KR970008405B1 - Optic separator - Google Patents

Abstract

The beam splitter comprises a circular drum where a rotation axis is connected to the center of the top or bottom surface, and a color filter which splits the red, green and blue light beam from the inputted white light, being coated on the circumferential surface of the drum with the same width.

Description

Optical separator

1 is a schematic diagram of a general projection image display apparatus.

2 is a plan view of a conventional optical separator.

3 is a perspective view of an optical separator according to the present invention.

* Explanation of symbols for main parts of the drawings

2: optical separation 31: drum

33: rotating shaft 35: color filter

The present invention relates to an optical separator of a projection image display apparatus, and more particularly, to an optical separator of a projection image display apparatus capable of preventing color mixing.

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 image display device includes a CRT (Cathobe Ray Tube), but such a CRT image display device has good image quality, but there are problems such as an increase in weight and thickness as the screen is enlarged and a high price, and thus a large screen is limited. There is.

Projection type image display apparatuses include a large crystal display (Liquid Crystal Display: LCD), and the like. Such a large LCD can be thinned, and the weight can be reduced. However, such an LCD has a high light loss due to the polarization piece and a thin film transistor for driving the LCD is 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.

The projection image display apparatus is distinguished from using one-dimensional AMA and using 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, the projection type image display apparatus using the one-dimensional AMA pre-scans the M × 1 beams using the scanning mirror, and the projection image display apparatus using the two-dimensional AMA projects the M × N luminous fluxes to produce an array of M × N pixels. An image with a will be displayed.

1 is a schematic diagram of the general projection type image display apparatus 20.

The projection image display apparatus 20 includes a light source 1, an optical separator 2, an optical path controller 5, a light amount controller 13, and a screen 19.

The light source 1 emits white light of high brightness.

The optical splitter 2 sequentially separates red, green, and blue primary luminous fluxes from the white light. Each of the primary luminous fluxes is focused and reflected by the reflecting surface 15 of the light quantity controller 13, and the reflected primary luminous fluxes are dispersed again and are paralleled by the parallel lens 3.

The optical path controller 15 comprises a plurality of first primary beams paralleled by the parallel lens 3, consisting of an actuator 9 and mirrors 8 of an M × N array on a substrate 7. Reflects at secondary speeds. The secondary light beams for each of the primary light beams are light paths adjusted by the inclination of the mirrors 8. In addition, the second luminous fluxes are focused again by the parallel lens 3.

The light adjuster 13 consists of a reflective surface 15 having one or more gaps 17. The reflecting surface 15 reflects the primary light beam, which is separated into three primary colors and focuses again, to be dispersed again. In addition, the gaps 17 adjust and pass the amount of the second luminous flux focused by the parallel lens 3. In the gaps 17, the optical path controller 5 is not parallel to the parallel lens 3 in a state in which a driving voltage is not applied to the optical path controller 5, that is, there is no image signal. It is installed inclined by).

The screen 19 displays an image by synthesizing the second luminous fluxes whose light amount is sequentially projected to the front surface through the projection lens 18.

The general projection type image display device described above does not operate the optical path adjusting means in a state where power is applied so that about 50% of the second luminous fluxes are reflected on the screen. It was installed to have.

2 is a plan view of the optical separator 2 of the conventional projection image display apparatus.

The optical splitter 2 comprises a rotatable color wheel and has color filters 21 for transmitting the first, second, and red light beams from the incident white light and reflecting the remaining light beams. The color filters 21 are formed using respective dyes or color glasses and form a fan shape having the same rotation angle θ around the rotation axis. Therefore, the white light emitted from the light source 1 causes the cross section to be sequentially projected on the respective color filters 21, so that the optical separator 2 separates the white light into the primary luminous flux of red, green and blue. When the optical splitter 2 is rotated 60 times per second, that is, rotated once in 1/60 seconds, the white light shines the color filters 21 only for 1/80 seconds, respectively, so that the first order of each color Pass the light beam and reflect the remaining light Therefore, when color light separated by the fast rotation speed of the optical separator 21 is sequentially reflected on the optical path controller 5, visually, it is detected that the light beams of the three colors are mixed by the electric phase to represent a predetermined color.

As described above, the optical separator in which the red, green, and blue filters have the same rotation angle around the rotation axis separates the white light emitted from the light source into the primary luminous flux of red, green, and blue as it rotates.

However, the wheel-type optical splitter has a problem in that the filters have angles, and thus the luminous fluxes of two colors are simultaneously separated at the boundary, so that the image signal and the color do not match. In addition, the optical splitter transmits the primary luminous flux of the color to be separated from the white light and reflects the remaining luminous flux, thereby reducing the efficiency of the primary luminous flux of the separated color.

Accordingly, an object of the present invention is to provide an optical separator capable of preventing color mixing by matching a boundary between a filter and an image signal.

Another object of the present invention is to provide an optical path controller that can improve the efficiency of the primary luminous flux of the separated color.

The optical separator according to the present invention for achieving the above objects has a predetermined thickness and a circular drum having a rotation axis connected to the center of the upper or lower surface, and red from white light which is coated with the same width on the circumferential surface of the drum and is incident And a color filter for sequentially separating and reflecting the light beams of green and blue.

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

3 is a perspective view of the optical separator 2 according to the present invention.

The optical separator 2 has a drum 31 connected to the rotating shaft 33 and color filters 35 on the circumferential surface of the drum 33. The drum 31 is positioned so that the incident white light is irradiated on the circumferential surface, and the rotation shaft 33 is connected to the center of the upper or lower surface. The rotary shaft 33 is connected to a motor (not shown) to rotate in synchronization with the image signal to drive the drum 31.

The color filters 35 have the same width on the circumferential surface of the drum and are formed of dichroic mirrors reflecting only the primary luminous flux of a predetermined color from the incident white light and passing the remaining luminous flux. Accordingly, the color filters 35 separately reflect the primary luminous flux of a predetermined color from the white light incident from the light source 1 shown in FIG. Since the primary luminous flux of the predetermined color separated and reflected above does not pass through the color filters 35, it is possible to prevent light loss when passing through, thereby obtaining a light efficiency approaching 100%. A color filter set consisting of one color filter 35 separating and reflecting the primary luminous fluxes of red, green, and blue corresponds to an image signal of one frame, and the optical splitter 2 has n ( n is a natural number).

The above-described optical separator 2 synchronizes the color boundary of the color filters 35 so as to match the color boundary of the image signal applied to each of the actuators 9 of the optical path regulator 5 shown in FIG. That is, the width of each of the color filters 35 is made to match the period of the image signal. Therefore, a predetermined actuator of the optical path controller 5 when a conjugate image (shown with a dotted line) in which the image of the optical path controller 2 is kept to a minimum size passes through the color boundary of the color filters 35. 9), image signals corresponding to the color filters 33 through which corresponding portions of the conjugate image pass. Accordingly, the color boundary of the color filters 35 made of dichroic glass separating the light by reflecting only a predetermined amount of the first luminous flux from the incident white light coincides with the color boundary of the image signal applied to the actuators 9. The color purity can be improved by preventing mixed color.

As described above, the optical splitter according to the present invention passes a light beam except for a predetermined color from white light incident on a circumference of a circular drum having a predetermined thickness and connected to a rotating shaft at the center thereof, and reflects the first light beam of a predetermined color. Color filters composed of dichroic mirrors are separated to synchronize the color filters so that the boundary lines of the color filters and the color boundary of the image signal applied to the actuators are matched.

Therefore, the present invention has an advantage of preventing color mixing because the color boundary of the color filter and the color boundary of the image signal applied to the actuators are not overlapped with each other. In addition, since the reflected light is separated from the incident white light without passing through the primary luminous flux of a predetermined color, there is an advantage that the efficiency of the light can be improved by preventing the loss of light.

Although the present invention as described above has been described and illustrated with reference to the preferred embodiments, it will be understood by those skilled in the art that various modifications may be made without departing from the spirit and scope of the present invention.

Claims (5)

A circular drum having a predetermined thickness and having a rotating shaft connected to the center of the upper or lower surface, and having a same width on the circumferential surface of the drum, and sequentially separating and reflecting the luminous fluxes of red, green and blue from the incident white light Optical separator having a color filter to make. The optical separator of claim 1, wherein the drum is made of glass or plastic. The optical separator of claim 1, wherein the color filter is formed of a dichroic mirror. The optical splitter of claim 3, wherein the dichroic mirror prevents and reflects a passage of a light beam of a predetermined color from incident white light. 4. The optical separator of claim 3, wherein the color filter has a color boundary parallel to the axis of rotation.