JP2002365587A - Color filter device of projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange a reflection-type filter of a disk-shape resolving a white ray to colors of R, G and B in time-division manner in a horizontal direction and at a bottom of a cabinet, and thereby reduction in thickness of the cabinet is attained. SOLUTION: In a color filter 1, a disk surface is divided to three regions of R, G, B with a central drive shaft 2 as a center, the filter resolving a white beam into color beams of R, G and B and reflecting is disposed, is arranged in a horizontal direction and is rotated at a prescribed speed through driving of a drive shaft. The white ray from a light source is reflected to the color filter by a mirror surface 3a of a triangle mirror 3, color-resolved ray is reflected by a mirror surface 3b and is then output. Output ray advances over extension of the path of an incident ray. Otherwise a planar mirror may be arranged with a prescribed inclination instead of the triangle mirror. In this case, the course of the output ray is in a direction which is different from the extension of the path of the incident ray.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter device for a projector, and more particularly to a color filter device for separating white light from a light source by time division.

[0002]

2. Description of the Related Art In a projector device, a white light beam from a light source is time-divisionally divided into red (R) and green (G) using a color filter.
And blue (B), the polarization planes are aligned by a polarization beam splitter, and time-divisionally driven by R, G, and B video signals. For example, an LCD (liquid crystal element) or a DMD (Digital
Micro-mirror device) and the like, and a method of projecting a modulated image light beam on a screen by a projection lens is known. The color filter in this case is, for example, as shown in FIG.
As shown in the figure, the filters for the wavelengths of R, G, and B are arranged in a disk shape, rotated by driving the drive shaft 42, and the white light from the light source is separated into R, G, and B in time division. As shown in (b), when the wavelength range is switched by the rotation of the color filter 41, the light passes through the boundary of the filter, as shown in (b).
An unusable dead zone occurs. In order to reduce the ratio of the dead zone, the light passage area is set as close to the outer periphery as possible. To further reduce the ratio, the diameter of the color filter 41 needs to be increased.
However, in the case of a configuration in which the color filters 41 are arranged vertically, the height of the device is increased to cover the color filters 41, which hinders a case where the device is small and thin.

[0003]

SUMMARY OF THE INVENTION In view of the foregoing, the present invention has a color filter disposed horizontally at the bottom of a housing, and another optical filter is provided on a portion of the color filter other than a light beam entrance / exit portion. System components and electric circuit components can be arranged, and a color filter with a large diameter can be used.
It is another object of the present invention to reduce the size of the device.

[0004]

In order to achieve the above object, a color filter device for a projector according to the present invention comprises:
The disk surface is divided into a red region, a green region, and a blue region around a drive shaft provided at the center of the disk surface, and white light is divided into red, green, and blue regions in each of the three divided regions. A color filter provided with a filter for color separation and reflection into light rays, and a white light ray incident from a light source is reflected toward the color filter, and a light ray separated and reflected by the color filter is incident and reflected. The color filter is arranged so that the disk surface is in the horizontal direction, and is rotated at a predetermined speed by driving the drive shaft, and the white light is red, green, and blue in time division. It is configured to be separated into light beams and output.

The mirror is a triangular mirror in which mirrors are formed on two surfaces of a triangular prism. One of the mirror surfaces reflects white light incident from the light source toward the color filter. The reflected light beam is incident on the other mirror surface, reflected and output in a predetermined direction, and the path of the white light beam entering the triangular mirror from the light source and the path of the light beam output from the mirror are different. Two mirror surfaces are formed so as to be on the same line.

[0006] Alternatively, the mirror is a flat mirror, and the flat mirror reflects white light incident from the light source toward the color filter, and receives light reflected by being separated by the color filter. The light is reflected and output in a predetermined direction.

In this case, the path of the light beam reflected and output by the flat mirror is in a different direction from the extension of the course of the incident light beam on the flat mirror.

[0008] A lens may be provided on the upper surface of the color filter in the incident path of the white light beam to suppress the spread of the incident light beam.

In addition, a light diffusion preventing plate is provided below the color filter, and a cooling fan is attached to the drive shaft of the color filter between the color filter and the light diffusion preventing plate, so that the color filter leaks. The light diffusion preventing plate may be cooled by the cooling fan to prevent the transmitted light from being diffused.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings. FIG. 1 is a perspective view of a main part of an embodiment of a color filter device of a projector according to the present invention. In the figure, 1 is a color filter, 2 is a drive shaft provided at the center of the disk surface of the color filter 1, and 3 is a triangular mirror. The color filter 1 divides the disk surface into three regions of R, G and B around the drive shaft 2 and separates white light into light of wavelengths of R, G and B in the three divided regions. A filter for reflecting light is provided, and is arranged so that the disk surface is horizontal. The triangular mirror 3 has mirror surfaces 3a and 3b formed on two surfaces of a triangular prism, and emits white light emitted from a light source in the horizontal direction to one mirror surface.
3a, is reflected toward the color filter 1, and the light beam reflected by the color filter 1 is incident on the other mirror surface 3b, and is reflected and output in the horizontal direction. The color filter 1 is rotated at a predetermined speed by driving the drive shaft 2,
The white light incident through the mirror surface 3a is color-separated into R, G, and B in a time-sharing manner, and output through the mirror surface 3b of the triangular mirror 3. The color-separated R, G, and B light beams are aligned in a polarization plane by a polarization beam splitter (not shown), and are synchronized with the color filter 1 using the R, G, and B video signals, and are time-divisionally driven to an LCD or DMD. Incident, modulated,
R, G, and B image light rays are projected on a screen by a projection lens. The triangular mirror 3 has mirror surfaces 3a and 3b so that the path of the white light beam incident from the light source and the paths of the output R, G, and B light beams are collinear.

FIG. 2 shows an example in which a flat mirror 11 is used in place of the triangular mirror 3. The flat mirror 11 is arranged at a predetermined angle with respect to the surface of the color filter 1. The color filter 1 is arranged so that the disk surface is in the horizontal direction, and is rotated at a predetermined speed by driving the drive shaft 2. The white light from the light source is reflected by the flat mirror 11 and
, Color-separated into R, G, and B in time division, reflected,
The light enters the flat mirror 11 and is reflected and output. The path of the output light (R, G, B light) is in a different direction from the extension of the path of the incident light (white light). By appropriately setting the inclination angle of the flat mirror 11, for example, On the other hand, it is possible to set according to the layout of the optical system components, the electric circuit components, and the like such that the output light beam can be output in the direction of 90 °.

When the wavelength region of the reflected light beam is switched from R to G, G to B, and B to R by rotation of the color filter 1, the incident region of the light beam on the color filter 1 is at the boundary between the two filters. Two matching filters interfere,
A dead zone becomes unavailable. In order to reduce the ratio of the dead zone to the effective region, the light incident region is set as close to the outer periphery of the color filter 1 as possible. In order to further reduce the ratio, as shown in FIG. A lens 21 (convex lens) may be provided on the incident optical path. Thereby, the spread of the incident light beam is suppressed, the incident area of the light beam is narrowed, and the ratio of the dead zone can be reduced. It is effective to increase the diameter of the color filter 1 as much as possible. However, as described above, in the present invention, the color filter 1 is arranged in the horizontal direction. By arranging the color filter 1 under the optical system component and the electric circuit component, it is possible to increase the diameter, and to reduce the ratio of the dead zone, which is at the same time, This is effective when the housing is formed thin.

A strong light from a light source is incident on the color filter 1, and a part of the light leaks through the color filter 1. For this reason, as shown in FIG. 4, a light diffusion prevention plate 32 is provided below the color filter 1 so that light rays leaking through the color filter 1 do not leak to the outside of the housing. In this case, the temperature of the light diffusion preventing plate 32 rises due to the heat of the light beam. As a countermeasure, a cooling fan 31 is attached to the drive shaft 2 between the color filter 1 and the light diffusion preventing plate 32, and provided.
The air is blown to the light diffusion prevention plate 32 and cooled. The air from the cooling fan 31 cools the light diffusion prevention plate 32 and at the same time
Since the light is repelled at 32, it reaches the color filter 1 and the color filter 1 is also cooled.

[0014]

As described above, according to the color filter device of the projector according to the present invention, the incident light beam is reflected by the mirror and is incident on the disk-shaped reflection type color filter. Since the reflected light is reflected again by the mirror and output, the color filter is disposed horizontally at the bottom of the projector housing, and other than where the light enters and exits, another color filter is placed above the color filter. It is possible to arrange mechanical parts and electric circuit parts, it is possible to increase the diameter of the color filter,
The ratio of the dead zone can be reduced, and at the same time, the housing can be made thin. The mirror is a triangular mirror with mirrors formed on two surfaces of a triangular prism. One mirror surface reflects a white light beam from a light source toward a color filter, and a light beam from the color filter reflects on the other mirror surface. By outputting the light, the path of the output light can be made collinear with the light incident on the mirror from the light source.
Further, if a flat mirror is used, the path of the output light beam can be set in a direction different from that of the incident light beam, so that the degree of freedom of the layout of the optical system can be expanded. Further, by disposing the convex lens in the incident optical path of the color filter, the spread of the incident light can be suppressed, and the ratio of the dead zone can be reduced. In addition, a part of the incident light leaks through the color filter, but since the light diffusion preventing plate is provided below the color filter, the leaked light does not leak out of the housing. In this case, the temperature of the light diffusion preventing plate rises due to the heat of the light beam. However, since the cooling fan is provided on the drive shaft of the color filter, the temperature rise of the light diffusion preventing plate is suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an embodiment of a color filter device of a projector according to the present invention.

FIG. 2 is a perspective view of a main part of another embodiment of the color filter device of the projector according to the present invention.

FIG. 3 is an example in which a lens is provided at an incident position on the color filter of FIG. 2;

FIG. 4 is a side view of a main part of an example in which a light diffusion preventing plate and a cooling fan are provided under a color filter.

FIG. 5 is an example of a conventional color filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Color filter 2 Drive shaft 3 Triangular mirror 3a, 3b Mirror surface 11 Flat mirror 21 Lens 31 Cooling fan 32 Light diffusion prevention plate 41 Color filter 42 Drive shaft

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 21/14 G03B 21/14 Z H04N 9/31 H04N 9/31 C

Claims (7)

[Claims] 1. The disk surface is divided into a red region, a green region and a blue region around a drive shaft provided at the center of the disk surface, and a white light beam is applied to each of the three divided regions. A color filter provided with a filter for separating and reflecting green and blue light rays, and reflecting a white light ray incident from a light source toward the color filter, and being separated and reflected by the same color filter. A mirror that receives, reflects and outputs light rays, arranges the color filters so that the disk surface is horizontal, rotates the drive light at a predetermined speed by driving the drive shaft, and time-divides the white light rays into red light. , A color filter device of a projector configured to perform color separation into green and blue light beams and output the separated light beams. 2. The mirror is a triangular mirror in which mirrors are formed on two surfaces of a triangular prism. One of the mirror surfaces reflects white light incident from the light source toward the color filter. 2. The color filter device for a projector according to claim 1, wherein the color-separated and reflected light is incident on the other mirror surface, reflected, and output in a predetermined direction. 3. The two mirror surfaces of the triangular mirror are formed such that the path of a white light beam incident from the light source and the path of a light beam output from the mirror are on the same line. A color filter device for a projector according to the above. 4. The mirror is a flat mirror, and the flat mirror reflects a white light beam incident from the light source toward the color filter, and receives a light beam separated and reflected by the color filter, 2. The color filter device for a projector according to claim 1, wherein the light is reflected and output in a predetermined direction. 5. The color filter device for a projector according to claim 4, wherein the path of the light beam reflected and output by said flat mirror is in a different direction from the extension of the course of the incident light beam on said flat mirror. 6. A color filter device for a projector according to claim 1, wherein a lens is provided on an upper surface of said color filter on an incident path of said white light beam to suppress spread of the incident light beam. . 7. A light diffusion prevention plate is provided below the color filter, and a cooling fan is attached to the drive shaft of the color filter between the color filter and the light diffusion prevention plate, and the color filter is leaked. 7. The color filter device for a projector according to claim 1, wherein the light beams are prevented from being diffused, and the light diffusion preventing plate is cooled by the cooling fan.