JP2006317888A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector in which light use efficiency is not remarkably deteriorated even when smoothly good moving image display is obtained. <P>SOLUTION: Each small lens 122 of a first lens array 120 makes an illumination light flux an illumination light flux having a cross sectional shape so as to illuminate the whole image formation region in a lateral direction in the image formation region of liquid crystal device and so as to illuminate a part of the image formation region in a vertical direction and has the cross sectional shape compressed in the vertical direction. The projector further comprises a rotary prism 770 for scanning the illumination light flux along a y-axis direction on the image formation region synchronizing to a screen writing frequency of the liquid crystal device between a lighting system and the liquid crystal device. The projector is characterized in that a set of polarizing separation prisms having a polarizing separation face and a reflection face are arranged in four rows and the polarizing separation face in the first and four polarizing separation prisms out of the polarizing separation prisms are constituted to reflect the illumination light flux concerning a second polarizing component in a direction approaching an illumination optical axis 100ax. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projector.

FIG. 13 is a diagram for explaining a conventional projector. FIG. 13A is a diagram showing an optical system of a conventional projector, and FIGS. 13B and 13C are diagrams for explaining the problems of such a conventional projector.
In the projector 900A, since the liquid crystal devices 400R, 400G, and 400B used as the electro-optic modulation device are hold type display devices having luminance characteristics as shown in FIG. 13B, they are shown in FIG. Unlike the case of the CRT which is an impulse type display device having such luminance characteristics, there is a problem that a smooth moving image display cannot be obtained due to a so-called tailing phenomenon. (Refer nonpatent literature 1.).

FIG. 14 is a diagram for explaining another conventional projector. FIG. 14A is a diagram showing an optical system of another conventional projector, and FIGS. 14B and 14C are diagrams for showing an optical shutter used in such another conventional projector. It is.
In the projector 900B, as shown in FIG. 14A, optical shutters 420R, 420G, and 420B are disposed on the light incident side of the liquid crystal devices 400R, 400G, and 400B, and light is intermittently blocked by these optical shutters. This solves the problem described above. That is, the so-called tailing phenomenon is alleviated so that a smooth and high-quality moving image display can be obtained (for example, see Patent Document 1).
"Image quality of video display on hold type display" (Technical Report of IEICE, EID99-10, pages 55-60 (1999-06)) JP 2002-148712 A (FIGS. 1 to 7)

  However, in such other conventional projectors, there is a problem in that the light use efficiency is significantly reduced because light is intermittently blocked by the optical shutter.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a projector in which the light use efficiency is not significantly reduced even when a smooth and high-quality moving image display is obtained. And

  The projector according to the present invention includes a light source device that emits an illumination light beam toward the illuminated region, a first lens array that includes a plurality of small lenses for dividing the illumination light beam emitted from the light source device into a plurality of partial light beams, A second lens array having a plurality of small lenses corresponding to the plurality of small lenses of the first lens array, and polarized light for converting unpolarized light contained in an illumination light beam emitted from the second lens array into polarized light An illumination device having a conversion element and a superimposing lens for superimposing each partial light beam emitted from the polarization conversion device in an illuminated area, and an electro-optic that modulates the illumination light beam emitted from the illumination device according to image information A modulation device; and a projection optical system that projects the illumination light beam modulated by the electro-optic modulation device. Each small lens in the first lens array includes the illumination lens. The illumination light beam emitted from the apparatus illuminates the entire image forming area in one of the vertical and horizontal directions in the image forming area of the electro-optic modulator, and a part of the image forming area in the other direction. A plane shape compressed in the other direction so as to obtain an illumination light beam having such a cross-sectional shape, and between the illumination device and the electro-optic modulation device, the screen writing frequency of the electro-optic modulation device. A projector further comprising a scanning unit that synchronously scans the illumination light beam along the other direction on the image forming region, wherein the light source device emits an illumination light beam that spreads toward the illuminated region, The plurality of small lenses in the first lens array are arranged along the one direction and the other direction, and the polarization conversion element converts the illumination light beam into the first direction. A polarization separation element that separates the illumination light beam related to the light component and the illumination light beam related to the second polarization component, and the illumination light beam related to the first polarization component and the second polarization component separated by the polarization separation element A phase difference plate that converts one of the illumination light fluxes into the other, and the polarization separation element transmits the illumination light flux according to the first polarization component of the two polarization components included in the illumination light flux as it is. And a plurality of polarization separation surfaces for reflecting the illumination light flux related to the second polarization component in a direction perpendicular to the illumination optical axis, and a reflection surface for reflecting the second polarization component in a direction parallel to the illumination optical axis. The polarization separation prisms are arranged along the one direction, and the polarization separation surfaces of the polarization separation prisms at both ends in one direction of the polarization separation element among the plurality of polarization separation prisms are , The illumination light flux related to the second polarization component is reflected in a direction approaching the illumination optical axis.

  Therefore, according to the projector of the present invention, the entire image forming area is illuminated in one of the vertical and horizontal directions in the image forming area of the electro-optic modulation device, and a part of the image forming area is illuminated in the other direction. An illumination light beam having such a cross-sectional shape (that is, a cross-sectional shape compressed in the other direction) can be scanned along the other direction on the image forming region in synchronization with the screen writing frequency of the electro-optic modulator. Therefore, in the image forming area of the electro-optic modulation device, the light irradiation area and the light non-irradiation area are sequentially scrolled alternately. As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.

  According to the projector of the present invention, as described above, the illumination light beam having a cross-sectional shape compressed in the other direction is used as the first lens array using a lens array in which the planar shape of each small lens is compressed in the other direction. Unlike the case of using an optical shutter, the illumination light beam emitted from the light source device can be led to the image forming area of the electro-optic modulation device without waste, and the light utilization efficiency is greatly increased. It will not drop.

  For this reason, the projector of the present invention is a projector in which the light use efficiency is not significantly reduced even when smooth and high-quality moving image display is obtained, and the object of the present invention is achieved.

  According to the projector of the present invention, since the small lenses in the first lens array are arranged along one direction and the other direction, the light intensity distribution in the illuminated area of the electro-optic modulation device can be made uniform to some extent. Can do.

  Further, according to the projector of the present invention, the polarization separation surfaces of the polarization separation prisms at both ends in one direction of the polarization separation element are configured to reflect the illumination light beam related to the second polarization component in a direction approaching the illumination optical axis. ing. That is, one direction of the polarization separation element compared to the case where the polarization separation surfaces of the polarization separation prisms at both ends in one direction of the polarization separation element reflect the illumination light beam related to the second polarization component in the direction away from the illumination optical axis. The partial light beams incident on the polarization separation prisms at both ends of the light beam are located away from the illumination optical axis. For this reason, the first lens array that divides the illumination light beam emitted from the light source device toward the illuminated region into a plurality of partial light beams and makes the partial light beam incident on the polarization separation surface at a position further away from the illumination optical axis. Since it is not necessary to give the partial light beam a refractive power directed toward the illumination optical axis, the small lens of the first lens array that emits the partial light beam incident on the polarization separation prisms at both ends in one direction of the polarization separation element is enlarged. Eliminates the need for eccentricity. As a result, since the lens thickness of the first lens array can be reduced, the weight of the first lens array and thus the projector can be reduced. In addition, since it is possible to reduce the lens thickness of the first lens array, it is possible to shorten the cooling time when the first lens array is manufactured using press working, and to shorten the manufacturing time. There is also an effect that the manufacturing cost can be reduced.

  According to the projector of the present invention, the illumination light beam can be converted into polarized light having one polarization axis by the action of the polarization conversion element. This is suitable when an electro-optic modulation device that uses light is used.

  As the electro-optic modulation device, the planar shape of the image forming area is “vertical dimension: horizontal dimension = 3: 4 rectangular shape” and “vertical dimension: horizontal dimension = 9: 16 rectangular shape” are widely used. Therefore, as the planar shape of each small lens of the first lens array in the projector of the present invention, for example, “vertical dimension: horizontal dimension = 3: 8 rectangular shape”, “vertical dimension: horizontal dimension = 9: 32 rectangles "," vertical dimension: horizontal dimension = 1: 4 rectangle ", and the like can be preferably used.

  In the projector according to the aspect of the invention, the plurality of small lenses of the first lens array may be arranged in four rows along the one direction, and the plurality of small lenses of the second lens array. The lenses are arranged in four rows along the one direction along the other direction, and the plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array. The polarization separation surfaces of the first and fourth polarization separation prisms of the plurality of polarization separation prisms reflect the illumination light flux related to the second polarization component in a direction approaching the illumination optical axis. The polarization separation surfaces of the polarization separation prisms in the second row and the third row are configured to reflect the illumination light beam related to the second polarization component in a direction away from the illumination optical axis. Masui.

  With this configuration, the partial light flux that passes through the first and fourth small lenses in the second lens array and the partial light flux that passes through the second and third small lenses in the second lens array. Are greatly separated from each other, so that the distance between the first lens in the second lens array and the second lens in the second lens array and the distance between the third lens in the second lens array and the fourth lens in the second lens array are increased. It becomes possible to separate. For this reason, the lens function in the part between them can be made unnecessary. In addition, since the small lenses in the first lens array are arranged in four rows along one direction, the size of the small lenses can be made a certain size or more. For this reason, the length of the side along the other direction of the small lens in the first lens array is not extremely shortened. As a result, the partial light beams emitted from the respective small lenses of the first lens array can be satisfactorily swallowed by the corresponding second lens array, and good light utilization efficiency can be obtained.

  In the projector according to the aspect of the invention, the plurality of small lenses of the first lens array may be arranged in four rows along the one direction, and the plurality of small lenses of the second lens array. The lenses are arranged in four rows along the one direction along the other direction, and the plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array. And between the small lens in the first row and the small lens in the second row and between the small lens in the third row and the small lens in the fourth row of the small lenses of the second lens array, A concave surface portion is preferably provided.

  In the projector of the present invention, as described above, between the first row of small lenses and the second row of small lenses and between the third row of small lenses and the fourth row of small lenses in the second lens array. Can be separated greatly. For this reason, the second lens array, and thus the projector, can be reduced in weight by providing a concave surface portion in this largely separated portion. In addition, by providing a concave surface portion in this largely separated portion, the cooling time when manufacturing the second lens array can be shortened, the manufacturing time can be shortened and the manufacturing cost can be reduced. Can do.

  In the projector according to the aspect of the invention, the plurality of small lenses of the first lens array may be arranged in four rows along the one direction, and the plurality of small lenses of the second lens array. The lenses are arranged in four rows along the one direction along the other direction, and the plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array. Between the small lenses in the first row and the small lenses in the second row and between the small lenses in the third row and the small lenses in the fourth row among the small lenses in the second lens array. It is also preferable that it is connected to.

  In the projector of the present invention, as described above, between the first row of small lenses and the second row of small lenses and between the third row of small lenses and the fourth row of small lenses in the second lens array. Therefore, it is not necessary to make this portion an accurate lens. Therefore, by smoothly connecting these portions, it is possible to reduce the manufacturing cost of the mold when manufacturing the second lens array by press working.

  In the projector according to the aspect of the invention, the plurality of small lenses of the first lens array may be arranged in four rows along the one direction, and the plurality of small lenses of the second lens array. The lenses are arranged in four rows along the one direction along the other direction, and the plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array. The polarization separation surfaces of the polarization separation prisms in the first and fourth rows of the polarization separation prisms reflect the illumination light beam related to the second polarization component in a direction approaching the illumination optical axis. Preferably, the polarization separation surfaces of the polarization separation prisms in the second row and the third row are configured to reflect the illumination light flux related to the second polarization component in a direction approaching the illumination optical axis.

  Also with this configuration, as described above, the first lens array corresponding to the partial light beams passing through the first lens and the fourth lens in the second lens array is arranged on the illumination optical axis as in the prior art. It is no longer necessary to give the directed refractive power to the partial light beam, and also in the first lens array corresponding to the partial light beam passing through the second lens and the third lens in the second lens array, illumination is performed as in the related art. It is no longer necessary to give the partial luminous flux a refractive power directed toward the optical axis. Accordingly, it is not necessary to decenter the small lenses in the first column to the fourth column in the first lens array that divides the illumination light beam that spreads toward the illuminated area emitted from the light source device. As a result, since the lens thickness of the first lens array can be reduced, the weight of the first lens array and thus the projector can be reduced. In addition, since it is possible to reduce the lens thickness of the first lens array, it is possible to shorten the cooling time when the first lens array is manufactured using press working, and to shorten the manufacturing time. There is also an effect that the manufacturing cost can be reduced.

  In the projector according to the aspect of the invention, it is preferable that the optical axis of each small lens in the first lens array exists within the width of each small lens in the one direction.

  With this configuration, since the amount of decentering of the small lenses of the first lens array is small, the lens thickness of the first lens array can be reduced. In addition, the partial light beams that pass through the first lens and the fourth lens in the second lens array are located farther from the illumination optical axis than in the past, and the polarization separation surfaces in the first and fourth polarization separation prisms. Well guided.

  In the projector according to the aspect of the invention, it is preferable that each small lens in the first lens array has a larger amount of decentering in the other direction as the small lens is farther from the illumination optical axis in the row along the other direction.

  With this configuration, the separation of the arc image along the other direction in the second lens array is improved, and the light utilization efficiency is improved.

  In the projector according to the aspect of the invention, in the first lens array, the plurality of small lenses may be arranged in four rows along the other direction, and the plurality of polarization separation prisms may include the first lens array. The lens elements are arranged in four rows corresponding to the rows of the plurality of small lenses in one lens array, and each small lens in the first lens array has an eccentric amount in the other direction of the first lens and the fourth lens in the other direction. In comparison, it is preferable that the decentering amount of the small lens in the other direction of the second row and the third row is large.

  Since the partial light beams from the second and third rows of the first lens array are not well separated from each other in the arc image in the vicinity of the second lens array, it is not easy to improve the light utilization efficiency. Therefore, as described above, by increasing the decentering amount of the small lens in the other direction of the second row and the third row as compared with the decentering amount of the small lens in the other direction of the first row and the fourth row, The separation of the arc image becomes better and it becomes easy to improve the light utilization efficiency.

  In the projector according to the aspect of the invention, it is preferable that the plurality of small lenses in the first lens array are arranged in 8 to 10 rows along the other direction.

  With this configuration, the length of the side along the other direction of the small lens in the first lens array is not extremely shortened, so that the partial light flux emitted from each small lens of the first lens array , The corresponding second lens array can be satisfactorily swallowed, and good light utilization efficiency can be obtained.

  In the projector according to the aspect of the invention, the light source device includes an arc tube having a light emitting unit, an elliptical reflector that reflects light emitted from the light emitting unit, and light reflected by the elliptical reflector toward an illuminated area. A concave lens for converting the illumination light beam to spread; and an auxiliary mirror for reflecting the light emitted from the light emitting unit toward the illuminated region to the light emitting unit, wherein the auxiliary mirror is an illumination on the light incident surface of the first lens array. It is preferable to have a shape in which a part of the concave concave surface is removed so that the length along the other direction in the cross section of the light beam is shorter than the length along the one direction.

  By comprising in this way, the cross-sectional shape of the illumination light beam reflected by an ellipsoidal reflector becomes a shape where the other direction is smaller than one direction. Accordingly, it is possible to shorten the dimension along the other direction of each optical element in the subsequent stage including the concave lens, the first lens array, the second lens array, the polarization conversion element, and the superimposing lens, thereby reducing the size of the entire apparatus. be able to. Moreover, the cross-sectional shape of the illumination light beam reflected by the ellipsoidal reflector is compatible with the cross-sectional shape of each small lens in the first lens array having a shape compressed in the other direction.

  In the projector according to the aspect of the invention, it is assumed that the ellipsoidal reflector has a reflective concave surface required for reflecting the light passing therethrough when it is assumed that the light emitted from the light emitting unit passes without being reflected by the auxiliary mirror. It is preferable that the portion has a deleted shape.

  By comprising in this way, since the dimension along the other direction of an ellipsoidal reflector can be shortened, the further size reduction of the whole apparatus can be achieved.

  In the projector according to the aspect of the invention, the ratio of the length along the other direction to the length along the one direction in the cross section of the illumination light beam on the light incident surface of the first lens array is 30% to 80%. It is preferable that

  When this ratio is less than 30%, it is not easy to maintain the light use efficiency of the illumination light beam reflected by the ellipsoidal reflector, and the number of small lenses in the first lens array can be secured. It becomes impossible to make the light intensity distribution on the electro-optic modulator uniform. On the other hand, when this ratio exceeds 80%, the effect that the apparatus can be reduced in size becomes small. From these viewpoints, the ratio is more preferably 40% to 70%.

  In the projector according to the aspect of the invention, the first lens array has a light incident surface closer to the ellipsoidal reflector than the second focal point of the ellipsoidal reflector, and illumination emitted from the light source device on the light incident surface. It is preferable that the light beam is disposed at a position where the light amount of the light beam is distributed throughout.

  With this configuration, the amount of illumination light beam emitted from the light source device is distributed over the entire light incident surface of the first lens array. Therefore, even if the first lens array having a low lens density is arranged by arranging the small lenses in four rows, the in-plane light intensity distribution characteristic on the illuminated area of the electro-optic modulation device is not lowered, and the first lens array is reduced. Simplification of manufacturing process and cost reduction in one lens array can be achieved.

  In this case, it is preferable to dispose the first lens array at a position where there is no extremely small region of incident light intensity (shadow region of the arc tube) at the center of the light incident surface of the first lens array. With this configuration, the amount of illumination light beam emitted from the light source device is distributed over the entire light incident area of the first lens array.

  In the projector according to the aspect of the invention, a color separation optical system for separating an illumination light beam emitted from the illumination device into a plurality of color lights may be further provided between the illumination device and the electro-optic modulation device. As a modulation device, a plurality of electro-optic modulation devices that modulate a plurality of color lights emitted from the color separation optical system according to image information corresponding to each color light, and color lights modulated by the plurality of electro-optic modulation devices And a dichroic prism for synthesizing the two.

  With this configuration, a projector in which the light use efficiency is not significantly reduced even when smooth and high-quality moving image display can be obtained is a full-color projector with excellent image quality (for example, a three-plate type). Will be able to.

  In the projector according to the aspect of the invention, the scanning unit may be disposed between the illumination device and the color separation optical system at a position substantially conjugate with the electro-optic modulation device, and may have a rotation axis perpendicular to the illumination optical axis. The rotating prism includes a rotating prism, and the rotating prism sequentially scrolls the light irradiation region and the light non-irradiation region on the electro-optic modulation device in synchronization with the screen writing frequency of the electro-optic modulation device. It is preferable that it is comprised.

  With this configuration, it is possible to realize a smooth scroll operation of the light irradiation region and the light non-irradiation region in the image forming region of each electro-optic modulation device in the full color projector.

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

Embodiment 1
FIG. 1 is a diagram for explaining the projector according to the first embodiment. FIG. 1A is a view of the optical system of the projector according to the first embodiment as viewed from above, FIG. 1B is a view of the optical system as viewed from the side, and FIG. It is a figure which shows typically the locus | trajectory of a light ray.
In the following description, the three directions orthogonal to each other are defined as the z-axis direction (illumination optical axis 100ax direction in FIG. 1A) and the x-axis direction (parallel to the paper surface in FIG. And a direction perpendicular to the paper surface in FIG. 1A and perpendicular to the z-axis.

  As shown in FIGS. 1A and 1B, the projector 1000 according to the first embodiment separates the illumination device 100 and the illumination light flux from the illumination device 100 into three color lights of red, green, and blue. Color separation optical system 200, three liquid crystal devices 400R, 400G, and 400B as electro-optic modulation devices that modulate each of the three color lights separated by color separation optical system 200 according to image information, and these three liquid crystals The projector includes a cross dichroic prism 500 that combines color lights modulated by the devices 400R, 400G, and 400B, and a projection optical system 600 that projects the light combined by the cross dichroic prism 500 onto a projection surface such as a screen SCR. .

  As shown in FIGS. 1A and 1B, the illuminating device 100 emits an illumination light beam that spreads toward the illuminated area, and a plurality of illumination light beams emitted from the light source device 110. A first lens array 120 having a plurality of small lenses 122 (see FIG. 3) for splitting into partial light beams, and a plurality of small lenses 132 (not shown) corresponding to the plurality of small lenses 122 of the first lens array 120. A second lens array 130, a polarization conversion element 140 for converting the illumination light beam into substantially one type of linearly polarized light, and a superimposing lens 150 for superimposing each partial light beam from the polarization conversion element 140 in the illuminated region. Have.

As shown in FIGS. 1A and 1B, the light source device 110 includes an ellipsoidal reflector 114, an arc tube 112 having a light emission center near the first focal point of the ellipsoidal reflector 114, and the ellipsoidal reflector 114. And a concave lens 118 that converts the focused light reflected by the light into divergent light. The arc tube 112 is provided with an auxiliary mirror 116 as a reflecting means for reflecting the light emitted from the arc tube 112 toward the illuminated area toward the ellipsoidal reflector 114.
The light source device 110 emits an illumination light beam having the illumination optical axis 100ax as a central axis.
The first lens array 120 includes a plurality of small lenses 122 arranged in a plane perpendicular to the illumination optical axis 100ax, and the illumination light beam emitted from the light source device 110 is converted into a plurality of partial light beams according to the plurality of small lenses 122. Divide into
The second lens array 130 includes a plurality of small lenses 132 arranged in a plane perpendicular to the illumination optical axis 100ax. The small lenses 132 respectively correspond to the partial light beams divided by the first lens array 120, and each of the partial light beams is condensed so as to enter the polarization separation surface of the polarization conversion element 140.
The polarization conversion element 140 converts the partial light beam emitted from the second lens array 130 into substantially one type of linearly polarized light and emits it. For this reason, since the illumination light beam can be converted into polarized light having one polarization axis by the action of the polarization conversion element 140, like the liquid crystal devices 400R, 400G, and 400B of the projector 1000 according to the first embodiment. Thus, the illumination light beam is suitable when an electro-optic modulation device using polarized light such as a liquid crystal device is used as the electro-optic modulation device.
The superimposing lens 150 is an optical element that superimposes a plurality of partial light beams emitted from the polarization conversion element 140 in the vicinity of an in-plane perpendicular to the illumination optical axis 100ax including the rotation axis 772 of the rotating prism 770.
The rotation prism 770 rotates about the rotation axis 772 to move the passing position of the incident illumination light beam in the plane perpendicular to the illumination optical axis 100ax near the rotation axis 772, and thereby the liquid crystal devices 400R and 400G. , 400B, the illumination area and the non-illumination area are scrolled.
Details of the ellipsoidal reflector 114 and the auxiliary mirror 116, the first lens array 120, the polarization conversion element 140, and the rotating prism 770 of the light source device 110 will be described later.

The illumination light beam emitted from the rotating prism 770 enters the color separation optical system 200.
As the color separation optical system 200, as shown in FIG. 1A, an equal optical path optical system having the same optical path length from the illumination device 100 to the liquid crystal devices 400R, 400G, and 400B is used.
As shown in FIG. 1A, the color separation optical system 200 includes dichroic mirrors 720 and 724, reflection mirrors 722, 726, 728, 730, and 732, relay lenses 752, 736, 756, a field lens 758, 760, 762.
The relay lenses 752, 736, and 756 are optical elements that cause the illumination light beam emitted from the rotating prism 770 to form an image on the image forming areas of the liquid crystal devices 400R, 400G, and 400B. Field lenses 758, 760, and 762 are provided to convert each partial light beam into a light beam substantially parallel to each principal ray.
The dichroic mirror 720 transmits the red light component and the green light component of the light emitted from the rotating prism 770 and reflects the blue light component. The blue light component reflected by the dichroic mirror 720 is reflected by the reflection mirrors 728, 730, and 732, and reaches the blue light liquid crystal device 400B. On the other hand, the red light component and the green light component transmitted through the dichroic mirror 720 are reflected by the reflection mirror 722 and enter the dichroic mirror 724. In the dichroic mirror 724, the red light component is transmitted and the green light component is reflected. The red light component transmitted by the dichroic mirror 724 is reflected by the reflection mirror 726 and reaches the liquid crystal device 400R for red light. The green light component reflected by the dichroic mirror 724 is further reflected by the reflection mirror 728 and reaches the green light liquid crystal device 400G.

The liquid crystal devices 400R, 400G, and 400B modulate an illumination light beam according to image information to form an image for each color light, and are illumination targets of the illumination device 100. Although not shown, incident side polarizing plates are interposed between the field lenses 758, 760, and 762 and the liquid crystal devices 400R, 400G, and 400B, respectively, and are crossed with the liquid crystal devices 400R, 400G, and 400B. Between the dichroic prism 500, an exit side polarizing plate is interposed. The incident-side polarizing plate, the liquid crystal devices 400R, 400G, and 400B and the exit-side polarizing plate modulate light of each color light incident thereon.
The liquid crystal devices 400R, 400G, and 400B are a pair of transparent glass substrates in which a liquid crystal that is an electro-optical material is hermetically sealed. For example, incident side polarization is performed according to a given image signal using a polysilicon TFT as a switching element. The polarization direction of one type of linearly polarized light emitted from the plate is modulated.
As the liquid crystal devices 400R, 400G, and 400B, a wide vision liquid crystal device having a planar shape of “longitudinal dimension along the y-axis direction: lateral dimension along the x-axis direction = 9: 16 rectangle” is used. .

The cross dichroic prism 500 is an optical element that forms a color image by synthesizing optical images modulated for the respective color lights emitted from the emission-side polarizing plate. The cross dichroic prism 500 has a substantially square shape in plan view in which four right-angle prisms are bonded together, and a dielectric multilayer film is formed on a substantially X-shaped interface in which the right-angle prisms are bonded together. The dielectric multilayer film formed at one of the substantially X-shaped interfaces reflects red light, and the dielectric multilayer film formed at the other interface reflects blue light. By these dielectric multilayer films, the red light and the blue light are bent and aligned with the traveling direction of the green light, so that the three color lights are synthesized.
The color image emitted from the cross dichroic prism 500 is enlarged and projected by the projection optical system 600 to form a large screen image on the screen SCR.
Hereinafter, the ellipsoidal reflector 114 and the auxiliary mirror 116, the first lens array 120, the polarization conversion element 140, and the rotating prism 770 in the projector 1000 according to the first embodiment will be described in detail.

1. Ellipsoidal Reflector and Auxiliary Mirror FIG. 2 is a diagram for explaining the shapes of the ellipsoidal reflector 114 and the auxiliary mirror 116 in the first embodiment. 2 (a) is a plan view, FIG. 2 (b) is a side view, FIG. 2 (c) is a view seen from the illuminated region side, and FIG. 2 (d) is a perspective view.
The arc tube 112 includes a light emitting part having a light emission center and a pair of sealing parts extending from both ends of the light emitting part.
The ellipsoidal reflector 114 has a reflecting concave surface that is a spheroidal surface having a first focal point and a second focal point. The ellipsoidal reflector 114 is attached to one sealing portion of the arc tube 112 so that the first focal point of the ellipsoidal reflector 114 and the emission center of the arc tube 112 substantially coincide. The ellipsoidal reflector 114 reflects the light emitted from the light emitting portion of the arc tube 112 and focuses it toward the second focal point of the ellipsoidal reflector 114.
The auxiliary mirror 116 has a reflective concave surface having a spherical shape. The auxiliary mirror 116 is attached to the other sealing portion of the arc tube 112 so that the center of curvature of the auxiliary mirror 116 and the emission center of the arc tube 112 substantially coincide. The auxiliary mirror 116 reflects the light emitted from the light emitting portion of the arc tube 112 toward the illuminated area (the side opposite to the ellipsoidal reflector 114) to the ellipsoidal reflector 114. In other words, the auxiliary mirror 116 reflects the light emitted from the light emitting portion of the arc tube 112 toward the illuminated area to the light emitting portion of the arc tube 112, so that the light reflected by the auxiliary mirror 116 passes through the arc tube 112. The ellipsoidal reflector 114 is focused on the second focal point of the ellipsoidal reflector 114.

In the projector 1000 according to the first embodiment, the auxiliary mirror 116 has a length along the y-axis direction in the section of the illumination light beam on the light incident surface of the first lens array 120 that is longer than the length along the x-axis direction. A part of the reflective concave surface is deleted so as to be shorter.
That is, “the longitudinal dimension along the y-axis direction: the rectangular dimension along the x-axis direction = 1: 4 rectangle” the small lens 122 is transverse in a plane perpendicular to the illumination optical axis 100ax that is the central axis of the illumination light beam. When arranged in a rectangular area such that the length in the direction: length in the longitudinal direction = 2: 1, the auxiliary mirror 116 has a longitudinal direction in the longitudinal direction. Thereby, the auxiliary mirror 116 acts to compress the illumination light beam in the vertical direction.
Therefore, the cross-sectional shape of the illumination light beam reflected by the ellipsoidal reflector 114 is smaller in the vertical direction along the y-axis direction than in the horizontal direction along the x-axis direction.
For this reason, the cross-sectional shape of the illumination light beam reflected by the ellipsoidal reflector 114 is such that the horizontal length in which the small lenses 122 are arranged in the first lens array 120: the vertical length = 2: 1. Therefore, the light emitted from the light source device 100 can be used without waste.
Further, the vertical dimension along the y-axis direction of each optical element in the subsequent stage including the concave lens 118, the first lens array 120, the second lens array 130, the polarization conversion element 140, and the superimposing lens 150 can be shortened. The entire apparatus can be reduced in size.

  In the projector 1000 according to the first embodiment, as shown in FIGS. 1 and 2, the ellipsoidal reflector 114 assists when light emitted from the light emitting unit passes without being reflected by the auxiliary mirror 116. The reflection concave surface portion required for reflecting the light passing through without being reflected by the mirror 116 is removed. In other words, when the auxiliary mirror 116 has a shape having a longitudinal direction in the longitudinal direction along the y-axis direction, the ellipsoidal reflector 114 has a shape having a longitudinal direction in the lateral direction along the x-axis direction. For this reason, since the vertical dimension along the y-axis direction of the ellipsoidal reflector 114 can be shortened, further downsizing of the entire apparatus can be achieved.

2. First Lens Array and Polarization Conversion Element First, the first lens array 120 will be described in detail with reference to FIGS.
FIG. 3A to FIG. 3C are views for explaining the structure of the first lens array in the first embodiment. 3A is a view seen from the direction along the z-axis direction, FIG. 3B is a view seen from the direction along the y-axis direction, and FIG. 3C is a view taken along the x-axis direction. It is the figure seen from the direction along.
FIGS. 4A to 4C are views for explaining the structure of the first lens array according to the comparative example of the first embodiment. 4A is a diagram viewed from a direction along the z-axis direction, FIG. 4B is a diagram viewed from a direction along the y-axis direction, and FIG. 4C is a diagram viewed from the x-axis direction. It is the figure seen from the direction along.
FIG. 5A to FIG. 5B are diagrams showing the light intensity distribution in the section of the illumination light beam by contour lines. FIG. 5A is a diagram showing the light intensity distribution of the illumination light beam on the light incident surface of the first lens array. FIG. 5B is a diagram showing the light intensity distribution of the illumination light beam on the image forming area of the liquid crystal device.
The black dots shown in FIGS. 3A and 4A indicate the optical axis of each small lens 122.

The arrangement of the plurality of small lenses 122 will be described in detail.
In order to illuminate the illumination area more uniformly, it is desirable to divide the illumination light beam from the light source device 100 into a larger number of partial light beams and superimpose them on the illumination area. However, the pitch of the light source images must be ensured so that the light source images formed by the partial light beams divided by the small lenses 122 of the first lens array 120 do not overlap on the second lens array 130, and The number of light source images is limited so that the size of the optical system after the second lens array 130 does not become too large. That is, the number of small lenses 122 is limited. If the light source images overlap, a partial light beam that does not correspond is incident on the small lens 132 of the second lens array 130 that corresponds to the partial light beam divided by the first lens array. The partial light flux that is not performed is not effectively superimposed on the illumination area.
When small lenses 122 having a planar shape of “vertical dimension along the y-axis direction: rectangular dimension along the x-axis direction = 1: 4” are arranged with the x-axis direction as a column and the y-axis direction as a row The pitch of the light source images formed by the partial light beams divided into the numbers corresponding to the small lenses 122 is narrower in the row direction than in the column direction.
As shown in FIG. 3, the first lens array 120 has a plurality of small lenses 122 arranged in 4 columns and 8 rows with the illumination optical axis 100ax interposed therebetween.
For this reason, a sufficient number of partial light beams can be secured, so that the light intensity distribution in the illuminated areas of the liquid crystal devices 400R, 400G, and 400B can be made uniform to some extent as shown in FIG. In addition, since the plurality of small lenses 122 in the first lens array 120 are arranged in four columns along the x-axis direction and eight rows along the y-axis direction, the light exits from the small lenses 122 of the first lens array 120. Therefore, the size of the small lens 122 can be ensured so that the partial light flux to be applied is satisfactorily swallowed by the corresponding second lens array 130. For this reason, good light utilization efficiency can be obtained for the light that illuminates the illumination area with respect to the light emitted from the light source device 110.
As shown in FIG. 3A, the plurality of small lenses 122 in the first lens array 120 is a plane of “vertical dimension along the y-axis direction: lateral dimension along the x-axis direction = 1: 4 rectangle”. It has a shape. For this reason, the first lens array 120 illuminates the illumination light beam emitted from the illumination device 100 along the x-axis direction in the image forming region of each of the liquid crystal devices 400R, 400G, and 400B, as shown in FIG. An illumination light beam having a cross-sectional shape that illuminates the entire image forming area in the horizontal direction and a part (about half) of the image forming area in the vertical direction along the y-axis direction can be used.

In the projector 1000 according to the first embodiment, the ratio of the length along the y-axis direction to the length along the x-axis direction is the horizontal length: vertical direction as shown in FIG. A plurality of small lenses 122 of the first lens array 120 are arranged in a region where the length = 2: 1. That is, the ratio of the length along the y-axis direction to the length along the x-axis direction of the incident surface of the first lens array 120 is 50%.
For this reason, since this ratio is 30% or more, the light use efficiency of the illumination light beam reflected by the ellipsoidal reflector 114 can be maintained, and the number of rows of the small lenses 122 in the first lens array 120 can be secured. Therefore, the light intensity distribution on the liquid crystal devices 400R, 400G, and 400B can be made uniform. Moreover, since this ratio is 80% or less, the apparatus can be miniaturized.

  In the projector 1000 according to the first embodiment, the first lens array 120 has a light incident surface closer to the ellipsoidal reflector 114 than the second focal point of the ellipsoidal reflector 114, and is emitted from the light source device 110 on the light incident surface. It is arranged at a position where the amount of illumination light flux to be distributed over the whole. For this reason, as shown in FIG. 5A, the light quantity of the illumination light beam emitted from the light source device 110 is distributed over the entire light incident surface of the first lens array 120. Therefore, even if the small lenses 122 are arranged in four rows to form the first lens array 120 having a low lens density, the in-plane light intensity distribution characteristics on the illuminated areas of the liquid crystal devices 400R, 400G, and 400B are reduced. Therefore, it is possible to simplify the manufacturing process and reduce the cost of the first lens array.

  In this case, it is preferable to arrange the first lens array 120 at a position where there is no extremely small region of incident light intensity (a shadow region of the arc tube 112) in the center of the light incident surface of the first lens array 120. . With this configuration, the amount of illumination light beam emitted from the light source device 110 on the light incident area of the first lens array 120 is distributed over the entire area.

As described above, the small lens 122 of the first lens array 120 according to the first embodiment has a planar shape of “longitudinal dimension along the y-axis direction: lateral dimension along the x-axis direction = 1: 4 rectangle”. Have. Therefore, the plurality of partial light beams emitted from the first lens array 120 are closer to the y-axis direction than the x-axis direction. Therefore, the partial light flux on the incident surface of the second lens array 130 is larger than the interval of the partial light fluxes on the exit surface of the first lens array 120 so that the partial light flux is favorably incident on the small lens 132 of the second lens array 130. Eccentric lenses are used for the small lenses 122 of the first lens array 120 so that the distance between them becomes larger. However, when a lens having a large amount of eccentricity is used for each small lens 122 of the first lens array 120, the shape of each small lens is greatly different, a large step is generated between the small lenses, or the thickness of the first lens array 120 is reduced. In addition to making the first lens array difficult to manufacture, the weight of the first lens array increases.
However, in this embodiment, since the illumination light beam that is emitted from the light source device 110 and spreads toward the illuminated region is incident on the first lens array 120, the amount of eccentricity of the small lens 122 of the first lens array 120 is reduced accordingly. Can be suppressed.
Here, by referring to the structure of the first lens array 120a in the projector according to the comparative example shown in FIG. 4, the structure of the first lens array 120 in the projector 1000 according to the first embodiment and the effect thereof will be further described.
In the projector (not shown) according to the comparative example, each small lens 122a in the first lens array 120a is in each of the first to fourth rows of small lenses 122a as shown in FIG. The amount of eccentricity in the y-axis direction is equal. On the other hand, in the projector 1000 according to the first embodiment, each small lens 122 in the first lens array 120 is, as shown in FIG. 3A, the y-axis of the first and fourth rows of small lenses 122. The amount of eccentricity of the small lens 122 in the second and third rows in the y-axis direction is larger than the amount of eccentricity in the direction. For example, in FIG. 3A, the distance from the lens center of the optical axis α2 of the small lens 122 in the second column from the left is larger than the distance from the lens center of the optical lens α1 of the small lens 122 in the second column from the left. long. This is because the illumination light beam spreading toward the illuminated area is emitted from the light source device 110, but the light near the center of the illumination light beam incident on the first lens array 120, that is, the light near the illumination optical axis 100ax is the periphery thereof. Since the angle with respect to the illumination optical axis 100ax is shallower than the first light, if the first lens array is not an eccentric lens, the partial light beams from the second and third rows of the first lens array 120 are in the vicinity of the second lens array. The arc image is not well separated. Therefore, it is not easy to improve the light use efficiency. Therefore, as described above, the decentering amount of the small lens 122 in the y-axis direction of the second row and the third row is larger than the decentering amount of the small lens 122 in the y-axis direction of the first row and the fourth row. By doing so, the separation of the arc image becomes better and it becomes easy to improve the light utilization efficiency. However, in the present embodiment, since the illumination light beam spreading toward the illuminated area is emitted from the light source device 110, the first lens array 120 is difficult to manufacture due to the eccentricity of the small lens 122 of the first lens array 120. In addition, the weight of the first lens array 120 does not increase significantly.

In the projector (not shown) according to the comparative example, as shown in FIG. 4A, the optical axes β1 and β4 of the small lenses 122a in the first and fourth rows in the first lens array 120a. Exists at a position deviating from the width of each small lens 122a itself in the x-axis direction. For example, in FIG. 4A, the optical axis β1 of the small lens 122a in the first column from the left exists in the small lens in the second column from the left. On the other hand, in the projector 1000 according to the first embodiment, as shown in FIG. 3A, the optical axes α1 to α4 of the small lenses 122 in the first lens array 120 are the small lenses 122 in the x-axis direction. It exists within its own width.
This relates to the configuration of the polarization conversion element 140 according to the first embodiment, which will be described in detail below with reference to FIGS.

FIGS. 6A and 6B are views for explaining the structure of the polarization conversion element 140 according to the first embodiment. FIG. 6A is a diagram schematically showing the locus of light rays from the first lens array 120 to the polarization conversion element 140, and FIG. 6B is an arc image in the second lens array 130 and the polarization conversion element 140. FIG.
FIGS. 7A and 7B are views for explaining the structure of the polarization conversion element 140a in the comparative example of the first embodiment. FIG. 7A is a diagram schematically showing a locus of light rays from the first lens array 120a to the polarization conversion element 140a, and FIG. 7B is an arc image in the second lens array 130a and the polarization conversion element 140a. FIG.

  As illustrated in FIG. 6A, the polarization conversion element 140 includes a polarization separation element 1411 that separates the illumination light beam into an illumination light beam according to the first polarization component and an illumination light beam according to the second polarization component, And a phase difference plate that converts one of the illumination light beam related to the second polarization component and the illumination light beam related to the second polarization component into the other. The polarization separation element 1411 includes a plurality of polarization separation prisms 1413 and 1414. The polarization separation prisms 1413 and 1414 transmit the illumination light beam related to the first polarization component of the two polarization components included in the illumination light beam as they are, and pass the illumination light beam related to the second polarization component perpendicular to the illumination optical axis 100ax. And a reflection surface 1416 that reflects the second polarization component in a direction parallel to the illumination optical axis 100ax. The plurality of polarization separation prisms 1413 and 1414 correspond to the four rows of the plurality of small lenses 122 (see FIG. 3) in the first lens array 120, and the polarization separation prism 1413 on both sides and the polarization separation prism 1414 on the middle side. A total of four are arranged.

Here, in the projector (not shown) according to the comparative example, the polarization separation surface 1415a in the polarization separation prism 1414a corresponding to the first to fourth rows of the small lenses of the second lens array 130a is shown in FIG. As shown in FIG. 6A, the illumination light flux related to the second polarization component is reflected in a direction away from the illumination optical axis 100aax, whereas the projector 1000 according to the first embodiment has a configuration shown in FIG. As shown in a), the polarization separation surface 1415 of the polarization separation prism 1413 corresponding to the first and fourth rows of the small lenses of the second lens array 130 converts the illumination light beam related to the second polarization component into the illumination optical axis 100ax. It is comprised so that it may reflect in the direction approaching.
That is, the polarization separation element 140 according to Embodiment 1 separates the illumination light beams emitted from the columns (first and fourth columns) on both ends of the second lens array 130 (first lens array 120). In the prism 1413, the polarization separation surface 1415 is located farther from the illumination optical axis 100ax than the reflection surface 1416. On the other hand, the polarization separation element 140a of the comparative example is a polarization separation prism 1414a that separates the illumination light beams emitted from the columns (first column to fourth column) on both ends of the second lens array 130a (first lens array 120a). The polarization separating surface 1415a is closer to the illumination optical axis 100aax than the reflecting surface 1416a.
As a result, the partial light beams passing through the first lens and the fourth lens in the second lens array 130 are applied to the polarization separation surface 1415 of the polarization conversion element 140 even at a position farther from the illumination optical axis 100ax than in the past. Can be incident. On the other hand, in order to make the illumination light beam emitted from the light source device, which spreads toward the illuminated region, enter the polarization separation surfaces 1415a of the polarization separation prisms 1414a at both ends of the polarization separation element, in the comparative example, the first lens array 120a causes a partial light beam. It is necessary to give a large refractive power toward the illumination optical axis 100aax. That is, in the comparative example, it is necessary to increase the amount of eccentricity of the small lens of the first lens array 120a.
For this reason, the illumination light beam corresponding to this partial light beam does not need to be subjected to the refractive power directed to the illumination optical axis 100ax by the first lens array 120 as in the prior art. It is not necessary to decenter the small lenses 122 (see FIG. 3) in the row. As a result, since the lens thickness of the first lens array 120 can be reduced, the weight of the first lens array and thus the projector can be reduced. In addition, since it is possible to reduce the lens thickness of the first lens array 120, it is possible to reduce the cooling time when the first lens array is manufactured using press working, thereby reducing the manufacturing time. In addition, the manufacturing cost can be reduced.

In the projector 1000 according to the first embodiment, as shown in FIG. 6A, the polarization separation surfaces in the polarization separation prisms in the second and third columns of the polarization separation prisms are illuminations related to the second polarization component. The light beam is configured to be reflected in a direction away from the illumination optical axis 100ax.
For this reason, the partial light flux that passes through the first and fourth small lenses in the second lens array 130 and the partial light flux that passes through the second and third small lenses in the second lens array 130 are large. The second lens array 130 is spaced apart from the first row of small lenses and the second row of small lenses and from the third row of small lenses to the fourth row of small lenses. It becomes possible. For this reason, the lens function in the part between them can be made unnecessary.

3. Rotating Prism FIGS. 8A to 8C are diagrams showing the relationship between the rotation of the rotating prism 770 and the illumination state on the liquid crystal device 400R (same for 400G and 400B). FIG. 8A is a cross-sectional view of the rotating prism 770 when viewed along the rotation axis 772. FIG. 8B is a view of the rotating prism 770 when viewed along the illumination optical axis 100ax. FIG. 8C is a diagram showing the illumination state of the illumination light beam on the image forming area of the liquid crystal device 400R (the same applies to 400G and 400B).

  As shown in FIG. 8A and FIG. 8B, an image P of the virtual center point of the illumination area where the partial light beams emitted from the first lens array 120 on the illumination optical axis 100ax are superimposed is a rotating prism 770. As the lens rotates, the state of scrolling in a direction (vertical direction) substantially perpendicular to the rotation shaft 772 around the rotation shaft 772 of the rotating prism 770 is shown. As a result, as shown in FIG. 8C, when the rotating prism 770 rotates, the light irradiation region and the light non-irradiation region are sequentially scrolled alternately in the image forming regions of the liquid crystal devices 400R, 400G, and 400B. become.

  As described above, the configuration and characteristics of the projector 1000 according to the first embodiment have been described. As described above, according to the projector 1000 according to the first embodiment, the liquid crystal devices 400R, 400G, and 400B have the vertical and horizontal directions. A cross-sectional shape that illuminates the entire image forming area in the horizontal direction along the x-axis direction and a part of the image forming area in the vertical direction along the y-axis direction (ie, compressed in the vertical direction) Since the illumination light beam having a cross-sectional shape can be scanned along the vertical direction on the image forming area in synchronization with the screen writing frequency of the liquid crystal device, the image forming areas of the liquid crystal devices 400R, 400G, and 400B In FIG. 3, the light irradiation region and the light non-irradiation region are scrolled alternately. As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.

  Further, according to the projector 1000 according to the first embodiment, the illumination light beam having the cross-sectional shape compressed in the vertical direction as described above is compressed as the first lens array 120 and the planar shape of each small lens 122 is compressed in the vertical direction. Since this is realized by using the lens array, unlike the case of using the optical shutter, the illumination light beam emitted from the light source device 110 can be guided to the image forming areas of the liquid crystal devices 400R, 400G, and 400B without waste. Thus, the light use efficiency is not greatly reduced.

  For this reason, the projector 1000 according to the first embodiment is a projector in which the light use efficiency is not significantly reduced even when smooth and high-quality moving image display is obtained.

  In the projector 1000 according to the first embodiment, the color separation optical system 200 for separating the illumination light beam emitted from the illumination device 100 into a plurality of color lights is provided between the illumination device 100 and the liquid crystal devices 400R, 400G, and 400B. In addition, a plurality of liquid crystal devices 400R, 400G, and 400B that modulate a plurality of color lights emitted from the color separation optical system 200 according to image information corresponding to each color light are provided as liquid crystal devices. For this reason, even if smooth and high-quality moving image display is obtained, a projector in which the light use efficiency is not significantly reduced can be a three-plate full-color projector with excellent image quality.

  In the projector 1000 according to the first embodiment, the antireflection film is formed on the light transmission surface of the rotating prism 770. For this reason, since the light transmittance in the rotating prism 770 is improved, a decrease in light utilization efficiency can be minimized, and the stray light level is reduced and the contrast is improved.

[Embodiment 2]
FIG. 9 is a view for explaining the structure of the second lens array in the second embodiment. FIG. 9A is a diagram schematically showing a locus of light rays from the first lens array to the polarization conversion element, and FIG. 9B is a diagram showing an arc image in the second lens array and the polarization conversion element. is there. In FIG. 9, the same members as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

A projector 1000B (not shown) according to the second embodiment is different from the projector 1000 according to the first embodiment in the structure of the second lens array, as shown in FIG. 9A.
That is, in the projector 1000B according to the second embodiment, among the small lenses of the second lens array 130B, between the first row of small lenses and the second row of small lenses, and the third row of small lenses and the fourth row of lenses. A concave surface portion is provided between the small lens. For this reason, the weight of the second lens array and thus the projector can be reduced. Further, by providing such a concave surface portion, it is possible to shorten the cooling time when the second lens array is manufactured, and it is possible to reduce the manufacturing time and the manufacturing cost.

  As described above, the projector 1000B according to the second embodiment is different from the projector 1000 according to the first embodiment in the structure of the second lens array, but the liquid crystal is similar to the projector 1000 according to the first embodiment. Of the vertical and horizontal directions in the image forming areas of the devices 400R, 400G, and 400B (not shown), the entire image forming area in the horizontal direction along the x-axis direction and the vertical direction in the y-axis direction. An illumination light beam having a cross-sectional shape that illuminates a part of the image forming area (that is, a cross-sectional shape compressed in the vertical direction) is synchronized with the screen writing frequency of the liquid crystal device along the vertical direction on the image forming area. In order to be able to scan, in the image forming area of the liquid crystal devices 400R, 400G, and 400B, the light irradiation area and the light non-irradiation area are sequentially crossed. So it is scrolled. As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.

  Further, according to the projector 1000B according to the second embodiment, the planar shape of each small lens 122 is compressed in the vertical direction as the first lens array 120 using the illumination light beam having the cross-sectional shape compressed in the vertical direction as described above. Since this is realized by using a lens array, unlike in the case of using an optical shutter, illumination light beams emitted from the light source device 110 (not shown) can be used without waste in the image forming areas of the liquid crystal devices 400R, 400G, and 400B. Thus, the light utilization efficiency is not significantly reduced.

  For this reason, the projector 1000B according to the second embodiment is a projector in which the light use efficiency is not significantly reduced even when smooth and high-quality moving image display is obtained.

[Embodiment 3]
FIG. 10 is a diagram for explaining the structure of the second lens array in the third embodiment. FIG. 10A is a diagram schematically showing a locus of light rays from the first lens array to the polarization conversion element, and FIG. 10B is a diagram showing an arc image in the second lens array and the polarization conversion element. is there. 10, the same members as those in FIG. 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

As shown in FIG. 10A, a projector 1000C (not shown) according to the third embodiment is different from the projector 1000 according to the first embodiment in the structure of the second lens array.
That is, in the projector 1000C according to the third embodiment, among the small lenses of the second lens array 130C, between the first row of small lenses and the second row of small lenses, and the third row of small lenses and the fourth row of lenses. The small lens is connected smoothly. Thereby, since it is not necessary to make this part into a high-precision lens, it is possible to reduce the manufacturing cost of the mold when manufacturing the second lens array by press working.

  As described above, the projector 1000C according to the third embodiment is different from the projector 1000 according to the first embodiment in the structure of the second lens array, but as in the case of the projector 1000 according to the first embodiment, the liquid crystal Of the vertical and horizontal directions in the image forming areas of the devices 400R, 400G, and 400B (not shown), the entire image forming area in the horizontal direction along the x-axis direction and the vertical direction in the y-axis direction. An illumination light beam having a cross-sectional shape that illuminates a part of the image forming area (that is, a cross-sectional shape compressed in the vertical direction) is synchronized with the screen writing frequency of the liquid crystal device along the vertical direction on the image forming area. In order to be able to scan, in the image forming area of the liquid crystal devices 400R, 400G, and 400B, the light irradiation area and the light non-irradiation area are sequentially crossed. So it is scrolled. As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.

  Further, according to the projector 1000C according to the third embodiment, the planar shape of each small lens 122 is compressed in the vertical direction as the first lens array 120 using the illumination light beam having the cross-sectional shape compressed in the vertical direction as described above. Since this is realized by using a lens array, unlike in the case of using an optical shutter, illumination light beams emitted from the light source device 110 (not shown) can be used without waste in the image forming areas of the liquid crystal devices 400R, 400G, and 400B. Thus, the light utilization efficiency is not significantly reduced.

  For this reason, the projector 1000C according to the third embodiment is a projector in which the light use efficiency is not significantly reduced even when smooth and high-quality moving image display is obtained.

[Embodiment 4]
FIG. 11 is a diagram for explaining the structures of the first lens array, the second lens array, and the polarization conversion element in the fourth embodiment. FIG. 11A is a diagram schematically showing the locus of light rays from the first lens array to the polarization conversion element, and FIG. 11B is a diagram showing arc images in the second lens array and the polarization conversion element. is there.

  A projector 1000D (not shown) according to the fourth embodiment is different from the projector 1000 according to the first embodiment in the configuration of the polarization conversion element, as shown in FIG. In addition, the structures of the first lens array and the second lens array are different as the configuration of the polarization conversion element is different.

  In other words, in the projector 1000 according to the first embodiment, as described above, the polarization separation surfaces of the polarization separation prisms in the second and third columns of the polarization separation prisms illuminate the illumination light beam related to the second polarization component. It is configured to reflect in a direction away from the optical axis 100ax. On the other hand, in the projector 1000D according to the fourth embodiment, the polarization separation surfaces in the polarization separation prisms in the second and third columns of the polarization separation prisms convert the illumination light beam related to the second polarization component to the illumination optical axis 100Dax. It is comprised so that it may reflect in the direction approaching.

As described above, the projector 1000D according to the fourth embodiment is different from the projector 1000 according to the first embodiment in the configuration of the polarization conversion element, but as in the case of the projector 1000 according to the first embodiment, Since the polarization separation surfaces in the polarization separation prisms in the eyes and the fourth column reflect the illumination light beam related to the second polarization component in a direction approaching the illumination optical axis 100Dax, one column in the second lens array 130D. The partial light flux that passes through the small lenses in the eyes and the fourth row is positioned farther from the illumination optical axis 100Dax than in the past.
For this reason, the illumination light beam corresponding to this partial light beam does not need to be subjected to the refractive power directed to the illumination optical axis 100Dax as in the conventional case by the first lens array 120D, and therefore the first and fourth columns in the first lens array 120D. There is no need to decenter the small lenses 122D (not shown) in the row. As a result, the lens thickness of the first lens array 120D can be reduced, so that the weight of the first lens array and thus the projector can be reduced. In addition, since it is possible to reduce the lens thickness of the first lens array 120D, it is possible to reduce the cooling time when the first lens array is manufactured using press working, thereby reducing the manufacturing time. In addition, the manufacturing cost can be reduced.

In the projector 1000D according to the fourth embodiment, among the small lenses of the second lens array 130D, the second row of small lenses and the third row of small lenses are smoothly connected. Thereby, since it is not necessary to make this part into a high-precision lens, it is possible to reduce the manufacturing cost of the mold when manufacturing the second lens array by press working.
In the projector 1000D according to the fourth embodiment, among the small lenses of the second lens array 130D, the small lens in the second row and the small lens in the third row are connected smoothly, but the connection is made smoothly. Instead of this, a structure in which a concave portion is provided may be used. This can reduce the weight of the second lens array and thus the projector. Further, by providing such a concave surface portion, it is possible to shorten the cooling time when the second lens array is manufactured, and it is possible to reduce the manufacturing time and the manufacturing cost.

  As described above, the projector 1000D according to the fourth embodiment is different from the projector 1000 according to the first embodiment in the configuration of the first lens array, the second lens array, and the polarization conversion element. As in the case of the projector 1000, among the vertical and horizontal directions in the image forming areas of the liquid crystal devices 400R, 400G, and 400B (not shown), in the horizontal direction along the x-axis direction, the entire image forming area is the y-axis. In the vertical direction along the direction, an illumination light beam having a cross-sectional shape that illuminates a part of the image forming region (that is, a cross-sectional shape compressed in the vertical direction) is synchronized with the screen writing frequency of the liquid crystal device. In the image forming area of the liquid crystal devices 400R, 400G, and 400B, scanning can be performed along the vertical direction on the forming area. The irradiated region and a light non-irradiated area is to be scrolled in sequence alternately. As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.

  Further, according to the projector 1000D according to the fourth embodiment, the illumination light beam having the cross-sectional shape compressed in the vertical direction as described above is compressed in the vertical direction as the planar shape of each small lens 122D as the first lens array 120D. Since this is realized by using a lens array, unlike in the case of using an optical shutter, illumination light beams emitted from the light source device 110 (not shown) can be used without waste in the image forming areas of the liquid crystal devices 400R, 400G, and 400B. Thus, the light utilization efficiency is not significantly reduced.

  For this reason, the projector 1000D according to the fourth embodiment is a projector in which the light use efficiency is not significantly reduced even when smooth and high-quality moving image display is obtained.

[Embodiment 5]
FIG. 12 is a diagram illustrating an optical system of the projector according to the fifth embodiment. FIG. 12A is a diagram of the optical system viewed from the top, and FIG. 12B is a diagram of the optical system viewed from the side.

As shown in FIG. 12A, the projector 1000E according to the fifth embodiment is different from the projector 1000 according to the first embodiment in the configuration of the color separation optical system.
That is, in the projector 1000E according to the fifth embodiment, as the color separation optical system 200B, the direction in which the light irradiation region and the light non-irradiation region are scrolled on each of the liquid crystal devices 400R, 400G, and 400B is the same direction. Therefore, a double relay optical system is used.

  As described above, the projector 1000E according to the fifth embodiment differs from the projector 1000 according to the first embodiment in the configuration of the color separation optical system, but as in the case of the projector 1000 according to the first embodiment, the liquid crystal devices 400R, Of the vertical and horizontal directions in the 400G and 400B image forming areas, the entire image forming area is illuminated in the horizontal direction along the x-axis direction, and a part of the image forming area is illuminated in the vertical direction along the y-axis direction. The illumination light beam having such a cross-sectional shape (that is, a cross-sectional shape compressed in the vertical direction) can be scanned along the vertical direction on the image forming region in synchronization with the screen writing frequency of the liquid crystal device. In the image forming areas of the liquid crystal devices 400R, 400G, and 400B, the light irradiation area and the light non-irradiation area are sequentially scrolled alternately. . As a result, the tailing phenomenon is alleviated and a smooth and high-quality moving image display can be obtained.

  Further, according to the projector 1000E according to the fifth embodiment, the planar shape of each small lens 122 is compressed in the vertical direction as the first lens array 120 using the illumination light beam having the cross-sectional shape compressed in the vertical direction as described above. Since this is realized by using the lens array, unlike the case of using the optical shutter, the illumination light beam emitted from the light source device 110 can be guided to the image forming areas of the liquid crystal devices 400R, 400G, and 400B without waste. Thus, the light use efficiency is not greatly reduced.

  For this reason, the projector 1000E according to the fifth embodiment is a projector in which the light use efficiency is not significantly reduced even when smooth and high-quality moving image display is obtained.

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

(1) Although the projectors 1000 to 1000E in the above embodiments are transmissive projectors, the present invention can also be applied to a reflective projector. Here, “transmission type” means that an electro-optic modulation device as a light modulation means, such as a transmission type liquid crystal display device, transmits light, and “reflection type” means This means that an electro-optic modulation device as a light modulation means, such as a reflective liquid crystal display device, is a type that reflects light. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

(2) Although the projectors 1000 to 1000E of the above embodiments use a liquid crystal device as an electro-optic modulation device, the present invention is not limited to this. In general, the electro-optic modulation device may be any device that modulates incident light in accordance with image information, and a micromirror light modulation device or the like may be used. For example, a DMD (digital micromirror device) (trademark of TI) can be used as the micromirror light modulator.

(3) In the projectors 1000 to 1000E of the above-described embodiments, the planar shape of the small lenses 122 and 122D of the first lens arrays 120 and 120D is “vertical dimension: lateral dimension = 1: 4 rectangle” and Although “longitudinal dimension: lateral dimension = 9: 32 rectangle” is used, the present invention is not limited to this, and for example, “vertical dimension: lateral dimension = 3: 8 rectangle” is also preferably used. be able to.

(4) The projectors 1000 to 1000E of the above embodiments use the rotating prism 770 as the scanning unit. However, the present invention is not limited to this, and for example, a galvanometer mirror, a polygon mirror, or the like can be preferably used.

(5) The projectors 1000 to 1000E of the above-described embodiments are light sources that include the ellipsoidal reflector 114, the arc tube 112 having the emission center near the first focal point of the ellipsoidal reflector 114, and the concave lens 118 as the light source device 110. Although the device is used, the present invention is not limited to this, and a light source device having a parabolic reflector and an arc tube having an emission center near the focal point of the parabolic reflector can be preferably used.
(6) In the above embodiments, only examples of projectors using the three liquid crystal devices 400R, 400G, and 400B are given. However, the present invention is also applicable to projectors using less than three, or four or more liquid crystal devices. Is applicable.
(7) 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 has been described. However, the present invention provides a rear that projects an image from the side opposite to the direction of observing the screen. It is also applicable to a type of projector.

FIG. 3 is a diagram for explaining the projector according to the first embodiment. The figure shown in order to demonstrate the shape of the ellipsoidal reflector and auxiliary | assistant mirror in Embodiment 1. FIG. FIG. 3 is a view for explaining the structure of a first lens array in the first embodiment. FIG. 4 is a diagram for explaining a structure of a first lens array according to a comparative example of the first embodiment. The figure which shows the light intensity distribution in the cross section of an illumination light beam by a contour line. FIG. 3 is a view for explaining the structure of the polarization conversion element in the first embodiment. FIG. 3 is a view for explaining the structure of a polarization conversion element in a comparative example of the first embodiment. The figure which shows the relationship between rotation of a rotation prism, and the illumination state on a liquid crystal display device. FIG. 6 is a diagram for explaining a structure of a second lens array in the second embodiment. FIG. 6 is a diagram for explaining a structure of a second lens array in the third embodiment. FIG. 9 is a diagram for illustrating the structures of a first lens array, a second lens array, and a polarization conversion element in a fourth embodiment. FIG. 10 is a diagram illustrating an optical system of a projector according to a fifth embodiment. The figure shown in order to demonstrate the conventional projector. The figure shown in order to demonstrate another conventional projector.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Illuminating device, 100ax, 100aax, 100Bax, 100Cax, 100Dax ... Illumination optical axis, 110 ... Light source device, 112 ... Light emitting tube, 114 ... Ellipsoidal reflector, 116 ... Auxiliary mirror, 118 ... Concave lens, 120, 120D ... 1st Lens array 122 ... Small lens 130, 130B, 130C, 130D Second lens array 140, 140D Polarization conversion element 200, 200B Color separation optical system 400R 400G 400B Liquid crystal device 500 Cross Dichroic prism, 600 ... projection optical system, 770 ... rotating prism, 772 ... rotating axis, 900A, 900B, 1000, 1000E ... projector, P ... image of virtual center point of first lens array on illumination optical axis, SCR ... screen .

Claims (15)

A light source device that emits an illumination light beam toward the illuminated region, a first lens array having a plurality of small lenses for dividing the illumination light beam emitted from the light source device into a plurality of partial light beams, and the first lens array A second lens array having a plurality of small lenses corresponding to a plurality of small lenses, a polarization conversion element for converting non-polarized light contained in an illumination light beam emitted from the second lens array into polarized light, and the polarization conversion An illuminating device having a superimposing lens for superimposing each partial light beam emitted from the element in the illuminated area;
An electro-optic modulation device that modulates an illumination light beam emitted from the illumination device according to image information;
A projection optical system that projects the illumination light beam modulated by the electro-optic modulation device,
Each small lens in the first lens array emits the illumination light beam emitted from the illumination device, the entire image formation region in one of the vertical and horizontal directions in the image formation region of the electro-optic modulation device, and the other The direction has a planar shape compressed in the other direction so as to have an illumination light beam having a cross-sectional shape that illuminates a part of the image forming region,
A scanning unit that scans the illumination light beam along the other direction on the image forming region in synchronization with a screen writing frequency of the electro-optic modulation device is further provided between the illumination device and the electro-optic modulation device. Projector,
The light source device emits an illumination light beam that spreads toward the illuminated area,
The plurality of small lenses in the first lens array are arranged along the one direction and the other direction,
The polarization conversion element includes a polarization separation element that separates the illumination light beam into an illumination light beam according to a first polarization component and an illumination light beam according to a second polarization component, and the first light beam separated by the polarization separation element. A phase difference plate that converts one of the illumination light beam related to the polarization component and the illumination light beam related to the second polarization component into the other, and
The polarization separation element transmits the illumination light beam related to the first polarization component of the two polarization components included in the illumination light beam as it is and reflects the illumination light beam related to the second polarization component in a direction perpendicular to the illumination optical axis. A plurality of polarization separation prisms each having a polarization separation surface that reflects and a reflection surface that reflects the second polarization component in a direction parallel to the illumination optical axis,
The plurality of polarization separation prisms are arranged along the one direction,
The polarization separation surfaces of the polarization separation prisms at both ends in one direction of the polarization separation element among the plurality of polarization separation prisms are configured to reflect the illumination light flux related to the second polarization component in a direction approaching the illumination optical axis. The projector characterized by being made. The projector according to claim 1, wherein
In the plurality of small lenses of the first lens array, the rows along the one direction are arranged in four rows along the other direction,
In the plurality of small lenses of the second lens array, the rows along the one direction are arranged in four rows along the other direction,
The plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array,
Of the plurality of polarization separation prisms, the polarization separation surfaces in the first and fourth polarization separation prisms are configured to reflect the illumination light flux related to the second polarization component in a direction approaching the illumination optical axis. The polarization separation surfaces in the polarization separation prisms in the second row and the third row are configured to reflect the illumination light beam related to the second polarization component in a direction away from the illumination optical axis. . The projector according to claim 1 or 2,
In the plurality of small lenses of the first lens array, the rows along the one direction are arranged in four rows along the other direction,
In the plurality of small lenses of the second lens array, the rows along the one direction are arranged in four rows along the other direction,
The plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array,
Of the small lenses of the second lens array, concave portions are provided between the first row of small lenses and the second row of small lenses and between the third row of small lenses and the fourth row of small lenses. A projector characterized by being made. The projector according to claim 1 or 2,
In the plurality of small lenses of the first lens array, the rows along the one direction are arranged in four rows along the other direction,
In the plurality of small lenses of the second lens array, the rows along the one direction are arranged in four rows along the other direction,
The plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array,
Of the small lenses of the second lens array, the small lens in the first row and the small lens in the second row and the small lens in the third row and the small lens in the fourth row are connected smoothly. A projector characterized by having The projector according to claim 1, wherein
In the plurality of small lenses of the first lens array, the rows along the one direction are arranged in four rows along the other direction,
In the plurality of small lenses of the second lens array, the rows along the one direction are arranged in four rows along the other direction,
The plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array,
Among the polarization separation prisms, the polarization separation surfaces in the first and fourth polarization separation prisms are configured to reflect the illumination light flux related to the second polarization component in a direction approaching the illumination optical axis. The projector according to claim 1, wherein the polarization separation surfaces in the polarization separation prisms in the third and third rows are configured to reflect the illumination light beam related to the second polarization component in a direction approaching the illumination optical axis. In the projector according to any one of claims 1 to 5,
The projector according to claim 1, wherein an optical axis of each small lens in the first lens array is within a width of each small lens in the one direction. In the projector according to any one of claims 1 to 6,
Each of the small lenses in the first lens array has a larger amount of decentering in the other direction as the smaller lens is farther from the illumination optical axis in the row along the other direction. In the projector according to any one of claims 1 to 7,
In the first lens array, the plurality of small lenses are arranged in four rows along the other direction, the rows along the one direction,
The plurality of polarization separation prisms are arranged in four rows corresponding to the rows of the plurality of small lenses in the first lens array,
Each small lens in the first lens array has a decentering amount in the other direction of the small lenses in the second row and the third row as compared to the decentering amount in the other direction of the small lenses in the first row and the fourth row. A projector that is large. The projector according to any one of claims 2 to 8,
The projector according to claim 1, wherein the plurality of small lenses in the first lens array are arranged in 8 to 10 rows along the other direction. The projector according to any one of claims 1 to 9,
The light source device includes an arc tube having a light emitting part, an elliptical reflector that reflects light emitted from the light emitting part, and a concave lens that converts light reflected by the elliptical reflector into an illumination light beam that spreads toward an illuminated area. And an auxiliary mirror that reflects the light emitted from the light emitting unit toward the illuminated region to the light emitting unit,
The auxiliary mirror has a part of the reflective concave surface such that a length along the other direction in a cross section of the illumination light beam on the light incident surface of the first lens array is shorter than a length along the one direction. A projector characterized by having a deleted shape. The projector according to claim 10, wherein
The ellipsoidal reflector has a shape in which a portion of the concave concave surface required for reflecting the light passing therethrough is deleted when it is assumed that the light emitted from the light emitting unit passes without being reflected by the auxiliary mirror. A projector comprising: The projector according to claim 10 or 11,
The ratio of the length along the other direction to the length along the one direction in the cross section of the illumination light beam on the light incident surface of the first lens array is 30% to 80%. projector. The projector according to any one of claims 1 to 12,
The first lens array has a light incident surface closer to the ellipsoidal reflector than the second focal point of the ellipsoidal reflector, and the amount of illumination light beam emitted from the light source device on the light incident surface is distributed over the entire surface. A projector characterized by being arranged at such a position. The projector according to any one of claims 1 to 13,
A color separation optical system for separating an illumination light beam emitted from the illumination device into a plurality of color lights between the illumination device and the electro-optic modulation device;
As the electro-optic modulator, a plurality of electro-optic modulators that modulate a plurality of color lights emitted from the color separation optical system according to image information corresponding to the respective color lights,
A projector comprising: a dichroic prism that combines color lights modulated by the plurality of electro-optic modulators. The projector according to claim 14, wherein
The scanning unit includes a rotating prism that is disposed at a position substantially conjugate with the electro-optic modulation device between the illumination device and the color separation optical system and has a rotation axis perpendicular to the illumination optical axis,
The rotating prism is configured such that the light irradiation region and the light non-irradiation region are sequentially scrolled in synchronization with the screen writing frequency of the electro-optic modulation device on the electro-optic modulation device by the rotation. Projector.