KR100686025B1 - reflective type Liquid Crystal Display projection system - Google Patents

Abstract

The present invention relates to a reflective LCD optical system using the polarization separation characteristics of the PBS, to provide a reflective LCD optical system for further increasing the brightness while maintaining the contrast (gradation). The present invention is a light system having a solid angle emitted from a light source and asymmetrically emitting F / # of the vertical and horizontal axes of light having an area or volume, and asymmetrical light emitted from the illumination system is separated into color and synthesized on the screen. It consists of a projection system that forms an image.

PBS, F / #, Illumination system, Gradation

Description

Reflective LCD Optical System {reflective type Liquid Crystal Display projection system}

1 is a view showing a PBS structure used in a general reflective LCD optical system

2 is a view showing that light leaks along the axis of a light source in PBS used in a general reflective LCD optical system;

FIG. 3 is a graph illustrating a content rate of P waves leaked in light transmitted when S waves are input in FIG. 2; FIG.

4 is a first embodiment showing a reflective LCD optical system according to the present invention;

FIG. 5 is a view showing entrance and exit surfaces of the optical funnel used in FIG. 4; FIG.

6 is a second embodiment showing a reflective LCD optical system according to the present invention;

7 is a view showing the structure of the light emitted from the stop portion used in FIG.

8 is a third embodiment showing a reflective LCD optical system according to the present invention;

9 is a view showing the structure of the light emitted from the stop portion used in FIG.

10 is a graph illustrating brightness and gray scale characteristics when an illumination system having an asymmetric F / # according to the present invention is applied.

* Explanation of symbols for main parts of the drawings

100: lighting system 100a: light source

110: light source lamp 120: reflective surface

130a: optical funnel 130b: integrator

140: condensing lens 150: stop portion

160: FEL 160a, 160b: lens array

200: projection system 200a: color separation / synthesis unit

200b: projection lens system 210: color selection polarizer

220: dichroic filter 230: LCD panel

The present invention relates to an optical system applied to a projection TV or monitor, and more particularly, to a reflective LCD optical system having an illumination system capable of increasing contrast and lighting efficiency.

Micro display devices, which are optical systems applied to existing projection TVs or monitors, are largely divided into reflective elements and transmissive elements. Reflective elements include reflective LCDs, LCoS and DMD, and transmissive elements include LCD.

Such micro display devices are further divided into using polarized light and non-polarized light.

Among them, the reflective LCD expresses image information by modulating the phase of polarized light. The reflective LCD has the same input and output paths.

Due to this feature, the reflective LCD uses a polarization splitting element called PBS to convert the light source having irregular polarization direction emitted from the light source lamp into a polarized light beam having a polarization direction for each type that matches the input and output paths. PBS is as shown in FIG.

As shown in FIG. 1, the PBS 10 has a PBS coating 11 between two prisms, and the S wave reflects and the P wave transmits. At this time, according to the PBS separation coating 11, S wave may be transmitted, P wave may be reflected. In the present specification, in order to facilitate the description, the S wave is reflected and the P wave is defined as using a PBS separation coating having a property of transmitting.

However, even if the PBS separation coated surface 11 has 100% of the ability to separate the P wave and S wave, as shown in FIG. This is caused by the difference between the normal of the incident light and the normal of the polarization separation plane.

That is, the characteristic of the incident light does not exist as a point light source and is formed with a solid angle. Therefore, all light sources are formed with an area or a volume. At this time, when considering the x-axis and y-axis separated from the normal of the light source as shown in Figure 2, the light source corresponding to the y-axis 100% reflection in the PBS separation coating 11, but corresponds to the x-axis The light source is leaked from the PBS separation coating 11 to be partially transmitted. In the figure, the portion indicated by the dotted line shows the light transmitted through leakage.

The leakage amount is defined by the following equation (1) by the angle of incidence inside the material.

The amount of leakage according to the angle inside the material according to Equation 1 is reflected and leaked as the angle increases, as shown in a graph showing the content of P waves in the light transmitted from the PBS separation coating when S wave is input in FIG. 3. It can be seen that the content of P waves that are not increased is increased.

For this reason, even when designing the illumination system of a reflective LCD system using PBS with perfect performance, the contrast is degraded.

Accordingly, an object of the present invention is to provide a brighter system while maintaining contrast using polarization separation characteristics of PBS.

It is another object of the present invention to construct an illumination system using an optical element that can have an asymmetric F / # like an optical funnel in a reflective LCD illumination system, and to implement a brighter system having a high gray level using the optical system. .

Still another object of the present invention is to implement a high gradation and bright illumination system using a light tunnel or FEL (Fly Eye Lens) and a specially shaped aperture or FEL and aperture in the new type illumination system.

Reflective LCD optical system according to the present invention for achieving the above object is a light source unit for emitting light, a light uniform unit for emitting by adjusting the uniformity of the emitted light, the light amount of the light emitted from the light uniforming unit to adjust the vertical axis And a stop unit for increasing the length of any one of the horizontal axis and the horizontal axis, and a projection system for forming an image on a screen by separating and synthesizing the light emitted from the stop part.
In addition, the reflective LCD optical system according to the present invention is a light source unit for emitting light, a light uniform portion having a structure larger than the surface to be emitted by adjusting the uniformity of the light emitted from the surface receiving the light emitted from the light source, the light uniform portion And a projection unit for adjusting the amount of light emitted from the light beam and lengthening one of the vertical axis and the horizontal axis to make the length longer, and a projection system for separating and synthesizing the light emitted from the stop part to form an image on a screen. It is done.
Here, the light uniform part is any one selected from a light funnel, a light tunnel, and a fly eye lens (FEL).
In addition, the reflective LCD optical system according to the present invention includes a light source unit including a light source lamp for emitting light and a reflecting surface for adjusting the emission direction of the emitted light, a first splitting the light emitted from the light source unit into a plurality of partial luminous fluxes; A FEL composed of a two-lens array, a stop portion which is positioned on a second lens array of the FEL, adjusts the amount of light emitted from the light source unit, and lengthens one of the vertical axis and the horizontal axis to be longer; And a projection system for separating and synthesizing light to form an image on a screen.

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As seen above, light leakage does not occur on one axis (y-axis) in PBS, but light leakage occurs depending on the angle on the other axis (x-axis).

Using this phenomenon, when designing an illumination system in a PBS-based system, the F / # s of the vertical axis (y axis) and the horizontal axis (x axis) are designed differently (asymmetric F / #) for the plane of separation of the PBS. Increasing the brightness while minimizing the contrast, minimizing the decrease in brightness and improving the gradation.
Here, F / # represents the angle of the illumination light, and as the F / # is smaller, the angle of the illumination light becomes larger, and thus, much light can be received when the illumination angle is increased.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments with reference to the accompanying drawings.

A preferred embodiment of the reflective LCD optical system according to the present invention will be described with reference to the accompanying drawings.

First embodiment

4 is a first embodiment showing a reflective LCD optical system according to the present invention.

As shown in FIG. 4, the reflective LCD optical system has an illumination system 100 that emits light in which the F / # s of the vertical axis and the horizontal axis are differently formed, and color-separates and synthesizes the light emitted from the illumination system 100 to form an image on a screen. It consists of the projection system 200.

In this case, the illumination system 100 includes a light source unit 100a that includes a light source lamp 110 that emits light and a reflective surface 120 that adjusts an emission direction of the emitted light, and light emitted from the light source unit 100a. To adjust the uniformity of the, and as shown in Fig. 4 (a) to make the x-axis longer than the y-axis optical funnel (funnel to emit asymmetrically F / # about the vertical and horizontal axis of the light emitted from the light source (100a) 130a, a condensing lens 140 that is incident and superimposed so that light uniformly input from the optical funnel 130a with asymmetry is perpendicular to the incidence plane, and is emitted from the condensing lens 140 It is composed of a stop (150) (150) for adjusting the light amount of the light through the aperture.

In this case, as shown in FIG. 5, the optical funnel 130a is preferably formed to be larger than the surface from which the light input from the light source unit 100a receives the light, and instead of the optical funnel 130a. You can use either optical tunnels or FEL (Fly Eye Lens) and specially shaped apertures or FELs and apertures.

The projection system 200 is combined with the color selection polarizer 210, the dichroic filter 220, and the LCD panel 230 to change the path of the light emitted from the illumination system 100 and form an image for each color. And a color separation / synthesis unit 200a for synthesizing each image thus formed into one image, and an image synthesized by the color separation / composition unit 200a through a large imager to form an image on a screen. It consists of a lens system 200b.

In this way, by changing the shape of the optical funnel 130a of the illumination system 100, the F / # for the vertical axis (y axis) and the horizontal axis (x axis) in the illumination system can be emitted differently (asymmetric F / #) to the optical system. Will be. That is, the asymmetric light of F / # is emitted to the optical system in an elongated form in which the upper and lower portions of the light incident in the direction of the axis perpendicular to the incident polarizer are blocked.

Accordingly, the image formed on the screen can increase the brightness while maintaining the contrast.

Second embodiment

6 is a second embodiment showing a reflective LCD optical system according to the present invention.

As shown in FIG. 6, the projection display apparatus includes an illumination system 100 that emits light having a different F / # on the vertical axis and a horizontal axis, and a projection that forms images on a screen by separating and synthesizing the light emitted from the illumination system 100. It can be divided into the system 200.

In this case, the illumination system 100 includes a light source unit 100a that includes a light source lamp 110 that emits light and a reflective surface 120 that adjusts an emission direction of the emitted light, and light emitted from the light source unit 100a. An integrator 130b that adjusts the uniformity of the condenser, a condensing lens 140 that is incident and superimposed so that light uniformly emitted from the integrator 130b is perpendicular to the incident surface, and the condensing lens 140 As shown in FIG. 7, the y-axis light source is partially blocked through the iris, and the stop unit 150 asymmetrically adjusts F / # for the vertical axis and the horizontal axis.

In this case, the integrator 130b may use any one of an optical funnel, an optical tunnel, and a fly eye lens (FEL).

The projection system 200 is combined with the color selection polarizer 210, the dichroic filter 220, and the LCD panel 230 to change the path of the light emitted from the illumination system 100 and form an image for each color. And a color separation / synthesis unit 200a for synthesizing each image thus formed into one image, and an image synthesized by the color separation / composition unit 200a through a large imager to form an image on a screen. It consists of a lens system 200b.

Accordingly, the F / # is designed differently (asymmetric F / #) with respect to the vertical axis (y axis) and the horizontal axis (x axis) in the illumination system 100 to be emitted to the optical system 200. That is, the asymmetric light of F / # is emitted to the optical system in an elongated form by blocking the upper and lower portions of the light incident in the direction of the axis perpendicular to the incident polarizing plate through the aperture.

Accordingly, the image formed on the screen can increase the brightness while maintaining the contrast.

Third embodiment

8 is a third embodiment showing a reflective LCD optical system according to the present invention.

As shown in FIG. 8, the projection display apparatus includes an illumination system 100 that emits light having differently formed F / # s on a vertical axis and a horizontal axis, and a projection that forms images on a screen by separating and synthesizing the light emitted from the illumination system 100. It can be divided into the system 200.

In this case, the illumination system 100 includes a light source unit 100a including a light source lamp 108 that emits light and a reflecting surface 120 that adjusts an emission direction of the emitted light, and light emitted from the light source unit 100a. The FEL 160 including the first and second lens arrays 160a and 160b for dividing the light into a plurality of partial light beams, and the light emitted from the FEL 160 through a y-axis light source as shown in FIG. A part of the stop 150 that asymmetrically adjusts F / # with respect to the vertical axis and the horizontal axis and the partial light beams emitted from the stop part 150 are incident and overlapped so as to be perpendicular to the incident plane. Condensing lens 140 is emitted.

The projection system 200 is combined with the color selection polarizer 210, the dichroic filter 220, and the LCD panel 230 to change the path of the light emitted from the illumination system 100 and to generate a color-specific image. A color separation / synthesis unit 200a for forming and synthesizing each image thus formed into one image, and an image synthesized in the color separation / composition unit 200a is enlarged through the imager to form an image on a screen. It consists of the projection lens system 200b.

Accordingly, the F / # is designed differently (asymmetric F / #) with respect to the vertical axis (y axis) and the horizontal axis (x axis) in the illumination system 100, and is emitted to the optical system. That is, the asymmetric light of F / # is emitted to the optical system 200 in an elongated form by blocking the upper and lower portions of the light incident in the direction of the axis perpendicular to the incident polarizing plate through the aperture.

Accordingly, the image formed on the screen can increase the brightness while maintaining the contrast.

When the illumination system having an asymmetric F / # is applied by blocking the upper and lower portions of the light incident in the direction of the axis perpendicular to the incident polarizer, the brightness and the gray characteristics are the same gray level as shown in the graph of FIG. 10. You can increase the brightness even more while maintaining it.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

As described above, the reflective LCD optical system according to the present invention uses a light funnel, a light tunnel, a FEL, and a stop to form an illumination system having an asymmetrical F / #, thereby providing a conventional symmetrical F /. The performance can be further improved than the illumination system having #.

Claims (7)

A light source unit emitting light; A light uniform part which emits light by adjusting the uniformity of the emitted light; A stop unit which controls the amount of light emitted from the light uniform part and lengthens the length of any one of a vertical axis and a horizontal axis; And a projection system for forming an image on a screen by separating and synthesizing the light emitted from the stop part. A light source unit emitting light; A light uniform part having a structure in which a surface receiving the light emitted from the light source unit is larger than a surface emitted by adjusting the uniformity of the emitted light; A stop unit configured to adjust an amount of light emitted from the light uniform part and to lengthen one of the vertical axis and the horizontal axis; And a projection system for forming an image on a screen by separating and synthesizing the light emitted from the stop part. delete delete The light uniforming part of claim 1 or 2, Reflective LCD optical system, characterized in that any one selected from a funnel, light tunnel (tunnel) and FEL (Fly Eye Lens). A light source unit including a light source lamp for emitting light and a reflective surface for adjusting an emission direction of the emitted light; A FEL comprising first and second lens arrays for dividing the light emitted from the light source into a plurality of partial luminous fluxes; A stop unit positioned on the second lens array of the FEL and configured to adjust an amount of light emitted from the light source unit and to lengthen one of the vertical axis and the horizontal axis; And a projection system for forming an image on a screen by separating and synthesizing the light emitted from the stop part. delete

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