KR960016281B1 - Projection type image display apparatus - Google Patents

Abstract

the first and the second light source(10,10') emitting white light having high intensity; an optical beam-separating means(20) separating the light into red, green or blue color beams in sequence by receiving the optical beam emitted from the first and the second light source; the first and the second beam intensity-regulating means(30,30') regulating the beam intensity as to the separated optical beams; a projection lens(40) projecting the optical beams on a screen; and a screen(50) displaying an image in response to the projection lens.

Description

Projection type image display device

1 is a schematic diagram of a projection image display apparatus of the present invention.

2A is a diagram showing a screen for a conventional projection image display device, and (B) is a diagram showing a screen for a projection image display device of the present invention.

* Explanation of symbols for main parts of the drawings

10,10 ': light source 20: optical separation

30,30 ': first and second light amount adjusting unit 40: projection lens

50: screen

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type image display apparatus, and more particularly, to a projection type image display apparatus configured to provide a clear screen by configuring two light sources to improve light efficiency and to improve a difference in light quantity between the center and the periphery of the screen.

An image display apparatus is classified into a direct view type image display apparatus and a projection type image display apparatus according to a display method. The direct view type image display apparatus includes a cathode ray tube (Cathode Ray Tube; hereinafter referred to as CRT), and such a CRT). Such a CRT image display apparatus has a relatively good image quality, but the weight and thickness are increased as the screen is enlarged. There is a problem that the increase of the price and the price is expensive, there is a limit to implement the large screen.

Projection type image display apparatuses include a large crystal display (Liquid Crystal Display; hereinafter referred to as LCD), and such a large-screen LCD can be thinned to reduce its weight. However, such LCDs have a high loss of light due to the polarizing plate, and thin film transistors for driving the LCD are formed for each pixel, so that there is a limit in increasing the aperture ratio (light transmission area).

Therefore, a projection type image display apparatus using Actuated Mirror Arrays (hereinafter referred to as AMA) has been developed by Aura, United States of America as a light quantity adjusting element.

The AMA is distinguished from using a one-dimensional AMA and using a two-dimensional AMA. The one-dimensional AMA has mirror surfaces arranged in an M × 1 array, and the two-dimensional AMA has mirror surfaces arranged in an M × N array. Therefore, a projection image display device using a one-dimensional AMA pre-scans M × 1 beams using a scanning mirror, and a projection image display device using a two-dimensional AMA projects M × N beams to produce an array of M × N pixels. Branches represent images.

A general projection type image display device is constructed by projecting one screen with one light source and one light quantity adjusting means. However, the number of pixels suitable for high-definition television (HDTV) or movie projection, that is, the pixel count, which is much higher than that for general television, must be processed for each pixel within a limited area. The size becomes smaller and therefore the pixel processing becomes more difficult.

In addition, there is a problem of light efficiency in which the light effective area corresponding to each pixel, that is, the actual area of light transmitted or reflected in the entire area, is reduced. Also, since the center of the screen is very bright compared to the periphery, the peripheral water screen is not clear There is this.

Accordingly, the present invention improves the reduction in light efficiency that accompanies the increase in the number of pixels in producing high definition television or movie projection, and the amount of light in the center and periphery, which is one of the important problems in projection using a light source. It is an object of the present invention to provide a projection type image display device which reduces the difference and realizes a clear screen.

According to the present invention, a projection image display apparatus includes: first and second light sources for emitting white light having high brightness; Optical separation means for sequentially separating red, green, or blue light by incident light beams emitted from the first and second light sources; First and second light amount adjusting means for adjusting the light amount with respect to the light beams separated by the light separating means; A projection lens for projecting light beams on a screen in response to the first and second light amount adjusting means; And a screen for implementing an image in response to the projection lens.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail as follows.

FIG. 1 is a schematic view of a projection type image display apparatus according to an embodiment of the present invention. Referring to FIG. 1, preferred embodiments of the present invention include first and second light sources 10 and 10 ', and an optical separation unit 20. FIG. ), The first and second light amount adjusting units 30 and 30 ', the projection lens 40, and the screen 50.

The first and second light sources 10 and 10 ′ emit white light of high intensity, respectively. The light splitter 20 is composed of rotating color wheels or dichroic mirrors and emits red, green, or blue beams of white light emitted from the first and second light sources 10 and 10 '. In addition, the color wheel in the light separation unit 20 is separated so that the color filters for transmitting any one of the red, green or blue luminous flux (color filters) have the same area, and the image signal Rotate an integer multiple of a field or frame.

The first and second light amount adjusting units 30 and 30 'are made of a reflective panel having one or more slits, and transmit the light beams passing through the light splitting unit 20 to the projection lens 40. To reflect. As described above, the projection lens 40 passes through the gaps of the first and second light amount adjusting units 30 and 30 ', and enters the light beams whose light amount is adjusted to project the screen 80 on the screen 80 to implement a desired image. do. Finally, the screen 50 is projected in the form of a combination of two screens on one screen through the two light sources 30, 30 'and the two light intensity control units 30, 30' described above to produce a desired image. Implement

Referring now to Figures 1 and 2, a series of operations and effects of the preferred embodiments of the present invention will be described in detail.

The first and second light sources 10 and 10 'emit white light of high brightness, and in a conventional projection type image display apparatus, it is common to use a single light source. The screen in the case of using a single light source is as shown in FIG. In other words, in the rectangular form of light on a 4 × 3 screen or 16 × 9 screen of an HDSC system, light loss occurs in the rectangular shape, indicating that a large amount of light is projected to the center and a smaller amount of light is projected to the periphery. Therefore, in the present invention, as shown in FIG. 2 (b), white light is emitted by two light sources to make the difference in the amount of light almost uniform, thereby realizing a good image.

On the other hand, when moving and projecting the 16 × 9 screen of the HDTV by moving and dividing the first light source and the second light source, the light loss can be reduced to a square shape by projecting similarly to the circle, which is the shape of the 8 × 9 light source, respectively. The light emitted from the first and second light sources 10 and 10 ′ is incident on the light separation unit 20 to sequentially separate red, green, or blue light beams through a color wheel or a color-selective reflector. In addition, such a color wheel rotates at an integral multiple of the field or frame of the image signal and irradiates the first and second light amount adjusting units 30 and 30 '.

The first and second light amount adjusting units 30 and 30 ′ enter the light beam irradiated from the light splitting unit 20 to control the light amount through one or more gaps, and transmit the light beams passing through the gaps to the projection lens 70. Projection onto the front screen 50 to achieve a desired image. This projection is composed of the light beams passing through the first light amount adjusting unit 30 and the projection lens 40 on the hinge side 51 in the screen 50, while the second light amount adjusting unit 30 'and the projection lens ( The light beams passing through 40 are projected onto the other side 52 in the screen 50 to implement one screen, thereby reducing the difference in light quantity between the center and the periphery of the screen, thereby providing a clear screen.

As described above, the present invention includes the first and second light sources 10 and 10 'and the first and second light amount control units 30 and 30' to reduce the decrease in light efficiency due to the increase in the number of pixels. In addition, there is an effect of realizing a clear screen by reducing the light difference between the center and the periphery of the screen.

Claims (2)

A projection image display device comprising: first and second light sources (10) (10 ') for emitting white light of high brightness; Optical separation means (20) for sequentially separating red, green, or blue light by incident light beams emitted from the first and second light sources (10, 10 '); First and second light amount adjusting means (30) (30 ') for adjusting the amount of light with respect to the light beams separated by the light separating means (20); A projection lens (40) for projecting luminous fluxes on the screen in response to the first and second light amount adjusting means (30, 30 '); And a screen (50) for realizing an image in response to the projection lens (40). According to claim 1, The screen 50, the luminous flux through the first light beam 10 and the first light amount adjusting means 30 is projected on one side 51 of the screen 50, the second The light beam through the light source 10 'and the second light amount adjusting means 30' is projected onto the other side 52 of the screen 50 to form one screen.