JP2008209730A - Polarizing illumination device and projection display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing illumination device adjusting light quantity by a diaphragm device at high speed, suppressing unevenness of illuminance and color and flicker from occurring, and projecting a higher-quality image. <P>SOLUTION: Two movable light shielding plates 26A and 26B are driven to slide by the same distance in an opposite direction to each other. The area of each polarizing beam splitter shielded from light by the parts (light shielding parts) other than the light transmitting parts 80 and 82 of the two movable light shielding plates 26A and 26B is equally increased (opening area is equally decreased) from both sides in its width direction. During such a period, the center position in the width direction of a slit-like aperture constituted by the light transmitting parts 80 and 82 of the two movable light shielding plates 26A and 26B does not move, and the positions of the center axis of the slit-like aperture and the center axis of the polarizing beam splitter are fixed any time regardless of the opening degree of the diaphragm device 46. Therefore, projected light excelling in symmetry is always obtained regardless of the opening degree of the diaphragm device 46. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to a polarization illumination device and a projection display device used in a projection type high definition television (HDTV) system, a video projector, and the like.

  An illumination device used in a projection-type high-definition television (HDTV) system or a video projector needs to uniformly illuminate a rectangular illumination area, and various illumination devices have been proposed to satisfy the demand. . For example, there is an illumination device called an integrator optical system used with a liquid crystal light valve. In this method, light from a light source is divided by a lens plate (first lens array) composed of a plurality of rectangular condenser lenses (referred to as “unit lenses” in this description), and is cut out by each rectangular condenser lens. Each partial light beam is superimposed and imaged on one illumination area via a lens plate (second lens array) composed of a plurality of rectangular condenser lenses in the same manner as the first lens plate. is there.

  In addition, the twisted nematic liquid crystal used in the liquid crystal light valve performs display by changing the polarization direction of linearly polarized light. Therefore, it is possible to linearly polarize natural light from the light source. It is desirable for improving the utilization rate of light. Therefore, an illumination device called a polarization optical system having the polarization beam splitter array 10 shown in FIGS. 11 and 12 has been developed. The polarization beam splitter array 10 used here includes a plurality of unit structures 18 each including a polarization beam splitter 14 including a polarization separation film 12 and a reflection mirror 16 including a polarization separation film 12 that functions as a reflection film. It has an aligned repeating structure. Further, in the illustrated example, half-wave plates 20 (FIG. 12) are regularly arranged on the output side end face of the reflection mirror 16.

  Then, the natural light L irradiated to the incident side end face of the polarization beam splitter array 10 enters the polarization beam splitter array 10 only from the portion of the polarization beam splitter 14. The natural light L is separated into P-polarized light passing through the polarization separation film 12 and S-polarized light reflected by the polarization separation film 12. Then, the P-polarized light passing through the polarization separation film 12 passes through the polarization beam splitter 14 as it is, and is emitted as P-polarized light from the exit side end face of the polarization beam splitter array 10. On the other hand, the S-polarized light reflected by the polarization separation film 12 is reflected again by the polarization separation film 12 in a direction parallel to the P-polarized light, and then passes through the half-wave plate 20 to be P-polarized light. It is converted into light. Therefore, when the natural light L passes through the polarizing beam splitter array 10, the natural light L is incident from only the portion of the polarizing beam splitter 14 of the unit structure 18, but all of the unit structure 18 is emitted at the time of emission. The polarized beam splitter 14 and the reflection mirror 16 constituting the unit structure 18 are inseparably integrated with each other, and are emitted in the state of being polarized into the same polarized light (P-polarized light in the illustrated example). is there. By using the polarization beam splitter array 10 in combination with the integrator optical system described above to constitute an illumination device, it is possible to increase the utilization efficiency of the light source light in the liquid crystal light valve (see, for example, Patent Document 1).

  Projection-type high-definition television (HDTV) systems and video projectors use a lamp with a large amount of light as the light source so that the brightness of the image can be adjusted according to the usage environment. A diaphragm device for reducing the amount of light is provided (for example, see Patent Document 2). As shown in FIG. 13, the diaphragm device 22 is adjacent to the fixed light-shielding plate 24 and a plurality of strip-shaped fixed light-shielding plates 24 that cover the incident side end face of the reflection mirror 16 that constitutes the polarization beam splitter array 10. In this manner, the movable light shielding plate 26 is slidably arranged. A slit-like light transmission portion 28 having the same width as the width B of the polarization beam splitter 14 is formed on the movable light shielding plate 26.

  Then, as shown in FIG. 13, the diaphragm device 22 is in an open state when the light transmitting portion 28 of the movable light shielding plate 26 coincides with the polarization beam splitter 14. Further, as shown in FIG. 14, by sliding the movable light shielding plate 26, the overlapping region between the light transmitting portion 28 and the fixed light shielding plate 24 increases, and the polarization beam splitter 14 is gradually moved by the movable light shielding plate 26. Covered with light, the light transmission area decreases. Then, as shown in FIG. 15, when the movable light shielding plate 26 is slid to a position where the polarization beam splitter 14 is completely covered, the diaphragm device 22 is fully closed.

JP-A-8-304739 JP 2003-207850 A

  As described above, according to the present invention, in an illuminating device having both the characteristics of an integrator optical system and a polarizing optical system, the occurrence of illuminance unevenness, color unevenness, and flicker is suppressed regardless of the aperture value of the stop device, and symmetry. It is possible to project a high-quality image by obtaining a good illumination light. Further, the light quantity adjustment by the diaphragm device can be performed at a higher speed. Further, the contrast of the image can be improved by changing the F number as required. Further, the “standby mode” can be provided by fully moving the movable light shielding plate. Furthermore, the present invention provides a high-performance and high-performance projection display device using such an illumination device.

(Aspect of the Invention)
The following aspects of the present invention exemplify the configuration of the present invention, and will be described separately for easy understanding of various configurations of the present invention. Each section does not limit the technical scope of the present invention, and some of the components of each section are replaced, deleted, or further while referring to the best mode for carrying out the invention. Those to which the above components are added can also be included in the technical scope of the present invention.

(1) A light source, a lens array configured by aligning a plurality of unit lenses, a polarizing beam splitter array having a repeating structure in which a unit structure including a polarizing beam splitter and a reflecting mirror is aligned, and a diaphragm device Comprising
The diaphragm device includes two movable light shielding plates arranged to be slidable with each other, and a driving means for sliding the two movable light shielding plates,
Each of the two movable light-shielding plates has a pitch that is the same or substantially the same as the pitch of the repeating structure of the polarization beam splitter array, and a longitudinal direction coincides with the longitudinal direction of the polarization beam splitter. Slit-shaped light transmission part is formed,
The driving means is based on the diaphragm opening state where the incident side end face of the polarization beam splitter of the unit structure and the transmitted light portions of the two movable light shielding plates are all coincident or substantially coincident with each other. A polarized light illumination device comprising: a drive mechanism capable of sliding the movable light shielding plate by the same distance at the same time in parallel to the alignment direction of the unit structures and in opposite directions.

In the polarization illumination device described in this section, in the open aperture state in which the incident side end face of the polarization beam splitter of the unit structure and the transmitted light portions of the two movable light shielding plates all coincide or substantially coincide, The opening area of the slit-like opening constituted by the transmitted light portion of the movable light shielding plate is maximized. Then, with the aperture open state as a base point, the two movable light shielding plates are slid and driven by the same distance in the opposite direction to each other in parallel with the alignment direction of the unit structures by the driving means. Then, the area of the polarization beam splitter that is shielded by the portions other than the transmitted light portion (the light shielding portion) of the two movable light shielding plates increases uniformly from both sides in the width direction (the opening area decreases equally). During this time, the center position in the width direction of the slit-shaped opening constituted by the transmitted light portions of the two movable light shielding plates does not move, and the center axis of the slit-shaped opening and the center axis of each polarization beam splitter The position is always constant regardless of the opening of the expansion device. Therefore, it is possible to always obtain a projection light having a good symmetry regardless of the opening degree of the aperture device.
Further, since the two movable light-shielding plates are slid and driven by the same distance in the opposite direction to each other at the same time by the driving means, the transmitted light of the two movable light-shielding plates is transmitted. The area change rate of the polarization beam splitter that is shielded by the portion other than the portion (the light shielding portion) is twice the rate of change when only one movable light shielding plate is slid.

In this section, the plurality of slit-shaped light transmitting portions formed on each of the two movable light shielding plates have the same or substantially the same pitch as that of the repeating structure of the polarization beam splitter array, and the longitudinal direction. Is formed so as to coincide with the longitudinal direction of the polarizing beam splitter. The reason for including “substantially the same pitch” in the present description is that the two pitches do not necessarily coincide with each other as necessary. It is clarified that it includes the case of giving a deviation. The amount of deviation is set as appropriate in consideration of optimization of optical characteristics.
In addition, when the aperture of the aperture stop is in the open state, the incident side end face of the polarization beam splitter of the unit structure and the transmitted light portions of the two movable light shielding plates are all coincident or substantially coincide with each other. The reason for including “matching” is to clarify that the above-described elements are included in some cases without being completely matched if necessary. The amount of deviation is set as appropriate in consideration of optimization of optical characteristics.

(2) The width A of the unit lens constituting the lens array and the width B of the polarization beam splitter constituting the polarizing beam splitter array have a relationship of A≈2B, and the light transmitting portion of the movable light shielding plate The polarization illumination device is configured such that the width C of the light-shielding portion and the width D of the light-shielding portion satisfy the relationships of C + D = 2B, B <C, and D <C (claim 2).
The polarization illumination device described in this section has high light utilization efficiency by satisfying each of the above relationships, and can always obtain projection light with good symmetry regardless of the aperture of the diaphragm device. It is. In this description, the reason that “A≈2B” is clarified to include a case where a slight dimensional difference is included without completely matching A and 2B. Such a dimensional difference is appropriately set in consideration of optimization of optical characteristics.

(3) A widening light-shielding portion having a width equal to or greater than the width of the unit structure is formed in a region on the outer side in the sliding direction of the movable light-shielding plate from the region where the light transmission portion is formed, and the driving unit Includes a first driving mode that gives a sliding amount equal to or less than a width of the polarizing beam splitter of the unit structure to the movable light shielding plate, and a second driving mode that gives an arbitrary sliding amount exceeding the width of the unit structure. A polarization illumination device comprising:
In the polarization illumination device described in this section, a widened light-shielding portion having a width equal to or greater than the width of the unit structure is formed in a region on the outer side in the sliding direction of the movable light-shielding plate than the region where the light transmission portion is formed. Therefore, when the two movable light shielding plates are slid in the second drive mode by the driving means, the sliding amount increases and the movable light shielding plate is positioned at the end of the plurality of transmitted light portions of one movable light shielding plate. In order from the transmitted light portion, the light is covered with the widened light shielding portion of the other movable light shielding plate. Then, it is possible to match the remaining part of the transmitted light parts that are not covered. In such a state, the unit structure composed of the polarization beam splitter and the reflection mirror, which are inseparably integrated as described above, is covered by the widened light-shielding part, and the transmitted light parts of the two movable light-shielding plates are covered. As a result, the amount of natural light passing through the polarization beam splitter array is reduced, so that the aperture value (F number) in the aperture open state of the aperture device is increased. Can do. The aperture value can be freely adjusted by sliding the two movable light-shielding plates in the first drive mode by the drive means in a state where the number of slit-like openings is reduced. Therefore, high contrast can be easily obtained as necessary.

(4) The length of the movable light-shielding plate in the longitudinal direction of the light transmission portion is formed so as to be shorter from the center of the region where the light transmission portion is formed toward the outside in the sliding direction. Polarized illumination device (Claim 4).
The polarized light illumination device described in this section is formed such that the length of the light transmitting portion in the longitudinal direction is shorter as it is located on the outer side in the sliding direction from the center of the region where the light transmitting portion is formed. Therefore, the slit-shaped opening constituted by the transmitted light portions of the two movable light shielding plates forms a circular opening as a whole while alternately including the light shielding portions, and a well-balanced projection light can be obtained.

(5) The polarization illumination device (claim 5), wherein the movable light shielding plate is disposed between the lens array and the polarization beam splitter array.
Since the polarizing beam splitter array is usually assembled using an optical adhesive (such as an ultraviolet curing type), it is difficult to obtain sufficient heat resistance. Therefore, it is common to provide a blower for air-cooling both main surfaces (light incident side end surface and light exit side end surface) of the polarizing beam splitter array. Therefore, the polarization illumination device described in this section effectively uses this blower to simultaneously remove heat from the movable light shielding plate by the cooling air for the polarization beam splitter array, and the polarization beam splitter array and the movable light shielding plate. Temperature rise can be prevented. In particular, when the two movable light shielding plates are closed, the movable light shielding plates are illuminated with more light, but their temperature rise is effectively suppressed, so that the lens array and the polarizing beam splitter array are It is possible to avoid a temperature rise in the space.

  (6) A light modulation element that modulates linearly polarized light whose light amount is adjusted by the polarized illumination device according to the above (1) to (5) in response to a video signal, and a modulated light obtained by the light modulation element. A projection display device comprising projection means (claim 6).

  Since the present invention is configured as described above, the light is narrowed down in a light quantity diaphragming device that can be used in a projection-type high-definition television (HDTV) system or a video projector and that mechanically blocks the light of the lamp. Therefore, the operation of the movable light shielding plate can be performed at a higher speed. In addition, it is possible to obtain illumination light with good symmetry. In addition, it is possible to switch to a dimming mode in which the F number is variable without adding a special structure. Further, it is possible to switch to the “standby mode” in the fully closed state without adding a special structure or changing the size. Furthermore, it is possible to provide a high-function and high-performance projection display device using such an illumination device.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Here, parts that are the same as or correspond to those in the prior art are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 1 shows a projection display device 32 including a polarized illumination device 30 according to an embodiment of the present invention. The polarization illumination device 30 includes a light source unit 38 including a light source lamp 34 and a reflector 36, a first lens array 40, a second lens array 42, a polarization beam splitter array 10, and a field lens 44. ing. Further, a diaphragm device 46 is disposed between the second lens array 42 and the polarization beam splitter array 10. The diaphragm device 46 includes two movable light shielding plates 26 and driving means 52 including an electric motor 48 and a motor driving circuit 50.

The projection display device 32 includes three liquid crystal light valves LQR, LQB, and LQG that are independent in order to individually correspond to the three primary colors as light modulation elements that modulate in response to the video signal SII. In addition, a so-called three-plate type liquid crystal projector including a plurality of mirrors, lenses, and prisms as projection means for modulated light obtained by these light modulation elements is presented. Specifically, the single linearly polarized light emitted from the field lens 44 of the polarization illumination device 30 is applied to the first dichroic mirror 54, and only the red component passes through the first dichroic mirror 54, Are reflected by the mirror 56 and irradiated onto the liquid crystal light valve LQR. Further, the light including the blue component and the green component reflected by the first dichroic mirror 54 is reflected by the second dichroic mirror 58 and irradiated to the liquid crystal light valve LQG. Further, the light including only the blue component that has passed through the second dichroic mirror 58 is irradiated to the liquid crystal light valve LQB via the lens 60, the second mirror 62, the lens 64, the third mirror 66, and the lens 68. Is done. The signal processing means 72 configured by an electronic computer or the like receives the red drive signal RD, the blue drive signal BD, and the green drive signal GD processed from the video signal SII, and modulates the irradiated light according to each color. Convert to light. Since the liquid crystal light valves LQR, LQB, and LQG all face the dichroic prism 70, the modulated lights of the respective colors emitted from the liquid crystal light valves LQR, LQB, and LQG are combined by the dichroic prism 70, The image is projected onto the screen 76 via the projection lens 74.
The polarization illumination device 30 uses a reflective liquid crystal such as LCOS (Liquid crystal on silicon) or a liquid crystal other than the liquid crystal such as a DMD (Digital mirror device) as a light modulation element that modulates in response to the video signal SII. Of course, the present invention can also be applied to a projection display device.

  Next, the diaphragm device 46 of the polarization illumination device 30 will be described in detail with reference to FIGS. 2 to 10. As shown in FIG. 2, the diaphragm device 46 includes a plate-shaped diaphragm unit base 78 and two movable light shielding plates 26 </ b> A and 26 </ b> B arranged on one side of the diaphragm unit base 78. In the illustrated example, the aperture unit base 78 is a resin molded product, and the two movable light shielding plates 26A and 26B are both formed of a metal plate. The movable light shielding plates 26 </ b> A and 26 </ b> B are arranged parallel to the diaphragm unit base 78 and slidable with respect to each other. Further, as shown in FIGS. 2A and 4, the aperture unit base 78 is formed with an opening 78a for allowing light to pass therethrough. Further, as shown in FIG. 3, the polarization beam splitter array 10 (see FIGS. 11 and 12) is repeated in the region of the two movable light shielding plates 26 </ b> A and 26 </ b> B that faces the opening 78 a of the aperture unit base 78. A plurality of slit-shaped light transmissions having the same or substantially the same pitch PI as the structure, and the longitudinal direction (Z direction) coincides with the longitudinal direction of the polarizing beam splitter 14 (see FIGS. 11 and 12). Portions 80 and 82 are formed. The lengths of the light transmitting portions 80 and 82 in the longitudinal direction are formed to be shorter as they are located on the outer side in the sliding direction (X direction) from the center of the region where the light transmitting portions are formed. In the illustrated example, the transmitted light portions 80C, 80D, 82C, and 82D located at the center of the region where the light transmissive portion is formed are the longest, and the transmitted light portions 80B, 80E, 82B, and 82E located outside these regions are Following this, the transmitted light portions 80A, 80F, 82A, and 82F that are long and located on the outermost side are formed shortest.

  Further, four pins 84 are provided upright on the aperture unit base 78, and elongated holes 86 and 88 for engaging the pins 84 are formed in each of the movable light shielding plates 26A and 26B. The elongated holes 86 and 88 extend in parallel to the sliding direction of the movable light shielding plates 26A and 26B with respect to the aperture unit base 78. Further, the lengths of the long holes 86 and 88 are required in the second driving mode that gives an arbitrary sliding amount exceeding twice the width of the polarizing beam splitter 14 (FIGS. 11 and 12), which will be described later. Each of the movable light shielding plates 26A and 26B has a length corresponding to the slide stroke.

An electric motor 48 (FIG. 2B) is provided on the surface of the diaphragm unit base 78 opposite to the one surface where the two movable light shielding plates 26A and 26B are disposed. The rotating shaft 48a of the electric motor 48 passes through the aperture unit base 78 and protrudes to one side where the two movable light shielding plates 26A and 26B are disposed. And the arm 90 which drives each movable light-shielding plate 26A, 26B is being fixed to the rotating shaft 48a.
At both ends of the arm 90, there are provided two drive pins 92, 94 that engage with each of the two movable light shielding plates 26A, 26B. The drive pins 92 and 94 draw an arcuate movement locus at opposite positions around the rotation shaft 48a of the electric motor 48 when the arm 90 is rotationally driven by the electric motor 48.

  Further, only the driving force in the direction parallel to the sliding direction (X direction in FIG. 3) of the movable light shielding plates 26A and 26B is taken out from the arcuate movement trajectories of the drive pins 92 and 94 to the movable light shielding plates 26A and 26B. In order to cancel the driving force in the direction orthogonal to the sliding direction (the Z direction in FIG. 3), the driving pins 92 and 94 have substantially the same width as the diameter and are orthogonal to the sliding direction of the movable light shielding plates 26A and 26B. Engagement holes 96, 98 extending in the direction are formed. Therefore, by rotating the arm 90 within a certain angle range by the electric motor 48, the movable light shielding plates 26A and 26B are parallel to the unit structure alignment direction (X direction) and in opposite directions to each other. At the same time, a drive mechanism that can be slid by the same distance is configured. In addition, each constituent element is set so that the diaphragm opening state where the incident side end face of the polarization beam splitter 14 and the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B are all coincident or substantially coincident is the base point. Is positioned.

In the illustrated example, the tongue portions 100 and 102 are projected from the movable light shielding plates 26A and 26B, and the engagement holes 96 and 98 are formed in the tongue portions 100 and 102, whereby the movable light shielding plates 26A and 26B overlap. Regardless of the increase / decrease, interference between the drive pins 92 and 94 and the movable light shielding plates 26A and 26B can be prevented.
In the embodiment of the present invention, the electric motor 48 is provided on the surface of the diaphragm unit base 78 opposite to the one surface where the two movable light shielding plates 26A and 26B are disposed. Accordingly, both can be provided on the same surface side of the aperture unit base 78. In the embodiment of the present invention, the two movable light shielding plates 26A and 26B are arranged on one side of the diaphragm unit base 78, but the two movable light shielding plates are sandwiched between the diaphragm unit base 78. 26A and 26B may be arranged.

Further, the two movable light shielding plates 26A and 26B have the following dimensional characteristics.
In the polarization illumination device 30 according to the embodiment of the present invention, the second lens array 42, the diaphragm device 46, and the polarization beam splitter array 10 are arranged as shown in FIG. Here, the width A of the unit lens 104 constituting the lens array 42 and the width B of the polarization beam splitter 14 constituting the polarization beam splitter array 10 are in a relationship of A≈2B, and the movable light shielding plates 26A and 26B are provided. The width C of each of the light transmitting portions 80A to 80F and 82A to 82F and the width D of the light shielding portion sandwiched between the light transmitting portions satisfy the relationships of C + D = 2B, B <C, and D <C. It is configured. The light transmission widths C are all the same, and the light shielding portions D sandwiched between the light transmission portions are all the same.

  Furthermore, as shown in FIG. 3, the polarizing beam splitter 14 (FIG. 11, FIG. Widened light-shielding portions 106 and 108 having a width Q equal to or greater than twice the width B of FIG. 12) are formed. In the illustrated example, the width Q of the widened light-shielding portions 106 and 108 is Q> (C + D) = 2B. In FIG. 3, the widened light-shielding portion 106 is provided at the left end of the movable light-shielding plate 26A and the widened light-shielding portion 108 is provided at the right end of the movable light-shielding plate 26B. .

  The signal processing means 72 according to the embodiment of the present invention receives the video signal SII and outputs a necessary drive signal to the motor drive circuit 50 as shown in FIG. This video signal SII is used for automatically analyzing an image being projected by the signal processing means 72 and automatically setting an aperture value appropriately. It is also possible to output necessary drive signals to the motor drive circuit 50 when automatically setting according to the video genre, or based on additional information transmitted together with the video signal SII. In particular, since various kinds of additional information can be easily sent in a digital video signal, when the information about the brightness of the video is written on the format of the digital video signal, the additional information can be used. .

  Specifically, the signal processing means 72 receives the video signal SII, and appropriately selects the following “normal mode” and “squeezed mode” to control the driving means 52. Here, the “normal mode” is a mode (first driving mode) in which the driving unit 52 gives the sliding amount within the same range as the width B of the polarizing beam splitter 14 to the two movable light shielding plates 26A and 26B. is there. In the “narrowing mode”, the driving means 52 is twice the width B of the polarizing beam splitter 14 (corresponding to the width of the unit structure 18 (FIG. 11)) with respect to the two movable light shielding plates 26A and 26B. This is a mode (second drive mode) that gives an arbitrary slide amount exceeding.

  The signal processing means 72 according to the embodiment of the present invention receives an input signal SIP from the position sensors of the two movable light shielding plates 26A and 26B as shown in FIG. It is also possible to perform feedback control such as outputting a necessary drive signal to the drive circuit 50. Further, instead of the input signal SIP from the position sensor, the light quantity sensor detects the light quantity of light passing through the slit-shaped opening A constituted by the transmitted light portions 80 and 82, and the two movable light shielding plates 26A. , 26B can be feedback controlled. Furthermore, it is possible to output a necessary drive signal to the motor drive circuit 50 based on the mode selection signal SIM obtained by the user arbitrarily setting the mode according to the content of the image to be projected.

Next, the operation of the diaphragm device 46 of the polarization illumination device 30 according to the embodiment of the present invention will be described.
2 and 5 show a state where the diaphragm is opened in the “normal mode”. In this state, the incident side end face of the polarization beam splitter 14 and the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B all coincide. In addition, since the entire surfaces of the transmitted light portions 80 and 82 coincide with the incident side end face of the polarization beam splitter 14, the slit formed by the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B. The opening area OA of the shaped opening is maximized. In consideration of optimization of optical characteristics, the polarization beam splitter 14 and the transmitted light portions 80 and 82 may be slightly shifted for each slit-shaped opening.

  6 and 7 show the narrowed-down state in the “normal mode”. In this narrowed state, the arm 90 is rotationally driven within a range of a certain angle, so that each movable light shielding plate 26A, 26B is parallel to the alignment direction of the unit structures and opposite to each other at the same time by the same distance. It is obtained by sliding. In the “normal mode”, the sliding amount of each of the movable light shielding plates 26A and 26B does not exceed the width B (FIG. 4) of the polarizing beam splitter 14. Accordingly, each incident-side end face of the polarization beam splitter 14 and each of the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B are all kept in the same state, and the two movable light shielding plates 26A and 26A, The opening area OA of the slit-like opening constituted by the transmitted light portions 80 and 82 of 26B decreases for each opening. At this time, the positional relationship between the central axis in the width direction of the polarizing beam splitter 14 and the central axis in the width direction of the slit-shaped opening constituted by the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B is It is always constant and never changes. Finally, the opening area OA of each slit-like opening becomes zero (this state is referred to as “standby mode” in this description).

FIGS. 8 and 9 show the open state in the “narrowing mode”. In this narrowing mode, the arm 90 is rotationally driven at a larger angle than the narrowing state in the normal mode, so that each movable light shielding plate 26A, 26B is simultaneously parallel to the unit structure alignment direction and in the opposite direction. It is obtained by sliding the same distance. Accordingly, in the “narrowing mode”, the sliding amount of each of the movable light shielding plates 26A and 26B exceeds twice the width B (FIG. 4) of the polarization beam splitter 14, and the light transmitting portion 82 of the movable light shielding plate 26B is movable light shielding. The light shielding portion 106 of the movable light shielding plate 26B is covered with the wide light shielding portion 108 of the movable light shielding plate 26B.
In the example of FIG. 9A, the transmitted light portions 80A and 82C, the transmitted light portions 80B and 82D, the transmitted light portions 80C and 82E, and the transmitted light portions 80D and 82F are in agreement, and are formed by these transmitted light portions. Each of the slit-shaped openings coincides with the incident side end face of a part of the polarization beam splitter 14. Therefore, the opening area OA of the slit-like opening constituted by the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B is compared with the aperture opening state in the “normal mode” (FIG. 5B). Decrease.

FIG. 10 shows a narrowing state in the “narrowing mode”. In this narrowed state, the movable light shielding plates 26A and 26B are further rotated by driving the arm 90 within a certain angle range from the full aperture state in the “squeezed mode” shown in FIGS. This is obtained by sliding the unit structures in parallel with the alignment direction and in the opposite directions at the same time by the same distance.
As in the narrowed-down state in the “normal mode”, the opening area OA of the slit-like opening formed by the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B decreases for each opening. At this time, the positional relationship between the central axis in the width direction of the polarizing beam splitter 14 and the central axis in the width direction of the slit-shaped opening formed by the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B is It is always constant and never changes. Finally, the opening area OA of each slit-like opening becomes zero (“standby mode”).

The effects obtained by the embodiment of the present invention having the above-described configuration are as follows. First, in the polarization illumination device described in this section, the aperture opening state in which the incident-side end face of the polarization beam splitter 14 and the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B all coincide or substantially coincide. In FIGS. 2 and 5, the opening area OA of the slit-like opening constituted by the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B is maximized. Then, with this aperture open state as a base point, the driving means 52 causes the two movable light shielding plates 26A and 26B to be parallel to the alignment direction (X direction) of the unit structures 18 (FIG. 11) of the polarization beam splitter array 10. At the same time, they are slid by the same distance in opposite directions. Then, the area of each polarization beam splitter 14 that is shielded by the portions other than the transmitted light portion (the light shielding portion) of the two movable light shielding plates 26A and 26B increases uniformly from both sides in the width direction (the opening area is reduced). Evenly). During this time, the center position in the width direction of the slit-shaped opening constituted by the transmitted light portions 80 and 82 of the two movable light-shielding plates 26A and 26B does not move, and the central axis of the slit-shaped opening and the polarization beam The position of the central axis of the splitter 14 is always constant regardless of the opening degree of the expansion device 46. Therefore, it is possible to always obtain projection light having a good symmetry regardless of the opening degree of the diaphragm device 46.
Further, in the case of the diaphragm device of this configuration, the opening area OA can be made completely zero without requiring a strict size system at the time of production. Therefore, it is possible to easily cope with the “standby mode” that requires full closure without adding any new parts.

  Further, since the two movable light-shielding plates 26A and 26B are slid and driven by the same distance in the opposite direction to each other at the same time by the driving means 52 in parallel with the alignment direction (X direction) of the unit structures 18. The area change rate of the polarization beam splitter 14 that is shielded by the portions other than the transmitted light portion (the light shielding portion) of the single movable light shielding plates 26A and 26B is twice the rate of change when only one movable light shielding plate is slid. It becomes. Therefore, the light amount adjustment can be performed at high speed.

  In addition, as shown in FIG. 4, the polarization illumination device 30 according to the embodiment of the present invention includes the width A of the unit lens constituting the second lens array 42 and the polarization beam constituting the polarization beam splitter array 10. The width B of the splitter 14 is in a relation of A≈2B, and the width C of the light transmission part and the width D of the light shielding part of the two movable light shielding plates 26A, 26B are C + D = 2B, B <C, It is configured to satisfy each relationship of D <C. By satisfying the above relationships, it is possible to always obtain projection light with good symmetry regardless of the opening degree of the diaphragm 46.

  Widened light-shielding portions 106 and 108 having a width equal to or greater than the width of the unit structure are formed on the outer sides of the two movable light-shielding plates 26A and 26B in the sliding direction from the region where the light transmission portions 80 and 82 are formed. Thus, when the two movable light shielding plates 26A and 26B are slid in the second driving mode (squeezing mode) by the driving means 52, the sliding amount increases and a plurality of transmissions of one movable light shielding plate occur. Among the light parts, the light is sequentially covered from the transmitted light part located at the end (80F → 80E → 80D..., 82A → 82B → 82C...), And is covered by the widened light shielding parts 106 and 108 of the other movable light shielding plate. To go. Then, it is possible to match the remaining part of the transmitted light parts that are not covered. In such a state, the unit structure 18 composed of the polarization beam splitter 14 and the reflection mirror 16 that are inseparably integrated with each other is covered by the widened light-shielding portions 106 and 108, and each unit of the unit structure 18 is concealed. , 26B, the number of slit-like openings formed by the transmitted light portions 80 and 82 is reduced, and as a result, the amount of natural light passing through the polarization beam splitter array is reduced. The value (F number) can be increased. The aperture value can be freely adjusted by sliding the two movable light-shielding plates in the first drive mode by the drive means in a state where the number of slit-shaped openings is reduced. Contrast can be easily obtained.

  Further, as shown in FIG. 3, the length of the light transmitting portions 80 and 82 in the longitudinal direction (Z direction) is located outside the center of the area where the light transmitting portions 80 and 82 are formed in the sliding direction. Therefore, the slit-shaped opening formed by the transmitted light portions 80 and 82 of the two movable light shielding plates 26A and 26B is formed in a circular shape as a whole while alternately including the light shielding portions. An opening is formed, and a well-balanced projection light can be obtained.

The two movable light-shielding plates 26A and 26B are disposed between the second lens array 42 and the polarization beam splitter array 10. The polarization beam splitter array 10 is usually made of an optical adhesive (ultraviolet light). For example, it is difficult to obtain sufficient heat resistance. Therefore, the polarization illumination device 30 generally includes a blower for air-cooling both main surfaces (light incident side end surface and light emission side end surface) of the polarization beam splitter array 10.
In the embodiment of the present invention, the air blower is effectively used to simultaneously remove heat from the two movable light shielding plates 26A and 26B by the cooling cold air for the polarizing beam splitter array 10, and the polarizing beam splitter array 10 and The temperature rise of the two movable light shielding plates 26A and 26B can be prevented. In particular, when the two movable light-shielding plates 26A and 26B are closed, the movable light-shielding plates 26A and 26B are illuminated with more light, but since their temperature rise is effectively suppressed, the second lens array 42 and The temperature rise in the space between the polarizing beam splitter array 10 can be avoided.

  Therefore, as shown in FIG. 1, the polarization illumination device 30 according to the embodiment of the present invention, the light modulation elements (liquid crystal light valves LQR, LQB, LQG) that modulate in response to the video signal SIP, the light modulation Projection means for modulated light obtained by the elements (first dichroic mirror 54, first mirror 56, second dichroic mirror 58, lens 60, second mirror 62, lens 64, third mirror 66, lens 68 The projection display device 32 including the dichroic prism 70 and the projection lens 74) can suppress the generation of illuminance unevenness, color unevenness, and flicker, and can display a higher quality image. In addition, the contrast of the image can be improved as necessary.

It is the schematic of a projection display apparatus provided with the polarization illumination apparatus which concerns on embodiment of this invention. FIGS. 2A and 2B show a diaphragm device of the polarization illumination device shown in FIG. 1, in which FIG. 1A is a plan view showing a state in which the diaphragm is opened in “normal mode”, and FIG. FIG. 3 is a plan view of two movable light shielding plates of the diaphragm device shown in FIG. 2, and (a) and (b) show the respective light shielding plates. It is sectional drawing which expanded and showed the principal part of the polarization illuminating device shown by FIG. 1A and 1B show a state where the diaphragm is opened in the “normal mode” of the diaphragm device of the polarization illumination apparatus shown in FIG. 1, where FIG. 1A is a cross-sectional view of the main part, and FIG. It is a top view which shows the opening area of the slit-shaped opening comprised by these. FIGS. 2A and 2B show a diaphragm device of the polarization illumination device shown in FIG. 1, in which FIG. 1A is a plan view of a narrowed state in “normal mode”, and FIG. FIG. 1 shows a narrowed state in the “normal mode” of the diaphragm device of the polarization illumination apparatus shown in FIG. 1, (a) is a cross-sectional view of the main part, and (b) is a transmitted light part of two movable light shielding plates. It is a top view which shows the opening area of the slit-shaped opening comprised. FIGS. 2A and 2B show a diaphragm device of the polarization illumination device shown in FIG. 1, in which FIG. 1A and 1B show a state where a diaphragm is opened in a “squeezing mode” of the diaphragm device of the polarization illumination apparatus shown in FIG. 1, where FIG. 1A is a cross-sectional view of the main part, and FIG. It is a top view which shows the opening area of the slit-shaped opening comprised by these. FIG. 1 shows a narrowed state in the “squeezed mode” of the diaphragm device of the polarization illumination device shown in FIG. 1, (a) is a cross-sectional view of the main part, and (b) is a transmitted light part of two movable light shielding plates. It is a top view which shows the opening area of the slit-shaped opening comprised. It is a perspective view of a polarization beam splitter array. FIG. 12 is a side view of the polarization beam splitter array shown in FIG. 11. It is a figure which shows the aperture_diaphragm | restriction apparatus of the conventional polarized light illuminating device, (a) is a perspective view of a diaphragm open state, (b) is an ipsilateral side view. It is a figure which shows the diaphragm | throttle device of the conventional polarized light illuminating device, (a) is a perspective view of a narrowed-down state, (b) is a side view on the same side. It is a figure which shows the aperture_diaphragm | restriction apparatus of the conventional polarized light illuminating device, (a) is a perspective view of a closed state, (b) is an ipsilateral side view.

Explanation of symbols

  10: Polarization beam splitter array, 12: Polarization separation film, 14: Polarization beam splitter, 18: Unit structure, 22: Aperture device, 26, 26A, 26B: Movable light shielding plate, 28: Light transmission part, 30: Polarized illumination Device: 32: projection display device, 38: light source unit, 40: first lens array, 42: second lens array, 46: diaphragm device, 52: drive means, 72: signal processing means, 80, 82: transmission Light part, 104: Unit lens, 106, 108: Area outside slide direction with respect to area where light transmission part is formed

Claims (6)

A light source, a lens array configured by aligning a plurality of unit lenses, a polarization beam splitter array having a repeating structure in which a unit structure including a polarization beam splitter and a reflecting mirror is aligned, and an aperture device ,
The diaphragm device includes two movable light shielding plates arranged to be slidable with each other, and a driving means for sliding the two movable light shielding plates,
Each of the two movable light-shielding plates has a pitch that is the same or substantially the same as the pitch of the repeating structure of the polarization beam splitter array, and a longitudinal direction coincides with the longitudinal direction of the polarization beam splitter. Slit-shaped light transmission part is formed,
The driving means is based on the diaphragm opening state where the incident side end face of the polarization beam splitter of the unit structure and the transmitted light portions of the two movable light shielding plates are all coincident or substantially coincident with each other. A polarized light illumination device comprising: a drive mechanism capable of sliding the movable light shielding plate by the same distance at the same time in parallel to the alignment direction of the unit structures and in opposite directions. The width A of the unit lens constituting the lens array and the width B of the polarization beam splitter constituting the polarizing beam splitter array are in a relationship of A≈2B, and the width C of the light transmitting portion of the movable light shielding plate The polarization illumination device according to claim 1, wherein the light shielding portion and the width D of the light shielding portion satisfy the following relationships: C + D = 2B, B <C, D <C. An enlarged light-shielding portion having a width equal to or greater than the width of the unit structure is formed in a region outside the movable light-shielding plate in the sliding direction outside the region where the light transmission portion is formed,
The drive means has a first drive mode that gives the movable light shielding plate a slide amount that is equal to or less than the width of the polarization beam splitter of the unit structure, and an arbitrary slide amount that exceeds the width of the unit structure. The polarized illumination device according to claim 1, further comprising: a second driving mode to be applied. The length of the movable light shielding plate in the longitudinal direction of the light transmitting portion is formed so as to be shorter from the center of the region where the light transmitting portion is formed toward the outside in the sliding direction. The polarized light illumination device according to any one of claims 1 to 3. 5. The polarization illumination device according to claim 1, wherein the movable light shielding plate is disposed between the lens array and the polarization beam splitter array. 6. A light modulation element that modulates linearly polarized light whose light amount has been adjusted by the polarization illumination device according to claim 1 in response to a video signal, and a projection unit for modulating light obtained by the light modulation element. Projection display device.

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