JP4158789B2 - projector - Google Patents

Description

  The present invention relates to a projector.

FIG. 9 is a diagram for explaining a conventional projector. FIG. 9A is a diagram showing an optical system of a conventional projector, and FIGS. 9B and 9C 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. 9B, they are shown in FIG. 9C. 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. 10 is a diagram for explaining another conventional projector. FIG. 10A is a diagram showing an optical system of another conventional projector, and FIG. 10B and FIG. 10C are diagrams for showing an optical shutter used in such another conventional projector. It is.
In the projector 900B, as shown in FIG. 10A, optical shutters 420R, 420G, and 420B are arranged 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

  A projector according to an aspect of the present invention includes a light source device that emits a substantially parallel illumination light beam toward the illuminated region side, and a first lens 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. An array, a second lens array having a plurality of small lenses corresponding to the plurality of small lenses of the first lens array, and converting non-polarized light contained in an illumination light beam emitted from the second lens array into polarized light And an illumination device having a superimposing lens for superimposing each partial light beam emitted from the polarization conversion device in an illuminated area, and modulating the illumination light beam emitted from the illumination device according to image information And an optical projection system for projecting the illumination light beam modulated by the electro-optic modulator, and each small lens in the first lens array includes: The illumination light beam emitted from the illumination device is the entire image formation region in any one of the vertical and horizontal directions in the image formation region of the electro-optic modulation device, and a part of the image formation region in the other direction. A screen writing of the electro-optic modulation device between the illumination device and the electro-optic modulation device has a planar shape compressed in the other direction so as to have an illumination light beam having a cross-sectional shape to illuminate. A projector further comprising scanning means for scanning the illumination light beam along the other direction on the image forming region in synchronization with a frequency, wherein the light source device includes a light emitting tube having a light emitting unit, and a light emitting unit. An ellipsoidal reflector that reflects the emitted light, a collimating lens that makes the light reflected by the ellipsoidal reflector substantially parallel light, and emitted from the light emitting unit to the illuminated region side An auxiliary mirror that reflects the reflected light to the light emitting portion, and the auxiliary mirror has a length along the other direction in the cross section of the illumination light beam on the light incident surface of the first lens array in the one direction. A feature is that a part of the reflective concave surface is deleted so as to be shorter than the length along the length.

  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, the cross-sectional shape of the illumination light beam reflected by the ellipsoidal reflector is smaller in the other direction than in the one direction. Therefore, the dimension along the other direction of each optical element in the subsequent stage including the parallelizing lens, the first lens array, the second lens array, the polarization conversion element, and the superimposing lens can be shortened, and the entire apparatus can be downsized. Can be achieved. 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.

  As the electro-optic modulation device, the planar shape of the image forming area is widely “vertical dimension: horizontal dimension = 3: 4 rectangular” and “vertical dimension: horizontal dimension = 9: 16 rectangular”. 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 = “A rectangular shape of 9:32”, “a vertical size: a rectangular size of 1: 4”, and the like can be preferably used.

  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.

In the projector according to the aspect of the invention, the plurality of small lenses of the first lens array may be longer than the length along the one direction in the plane perpendicular to the central axis of the illumination light beam and along the other direction. Are arranged in a short, substantially rectangular region, and the shape of the cross section of the illumination light beam emitted from the illumination device is substantially the same as the shape of the substantially rectangular region in which the plurality of small lenses of the first lens array are arranged. It is preferable that the auxiliary mirror has a shape having a longitudinal direction in the other direction.
In the projector according to the aspect of the invention, it is preferable that the ellipsoidal reflector has a shape having a longitudinal direction in the one direction.

  With this configuration, the illumination light beam can be efficiently incident on the area where the plurality of small lenses are arranged, and the dimension along the other direction of the ellipsoidal reflector can be shortened. Further downsizing 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 section of the illumination light beam on the light incident surface of the first lens array may be 30% to 30%. 80% is preferable.

  When this ratio is less than 30%, it is not easy to maintain the light use efficiency of the illumination light beam emitted from 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 modulation device 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, it is preferable that the plurality of small lenses in the first lens array are arranged in four rows along the one direction.

  With this configuration, since the small lenses in the first lens array are arranged in four rows along one direction, the light intensity distribution in the illuminated area of the electro-optic modulation device can be made uniform to some extent. . 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, 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 first lens array has a light incident surface closer to the ellipsoidal reflector than the second focal point of the ellipsoidal reflector, and is emitted from the light source device on the light incident surface. It is preferable that the illumination light beam is disposed at a position where the light quantity of the illumination 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 arrange the first lens array at a position where there is no region (shadow region) with extremely small incident light intensity in 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, the projector may further include 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, It is preferable that 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 each color light are provided as the electro-optic modulator.

  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 be a rotation axis perpendicular to the illumination optical axis. The rotating prism sequentially scrolls the light irradiation area and the light non-irradiation area 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. 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 shown in order to demonstrate the illuminating device in the projector which concerns on.
In the following description, the three directions orthogonal to each other are the z-axis direction (illumination optical axis direction in FIG. 1A) and the x-axis direction (parallel to the paper surface in FIG. 1A and orthogonal to the z-axis). Direction) and the y-axis direction (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 FIG. 1A and FIG. 1B, the illumination device 100 emits a plurality of illumination light beams emitted from the light source device 110 that emits a substantially parallel illumination light beam toward the illuminated region side, and 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 polarization conversion element 140 for converting the illumination light beam into substantially one type of linearly polarized light, and a superimposition for superimposing the partial light beams emitted from the polarization conversion element 140 in the illuminated region. A lens 150 is included.

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 collimating lens 118 for converting the focused light reflected by the light into substantially parallel 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. To divide.
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, and each partial light beam is condensed so as to enter the polarization separation surface of the polarization conversion element 140.
The polarization conversion element 140 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 100ax. A polarization separation surface for reflecting, a reflection surface for reflecting the second polarization component in a direction parallel to the illumination optical axis, and a retardation plate for converting one of the first polarization component and the second polarization component into the other. I have. The partial light beam emitted from the second lens array 130 is converted into substantially one type of linearly polarized light by the polarization conversion element 140. 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, as in the liquid crystal devices 400R, 400G, and 400B of the projector 1000 according to the first embodiment. In addition, the illumination light beam is suitable when an electro-optic modulation device of a type 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, 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 FIGS. 1A and 1B, 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 244, 246, 248 and the liquid crystal devices 400R, 400G, 400B, respectively, and are crossed with the liquid crystal devices 400R, 400G, 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, the auxiliary mirror 116, the first lens array 120, and the rotating prism 770 in the projector 1000 according to the first embodiment will be described in detail.

1. First Lens Array FIGS. 3A to 3C are views for explaining the structure of the first lens array 120 in the first embodiment. 3A is a view of the first lens array 120 as viewed from the direction along the z-axis direction, and FIG. 3B is a view as viewed from the direction along the y-axis direction. ) Is a view from the direction along the x-axis direction. FIG. 4A to FIG. 4B are diagrams showing the light intensity distribution in the cross section of the illumination light beam by contour lines. FIG. 4A is a diagram showing the light intensity distribution of the illumination light beam on the light incident surface of the first lens array 120. FIG. 4B is a diagram showing the light intensity distribution 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. 3, the first lens array 120 includes a plurality of small lenses 122 for dividing an illumination light beam emitted from the light source device 110 (see FIG. 1) into a plurality of partial light beams, and a plurality of small lenses. And a non-lens region 124 provided so as to surround 122.
As shown in FIG. 3A, each small lens 122 in the first lens array 120 has a planar shape of “vertical dimension along the y-axis direction: lateral dimension along the x-axis direction = 1: 4 rectangle”. have. For this reason, the first lens array 120 illuminates the illumination light beam emitted from the illumination device 100 over the entire image formation region in the lateral direction along the x-axis direction in the image formation regions of the liquid crystal devices 400R, 400G, and 400B. In the longitudinal direction along the y-axis direction, the shape of the light beam can be transformed into a plurality of partial light beams having a cross-sectional shape that illuminates a part (about half) of the image forming region. That is, the planar shape of each small lens 122 of the first lens array 120 is set to be substantially similar to the shape of the illumination area in the image forming area of each liquid crystal device 400R, 400G, 400B.
Then, the plurality of partial light beams emitted from the first lens array 120 are superimposed by the second lens array 130 and the superimposing lens 150, and are expressed as “longitudinal dimension along the y-axis direction: lateral dimension along the x-axis direction”. = 1: 4 rectangle ”is illuminated.

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, since the light source image pitch 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, the second The number of light source images is limited so that the size of the optical system after the 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 to the small lenses of the second lens array 130 that respectively correspond to the partial light beams divided by the first lens array will be incident. Non-partial light fluxes are 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.
In the projector 1000 according to the first embodiment, the plurality of small lenses 122 in the first lens array 120 are arranged in four rows along the x-axis direction, as shown in FIG. 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 rows along the x-axis direction, the partial light beams emitted from the small lenses 122 of the first lens array 120 correspond to the corresponding first lenses. The size of the small lens 122 can be ensured so that the two-lens array 130 is satisfactorily swallowed. For this reason, favorable light utilization efficiency is obtained for the light that illuminates the illumination area with respect to the light emitted from the light source device 110.

  In the projector 1000 according to the first embodiment, the plurality of small lenses 122 in the first lens array 120 are arranged in 10 rows along the y-axis direction, as shown in FIG. For this reason, the size of the small lens 122 can be ensured so that the partial light beams emitted from the small lenses 122 of the first lens array 120 are satisfactorily swallowed by the corresponding second lens array 130. 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.

In the projector 1000 according to the first embodiment, the ratio of the length in the vertical direction along the y-axis direction to the length in the horizontal direction along the x-axis direction is as shown in FIG. A plurality of small lenses 122 of the first lens array 120 are arranged in a region where length: length in the vertical direction = 8: 5. That is, the plurality of small lenses 122 are arranged in a rectangular region in which the ratio of the length in the vertical direction along the y-axis direction to the length in the horizontal direction along the x-axis direction is about 63%.
For this reason, since the ratio of the length in the vertical direction along the y-axis direction to the length in the horizontal direction along the x-axis direction is 30% or more, the light utilization of the illumination light beam emitted from the ellipsoidal reflector 114 is used. Efficiency can be maintained.
According to this embodiment, the size of the small lens 122 is ensured so that the partial light beams emitted from the small lenses 122 of the first lens array 120 are satisfactorily swallowed by the corresponding second lens array 130. Since the number of rows and columns of the small lenses 122 in the first lens array 120 can be ensured and divided into a plurality of partial light beams, the light intensity distribution on the liquid crystal devices 400R, 400G, and 400B can be made uniform. It becomes possible. Further, since the ratio of the length in the vertical direction along the y-axis direction to the length in the horizontal direction along the x-axis direction 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 arrange | positions in the position where the light quantity of the illumination light beam to distribute is distributed over the whole. For this reason, 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, the manufacturing process in the first lens array 120 can be simplified and the cost can be reduced.

  In this case, it is preferable that the first lens array 120 is arranged 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 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.

2. 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.

As shown in FIGS. 1 and 2, 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.
In other words, the “longitudinal dimension along the y-axis direction: the lateral dimension along the x-axis direction = 1: 4 rectangle” the small lens 122 is lateral in the plane perpendicular to the illumination light beam 100ax that is the central axis of the illumination light beam. Length: length in the vertical direction = 8: 5, the auxiliary mirror 116 has a longitudinal direction in the vertical 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 length in the horizontal direction in which the small lenses 122 in the first lens array 120 are arranged: the length in the vertical direction = 8: 5. Therefore, the light emitted from the light source device 100 can be used without waste.
In addition, the vertical dimension along the y-axis direction of each optical element in the subsequent stage including the collimating lens 118, the first lens array 120, the second lens array 130, the polarization conversion element 140, and the superimposing lens 150 may be shortened. Thus, the entire apparatus can be reduced in size.

  Furthermore, in the projector 1000 according to the first embodiment, the ellipsoidal reflector 114 assumes that the light emitted from the arc tube 112 passes without being reflected by the auxiliary mirror 116, as shown in FIGS. Further, the reflection concave surface portion required for reflecting the passing light 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.

3. Rotating Prism FIGS. 5A to 5C are diagrams showing the relationship between the rotation of the rotating prism 770 and the illumination state on the liquid crystal device 400R (400G and 400B are the same). FIG. 5A is a cross-sectional view of the rotating prism 770 when viewed along the rotation axis 772. FIG. 5B is a view of the rotating prism 770 when viewed along the illumination optical axis 100ax. FIG. 5C is a diagram showing an irradiation 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. 5A and FIG. 5B, 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. 5C, when the rotating prism 770 rotates, the light irradiation area and the light non-irradiation area are scrolled alternately in the image forming area of the liquid crystal devices 400R, 400G, and 400B. become.

  As described above, the ellipsoidal reflector 114, the auxiliary mirror 116, the first lens array 120, and the rotating prism 770 in the projector 1000 according to the first embodiment have been described in detail. However, the projector 1000 according to the first embodiment also has the following characteristics. Have.

  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.

  For this reason, according to the projector 1000 according to the first embodiment, among the vertical and horizontal directions in the image forming areas of the liquid crystal devices 400R, 400G, and 400B, the entire image forming area in the horizontal direction along the x-axis direction is the y-axis. In the vertical direction along the direction, the illumination light flux having a cross-sectional shape that illuminates a part of the image forming region (that is, the cross-sectional shape compressed in the vertical direction) is used as the screen writing frequency of the liquid crystal devices 400R, 400G, and 400B. Since the image forming area can be scanned along the y-axis direction in synchronization with the image forming area, the light irradiation area and the light non-irradiation area are alternately alternated in the image forming area of the liquid crystal devices 400R, 400G, and 400B. It will be scrolled to. 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 used as the first lens array 120 and the planar shape of each small lens 122 (see FIG. 3). Unlike the case where an optical shutter is used, the illumination light beam emitted from the light source device 110 can be used without waste in the image forming areas of the liquid crystal devices 400R, 400G, and 400B. As a result, the light utilization efficiency is not significantly 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.

[Embodiment 2]
FIG. 6 is a diagram for explaining the structure of the first lens array in the second embodiment. FIG. 6A is a view of the first lens array as viewed from the direction along the z-axis direction, and FIG. 6B is a view as viewed from the direction along the y-axis direction. These are the figures seen from the direction along the x-axis direction. FIG. 7 is a diagram showing the light intensity distribution in the cross section of the illumination light beam by contour lines. FIG. 7A is a diagram showing the light intensity distribution of the illumination light beam on the light incident surface of the first lens array. FIG. 7B is a diagram showing the light intensity distribution of the illumination light beam on the image forming area of the liquid crystal device.

  The projector 1000B (not shown) according to the second embodiment is different from the projector 1000 according to the first embodiment in the configuration of the first lens array (and the configuration of the second lens array associated therewith). That is, in the projector 1000 according to the first embodiment, the first lens array 120 is provided so as to surround the small lenses 122 arranged in four columns and ten rows and these small lenses 122, as shown in FIG. In contrast to the non-lens region 124, in the projector 1000B according to the second embodiment, the first lens array 120B includes small lenses 122B arranged in four columns and eight rows as shown in FIG. And a non-lens region 124B provided so as to surround these small lenses 122B.

Each small lens 122B in the first lens array 120B has a “vertical dimension along the y-axis direction: a lateral dimension along the x-axis direction = 1: 4 rectangle” as shown in FIG. 6A. It has a planar shape. Therefore, the first lens array 120B causes the illumination light beam emitted from the illumination device 100 (not shown) to be in the x-axis direction in the image forming area of each liquid crystal device 400R, 400G, 400B (not shown). An illumination light beam having a cross-sectional shape that illuminates the entire image forming region in the horizontal direction along the vertical direction and a part (about half) of the image forming region in the vertical direction along the y-axis direction can be obtained. .
Further, in the projector 1000B according to the second embodiment, in the cross section of the illumination light beam on the light incident surface of the first lens array 120B, the vertical direction along the y-axis direction with respect to the horizontal length along the x-axis direction. As shown in FIG. 7A, the length ratio is the length in the horizontal direction: the length in the vertical direction = 2: 1. That is, the ratio of the length in the vertical direction along the y-axis direction to the length in the horizontal direction along the x-axis direction is 50%.

  As described above, the projector 1000B according to the second embodiment differs from the projector 1000 according to the first embodiment in the configuration of the first lens array (and the configuration of the second lens array associated therewith). As in the case of the projector 1000 according to No. 1, among the vertical and horizontal directions in the image forming areas of the liquid crystal devices 400R, 400G, and 400B, in the horizontal direction along the x-axis direction, the entire image forming area is aligned along the y-axis direction. In the vertical 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 devices 400R, 400G, and 400B. Thus, it becomes possible to scan along the y-axis direction on the image forming area, and thus the liquid crystal devices 400R, 400G, and 400B. So that a light irradiation area and the light non-irradiated region are scrolled successively alternately in the image forming area. 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 illumination light beam having the cross-sectional shape compressed in the vertical direction as described above is compressed in the vertical direction as the first lens array 120B in the planar shape of each small lens 122B. Since this is realized by using a lens array, 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 unlike the case of using an optical shutter. Thus, the light use 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. 8 is a diagram illustrating an optical system of the projector according to the third embodiment. FIG. 8A is a view of the optical system as viewed from above, and FIG. 8B is a view of the optical system as viewed from side.

As shown in FIG. 8A, the projector 1000C according to the third 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 1000C according to the third embodiment, as the color separation optical system 200B, the light irradiation region and the light non-irradiation region are scrolled in the same direction on the liquid crystal devices 400R, 400G, and 400B. Therefore, a double relay optical system is used.

  As described above, the projector 1000C according to the third 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 device 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) is scanned along the y-axis direction on the image forming region in synchronization with the screen writing frequency of the liquid crystal devices 400R, 400G, and 400B. Therefore, in the image forming area of the liquid crystal devices 400R, 400G, and 400B, a light irradiation area and a light non-irradiation area are sequentially formed. Each other so that 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 1000 according to the third embodiment, the illumination light beam having the cross-sectional shape compressed in the vertical direction as described above is used to compress the planar shape of each small lens 122 in the vertical direction as the first lens array 120. Since this is realized by using a lens array, 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 unlike the case of using an optical shutter. Thus, the light use efficiency is not significantly reduced.

  For this reason, the projector 1000 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.

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

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

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

(4) In the projectors 1000 to 1000C of the above embodiments, the rotating prism 770 is used 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 1000C of the above embodiments include, as the light source device 110, an ellipsoidal reflector 114, an arc tube 112 having a light emission center near the first focal point of the ellipsoidal reflector 114, and a collimating lens 118. However, the present invention is not limited to this, and a light source device having a paraboloid reflector and an arc tube having an emission center near the focal point of the paraboloid 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. The figure which shows the light intensity distribution in the cross section of an illumination light beam by a contour line. The figure which shows the relationship between rotation of a rotation prism, and the illumination state on a liquid crystal device. FIG. 6 is a diagram for explaining a structure of a first lens array in the second embodiment. The figure which shows the light intensity distribution in the cross section of an illumination light beam by a contour line. FIG. 10 is a diagram illustrating an optical system of a projector according to a third embodiment. The figure shown in order to demonstrate the conventional projector. The figure shown in order to demonstrate another conventional projector.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Illuminating device, 110 ... Light source device, 112 ... Light-emitting tube, 114 ... Ellipsoidal reflector, 116 ... Auxiliary mirror, 118 ... Parallelizing lens, 120, 120B ... First lens array, 122, 122B ... Small lens, 124, 124B ... non-lens area, 130 ... second lens array, 140 ... polarization conversion element, 150 ... superimposed lens, 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 shaft, 900A, 900B, 1000, 1000C, projector, P, image of the virtual center point of the first lens array on the illumination optical axis, SCR, screen.

Claims (10)

A first light source device that emits a substantially parallel illumination light beam toward the illuminated area, 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 A second lens array having a plurality of small lenses corresponding to the plurality of small lenses of the array, a polarization conversion element for converting unpolarized light contained in an illumination light beam emitted from the second lens array into polarized light, and An illuminating device having a superimposing lens for superimposing each partial light beam emitted from the polarization conversion element in an 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 is
An arc tube having a light emitting portion, and a pair of sealing portions extending from both ends of the light emitting portion,
An ellipsoidal reflector that is attached to one sealing portion of the pair of sealing portions and reflects light emitted from the light emitting portion;
A collimating lens that makes light reflected by the ellipsoidal reflector substantially parallel light ;
An auxiliary mirror that is attached to the other sealing portion of the pair of sealing portions and reflects light emitted from the light emitting portion toward the illuminated region to the light emitting portion ;
Further comprising
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 1, 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: In the projector according to claim 1 or 2,
The plurality of small lenses of the first lens array are in a substantially rectangular region in a plane perpendicular to the central axis of the illumination light beam and having a length along the other direction shorter than a length along the one direction. Are arranged in
The shape of the cross section of the illumination light beam emitted from the illumination device is substantially the same as the shape of a substantially rectangular region in which a plurality of small lenses of the first lens array are arranged,
The auxiliary mirror has a shape having a longitudinal direction in the other direction. The projector according to claim 3, wherein
The ellipsoidal reflector has a shape having a longitudinal direction in the one direction. In the projector according to any one of claims 1 to 4,
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. In the projector according to any one of claims 1 to 5,
The projector according to claim 1, wherein the plurality of small lenses in the first lens array are arranged in four rows along the one direction. The projector according to any one of claims 1 to 4,
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. In the projector according to any one of claims 1 to 5,
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 is distributed over the light incident surface. A projector characterized by being arranged in such a position. The projector according to any one of claims 1 to 8,
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;
A projector comprising: 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 as the electro-optic modulation device. . The projector according to claim 9, 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.