JPH03145294A - Liquid crystal projection display device - Google Patents

Abstract

PURPOSE:To attain color display on a single board liquid crystal by stimulating the light of each color light source synchronously with each color liquid crystal TV screen in time series. CONSTITUTION:Red light, green light and blue light respectively from a red light source 1, a green light source 2 and a blue light source 3 are almost collimated by lenses 7-9 respectively, each color light is propagated in the same direction by a polarization prism 10 and made incident in a liquid crystal TV 11. The liquid crystal TV 11 displays each color picture sequentially synchronously with the light sources, each color light is modulated by a picture signal and projected on the screen via the lens 12 with magnification. The light sources 1-3 are blinked sequentially by a light source drive circuit 20. Thus, one liquid crystal TV 11 is enough, the number of display picture elements is not decreased due to color display, the high picture element display is implemented and the equipment is made small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection display using a liquid crystal panel.

[Conventional technology]

In recent years, there has been a desire to realize large-screen, high-definition televisions. CRT projection is currently available as a device for realizing this, but it has not yet become widespread for home use because it is large-scale and expensive. As a device for realizing a large screen display at a low cost, there is a method of projecting a liquid crystal TV. This method is described in the magazine Proceedings of the Varnish, for example.
I Day (Proceeding of the S
, 1. D) Paper published in J1982, pp. 375-378 [LCD Full-Color Video Projector (LCD Full-Color Video Projector)
Projector) 4. According to this paper, a large screen display is possible by projecting an enlarged image displayed by inputting projection light onto a liquid crystal TV as shown in FIG. In FIG. 3, white light from a light source 25 passes through a lens 26 and is separated into three colors, red, blue, and green, by a dichroic mirror 29.30, and each light is reflected by a reflecting mirror 27, 28, 31, and 32. After that, it is led to three LCD TVs 21°22.23. The lights passing through each liquid crystal TV are combined into one by a combining prism 24 and enlarged and projected onto a screen by a projection lens 33.

[Problem to be solved by the invention]

In order to display color on a display that projects an LCD TV, it is sufficient to project an LCD TV that has each red, green, and blue pixel, but because the number of each pixel is small, it is difficult to display images with sufficient image quality. For this purpose, separate liquid crystal TVs are prepared for each of the three primary colors, and images of each color are combined to display a color display. In this case, three liquid crystal TVs are required, making it difficult to reduce the price and size.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide a compact liquid crystal projection display with a single liquid crystal TV panel and a high number of pixels.

[Means to solve the problem]

According to the present invention, a plurality of light sources each emitting light in a plurality of visible light regions, a light source drive circuit that sequentially blinks these light sources in chronological order, and a light source driving circuit that condenses the plurality of light in the visible light region. A liquid crystal projection display is obtained that includes a lens, a liquid crystal display element, a liquid crystal drive circuit that sequentially displays a screen corresponding to the emission color of the light source on the liquid crystal display element in synchronization with the light source drive signal, and a projection lens. .

[Principle and operation of the invention]

In this invention, three independent light emitting light sources are used, and the three colors of light from each light source are sequentially irradiated onto a liquid crystal TV by an optical system, and enlarged and displayed by a projection optical system. A liquid crystal TV displays red pixels when the light source is red, displays green pixels when the light source is green, and displays blue pixels when the light source is blue. Therefore, only one liquid crystal TV is required, the number of display pixels does not decrease due to color display, high pixel display can be performed, and the device can be made compact.

〔Example〕

FIG. 1 shows an embodiment of a liquid crystal projection display according to the present invention. Red light source 1. Green light source 2. Each red light, green light, and blue light from the blue light source 3 is turned into substantially parallel light by the lens 7.8.9, and the light of each color travels in the same direction by the polarizing prism 10 and enters the liquid crystal TVII. The liquid crystal TVII displays images of each color sequentially in synchronization with a light source, and each color light is modulated by an image signal and is enlarged and projected onto a screen by a lens 12.

Each light source 1.2.3 is sequentially blinked by the light source drive circuit 20, for example, in a red, green, blue cycle, and in order to avoid flickering, this cycle time should be 30m5 or less. There is a need. The light source is a fluorescent light source, C
An RT light source can be used. LCD T■11 is LCD T
Although the display is performed by the V drive circuit 21, the liquid crystal TV drive circuit 21 is configured to display red when the red light source is lit in synchronization with the light source drive circuit 20.

The same applies to green and blue. LCD TV drive circuit 21
It is necessary to drive the liquid crystal TV at a higher speed than before, for example, at 10 m5. For this purpose, the liquid crystal TV drive circuit 21 has a frame memory for each color pixel, once stores a time-series image signal for each color, and sends the image signal to the liquid crystal TV in synchronization with the light source for display.

FIG. 2 shows the temporal relationship between the light emission of each of the red, green, and blue light sources 1, 2.3 and the display on the liquid crystal T11.

Red light source 1. Green light source 2. The blue light sources 3 sequentially emit light, and the liquid crystal TV 11 displays a screen of each color within each light emission time.

〔Effect of the invention〕

In this way, since the light from the light source of each color is emitted in chronological order in accordance with the LCD TV screen of each color, single-panel LCD TV
It is possible to display color in small size, high brightness, low power consumption, and low cost LCD projection.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the timing of light emission from a light source and display on a liquid crystal TV in an embodiment of the present invention, and FIG. 3 is a diagram showing a conventional liquid crystal projector. FIG. 1... Red light source, 2... Green light source, 3... Blue light source, 7.8.9... Lens, 10... Polarizing prism, 11... Liquid crystal TV, 20... Light source drive circuit, 21・
...LCD TV drive circuit.

Claims (1)

[Claims] a plurality of light sources that each emit light in a plurality of visible light regions; a light source drive circuit that sequentially blinks the light sources in chronological order;
a lens for condensing light in the plurality of visible light regions, a liquid crystal display element, and a liquid crystal drive circuit for sequentially displaying a screen corresponding to the emission color of the light source on the liquid crystal display element in synchronization with the light source drive signal. , a projection lens.