WO2017130924A1 - Optical unit, and projector provided therewith - Google Patents

Optical unit, and projector provided therewith Download PDF

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Publication number
WO2017130924A1
WO2017130924A1 PCT/JP2017/002226 JP2017002226W WO2017130924A1 WO 2017130924 A1 WO2017130924 A1 WO 2017130924A1 JP 2017002226 W JP2017002226 W JP 2017002226W WO 2017130924 A1 WO2017130924 A1 WO 2017130924A1
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WO
WIPO (PCT)
Prior art keywords
light
prism
digital micromirror
optical unit
tir
Prior art date
Application number
PCT/JP2017/002226
Other languages
French (fr)
Japanese (ja)
Inventor
正嗣 冨岡
禎允 今村
寺田　昌弘
Original Assignee
コニカミノルタ株式会社
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Application filed by コニカミノルタ株式会社 filed Critical コニカミノルタ株式会社
Priority to JP2017564247A priority Critical patent/JPWO2017130924A1/en
Publication of WO2017130924A1 publication Critical patent/WO2017130924A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/04—Prisms
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/02—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the intensity of light
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details

Definitions

  • the present invention relates to an optical unit having a digital micromirror device and a projector including the same.
  • a conventional optical unit is disclosed in Patent Document 1.
  • the optical unit is mounted on a projector and includes a TIR prism, a dichroic prism, and a plurality of digital micromirror devices.
  • a TIR prism and a dichroic prism are arranged in this order from the projection side toward the digital micromirror device.
  • a digital micromirror device is a reflection type image display element having a rectangular shape in plan view, and has an image display surface composed of a plurality of minute micromirrors.
  • the digital micromirror device forms an image by controlling the intensity of illumination light by controlling the inclination of the surface of each micromirror.
  • Each micromirror rotates about a rotation axis orthogonal to the longitudinal direction of the digital micromirror device, and the tilt angle of the micromirror in the ON state is different from the tilt angle of the micromirror in the OFF state.
  • the TIR prism (Total Internal Reflection Prism) totally reflects the white illumination light incident from the incident surface to the dichroic prism.
  • the dichroic prism has two dichroic coat surfaces that intersect, and separates the white illumination light emitted from the TIR prism into red, green, and blue illumination light and guides them to each digital micromirror device.
  • the dichroic prism color-synthesizes red, green, and blue ON lights reflected by the ON micromirrors of each digital micromirror device, and emits them toward the TIR prism.
  • Each digital micromirror device is a dichroic prism so that the intersection of the two dichroic coat surfaces coincides with the longitudinal direction of the digital micromirror device when viewed from the normal direction of the digital micromirror device. It is arrange
  • the white illumination light incident on the TIR prism is decomposed by the dichroic prism, and the red, green, and blue illumination lights enter different digital micromirror devices.
  • the red, green, and blue ON lights reflected by the ON micromirrors of each digital micromirror device are color-combined by the dichroic prism and emitted to the projection side via the TIR prism. Thereby, a color image is projected.
  • the illumination light is transmitted through the TIR prism and the dichroic prism in this order, and is guided to each digital micromirror device.
  • the projection is performed on a plane perpendicular to the intersecting line of the two dichroic coat surfaces, and the optical axis of the ON light and the optical axis of the illumination light are shifted in the dichroic prism.
  • the optical unit is increased in size, it is necessary to ensure a long back focus of the projection lens of the projector, so that the degree of freedom in designing the projection lens is reduced. This makes it difficult to design a high-performance projection lens.
  • the present invention is a plan view in which an image is formed by intensity-modulating illumination light by controlling ON / OFF of the inclination of each surface of a plurality of micromirrors that rotate about a rotation axis.
  • a plurality of substantially rectangular digital micromirror devices A plurality of TIR prisms provided corresponding to each of the digital micromirror devices and guiding illumination light having different wavelengths to each of the digital micromirror devices;
  • a color synthesizing prism that color-synthesizes the ON light reflected by each of the micromirrors in the ON state of each of the digital micromirror devices and emits the light to the projection side;
  • An optical unit comprising: Placing the TIR prism between the digital micromirror device and the color combining prism;
  • the color synthesis prism has a first dichroic coating surface and a second dichroic coating surface that reflect ON light having a predetermined wavelength and transmit ON light having a wavelength other than the predetermined wavelength.
  • an angle formed by an intersection line between the first dichroic coated surface and the second dichroic coated surface and a longitudinal direction of the digital micromirror device is 45 °. It is characterized by being smaller than.
  • the intersecting line substantially coincides with the longitudinal direction when viewed from the normal direction.
  • the rotation shaft is inclined by 45 ° with respect to the longitudinal direction.
  • the rotation axis is not orthogonal to the optical axis direction of incident light of the micromirror.
  • the normal line of the illumination light reflecting surface of the TIR prism is inclined with respect to the longitudinal direction when viewed from the normal direction.
  • the normal line on the optical axis of the ON light of the illumination light reflecting surface of the TIR prism and the normal line on the optical axis of the ON light of the micromirror in the ON state are the same. It is preferable to be on a plane.
  • the illumination light emitted from the TIR prism is guided to the micromirror, and the ON light reflected by the micromirror is transmitted in the order of the TIR prism and the color combining prism. preferable.
  • a projection-side prism in which the optical axis of the ON light is arranged in the normal direction of the emission surface is provided on the emission side of the color synthesis prism.
  • the projector of the present invention includes an optical unit configured as described above, a light source, an illumination optical system that emits illumination light having different wavelengths toward the TIR prisms of the optical unit, and the digital micromirror device. And a projection optical system for enlarging and projecting the displayed image on a screen.
  • the illumination light is incident from below the incident surface of the TIR prism.
  • the angle formed by the line of intersection between the first dichroic coat surface and the second dichroic coat and the longitudinal direction of the digital micromirror device Is smaller than 45 °.
  • a color composition prism can be made small.
  • a TIR prism is disposed between the digital micromirror device and the color synthesis prism.
  • the illumination light can be guided to each digital micromirror device without passing through the color synthesis prism. For this reason, even if the color synthesizing prism is made small, it is possible to secure a desired F number at the peripheral portion of the digital micromirror device.
  • the optical unit and the projector can be reduced in size.
  • the back focus of the projection optical system of the projector can be shortened, the degree of freedom in designing the projection optical system can be increased. Thereby, a high-performance projector can be provided.
  • FIG. 1 is a schematic configuration diagram showing a projector including an optical unit according to a first embodiment of the invention.
  • the perspective view which shows the optical unit of 1st Embodiment of this invention.
  • the top view which shows the optical unit of 1st Embodiment of this invention.
  • Side surface sectional drawing which shows the optical unit of 1st Embodiment of this invention.
  • the front view which shows the digital micromirror device of the optical unit of 1st Embodiment of this invention
  • Side surface sectional drawing which shows the optical unit of 3rd Embodiment of this invention.
  • FIG. 1 is a schematic configuration diagram of a projector including the optical unit according to the first embodiment.
  • the 3-chip type (three-plate type) projector PJ includes light sources 1R, 1G, and 1B, illumination optical systems 2R, 2G, and 2B, an optical unit PU, a projection optical system LN, an actuator 4, and a control unit 3.
  • the light sources 1R, 1G, and 1B and the illumination optical systems 2R, 2G, and 2B may be collectively referred to as “light source 1” and “illumination optical system 2”, respectively.
  • the light sources 1R, 1G, and 1B have red LEDs, green LEDs, and blue LEDs, respectively, and emit red light, green light, and blue light, respectively.
  • the illumination optical systems 2R, 2G, and 2B are provided corresponding to the light sources 1R, 1G, and 1B, respectively, and include an integrator, a relay lens group, a reflection mirror, and the like (all not shown).
  • the illumination optical system 2 condenses the light emitted from the light source 1 and emits the light toward the optical unit PU as illumination light L1.
  • the optical unit PU has a plurality of digital micromirror devices DP1 to DP3 having a substantially rectangular shape in plan view, a plurality of TIR prisms P11 to P13, one color synthesis prism P2, and one projection side prism P3, and a support member. (Not shown) is supported in the projector PJ.
  • the optical unit PU emits projection light (ON light described later) reflected by the digital micromirror devices DP1 to DP3 (see FIG. 3) toward the projection optical system LN.
  • the digital micromirror devices DP1 to DP3 and the TIR prisms P11 to P13 may be collectively referred to as “digital micromirror device DP” and “TIR prism P1”, respectively. Details of the optical unit PU will be described later.
  • the projection optical system LN has lenses 51 and 52 (see FIG. 3), and enlarges and projects an image displayed on the digital micromirror device DP onto the screen SC.
  • the actuator 4 moves the lenses 51 and 52 to perform, for example, zooming or focusing.
  • the control unit 3 has a CPU and controls the entire projector PJ.
  • FIG. 2 to 4 are a perspective view, a top view, and a side sectional view of the optical unit PU, respectively.
  • FIG. 4 shows a side sectional view through the digital micromirror device DP2. 2 to 4, the X direction indicates the thickness direction of the color combining prism P2. The Z direction indicates the optical axis direction of the projection light (ON light described later) reflected by the digital micromirror device DP2. The Y direction indicates a direction perpendicular to the X direction and the Z direction.
  • TIR prisms P11 to P13 are respectively arranged. Thereby, the TIR prisms P11 to P13 are provided corresponding to the digital micromirror devices DP1 to DP3, respectively.
  • a projection-side prism P3 is disposed on the projection side of the color synthesis prism P2.
  • a cover glass CG is provided between the digital micromirror device DP and the TIR prism P1.
  • illustration of the cover glass CG is abbreviate
  • FIG. 5 shows a front view of the digital micromirror device DP2. Since the configuration of the digital micromirror devices DP1 and DP3 is the same as that of the digital micromirror device DP2, the digital micromirror device DP2 will be described below as a representative.
  • FIG. 5 shows a state in which the digital micromirror device DP2 is viewed from the TIR prism P12 side, and the micromirror MR of the digital micromirror device DP2 is enlarged.
  • the digital micromirror device DP2 has a plurality of micromirrors MR having a square shape in plan view arranged in a matrix.
  • the micromirror MR is mounted on a substantially rectangular substrate SB, and the substrate SB is accommodated in a substantially rectangular housing (not shown).
  • the micromirror MR rotates about a rotation axis RA inclined by 45 ° with respect to the longitudinal direction (Y direction) of the substrate SB.
  • an intersection S between a first dichroic coat surface DR and a second dichroic coat DB of a color synthesizing prism P2 described later is the longitudinal direction of the digital micromirror device DP2. It almost coincides with (Y direction).
  • the angle ⁇ formed by the intersection line S and the longitudinal direction of the digital micromirror device DP2 is smaller than 45 °.
  • the digital micromirror device DP2 may be arranged to face the TIR prism P12.
  • FIG. 7 shows a perspective view of the micromirror MR in the ON state and OFF state of the digital micromirror device DP2.
  • a pixel reflecting surface (micromirror surface) MS constituting a pixel is formed by the micromirror MR.
  • the ON state of the micromirror MR is indicated by the reflecting surface MS2, and the OFF state of the micromirror MR is indicated by the reflecting surface MS3.
  • the micromirror MR is turned on by rotating ⁇ 12 ° around the rotation axis RA from the reference state (the normal direction of the micromirror MR coincides with the Z direction), and is turned + 12 °. It becomes OFF state.
  • each pixel reflection surface MS is ON / OFF controlled, and the micromirror MR is in an image display state (ON state).
  • Two angle states are taken: an image non-display state (OFF state). That is, the digital micromirror device DP2 drives the micromirror MR with respect to the rotation axis RA, and the micromirror MR can take a reference state, an ON state, and an OFF state.
  • the digital micromirror device DP2 constitutes a reflective image display element that generates a desired image by intensity-modulating the illumination light L1.
  • the micromirror MR in the ON state and the OFF state is inclined with respect to the XY plane.
  • the illumination light L1 incident on the micromirror MR is reflected in the normal direction of the image display surface DS and is turned on with the ON light L2 (projection light).
  • the ON light L2 projection light
  • the illumination light L1 incident on the micromirror MR is reflected with a large angle from the normal direction of the image display surface DS, and becomes OFF light L3 (unnecessary light).
  • the optical axis AX1 of the illumination light L1, the optical axis AX2 of the ON light L2, and the optical axis AX3 (see FIG. 4) of the OFF light L3 are arranged on the same plane.
  • a two-dimensional image is formed by intensity modulation of the illumination light L1.
  • the digital micromirror device DP2 expresses ON / OFF by driving the micromirror MR about one axis as described above.
  • the TIR prism P1 is composed of two prisms and has an incident surface 11, an illumination light reflecting surface 12, and exit surfaces 13, 14, and 15.
  • the incident surface 11 is inclined by about 45 ° with respect to the short direction of the digital micromirror device DP, and enters the illumination light L 1 emitted from the illumination optical system 2.
  • red, green, and blue illumination light L1 is incident on the incident surfaces 11 of the TIR prisms P11 to P13, respectively. That is, illumination lights L1 having different wavelengths are incident on the incident surfaces 11 of the TIR prisms P11 to P13.
  • FIG. 8 shows a perspective view of the TIR prism P12. Since the TIR prisms P11 and P13 have the same configuration as the TIR prism P12, the TIR prism P12 will be described below as a representative.
  • the illumination light reflecting surface 12 is inclined so as to approach the digital micromirror device DP2 as the distance from the illumination optical system 2 (see FIG. 1) increases, and the illumination light L1 incident from the incident surface 11 enters the digital micromirror device DP2. Total reflection toward.
  • the normal N12 of the illumination light reflecting surface 12 is inclined with respect to the longitudinal direction (Y direction) of the digital micromirror device DP2. Thereby, the TIR prism P12 can efficiently guide the illumination light L1 to the digital micromirror device DP2.
  • the normal line on the optical axis AX2 of the ON light L2 of the illumination light reflecting surface 12 of the TIR prism P1 and the normal line on the optical axis AX2 of the ON light L2 of the micromirror MR in the ON state corresponding to the TIR prism P1 Are on the same plane.
  • the exit surface 13 faces the cover glass CG (see FIGS. 3 and 4) of the digital micromirror device DP, and the illumination light L1 totally reflected by the illumination light reflecting surface 12 is directed toward the digital micromirror device DP2.
  • the emission surface 14 faces the color synthesis prism P2, and emits the ON light L2 reflected by the digital micromirror device DP2.
  • the exit surface 15 is formed by an end surface (end surface in the Y direction) opposite to the entrance surface 11 with respect to the optical axis AX2 of the ON light L2, and emits the OFF light L3.
  • the color synthesizing prism P2 includes a so-called Philips type dichroic prism, and includes three prisms P21 to P23.
  • the prisms P22, P23, and P21 are arranged in this order from the TIR prism P12 toward the projection optical system LN.
  • Each of the prisms P21 to P23 has an entrance surface 21, and each entrance surface 21 faces the exit surface 14 of each of the TIR prisms P11 to P13.
  • the prisms P21 and P23 each have a total reflection surface 22, and each have a first dichroic coating surface DR and a second dichroic coating surface DB.
  • an emission surface 23 for emitting the color-combined ON light L2 is formed on the projection side of the prism P21.
  • the first dichroic coat surface DR and the total reflection surface 22 of the prism P23 are inclined so as to be separated from the digital micromirror device DP2 as the distance from the TIR prism P11 is increased.
  • the second dichroic coating surface DB and the total reflection surface 22 of the prism P21 are inclined so as to approach the digital micromirror device DP2 as the distance from the TIR prism P11 increases.
  • An intersection line S (see FIGS. 2 and 5) between the first dichroic coat surface DR and the second dichroic coat surface DB extends in the Y direction.
  • the first dichroic coat surface DR reflects the red ON light L2 and transmits the green and blue ON light L2.
  • the second dichroic coat surface DB reflects the blue ON light L2 and transmits the green ON light L2. That is, the first dichroic coated surface DR and the second dichroic coated surface DB reflect the ON light L2 having a predetermined wavelength and transmit the ON light L2 having a wavelength other than the predetermined wavelength.
  • the color combining prism P2 color-synthesizes the red, green and blue ON lights L2 emitted from the TIR prisms P11 to P13, respectively, and emits them to the projection side.
  • the prism P21 and the prism P23 may be interchanged. That is, the prism P23 may be disposed on the projection side with respect to the prism P21. Further, instead of the so-called Philips type dichroic prism, the color synthesis prism P2 may be formed by a cross dichroic prism.
  • the projection-side prism P3 is disposed on the exit side of the color synthesis prism P2, and has an entrance surface 31 and an exit surface 32.
  • the incident surface 31 is inclined so as to be closer to the digital micromirror device DP2 as it is farther from the TIR prism P11, and is transmitted through the color synthesis prism P2 and emitted from the emission surface 23 (projected light after color synthesis). Is incident.
  • the exit surface 32 is arranged to face the projection optical system LN, and emits the ON light L2 so that the optical axis AX2 of the ON light L2 coincides with the normal direction of the exit surface 32.
  • the distortion of the image projected on the screen SC by the projection side prism P3 can be reduced. Further, the end portions of the TIR prisms P11 and P13 on the projection optical system LN side protrude toward the emission side with respect to the emission surface 32 of the projection side prism P3.
  • glass can be used as the material of the TIR prism P1, the color synthesis prism P2, and the projection side prism P3.
  • the TIR prism P1, the color synthesis prism P2, and the projection side prism P3 are made of glass having the same refractive index.
  • the support members are arranged in contact with the upper and lower surfaces of the optical unit PU (both end surfaces in the Y direction of the color combining prism P2), and sandwich the optical unit PU.
  • an air gap (not shown) is provided between the TIR prism P1 and the color combining prism P2, and between the color combining prism P2 and the projection side prism P3.
  • An air gap (not shown) is also provided between the plurality of prisms in the TIR prism P1 and between the prisms P21 to P23 in the color synthesis prism P2.
  • a light absorbing member PT is provided facing away from the end face (upper surface) in the Y direction of the color combining prism P2.
  • the light absorbing member PT is formed of, for example, a black-treated metal plate, and absorbs the OFF light L3 emitted from the emission surface 15 of the TIR prism P1. Thereby, it is possible to prevent thermal deformation of other members in the projector PJ due to the OFF light L3 emitted from the optical unit PU.
  • the projector PJ having the above configuration, when red light, green light, and blue light are emitted from the light sources 1R, 1G, and 1B (see FIG. 1), respectively, they are condensed by the illumination optical systems 2R, 2G, and 2B, respectively, and red.
  • the green and blue illumination light L1 is emitted toward the optical unit PU.
  • the red, green, and blue illumination light L1 is incident on the incident surface 11 of each of the TIR prisms P11 to P13 and then totally reflected by the illumination light reflecting surface 12.
  • the red, green, and blue illumination lights L1 totally reflected by the illumination light reflecting surface 12 are emitted from the emission surface 13, and then pass through the cover glass CG and enter the digital micromirror devices DP1 to DP3, respectively.
  • the TIR prisms P11 to P13 guide the illumination lights L1 having different wavelengths to the digital micromirror devices DP1 to DP3, respectively, without passing through the color synthesis prism P2.
  • the rotation axis RA is not orthogonal to the optical axis direction of the incident light of the micromirror MR, the illumination light L1 can be efficiently guided to the digital micromirror device P1.
  • the red, green, and blue ON lights L2 reflected by the micromirrors MR in the ON state of the digital micromirror devices DP1 to DP3 are transmitted through the illumination light reflecting surface 12 and then each color combining prism P2 via the incident surface 21. Is incident on.
  • the red ON light L ⁇ b> 2 is totally reflected by the total reflection surface 22 of the prism P ⁇ b> 21, then reflected by the first dichroic coat surface DR, and directed toward the emission surface 23.
  • the green ON light L ⁇ b> 2 passes through the prism P ⁇ b> 22 and then passes through the second dichroic coat surface DB and the first dichroic coat surface DR in this order and travels toward the exit surface 23.
  • the blue ON light L2 is totally reflected by the total reflection surface 22 of the prism P23, then reflected by the second dichroic coat surface DB, passes through the first dichroic coat surface DR, and travels toward the emission surface 23. At this time, the ON light L2 of each color is color-synthesized while passing through the color synthesis prism P2, and the color-synthesized ON light L2 is emitted from the emission surface 23 to the projection side.
  • the ON light L2 emitted from the emission surface 23 of the color synthesis prism P2 enters the projection-side prism P3 via the emission surface 31.
  • the ON light L2 incident on the projection side prism P3 passes through the projection side prism P3 and is emitted from the emission surface 32 toward the projection optical system LN.
  • the ON light L2 incident on the projection optical system LN is projected on the screen SC (see FIG. 1).
  • the color image displayed on the digital micromirror device DP is enlarged and projected on the screen SC.
  • zooming and focusing are performed by the actuator 4.
  • the projection-side prism P3 emits the ON light L2 from the emission surface 32 so that the optical axis AX2 coincides with the normal direction of the emission surface 32. Thereby, distortion of the image enlarged and projected on the screen SC can be reduced.
  • the OFF light L3 reflected by the micromirror MR in the OFF state of the digital micromirror devices DP1 to DP3 is emitted from the emission surface 15 and is emitted to the outside of the optical unit PU.
  • the OFF light L3 emitted from the optical unit PU is absorbed by the light absorbing member PT (see FIG. 4). Thereby, it is possible to prevent the OFF light L3 from entering the projection optical system LN. Accordingly, it is possible to prevent the contrast of the projected image from being lowered.
  • the light absorbing member PT is provided apart from the emission surface 15. Thereby, the heat transfer to the optical unit PU of the heat
  • the illumination light L1 (flat light) reflected by the micromirror MR that is transitioning from one of the ON state and the OFF state to the other is in a direction opposite to the incident light of the illumination light L1 with respect to the normal direction of the micromirror MR. Reflected.
  • the reflected light of the illumination light L1 from the flat light or the cover glass CG is also incident on the TIR prism P1, and is then emitted from the emission surface 15. Thereby, it is possible to prevent the reflected light of the illumination light L1 from the flat light or the cover glass CG from entering the projection optical system LN. Therefore, it is possible to further prevent the contrast of the projected image from decreasing.
  • the intersection lines S of the first dichroic coated surface DR and the second dichroic coated surface DB are respectively represented by the digital micromirror devices DP1 to DP3. It substantially coincides with the longitudinal direction (Y direction) of DP3. Thereby, the image height of the ON light L2 can be reduced, and the length of the color combining prism P2 in the Z direction can be shortened.
  • the TIR prism P1 is disposed between the digital micromirror device DP and the color synthesis prism P2.
  • the illumination light L1 passes through the TIR prism P1 without passing through the color synthesis prism P2, and is guided to the digital micromirror device DP. For this reason, even if the width of the color synthesizing prism P2 in the Z direction is reduced, it is possible to secure a desired F number at the peripheral edge of the digital micromirror device DP. Therefore, the optical unit PU can be downsized, the back focus BF (distance from the rear end of the lens 52 to the image display surface DS) of the projection optical system LN can be shortened, and the projector PJ can be downsized.
  • the lengths in the Z direction of the color synthesis prism P2 of the optical unit PU of the present embodiment and the color synthesis prism of the optical unit of the comparative example were compared.
  • the angle ⁇ (see FIG. 6) formed between the longitudinal direction of the digital micromirror device DP and the intersection line S as viewed from the normal direction of the digital micromirror device DP is set to 45 °.
  • the TIR prisms P11 to P13 of this embodiment are omitted, and one TIR prism is arranged on the output side of the color synthesis prism.
  • Other configurations of the comparative example were the same as those of the optical unit PU.
  • the digital micromirror device DP having a length in the short-side direction and a lengthwise direction of about 16.3 mm and about 31.0 mm is used, and the periphery of the digital micromirror device DP is used.
  • the F number of the part was made the same.
  • the length of the comparative color synthesizing prism in the Z direction is about 82.5 mm, whereas the length of the optical unit PU of the present embodiment in the Z direction is about 76.1 mm.
  • the length of the PU color synthesis prism P2 in the Z direction is about 6.4 mm shorter than that of the comparative example. Therefore, the back focus BF of the projector PJ including the optical unit PU of the present embodiment can be made shorter than that in the comparative example. Since the illumination light L1 does not pass through the color synthesis prism P2, the optical path of the illumination light L1 can be shortened, and the TIR prism P1 can be made smaller than the TIR prism of the comparative example.
  • the intersection lines S between the first dichroic coated surface DR and the second dichroic coated surface DB are respectively digital micromirrors. -It substantially coincides with the longitudinal direction (Y direction) of the devices DP1 to DP3. Thereby, the image height of the ON light L2 can be reduced, and the length of the color combining prism P2 in the Z direction can be shortened.
  • the TIR prism P1 is disposed between the digital micromirror device DP and the color synthesis prism P2.
  • the illumination light L1 passes through the TIR prism P1 without passing through the color synthesis prism P2, and is guided to the digital micromirror device DP. For this reason, even if the width of the color synthesizing prism P2 in the Z direction is reduced, it is possible to secure a desired F number at the peripheral edge of the digital micromirror device DP. Therefore, the optical unit PU can be downsized, the back focus BF (distance from the rear end of the lens 52 to the image display surface DS) of the projection optical system LN can be shortened, and the projector PJ can be downsized.
  • the back focus BF of the projection optical system LN of the projector PJ can be shortened, the design freedom of the projection lenses 51 and 52 can be increased. Thereby, a high-performance projector PJ can be provided.
  • the angle ⁇ (see FIG. 6) formed by the intersecting line S and the longitudinal direction of the digital micromirror device DP is smaller than 45 ° when viewed from the normal ND direction, the image height of the ON light L2 is reduced. can do. For this reason, the back focus BF can be shortened by shortening the length of the color synthesis prism P2 in the Z direction. It is more desirable that the intersection line S substantially coincides with the longitudinal direction of the digital micromirror device DP because the back focus BF can be further shortened.
  • the rotation axis RA of the micromirror MR is inclined 45 ° with respect to the longitudinal direction of the digital micromirror device DP.
  • a general-purpose digital micromirror device DP can be used, and the manufacturing costs of the optical unit PU and the projector PJ can be reduced.
  • the rotation axis RA is not orthogonal to the optical axis direction of the incident light of the micromirror MR, the ON light L2 reflected by the digital micromirror device DP can be efficiently emitted toward the projection side. .
  • the normal N12 of the illumination light reflecting surface 12 of the TIR prism P1 is inclined with respect to the longitudinal direction of the digital micromirror device DP. Thereby, the illumination light L1 can be efficiently guided to the digital micromirror device DP.
  • the normal line on the optical axis AX2 of the ON light L2 of the illumination light reflecting surface 12 of the TIR prism P1 and the normal line on the optical axis AX2 of the ON light L2 of the micromirror MR in the ON state corresponding to the TIR prism P1 Are on the same plane. Thereby, the image height of the ON light L2 reflected by the digital micromirror device DP can be further reduced.
  • a projection-side prism P3 in which the optical axis AX2 of the ON light L2 is arranged in the normal direction of the emission surface 32 is provided on the emission side of the color synthesis prism P2.
  • the projector PJ also displays the illumination optical systems 2R, 2B, and 2G that emit red, green, and blue illumination light L1 toward the TIR prisms P11 to P13 of the optical unit PU, and the digital micromirror device DP.
  • the illumination light L1 enters from below the incident surface 11 of the TIR prism P1. Thereby, the light source 1 and the illumination optical system 2 can be gathered under the optical unit PU, and the design freedom of the projection optical system LN can be increased.
  • FIG. 9 shows a schematic configuration diagram of a projector PJ including the optical unit PU of the second embodiment.
  • 10 to 12 are a perspective view, a top view, and a side cross-sectional view, respectively, of the optical unit PU of the second embodiment.
  • the same reference numerals are assigned to the same parts as those in the first embodiment shown in FIGS.
  • the configuration of the TIR prism P1 is different from that of the first embodiment.
  • Other parts are the same as those in the first embodiment.
  • the incident surface 11 of the TIR prism P11 is inclined so as to approach the digital micromirror device DP1 as it approaches the TIR prism P12.
  • the incident surface 11 of the TIR prism P12 is inclined so as to approach the digital micromirror device DP2 as it approaches the TIR prism P13.
  • the incident surface 11 of the TIR prism P13 is tilted away from the digital micromirror device DP3 as it approaches the TIR prism P12.
  • the light absorbing member PT is disposed apart above the emission surface 15 of the TIR prisms P11 to P13.
  • the normal line on the optical axis AX2 of the ON light L2 of the illumination light reflecting surface 12 of the TIR prism P1 and the normal line on the optical axis AX2 of the ON light L2 of the micromirror MR in the ON state corresponding to the TIR prism P1 Are not coplanar.
  • the angle between the optical axis AX1 of the incident light of the micromirror MR and the XY plane is -17.5 ° and the angle between the YZ plane is 16.7 °.
  • the illumination light L1 is made incident from the incident surface 11.
  • the optical axis AX1 of the illumination light L1 and the incident surface 11 are perpendicular to each other.
  • the same effect as in the first embodiment can be obtained.
  • the normal line on the optical axis AX2 of the illumination light reflecting surface 12 and the normal line on the optical axis AX2 of the micromirror MR in the ON state are not on the same plane.
  • FIGS. 13 and 14 show a top view and a side sectional view of the optical unit PU of the third embodiment.
  • FIG. 15 shows a front view of the digital micromirror device DP2 of the optical unit PU of the third embodiment.
  • the same reference numerals are assigned to the same parts as those in the first embodiment shown in FIGS.
  • This embodiment is different from the first embodiment in that the rotation axis RA of the micromirror MR is parallel to the short direction of the digital micromirror device DP (perpendicular to the longitudinal direction).
  • the configuration of the TIR prism P1 is also different from that of the first embodiment. Other parts are the same as those in the first embodiment.
  • the incident surfaces 11 of the TIR prisms P11 to P13 are inclined so as to approach the digital micromirror devices DP1 to DP3, respectively, as they go from the color synthesis prism P2 to the digital micromirror devices DP1 to DP3, respectively. Further, the incident surfaces 11 of the TIR prisms P11 to P13 are not inclined with respect to the short direction of the digital micromirror devices DP1 to DP3, respectively.
  • the normal line on the optical axis AX2 of the ON light L2 of the illumination light reflecting surface 12 of the TIR prism P1 and the normal line on the optical axis AX2 of the ON light L2 of the micromirror MR in the ON state corresponding to the TIR prism P1 are the same. It is on a plane.
  • the illumination light L1 incident on the TIR prism P1 via the incident surface 11 is totally reflected by the illumination light reflecting surface 12, and then travels to the digital micromirror device DP corresponding to the TIR prism P1.
  • the optical axis AX1 of the illumination light L1 totally reflected by the illumination light reflecting surface 12 is substantially orthogonal to the rotation axis RA.
  • the ON light L2 reflected by the micromirror MR in the ON state is emitted from the TIR prism P1 so that the optical axis AX2 coincides with the normal direction of the digital micromirror device DP.
  • the same effect as in the first embodiment can be obtained.
  • the inclination of the incident surface 11 with respect to the short direction of the digital micromirror device DP can be made smaller than in the first and second embodiments, the light source 1 and the illumination optical system 2 are gathered below the optical unit PU. can do. Therefore, the degree of freedom in designing the projection optical system LN can be further increased.
  • FIGS. 16 and 17 show a perspective view and a top view of the optical unit PU of the fourth embodiment.
  • the cover glass CG is not shown.
  • the same reference numerals are assigned to the same parts as those in the first embodiment shown in FIGS.
  • This embodiment is different from the first embodiment in that the projection side prism P3 is omitted.
  • Other parts are the same as those in the first embodiment.
  • the TIR prism P1 is composed of the same TIR prism as in the first embodiment.
  • the prisms P22, P21, and P23 are arranged in this order from the TIR prism P12 toward the projection optical system LN.
  • the optical axis AX2 of the ON light L2 is arranged in the normal direction of the emission surface 23 of the color synthesis prism P2. That is, the emission surface 23 is formed perpendicular to the optical axis AX2.
  • the projection-side prism P3 is not disposed between the exit surface 23 and the projection optical system LN.
  • the projector PJ having the above-described configuration, when red light, green light, and blue light are emitted from the light sources 1R, 1G, and 1B (see FIG. 1), respectively, the light is condensed by the illumination optical systems 2R, 2G, and 2B, respectively.
  • the green and blue illumination light L1 is emitted toward the optical unit PU.
  • the red, green, and blue illumination light L1 is incident on the incident surface 11 of each of the TIR prisms P11 to P13 and then totally reflected by the illumination light reflecting surface 12.
  • the red, green, and blue illumination lights L1 totally reflected by the illumination light reflecting surface 12 are emitted from the emission surface 13, and then pass through the cover glass CG and enter the digital micromirror devices DP1 to DP3, respectively.
  • the red, green, and blue ON lights L2 reflected by the micromirrors MR in the ON state of the digital micromirror devices DP1 to DP3 are transmitted through the illumination light reflecting surface 12 and then each color combining prism P2 via the incident surface 21. Is incident on.
  • the red ON light L2 is totally reflected by the total reflection surface 22 of the prism P21, then reflected by the first dichroic coating surface DR, passes through the second dichroic coating surface DB, and travels toward the emission surface 23.
  • the green ON light L ⁇ b> 2 passes through the prism P ⁇ b> 22 and then passes through the first dichroic coat surface DR and the second dichroic coat surface DB in this order and travels toward the exit surface 23.
  • the blue ON light L ⁇ b> 2 is totally reflected by the total reflection surface 22 of the prism P ⁇ b> 23, then reflected by the second dichroic coating surface DB, and travels toward the emission surface 23.
  • the ON light L2 of each color is color-synthesized while passing through the color synthesis prism P2, and the color-synthesized ON light L2 is emitted from the emission surface 23 toward the projection optical system LN.
  • the ON light L2 incident on the projection optical system LN is projected on the screen SC (see FIG. 1).
  • the color image displayed on the digital micromirror device DP is enlarged and projected on the screen SC.
  • zooming and focusing are performed by the actuator 4.
  • the exit surface 23 of the color combining prism P2 emits the ON light L2 so that the optical axis AX2 of the ON light L2 coincides with the normal direction of the exit surface 23. Thereby, it is possible to reduce distortion of the image enlarged and projected on the screen SC while omitting the projection side prism P3.
  • the optical axis AX2 of the ON light L2 is arranged in the normal direction of the emission surface 23 of the color synthesis prism P2. Thereby, since the projection side prism P3 can be omitted, the number of parts of the optical unit PU can be reduced.
  • the prism P21 and the prism P23 may be interchanged. That is, the prism P21 may be arranged on the projection side with respect to the prism P23. In this case, the optical axis AX2 of the ON light L2 is arranged in the normal direction of the emission surface on the projection side of the prism P21 (the emission surface 23 of the color synthesis prism P2).
  • the same TIR prism P1 as that of the first embodiment is used.
  • the same TIR prism P1 as that of the second embodiment may be used instead.
  • the light sources 1R, 1G, and 1B may include a red laser diode, a green laser diode, and a blue laser diode, respectively, instead of the LED.
  • a light source that emits white light is provided instead of the light sources 1R, 1G, and 1B, and the white light is converted into red light, green light, and blue light using a dichroic filter or the like. After the color separation, the light may be incident on the incident surface 11 of each of the TIR prisms P11 to P13.
  • the present invention can be used for an optical unit having a digital micromirror device and a projector including the optical unit.
  • PJ Projector LN Projection optical system PU Optical unit PT Light absorbing member DP1 to DP3 Digital micromirror device DS Image display surface MR Micromirror MS Pixel reflection surface CG Cover glass P11 to P13 TIR prism P2 Color synthesis prism P3 Projection side prism L1 Illumination light L2 ON light (projection light) L3 OFF light (unnecessary light) AX1 Optical axis of illumination light AX2 Optical axis of projection light (ON light) AX3 Optical axis of OFF light MS2 ON reflection surface MS3 OFF reflection surface 1R, 1G, 1B Light source 2R, 2G, 2B Illumination optical system 3 Control unit 4 Actuator 12 Illumination light reflecting surface 51, 52 Lens AX Optical axis SC screen DR First dichroic coated surface DB Second dichroic coated surface

Abstract

An optical unit (PU) comprises a plurality of digital micro-mirror devices (DP), a plurality of TIR prisms (P1), and a color-compositing prism (P2). The TIR prisms (P1) are disposed between the digital micro-mirror devices (DP) and the color-compositing prism (P2). The color-compositing prism (P2) has a first dichroic coated surface (DR) and a second dichroic coated surface (DB) that reflect ON light having a prescribed wavelength and transmit ON light having wavelengths other than the prescribed wavelength. When each digital micro-mirror device (DP) is viewed from the normal line direction, the angle defined by the lengthwise direction of the digital micro-mirror device (DP) and the intersection line (S) of the first dichroic coated surface (DR) and the second dichroic surface (DB) is smaller than 45°.

Description

光学ユニット及びそれを備えたプロジェクターOptical unit and projector provided with the same
　本発明はデジタル・マイクロミラー・デバイスを有する光学ユニット及びそれを備えたプロジェクターに関する。 The present invention relates to an optical unit having a digital micromirror device and a projector including the same.
　従来の光学ユニットは特許文献１に開示されている。この光学ユニットはプロジェクターに搭載され、ＴＩＲプリズム、ダイクロイックプリズム及び複数のデジタル・マイクロミラー・デバイスを有する。投影側からデジタル・マイクロミラー・デバイスに向かってＴＩＲプリズム及びダイクロイックプリズムの順に配置されている。 A conventional optical unit is disclosed in Patent Document 1. The optical unit is mounted on a projector and includes a TIR prism, a dichroic prism, and a plurality of digital micromirror devices. A TIR prism and a dichroic prism are arranged in this order from the projection side toward the digital micromirror device.
　デジタル・マイクロミラー・デバイス(digital micromirror device)は平面視矩形の反射型画像表示素子であり、複数の微小なマイクロミラーから成る画像表示面を有する。デジタル・マイクロミラー・デバイスは各マイクロミラーの面の傾きをＯＮ／ＯＦＦ制御して照明光を強度変調することにより画像を形成する。各マイクロミラーはデジタル・マイクロミラー・デバイスの長手方向に対して直交する回動軸を中心に回動し、ＯＮ状態のマイクロミラーの傾き角度とＯＦＦ状態のマイクロミラーの傾き角度は異なっている。 A digital micromirror device is a reflection type image display element having a rectangular shape in plan view, and has an image display surface composed of a plurality of minute micromirrors. The digital micromirror device forms an image by controlling the intensity of illumination light by controlling the inclination of the surface of each micromirror. Each micromirror rotates about a rotation axis orthogonal to the longitudinal direction of the digital micromirror device, and the tilt angle of the micromirror in the ON state is different from the tilt angle of the micromirror in the OFF state.
　ＴＩＲプリズム（内部全反射プリズム：Total Internal Reflection Prism）は入射面から入射した白色の照明光を全反射面で全反射してダイクロイックプリズムに導く。 The TIR prism (Total Internal Reflection Prism) totally reflects the white illumination light incident from the incident surface to the dichroic prism.
　ダイクロイックプリズムは交差する２つのダイクロイックコート面を有し、ＴＩＲプリズムから出射された白色の照明光を赤色、緑色及び青色の照明光に分解して各デジタル・マイクロミラー・デバイスにそれぞれ導く。また、ダイクロイックプリズムは各デジタル・マイクロミラー・デバイスのＯＮ状態のマイクロミラーで反射した赤色、緑色及び青色のＯＮ光を色合成し、ＴＩＲプリズムに向けて出射する。 The dichroic prism has two dichroic coat surfaces that intersect, and separates the white illumination light emitted from the TIR prism into red, green, and blue illumination light and guides them to each digital micromirror device. The dichroic prism color-synthesizes red, green, and blue ON lights reflected by the ON micromirrors of each digital micromirror device, and emits them toward the TIR prism.
　なお、デジタル・マイクロミラー・デバイスの法線方向から見て、２つのダイクロイックコート面の交線が該デジタル・マイクロミラー・デバイスの長手方向に一致するように各デジタル・マイクロミラー・デバイスはダイクロイックプリズムに対向して配置される。 Each digital micromirror device is a dichroic prism so that the intersection of the two dichroic coat surfaces coincides with the longitudinal direction of the digital micromirror device when viewed from the normal direction of the digital micromirror device. It is arrange | positioned facing.
　ＴＩＲプリズムに入射した白色の照明光はダイクロイックプリズムにより分解され、赤色、緑色及び青色の各照明光が異なるデジタル・マイクロミラー・デバイスに入射する。各デジタル・マイクロミラー・デバイスのＯＮ状態のマイクロミラーで反射した赤色、緑色及び青色のＯＮ光はダイクロイックプリズムにより色合成され、ＴＩＲプリズムを介して投影側に射出される。これにより、カラー画像が投影される。 The white illumination light incident on the TIR prism is decomposed by the dichroic prism, and the red, green, and blue illumination lights enter different digital micromirror devices. The red, green, and blue ON lights reflected by the ON micromirrors of each digital micromirror device are color-combined by the dichroic prism and emitted to the projection side via the TIR prism. Thereby, a color image is projected.
特開２００７－２５２８７号公報（第６頁、第１図、第３図）JP 2007-25287 (page 6, FIGS. 1 and 3)
　上記従来の光学ユニットによると、照明光はＴＩＲプリズム及びダイクロイックプリズムの順に透過して各デジタル・マイクロミラー・デバイスに導かれる。この時、２つのダイクロイックコート面の交線に垂直な面に投影して、ダイクロイックプリズム内でＯＮ光の光軸と照明光の光軸とがずれている。このため、デジタル・マイクロミラー・デバイスの周縁部の所望のＦナンバーを確保するためにダイクロイックプリズムを大きくする必要があり、光学ユニットが大型化する問題があった。また、光学ユニットが大型化すると、プロジェクターの投影レンズのバックフォーカスを長く確保する必要があるため、投影レンズの設計の自由度が低くなる。このため、高性能な投影レンズを設計することが困難になる。 According to the above-described conventional optical unit, the illumination light is transmitted through the TIR prism and the dichroic prism in this order, and is guided to each digital micromirror device. At this time, the projection is performed on a plane perpendicular to the intersecting line of the two dichroic coat surfaces, and the optical axis of the ON light and the optical axis of the illumination light are shifted in the dichroic prism. For this reason, it is necessary to enlarge the dichroic prism in order to secure a desired F number at the peripheral portion of the digital micromirror device, and there is a problem that the optical unit becomes large. Further, when the optical unit is increased in size, it is necessary to ensure a long back focus of the projection lens of the projector, so that the degree of freedom in designing the projection lens is reduced. This makes it difficult to design a high-performance projection lens.
　本発明は、小型化できる光学ユニット及びそれを用いたプロジェクターを提供することを目的とする。 It is an object of the present invention to provide an optical unit that can be miniaturized and a projector using the same.
　上記目的を達成するために本発明は、回動軸を中心に回動する複数のマイクロミラーの各面の傾きがＯＮ／ＯＦＦ制御されて照明光を強度変調することにより画像を形成する平面視略矩形の複数のデジタル・マイクロミラー・デバイスと、
　各前記デジタル・マイクロミラー・デバイスに対応してそれぞれ設けられるとともに互いに波長の異なる照明光を各前記デジタル・マイクロミラー・デバイスに導く複数のＴＩＲプリズムと、
　各前記デジタル・マイクロミラー・デバイスのＯＮ状態の各前記マイクロミラーで反射されたＯＮ光を色合成して投影側に射出する色合成プリズムと、
　を備えた光学ユニットであって、
　前記デジタル・マイクロミラー・デバイスと前記色合成プリズムとの間に前記ＴＩＲプリズムを配置し、
　前記色合成プリズムは、所定波長のＯＮ光を反射して該所定波長以外のＯＮ光を透過する第１ダイクロイックコート面及び第２ダイクロイックコート面を有し、
　各前記デジタル・マイクロミラー・デバイスを法線方向から見て、第１ダイクロイックコート面と第２ダイクロイックコート面との交線と、該デジタル・マイクロミラー・デバイスの長手方向との成す角度が４５°よりも小さいことを特徴としている。 In order to achieve the above object, the present invention is a plan view in which an image is formed by intensity-modulating illumination light by controlling ON / OFF of the inclination of each surface of a plurality of micromirrors that rotate about a rotation axis. A plurality of substantially rectangular digital micromirror devices;
A plurality of TIR prisms provided corresponding to each of the digital micromirror devices and guiding illumination light having different wavelengths to each of the digital micromirror devices;
A color synthesizing prism that color-synthesizes the ON light reflected by each of the micromirrors in the ON state of each of the digital micromirror devices and emits the light to the projection side;
An optical unit comprising:
Placing the TIR prism between the digital micromirror device and the color combining prism;
The color synthesis prism has a first dichroic coating surface and a second dichroic coating surface that reflect ON light having a predetermined wavelength and transmit ON light having a wavelength other than the predetermined wavelength.
When each of the digital micromirror devices is viewed from the normal direction, an angle formed by an intersection line between the first dichroic coated surface and the second dichroic coated surface and a longitudinal direction of the digital micromirror device is 45 °. It is characterized by being smaller than.
　また本発明は、上記構成の光学ユニットにおいて、前記法線方向から見て、前記交線が前記長手方向に略一致すると好ましい。 In the optical unit configured as described above, it is preferable that the intersecting line substantially coincides with the longitudinal direction when viewed from the normal direction.
　また本発明は、上記構成の光学ユニットにおいて、前記回動軸が前記長手方向に対して４５°傾斜していると好ましい。 In the optical unit having the above-described configuration, it is preferable that the rotation shaft is inclined by 45 ° with respect to the longitudinal direction.
　また本発明は、上記構成の光学ユニットにおいて、前記回動軸が前記マイクロミラーの入射光の光軸方向に対して直交しないと好ましい。 Further, in the optical unit configured as described above, it is preferable that the rotation axis is not orthogonal to the optical axis direction of incident light of the micromirror.
　また本発明は、上記構成の光学ユニットにおいて、前記法線方向から見て、前記ＴＩＲプリズムの照明光反射面の法線が前記長手方向に対して傾斜すると好ましい。 In the optical unit configured as described above, it is preferable that the normal line of the illumination light reflecting surface of the TIR prism is inclined with respect to the longitudinal direction when viewed from the normal direction.
　また本発明は、上記構成の光学ユニットにおいて、前記ＴＩＲプリズムの照明光反射面のＯＮ光の光軸上の法線とＯＮ状態の前記マイクロミラーのＯＮ光の光軸上の法線とが同一平面上にあると好ましい。 According to the present invention, in the optical unit configured as described above, the normal line on the optical axis of the ON light of the illumination light reflecting surface of the TIR prism and the normal line on the optical axis of the ON light of the micromirror in the ON state are the same. It is preferable to be on a plane.
　また本発明は、上記構成の光学ユニットにおいて、前記ＴＩＲプリズムから出射される照明光が前記マイクロミラーに導かれ、前記マイクロミラーで反射したＯＮ光は前記ＴＩＲプリズム及び前記色合成プリズムの順に透過すると好ましい。 In the optical unit configured as described above, the illumination light emitted from the TIR prism is guided to the micromirror, and the ON light reflected by the micromirror is transmitted in the order of the TIR prism and the color combining prism. preferable.
　また本発明は、上記構成の光学ユニットにおいて、出射面の法線方向にＯＮ光の光軸が配される投影側プリズムを前記色合成プリズムの出射側に設けると好ましい。 In the optical unit configured as described above, it is preferable that a projection-side prism in which the optical axis of the ON light is arranged in the normal direction of the emission surface is provided on the emission side of the color synthesis prism.
　また本発明のプロジェクターは、上記構成の光学ユニットと、光源と、前記光学ユニットの各前記ＴＩＲプリズムに向けてそれぞれ波長の異なる照明光を出射する照明光学系と、前記デジタル・マイクロミラー・デバイスに表示された画像をスクリーンに拡大投影する投影光学系とを備えたことを特徴としている。 The projector of the present invention includes an optical unit configured as described above, a light source, an illumination optical system that emits illumination light having different wavelengths toward the TIR prisms of the optical unit, and the digital micromirror device. And a projection optical system for enlarging and projecting the displayed image on a screen.
　また本発明は、上記構成のプロジェクターにおいて、前記ＴＩＲプリズムの入射面の下方から照明光が入射すると好ましい。 In the projector having the above-described configuration, it is preferable that the illumination light is incident from below the incident surface of the TIR prism.
　本発明によると、各デジタル・マイクロミラー・デバイスを法線方向から見て、第１ダイクロイックコート面と第２ダイクロイックコートとの交線と、該デジタル・マイクロミラー・デバイスの長手方向との成す角度が４５°よりも小さい。これにより、ＯＮ光の像高を小さくすることができるため、色合成プリズムを小さくすることができる。この時、デジタル・マイクロミラー・デバイスと色合成プリズムとの間にＴＩＲプリズムを配置している。これにより、照明光を色合成プリズムを透過させずに各デジタル・マイクロミラー・デバイスに導くことができる。このため、色合成プリズムを小さくしてもデジタル・マイクロミラー・デバイスの周縁部の所望のＦナンバーを確保することができる。したがって、光学ユニット及びプロジェクターを小型化することができる。また、プロジェクターの投影光学系のバックフォーカスを短くすることができるため、投影光学系の設計の自由度を高くすることができる。これにより、高性能なプロジェクターを提供することができる。 According to the present invention, when each digital micromirror device is viewed from the normal direction, the angle formed by the line of intersection between the first dichroic coat surface and the second dichroic coat and the longitudinal direction of the digital micromirror device Is smaller than 45 °. Thereby, since the image height of ON light can be made small, a color composition prism can be made small. At this time, a TIR prism is disposed between the digital micromirror device and the color synthesis prism. As a result, the illumination light can be guided to each digital micromirror device without passing through the color synthesis prism. For this reason, even if the color synthesizing prism is made small, it is possible to secure a desired F number at the peripheral portion of the digital micromirror device. Therefore, the optical unit and the projector can be reduced in size. In addition, since the back focus of the projection optical system of the projector can be shortened, the degree of freedom in designing the projection optical system can be increased. Thereby, a high-performance projector can be provided.
本発明の第１実施形態の光学ユニットを備えるプロジェクターを示す概略構成図1 is a schematic configuration diagram showing a projector including an optical unit according to a first embodiment of the invention. 本発明の第１実施形態の光学ユニットを示す斜視図The perspective view which shows the optical unit of 1st Embodiment of this invention. 本発明の第１実施形態の光学ユニットを示す上面図The top view which shows the optical unit of 1st Embodiment of this invention. 本発明の第１実施形態の光学ユニットを示す側面断面図Side surface sectional drawing which shows the optical unit of 1st Embodiment of this invention. 本発明の第１実施形態の光学ユニットのデジタル・マイクロミラー・デバイスを示す正面図The front view which shows the digital micromirror device of the optical unit of 1st Embodiment of this invention 本発明の第１実施形態の他の例の光学ユニットのデジタル・マイクロミラー・デバイスを示す正面図The front view which shows the digital micromirror device of the optical unit of the other example of 1st Embodiment of this invention. 本発明の第１実施形態の光学ユニットのデジタル・マイクロミラー・デバイスの動作を説明するための斜視図The perspective view for demonstrating operation | movement of the digital micromirror device of the optical unit of 1st Embodiment of this invention. 本発明の第１実施形態の光学ユニットのＴＩＲプリズムを示す斜視図The perspective view which shows the TIR prism of the optical unit of 1st Embodiment of this invention. 本発明の第２実施形態の光学ユニットを備えるプロジェクターを示す概略構成図The schematic block diagram which shows a projector provided with the optical unit of 2nd Embodiment of this invention. 本発明の第２実施形態の光学ユニットを示す斜視図The perspective view which shows the optical unit of 2nd Embodiment of this invention. 本発明の第２実施形態の光学ユニットを示す上面図The top view which shows the optical unit of 2nd Embodiment of this invention. 本発明の第２実施形態の光学ユニットを示す側面断面図Side surface sectional drawing which shows the optical unit of 2nd Embodiment of this invention. 本発明の第３実施形態の光学ユニットを示す上面図The top view which shows the optical unit of 3rd Embodiment of this invention. 本発明の第３実施形態の光学ユニットを示す側面断面図Side surface sectional drawing which shows the optical unit of 3rd Embodiment of this invention. 本発明の第３実施形態の光学ユニットのデジタル・マイクロミラー・デバイスを示す正面図The front view which shows the digital micromirror device of the optical unit of 3rd Embodiment of this invention. 本発明の第４実施形態の光学ユニットを示す斜視図The perspective view which shows the optical unit of 4th Embodiment of this invention. 本発明の第４実施形態の光学ユニットを示す上面図The top view which shows the optical unit of 4th Embodiment of this invention.
　＜第１実施形態＞
　以下に本発明の実施形態を図面を参照して説明する。図１は第１実施形態の光学ユニットを備えるプロジェクターの概略構成図を示している。３チップタイプ（三板式）のプロジェクターＰＪは光源１Ｒ、１Ｇ、１Ｂ、照明光学系２Ｒ、２Ｇ、２Ｂ、光学ユニットＰＵ、投影光学系ＬＮ、アクチュエーター４及び制御部３を備える。なお、以下の説明において、光源１Ｒ、１Ｇ、１Ｂ及び照明光学系２Ｒ、２Ｇ、２Ｂを総称してそれぞれ「光源１」及び「照明光学系２」という場合がある。 <First Embodiment>
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram of a projector including the optical unit according to the first embodiment. The 3-chip type (three-plate type) projector PJ includes light sources 1R, 1G, and 1B, illumination optical systems 2R, 2G, and 2B, an optical unit PU, a projection optical system LN, an actuator 4, and a control unit 3. In the following description, the light sources 1R, 1G, and 1B and the illumination optical systems 2R, 2G, and 2B may be collectively referred to as “light source 1” and “illumination optical system 2”, respectively.
　光源１Ｒ、１Ｇ、１Ｂは赤色ＬＥＤ、緑色ＬＥＤ及び青色ＬＥＤをそれぞれ有し、それぞれ赤色光、緑色光及び青色光を出射する。照明光学系２Ｒ、２Ｇ、２Ｂはそれぞれ光源１Ｒ、１Ｇ、１Ｂに対応して設けられ、インテグレーター、リレーレンズ群及び反射ミラー等を有する（いずれも不図示）。照明光学系２は光源１の出射光を集光して照明光Ｌ１として光学ユニットＰＵに向けて出射する。 The light sources 1R, 1G, and 1B have red LEDs, green LEDs, and blue LEDs, respectively, and emit red light, green light, and blue light, respectively. The illumination optical systems 2R, 2G, and 2B are provided corresponding to the light sources 1R, 1G, and 1B, respectively, and include an integrator, a relay lens group, a reflection mirror, and the like (all not shown). The illumination optical system 2 condenses the light emitted from the light source 1 and emits the light toward the optical unit PU as illumination light L1.
　光学ユニットＰＵは平面視略矩形の複数のデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３、複数のＴＩＲプリズムＰ１１～Ｐ１３、１個の色合成プリズムＰ２及び１個の投影側プリズムＰ３を有し、支持部材（不図示）によりプロジェクターＰＪ内で支持される。光学ユニットＰＵはデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３（図３参照）で反射した投影光（後述のＯＮ光）を投影光学系ＬＮに向けて射出する。以下の説明において、デジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３及びＴＩＲプリズムＰ１１～Ｐ１３をそれぞれ総称して「デジタル・マイクロミラー・デバイスＤＰ」及び「ＴＩＲプリズムＰ１」という場合がある。なお、光学ユニットＰＵの詳細については後述する。 The optical unit PU has a plurality of digital micromirror devices DP1 to DP3 having a substantially rectangular shape in plan view, a plurality of TIR prisms P11 to P13, one color synthesis prism P2, and one projection side prism P3, and a support member. (Not shown) is supported in the projector PJ. The optical unit PU emits projection light (ON light described later) reflected by the digital micromirror devices DP1 to DP3 (see FIG. 3) toward the projection optical system LN. In the following description, the digital micromirror devices DP1 to DP3 and the TIR prisms P11 to P13 may be collectively referred to as “digital micromirror device DP” and “TIR prism P1”, respectively. Details of the optical unit PU will be described later.
　投影光学系ＬＮはレンズ５１、５２（図３参照）を有し、デジタル・マイクロミラー・デバイスＤＰ上に表示された画像をスクリーンＳＣに拡大投影する。アクチュエーター４はレンズ５１、５２を移動させ、例えばズーミングやフォーカシングを行う。制御部３はＣＰＵを有し、プロジェクターＰＪ全体の制御を行う。 The projection optical system LN has lenses 51 and 52 (see FIG. 3), and enlarges and projects an image displayed on the digital micromirror device DP onto the screen SC. The actuator 4 moves the lenses 51 and 52 to perform, for example, zooming or focusing. The control unit 3 has a CPU and controls the entire projector PJ.
　図２～図４は光学ユニットＰＵの斜視図、上面図及び側面断面図をそれぞれ示している。なお、図４はデジタル・マイクロミラー・デバイスＤＰ２を通る側面断面図を示している。図２～図４において、Ｘ方向は色合成プリズムＰ２の厚み方向を示している。Ｚ方向はデジタル・マイクロミラー・デバイスＤＰ２で反射した投影光（後述のＯＮ光）の光軸方向を示している。Ｙ方向はＸ方向及びＺ方向に垂直な方向を示している。 2 to 4 are a perspective view, a top view, and a side sectional view of the optical unit PU, respectively. FIG. 4 shows a side sectional view through the digital micromirror device DP2. 2 to 4, the X direction indicates the thickness direction of the color combining prism P2. The Z direction indicates the optical axis direction of the projection light (ON light described later) reflected by the digital micromirror device DP2. The Y direction indicates a direction perpendicular to the X direction and the Z direction.
　デジタル・マイクロミラー・デバイスＤＰ１と色合成プリズムＰ２との間、デジタル・マイクロミラー・デバイスＤＰ２と色合成プリズムＰ２との間、及びデジタル・マイクロミラー・デバイスＤＰ３と色合成プリズムＰ２との間には、それぞれＴＩＲプリズムＰ１１～Ｐ１３が配置される。これにより、ＴＩＲプリズムＰ１１～Ｐ１３はそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３に対応して設けられる。色合成プリズムＰ２の投影側には投影側プリズムＰ３が配される。 Between the digital micromirror device DP1 and the color synthesis prism P2, between the digital micromirror device DP2 and the color synthesis prism P2, and between the digital micromirror device DP3 and the color synthesis prism P2. TIR prisms P11 to P13 are respectively arranged. Thereby, the TIR prisms P11 to P13 are provided corresponding to the digital micromirror devices DP1 to DP3, respectively. A projection-side prism P3 is disposed on the projection side of the color synthesis prism P2.
　また、デジタル・マイクロミラー・デバイスＤＰとＴＩＲプリズムＰ１との間にはカバーガラスＣＧが設けられる。なお、図１及び図２ではカバーガラスＣＧの図示を省略している。 Also, a cover glass CG is provided between the digital micromirror device DP and the TIR prism P1. In addition, in FIG.1 and FIG.2, illustration of the cover glass CG is abbreviate | omitted.
　図５はデジタル・マイクロミラー・デバイスＤＰ２の正面図を示している。なお、デジタル・マイクロミラー・デバイスＤＰ１、ＤＰ３の構成もデジタル・マイクロミラー・デバイスＤＰ２の構成と同様であるため、デジタル・マイクロミラー・デバイスＤＰ２を代表して以下説明する。図５はデジタル・マイクロミラー・デバイスＤＰ２をＴＩＲプリズムＰ１２側から見た様子を示し、デジタル・マイクロミラー・デバイスＤＰ２のマイクロミラーＭＲを拡大して図示している。 FIG. 5 shows a front view of the digital micromirror device DP2. Since the configuration of the digital micromirror devices DP1 and DP3 is the same as that of the digital micromirror device DP2, the digital micromirror device DP2 will be described below as a representative. FIG. 5 shows a state in which the digital micromirror device DP2 is viewed from the TIR prism P12 side, and the micromirror MR of the digital micromirror device DP2 is enlarged.
　デジタル・マイクロミラー・デバイスＤＰ２はマトリクス状に配される平面視正方形の複数の微小なマイクロミラーＭＲを有する。マイクロミラーＭＲは略矩形の基板ＳＢ上に実装され、基板ＳＢは略矩形のハウジング（不図示）に収納される。マイクロミラーＭＲは基板ＳＢの長手方向（Ｙ方向）に対して４５°傾斜する回動軸ＲＡを中心に回動する。 The digital micromirror device DP2 has a plurality of micromirrors MR having a square shape in plan view arranged in a matrix. The micromirror MR is mounted on a substantially rectangular substrate SB, and the substrate SB is accommodated in a substantially rectangular housing (not shown). The micromirror MR rotates about a rotation axis RA inclined by 45 ° with respect to the longitudinal direction (Y direction) of the substrate SB.
　デジタル・マイクロミラー・デバイスＤＰ２の法線方向から見て、後述の色合成プリズムＰ２の第１ダイクロイックコート面ＤＲと第２ダイクロイックコートＤＢとの交線Ｓはデジタル・マイクロミラー・デバイスＤＰ２の長手方向（Ｙ方向）に略一致している。 When viewed from the normal direction of the digital micromirror device DP2, an intersection S between a first dichroic coat surface DR and a second dichroic coat DB of a color synthesizing prism P2 described later is the longitudinal direction of the digital micromirror device DP2. It almost coincides with (Y direction).
　なお、図６に示すように、デジタル・マイクロミラー・デバイスＤＰ２の法線方向から見て、交線Ｓとデジタル・マイクロミラー・デバイスＤＰ２の長手方向との成す角度θが４５°よりも小さくなるようにデジタル・マイクロミラー・デバイスＤＰ２をＴＩＲプリズムＰ１２に対向して配置してもよい。 As shown in FIG. 6, when viewed from the normal direction of the digital micromirror device DP2, the angle θ formed by the intersection line S and the longitudinal direction of the digital micromirror device DP2 is smaller than 45 °. As described above, the digital micromirror device DP2 may be arranged to face the TIR prism P12.
　図７はデジタル・マイクロミラー・デバイスＤＰ２のＯＮ状態及びＯＦＦ状態のマイクロミラーＭＲの斜視図を示している。マイクロミラーＭＲにより画素を構成する画素反射面（マイクロミラー面）ＭＳが形成される。マイクロミラーＭＲのＯＮ状態を反射面ＭＳ２で示し、マイクロミラーＭＲのＯＦＦ状態を反射面ＭＳ３で示している。マイクロミラーＭＲは基準状態（マイクロミラーＭＲの法線方向がＺ方向に一致している状態）から回動軸ＲＡを中心に－１２°回動してＯＮ状態になり、＋１２°回動してＯＦＦ状態になる。これにより、デジタル・マイクロミラー・デバイスＤＰ２は、複数の画素反射面ＭＳからなる画像表示面ＤＳにおいて、各画素反射面ＭＳがＯＮ／ＯＦＦ制御され、マイクロミラーＭＲが画像表示状態（ＯＮ状態）と画像非表示状態（ＯＦＦ状態）との２つの角度状態をとる。すなわち、デジタル・マイクロミラー・デバイスＤＰ２は回動軸ＲＡに関してマイクロミラーＭＲの駆動を行い、マイクロミラーＭＲは基準状態、ＯＮ状態及びＯＦＦ状態をとることができる。これにより、デジタル・マイクロミラー・デバイスＤＰ２は照明光Ｌ１を強度変調して所望の画像を生成する反射型画像表示素子を構成する。 FIG. 7 shows a perspective view of the micromirror MR in the ON state and OFF state of the digital micromirror device DP2. A pixel reflecting surface (micromirror surface) MS constituting a pixel is formed by the micromirror MR. The ON state of the micromirror MR is indicated by the reflecting surface MS2, and the OFF state of the micromirror MR is indicated by the reflecting surface MS3. The micromirror MR is turned on by rotating −12 ° around the rotation axis RA from the reference state (the normal direction of the micromirror MR coincides with the Z direction), and is turned + 12 °. It becomes OFF state. Thereby, in the digital micromirror device DP2, in the image display surface DS composed of a plurality of pixel reflection surfaces MS, each pixel reflection surface MS is ON / OFF controlled, and the micromirror MR is in an image display state (ON state). Two angle states are taken: an image non-display state (OFF state). That is, the digital micromirror device DP2 drives the micromirror MR with respect to the rotation axis RA, and the micromirror MR can take a reference state, an ON state, and an OFF state. Thus, the digital micromirror device DP2 constitutes a reflective image display element that generates a desired image by intensity-modulating the illumination light L1.
　本実施形態ではＯＮ状態及びＯＦＦ状態のマイクロミラーＭＲはＸＹ平面に対して傾斜している。通常想定されるＯＮ／ＯＦＦ制御では、画素反射面ＭＳがＯＮ状態のとき、マイクロミラーＭＲに入射した照明光Ｌ１は画像表示面ＤＳの法線方向に反射されてＯＮ光Ｌ２（投影光）となる。また、画素反射面ＭＳがＯＦＦ状態のとき、マイクロミラーＭＲに入射した照明光Ｌ１は画像表示面ＤＳの法線方向から大きな角度を持って反射され、ＯＦＦ光Ｌ３（不要光）となる。なお、照明光Ｌ１の光軸ＡＸ１、ＯＮ光Ｌ２の光軸ＡＸ２及びＯＦＦ光Ｌ３の光軸ＡＸ３（図４参照）は同一平面上に配される。 In the present embodiment, the micromirror MR in the ON state and the OFF state is inclined with respect to the XY plane. In the normally assumed ON / OFF control, when the pixel reflection surface MS is in the ON state, the illumination light L1 incident on the micromirror MR is reflected in the normal direction of the image display surface DS and is turned on with the ON light L2 (projection light). Become. When the pixel reflection surface MS is in the OFF state, the illumination light L1 incident on the micromirror MR is reflected with a large angle from the normal direction of the image display surface DS, and becomes OFF light L3 (unnecessary light). The optical axis AX1 of the illumination light L1, the optical axis AX2 of the ON light L2, and the optical axis AX3 (see FIG. 4) of the OFF light L3 are arranged on the same plane.
　以上のように、デジタル・マイクロミラー・デバイスＤＰ２の画像表示面ＤＳでは、照明光Ｌ１の強度変調により２次元画像が形成される。デジタル・マイクロミラー・デバイスＤＰ２は、前述したように１軸に関してマイクロミラーＭＲの駆動を行うことによりＯＮ／ＯＦＦを表現する。 As described above, on the image display surface DS of the digital micromirror device DP2, a two-dimensional image is formed by intensity modulation of the illumination light L1. The digital micromirror device DP2 expresses ON / OFF by driving the micromirror MR about one axis as described above.
　図２～図４に戻って、ＴＩＲプリズムＰ１、色合成プリズムＰ２及び投影側プリズムＰ３について説明する。ＴＩＲプリズムＰ１は２個のプリズムから構成され、入射面１１、照明光反射面１２及び出射面１３、１４、１５を有する。入射面１１はデジタル・マイクロミラー・デバイスＤＰの短手方向に対して約４５°傾斜し、照明光学系２から出射された照明光Ｌ１を入射する。本実施形態ではＴＩＲプリズムＰ１１～Ｐ１３の入射面１１にはそれぞれ赤色、緑色及び青色の照明光Ｌ１が入射する。すなわち、ＴＩＲプリズムＰ１１～Ｐ１３の入射面１１には互いに波長の異なる照明光Ｌ１がそれぞれ入射する。 2 to 4, the TIR prism P1, the color synthesis prism P2, and the projection side prism P3 will be described. The TIR prism P1 is composed of two prisms and has an incident surface 11, an illumination light reflecting surface 12, and exit surfaces 13, 14, and 15. The incident surface 11 is inclined by about 45 ° with respect to the short direction of the digital micromirror device DP, and enters the illumination light L 1 emitted from the illumination optical system 2. In this embodiment, red, green, and blue illumination light L1 is incident on the incident surfaces 11 of the TIR prisms P11 to P13, respectively. That is, illumination lights L1 having different wavelengths are incident on the incident surfaces 11 of the TIR prisms P11 to P13.
　図８はＴＩＲプリズムＰ１２の斜視図を示している。なお、ＴＩＲプリズムＰ１１、Ｐ１３の構成もＴＩＲプリズムＰ１２の構成と同様であるため、ＴＩＲプリズムＰ１２を代表して以下説明する。照明光反射面１２は照明光学系２（図１参照）から離れるほどデジタル・マイクロミラー・デバイスＤＰ２に近づくように傾斜し、入射面１１から入射した照明光Ｌ１をデジタル・マイクロミラー・デバイスＤＰ２に向けて全反射する。デジタル・マイクロミラー・デバイスＤＰ２の法線ＮＤ方向から見て、照明光反射面１２の法線Ｎ１２はデジタル・マイクロミラー・デバイスＤＰ２の長手方向（Ｙ方向）に対して傾斜している。これにより、ＴＩＲプリズムＰ１２は照明光Ｌ１をデジタル・マイクロミラー・デバイスＤＰ２に効率良く導くことができる。 FIG. 8 shows a perspective view of the TIR prism P12. Since the TIR prisms P11 and P13 have the same configuration as the TIR prism P12, the TIR prism P12 will be described below as a representative. The illumination light reflecting surface 12 is inclined so as to approach the digital micromirror device DP2 as the distance from the illumination optical system 2 (see FIG. 1) increases, and the illumination light L1 incident from the incident surface 11 enters the digital micromirror device DP2. Total reflection toward. When viewed from the normal ND direction of the digital micromirror device DP2, the normal N12 of the illumination light reflecting surface 12 is inclined with respect to the longitudinal direction (Y direction) of the digital micromirror device DP2. Thereby, the TIR prism P12 can efficiently guide the illumination light L1 to the digital micromirror device DP2.
　また、ＴＩＲプリズムＰ１の照明光反射面１２のＯＮ光Ｌ２の光軸ＡＸ２上の法線と該ＴＩＲプリズムＰ１に対応するＯＮ状態のマイクロミラーＭＲのＯＮ光Ｌ２の光軸ＡＸ２上の法線とは同一平面上にある。 The normal line on the optical axis AX2 of the ON light L2 of the illumination light reflecting surface 12 of the TIR prism P1 and the normal line on the optical axis AX2 of the ON light L2 of the micromirror MR in the ON state corresponding to the TIR prism P1 Are on the same plane.
　出射面１３はデジタル・マイクロミラー・デバイスＤＰのカバーグラスＣＧ（図３、図４参照）に対向し、照明光反射面１２で全反射した照明光Ｌ１をデジタル・マイクロミラー・デバイスＤＰ２に向けて出射する。出射面１４は色合成プリズムＰ２に対向し、デジタル・マイクロミラー・デバイスＤＰ２で反射したＯＮ光Ｌ２を出射する。出射面１５はＯＮ光Ｌ２の光軸ＡＸ２に対して入射面１１と反対側の端面（Ｙ方向の端面）により形成され、ＯＦＦ光Ｌ３を出射する。 The exit surface 13 faces the cover glass CG (see FIGS. 3 and 4) of the digital micromirror device DP, and the illumination light L1 totally reflected by the illumination light reflecting surface 12 is directed toward the digital micromirror device DP2. Exit. The emission surface 14 faces the color synthesis prism P2, and emits the ON light L2 reflected by the digital micromirror device DP2. The exit surface 15 is formed by an end surface (end surface in the Y direction) opposite to the entrance surface 11 with respect to the optical axis AX2 of the ON light L2, and emits the OFF light L3.
　色合成プリズムＰ２は所謂フィリップスタイプのダイクロイックプリズムから成り、３個のプリズムＰ２１～Ｐ２３から成る。ＴＩＲプリズムＰ１２から投影光学系ＬＮに向かってプリズムＰ２２、Ｐ２３、Ｐ２１の順に配置される。プリズムＰ２１～Ｐ２３はそれぞれ入射面２１を有し、各入射面２１はそれぞれＴＩＲプリズムＰ１１～Ｐ１３の出射面１４に対向している。プリズムＰ２１、Ｐ２３はそれぞれ全反射面２２を有するとともにそれぞれ第１ダイクロイックコート面ＤＲ及び第２ダイクロイックコート面ＤＢを有する。プリズムＰ２１の投影側には色合成されたＯＮ光Ｌ２を出射する出射面２３が形成される。 The color synthesizing prism P2 includes a so-called Philips type dichroic prism, and includes three prisms P21 to P23. The prisms P22, P23, and P21 are arranged in this order from the TIR prism P12 toward the projection optical system LN. Each of the prisms P21 to P23 has an entrance surface 21, and each entrance surface 21 faces the exit surface 14 of each of the TIR prisms P11 to P13. The prisms P21 and P23 each have a total reflection surface 22, and each have a first dichroic coating surface DR and a second dichroic coating surface DB. On the projection side of the prism P21, an emission surface 23 for emitting the color-combined ON light L2 is formed.
　第１ダイクロイックコート面ＤＲ及びプリズムＰ２３の全反射面２２はＴＩＲプリズムＰ１１から離れるほどデジタル・マイクロミラー・デバイスＤＰ２から離れるように傾斜している。第２ダイクロイックコート面ＤＢ及びプリズムＰ２１の全反射面２２はＴＩＲプリズムＰ１１から離れるほどデジタル・マイクロミラー・デバイスＤＰ２に近づくように傾斜している。第１ダイクロイックコート面ＤＲと第２ダイクロイックコート面ＤＢとの交線Ｓ（図２、図５参照）はＹ方向に延びている。 The first dichroic coat surface DR and the total reflection surface 22 of the prism P23 are inclined so as to be separated from the digital micromirror device DP2 as the distance from the TIR prism P11 is increased. The second dichroic coating surface DB and the total reflection surface 22 of the prism P21 are inclined so as to approach the digital micromirror device DP2 as the distance from the TIR prism P11 increases. An intersection line S (see FIGS. 2 and 5) between the first dichroic coat surface DR and the second dichroic coat surface DB extends in the Y direction.
　第１ダイクロイックコート面ＤＲは赤色のＯＮ光Ｌ２を反射するとともに、緑色及び青色のＯＮ光Ｌ２を透過させる。第２ダイクロイックコート面ＤＢは青色のＯＮ光Ｌ２を反射するとともに緑色のＯＮ光Ｌ２を透過させる。すなわち、第１ダイクロイックコート面ＤＲ及び第２ダイクロイックコート面ＤＢは所定波長のＯＮ光Ｌ２を反射して該所定波長以外のＯＮ光Ｌ２を透過する。これにより、色合成プリズムＰ２はＴＩＲプリズムＰ１１～Ｐ１３からそれぞれ出射された赤色、緑色及び青色のＯＮ光Ｌ２を色合成して投影側に出射する。 The first dichroic coat surface DR reflects the red ON light L2 and transmits the green and blue ON light L2. The second dichroic coat surface DB reflects the blue ON light L2 and transmits the green ON light L2. That is, the first dichroic coated surface DR and the second dichroic coated surface DB reflect the ON light L2 having a predetermined wavelength and transmit the ON light L2 having a wavelength other than the predetermined wavelength. As a result, the color combining prism P2 color-synthesizes the red, green and blue ON lights L2 emitted from the TIR prisms P11 to P13, respectively, and emits them to the projection side.
　なお、プリズムＰ２１とプリズムＰ２３とを入れ替えて配置してもよい。すなわち、プリズムＰ２３をプリズムＰ２１よりも投影側に配置してもよい。また、所謂フィリップスタイプのダイクロイックプリズムに替えて、クロスダイクロイックプリズムにより色合成プリズムＰ２を形成してもよい。 Note that the prism P21 and the prism P23 may be interchanged. That is, the prism P23 may be disposed on the projection side with respect to the prism P21. Further, instead of the so-called Philips type dichroic prism, the color synthesis prism P2 may be formed by a cross dichroic prism.
　投影側プリズムＰ３は色合成プリズムＰ２の出射側に配され、入射面３１及び出射面３２を有する。入射面３１はＴＩＲプリズムＰ１１から離れるほどデジタル・マイクロミラー・デバイスＤＰ２に近づくように傾斜し、色合成プリズムＰ２を透過して出射面２３から出射されたＯＮ光Ｌ２（色合成後の投影光）を入射する。出射面３２は投影光学系ＬＮに対向して配され、ＯＮ光Ｌ２の光軸ＡＸ２が出射面３２の法線方向に一致するようにＯＮ光Ｌ２を出射する。投影側プリズムＰ３によりスクリーンＳＣに投影される画像の歪みを低減することができる。また、ＴＩＲプリズムＰ１１、Ｐ１３の投影光学系ＬＮ側の端部は投影側プリズムＰ３の出射面３２に対して出射側に突出している。 The projection-side prism P3 is disposed on the exit side of the color synthesis prism P2, and has an entrance surface 31 and an exit surface 32. The incident surface 31 is inclined so as to be closer to the digital micromirror device DP2 as it is farther from the TIR prism P11, and is transmitted through the color synthesis prism P2 and emitted from the emission surface 23 (projected light after color synthesis). Is incident. The exit surface 32 is arranged to face the projection optical system LN, and emits the ON light L2 so that the optical axis AX2 of the ON light L2 coincides with the normal direction of the exit surface 32. The distortion of the image projected on the screen SC by the projection side prism P3 can be reduced. Further, the end portions of the TIR prisms P11 and P13 on the projection optical system LN side protrude toward the emission side with respect to the emission surface 32 of the projection side prism P3.
　ＴＩＲプリズムＰ１、色合成プリズムＰ２及び投影側プリズムＰ３の材質として例えばガラスを用いることができる。本実施形態では、ＴＩＲプリズムＰ１、色合成プリズムＰ２及び投影側プリズムＰ３は屈折率が同じガラスにより形成される。支持部材は光学ユニットＰＵの上下面（色合成プリズムＰ２のＹ方向の両端面）に接して配され、光学ユニットＰＵを挟持する。 For example, glass can be used as the material of the TIR prism P1, the color synthesis prism P2, and the projection side prism P3. In the present embodiment, the TIR prism P1, the color synthesis prism P2, and the projection side prism P3 are made of glass having the same refractive index. The support members are arranged in contact with the upper and lower surfaces of the optical unit PU (both end surfaces in the Y direction of the color combining prism P2), and sandwich the optical unit PU.
　また、ＴＩＲプリズムＰ１と色合成プリズムＰ２との間、色合成プリズムＰ２と投影側プリズムＰ３との間にはエアーギャップ（不図示）が設けられる。また、ＴＩＲプリズムＰ１内の複数のプリズム間及び色合成プリズムＰ２内のプリズムＰ２１～Ｐ２３間にもエアーギャップ（不図示）が設けられる。 Further, an air gap (not shown) is provided between the TIR prism P1 and the color combining prism P2, and between the color combining prism P2 and the projection side prism P3. An air gap (not shown) is also provided between the plurality of prisms in the TIR prism P1 and between the prisms P21 to P23 in the color synthesis prism P2.
　また、色合成プリズムＰ２のＹ方向の端面（上面）に離れて対向して光吸収部材ＰＴが設けられる。光吸収部材ＰＴは例えば黒色処理した金属プレートにより形成され、ＴＩＲプリズムＰ１の出射面１５から出射されたＯＦＦ光Ｌ３を吸収する。これにより、光学ユニットＰＵから出射されたＯＦＦ光Ｌ３によるプロジェクターＰＪ内の他の部材等の熱変形を防止することができる。 Also, a light absorbing member PT is provided facing away from the end face (upper surface) in the Y direction of the color combining prism P2. The light absorbing member PT is formed of, for example, a black-treated metal plate, and absorbs the OFF light L3 emitted from the emission surface 15 of the TIR prism P1. Thereby, it is possible to prevent thermal deformation of other members in the projector PJ due to the OFF light L3 emitted from the optical unit PU.
　上記構成のプロジェクターＰＪにおいて、光源１Ｒ、１Ｇ、１Ｂ（図１参照）からそれぞれ赤色光、緑色光及び青色光が出射されると、それぞれ照明光学系２Ｒ、２Ｇ、２Ｂで集光されてそれぞれ赤色、緑色及び青色の照明光Ｌ１が光学ユニットＰＵに向けて出射される。 In the projector PJ having the above configuration, when red light, green light, and blue light are emitted from the light sources 1R, 1G, and 1B (see FIG. 1), respectively, they are condensed by the illumination optical systems 2R, 2G, and 2B, respectively, and red. The green and blue illumination light L1 is emitted toward the optical unit PU.
　赤色、緑色及び青色の照明光Ｌ１はそれぞれＴＩＲプリズムＰ１１～Ｐ１３の入射面１１に入射した後に照明光反射面１２で全反射する。照明光反射面１２で全反射した赤色、緑色及び青色の照明光Ｌ１は出射面１３から出射した後に、カバーガラスＣＧを透過してそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３に入射する。ＴＩＲプリズムＰ１１～Ｐ１３によって、互いに波長の異なる照明光Ｌ１が色合成プリズムＰ２を透過せずにそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３に導かれる。この時、回動軸ＲＡはマイクロミラーＭＲの入射光の光軸方向に対して直交していないため、照明光Ｌ１をデジタル・マイクロミラー・デバイスＰ１に効率良く導くことができる。 The red, green, and blue illumination light L1 is incident on the incident surface 11 of each of the TIR prisms P11 to P13 and then totally reflected by the illumination light reflecting surface 12. The red, green, and blue illumination lights L1 totally reflected by the illumination light reflecting surface 12 are emitted from the emission surface 13, and then pass through the cover glass CG and enter the digital micromirror devices DP1 to DP3, respectively. The TIR prisms P11 to P13 guide the illumination lights L1 having different wavelengths to the digital micromirror devices DP1 to DP3, respectively, without passing through the color synthesis prism P2. At this time, since the rotation axis RA is not orthogonal to the optical axis direction of the incident light of the micromirror MR, the illumination light L1 can be efficiently guided to the digital micromirror device P1.
　デジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３のＯＮ状態のマイクロミラーＭＲでそれぞれ反射した赤色、緑色及び青色のＯＮ光Ｌ２は照明光反射面１２を透過した後にそれぞれ入射面２１を介して色合成プリズムＰ２に入射する。赤色のＯＮ光Ｌ２はプリズムＰ２１の全反射面２２で全反射した後に第１ダイクロイックコート面ＤＲで反射して出射面２３に向かう。緑色のＯＮ光Ｌ２はプリズムＰ２２を透過した後に第２ダイクロイックコート面ＤＢ及び第１ダイクロイックコート面ＤＲの順に透過して出射面２３に向かう。青色のＯＮ光Ｌ２はプリズムＰ２３の全反射面２２で全反射した後に第２ダイクロイックコート面ＤＢで反射し、第１ダイクロイックコート面ＤＲを透過して出射面２３に向かう。この時、各色のＯＮ光Ｌ２は色合成プリズムＰ２を透過する間に色合成され、色合成されたＯＮ光Ｌ２が出射面２３から投影側に出射される。 The red, green, and blue ON lights L2 reflected by the micromirrors MR in the ON state of the digital micromirror devices DP1 to DP3 are transmitted through the illumination light reflecting surface 12 and then each color combining prism P2 via the incident surface 21. Is incident on. The red ON light L <b> 2 is totally reflected by the total reflection surface 22 of the prism P <b> 21, then reflected by the first dichroic coat surface DR, and directed toward the emission surface 23. The green ON light L <b> 2 passes through the prism P <b> 22 and then passes through the second dichroic coat surface DB and the first dichroic coat surface DR in this order and travels toward the exit surface 23. The blue ON light L2 is totally reflected by the total reflection surface 22 of the prism P23, then reflected by the second dichroic coat surface DB, passes through the first dichroic coat surface DR, and travels toward the emission surface 23. At this time, the ON light L2 of each color is color-synthesized while passing through the color synthesis prism P2, and the color-synthesized ON light L2 is emitted from the emission surface 23 to the projection side.
　色合成プリズムＰ２の出射面２３から出射されたＯＮ光Ｌ２は出射面３１を介して投影側プリズムＰ３に入射する。投影側プリズムＰ３に入射したＯＮ光Ｌ２は投影側プリズムＰ３を透過して出射面３２から投影光学系ＬＮに向けて出射される。 The ON light L2 emitted from the emission surface 23 of the color synthesis prism P2 enters the projection-side prism P3 via the emission surface 31. The ON light L2 incident on the projection side prism P3 passes through the projection side prism P3 and is emitted from the emission surface 32 toward the projection optical system LN.
　投影光学系ＬＮに入射したＯＮ光Ｌ２はスクリーンＳＣ（図１参照）に投射される。これにより、デジタル・マイクロミラー・デバイスＤＰに表示されたカラー画像はスクリーンＳＣに拡大投影される。この時、アクチュエーター４によりズーミングやフォーカシングが行われる。また、投影側プリズムＰ３は光軸ＡＸ２が出射面３２の法線方向に一致するように出射面３２からＯＮ光Ｌ２を出射する。これにより、スクリーンＳＣに拡大投影される画像の歪みを低減することができる。 The ON light L2 incident on the projection optical system LN is projected on the screen SC (see FIG. 1). As a result, the color image displayed on the digital micromirror device DP is enlarged and projected on the screen SC. At this time, zooming and focusing are performed by the actuator 4. The projection-side prism P3 emits the ON light L2 from the emission surface 32 so that the optical axis AX2 coincides with the normal direction of the emission surface 32. Thereby, distortion of the image enlarged and projected on the screen SC can be reduced.
　一方、デジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３のＯＦＦ状態のマイクロミラーＭＲで反射したＯＦＦ光Ｌ３は出射面１５から出射され、光学ユニットＰＵの外部へ排出される。光学ユニットＰＵから排出されたＯＦＦ光Ｌ３は光吸収部材ＰＴ（図４参照）により吸収される。これにより、ＯＦＦ光Ｌ３の投影光学系ＬＮへの入射を防止することができる。したがって、投影画像のコントラストの低下を防止することができる。 On the other hand, the OFF light L3 reflected by the micromirror MR in the OFF state of the digital micromirror devices DP1 to DP3 is emitted from the emission surface 15 and is emitted to the outside of the optical unit PU. The OFF light L3 emitted from the optical unit PU is absorbed by the light absorbing member PT (see FIG. 4). Thereby, it is possible to prevent the OFF light L3 from entering the projection optical system LN. Accordingly, it is possible to prevent the contrast of the projected image from being lowered.
　この時、光吸収部材ＰＴは出射面１５から離れて設けられている。これにより、ＯＦＦ光Ｌ３を吸収した光吸収部材ＰＴの熱の光学ユニットＰＵへの伝熱を低減することができる。したがって、光学ユニットＰＵの温度上昇を抑え、光学ユニットＰＵの熱変形等を防止することができる。その結果、光学ユニットＰＵ及びプロジェクターＰＪの長寿命化を図ることができる。 At this time, the light absorbing member PT is provided apart from the emission surface 15. Thereby, the heat transfer to the optical unit PU of the heat | fever of the light absorption member PT which absorbed OFF light L3 can be reduced. Therefore, the temperature rise of the optical unit PU can be suppressed, and thermal deformation or the like of the optical unit PU can be prevented. As a result, the lifetime of the optical unit PU and the projector PJ can be extended.
　なお、ＯＮ状態及びＯＦＦ状態の一方から他方へ移行中のマイクロミラーＭＲで反射した照明光Ｌ１（フラット光）はマイクロミラーＭＲの法線方向に対して照明光Ｌ１の入射光とは反対方向へ反射される。フラット光やカバーガラスＣＧでの照明光Ｌ１の反射光もＴＩＲプリズムＰ１に入射し、その後に出射面１５から出射される。これにより、フラット光やカバーガラスＣＧでの照明光Ｌ１の反射光の投影光学系ＬＮへの入射を防止することができる。したがって、投影画像のコントラストの低下を一層防止することができる。 The illumination light L1 (flat light) reflected by the micromirror MR that is transitioning from one of the ON state and the OFF state to the other is in a direction opposite to the incident light of the illumination light L1 with respect to the normal direction of the micromirror MR. Reflected. The reflected light of the illumination light L1 from the flat light or the cover glass CG is also incident on the TIR prism P1, and is then emitted from the emission surface 15. Thereby, it is possible to prevent the reflected light of the illumination light L1 from the flat light or the cover glass CG from entering the projection optical system LN. Therefore, it is possible to further prevent the contrast of the projected image from decreasing.
　また、デジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３をそれぞれの法線ＮＤ方向から見て、第１ダイクロイックコート面ＤＲと第２ダイクロイックコート面ＤＢとの交線Ｓがそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３の長手方向（Ｙ方向）と略一致している。これにより、ＯＮ光Ｌ２の像高を小さくすることができ、色合成プリズムＰ２のＺ方向の長さを短くすることができる。この時、デジタル・マイクロミラー・デバイスＤＰと色合成プリズムＰ２との間にＴＩＲプリズムＰ１を配置している。これにより、照明光Ｌ１は色合成プリズムＰ２を透過せずにＴＩＲプリズムＰ１を透過してデジタル・マイクロミラー・デバイスＤＰに導かれる。このため、色合成プリズムＰ２のＺ方向の幅を小さくしても、デジタル・マイクロミラー・デバイスＤＰの周縁部の所望のＦナンバーを確保することができる。したがって、光学ユニットＰＵを小型化し、投影光学系ＬＮのバックフォーカスＢＦ（レンズ５２の最後端から画像表示面ＤＳまでの距離）を短くすることができ、プロジェクターＰＪを小型化することができる。 Further, when the digital micromirror devices DP1 to DP3 are viewed from the respective normal ND directions, the intersection lines S of the first dichroic coated surface DR and the second dichroic coated surface DB are respectively represented by the digital micromirror devices DP1 to DP3. It substantially coincides with the longitudinal direction (Y direction) of DP3. Thereby, the image height of the ON light L2 can be reduced, and the length of the color combining prism P2 in the Z direction can be shortened. At this time, the TIR prism P1 is disposed between the digital micromirror device DP and the color synthesis prism P2. As a result, the illumination light L1 passes through the TIR prism P1 without passing through the color synthesis prism P2, and is guided to the digital micromirror device DP. For this reason, even if the width of the color synthesizing prism P2 in the Z direction is reduced, it is possible to secure a desired F number at the peripheral edge of the digital micromirror device DP. Therefore, the optical unit PU can be downsized, the back focus BF (distance from the rear end of the lens 52 to the image display surface DS) of the projection optical system LN can be shortened, and the projector PJ can be downsized.
　本実施形態の光学ユニットＰＵの色合成プリズムＰ２及び比較例の光学ユニットの色合成プリズムのＺ方向の長さを比較した。比較例ではデジタル・マイクロミラー・デバイスＤＰの法線方向から見てデジタル・マイクロミラー・デバイスＤＰの長手方向と交線Ｓとの成す角度θ（図６参照）を４５°にしている。また、比較例では本実施形態のＴＩＲプリズムＰ１１～Ｐ１３を省き、１個のＴＩＲプリズムを色合成プリズムの出射側に配置した。比較例のその他の構成は光学ユニットＰＵと同様にした。また、本実施形態及び比較例では短手方向及び長手方向の長さがそれぞれ約１６．３ｍｍ及び約３１．０ｍｍのデジタル・マイクロミラー・デバイスＤＰを用いて、デジタル・マイクロミラー・デバイスＤＰの周縁部のＦナンバーを同じにした。 The lengths in the Z direction of the color synthesis prism P2 of the optical unit PU of the present embodiment and the color synthesis prism of the optical unit of the comparative example were compared. In the comparative example, the angle θ (see FIG. 6) formed between the longitudinal direction of the digital micromirror device DP and the intersection line S as viewed from the normal direction of the digital micromirror device DP is set to 45 °. In the comparative example, the TIR prisms P11 to P13 of this embodiment are omitted, and one TIR prism is arranged on the output side of the color synthesis prism. Other configurations of the comparative example were the same as those of the optical unit PU. In this embodiment and the comparative example, the digital micromirror device DP having a length in the short-side direction and a lengthwise direction of about 16.3 mm and about 31.0 mm is used, and the periphery of the digital micromirror device DP is used. The F number of the part was made the same.
　比較例の色合成プリズムのＺ方向の長さは約８２．５ｍｍであるのに対し、本実施形態の光学ユニットＰＵのＺ方向の長さは約７６．１ｍｍであり、本実施形態の光学ユニットＰＵの色合成プリズムＰ２のＺ方向の長さは比較例よりも約６．４ｍｍ短くなる。したがって、本実施形態の光学ユニットＰＵを備えたプロジェクターＰＪのバックフォーカスＢＦを比較例の場合よりも短くすることができる。なお、照明光Ｌ１が色合成プリズムＰ２を透過しないため照明光Ｌ１の光路を短くすることができ、ＴＩＲプリズムＰ１を比較例のＴＩＲプリズムよりも小型化することができる。 The length of the comparative color synthesizing prism in the Z direction is about 82.5 mm, whereas the length of the optical unit PU of the present embodiment in the Z direction is about 76.1 mm. The length of the PU color synthesis prism P2 in the Z direction is about 6.4 mm shorter than that of the comparative example. Therefore, the back focus BF of the projector PJ including the optical unit PU of the present embodiment can be made shorter than that in the comparative example. Since the illumination light L1 does not pass through the color synthesis prism P2, the optical path of the illumination light L1 can be shortened, and the TIR prism P1 can be made smaller than the TIR prism of the comparative example.
　本実施形態によると、デジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３をそれぞれの法線ＮＤ方向から見て、第１ダイクロイックコート面ＤＲと第２ダイクロイックコート面ＤＢとの交線Ｓがそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３の長手方向（Ｙ方向）と略一致している。これにより、ＯＮ光Ｌ２の像高を小さくすることができ、色合成プリズムＰ２のＺ方向の長さを短くすることができる。この時、デジタル・マイクロミラー・デバイスＤＰと色合成プリズムＰ２との間にＴＩＲプリズムＰ１を配置している。これにより、照明光Ｌ１は色合成プリズムＰ２を透過せずにＴＩＲプリズムＰ１を透過してデジタル・マイクロミラー・デバイスＤＰに導かれる。このため、色合成プリズムＰ２のＺ方向の幅を小さくしても、デジタル・マイクロミラー・デバイスＤＰの周縁部の所望のＦナンバーを確保することができる。したがって、光学ユニットＰＵを小型化し、投影光学系ＬＮのバックフォーカスＢＦ（レンズ５２の最後端から画像表示面ＤＳまでの距離）を短くすることができ、プロジェクターＰＪを小型化することができる。 According to the present embodiment, when the digital micromirror devices DP1 to DP3 are viewed from the respective normal ND directions, the intersection lines S between the first dichroic coated surface DR and the second dichroic coated surface DB are respectively digital micromirrors. -It substantially coincides with the longitudinal direction (Y direction) of the devices DP1 to DP3. Thereby, the image height of the ON light L2 can be reduced, and the length of the color combining prism P2 in the Z direction can be shortened. At this time, the TIR prism P1 is disposed between the digital micromirror device DP and the color synthesis prism P2. As a result, the illumination light L1 passes through the TIR prism P1 without passing through the color synthesis prism P2, and is guided to the digital micromirror device DP. For this reason, even if the width of the color synthesizing prism P2 in the Z direction is reduced, it is possible to secure a desired F number at the peripheral edge of the digital micromirror device DP. Therefore, the optical unit PU can be downsized, the back focus BF (distance from the rear end of the lens 52 to the image display surface DS) of the projection optical system LN can be shortened, and the projector PJ can be downsized.
　また、プロジェクターＰＪの投影光学系ＬＮのバックフォーカスＢＦを短くすることができるため、投影レンズ５１、５２の設計の自由度を高くすることができる。これにより、高性能なプロジェクターＰＪを提供することができる。 Further, since the back focus BF of the projection optical system LN of the projector PJ can be shortened, the design freedom of the projection lenses 51 and 52 can be increased. Thereby, a high-performance projector PJ can be provided.
　なお、法線ＮＤ方向から見て、交線Ｓとデジタル・マイクロミラー・デバイスＤＰの長手方向との成す角度θ（図６参照）が４５°よりも小さければ、ＯＮ光Ｌ２の像高を小さくすることができる。このため、色合成プリズムＰ２のＺ方向の長さを短くしてバックフォーカスＢＦを短くすることができる。交線Ｓがデジタル・マイクロミラー・デバイスＤＰの長手方向に略一致するとバックフォーカスＢＦをさらに短くできるためより望ましい。 If the angle θ (see FIG. 6) formed by the intersecting line S and the longitudinal direction of the digital micromirror device DP is smaller than 45 ° when viewed from the normal ND direction, the image height of the ON light L2 is reduced. can do. For this reason, the back focus BF can be shortened by shortening the length of the color synthesis prism P2 in the Z direction. It is more desirable that the intersection line S substantially coincides with the longitudinal direction of the digital micromirror device DP because the back focus BF can be further shortened.
　また、マイクロミラーＭＲの回動軸ＲＡがデジタル・マイクロミラー・デバイスＤＰの長手方向に対して４５°傾斜している。これにより、汎用されているデジタル・マイクロミラー・デバイスＤＰを用いることができ、光学ユニットＰＵ及びプロジェクターＰＪの製造コストを削減することができる。 Also, the rotation axis RA of the micromirror MR is inclined 45 ° with respect to the longitudinal direction of the digital micromirror device DP. As a result, a general-purpose digital micromirror device DP can be used, and the manufacturing costs of the optical unit PU and the projector PJ can be reduced.
　また、回動軸ＲＡがマイクロミラーＭＲの入射光の光軸方向に対して直交しないため、デジタル・マイクロミラー・デバイスＤＰで反射したＯＮ光Ｌ２を効率良く投影側に向けて出射することができる。 Further, since the rotation axis RA is not orthogonal to the optical axis direction of the incident light of the micromirror MR, the ON light L2 reflected by the digital micromirror device DP can be efficiently emitted toward the projection side. .
　また、デジタル・マイクロミラー・デバイスＤＰの法線ＮＤ方向から見て、ＴＩＲプリズムＰ１の照明光反射面１２の法線Ｎ１２がデジタル・マイクロミラー・デバイスＤＰの長手方向に対して傾斜している。これにより、デジタル・マイクロミラー・デバイスＤＰに効率良く照明光Ｌ１を導くことができる。 Further, when viewed from the normal ND direction of the digital micromirror device DP, the normal N12 of the illumination light reflecting surface 12 of the TIR prism P1 is inclined with respect to the longitudinal direction of the digital micromirror device DP. Thereby, the illumination light L1 can be efficiently guided to the digital micromirror device DP.
　また、ＴＩＲプリズムＰ１の照明光反射面１２のＯＮ光Ｌ２の光軸ＡＸ２上の法線と該ＴＩＲプリズムＰ１に対応するＯＮ状態のマイクロミラーＭＲのＯＮ光Ｌ２の光軸ＡＸ２上の法線とは同一平面上にある。これにより、デジタル・マイクロミラー・デバイスＤＰで反射したＯＮ光Ｌ２の像高をより小さくすることができる。 The normal line on the optical axis AX2 of the ON light L2 of the illumination light reflecting surface 12 of the TIR prism P1 and the normal line on the optical axis AX2 of the ON light L2 of the micromirror MR in the ON state corresponding to the TIR prism P1 Are on the same plane. Thereby, the image height of the ON light L2 reflected by the digital micromirror device DP can be further reduced.
　また、出射面３２の法線方向にＯＮ光Ｌ２の光軸ＡＸ２が配される投影側プリズムＰ３を色合成プリズムＰ２の出射側に設けている。これにより、色合成プリズムＰ２の小型化を図りながら投影画像の歪みを低減することができる。 Further, a projection-side prism P3 in which the optical axis AX2 of the ON light L2 is arranged in the normal direction of the emission surface 32 is provided on the emission side of the color synthesis prism P2. Thereby, it is possible to reduce the distortion of the projected image while reducing the size of the color combining prism P2.
　また、プロジェクターＰＪは、光学ユニットＰＵのＴＩＲプリズムＰ１１～Ｐ１３に向けてそれぞれ赤色、緑色及び青色の照明光Ｌ１を出射する照明光学系２Ｒ、２Ｂ、２Ｇと、デジタル・マイクロミラー・デバイスＤＰに表示された画像をスクリーンＳＣに拡大投影する投影光学系ＬＮとを備える。これにより、プロジェクターＰＪを小型化できる。 The projector PJ also displays the illumination optical systems 2R, 2B, and 2G that emit red, green, and blue illumination light L1 toward the TIR prisms P11 to P13 of the optical unit PU, and the digital micromirror device DP. A projection optical system LN for enlarging the projected image onto the screen SC. Thereby, the projector PJ can be reduced in size.
　また、ＴＩＲプリズムＰ１の入射面１１の下方から照明光Ｌ１が入射する。これにより、光源１及び照明光学系２を光学ユニットＰＵの下方に集約することができ、投影光学系ＬＮの設計の自由度を高めることができる。 Further, the illumination light L1 enters from below the incident surface 11 of the TIR prism P1. Thereby, the light source 1 and the illumination optical system 2 can be gathered under the optical unit PU, and the design freedom of the projection optical system LN can be increased.
　＜第２実施形態＞
　次に本発明の第２実施形態について説明する。図９は第２実施形態の光学ユニットＰＵを備えるプロジェクターＰＪの概略構成図を示している。図１０～図１２は第２実施形態の光学ユニットＰＵの斜視図、上面図及び側面断面図をそれぞれ示している。説明の便宜上、図１～図８に示す第１実施形態と同様の部分には同一の符号を付している。本実施形態ではＴＩＲプリズムＰ１の構成が第１実施形態とは異なっている。その他の部分は第１実施形態と同様である。 Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 9 shows a schematic configuration diagram of a projector PJ including the optical unit PU of the second embodiment. 10 to 12 are a perspective view, a top view, and a side cross-sectional view, respectively, of the optical unit PU of the second embodiment. For convenience of explanation, the same reference numerals are assigned to the same parts as those in the first embodiment shown in FIGS. In the present embodiment, the configuration of the TIR prism P1 is different from that of the first embodiment. Other parts are the same as those in the first embodiment.
　ＴＩＲプリズムＰ１１の入射面１１はＴＩＲプリズムＰ１２に近づくほどデジタル・マイクロミラー・デバイスＤＰ１に近づくように傾斜している。ＴＩＲプリズムＰ１２の入射面１１はＴＩＲプリズムＰ１３に近づくほどデジタル・マイクロミラー・デバイスＤＰ２に近づくように傾斜している。ＴＩＲプリズムＰ１３の入射面１１はＴＩＲプリズムＰ１２に近づくほどデジタル・マイクロミラー・デバイスＤＰ３から離れるように傾斜している。光吸収部材ＰＴはＴＩＲプリズムＰ１１～Ｐ１３の出射面１５の上方に離れて配される。 The incident surface 11 of the TIR prism P11 is inclined so as to approach the digital micromirror device DP1 as it approaches the TIR prism P12. The incident surface 11 of the TIR prism P12 is inclined so as to approach the digital micromirror device DP2 as it approaches the TIR prism P13. The incident surface 11 of the TIR prism P13 is tilted away from the digital micromirror device DP3 as it approaches the TIR prism P12. The light absorbing member PT is disposed apart above the emission surface 15 of the TIR prisms P11 to P13.
　また、ＴＩＲプリズムＰ１の照明光反射面１２のＯＮ光Ｌ２の光軸ＡＸ２上の法線と該ＴＩＲプリズムＰ１に対応するＯＮ状態のマイクロミラーＭＲのＯＮ光Ｌ２の光軸ＡＸ２上の法線とは同一平面上にない。 The normal line on the optical axis AX2 of the ON light L2 of the illumination light reflecting surface 12 of the TIR prism P1 and the normal line on the optical axis AX2 of the ON light L2 of the micromirror MR in the ON state corresponding to the TIR prism P1 Are not coplanar.
　例えばデジタル・マイクロミラー・デバイスＤＰ２において、マイクロミラーＭＲの入射光の光軸ＡＸ１のＸＹ平面との成す角度が－１７．５°になるとともにＹＺ平面との成す角度が１６．７°になるように入射面１１から照明光Ｌ１を入射させる。この時、照明光Ｌ１の光軸ＡＸ１と入射面１１とは垂直になっている。 For example, in the digital micromirror device DP2, the angle between the optical axis AX1 of the incident light of the micromirror MR and the XY plane is -17.5 ° and the angle between the YZ plane is 16.7 °. The illumination light L1 is made incident from the incident surface 11. At this time, the optical axis AX1 of the illumination light L1 and the incident surface 11 are perpendicular to each other.
　本実施形態でも第１実施形態と同様の効果を得ることができる。また、照明光反射面１２の光軸ＡＸ２上の法線とＯＮ状態のマイクロミラーＭＲの光軸ＡＸ２上の法線とが同一平面上にない。これにより、第１実施形態よりもデジタル・マイクロミラー・デバイスＤＰの短手方向に対する入射面１１の傾きを小さくできるため、光源１及び照明光学系２を光学ユニットＰＵの下方により集約することができる。したがって、投影光学系ＬＮの設計の自由度をより高めることができる。 In this embodiment, the same effect as in the first embodiment can be obtained. Further, the normal line on the optical axis AX2 of the illumination light reflecting surface 12 and the normal line on the optical axis AX2 of the micromirror MR in the ON state are not on the same plane. Thereby, since the inclination of the incident surface 11 with respect to the short direction of the digital micromirror device DP can be made smaller than in the first embodiment, the light source 1 and the illumination optical system 2 can be gathered below the optical unit PU. . Therefore, the degree of freedom in designing the projection optical system LN can be further increased.
　＜第３実施形態＞
　次に本発明の第３実施形態について説明する。図１３及び図１４は第３実施形態の光学ユニットＰＵの上面図及び側面断面図を示している。図１５は第３実施形態の光学ユニットＰＵのデジタル・マイクロミラー・デバイスＤＰ２の正面図を示している。説明の便宜上、図１～図８に示す第１実施形態と同様の部分には同一の符号を付している。本実施形態ではマイクロミラーＭＲの回動軸ＲＡがデジタル・マイクロミラー・デバイスＤＰの短手方向に平行である（長手方向に垂直である）点で第１実施形態とは異なっている。また、ＴＩＲプリズムＰ１の構成も第１実施形態とは異なっている。その他の部分は第１実施形態と同様である。 <Third Embodiment>
Next, a third embodiment of the present invention will be described. 13 and 14 show a top view and a side sectional view of the optical unit PU of the third embodiment. FIG. 15 shows a front view of the digital micromirror device DP2 of the optical unit PU of the third embodiment. For convenience of explanation, the same reference numerals are assigned to the same parts as those in the first embodiment shown in FIGS. This embodiment is different from the first embodiment in that the rotation axis RA of the micromirror MR is parallel to the short direction of the digital micromirror device DP (perpendicular to the longitudinal direction). The configuration of the TIR prism P1 is also different from that of the first embodiment. Other parts are the same as those in the first embodiment.
　ＴＩＲプリズムＰ１１～Ｐ１３の入射面１１は色合成プリズムＰ２からそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３に向かうほどそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３に近づくように傾斜している。また、ＴＩＲプリズムＰ１１～Ｐ１３の入射面１１はそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３の短手方向に対して傾斜していない。ＴＩＲプリズムＰ１の照明光反射面１２のＯＮ光Ｌ２の光軸ＡＸ２上の法線と該ＴＩＲプリズムＰ１に対応するＯＮ状態のマイクロミラーＭＲのＯＮ光Ｌ２の光軸ＡＸ２上の法線とは同一平面上にある。 The incident surfaces 11 of the TIR prisms P11 to P13 are inclined so as to approach the digital micromirror devices DP1 to DP3, respectively, as they go from the color synthesis prism P2 to the digital micromirror devices DP1 to DP3, respectively. Further, the incident surfaces 11 of the TIR prisms P11 to P13 are not inclined with respect to the short direction of the digital micromirror devices DP1 to DP3, respectively. The normal line on the optical axis AX2 of the ON light L2 of the illumination light reflecting surface 12 of the TIR prism P1 and the normal line on the optical axis AX2 of the ON light L2 of the micromirror MR in the ON state corresponding to the TIR prism P1 are the same. It is on a plane.
　入射面１１を介してＴＩＲプリズムＰ１に入射した照明光Ｌ１は照明光反射面１２で全反射した後に該ＴＩＲプリズムＰ１に対応するデジタル・マイクロミラー・デバイスＤＰに向かう。この時、照明光反射面１２で全反射した照明光Ｌ１の光軸ＡＸ１（マイクロミラーＭＲの入射光の光軸）は回動軸ＲＡに対して略直交している。そして、ＯＮ状態のマイクロミラーＭＲで反射したＯＮ光Ｌ２は光軸ＡＸ２がデジタル・マイクロミラー・デバイスＤＰの法線方向に一致するようにＴＩＲプリズムＰ１から出射される。 The illumination light L1 incident on the TIR prism P1 via the incident surface 11 is totally reflected by the illumination light reflecting surface 12, and then travels to the digital micromirror device DP corresponding to the TIR prism P1. At this time, the optical axis AX1 of the illumination light L1 totally reflected by the illumination light reflecting surface 12 (the optical axis of the incident light of the micromirror MR) is substantially orthogonal to the rotation axis RA. The ON light L2 reflected by the micromirror MR in the ON state is emitted from the TIR prism P1 so that the optical axis AX2 coincides with the normal direction of the digital micromirror device DP.
　本実施形態でも第１実施形態と同様の効果を得ることができる。また、第１実施形態及び第２実施形態よりもデジタル・マイクロミラー・デバイスＤＰの短手方向に対する入射面１１の傾きを小さくできるため、光源１及び照明光学系２を光学ユニットＰＵの下方により集約することができる。したがって、投影光学系ＬＮの設計の自由度をより高めることができる。 In this embodiment, the same effect as in the first embodiment can be obtained. In addition, since the inclination of the incident surface 11 with respect to the short direction of the digital micromirror device DP can be made smaller than in the first and second embodiments, the light source 1 and the illumination optical system 2 are gathered below the optical unit PU. can do. Therefore, the degree of freedom in designing the projection optical system LN can be further increased.
　＜第４実施形態＞
　次に本発明の第４実施形態について説明する。図１６及び図１７は第４実施形態の光学ユニットＰＵの斜視図及び上面図を示している。なお、図１６ではカバーガラスＣＧの図示を省略している。説明の便宜上、図１～図８に示す第１実施形態と同様の部分には同一の符号を付している。本実施形態では投影側プリズムＰ３を省いている点で第１実施形態とは異なっている。その他の部分は第１実施形態と同様である。 <Fourth embodiment>
Next, a fourth embodiment of the present invention will be described. 16 and 17 show a perspective view and a top view of the optical unit PU of the fourth embodiment. In FIG. 16, the cover glass CG is not shown. For convenience of explanation, the same reference numerals are assigned to the same parts as those in the first embodiment shown in FIGS. This embodiment is different from the first embodiment in that the projection side prism P3 is omitted. Other parts are the same as those in the first embodiment.
　ＴＩＲプリズムＰ１は第１実施形態と同様のＴＩＲプリズムにより構成される。色合成プリズムＰ２において、ＴＩＲプリズムＰ１２から投影光学系ＬＮに向かってプリズムＰ２２、Ｐ２１、Ｐ２３の順に配置される。また、色合成プリズムＰ２の出射面２３の法線方向にＯＮ光Ｌ２の光軸ＡＸ２が配される。すなわち、出射面２３は光軸ＡＸ２に対して垂直に形成される。出射面２３と投影光学系ＬＮとの間には投影側プリズムＰ３は配されていない。 The TIR prism P1 is composed of the same TIR prism as in the first embodiment. In the color synthesis prism P2, the prisms P22, P21, and P23 are arranged in this order from the TIR prism P12 toward the projection optical system LN. Further, the optical axis AX2 of the ON light L2 is arranged in the normal direction of the emission surface 23 of the color synthesis prism P2. That is, the emission surface 23 is formed perpendicular to the optical axis AX2. The projection-side prism P3 is not disposed between the exit surface 23 and the projection optical system LN.
　上記構成のプロジェクターＰＪにおいて、光源１Ｒ、１Ｇ、１Ｂ（図１参照）からそれぞれ赤色光、緑色光及び青色光が出射されると、それぞれ照明光学系２Ｒ、２Ｇ、２Ｂで集光されてそれぞれ赤色、緑色及び青色の照明光Ｌ１が光学ユニットＰＵに向けて出射される。 In the projector PJ having the above-described configuration, when red light, green light, and blue light are emitted from the light sources 1R, 1G, and 1B (see FIG. 1), respectively, the light is condensed by the illumination optical systems 2R, 2G, and 2B, respectively. The green and blue illumination light L1 is emitted toward the optical unit PU.
　赤色、緑色及び青色の照明光Ｌ１はそれぞれＴＩＲプリズムＰ１１～Ｐ１３の入射面１１に入射した後に照明光反射面１２で全反射する。照明光反射面１２で全反射した赤色、緑色及び青色の照明光Ｌ１は出射面１３から出射した後に、カバーガラスＣＧを透過してそれぞれデジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３に入射する。デジタル・マイクロミラー・デバイスＤＰ１～ＤＰ３のＯＮ状態のマイクロミラーＭＲでそれぞれ反射した赤色、緑色及び青色のＯＮ光Ｌ２は照明光反射面１２を透過した後にそれぞれ入射面２１を介して色合成プリズムＰ２に入射する。 The red, green, and blue illumination light L1 is incident on the incident surface 11 of each of the TIR prisms P11 to P13 and then totally reflected by the illumination light reflecting surface 12. The red, green, and blue illumination lights L1 totally reflected by the illumination light reflecting surface 12 are emitted from the emission surface 13, and then pass through the cover glass CG and enter the digital micromirror devices DP1 to DP3, respectively. The red, green, and blue ON lights L2 reflected by the micromirrors MR in the ON state of the digital micromirror devices DP1 to DP3 are transmitted through the illumination light reflecting surface 12 and then each color combining prism P2 via the incident surface 21. Is incident on.
　赤色のＯＮ光Ｌ２はプリズムＰ２１の全反射面２２で全反射した後に第１ダイクロイックコート面ＤＲで反射し、第２ダイクロイックコート面ＤＢを透過して出射面２３に向かう。緑色のＯＮ光Ｌ２はプリズムＰ２２を透過した後に第１ダイクロイックコート面ＤＲ及び第２ダイクロイックコート面ＤＢの順に透過して出射面２３に向かう。青色のＯＮ光Ｌ２はプリズムＰ２３の全反射面２２で全反射した後に第２ダイクロイックコート面ＤＢで反射し、出射面２３に向かう。この時、各色のＯＮ光Ｌ２は色合成プリズムＰ２を透過する間に色合成され、色合成されたＯＮ光Ｌ２が出射面２３から投影光学系ＬＮに向けて出射される。 The red ON light L2 is totally reflected by the total reflection surface 22 of the prism P21, then reflected by the first dichroic coating surface DR, passes through the second dichroic coating surface DB, and travels toward the emission surface 23. The green ON light L <b> 2 passes through the prism P <b> 22 and then passes through the first dichroic coat surface DR and the second dichroic coat surface DB in this order and travels toward the exit surface 23. The blue ON light L <b> 2 is totally reflected by the total reflection surface 22 of the prism P <b> 23, then reflected by the second dichroic coating surface DB, and travels toward the emission surface 23. At this time, the ON light L2 of each color is color-synthesized while passing through the color synthesis prism P2, and the color-synthesized ON light L2 is emitted from the emission surface 23 toward the projection optical system LN.
　投影光学系ＬＮに入射したＯＮ光Ｌ２はスクリーンＳＣ（図１参照）に投射される。これにより、デジタル・マイクロミラー・デバイスＤＰに表示されたカラー画像はスクリーンＳＣに拡大投影される。この時、アクチュエーター４によりズーミングやフォーカシングが行われる。また、色合成プリズムＰ２の出射面２３はＯＮ光Ｌ２の光軸ＡＸ２が出射面２３の法線方向に一致するようにＯＮ光Ｌ２を出射する。これにより、投影側プリズムＰ３を省きながらスクリーンＳＣに拡大投影される画像の歪みを低減することができる。 The ON light L2 incident on the projection optical system LN is projected on the screen SC (see FIG. 1). As a result, the color image displayed on the digital micromirror device DP is enlarged and projected on the screen SC. At this time, zooming and focusing are performed by the actuator 4. Further, the exit surface 23 of the color combining prism P2 emits the ON light L2 so that the optical axis AX2 of the ON light L2 coincides with the normal direction of the exit surface 23. Thereby, it is possible to reduce distortion of the image enlarged and projected on the screen SC while omitting the projection side prism P3.
　本実施形態でも第１実施形態と同様の効果を得ることができる。また、色合成プリズムＰ２の出射面２３の法線方向にＯＮ光Ｌ２の光軸ＡＸ２が配される。これにより、投影側プリズムＰ３を省くことができるため、光学ユニットＰＵの部品点数を削減することができる。 In this embodiment, the same effect as in the first embodiment can be obtained. Further, the optical axis AX2 of the ON light L2 is arranged in the normal direction of the emission surface 23 of the color synthesis prism P2. Thereby, since the projection side prism P3 can be omitted, the number of parts of the optical unit PU can be reduced.
　なお、本実施形態において、プリズムＰ２１とプリズムＰ２３とを入れ替えて配置してもよい。すなわち、プリズムＰ２１をプリズムＰ２３よりも投影側に配置してもよい。この場合には、プリズムＰ２１の投影側の出射面（色合成プリズムＰ２の出射面２３）の法線方向にＯＮ光Ｌ２の光軸ＡＸ２が配されるように構成する。 In the present embodiment, the prism P21 and the prism P23 may be interchanged. That is, the prism P21 may be arranged on the projection side with respect to the prism P23. In this case, the optical axis AX2 of the ON light L2 is arranged in the normal direction of the emission surface on the projection side of the prism P21 (the emission surface 23 of the color synthesis prism P2).
　また、本実施形態では第１実施形態と同様のＴＩＲプリズムＰ１を用いているが、これに替えて第２実施形態と同様なＴＩＲプリズムＰ１を用いてもよい。 In this embodiment, the same TIR prism P1 as that of the first embodiment is used. However, the same TIR prism P1 as that of the second embodiment may be used instead.
　なお、第１実施形態～第４実施形態において、ＬＥＤに替えて、光源１Ｒ、１Ｇ、１Ｂがそれぞれ赤色レーザーダイオード、緑色レーザーダイオード及び青色レーザーダイオードを有してもよい。 In the first to fourth embodiments, the light sources 1R, 1G, and 1B may include a red laser diode, a green laser diode, and a blue laser diode, respectively, instead of the LED.
　また、第１実施形態～第４実施形態において、光源１Ｒ、１Ｇ、１Ｂに替えて、白色光を出射する光源を備え、白色光をダイクロイックフィルタ等を用いて赤色光、緑色光及び青色光に色分解した後にそれぞれＴＩＲプリズムＰ１１～Ｐ１３の入射面１１に入射させてもよい。 In the first to fourth embodiments, a light source that emits white light is provided instead of the light sources 1R, 1G, and 1B, and the white light is converted into red light, green light, and blue light using a dichroic filter or the like. After the color separation, the light may be incident on the incident surface 11 of each of the TIR prisms P11 to P13.
　本発明は、デジタル・マイクロミラー・デバイスを有する光学ユニット及びそれを備えたプロジェクターに利用することができる。 The present invention can be used for an optical unit having a digital micromirror device and a projector including the optical unit.
　ＰＪ　　プロジェクター
　ＬＮ　　投影光学系
　ＰＵ　　光学ユニット
　ＰＴ　　光吸収部材
　ＤＰ１～ＤＰ３　　デジタル・マイクロミラー・デバイス
　ＤＳ　　画像表示面
　ＭＲ　　マイクロミラー
　ＭＳ　　画素反射面
　ＣＧ　　カバーガラス
　Ｐ１１～Ｐ１３　　ＴＩＲプリズム
　Ｐ２　　色合成プリズム
　Ｐ３　　投影側プリズム
　Ｌ１　　照明光
　Ｌ２　　ＯＮ光（投影光）
　Ｌ３　　ＯＦＦ光（不要光）
　ＡＸ１　　照明光の光軸
　ＡＸ２　　投影光（ＯＮ光）の光軸
　ＡＸ３　　ＯＦＦ光の光軸
　ＭＳ２　　ＯＮ反射面
　ＭＳ３　　ＯＦＦ反射面
　１Ｒ、１Ｇ、１Ｂ　　　光源
　２Ｒ、２Ｇ、２Ｂ　　　照明光学系
　３　　　　制御部
　４　　　　アクチュエーター
　１２　　　照明光反射面
　５１、５２　　　レンズ
　ＡＸ　　　光軸
　ＳＣ　　　スクリーン
　ＤＲ　　　第１ダイクロイックコート面
　ＤＢ　　　第２ダイクロイックコート面 PJ Projector LN Projection optical system PU Optical unit PT Light absorbing member DP1 to DP3 Digital micromirror device DS Image display surface MR Micromirror MS Pixel reflection surface CG Cover glass P11 to P13 TIR prism P2 Color synthesis prism P3 Projection side prism L1 Illumination light L2 ON light (projection light)
L3 OFF light (unnecessary light)
AX1 Optical axis of illumination light AX2 Optical axis of projection light (ON light) AX3 Optical axis of OFF light MS2 ON reflection surface MS3 OFF reflection surface 1R, 1G, 1B Light source 2R, 2G, 2B Illumination optical system 3 Control unit 4 Actuator 12 Illumination light reflecting surface 51, 52 Lens AX Optical axis SC screen DR First dichroic coated surface DB Second dichroic coated surface

Claims (10)

  1. 　回動軸を中心に回動する複数のマイクロミラーの各面の傾きがＯＮ／ＯＦＦ制御されて照明光を強度変調することにより画像を形成する平面視略矩形の複数のデジタル・マイクロミラー・デバイスと、
    　各前記デジタル・マイクロミラー・デバイスに対応してそれぞれ設けられるとともに互いに波長の異なる照明光を各前記デジタル・マイクロミラー・デバイスに導く複数のＴＩＲプリズムと、
    　各前記デジタル・マイクロミラー・デバイスのＯＮ状態の各前記マイクロミラーで反射されたＯＮ光を色合成して投影側に射出する色合成プリズムと、
    　を備えた光学ユニットであって、
    　前記デジタル・マイクロミラー・デバイスと前記色合成プリズムとの間に前記ＴＩＲプリズムを配置し、
    　前記色合成プリズムは、所定波長のＯＮ光を反射して該所定波長以外のＯＮ光を透過する第１ダイクロイックコート面及び第２ダイクロイックコート面を有し、
    　各前記デジタル・マイクロミラー・デバイスを法線方向から見て、第１ダイクロイックコート面と第２ダイクロイックコート面との交線と、該デジタル・マイクロミラー・デバイスの長手方向との成す角度が４５°よりも小さいことを特徴とする光学ユニット。     A plurality of digital micromirror devices having a substantially rectangular shape in plan view that form an image by intensity-modulating illumination light by controlling the inclination of each surface of a plurality of micromirrors that rotate about a rotation axis to be ON / OFF-controlled. When,
    A plurality of TIR prisms provided corresponding to each of the digital micromirror devices and guiding illumination light having different wavelengths to each of the digital micromirror devices;
    A color synthesizing prism that color-synthesizes the ON light reflected by each of the micromirrors in the ON state of each of the digital micromirror devices and emits the light to the projection side;
    An optical unit comprising:
    Placing the TIR prism between the digital micromirror device and the color combining prism;
    The color synthesis prism has a first dichroic coating surface and a second dichroic coating surface that reflect ON light having a predetermined wavelength and transmit ON light having a wavelength other than the predetermined wavelength.
    When each of the digital micromirror devices is viewed from the normal direction, an angle formed by an intersection line between the first dichroic coated surface and the second dichroic coated surface and a longitudinal direction of the digital micromirror device is 45 °. An optical unit characterized by being smaller than.
  2. 　前記法線方向から見て、前記交線が前記長手方向に略一致することを特徴とする請求項１に記載の光学ユニット。 The optical unit according to claim 1, wherein the intersecting line substantially coincides with the longitudinal direction when viewed from the normal direction.
  3. 　前記回動軸が前記長手方向に対して４５°傾斜していることを特徴とする請求項１または請求項２に記載の光学ユニット。 3. The optical unit according to claim 1, wherein the rotation shaft is inclined by 45 ° with respect to the longitudinal direction.
  4. 　前記回動軸が前記マイクロミラーの入射光の光軸方向に対して直交しないことを特徴とする請求項３に記載の光学ユニット。 The optical unit according to claim 3, wherein the rotation axis is not orthogonal to the optical axis direction of the incident light of the micromirror.
  5. 　前記法線方向から見て、前記ＴＩＲプリズムの照明光反射面の法線が前記長手方向に対して傾斜していることを特徴とする請求項３または請求項４に記載の光学ユニット。 The optical unit according to claim 3 or 4, wherein a normal line of the illumination light reflecting surface of the TIR prism is inclined with respect to the longitudinal direction when viewed from the normal direction.
  6. 　前記ＴＩＲプリズムの照明光反射面のＯＮ光の光軸上の法線とＯＮ状態の前記マイクロミラーのＯＮ光の光軸上の法線とが同一平面上にあることを特徴とする請求項１～請求項５のいずれかに記載の光学ユニット。 The normal line on the optical axis of the ON light of the illumination light reflecting surface of the TIR prism and the normal line on the optical axis of the ON light of the micromirror in the ON state are on the same plane. The optical unit according to claim 5.
  7. 　前記ＴＩＲプリズムから出射される照明光が前記マイクロミラーに導かれ、前記マイクロミラーで反射したＯＮ光は前記ＴＩＲプリズム及び前記色合成プリズムの順に透過することを特徴とする請求項１～請求項６のいずれかに記載の光学ユニット。 The illumination light emitted from the TIR prism is guided to the micromirror, and the ON light reflected by the micromirror is transmitted in the order of the TIR prism and the color synthesizing prism. The optical unit according to any one of the above.
  8. 　出射面の法線方向にＯＮ光の光軸が配される投影側プリズムを前記色合成プリズムの出射側に設けたことを特徴とする請求項１～請求項７のいずれかに記載の光学ユニット。 8. The optical unit according to claim 1, wherein a projection-side prism on which an optical axis of ON light is arranged in the normal direction of the emission surface is provided on the emission side of the color synthesis prism. .
  9. 　請求項１～請求項８のいずれかの光学ユニットと、光源と、前記光学ユニットの各前記ＴＩＲプリズムに向けてそれぞれ波長の異なる照明光を出射する照明光学系と、前記デジタル・マイクロミラー・デバイスに表示された画像をスクリーンに拡大投影する投影光学系とを備えたことを特徴とするプロジェクター。 9. The optical unit according to claim 1, a light source, an illumination optical system that emits illumination light having different wavelengths toward each TIR prism of the optical unit, and the digital micromirror device A projection optical system that enlarges and projects the image displayed on the screen onto a screen.
  10. 　前記ＴＩＲプリズムの入射面の下方から照明光が入射することを特徴とする請求項９に記載のプロジェクター。 The projector according to claim 9, wherein illumination light is incident from below the incident surface of the TIR prism.
PCT/JP2017/002226 2016-01-28 2017-01-24 Optical unit, and projector provided therewith WO2017130924A1 (en)

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