JPH09297352A - Projection display device - Google Patents

Abstract

(57) Abstract: A polarized light component absorbed by a transmissive liquid crystal light valve is reduced to reduce heat generation. A light beam from a light source is polarized and split by a polarization beam splitter into P-polarized light and S-polarized light. The dichroic mirror 23 reflects only B light of P polarized light, and this B light is converted into S polarized light by the ½ wavelength plate 27 and transmitted through the light valve 28 to be modulated. The dichroic mirror 24 reflects only the G light of the S polarized light, and this G light is transmitted through the light valve 29 and modulated. The dichroic mirror 25 reflects only R light of S polarized light,
This R light passes through the light valve 30 and is modulated. The modulated lights of the respective colors are combined by the dichroic prism 31 and projected by the projection lens 34.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a transmissive liquid crystal light valve, irradiates the transmissive liquid crystal light valve with irradiation light, and transmits modulated signal projection light through the transmissive liquid crystal light valve. The present invention relates to a device for projecting with a projection lens, particularly to a full-color projection display device.

[0002]

2. Description of the Related Art Conventionally, color lights of three primary colors (red light (R
Light), green light (G light), and blue light (B light)) are provided for the respective three types of transmissive liquid crystal light valves, and an image signal for each color is applied to each transmissive liquid crystal light valve. , A full-color projection display device in which light that is incident on a transmissive liquid crystal light valve for each color light and is modulated by the image signal and transmitted is subjected to color synthesis by a color synthesis optical system and projected onto a screen by a projection lens. Are known.

A conventional example of such a projection type display device will be described with reference to FIG. FIG. 4 is a schematic configuration diagram of a conventional projection type display device.

In this conventional projection type display device, the light source 1
Is composed of a lamp 1a, a concave mirror 1b arranged at the back of the lamp 1a, and a condenser lens (not shown) arranged at the front of the lamp 1a, and contains R, G, and B light components. It emits white substantially parallel light. White light emitted from the light source 1 passes through an infrared cut filter and an ultraviolet cut filter (not shown), and is passed through an R, G, B color separation optical system including a B light reflection dichroic mirror 2 and a G light reflection dichroic mirror 3. Color is separated into light. That is, the substantially parallel white light first enters the B-light reflecting dichroic mirror 2 arranged so as to be incident at about 45 degrees with respect to the optical axis, and only the B-light is reflected by the dichroic mirror 2. The R, G lights pass through the dichroic mirror 2. G transmitted through the dichroic mirror 2,
The R light is G which is arranged substantially parallel to the dichroic mirror 2.
The light is incident on the light reflection dichroic mirror 3, only the G light is reflected by the dichroic mirror 3, and the R light is transmitted through the dichroic mirror 3. The R light transmitted through the dichroic mirror 3 is reflected by the reflection mirror 4 which is arranged substantially parallel to the dichroic mirrors 2 and 3. The color-separated B, G, and R lights travel in parallel with each other, and
The light and the R light are reflected by the reflection mirrors 5 and 13, respectively, and are transmitted to the transmissive liquid crystal light valves 6, 7 and 8 which are arranged close to the three side surfaces of the cross dichroic prism 9 as a color synthesizing optical system. The light beams are made incident substantially vertically.

The transmissive liquid crystal light valves 6, 7 and 8 are
The incident light is modulated by the image signal for each color and transmitted,
An optical image is formed and transmitted as a change in transmittance. A transmissive liquid crystal light valve typically has a structure in which both surfaces of a liquid crystal panel are sandwiched by two polarizing plates. The G light modulated by the liquid crystal light valve 7 for G light and transmitted therethrough enters the cross dichroic prism 9, and the R light arranged inside the cross dichroic prism 9 in an X shape.
The light is transmitted through the light reflection dichroic film 11 and the B light reflection dichroic film 10. The R light modulated by the R light liquid crystal light valve 8 and transmitted therethrough enters the cross dichroic prism 9 and is reflected by the R light reflecting dichroic film 11. Further, the B light that has been modulated by the B light liquid crystal light valve 6 and transmitted therethrough enters the cross dichroic prism 9 and is reflected by the B light reflecting dichroic film 10. As described above, the color-modulated lights are combined by the cross dichroic prism 9 and emitted from the cross dichroic prism 9. The light that has been color-synthesized and emitted from the cross dichroic prism 9 is projected as a full-color projection image on a screen (not shown) by the projection lens 12. The projection lens 12 has an aperture stop 12a.

[0006]

However, the above-mentioned conventional projection type display device shown in FIG. 4 has the following two drawbacks.

That is, the liquid crystal light valves 6, 7, 8
As described above, the liquid crystal panel has a structure in which both sides of the liquid crystal panel are sandwiched by polarizing plates, and functions as a transmissive liquid crystal light valve. Light of each color obtained by color-separating the light from the light source enters the polarizing plate of the liquid crystal light valve, transmits a predetermined polarized component of the light, and the remaining polarized component is absorbed by the polarizing plate and converted into heat. To be done. In order to project a bright image, the power of the light source must be increased, and the amount of heat absorbed by the polarizing plate inevitably increases, which causes the polarizing plate to lose its function.

Further, the light source 1 emits white light by converting it into substantially parallel light, but since it has a property that the light spreads as the distance advances, especially for R light, other B, Since the optical path length to the transmissive liquid crystal light valve is longer than that of the G light, the light utilization efficiency is deteriorated.

The present invention has been made in order to eliminate the drawbacks of the conventional projection type display device, and it is possible to reduce the polarized component absorbed by the transmissive liquid crystal light valve to reduce heat generation. An object is to provide a mold display device.

It is another object of the present invention to provide a projection type display device capable of improving the light utilization efficiency of the light source light.

[0011]

In order to solve the above-mentioned problems, a projection type display apparatus according to the first aspect of the present invention includes a light source for emitting light having color light components of three primary colors, and a light emitted from the light source. A polarized beam splitter that polarizes and separates the polarized light into two polarized lights having different polarization states, and one of the three primary color lights by color-separating one of the two polarized lights that are polarized and separated by the polarized beam splitter. A first color separation optical system for obtaining color light, and a second color separation for color separation of the other of the two polarization-split polarized lights to obtain the remaining two color lights of the three primary color lights. An optical system and three transmissive liquid crystal light valves provided corresponding to respective colors, wherein the one color light obtained from the first color separation optical system and the three color separation optical systems obtained from the second color separation optical system are provided. Said 2
Three transmissive liquid crystal light valves into which the three color lights are respectively incident, a color synthesizing optical system that color-synthesizes the transmitted lights of the respective colors that have been modulated by transmitting through the three transmissive liquid crystal light valves, and the color synthesizing optics. And a projection optical system that projects the transmitted light of each color that is color-synthesized by the system.

According to the first aspect, the light emitted from the light source is polarized and separated into two polarized lights, and only one of the lights is incident on each transmissive liquid crystal light valve. Compared to the case where the light source light is not polarized and separated and is incident on each transmissive liquid crystal light valve as it is as in the projection display device, the light is absorbed by the incident side polarization plate of the transmissive liquid crystal light valve. The polarized light component is significantly reduced, and heat generation is significantly reduced. Therefore, even if the light source has a high output, the polarizing plate of the transmissive liquid crystal light valve will not lose its function due to heat.

In the first aspect, the polarization direction of the polarized light incident on the transmissive liquid crystal light valve is the same in order not to reduce the amount of light transmitted through the transmissive liquid crystal light valve and to reduce heat generation. Polarization components that are not absorbed by the incident side polarization plate of the transmissive liquid crystal light valve (that is,
It is preferable that the polarization direction of the polarization component that passes through the incident side polarization plate and the like is the same. For this purpose, for example, the arrangement or configuration of each transmissive liquid crystal light valve itself may be set according to the polarized light of the polarized light incident on the transmissive liquid crystal light valve, or conversely, the present invention described later As in the second aspect, a polarization component that transmits the polarization direction of the polarized light incident on the transmissive liquid crystal light valve through the incident side polarization plate of the transmissive liquid crystal light valve by using a half-wave plate or the like. It may be set according to the polarization direction of.

A projection type display device according to a second aspect of the present invention is the projection type display device according to the first aspect, wherein at least one of the three transmission type liquid crystal light valves is used.
A half-wave plate is arranged between two transmissive liquid crystal light valves and the polarization beam splitter. According to the second aspect, as described above, by using the half-wave plate, the polarization direction of the polarized light incident on the transmissive liquid crystal light valve is changed to the incident side polarization plate of the transmissive liquid crystal light valve. Can be set according to the polarization direction of the polarization component that transmits the light.

A projection type display apparatus according to a third aspect of the present invention is arranged at an elliptical mirror and a position of a first focal point of the elliptic mirror.
A light source having a lamp that emits light having a color light component of a primary color and a rod integrator whose end portion is arranged at the position of the second focal point of the elliptic mirror, and light emitted from the light source having different polarization states from each other. A polarized beam splitter that splits the polarized light into two polarized lights; and a first color that separates one of the two polarized lights split by the polarized beam splitter to obtain one colored light of the three primary colors. Decomposition optical system, a second color separation optical system for color-separating the other of the two polarized light beams that have been polarized and separated to obtain the remaining two color light beams of the three primary color lights, and corresponding to each color And the two color lights obtained from the second color separation optical system and the one color light obtained from the first color separation optical system. Each is incident One transmissive liquid crystal light valve, a color synthesizing optical system for synthesizing the transmitted light of the respective colors transmitted through the three transmissive liquid crystal light valves, and a color synthesizing optical system for synthesizing the colors. And a projection optical system for projecting transmitted light.

Also in the third mode, the light emitted from the light source is polarized and separated into two polarized lights, and only one of the lights is incident on the transmissive liquid crystal light valve.
Similar to the first aspect, the polarization component absorbed by the incident side polarization plate of the transmissive liquid crystal light valve is greatly reduced, and heat generation is significantly reduced. In the third aspect, the light source is arranged at the position of the elliptic mirror and the first focal point of the elliptic mirror.
Since the lamp that emits light having the color light components of the primary colors and the rod integrator whose end portion is arranged at the position of the second focal point of the elliptic mirror, the emitting end surface of the rod integrator has a uniform brightness. It is substantially equivalent to the light source.
Therefore, by forming an image of the exit end face of the rod integrator on the transmissive liquid crystal light valve, the light that enters the transmissive liquid crystal light valve can be illuminated by the so-called critical illumination method, and the light from the light source is used. The efficiency can be improved.

A projection type display device according to a fourth aspect of the present invention is the projection type display device according to the third aspect, wherein
A half-wave plate is disposed between at least one of the transmission type liquid crystal light valves and the polarization beam splitter. This fourth
According to this aspect, similarly to the second aspect, by using the half-wave plate, the polarization direction of the polarized light incident on the transmissive liquid crystal light valve is changed to the incident side polarization plate of the transmissive liquid crystal light valve. It can be set according to the polarization direction of the polarization component that transmits the light.

A projection type display device according to a fifth aspect of the present invention is the projection type display device according to the third or fourth aspect, wherein the projection optical system has an aperture stop and the three transmission type liquid crystal lights. The valve and the color combining optical system are arranged at a position where the chief ray determined by the aperture stop has telecentricity.

According to the fifth aspect, since the transmissive liquid crystal light valve and the color synthesizing optical system are arranged at the position where the chief ray has telecentricity, the incident light to the transmissive liquid crystal light valve is concerned. The light will enter the transmissive liquid crystal light valve substantially vertically. Therefore, the performance of the liquid crystal panel or the like that constitutes the transmissive liquid crystal light valve is the best when the incident direction is substantially vertical depending on the incident angle of the incident light to the transmissive liquid crystal light valve,
Image quality can be improved.

The projection type display apparatus according to a sixth aspect of the present invention is the projection type display apparatus according to any one of the third to fifth aspects, wherein the projection type display apparatus is provided between the emitting end of the rod integrator and the polarization beam splitter. , A first field lens and a first relay lens are arranged in this order from the emission end side of the rod integrator, and the one color light obtained by the first color separation optical system is incident on the transmission type liquid crystal light valve. A second field lens is disposed between the polarization beam splitter and the polarization beam splitter, and one of the two color lights obtained by the second color separation optical system is incident on the transmissive liquid crystal light valve. Between the polarization beam splitter and a position where the other color light of the two color lights obtained by the second color separation optical system is not involved. A third field lens is arranged, and between the transmission type liquid crystal light valve on which the other color light of the two color lights obtained by the second color separation optical system is incident and the polarization beam splitter, A fourth field lens, a fifth field lens, a second relay lens and a sixth field lens are provided at a position where one of the two color lights obtained by the second color separation optical system is not involved. Arranged in this order from the polarization beam splitter side, a real image of the exit end face of the rod integrator is formed between the fourth field lens and the fifth field lens.

The sixth aspect is a specific example of the third to fifth aspects, and is an example in which a relay field lens system is adopted. By adopting such a relay / field lens system, it is possible to eliminate waste of use of light from the light source due to a difference in optical path length from the light source to the liquid crystal light valve for each color.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a projection type display device according to the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic configuration diagram showing a projection type display device according to a first embodiment of the present invention. In the projection display apparatus according to the present embodiment, the light source 21 includes a lamp 21a, a concave mirror arranged at the back of the lamp 21a, and a shaping optical system such as a condenser lens (not shown) arranged at the front of the lamp 21a. And have R, G, B
It emits white substantially parallel light including a light component. The white light emitted from the light source 21 passes through an infrared cut filter and an ultraviolet cut filter (not shown), enters the polarization beam splitter 22, and is transmitted through the polarization splitting unit P.
The polarized light and the S-polarized light reflected by the polarized light separating portion are polarized and separated. The P-polarized light including the R, G, and B light components transmitted through the polarization beam splitter 22 is incident on the B-light reflection dichroic mirror 23 at an incident angle of about 45 degrees, and the P-polarized light is reflected by the B-light reflection dichroic mirror 23. Of the P-polarized light, only the B light is reflected and the optical axis is changed to a right angle, and the other color lights (G, R lights) of the P-polarized light are transmitted through the dichroic mirror 23 and discarded. In the present embodiment, the B-light reflection dichroic mirror 23 color-separates the P-polarized light polarized and separated by the polarization beam splitter 22 to obtain one of the three primary color lights. Are configured. The P-polarized B light reflected by the dichroic mirror 23 is transmitted through the B-light transmissive liquid crystal light valve 28.
The light passes through the half-wave plate 27 that is arranged immediately before the incident light, is converted into S-polarized light, and is incident on the liquid crystal light valve 28 substantially vertically. On the other hand, the S-polarized light including the R, G, B lights reflected by the polarization beam splitter 22 is a G-light reflection dichroic mirror 2 arranged at about 45 degrees with respect to the optical axis.
4, the G light reflection dichroic mirror 24 reflects only the G light of the S polarized light to change the optical axis to a right angle, and the other colored light (R, B light) of the S polarized light. Passes through the dichroic mirror 23. The S-polarized G light reflected by the G light reflection dichroic mirror 24 enters the transmissive liquid crystal light valve 29 for G light substantially vertically.
The S-polarized R and B lights that have passed through the dichroic mirror 23 enter the R-light reflection dichroic mirror 25 that is arranged at approximately 45 degrees with respect to the optical axis, and the R-light reflection dichroic mirror 25 only S-polarized R light Is reflected to change the optical axis to a right angle, and the B light of the S-polarized light is transmitted through the R light reflecting dichroic mirror 25 and is discarded. The R light of the S-polarized light reflected by the R light reflection dichroic mirror 25 is further reflected by the reflection mirror 26 arranged at 45 degrees with respect to the optical axis, and is substantially perpendicular to the transmissive liquid crystal light valve 30 for the R light. Is incident on. In this embodiment, the dichroic mirrors 24 and 25 are the second color separation optics for color-separating the S-polarized light polarized and separated by the polarization beam splitter 22 to obtain the remaining two color lights of the three primary color lights. It constitutes the system.

Transmissive liquid crystal light valves 28, 29, 30
Modulates incident light with an image signal for each color and transmits the modulated light, and forms and transmits an optical image as a change in transmittance.
The transmissive liquid crystal light valves 28, 29, 30 are, for example,
The liquid crystal panel has a structure in which both surfaces are sandwiched by two polarizing plates, and the polarization direction of the polarizing plate on the incident side is set to transmit the S polarized light when the S polarized light is incident. . Although not shown in the drawing, a TFT (thin film transistor), which is a switching element for each pixel, is formed on the incident light side glass substrate in the liquid crystal panel,
The structure is such that a voltage is applied between the liquid crystals for each pixel by switching of the TFT according to an image signal. Between the glass substrate on the emission side and the glass substrate on the incidence side, TN
The liquid crystal is oriented so that the liquid crystal molecules have a twist of 90 degrees when no voltage is applied, and the incident S-polarized light is rotated by the arrangement of the molecules and changes in the polarization direction of 90 degrees. The received light is transmitted as P-polarized light and transmitted through the liquid crystal panel, and further transmitted through a polarizing plate on the emission side arranged in a direction in which only P-polarized light is transmitted. When the TFT is driven and a voltage is applied, the incident S-polarized light is transmitted through the liquid crystal panel as it is as S-polarized light, and is not transmitted through the polarization panel on the emission side and is absorbed. As can be seen from the above description, the light transmitted through each transmissive liquid crystal light valve 28, 29, 30 is modulated by the image signal for each color.

Each transmissive liquid crystal light valve 28,
The respective color lights that have been transmitted through the light beams 29 and 30 and have been modulated are arranged substantially parallel to each other by the transmissive liquid crystal light valves 28, 29, and 30 being close to the side faces of the dichroic prism 31 as the color combining optical system. , Dichroic prism 31
Will be incident. Dichroic prism 31
Has an R-light reflection dichroic film 32 and a B-light reflection dichroic film 33 arranged in an X shape inside,
The incident color-modulated lights are color-synthesized. That is, the incident modulated light of B light is reflected by the B light reflecting dichroic film 33, the incident modulated light of R light is reflected by the R light reflecting dichroic film 32, and the incident modulated light of G light is dichroic film. After passing through 32 and 33, they are color-combined and emitted from the cross dichroic prism 31. Then, the color-synthesized cross dichroic prism 31
The light emitted from the projection lens 34 serves as a projection optical system.
Is projected as a full-color projection image on a screen (not shown). The projection lens 34 is used as the aperture stop 3
4a.

According to the present embodiment, the light emitted from the light source 21 is polarized and separated into the two polarized lights of P-polarized light and S-polarized light, and each of the transmissive liquid crystal light valves 28, 29, 30 has either of them. Since only one of the light beams is incident, compared with the case where the light source light is not polarized and separated as in the conventional projection type display device described above and is incident on each transmissive liquid crystal light valve as random polarized light, it is transmitted. Type liquid crystal light valve 2
The polarized components absorbed by the incident side polarization plates of 8, 29, 30 and the like are greatly reduced, and heat generation is greatly reduced. Therefore, even if the light source 21 has a high output, the transmissive liquid crystal light valve 2
The polarizing plates of 8, 29, 30 and the like will not lose their functions due to heat.

In this embodiment, as described above, any of the transmissive liquid crystal light valves 28, 29, 30 is used.
Also, since the polarization direction of the polarizing plate on the incident side is set to the direction in which the S-polarized light is transmitted when the S-polarized light is incident, the amount of transmitted light of the transmissive liquid crystal light valve is not reduced and heat is generated. In order to reduce the light, not only the light incident on the transmissive liquid crystal light valves 29 and 30 but also the light incident on the transmissive liquid crystal light valve 28 is converted into S-polarized light. The half-wave plate 27 is disposed only between the light valve 28 and the light valve 28.

However, in order not to reduce the amount of transmitted light of the transmissive liquid crystal light valve and to reduce the generation of heat, the polarization direction of the polarized light incident on the transmissive liquid crystal light valves 28, 29, and 30 and the transmissive type. Liquid crystal light valve 2
It suffices that the polarization directions of the polarization components that are transmitted through the incident side polarization plates of 8, 29 and 30 are the same. So, for example,
In the present embodiment, the transmissive liquid crystal light valve 28
Is configured so that the polarization direction of the incident-side polarization plate transmits P-polarized light (of course, in accordance with this, the polarization direction of the emission-side polarization plate of the transmission type liquid crystal light valve 28 and the alignment treatment of the liquid crystal panel). The direction can be set.), And the half-wave plate 27 can be removed. Similarly, if the transmissive liquid crystal light valves 28, 29, 30 are configured in accordance with the polarization direction of the incident polarized light, the half-wave plate 27 is removed and the transmissive liquid crystal light valves 29, 30 are provided in front. 1 each
It is possible to dispose a 1/2 wavelength plate or to dispose the 1/2 wavelength plate in front of each of the transmissive liquid crystal light valves 29 and 30 without removing the 1/2 wavelength plate 27.

In this embodiment, as the transmissive liquid crystal light valves 28, 29 and 30, the polarizing plates are respectively arranged on the incident side, but when the polarization separation characteristic of the polarization beam splitter 22 is good. In addition, since the linearly polarized light is directly incident on the liquid crystal panel in a predetermined direction, the incident side polarization plate may be omitted.

In this embodiment, the polarization beam splitter 22 has a structure in which two triangular prisms sandwich a polarization separation film. The polarization beam splitter having such a structure is preferable because it has superior polarization separation characteristics to the plate-shaped polarization beam splitter.
However, in the present invention, the type of the polarization beam splitter 22 used is not limited.

(Second Embodiment) FIG. 2 is a schematic structural view showing a projection type display device according to a second embodiment of the present invention. In the projection display device according to the present embodiment, the light source 41 includes an elliptic mirror 43, a lamp 42 arranged at the position of the first focal point of the elliptic mirror 43, and emitting a light having R, G, B light components. And a rod integrator 44 made of a transparent glass rod having a rectangular parallelepiped shape. The end of the rod integrator 44 on the lamp 42 side is arranged at the position of the second focal point of the elliptical mirror 43. In the present embodiment, an ultraviolet cut filter and an infrared cut filter are arranged between the lamp 42 and the rod integrator 44, but they are omitted in FIG. In this light source 41, it can be considered that there is a surface light source having a uniform brightness in its shape at the other end (emission end, left end in FIG. 2) of the rod integrator 44.

The projection type display device according to the present embodiment includes a polarization beam splitter 22 shown in FIG. 1, a dichroic mirror 23 as a first color separation means, and dichroic mirrors 24, 25 as a second color separation optical system. The half-wave plate 27, the transmissive liquid crystal light valves 28, 29, 30 correspond to the dichroic prism 31 as a color combining optical system and the projection lens 34 as a projection optical system, respectively.
Polarization beam splitter 48, dichroic mirror 49 as first color separation means, dichroic mirrors 52 and 55 as second color separation means, 1/2 wavelength plate 51,
It has transmissive liquid crystal light valves 60, 61, 62, a dichroic prism 63 as a color combining optical system, and a projection lens 66 as a projection optical system. In the present embodiment, the transmissive liquid crystal light valves 60, 61, 62 are used.
Is the transmissive liquid crystal light valve 28, 29, 30 described above.
It has the same structure as.

In this embodiment, the transmissive liquid crystal light valves 60, 61, 62 and the dichroic prism 63 are arranged at positions where the principal ray determined by the aperture stop 66a of the projection lens 66 has telecentricity. There is. Specifically, in the present embodiment, the emission end of the rod integrator 44 and the polarization beam splitter 48.
And the first field lens 45 and the first relay lens 47 are arranged in this order from the emission end side of the rod integrator 44. A second field lens 50 is arranged between the transmission type liquid crystal light valve 60 and the polarization beam splitter 48 on which the B light obtained by the B light reflection dichroic mirror 49 is incident. Two-color light (G) obtained by the dichroic mirrors 52 and 55
Between the transmission type liquid crystal light valve 61 and the polarization beam splitter 48 on which G light of the light (R light) is incident,
The third field lens 59 is arranged at a position where the R light of the two color lights obtained by the dichroic mirrors 52 and 55 is not involved (that is, a position where the R light is not affected). Between the transmissive liquid crystal light valve 62 on which the R light of the two color lights obtained by the dichroic mirrors 52 and 55 is incident and the polarization beam splitter 48, of the two color lights obtained by the dichroic mirrors 52 and 55. Positions where G light is not involved (ie
The fourth field lens 53, the fifth field lens 54, the second relay lens 56, and the sixth field lens 58 are arranged in this order from the polarization beam splitter 48 side at a position (that does not affect the G light). There is. A real image of the exit end face of the rod integrator 44 is formed between the fourth field lens 53 and the fifth field lens 54.

Field lens 45, relay lens 47
The field lens 50 forms an illumination optical system for the transmissive liquid crystal light valve 60 for B light. The field lens 45, the relay lens 47, and the field lens 59 form an illumination optical system for the transmissive liquid crystal light valve 61 for G light. The field lens 45, relay lens 47, field lens 53, field lens 54, relay lens 56 and field lens 58 are
An illumination optical system for the transmissive liquid crystal light valve 62 for R light is formed.

Next, the operation of the projection type display device according to the present embodiment will be described with reference to FIGS. FIG. 3 is a principal ray diagram schematically showing a state of a principal ray determined by the aperture stop 66a of the projection lens 66 of the projection type display device according to the present embodiment, and FIG. The state of the chief ray regarding the G light is shown, and FIG. 3B shows the state of the chief ray regarding the R light. Note that, in FIG. 3, in order to facilitate understanding, it is assumed that each light is not reflected and the optical axis is in a straight line, and the polarized beam 48, the dichroic mirrors 49, 52, 55, the half-wave plate 51, the reflection The mirrors 55 and 57 and the dichroic prism 63 are omitted.

The light source light containing the R, G, and B light components is emitted from the end of the rod integrator 44, passes through the field lens 45, changes the optical axis at a right angle by the reflection mirror 46, and the relay lens 47 passes through. After passing through the polarized beam splitter 48, the polarized beam splitter 48 splits the polarized light into P-polarized light that passes through the polarized beam splitter and S-polarized light that is reflected by the polarized beam splitter. The P-polarized light including the R, G, B light components transmitted through the polarization beam splitter 48 is
Only the B light of the P-polarized light is reflected by the B-light reflection dichroic mirror 49 arranged at an angle of about 45 degrees with respect to the optical axis, and the optical axis is changed to a right angle. The G and R lights pass through the dichroic mirror 49 and are discarded.

The P-polarized B light reflected by the dichroic mirror 49 passes through the field lens 50 and the half-wave plate 51 arranged immediately before the incidence of the B-light transmissive liquid crystal light valve 60. After passing through, the light is converted into S-polarized light and enters the transmissive liquid crystal light valve 60 to illuminate it. As shown in FIG. 3A, the relay lens 47 is a rod integrator 44 so as to realize the critical illumination method.
It has a function of forming an image on the emission end face of the image on the transmissive liquid crystal light valve 60. And the transmissive liquid crystal light valve 6
Since the liquid crystal panel of 0 depends on the performance depending on the incident angle,
The field lens 45 and the field lens 50 are used in order to make the liquid crystal light valve 60 enter substantially vertically. That is, as shown in FIG. 3A, the telecentricity is ensured.

On the other hand, the S-polarized light including the R, G, B lights reflected by the polarization beam splitter 48 is approximately 4 with respect to the optical axis.
It is incident on the G light reflection dichroic mirror 52 arranged at 5 degrees, and the S light is reflected by the G light reflection dichroic mirror 52.
Only G light of the polarized light is reflected to change the optical axis to a right angle, and the other color lights (R and B lights) of the S polarized light are transmitted through the dichroic mirror 52. The G light of the S-polarized light reflected by the G light reflection dichroic mirror 52 enters the liquid crystal light valve 61 for G light via the field lens 59 and illuminates it. As shown in FIG. 3A, the relay lens 47 has a function of forming an image of the emission end face of the rod integrator 44 on the transmissive liquid crystal light valve 61 so as to realize the critical illumination method. And
Since the performance of the liquid crystal panel of the transmissive liquid crystal light valve 61 depends on the incident angle, the field lens 45 and the field lens 59 are used to make the liquid crystal light valve 61 enter substantially perpendicularly. That is, as shown in FIG. 3A, the telecentricity is ensured. On the other hand, R of S-polarized light transmitted through the dichroic mirror 52,
The B light enters the R light reflection dichroic mirror 55 arranged at 45 degrees with respect to the optical axis via the field lenses 53 and 54, and only the R light of the S polarized light is reflected by the R light reflection dichroic mirror 55. Then, the optical axis is changed to a right angle, and the B light of the S-polarized light is reflected by the R light reflecting dichroic mirror 55.
And is discarded. The R light reflected by the R light reflection dichroic mirror 55 passes through a relay lens 56, the optical axis is changed at a right angle by a reflection mirror 57 arranged at 45 degrees with respect to the optical axis, and passes through a field lens 58. Then, the light enters the liquid crystal light valve 62 for R light and illuminates it. In the case of this R light, as shown in FIG. 3B, a real image X of the emission end face of the rod integrator 44 is formed between the field lenses 53 and 54, and the real image X is formed on the liquid crystal light valve 58 by the relay lens 56. It will form an image. Since the same field lens is used as the field lenses 50, 59, 58, the field lens 5
The size of the real image X of the emission end face of the rod integrator 44 formed between the third and the third 54 is the same as the size of the image formed by the B and G lights on the transmissive liquid crystal light valves 60 and 61. That is, a real image having the same size as the liquid crystal light valves 60, 61, 62 is obtained. As shown in FIG. 3B, the real image X is secured by the field lenses 54 and 58 for telecentricity, and the relay lens 56 forms an image of the same size on the liquid crystal light valve 62. In this way, the R optical system has a longer optical path length than the other B and G optical systems, but once the real image X
Transmissive liquid crystal light valve 62 with relay system after connecting
, The utilization efficiency of R light is improved.

The transmission type liquid crystal light valves 60, 61 and 62 for the respective color lights which are telecentricly illuminated have the same functions as those described in the first embodiment, and the transmitted light modulated by the image signal for each color. Are emitted from the transmissive liquid crystal light valves 60, 61 and 62, respectively. The modulated color lights transmitted through the transmissive liquid crystal light valves 60, 61, 62 are transmitted through the transmissive liquid crystal light valves 28, 2 respectively.
Since the reference numerals 9 and 30 are arranged substantially parallel to the side surfaces of the dichroic prism 63 as the color combining optical system, they are incident on the dichroic prism 63. The dichroic prism 63 has an R-light reflection dichroic film 65 and a B-light reflection dichroic film 64 arranged in an X-shape inside, and color-combines the incident color-modulated lights. That is, the modulated light of the incident B light is reflected by the B light reflecting dichroic film 64 and is incident on the R light.
The modulated light of the light is reflected by the R light reflecting dichroic film 65, and the modulated light of the incident G light is dichroic films 64 and 6.
5 are transmitted, and these are color-synthesized and emitted from the cross dichroic prism 63. Then, the light emitted from the cross dichroic prism 63 after the color combination is
It is projected on a screen (not shown) by a projection lens 66 forming a telecentric optical system.

Also in this embodiment, the light emitted from the light source 41 is polarized and separated into two polarized lights of P-polarized light and S-polarized light, and each of the transmissive liquid crystal light valves 60, 61, 62.
Since only one of the light beams is incident on the polarized light component, the polarization component absorbed by the incident side polarization plates of the transmissive liquid crystal light valves 60, 61, 62 is substantially the same as in the first embodiment described above. The heat generation is greatly reduced.

In this embodiment, the light source 41 is
An elliptic mirror 43 and a lamp 42 arranged at the position of the first focal point of the elliptic mirror 43 for emitting light having color light components of three primary colors.
And the rod integrator 44 whose end is arranged at the position of the second focal point of the elliptical mirror 43, the emission end face of the rod integrator 44 becomes substantially equivalent to a surface light source with uniform brightness. Therefore, as described above, by forming the image X of the emission end face of the rod integrator 44 on the transmissive liquid crystal light valves 60, 61, 62, light is incident on the transmissive liquid crystal light valves 60, 61, 62. The illumination can be performed by the critical illumination method, and the light utilization efficiency of the light from the light source can be improved.

Further, in this embodiment, the transmissive liquid crystal light valves 60, 61 and 62 and the dichroic prism 63 are arranged at positions where the principal ray determined by the aperture stop 66a of the projection lens 66 has telecentricity. Therefore, the transmissive liquid crystal light valves 60, 61, 6
The incident light to 2 is the transmissive liquid crystal light valve 60, 6
Since the light enters the light beams 1 and 62 substantially vertically, the image quality can be improved.

Further, in this embodiment, the relay / field lens system 45, 47, 50, 5 as described above is used.
By adopting 9, 53, 54, 58, the light source 41
To the liquid crystal light valves 60, 61, and 62 for the respective colors, it is possible to eliminate waste of light source light utilization due to the difference in optical path length. Instead of such a relay / field lens system, for example, each illumination optical system for the transmission type liquid crystal light valves 60 and 61 for B light and G light is constituted by two illumination lenses, and The rear focus of the illumination lens and the front focus of the illumination lens on the transmissive liquid crystal light valve side may be aligned. In this case, the illumination optical system for the transmissive liquid crystal light valve 62 for R light may be configured by using a plurality of such sets of illumination lenses.

Also in this embodiment, the half-wave plate 51 is removed, or the half-wave plate 51 is removed and the transmissive liquid crystal light valve is used, as in the first embodiment. A half-wave plate is arranged in front of 61 and 62, or a half-wave plate is arranged in front of transmissive liquid crystal light valves 61 and 62 without removing half-wave plate 51. It goes without saying that such a modification can be performed.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

For example, although the color separation optical system is constituted by a dichroic mirror in each of the above-mentioned embodiments, other color separation optical systems may be used in the present invention. That is, for example, in FIG. 1 or FIG. 2, the P-polarized light polarized and separated by the polarization beam splitters 22 and 48 is separated into only the B light by the R and G light cut color filters, and the mirrors 23 and 49 are normally reflected. It can be used as a mirror. In addition, in FIG. 1 or FIG.
Light may be cut by an R light cut filter, and the dichroic mirrors 25 and 55 may be ordinary reflection mirrors.
In that case, it is preferable that the cut filter is arranged perpendicular to the optical axis. This is because the cut filter has better performance.

[0047]

According to the present invention, it is possible to significantly reduce the polarization component absorbed in the transmissive liquid crystal light valve and to significantly reduce the heat generation in the transmissive liquid crystal light valve.

Further, according to some aspects of the present invention, it is possible to obtain an effect that the light utilization efficiency of the light source light is improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a projection display device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a projection display device according to a second embodiment of the present invention.

FIG. 3 is a chief ray diagram schematically showing the appearance of a chief ray of the projection display apparatus shown in FIG.

FIG. 4 is a schematic configuration diagram showing a conventional projection display device.

[Explanation of symbols]

21, 41 Light source 22, 48 Polarizing beam splitter 28, 29, 30, 60, 61, 62 Transmissive liquid crystal light valve 23, 24, 25, 49, 52, 55 Dichroic mirror 27, 51 1/2 wavelength plate 31, 63 Dichroic prism 34,66 Projection lens 34a, 66a Aperture stop 42 Lamp 43 Elliptical mirror 44 Rod integrator 45, 50, 53, 54, 58, 59 Field lens 47, 56 Relay lens

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03B 33/12 G03B 33/12 H04N 9/31 H04N 9/31 C

Claims (6)

[Claims] 1. A light source that emits light having color light components of three primary colors, a polarization beam splitter that splits the light emitted from the light source into two polarized lights having different polarization states, and a polarization beam splitter that polarizes the light. One of the three primary colors is obtained by color-separating one of the separated two polarized lights.
A first color separation optical system for obtaining two color lights, and a second color for obtaining the remaining two color lights of the color lights of the three primary colors by color-separating the other of the polarization-separated two polarized lights A separation optical system and three transmissive liquid crystal light valves provided for each color, wherein the one color light obtained from the first color separation optical system and the second color separation optical system Three transmissive liquid crystal light valves into which the obtained two color lights are respectively incident, and a color synthesizing optical system that color-synthesizes the transmitted light of the respective colors modulated by transmitting through the three transmissive liquid crystal light valves. A projection optical system for projecting transmitted light of each color that has been color-synthesized by the color synthesizing optical system; 2. A half-wave plate is arranged between at least one transmission liquid crystal light valve of the three transmission liquid crystal light valves and the polarization beam splitter. The projection display device described. 3. An elliptical mirror, a lamp for emitting light having color light components of three primary colors arranged at a position of a first focal point of the elliptic mirror, and an end portion thereof arranged at a position of a second focal point of the elliptic mirror. A light source having a rod integrator, a polarization beam splitter that polarizes and separates the light emitted from the light source into two polarized lights having different polarization states, and one of the two polarized lights that are polarized and separated by the polarization beam splitter. One of the three primary colors is obtained by color separation of one
A first color separation optical system for obtaining two color lights, and a second color for obtaining the remaining two color lights of the color lights of the three primary colors by color-separating the other of the polarization-separated two polarized lights A separation optical system and three transmissive liquid crystal light valves provided for each color, wherein the one color light obtained from the first color separation optical system and the second color separation optical system Three transmissive liquid crystal light valves into which the obtained two color lights are respectively incident, and a color synthesizing optical system that color-synthesizes the transmitted light of the respective colors modulated by transmitting through the three transmissive liquid crystal light valves. A projection optical system for projecting transmitted light of each color that has been color-synthesized by the color synthesizing optical system; 4. A half-wave plate is arranged between at least one transmissive liquid crystal light valve of the three transmissive liquid crystal light valves and the polarization beam splitter. The projection display device described. 5. The projection optical system has an aperture stop, and the three transmissive liquid crystal light valves and the color combining optical system are arranged at positions where a chief ray determined by the aperture stop has telecentricity. The projection type display device according to claim 3 or 4, characterized in that. 6. A first field lens and a first relay lens are arranged between the exit end of the rod integrator and the polarization beam splitter in this order from the exit end side of the rod integrator, and the first field lens and the first relay lens are arranged in this order from the exit end side of the rod integrator. A second field lens is disposed between the transmission type liquid crystal light valve on which the one color light obtained by the color separation optical system is incident and the polarization beam splitter, and the second field lens is obtained by the second color separation optical system. In addition, between the transmission type liquid crystal light valve on which one of the two color lights enters and the polarization beam splitter, the second
Of the two color lights obtained by the second color separation optical system by disposing a third field lens at a position where the other color light of the two color lights obtained by the second color separation optical system is not involved. Between the transmissive liquid crystal light valve on which the other color light is incident and the polarization beam splitter, the second
The fourth field lens, the fifth field lens, the second relay lens and the sixth field lens are arranged at positions where one color light of the two color lights obtained by the color separation optical system is not involved. 6. A real image of the exit end of the rod integrator is formed between the fourth field lens and the fifth field lens, arranged in this order from the beam splitter side. The projection type display device according to claim 1.