JP2005140838A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector which is easily miniaturized and whose light utilization efficiency is not largely lowered even when it is constituted to obtain the smooth and good-quality display of a moving picture. <P>SOLUTION: The projector is equipped with: an ellipsoidal reflector 114; a light emitting tube 112; an integrator rod 120; a liquid crystal display device 400; a projection optical system 600; and a rotating wheel 30 arranged on the liquid crystal display device side of the integrator rod 120, and having a light transmission area 32 and a light reflection area 34 constituted so that a light irradiation area and a light non-irradiation area may be successively alternately scrolled synchronizing with the screen write-in frequency of the display device 400 on the display device 400. A recycle mirror 125 is arranged on the light incident surface of the integrator rod 120 and a λ/4 plate 130 and a reflection type polarizing plate 132 are arranged along a light advancing direction in this order on the liquid crystal display device side of the wheel 30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projector.

FIG. 7 is a diagram for explaining a conventional projector. FIG. 7A is a diagram showing an optical system of a conventional projector, and FIGS. 7B and 7C are diagrams for explaining the problems of such a conventional projector.
In the projector 900A, the liquid crystal display devices 400R, 400G, and 400B used as the electro-optic modulation device are hold type display devices having luminance characteristics as shown in FIG. Unlike the case of the CRT, which is an impulse type display device having the luminance characteristics as shown, there is a problem that a smooth moving image display cannot be obtained due to a so-called tailing phenomenon ( Non-patent document 1).

FIG. 8 is a diagram for explaining another conventional projector. FIG. 8A is a diagram showing an optical system of another conventional projector, and FIGS. 8B and 8C are diagrams for showing an optical shutter used in such another conventional projector. It is.
In the projector 900B, as shown in FIG. 8A, optical shutters 420R, 420G, and 420B are disposed on the light incident side of the liquid crystal display devices 400R, 400G, and 400B, and light is intermittently emitted by these optical shutters. The above problem is solved by blocking. That is, the so-called tailing phenomenon is alleviated so that a smooth and high-quality moving image display can be obtained (for example, see Patent Document 1).
"Image quality of video display on hold type display" (Technical Report of IEICE, EID99-10, pages 55-60 (1999-06)) JP 2002-148712 A (FIGS. 1 to 7)

  However, in such other conventional projectors, since an optical shutter is disposed immediately before the liquid crystal display device, there is a problem that a large optical shutter is required and it is not easy to reduce the size of the projector. In addition, in such a projector, since light is intermittently blocked by an optical shutter, there is a problem that the light use efficiency is greatly reduced.

  The present invention has been made to solve such a problem, and provides a projector having a structure that can be easily downsized even when smooth and high-quality moving image display is obtained. The first purpose. It is a second object of the present invention to provide a projector in which the light use efficiency is not significantly reduced even when a smooth and high-quality moving image display is obtained.

(1) A projector according to the present invention includes an ellipsoidal reflector, an arc tube having a light emission center near the first focal point of the elliptical reflector, and a light incident surface near the second focal point of the elliptical reflector, An integrator rod that converts light from an ellipsoidal reflector into light having a more uniform intensity distribution, an electro-optic modulator that modulates light emitted from the integrator rod in accordance with image information, and modulation by the electro-optic modulator A projection optical system for projecting the emitted light, and a rotation axis that is disposed on the electro-optic modulation device side of the integrator rod and that is parallel to the optical axis. And a light non-irradiation region are sequentially scrolled alternately in synchronization with the screen writing frequency of the electro-optic modulator. And a rotating wheel having a light reflecting region, wherein a reflecting layer having an opening for light incidence is arranged at a central portion on a light incident surface of the integrator rod, and the rotation On the electro-optic modulator side of the wheel, a λ / 4 plate and a reflective polarizing plate are arranged in this order along the light traveling direction.

For this reason, according to the projector of the present invention, the light transmission region and the light configured such that the light irradiation region and the light non-irradiation region are alternately scrolled in synchronization with the screen writing frequency of the electro-optic modulation device. Since the rotating wheel having the reflection region is provided, the light irradiation region and the light non-irradiation region are sequentially scrolled alternately in the image forming region of the electro-optic modulation device. As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.
Further, according to the projector of the present invention, since the rotating wheel having such an effect can be disposed immediately after the light exit surface of the integrator rod having a relatively small area, the size of the rotating wheel is relatively small. Therefore, the projector can be prevented from being enlarged as much as possible.
For this reason, the projector of the present invention is a projector having a structure that can be easily downsized even when smooth and high-quality moving image display is obtained, and the first object of the present invention is achieved.

According to the projector of the present invention, the light incident surface of the integrator rod is provided with a reflective layer (hereinafter referred to as “recycling mirror”) having an opening for light incidence at the center. The light reflected by the light reflecting area of the rotating wheel is returned into the integrator rod, and further reflected by the recycle mirror provided on the light incident surface side of the integrator rod and again emitted from the light emitting surface of the integrator rod. . In this case, when the emitted light is applied to the light transmission region of the rotating wheel, it is transmitted as it is. When the emitted light is applied to the light reflecting region of the rotating wheel, it is reflected and returned to the integrator rod again. Will repeat the same thing.
Therefore, according to the projector of the present invention, it is possible to reuse light and suppress a decrease in light utilization efficiency as much as possible. As a result, even when smooth and high-quality video display is obtained, The projector is such that the light use efficiency is not significantly reduced, and the second object of the present invention is also achieved.

  Furthermore, according to the projector of the present invention, the λ / 4 plate and the reflective polarizing plate are arranged in this order along the light traveling direction on the electro-optic modulation device side of the rotating wheel. When the light of one polarization component passes through the reflective polarizing plate, the light of the other polarization component is reflected by the reflective polarizing plate. Then, the reflected light is reflected by a recycle mirror provided on the light incident surface side of the integrator rod and reaches the reflective polarizing plate again. At this time, since this light has already passed through the λ / 4 plate twice, the polarization direction is rotated by 90 degrees, and passes through the reflective polarizing plate as light of one polarization component. For this reason, since all the light emitted from the integrator rod becomes light of one polarization component, the integrator rod can also function as a polarization conversion element. Therefore, it is particularly suitable for an electro-optic modulation device that controls the polarization direction, such as a liquid crystal display device.

  The above-described polarization conversion function can be obtained also when the λ / 4 plate and the reflective polarizing plate are disposed between the integrator rod and the rotating wheel, but the λ / 4 plate and the reflective polarizing plate are Since the rotary wheel is arranged on the electro-optic modulation device side, there is a problem that the λ / 4 plate and the reflective polarizing plate are easily deteriorated by heat generation. However, according to the projector of the present invention, such a problem is eliminated. .

In the projector described in (1) above, it is preferable that a light-reflecting region of the rotating wheel is formed with a reduced reflection film.
By configuring in this way, the light transmittance in the rotating wheel is improved, so that the decrease in light utilization efficiency can be minimized, the stray light level is reduced, and the contrast is improved.

(2) In the projector described in (1) above, an interval d ₁ between the integrator rod and the rotating wheel is set in a range of 0.1 mm ≦ d ₁ ≦ 0.5 mm, and the rotating wheel and the λ The distance d _{2 from the} / 4 plate is preferably set in a range of 0.1 mm ≦ d ₂ ≦ 0.5 mm.
Since the light emitted from the integrator rod is diverging light, if the distance d ₁ is too wide, the rate at which the light emitted from the integrator rod is not re-incident on the integrator rod when reflected by the rotating wheel increases. Therefore, the reuse of light is hindered and the light use efficiency is lowered. Further, if the distance d ₂ is too large, the proportion no longer be also reenters the integrator rod when the light emitted from the integrator rod is reflected by (after having passed through the rotating wheel) reflective polarizer is increased, Light reuse is hindered and light use efficiency is reduced. In any case, if the distances d ₁ and d ₂ are too wide, the light use efficiency decreases. On the other hand, if the distances d ₁ and d ₂ are too narrow, the rotating wheel cannot freely rotate between the integrator rod and the λ / 4 plate, and it becomes difficult to perform smooth light quantity control. For this reason, it is preferable to set the distances d ₁ and d ₂ in the above range. From these viewpoints, the distance d ₁ is more preferably set in the range of 0.2 mm ≦ d ₁ ≦ 0.3 mm, and the distance d ₂ is in the range of 0.2 mm ≦ d ₂ ≦ 0.3 mm. More preferably, it is set to.

(3) In the projector according to (1) or (2), the λ / 4 plate is preferably made of an inorganic material.
The light immediately after being emitted from the integrator rod has extremely high light intensity per unit area. For this reason, if light is absorbed even a little by the λ / 4 plate, a large amount of heat is generated, and the temperature of the λ / 4 plate increases. For this reason, it is preferable to use what consists of an inorganic material with high heat resistance as (lambda) / 4 board. Examples of the inorganic material having high heat resistance include mica and quartz.

(4) In the projector according to any one of (1) to (3), the reflective polarizing plate is preferably made of an inorganic material.
As described above, the light immediately after being emitted from the integrator rod has a very strong light intensity per unit area. For this reason, if light is absorbed even a little by the reflective polarizing plate, a large amount of heat is generated, and the temperature of the reflective polarizing plate becomes high. For this reason, it is preferable to use what consists of an inorganic material with high heat resistance as a reflection type polarizing plate. As such a material, a wire-grid reflective inorganic polarizing plate in which a metal film is formed in a fine stripe shape on a glass substrate can be exemplified.

(5) In the projector according to any one of (1) to (4), a λ / 2 plate may be disposed on the electro-optic modulation device side of the reflective polarizing plate.
With this configuration, the polarization direction of the light emitted from the reflective polarizing plate can be rotated by 90 °, and an optical system that does not match the polarization direction when a λ / 2 plate is not used is provided later. It can be used as an optical system.

(6) In the projector according to (5), the λ / 2 plate is preferably made of an inorganic material.
The light immediately after being emitted from the integrator rod has extremely high light intensity per unit area. For this reason, if light is absorbed even a little by the λ / 2 plate, a large amount of heat is generated, and the temperature of the λ / 2 plate increases. For this reason, it is preferable to use a λ / 2 plate made of an inorganic material having high heat resistance. Examples of the inorganic material having high heat resistance include mica and quartz.

(7) In the projector according to any one of (1) to (6), the light emitting tube reflects light emitted from the light emitting tube toward the illuminated region toward the ellipsoidal reflector. It is preferable that a reflecting means is provided.
With this configuration, the light emitted from the arc tube toward the illuminated area is reflected toward the ellipsoidal reflector, so the elliptical surface is sized to cover the illuminated area side end of the arc tube. It is not necessary to set the size of the reflector, and the ellipsoidal reflector can be downsized. As a result, the projector can be downsized.
Further, since the ellipsoidal reflector can be reduced in size, the focusing angle and beam spot of the beam focused from the ellipsoidal reflector toward the second focal point of the ellipsoidal reflector can be reduced, and the size of the optical shutter can be reduced. Further, the size of the integrator rod, the size of the rotating wheel, and the like can be further reduced, and the projector can be further miniaturized.

  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 for explaining a projector according to a first embodiment of the invention. 1 (a) is a plan view, FIG. 1 (b) is a side view, FIG. 1 (c) is a view for explaining the rotating wheel of FIGS. 1 (a) and (b), FIG. 1D is a diagram showing an illumination state on a liquid crystal display device as an electro-optic modulation device that is an illuminated area.

  As shown in FIGS. 1A and 1B, the projector 1000A according to the first embodiment emits an illumination light beam, and emits light from the illumination optical system 100 according to image information. It includes a liquid crystal display device 400 as an electro-optic modulation device that modulates, and a projection optical system 600 that projects light modulated by the liquid crystal display device 400 onto a projection surface such as a screen SCR.

  The illumination optical system 100 includes a light source device 110 having an ellipsoidal reflector 114, a light-emitting tube 112 composed of a high-pressure mercury lamp and the like, and an auxiliary mirror 116 as a reflecting means, and light emitted from the light source device 110 is emitted from the liquid crystal display device 400. An integrator rod 120 for uniformly irradiating the image display area (illuminated area), and a relay optical system 140 for guiding the light emitted from the integrator rod 120 onto the image display area (illuminated area) of the liquid crystal display device 400. And have.

  In the projector 1000A according to the first embodiment, as shown in FIGS. 1A and 1B, the light incident surface of the integrator rod 120 is disposed in the vicinity of the second focal position of the ellipsoidal reflector 114. . A rotating wheel 30 is disposed on the liquid crystal display device side of the integrator rod 120. The rotating wheel 30 has a rotation axis parallel to the optical axis as shown in FIG. 1 (b), and, as shown in FIG. 1 (c), the light irradiation region on the liquid crystal display device 400 by the rotation. And a light non-irradiation region having a light transmission region 32 and a light reflection region 34 as a light non-transmission region configured to be alternately scrolled in synchronization with the screen writing frequency of the liquid crystal display device 400. Yes.

Therefore, according to the projector 1000A according to the first embodiment, as shown in FIG. 1D, in the image forming region of the liquid crystal display device 400, the light irradiation region and the light non-irradiation region are the screen of the liquid crystal display device 400. Scrolls sequentially along the writing direction. As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.
Further, according to the projector 1000A according to the first embodiment, the rotating wheel 30 that exhibits such an effect can be disposed immediately after the light exit surface of the integrator rod 120 having a relatively small area. The size of the projector can be made relatively small, and the size of the projector can be suppressed as much as possible.
Therefore, the projector 1000A according to the first embodiment is a projector having a structure that can be easily downsized even when smooth and high-quality moving image display is obtained.

  FIG. 2 is a diagram for explaining a main part of the projector according to the first embodiment. FIG. 2A is a diagram illustrating a main part of the projector according to the first embodiment, and FIG. 2B is a diagram illustrating a main part of the projector according to the modification. FIG. 3 is a diagram for explaining a polarization conversion function in the projector 1000A according to the first embodiment. FIG. 3A is a diagram for explaining the polarization conversion function in the projector according to the first embodiment, and FIG. 3B is a diagram for explaining the polarization conversion function in the projector according to the comparative example.

In the projector 1000A according to the first embodiment, as shown in FIGS. 1A, 1B, and 2, the light incident surface of the integrator rod 120 has an opening for light incidence at the center. A reflective layer (recycle mirror) 125 is disposed. For this reason, as shown in “A” of FIG. 3A, the light reflected by the light reflecting region 34 of the rotating wheel 30 is returned into the integrator rod 120 and further on the light incident surface side of the integrator rod 120. The light is reflected by the provided recycle mirror 125 and emitted from the light exit surface of the integrator rod 120 again. In this case, when the emitted light is applied to the light transmission region 32 of the rotating wheel 30, it is transmitted as it is. When the emitted light is applied to the light reflecting region 34 of the rotating wheel 30, it is reflected again. It is returned to the integrator rod 120 and the same thing is repeated again.
For this reason, according to the projector 1000A according to the first embodiment, light can be reused, and a decrease in light utilization efficiency can be suppressed as much as possible. As a result, a smooth and high-quality video display can be obtained. Sometimes, the projector does not have a significant decrease in light utilization efficiency.

  In the projector 1000A according to the first embodiment, as shown in FIG. 1A, FIG. 1B, FIG. 2 and FIG. The λ / 4 plate 130 and the reflective polarizing plate 132 are arranged along this order. For this reason, when light of one polarization component (P-polarized light) passes through the reflective polarizing plate 132 as indicated by “B1” in FIG. 3A, as indicated by “B2” in FIG. The other polarization component light (S-polarized light) is reflected by the reflective polarizing plate 132. The reflected light is reflected by the recycle mirror 125 provided on the light incident surface side of the integrator rod 120 and reaches the reflective polarizing plate 132 again. At this time, since this light has already passed through the λ / 4 plate 130 twice, the polarization direction is rotated by 90 degrees, and passes through the reflective polarizing plate 132 as light of one polarization component (P-polarized light). For this reason, since all the light emitted from the integrator rod 120 becomes light of one polarization component (P-polarized light), the integrator rod 120 can also function as a polarization conversion element. Therefore, it is particularly suitable for an electro-optic modulation device that controls the polarization direction, such as a liquid crystal display device.

  In addition, as shown in FIG. 3B, the polarization as described above also occurs when the λ / 4 plate 130 and the reflective polarizing plate 132 are disposed between the integrator rod 120 and the rotating wheel 30. A conversion function is obtained. However, in this case, there is a drawback that the λ / 4 plate 130 and the reflective polarizing plate 132 are easily deteriorated. That is, in this case, when the light emitted from the integrator rod 120 is reflected by the light reflection region 34 of the rotating wheel 30, as shown in “A1” in FIG. The emitted light first passes through the λ / 4 plate 130 and the reflective polarizing plate 132, and then is reflected by the light reflecting region 34 of the rotating wheel 30, and then passes through the reflective polarizing plate 132 and the λ / 4 plate 130 again. pass. Then, the light reenters the integrator rod 120. Then, the light is reflected by the recycle mirror 125, reflected by the reflective polarizing plate 132, and re-enters the integrator rod 120 as shown by "A2" in FIG. Then, this light is reflected by the recycle mirror 125 to become light as indicated by “A1” in FIG. 3A, and this operation is repeated. Therefore, by repeatedly passing the λ / 4 plate 130 and the reflective polarizing plate 132 over and over again, the λ / 4 plate 130 and the reflective polarizing plate 132 become high temperature due to heat generated by the light absorption. It becomes easy to deteriorate.

  In the projector 1000A according to the first embodiment, the solid-type integrator rod 120 is used as the integrator rod. However, as shown in FIG. 2B, a hollow-type integrator rod 120B can also be used.

  In the projector 1000 </ b> A according to the first embodiment, a light reflection region 32 is formed with a antireflection film. For this reason, the light transmittance is improved, and a decrease in light use efficiency due to the use of the rotating wheel can be minimized, and the stray light level is reduced and the contrast is improved.

In the projector 1000A according to Embodiment 1, with reference to FIG. 2 (a), distance _{d 1} between the integrator rod 120 and the rotary wheel 30 is set to 0.25 mm, a rotating wheel 30 lambda / 4 plate 130 distance _{d 2} between is set to 0.25 mm.
For this reason, when the light emitted from the integrator rod 120 is reflected by the rotating wheel 30, most of the light is incident on the integrator rod 120 again. Further, when the light emitted from the integrator rod 120 is reflected by the reflective polarizing plate 132 (after passing through the rotating wheel 30), it is again incident on the integrator rod 120. For this reason, the reuse of light is ensured and the light utilization efficiency does not decrease.

  In projector 1000A according to Embodiment 1, λ / 4 plate 130 is made of mica having high heat resistance. For this reason, even if the λ / 4 plate 130 is heated by strong light from the integrator rod 120, it does not deteriorate. As the λ / 4 plate, in addition to those made of mica, those made of quartz can be preferably used.

  In projector 1000A according to Embodiment 1, reflective polarizing plate 132 is made of a reflective inorganic polarizing plate with high heat resistance. For this reason, even if the reflective polarizing plate 132 becomes high temperature due to strong light from the integrator rod 120, it does not deteriorate. As the reflective inorganic polarizing plate, a wire grid type reflective inorganic polarizing plate (for example, manufactured by MOSTEK) having a metal film formed in a fine stripe shape on a glass substrate can be preferably used.

In the projector 1000A according to the first embodiment, the arc tube 112 is provided with an auxiliary mirror 116 as a reflection unit that reflects light emitted from the arc tube 112 toward the illuminated area toward the ellipsoidal reflector 114. .
For this reason, since the light emitted from the arc tube 112 toward the illuminated area is reflected toward the elliptical reflector 114, the elliptical reflector 114 is sized so as to cover the illuminated area side end of the arc tube 112. Therefore, the ellipsoidal reflector 114 can be reduced in size, and as a result, the projector can be reduced in size.
Further, since the size of the ellipsoidal reflector 114 can be reduced, the focusing angle and beam spot of the beam focused from the ellipsoidal reflector 114 toward the second focal point of the ellipsoidal reflector 114 can be reduced. The size of 120, the size of the rotating wheel 30, and the like can be further reduced, and the projector can be further miniaturized.

[Embodiment 2]
FIG. 4 is a diagram showing an optical system of the projector according to the second embodiment of the invention. As shown in FIG. 4, the projector 1000B according to the second embodiment includes three liquid crystal display devices 400R, 400G, and 400B, and an optical system that equidistants from the rotating wheel 30 to the liquid crystal display devices 400R, 400G, and 400B. The system is adopted. For this reason, in the projector 1000B according to the second embodiment, an equivalent scroll system is configured for each color, and full color display with good color reproducibility can be realized.

In the projector 1000B according to the second embodiment, light irradiation is performed in synchronization with the screen writing frequency of the liquid crystal display devices (the liquid crystal display devices 400R, 400G, and 400B) as in the case of the projector 1000A according to the first embodiment. The liquid crystal display device (liquid crystal display devices 400R, 400G, and 400B) is provided with the rotating wheel 30 having the light transmission region and the light reflection region configured such that the region and the light non-irradiation region are sequentially scrolled alternately. In each of the image forming regions, the light irradiation region and the light non-irradiation region are sequentially scrolled along the screen writing direction of the liquid crystal display devices (liquid crystal display devices 400R, 400G, 400B). As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.
Further, according to the projector 1000B according to the second embodiment, the rotating wheel 30 that exhibits such an effect is disposed immediately after the light emission surface (light emission side) of the integrator rod 120 having a relatively small area. As in the case of the projector 1000A according to the first embodiment, the size of the rotating wheel 30 can be made relatively small, and the size of the projector can be suppressed as much as possible.
Therefore, the projector 1000B according to the second embodiment is a projector having a structure that can be easily downsized even when smooth and high-quality moving image display is obtained.

In the projector 1000B according to the second embodiment, the recycle mirror 125 is disposed on the light incident surface of the integrator rod 120, similarly to the projector 1000A according to the first embodiment. For this reason, the light reflected by the light reflecting region 34 of the rotating wheel 30 is returned into the integrator rod 120 and further reflected by the recycle mirror 125 provided on the light incident surface side of the integrator rod 120 to It is emitted again from the light exit surface. In this case, when the emitted light is applied to the light transmission region 32 of the rotating wheel 30, it is transmitted as it is. When the emitted light is applied to the light reflecting region 34 of the rotating wheel 30, it is reflected again. It is returned to the integrator rod 120 and the same thing is repeated again.
For this reason, according to the projector 1000B according to the second embodiment, light can be reused, and a decrease in light utilization efficiency can be suppressed as much as possible. As a result, a smooth and high-quality moving image display can be obtained. Sometimes, the projector does not have a significant decrease in light utilization efficiency.

  Further, in the projector 1000B according to the second embodiment, similarly to the projector 1000A according to the first embodiment, the λ / 4 plate 130 and the reflective polarizing plate are disposed on the liquid crystal display device side of the rotating wheel 30 along the light traveling direction. 132 are arranged in this order. For this reason, when the light of one polarization component (P-polarized light) passes through the reflective polarizing plate 132, the light of the other polarization component (S-polarized light) is reflected by the reflective polarizing plate 132. The reflected light is reflected by the recycle mirror 125 provided on the light incident surface side of the integrator rod 120 and reaches the reflective polarizing plate 132 again. At this time, since this light has already passed through the λ / 4 plate 130 twice, the polarization direction is rotated by 90 degrees, and passes through the reflective polarizing plate 132 as light of one polarization component (P-polarized light). For this reason, since all the light emitted from the integrator rod 120 becomes light of one polarization component (P-polarized light), the integrator rod 120 can also function as a polarization conversion element. Therefore, it is particularly suitable for an electro-optic modulation device that controls the polarization direction, such as a liquid crystal display device.

[Embodiment 3]
FIG. 5 is a diagram for explaining the projector according to the third embodiment of the invention. FIG. 5A is a plan view, FIG. 5B is a side view, and FIG. 5C is a diagram showing a main part of the projector according to the third embodiment. FIG. 6 is a diagram for explaining a polarization conversion function in the projector according to the third embodiment.

  As shown in FIGS. 5A and 5B, the projector 1000C according to the third embodiment basically has the same configuration as the projector 1000A according to the first embodiment. For this reason, the projector 1000C according to the third embodiment has the same effect as the projector 1000A according to the first embodiment.

However, in the projector 1000C according to the third embodiment, as shown in FIGS. 5 and 6, the λ / 2 plate 134 is arranged on the liquid crystal display device side of the reflective polarizing plate 132 in the projector 1000A according to the first embodiment. Yes. Therefore, in the projector 1000A according to the first embodiment, as shown by “B1” and “B2” in FIG. 3A, light of one polarization component (P-polarized light) is emitted from the reflective polarizing plate 132. In contrast, in the projector 1000C according to the third embodiment, as shown by “B1” and “B2” in FIG. 6, the light that has passed through the reflective polarizing plate 132 passes through the λ / 2 plate 134. Thus, the light of the other polarization component (S-polarized light) is emitted from the λ / 2 plate 134. That is, the polarization direction of the light emitted from the reflective polarizing plate 132 can be rotated by 90 °, and an optical system that does not match the polarization direction when the λ / 2 plate 134 is not used is used as the subsequent optical system. Can be used.
For example, in the projector 1000A according to the first embodiment, when the polarization direction of the light incident on the liquid crystal display device 400 is not suitable, the optical system of the projector 1000C according to the third embodiment is adopted, thereby the liquid crystal display device 400. The polarization direction of the light incident on the light beam is adapted.
In the case where a color separation optical system is used as the subsequent optical system, such as the projector 1000B according to the second embodiment, in the case of the projector 1000B according to the second embodiment, the polarization direction of light incident on the dichroic mirror is dichroic. When the reflection characteristic of the mirror is not suitable, by adopting the optical system of the projector 1000C according to the third embodiment, the polarization direction of the light incident on the dichroic mirror is adapted to the reflection characteristic of the dichroic mirror. .

  In the projector 1000C according to the third embodiment, the λ / 2 plate 134 is made of mica having high heat resistance. For this reason, even if the λ / 2 plate 134 is heated by strong light from the integrator rod 120, it does not deteriorate. As the λ / 2 plate, in addition to those made of mica, those made of quartz can be preferably used.

  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) Although the projectors 1000A to 1000C in the above embodiments are transmissive projectors, the present invention can also be applied to a reflective projector. Here, “transmission type” means that an electro-optic modulation device as a light modulation means, such as a transmission type liquid crystal display device, transmits light, and “reflection type” means This means that an electro-optic modulation device as a light modulation means, such as a reflective liquid crystal display 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.

(2) The projectors 1000 </ b> A to 1000 </ b> C of the above embodiments use a liquid crystal display device as an electro-optic modulation device, but 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.

FIG. 3 is a diagram for explaining the projector according to the first embodiment. FIG. 3 is a diagram for illustrating a main part of the projector according to the first embodiment. FIG. 3 is a diagram for explaining a polarization conversion function in the projector according to the first embodiment. FIG. 6 is a diagram for explaining a projector according to a second embodiment. FIG. 6 is a diagram for explaining a projector according to a third embodiment. FIG. 10 is a diagram for explaining a polarization conversion function in a projector according to a third embodiment. The figure shown in order to demonstrate the conventional projector. The figure shown in order to demonstrate another conventional projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Motor, 30 ... Rotating wheel, 32 ... Light transmission area, 34 ... Light reflection area, 100, 100C ... Illumination optical system, 110 ... Light source device, 112 ... Light emitting tube, 114 ... Ellipsoidal reflector, 120, 120B ... Integrator Rod, 122 ... Optical glass, 124 ... Mirror, 125 ... Recycle mirror, 130 ... λ / 4 plate, 132 ... Reflective polarizing plate, 134 ... λ / 2 plate, 140 ... Relay optical system, 400, 400R, 400G, 400B Liquid crystal display device 500 Cross dichroic prism 600 Projection optical system 900A, 900B, 1000A, 1000B, 1000C Projector

Claims (7)

An ellipsoidal reflector;
An arc tube having an emission center near the first focal point of the ellipsoidal reflector;
An integrator rod having a light incident surface in the vicinity of the second focal point of the elliptical reflector, and converting light from the elliptical reflector into light having a more uniform intensity distribution;
An electro-optic modulator that modulates the light emitted from the integrator rod in accordance with image information;
A projection optical system that projects light modulated by the electro-optic modulation device;
The integrator rod is disposed on the electro-optic modulation device side and has a rotation axis parallel to the optical axis. By the rotation, the light irradiation region and the light non-irradiation region are modulated on the electro-optic modulation device. A projector comprising a rotating wheel having a light transmission region and a light reflection region configured to be sequentially and alternately scrolled in synchronization with a screen writing frequency of the device,
On the light incident surface of the integrator rod, a reflection layer having an opening for light incidence is arranged at the center,
A projector, wherein a λ / 4 plate and a reflective polarizing plate are arranged in this order along the light traveling direction on the electro-optic modulator side of the rotating wheel. The projector according to claim 1, wherein
An interval d ₁ between the integrator rod and the rotating wheel is set in a range of 0.1 mm ≦ d ₁ ≦ 0.5 mm, and an interval d ₂ between the rotating wheel and the λ / 4 plate is 0.1 mm ≦ A projector characterized by being set in a range of d ₂ ≦ 0.5 mm. The projector according to claim 1 or 2,
The projector, wherein the λ / 4 plate is made of an inorganic material. The projector according to any one of claims 1 to 3,
The projector according to claim 1, wherein the reflective polarizing plate is made of an inorganic material. The projector according to any one of claims 1 to 4,
A projector having a λ / 2 plate disposed on the electro-optic modulator side of the reflective polarizing plate. The projector according to claim 5, wherein
The λ / 2 plate is made of an inorganic material. In the projector according to any one of claims 1 to 6,
The projector according to claim 1, wherein the arc tube is provided with reflecting means for reflecting light emitted from the arc tube toward the illuminated area toward the ellipsoidal reflector.

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