JP4788275B2 - Projection-type image display device - Google Patents

Description

  The present invention relates to a projection apparatus that projects an image on a screen using an image display element, for example, an optical unit such as a liquid crystal projector apparatus, a reflective image display projector apparatus, a projection type rear projection television, or a projection type image display. The present invention relates to an apparatus and relates to a technique for scrolling color light separated by a color separation optical system onto an image display element.

  Conventionally, light from a white light source is passed through an integrator, a polarization beam splitter (hereinafter referred to as “PBS”), and a collimator lens, and then a plurality of color separation surfaces (hereinafter referred to as “dichroic mirrors”) are used. Then, the light is separated into red light (hereinafter referred to as “R light”), blue light (hereinafter referred to as “B light”), and green light (hereinafter referred to as “G light”), and each separated color light is respectively rotated using a rotating polyhedron. By changing the optical path direction, each color light is simultaneously irradiated in a rectangular shape (band) at different locations on the image display element, and the locations irradiated with each color light are sequentially moved in a certain direction on the image display element ( In the following, a single-plate projection type image display device that is referred to as a “scroll” is known. This type of projection-type image display device is described in, for example, Japanese Patent Application Laid-Open Nos. 2004-170549 and 2003-149738.

  In Japanese Patent Application Laid-Open No. 2004-170549, as shown in FIGS. 1 and 3, a rotating polyhedron is disposed in each optical path of light separated into three colors, and the rotation of the rotating polyhedron causes an image display element to move on. A rectangular irradiation area of each color is scrolled. Further, in Japanese Patent Laid-Open No. 2003-149738, as shown in FIG. 1, a strip-shaped three-color light is formed adjacent to each other using a color prism provided with a dichroic mirror, and one lens array wheel is rotated. By driving, a rectangular irradiation area of each color irradiated on the video display element is scrolled.

JP 2004-170549 A JP 2003-149738 A

  In the technique disclosed in Japanese Patent Application Laid-Open No. 2004-170549, a plurality of rotating polyhedrons are arranged for each color that has been color-separated, and thus there are problems that the number of parts is large and it is difficult to reduce the size and weight. In addition, it is necessary to control the rotation of the three rotating polyhedrons with high accuracy so that the three color rectangular illumination areas are located at different positions on the image display element.

  In the technique of Japanese Patent Laid-Open No. 2003-149738, as estimated from FIG. 1, the size of each lens constituting the lens array wheel is comparable to that of a liquid crystal display element. In addition, there is a problem that it becomes heavy and it is difficult to reduce the size and weight.

  In the technique disclosed in Japanese Patent Laid-Open No. 2003-149738, a color separation unit (in the literature, a color separator) provided on a surface (hereinafter referred to as an emission side) of a light beam of a rod integrator (rod prism in the literature) is emitted. ) Is provided. In this color separation unit, light in a specific wavelength band (B in the literature) is obtained by a dichroic mirror disposed at an angle of 45 degrees with respect to a surface on which the light beam of the color separation unit is incident (hereinafter referred to as an incident side surface). Color separation is performed by transmitting light) and reflecting light (R light and G light) in other wavelength bands by changing the direction by 90 degrees.

  By the way, generally, in an illumination optical system, a spatial spread in which a light beam that can be effectively handled exists can be expressed as a product of an area and a solid angle (Eometric: Extent). The product of the area and the solid angle is stored in the optical system.

  Here, when considering the light beam incident on the rod integrator from the light source, the substantially white light beam incident on the rod integrator is condensed on the incident side surface of the rod integrator disposed in the vicinity of the second focal position of the reflector. Since the condensing area of the incident light beam is small, the solid angle of the incident light beam is increased. That is, the angle of incident light with respect to the optical axis increases. Since the angle of the incident light beam is almost preserved by the rod integrator, the light beam incident on the dichroic mirror in the color separation unit from the rod integrator has a large solid angle.

  FIG. 3A schematically shows a dichroic mirror and a light beam in the color separation unit. As shown in FIG. 3A, the incident angle of the optical axis is 45 degrees, but the incident light beam also has a solid angle. When this solid angle is θ, the incident angle of the incident light beam is in the range of 45 ° ± θ. That is, the incident angle on the dichroic mirror is changed from (45 degrees -θ) to (45 degrees + θ), and a light flux in the angle range 2θ enters. Since the dichroic mirror has an incident angle characteristic, the total wavelength separation characteristic for the entire light beam of the dichroic mirror is as shown in FIG. 3 (2), and the change (slope) of the transmittance with respect to the wavelength does not become steep. As a result, the wavelength separation characteristics deteriorate. For example, considering a blue light transmitting dichroic mirror, the separation characteristics of B light and G light deteriorate at a specified wavelength, and a part of the B light is mixed with the G light. Conversely, a part of the G light is converted into the B light. The problem of color mixing occurs.

  In Japanese Patent Application Laid-Open No. 2004-170549, a dichroic mirror is used as the color separation means and is arranged at 45 degrees with respect to the optical axis. However, as shown in FIG. 1, since the lens array is used as the integrator means for uniformizing the light amount distribution, the area of the light beam incident on the dichroic mirror is large, and the solid angle is obtained by the etendue described above. Get smaller. Therefore, since the range of the incident angle of the light beam to the dichroic mirror is small, there is almost no deterioration of the wavelength separation characteristic.

  The present invention has been made in view of the above-described circumstances, and in a projection-type image display apparatus using a rod integrator, it is possible to reduce the size and weight, or to improve color separation characteristics, or to reduce color mixing. For the purpose.

  In one embodiment of the present invention, a reflective surface is provided in a region other than the opening inside the entrance aperture plate of the rod integrator. Further, the first and second polarization separation prisms having the same polarization characteristics that, for example, reflect light in the first polarization direction and transmit light in the second polarization direction are arranged in the longitudinal direction on the exit side of the rod integrator. A quarter-wave plate is provided on the side surface of the first and second polarization separation prisms on the rod integrator side. For the second polarization separation prism, a total reflection plate is further provided outside the quarter wave plate, and a dichroic mirror is provided on the side surface opposite to the rod integrator.

  With such a configuration, the light reflected by the dichroic mirror in contact with the first polarization separation prism is reflected by the reflection surface on the inner surface of the incident aperture plate, and is a quarter wavelength between the first polarization separation prism and the rod integrator. Polarized light is converted by the plate. The light in the first polarization direction reflected by the first polarization separation prism is incident on the second polarization separation prism and further reflects the light in the first polarization direction reflected by the second polarization separation prism. Reflected by the total reflection plate. Therefore, the light in the first polarization direction passes through the quarter wavelength plate twice, and the polarized light is converted.

  It is possible to provide a projection-type image display device that is small and light and has excellent color separation performance and little color mixing.

Hereinafter, the best mode of the present invention will be described with reference to the drawings.
In each figure, elements having common functions are denoted by the same reference numerals, and description of elements once described is omitted.

  Hereinafter, a color separation unit according to the first embodiment and a projection-type image display device that includes the color separation unit and uses one rotating polyhedron will be described with reference to FIGS. 1 and 2. In order to facilitate the following illustration, a right-handed rectangular coordinate system is introduced in FIG. That is, the optical axis direction of the light source unit 1 is the Z axis, the direction orthogonal to the paper surface of FIG. 2, the direction from the back of the paper surface to the paper surface is the Y axis, and the axis orthogonal to the YZ plane formed by the YZ axis is the X axis.

  FIG. 1 is a configuration diagram of a color separation unit which is a main part of the first embodiment, and FIG. 2 is a configuration diagram of a projection type video display apparatus according to the first embodiment.

  First, a projection-type image display device equipped with Example 1 will be described with reference to FIG. In FIG. 2, the substantially white light beam emitted from the light source unit 1 having the light source 11 and the reflector 12 (in this figure, the elliptical reflector) is incident on the incident side surface of the color separation unit 2 a disposed in the vicinity of the second focal position of the reflector 12. And is incident on the color separation unit 2a. The color separation unit 2a includes an incident aperture plate 22, a rod integrator 24, a quarter wavelength plate 23, a polarization conversion element 21, and a dichroic mirror 26 in order from the incident side, and the polarization direction of light from the light source unit 11 is set to a predetermined direction. Align. The color separation unit 2a performs color separation into three strip-shaped color lights (color bars), details of which will be described later.

The light flux (color bar) emitted from the color separation unit 2a is improved in the purity of the polarization state by the polarizing plate 81 that transmits polarized light in a predetermined direction via the reduction optical system 31 and the optical path bending mirror 32, and is supplied to the first PBS 51. Incident. Here, the polarization direction of the light beam incident on the first PBS 51 is a direction (S-polarized light) perpendicular to the incident surface (surface formed by incident light and reflected light: ZX surface). Therefore, the polarization direction transmitted by the polarizing plate 81 is S-polarized light. The S-polarized light beam (color bar) incident on the first PBS 51 is reflected by the polarization separation surface S51 and travels toward the rotating polyhedron 4. The S-polarized light beam emitted from the first PBS 51 passes through the quarter-wave plate 82 and is converted into circularly polarized light. The rotating polyhedron passes through the enlargement / reduction optical system 33 (which functions as a reduction optical system here). 4 is incident. In this process, the color bar emitted from the color separation unit 2a is mapped to the space before the rotating polyhedron 4 by the reduction optical system 31 and the enlargement / reduction optical system 33 to form an aerial image (not shown). .

  The aerial image is reflected by the reflecting surface 41 on the surface of the rotating polyhedron 4 and turns the optical path. By passing through the quarter-wave plate 82 again, the circularly polarized light is converted to P-polarized light, so that it passes through the polarization separation surface S51 of the first PBS 51 this time. The light beam transmitted through the first PBS 51 is converted into S-polarized light by the half-wave plate 83. Then, the S-polarized light beam incident on the second PBS 52 is reflected by the polarization separation surface S52 and enters the video display element 6. In this process, the aerial image formed in the space in front of the rotating polyhedron 4 forms a mirror image (not shown) on the reflecting surface 41 of the rotating polyhedron 4, and the mirror image is reduced / enlarged optical system 33 (here Then, the image is enlarged and mapped onto the image display element 6.

  Here, the optical system incident on the rotating polyhedron 4 is described as a reduction optical system, and the optical system exiting the rotating polyhedron 4 is described as an enlargement optical system. There is no problem in terms of mapping even if the optical system and the optical system exiting from the rotating polyhedron 4 are reduced optical systems. However, in this case, the aerial image formed in the vicinity of the reflecting surface 41 of the rotating polyhedron 4 becomes large, and as a result, the rotating polyhedron 4 becomes large. Therefore, it is advantageous in terms of reduction in size and weight when the optical system incident on the rotating polyhedron 4 is a reduction optical system and the optical system emitting the rotating polyhedron 4 is an enlargement optical system.

  The light beam reflected by each pixel of the image display element 6 is converted into P-polarized light when each pixel is ON, so this time, it passes through the second PBS 52 and is screened by the projection lens 7 (not shown). The projection is enlarged. When each pixel is OFF, the polarization state remains S-polarized light, so that it is reflected again by the polarization plane of the second PBS 52, and the light beam is not enlarged and projected on a screen or the like. Reference numeral 84 denotes a polarizing plate that transmits P-polarized light.

  Here, the outline of the scroll action by the rotating polyhedron 4 will be described below. When an object (aerial image) is placed in front of the reflecting surface 41, a mirror image (not shown) is formed on the back side of the reflecting surface 41 at the same distance as the distance from the reflecting surface 41 to the object. By the way, since the reflecting surface 41 is disposed on the surface of the rotating polyhedron 4, the angle of the reflecting surface 41 is changed by the rotation of the rotating polyhedron 4. For example, when the reflecting surface 41 rotates by an angle θ, the reflected light changes by an angle 2θ by a multiple of the angle. At this time, the reflected light overlaps with the emitted light as if it were emitted from different positions in the specular image. Therefore, if the angle of the reflection surface 41 is continuously changed, continuous light rays are emitted from different positions of the specular image. That is, light scrolling can be realized by changing the angle of the reflecting surface 41.

  Next, the color separation unit 2a will be described in detail with reference to FIG.

  As shown in FIG. 1, the color separation unit 2 a has, in order from the incident side, an incident aperture plate 22 having a total reflection surface 222 in an inner surface area other than the incident aperture 221 having an optical incident aperture 221, and a cross section is substantially A rod integrator 24 that has a prismatic structure composed of a rectangular optically transparent member (for example, a glass member), uniformizes the light amount distribution, a quarter-wave plate 23, a total reflection mirror 213, and a rod A polarization conversion element 21 that aligns the polarization direction of the light beam from the integrator 24 with a predetermined polarization direction, and a dichroic mirror 26 that is a color separation element. The quarter wavelength plate 23 may be composed of one first polarization separation prism 211 and second polarization separation prism 212, or one quarter wavelength plate may be provided for each prism. . Here, in the color separation unit 2a, since the incident surface of the polarization conversion element 21 (the surface formed by the incident light and the reflected light) is the YZ surface, the light whose polarization direction is perpendicular to the YZ surface is S-polarized light, Parallel light becomes P-polarized light. That is, the P-polarized light (parallel to the XZ plane) in FIG. 2 becomes S-polarized light in FIG. A light beam, which is substantially white natural light that has entered the optical entrance aperture 221 of the entrance aperture plate 22 from the light source unit 1, enters the rod integrator 24. The incident light is repeatedly reflected on the side surface of the rod integrator 24 to make the light quantity distribution uniform. The light that has passed through the rod integrator 24 passes through the quarter-wave plate 23, but is natural light and remains natural light even after being transmitted. The light beam that has passed through the quarter-wave plate 23 enters the polarization conversion element 21, and the polarization state thereof is aligned with a predetermined polarization state (here, P-polarized light). Hereinafter, the polarization conversion element 21 will be described in detail.

  The polarization conversion element 21 has a first polarization separation prism 211 and a second polarization separation prism 212 arranged in the Y-axis direction. The first polarization separation prism 211 is disposed on the side from which the light beam is emitted from the rod integrator 24, and the second polarization separation prism 212 is disposed on the −Y side (lower side in FIG. 1) of the first polarization separation prism 211. . In addition, the polarization separation surfaces S211 and S212 are arranged to be orthogonal to each other.

The dichroic mirror 26 is disposed in contact with the emission side surface S21 of the polarization conversion element, and transmits blue light only to the central region obtained by dividing the emission side surface S21 into approximately three parts in the Y-axis direction and reflects other color lights. A red transmissive dichroic mirror 261 is disposed on the + Y side to transmit only R light and reflects other color light, and a green transmissive dichroic that transmits only G light and reflects other color light on the -Y side. A mirror 263 is arranged. Here, in the dichroic mirror 26, a region in contact with the first polarization separation prism 211 is a first dichroic mirror region 264, and a region in contact with the second polarization separation prism 211 is a second dichroic mirror region 265.

  Of the white light incident on the polarization conversion element 21 from the rod integrator 24, the P-polarized light beam passes through the first polarization separation surface S211 and reaches the first dichroic mirror region 264 disposed in contact with the emission side surface. . Here, the R light reaching the red transmitting dichroic mirror 261 and the B light reaching the blue transmitting dichroic mirror 262 are transmitted.

  On the other hand, of the white light incident on the polarization conversion element 21, the S-polarized light beam reflects the first polarization separation surface S211, enters the second polarization separation prism 212, reflects on the second polarization separation surface S212, and travels. The direction is changed to the -Z direction, transmitted through the quarter-wave plate 23, reflected by the total reflection mirror 213, and again transmitted through the quarter-wave plate 23, so that the S-polarized light is converted into the P-polarized light. The light passes through the polarization separation surface S212 and reaches the second dichroic mirror region 265. Here, the B light reaching the blue transmitting dichroic mirror 262 and the G light reaching the green transmitting dichroic mirror 263 are transmitted.

Next, the light flux that does not pass through the dichroic mirror 26 will be described. Light flux other than R light (G light and B light) that has reached the red transmissive dichroic mirror 261 that does not pass through the first dichroic mirror region, and light flux other than B light (R light and G light) that has reached the blue transmissive dichroic mirror 262 Since the reflected light beam is P-polarized light, it passes through the first polarization separation surface S211, passes through the quarter-wave plate 23, passes through the rod integrator 24, and reaches the entrance aperture plate 22. The light beam reaching the total reflection surface 222 of the incident aperture plate 22 is reflected, passes through the rod integrator 24 again, passes through the quarter-wave plate 23, and enters the polarization conversion element 21. At this time, for transmitting twice 1/4-wave plate 23 in a reciprocating, the light beam was P-polarized light becomes S polarized light, then, proceeds the same path as the S-polarized light of the white light incident on the polarization conversion element 21 described above The second dichroic mirror region 265 is reached.

  On the other hand, a light beam other than B light (R light and G light) that has not reached the second dichroic mirror region 265 and has reached the blue transmission dichroic mirror 262 and a light beam other than G light (R light) that has reached the green transmission dichroic mirror 263. Since the reflected light beam is P-polarized light, it is transmitted through the second polarization separation surface S212, transmitted through the quarter-wave plate 23, reflected by the total reflection mirror 213, and again 1 / The light passes through the four-wave plate 23 and enters the second polarization separation prism 212. At this time, the P-polarized light is converted to S-polarized light since it has been transmitted through the quarter-wave plate 23 twice, is reflected by the second polarization separation surface S212, is incident on the first polarization separation prism 211, and is separated by the first polarization separation. The light is reflected again by the surface S211, passes through the quarter-wave plate 23, passes through the rod integrator 24, and reaches the incident aperture plate 22. The light beam reaching the total reflection surface 222 of the incident aperture plate 22 is reflected, passes through the rod integrator 24 again, passes through the quarter-wave plate 23, and enters the polarization conversion element 21. At this time, since the light passes through the quarter-wave plate 23 twice, the light beam that has been S-polarized light becomes P-polarized light, and then proceeds along the same path as the P-polarized light incident on the polarization conversion element 21 described above. One dichroic mirror area 264 is reached.

  That is, the light beam that has not passed through the dichroic mirror 26 returns to the incident aperture plate 22, is reflected by the total reflection surface 222 of the incident aperture plate 22, and enters the dichroic mirror 26 again. At this time, by passing through the quarter-wave plate 23 twice, the polarization state is switched between P-polarized light and S-polarized light, and the previously described color separation action for P-polarized light and S-polarized light is repeated. That is, the light beam reflected by the first dichroic mirror region 264 returns to the incident aperture plate 22, is reflected by the total reflection surface 222, and enters the second dichroic mirror region 265. Conversely, the light beam reflected by the second dichroic mirror region 265 returns to the incident aperture plate 22, is reflected by the total reflection surface 222, and enters the first dichroic mirror region 264. In this way, the dichroic mirror regions 264 and 265 that re-enter the light are alternately inverted, and the color is separated through the predetermined dichroic mirror during this time.

  Specifically, the G light and B light reflected by the red transmissive dichroic mirror 261 in the first dichroic mirror region 264, and the R light and G light reflected by the blue transmissive dichroic mirror 262 return to the incident aperture plate 22, The light is reflected by the total reflection surface 222 and reaches the second dichroic mirror region 265 side. Here, the blue transmissive dichroic mirror 262 transmits B light and reflects R and G light, and the green transmissive dichroic mirror 263 transmits G light and reflects R and B light. Here, the reflected light beam returns to the incident aperture plate 22 again, is reflected by the total reflection surface 222, and reaches the first dichroic mirror region 264 this time. Here, in the red transmission dichroic mirror 261, R light is transmitted and G light and B light are reflected, and in the blue transmission dichroic mirror 262, B light is transmitted and R light and G light are reflected. As described above, the beam returns to the same first dichroic mirror region 264 in two round trips. However, since the light beam incident on the dichroic mirror 26 has a certain angle, the first incident point coincides with the incident point after two round trips. Most of the light flux exits the dichroic mirror 26 while repeating the reciprocation several times.

  A part of the light flux returned to the incident aperture plate 22 passes through the incident aperture 221 to the light source unit 1 side.

  The light beam emitted from the color separation unit 2a is P-polarized light, which is S-polarized light in FIG. 2 as described above. With the above configuration, the size and weight can be reduced.

Further, the rod integrator 24 does not have a structure in which the inside is made of a transparent member as shown in FIG. 1, but has a hollow structure, and a structure in which a reflection mirror is formed on the inner surface of the rod integrator 24 may be used. . FIG. 5 shows a diagram in which the rod integrator is constituted by a mirror. A reflection mirror 501 is arranged on the inner surface of the rod integrator 500, and the light incident on the rod integrator 500 travels through the rod integrator 500 while repeating total reflection by the reflection mirror 501 , and uniformizes the light quantity distribution. I do. Needless to say, the other operations are the same as those in FIG.

  Next, specific effects of the color separation unit according to this embodiment will be described.

  FIG. 4 is a graph showing the relationship between the incident light angle and the wavelength separation characteristic with respect to the dichroic mirror of the first embodiment.

  As shown in FIG. 4A, when a light beam having an incident angle θ is incident on a vertically arranged dichroic mirror, the light beam enters from a range of ± θ with respect to the normal line of the color separation surface. Accordingly, the incident angle on the dichroic mirror is changed from 0 degrees to θ, and a light flux in the angle range θ is incident. Therefore, the total wavelength separation characteristic for the entire light beam of the dichroic mirror is as shown in FIG. 4 (2), and the change (slope) of the transmittance with respect to the wavelength can be abrupt, the wavelength separation characteristic becomes good, and after the separation. The color purity of a single color is improved.

The areas of the red light transmissive dichroic mirror 261, the blue light transmissive dichroic mirror 262, and the green light transmissive dichroic mirror 263 are substantially the same, but the areas of at least one color light transmissive dichroic mirror may be different. .
For example, as shown in FIG. 6, the area of the blue light transmitting dichroic mirror 302 is made larger than that of the red light transmitting dichroic mirror 301 and the green light transmitting dichroic mirror 303. Thus, by adjusting the area of at least one color light transmitting dichroic mirror, it is possible to adjust brightness and color.

  Further, as shown in FIG. 7, in addition to the red light transmissive dichroic mirror 401, the blue light transmissive dichroic mirror 402, and the green light transmissive dichroic mirror 403, a white light transmissive dichroic mirror 404 that transmits white light may be provided. By providing the white light transmitting dichroic mirror 404 in this way, a bright projection image can be obtained by the white light transmitted through the white light transmitting dichroic mirror 404. Further, the arrangement of the regions of the dichroic mirror is not limited to that shown in the drawing.

  As described above, it is possible to realize a projection-type image display apparatus that can be reduced in size and weight and has good color separation characteristics.

  FIG. 8 is a block diagram of a color separation unit 2d showing a second embodiment according to the present invention.

As shown in the figure, the rod integrator 600 has a prismatic shape in which the area of the incident side surface S1 is smaller than the area of the outgoing side surface S2. Similar to the first embodiment described above, the light distribution is made uniform by the rod integrator 600, the polarized light is aligned with the P-polarized light by the polarization conversion element, and the colors are separated by the dichroic mirror 26. Here, the rod integrator 600 since the area of the entrance surface S1 is a prismatic shape having a smaller such a shape than the exit surface S2, the light incident from the incident side surface S1 is, by repeating the reflections, the angle becomes smaller Injected from the exit side S2. As a result, the angle of the light beam incident on the dichroic mirror 26 can be reduced, the color separation performance is improved, and the polarization conversion characteristics of the PBS and the image display element arranged in the subsequent stage are improved to increase the contrast. Can be realized.

  FIG. 9 is a block diagram of an illumination apparatus showing a third embodiment according to the present invention.

In the embodiment described above, the polarization conversion element 21 and the dichroic mirror 26 are fixedly disposed in contact with each other.
However, the present invention is not limited to this, and the same effect can be obtained even when the air layer 700 is provided between the polarization conversion element 21 and the dichroic mirror 26 as shown in FIG.

Also, with the above configuration, for example, in the case of a model that emphasizes brightness, as shown in FIG. 7, a dichroic mirror 400 provided with a white transmissive dichroic mirror is attached, and light in a specific wavelength region is efficiently used. In the case of a model that is frequently used and places importance on color reproducibility, a dichroic mirror 300 with different areas of at least one color light transmitting dichroic mirror is mounted as shown in FIG. Thus, by replacing only the dichroic mirror, it becomes possible to deal with projection-type video display devices having various performances. If the air layer has a large thickness, light that cannot be captured by the dichroic mirror 26 is generated. Therefore, the air layer 700 should be thin.

  In the above embodiment, only the method of arranging RGB one by one has been shown, but the same effect can be obtained even if two colors are arranged symmetrically with respect to the X axis, for example. Needless to say.

It is a block diagram of the color separation unit in the first embodiment. It is a block diagram of the projection type video display apparatus which shows a 1st Example. It is a figure explaining the incident angle and color separation characteristic to the dichroic mirror in the conventional apparatus. It is a figure explaining the incident angle and color separation characteristic to the dichroic mirror in a present Example. It is a block diagram of the color separation unit using a hollow rod integrator. It is a figure which shows another structural example of a dichroic mirror. It is a figure which shows another structural example of a dichroic mirror. It is a block diagram of the color separation unit in a 2nd Example. It is a block diagram of the color separation unit in a 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light source unit, 11 ... Light source, 12 ... Reflector, 2a, 2b, 2c, 2d ... Color separation unit, 21 ... Polarization conversion element, 211 ... 1st polarization separation prism, 212 ... 2nd polarization separation prism, 213 ... All Reflection mirror, 22 ... incident aperture plate, 221 ... incident aperture, 222 ... total reflection surface, 23 ... quarter wave plate, 24 ... rod integrator, 26 ... dichroic mirror, 261 ... red transmissive dichroic mirror, 262 ... blue transmissive dichroic 263 ... Green transmissive dichroic mirror, 264 ... first dichroic mirror region, 265 ... second dichroic mirror region, 31 ... reduction optical system, 32 ... optical path folding mirror, 33 ... enlargement / reduction optical system, 4 ... rotation polyhedron, 51 ... 1st PBS, 52 ... 2nd PBS, 6 ... Image display element, 7 ... Projection lens, 8 ... polarizing plate, 82 ... 1/4-wave plate, 83 ... 1/2-wave plate, 84 ... polarizing plate, 300 ... dichroic mirror, 301 ... red transmission dichroic mirror, 302 ... the blue transmission dichroic mirror, 303 ... green transmission dichroic mirror , 400 ... Dichroic mirror, 401 ... Red transmission dichroic mirror, 402 ... Blue transmission dichroic mirror, 403 ... Green transmission dichroic mirror, 404 ... White transmission dichroic mirror, 500 ... Rod integrator, 501 ... Reflection mirror , 600 ... Rod integrator, 700 ... the air layer .

Claims (8)

A white light source,
An image display element that forms an optical image according to an image signal from the light emitted from the white light source;
A color separation unit that separates a visible light beam emitted from the white light source into a plurality of color bars;
Scroll means for moving each of the color bars of the plurality of colors emitted from the color separation unit on the video display element;
A first mapping optical system for mapping the plurality of color bars in the vicinity of the scroll means;
A second mapping optical system for mapping the color bars of the plurality of colors scrolled by the scroll means onto the video display element;
A projection device that projects light emitted from the image display element as a color image;
The color separation unit is
An incident aperture plate in which an opening for receiving light from the white light source is formed, and a reflection surface is formed in a region other than the opening on the inner surface;
A rod integrator that equalizes the light distribution;
The first polarization separation surface that transmits the light in the first polarization direction in the light emitted from the rod integrator, emits the light from the first side surface, and reflects the light in the second polarization direction in the second side surface direction. A first polarization separation prism having:
A first quarter-wave plate provided between the rod integrator and the first polarization separation prism;
Adjacent to the second side surface of the first polarization separation prism, the light having the second polarization direction reflected by the first polarization separation prism is incident and reflected in the third side surface direction, and the first polarization A second polarization separation prism having a second polarization separation surface that transmits light in a direction and emits the light from a fourth side surface that is provided alongside the first side surface;
A second quarter-wave plate adjacent to the third side;
A total reflection plate adjacent to a surface of the second quarter-wave plate opposite to a surface in contact with the second polarization separation prism;
A projection display apparatus comprising a dichroic mirror adjacent to the first side surface and the fourth side surface. The projection-type image display device according to claim 1, wherein the rod integrator has an incident end face area smaller than an exit end face area. The projection image display device according to claim 1, wherein the rod integrator has a reflection mirror on an inner peripheral surface. It said dichroic mirror includes a first dichroic mirror which transmits red light, a second dichroic mirror that transmits the blue light has a third dichroic mirror which transmits green light, according to claim 1 to 3 something Re or The projection type image display device according to 1. The projection type image display device according to claim 4, wherein the dichroic mirror further includes a fourth dichroic mirror that transmits white light. The projection type image display device according to claim 4, wherein at least one area of the first to third dichroic mirrors is different from other areas. The projection type image display device according to claim 1, wherein the dichroic mirror is configured to be detachable. The projection type image display apparatus according to any one of claims 4 to 6 , wherein the first and second polarization separation prisms and the first to third dichroic mirrors are spaced apart from each other.

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