KR100698752B1 - Optical system of projection display - Google Patents

Abstract

The present invention relates to an optical system of a projection display, comprising: an apparatus for time-dividing light of a white light source into light of first and second wavelengths or light of third and fourth wavelengths and emitting time-divided light; A first optical component which reflects light of the first and third wavelengths and transmits the light of the second and fourth wavelengths among the time-divided and emitted light from the apparatus; A second optical part for transmitting only light in a specific polarization direction among the light of the second and fourth wavelengths transmitted from the first optical part; A third optical part for transmitting only light in a specific polarization direction among the first and third wavelengths of light reflected by the first optical part; A first panel which receives light having a wavelength reflected from the second optical component and modulates the light according to a gray level of image information; And a second panel configured to receive light having a specific wavelength transmitted from the third optical component and modulate the light according to the gray level of the image information.

Therefore, the present invention implements the optical system using the red, green, blue, and yellow sub-colors, thereby extending the color expression area and increasing the amount of light.

Optical system, micro, display, polarization, reflection, transmission, emission

Description

Optical system of projection display

1 is a block diagram of a typical single plate optical system

2A and 2B are schematic diagrams of an optical system of a projection display according to the present invention.

3 is a block diagram of an embodiment of an illumination unit used in the optical system according to the present invention

4A and 4B are conceptual views for explaining the function of the color divider used in the lighting unit according to the present invention.

5 is a graph of spectral transmittance of magenta light in an optical system according to the present invention.

6 is a spectral transmittance graph of light transmitted through a dichro mirror in an optical system according to the present invention;

7 is a spectral transmittance graph of light reflected from a dichro mirror in an optical system according to the present invention;

8 is a graph of spectral transmittance of yellowish light in the optical system according to the present invention.

9 is another spectral transmittance graph of light transmitted through a dichro mirror in the optical system according to the present invention

10 is another spectral transmittance graph of light reflected by a dichro mirror in an optical system according to the present invention;

FIG. 11 is a graph illustrating chromaticity coordinates of the CIE (Commissiom International on Illumination) of the temple color optical system and the conventional three primary color optical system according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: lighting unit 110: lamp

120: integrator 130: color division

131: color wheel 131a, 131b: color filter

200: dichroic mirror 300,500: polarized beam splitter

400,600: Micro Display 700: Projection Lens

800: screen

The present invention relates to an optical system of a projection display, and more particularly, to a projection display that can extend the color expression area and increase the amount of light by implementing the optical system using the red, green, blue, and yellow color of the temple. It relates to an optical system.

In recent years, as satellite and digital broadcasting are promoted in earnest, demand and interest for large-screen displays having high resolution have increased, and expectations and roles for projection and projectors have become very important.

In addition, as the demand for high brightness and high definition image information has become stronger, research on high optical efficiency and inexpensive optical system is being conducted in various ways.

In recent years, display devices have tended to become lighter, lighter, and larger, and in particular, projection display devices have become an important issue.

In order to achieve such a light weight and light weight, there is a need for an optical system that reduces the number of micro displays instead of using three micro displays in a projection display.

Such optical systems include two-plate optical systems using two micro displays and single-plate optical systems using one micro display.

1 is a configuration diagram of a general single plate optical system, wherein the single plate optical system includes a lamp 1, an integrator 2, a color wheel 3, an illumination lens 4, It consists of a polarizing beam splitter (PBS) or a total internal reflection (TIR) prism 5 and a panel 6.

In this single plate optical system, the light emitted from the lamp 1 becomes a light having a uniform spatial distribution while passing through the integrator 2, and the light passing through the integrator 2 is red in the color wheel 3. The color is divided into three colors in time by three color filters of red, green, and blue.

This split light passes through the illumination lens 4 and passes through the PBS or TIR prism 5 to the micro display 6.

Such a single plate optical system is inexpensive and simple in structure as compared to a two plate optical system, but has a problem that the amount of light is significantly smaller.

On the other hand, the three-plate optical system has a limitation in improving the image quality due to the complicated structure, high production cost, and narrow color gamut.

In order to solve the problems described above, the present invention implements an optical system using red, green, blue, and yellow sub-colors to extend the color expression area and increase the amount of light. The purpose is to provide.

A first preferred aspect for achieving the above objects of the present invention comprises a white light source, time-dividing the light of the white light source into light of the first and second wavelengths or the third and fourth wavelengths, An illumination unit for polarizing and time-dividing the light;

A dichroic mirror that receives light of the first and second wavelengths or the light of the third and fourth wavelengths emitted from the illumination unit, reflects the light of the first and third wavelengths, and transmits the light of the second and fourth wavelengths;

A first polarization beam splitter (PBS) which receives light of the second and fourth wavelengths transmitted from the dichroic mirror and transmits only light in a specific polarization direction;

A second polarization beam splitter which receives light of the first and third wavelengths reflected from the dichroic mirror and transmits only light in a specific polarization direction;

First and second micro displays that receive light of first and third wavelengths and light of second and fourth wavelengths transmitted from the first and second polarizing beam splitters, respectively, and modulate the light according to gray levels of image information;

There is provided an optical system of a projection display including a projection lens for enlarged projection of light modulated and output from the first and second micro displays on a screen.

A second preferred aspect for achieving the above objects of the present invention is to time-divide the light of a white light source into light of the first and second wavelengths or light of the third and fourth wavelengths, and to emit the time-divided light. An apparatus;

A first optical component which reflects light of the first and third wavelengths and transmits the light of the second and fourth wavelengths among the time-divided and emitted light from the apparatus;

A second optical part for transmitting only light in a specific polarization direction among the light of the second and fourth wavelengths transmitted from the first optical part;

A third optical part for transmitting only light in a specific polarization direction among the first and third wavelengths of light reflected by the first optical part;

A first panel which receives light having a wavelength reflected from the second optical component and modulates the light according to a gray level of image information;

Provided is an optical system of a projection display including a second panel that receives light of a specific wavelength transmitted from the third optical component and modulates and outputs the light according to a gray level of image information.

According to a third aspect of the present invention, there is provided a light emitted from a light source as a pair of light in which two colors selected from the first to fourth color sub-components are respectively synthesized. An illumination unit configured to time-division and emit the light;

A dividing device for dividing and outputting a pair of light, each of which is divided into two colors time-divided by the lighting unit, into light of first to fourth colors;

A projection display including first and second panels that receive two of the light of the first to fourth colors divided by the splitter and two remaining lights, respectively, and modulate the output according to the gray level of the image information; An optical system of is provided.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

2A and 2B are structural diagrams of an optical system of a projection display according to the present invention, including a white light source, time-dividing and time-dividing the light of the white light source into light of the first and second wavelengths or the third and fourth wavelengths. An illumination unit 100 for polarizing and emitting light; The dichroic light receiving the first and second wavelengths or the third and fourth wavelengths emitted from the illumination unit 100 reflects the light of the first and third wavelengths and transmits the light of the second and fourth wavelengths. A mirror 200; A first polarization beam splitter (PBS) 300 which receives light of the second and fourth wavelengths transmitted from the dichroic mirror 200 and transmits only light in a specific polarization direction; A second polarization beam splitter 500 which receives light of the first and third wavelengths reflected by the dichroic mirror 200 and transmits only light in a specific polarization direction; First and second micros which receive the light having the first and third wavelengths and the light having the second and fourth wavelengths transmitted from the first and second polarizing beam splitters 300 and 500, respectively, and modulate the light according to the gray level of the image information. Displays 400 and 600; And a projection lens 700 for projecting the light modulated and output from the first and second micro displays 400 and 600 onto the screen 800.

Herein, a dichroic prism that transmits light of first and third wavelengths and reflects light of second and fourth wavelengths among the light modulated and output from the first and second micro displays 400 and 600 ( It is preferable that 700) is further provided.

The first and second polarization beam splitters 300 and 500 transmit only light of a P wave or a S wave.

In addition, the light of the first and second wavelengths is magenta light in which red light and blue light are synthesized, and the light of the third and fourth wavelengths is yellow light and green light. (Green) Light is composed of synthesized Yellowish light.

In addition, the first and second micro displays 400 and 600 use a liquid crystal on silicon (LCoS) panel, which is a reflective LCD.

Meanwhile, the dichroic mirror 200 and the first and second polarization beam splitters 300 and 500 may emit a pair of light in which two colors, which are time-divided and output from the illumination unit, are respectively synthesized. It becomes a component of the splitter which splits and emits each light.

Therefore, referring to the operation of the optical system of the projection display according to the present invention, first, the light of the white light source is time-divided into the light of the first and second wavelengths or the third and fourth wavelengths in the illumination unit 100 to dichroic mirror ( When the light is incident on the dichroic mirror 200, the dichroic mirror 200 reflects light of the first and third wavelengths time-divided by the lighting unit 100 and transmits the light of the second and fourth wavelengths.

The light of the second and fourth wavelengths transmitted from the dichroic mirror 200 is incident on the first polarization beam splitter 300 to transmit only light in a specific polarization direction, and the first light is transmitted through the dichroic mirror 200. The light having the wavelength of 3 and 3 is incident on the second polarization beam splitter 500 so that only light in a specific polarization direction is transmitted.

The light of the first and third wavelengths and the light of the second and fourth wavelengths transmitted by the first and second polarization beam splitters 300 and 500 may be applied to the gray levels of the image information on the first and second microdisplays 400 and 600, respectively. The image is modulated according to the projection lens and projected on the screen 700.

In this case, the light of the first and second wavelengths is a magenta light in which red light and blue light are synthesized, and the light of the third and fourth wavelengths is yellow light and green ( In the case where the yellow light is synthesized, in the optical system, FIG. 2A illustrates the path of magenta, and FIG. 2B illustrates the path of yellowish light.

First, when the path of the magenta light is described, if the light time-divided and emitted from the illumination unit, that is, the light in 'a' of FIG. 2A is magenta light in which the red light R and the blue light B are synthesized as shown in FIG. The red light is reflected and the blue light is transmitted through the lower mirror 200.

At this time, the reflected red light is transmitted to the second micro display 600 by passing only P-polarized light, that is, P-wave red light RP, in the second polarizing beam splitter 500, and in the second micro display 600. Light RS modulated according to the gray level of the image information is reflected from the dichroic prism 700 and output to the projection lens.

The projected blue light is transmitted through only the P-wave blue light BP in the first polarization beam splitter 400 and is incident on the first micro display 300, and the gray of the image information is respectively displayed on the first micro display 300. The light BS modulated according to the level is reflected by the dichroic prism 700 and output to the projection lens.

In addition, when the path of the yellowish light is described, the light time-divided and emitted from the lighting unit, that is, the light in 'd' of FIG. 2B is synthesized by the yellow light and the green light as shown in FIG. 8. In the yellowish light, the yellow light Y is reflected by the dichroic mirror 200, and the green light G is transmitted.

At this time, the reflected yellow light Y is transmitted through the second polarization beam splitter 500 to only the P-polarized light, that is, the P-wave yellow light YP, and is incident on the second micro display 600. The light RS modulated according to the gray level of the image information in the display 600 is reflected by the dichroic prism 700 and output to the projection lens.

In addition, the green light G projected by the dichroic mirror 200 is incident on the second micro display 600 by passing only the P-wave green light GP in the first polarization beam splitter 400. The light RS modulated according to the gray level of the image information in the two micro display 600 is reflected by the dichroic prism 700 and output to the projection lens.

3 is a block diagram of an embodiment of an illumination unit used in the optical system according to the present invention, and includes a lamp 110 for emitting white light; An integrator 120 for uniformizing the distribution of the white light emitted from the lamp 110; The integrator 120 includes a color dividing unit 130 for time-dividing white light uniformed by the first and second wavelengths or the light of the third and fourth wavelengths.

The lighting unit emits white light from the lamp 110, and the emitted white light is transmitted to the color splitter 130 after the light distribution is uniform in the integrator 120.

Thereafter, in the color dividing unit 130, the white light is time-divided into the light of the first and second wavelengths or the light of the third and fourth wavelengths and is emitted.

Such a configuration of the lighting unit is only one embodiment of the present invention, and can be implemented in various configurations and methods.

4A and 4B are conceptual views illustrating the function of the color divider used in the lighting unit according to the present invention. The color divider used in the lighting unit according to the present invention is a conventional color wheel as shown in FIG. 4A. 131 can be used, which is divided into a first color filter 131a that transmits yellowish light and a second color filter 131b that transmits magenta light. It is.

At this time, as shown in FIG. 4B, when the color wheel 131 is being rotated, the white light incident on the color wheel 131 passes through the first color filter 131a, and yellowish yellow light is emitted. When the color wheel 131 is further rotated as time passes, the magenta light is emitted through the second color filter 131b.

According to the above description, the color dividing part of the present invention is time-divisionally divided into yellowish light and magenta light.

FIG. 5 is a spectral transmittance graph of magenta light in an optical system according to the present invention. When time-division magenta light is emitted from an illumination unit, that is, red light R and blue light B in 'a' of FIG. 2A. ) Is measured by the synthesized spectroscopic graph.

FIG. 6 is a spectral transmittance graph of light transmitted through a dichro mirror in the optical system according to the present invention. When magenta light is incident on the dichro mirror, blue light B is transmitted.

7 is a spectral transmittance graph of light reflected from a dichro mirror in the optical system according to the present invention, and the light reflected by the magenta light incident on the dichro mirror is red light (R).

8 is a spectral transmittance graph of yellowish light in the optical system according to the present invention, in which 'd' of FIG. The spectral transmittance graph of is a spectral graph in which green light (G) and yellow light (Y) are synthesized.

FIG. 9 is another spectral transmittance graph of light transmitted through a dichro mirror in the optical system according to the present invention. When yellowish light is incident on the dichro mirror, green light G is transmitted.

10 is another spectral transmittance graph of light reflected from a dichro mirror in the optical system according to the present invention. When yellowish light is incident on the dichro mirror, the reflected light is yellow light (Y).

FIG. 11 is a graph illustrating chromaticity coordinates of the CIE (Commissiom International on Illumination) of the temple color optical system and the conventional three primary color optical system according to the present invention. Since the chromaticity coordinates of the quaternary optical system of the present invention are rectangular shapes represented by '1000', the optical system of the present invention may further implement colors as much as the 'K' region, as shown in the graph shown in FIG. Since the spectral band of the yellow region is not used in the spectral band of the present invention, the amount of light can be increased by using the spectral band of the yellow region.

As described above, the present invention implements an optical system using the red, green, blue, and yellow sub-colors, thereby expanding the color expression area and increasing the amount of light.

Although the invention has been described in detail only with respect to specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

Claims (12)

An illuminating unit including a white light source, time-dividing the light of the white light source into light of the first and second wavelengths or the third and fourth wavelengths, and polarizing and emitting the time-divided light; A dichroic mirror that receives light of the first and second wavelengths or the light of the third and fourth wavelengths emitted from the illumination unit, reflects the light of the first and third wavelengths, and transmits the light of the second and fourth wavelengths; A first polarization beam splitter (PBS) which receives light of the second and fourth wavelengths transmitted from the dichroic mirror and transmits only light in a specific polarization direction; A second polarization beam splitter which receives light of the first and third wavelengths reflected from the dichroic mirror and transmits only light in a specific polarization direction; First and second micro displays that receive light of first and third wavelengths and light of second and fourth wavelengths transmitted from the first and second polarizing beam splitters, respectively, and modulate the light according to gray levels of image information; And a projection lens to enlarge and project the light modulated and output from the first and second micro displays onto a screen. The method of claim 1, Among the light modulated and output from the first and second micro displays, a dichroic prism for transmitting the light of the first and third wavelengths and reflecting the light of the second and fourth wavelengths is further provided. Optical system of the display. The method according to claim 1 or 2, The lighting unit, A lamp for emitting white light; And a color dividing unit for time-dividing the white light emitted from the lamp into light of first and second wavelengths or light of third and fourth wavelengths. The method according to claim 1 or 2, The light of the first and second wavelengths, Red light and Red light are magenta light synthesized, The light of the third and fourth wavelengths, An optical system of a projection display, wherein the yellow light and the green light are combined with yellowish light. The method according to claim 1 or 2, The first and second micro display, An optical system of a projection display, which is a liquid crystal on silicon (LCoS) panel that is a reflective LCD. The method of claim 3, wherein And an integrator for uniformizing the distribution of the white light emitted from the lamp and outputting the same to the color dividing unit. The method of claim 3, wherein The color splitter, An optical system of a projection display, characterized in that it is a color wheel. An apparatus for time-dividing the light of the white light source into light of the first and second wavelengths or light of the third and fourth wavelengths and emitting time-divided light; A first optical component which reflects light of the first and third wavelengths and transmits the light of the second and fourth wavelengths among the time-divided and emitted light from the apparatus; A second optical part for transmitting only light in a specific polarization direction among the light of the second and fourth wavelengths transmitted from the first optical part; A third optical part for transmitting only light in a specific polarization direction among the first and third wavelengths of light reflected by the first optical part; A first panel which receives light having a wavelength reflected from the second optical component and modulates the light according to a gray level of image information; And a second panel configured to receive light having a specific wavelength transmitted from the third optical component and modulate the light according to the gray level of the image information. The method of claim 8, The light of the first and second wavelengths, Red light and Red light are magenta light synthesized, The light of the third and fourth wavelengths, An optical system of a projection display, wherein the yellow light and the green light are combined with yellowish light. The method according to claim 8 or 9, The light of the specific polarization direction, P (Primary) The optical system of the projection display, characterized in that light in the polarization direction. An illumination unit for time-dividing the light emitted from the light source into a pair of light in which two colors selected from among the first to fourth color quaternary colors are synthesized; A dividing device for dividing and outputting a pair of light, each of which is divided into two colors time-divided by the lighting unit, into light of first to fourth colors; A projection display including first and second panels that receive two of the light of the first to fourth colors divided by the splitter and two remaining lights, respectively, and modulate the output according to the gray level of the image information; Optical system. The method of claim 11, The first to fourth colors are, Optical system of the projection display, which is red, green, blue and yellow.

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