JPH116989A - Irradiation device for liquid crystal projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make light linearly polarized light and to drastically improve polarization conversion efficiency by providing 1st and 2nd concave reflection mirrors, a white light source, a 1/4 wavelength plate disposed at the rear of the emitting aperture of the 2nd concave reflection mirror and a polarizing beam splitter disposed at the rear of the 1/4 wavelength plate. SOLUTION: A light beam emitted from the white light source 1 is partially reflected by a parabolic mirror 2 and converted into parallel beams. Then, it is partially reflected by an open spherical reflection mirror 3, and the reflected light beam passes through the focal position of the mirror 3, is reflected by the mirror 2 and converted into the parallel beams. The beams are made incident on the 1/4 wavelength plate 4 and made incident on a prism type beam splitter 5 after modulating the plane of polarization. A P polarized light component out of the light beam is transmitted through the beam splitter 5 and converted into the linearly polarized light, and an S polarized light component is reflected by reflection surfaces 6 and 7, passes through the plate 4 again and is converted into the circularly polarized light, which is partially reflected by the mirror 2 and converted into the P polarized light by the plate 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an irradiation device for a liquid crystal projector.

[0002]

2. Description of the Related Art In a conventional irradiation apparatus for a liquid crystal projector, the light collection efficiency and polarization efficiency are extremely poor, and the final light utilization efficiency is about 2%. The causes include insufficient light-collecting characteristics due to the size of the light source, and furthermore, since the liquid crystal light valve uses a polarizing plate and an analyzer, there are polarization conversion loss and absorption. In addition, the polarization characteristics may be insufficient due to the wavelength dependence of the optical element in the polarization conversion optical system.

[0003]

In the conventional irradiation apparatus for a liquid crystal projector, the efficiency of using light from a light source is as low as about 2%. The light source generally used is a metal halide lamp. However, since it is not a point light source, it is impossible to obtain perfect parallel light, but it is necessary to improve the light-collecting characteristics. Further, when irradiating the liquid crystal light valve, it is necessary that the light is linearly polarized light. However, since the light source is in a non-polarized state close to natural light, it must be efficiently converted to linearly polarized light.

[0004]

According to a first aspect of the present invention, there is provided a first concave reflector, a white light source disposed substantially at a focal point of the first concave reflector, and a focal point having a second focal point. A second concave reflecting mirror having an exit opening disposed so as to substantially coincide with the focal point of the first concave reflecting mirror, and a quarter disposed behind the exit opening of the second concave reflecting mirror; It is proposed to have a wave plate and a polarizing beam splitter arranged behind the quarter wave plate.

According to a second aspect of the present invention, a first concave reflecting mirror and a white light source disposed substantially at the focal position of the first concave reflecting mirror are opposed to each other so that the focal point substantially coincides with the focal point of the first concave reflecting mirror. It is proposed to have a collimator lens arranged in a predetermined manner, a quarter-wave plate arranged behind the collimator lens, and a polarizing beam splitter arranged behind the quarter-wave plate. . .

According to a third aspect of the present invention, there is provided an elliptical reflecting mirror having an opening, a white light source substantially disposed at a focal point on the opposite side to the opening side of the elliptical reflecting mirror, and a focal point having an opening on the elliptical reflecting mirror. Are provided with an aperture spherical reflecting mirror having an exit aperture disposed so as to substantially coincide with the focal point located on the opposite side, and disposed so that the focal point substantially coincides with the focal point located on the opening side of the elliptical reflecting mirror. It is proposed to have a collimator lens, a quarter-wave plate after the collimator lens, and a polarizing beam splitter after the quarter-wave plate.

According to a fourth aspect of the present invention, there is provided an elliptical reflecting mirror having an opening, a white light source substantially disposed at a focal point located on a side opposite to the opening of the elliptical reflecting mirror having an opening, A collimator lens disposed so as to substantially coincide with the focal point located on the aperture side, a quarter-wave plate disposed after the collimator lens, and a polarized beam disposed after the quarter-wave plate It is proposed to have a splitter.

According to a fifth aspect of the present invention, there is provided a condensing optical system including a white light source, a concave reflecting mirror for converting the light from the white light source into parallel rays, and converting the light from the condensing optical system into red light, green light, and blue light. First and second dichroic mirrors for separating light,
It has an optical element comprising a quarter-wave plate and a polarizing beam splitter for each of the separated red light, green light and blue light, and means for combining light beams from the respective optical elements through a dichroic mirror. Propose that.

[0009]

Embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an optical system showing an embodiment of the present invention. A part of the light emitted from the white light source 1 which is a metal halide lamp, a halogen lamp or a xenon lamp is reflected by the parabolic reflector 2. At this time, since the white light source 1 is disposed substantially at the focal position of the parabolic reflector 2, the reflected light beam is converted into substantially parallel light. Some light rays that are not directly reflected by the parabolic reflector 2 are reflected by an aperture spherical reflector 3 having a circular or rectangular aperture at the center. At this time, since the white light source 1 is disposed substantially at the focal position of the open spherical reflecting mirror 3, the reflected light passes through the focal position of the open spherical reflecting mirror 3, is reflected by the parabolic reflecting mirror 2, and It is converted to parallel light.

The light beam converted into parallel light as described above is a natural light and its polarization direction is random. The light beam converted into parallel light is incident on the quarter-wave plate 4, is subjected to polarization plane modulation, and is incident on the prism-type polarization beam splitter 5. here,
The P-polarized light component of the polarization-modulated light beam passes through the prism-type polarizing beam splitter 5, while the S-polarized light component is reflected by the reflection surfaces 6 and 7, and travels again toward the quarter-wave plate 4. The light is converted into circularly polarized light by passing through the quarter-wave plate 4. This is because the high-speed axis or the low-speed axis of the quarter-wave plate 4 is at an angle of 45 degrees with respect to the incident surface between the reflecting surfaces 6 and 7 of the prism-type polarizing beam splitter 5 and the incident light beam. The light beam converted into the circularly polarized light is reflected by the parabolic reflector 2 and passes through the white light source 1, and a part of the light is reflected again by the parabolic reflector 2 and converted into parallel light. The light is converted from circularly polarized light to P-polarized light by the plate 4 and passes through the prism-type polarizing beam splitter 5.

Among the light rays converted into circularly polarized light, there are light rays that are reflected by the parabolic reflecting mirror 2, pass through the white light source 1, and are reflected by the open spherical reflecting mirror 3. This light beam passes through the white light source 1 again, is further reflected by the parabolic reflector 2, and is converted into parallel light. The circularly-polarized light converted into parallel light is converted from circularly-polarized light into P-polarized light by a quarter-wave plate, and passes through the prism-type polarization beam splitter 5. The substantially parallel light beam converted into the linearly polarized light is guided to a conventionally well-known color separation optical system shown in FIG. With the optical system configured as described above, the light collection efficiency and the polarization conversion efficiency of the irradiation device for a liquid crystal projector are dramatically improved.

FIG. 2 is a schematic configuration diagram of an optical system showing an embodiment of the present invention. In FIG. 2, since the white light source 1, the parabolic reflector 2, and the aperture spherical reflector 3 are arranged at substantially the focal positions, the reflected light is transmitted through the aperture spherical reflector 3 and the quarter-wave plate 4. Is the same as the embodiment of FIG. In FIG. 2, the light beam incident on the quarter-wave plate 4 is subjected to polarization plane modulation, and is incident on a wire grid type polarization beam splitter 29. Here, among the light beams having been subjected to the polarization plane modulation, the S-polarized light component is transmitted through the wire grid type polarizing beam splitter 29, while the P-polarized light component is reflected and re-transmitted.
The light travels toward the quarter-wave plate 4 and passes through the quarter-wave plate 4 to be converted into circularly polarized light. Because 4
This is because the high-speed axis or the low-speed axis of the half-wave plate 4 is at an angle of 45 degrees with respect to the plane of incidence of the light beam incident on the wire grid type polarizing beam splitter 29. The light beam converted into the circularly polarized light is reflected by the parabolic reflector 2 and passes through the white light source 1, and a part of the light is reflected again by the parabolic reflector 2 and converted into parallel light. The light is converted from circularly polarized light into S-polarized light by the plate 4 and passes through the wire grid type polarizing beam splitter 29.

Among the light beams converted into circularly polarized light, there are light beams that are reflected by the parabolic reflector 2, pass through the white light source 1, and are reflected by the open spherical reflector 3. This light beam passes through the white light source 1 again, is further reflected by the parabolic reflector 2, and is converted into parallel light. The circularly polarized light converted into parallel light is converted from circularly polarized light into S-polarized light by a quarter-wave plate, and passes through a wire grid type polarizing beam splitter 29. The substantially parallel light beam converted into the linearly polarized light (S-polarized light) is guided to a conventionally well-known color separation optical system shown in FIG. With the optical system configured as described above,
The light collection efficiency and polarization conversion efficiency of the irradiation device for a liquid crystal projector are dramatically improved.

Next, a third embodiment will be described with reference to FIG. The difference from the embodiment of FIG. 1 is that the parabolic reflector 2 is a spherical reflector 8a, and the aperture spherical reflector 3 is a collimator lens 9. The white light source 1 is disposed substantially at the focal position of the spherical reflecting mirror 8a, and further disposed substantially at the focal position of the collimator lens 9. Therefore,
Most of the light emitted from the white light source 1 is a spherical reflecting mirror 8a.
The light is condensed by the collimator lens 9 and converted into parallel light. The light converted into parallel light is subjected to polarization plane modulation by the quarter-wave plate 4 and enters the prism-type polarization beam splitter 5, where the P-polarized light component is transmitted but the S-polarized light component is reflected by the reflection surfaces 6 and 7. You. The reflected S-polarized light component passes through the quarter-wave plate again and is converted into circularly polarized light.

Further, the light is condensed at the position of the white light source 1 by the collimator lens 9 and again becomes divergent light, reflected by the spherical reflecting mirror 8a, again condensed at the position of the white light source 1, and further becomes divergent light. The light is converted into parallel light by the lens 9. One-quarter of the circularly polarized light converted to parallel light
By transmitting the light through the wavelength plate 4, it is converted into P-polarized light, so that the light can be transmitted through the prism-type polarizing beam splitter 5. The substantially parallel light beam converted into the linearly polarized light is shown in FIG.
And a well-known color separation optical system shown in FIG.
As described above, by using the present invention, linearly polarized light can be efficiently obtained. Therefore, with this optical system, the light collection efficiency and the polarization conversion efficiency of the irradiation device for a liquid crystal projector are dramatically improved.

FIG. 4 illustrates a fourth embodiment. The difference from the embodiment shown in FIG. 3 is that the prism type polarizing beam splitter 5 is different from the wire grid type polarizing beam splitter 2 in FIG.
9 is being replaced. In FIG. 4, the light beam converted into parallel light by the collimator lens 9 is incident on the quarter-wave plate 4 and the wire grid type polarizing beam splitter 5, where the S-polarized light component is transmitted but the P-polarized light component is reflected. The reflected P-polarized component again passes through the quarter-wave plate and is converted into circularly polarized light.

Further, the light is condensed at the position of the white light source 1 by the collimator lens 9 and becomes divergent light again, is reflected by the spherical reflecting mirror 8a, is again condensed at the position of the white light source 1, and becomes divergent light again. The light is converted into parallel light by the lens 9. One-quarter of the circularly polarized light converted to parallel light
By transmitting the light through the wavelength plate 4, the light is converted into S-polarized light, and thus can be transmitted through the wire grid type polarizing beam splitter 5. The substantially parallel light beam converted into the linearly polarized light is guided to a conventionally well-known color separation optical system shown in FIG. As described above, by using the present invention, linearly polarized light can be efficiently obtained. Therefore, with this optical system, the light collection efficiency and the polarization conversion efficiency of the irradiation device for a liquid crystal projector are dramatically improved.

Next, a fifth embodiment will be described with reference to FIG. The difference from the embodiment of FIG. 3 is that the spherical reflecting mirror 8a is an ellipsoidal reflecting mirror 8b and an open spherical reflecting mirror is added, and the white light source 1 is located at a position almost coincident with the focal position on the side closer to the elliptical reflecting mirror 8b. And the collimator lens 9 is arranged such that its focal position substantially coincides with the other focal point of the elliptical reflecting mirror 8b. Therefore, most of the light emitted from the white light source 1 is condensed by the elliptical reflecting mirror 8b, the opening spherical reflecting mirror 3 and the collimator lens 9, and
It is converted to parallel light. The light beam converted into parallel light is subjected to polarization plane modulation by the quarter-wave plate 4 and is incident on the prism-type polarizing beam splitter 5, where the P-polarized light component is transmitted but the S-polarized light beam is transmitted.
The polarized light component is reflected by the reflecting surfaces 6 and 7. The reflected S-polarized light component passes through the quarter-wave plate again and is converted into circularly polarized light.

Further, the light is condensed by the collimator lens 9 at the focal point on the collimator lens 3 side of the elliptical reflecting mirror 8b, becomes divergent light again, and is reflected by the elliptical reflecting mirror 8b.
The light is condensed again at the position of the white light source 1, further diverges, converges at the focal position of the elliptical reflecting mirror 8b on the collimator lens 3 side, further diverges, and is converted into parallel light by the collimator lens 9. The circularly polarized light beam converted into parallel light is converted into P-polarized light by transmitting through the quarter-wave plate 4, and thus can be transmitted through the prism-type polarizing beam splitter 5. The substantially parallel light beam converted into the linearly polarized light is guided to a conventionally well-known color separation optical system shown in FIG. Therefore, the light collection efficiency and the polarization conversion efficiency of the irradiation device for a liquid crystal projector are significantly improved by the present optical system.

Next, a sixth embodiment will be described with reference to FIG. The difference from the embodiment of FIG. 5 is that the prism-type polarization beam splitter 5 in FIG. 5 is replaced with a wire grid type polarization beam splitter 29 in FIG. In FIG. 6, the light beam converted into parallel light by the collimator lens 9 is polarization-modulated by the quarter-wave plate 4, enters the wire grid type polarization beam splitter 29, and transmits S-polarized light components but P-polarized light. The components are reflected. The reflected P-polarized component again passes through the quarter-wave plate and is converted into circularly polarized light.

Further, the light is condensed by the collimator lens 9 at the focal position of the elliptical reflecting mirror 8b on the collimator lens 3 side, becomes divergent light again, and is reflected by the elliptical reflecting mirror 8b.
The light is condensed again at the position of the white light source 1, further diverges, converges at the focal position of the elliptical reflecting mirror 8b on the collimator lens 3 side, further diverges, and is converted into parallel light by the collimator lens 9. The circularly polarized light beam converted to parallel light is transmitted to the quarter-wave plate 4 to be converted to S-polarized light, so that it can pass through the wire grid type polarizing beam splitter 29. The substantially parallel light beam converted into the linearly polarized light (S-polarized light) is guided to a conventionally well-known color separation optical system shown in FIG. As described above, by using the present invention, the light-collecting efficiency and the polarization conversion efficiency of the irradiation device for a liquid crystal projector are dramatically improved.

FIG. 7 shows a well-known color separation optical system. The substantially parallel light rays converted to linearly polarized light are transmitted by the dichroic mirror 10 to red light, and the others are reflected. The reflected light is a dichroic mirror 11
Thereby, blue light is transmitted and green light is reflected. The transmitted blue light is reflected by the mirror 12 and is irradiated on the liquid crystal light valve 20 by the condenser lens 19. The blue light having the passed image information is a dichroic mirror 2
1 and is incident on the projection lens 22. The red light transmitted through the dichroic mirror 10 is reflected by the mirror 13 and is irradiated on the liquid crystal light valve 15 by the condenser lens 14. The transmitted red light passes through the dichroic mirror 16 and further passes through the dichroic mirror 2.
The light is reflected by 1 and enters the projection lens 22. The green light reflected by the dichroic mirror 11 is applied to the liquid crystal light valve 18 by the condenser lens 17. The transmitted green light is reflected by the dichroic mirror 16, further reflected by the dichroic mirror 21, and enters the projection lens 22.

Each pixel of the liquid crystal light valves 15, 18 and 20 is turned on and off according to image data, and the amount of transmitted light is controlled. The red light incident on the projection lens 22;
The blue and green image information is superimposed and projected on a screen as a final image. All the liquid crystal light valves used in the color separation optical system shown in FIG. 7 do not have a polarizing plate for polarization conversion on the light incident side, and the alignment direction of the liquid crystal and the polarization direction of the incident light coincide. Therefore, the projection efficiency can be improved.

Next, a seventh embodiment will be described.
FIG. 8 is a schematic configuration diagram of an optical system that separates a light beam condensed by a condensing optical system into red, blue, and green light and linearly polarizes it. The feature of the present invention is to use a combination of a quarter-wave plate and a prism-type polarizing beam splitter optimized for each central wavelength of red, blue and green, and have a linear polarization function independently for each color. It is configured as follows. That is, the quarter-wave plate 27 and the prism-type polarization beam splitter 28 are optimized for the center wavelength of red light, and the prism-type polarization beam splitter 28
The red light of the S-polarized light component reflected by the light returns to the condensing optical system except for the polarization conversion optical system described with reference to FIG. 1, FIG. 3 or FIG. 5, and is again subjected to the quarter-wave plate 27 and the prism type polarizing beam splitter. The red light enters the polarization conversion optical system consisting of 28 and is efficiently converted into P-polarized light. Similarly,
The quarter-wave plate 23 and the prism-type polarizing beam splitter 24 are optimized for the center wavelength of green, and the green light is efficiently converted to P-polarized light. Further, the quarter-wave plate 25 and the prism-type polarizing beam splitter 26 are optimized for the center wavelength of blue light, and the blue light is efficiently
Converted to polarized light.

As described above, since red, green and blue are independently subjected to P-polarization conversion, extremely high quality linearly polarized light can be obtained for each primary color. In this manner, the linearly polarized light beam enters the projection lens 22. Each pixel of the liquid crystal light valves 15, 18 and 20 is turned on and off according to image data, the amount of transmitted light is controlled, and red,
The blue and green image information is superimposed and projected on a screen as a final image. All the liquid crystal light valves used in the color separation optical system shown in FIG. 8 have no polarizing plate for polarization conversion on the light incident side, and the alignment direction of the liquid crystal and the polarization direction of the incident light are matched. , Can greatly improve the projection efficiency.

It is desirable that the reflectance and transmittance of the dichroic mirrors 10, 11, 16 and 21 and the mirrors 12 and 13 shown in the seventh embodiment of the present invention have small polarization dependence.

Next, an eighth embodiment shown in FIG. 9 will be described. 9, the difference from the embodiment of FIG. 8 is that the prism type polarization beam splitters 24, 2 in FIG.
6 and 28 are that the wire grid type polarizing beam splitter 29 is replaced in FIG. FIG. 9 is a schematic configuration diagram of an optical system that separates a light beam condensed by a condensing optical system into red, blue, and green light and linearly polarizes it. The feature of the present invention is to use the combination of the quarter-wave plate 4 and the wire grid type polarizing beam splitter 29 optimized for the respective center wavelengths of red, blue and green,
It is configured to have a linear polarization function independently for each color.

That is, the quarter-wave plate 4 and the wire grid type polarizing beam splitter 29 are optimized for the center wavelength of red, and the red light of the P-polarized component reflected by the wire grid type polarizing beam splitter 29 is Returning to the condenser optical system except for the polarization conversion optical system described in FIG. 2, FIG. 4 or FIG. 6, the light again enters the polarization conversion optical system including the quarter-wave plate 4 and the wire grid type polarization beam splitter 29. The red light is efficiently converted into S-polarized light. Similarly, the other quarter-wave plate 4 and the wire grid type polarizing beam splitter 29 are also optimized for green and blue center wavelengths, and efficiently convert green light into S-polarized light. As described above, since red, green, and blue are independently subjected to S-polarization conversion, extremely high-quality linearly polarized light can be obtained for each primary color. Therefore, with this optical system,
The light collection efficiency and polarization conversion efficiency of the irradiation device for a liquid crystal projector are dramatically improved.

FIG. 10 is a schematic structural view of an optical system showing an embodiment of the ninth invention. White light source 1 that is a metal halide lamp, halogen lamp or xenon lamp
Are reflected by the aperture ellipsoidal reflecting mirror 8c. At this time, the white light source 1 has an aperture elliptical reflecting mirror 8.
c is disposed substantially at the first focal position, and the reflected light beam is condensed substantially at the second focal position of the elliptical reflecting mirror 8c.
When the focal position of the collimator lens 9 is set substantially at the second focal position of the elliptical reflecting mirror 8c, the light beam condensed at the second focal position is converted by the collimator lens 9 into substantially parallel light. The behavior of the parallel light is the same as that described in the embodiment shown in FIGS. 1 and 3, and the substantially parallel light converted into the linearly polarized light is applied to a conventionally well-known color separation optical system shown in FIG. Be guided. Therefore, with this optical system, the light collection efficiency and the polarization conversion efficiency of the irradiation device for a liquid crystal projector are dramatically improved.

FIG. 11 is a schematic configuration diagram of an optical system showing an embodiment of the tenth invention. 11 differs from the embodiment of FIG. 10 in that the prism-type polarization beam splitter 5 in FIG. 10 is replaced with the wire-grid polarization beam splitter 29 in FIG. The luminous flux exiting is S
That is, it is polarized. The substantially parallel light beam converted into linearly polarized light composed of S-polarized light oscillating in a direction perpendicular to the wire grid is guided to a conventionally well-known color separation optical system shown in FIG. Therefore, with this optical system, the light collection efficiency and the polarization conversion efficiency of the irradiation device for a liquid crystal projector are dramatically improved.

Next, referring to FIGS. 12, 13, 14, 15, and 16, a wire grid type polarized light used in the illumination optical system of the embodiment of the present invention shown in FIGS. 2, 4, 6, 9, and 11 will be described. An example of a method for forming the beam splitter 29 will be described.

FIG. 12 shows a configuration principle diagram of a wire grid type polarizing beam splitter. The wire grid polarization splitter 37 is configured by arranging a number of parallel conductor lines 36, and the pitch (period) d of these parallel conductor lines 36 is larger than the wavelength of light incident on the wire grid polarization splitter 37. It has been made short. And
In this wire grid polarization splitter 37,
The P-polarized light whose polarization direction matches the direction of each parallel conductor line is reflected without passing through this wire grid polarization splitter 37. In the wire grid polarization splitter 37, S-polarized light whose polarization direction is perpendicular to the direction of each of the parallel conductor lines 36 is transmitted without being reflected by the wire grid polarization splitter 37. In this wire grid polarization splitter, when the width of each parallel conductor line 36 is a and the pitch (period) is d, it is preferable that (a / d) ≒ 0.6, and the wavelength of the light beam Is λ,
It is desirable that (λ / d) ≧ 5. Further, it is desirable that the refractive index of the transparent glass plate on which the wire grid is adhered is close to 1.

The wire grid polarization splitter 37
First, as shown in FIG. 13, a Ni—Cr (nickel chrome) layer 32 (having a thickness of 5 mm) is formed on one side of a glass substrate 34 on which antireflection films 33 and 35 are provided on both sides.
nm) and an Au (gold) layer 31 (thickness 100 nm) are formed by vacuum evaporation, and a photoresist layer 30 (thickness 300 nm) is further formed by spin coating. The Ni-Cr layer 32 is an undercoat for enhancing the adhesion between the antireflection film 33 and the Au layer 31.

Next, as shown in FIG. 14, holographic exposure is performed by two-beam interference of a He-Cd laser (emission wavelength: λ = 441.6 nm), and development is performed. In this state, the cross-sectional shape of the resist pattern becomes a half sinusoidal shape. Here, by controlling the exposure and development conditions,
A part of the Au layer 31 is exposed, and the above (a / d) approaches 0.6.

Then, as shown in FIG. 15, Ar (argon) ion beam etching is performed from the vertical direction. In this Ar ion beam etching, since the Au layer 31 is polished faster than the photoresist, only the exposed Au portion is removed including the Ni—Cr layer 32, and the photoresist portion remains. , A grid pattern is formed.

Next, as shown in FIG. 16, although not shown, the remaining photoresist is ashed and removed by plasma irradiation, thereby forming each of the parallel conductor lines (Au).
The wire grid polarization splitter 37 in which the lines 36 are arranged is created.

[0038]

By using the illuminating device for a liquid crystal projector of the present invention, the efficiency is extremely improved by combining a quarter-wave plate and a polarizing beam splitter instead of the polarizing plate used for linear polarization. Linear polarization can be achieved. Also, a synergistic effect of a condensing optical system using a combination of a parabolic reflecting mirror, an elliptical reflecting mirror, a spherical reflecting mirror, a collimator lens, and the like, and a polarization converting optical system using a combination of the above quarter-wave plate and a polarizing beam splitter. Is particularly large. Further, by independently providing the polarization conversion optical system for each of red, green and blue, the polarization conversion efficiency of the irradiation device for a liquid crystal projector can be remarkably improved.

[Brief description of the drawings]

FIG. 1 is a schematic optical system configuration diagram of an irradiation device for a liquid crystal projector of the present invention.

FIG. 2 is a schematic optical system configuration diagram of the irradiation device for a liquid crystal projector of the present invention.

FIG. 3 is a schematic optical system configuration diagram of an irradiation device for a liquid crystal projector of the present invention.

FIG. 4 is a schematic optical system configuration diagram of an irradiation device for a liquid crystal projector according to the present invention.

FIG. 5 is a schematic optical system configuration diagram of an irradiation device for a liquid crystal projector according to the present invention.

FIG. 6 is a schematic optical system configuration diagram of an irradiation device for a liquid crystal projector of the present invention.

FIG. 7 is a schematic configuration diagram of a conventional color separation optical system.

FIG. 8 is a schematic configuration diagram of a polarization conversion optical system and a color separation optical system of the present invention.

FIG. 9 is a schematic diagram of an optical system configuration of an irradiation device for a liquid crystal projector according to the present invention.

FIG. 10 is a schematic optical system configuration diagram of an irradiation device for a liquid crystal projector of the present invention.

FIG. 11 is a schematic optical system configuration diagram of an irradiation device for a liquid crystal projector of the present invention.

FIG. 12 is a configuration principle diagram of a wire grid type polarization beam splitter used in the present invention.

FIG. 13 is a diagram of a wire grid type polarizing beam splitter forming step used in the present invention.

FIG. 14 is a diagram of a wire grid type polarizing beam splitter forming process used in the present invention.

FIG. 15 is a diagram of a wire grid type polarizing beam splitter forming process used in the present invention.

FIG. 16 is a diagram of a wire grid type polarizing beam splitter forming process used in the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 white light source 2 parabolic reflector 3 open spherical reflector 4 quarter-wave plate 5 prism-type polarizing beam splitter 6 reflective surface 7 reflective surface 8 a spherical reflector 8 b elliptical reflector 9 collimator lens 10 dichroic mirror 11 Dichroic mirror 12 Mirror 13 Mirror 14 Condenser lens 15 Liquid crystal light valve 16 Dichroic mirror 17 Condenser lens 18 Liquid crystal light valve 19 Condenser lens 20 Liquid crystal light valve 21 Dichroic mirror 22 Projection lens 23 Quarter wave plate 24 Prism type polarizing beam splitter 25 Quarter-wave plate 26 Prism-type polarizing beam splitter 27 Quarter-wave plate 28 Prism-type polarizing beam splitter 29 Wire grid-type polarizing beam splitter 30 Regis G 31 Au film 32 Ni-Cr film 33 Anti-reflection film 34 Base 35 Anti-reflection film 36 Conductor line 37 Wire grid polarization splitter

Claims (8)

[Claims] A first concave reflecting mirror, a white light source disposed substantially at a focal point of the first concave reflecting mirror, and a white light source facing the first concave reflecting mirror such that the focal point substantially coincides with the focal point of the first concave reflecting mirror; A second concave reflector having an exit aperture disposed therein, and a quarter disposed behind the exit aperture of the second concave reflector.
An irradiation device for a liquid crystal projector, comprising: a wave plate; and a polarizing beam splitter disposed behind the quarter wave plate. 2. The illuminating device for a liquid crystal projector according to claim 1, wherein said first concave reflecting mirror is a parabolic reflecting mirror, and said second concave reflecting mirror is a spherical reflecting mirror. 3. A first concave reflecting mirror, a white light source disposed substantially at a focal position of the first concave reflecting mirror, and a white light source facing the first concave reflecting mirror such that the focal point substantially coincides with the focal point of the first concave reflecting mirror. A collimator lens disposed, a quarter-wave plate disposed behind the collimator lens, and a polarizing beam splitter disposed behind the quarter-wave plate. Irradiation equipment for liquid crystal projectors. 4. An ellipsoidal reflecting mirror having an opening, a white light source substantially disposed at a focal point opposite to the opening side of the elliptical reflecting mirror, and a focal point at an opening side of the elliptical reflecting mirror. An open spherical reflecting mirror having an exit aperture disposed so as to substantially coincide with a focal point located on the opposite side, and disposed so that the focal point substantially coincides with a focal point located on the opening side of the elliptical reflecting mirror. A collimator lens, a quarter-wave plate subsequent to the collimator lens, and 4
An irradiation device for a liquid crystal projector, comprising: a polarizing beam splitter provided after a half-wave plate. 5. An elliptical reflecting mirror having an opening, a white light source substantially disposed at a focal point located on the opposite side of the opening of the elliptical reflecting mirror having the opening, and a focal point having an opening of the elliptical reflecting mirror. A collimator lens disposed so as to substantially coincide with a focal point located on the side, a quarter-wave plate provided behind the collimator lens, and a polarized light provided behind the quarter-wave plate An irradiation device for a liquid crystal projector, comprising: a beam splitter. 6. A condensing optical system including a white light source, a concave reflecting mirror that converts light from the white light source into parallel light, and converting the light from the condensing optical system into red light, green light, and blue light. First and second dichroic mirrors, an optical element comprising a quarter-wave plate and a polarizing beam splitter for each of the separated red light, green light, and blue light; and the respective optical elements Means for synthesizing the light beams via a dichroic mirror. 7. The polarizing beam splitter according to claim 1, wherein the polarizing beam splitter is a prism type polarizing beam splitter.
7. The irradiation device for a liquid crystal projector according to any one of items 1 to 6. 8. The irradiation device for a liquid crystal projector according to claim 1, wherein the polarization beam splitter is a wire grid type polarization beam splitter.