JPS62254589A - Projection type color display device - Google Patents

Abstract

PURPOSE:To obtain a high brightness and bright projection video even by a dark projection lens of small aperture ratio by using a Koehler system illumination. CONSTITUTION:A halogen lamp 22 is placed in the vicinity of the focal point of a converging lens A24 and forms a light source together with a reflector 23. A liquid crystal panel 28 is disposed slightly outside the focal distance of the projection lens 20 and the enlargement ratio of the projection video is varied by varying the position of the projection lens 20. The video displayed on the liquid crystal panel 28 is illuminated by the Koehler system illumination device, so that the light in which the quantity of transmission is controlled by the liquid crystal panel 28 is efficiently made incident on the projection lens 20 and the bright projection video of the high brightness can be obtained even by the dark projection lens 28 of the small/aperture ratio.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the configuration of a projection type color display device.

[Summary of the invention]

The present invention provides a projection type color display device in which the three primary colors of light are obtained using a Koehler illumination device and a color filter, and three liquid crystal panels in which thin film transistors are integrated in a matrix are illuminated to produce a primary color corresponding to each of the three primary colors of light. By color-combining the images on the LCD panel displayed using signals using a dichroic mirror and displaying the images on the screen using a projection lens, we aim to improve lighting efficiency and achieve high brightness and bright projection even with a dark projection lens with a large F value. This allows images to be obtained.

[Conventional technology]

A conventional projection type color display device is shown in FIG.

In the conventional example shown in FIG. 7(a), images from three cathode ray tubes 100, which display images in monochrome colors of red, green, and blue, are combined and displayed on a screen 102 using three projection lenses 101.

In addition, the conventional example shown in Fig. 7 (b) has three black and white cathode ray tubes.
03 image with red, green, and blue color filters 10
After color separation by 4, dichroic mirror 105
The colors are combined and displayed on the screen using the projection lens 106.

[Problems and Objectives to be Solved by the Invention] However, in the prior art described above, the method shown in FIG. And the 7th issue solved it.
Even in the method shown in Figure (B), the image is displayed on a cathode ray tube, so the light from the fluorescent part of the cathode ray tube is scattered and the amount of light entering the administration lens is small, making it impossible to obtain a bright image on the screen. has.

Of course, it is possible to use a bright projection lens with a large aperture ratio, but this has the problem of increasing the outer diameter of the projection lens, resulting in increased weight and cost.

The present invention is intended to solve these problems, and its purpose is to provide a projection type color display device that can provide a bright and bright projected image even with a dark projection lens having a small aperture ratio. .

[Means to solve the problem]

The projection type color display device of the present invention uses a Koehler illumination device and a color filter to display red, green, and
It is composed of a means for obtaining the three primary colors of blue light, a means for displaying an image using a liquid crystal panel with thin film transistors integrated in a matrix, a means for color synthesis using a dichroic mirror, and a means for enlarging and projecting the image. Features 0 [Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of a projection type color display unit, and a cabinet 10 has an air inlet 1 that takes in air to cool the light source.
1, an operating section 12 equipped with terminals and operating switches for connection with external equipment, and a projection lens 20 are attached.

FIG. 2 is a front sectional view of the projection color display device, and FIG. 3 is a side sectional view of the projection color display device, showing the internal structure of the projection color display device.

There are three light source casings 21, and all the light source casings 21 have the same internal configuration.

The light source housing 21 reflects the halogen lamp 22 and the light rays directed to the rear of the halogen lamp 22 forward.
The light emitted from the light source No. 3 is condensed by two lenses, a condenser lens A24 and a condenser lens B260. The heat absorption filter 25 absorbs infrared rays of light and prevents heat rays from being emitted.

The color filter 27 obtains the three primary colors of light from the white light of the halogen lamp 22, and a red color filter 27R, a green color filter 27G, and a 91-color color filter 27B are fixed to the light output portion of the light source housing 21, respectively.

Images are displayed on each liquid crystal panel 28 using primary color signals from a TV screen corresponding to the three primary colors of light, images of each color are combined by a dichroic prism 29, and projected onto a screen by a projection lens 20. .

The dichroic prism 29 is made by pasting four thin films that reflect only light in a certain wavelength range on the sides of the prism at right angles, and has the same function as a dichroic mirror.

In order to prevent the temperature inside the light source housing 21 from rising due to the heat generated by the halogen lamp 22, the sirocco fan 30 directs the warm air inside the light source housing 21 to the sirocco fan 30 through a warm air exhaust port 33 and a warm air guide path 32. The liquid is sucked into the air and discharged through the exhaust port 34 to the rear of the projection type color display device.

The circuit board 31 is mounted with an interface circuit for external equipment, a signal processing circuit, a driving circuit for a liquid crystal spring, and the like.

FIG. 4 is an optical path diagram that explains the optical path of light generated by the halogen lamp 22 until an image is displayed on the screen.

The halogen lamp 22 is placed near the focal point of the condensing lens A24, and forms a light source together with the reflector 23.

The focusing distance of the focusing lens A24 is determined by using a lens with a short focal length in order to increase the solid angle with the halogen lamp 22 and improving the light collecting efficiency. The filament image of the halogen lamp 22 is focused inside or near the projection lens 20, so it becomes diverging light on the screen, and the 1!4! lf
Reduce unevenness.

The above lighting method is the Koehler method.

The liquid crystal spring /l/28 is located slightly outside the focal length of the projection lens 20, and by varying the position of the projection lens 20, the magnification of the projected image can be varied.

Since the image displayed on the liquid crystal spring/1/2B is illuminated by a Koehler type illumination device, the amount of light transmitted through the liquid crystal spring ~28 is controlled and enters the projection lens 20 efficiently. Even with a small and expensive projection lens 28, a bright and bright projected image can be obtained.

The bonded surfaces of the dichroic prism 29, which is made by bonding four frisms together, include a positive reflection surface 45 formed with a thin film layer that reflects only light colored light, and a red reflective surface 45 formed with a thin film layer M that reflects only red light. There is a reflective surface 46, and the image of the liquid crystal panel 28 that displays a blue image is reflected by the reflective surface 45, the red image is similarly reflected by the red reflective surface 46, and the green image is transmitted through the dichroic prism 29 and projected. lens 20
The composite image is then projected.

FIG. 5 is a sectional view showing the structure of the liquid crystal spring, and FIG. 6 is an equivalent circuit diagram of the liquid crystal spring P, which briefly explains the liquid crystal panel.

The quartz substrate 50 has a transparent pixel electrode 54 in the shape of an IJ box.
is formed, and one or two thin film transistors 53 are connected to the pixel electrode 54.

The gate line 51 is connected to the gate of the thin film transistor 55 and selects one row of the thin film transistors 53 in a matrix.

The source line 52 is connected to the source of the #film transistor 55 and writes an amount of electricity corresponding to the image signal into a capacitor formed by the pixel electrode 54 and the counter electrode 56 via the thin film transistor 53.

A transparent counter electrode 56 is formed on the glass substrate 55, and @
The general optical layer 5 is opaque except for the opening 59 which is similar to the ii [
Expanded in 8. Normally, if the illumination light enters from the glass substrate 55 side and exits from the quartz substrate 50 side, the influence of light on the thin film transistor 53 can be suppressed. 6o is a polarizing plate.

By arranging the thin film transistor 53 as an active element for each pixel, when the thin film transistor 53 turns on display data, the pixel electrode 54 and the counter electrode 56
When the thin film transistor 53 writes into the capacitance formed by (S),
When FF is on, the display data is in the form of a telegraph and the capacity is 0.
Since it is Mbt and has a memory function, it is possible to display an excellent contrast characteristic.

〔Effect of the invention〕

As described above, according to the present invention, the light efficiency is improved by using Koehler type illumination, and even with a dark projection lens, the image is bright and bright, and even the edges of the screen can be illuminated without unevenness. can get.

Further, by using a liquid crystal spring/distributor in which thin film transistors are integrated in a matrix, a body with excellent contrast characteristics can be obtained.

Furthermore, since color synthesis is performed using a dichroic prism, it is possible to obtain a good image without color distortion, even to the edges of the screen.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a projection type color display device. FIG. 2 is a front sectional view of the projection type color display device. FIG. 3 is a side sectional view of the projection type color display device. Figure 4 is an optical path diagram. FIG. 5 is a sectional view showing the structure of a liquid crystal panel. Figure 6 is an equivalent circuit diagram of a liquid crystal panel. Figure 7 (a) and (b) are conventional examples. that's all Applicant: Seiko Epson Corporation Figure 1 ,”r2 diagram Figure 3 Bustle A Trap l Figure 5

Claims (1)

[Claims] A means for obtaining the three primary colors of red, green, and blue light using a Koehler illumination device and a color filter, a means for displaying an image using a liquid crystal panel integrated in a matrix of thin film transistors, a means for color synthesis using a dichroic mirror, 1. A projection type color display device comprising means for enlarging and projecting.