JP4738782B2 - Illumination optical system and projection image display apparatus having the same - Google Patents

Description

  The present invention generally relates to a projection type image display apparatus such as a liquid crystal projector using an image display element, and more particularly to an illumination optical system that illuminates an image display element and a projection type image display apparatus having the same.

With the recent spread of projection type image display devices such as liquid crystal projectors, the image quality of projection type image display devices is increasingly required. Recent polarization-type liquid crystal projectors modulate the image of illumination light from an illumination optical system with a reflective liquid crystal display element (or reflective liquid crystal panel) . Then , the modulated light is detected by a polarizing beam splitter (hereinafter referred to as “PBS”) and guided to a projection optical system (for example, see Patent Document 1). . In such a projection type image display apparatus, it is important that the image projected on the screen has a brightness that is nearly uniform over the entire screen.

  Therefore, Patent Document 1 adopts a so-called double integrator configuration in which a pair of fly-eye lenses in which lens elements are arranged two-dimensionally (or in a matrix) are arranged in the rear stage of the lamp in the illumination optical system. With such a double integrator configuration, the illuminance distribution of the illumination light from the light source can be made substantially two-dimensionally uniform, and the subsequent reflective liquid crystal display element can be illuminated with the uniform illuminance distribution.

There exists patent document 2 as another prior art.
JP 2004-12864 A JP-A-6-75200

  In order to further improve the color unevenness and contrast due to the recent demand for higher image quality, the present inventor examined the use of a one-dimensional integrator instead of a two-dimensional integrator as in Patent Document 2. With such a configuration, it is possible to reduce color unevenness due to the thin film component in order to suppress the angular distribution in the cross section direction of the light beam, and to improve the contrast.

However, in Patent Document 2, the illuminance distribution on the cross section where the one-dimensional integrator does not have refractive power is not uniformized by the superimposed illumination of the lens cell, and therefore the illuminance distribution on the image display element is deteriorated in the light emission distribution of the lamp, etc. It is greatly influenced by abnormally.

  For example, as shown in FIG. 11A, when there is a lamp 1 in which the light source 2 is at the focal position of the reflector 4, the emission distribution viewed from the direction A in FIG. ), And the light quantity distribution along the X-axis has two substantially symmetrical mountain shapes as shown in FIG. The reason for the two mountain shapes is that the light source 2 itself becomes a shadow of the light from the reflector 4. Further, the surface illuminance distribution along the X axis on the image display element is as shown in FIG.

  However, if the light source 2 is displaced from the focal position of the reflector 4 due to a manufacturing error or a change with time, or the light source 2 is deteriorated, the state shown in FIGS. ). Here, FIG. 12A shows the light emission distribution when the light source 2 is shifted from the focal position of the reflector 4 to the surface minus side perpendicular to the optical axis, and FIG. 12B is along the X axis in that case. FIG. 12C shows the surface illuminance distribution along the X axis on the image display element. As a result, as shown in FIG. 12C, illuminance unevenness occurs on the image display element and the projected screen.

  Therefore, the present invention provides an illumination optical system capable of further improving image quality such as color unevenness and contrast improvement while maintaining uniform brightness on a projection screen, and a projection type image display apparatus having the same. For illustrative purposes.

An illumination optical system according to an aspect of the present invention receives a light from a light source unit, and includes a first integrator having a plurality of first cylindrical lenses arranged in a first direction substantially orthogonal to an optical axis, and the first integrator A second integrator having a plurality of second cylindrical lenses arranged in a direction parallel to the direction and corresponding to the first cylindrical lens and taking in individual light beams divided and condensed by the first integrator; the light passing through the integrator has a light collecting means to collect light, a illumination optical system for illuminating a target surface, said first direction, and when the optical axis and a direction perpendicular to the second direction, The condensing unit condenses light that has passed through the second integrator only in the second direction, and among the light beams collected by the condensing unit, the light emission distribution of the light source unit is in the second direction. Light shielding plate for shielding the light intensity high side optical part is Oite asymmetric, characterized in that it is arranged near the condensing position of the focusing means.

  Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  ADVANTAGE OF THE INVENTION According to this invention, the illumination optical system which can aim at the further image quality improvement in the state which maintained the uniform brightness in the to-be-projected screen, and a projection type image display apparatus having the same can be provided.

Hereinafter, an illumination optical system 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is a simplified optical path diagram of the illumination optical system 10. More specifically, FIG. 1A shows a yz section in which integrators 12 and 14 described later have power . FIG. 1B shows an xz cross section in which the integrators 12 and 14 have no power. The x axis represents the left and right, the y axis represents the up and down, the z axis represents the optical axis direction, and the origin of xy is the optical axis.

The illumination optical system 10, as shown in FIG. 1, Ru optics der for illuminating the image display element 40 as a surface to be illuminated by receiving the light from the lamp 1 (light source 2 and the reflector 4). The illumination optical system 10 includes a first integrator 12, a second integrator 14, a first light beam compression lens 16, a light shielding plate (or diaphragm) 20, a condenser lens 30, and a second light beam compression lens 32. The lamp 1 itself may or may not be a part of the illumination optical system 10.

  In the yz section, the white light emitted from the light source 2 is reflected by the reflector 4 and passes through the first integrator 12 and the second integrator 14. Thereafter, the light enters the image display element 40 through the light shielding plate 20 and the condenser lens 30. In the yz cross section, the first light beam compression lens 16 and the second light beam compression lens 32 have no refractive power and can be handled as a simple glass block. The first integrator 12 forms a plurality of light source images in the vicinity of the second integrator 14 based on the light flux from the light source 2. On the other hand, each lens cell of the first integrator 12 is conjugate with the image display element 40 that is an illuminated surface by the action of the second integrator 14 and the condenser lens 30, and each lens cell is superimposed by the condenser lens 30. An image is formed on the illumination surface.

In the xz cross section, the white light emitted from the light source 2 is reflected by the reflector 4 and travels toward the first integrator 12. In the xz section, the first integrator 12 and the second integrator 14 do not have refractive power and can be handled as a simple glass block. Thereafter, the illumination light is incident on the image display element 40 through the first light flux compression lens 16, the light shielding plate 20, the condenser lens 30, and the second light flux compression lens 32. The first luminous flux compression lens 16, the condenser lens 30, and the second luminous flux compression lens 32 constitute a substantially afocal system that compresses and emits parallel light at a constant pupil magnification in the xz cross section (first plane). Has been placed.

The light shielding plate 20 is disposed in the vicinity of the focal position of the first light flux compression lens 16, which is in the vicinity of the light condensing position in the direction orthogonal to the arrangement direction (Y direction) of the lens cells of the integrators 12 and 14 . When the focal length of the first beam compression lens 16 is f, the light shielding plate 20 is positioned a focal position of the first beam compression lens 16, the distance along the optical axis direction from the focal position within 0.3f (preferably 0. within 15f) is preferably arranged at the position of. Here, the focal position is a position away from the main plane of the first light beam compression lens 16 by the focal length of the first light beam compression lens 16 or the first light emission surface of the first light beam compression lens 16. This is a position separated by the focal length of the light beam compression lens 16. FIG. 2 shows an enlarged plan view of the light shielding plate 20. The light shielding plate 20 has an opening 22 and a light shielding part 24 as shown in FIG. The opening shape of the opening 22 is not limited to the shape shown in FIG. 2 as will be described later.

The operation of the light shielding plate 20 will be described in detail with reference to FIGS. In a system in which the light shielding plate 20 is not disposed, a right and left light amount difference is generated on the image display element 40 when the light source 2 is deviated from the focal position of the reflector 4 as shown in FIG . However , by installing the light shielding plate 20, it is possible to reduce and equalize the difference in the amount of light on the left and right from the state shown by the dotted line to the state shown by the solid line in FIG.

  This mechanism will be described with reference to FIGS. In the present embodiment, since the illumination is not superimposed in the x direction, the illuminance distribution in the x direction is greatly influenced by the light emission distribution of the lamp 1. 4A is an optical path diagram when the light source 2 is at the focal position of the reflector 4, and FIG. 4B is an optical path diagram when the light source 2 is shifted to the minus side in the x direction. In the state shown in FIG. 4A, the optical path is symmetrical on the positive side and the negative side in the x direction. On the other hand, in the state shown in FIG. 4B, the light source 2 is shifted to the minus side in the x direction and the light L emitted in the direction perpendicular to the optical axis is focused on the plus side. The minus side becomes asymmetrical like divergence. Therefore, the light quantity distribution as shown in FIGS. 12A and 12B is obtained, and the illuminance distribution on the image display element 40 is as shown in FIG.

FIG. 5 shows an optical path diagram from the light source 2 to the image display element 40. The solid line shown in FIG. 5A indicates the optical path when the light source 2 is at the focal position of the reflector 4 and the dotted line indicates the optical path when the light source 2 is shifted to the minus side in the x direction. Since the focal position of the light source 2 and the first light beam compression lens 16 is substantially conjugated with respect to the x direction, the optical path in the vicinity of the focal position of the first light beam compression lens 16 is matched to the positional deviation of the light source 2. I will be close . For this reason , the greatly offset light contributes to an increase in the amount of light on the negative side of the image display element 40. Therefore, as shown in FIG. 5B, if a light shielding plate 20 that shields the optical path in the x direction is installed, the light on the higher light quantity side on the image display element 40 can be blocked, and the right and left light quantities are uniform. Can be

In the present embodiment, the light-shielding portion 24 is disposed at a position away from the optical axis, and superimposing illumination is performed only in the y direction. That is, as shown in FIG. 6A, the light emission distribution of the lamp 1 is divided into a plurality of regions arranged in the vertical direction, and each is superimposed on the image display element 40, so that substantially uniform illumination can be performed. I have to. It is assumed that the light emitting area of the lamp 1 is about 40 mm × 40 mm, and the second integrator 14 is composed of nine lenses arranged in a vertical pitch of 4.5 mm . In that case, as shown in FIG. 6B, it is preferable that the light-shielding portion 24 is light-shielded with a width a of 4.5 mm around a position separated from the optical axis by a distance b of about 9 mm. This greatly contributes to the illumination in the vicinity of the position where the portion 6 shown in FIG. 6A becomes the maximum brightness value on the screen near the position 42 shown in FIG. 6C on the image display element 40. This is because a large change in illuminance is eliminated by blocking the light in that portion. Here, the portion 6 is in the vicinity of a position of ± about 9 mm in the Y direction from the optical axis. Further, the position 42 is a position that is shifted from the end to the center by the length of about 1/6 of the horizontal width of the projected image. In other words, the position 42 is about the horizontal width of the image from the center of the projected image. The position is shifted in the left-right direction by 1/3. A human eye that has a monotonically increasing light amount from the center of the screen to the edge does not feel a sense of incongruity to human eyes, but there is an inflection point (or maximum or minimum value) in the middle as shown in FIG. Such a thing becomes more uncomfortable as the inclination near the inflection point is larger, and is recognized as deterioration in image quality. For this reason, it is preferable to suppress a change in the amount of light in the vicinity of the position 42 shown in FIG.

  The height and width of the light shielding portion 24 are not limited to this. What is necessary is just to provide optimal light shielding by the number of upper and lower divisions of the second integrator 14, the pitch, the compression rate of the pupil of the first light beam compression lens 16 to the second light beam compression lens 32, and the like. For example, when the pitch of the second integrator 14 is fine, a means for reducing the width of the light shielding portion in accordance with the pitch can be considered. Further, the light shielding portions 24 do not correspond to the upper and lower ones of the second integrator 14, but correspond to the two light shielding portions 24A of the light shielding plate 20A shown in FIG. You may increase the area to be. Here, FIG. 7 is a schematic plan view of a light shielding plate 20 </ b> A as a modification of the light shielding plate 20. Similar to the light shielding plate 20, the light shielding plate 20A includes an opening 22A and a light shielding portion 24A.

  Here, as shown in FIG. 6B or FIG. 7, in this embodiment, it is possible to use a light shielding plate having a plurality of different types of opening regions (openings). The common points regarding the opening areas of the plurality of light shielding plates will be described below.

The direction of integration (Y direction in the figure) is a direction perpendicular to both the first direction, the first direction, and the optical axis (the optical axis of the illumination optical system and / or the optical axis of the reflector) (X in the figure). (Direction) is the second direction, and the coordinate system is defined by the first direction and the second direction. At this time, the width of the opening region in the second direction decreases and increases as it moves away from the optical axis position along the first direction (as it proceeds in the + Y direction or as it proceeds in the -Y direction in the figure). . More specifically, the width in the second direction at a position moved 9 mm in the ± Y direction from the optical axis position is smaller than the width in the second direction at the optical axis position, and increases as the distance further increases. And

Further, the opening area including the optical axis has a width in the second direction at the optical axis position of the opening area as W11 . Moreover, the second width of the optical axis along the first direction a predetermined distance L 1 position and W 12. Also, when the second width of the optical axis along the first direction separated by a predetermined distance 3/2 × L 1 position and W 13, W 11> W 12 <L1 satisfying the relationship of W 13 is It is desirable to have a configuration that exists. Further, the opening area including the optical axis has a width in the second direction at the optical axis position of the opening area as W21. Further, the width in the second direction at a position away from the optical axis by a predetermined distance L2 along the first direction is defined as W22. Further, when the width in the second direction at a position away from the optical axis by a predetermined distance of 2 × L2 along the first direction is W23, L2 that satisfies the relationship of W21> W22 <W23 exists. Is desirable. Here, L1 is 9 mm in FIG. 6B and FIG. Of course, values other than 9 mm may be used. In FIGS. 6B and 7, the above formula is established in both the + Y direction and the −Y direction, but the configuration can be established only in either the + Y direction or the −Y direction. It does not matter.

  Further, when the width of the opening region in the first direction at the optical axis position is W1, and the width in the second direction at the optical axis position is W2, it is desirable that W1> W2.

  Further, in this embodiment, as shown in FIG. 6B and FIG. 7, the opening region is surrounded by only a plurality of straight lines, but of course, it may be surrounded only by curves, and the straight lines and the curves are interwoven. You can surround it.

  Moreover, the illumination optical system 10 can be used as a part of a projection display device by combining the projection lens 50 as shown in FIG. Here, FIG. 8A is a simplified optical path diagram showing the YZ section of the projection display device, and FIG. 8B is a simplified optical path diagram showing the XZ section of the projection display device. It is. In FIG. 8, the number of image display elements is one. However, the present invention is not limited to this, and a plurality of image display elements are used as described later with reference to FIG. May be.

In the embodiment shown in FIG. 8, the projection display device includes a control unit 60, a detection unit 62, a drive unit 64, and an alarm 66, and the light shielding plate 20 is configured to be detachable from the optical path. The detection unit 62 detects the illuminance distribution on the image display element 40, but may detect the light emission state or the light amount distribution of the lamp 1. In the state shown in FIG. 11, since the lamp 1 is operating normally, it is not always necessary to insert the light shielding plate 20 . Therefore , in the present embodiment, only when the detection unit 62 detects the abnormality of the lamp 1, the control unit 60 is mounted on the light path of the light shielding plate 20 based on the detection result by the detection unit 62. Is configured to control driving.

The detection unit 62 can detect which mountain is abnormal or deteriorated in FIG. 12B or 12C. For this reason, in another embodiment, a plurality of types (at least two types) of light shielding plates 20 are prepared in a turret (not shown ) . Then , the control unit 60 can control the drive unit 64 so that any one of the plurality of types of light shielding plates 20 is mounted on the optical path based on the detection result by the detection unit 62. Examples of such a plurality of types of light shielding plates 20 are shown in FIG. 9A to FIG.

FIG. 9D shows a light shielding plate 20E having an opening 22E and a light shielding part 24E necessary for correcting a state where the left peak is abnormal or deteriorated, as shown in FIG. 12B. Yes. FIG. 9C shows an opening 22D and a light shielding part 24D necessary for correcting the abnormal or deteriorated state of the right peak (formed in the second direction opposite to the opening shape of the light shielding plate 20E). A light shielding plate 20D having an opening shape) is shown. As shown in FIGS. 9C and 9D, the light shielding portions 24 do not have to be arranged symmetrically in a direction perpendicular to the arrangement direction of the lens cells. Further, although the effect of correcting from the dotted line shown in FIG. 3 to the solid line is reduced, a shape having a light-shielding portion only in one of the vertical directions may be used. For example, the shape shown in FIGS. 9A and 9B. In this case, the effect of correcting from the dotted line to the solid line shown in FIG. 3 is halved, and the corrected line is between the dotted line and the solid line.

  If the deterioration or abnormality of the lamp 1 is large, the control unit 60 may notify the operator that the lamp 1 should be replaced via the alarm 66 without performing correction by the light shielding plate 20. In this case, a memory (not shown) is connected to the control unit 60, the memory stores conditions to be replaced, and the control unit 60 performs correction by the light shielding plate 20 from the detection result by the detection unit 62 and information in the memory. Whether to use the alarm 66 is determined.

  The detection unit 62 is not limited to detecting the illuminance distribution on the image display element 40, and may detect an entire white projection image (not shown) that has passed through the projection lens 50.

  According to the illumination optical system 10, it is possible to alleviate illuminance unevenness that occurs due to the eccentricity of the asymmetric light source 2.

Hereinafter, with reference to FIG. 10, a liquid crystal projector 100 as a projection type image display apparatus according to an embodiment of the present invention will be described. Here, FIG. 10 is a schematic block diagram of the liquid crystal projector 100. As shown in FIG. 10, the liquid crystal projector 100 includes a polarized light source unit 102, a dichroic mirror 104, a light generation unit 110, a light generation unit 130, a light synthesis prism (color synthesis prism) 150, and a projection optical system 160. Have

The polarized light source unit 102 includes the illumination optical system described in FIG. 1 and the like, but is omitted in FIG. Here, the polarized light source unit 102 has a function of guiding illumination light in a predetermined polarization state to the dichroic mirror 104. A light source that emits white light with a continuous spectrum along a light path from the light source side toward the projection optical system 160 and a lamp that includes a reflector that reflects the light in a predetermined direction are included. The first lens array includes a plurality of first lens elements ( first cylindrical lenses) arranged in a predetermined direction substantially orthogonal to the optical axis. In addition, a second lens element is arranged in which a plurality of second lens elements (second cylindrical lenses) that are arranged in a predetermined direction corresponding to the plurality of first lens elements and receive individual light beams divided and condensed by the first lens array are arranged. It has a lens array. Moreover, it has a polarization conversion element (a polarization conversion element array in which a plurality of polarization conversion elements are arranged in a predetermined direction) that aligns non-polarized light with predetermined polarized light. Moreover, it has a condenser lens, a bending mirror, and a field lens.

  The dichroic mirror 104 is a color separation mirror that reflects only a specific wavelength region of visible light and transmits the others, and in this embodiment, reflects light in the red (R) and blue (B) wavelength regions, Transmits light in the green (G) wavelength region.

The light generation unit 110 guides RB light in a predetermined polarization state to the light combining prism 150 . The light generation unit 110 includes color selective phase difference plates 112 a and 112 b, reflection type liquid crystal display elements 114 a and 114 b, quarter wavelength plates 116 a and 116 b, and a polarization beam splitter (PBS) 120.

  The color selective phase difference plates 112 and 112ba convert the polarization direction of the B light by 90 degrees and do not convert the polarization direction of the R light. The reflective liquid crystal display element 114a modulates the incident R light and reflects the R image. The reflective liquid crystal display element 114b modulates the incident B light and reflects the B image. The quarter-wave plates 116a and 116b change the linearly polarized light into elliptically polarized light (including circularly polarized light) and the elliptically polarized light into linearly polarized light. The quarter-wave plate 116a is provided for R light, and has a quarter wavelength. The plate 116b is provided for B light.

  The PBS 120 transmits P-polarized light and reflects S-polarized light. The PBS 120 includes an end face 121 through which RB illumination light passes, an end face 122 through which B light passes through the reflective liquid crystal display element 114b, an end face 123 through which R light passes through the reflective liquid crystal display element 114a, and projection of the RB. An end face 124 through which light is transmitted is provided. On each end face (light passage surface) 121 to 124, an antireflection film 125 having spectral reflection characteristics having minimum values of reflectance in the R wavelength region and the B wavelength region (wavelength region) is formed.

  The light generation unit 130 guides G light in a predetermined polarization state to the light combining prism 150, and includes a reflective liquid crystal display element 132, a quarter wavelength plate 134, and a PBS 140.

  The reflective liquid crystal display element 132 modulates incident light to reflect the G image. The quarter-wave plate 134 is provided for G light by changing linearly polarized light into elliptically polarized light (including circularly polarized light) and changing elliptically polarized light into linearly polarized light.

The PBS 140 transmits P-polarized light and reflects S-polarized light. The PBS 140 has an end surface 141 through which G illumination light is transmitted, an end surface 142 through which G light is transmitted to the reflective liquid crystal display element 132 , and an end surface 143 through which G projection light is transmitted. An antireflection film 145 having a spectral reflection characteristic having a minimum reflectance in the G wavelength region is formed on each end face (light passage surface) 141 to 143.

Since the light flux from the polarized light source unit 102 to the projection optical system 160 is the thinnest in the reflective liquid crystal display elements 114 a, 114 b and 132, the PBSs 120 and 140 arranged in the vicinity of the reflective liquid crystal display elements are more than the color synthesis prism 150. It is small.

The projection optical system (projection lens) 160 projects a color image on a screen (projected surface) ( not shown ) . The Fno of the projection optical system 160 is set to be brighter than the Fno of the illumination system in consideration of the deviation between the optical axis of the projection lens and the optical axis of the condensing optical system due to diffraction and attachment errors in the reflective liquid crystal display element.

  The illumination optical system 10 of this embodiment includes an optical path from the polarized light source 102 to the reflective liquid crystal display element 114a, an optical path from the polarized light source 102 to the reflective liquid crystal display element 114b, and a reflective liquid crystal display element from the polarized light source 102 to the reflective liquid crystal display element 114b. Each of the optical paths up to 132 can be applied. In this case, the image display element 40 is a reflective liquid crystal display element 114a, 114b, or 132.

  Hereinafter, the operation of the liquid crystal projector 100 will be described.

  Light from the polarized light source 202 that emits white light whose polarization state is aligned in a predetermined direction is reflected by the dichroic mirror 104, while the B and R light is reflected and the G light is transmitted.

  The R and B lights reflected by the dichroic mirror 104 are incident on the color selective phase difference plate 112a, whereby the B light is incident on the PBS 120 as P-polarized light and the R light is incident on S-polarized light. In PBS 120, the R light reflects off the polarization separation surface and reaches the reflective liquid crystal display element 114a, and the B light passes through the polarization separation surface and reaches the reflection type liquid crystal display element 114b. As a result, it is separated into two colored lights (RB).

  The PBS 120 is adjusted so that the purity of the P-polarized light contained in the reflected light and the purity of the S-polarized light contained in the transmitted light are substantially equal, thereby maintaining the balance between R and B and ensuring color reproducibility. Is done.

  The reflective liquid crystal display element 114a modulates the R light and reflects it. The S-polarized component of the reflected R light is reflected again by the polarization separation surface, returned to the light source side, and removed from the projection light. On the other hand, the P-polarized component of the R reflected light is transmitted through the polarization separation surface of the PBS 120 and analyzed, and becomes projection light.

  The reflective liquid crystal display element 114b modulates the B light and reflects it. The P-polarized component of the reflected B light is transmitted again through the polarization separation surface, returned to the light source side, and removed from the projection light. On the other hand, the S-polarized component of the reflected B light is reflected and analyzed by the polarization separation surface of the PBS 120, and becomes projection light.

  As a result, the B and R projection lights are combined into one light beam. The combined R and B projection light enters the color selective phase difference plate 112b. The color-selective phase difference plate 112b rotates only the polarization direction of R by 90 degrees, and both R and B are changed to S-polarized light. Then, the color-selective retardation plate 112b is incident on the color combining prism 150 and reflected by the polarization separation surface. Synthesized.

  In the G optical path, the G light transmitted through the dichroic mirror 104 enters the PBS 140 as S-polarized light, is reflected by the polarization separation surface of the PBS 140, and reaches the reflective liquid crystal display element 132. The reflective liquid crystal display element 132 modulates the G light and reflects it. The reflected S-polarized component of the G light is reflected again by the polarization separation surface, returned to the light source side, and removed from the projection light. On the other hand, the P-polarized component of the reflected light of G is transmitted through the polarization separation surface of the PBS 140, analyzed, and becomes projection light.

  The PBS 140 has a characteristic that the purity of the S-polarized light of the reflected light is particularly high, whereas the transmitted light has a characteristic that the purity of the polarized light is slightly inferior to that of the normal PBS. By using the PBS having such characteristics, at least the P component of the light reflected by the reflective liquid crystal display element 132 and emitted from the PBS 140 becomes a P component for displaying an image.

  The light transmitted through the PBS 140 enters the color synthesis prism 150 as P-polarized light, and unnecessary components are removed, and the light reaches the projection optical system 160. The RB light emitted from the PBS 120 and the G light emitted from the PBS 140 are combined by the color combining prism 150, reach the projection optical system 160, and are projected onto a screen or the like. The antireflection films 125 and 145 project a high-quality (high contrast) image on the screen.

  As mentioned above, although preferable embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary. For example, in this embodiment, the color combining prism 150 guides the reflected light of RB light and the transmitted light of G light to the projection optical system 160, but projects the transmitted light of RB light and the reflected light of G light. The light may be guided to the optical system 160. Further, a configuration in which B is a single optical path and RG is a common optical path, or a system using a cross prism may be used.

It is the simplified optical path figure of the illumination optical system of one Example of this invention. It is a schematic plan view of the light-shielding plate used for the illumination optical system shown in FIG. It is a graph for demonstrating the effect of the light-shielding plate shown in FIG. It is an optical path diagram for demonstrating the change of the light emission distribution in the state which the light source of the illumination optical system shown in FIG. 1 exists in the state which is in the focus position of a reflector, and shifted | deviated from the focus position. It is an optical path diagram for demonstrating the effect of the light-shielding plate in the illumination optical system shown in FIG. It is a figure for determining the shape of the light-shielding plate shown in FIG. It is a schematic plan view of the modification of the light-shielding plate shown in FIG. It is the simplified optical path figure of the projection type image display apparatus of one Example of this invention. It is a schematic plan view which shows various shapes of the light-shielding plate which can be used for the projection type image display apparatus shown in FIG. It is a schematic block diagram of the projection type image display apparatus of another Example of this invention. It is a figure which shows light quantity distribution when the lamp | ramp of the illumination optical system shown in FIG. 1 is normal. It is a figure which shows light quantity distribution when the lamp | ramp of the illumination optical system shown in FIG. 1 is abnormal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Illumination optical system 12 1st integrator 14 2nd integrator 16 1st light beam compression lens 20, 20A-20E Light-shielding plate 40 Image display element 50 Projection lens 100 Liquid crystal projector (projection type image display apparatus)
114a, 114b, 132 Reflective liquid crystal display element

Claims (13)

A first integrator that receives light from the light source unit and includes a plurality of first cylindrical lenses arranged in a first direction substantially orthogonal to the optical axis;
A second integrator having a plurality of second cylindrical lenses arranged in a direction parallel to the first direction so as to correspond to the first cylindrical lens and capturing individual light beams divided and condensed by the first integrator;
The light passing through the second integrator has a light collecting means to collect light, a illumination optical system for illuminating a target surface,
When the second direction is the first direction and the direction perpendicular to the optical axis,
The condensing means condenses light that has passed through the second integrator only in the second direction,
A light-shielding plate that shields light on the higher light amount side of the portion of the light beam collected by the condensing unit where the light emission distribution of the light source unit is asymmetric in the second direction is collected by the condensing unit. An illumination optical system characterized by being arranged in the vicinity of a position . A plane along the second direction is a first plane,
When the focal length in the first plane of the light collecting means is f,
The light shielding plate is disposed at a condensing position of the light that has passed through the second integrator on the first plane, or at a distance within 0.3f from the condensing position along the optical axis. the illumination optical system according to claim 1, wherein the. The light shielding plate has an opening region including the optical axis ,
The second width of the front Symbol opening area, according to claim 1 or 2, wherein the declined follow the distance along the optical axis or al the first direction, characterized in that it increases the further away Illumination optical system. The light shielding plate has an opening region including the optical axis ,
Before Symbol opening area, the width of the second direction of the optical axis position W11,
The width of the opening region in the second direction at a position away from the optical axis by a distance L1 along the first direction is W12,
When the width of the second region at a position 3/2 × L1 away from the optical axis along the first direction from the optical axis is W13,
W12 <W11
W12 <W13
The illumination optical system according to any one of claims 1 to 3, characterized in that L1 is present to satisfy the relationship. The light shielding plate has an opening region including the optical axis ,
Before Symbol opening area, the width of the second direction of the optical axis position W21,
The width of the opening region in the second direction at a position away from the optical axis along the first direction by a distance L2 is W22,
When the width in the second direction at a position 2 × L2 away from the optical axis along the first direction from the optical axis is W23,
W22 <W21
W22 <W23
The illumination optical system according to any one of claims 1 to 4, characterized in that L2 is present to satisfy the relationship. The light shielding plate has an opening region including the optical axis ,
The width of the opening region in the first direction at the optical axis position is W1,
When the width in the second direction at the optical axis position of the opening region is W2,
W1> W2
The illumination optical system according to any one of claims 1 to 5, characterized in that. The illumination optical system according to claim 1 , wherein the light source and the position where the light shielding plate is disposed have a substantially conjugate relationship. Claim wherein the light shielding plate portion shielded, characterized in that are arranged symmetrically with respect to the optical axis direction, and / or the second direction of the coordinate system is defined as the optical axis direction by the second direction the illumination optical system according to 1. The light shielding plate, the illumination optical system according to claim 1, characterized in that it has an opening shape that is determined by the pitch of the second cylindrical lens in the second direction. An illumination optical system according to any one of claims 1 to 9,
It said illuminated by the illuminating optical system, an image display device for modulation of the illumination light incident,
Projection type image display apparatus characterized by having a projection optical system for projecting light by the image display device is modulated on the projected surface. The projection type image display device further includes a detection unit that detects a light emission state of the light source unit or an illuminance distribution on the image display element,
The light shielding plate is configured to be detachable with respect to the optical path of the illumination light,
Projection type image display device according to claim 10, characterized in that it comprises a control unit for controlling the insertion and removal with respect to the optical path of the light shielding plate on the basis of the detection result by the detector. The light shielding plate has at least two types of opening shapes formed in opposite directions with respect to the first direction or the second direction in a coordinate system defined by an optical axis direction, the first direction, and the second direction. Including shading plate,
The projection type image display according to claim 11, wherein the control unit inserts / removes one of the two types of light shielding plates with respect to the optical path based on a detection result by the detection unit. apparatus. The control unit, on the basis of the detection unit of the result, the projection type image display apparatus according to claim 11 or 12, characterized in that a notification to the effect that replacing the light source unit.