JPH09211385A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a full color projected image free from color shading, and with good contrast. SOLUTION: The projector is provided with a color separation optical system for color-separating light from a light source 1, plural light valves 7R, 7B and 7G installed on each position where the light color-separated by the color separation optical system is guided, a color synthesis optical system 6 for synthesizing the light modulated by plural light valves 7R, 7B and 7G and a projecting lens 105 for projecting the light emitted from the color synthesis optical system. In this case, the color separation optical system 3 and the color synthesis optical system 6 are installed on such the position where a telecentric performance is maintained by a main light beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for projecting an image formed on a liquid crystal light valve onto a screen, and more particularly to a plurality of images formed on the liquid crystal light valve for a plurality of color components. The present invention relates to a device for illuminating with the illumination light of the color component of, and for synthesizing these images to project the synthetic image by a projection lens.

[0002]

2. Description of the Related Art Light from a light source is color-separated into R, G, and B lights by a three-color separation optical system, and the incident light of the R, G, and B lights separated by a light valve using a liquid crystal is signaled. 2. Description of the Related Art There is known a projection device that performs modulation, color-modulates the modulated lights emitted from these light valves, and projects them by a projection lens. A representative example of this device is shown in FIG.

In FIG. 5, light source light including R, G, and B light emitted from a lamp 301 is converted into a substantially parallel light beam by a concave mirror 302 and a condenser lens 303 arranged in the back, and is incident on a color separation optical system. To do. The color separation optical system includes a blue light (B light) reflection dichroic mirror 304 and a green light (G light).
Light) reflection dichroic mirror 305 and
B B reflected by the light reflection dichroic mirror 304
The light is reflected again by the mirror 307 to enter the B light liquid crystal light valve 311 and the G light reflected by the G light reflecting dichroic mirror 305 enters the G light liquid crystal light valve 310. Then, the red color (R light) that has passed through the dichroic mirror 305 is reflected by the mirrors 306 and 308 and is reflected by the R light liquid crystal light valve 30.
9 is incident. Each color light incident on each liquid crystal light valve is modulated based on the video signal of each color. That is, the video signal of each color is converted into an image having a transmittance distribution on each liquid crystal light valve. The lights emitted from these light valves enter a dichroic prism 312 having a R-light and B-light reflecting dichroic film as a combining optical system, and are combined into three colors. And is projected by a projection lens 313 on a screen (not shown) in an enlarged manner. In this conventional example, the dichroic mirrors 304 and 305 are configured to be parallel to each other.
A so-called cross dichroic mirror in which 04 and 305 are arranged in an X shape is also known as a conventional example.

[0004]

Generally, in a multi-layer film filter such as a dichroic mirror or a dichroic prism, its spectral characteristic has an angle dependence. Therefore, if the incident angle of the chief ray on the multilayer filter determined by the projection lens is not constant at any position of the multilayer filter, the spectral characteristics of the multilayer filter differ for each chief ray, and The problem of causing color shading occurs in. Further, since the liquid crystal light valve also has angle dependency, if the incident angle of the chief ray with respect to the liquid crystal light valve varies depending on the location, there is a problem that the contrast of the projected image becomes uneven due to this.

Therefore, it is an object of the present invention to obtain a full-color projected image with good contrast without causing color shading.

[0006]

In order to achieve the above-mentioned object, a projection apparatus according to one aspect of the present invention includes a color separation optical system for color-separating light from a light source and a color separation optical system for color separation. Light from a plurality of color signal light valves provided at positions where the separated lights are guided, a color combining optical system that combines the light modulated by the plurality of color signal light valves, and light from the color combining optical system A projection device having a projection lens for projecting, wherein the projection lens has an aperture stop, and the color separation optical system and the color synthesis optical system are such that the chief ray determined by the aperture stop of the projection lens maintains telecentricity. It is configured to be provided at the position where

[0007] In a preferred embodiment of the present invention,
An integrator and an illumination relay optical system for guiding light from the integrator to the color separation optical system are provided between the light source and the color separation optical system. In a preferred embodiment of the present invention, the integrator forms a surface light source, the illumination relay optical system forms an image of the surface light source, and the illumination relay optical system is a telecentric optical system on the image side of the surface light source. Configured to be.

In a preferred embodiment of the present invention,
The color separation optical system separates the light from the light source into an R light component, a G light component, and a B light component, and the plurality of color signal light valves includes
A light valve for R light, a light valve for G light, and a light valve for B light are provided, and a color separation optical system is provided between the color separation optical system and the R light, G light, and B light light valves. R
A relay optical system for R light, G light, and B light for guiding the light component, G light component, and B light component to the R light, G light, and B light light valves, respectively, is provided. .

In a preferred embodiment of the present invention,
An integrator that forms a surface light source and an illumination relay optical system that forms an image of the surface light source are provided between the light source and the color separation optical system, and the illumination relay optical system is telecentric to the image side of the surface light source. The relay optical system for R light, G light and B light forms a secondary image of the surface light source on the light valve for R light, G light and B light and is a secondary optical system. It is configured to be a telecentric optical system on the image side.

[0010] In a preferred embodiment of the present invention,
A polarization separation optical system that is provided between the light source and the color separation optical system and separates light from the light source into a first polarization component and a second polarization component that travel toward the color separation optical system, and illumination by the second polarization component. Combined optics provided in the optical path between the brightness signal light valve, the color combining optical system, and the brightness signal light valve to combine light from the color combining optical system and light that has passed through the brightness signal light valve. The combining optical system is configured so that the chief ray is provided at a position maintaining the telecentricity.

A projection apparatus according to another aspect of the present invention is a color separation optical system for color-separating light from a light source into an R light component, a G light component, and a B light component, and a color separation optical system. R light, G light and B light light valves provided at positions where guided light is guided, and color combining optics that combine light modulated by the R light, G light and B light light valves. A projection device having a system and a projection lens for projecting light from a color combining optical system, wherein an integrator and light from the integrator are guided to the color separating optical system between the light source and the color separating optical system. An illumination relay optical system is provided, and an R light component, a G light component, and a B light from the color separation optical system are provided between the color separation optical system and the R light, G light, and B light light valves.
R light, G light, and B light relay optical systems for guiding light components to the R light, G light, and B light light valves, respectively, are provided, and the illumination relay optical system includes a front group and a rear group. And a polarization splitting optical system for splitting the light from the light source into a first polarization component and a second polarization component directed to the color separation optical system, between the front group and the rear group of the illumination relay optical system. The projection lens has an aperture stop, and the projection device includes a light valve for a brightness signal, a relay optical system for a brightness signal that guides the second polarization component to the light valve for a brightness signal, and light from the color combining optical system. And a synthetic optical system for synthesizing light passing through the light valve for the luminance signal, and the color separation optical system, the color synthetic optical system, and the synthetic optical system are the telecentricity of the chief ray determined by the aperture stop of the projection lens. Is configured to be provided in a position that maintains the.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a perspective view for explaining the overall configuration of a projection apparatus according to the first embodiment, and adopts an XYZ coordinate system for the sake of simplicity. . FIG. 2 is an optical path diagram in the YZ plan view of the projection apparatus shown in FIG. 1, in which solid lines indicate the outermost marginal rays of the off-axis light flux, and broken lines indicate the principal rays of this off-axis light flux. The coordinate system in FIG. 2 corresponds to that in FIG.

In FIG. 1, light from a light source 1 including a lamp (not shown) and an elliptic mirror provided so that the lamp has a first focus passes through an infrared absorption filter (not shown) and an ultraviolet absorption filter (not shown). The light is focused on the incident surface of the rod integrator 2 made of a prism-shaped transparent optical member. The light that has entered the rod integrator 2 is repeatedly reflected by the inner surface of the rod integrator 2 and exits from the exit surface that faces the entrance surface. Here, a surface light source having a uniform light intensity distribution is formed on the exit surface. In other words, the exit surface is superposedly illuminated with light from virtual images of a plurality of light sources formed at the position of the entrance surface by the internal reflection of the rod integrator 2.

Next, the light from the exit surface of the rod integrator 2 travels along the -Z direction in the figure, and the first and second lights are emitted.
The light enters the illumination relay optical system including the illumination lenses 101 and 102. This illumination relay optical system has a focal length f1.
The first illumination lens 101 and the second illumination lens 102 having the focal length f2 are spaced by a distance f1 + f2, that is, the rear focus position of the first illumination lens 101 and the second illumination lens 1
It is configured so that the front focus position of 02 matches.

The light that has passed through the illumination relay optical systems 101 and 102 enters a cross dichroic mirror 3 in which an R light reflection dichroic mirror 3R and a B light reflection dichroic mirror 3B are combined in an X type. Here, the R component light is reflected by the R light reflection dichroic mirror 3R in the -X direction in the drawing, and the B component light is reflected by the B light reflection dichroic mirror 3B in the + X direction in the drawing. Then, the G component light passes through the R light reflection dichroic mirror 3R and the B light reflection dichroic mirror 3B, and in the figure-
Proceed in the Z direction.

At the rear focal position of the second illumination lens 102 in the optical paths of the R component light, the G component light and the B component light separated by the cross dichroic mirror 3, the image of the exit surface of the rod integrator 2 is shown in each color. It is formed for each component light. Now, the G component light will be described with reference to FIG. 2 showing the optical path of the G component light of each color component light. The G component light that has passed through the cross dichroic mirror 3 forms an image of the G component light on the exit surface of the rod integrator 2 at a position separated from the second illumination lens 102 by the optical path length f2. The G component light from this image is reflected by the bending mirror 4G and travels along the -Y direction in the figure. afterwards,
The G component light passes through the lens 103G, is then reflected by the bending mirror 5G, is deflected in the + Z direction in the drawing, and passes through the lens 104G. Here, the lenses 103G and 1
04G constitutes a relay optical system for G light and has a focal length f2.
Lens 103G and the lens 104G having the focal length f1 have a distance f1 + f2, that is, the lens 103G
The rear focal point and the front focal point of the lens 104G are arranged so as to coincide with each other.

The G component light from the G light relay optical system travels along the + Z direction and reaches the G light liquid crystal light valve 7G as a color signal light valve. The G light liquid crystal light valve 7G is arranged at a distance f1 from the G light relay optical system, and an image formed by the G component light on the exit surface of the rod integrator 2 is formed here.

Returning to FIG. 1, the R component light reflected in the -X direction by the cross dichroic mirror 3 is
Similar to the G component light, an image of the R component light on the exit surface of the rod integrator 2 is formed at a position away from the second illumination lens 102 by the optical path length f2. The R component light from this image is reflected by the bending mirror 4R and travels along the -Y direction in the figure. After that, the R component light is reflected by the lens 103R.
After passing through, the light is reflected by the bending mirror 5R, is deflected in the + Z direction in the drawing, and passes through the lens 104R. Here, the lenses 103R and 104R form a relay optical system for R light, and the lens 103R having the focal length f2 and the lens 104R having the focal length f1 have a distance f1 + f2, that is, the rear focus and the lens of the lens 103R. 104
It is arranged so that the front focus of R matches.

The R component light from the R light relay optical system travels along the + X direction and reaches the R light liquid crystal light valve 7R as a color signal light valve. The R light liquid crystal light valve 7R is arranged at a distance f1 from the R light relay optical system, and an image formed by the R light component on the exit surface of the rod integrator 2 is formed here.

The B component light reflected by the cross dichroic mirror 3 is, like the G component light, located at a position separated from the second illumination lens 102 by an optical path length f2, and is on the exit surface B of the rod integrator 2. An image is formed by the component light. The B component light from this image is reflected by the bending mirror 4B and travels along the -Y direction in the figure. After that, the B component light passes through the lens 103B and then is bent by the folding mirror 5.
It is reflected by B and is deflected in the + Z direction in the figure, and the lens 1
Pass 04B. Here, the lenses 103B and 104
B constitutes a relay optical system for B light, and the lens 103B having the focal length f2 and the lens 104B having the focal length f1 have an interval f1 + f2, that is, the rear focus of the lens 103B and the front focus of the lens 104B. Arranged to match.

The B component light from the B light relay optical system travels along the + X direction and reaches the B light liquid crystal light valve 7B as a color signal light valve. The B-light liquid crystal light valve 7B is arranged at a distance f1 from the B-light relay optical system, and an image formed by the B-light component on the exit surface of the rod integrator 2 is formed here.

Thus, an image of the exit surface of the rod integrator 2 having a uniform light intensity distribution is formed on the liquid crystal light valve for each color. That is, the liquid crystal light valve for each color is critically illuminated by a uniform surface light source. As described above, in the first embodiment, since the exit surface of the rod integrator 2 and the liquid crystal light valve for each color are arranged in a conjugate state, the exit surface of the rod-shaped integrator 2 having a prismatic shape is imaged by each liquid crystal light valve. The aspect ratio is determined so as to be similar to the display surface.

In the projection apparatus according to the first embodiment, the R-light relay optical system lens 103R, the G-light relay optical system lens 103G, and the B-light relay optical system lens 103B are The lenses 104R of the relay optical system for R light, the lens 104G of the relay optical system for G light, and the lens 104B of the relay optical system for B light are the same lens of focal length f1. It is a lens. In addition, the liquid crystal light valves 7R, 7B, 7 for each color are transmitted from the cross dichroic mirror 3 which is a color separation optical system.
The optical path lengths up to G are substantially the same.

The liquid crystal light valves 7R, 7B and 7G for each color will be described. Each liquid crystal light valve has a structure in which a liquid crystal panel is sandwiched between two polarizing plates that form a crossed Nicols. The liquid crystal panel includes a transparent glass substrate, and a transparent glass substrate and a glass plate on the glass substrate in order from the light incident side. It is composed of an active non-linear element (for example, a TFT) that selectively switches the formed grid-like pixel, an electrode that is combined with the active non-linear element, a liquid crystal layer, a counter electrode, and a transparent glass substrate. When the active element switches the electrode by the color signal for each color,
A voltage is applied between the counter electrodes facing this electrode, and the electric field causes the molecules of the liquid crystal to be aligned parallel to each other and perpendicular to the substrate. Therefore, the polarized light from the incident side polarizing plate passes through the liquid crystal panel as it is, and is absorbed by the emitting side polarizing plate forming the crossed Nicols. Here, a twisted structure is maintained in a portion that is not selected by the active element, and in this case, the polarization direction of the polarized light from the incident side polarization plate is changed by 90 degrees in accordance with the twist of the liquid crystal and is emitted from the panel. And passes through the exit side polarizing plate. As described above, each liquid crystal light valve is switched by each color signal to form an image corresponding to each color signal thereon, that is, the light passing through each liquid crystal light valve is modulated.

Now, as shown in FIG. 1, the R light reflection dichroic film 6R and the B light reflection dichroic film 6B are provided on the exit side of the liquid crystal light valves 7R, 7B, 7G for each color.
A cross dichroic prism 6 is provided so as to form a mold. The G component light modulated by the G light liquid crystal light valve 7G travels in the + Z direction in the drawing and passes through the R light reflection dichroic film 6R and the B light reflection dichroic film 6B. Further, the R component light modulated by the R light liquid crystal light valve 7R travels in the + X direction in the figure, and is + Z at the R light reflection dichroic film 6R.
The B component light that is reflected toward the direction and modulated by the B light liquid crystal light valve 7B proceeds toward the -X direction in the drawing and is reflected toward the + Z direction by the B light reflection dichroic film 6B. . That is, each color component light separated by the cross dichroic mirror 3 into three directions (R component light is + X direction, G component light is -Z direction, B component light is -X direction) passes through each liquid crystal light valve. After that, the direction opposite to the above three directions (R component light is −X direction, G component light is + Z direction,
The B component light is incident on the cross dichroic prism 6 in the + X direction, and each color component light is combined from the cross dichroic prism 6 in the opposite direction (+ Z direction) to the incident direction (-Z direction) to the cross dichroic mirror 3. Is ejected.

A projection lens system 105 is arranged on the exit side (+ Z direction side) of the cross dichroic prism 6. Here, this projection lens has an aperture stop (not shown), and the aperture stop is located at the rear focus (aperture stop side is the rear side) position of the lens group located closer to the cross dichroic prism 6 than the aperture stop. It is a configuration to be arranged.
The chief ray of the optical system of the projection device is determined by this aperture stop, and the cross dichroic prism 6 and the projection lens system 1 are set.
Between 05 and 05, the chief ray becomes parallel to the optical axis. That is, the projection lens system 105 is an optical system that is telecentric on the cross dichroic prism 6 side.

As shown in FIG. 2, in the projection apparatus according to the first embodiment, the optical path between the exit surface of the rod integrator 2 and the illuminating lens 101, the illuminating lens 102 and the G light relay lens are provided. Optical path between lens 103G and lens 104G of G light relay lens and projection lens system 1
In the optical path between the optical path and the optical path 05, the chief ray determined by the aperture stop of the projection lens system 105 becomes parallel to the optical axis. Further, although not shown in FIG. 2, an optical path between the illumination lens 102 and the lens 103R of the R light relay lens, R,
Lens 104R of optical relay lens and projection lens system 10
5, an optical path between the illumination lens 102 and the B-light relay lens 103B, and an optical path between the B-light relay lens 104B and the projection lens system 105. The chief ray determined by the aperture stop 105 is parallel to the optical axis. In other words,
The illumination relay optical system, the R light relay optical system, the B light relay optical system, and the G light relay optical system are both-side telecentric optical systems.

As described above, in the projection apparatus according to the first embodiment, the cross dichroic mirror 3 as the color separation optical system and the cross dichroic prism 6 as the color combining optical system both have the principal ray as the optical axis. Since it is provided in a position parallel to, that is, in a position where the principal ray maintains the telecentricity, there is an advantage that shading due to the angular characteristics of the color separation and color combining optical system does not occur. Furthermore, in the projection device according to the first embodiment, R
Since the liquid crystal light valves for light, B light, and G light are provided at positions where the chief rays maintain telecentricity, as in the color separation and color combining optical system, projection is performed according to the angle characteristics of the liquid crystal light valve. There is also an advantage that unevenness in image contrast does not occur, and as a result, an effect of being able to project a full-color image with excellent image quality is exhibited.

In the first embodiment, the image of the liquid crystal light valves for each color is formed on the screen (not shown) in a combined state, but the direction of the image on the screen is the same for each color component light. It goes without saying that the liquid crystal light valves for each color are driven as described above. [Second Embodiment] Next, referring to FIG. 3 and FIG.
A second embodiment according to the present invention will be described. FIG. 3 is a perspective view for explaining the overall configuration of the projection apparatus according to the second embodiment, and adopts an XYZ coordinate system for simplicity of description. FIG. 4 shows the YZ of the projection device shown in FIG.
FIG. 6 is an optical path diagram in a plan view, in which solid lines indicate the outermost marginal rays of the off-axis light flux, and broken lines indicate the principal rays of the off-axis light flux.
The coordinate system in FIG. 4 corresponds to that in FIG.

In FIG. 3, light from a light source 11 including a lamp (not shown) and an elliptic mirror provided so that the lamp has a first focus passes through an infrared absorption filter (not shown) and an ultraviolet absorption filter (not shown). , And is focused on the incident surface of the rod integrator 12 made of a prism-shaped transparent optical member. The light that has entered the rod integrator 12 is repeatedly reflected by the inner surface of the rod integrator 12 and exits from the exit surface that faces the entrance surface. Here, a surface light source having a uniform light intensity distribution is formed on the exit surface. In other words, this exit surface is
The rod integrator 2 is internally illuminated by the light reflected from the virtual images of the plurality of light sources formed at the position of the incident surface by the internal reflection.

Next, the light from the exit surface of the rod integrator 12 travels along the -Z direction in the figure and enters the illumination relay optical system including the first and second illumination lenses 201 and 202. In this illumination relay optical system, a first illumination lens 201 having a focal length f1 as a front group and a second illumination lens 202 having a focal length f2 as a rear group have an interval f1 + f.
2, that is, the rear focal position of the first illuminating lens 201 and the front focal position of the second illuminating lens 202 coincide with each other.

A first polarization beam splitter 13 is provided in the pupil space of this illumination relay optical system, that is, in the optical path between the first illumination lens 201 and the second illumination lens 202. Of the light from the first illumination lens 201 that enters the first polarization beam splitter 13, the first polarization component that is a P polarization component (linear polarization whose vibration direction is ± Y direction in the drawing) with respect to the polarization beam splitter 13 is , Which was placed on the exit side after passing through this polarization beam splitter 13.
The polarized light component (linearly polarized light whose vibration direction is ± X direction in the figure) in a state where the polarization direction is rotated by 90 degrees after passing through the / 2 wavelength plate 14 is incident on the second illumination lens.

The linearly polarized light that has passed through the illumination lens 202 is incident on a cross dichroic mirror 15 in which an R light reflection dichroic mirror 15R and a B light reflection dichroic mirror 15B are combined in an X type. Here, the R component light is reflected by the R light reflection dichroic mirror 15R in the figure -X.
The B component light is reflected in the + direction in the figure by the B light reflection dichroic mirror 15B. Then, the G component light passes through the R light reflection dichroic mirror 15R and the B light reflection dichroic mirror 15B and travels in the -Z direction in the figure.

At the rear focal position of the second illumination lens 202 in the optical paths of the R component light, the G component light and the B component light separated by the cross dichroic mirror 15, the image of the exit surface of the rod integrator 12 is colored. It is formed for each component light. Now, the G component light will be described with reference to FIG. 4 showing the optical path of the G component light of each color component light. The G component light that has passed through the cross dichroic mirror 15 is
An image of the G component light on the exit surface of the rod integrator 12 is formed at a position away from the second illumination lens 202 by the optical path length f2. The G component light from this image is reflected by the bending mirror 16G and travels along the -Y direction in the figure. After that, the G component light passes through the lens 203G, is then reflected by the bending mirror 17G, is deflected in the + Z direction in the drawing, and passes through the lens 204G. Here, the lenses 203G and 204G form a relay optical system for G light, and the lens 203G having the focal length f2 and the lens 204G having the focal length f1 are spaced by a distance f1 + f2, that is, the rear focal point of the lens 203G and the lens. It is arranged so that the front focal point of 204G is matched.

The G component light from the G light relay optical system travels along the + Z direction and reaches the G light liquid crystal light valve 18G as a color signal light valve. This G
The light valve 18G for light is arranged at a distance f1 from the liquid crystal relay optical system for G light, and an image formed by the G component light on the exit surface of the rod integrator 12 is formed here.

Returning to FIG. 3, the R component light reflected in the −X direction by the cross dichroic mirror 15 is located at a position separated from the second illumination lens 202 by the optical path length f2, like the G component light. , Rod integrator 12
An image is formed by the R component light on the exit surface of. The R component light from this image is reflected by the folding mirror 16R, and in the figure-
Proceed along the Y direction. After that, the R component light passes through the lens 203R, is then reflected by the folding mirror 17R, is deflected in the + Z direction in the drawing, and passes through the lens 204R. Here, the lenses 203R and 204R form a relay optical system for R light, and have a focal length f2.
And the lens 204R having the focal length f1 are arranged so as to have a distance f1 + f2, that is, the rear focus of the lens 203R and the front focus of the lens 204R are aligned.

The R component light from the R light relay optical system travels along the + X direction and reaches the R light liquid crystal light valve 18R as the color signal light valve. This R
The liquid crystal light valve 18R for light is arranged at a distance f1 from the relay optical system for R light, and an image by the R light component of the exit surface of the rod integrator 12 is formed here.

Further, the B component light reflected by the cross dichroic mirror 15 is, similarly to the G component light, at the position B away from the second illumination lens 202 by the optical path length f2, which is the B surface of the exit surface of the rod integrator 12. An image is formed by the component light. The B component light from this image is bent by the bending mirror 16B.
It is reflected by and travels along the -Y direction in the figure. After that, the B component light passes through the lens 203B, is then reflected by the folding mirror 17B, is deflected in the + Z direction in the drawing, and passes through the lens 204B. Here, the lens 203B
And 204B form a relay optical system for B light, and include a lens 203B having a focal length f2 and a lens 204 having a focal length f1.
B and the distance f1 + f2, that is, the lens 2
The rear focal point of 03B and the front focal point of the lens 204B are arranged so as to coincide with each other.

The B component light from the B light relay optical system travels along the + X direction and reaches the B light liquid crystal light valve 18B as a color signal light valve. This B
The liquid crystal light valve 18B for light is arranged at a distance f1 from the relay optical system for B light, and an image by the B light component of the exit surface of the rod integrator 12 is formed here.

As described above, the rod integrator 12 having a uniform light intensity distribution is provided on the liquid crystal light valve for each color.
An image of the exit surface of is formed. That is, the liquid crystal light valve for each color is critically illuminated by a uniform surface light source. Further, in the second embodiment, the illumination relay optical systems 201 and 202 form an image of the exit surface of the rod integrator 12 at f2 / f1 times, and each color relay optical system forms this image at f1 / f2. Re-image on each liquid crystal light valve at double. That is, an equal-magnification image of the exit surface of the rod integrator 12 is formed on each liquid crystal light valve.
As described above, in the second embodiment, the exit surface of the rod integrator 12 and the liquid crystal light valve for each color are in a conjugate arrangement, and the magnification relationship is the same. The vertical and horizontal sizes are determined so that the exit surface has the same size and shape as the image display surface of each liquid crystal light valve.

In the projection apparatus according to the second embodiment, the R-light relay optical system lens 203R, the G-light relay optical system lens 203G, and the B-light relay optical system lens 203B are The lenses have the same focal length f2, and the lens 204R for the R light relay optical system, the lens 204G for the G light relay optical system, and the lens 204B for the B light relay optical system have the same focal length f1. It is a lens. In addition, liquid crystal light valves 18R and 18R for respective colors are output from the cross dichroic mirror 15 which is a color separation optical system.
The optical path lengths up to B and 18G are substantially the same.

The liquid crystal light valves for each color 18R, 18B, 18G are switched by each color signal to form an image corresponding to each color signal, that is, pass through each color liquid crystal light valve. Which modulates the light to be emitted, and the liquid crystal light valves 7R and 7R for the respective colors in the first embodiment.
Since it has the same function as B and 7G, the description thereof is omitted here.

Now, the liquid crystal light valves for each color 18R, 1
On the exit sides of 8B and 18G, a cross dichroic prism 19 in which four right-angle prisms are combined is provided so that the R light reflection dichroic film 19R and the B light reflection dichroic film 19B are X-shaped. The G component light modulated by the G light liquid crystal light valve 18G travels in the + Z direction in the figure, and the R light reflection dichroic film 1 is formed.
9R and B light reflecting dichroic film 19B are transmitted.
The R component light modulated by the R light liquid crystal light valve 18R travels in the + X direction in the figure and is reflected by the R light reflection dichroic film 19R in the + Z direction.
The B component light modulated by the B light liquid crystal light valve 18B travels in the -X direction in the drawing and is reflected by the B light reflection dichroic film 6B in the + Z direction. That is, each color component light separated by the cross dichroic mirror 15 into three directions (R component light is + X direction, G component light is -Z direction, B component light is -X direction) passes through each liquid crystal light valve. After that, the light enters the cross dichroic prism 19 in the opposite direction to the above three directions (R component light is −X direction, G component light is + Z direction, and B component light is + X direction).
The respective color component lights are combined and emitted from the cross dichroic prism 19 in the opposite direction (+ Z direction) to the incident direction (−Z direction) to the cross dichroic mirror 15. At this time, the R component light from the R light liquid crystal light valve 18R is linearly polarized light vibrating in the ± Y directions, and the B component light from the B light liquid crystal light valve 18B is linearly polarized light vibrating in the ± Y directions. The G component light from the G light liquid crystal light valve 18G is linearly polarized light that vibrates in the ± Y directions. As described above, in the second embodiment, 1 / is provided between the polarization beam splitter 13 and the cross dichroic mirror 15.
Since the two-wave plate 14 is provided, the linearly polarized light from each color liquid crystal light valve is used to cross the dichroic prism 19
The dichroic films 19R and 19B can be S-polarized, and the spectral characteristics of the dichroic films 19R and 19B can be improved.

On the exit side (the + Z direction side) of this cross dichroic prism 19, a combined light relay optical system 20 is provided.
5, the light passing through the combining relay optical system 205 travels in the + Z direction, is deflected by the bending mirror 20 and travels in the + Y direction, and is a liquid crystal light valve for each color. Images of 18R, 18B, and 18G are formed at the same position, that is, a combined relay optical system forms a combined image I of the liquid crystal light valves 18R, 18B, and 18G for each color. The combining relay optical system 205 includes a lens 205 having a focal length f3 as shown in FIG.
And a lens 205 “having a focal length f4” is separated by a distance f3 + f4
It is possible to use those arranged in.

Now, the second polarized component reflected by the polarization beam splitter 13 (linearly polarized light whose vibration direction is ± X direction in the drawing) travels along the -Y direction in the drawing and has the third focal length f2. After passing through the illumination lens 206, the folding mirror 2
At 2, the light is reflected in the + Z direction in the figure. Here, the third
The illumination lens 206 has an optical path length of f1 + f2 with the first illumination lens 201, that is, the rear focus position of the first illumination lens 201 and the front focus position of the third illumination lens 206 match. Are arranged as follows. The light valve 23 for brightness signal is arranged at the rear focal position of the third illumination lens 206.

Here, the luminance signal relay optical system for forming the image of the rod integrator 12 on the luminance signal light valve 23 is the first illumination lens 201 of the illumination relay optical system as the front group and the rear group as the rear group. It is composed of the third illumination lens 206 of the luminance signal relay optical system, and the first illumination lens 201 is shared by the illumination relay optical system and the luminance signal relay optical system. Here, in the projection device according to the second embodiment, the second illumination lens 202 of the illumination relay optical system and the third illumination lens 206 of the luminance signal relay optical system use the same lens.

The brightness signal light valve 23 is structurally the color signal light valve 18R, 18B, 1 described above.
It is similar to 8G, but is larger in size than the color signal light valves 18R, 18B, and 18G and has a larger number of pixels. The relay optical system 201, 206 allows the brightness signal light valve 23
An enlarged image of the exit surface of the rod integrator 12 is formed on the top. At this time, the magnification of the magnified image on the brightness signal light valve 23 is given by f2 / f1. Therefore, the focal lengths of the first to third illumination lenses and the focal lengths f1 and f2 of the lenses of the relay optical system for each color are the light valve 23 for the brightness signal and the liquid crystal light valve 18 for each color.
It may be determined by the ratio of the sizes of R, 18B and 19G.

Luminance signal light valve 23 exit side (+
A polarization beam splitter 24 as a combining optical system is arranged on the Z direction side. Luminance signal light valve 2
The light emitted from 3 is linearly polarized light having a vibration direction of ± Y directions in the figure, and is P-polarized with respect to the polarization beam splitter 23.
Through the projection lens 207 and enters the projection lens 207 located on the exit side.

On the other hand, from the combined image I formed by the combining relay optical system 205, linearly polarized light having a vibration direction of ± Z directions in the figure advances along the + Y direction. This linearly polarized light passes through the half-wave plate 21 and has a polarization direction of 90 degrees.
After rotating by ± degrees, the polarization beam splitter 23
Incident on. Since this light is S-polarized with respect to the polarization beam splitter 23, it is reflected here, travels along the + Z direction in the drawing, and enters the projection lens 207. Here, the light valve 23 for brightness signal and the composite image I are in a mutually conjugate position with respect to the projection lens 207.

This projection lens 207 has an aperture stop (not shown), and the polarization beam splitter 2 has a larger aperture than this aperture stop.
In this configuration, the aperture stop is arranged at the rear focal point of the lens unit located on the third side (the aperture stop side is the rear side). This aperture stop determines the principal ray of the optical system of the projection device, and the principal ray becomes parallel to the optical axis in the optical path between the polarization beam splitter 23 and the projection lens system 207. That is, the projection lens system 207 is an optical system that is telecentric on the polarization beam splitter 23 side.

As shown in FIG. 4, in the projection apparatus according to the second embodiment, the optical path between the exit surface of the rod integrator 12 and the illumination lens 201, the illumination lens 202.
And the optical path between the lens 203G of the G light relay lens,
An optical path between the lens 204G of the G light relay lens and the lens 205 'of the combining relay optical system, an optical path between the lens 205 "of the combining relay optical system and the projection lens 207, and the third illumination lens 206 and projection. The chief ray determined by the aperture stop of the projection lens system 105 becomes parallel to the optical axis in the optical path between the lens 207. Further, although not shown in Fig. 4, the illumination lens 202 and the R light relay. Optical path between lens 203R of lens, lens 204R of relay lens for R light and lens 20 of relay optical system for combination
5 ', an optical path between the illumination lens 202 and the B light relay lens 203B, and an optical path between the B light relay lens 104B and the combining relay optical system lens 205'. Also in the projection lens system 207
The chief ray determined by the aperture stop of is parallel to the optical axis. In other words, the illumination relay optical system 201, 20
2, illumination relay optical system 201, 206, R light relay optical system 203G, 204G, B light relay optical system 203
B, 204B, G light relay optical system 203G, 204G
And the combining relay optical system is a double-sided telecentric optical system.

As described above, in the projection apparatus according to the second embodiment, the cross dichroic mirror 15 as the color separation optical system, the cross dichroic prism 19 as the color combining optical system, and the polarized beam as the combining optical system. Since both the splitter 24 and the splitter 24 are provided in a position where the principal ray is parallel to the optical axis, that is, the position where the principal ray maintains the telecentricity, the color separation and the color synthesizing optical system and the angle characteristic of the synthesizing optical system are used. There is an advantage that shading does not occur. Then, in the projection apparatus according to the second embodiment, the R light, B light, and G light liquid crystal light valves and the brightness signal light valve 23 are similar to the color separation and color combination optical system in that Since it is provided at a position where the telecentricity is maintained, there is also an advantage that the unevenness of the contrast of the projected image due to the angle characteristic of the liquid crystal light valve does not occur, and as a result, it is possible to project a full-color image of excellent image quality. .

In the projection device according to the second embodiment, the polarization beam splitter 13 as the polarization separation optical system is provided at a position where the telecentricity is not maintained. Since there is almost no influence on the color shading on the screen and the uneven contrast of the projected image, there is no problem.

Further, in the projection apparatus according to the second embodiment, the first illumination lens 201 of the relay optical system for illumination and the lenses 204R, 204G, 204B of the relay optical system for each color.
And the same type of lens having the focal length f1, and the second illumination lens 202 of the illumination relay optical system, the third illumination lens 206 of the luminance signal relay optical system, and the lenses 203R, 203G, 203B of the relay lenses for each color. Focal length f2
It is composed of the same type of lens. In this way, since the lenses forming the relay optical system for illumination, the relay optical system for luminance signals, and the relay optical system for each color are shared,
Cost reduction is possible.

In the second embodiment, the image of the liquid crystal light valve for each color and the image of the liquid crystal light valve for the brightness signal are formed on a screen (not shown), but the image is formed on the screen. It goes without saying that the liquid crystal light valve for each color and the liquid crystal light valve for luminance signal are driven so that the direction of the image is aligned with each color component light.

In the projection apparatus according to the second embodiment shown in FIGS. 3 and 4, the synthesizing relay optical system 205 has been described as consisting of two lens groups. From the field lens arranged near the exit side (+ Z direction side) of the dichroic prism 19, the field lens arranged near the combined image, and the lens group having a positive refractive power arranged between these two field lenses. It may be configured. Further, in the examples of FIGS. 3 and 4, the ½ wavelength plate 21 is arranged in the optical path between the composite image I and the polarization beam splitter 24, but instead, the composite image I and the bending mirror 20 are arranged. You may arrange | position in the optical path between and. In this way, the half-wave plate 21 may be arranged in the optical path between the dichroic prism 19 as the color combining optical system and the polarization beam splitter 24 as the combining optical system. Further, sheet-type half-wave plates can be used as the half-wave plates 14 and 21, and in this case, on the surfaces of prism members such as the polarization beam splitters 13 and 24 and the dichroic prism 19. It should be provided.

Further, in the example of FIGS. 3 and 4, the illumination relay optical system is constituted by the first and second illumination lenses 201 and 202, but instead it is sandwiched by two field lenses. You may comprise with the lens group of positive refracting power. In this case, when the polarization beam splitter 13 is arranged between the field lens on the side of the cross dichroic mirror 15 and the lens group having a positive refracting power, the same thing as the above field lens is provided in the optical path between the polarization beam splitters 13 and 24. To place. Further, the polarization beam splitter 13 is connected to the lens group having a positive refractive power and the rod integrator 1.
When arranging in the optical path between 2 and 2, the same lens group as the above-mentioned positive refracting power and the same field lens may be arranged in the optical path between the polarization beam splitters 13 and 24.

Further, although the rod integrator is used in the above-mentioned first and second embodiments, instead of it,
A fly-eye lens may be applied. Further, instead of using the lamp and the elliptical mirror as the light source, the lamp, the parabolic mirror, and the spherical mirror can be used. In the first and second embodiments, the chief ray is determined by the aperture stop of the projection lens system, but instead of / in addition to that,
It goes without saying that the aperture stop may be provided at a position conjugate with the position corresponding to the aperture stop of the projection lens system. For example, the first
In the embodiment, between the first illumination lens 101 and the second illumination lens 102 and / or the lenses 103R, 103G, 103B of the relay optical system for each color and the bending mirror 5R,
It may be provided at a position conjugate with the position corresponding to the aperture stop of the projection lens system 105 between 5G and 5B. Further, in the second embodiment, the lens 20 of the relay optical system for each color is provided between the first illumination lens 201 and the polarization beam splitter 13.
3R, 203G, 203B and folding mirrors 17R, 17
It may be provided at a position conjugate with the position corresponding to the aperture stop of the projection lens system 207 between G and 17B and / or in the combining relay optical system. By using an aperture stop provided in addition to such a projection lens system, it is possible to remove the internal reflected light and scattered light in the optical system of the projection device, improve the contrast of the projected image and prevent heating of the liquid crystal light valve. it can.

In the first and second embodiments, the field stop may be arranged at a position conjugate with the exit surface of the rod integrator 2 (12). Even by providing such a field stop, it is possible to remove the internal reflected light and scattered light in the optical system of the projection device, improve the contrast of the projected image and prevent the liquid crystal light valve from being heated.

As described above, the present invention is not limited to the above-mentioned embodiment and can take various forms.

[Brief description of drawings]

FIG. 1 is a perspective view showing a projection device according to a first embodiment of the present invention.

FIG. 2 is an optical path diagram of the projection device according to the first embodiment.

FIG. 3 is a perspective view showing a projection device according to a second embodiment of the present invention.

FIG. 4 is an optical path diagram of a projection device according to a second embodiment.

FIG. 5 is a diagram showing a conventional projection device.

[Explanation of symbols]

1, 11 Light source 2, 12 Rod integrator 13 Polarizing beam splitter 14, 21 1/2 wavelength plate 3, 15 Cross dichroic mirror 3R, 15R R Light reflection dichroic mirror 3B, 15B B Light reflection dichroic mirror 5R, 5B, 5G, 18R , 18B, 18G color signal light valve 6, 19 color combining dichroic prism 23 brightness signal light valve 24 polarizing beam splitter 205 combining relay lens 105, 207 projection lens system

Claims (7)

[Claims] 1. A color separation optical system for color-separating light from a light source, a plurality of color signal light valves provided at a position where the light separated by the color separation optical system is guided, and the plurality of color signal light valves. In a projection device including a color synthesizing optical system that synthesizes light modulated by a color signal light valve, and a projection lens that projects light from the color synthesizing optical system, the projection lens has an aperture stop, The projection apparatus, wherein the color separation optical system and the color combination optical system are provided at positions where a chief ray determined by an aperture stop of the projection lens maintains telecentricity. 2. Between the light source and the color separation optical system,
2. The projection apparatus according to claim 1, further comprising an integrator and an illumination relay optical system that guides light from the integrator to the color separation optical system. 3. The integrator forms a surface light source, the illumination relay optical system forms an image of the surface light source, and the illumination relay optical system is an optical system telecentric to the image side of the surface light source. The projection device according to claim 2, wherein the projection device is provided. 4. The color separation optical system separates light from the light source into an R light component, a G light component and a B light component, and the plurality of color signal light valves are R light light valves, G light components. A light valve for light and a light valve for B light, and an R light component from the color separation optical system between the color separation optical system and the R, G, and B light light valves. Relay light systems for R light, G light and B light for guiding the G light component and the B light component to the R light, G light and B light light valves, respectively. The projection device according to claim 1. 5. Between the light source and the color separation optical system,
An integrator that forms a surface light source and an illumination relay optical system that forms an image of the surface light source are provided, and the illumination relay optical system is a telecentric optical system on the image side of the surface light source, and the R light And G light and B light relay optical systems form a secondary image of the surface light source on the R light, G light and B light light valves, and are telecentric to the secondary image side. The projection device according to claim 4, which is an optical system. 6. Polarization separation provided between the light source and the color separation optical system to separate light from the light source into a first polarization component and a second polarization component directed to the color separation optical system. An optical system, a brightness signal light valve illuminated by the second polarized component, and an optical path provided between the color combining optical system and the brightness signal light valve. With light,
The optical system further comprises a combining optical system for combining the light that has passed through the brightness signal light valve, and the combining optical system is provided at a position where a chief ray maintains telecentricity. The projection device according to claim 5. 7. The light from the light source is converted into R light component, G light component and B light component.
A color separation optical system for performing color separation into light components, a light valve for R light, a light for G light, and a light for B light provided at a position where the light separated by the color separation optical system is guided, and the light for R light A light source for the G light and a light for the B light, and a projection lens provided with a projection lens for projecting light from the color synthesis optical system for synthesizing the light modulated by the light valve. An integrator and an illumination relay optical system for guiding light from the integrator to the color separation optical system are provided between the separation optical system, and the color separation optical system and the R light, G light, and B light are provided. Between the light valve for light and the R light component for guiding the R light component, the G light component, and the B light component from the color separation optical system to the R light, R light for G light, and R light for B light, respectively. A relay optical system for G light and B light is provided, and the relay for illumination is provided. The academic system has a front group and a rear group, and between the front group and the rear group of the illumination relay optical system, a first polarization component that directs the light from the light source to the color separation optical system, A polarization splitting optical system for splitting into a second polarization component is provided, and the projection device includes a brightness signal light valve and the second
A brightness signal relay optical system that guides a polarization component to the brightness signal light valve, and a combining optical system that combines light from the color combining optical system and light that has passed through the brightness signal light valve, The projection apparatus, wherein the color separation optical system, the color combination optical system, and the combination optical system are provided at positions where a chief ray maintains telecentricity.