JP2006308787A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector that improves uneven illuminance. <P>SOLUTION: The illuminating optical system 41 of the projector includes: a light source 416; a first lens array 412 having a plurality of first small lenses for splitting luminous flux from the light source 416 into a plurality of partial luminous fluxes; a second lens array 413 having a plurality of second small lenses corresponding to the plurality of first small lenses; a superposing lens 415 for superposing the plurality of partial luminous fluxes onto the image forming area of a light modulating device together with the second lens array 413; and a diaphragm mechanism 45 for intercepting the illuminating luminous flux from the first lens array 412. The diaphragm mechanism 45 has light shielding members 451 and 452 that turn to adjust reduction quantity of light of the illuminating luminous flux. Each of the light shielding members 451 and 452 has openings, through each of which part of light of each partial luminous flux is passed while the light shielding members 451 and 452 are turned until the light of the illuminating luminous flux is reduced to the smallest quantity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination optical system having a light source, an optical image forming system having a light modulation device that modulates a light beam emitted from the illumination optical system in accordance with image information to form an optical image, and formed optics. The present invention relates to a projector including a projection optical system for enlarging and projecting an image.

  2. Description of the Related Art Conventionally, projectors are frequently used for presentations at conferences, academic conferences, exhibitions, etc., and home theaters. As such a projector, an illumination optical system having a light source and an optical image forming system having a light modulation device that modulates a light beam emitted from the illumination optical system according to image information to form an optical image are formed. A configuration including a projection optical system for enlarging and projecting an optical image is known. Further, as such an illumination optical system, according to a first lens array having a plurality of first small lenses for dividing a light beam emitted from a light source into partial light beams, and a plurality of first small lenses of the first lens array. There is a known configuration including a plurality of second small lenses and a second lens array that superimposes the divided partial light beams on an image forming region of a light modulation device.

  Such a first lens array and a second lens array are for uniformizing the in-plane illuminance of the light beam emitted from the light source and irradiating the image forming area of the light modulation device. Here, when a light source device including a discharge light source lamp and a reflector that condenses the light beam emitted from the discharge light source lamp and emits it to the illuminated area is used as the light source of the projector, The luminous flux emitted from the light source device has a high illumination intensity near the optical axis, and the illumination intensity tends to decrease toward the outer edge. When such a light beam is directly applied to the image forming area of the light modulation device, the illuminance at the center of the image forming area becomes high, and an optical image with large illuminance unevenness is formed in the image plane. For this reason, the first lens array and the second lens array are employed in the illumination optical system, and the light flux is transmitted through the first lens array and the second lens array so that the in-plane illuminance in the illumination area is uniformed. It is possible to irradiate the image forming area of the light modulation device, thereby forming an optical image in which illuminance unevenness is suppressed.

By the way, in a projector, the light quantity of the light beam emitted from the light source and entering the light modulation device may be adjusted in order to improve the contrast of the projected image. However, when a discharge light source such as a high-pressure mercury lamp is used as the light source, even if the light emission amount of the light source is simply reduced, the light emission amount of 100% can be reduced only to about 70%. There was a problem that the amount of light could not be reduced sufficiently.
In order to solve such a problem, a projector including a light shielding unit that partially shields a light beam emitted from a light source is known (see, for example, Patent Document 1).

  The projector described in Patent Document 1 includes a lighting device including a light source, a light source driving unit that adjusts the amount of light emitted from the light source, and a light blocking unit (optical diaphragm) that adjusts the amount of light flux extracted from the light source. Among these, the light shielding unit has a function of partially shielding the light beam from the light source and reducing the light amount of the light beam irradiated to the light modulation device located at the subsequent stage of the light shielding unit. Thereby, the light quantity of the light beam taken out from the light source lamp can be adjusted over a wide range.

JP 2004-264819 A

However, when the light beam emitted from the light source device and incident on the second lens array via the first lens array is dimmed by the light shielding means of the projector described in Patent Document 1, the light beam having a uniform in-plane illuminance in the illumination area Therefore, it is difficult to properly illuminate the image forming area of the light modulation device. For this reason, there exists a problem that the illumination intensity ratio of a projection image deteriorates compared with the case where it is not dimmed.
More specifically, an optical stop that rotates the light shielding member to partially shield the light beam from the light source device can adjust the attenuation rate finely because the movable range of the light shielding member is wide. As the light rate is increased, in other words, the partial light beams divided by the first lens array are sequentially shielded from the outside by the light shielding member, and the number of partial light beams incident on the second lens array is decreased and dimmed. Only the partial light beam near the center of the optical axis of the illumination light beam reaches the second lens array. For this reason, since the partial light beam does not enter the second small lens in the vicinity of the outer edge among the plurality of second small lenses constituting the second lens array, the portion to be superimposed is compared with the case where the light is not dimmed. The number of light beams decreases, and the effect of equalizing the in-plane illuminance by dividing the light beam from the light source device into a plurality of partial light beams and superimposing the divided partial light beams on the image forming area of the light modulation device is reduced. Therefore, there is a problem that the in-plane illuminance of the light beam applied to the image forming area of the light modulation device is deteriorated, and as a result, uneven illuminance of the projected image occurs. Therefore, when an image is formed using such a light beam, there is a problem that image deterioration such as color unevenness is caused.

  An object of the present invention is to provide a projector that can improve illuminance unevenness even when the amount of light extracted from a light source is adjusted.

  In order to achieve the above object, a projector according to the present invention includes an illumination optical system that emits an illumination light beam, and light that forms an optical image by modulating the illumination light beam emitted from the illumination optical system according to image information. A projector comprising an optical image forming system having a modulation device and a projection optical system for enlarging and projecting the formed optical image, wherein the illumination optical system includes a light source and a plurality of illumination light beams emitted from the light source. A first lens array having a plurality of first small lenses that are divided into a plurality of partial light beams, and a second lens array having a plurality of second small lenses corresponding to the plurality of partial light beams divided by the first lens array; A superposition lens that superimposes the plurality of partial light beams on the image forming area of the light modulation device together with the second lens array, and is disposed between the first lens array and the second lens array. A diaphragm mechanism that partially shields the illumination light beam emitted from the first lens array, and the diaphragm mechanism includes a light shielding member that adjusts the original material of the illumination light beam by rotating, The member includes an opening for transmitting a part of light for each of the partial light beams in a state where the light shielding member is rotated until the illumination light beam is most dimmed.

According to the present invention, the projector includes an aperture mechanism having a light blocking member that partially blocks the partial light beam emitted from the light source and divided by the first lens array in order to adjust the amount of light that illuminates the light modulation device. The light shielding member is provided with an opening through which a part of light is transmitted for each partial light beam in a state where the light shielding member is rotated until the illumination light beam is most dimmed.
According to this, when the light shielding member is rotated and the light shielding member is interposed on the optical path of the illumination light beam emitted from the first lens array, the first lens is passed through the opening formed in the light shielding member. For each partial light beam emitted from the array, a part of the partial light beam can be transmitted and incident on the second lens array. This prevents the number of partial light beams to be superimposed on the image forming area of the light modulation device from being reduced by the second lens array and the superimposing lens as compared with the case where a light shielding member having no opening is used. In addition, the illumination light flux that illuminates the image forming area of the light modulation device can be reduced. Therefore, even when dimmed, the effect of equalizing the in-plane illuminance of the illumination light beam that illuminates the image forming region of the light modulation device is maintained by dividing the light beam from the light source into a plurality of partial light beams and superimposing them. Therefore, it is possible to suppress the occurrence of illuminance unevenness in the formed image.
Further, when a light source that forms a light source image on the second lens array is used as the light source when the light shielding member does not block the optical path, the light path of the light beam is blocked by the light shielding member, that is, the light shielding member Even when the light beam emitted from one lens array is shielded most, a light source image corresponding to the opening is formed on each second small lens of the second lens array through the opening formed in the light shielding member. be able to.

In the present invention, the light source includes an arc tube having a light emitting unit on a central axis of the illumination light beam, and a reflecting mirror that reflects light emitted from the arc tube in a predetermined direction. Preferably, each of the light shielding members includes a pair of the light shielding members each having the opening, and the pair of light shielding members are disposed at substantially symmetrical positions around the central axis of the illumination light beam emitted from the first lens array. .
According to the present invention, the illumination light beam emitted from the first lens array by the pair of light shielding members is light-shielded and attenuated symmetrically with respect to the central axis, thereby illuminating the image forming area of the light modulation device. In addition to achieving fine adjustment of the light intensity without impairing the uniformity of the in-plane illuminance of the illumination light beam to be performed, the aperture mechanism can be miniaturized, so that the degree of freedom in designing the projector can be improved.

That is, the light beam emitted from the light source that reflects the light emitted from the arc tube having the light emitting unit on the central axis of the illumination light beam in a predetermined direction by the reflecting mirror is near the central axis of the illumination light beam as described above. The illumination intensity is high, and the illumination intensity tends to decrease as it goes from the central axis of the illumination light beam to the outer edge. Here, when the light beam emitted from the first lens array is blocked by one light blocking member, the outer edge on the side where the light blocking member is arranged and the vicinity of the central axis as the light blocking member blocks the optical path of the light beam. Since the light beam is shielded in the order of the outer edge on the side opposite to the side where the light shielding member is disposed, the light attenuation rate suddenly increases when the light beam near the central axis is shielded, and light attenuation with little fluctuation can be performed. difficult.
In addition, when the illumination light beam emitted from the light source that emits the illumination light beam with non-uniform in-plane illuminance is divided into a plurality of partial light beams by the first lens array, the partial light beam that is symmetrical about the central axis of the illumination light beam is obtained. The distribution of the in-plane illuminance of each light source image to be formed is a symmetric distribution with respect to the central axis of the illumination light beam. Here, when the partial light beam emitted from the first lens array is shielded by one light shielding member, the outer edge on the side where the light shielding member is arranged as the light shielding member rotates to increase the light reduction amount of the illumination light flux. Since the illumination light beam is shielded in the order of the vicinity of the central axis and the outer edge on the side opposite to the side where the light shielding member is disposed, the light beam is asymmetrically shielded with respect to the central axis of the illumination light beam. For this reason, even if a plurality of partial light beams that are shielded asymmetrically with respect to the central axis of the illumination light beam are superimposed on the image forming region of the light modulation device, it is difficult to keep the in-plane illuminance of the illumination light beam uniform.

  On the other hand, when the light is shielded by a pair of light shielding members arranged at substantially symmetrical positions around the central axis of the illumination light beam, a range that is symmetrical from the illumination light beam near the outer edge with low intensity to the central axis of the illumination light beam As a result, the illumination light beam near the center axis is shielded, so that the fluctuation of the light attenuation rate with respect to the rotation amount of the light shielding member can be suppressed, and the illuminance distribution with respect to the center axis of the illumination light beam can be made uniform. it can. Accordingly, the light attenuation rate can be finely set, and the in-plane illuminance of the illumination light beam can be kept uniform.

  Further, when the light beam is shielded by one light shielding member, the light shielding member needs to have at least the same outer dimensions as the illuminated region of the second lens array. However, by providing a pair of light shielding members, The moving range of the light shielding member can be reduced. Furthermore, when the light path of the illumination light beam is blocked by one light shielding member and when the light path is opened, the amount of movement of the light shielding member becomes large. The dimension and movement amount of the member can be reduced. Here, since the distance between the first lens array and the second lens array is determined by these optical characteristics, the movement amount and size of each light shielding member can be reduced. The range of selection of characteristics can be expanded. Therefore, the degree of freedom in designing the projector can be improved.

In the present invention, the illumination optical system includes a polarization conversion element that converts a plurality of partial light beams divided by the first lens array into substantially one type of linearly polarized light, and the polarization conversion element includes a polarization separation layer, A reflection layer, and a retardation plate disposed corresponding to one of the polarization separation layer and the reflection layer, wherein the polarization separation layer and the reflection layer have a longitudinal direction in a direction matching each other. And arranged in a plurality of rows alternately in a direction substantially orthogonal to the longitudinal direction, and the rotation axis of the light shielding member is disposed along a direction substantially orthogonal to the longitudinal direction of the polarization separation layer. preferable.
According to the present invention, the light shielding member having the rotation shaft arranged along the direction orthogonal to the longitudinal direction of the polarization separation layer and the reflection layer is orthogonal to the longitudinal direction of the plurality of partial light beams incident on the deflection separation layer. The light can be shielded in order from the direction, and the rotation amount of the light shielding member can be easily adjusted with respect to a desired light reduction amount of the illumination light beam.

Here, when the light shielding member has a rotation axis along the longitudinal direction of the polarization separation layer and the reflection layer, the light shielding member is rotated while shielding a plurality of partial light beams incident on the polarization separation layer. When the partial light beam incident on the polarization separation layer is shielded and rotated until the partial light beam incident on the next polarization separation layer is shielded (the portion corresponding to the reflection layer is rotated), the light is shielded. The ratio between the amount of rotation of the member and the amount of reduced light of the illumination light flux varies.
On the other hand, the light shielding member has a rotation axis along a direction orthogonal to the longitudinal direction of the polarization separation layer and the reflection layer, and a plurality of partial light beams incident on the polarization separation layer are orthogonal to the longitudinal direction of the polarization separation layer. In the case where the light is shielded in order, the variation in the ratio between the rotation amount of the light shielding member and the reduced amount of the illumination light beam can be reduced, so that the reduced light amount of the illumination light beam can be easily adjusted.

In the present invention, the plurality of second small lenses of the second lens array are arranged along the longitudinal direction of the polarization separation layer, and the opening is formed in a slit shape according to the arrangement of the second small lenses. It is preferable that
According to the present invention, the opening of the light shielding member is formed in a slit shape according to the arrangement of the second small lenses of the second lens array arranged along the longitudinal direction of the polarization separation layer. That is, the opening of the light shielding member is formed in a slit shape along the longitudinal direction of the polarization separation layer of the polarization conversion element. For this reason, even if the light shielding member rotates so as to increase the attenuation rate of the illumination light beam that illuminates the image forming area of the light modulation device, that is, to block the optical path of the illumination light beam, the first lens array Each of the emitted partial light beams partially passes through the opening of the light shielding member formed along the longitudinal direction of the polarization separation layer and enters each second small lens of the second lens array. According to this, the illumination light beam incident on the image forming area of the light modulation device can be reduced, and the number of the plurality of partial light beams is not reduced. It can be illuminated with an illumination beam. Therefore, it is possible to suppress unevenness in illuminance of the image projected by the projector.
Further, since the opening is formed in a slit shape, the improvement in the illuminance ratio as described above can be realized with a simple opening. Accordingly, the light shielding member can be easily manufactured.

In the present invention, it is preferable that the slit-shaped opening is formed along a direction substantially orthogonal to the axial direction of the rotating shaft, and the side opposite to the rotating shaft is cut away.
According to the present invention, when the partial light beam emitted from the first lens array is shielded by rotating the light shielding member, it is possible to perform the light attenuation with the variation of the light attenuation rate being further suppressed, and the plurality of portions. It is possible to irradiate the image forming area of the light modulation device with an illumination light beam having a uniform illuminance without reducing the number of light beams.
That is, the slit-shaped opening of the light shielding member is formed along a direction orthogonal to the rotation axis of the light shielding member, and the opposite side of the rotation shaft is formed by cutting away, The light shielding member is formed in a substantially comb shape. According to this, even when the optical path of the illumination light beam is gradually blocked by the light shielding member, it is possible to prevent the partial light beam having a high intensity near the central axis of the illumination light beam from being suddenly shielded at the beginning of dimming. . Thereby, the light attenuation rate can be made uniform. Therefore, it is possible to perform dimming while suppressing a rapid variation in the illumination intensity of the illumination light beam that illuminates the image forming area of the light modulation device.

  In addition, since the opening of the light shielding member is formed in a direction substantially orthogonal to the rotation axis, even when the light shielding member is rotated so as to gradually block the optical path of the illumination light beam, Each of the plurality of partial light beams incident on the polarization separation layer of the polarization conversion element is partially transmitted and superimposed on the image forming area of the light modulation device without reducing the number of the plurality of partial light beams, and has a uniform in-plane illuminance. The image forming area can be irradiated with the illumination light beam.

In the present invention, the width of the slit-shaped opening is preferably formed so as to become narrower toward the center of the light shielding member in the longitudinal direction of the polarization separation layer.
According to the present invention, the width of the slit-shaped opening is formed so as to become narrower toward the center of the light shielding member in the longitudinal direction of the polarization separation layer of the polarization conversion element. , The illumination intensity of the incident light beam on the image forming area of the light modulation device can be further reduced, and the contrast of the optical image projected by the projector can be improved. In addition, by adjusting the size of the opening, each of the second small lenses of the second lens array can be reliably irradiated with the reduced partial light beam. Therefore, the number of partial light beams can be ensured reliably, and the in-plane illuminance of the illuminated area can be made more uniform in the image forming area of the light modulation device.

Here, when the light source including the arc tube and the reflecting mirror described above is used as the light source, the light emitting portion of the arc tube is ideally a point light source, but the reality is finite. The divided partial light beams form a plurality of light source images having a substantially oval shape or a substantially oval shape on the second lens array. Among these light source images, the light source image near the central axis of the illumination light beam has a high illumination intensity, and the light source image near the outer edge tends to have a low illumination intensity.
Therefore, in the longitudinal direction of the polarization separation layer of the polarization conversion element, the light source image closer to the central axis of the illumination light beam has a higher illumination intensity, and the slit becomes closer to the central axis of the light shielding member in the longitudinal direction of the polarization separation layer. By reducing the width of the aperture formed in a shape, the amount of partial light that forms a light source image with higher illumination intensity can be reduced, and the total amount of illumination light that illuminates the image forming area of the light modulator can be reduced. Can be reduced. Thereby, the contrast of the optical image projected by the projector can be improved. That is, reducing the total amount of illumination light beam that irradiates the image forming area of the light modulation device to improve the contrast, and improve the unevenness of the projected image without reducing the number of partial light beams Can do.

Or in this invention, it is preferable that the said opening part is formed in multiple numbers along the longitudinal direction of the said polarization separation layer.
According to the present invention, it is possible to achieve the same effect as the light shielding member having the opening formed in the slit shape described above. That is, since a plurality of openings are formed in the light shielding member along the longitudinal direction of the polarization separation layer, even when the light shielding member is rotated by the light shielding member so as to close the optical path of the illumination light beam, A part of each partial light beam emitted from the first lens array can be incident on the second small lens of the second lens array through the plurality of openings. According to this, the illumination light beam incident on the image forming area of the light modulation device can be reduced, and the number of partial light beams incident on the second lens array can be prevented from being reduced. Irradiance unevenness of the projected optical image can be further improved.
The plurality of second small lenses of the second lens array are arranged along the longitudinal direction of the polarization separation layer, and a plurality of openings of the light shielding member are formed according to the arrangement of the second small lenses. As a result, the above-described effects can be achieved more strictly.

Further, even when the light shielding member is rotated so as to gradually block the optical path of the illumination light beam, each of the light emitted from the first lens array through the opening formed along the longitudinal direction of the polarization separation layer. A part of the partial luminous flux can be incident on the second lens array. Therefore, it is possible to perform dimming while suppressing a rapid variation in the illumination intensity of the illumination light beam that illuminates the image forming area of the light modulation device.
Furthermore, if the position of the opening formed in the light shielding member is formed in accordance with the position of the light source image formed on the second lens array, the amount of reduced light of each partial light beam emitted from the first lens array is closely measured. The partial light beams can be partially incident on the second small lens of the second lens array. Therefore, it is possible to reduce the illumination light beam incident on the image forming area of the light modulation device and to easily adjust the total light amount of the illumination light beam incident on the image forming area.

In the present invention, the plurality of openings are formed to become smaller toward the center of the light shielding member in either one of a longitudinal direction of the polarization separation layer and a direction substantially orthogonal to the longitudinal direction. Preferably it is.
According to the present invention, the same effect as the light shielding member having the opening formed so that the width becomes narrower toward the center of the light shielding member can be obtained.
That is, it is possible to increase the attenuation rate of the illumination light beam in the vicinity of the central axis having a high illumination intensity, thereby further reducing the illumination intensity of the illumination light beam incident on the image forming region of the light modulation device. Therefore, the contrast of the optical image projected by the projector can be further improved.

[1. First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
(1) Overall Configuration of Projector 1 FIG. 1 is a diagram schematically showing a schematic configuration of the projector 1.
The projector 1 modulates a light beam emitted from a light source according to image information to form an optical image, and enlarges and projects the formed optical image on a screen or the like. As shown in FIG. 1, the projector 1 includes an exterior case 2, a projection lens 3, an optical unit 4, a control board (not shown), and a power supply unit 5. The projector 1 also includes a cooling fan (not shown) for cooling the control board and the power supply unit 5.

The exterior case 2 is formed in a substantially rectangular parallelepiped shape with a synthetic resin or the like, and accommodates the projection lens 3, the optical unit 4, the control board, the power supply unit 5 and the like inside. Although not shown in detail, the outer case 2 has an upper case that constitutes the top, front, back, and side surfaces of the projector 1, and a lower case that constitutes the bottom, front, side, and back surfaces of the projector 1, respectively. The upper case and the lower case are fixed to each other with screws or the like. An operation panel (not shown) on which various buttons for operating the projector 1 are provided is provided on the upper surface of the upper case, and the operation panel is electrically connected to a control board described later. ing.
The exterior case 2 is not limited to being made of a synthetic resin, but may be formed of other materials, for example, a metal such as magnesium.

(2) Configuration of Optical Unit 4 The optical unit 4 optically processes the light beam emitted from the light source to form an optical image (color image) corresponding to the image information, and the optical unit 4 is illustrated via the projection lens 3. It is a unit that magnifies and projects onto a screen that does not. The optical unit 4 extends along the back surface of the outer case 2 and is configured in a substantially L shape in plan view that extends along the side surface of the outer case 2.
Among these, the projection lens 3 corresponds to the projection optical system of the present invention, and although not shown in detail, is configured as a combined lens in which a plurality of lenses are housed in a lens barrel. The projection lens 3 enlarges and projects a color image formed by an electro-optical device 44 described later.

As shown in FIG. 1, the optical unit 4 includes an integrator illumination optical system 41, a color separation optical system 42, a relay optical system 43, an electro-optical device 44, and an optical component housing these optical components 41 to 44. And a housing 46. The optical components 41 to 44 are positioned and adjusted in the optical component casing 46 in which the illumination optical axis A that is the central axis of the illumination light beam is set.
Of these, the optical component casing 46 is not shown in detail, but is composed of a component storage member that is open at the top and formed in a box shape, and a lid-shaped member that covers the opening of the component storage member. . A large number of groove portions are formed in the component storage member, and the optical components 412 to 414, 421 to 423, and 431 to 434 are fitted into these grooves, so that each optical component becomes a component storage member. Stored.

  The integrator illumination optical system 41 is an illumination optical system for illuminating an image forming area of a liquid crystal panel 441 described later of the electro-optical device 44 substantially uniformly. The integrator illumination optical system 41 includes a light source device 411, a first lens array 412, a second lens array 413, a polarization conversion device 414, a superimposing lens 415, and a dimming device 45.

The light source device 411 includes a light source lamp 416 that is a discharge light source that emits a radial light beam, a reflector 417 that reflects radiation light emitted from the light source lamp 416, and a parallel beam that collimates the light beam emitted from the reflector 417. And a conversion lens 418.
In the present embodiment, the light source lamp 416 employs a high-pressure mercury lamp, but is not limited thereto, and a halogen lamp, a metal halide lamp, or the like can be employed. Moreover, although the reflector 417 employ | adopts the ellipsoidal mirror in this embodiment, it is good also as a structure which employ | adopts a parabolic mirror. In this case, the collimating lens 418 can be omitted.

The first lens array 412 has a configuration in which a plurality of first small lenses having a substantially rectangular outline as viewed from the direction along the illumination optical axis A are arranged in a matrix. The plurality of first small lenses divide the light beam emitted from the light source device 411 into a plurality of partial light beams.
The second lens array 413 has a function of superimposing the partial light beams emitted from the first lens array 412 on a liquid crystal panel 441 described later of the electro-optical device 44 together with the superimposing lens 415. The second lens array 413 has a configuration similar to that of the first lens array 413, and a plurality of second small lenses corresponding to the first small lenses in the first lens array 412 are arranged in a matrix. It has a configuration. The plurality of second small lenses are arranged along the longitudinal direction of the polarization separation layer 4711 of the polarization conversion element 414 described later. In each second small lens, a light source image is formed by a partial light beam emitted from the light source device 411 and divided by the first lens array 412. This light source image is formed corresponding to the position of each small lens of the second lens array 413.
The dimming device 45 is disposed between the first lens array 412 and the second lens array 413, and a detailed configuration will be described in detail later.

FIG. 2 is an exploded perspective view showing the structure of the polarization conversion device 414.
The polarization conversion device 414 corresponds to the polarization conversion element of the present invention, is disposed between the second lens array 413 and the superimposing lens 415, and converts the light beam emitted from the second lens array 413 into one kind of linearly polarized light. To convert. As shown in FIG. 2, the polarization conversion device 414 includes a polarization conversion unit 47 that emits the partial light beams emitted from the second small lenses of the second lens array 413 so as to be aligned with one type of linearly polarized light, and the polarization A light shielding plate 48 provided on the light incident side of the conversion unit 47 is provided.
Among these, the polarization conversion unit 47 is attached to the light beam exit side of the polarization separation element array 471 and is separated from the polarization beam separation element array 471 that separates the incident light beam into two types of linearly polarized light and emits it. Among the two types of light beams emitted from the element array 471, a retardation plate 472 is provided that rotates the polarization axis of one linearly polarized light by 90 ° to be the same as the polarization axis of the other linearly polarized light.

FIG. 3 is a partially enlarged cross-sectional view of the polarization conversion device 414.
As shown in FIG. 3, the polarization separation element array 471 includes a polarization separation layer 4711 and a reflection layer 4712 that are inclined at about 45 ° with respect to the illumination optical axis A and are alternately arranged, and the polarization separation layer 4711 and the reflection layer. A glass member 4713 on which a layer 4712 is formed. As shown in FIG. 2, the polarization separation layer 4711 and the reflection layer 4712 have a longitudinal direction in a direction (arrow C in FIG. 2) orthogonal to the direction in which they are alternately arranged (arrow B in FIG. 2). It is a shape.

The polarization separation layer 4711 is a layer that separates a randomly polarized light beam into two types of linearly polarized light, and is configured by a dielectric multilayer film that transmits one polarized light of the incident light beam and reflects the other polarized light. ing.
The reflective layer 4712 is a layer that reflects the polarized light reflected by the polarization separation layer 4711 toward the light beam exit side of the polarization conversion device 414, and is configured by a reflective film formed of a single metal material, an alloy, or the like. Has been.
The glass member 4713 transmits the light beam inside, and in this embodiment, the glass member 4713 is formed by processing white plate glass or the like.

As shown in FIG. 3, the phase difference plate 472 is provided on the light beam exit side of the glass member 4713 constituting the polarization separation element array 471, and one of the two types of linearly polarized light emitted from the polarization separation element array 471 is displayed. The polarization direction of the linearly polarized light is rotated by 90 ° to be the same as the polarization direction of the other linearly polarized light.
Specifically, the phase difference plate 472 is attached to a portion of the light beam exit end face of the polarization separation element array 471 where linearly polarized light transmitted through the polarization separation layer 4711 is emitted, and the straight line transmitted through the polarization separation layer 4711. The polarization direction of polarized light is rotated by 90 °.

The light shielding plate 48 is disposed on the light beam incident side of the polarization separation element array 471. The light shielding plate 48 includes a plate-like body 481 formed of stainless steel or aluminum alloy, and an opening 482 is formed in the plate-like body 481 corresponding to the polarization separation layer 4711 of the polarization separation element array 471. ing. For this reason, since the opening corresponding to the reflective layer 4712 of the polarization separating element array 471 is not formed in the plate-like body 481, the partial light beams emitted from the first lens array 412 and the second lens array 413 are The light does not enter the reflective layer 4712.
In other words, the light shielding plate 48 is configured so that the partial light beams emitted from the first lens array 412 and the second lens array 413 are incident only on the polarization separation layer 4711, and unnecessary light incident on the reflection layer 4712 is not generated. Are blocked by the light shielding plate 48. Therefore, most of the partial light beams emitted from the second lens array 413 pass through the opening 482 of the light shielding plate 48 and enter the polarization separation layer 4711.

A case where the polarization separation layer 4711 of the polarization conversion device 414 described above transmits P-polarized light and reflects S-polarized light will be described with reference to FIG.
The partial light beam emitted from the second lens array 413 passes through the opening 482 of the plate-like body 481 constituting the light shielding plate 48 and enters the polarization separation layer 4711 of the polarization separation element array 471. The polarization separation layer 4711 transmits the P-polarized light contained in the partial light flux and reflects the S-polarized light toward the reflection layer 4712 so as to change the optical path by 90 °.
Here, the S-polarized light incident on the reflective layer 4712 is reflected by the reflective layer 4712 so that the optical path is converted by 90 ° toward the light beam exit side, and travels in substantially the same direction as the illumination optical axis A.
On the other hand, the P-polarized light that has passed through the polarization separation layer 4711 is incident on the phase difference plate 472, and the polarization direction is rotated by 90 ° by the phase difference plate 472, and is emitted as S-polarized light.
As a result, approximately one type of S-polarized light is emitted from the polarization conversion device 414.

Here, in a projector using a liquid crystal panel of a type that modulates linearly polarized light, only one type of linearly polarized light can be used, and therefore approximately half of the light emitted from the light source device 411 that emits randomly polarized light cannot be used. For this reason, in the present embodiment, by using the polarization conversion device 414, the light emitted from the light source device 411 is converted into substantially one type of linearly polarized light, and the use efficiency of light in the electro-optical device 44 is enhanced.
In this way, each partial light beam converted into approximately one type of linearly polarized light by the polarization conversion device 414 is placed on an image forming area (light modulation surface) of a liquid crystal panel 441 (to be described later) of the electro-optical device 44 by the superimposing lens 415. Is almost superimposed.

As shown in FIG. 1, the color separation optical system 42 includes two dichroic mirrors 421 and 422 and a reflection mirror 423, and is emitted from the integrator illumination optical system 41 by the dichroic mirrors 421 and 422. In addition, it has a function of separating a plurality of partial light beams into three color lights of red, green, and blue.
The relay optical system 43 includes an incident side lens 431, a relay lens 433, and reflection mirrors 432 and 434, and the red light separated by the color separation optical system 42 is a later-described red light side liquid crystal panel of the electro-optical device 44. 441 (441R).

  Here, the dichroic mirror 421 of the color separation optical system 42 reflects the blue light component and transmits the red light component and the green light component of the light beam emitted from the integrator illumination optical system 41. The blue light reflected by the dichroic mirror 421 is reflected by the reflection mirror 423 and then passes through the field lens 419 to reach a later-described liquid crystal panel 441 (441B) on the blue light side of the electro-optical device 44. The field lens 419 converts each partial light beam emitted from the second lens array 413 into a light beam parallel to each principal ray. The field lens 419 provided on the light beam incident side of the other liquid crystal panel 441 (441G, 441R) for green light and red light also has the same configuration and function.

Of the red light component and the green light component transmitted through the dichroic mirror 421, the green light component is reflected by the dichroic mirror 422, then passes through the field lens 419, and the later-described green light side liquid crystal panel 441 of the electro-optical device 44. (441G) is reached.
On the other hand, the red light component passes through the dichroic mirror 422, passes through the relay optical system 43 described above, and further passes through the field lens 419 to reach a later-described red light side liquid crystal panel 441 (441R) of the electro-optical device 44. .

Here, the relay optical system 43 is used for the red light component because the length of the optical path of the red light component is longer than the length of the optical path of the other color light components. This is to prevent a decrease in efficiency. That is, this is to transmit the partial light beam incident on the incident side lens 431 to the field lens 419 as it is.
In this embodiment, since the optical path length of the red light component is long, the relay optical system 43 is arranged on the optical path of the red light component. However, the optical path length of the blue light component is increased. Is also possible. In such a case, the relay optical system 43 may be disposed on the optical path of the blue light component.

  The electro-optical device 44 corresponds to an optical image forming system of the present invention, and forms a color image by modulating an incident light beam according to image information. The electro-optical device 44 includes three incident-side polarizing plates 442 on which the respective color lights separated by the color separation optical system 42 are incident, and liquid crystal panels 441 (441R, 441G) arranged at the subsequent stage of the incident-side polarizing plate 442. , 441B) and an exit-side polarizing plate 443, and a cross dichroic prism 444 as a color synthesizing optical device.

  The liquid crystal panels 441 (441R, 441G, 441B) correspond to the light modulation device of the present invention. Each of these liquid crystal panels 441 uses, for example, a polysilicon TFT as a switching element, and is composed of two translucent substrates arranged opposite to each other and a liquid crystal material hermetically sealed by these translucent substrates. And a liquid crystal layer. Each of the liquid crystal panels 441R, 441G, and 441B modulates and emits a light beam incident through the incident-side polarizing plate 442 according to image information.

The incident-side polarizing plate 442 transmits only linearly polarized light in a certain direction and absorbs other light beams among the respective color lights separated by the color separation optical system 42, and a polarizing film is provided on a substrate such as sapphire glass. It is what was done.
The exit side polarizing plate 443 is configured in the same manner as the incident side polarizing plate 442, and transmits only linearly polarized light in a predetermined direction among the light beams emitted from the liquid crystal panels 441R, 441G, and 441B, and absorbs other light beams. Therefore, the polarization axis of the linearly polarized light to be transmitted is set to be orthogonal to the polarization axis of the linearly polarized light to be transmitted in the incident side polarizing plate 442.

  The cross dichroic prism 444 combines the optical images emitted from the emission-side polarizing plate 443 and modulated for each color light to form a color image. The cross dichroic prism 444 has three light incident surfaces and one light exit surface. The dielectric multilayer film that reflects red light and the dielectric multilayer film that reflects blue light are four. It is provided in a substantially X shape along the interface of two right-angle prisms. Therefore, the red light that has passed through the liquid crystal panel 441R and entered the light incident surface for red light is reflected toward the light exit surface by the dielectric multilayer film that reflects the red light, and is transmitted through the liquid crystal panel 441B. The blue light incident on the blue light beam incident surface is reflected toward the light beam emission surface by the dielectric multilayer film that reflects the blue light. Here, since the green light that has passed through the liquid crystal panel 441G and entered the light incident surface for green light is not reflected by these dielectric multilayer films, it passes through the X-shaped dielectric multilayer film and enters the light flux exit surface. To reach. In this process, the three color lights are combined, and the combined light beam is emitted as an optical image from the light beam emission surface.

(3) Configuration of Control Board and Power Supply Unit 5 The control board controls the entire apparatus of the projector 1 and is configured as a circuit board including a CPU (Central Processing Unit) and the like. The control board processes image information input from a device connected to the projector 1 to control the driving of the liquid crystal panel 441 of the electro-optical device 44, and also controls the luminance and dimming of the light source lamp 416 by the power supply unit 5. Drive control of the device 45 is performed.
The power supply unit 5 converts an alternating current input from an external power source into a direct current, converts the direct current into a predetermined voltage corresponding to an electronic component constituting the apparatus main body, and supplies the converted voltage to the electronic component. In addition, the power supply unit 5 generates an AC rectangular wave current from the DC current and supplies it to the light source lamp 416 constituting the light source device 411 described above. The power supply unit 5 is electrically connected to the control board, and drive power supply control to the light source lamp 416 and accompanying lighting control of the light source lamp 416 are performed by the control board.

(4) Configuration of the dimming device 45 FIG. 4 is a layout diagram when the integrator illumination optical system 41 is viewed from above. FIG. 5 is a layout diagram when the integrator illumination optical system 41 is viewed from the horizontal direction. The dotted lines shown in FIGS. 4 and 5 indicate a part of the plurality of partial light beams divided by the first lens array 412.
As described above, the integrator illumination optical system 41 includes the dimming device 45, and the dimming device 45 is disposed between the first lens array 412 and the second lens array 413.
The dimming device 45 corresponds to the diaphragm mechanism of the present invention, and is emitted from the light source device 411 through the first lens array 412 in the state where the dimming device 45 most attenuates the illumination light beam. Are partially shielded from light, and light incident on the second lens array 413 is reduced.
As shown in FIGS. 4 and 5, the dimming device 45 includes a pair of light shielding plates 451 and 452 having rotating shafts 4511 and 4521 substantially parallel to the direction orthogonal to the illumination optical axis A, and the light shielding plates 451 and 451. Rotating means (not shown) that rotates 452 around the respective rotating shafts 4511 and 4521 is provided.
Among these, a stepping motor etc. can be illustrated as a rotation means.

The light shielding plates 451 and 452 correspond to the light shielding members of the present invention, and are arranged at symmetrical positions with a predetermined interval around the illumination optical axis A of the light beam emitted from the light source device 411 as shown in FIG. Has been. These light shielding plates 451 and 452 are arranged symmetrically with respect to the illumination optical axis A.
Further, the light shielding plates 451 and 452 are rotated about the rotation shafts 4511 and 4521 by the rotation means, respectively, and diminish the incident light beam to the second lens array 413. More specifically, the light shielding plates 451 and 452 have a position substantially parallel to the second lens array 413 at 0 °, and the tip portions of the light shielding plates 451 and 452 near the illumination optical axis A are located on the first lens array 412. It rotates in the vertical direction in FIG. In other words, when the light shielding plates 451 and 452 rotate, the tip portions of the respective light shielding plates 451 and 452 move in the vertical direction in FIG. 5 when viewed from the illumination optical axis A direction. For this reason, the illumination intensity of the incident light beam on the second lens array 413 can be finely adjusted by adjusting the rotation angle of the light shielding plates 451 and 452.

FIG. 6 is a view of the light shielding plates 451 and 452 as seen from the first lens array 412 side along the direction of the illumination optical axis A, and is formed on the light shielding plates 451 and 452 and the second lens array 413. It is a figure which shows the positional relationship with a light source image.
As shown in FIG. 6, the light shielding plates 451 and 452 have a substantially rectangular shape when viewed from the direction along the illumination optical axis A. The light shielding plates 451 and 452 have slit-shaped openings 4512 and 4522. A plurality are formed.
Here, as described above, most of the plurality of partial light beams that have passed through the first lens array 412 and the second lens array 413 are incident on the polarization separation layer 4711 of the polarization conversion device 414. For this reason, the light source images of the plurality of partial light beams are arranged close to each other along the longitudinal direction of the polarization separation layer 4711 on the second lens array 413, and the arrows in FIG. 6 match the arrangement of the polarization separation layers 4711. A plurality are formed in the B direction. The plurality of second small lenses of the second lens array 413 are arranged in rows and columns according to the position where the light source image is formed.

The openings 4512 and 4522 of the light shielding plates 451 and 452 rotate to positions where the light shielding plates 451 and 452 are substantially parallel to the second lens array 413, that is, positions where the light shielding plates 451 and 452 are most dimmed. In a moved state, the light beam is formed along a row of light source images formed on the second lens array 413 so that a part of light is transmitted for each partial light beam incident on the light shielding plates 451 and 452. In other words, each of the openings 4512 and 4522 is formed in a slit shape along the arrangement direction of the small lenses of the second lens array 413 in which the light source images formed by the partial light beams are arranged. The small lenses of the second lens array 413 are arranged along the longitudinal direction (the direction of arrow C in FIG. 6) of the polarization separation layer 4711 of the polarization conversion device 414.
The light shielding plates 451 and 452 are arranged such that the axial directions of the rotation shafts 4511 and 4521 of the light shielding plates 451 and 452 are along the direction orthogonal to the longitudinal direction of the polarization separation layer 4711.

  Accordingly, the opening portions 4512 and 4522 of the light shielding plates 451 and 452 are formed in a direction substantially orthogonal to the axial direction B of the rotation shafts 4511 and 4521 of the light shielding plates 451 and 452, respectively. The formation position of 4522 corresponds to the column direction of the light source image LI formed on the second lens array 413. The openings 4512 and 4522 are notched on the side opposite to the rotation shafts 4511 and 4521. That is, the ends on the illumination optical axis A side of the openings 4512 and 4522 of the respective light shielding plates 451 and 452 are notched, and the respective light shielding plates 451 and 452 are formed in a substantially comb shape.

While the light shielding plates 451 and 452 as described above rotate from a position substantially perpendicular to the second lens array 413 to a position substantially parallel to the second lens array 413, that is, the light shielding plate 451. , 452 rotate from the position where the illumination light beam is not dimmed to the position where it is most dimmed, and each part emitted from the first lens array 412 is always from the openings 4512, 4522 of the light shielding plates 451, 452. A part of the light for each light beam is transmitted, and the light enters the polarization separation layer 4711 of the polarization conversion device 414.
For this reason, the light source image formed on the second lens array 413 is increased when the illumination light beam is dimmed as compared to the case where the partial light beam is gradually shielded when the illumination light beam is dimmed, such as a light shielding plate without an opening. can do. Therefore, even when the light shielding plates 451 and 452 rotate to diminish the illumination light beam, the number of partial light beams superimposed on the liquid crystal panel 441 by the second lens array 413 and the superimposing lens 415 does not change.

  FIG. 7 is a graph showing the illumination intensity of the incident light beam on the second lens array 413 with respect to the rotation angle of the light shielding plates 451 and 452. In FIG. 7, the solid line is a graph when the light shielding plates 451 and 452 of the present embodiment are used. Moreover, the broken line has shown the graph at the time of using a pair of light shielding plate in which the opening part is not formed as a prior art example. In the conventional example, the interval between the respective light shielding plates is slightly larger than the interval between the light shielding plates 451 and 452 of this embodiment, so that the rotation angle of the light shielding plate is 0 °, that is, the light shielding plate is closed. The illumination intensity in the case of being present is substantially the same as the illumination intensity in the case where the light shielding plates 451 and 452 of the present embodiment are closed.

When the partial light beams emitted from the first lens array 412 are attenuated using the dimming device 45 of the present embodiment, as shown in FIG. 7, the second lens is compared with the case of using a conventional light shielding plate. It can be suppressed that the illumination intensity of the light beam incident on the array 413 fluctuates rapidly.
On the other hand, the light source image LI formed on each second small lens of the second lens array 413 tends to have higher illumination intensity toward the vicinity of the illumination optical axis A, and lower illumination intensity toward the outer edge. As shown in FIG. 6, the light source image LI formed in the vicinity of the illumination optical axis A has a substantially oval shape larger than the light source image LI formed in the vicinity of the outer edge.
That is, in this embodiment, as shown in FIG. 6, the light source image LI formed on the second lens array 413 is the column direction of the second lens array 413 (the longitudinal direction of the polarization separation layer 4711 of the polarization conversion device 414). The illumination intensity of the light source image is higher along the column and row centers of the second lens array 413 when viewed from the direction along the illumination optical axis A. Also, the illumination intensity is higher in the light source image near the outer edge in the row direction in the center than in the light source image near the outer edge in the column direction in the center. For this reason, when the light shielding plates 451 and 452 are gradually reduced from the fully opened state (rotation angle 90 °), the light shielding plates 451 and 452 are placed on the optical path when the rotation angle is approximately 60 °. Intervening is started, dimming is started, and the illumination intensity of the light beam incident on the second lens array 413 is lowered.

On the other hand, the end portions of the light shielding plates 451 and 452 on the side close to the illumination optical axis A of the openings 4512 and 4522 are notched, and the rotation direction of the light shielding plates 451 and 452 is the illumination optical axis. Since it is the vertical direction, that is, the column direction (longitudinal direction of the polarization separation layer 4711 of the polarization conversion device 414) when viewed from the direction along A, a part of each partial light beam from both outer edge portions in the column direction toward the center portion. It is possible to shield light from other parts while transmitting the light.
Here, in the case of using a conventional light shielding plate in which no opening is formed, since all light of each partial light beam is sequentially shielded from both outer edge portions toward the central portion, the light shielding plate at the outer edge portion. The amount of rotation and the amount of light to be shielded are significantly different from the amount of rotation of the light shielding plate at the center and the amount of light to be shielded. To do.

Here, temporarily, the rotation shafts 4511 and 4521 of the light shielding plates 451 and 452 are arranged in the direction along the longitudinal direction of the polarization separation layer 4711 of the polarization conversion device 414, and the rotation direction of the light shielding plates 451 and 452 is When viewed from the direction along the illumination optical axis A, the horizontal direction, that is, the row direction (the direction perpendicular to the longitudinal direction of the polarization separation layer 4711) is set. In this case, when the light shielding plates 451 and 452 pass through the corresponding portions between the rows of partial light beams, that is, when the portions that hardly block the partial light beams are rotated, the partial light beams The ratio between the rotation angle of the light shielding plates 451 and 452 and the amount of reduced light of the illumination light beam varies in the portion corresponding to the column, that is, when the light beam is rotated while shielding the partial light beam.
Therefore, in the case where the dimming device 45 of the present embodiment is used, the dimming rate of the light beam incident on the second lens array 413 is abrupt as compared with the case where a conventional light shielding plate having no opening is formed. Variations can be suppressed. In particular, the suppression of the fluctuation of the light attenuation rate can provide a remarkable result when the rotation angles of the light shielding plates 451 and 452 are in a range of approximately 60 ° to approximately 50 ° and approximately 35 ° to approximately 20 °.

Further, the dimming device 45 includes a pair of light shielding plates 451 and 452 that are arranged substantially symmetrically about the illumination optical axis A. According to this, it is possible to easily adjust the dimming rate of the light beam incident on the second lens array 413 as compared with the case where light is shielded by one light shielding plate.
That is, when the light is reduced by one light shielding plate, the illumination light on the side where the light shielding plate is arranged as the light shielding plate is interposed on the optical path of the illumination light beam emitted from the first lens array. The luminous flux on the outer edge of the axis A, the luminous flux in the vicinity of the illumination optical axis A, and the luminous flux on the outer edge of the illumination optical axis A on the side opposite to the side where the light shielding plate is arranged are sequentially shielded. In such a case, it is difficult to finely adjust the attenuation rate of the light beam in the vicinity of the illumination optical axis A having a high illumination intensity. As a result, the illumination intensity of the light beam incident on the second lens array 413 changes rapidly. In addition, the illuminance distribution with respect to the illumination optical axis A of the illumination light flux incident on the second lens array 413 becomes uneven.

  On the other hand, when light is reduced by a pair of light shielding plates 451 and 452 arranged substantially symmetrically about the illumination optical axis A, the light shielding plates 451 and 452 rotate the light beams near the illumination optical axis A. As the second lens array 413 approaches approximately parallel, that is, as the rotation angle of the light shielding plates 451 and 452 approaches 0 °, the light is gradually shielded. According to this, since it is possible to suppress the light beam in the vicinity of the optical axis A having high illumination intensity from being suddenly shielded, it is possible to finely adjust the light attenuation rate. Further, the illuminance distribution of the illumination light beam incident on the second lens array 413 with respect to the illumination optical axis A becomes substantially uniform, and the uniformity of the in-plane illuminance of the illumination light beam that illuminates the image forming area of the liquid crystal panel 441 is further impaired. Fine dimming adjustment can be realized.

FIG. 8 is a graph showing the illuminance ratio of the projected image when the light shielding plates 451 and 452 are fully opened and closed. In FIG. 8, the solid line is a graph when the light shielding plates 451 and 452 are closed (rotation angle 0 °), and the dotted line is a graph when the light shielding plates 451 and 452 are fully opened (rotation angle 90 °). Moreover, the broken line has shown the graph of the illumination intensity ratio at the time of obstruct | occluding a pair of light shielding plate in which the opening part is not formed as a prior art example.
By using the light shielding plates 451 and 452 as described above, the in-plane illuminance of the projected image is improved even when the light beam incident on the second lens array 413 is dimmed as follows.
That is, when the light beam incident on the second lens array 413 is reduced using the light shielding plates 451 and 452, the projected image is compared with the case where the conventional light shielding plate indicated by the broken line is employed as shown in FIG. It is possible to make the illuminance ratio near the both ends close to the illuminance ratio near the center. Further, the illuminance ratio of the projected image when the light shielding plates 451 and 452 are closed (rotation angle 0 °) is the state in which the light shielding plates 451 and 452 are fully opened (rotation angle 90 °), that is, the light is reduced. The illuminance ratio can be almost the same as in the case of no.
Therefore, when the light shielding plates 451 and 452 of the present embodiment are used, as shown in FIG. 7, a sudden change in the light flux incident on the second lens array 413 with respect to the rotation angle of the light shielding plates 451 and 452 is caused. As shown in FIG. 8, the illuminance ratio of the projected image can be improved as compared with the conventional light shielding plate, thereby suppressing unevenness in the illuminance of the projected image. Can do.

[2. Second Embodiment]
Next, a projector according to a second embodiment of the invention will be described.
The projector according to the second embodiment has the same configuration as that of the projector 1 according to the first embodiment described above, but differs in the shape of the opening of the light shielding plate constituting the dimming device 45. In the following description, parts that are the same as or substantially the same as those already described are assigned the same reference numerals and description thereof is omitted.

FIG. 9 is a view of the light shielding plates 453 and 454 according to the second embodiment of the present invention as seen from the direction along the illumination optical axis A, and is also on the light shielding plates 453 and 454 and the second lens array 413. It is a figure which shows the positional relationship with the light source image LI formed. 9 is the same as the axial direction B of the rotation shafts 4511 and 4521 of the light shielding plates 451 and 452 shown in FIG.
Although the detailed illustration of the light shielding plates 453 and 454 is omitted, the row direction of the second lens array 413 (the direction orthogonal to the longitudinal direction of the polarization separation layer 4711 of the polarization conversion device 414) is similar to the light shielding plates 451 and 452. ) Along the rotation shafts 4531 and 4541, which are rotated by the rotation means around the rotation shafts 4531 and 4541 so as to block a part of each partial light beam emitted from the first lens array 412. Then, the illumination light beam incident on the second lens array 413 is dimmed. The rotation directions of the light shielding plates 453 and 454 are set so as to follow the arrangement direction of the light source images formed on the second lens array 413. In this embodiment, the rotation direction of the light shielding plates 453 and 454 is the vertical direction when viewed from the direction along the illumination optical axis A, that is, the column direction of each second small lens of the second lens array 413 (polarized light). It is configured to rotate in the longitudinal direction of the separation layer 4711.

  A plurality of openings 4532 and 4542 having a substantially circular shape in plan view are formed in the light shielding plates 453 and 454. More specifically, these openings 4532 and 4542 are arranged in the column direction of each second small lens (the polarization separation layer 4711 of the second lens array 413) when the light shielding plates 453 and 454 are closed (rotation angle 0 °). (Longitudinal direction) is formed at a position corresponding to each light source image LI formed on the second lens array 413. The openings 4532 and 4542 are formed to be smaller than the size of each second small lens of the second lens array 413.

FIG. 10 is a graph showing the illumination intensity of the incident light beam on the second lens array 413 with respect to the rotation angle of the light shielding plates 453 and 454. In FIG. 10, the solid line is a graph when the light shielding plates 453 and 454 of the present embodiment are used. Moreover, the broken line has shown the graph at the time of using a pair of light shielding plate in which the opening part is not formed as a prior art example.
By using such light shielding plates 453 and 454 to reduce the light beam incident on the second lens array 413, the same effect as when light is reduced using the light shielding plates 451 and 452 described above can be obtained. Can do.

That is, when the light shielding plates 453 and 454 are rotated from the fully open (rotation angle 90 °) state to block the optical path of the illumination light beam emitted from the first lens array 412, the light shielding plates 453 and 454 are formed. A part of each partial light beam can be partially incident on the second lens array 413 through the openings 4532 and 4542 formed. As a result, the openings formed in the light shielding plates 453 and 454 are not suddenly shielded from the light beam forming the light source image with high illumination intensity, as in the case of using a conventional light shielding plate in which no opening is formed. The light flux can be partially incident on the second lens array 413 via the portions 4532 and 4542.
Accordingly, in FIG. 10, the light flux incident on the second lens array 413 is reduced so that the rotation angles of the light shielding plates 453 and 454 are in the range of approximately 60 ° to approximately 50 ° and approximately 35 ° to approximately 20 °. When the light shielding plates 453 and 454 are used for the light, it is possible to suppress a rapid change in the illumination intensity of the light flux incident on the second lens array 413.

FIG. 11 is a graph showing the illuminance ratio of the projected image when the light shielding plates 453 and 454 are fully opened and closed. In FIG. 11, the solid line and the dotted line are graphs of the closed state (rotation angle 0 °) and the fully open state (rotation angle 90 °) of the light shielding plates 453 and 454, and the broken line indicates a conventional opening. The graph of the state which obstruct | occluded a pair of light-shielding plates which are not shown is shown.
Even when the light beam emitted from the first lens array 412 is shielded by using the light shielding plates 453 and 454 to reduce the light beam incident on the second lens array 413, even when the light shielding plates 453 and 454 are closed. Through the openings 4532 and 4542, a light beam can be incident on each small lens of the second lens array 413. Here, the openings 4532 and 4542 formed in the light shielding plates 453 and 454 are formed according to the plurality of light source images LI formed on the second lens array 413 along the column direction of the second lens array 413. Therefore, even when the light shielding plates 453 and 454 are closed, a plurality of partial light beams can be reliably incident on each second small lens of the second lens array 413.

  Accordingly, the number of partial light beams incident on the second lens array 413 at the time of dimming can be increased as compared with the case of using a light shielding plate having no conventional opening. Further, as shown in FIG. 11, the in-plane illuminance of the projected image when the light shielding plates 453 and 454 are closed can be improved, and uneven illuminance of the projected image can be suppressed. Even in such a case, since the openings 4532 and 4542 are formed to be smaller than the small lenses of the second lens array 413, the light flux incident on the second lens array 413 as shown in FIG. Can be surely dimmed.

[3. Third Embodiment]
Next, a projector according to a third embodiment of the invention will be described.
The projector according to the third embodiment has the same configuration as the projector 1 according to the first embodiment described above, but differs in the shape of the opening of the light shielding plate that constitutes the light reduction device 45. In the following description, parts that are the same as or substantially the same as those already described are assigned the same reference numerals and description thereof is omitted.

FIG. 12 is a view of the light shielding plates 455 and 456 according to the third embodiment of the present invention as seen from the direction along the illumination optical axis A, and is also on the light shielding plates 455 and 456 and the second lens array 413. It is a figure which shows the positional relationship with the light source image LI formed. 12 is the same as the axial direction B of the rotation shafts 4511 and 4521 of the light shielding plates 451 and 452 shown in FIG. 6 described above. Yes, the direction orthogonal to the longitudinal direction of the polarization separation layer 4711 of the polarization conversion device 414.
The light shielding plates 455 and 456 are disposed substantially symmetrically with a predetermined distance from the illumination optical axis A. The light shielding plates 455 and 456 are formed with a plurality of slit-shaped openings 4552 and 4562 as shown in FIG.

These openings 4552 and 4562 are formed in the light source image LI formed on the second lens array 413 along the column direction of each second small lens of the second lens array 413 (longitudinal direction of the polarization separation layer 4711). A plurality of rows are formed accordingly. That is, the openings 4552 and 4562 transmit a part of light for each partial light beam incident on the second lens array 413 when the light shielding plates 455 and 456 are in a closed state (rotation angle 0 °). It is formed as follows.
Each of the openings 4552 and 4562 is notched on the opposite side to the rotation shafts 4551 and 4561 of the light shielding plates 455 and 456 in the same manner as the openings 4552 and 4562 of the light shielding plates 455 and 456 described above.
In addition, the formation direction of the openings 4552 and 4562 of the light shielding plates 455 and 456 is a direction substantially orthogonal to the axial direction of the rotation shafts 4551 and 4561 of the light shielding plates 455 and 456.

By using the light shielding plates 455 and 456 as described above, it is possible to achieve the same effects as when the above-described light shielding plates 451 and 452 are used.
FIG. 13 is a graph showing the illumination intensity of the incident light beam on the second lens array 413 with respect to the rotation angle of the light shielding plates 455 and 456. In FIG. 13, the solid line is a graph when the light shielding plates 455 and 456 of the present embodiment are used. Moreover, the broken line has shown the graph at the time of using a pair of light shielding plate in which the opening part is not formed as a prior art example.
When the light shielding plates 455 and 456 of the present embodiment are used, as shown in FIG. 13, the light is emitted from the first lens array 412 as the light shielding plates 455 and 456 are closed from the fully open state (rotation angle 90 °). Since the light shielding plates 455 and 456 are interposed on the optical path of the luminous flux, the luminous flux incident on the second lens array 413 can be dimmed.

Here, a plurality of slit-shaped openings 4552 and 4562 are formed on the light shielding plates 455 and 456 in accordance with the small lenses of the second lens array 413, so that the openings 4552 and 4562 pass through the openings 4552 and 4562, respectively. Since some of the partial light beams incident on the light shielding plates 455 and 456 are transmitted toward the second lens array 413, the light beam with high illumination intensity incident on the second lens array 413 is rapidly reduced. Can be prevented.
Therefore, especially when the rotation axis of the light shielding plates 455 and 456 is in the range of approximately 60 ° to 50 ° and 35 ° to 20 °, a rapid change in the light attenuation rate associated with the rotation of the light shielding plates 455 and 456 is suppressed. It is possible to set the dimming rate finely.

As a result, even when the light shielding plates 455 and 456 are rotated to diminish the light beam incident on the second lens array 413, a part of each partial light beam is always transmitted through the light shielding plates 455 and 456, The light enters the two-lens array 413. In addition, since the rotation shafts 4551 and 4561 are arranged along the direction orthogonal to the longitudinal direction of the polarization separation layer 4711, the reduction of each partial light beam is performed in order from the outer edge portion to the center portion of the row where the light source images are continuous. Since light can be emitted, it is possible to prevent abrupt dimming of the light flux incident on the second lens array 413, and fine adjustment of the dimming rate can be performed.
Further, the openings 4552 and 4562 are seen from the direction along the illumination optical axis A, as they go toward the center of the second lens array 413, in other words, as they move away from the rotating shafts 4551 and 4561, the openings 4552 and 4562 are formed so that the width (dimension in the row direction) is reduced. According to this, when the light shielding plates 455 and 456 are closed, more light beams in the vicinity of the illumination optical axis A forming the light source image LI with high illumination intensity are shielded, and the light shielding plates 451 and 452 shown in the first embodiment are protected. Compared with the case of using, the contrast of a projection image can be improved.

FIG. 14 is a graph showing the illuminance ratio of the projected image when the light shielding plates 455 and 456 are fully opened and closed. In FIG. 14, the solid line and the dotted line are graphs of the light shielding plates 455 and 456 in the closed state (rotation angle 0 °) and the fully open state (rotation angle 90 °), and the broken line indicates a conventional opening. The graph of the state which obstruct | occluded a pair of light-shielding plates which are not shown is shown.
At the time of dimming by the light shielding plates 455 and 456, a part of each partial light beam emitted from the first lens array 412 is transmitted without being shielded through the openings 4552 and 4562 formed in the light shielding plates 455 and 456. Then, it enters each small lens of the second lens array 413. According to this, it is possible to prevent the number of partial light beams incident on the second lens array 413 from being reduced when light is reduced by the light shielding plates 455 and 456. For this reason, the illuminance ratio of the light beam superimposed on the liquid crystal panel 441 can be improved as compared with the conventional light shielding plate, and when the light shielding plates 455 and 456 are closed (rotation angle 0 °) as shown in FIG. The in-plane illuminance of the projected image can be made uniform to the same extent as when the light is not reduced, that is, when the light shielding plates 455 and 456 are fully opened (rotation angle 90 °). Therefore, in comparison with the prior art, the in-plane illuminance at the time of dimming of the light flux incident on the second lens array 413 can be improved, and uneven illuminance in the projected image can be suppressed.

[4. Fourth Embodiment]
Next, a projector according to a fourth embodiment of the invention will be described.
The projector according to the fourth embodiment has the same configuration as the projector 1 according to the second embodiment described above, but differs in the shape of the opening of the light shielding plate. In the following description, parts that are the same as or substantially the same as those already described are assigned the same reference numerals and description thereof is omitted.

FIG. 15 is a view of the light shielding plates 457 and 458 according to the fourth embodiment of the present invention as viewed from the direction along the illumination optical axis A, and also on the light shielding plates 457 and 458 and the second lens array 413. It is a figure which shows the positional relationship with the light source image LI formed. The axial direction B of the rotation shafts 4571 and 4581 of the light shielding plates 457 and 458 shown in FIG. 15 is the same as the axial direction B of the rotation shafts 4511 and 4521 of the light shielding plates 451 and 452 shown in FIG. This is a direction orthogonal to the longitudinal direction of the polarization separation layer 4711 of the polarization conversion device 414.
The light shielding plates 457 and 458 are arranged so as to be substantially symmetrical with a predetermined distance from the illumination optical axis A, similarly to the light shielding plates 451 to 456 described above. Further, as shown in FIG. 15, the light shielding plates 457 and 458 are formed with a plurality of openings 4572 and 4582 having a substantially elliptical shape in plan view.

These openings 4572 and 4582 form a light source image LI formed on the second lens array 413 along the column direction of each second small lens of the second lens array 413 (longitudinal direction of the polarization separation layer 4711). Multiple rows are formed according to the corresponding positions. That is, the openings 4572 and 4582 transmit a part of light for each partial light beam incident on the second lens array 413 when the light shielding plates 457 and 458 are in a closed state (rotation angle 0 °). It is formed as follows.
Each opening 4572 and 4582 is formed smaller than each second small lens of the second lens array 413. The openings 4572 and 4582 are formed larger in each row toward the side closer to the rotation shafts 4571 and 4581 of the light shielding plates 457 and 458, and the rotation shafts of the light shielding plates 457 and 458 among the plurality of rows. The axially central rows of 4571 and 4581 are formed smaller. That is, each of the openings 4572 and 4582 is formed smaller toward the illumination optical axis A.

For this reason, as the light shielding plates 457 and 458 are closed, the high intensity light flux in the vicinity of the illumination optical axis A is mostly shielded by the light shielding plates 457 and 458 and partly through the openings 4572 and 4582. The light enters the small lens of the two-lens array 413. On the other hand, a light beam with low illumination intensity in the vicinity of the outer edge is transmitted through the openings 4572 and 4582 without being shielded so much.
According to this, it is possible to block more light beams in the vicinity of the optical axis A forming the light source image LI with high illumination intensity and to transmit more light beams at the outer edge forming the light source image LI with low illumination intensity. Therefore, compared with the light shielding plates 453 and 454 shown in the second embodiment and the light shielding plates 455 and 456 shown in the third embodiment, the contrast of the projected image can be further improved.

By using the light shielding plates 457 and 458 as described above, it is possible to achieve the same effect as when the light shielding plates 455 and 456 shown in the third embodiment are used.
FIG. 16 is a graph showing the illumination intensity of the incident light beam on the second lens array 413 with respect to the rotation angle of the light shielding plates 457 and 458. In FIG. 16, the solid line is a graph when the light shielding plates 455 and 456 of the present embodiment are used. Moreover, the broken line has shown the graph at the time of using a pair of light shielding plate in which the opening part is not formed as a prior art example.
According to the light reduction device 45 provided with the light shielding plates 457 and 458 of the present embodiment, the light shielding plates 457 and 458 are rotated downward and upward when viewed from the direction along the illumination optical axis A, When the light beam emitted from the one lens array 412 is interposed on the optical path, the light beam can be incident on the second lens array 413 through the openings 4572 and 4582 positioned in the vicinity of the illumination optical axis A.
According to this, a light beam with high illumination intensity can be partially blocked, and a part of the light can be made incident on the second lens array 413, so that rapid dimming can be suppressed. In particular, as shown in FIG. 16, such dimming is prominent when the rotation angles of the light shielding plates 457 and 458 are approximately 60 ° to 50 ° and 35 ° to 20 °. Accordingly, it is possible to suppress a rapid variation in illumination intensity due to the dimming of the light beam incident on the second lens array 413.

FIG. 17 is a graph showing the illuminance ratio of the projected image when the light shielding plates 457 and 458 are fully opened and closed. In FIG. 17, the solid line and the dotted line are graphs of the light shielding plates 457 and 458 in the closed state (rotation angle 0 °) and the fully open state (rotation angle 90 °), and the broken line indicates a conventional opening. The graph of the state which obstruct | occluded a pair of light-shielding plates which are not shown is shown.
As described above, the light shielding plates 457 and 458 correspond to the plurality of light source images LI formed on the second lens array 413 in a state where the light shielding plates 457 and 458 are rotated until the illumination light beam is most dimmed. A plurality of rows of substantially elliptical openings 4572 and 4582 are formed at the positions. These openings 4572 and 4582 are formed smaller than each second small lens of the second lens array 413.

According to this, the light shielding plates 457 and 458 are rotated and incident on the second lens array 413 via the light shielding plates 457 and 458 on the optical path of the light beam emitted from the first lens array 412. Even when the light beam is dimmed, the partial light beam can be incident on the second lens array 413 without reducing the number of partial light beams emitted from the first lens array 412. For this reason, the number of partial light beams incident on the second lens array 413 can be increased as compared with the case where a light shielding plate having no conventional opening is used.
Therefore, as shown in FIG. 16, the light beam incident on the second lens array 413 can be dimmed without causing a rapid change in illuminance, and as shown in FIG. 17, it is emitted from the second lens array 413. The in-plane illuminance of the illumination area of the illumination light beam superimposed on the image formation in the liquid crystal panel 441 can be improved, and thereby uneven illuminance of the projected image can be suppressed.
In particular, the light beams incident on the second lens array 413 are reduced using such light shielding plates 457 and 458, so that the light shielding plates 457 and 458 are fully opened even when they are closed (rotation angle 0 °). An illumination ratio substantially the same as (rotation angle 90 °) can be realized.

[5. Modification of Embodiment]
The best configuration for implementing the present invention has been disclosed in the above description, but the present invention is not limited to this. That is, the description limited to the shape, material, etc. disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such is included in this invention.

  In each of the embodiments described above, the dimming device 45 includes the pair of light shielding plates 451 and 452, 453 and 454, 455 and 456, and 457 and 458. The number may be one or more. If the dimming device 45 includes at least a pair of light shielding plates, as described above, the illumination intensity of the light beam emitted from the first lens array 412 and incident on the second lens array 413 is set to While being able to adjust easily according to a rotation angle, it can suppress that the illumination intensity of the said incident light beam fluctuates rapidly, and it becomes possible to adjust the illumination intensity of the said incident light beam finely.

In the first and third embodiments, the openings 4512, 4522, 4552, and 4562 of the light shielding plates 451, 452, 455, and 456 are formed in a slit shape, and in the second and fourth embodiments, the light shielding is performed. Although the openings 4532, 4542, 4572, and 4582 of the plates 453, 454, 457, and 458 are formed in a substantially circular shape in plan view or a substantially elliptical shape in plan view, the present invention is not limited to this. That is, any shape may be used as long as the opening is formed so that at least a part of each partial light beam is transmitted according to the formation direction of each small lens of the second lens array 413.
In the second and fourth embodiments, the openings 4532, 4542, 4572, and 4582 of the light shielding plates 453, 454, 457, and 458 correspond to the arrangement of the light source images formed on the second lens array 413. The number is formed, but the number is not limited as long as it is one or more. Furthermore, even if the openings are scattered on the light shielding plate so that at least a part of each partial light beam is transmitted without being related to the position of the light source image formed on the second lens array 413. Good.

  In the first and third embodiments, the light shielding plates 451, 452, 455, and 457 are formed in a substantially comb-like shape in which the opposite side to the rotation shafts 4511, 4521, 4551, and 4571 is cut out. However, the present invention is not limited to this.

In the third embodiment, each of the openings 4552 and 4562 of the light shielding plates 455 and 456 is assumed to become smaller toward the center of the second small lens in the second lens array 413 in the column direction. In the fourth embodiment, Although the respective opening portions 4572 and 4582 of the light shielding plates 457 and 458 are assumed to become smaller toward the center in the column direction and the row direction of the second small lens of the second lens array 413, the present invention is not limited to this. That is, in the third and fourth embodiments, the openings 4552, 4562, 4572, 4582 formed in the respective light shielding plates 455 to 458 are formed so as to become smaller toward the illumination optical axis A. However, the present invention is not limited to this.
If the openings of the respective light shielding plates are formed in this way, only a part of the luminous flux with high illumination intensity can be irradiated to the second lens array 413 through the openings. The contrast of the projected image can be improved while reducing the light flux incident on the array 413.

In each of the embodiments, the rotation shafts 4511 to 4581 of the light shielding plates 451 to 458 are set along the direction orthogonal to the longitudinal direction of the polarization separation layer 4711 of the polarization conversion device 414, and the light shielding plates 451 to 458 are arranged. The end on the side close to the illumination optical axis A moves in the vertical direction when viewed from the direction along the illumination optical axis A, but the present invention is not limited to this. That is, the rotation shafts 4511 to 4581 of the respective light shielding plates 451 to 458 are set along the longitudinal direction of the polarization separation layer 4711, and the rotation direction is in the left-right direction when viewed from the direction along the illumination optical axis A. You may comprise so that it may rotate.
Note that an opening of the light shielding plate is formed along the column direction of the light source image formed on the second lens array 413 (longitudinal direction of the polarization separation layer 4711), and viewed from the direction along the illumination optical axis A, When the rotation axis is set in a direction substantially orthogonal to the direction in which the opening is formed, it is possible to prevent the light source image from being abruptly blocked by the light shielding plate. Therefore, the light attenuation rate of the light beam incident on the second lens array 413 can be made uniform, and the light attenuation rate can be finely adjusted.

In each of the above embodiments, the configuration in which the optical unit 4 has a substantially L shape in plan view has been described. However, the configuration is not limited thereto, and for example, a configuration having a substantially U shape in plan view may be employed.
In each of the above embodiments, the transmissive liquid crystal panel 441 having a different light beam incident surface and light beam emission surface is used. However, a reflection type liquid crystal panel having the same light incident surface and light emission surface is used. Also good.
Further, in each of the above embodiments, only the example of the projector 1 using the three liquid crystal panels 441 (441R, 441G, 441B) has been described. However, the projector is a projector using less than three or four or more liquid crystal panels. Is also applicable.

  In each of the above embodiments, the projector 1 provided with a liquid crystal panel as an optical modulation device has been exemplified. However, any other optical modulation device can be used as long as it modulates incident light according to image information to form an optical image. Good. For example, the present invention can also be applied to a projector using an optical modulation element other than a liquid crystal layer, such as a device using a micromirror. In this case, the polarizing plates on the light incident side and the light emitting side can be omitted.

  In each of the above embodiments, only an example of a front type projector that projects an image from the direction of observing the screen is given. However, the present invention is a rear type projector that projects an image from the side opposite to the direction of observing the screen. It is also applicable to.

  INDUSTRIAL APPLICABILITY The present invention can be used in a projector that forms an optical image by modulating a light beam emitted from a light source according to image information, and can be suitably used in both a front type projector and a rear type projector.

1 is a schematic diagram showing a schematic configuration of a projector according to a first embodiment of the invention. The disassembled perspective view of the polarization conversion element in the embodiment. The schematic diagram which shows the structure of the polarization conversion element in the said embodiment. The arrangement | positioning figure which looked at the integrator illumination optical system in the said embodiment from upper direction. The layout which looked at the integrator illumination optical system in the said embodiment from the horizontal direction. The schematic diagram which looked at the light-shielding plate in the said embodiment from the optical axis direction. The graph which shows the illumination intensity of the incident light beam to the 2nd lens array with respect to the rotation angle of the light-shielding plate in the said embodiment. The graph which shows the illumination intensity ratio of the projection image at the time of the full open of the light-shielding plate in the said embodiment, and the obstruction | occlusion. The schematic diagram which looked at the light-shielding plate which concerns on 2nd Embodiment of this invention from the optical axis direction. The graph which shows the illumination intensity of the incident light beam to the 2nd lens array with respect to the rotation angle of the light-shielding plate in the said embodiment. The graph which shows the illumination intensity ratio of the projection image at the time of the full open of the light-shielding plate in the said embodiment, and the obstruction | occlusion. The schematic diagram which looked at the light-shielding plate which concerns on 3rd Embodiment of this invention from the optical axis direction. The graph which shows the illumination intensity of the incident light beam to the 2nd lens array with respect to the rotation angle of the light-shielding plate in the said embodiment. The graph which shows the illumination intensity ratio of the projection image at the time of the full open of the light-shielding plate in the said embodiment, and the obstruction | occlusion. The schematic diagram which looked at the light-shielding plate which concerns on 4th Embodiment of this invention from the optical axis direction. The graph which shows the illumination intensity of the incident light beam to the 2nd lens array with respect to the rotation angle of the light-shielding plate in the said embodiment. The graph which shows the illumination intensity ratio of the projection image at the time of the full open of the light-shielding plate in the said embodiment, and the obstruction | occlusion.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projector, 3 ... Projection lens (projection optical system), 41 ... Illumination optical system (integrator illumination optical system), 44 ... Electro-optical device (optical image formation system), 45 ... Dimming device (aperture mechanism), 412 ... First lens array, 413, second lens array, 414, polarization conversion device (polarization conversion element), 415, superimposing lens, 416, light source lamp (light source), 441 (441R, 441G, 441B), liquid crystal panel (light modulation) Device), 451, 452, 453, 454, 455, 456, 457, 458 ... light shielding plate (light shielding member), 472 ... phase difference plate, 4511, 4521, 4531, 4541, 4551, 4561, 4571, 4581 ... rotation Shaft, 4512, 4522, 4532, 4542, 4552, 4562, 4572, 4582... Opening, 4711. 2 ... reflective layer.

Claims (8)

An illumination optical system that emits an illumination light beam, an optical image forming system that includes an optical modulation device that forms an optical image by modulating the illumination light beam emitted from the illumination optical system according to image information, and the formed optical image A projection optical system for enlarging and projecting,
The illumination optical system includes:
A light source;
A first lens array having a plurality of first small lenses for dividing an illumination light beam emitted from the light source into a plurality of partial light beams;
A second lens array having a plurality of second small lenses corresponding to the plurality of partial light beams divided by the first lens array;
A superimposing lens that superimposes the plurality of partial light beams together with the second lens array on an image forming region of the light modulation device;
An aperture mechanism that is interposed between the first lens array and the second lens array and partially blocks the illumination light beam emitted from the first lens array;
The diaphragm mechanism includes a light shielding member that rotates to adjust a light reduction amount of the illumination light beam,
The projector, wherein the light shielding member includes an opening that transmits a part of light for each partial light beam in a state where the light shielding member is rotated until the illumination light beam is most dimmed. The projector according to claim 1, wherein
The light source includes an arc tube having a light emitting unit on a central axis of the illumination light beam, and a reflecting mirror that reflects light emitted from the arc tube in a predetermined direction,
The aperture mechanism includes a pair of the light shielding members each having the opening.
The projector according to claim 1, wherein the pair of light shielding members are arranged at substantially symmetrical positions around a central axis of an illumination light beam emitted from the first lens array. In the projector according to claim 1 or 2,
The illumination optical system includes a polarization conversion element that converts a plurality of partial light beams divided by the first lens array into substantially one type of linearly polarized light,
The polarization conversion element includes a polarization separation layer, a reflection layer, and a retardation plate arranged corresponding to any one of the polarization separation layer and the reflection layer,
The polarization separation layer and the reflective layer have a longitudinal direction in a direction matching each other, and are alternately arranged in a plurality of rows in a direction substantially orthogonal to the longitudinal direction,
The rotating shaft of the light shielding member is disposed along a direction substantially orthogonal to the longitudinal direction of the polarization separation layer. The projector according to claim 3, wherein
A plurality of second small lenses of the second lens array are arranged along a longitudinal direction of the polarization separation layer;
The projector is characterized in that the opening is formed in a slit shape according to the arrangement of the second small lenses. The projector according to claim 4, wherein
The projector, wherein the slit-shaped opening is formed along a direction substantially orthogonal to the axial direction of the rotation shaft, and a side opposite to the rotation shaft is cut away. In the projector according to claim 4 or 5,
The width of the slit-shaped opening is formed so as to become narrower toward the center of the light shielding member in the longitudinal direction of the polarization separation layer. The projector according to claim 3, wherein
The projector is characterized in that a plurality of the openings are formed along the longitudinal direction of the polarization separation layer. The projector according to claim 7, wherein
The plurality of openings are formed so as to become smaller toward the center of the light shielding member in at least one of a longitudinal direction of the polarization separation layer and a direction substantially orthogonal to the longitudinal direction. Projector.

Images