JPH0356922A - Liquid crystal projection display - Google Patents

Abstract

PURPOSE:To eliminate light loss and to achieve miniaturization, high brightness, low power consumption, and cost reduction by individually leading a light from each color light source to corresponding liquid crystal TV picture element. CONSTITUTION:The red light 4, the green light 5, and the blue light 5 from the red light source 1, the green light source 2, and the blue light source 3, respectively, are almost collimated by a lens 7, and are image-formed on the liquid crystal TV 9, which is a liquid crystal display element, by a microlens array 8. Each of the three color lights is modulated by an image signal in the liquid crystal TV 9, and is enlarged and projected by a lens 10. As it does so, with the lights which are transmitted through the microlens aray 8, the red light 4, the green light 5, and the blue light 6 are image- formed and condensed on a red picture element 9a, a green picture element 9b, and a blue picture element 9c, respectively. thus, the light can be modulated without losing the amounts of the lights from the corresponding light sources, and they are projected, by using three independent color light emitting sources 1-3, by forming a multiple image, of three color light from corresponding light sources, onto the liquid crystal TV 9 by means of an optical system, and by making the lights incident on the corresponding picture elements of the liquid crystal TV 9; additionally a small-sized, inexpensive liquid projector of low power consumption can be obtained.

Description

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

[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 S.
I Day (Proceeding or the S
．． I. D) 1192, pp. 375-378, ``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 two dichroic mirrors 30, and each light is reflected by a reflector 27, 28, 31. .32 and three LCD TVs (liquid crystal display elements) 21, 22.23
guided by. The light that has passed through each LCD TV is combined into a synthesis prism 2.
4, the images are combined into one, and the projection lens 33 enlarges and projects the images onto the screen.

[Problem to be solved by the invention]

Displays that project LCD TVs use white light sources such as halogen lamps and xenon lamps as light sources, but because the luminous efficiency is lower than that of the CRT used in CRT projection, the light source must be consumed to obtain high brightness. The high power required caused problems with heat dissipation from the device. especially,
Since the white light source includes infrared light, an optical filter that blocks the infrared light is used, but this is not sufficient, and the projected light significantly impairs the display performance of the liquid crystal TV. Furthermore, an optical system that separates white light into red, green, and blue light is required, which hinders miniaturization and cost reduction of the device. For this purpose, there is a simple LCD projection display that uses a white light source and a single-panel LCD TV with a color filter, but the amount of light that passes through the color filter is inevitably less than 1/3, making high-brightness projection impossible. It was hot.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a compact liquid crystal projection display that has high brightness and low power consumption.

[Means to solve the problem]

According to the present invention, one or more light sources that each emit light in a plurality of visible light regions, a lens that condenses the plurality of light in the visible light region, a microlens array, and a liquid crystal display element, A liquid crystal projection display is obtained, characterized in that the image of the light source formed by the 71 microlens array corresponds one-to-one with the aperture of the liquid crystal display element.

[Principle and operation of the invention]

In this invention, three independent light emitting light sources are used, a multiplexed image of the three colors of light from each light source is formed on the LCD TV using an optical system, and each image is incident on the three color pixels of the LCD TV. The amount of light from the light source can be modulated and projected without loss.

Therefore, it is possible to realize a small, low-cost, low-power consumption liquid crystal projector using a simple ellipse.

〔Example〕

FIG. 1 shows an embodiment of a liquid crystal projection display according to the present invention. The red light 4, green light 5, and blue light 5 from the red light source 1, green light source 2, and blue light source 3 are converted into approximately 1,000 lines of light by the lens 7, and are displayed on the liquid crystal TVQ, which is a liquid crystal display element, by the microlens array 8. imaged. Each of the three color lights is modulated by an image signal by the liquid crystal TV 9, and is enlarged and projected by the lens 10. FIG. 2 shows the optical paths of the light beams of each color in the liquid crystal TV in this case. In the light transmitted through the microlens array 8, the red light 4 forms an image on the red pixel 9a, the green light 5 forms an image on the green light 9b, and the blue light 6 forms an image on the blue pixel 9c. The LCD TV 9 has a transparent conductor on one transparent substrate 10! 11, a black matrix 13 and an alignment film 14 are arranged, and a thin film transistor array 17 and an alignment film 16 are arranged on the other transparent substrate 18.
It has a structure in which a liquid crystal is sandwiched between these transparent substrates 10 and 18. The liquid crystal TV 9 changes the light transmittance of each pixel 9a, 9b, 9C according to each color signal of the reimage signal, and intensity-modulates each color light 4, 5.6 transmitted through these pixels. The light transmitted through the liquid crystal TV is imaged on the screen by a lens that magnifies and projects these pixels. If the arrangement pitch of the microlens array 8 and the pitch of every three color pixels of the liquid crystal TV 9 are made equal, the above relationship can be established for all pixels of the liquid crystal TV 9.

As the light source, a CRT light source tube capable of emitting monochromatic light or a fluorescent light source tube can be used. Figure 4 shows CR
An example of a T-type light source tube is shown, with a heater 50, a cathode 49,
1st grid 44, 2nd grid 43, 3rd grid 4
2. A hyperfocusing lens 48 is included in the glass bulb 46. A fluorescent screen 41 is formed on the inside front of the glass bulb 46, and the glass bulb is attached to a base 45. In such a CRT type light source tube, an electron beam 47 from a cathode 49 is focused by a hyperfocusing lens 48 and irradiated onto a phosphor screen 41 to emit visible light. A high-intensity light source can be obtained because of the high energy conversion rate from electron beam to fluorescence. In addition, a three-color light source such as the one shown in FIG. 5 that separates a white light source 54 into three-color light with a dichroic prism 51 and returns the two-color light with reflectors 52 and 53 to obtain red light, green light, and blue light. It's okay.

The microlens array 8 may be a lens having a spherical shape as shown in FIG. 2, or a microlens array having a refractive index distribution by diffusing ions into a glass plate.

Furthermore, the same effect of the present invention can be obtained even if the liquid crystal TV 9 has a color filter configured for each color pixel in the same way as a conventional liquid crystal TV. Although the transmittance is lower than when each pixel is transparent, the effect of improving the saturation of each color can be expected. It is also possible to increase the projection efficiency by placing a microlens array with the same pitch as the microlens array 8 behind the liquid crystal TV in the projection optical system.

〔Effect of the invention〕

In this way, the light from the light source of each color is clearly guided to each pixel of the LCD TV corresponding to each color, so there is no loss of light, and a single-panel LCD TV can be used, making it compact and with high brightness. , low power consumption and low cost are obtained for LCD projection.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment according to the present invention, FIG. 2 is a diagram showing details of the optical system in the embodiment of the present invention, FIG. 3 is a diagram showing a conventional liquid crystal projector, and FIGS. The figure shows an example of a light source used in the present invention. 1, 2.3...Light source, 7.10...Lens, 8...
・Microlens array, 9...LCD TV.

Claims (1)

[Claims] one or more light sources that each emit light in a plurality of visible light ranges, a lens that condenses the light in the plurality of visible light ranges, a microlens array, a liquid crystal display element, and a light source that passes through the liquid crystal display element. 1. A liquid crystal projection display comprising a projection lens for projecting light onto a screen, wherein an image of the light source formed by the microlens array corresponds one-to-one with an aperture of the liquid crystal display element.