view showing the vicinity of the liquid crystal panel of the present invention.

FIG. 3 is a diagram for explaining the principle of the present invention.

FIG. 4 is a diagram showing a single plate method using one color liquid crystal panel.

FIG. 5 is a diagram showing a three-plate system in which three black-and-white liquid crystal panels are used to optically combine.

[Explanation of symbols]

 1 Light Source Lamp 3 Projection Lens 4 Screen 5 Color Separation Filter 7 Color Synthesis Mirror 8 First Liquid Crystal Panel 9 Second Liquid Crystal Panel 10 Signal Switching Circuit 11 Spectral Mirror 12 Photosynthesis Mirror (Synthesis Means) 13 Reflection Mirror (Synthesis Means)

Claims (1)

[Claims] 1. A liquid crystal projector device for transmitting light from a light source to a liquid crystal panel and projecting an image on the liquid crystal panel by a projection lens, wherein an image incident on the projection lens has a half of a vertical pixel pitch. Firstly arranged so as to be incident on each other with being shifted in the vertical direction, and to which respective video signals are supplied and driven.
And a second liquid crystal panel, a signal switching circuit that supplies an odd field signal to the first liquid crystal panel and an even field signal to the second liquid crystal panel, and the first and second liquid crystals. A liquid crystal projector device comprising: a light combining unit that combines light transmitted through a panel to obtain image light.