JPH0255384A - Projection type display device - Google Patents

Abstract

PURPOSE:To increase the quantity of light to be projected to a blue light screen and to improve the color balance of a device using a metal halide lamp as a light source by arranging a lens array body consisting of plural microlenses on the incident light side of a matrix type display element for transmitting blue light. CONSTITUTION:Light from the light source 102 using a metal halide lamp is divided into red(R), green(G) and blue(B) light components by a dichroic mirror 105 and respective components are made incident upon respective thin film transistor type liquid crystal display elements 101. The lens array body 111 formed so that picture elements correspond to microlenses at the rate of 1 to 1 to fixed to the light source side of the blue liquid crystal display element out of the elements 101. Thereby, the quantity of blue light to be transmitted can be increased about twice. Therefore, the intensity of blue light can be increased without dropping the intensity of red and green light at the time of using a high brightness lamp mainly using a metal halide lamp and color balance can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection type display device using a plurality of image forming matrix type liquid crystal display elements.

[Conventional technology]

One type of projection display device uses a liquid crystal display element. As shown in FIG. 7, the principle is that white light from a light source 102 is separated into red, green, and blue light, the amount of each light is controlled by a liquid crystal display element 101, and then optically combined and combined by a projection lens 109. This is a method of displaying image information on the screen 110.

Since a liquid crystal display element is a light-receiving type element, it does not emit light by itself, but displays image information by controlling the amount of transmitted light. In general, a liquid crystal display element requires light-absorbing polarizing plates to be placed before and after the element, so the efficiency of utilizing incident light is low and it can be said that it is a dark optical system. Therefore, the light source for a projection display device using a liquid crystal display element is required to be extremely bright, and halogen, xenon,
Lamps such as metal halide are used. Among them, metal halide lamps have high power consumption and high brightness compared to other lamps.

■Long lifespan.

(2) Since the light spectrum is m and nt, it can be separated into three primary colors with high efficiency.

It has excellent characteristics such as

[Problem to be solved by the invention]

However, the above-mentioned light sources, particularly metal halide lamps, generally have a low color temperature, and therefore have a drawback in that the intensity of blue light is relatively weak compared to red light and green light.

Although it is possible to increase the intensity of blue light by changing the active ion species and their composition ratio, in that case, (1) the lamp life will be shortened; ■ New problems such as a decrease in the brightness of the power consumption angle occur, and this does not result in a substantial improvement. Therefore, it is difficult to correct the color balance on the lamp itself, and in actual use, in order to maintain the color balance when displaying images, it is necessary to reduce the intensity of the red light and the edges, which eliminates the original excellent characteristics of the lamp. The problem was that it was not fully utilized.

Therefore, the present invention solves the above problems.
The purpose is to provide a projection display device that maintains the overall color balance and provides clear images without reducing the intensity of red and green light even when using a metal halide lamp as a light source. be.

[Means to solve the problem]

In order to solve the above problems, the projection display device of the present invention has the following features:
Three matrix-type liquid crystal display elements in which pixels are arranged in a matrix are irradiated with red, green, and blue light, which are the three primary colors of light, and the transmitted light from the liquid crystal display elements is optically synthesized. , a projection type display device that obtains image information by projecting the image, characterized in that a lens array body consisting of a plurality of microlenses is installed on the incident light side of a matrix type display element that transmits blue light. Further, the microlens and the pixel of the liquid crystal display element are arranged in a 1:1 correspondence.

[Effect]

According to the above means, the light incident on the blue light liquid crystal display element is focused on the liquid crystal pixel portion by the lens array consisting of a plurality of microlenses. Therefore, some of the incident light is removed by a light-shielding film provided on the liquid crystal pixel area (liquid crystal display elements equipped with active switching elements, which are commonly used in projection display devices, are used to protect the switching element area from strong light). In addition, the area other than the pixel aperture is covered with a light-shielding film.

), and almost all of the light passes through the liquid crystal pixel section, resulting in a very bright liquid crystal display element. In other words, the amount of blue light emitted to the screen is substantially increased, and it becomes possible to maintain the overall color balance without weakening the intensity of red light and green light.

〔Example〕

Hereinafter, the present invention will be described in detail based on Examples.

However, the present invention is not limited to the following examples.

[Example 1] Glass substrate with optically polished surface (BK-7, 40 mm
A distributed index flat plate microlens with a diameter of 100 μm and a focal length of 300 μm was formed on one side of a 30 mm x 1 mm surface using an ion exchange method with a pitch of 100 μm both vertically and horizontally. FIG. 3 schematically shows the arrangement of lenses. This lens array body can collect approximately 79% of the incident light.

FIG. 4 is a schematic plan view of a TPT (thin film transistor) active matrix liquid crystal display element used in a projection display device. X, Y matawax signal line 40
1,402, a thin film transistor 403, and a liquid crystal pixel portion 404, and this transistor applies a voltage between the pixel electrodes to control light transmittance. The pixel pitch is 100 μm in both the X and Y directions, and the pixel aperture is 50×50 μm2. Here, since the operating characteristics of the TPT element are significantly affected by external light, the area other than the liquid crystal pixel opening is generally covered with a light-shielding thin film. Therefore, the effective aperture ratio is 30-40%
It has a low and dark optical system.

FIG. 1 is a schematic configuration diagram of a projection type display device of the present invention.

Light 1 (102, metal halide lamp, Osram H
The light emitted from the T I 250W) is divided into red (R), green (G), and blue (B) by a dichroic mirror 105 for light separation.
The light is divided into two parts, each of which is divided into TFT type liquid crystal display elements 101.
incident on . Reference numeral 111 denotes the lens array body previously produced, in which pixels and microlenses are attached to the light source side of the blue light liquid crystal display element of this device in a 1:1 ratio. In this case, the substrate on the common electrode side of the liquid crystal display element (fifth
By reducing the thickness of the microlens 502 (Fig. 510),
It has a structure that allows easy optical coupling. By attaching this lens array to a TFT-type liquid crystal display element, it is possible to theoretically increase the amount of transmitted blue light by about twice. This is because the light collected by the microlens passes through the pixel opening 404 without being weakened by the light shielding layer of the liquid crystal display element. After the amount of transmitted light is controlled by a TFT type liquid crystal display element, each output light is combined into white light by a dichroic prism 108 for light synthesis, and is projected onto a screen 110 through a projection lens 109.

The spectrum of light on the screen obtained with the above configuration is shown by the solid line in FIG. In the figure, the spectrum when a conventional projection display device of the same type is used is also shown by a broken line. From FIG. 2, it can be seen that in the case of the present invention using a lens array, the intensities of red light and green light do not change, and only the intensity of blue light increases by about 1.7 times. Therefore, it is possible to maintain a good overall color balance without reducing the light intensity of red light and green light as in the conventional case.

[Example 2] A flat lens array having a lens arrangement as shown in FIG. 6 was fabricated on one side of a glass substrate whose surface was optically polished by the same method as in Example 1.

This lens array consists of unidirectional condensing linear lenticular lenses arranged with a vertical lens pitch of 100 μm, and this lens array can condense approximately 50% of the incident light. . The feature of this lens array is that, although its light collecting performance is inferior to that of the lens body of Example 1, it has excellent matching performance with the liquid crystal pixel aperture.

As in Example 1, this lens array body was incorporated in front of the blue light liquid crystal display element to construct a projection type display device. As a result, only the intensity of blue light has increased by about 1.4 times compared to the conventional projection display of the same type, making it easier to correct the color balance on the screen.

In each of the above embodiments, only one lens array body is attached to the light source side of the blue light liquid crystal display element, but another lens array body is attached to the projection lens side of the liquid crystal display element to control the output light. It may also be configured to suppress the spread angle. Further, the manufacturing method of the flat lens array used in the projection display device is not limited to the ion exchange method, but can also be manufactured by an electric field transfer method, a photopolymerization method, or the like.

Furthermore, the lens shape does not have to be flat, and may be a convex lens. In that case, an injection molding method or a press molding method is used. Furthermore, the liquid crystal display element is not limited to the TFT type, and MIM type liquid crystal display elements can also be used.

〔Effect of the invention〕

As explained above, the projection display device of the present invention increases the intensity of only the blue light and reduces the total light intensity without reducing the intensity of the red light and green light when using a high-intensity lamp, mainly a metal halide lamp. It is possible to maintain color balance without any problems. Therefore, unlike conventional projection display devices, there is no need to reduce the total light intensity to maintain color balance, or conversely, there is no need to use a brighter light source than necessary, resulting in an efficient and well-balanced projection display device. It is possible to do so.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the configuration of a projection display device according to the present invention. FIG. 2 is a diagram showing the spectrum of projected light on a screen. FIG. 3 is a schematic diagram of the arrangement of microlenses in the lens array used in Example 1. FIG. 4 is a pixel arrangement diagram of the TFT type liquid crystal display element used in Example 1. Figure 5 shows the TFT equipped with the lens array used in Example 1.
1 is a cross-sectional view of the structure of a type liquid crystal display element. FIG. 6 is a schematic perspective view of microlenses in the lens array used in Example 2. FIG. 7 is a schematic diagram of the configuration of a conventional projection display device.・Liquid crystal display element equipped with a lens array for sight correction...Lamp...Reflector...Interference filter...Dichroic mirror 101・・Transparent aperture・Incoming light・Outgoing light・Transparent substrate on the opposite electrode side・Lens substrate/embedded linear lenticule lens and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Masayoshi Kamikushi (and 1 other person) Light guide Zeta-two dichroic prism Glojection lens Screen・・Lens array 301 ・・・Circular microlens・・X signal line・・X signal line・Switching element・・Pixel electrode・・Plant lens array・Microlens・・TFT side transparent substrate・Switching element・・Pixel electrode・・Light-shielding film; m! CJlm) Figure +

Claims (2)

[Claims] (1) Three matrix-type liquid crystal display elements in which pixels are arranged in a matrix are irradiated with red, green, and blue light, which are the three primary colors of light, and the transmitted light from the liquid crystal display elements is optically A projection type display device that obtains image information by combining and projecting image information, characterized in that a lens array body consisting of a plurality of microlenses is installed on the incident light side of a matrix type display element that transmits blue light. Type display device. (2) A projection type display device, characterized in that the microlenses described in item 1 are installed in a 1:1 correspondence with pixels of a liquid crystal display element.