JP2010181670A - Projector - Google Patents

Abstract

Provided is a projector that can adjust pixel positions with high accuracy and can be reduced in size and weight when a plurality of projected images are superimposed with a half-pixel pitch shifted.
In a projector 1, in a first optical system 4, a rotatable transparent parallel plate 45 is disposed between a light modulation device 43 and a combining optical system 6, and emitted from a color polarizer 44 by an inclination angle adjusting mechanism. The transparent parallel plate 45 is rotated at a predetermined inclination angle with respect to two axes orthogonal to the normal line of the incident surface of the light. The optical image is shifted by a half pixel pitch by a simple configuration in which the transparent parallel plate 45 is rotated by the tilt angle adjusting mechanism. The combined optical system 6 combines the optical image shifted by a half pixel pitch and the optical image emitted from the second optical system 5 to achieve high accuracy of the projected image. Further, the projector 1 can be reduced in size, weight, and cost.
[Selection] Figure 1

Description

  The present invention relates to a projector that modulates light emitted from a light source according to image information to form an optical image and project it.

In recent years, with the increase in resolution of digital images, in a projector that projects a projected image on a screen, a plurality of optical devices that form an optical image by modulating light emitted from a light source device with a light modulation element such as a light valve. And a technique for realizing high resolution and high definition of a projected image by superimposing optical images formed by the respective optical devices in a state shifted by a half pixel pitch in the vertical and horizontal directions (for example, , See Patent Document 1).
In the technique described in Patent Document 1, an optical image formed by two optical devices (projection system display modules) is enlarged and projected via a projection lens included in each optical device, and the projected image is shifted by a half pixel pitch. In this state, the projected image is increased in resolution and definition.
Here, in the technique described in Patent Document 1, since it is necessary to adjust the position of the projection image emitted from each optical device with a high accuracy of a half pixel pitch, the incident side or the reflection side of each projection lens. Are provided with a light shift element, and by adjusting the light shift amount of the light shift element, the projected images shifted by a half pixel pitch are superimposed.

JP-A-6-123868

However, in the technique described in Patent Document 1, each of the optical devices has a projection lens, and the projection images emitted from the respective projection lenses are superimposed. Therefore, there is a problem that it is difficult to superimpose the entire projected image with a half-pixel pitch shifted with high accuracy.
Further, the technique described in Patent Document 1 has a problem that it is difficult to reduce the size and weight because each optical device has a projection lens.
Furthermore, a method of combining optical images formed by a plurality of optical devices with a combining optical device and emitting it from a single projection lens is also conceivable, and a configuration is adopted in which any one of the optical devices can be adjusted in position. It is also possible.
However, when such a structure is adopted, it is possible to accurately superimpose the entire projection image due to aberrations, distortion, etc. inherent to the projection lens, but it is necessary to provide a position adjustment device for the optical device. Similarly, there is a problem that it is difficult to reduce the size and weight.

  An object of the present invention is to provide a projector capable of adjusting a pixel position with high accuracy and miniaturizing and reducing the weight when a plurality of projection images are superimposed while being shifted by a half pixel pitch. .

The projector according to the present invention is
A first optical system and a second optical system including a light modulator that modulates light emitted from the light source device according to input image information to form an optical image;
A combining optical system for combining optical images formed by the first optical system and the second optical system,
A projection optical system for projecting a composite optical image synthesized by the synthesis optical system;
A projector comprising:
In any one of the first optical system and the second optical system, a rotatable transparent parallel plate disposed between the light modulation device and the combining optical system,
The transparent parallel plate is rotated with respect to a first axis perpendicular to the normal of the incident surface of the light modulator and a second axis perpendicular to the normal and the first axis, and the normal And a tilt angle adjusting mechanism for adjusting the tilt angle of the transparent parallel flat plate.

According to such an invention, the optical image can be shifted by a half pixel pitch by a simple configuration in which a transparent parallel plate is provided at a specific position and the transparent parallel plate is rotated in a specific direction by the tilt angle adjusting mechanism. Then, the optical image shifted by the half pixel pitch and the optical image emitted from the optical system not provided with the transparent parallel plate are synthesized by the synthesis optical system, and the synthesized optical image is synthesized by the projection optical system. Since the projection is performed, the accuracy of the projected image can be increased.
Further, since the transparent parallel plate is disposed between the combining optical system and the projection optical system, the amount of deviation of the optical image can be relatively small compared to the case where the transparent parallel plate is provided on the exit side of the projection optical system. Therefore, the position adjustment of the optical image can be performed with high accuracy.
In addition, since the optical image is shifted by rotating the transparent parallel plate, it is not necessary to provide a configuration that can adjust the position of the entire optical device, so that the projector can be reduced in size, weight, and cost.

In the present invention,
The light source device includes a light source, P-polarized light parallel to an incident surface of light emitted from the light source, and a polarization separation device that separates S-polarized light perpendicular to the incident surface,
The first optical system forms an optical image based on the P-polarized light separated by the polarization separation device,
It is preferable that the second optical system forms an optical image based on the S-polarized light separated by the polarization separation device.

  According to such an invention, since the light is mainly composed of P-polarized light and S-polarized light, an optical image is formed based on the P-polarized light and S-polarized light separated by the polarization separation device, respectively. be able to. Therefore, the light use efficiency can be increased. Moreover, since light source images of two optical systems can be formed with one light source device, it is possible to reduce the size and weight.

In the present invention,
The first optical system and the second optical system are:
A color separation device that sequentially separates incident light into red light, green light, and blue light from a high wavelength region to a low wavelength region, or from a low wavelength region to a high wavelength region;
Each of the separated light components is modulated in accordance with input image information to form an optical image;
A color synthesizing optical device for synthesizing optical images of the respective color lights formed by the respective light modulation devices;
A color polarizer provided between the color synthesizing optical device and the synthesizing optical system and changing a polarization direction of the green light;
The transparent parallel plate is preferably provided on the color polarizer.

Here, when light is sequentially separated into red light, green light, and blue light from the high wavelength region to the low wavelength region, or from the low wavelength region to the high wavelength region, and an optical image is synthesized from each color light. In some cases, the polarization directions of red light and blue light are aligned with S-polarized light perpendicular to the incident surface with high reflectance, and the polarization direction of green light is P-polarized light with high transmittance.
According to such an invention, the polarization direction of green light can be aligned with the polarization direction of red light and blue light by the color polarizer. Therefore, since the polarization directions of the green light, red light, and blue light that make up the color optical image are all the same, the operability of the color optical image is easy in a composite optical system, etc., placed behind the transparent parallel plate. It is.

In the present invention,
The transparent parallel flat plate preferably has a thickness of 0.5 mm or more and 30 mm or less.

  According to such an invention, since the thickness of the transparent parallel plate is specified, the strength can be ensured and the inclination angle can be easily finely adjusted. Here, if the thickness is less than 0.5 mm, the strength may be insufficient and damage may easily occur. On the other hand, if the thickness exceeds 30 mm, even if the tilt angle of the transparent parallel plate is slightly changed, the amount of shift of the optical image becomes large, and it may be difficult to perform fine adjustment with the tilt angle adjusting mechanism. .

In the present invention,
In the tilt angle adjusting mechanism, it is preferable that the tilt angle of the transparent parallel plate with respect to the normal line is in a range of more than 0 and 5 degrees or less.

  According to such an invention, since the inclination angle is set to a specific range, the optical image can be shifted by a half pixel pitch with high accuracy. On the other hand, if the tilt angle exceeds 5 degrees, the optical image may be displaced more than the half pixel pitch.

In the present invention,
The transparent parallel flat plate is preferably made of a glass material.

  According to such an invention, the cost of a transparent parallel plate can be reduced. Examples of the glass material include quartz glass and crystallized glass.

1 is a schematic diagram illustrating a structure of a projector according to a first embodiment of the invention. The schematic diagram showing the state (A) and (B) with which the transparent parallel plate in the said embodiment is arrange | positioned. The front view which shows the inclination angle adjustment mechanism in the said embodiment. The side view which shows the inclination angle adjustment mechanism in the said embodiment. The schematic diagram showing the state of the projection image of the 1st, 2nd optical system synthesize | combined by the synthetic | combination optical system in the said embodiment. FIG. 6 is a schematic diagram illustrating a structure of a projector according to a second embodiment of the invention. The front view which shows the inclination angle adjustment mechanism in the said embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 shows a projector 1 according to an embodiment of the present invention. The projector 1 includes an illumination optical device 2, a polarization separation device 3, a first optical system 4, and a second optical system 5. , A synthesis optical system 6 and a projection optical system 7 are provided. 3 and 4, the projector 1 includes an inclination angle adjusting mechanism 9 that rotates a transparent parallel flat plate 45 described later. Although not shown, these optical elements are housed in a single housing. The projector 1 modulates the light emitted from the illumination optical device 2 in accordance with image information input by each of the first optical system 4 and the second optical system 5 to form an optical image, and combines the combined optical system 6. The optical images formed by the optical systems 4 and 5 are synthesized and the optical image synthesized by the projection optical system 7 is projected. The traveling direction of the principal ray is the Z-axis direction, and two axes that are orthogonal to the traveling direction of the principal ray are the X-axis direction (direction parallel to the paper surface) and the Y-axis direction (direction orthogonal to the paper surface). Yes.

As shown in FIG. 1, the illumination optical device 2 includes a light source device 21, a first lens array 22, a second lens array 23, and a superimposing lens 24.
The light source device 21 includes a light source lamp 211 as a light source that emits a radial light beam, and a reflector 212 that reflects the emitted light emitted from the light source lamp 211 and converges it to a predetermined position. As such a light source lamp 211, a halogen lamp, a metal halide lamp, a high-pressure mercury lamp, or the like can be used. In addition, as the reflector 212, a parabolic reflector having a rotating paraboloid as a reflecting surface or an ellipsoidal reflector reflecting a rotating ellipsoid can be employed. The light reflected by the reflector 212 is supplied to the first lens array 22.

Each of the first lens array 22 and the second lens array 23 has a configuration in which corresponding small lenses are arranged in a matrix, and the first lens array 22 converts light incident from the light source device 21 into a plurality of partial lights. The image is divided and imaged in the vicinity of the second lens array 23.
The second lens array 23 includes liquid crystal panels 42R, 42G, and 42B that constitute a first optical system 4 to be described later, and liquid crystal panels 52R and 52G that constitute the second optical system 5, together with a superimposing lens 24 that is positioned downstream of the optical path. , 52B, a plurality of partial lights divided by the first lens array 22 are superimposed. The polarization separation device 3 is disposed at the subsequent stage of the superimposing lens 24.

  The polarization separation device 3 is a plate-like body disposed at an inclination of about 45 degrees with respect to the optical path central axis of the light emitted from the illumination optical device 2, and is a dielectric on a transparent substrate such as BK7 or quartz glass. An optical element in which a multilayer film is formed. The dielectric multilayer film of the polarization separation device 3 has a function of separating random polarized light emitted from the illumination optical device 2 into two types of linearly polarized light, and is linearly polarized light parallel to the light incident surface. Transmits (P-polarized light) and reflects linearly polarized light (S-polarized light) perpendicular to the incident surface. The S-polarized light separated by the polarization separation device 3 is supplied to the first optical system 4 arranged in the direction facing the projection optical system 7, and the P-polarized light is perpendicular to the projection optical system 7. The second optical system 5 is supplied.

The first optical system 4 is a part that modulates the S-polarized light separated by the polarization separation device 3 according to image information to form an optical image. The first optical system 4 is a color separation optical device 41, a light modulation device 42, and a color composition. An optical device 43, a color polarizer 44, and a transparent parallel plate 45 are provided.
The color separation optical device 41 has a function of separating incident S-polarized light into three-color light of red light (R), green light (G), and blue light (B), and includes dichroic mirrors 411 and 412 and a reflection mirror 413. 414, 415 and phase difference plates 416, 417.

The dichroic mirrors 411 and 412 are optical elements that are arranged with an inclination of about 45 degrees with respect to the optical path center axis of the S-polarized light and in which a dielectric multilayer film is formed on a transparent substrate such as BK7 or quartz glass. The dielectric multilayer films of the dichroic mirrors 411 and 412 have a function of reflecting light in a specific wavelength region, transmitting other light, and separating S-polarized light into a plurality of color lights. The dichroic mirror 411 disposed at the front stage of the optical path reflects the blue light (B) and transmits the other red light (R) and green light (G), while the dichroic mirror 412 disposed at the rear stage of the optical path. , Green light (G) is reflected and red light (R) is transmitted. A reflection mirror 413 is disposed at the subsequent stage of the dichroic mirror 411, and reflection mirrors 414 and 415 are disposed at the subsequent stage of the dichroic mirror 412.
The reflection mirrors 413, 414, and 415 are optical elements that guide the color lights R, G, and B separated by the dichroic mirrors 411 and 412 to the light modulation device 42, and are configured by total reflection mirrors. A phase difference plate 416 is disposed downstream of the reflection mirror 413, and a wavelength phase difference plate 417 is disposed downstream of the reflection mirror 415.
The phase difference plates 416 and 417 are optical elements that change the respective color lights R and B of the S-polarized light reflected by the reflection mirrors 413 and 415 to the respective color lights R and B of the P-polarized light. Consists of a phase difference plate. The phase difference plates 416 and 417 supply the respective color lights R and B of the P-polarized light to the liquid crystal panels 42R and 42B constituting the light modulation device 42.

The light modulation device 42 includes three liquid crystal panels 42R, 42G, and 42B, three incident-side polarizing plates 421R, 421G, and 421B disposed in front of the optical paths of the liquid crystal panels 42R, 42G and 42B, and the liquid crystal panels 42R, 42G and 42B, and three exit side polarizing plates 422R, 422G, and 422B disposed in the latter stage of the optical path.
The three incident-side polarizing plates 421R, 421G, and 421B are configured by forming a polarizing film on a transparent substrate such as BK7 or quartz glass. Among these, the two incident-side polarizing plates 421R and 421B are retardation plates. It has the property of transmitting P-polarized light emitted from 416,417.
The liquid crystal panels 42R and 42B have a configuration in which a liquid crystal, which is an electro-optical material, is hermetically sealed between a pair of transparent glass substrates. The liquid crystal panels 42R and 42B are incident by controlling the alignment state of the liquid crystal according to input image information. The polarization direction of the P-polarized light emitted from the side polarizing plates 421R and 421B is modulated into S-polarized light.
Outgoing-side polarizing plates 422R and 422B transmit only S-polarized light and absorb other light out of the light emitted through the liquid crystal panels 42R and 42B. The transmitted S-polarized light is supplied to the color synthesis optical device 43.
On the other hand, the incident-side polarizing plate 421G has a property of transmitting S-polarized light separated by the polarization separation device 3, and absorbs light whose phase has been changed by the dichroic mirror 412 or the like in the middle of the optical path.
The liquid crystal panel 42G has a configuration in which a liquid crystal, which is an electro-optical material, is hermetically sealed between a pair of transparent glass substrates, and the alignment state of the liquid crystal is controlled according to input image information, so that incident-side polarization The polarization direction of the S-polarized light emitted from the plate 421G is modulated into P-polarized light.
The emission-side polarizing plate 422G transmits only P-polarized light and absorbs other light out of the light emitted through the liquid crystal panel 42G. The transmitted P-polarized light is supplied to the color synthesis optical device 43.

  The color synthesizing optical device 43 has a function of synthesizing the modulated lights emitted from the emission-side polarizing plates 422R, 422G, and 422B to form a color image, and has a substantially square shape in plan view in which four right-angle prisms are bonded. And a cross dichroic prism in which two dielectric multilayer films are formed at the interface where the right-angle prisms are bonded together. One of the two dielectric multilayer films reflects red light (R) and transmits green light (G), and the other reflects blue light (B) and transmits green light (G). These dielectric multilayer films combine red light (R), green light (G), and blue light (B) to form a color image. The formed color image is supplied to a color polarizer 44 arranged at the subsequent stage of the color synthesis optical device 43.

The color polarizer 44 is an optical element that changes the polarization direction of the blue S-polarized light and the polarization direction of the red S-polarized light formed by the first optical system 4. It is comprised by the blue change layer which changes into polarized light, and the red change layer which changes S polarized light of a red wavelength range into P polarized light. As materials for the blue color changing layer and the red color changing layer, polymer materials and inorganic materials are used. Examples of the polymer material include polyvinyl alcohol, polycarbonate, mylar, polypropylene, polystyrene, triacetate (tributyl acetate), and polymethyl methacrylate. Inorganic materials include quartz, mica, and calcite.
The green light of the P-polarized light, the red light of the P-polarized light, and the blue light of the P-polarized light are supplied to the transparent parallel plate 45 disposed at the subsequent stage of the color polarizer 44.

As shown in FIG. 2, the transparent parallel plate 45 has an incident side plane 45A and an output side plane 45B. Here, FIG. 2 illustrates a case where the optical image is shifted about the Y axis, but the same applies to the case where the optical image is shifted about the X axis. Note that the first axis described above corresponds to the Y axis orthogonal to the normal A of the incident surface, and the second axis corresponds to the X axis orthogonal to the normal A and the Y axis.
As shown in FIG. 2A, the incident-side plane 45A is inclined such that the principal ray of P-polarized light emitted from the color polarizer 44 is at an inclination angle (α) with respect to the normal A. . The inclination angle (α degree) is preferably 0 degree <α degree ≦ 10 degrees, and more preferably 0 degree ≦ α degree ≦ 5 degrees. When the tilt angle (α degree) exceeds 10 degrees, astigmatism increases and the imaging performance may not be practical. On the other hand, when the incident side plane 45A is orthogonal to the normal line A (α degree = 0 degree), the optical image is transmitted without deviation as shown in FIG.
Moreover, it is preferable that the thickness (d) of the transparent parallel flat plate 45 is 0.5 mm or more and 30 mm or less. If the thickness is less than 0.5 mm, the strength of the transparent parallel plate 45 may be insufficient and may be easily damaged. On the other hand, if the thickness exceeds 30 mm, even if the tilt angle of the transparent parallel plate 45 is slightly changed, the amount of deviation of the optical image becomes large, and it is difficult to make fine adjustments with the tilt angle adjusting mechanism 9 described later. There is a case.

  The transparent parallel flat plate 45 is preferably a glass material. Examples of the glass material include BK7, quartz glass, and crystallized glass. The glass material is preferably nd = 1.51680 and rd = 64.2.

The tilt angle adjusting mechanism 9 is a mechanism that rotates the transparent parallel flat plate 45 with respect to the Y axis and the X axis, and has a configuration in which a uniaxial goniometer stage 92 is rotatably supported on a support base 91.
The gonio stage 92 rotates the transparent parallel plate 45 about the Y axis by rotating on the support base 91. The gonio stage 92 rotates on the support base 91 by operating a rotation knob 911 around the Y axis provided on the support base 91.
The gonio stage 92 includes a lower receiving part 93 and an upper sliding part 94.
A concave surface 921 is formed on the upper end surface of the lower receiving portion 93. The concave surface 921 is a cylindrical inner peripheral surface whose cross section along the Z-axis direction serving as the principal ray axis of the projector 1 has an arc shape.
A holding frame 96 is provided above the upper sliding portion 94 via a connecting portion 95, and the transparent parallel flat plate 45 is held by the holding frame 96.
Further, the lower end surface of the upper sliding portion 94 is a convex surface 922 that follows the concave surface 921, and the convex surface 922 slides on the concave surface 921, thereby rotating the transparent parallel plate 45 about the X axis. In addition, the rotation about the X-axis allows the upper sliding portion 94 to rotate about the X-axis by operating an X-axis rotation knob 931 provided in the lower receiving portion 93.

As shown in FIG. 1, the second optical system 5 is a part that modulates the P-polarized light separated by the polarization separation device 3 in accordance with image information to form an optical image. Similar to the optical system 4, a color separation optical device 51, a light modulation device 52, a color synthesis optical device 53, and a color polarizer 54 are provided, and their functions and operations are basically the same.
The color separation optical device 51 includes dichroic mirrors 511 and 512, and reflection mirrors 513, 514, and 515. The dichroic mirror 511 disposed in the front stage of the P-polarized light path reflects red light (R). A dielectric multilayer film that transmits green light (G) and blue light (B) is formed on a transparent substrate, and a dichroic mirror 512 disposed in the subsequent stage reflects green light (G) to generate blue light. A dielectric multilayer film that transmits (B) is formed on the transparent substrate.

Similar to the first optical system 4, the light modulation device 52 includes three liquid crystal panels 52R, 52G, and 52B, and incident-side polarizing plates 521R, 521G, and 521B disposed in front of the optical paths of the liquid crystal panels 52R, 52G, and 52B. And emission-side polarizing plates 522R, 522G, and 522B disposed in the rear stage of the optical path of the liquid crystal panels 52R, 52G, and 52B. However, unlike the first optical system 4, in the second optical system 5, the retardation plates 416 and 417 and the transparent parallel plate 45 are not arranged, but the retardation plate 516 and the color polarizer 54 are arranged. Is different.
The phase difference plate 516 is disposed between the dichroic mirror 512 and the incident-side polarizing plate 521G, and changes the green P-polarized light emitted from the dichroic mirror 512 to S-polarized light, thereby changing the incident-side polarizing plate 521G. To ejaculate.
The color polarizer 54 is an optical element that changes green P-polarized light formed by the second optical system 5 to green S-polarized light, and includes a green changing layer that changes polarized light in the green wavelength region. Has been. Then, the color polarizer 54 supplies green light of S-polarized light, red light of S-polarized light, and blue light of S-polarized light to the combining optical system 6.

The combining optical system 6 combines the optical images formed by the first optical system 4 and the second optical system 5 and has a substantially square shape in plan view in which two triangular prisms are bonded together. A dielectric multilayer film is formed at the interface where the two are bonded together. This dielectric multilayer film is a polarization separation film that transmits P-polarized light and reflects S-polarized light, similarly to the polarization separation device 3 described above.
As shown in FIG. 5, the combining optical system 6 is configured so that the pixel P2 of the second optical system 5 is ½ pixel in the horizontal direction and ½ in the vertical direction with respect to the pixel P1 of the first optical system 4. The optical images of the optical systems 4 and 5 are synthesized by shifting the pixels.
Although not shown in FIG. 1, the projection optical system 7 is composed of a combination lens in which a plurality of lenses are arranged in the lens barrel with the optical axis aligned, and an optical image synthesized by the synthesis optical system 6 is projected onto the projection surface. Project to the top.

In the projector 1 according to this embodiment, in the first optical system 4, a rotatable transparent parallel plate 45 is disposed between the light modulation device 43 and the combining optical system 6, and the color is adjusted by the tilt angle adjusting mechanism 9. The transparent parallel plate 45 is rotated at a predetermined inclination angle (α) with respect to the Y axis orthogonal to the normal A of the light emitted from the polarizer 44.
Therefore, the optical image can be shifted by a half pixel pitch by a simple configuration in which the transparent parallel flat plate 45 is rotated in a specific direction by the tilt angle adjusting mechanism 9. Then, in order to synthesize the optical image shifted by the half pixel pitch and the optical image emitted from the second optical system 5 by the synthesis optical system 6 and project the synthesized optical image by the projection optical system 7. Therefore, it is possible to achieve high accuracy of the projected image.
Further, since the optical image is shifted by rotating the transparent parallel flat plate 45, it is not necessary to provide a configuration that allows the entire optical apparatus to be position-adjusted, so that the projector 1 can be reduced in size, weight, and cost.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the following description, parts that have already been described are assigned the same reference numerals and description thereof is omitted.
In the projector 1 according to the first embodiment described above, the polarization separation device 3 is provided at the subsequent stage of the illumination optical device 2, and the light emitted from the illumination optical device 2 is separated into P-polarized light and S-polarized light, and the first The optical system 4 forms an optical image based on the S-polarized light, the formed optical image is shifted by a half pixel pitch, the second optical system 5 forms an optical image based on the P-polarized light, and each optical image is A synthesized image was synthesized by the synthesis optical system 6 to form a projection image.
In contrast, in the projector 8 according to the second embodiment, as shown in FIG. 6, the illumination optical device 2 is provided in each of the first optical system 4 and the second optical system 5, and Based on the emitted light, each of the first optical system 4 and the second optical system 5 forms an optical image. The first optical system 4 shifts the formed optical image by a half pixel pitch, and the combining optical system 6 The difference is that optical images are combined to form a projected image.
In the projector 1 according to the first embodiment described above, the optical image formed by the first optical system 4 is shifted by a half pixel pitch by the tilt angle adjusting mechanism 9.
On the other hand, as shown in FIG. 7, the projector 8 according to the second embodiment is different in that the optical image is shifted by a half-pixel pitch around the X axis and the Y axis by the tilt angle adjusting mechanism 9A.
In FIG. 7, the optical image emitted from the color polarizer 44 is transmitted through the transparent parallel plate 45 from the back side to the front side of the drawing.

Polarization conversion elements 81 and 82 are provided between the third lens array 23 and the superimposing lens 24 of each illumination optical device 2. The polarization conversion elements 81 and 82 are provided to convert the light emitted from the illumination optical device 2 into approximately one type of linearly polarized light, and the polarization conversion element 81 of the first optical system 4 includes illumination optics. The light emitted from the device 2 is converted into S-polarized light. On the other hand, the polarization conversion element 82 of the second optical system 5 converts the light emitted from the illumination optical device 2 into P-polarized light.
The polarization conversion elements 81 and 82 are plate-like bodies formed by joining a plurality of prisms having a parallelogram cross section with one diagonal being 45 degrees and the other diagonal being approximately 135 degrees. In addition, polarization separation films and total reflection mirrors are alternately deposited on the bonded interface.
In addition, a plurality of half-wave retardation plates are provided on the light exit surfaces of the polarization conversion elements 81 and 82 at a predetermined pitch.

In such polarization conversion elements 81 and 82, when light is incident on the surface on which the polarization separation film is formed, the P-polarized light is transmitted and emitted as it is, and the S-polarized light is bent at a substantially right angle by the polarization separation film. Then, it is again bent at a right angle by the total reflection mirror and emitted.
The emitted P-polarized light or S-polarized light has its polarization direction converted by 90 degrees by a half-wave retardation plate provided at the subsequent stage, thereby converting the incident light into one kind of linearly polarized light. It becomes possible to do. The polarization conversion element 81 is provided at a position where the half-wave retardation plate corresponds to the polarization separation film, and the polarization conversion element 82 is provided at a position where the half-wave retardation plate corresponds to the total reflection mirror. It has been.

As shown in FIG. 7, the tilt angle adjusting mechanism 9A has a structure in which a frame 92A is rotatably supported on a support base 91A, and a holding frame 95A is rotatably supported with respect to the frame 92A. is there.
The frame body 92A supported on the support base 91A is rotatable about the Y axis, and the transparent parallel flat plate 45 can be rotated about the Y axis by rotating the frame body 92A. Note that the rotation of the frame 92A is performed by the Y axis rotation adjustment knob 911A provided on the support base 91A, as in the first embodiment.
The frame body 92A is made of a substantially U-shaped metal body when viewed from the front. A hole 931A is formed on one end of the U-shaped upper portion on the side surface facing the U-shape, and a penetrating hole is formed on the other end. A hole 932A is formed.
The holding frame 95A accommodates and holds the transparent parallel flat plate 45 inside the rectangular frame, and rotary couplings 941A are provided at both ends of the substantially central ends that face each other in the rectangular horizontal direction.
The rotary connector 941A is inserted into the hole 931A, the other rotary connector 941A is inserted into the through hole 932A, and the transparent parallel flat plate is rotated by the X axis rotation adjustment knob 943B attached to the through hole 932A from the outside of the frame 92A. 45 can be rotated and adjusted with respect to the X axis.

In the projector 8 according to the second embodiment, in addition to the effects of the projector 1 according to the first embodiment described above, the illumination optical device 2 that supplies light to the optical systems 4 and 5 is provided independently. Therefore, a large amount of light of the optical image formed by each of the optical systems 4 and 5 can be secured, and the brightness of the projected image can be increased.
Further, by independently controlling the driving of each illumination optical device 2, the amount of light emitted from each illumination optical device 2 can be adjusted, so that the brightness of the projection image synthesized by the synthesis optical system 6 can be adjusted. Unevenness, color unevenness, etc. can be further reduced.

  Further, since the projector 8 is a gimbal type, the center of rotation in the X-axis direction and the center of the transparent parallel plate 45 always coincide. Accordingly, since the transparent parallel flat plate 45 can be rotated according to the rotation angle of the rotary coupler 941A, the second inclination angle adjustment mechanism 9A has a ZX rotation as compared with the inclination angle adjustment mechanism 9 having a so-called gonio stage. The transparent parallel plate 45 can be easily rotated with a relatively small amount of rotation of the coupler 941A.

[Modification of Embodiment]
In addition, this invention is not limited to embodiment mentioned above, The deformation | transformation as shown below is also included.
In the above-described embodiment, the transmissive liquid crystal panels 42R, 42G, 42B, 52R, 52G, and 52B are employed as the light modulation device. However, the present invention is not limited to this, and for example, a reflective liquid crystal panel or a micromirror The present invention may be adopted in a projector that composes two optical systems with a device using the, and combines them to project a projected image.
In addition, the specific structure, shape, and the like in the implementation of the present invention may be other structures as long as the object of the present invention can be achieved.

  The present invention can be used for a projector including a plurality of color synthesis optical systems such as a so-called 6LCD type projector.

DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Illumination optical apparatus, 3 ... Polarization separation apparatus, 4 ... 1st optical system, 5 ... 2nd optical system, 6 ... Synthesis optical system, 7 ... Projection optical system, 8 ... Projector, 21 ... Light source device 22 ... first lens array, 23 ... second lens array, 24 ... superimposing lens, 41 ... color separation optical device, 42 ... light modulation device, 42R, 42G, 42B ... liquid crystal panel, 43 ... color synthesis optical device, 44 ... Color polarizer, 45 ... Transparent parallel plate, 51 ... Color separation optical device, 52 ... Light modulation device, 52R, 52G, 52B ... Liquid crystal panel, 53 ... Color synthesis optical device, 54 ... Color polarizer, 81, 82 ... Polarization conversion element 211 ... light source lamp 212 ... reflector 411, 412 ... dichroic mirror, 413, 414, 415 ... reflection mirror, 421R, 421G, 421B ... incident side polarizing plate, 42 R, 422G, 422B: Emission side polarizing plate, 511, 512 ... Dichroic mirror, 513, 514, 515 ... Reflection mirror, 521R, 521G, 521B ... Incident side polarizing plate, 522R, 522G, 522B ... Emission side polarizing plate, P1 ... Pixel, P2 ... Pixel, 9, 9A ... Inclination angle adjustment mechanism, 91, 91A ... Support base, 92 ... Gonio stage, 92A ... Frame, 93 ... Lower receiving part, 94 ... Upper sliding part, 94A ... Rotating connection 95, connecting portion, 95A, 96 ... holding frame, 921 ... concave surface, 922 ... convex surface, 931A ... hole, 932A ... through hole, 941A ... rotary connector

Claims (6)

A first optical system and a second optical system including a light modulator that modulates light emitted from the light source device according to input image information to form an optical image;
A combining optical system for combining optical images formed by the first optical system and the second optical system,
A projection optical system for projecting a composite optical image synthesized by the synthesis optical system;
A projector comprising:
In any one of the first optical system and the second optical system, a rotatable transparent parallel plate disposed between the light modulation device and the combining optical system,
The transparent parallel plate is rotated with respect to a first axis perpendicular to the normal of the incident surface of the light modulator and a second axis perpendicular to the normal and the first axis, and the normal And a tilt angle adjusting mechanism for adjusting the tilt angle of the transparent parallel plate with respect to the projector. The projector according to claim 1.
The light source device includes a light source, P-polarized light parallel to an incident surface of light emitted from the light source, and a polarization separation device that separates S-polarized light perpendicular to the incident surface,
The first optical system forms an optical image based on the P-polarized light separated by the polarization separation device,
The second optical system forms an optical image based on S-polarized light separated by the polarization separation device. The projector according to claim 1 or 2,
The first optical system and the second optical system are:
A color separation device that sequentially separates incident light into red light, green light, and blue light from a high wavelength region to a low wavelength region, or from a low wavelength region to a high wavelength region;
Each of the separated light components is modulated in accordance with input image information to form an optical image;
A color synthesizing optical device for synthesizing optical images of the respective color lights formed by the respective light modulation devices;
A color polarizer provided between the color synthesizing optical device and the synthesizing optical system and changing a polarization direction of the green light;
The transparent parallel flat plate is provided in the color polarizer. The projector according to any one of claims 1 to 3,
The transparent parallel flat plate has a thickness of 0.5 mm or more and 30 mm or less. The projector according to any one of claims 1 to 4,
The tilt angle adjusting mechanism has a tilt angle of the transparent parallel plate with respect to the normal line in a range of greater than 0 and 5 degrees or less. The projector according to any one of claims 1 to 5,
The transparent parallel flat plate is made of a glass material.

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