KR100344067B1 - Projection type display device using liguid crystal device - Google Patents

Abstract

The present invention relates to a projection display device using a liquid crystal display device, comprising a color separation optical system including at least two dichroic mirrors for separating light into R, G and B light between a light source and an illumination optical system. In the lower part of the PBS, R, G, and B light separated from the dichroic mirror are focused on each of the R, G, and B pixels, and the liquid crystal display device controls the same incident angle and exit angle of the R, G, and B light. Install it.

Then, since the light incident on the color separation optical system is divided into three primary colors of light and used, the light utilization efficiency can be increased as much as that of the projection display device using three liquid crystal display elements.

In addition, since one liquid crystal display element is used, the cost of the projection display device can be reduced.

Description

Projection type display device using liguid crystal device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection display device using a liquid crystal display device, and more particularly, a dike that separates light between red, green, and blue (hereinafter, R, G, and B) light between a light source and an illumination optical system. Projection type display that improves the utilization efficiency of light by installing at least two dichroic mirrors and improving the structure of the liquid crystal display device so that the incident angle and the exit angle of R, G, and B light incident on the liquid crystal display device are the same. Relates to a device.

Recently, since consumers prefer a large display device having a small thickness and a large screen display effective area, development of a projection display device using a liquid crystal display device has been continuously performed to satisfy this problem.

Projection type display device has a small sized liquid crystal display inside the housing, and installs an illumination optical system for emitting and guiding light at the rear of the liquid crystal display, and enlarges the image signal transmitted from the liquid crystal display at the front of the liquid crystal display. To install the projection lens to the screen. Projection type display devices having such a structure are thinner than the CRTs of the same size and can be easily enlarged.

One or three liquid crystal display devices may be built in the projection display device. There is a big difference in performance and price of the projection display device according to the number of liquid crystal display devices.

A projection display device in which one liquid crystal display device is built will be described as follows.

The light is emitted from the lamp, and the color separation wheel, which is installed at the front of the lamp and rotates at a high speed by a motor, selectively separates the wavelength of the predetermined color from the light emitted from the lamp into R, G, and B light.

Then, the R, G, B light separated from the illumination optical system installed in front of the color separation wheel is effectively irradiated to the screen display area of the liquid crystal display device, and the PBS (Polarized Beam Splitter) installed in front of the illumination optical system is separated from the illumination optical system. Only the light traveling in a predetermined direction is separated from the light to be cut and transferred to the reflective liquid crystal display device installed under the PBS.

The liquid crystal display device transmits a predetermined image signal to the PBS due to electrical and optical properties, and the PBS selects each polarization state for the image to be transmitted to the projection lens formed on the PBS.

The projection lens then forms an image signal of the liquid crystal display element on the screen.

Such a projection display device is advantageous in terms of price competitiveness due to low production cost since only one liquid crystal display device is used. However, since the color separation wheel continuously rotates by the motor, only the necessary color is passed through the light incident on the color separation wheel and the remaining color is blocked, thereby reducing the utilization efficiency of light by 1/3.

On the other hand, the projection type display device in which three liquid crystal display elements are built will be described as follows.

When light is emitted from the lamp, the light emitted from the lamp is effectively irradiated to the screen display area of the liquid crystal display by the illumination optical system installed at the bottom of the lamp, and the red dichroic mirror installed at the bottom of the illumination optical system is emitted from the illumination optical system. R light is transmitted in the vertical direction and the remaining G and B light is reflected in the horizontal direction.

Here, the R light reflected by the red dichroic mirror is incident on the red liquid crystal display device after passing through the first BPS after the reflection of the first reflection mirror provided under the red dichroic mirror.

On the other hand, the G, B light transmitted through the red dichroic mirror travels in the horizontal direction and hits the green dichroic mirror installed to be parallel to the red dichroic mirror. At this time, the G light is reflected in the vertical direction by the green dichroic mirror and then enters the green liquid crystal display device through the second PBS, and the remaining B light passes through the green dichroic mirror.

The B light passing through the green dichroic mirror is incident to the blue liquid crystal display device after passing through the third PBS.

As described above, each of the liquid crystal display elements to which the R, G, and B light is incident, modulates the R, G, and B light in accordance with the given image signal and emits the light toward the prism provided in front of each liquid crystal display element.

The prism synthesizes the R, G, and B light emitted from the three liquid crystal display elements and transmits the light to the projection lens installed in front of the prism.

The projection lens then forms an image signal transmitted from the three liquid crystal display elements on the screen.

As described above, the projection type display device in which the three liquid crystal display elements are installed has good light utilization efficiency, but the price increases because three liquid crystal display elements are used.

Accordingly, it is an object of the present invention to improve light utilization efficiency in a projection display device in which one liquid crystal display device is installed.

Other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1 is a conceptual diagram illustrating the structure of a projection display device according to the present invention;

FIG. 2 is an explanatory diagram for explaining a path in which light is incident and emitted to an LCD according to the present invention by enlarging part A of FIG. 1; FIG.

In order to achieve the above object, the present invention provides at least two dichro, which selectively reflects the light emitted from the lamp to the R light, the G light, and the B light and passes the remaining light to the emission surface side of the lamp from which the light is emitted. A color separation optical system including a blade mirror is provided, and a PBS for selectively passing and reflecting only light that vibrates in a predetermined direction is installed in a direction in which the R, G, and B light separated from the color separation optical system are reflected, and a lower part of the PBS is provided. In addition to focusing the R, G, and B light separated by the color separation optical system to each of the R, G, and B pixels, a reflective liquid crystal display device for controlling the incidence and exit angle of the R, G, and B light is installed. On the top of the PBS, a projection lens is provided to form an image signal emitted from the liquid crystal display on the screen.

For example, the color separation optical system includes a red dichroic mirror that reflects only R light toward PBS, a green dichroic mirror that reflects only G light toward PBS, and a blue dichroic mirror that reflects only B light toward PBS. In R, G, B pixels are arranged vertically in the order they are arranged.

As another example, the color separation optical system includes two dichroic mirrors for selectively reflecting only light of a predetermined color among R, G, and B light, and one color of light that passes through two dichroic mirrors farthest from the light source. It is composed of a reflecting mirror reflecting toward the PBS.

Preferably, the red, green, and blue dichroic mirrors or the two dichroic mirrors and the reflecting mirrors may be introduced into the R, G, and B pixels of the liquid crystal display corresponding to each other. Is installed with a tilt.

Preferably, the liquid crystal display device includes R, G, and B pixels that each of the R, G, and B light are incident to each other and reflect at the same angle as the incidence angle of the R, G, and B light; A lower substrate having switching elements electrically connected to the B pixels to turn on, off the R, G, and B pixels, and attached to the upper surface of the lower substrate so as to face the lower substrate. The common electrode is formed on the opposite surface, and the R, G, B light incident on the liquid crystal display device is focused on each of the corresponding R, G, and B pixels on the surface facing the PBS. Liquid crystal which is injected between the upper substrate and the lower substrate and the upper substrate on which the microlenses are controlled to have the same exit angle, and adjusts the amount of R, G, and B light by the potential difference between the R, G, and B pixels and the common electrode. It includes.

Hereinafter, the structure and operation of the projection display device according to the present invention will be described with reference to FIGS. 1 and 2.

Projection type display device 100 according to the present invention is perpendicular to the light source 110, the illumination optical system 120, the illumination optical system 120 is installed below the light source 110 to be perpendicular to the light source 110 in FIG. It is installed at the front of the color separation optical system 130, the color separation optical system 130 is installed in the lower portion of the illumination optical system 120, so as to be parallel to the color separation optical system 130 so as to selectively reflect only the light vibrating in a predetermined direction Or a reflective liquid crystal display device 160 installed below the PBS 140 so as to be perpendicular to the PBS 140 and a PBS 140 to be transmitted therethrough, or an upper portion of the PBS 140. It is composed of a projection lens 180 for binding the image signal to the screen 190.

Among the above-described components, the configuration of the light source 110, the illumination optical system 120, the color separation optical system 130, and the liquid crystal display device 160 will be described in more detail as follows.

The light source 110 surrounds the lamp 112 and the lamp 112 that emit radial rays, and a surface facing the illumination optical system 120 is opened to emit the emitted light emitted from the lamp 112 as a substantially parallel ray. It is composed of a reflective cover 114.

The illumination optical system 120 is an apparatus for effectively irradiating the light emitted from the lamp 112 to the screen display area of the liquid crystal display device 160. The first optical lens array 122, the second multi lens array 124, and The superimposed lens 126 is comprised.

The first multi-lens array 122 is installed between the light source 110 and the second multi-lens array 124, and on one surface facing the light source 110, small lenses close to a rectangular shape are arranged in a matrix to form a light source. The light emitted from 110 is divided into a plurality of partial light beams, and each divided partial light beam is condensed near the second multi-lens array 124.

The second multi-lens array 124 is installed between the first multi-lens array 122 and the overlapping lens 126, and the light passing through the first multi-lens array 122 receives light through the overlapping lens 126. In order to effectively illuminate the screen display area of the liquid crystal display device 160, small lenses are arranged in a matrix form on one surface facing the first multi lens array 122 to correspond to the lenses of the first multi lens array 122. It is.

The superposition lens 126 superimposes the light passing through the second multi lens array 124 on the liquid crystal display device 160, and is provided between the second multi lens array 124 and the color separation optical system 130. .

The color separation optical system 130 according to the present invention is a device that separates R, G, and B light from light passing through the superimposed lens 126.

The color separation optical system 130 includes a red dichroic mirror 132 and a red dichroic mirror 132 that selectively reflect red wavelength bands from the light passing through the superimposed lens 126 and allow light of the remaining wavelengths to pass. The green dichroic mirror 134 selectively reflects the green wavelength band from the transmitted light and passes the remaining light, and the blue dichroic reflects the remaining light passed through the green dichroic mirror 134, that is, the blue wavelength band. The blade mirror 136 is configured.

The reflective mirror may be installed instead of the dichroic mirror which is installed last in the red, green, and blue dichroic mirrors 132, 134, and 136 described above. This is because when the light passes through the first second dichroic mirror based on the superimposed lens, two colors of light from the R, G, and B light are separated and reflected toward the PBS, so that the other color is incident on the reflection mirror. to be.

Here, the red, green and blue dichroic mirrors 132, 134 and 136 are arranged in the vertical direction of the illumination optical system 120 with different inclinations, and the red, green and blue dichroic mirrors 132, 134 and 136 are separated. It is necessary to have an inclination in which the R, G, and B light can be easily incident on the respective R, G, and B pixels to be described later. In FIG. 1, dichroic mirrors are arranged in order of red, blue, and green.

Meanwhile, the liquid crystal display device 160 according to the present invention has a lower substrate 161 and an upper substrate attached to face the lower substrate 161 on the upper surface of the lower substrate 161 as shown in FIG. 2. 170 and a liquid crystal 168 injected between the lower substrate 161 and the upper substrate 170 to adjust the amount of light by the potential difference between the lower substrate 161 and the upper substrate 170.

On the upper surface of the lower substrate 161, R, G, B pixels 162, 164, 166 reflecting the respective R, G, B light passing through the upper substrate 170 and the liquid crystal 168, and each of the R, G, A switching element (not shown) is formed that is electrically connected to the B pixels 162, 164, 166 to turn on / off the R, G, B pixels 162, 164, 166 so that a predetermined image signal is generated.

Here, the upper surface of the R, G, B pixels 162, 164, 166 has a predetermined shape so that the R, G, B light is reflected at an angle equal to the angle when the R, G, B pixels are incident on the R, G, B pixels 162, 164, 166, respectively. For example, the upper surface of the B pixel 164 positioned between the R pixel 162 and the G pixel 166 is formed flat, and the R pixel 162 and the G pixel 166 have a predetermined slope B It is formed to be inclined toward the pixel 164. The reflective film 167 reflecting the R, G, and B light is formed on the upper surface of the R, G, and B pixels 162, 164, and 166.

Meanwhile, a common electrode 172 that generates a potential difference between the liquid crystal 168 together with the R, G, and B pixels 162, 164, and 166 on the lower surface of the upper substrate 170 that faces the R, G, and B pixels 162, 164, and 166. ) Is formed, and has a predetermined curvature on the surface of the upper substrate 170 facing the PBS 140, each of the R, G, B corresponding to the R, G, B light incident on the liquid crystal display device 160 A plurality of micro lenses 174 are formed to focus the pixels 162, 164, and 166 and to control the incidence angle and the outgoing angle of the R, G, and B light to be the same.

As shown in FIG. 2, one micro lens 174 covers one R pixel 162 and one G pixel 166 and one B pixel 164.

The operation of the projection display device having such a configuration will be briefly described as follows.

When power is applied to the lamp 112 and the light is emitted to the illumination optical system 120, the illumination optical system 120 transmits the light to the partial light beam so that the incident light can be effectively illuminated on the screen display area of the liquid crystal display device 160. The light is separated into the color separation optical system 130 and emitted.

Then, the light incident on the color separation optical system 130 is first separated by the red dichroic mirror 132, the R light is reflected to the PBS 140 at a predetermined angle and the remaining light is transmitted in the vertical direction. .

The light transmitted through the red dichroic mirror 132 is incident to the PBS 140 with the B light separated by the blue dichroic mirror 134 and has an angle of about 90 °. After passing through the blue dichroic mirror 134, the green dichroic mirror 136 is reflected toward the PBS 140 at an angle different from that of the R light and the B light.

The PBS 140 emits only the R, G, and B light propagating in the predetermined direction from the incident R, G, and B light toward the liquid crystal display device 160.

Thereafter, the R, G, and B light emitted toward the liquid crystal display device 160 are refracted by the curvature of the microlens 174, as shown in FIG. 2, to form the respective R, G, and B lights formed on the lower substrate 161. The pixels are focused on 162, 164, and 166. That is, R light is focused on each R pixel 162, B light is focused on each B pixel 164, and G light is focused on each G pixel 166.

The R, G, and B light focused on each of the R, G, and B pixels 162, 164, and 166 are reflected by the reflective film 167 formed on the upper surface of the R, G, and B pixels 162, 164, and 166. R, G, and B light are reflected by the same path as the incident path by the reflective surfaces of the R, G, and B pixels 162, 164, and 166 processed into shapes. The R, G, and B light reflected by the same path as the incident path are refracted by the curvature of the microlens 174 and emitted at the same angle as the angle when the microlens 174 is incident on the microlens 174.

The light emitted from the liquid crystal display device 160 is synthesized to generate a predetermined image signal, which passes through the PBS 140 and forms an image on the screen 190 through the projection lenses 180. .

As described above, since the projection display device according to the present invention uses all of the light emitted from the light source and incident on the color separation optical system after being separated into three primary colors of light, three liquid crystal display elements are used. The effect can be as high as the projection display element.

In addition, since a single liquid crystal display element is used in the projection display device according to the present invention, the cost of the projection display device can be reduced.

Claims (6)

A light source for generating light; An illumination optical system installed on an emission surface side of the light source from which the light is emitted, and a color separation optical system installed on the light emission surface side of the illumination optical system to separate and reflect light emitted from the illumination optical system into red, green, and blue light; A PBS installed in a direction in which the red, green, and blue light separated by the color separation optical system is reflected, reflecting and transmitting light traveling in a predetermined direction; A liquid crystal display device disposed below the PBS and configured to generate a predetermined image signal by controlling the angle when the red, green, and blue light is incident to the angle when the red, green, and blue light is emitted; A projection lens installed on an upper portion of the PBS to form an image signal of the liquid crystal display on a screen; The liquid crystal display device Each of the red, green, and blue light is incident to each other, and the R, G, and B pixels reflect each other at the same angle as the incidence angle of the red, green, and blue light; A lower substrate on which switching elements are electrically connected to turn on / off the R, G, and B pixels; It is attached to the upper surface of the lower substrate to face the lower substrate, the common electrode is formed on the surface facing the R, G, B pixels, and the red incident on the liquid crystal display device on the surface facing the PBS An upper substrate on which microlenses are focused on each of the R, G, and B pixels corresponding to the green, blue, and blue light to control the incidence angle and the exit angle of the red, green, and blue light to be the same; And a liquid crystal injected between the lower substrate and the upper substrate to control the amount of the red, green, and blue light by a potential difference between the R, G, and B pixels and the common electrode. Transmissive display device using. The method of claim 1, wherein the color separation optical system A red dichroic mirror which separates red light from the light emitted from the illumination optical system and reflects the red light toward the PBS and transmits the remaining green and blue light; A green dichroic mirror which separates green light from the transmitted green and blue light and reflects it toward the PBS, and passes blue light; And a blue dichroic mirror which separates the transmitted blue light and reflects it toward the PBS. 3. The red, green, and blue dichroic mirrors of claim 2, wherein the red, green, and blue dichroic mirrors each have a slope for easily injecting the red, green, and blue light separated from each other into the respective R, G, and B pixels. Projection type display device using a liquid crystal display element, characterized in that arranged. The dichroic mirror according to claim 1, wherein the color separation optical system is provided with two dichroic mirrors for selectively reflecting only light of a predetermined color from the light emitted from the illumination optical system and emitting the remaining light; A transmissive display device using a liquid crystal display device, characterized in that it comprises a reflection mirror that reflects the remaining one color of light passing through the long dichroic mirrors toward the PBS. The pixel of claim 1, wherein the red, green, and blue light are formed in the middle of the R, G, and B pixels so that the angle when the light is incident to each of the R, G, and B pixels is the same as the reflected angle. And an upper surface of a predetermined pixel is formed flat, and pixels formed on both sides of the predetermined pixel are formed to be inclined toward the predetermined pixel with a predetermined inclination. The image display using the liquid crystal display of claim 1, wherein the micro lenses have a predetermined curvature, and one micro lens covers one R pixel, one G pixel, and one B pixel. Device.