JP4617858B2 - projector - Google Patents

Description

  The present invention relates to a projector.

As a liquid crystal projector, a three-plate type liquid crystal projector using three liquid crystal panels is known. The three-plate type liquid crystal projector includes a light source, a color separation light guide optical system that separates light emitted from the light source into three color lights, three liquid crystal panels that respectively modulate the separated three color lights, and each liquid crystal A color combining prism such as a cross dichroic prism that combines color light that has been modulated by each of the three liquid crystal panels and then passed through the polarizing plate, and a color combining prism. A projection optical system for projecting the combined light. Here, among the pair of polarizing plates arranged before and after each liquid crystal panel, the polarizing plate arranged on the light source side of the liquid crystal panel is used as the incident side polarizing plate, and the polarizing plate arranged on the cross dichroic prism side of the liquid crystal panel is used. It will be referred to as an emission side polarizing plate.

In such a three-plate type liquid crystal projector, heat is generated when the incident-side polarizing plate and the emitting-side polarizing plate absorb light. These polarizing plates are generally vulnerable to heat, and when they are deteriorated by heat, the polarization selection characteristics are lowered and the image quality of the projected image is lowered. Of these, the exit-side polarizing plate plays an important role in finally determining the image quality of the projected image, so it is necessary to suppress the temperature rise in particular.
In recent years, a liquid crystal projector uses a polarization conversion element that converts random polarized light emitted from a light source into polarized light having substantially the same polarization direction. If such a polarization conversion element is used, light having substantially the same polarization direction is incident on the incident-side polarizing plate, so that the amount of heat generated in the incident-side polarizing plate can be suppressed to some extent.
However, since light that has been modulated by the liquid crystal panel and whose polarization direction has changed in various ways is incident on the exit-side polarizing plate, in a liquid crystal projector that employs a polarization conversion element, the temperature of the exit-side polarizing plate is It will be significantly higher than the temperature. Therefore, in the liquid crystal projector employing the polarization conversion element, it is particularly important to suppress the temperature rise of the exit side polarizing plate.

FIG. 9 is a diagram for explaining a conventional projector proposed for solving such a problem. In the conventional projector 900, the exit side polarizing plates 943R, 94
Between 3G and 943B and the cross dichroic prism 500, liquid cooling means 950R, 950G and 950B filled with a cooling liquid are provided.
For this reason, according to the conventional projector 900, the exit side polarizing plates 943R, 943G, 9
Since the heat generated in 43B can be effectively released to the liquid cooling means 950R, 950G, and 950B, it is possible to effectively suppress the temperature rise of the exit side polarizing plates 943R, 943G, and 943B ( For example, see Patent Document 1.)

JP 2002-287244 A (FIG. 1)

However, in the conventional projector 900, the exit side polarizing plates 943R and 943 are used.
The heat generation in G and 943B cannot be prevented. For this reason, if the brightness of the projector further increases, significant heat generation will occur in the exit side polarizing plate,
Even with such a liquid cooling means, there is a problem that it is not easy to effectively suppress the temperature rise of the exit side polarizing plate. Further, in the conventional projector 900, the liquid crystal panel 9
Since polarized light that is modulated by 41R, 941G, and 941B and should not be allowed to proceed to the projection optical system 600 is absorbed by the exit-side polarizing plates 943R, 943G, and 943B, the polarized light is effectively used. There was also a problem that it was not possible.

Therefore, the present invention has been made to solve such a problem, and by suppressing the heat generation itself in the exit side polarizing plate, the temperature rise of the exit side polarizing plate is effectively suppressed, and as a result, the brightness is increased. It is a first object of the present invention to provide an easy projector. It is a second object of the present invention to provide a projector capable of effectively using polarized light which is modulated by a liquid crystal panel and should not be allowed to proceed to the projection optical system.

The projector of the present invention includes an illumination device, a color separation light guide optical system that separates the illumination light beam from the illumination device into a plurality of color lights, and the illumination light beam from the color separation light guide optical system is modulated according to image information A plurality of liquid crystal panels, a cross dichroic prism that combines light beams modulated by the plurality of liquid crystal panels, a projection optical system that projects light synthesized by the cross dichroic prism, the illumination device, and the color separation guide A projector including a housing that houses an optical optical system, the plurality of liquid crystal panels, and the cross dichroic prism;
A plurality of reflective polarizing plates provided between the plurality of liquid crystal panels and the cross dichroic prism and arranged to reflect polarized light that should be prohibited from traveling to the projection optical system out of the optical path; And a display panel provided on the body, wherein the display panel receives and reflects light reflected by the plurality of reflective polarizing plates.

For this reason, according to the projector of the present invention, the polarized light transmitted through the reflective polarizing plate among the polarized light modulated by the liquid crystal panel is projected by the projection optical system and projected onto a projection surface such as a screen. Of the polarized light modulated by the liquid crystal panel, the polarized light that should be prohibited from proceeding to the projection optical system is reflected by the reflective polarizing plate and is out of the optical path through which the light forming the image of the optical system constituting the projector passes. To escape. For this reason, unlike the case where a light absorption type polarizing plate is used as in the prior art, the heat generation itself in the exit side polarizing plate is effectively suppressed. As a result, the temperature rise of the exit-side polarizing plate is effectively suppressed, and as a result, the projector can be easily increased in brightness, and the first object of the present invention is achieved.

Further, according to the projector of the present invention, the polarized light that should be prohibited from traveling to the projection optical system is reflected off the optical path by the reflective polarizing plate, and the display plate provided in the housing transmits the polarized light. It is arranged to receive and shine. For this reason, it becomes a projector which can aim at the effective use of the polarized light which should prohibit the progress to a projection optical system among the polarized light modulated by the liquid crystal panel, and the 2nd objective of this invention is achieved.

In this case, when the projected image is bright, the polarized light that should be prohibited from proceeding to the projection optical system is dark, so the amount of light emitted from the display board is also small. Since the board is indirectly illuminated, the user can easily visually recognize the information on the display board.
On the other hand, when the projected image is dark, the polarized light that should be prohibited from proceeding to the projection optical system is bright, and the amount of light emitted from the display panel is also large. For this reason, the user can easily visually recognize the information on the display board.

In the projector according to the aspect of the invention, it is preferable that the reflective polarizing plate is a polarization separation prism having a polarization separation layer that reflects polarized light that should be prohibited from traveling to the projection optical system to the outside of the optical path. The light incident surface of the polarization separation prism preferably reflects light reflected by the polarization separation layer out of the optical path. Furthermore, in this case, it is preferable to use a polarization beam splitter in which the angle between the light incident surface and the polarization separation surface is set in the range of 20 ° to 40 ° as the polarization separation prism type reflection polarizing plate.

With this configuration, the polarized light reflected by the polarization separation surface is emitted as it is from the side surface of the polarization beam splitter as the polarization separation prism type reflective polarizing plate, or once the light incidence surface of the polarization beam splitter After being reflected by the light beam, it is emitted from the side surface of the polarization beam splitter. In this case, since the light is incident on the light incident surface of the polarization beam splitter, the stray light level can be effectively reduced.

From the viewpoints described above and from the viewpoint of shortening the length along the optical path of the reflective polarizing plate, a polarizing beam splitter in which the angle between the light incident surface and the polarization separation surface is set in the range of 25 ° to 30 °. More preferably, it is used.

In the projector according to the aspect of the invention, it is preferable that the reflective polarizing plate is a diffraction grating type reflective polarizing plate. In this case, a so-called wire grid type reflection polarizing plate in which a large number of gratings made of an inorganic material are regularly formed on the surface of a substrate such as glass is used as the diffraction grating type reflection polarizing plate. preferable.

With this configuration, it is possible to configure a reflective polarizing plate with extremely high heat resistance, and thus it is possible to provide a projector that can easily achieve higher luminance.

In this case as well, from the viewpoint of effectively reflecting the reflected light out of the optical path and reducing the stray light level, a polarization beam splitter using a wire grid type reflection polarizing plate as a polarization separation surface is used. Is preferred.
From the above viewpoint and the viewpoint of shortening the length along the optical path of the reflective polarizing plate, a polarizing beam splitter in which the angle formed by the light incident surface and the polarization separation surface is set in a range of 20 ° to 40 ° is provided. It is preferable to use a polarizing beam splitter in which the angle between the light incident surface and the polarization separation surface is set in a range of 25 ° to 30 °. In this case, it is more preferable that the light incident surface of the polarization beam splitter reflects the light reflected by the polarization separation surface out of the optical path.

In the projector according to the aspect of the invention, it is preferable that a light guide path that guides light reflected by the reflective polarizing plate to the display plate is provided between the reflective polarizing plate and the display plate.

By configuring in this way, the light reflected by the reflective polarizing plate is efficiently guided to the display panel, so that the light reflected by the reflective polarizing plate is prevented from leaking out of the optical path. As a result, the stray light level of the projector can be reduced.

In the projector according to the aspect of the invention, it is preferable that a dimming unit that absorbs light reflected by the reflective polarizing plate is provided between the reflective polarizing plate and the display plate.

Depending on the degree of modulation in the liquid crystal panel, most of the light passing through the liquid crystal panel may be reflected by the reflective polarizing plate. In such a case, if all of the reflected light is guided to the display board, the intensity of the light emitted from the display board is too strong, resulting in dazzling or obstructing the viewing of the projected image. There is also.
However, even in such a case, by configuring as described above, the reflected light is absorbed by the dimming means, so that the intensity of the light emitted from the display board can be appropriately reduced. It is possible to suppress dazzling or obstructing the viewing of the projected image.

In the projector according to the aspect of the invention, a light amount adjusting unit that adjusts a ratio at which light reflected by the reflective polarizing plate is guided to the display plate is provided between the reflective polarizing plate and the display plate. Preferably it is.

As described above, if all the reflected light is guided to the display board, the intensity of the light emitted from the display board is too strong, and it may be dazzling or disturbing the viewing of the projected image. is there.
However, even in such a case, by configuring as described above, the reflected light is appropriately adjusted in light amount by the optical adjustment means, and thus the intensity of the light emitted from the display board can be appropriately reduced. It is possible to suppress dazzling or obstructing the viewing of the projected image. In this case, the degree of modulation of the liquid crystal panel (the amount of light guided to the display plate is increased even when a bright projection image is displayed. The amount of light guided to the display plate also when a dark projection image is displayed. ) And surrounding dark environment (increase the amount of light guided to the display board even when the surroundings are bright. Reduce the amount of light guided to the display board even when the surroundings are dark) and use Adjust the amount of light according to the environment (increase the amount of light guided to the display plate when it is necessary to see the display plate. Decrease the amount of light guided to the display plate when it is not necessary to see the display plate). Thus, the display board can be used effectively according to the purpose of use.

In the projector according to the aspect of the invention, it is preferable that the display plate is a transmissive display device.

By configuring in this way, it is possible to display an arbitrary display on the display board,
Various information and messages can be transmitted to the user. In this case,
It is possible to adjust the transmittance of the display device according to the modulation degree of the liquid crystal panel, the surrounding dark environment, the usage environment, etc., and thus the display light quantity, and the display board can be effectively used according to the purpose of use. It becomes possible to use.

  The projector of the present invention will be described below based on the embodiments shown in the drawings.

Embodiment 1
FIG. 1 is a diagram illustrating an optical system of a projector 1000 according to the first embodiment. FIG.
Is a top view of the optical system of the projector 1000, and FIG. 1 (b) is a symbol a shown in FIG. 1 (a).
It is a cross-sectional view as viewed from the side along the _{one to} code a _3. FIG. 2 is a diagram illustrating a main part of the projector 1000 according to the first embodiment. FIG. 2A is a top view, and FIG. 2B is FIG.
It is a sectional view viewed from the side along the code b _{1 ~} code b ₃ shown in. FIG. 3 is a diagram for explaining functions of the projector 1000 according to the first embodiment. FIG. 3A is a top view of the projector 1000, and FIG. 3B is an enlarged view of a portion indicated by reference numeral A in FIG.

As shown in FIG. 1, a projector 1000 according to the first embodiment includes an illumination device 100, a color separation light guide optical system 200 that separates an illumination light beam from the illumination device 100 into a plurality of color lights, and a color separation light guide optical system. Three liquid crystal devices 400R that modulate the illumination light beam from 200 according to image information,
400G and 400B (see FIG. 2), a cross dichroic prism 500 that combines light beams modulated by the three liquid crystal devices 400R, 400G, and 400B, and a projection optical system 600 that projects light combined by the cross dichroic prism 500. It is a projector provided with. Note that these optical systems are arranged in the housing 700. In addition, FIG.
As shown in b), a light blocking member 720 for absorbing stray light is disposed above the liquid crystal devices 400R, 400G, 400B and the cross dichroic prism 500 so as to avoid the display plate 710.

As shown in FIG. 1, the illumination device 100 includes a light source device 110 that emits an illumination light beam that is substantially parallel to the illuminated region side, and a plurality of light sources that are used to divide the illumination light beam emitted from the light source device 110 into a plurality of partial light beams. A first lens array 120 having a first small lens, a second lens array 130 having a plurality of second small lenses corresponding to the plurality of first small lenses of the first lens array 120,
A polarization conversion element 140 that emits an illumination light beam having a non-uniform polarization direction emitted from the light source device 110 so as to be aligned with one type of linearly polarized light, and each partial light beam emitted from the polarization conversion element 140 are superimposed on the illuminated region. And a superimposing lens 150 for this purpose.

As illustrated in FIG. 1, the light source device 110 includes an ellipsoidal reflector 114, a light emitting tube 112 having a light emission center near the first focal point of the ellipsoidal reflector 114, and a focused light reflected by the ellipsoidal reflector 114. And a collimating lens 118 for converting light. The arc tube 112 is provided with an auxiliary mirror 116 as a reflecting means for reflecting the light emitted from the arc tube 112 toward the illuminated area toward the ellipsoidal reflector 114.
The first lens array 120 has a configuration in which small lenses having a substantially rectangular outline when viewed from the z-axis direction are arranged in a plane perpendicular to the z-axis. Each small lens of the first lens array 120 is
The light beam emitted from the light source device 110 is divided into a plurality of partial light beams. First lens array 12
The contour shape of each small lens of 0 is set so as to be substantially similar to the shape of the image forming area of the liquid crystal devices 400R, 400G, and 400B. For example, the liquid crystal devices 400R, 400G,
If the aspect ratio (ratio of horizontal and vertical dimensions) of the image forming area of 400B is 4: 3,
The aspect ratio of each small lens is 4: 3.
The second lens array 130 has substantially the same configuration as the first lens array 120, and has a configuration in which small lenses are arranged in a plane perpendicular to the z axis. The second lens array 130, together with the superimposing lens 150, displays images of the small lenses of the first lens array 120 in the liquid crystal devices 400R, 4R.
It has a function of forming an image on 00G and 400B.

The color separation light guide optical system 200 separates the illumination light beam emitted from the illumination device 100 into a plurality of color lights, and guides each color light to the liquid crystal devices 400R, 400G, and 400B.
The first dichroic mirror 210 reflects red light and transmits green light and blue light. The red light reflected by the first dichroic mirror 210 is reflected by the reflection mirror 2.
30 is further reflected, passes through the field lens 280R, and the liquid crystal device 400 for red light.
Illuminate R.
The field lens 280R condenses the plurality of partial light beams from the superimposing lens 150 so as to illuminate the liquid crystal device 400R for red light. Usually, each partial light beam is set to be a substantially parallel light beam. The field lenses 280G and 280B disposed in front of the other liquid crystal devices 400G and 400B are configured similarly to the field lens 280R.
The green light that has passed through the first dichroic mirror 210 is reflected by the second dichroic mirror 220, passes through the field lens 280G, and the liquid crystal device 40 for green light.
Illuminate 0G. On the other hand, the blue light that has passed through the first dichroic mirror 210 is transmitted through the second dichroic mirror 220, and the relay lens 260 and the incident-side reflection mirror 240.
The liquid crystal device 400B for blue light is illuminated through the relay lens 270, the reflection mirror 250 on the emission side, and the field lens 280B. In addition, relay lenses 260 and 27 are used for blue light.
0 and reflecting mirrors 240 and 250 are used because the optical path length of the blue light is longer than the optical path lengths of the other color lights, so that the use efficiency of the light due to the divergence of the light is prevented. It is. That is, the partial light beam incident on the relay lens 260 is directly used as the field lens 2.
This is to tell 80B. The relay lenses 260 and 270 and the reflection mirror 240,
Although 250 is configured to pass blue light of the three color lights, it may be configured to transmit other color light such as red light.

The liquid crystal devices 400R, 400G, and 400B convert the color light incident on the respective light incident surfaces into light corresponding to the corresponding image signal, and emit the converted light as image light. As shown in FIG. 2A, the liquid crystal devices 400R, 400G, and 400B include incident-side polarizing plates 420R, 420G, and 420B, liquid crystal panels 410R, 410G, and 410B, and reflection-type polarizing plates 430R and 430G as emission-side polarizing plates. , 430B.
The liquid crystal panels 410R, 410G, and 410B are a pair of transparent glass substrates in which a liquid crystal that is an electro-optical material is hermetically sealed. For example, a polysilicon TFT is used as a switching element and incident according to given image information. The polarization direction of one type of linearly polarized light emitted from the side polarizing plates 420R, 420G, and 420B is modulated.

The cross dichroic prism 500 includes reflective polarizing plates 430R, 430G, and 430B.
This is an optical element that forms a color image by synthesizing optical images modulated for each color light emitted from the light source. The cross dichroic prism 500 has a substantially square shape in plan view in which four right-angle prisms are bonded together, and a dielectric multilayer film is formed on a substantially X-shaped interface in which the right-angle prisms are bonded together. The dielectric multilayer film formed at one interface having a substantially X shape reflects red light, and the dielectric multilayer film formed at the other interface reflects blue light. The red and blue light is reflected by the dielectric multilayer film and aligned with the traveling direction of the green light, so that the three color lights are synthesized.

The color image emitted from the cross dichroic prism 500 is output from the projection optical system 600.
Is enlarged and projected to form a large screen image on the screen SCR.

The projector 1000 according to the first embodiment includes the liquid crystal panels 410R, 410G, 410.
Three reflective polarizing plates 430R and 430G provided between B and the cross dichroic prism 500 and disposed so as to reflect polarized light that should be prohibited from traveling to the projection optical system 600 to the upper side of the housing 700. , 430B and these three reflective polarizing plates 430R, 430G, 4
And a display panel 710 that receives the light reflected by 30B and shines.

Therefore, according to the projector 1000 according to the first embodiment, the liquid crystal panels 410R, 4
Of the polarized light modulated by 10G and 410B, the reflective polarizing plates 430R, 430G and 430B
The polarized light that has passed through is projected by the projection optical system 600 and projected onto a projection surface such as a screen SCR, while the polarized light modulated by the liquid crystal panels 410R, 410G, and 410B proceeds to the projection optical system 600. The polarized light to be prohibited is a reflection type polarizing plate 430R, 430G, 430B.
And escapes out of the optical path through which the light forming the image of the optical system constituting the projector 1000 passes. For this reason, unlike the conventional case of using a light absorption type polarizing plate, the heat generation itself in the reflection type polarizing plates 430R, 430G, and 430B is effectively suppressed. As a result, the temperature increase of the reflective polarizing plates 430R, 430G, and 430B is effectively suppressed, and as a result, the projector can be easily increased in luminance.

Further, according to the projector according to the first embodiment, the polarized light that should be prohibited from traveling to the projection optical system 600 is out of the optical path by the reflective polarizing plates 430R, 430G, and 430B (see FIG. 1B). The display panel 71 provided on the casing 700 is reflected on the upper side of the casing 700.
0 is arranged to receive the polarized light and shine. For this reason, the liquid crystal panels 410R, 4
Of the polarized light modulated by 10G and 410B, a projector capable of effectively utilizing polarized light that should be prohibited from proceeding to the projection optical system 600 is obtained. Note that a diffusion plate 712 is provided so that external light does not penetrate the display plate 710 from the outside of the housing 700 and enter the housing 700.

In this case, when the projected image is bright, the polarized light that should be prohibited from proceeding to the projection optical system 600 is dark, and thus the amount of light emitted from the display plate 710 is small. In this case, from the screen SCR or the like. Since the display board 710 is indirectly illuminated by the light, the user can easily visually recognize the information on the display board 710.
On the other hand, when the projected image is dark, the polarized light that should be prohibited from traveling to the projection optical system 600 is bright, and the amount of light emitted from the display plate 710 is also large. For this reason, the user can easily visually recognize the information on the display board 710.

As shown in FIG. 3, the display board 710 includes “POWER”, “MENU”, “MOD”.
E ", other characters, symbols, patterns, etc. can be preferably used. In this case, since these characters, symbols, patterns, and the like can be illuminated using red light, green light, and blue light, various and diverse displays can be performed.

In the projector 1000 according to the first embodiment, the reflective polarizing plates 430R and 430G.
, 430B is a polarization separation prism having a polarization separation layer that reflects polarized light that should be prohibited from traveling to the projection optical system 600 out of the optical path. Further, the light incident surface of the polarization separation prism type reflective polarizing plate is configured to reflect the light reflected by the polarization separation layer out of the optical path. Furthermore, this polarization separation prism type reflection polarizing plate has an angle of 2 between the light incident surface and the polarization separation surface.
It is a polarization beam splitter set in a range of 0 ° to 40 °.

Therefore, according to the projector 1000 according to the first embodiment, the polarized light reflected by the polarization separation surface is emitted as it is from the side surfaces of the reflective polarizing plates 430R, 430G, and 430B, or once reflected by the light incident surface. Then, the light is emitted from the side surfaces of the reflective polarizing plates 430R, 430G, and 430B. In this case, since light is totally reflected on the light incident surfaces of the reflective polarizing plates 430R, 430G, and 430B, the stray light level can be effectively reduced.

In addition, it is more preferable to use a polarization beam splitter in which the angle between the light incident surface and the polarization separation surface is set in the range of 25 ° to 30 ° as the reflection type polarizing plates 430R, 430G, and 430B. In this case, as described above, the stray light level can be effectively reduced, and the length of the reflective polarizing plate along the optical path can be shortened.
Such reflective polarizing plates 430R, 430G, and 430B can be obtained from Mostex.

In the projector 1000 according to the first embodiment, as shown in FIG. 2B, the reflective polarizing plate 430R is interposed between the reflective polarizing plates 430R, 430G, and 430B and the display plate 710.
, 430G, 430B, a light guide path 722 for guiding the light reflected to the display plate 710 is provided.

Therefore, according to the projector 1000 according to the first embodiment, the reflective polarizing plate 430R,
Since the light reflected by 430G and 430B is efficiently guided to the display plate 710, the light reflected by the reflective polarizing plates 430R, 430G and 430B is prevented from leaking out of the optical path. Thus, the stray light level of the projector 1000 can be reduced.

[Embodiment 2]
FIG. 4 is a diagram illustrating a main part of the projector 1002 according to the second embodiment. In FIG. 4, the same members as those shown in FIG. 2B are denoted by the same reference numerals, and detailed description thereof is omitted.

A projector 1002 (not shown) according to the second embodiment has basically the same configuration as the projector 1000 according to the first embodiment, but as shown in FIG. Between the polarizing plates 430G and 430B and the display plate 710, the reflective polarizing plates 430R and 43
The difference is that a light reducing means 730 for absorbing light reflected by 0G and 430B is provided.

As described above, the projector 1002 according to the second embodiment includes the reflective polarizing plates 430R and 43.
Unlike the projector 1000 according to the first embodiment, the liquid crystal panels 410R and 41R are different from the projector 1000 according to the first embodiment in that a dimming unit 730 is provided between the 0G and 430B and the display plate 710.
0G, 410B and the cross dichroic prism 500, and the projection optical system 6
Three reflective polarizing plates 430R, 430G, and 430B arranged to reflect the polarized light that should be prohibited from proceeding to 00 to the upper side of the housing 700, and these three reflective polarizing plates 430R,
In the point provided with the display board 710 which receives and reflects the light reflected by 430G and 430B,
This is the same as the projector 100 according to the first embodiment. For this reason, in the projector 1002 according to the second embodiment, similarly to the projector 1000 according to the first embodiment, the heat generation itself in the reflective polarizing plates 430R, 430G, and 430B is effectively suppressed. As a result, the temperature increase of the reflective polarizing plates 430R, 430G, and 430B is effectively suppressed, and as a result, the projector can be easily increased in luminance.

Further, according to the projector 1002 according to the second embodiment, the polarized light that should be prohibited from traveling to the projection optical system 600 is the reflective polarizing plates 430R, 430G, and 430B as shown in FIG. The display plate 710 provided in the housing 700 is arranged so as to receive the polarized light and shine. For this reason, the projector 1 according to the first embodiment.
As in the case of 000, it becomes a projector capable of effectively using polarized light that should be prohibited from proceeding to the projection optical system 600 among polarized light modulated by the liquid crystal panels 410R, 410G, and 410B.

In the projector 1002 according to the second embodiment, as described above, the reflective polarizing plate 4
Between the 30R, 430G, and 430B and the display plate 710, the reflective polarizing plates 4300R and 43
Dimming means 730 for absorbing light reflected by 0G and 430B is provided.

Depending on the degree of modulation in the liquid crystal panel, most of the light passing through the liquid crystal panel may be reflected by the reflective polarizing plate. In such a case, if all of the reflected light is guided to the display board, the intensity of the light emitted from the display board is too strong, which may cause dazzling or obstruct the viewing of the projected image. There is also.
However, even in such a case, according to the projector 1002 according to the second embodiment, the reflected light is absorbed by the dimming unit 730, so that the intensity of the light emitted from the display board 710 is appropriately reduced. It is possible to suppress dazzling or obstructing the viewing of the projected image.

[Embodiment 3]
FIG. 5 is a diagram illustrating a main part of the projector 1004 according to the third embodiment. In FIG. 5, the same members as those shown in FIG. 2B are denoted by the same reference numerals, and detailed description thereof is omitted.

A projector 1004 (not shown) according to the third embodiment has basically the same configuration as that of the projector 1000 according to the first embodiment. However, as shown in FIG. Between the polarizing plates 430G and 430B and the display plate 710, the reflective polarizing plates 430R and 43
Light amount adjusting means 7 for adjusting the ratio at which the light reflected by 0G and 430B is guided to the display panel 710
The difference is that 40 is provided.

As described above, the projector 1004 according to the third embodiment includes the reflective polarizing plates 430R and 43.
The projector is different from the projector 1000 according to the first embodiment in that a light amount adjusting unit 740 is provided between the 0G, 430B and the display plate 710, but otherwise the projector and the projector according to the first embodiment are different from those in the first embodiment. Since it has the same configuration, the projector 1 according to the first embodiment.
000 as it is.

In the projector 1004 according to the third embodiment, the reflective polarizing plates 430R and 430G.
, 430B and the display plate 710 are provided with a light amount adjusting means 740 for adjusting the ratio of the light reflected by the reflective polarizing plates 430R, 430G, 430B to the display plate 710.

Depending on the degree of modulation in the liquid crystal panel, most of the light passing through the liquid crystal panel may be reflected by the reflective polarizing plate. In such a case, if all of the reflected light is guided to the display board, the intensity of the light emitted from the display board is too strong, resulting in dazzling or obstructing the viewing of the projected image. There is also.
However, even in such a case, according to the projector 1004 according to the third embodiment, the light amount of the reflected light is appropriately adjusted by the light amount adjusting unit 740.
The intensity of the light emitted from 10 can be appropriately reduced, and it can be prevented from being dazzled or obstructing the viewing of the projected image. In this case, the liquid crystal panel 410
R, 410G, 410B modulation degree (the amount of light guided to the display plate 710 is increased even when a bright projection image is displayed. The amount of light guided to the display plate 710 also when a dark projection image is displayed. And the surrounding dark environment (increase the amount of light guided to the display plate 710 even when the surrounding is bright. Reduce the amount of light guided to the display plate 710 even when the surrounding is dark). , In a usage environment (when the display plate 710 needs to be seen firmly, the amount of light guided to the display plate 710 is increased. When there is no need to see the display plate 710, the amount of light guided to the display plate 710 is reduced). Accordingly, the light amount can be adjusted, and the display board 710 can be used effectively according to the purpose of use.

[Embodiment 4]
FIG. 6 is a diagram illustrating a main part of the projector 1006 according to the fourth embodiment. In FIG. 6, the same members as those shown in FIG. 2B are denoted by the same reference numerals, and detailed description thereof is omitted.

A projector 1006 (not shown) according to the fourth embodiment has basically the same configuration as the projector 1000 according to the first embodiment, but as shown in FIG. 6, the projector according to the first embodiment. 1000 is different from the configuration of the reflective polarizing plate.
That is, in the projector 1006 according to the fourth embodiment, as the reflective polarizing plate,
Instead of the polarizing prism type reflective polarizing plate, the diffraction grating type reflective polarizing plates 432R, 432G
, 432B (only the reflective polarizing plate 432R is shown in FIG. 6). The diffraction grating type reflective polarizing plate is a so-called wire grid type reflective polarizing plate in which a large number of gratings made of an inorganic material are regularly formed on the surface of a substrate such as glass.

As described above, the projector 1006 according to the fourth embodiment is different from the projector 1000 according to the first embodiment in the configuration of the reflective polarizing plate, but is otherwise the same as the projector according to the first embodiment. Since it has a configuration, the projector 1 according to the first embodiment.
000 as it is.

In the projector 1006 according to the fourth embodiment, as described above, the diffraction grating type reflective polarizing plates 432R, 432G, and 432B are used as the reflective polarizing plates. And
A diffraction grating type reflective polarizing plate is a so-called wire grid type reflective polarizing plate in which a large number of gratings made of an inorganic material are regularly formed on the surface of a substrate such as glass.

For this reason, according to the projector 1006 according to the fourth embodiment, a reflective polarizing plate with extremely high heat resistance can be configured, so that it is possible to provide a projector with higher brightness.

[Embodiment 5]
FIG. 7 is a diagram illustrating a main part of the projector 1008 according to the fifth embodiment. In FIG. 7, the same members as those shown in FIG. 2B are denoted by the same reference numerals, and detailed description thereof is omitted.

A projector 1008 (not shown) according to the fifth embodiment has basically the same configuration as the projector 1000 according to the first embodiment, but as shown in FIG. 7, the projector according to the first embodiment. 1000 is different from the configuration of the reflective polarizing plate.

In other words, in the projector 1008 according to the fifth embodiment, from the viewpoint of effectively escaping the light reflected by the reflective polarizing plate out of the optical path and reducing the stray light level, the wire grid type reflective type is used as the reflective polarizing plate. Reflective polarizing plates 434R, 434G, and 434B (only the reflective polarizing plate 434R is shown in FIG. 7) made of a polarizing beam splitter using the polarizing plate as a polarization separation surface are used.

As described above, the projector 1008 according to the fifth embodiment is different from the projector 1000 according to the first embodiment in the configuration of the reflective polarizing plate, but is otherwise the same as the projector according to the first embodiment. Since it has a configuration, the projector 1 according to the first embodiment.
000 as it is.

In the projector 1008 according to the fifth embodiment, as described above, from the viewpoint of effectively escaping the light reflected by the reflective polarizing plate out of the optical path and reducing the stray light level, the wire grid type is used as the reflective polarizing plate. Reflective polarizing plates 434R, 434G, and 434B made of a polarizing beam splitter using the above-described reflective polarizing plate as a polarization separation surface are used. In this case,
Rather than bonding the wire grid layer directly to the glass prism, it is preferable to integrate the wire grid layer with the glass prism via an air layer.

For this reason, according to the projector 1008 according to the fifth embodiment, it is possible to configure a reflective polarizing plate with extremely high heat resistance, and thus it is possible to provide a projector with higher brightness.

The reflective polarizing plates 434R, 434G, and 434B are polarizing beam splitters in which the angle formed between the light incident surface and the polarization separation surface is set in the range of 25 ° to 30 °. For this reason, as described above, the stray light level can be effectively reduced, and the length of the reflective polarizing plate along the optical path can be shortened.

[Embodiment 6]
FIG. 8 is a diagram illustrating a main part of the projector 1010 according to the sixth embodiment. In FIG. 8, the same members as those shown in FIG. 2B are denoted by the same reference numerals, and detailed description thereof is omitted.

A projector 1010 (not shown) according to the sixth embodiment has basically the same configuration as the projector 1000 according to the first embodiment, but as shown in FIG. 8, the projector according to the first embodiment. The display panel is different from 1000.
That is, in the projector 1010 according to the sixth embodiment, the transmissive display device 750 is used as the display plate.

As described above, in the projector 1010 according to the sixth embodiment, the configuration of the display board is the same as in the first embodiment.
The projector 1000 according to the first embodiment is different from the projector 1000 according to the first embodiment, but has the same configuration as that of the projector according to the first embodiment.
It has the effect which has.

In the projector 1010 according to the sixth embodiment, as described above, as the display board,
A transmissive display device 750 is used.

For this reason, according to the projector 1010 according to the sixth embodiment, since it is possible to cause the display device 750 to perform arbitrary display, it is possible to transmit various information and messages to the user. Further, in this case, it is possible to adjust the transmittance in the display device 750 and thus the display light amount according to the modulation degree of the liquid crystal panels 410R, 410G, and 410B, the surrounding dark environment, the use environment, and the like. The display device 750 can be used effectively according to the purpose of use.

The projector of the present invention has been described based on the above embodiments. However, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the scope of the invention. For example, the following modifications are possible.

(1) The projectors 1000 to 1010 according to the above-described embodiments guide light reflected by the reflective polarizing plate to the display plate through a space, but the present invention is not limited to this. . A bundle of optical fibers can be guided to the display plate as a light guide path.

(2) In the projectors 1000 to 1010 of the above-described embodiments, a reflective polarizing plate is used as the exit-side polarizing plate, and light reflected by the reflective polarizing plate is guided to the display plate. The invention is not limited to this. A reflective polarizing plate can be used as the incident side polarizing plate, and the light reflected by the reflective polarizing plate can be guided to the display plate.

(3) The projector of each of the above embodiments is a transmissive projector, but the present invention is not limited to this. The present invention can also be applied to a reflection type projector. Here, “transmission type” means that an electro-optic modulation device as a light modulation means, such as a transmission type liquid crystal device, transmits light, and “reflection type” This means that an electro-optic modulation device as a light modulation means, such as a reflective liquid crystal device, is a type that reflects light. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

(4) Although the projector according to each of the above embodiments uses a liquid crystal device as an electro-optic modulation device, the present invention is not limited to this. In general, the electro-optic modulation device may be any device that modulates incident light in accordance with image information, and a micromirror light modulation device or the like may be used. For example, a DMD (digital micromirror device) (trademark of TI) can be used as the micromirror light modulator.

In addition, it goes without saying that the present invention can be applied to a front projection type projector that projects from the side that observes the projected image and a rear projection type projector that projects from the side opposite to the side that observes the projected image. .

FIG. 3 shows an optical system of the projector 1000 according to the first embodiment. FIG. 3 is a diagram illustrating a main part of the projector 1000 according to the first embodiment. FIG. 4 is a diagram for explaining functions of the projector 1000 according to the first embodiment. FIG. 10 is a diagram illustrating a main part of a projector 1002 according to a second embodiment. FIG. 10 is a diagram illustrating a main part of a projector 1004 according to a third embodiment. FIG. 10 is a diagram showing a main part of a projector 1006 according to a fourth embodiment. FIG. 10 shows a main part of a projector 1008 according to a fifth embodiment. FIG. 10 shows an optical system of a projector 1010 according to a sixth embodiment. The figure shown in order to demonstrate the conventional projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Illuminating device, 100ax ... Illumination optical axis, 110,910 ... Light source device, 112,912
... arc tube, 114, 914 ... ellipsoidal reflector, 116 ... auxiliary mirror, 118 ... collimating lens, 120 ... first lens array, 130 ... second lens array, 140 ... polarization conversion element,
150 ... Superimposing lens, 200 ... Color separation light guide optical system, 210, 220 ... Dichroic mirror, 230, 240, 250, 960 ... Reflection mirror, 260, 270 ... Relay lens, 2
80R, 280G, 280B ... Field lens, 400R, 400G, 400B ... Liquid crystal device, 410R, 410G, 410B, 941R, 941G, 941B ... Liquid crystal panel, 4
20R, 420G, 420B, 942R, 942G, 942B ... Incident-side polarizing plate, 430R
, 430G, 430B, 432R, 434R ... reflective polarizing plate, 500 ... cross dichroic prism, 600 ... projection optical system, 700 ... housing, 710 ... display plate, 710 ... diffuser plate,
720 ... Light shielding member, 722 ... Light guide path, 730 ... Dimming means, 740 ... Light quantity adjusting means, 750
... Display device, 900, 1000 ... Projector, 943R, 943G, 943B ... Ejection side polarizing plate, 950R, 950G, 950B ... Liquid cooling means

Claims (8)

A lighting device;
A color separation light guide optical system for separating an illumination light beam from the illumination device into a plurality of color lights;
A plurality of liquid crystal panels that modulate the illumination light flux from the color separation light guide optical system according to image information;
A cross dichroic prism that combines light beams modulated by the plurality of liquid crystal panels;
A projection optical system for projecting light synthesized by the cross dichroic prism;
A projector including a housing for housing the illumination device, the color separation light guide optical system, the plurality of liquid crystal panels, and the cross dichroic prism;
A plurality of reflective polarizing plates provided between the plurality of liquid crystal panels and the cross dichroic prism, and arranged to reflect polarized light that should be prohibited from proceeding to the projection optical system, out of the optical path;
Further comprising a display plate provided in the housing,
The projector is characterized in that the display panel receives and reflects light reflected by the plurality of reflective polarizing plates. The projector according to claim 1, wherein
The projector according to claim 1, wherein the reflective polarizing plate is a polarization separation prism having a polarization separation layer that reflects polarized light that should be prohibited from traveling to the projection optical system to the outside of the optical path. The projector according to claim 2,
The light incident surface of the polarization separation prism reflects the light reflected by the polarization separation layer to the outside of the optical path. The projector according to claim 1, wherein
The projector according to claim 1, wherein the reflective polarizing plate is a diffraction grating type reflective polarizing plate. The projector according to any one of claims 1 to 4,
A projector characterized in that a light guide path for guiding light reflected by the reflective polarizing plate to the display plate is provided between the reflective polarizing plate and the display plate. The projector according to claim 5, wherein
A projector characterized in that dimming means for absorbing light reflected by the reflective polarizing plate is provided between the reflective polarizing plate and the display plate. The projector according to claim 5 or 6,
A projector is provided between the reflective polarizing plate and the display plate, wherein a light amount adjusting means for adjusting a ratio at which the light reflected by the reflective polarizing plate is guided to the display plate is provided. . In the projector according to any one of claims 1 to 7,
The projector, wherein the display plate is a transmissive display device.

Images