JP2018132548A - Illumination device and projector - Google Patents

Abstract

An illumination device capable of improving a light collecting state is provided. Moreover, a projector provided with the said illuminating device is provided. A light source device that emits light including first to fourth light beam arrays in a first polarization state, a collimating optical system, a light beam compression optical system including a polarization conversion unit and an optical path changing unit, An illumination device including a light intensity uniformizing optical system, a condensing lens, and a diffused light generating element. In the optical path changing unit, the first reflecting element, the first and second polarization separation elements, and the second reflecting element are arranged in this order. The polarization conversion unit includes first and second phase difference elements. The first light beam train is reflected by the first reflecting element toward the first polarization separation device, the second light beam train is transmitted through the first phase difference device, and the third light beam train is the first light beam train. 2 is transmitted through the two phase difference elements, and the fourth light beam train is reflected by the second reflection element toward the second polarization separation element. The first polarization separation element combines the first and second light beam trains, and the second polarization separation element combines the fourth and third light beam trains. [Selection] Figure 3

Description

  The present invention relates to a lighting device and a projector.

  2. Description of the Related Art In recent years, semiconductor lasers that can obtain light with high brightness and high output have attracted attention as light sources for light source devices used in projectors. As the number of semiconductor lasers increases with the increase in the brightness of the light source, the beam width increases and the aperture of the condenser lens increases.

  Therefore, for example, in Patent Document 1 below, an afocal pattern is configured that includes an array light source in which a plurality of semiconductor lasers are two-dimensionally arranged, a convex lens, and a concave lens, and adjusts the width of a light beam emitted from the array light source. An illumination device for a projector including an optical system is disclosed. The reduced light beam whose beam width has been reduced by the afocal optical system is condensed by the condensing optical system, and enters the phosphor layer (diffused light generating element).

JP 2014-138148 A

  By the way, in the above prior art, the reduced light beam is incident on almost the entire region of the lens constituting the condensing optical system, and therefore a part of the reduced light beam is also incident on the lens peripheral part which is greatly affected by the aberration. As a result, there is a concern that the light collection state of the light (reduced beam bundle) on the phosphor layer may be lowered.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the illuminating device which can improve a condensing state. Another object is to provide a projector including the lighting device.

  According to the first aspect of the present invention, a light source device that emits a light bundle including the first to fourth light beam arrays in the first polarization state, a collimating optical system on which the light bundle enters, and the collimating optics A light bundle compression optical system provided downstream of the system, a light intensity uniformizing optical system provided downstream of the light bundle compression optical system, and a condenser lens provided downstream of the light intensity uniformization optical system And a diffused light generating element provided at a subsequent stage of the condenser lens, the light bundle compression optical system includes a polarization conversion unit and an optical path changing unit, and the optical path changing unit is a first reflection An element, a first polarization separation element, a second polarization separation element, and a second reflection element are arranged in this order, and the polarization conversion unit is provided in the upper stage of the first polarization separation element. 1 phase difference element and a second position provided in the upper stage of the second polarization separation element And the first to fourth light beam rows are arranged in this order in the upper stage of the beam bundle compression optical system, and the first light beam row is the first reflecting element. Reflected toward the first polarization separation element, the second light beam train passes through the first retardation element, and the third light beam train passes through the second retardation element. The fourth light beam train is reflected by the second reflecting element toward the second polarization separation element, and the first polarization separation element passes the first light beam train on the second light. An illuminating device is provided that combines with the third light beam array, wherein the second polarization separation element combines with the third light beam array.

  In the illuminating device according to the first aspect, the light intensity inside the light beam after reducing the beam width is reduced by shifting the optical paths of the first light beam row and the fourth light beam row to the inside of the light beam. Relatively strong. Therefore, the light condensing state on the diffused light generating element is improved by causing a large amount of light in the light bundle to be incident on the inner side of the condensing lens which is less susceptible to the aberration than the peripheral portion. Therefore, bright diffused light can be generated.

  In the first aspect, it is preferable that the first light beam row and the fourth light beam row are arranged at the center of the light beam in the lower stage of the light beam compression optical system.

  According to this configuration, the light intensity at the center of the light beam can be relatively increased in the lower stage of the light beam compression optical system. Accordingly, a large amount of light in the light bundle is incident on the central portion of the condensing lens that is not easily affected by aberrations, so that the condensing state on the diffused light generating element can be further improved.

  In the first aspect, a cross section of each of the plurality of light beams constituting the first light beam array has a major axis direction in a direction in which the plurality of light beams are arranged. The reflecting element preferably has a longitudinal direction in the direction in which the plurality of light beams are arranged.

  According to this configuration, the width of the first reflecting element in the short direction is reduced. Therefore, the apparatus configuration can be reduced in size.

  In the first aspect, the light beam bundle further includes a fifth light beam array made of linearly polarized light, and a third retardation element provided in an optical path between the optical path changing unit and the condenser lens And a third polarization separation element provided in an optical path between the third phase difference element and the condenser lens.

  According to this configuration, for example, by appropriately setting the direction of the optical axis of the third phase difference element, the light of the fifth light beam train that has passed through the third phase difference element is changed to the third phase difference element. The light can be converted into light including the S-polarized component and the P-polarized component with respect to the polarization separation element at a predetermined ratio. Thereby, the ratio of the light incident on the diffused light generating element can be adjusted.

  According to the second aspect of the present invention, the illumination device according to the first aspect, a light modulation device that generates illumination light by modulating illumination light from the illumination device according to image information, and the projection of the image light. A projection optical system is provided.

  According to the projector according to the second aspect, since bright illumination light is obtained, an image can be displayed brightly.

Schematic which shows the optical system of a projector. The figure which shows schematic structure of an illuminating device. The principal part enlarged view which shows the periphery structure of a light source device. The figure which shows the light beam bundle before reduction by a light beam width compression means. The figure which shows the light beam after reduction | decrease by a light beam width compression means.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

First, an example of a projector according to the present embodiment will be described.
FIG. 1 is a diagram illustrating a schematic configuration of a projector according to the present embodiment.
As shown in FIG. 1, the projector 1 of this embodiment is a projection type image display device that displays a color video on a screen SCR. The projector 1 includes an illumination device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a combining optical system 5, and a projection optical system 6.

  The color separation optical system 3 separates the illumination light WL from the illumination device 2 into a red light LR, a green light LG, and a blue light LB. The color separation optical system 3 includes a first dichroic mirror 7a and a second dichroic mirror 7b, a first total reflection mirror 8a, a second total reflection mirror 8b, a third total reflection mirror 8c, and a first A relay lens 9a and a second relay lens 9b are roughly provided.

  The first dichroic mirror 7a separates the illumination light WL into red light LR and other light (green light LG and blue light LB). The first dichroic mirror 7a transmits the separated red light LR and reflects other light (green light LG and blue light LB). On the other hand, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB, thereby separating the other light into the green light LG and the blue light LB.

  The first total reflection mirror 8a is disposed in the optical path of the red light LR, and reflects the red light LR transmitted through the first dichroic mirror 7a toward the light modulation device 4R. On the other hand, the second total reflection mirror 8b and the third total reflection mirror 8c are arranged in the optical path of the blue light LB, and guide the blue light LB transmitted through the second dichroic mirror 7b to the light modulation device 4B. The green light LG is reflected from the second dichroic mirror 7b toward the light modulation device 4G.

  The first relay lens 9a and the second relay lens 9b are arranged on the light emission side of the second total reflection mirror 8b in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b function to compensate for the optical loss of the blue light LB caused by the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG. have.

  The light modulation device 4R modulates the red light LR according to the image information, and forms image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to the image information, and forms image light corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to the image information, and forms image light corresponding to the blue light LB.

  For example, a transmissive liquid crystal panel is used for the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. A polarizing plate (not shown) is disposed on each of the incident side and the emission side of the liquid crystal panel.

  Further, a field lens 10R, a field lens 10G, and a field lens 10B are disposed on the incident side of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively. The field lens 10R, the field lens 10G, and the field lens 10B collimate the red light LR, the green light LG, and the blue light LB incident on the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively.

  Image light from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B is incident on the combining optical system 5. The synthesis optical system 5 synthesizes image lights corresponding to the red light LR, green light LG, and blue light LB, respectively, and emits the synthesized image light toward the projection optical system 6. For example, a cross dichroic prism is used for the combining optical system 5.

  The projection optical system 6 includes a projection lens group, and enlarges and projects the image light combined by the combining optical system 5 toward the screen SCR. As a result, an enlarged color image is displayed on the screen SCR.

(Lighting device)
Then, the illuminating device 2 which concerns on one Embodiment of this invention is demonstrated.
FIG. 2 is a diagram showing a schematic configuration of the illumination device 2. As shown in FIG. 2, the illumination device 2 includes a light source device 71, a collimating optical system 72, a light beam width compressing unit 73, a homogenizer optical system 25, a phase difference plate 26 a, a polarization beam splitter 27, A pickup optical system 28, a phosphor wheel 29 having a phosphor layer, a phase difference plate 26b, a second pickup optical system 41, a rotary diffusing element 42, and a uniform illumination optical system 40. . In the present embodiment, the polarization beam splitter 27 corresponds to a “third polarization separation element” recited in the claims. In the following description, the polarization beam splitter is abbreviated as PBS.

  Hereinafter, in the description using the drawings, description will be made using the XYZ coordinate system. 2 and 3, the X direction defines the arrangement direction of the light beam arrays constituting the light bundle emitted from the light source device 71, the Y direction defines the light emission direction from the light source device 71, and the Z direction is The directions are orthogonal to the X direction and the Y direction, respectively, and define the vertical direction.

  The uniform illumination optical system 40 includes an integrator optical system 31, a polarization conversion element 32, and a superimposing optical system 33. The polarization conversion element 32 is not essential. The uniform illumination optical system 40 uniformizes the intensity distribution of the illumination light WL in the illuminated area.

  The integrator optical system 31 includes a first multi-lens array 31a and a second multi-lens array 31b. The polarization conversion element 32 includes, for example, a polarization separation film and a phase difference plate, and converts the illumination light WL into linearly polarized light. The superimposing optical system 33 is composed of, for example, a superimposing lens, and superimposes the illumination light WL emitted from the polarization conversion element 32 on the illuminated area. In the present embodiment, the integrator optical system 31 and the superimposing optical system 33 make uniform in the pixel formation regions of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B that are the illumination regions.

  The light source device 71, the collimating optical system 72, the light beam width compressing means 73, the homogenizer optical system 25, the phase difference plate 26a, the PBS 27, the phase difference plate 26b, and the second pickup optical system 41 It is arranged on the axis AX0. The PBS 27 and the first pickup optical system 28 are disposed on the optical axis AX1 orthogonal to the optical axis AX0.

  The light source device 71 includes a plurality of semiconductor lasers 20. The semiconductor laser 20 emits, for example, a blue light beam BL. In the present embodiment, the light source device 71 includes, for example, the semiconductor lasers 20 arranged in 6 rows and 4 columns (see FIG. 4 described later). The number and arrangement of the semiconductor lasers 20 are not particularly limited. The light beam BL emitted from the semiconductor laser 20 is linearly polarized light. In the present embodiment, the semiconductor laser 20 emits S-polarized component light with respect to the PBS 27 as a light beam BL. S-polarized light corresponds to the “first polarization state” recited in the claims.

FIG. 3 is an enlarged view showing the configuration of the light source device 71, which is a main part of the illumination device 2, and its surroundings, and is a plan view of the light source device 71 viewed from the + Z direction.
In FIG. 3, the four light beams BL arranged in the Z-axis direction are referred to as a light beam array, and the six light beam arrays arranged in the direction from the −X direction to the + X direction are sequentially arranged as the light beam arrays BR1, BR5, BR2, BR3. They are referred to as BR6 and BR4. The light beams constituting each of the light beam trains BR1, BR5, BR2, BR3, BR6, BR4 are referred to as light beams BL1, BL5, BL2, BL3, BL6, BL4, respectively.

  In the present embodiment, the light source device 71 emits a light beam K1 including the respective light beam trains BR1, BR2, BR3, BR4, BR5, BR6 toward the collimating optical system 72. The light beam trains BR1, BR2, BR3, BR4, and BR5 correspond to “first to fifth light beam trains” in the claims, respectively.

  As shown in FIG. 3, each light beam BL emitted from the light source device 71 passes through the collimating optical system 72, is converted into a parallel light beam, and enters the light beam width compression unit 73. The collimating optical system 72 includes, for example, a plurality of collimating lenses 72 a arranged in an array corresponding to the arrangement of the plurality of semiconductor lasers 20.

  In the present embodiment, the beam width compressing unit 73 is provided in the subsequent stage of the collimating optical system 72, and reduces the light beam K1 emitted from the collimating optical system 72 and traveling in the + Y direction in the X direction intersecting the + Y direction. The light is emitted as a reduced beam bundle K1s. The reduced light beam K1s emitted from the beam width compression unit 73 is incident on the homogenizer optical system 25. In the present embodiment, the beam width compression means 73 corresponds to a “light bundle compression optical system” recited in the claims.

  In the present embodiment, the light beam width compression unit 73 includes a polarization conversion unit 74 and an optical path changing unit 75. The optical path changing unit 75 includes a first reflection element 75a, a first polarization separation element 75b, a second polarization separation element 75c, and a second reflection element 75d, which are sequentially arranged along the + X direction. I have.

  In the present embodiment, the beam width compressing unit 73 includes a first prism 61, a second prism 62, and a third prism 63.

  The first prism 61 has a first end surface (−X side end surface) 61a, a second end surface (+ X side end surface) 61b, a light incident surface 61c, and a light exit surface 61d, and a cross section by an XY plane is provided. It has a substantially parallelogram shape. The first reflective element 75a is provided on the first end face 61a. The light incident surface 61c and the light emitting surface 61d are surfaces perpendicular to the optical axis AX0. Therefore, the light beam BL emitted from the light source device 71 is not refracted by the light incident surface 61c and the light emitting surface 61d.

  The second prism 62 has a first end face (end face on the −X side) 62a, a second end face (end face on the + X side) 62b, a light incident face 62c, and a light exit face 62d. It has a substantially parallelogram shape. The second reflecting element 75d is provided on the second end face 62b. The light incident surface 62c and the light emitting surface 62d are surfaces perpendicular to the optical axis AX0. Therefore, the light beam BL emitted from the light source device 71 is not refracted by the light incident surface 62c and the light emitting surface 62d.

  The third prism 63 has a first end surface (−X side end surface) 63a, a second end surface (+ X side end surface) 63b, and a third end surface 63c facing the light source device 71, and is an XY plane. The cross section by is a substantially triangular shape. The third end surface 63c is a surface orthogonal to the optical axis AX0, and the light beam BL from the light source device 71 is incident thereon.

  In the first prism 61, the second prism 62, and the third prism 63, the first end surface 63 a faces the second end surface 61 b of the first prism 61, and the second end surface 63 b is the first end of the second prism 62. It is fixed so as to face the end face 62a. The prisms 61, 62, and 63 are bonded to each other by, for example, an adhesive layer (not shown).

  In the present embodiment, the first polarization separation element 75b is provided between the first end face 63a and the second end face 61b, and the second polarization separation element 75c is the second end face 63b and the first end face 62a. It is provided in between.

  The first reflecting element 75a and the second reflecting element 75d are configured by a reflecting member that reflects the light beam BL, such as a mirror. The first reflecting element 75a is arranged to form an angle of 45 ° with respect to the optical axis AX0. In the present embodiment, the first reflecting element 75a is disposed on the optical path of the light beam train BR1.

  In the present embodiment, the light beam BL emitted from the semiconductor laser 20 has an elliptical cross section (see FIG. 4). Specifically, the cross section of each of the plurality of light beams BL1 constituting the light beam array BR1 has a major axis direction in the arrangement direction (Z direction) of the plurality of light beams BL1.

In the present embodiment, the first reflecting element 75a has a longitudinal direction in the direction (Z direction) in which the plurality of light beams BL1 are arranged.
According to this configuration, for example, the shorter direction of the first reflecting element 75a than the case where the cross section of each of the plurality of light beams BL1 has the minor axis direction in the arrangement direction (Z direction) of the plurality of light beams BL1. The width of can be reduced.

  The second reflecting element 75d is arranged to form an angle of −45 ° with respect to the optical axis AX0. In the present embodiment, the second reflecting element 75d is disposed on the optical path of the light beam train BR4.

  The first polarization separation element 75b and the second polarization separation element 75c are configured by a polarization beam splitter (PBS). The first polarization separation element 75b is arranged in parallel with the first reflection element 75a, that is, at an angle of −45 ° with respect to the optical axis AX0. In the present embodiment, the first polarization separation element 75b is disposed on the optical path of the light beam array BR2.

  The second polarization separation element 75c is arranged in parallel with the second reflection element 75d, that is, at an angle of 45 ° with respect to the optical axis AX0. In the present embodiment, the second polarization separation element 75c is disposed on the optical path of the light beam train BR3.

  The polarization conversion unit 74 includes a first phase difference element 74a and a second phase difference element 74b. The first retardation element 74a is composed of a half-wave plate provided on the upper stage (−Y side) of the first polarization separation element 75b. That is, the first phase difference element 74a is provided on the third end face 63c located on the upper stage of the first polarization separation element 75b in the optical path of the light beam row BR2.

The second retardation element 74b is composed of a half-wave plate provided on the upper stage (−Y side) of the second polarization separation element 75c. That is, the second phase difference element 74b is provided on the third end face 63c located on the upper stage of the second polarization separation element 75c in the optical path of the light beam train BR3.
The first phase difference element 74a and the second phase difference element 74b may be composed of a single half-wave plate.

  Based on such a configuration, the light beam BL1 is reflected in the + X direction by the first reflecting element 75a and is incident on the first polarization separating element 75b. Since the light beam BL1 is S-polarized light, it is reflected in the + Y direction by the first polarization separation element 75b.

  The light beam BL2 passes through the first phase difference element 74a, is converted to P-polarized light, and enters the first polarization separation element 75b. The P-polarized light beam BL2 passes through the first polarization separation element 75b and proceeds in the + Y direction. In this way, the first polarization separation element 75b combines the light beam array BR1 (light beam BL1) composed of S-polarized light and the light beam array BR2 (light beam BL2) composed of P-polarized light. In FIG. 3, in order to make the drawing easy to see, the incident positions of the light beam trains BR1 and BR2 in the first polarization separation element 75b are displayed while being shifted in the X direction.

  The light beam BL3 passes through the second phase difference element 74b, is converted to P-polarized light, and enters the second polarization separation element 75c. The P-polarized light beam BL3 passes through the second polarization separation element 75c and proceeds in the + Y direction.

  The light beam BL4 is reflected in the −X direction by the second reflecting element 75d and is incident on the second polarization separation element 75c. Since the light beam BL4 is S-polarized light, it is reflected toward the + Y direction by the second polarization separation element 75c. In this way, the second polarization separation element 75c combines the light beam array BR3 (light beam BL3) composed of P-polarized light and the light beam array BR4 (light beam BL4) composed of S-polarized light. In FIG. 3, the incident positions of the light beam trains BR3 and BR4 in the second polarization separation element 75c are shifted and displayed in the X direction for easy viewing.

  The light beam BL5 is incident between the first reflection element 75a and the first polarization separation element 75b in the X direction of the first prism 61. Therefore, the light beam BL5 passes through the first prism 61 and is emitted from the light emission surface 61d.

  The light beam BL6 is incident between the second polarization separation element 75c and the second reflection element 75d in the X direction of the second prism 62. Therefore, the light beam BL6 passes through the second prism 62 and is emitted from the light exit surface 62d.

  FIG. 4 is a diagram showing the reduction of the light beam bundle K1 by the light beam width compressing unit 73, FIG. 4A shows the light beam bundle K1 before reduction, and FIG. 4B shows the reduced light beam bundle K1s after reduction.

  The light beam train BR1 emitted from the light source device 71 is shifted in the + X direction by the light beam width compression means 73 as shown in FIG. 4A. Thereby, after the reduction, the light beam train BR1 is positioned between the light beam train BR5 and the light beam train BR3 as shown in FIG. 4B. In the present embodiment, the light beam row BR1 is disposed at a position overlapping the light beam row BR2 when viewed in plan from the Z direction. The light beam array BR1 is disposed at the center of the reduced light bundle K1s in the X direction.

  Further, the light beam array BR4 emitted from the light source device 71 is shifted in the −X direction by the light beam width compressing unit 73 as shown in FIG. 4A. Thereby, after the reduction, the light beam train BR4 is positioned between the light beam train BR2 and the light beam train BR6 as shown in FIG. 4B. In the present embodiment, the light beam array BR4 is disposed at a position overlapping the light beam array BR3 when viewed in plan from the Z direction. The light beam array BR4 is disposed at the center of the reduced light bundle K1s in the X direction.

  As described above, the light beam width compressing unit 73 converts the light beam K1 having the light beam width W1 into the reduced light beam K1s having the light beam width W2, as shown in FIG. The traveling direction of the reduced light beam K1s is substantially the same as when the light beam K1 is incident on the light beam width compression unit 73.

  In the reduced light bundle K1s, the four light beam trains BR1, BL2, BL3, BL4 are located in the center in the X direction. Therefore, in the reduced light beam K1s, the light intensity at the central portion is relatively stronger than the light intensity at other portions.

  The reduced beam bundle K1s whose beam width has been reduced by the beam width compressing unit 73 is incident on the homogenizer optical system 25 provided at the subsequent stage of the beam width compressing unit 73. The homogenizer optical system 25 makes the intensity distribution of the reduced beam bundle K1s emitted from the light beam width compression means 73 uniform in the illuminated area. The homogenizer optical system 25 includes, for example, a first multi-lens array 25a and a second multi-lens array 25b. The first multi-lens array 25a has a plurality of lenses 25am arranged at an equal pitch. The second multi-lens array 25b includes a plurality of lenses 25bm arranged at the same pitch as the lens 25am. In the present embodiment, the homogenizer optical system 25 corresponds to a “light intensity uniformizing optical system” recited in the claims.

  The phase difference plate 26a is, for example, a half-wave plate that can be rotated. Since the reduced beam bundle K1s emitted from the beam width compressing unit 73 is linearly polarized light, the reduced beam bundle K1s is converted into an S-polarized component for the PBS 27 by appropriately setting the direction of the optical axis of the half-wave plate. It can be set as the light which contains P polarization component by a predetermined ratio. In the present embodiment, the phase difference plate 26a corresponds to a “third phase difference element” recited in the claims.

  The PBS 27 is disposed at an angle of 45 ° with respect to the optical axis AX0 and the optical axis AX1. The PBS 27 reflects the S-polarized component of the incident light and transmits the P-polarized component of the incident light. The S-polarized component is reflected by the PBS 27 and travels toward the phosphor wheel 29. The P-polarized light component passes through the PBS 27 and travels toward the rotary diffusing element 42.

  In the present embodiment, as shown in FIG. 4B, the S-polarized light beam array BR1 and the light beam array BR4 and the P-polarized light beam array BR2 and the light beam array BR3 are collected at the center of the reduced beam bundle K1s. Arranged. Further, an S-polarized light beam array BR5 and a light beam array BR6 are disposed in the periphery of the reduced beam bundle K1s. That is, the reduced light bundle K1s is composed of light whose central portion contains S-polarized light and P-polarized light at the same ratio, and its peripheral portion is composed of light containing only S-polarized light.

  Therefore, in the reduced light beam K1s transmitted through the retardation plate 26a, the ratio of the S-polarized component and the P-polarized component in the peripheral portion changes according to the rotation angle of the optical axis of the retardation plate 26a. However, the ratio of the S-polarized component and the P-polarized component at the center does not change.

  Therefore, the light at the center of the reduced light bundle K1s is separated by the PBS 27 into the S-polarized light beam BLs and the P-polarized light beam BLp at the same rate. On the other hand, the light around the reduced light bundle K1s is separated by the PBS 27 into S-polarized light BLs and P-polarized light BLp at a predetermined ratio. Therefore, both the S-polarized light beam BLs and the P-polarized light beam BLp generated by the PBS 27 have a relatively strong light intensity at the center.

  The S-polarized light beam BLs generated by the PBS 27 is incident on the first pickup optical system 28. The first pickup optical system 28 collects the light beam BLs toward the phosphor layer 47 on the phosphor wheel 29. The first pickup optical system 28 includes, for example, a first pickup lens 28a and a second pickup lens 28b. In the present embodiment, the first pickup lens 28a and the second pickup lens 28b correspond to “condensing lenses” described in the claims.

  The light emitted from the first pickup optical system 28 enters the phosphor wheel 29. The phosphor wheel 29 is a reflection-type rotating fluorescent plate, and includes a phosphor layer 47 that emits fluorescent light (diffused light), a rotating plate 49 that supports the phosphor layer 47, and the phosphor layer 47 and the rotating plate 49. A reflective film (not shown) that reflects fluorescent light provided therebetween, and a drive motor 50 that drives the rotating plate 49 are provided. As the rotating plate 49, for example, a disc is used, but the shape of the rotating plate 49 is not limited to a disc, and may be a flat plate.

  The phosphor layer 47 includes phosphor particles that absorb the light beam BLs, convert it into yellow fluorescence YL, and emit it. As the phosphor particles, for example, YAG (yttrium / aluminum / garnet) phosphors can be used. In addition, the material for forming the phosphor particles may be one kind, or a mixture of particles formed using two or more kinds of materials may be used as the phosphor particles. In the present embodiment, the phosphor layer 47 corresponds to a “diffused light generating element” recited in the claims.

  Incidentally, in general, the influence of aberration is large in the peripheral portion of the lens. For this reason, the light incident on the peripheral portion of the lens is deteriorated in the condensing state. In order to efficiently generate fluorescence in the phosphor layer 47, it is important that the first pickup lens 28a and the second pickup lens 28b do not allow light to enter the peripheral portion where the influence of aberration is large.

  According to the illuminating device 2 of the present embodiment, the S-polarized light beam BLs generated from the reduced light beam K1s is incident on the first pickup optical system 28 (first and second pickup lenses 28a and 28b). It has become. Similar to the reduced light bundle K1s, the S-polarized light beam BLs has a relatively strong light intensity at the center. Therefore, in the first and second pickup lenses 28a and 28b, the amount of incident light at the center of the lens where the influence of aberration is small increases, and the amount of incident light at the periphery of the lens where the influence of aberration is large.

  Therefore, since the light beam BLs is hardly affected by the aberration, the light condensing state on the phosphor layer 47 by the first pickup optical system 28 can be improved. Therefore, fluorescence YL can be efficiently generated in the phosphor layer 47.

  Further, the S-polarized light beam BLs can change only the light intensity at the peripheral portion while keeping the light intensity at the central portion constant by adjusting the rotation angle of the optical axis of the phase difference plate 26a. Therefore, it is possible to adjust the brightness of the fluorescence YL while suppressing the influence of the aberration caused by the first pickup optical system 28.

  For example, the first pickup optical system 28 can be reduced in size by removing a portion (peripheral portion) where the reduced beam bundle K1s is not incident on the first and second pickup lenses 28a and 28b, for example, by grinding. it can.

  On the other hand, the P-polarized light beam BLp generated by the PBS 27 enters the phase difference plate 26b. The phase difference plate 26b is a quarter wavelength plate. The light beam BLp is converted to circularly polarized light (for example, clockwise circularly polarized light) BLc1 by passing through the phase difference plate 26b. The light beam BLc1 that has passed through the phase difference plate 26b enters the second pickup optical system 41. The second pickup optical system 41 condenses incident light toward the rotary diffusing element 42. The second pickup optical system 41 includes, for example, a first pickup lens 41a and a second pickup lens 41b. In the present embodiment, the first pickup lens 41a and the second pickup lens 41b correspond to a “condensing lens” described in the claims.

  The rotary diffusion element 42 includes a diffuse reflection plate 52 and a drive motor 53 for rotating the diffusion reflection plate 52. The diffuse reflection plate 52 diffusely reflects the circularly polarized light beam BLc 1 emitted from the second pickup optical system 41 toward the PBS 27. It is preferable that the diffuse reflection plate 52 causes Lambertian reflection of the light beam BLc1 incident on the diffuse reflection plate 52. The rotation axis of the drive motor 50 is disposed substantially parallel to the optical axis AX0. Thereby, the diffuse reflection plate 52 can be rotated in a plane intersecting the optical axis of the light incident on the diffuse reflection plate 52. The diffuse reflection plate 52 is formed, for example, in a circular shape when viewed from the direction of the rotation axis, but the shape of the diffuse reflection plate 52 is not limited to a circular plate, and may be a flat plate. In the present embodiment, the diffuse reflector 52 corresponds to a “diffuse light generating element” recited in the claims.

  The circularly polarized light (for example, counterclockwise circularly polarized light) BLc2 (diffused light) reflected by the diffuse reflector 52 is transmitted again through the second pickup optical system 41 and the phase difference plate 26b, and is S-polarized light. BLp1.

  By the way, in the present embodiment, the P-polarized light beam BLp separated from the reduced light beam K1s has a relatively strong light intensity at the center as in the reduced light beam K1s. That is, the circularly polarized light beam BLc1 transmitted through the phase difference plate 26b also has a relatively strong light intensity at the center.

  For this reason, in the first and second pickup lenses 41a and 41b, the light beam BLc1 increases in the amount of incident light on the lens central portion where the influence of aberration is small, and decreases in the amount of incident light on the lens peripheral portion where the influence of aberration is large. .

  Since the light beam BLc1 is not easily affected by the aberration, the light condensing state on the rotary diffusion element 42 by the second pickup optical system 41 can be improved. Therefore, since the light beam BLc2 (diffused light) is efficiently generated in the rotary diffusing element 42, the S-polarized light beam BLp1 can be generated efficiently.

  Further, the P-polarized light beam BLp (light beam BLc1) changes only the light intensity at the peripheral portion while keeping the light intensity at the central portion constant by adjusting the rotation angle of the optical axis of the phase difference plate 26a. Can do. Therefore, it is possible to adjust the brightness of the light beam BLc2 (diffused light) while suppressing the influence of the aberration caused by the second pickup optical system 41.

  The yellow fluorescent light YL emitted from the phosphor layer 47 and the light beam BLp1 (blue light) emitted from the rotary diffusing element 42 are combined by the PBS 27 to become white illumination light WL. The illumination light WL is incident on the uniform illumination optical system 40 shown in FIG.

  According to the illuminating device 2 of the present embodiment, a large amount of light is incident on the central portion where the influence of aberration is small in the first and second pickup optical systems 28 and 41, so that the light is collected on the phosphor layer 47 and the diffuse reflector 52. The light state can be improved. Therefore, the bright illumination light WL can be illuminated by generating the bright fluorescence YL in the phosphor layer 47 and generating the bright light beam BLc2 (diffused light) in the rotating diffusion element 42. Therefore, according to the projector 1 provided with this illuminating device 2, a bright image can be displayed.

(Modification)
The beam width compression means 73 of the above embodiment includes the first and second reflecting elements 75a and 75d, the first and second polarization separation elements 75b and 75c, and the first and second phase difference elements 74a and 74b. And the prism (first to third prisms 61, 62, 63) is taken as an example, but the configuration of the light beam width compression means is not limited to this.

  For example, without using a prism, only the first and second reflection elements 75a and 75d, the first and second polarization separation elements 75b and 75c, and the first and second phase difference elements 74a and 74b are used. The light beam width compressing means 73A may be configured by using it. In this case, a strip-shaped mirror having a length in the Z direction may be used as the first and second reflecting elements 75a and 75d. As the first and second polarization separation elements 75b and 75c, a strip-shaped PBS having a length in the Z direction may be used. The first and second reflection elements 75a and 75d and the first and second polarization separation elements 75b and 75c are held in a housing of the lighting device 2 (not shown), for example. The first and second phase difference elements 74a and 74b may be held in a housing (not shown), and fixed to the first and second polarization separation elements 75b and 75c via an adhesive (not shown). You may do it.

  In addition, this invention is not limited to the content of the said embodiment, In the range which does not deviate from the main point of invention, it can change suitably.

  For example, in the above-described embodiment, the projector 1 including the three light modulation devices 4R, 4G, and 4B is exemplified. However, the projector 1 can be applied to a projector that displays a color image with one liquid crystal light modulation device. A digital mirror device may be used as the light modulation device.

  Moreover, although the example which mounted the illuminating device by this invention in the projector was shown in the said embodiment, it is not restricted to this. The lighting device according to the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2 ... Illuminating device, 4B, 4G, 4R ... Light modulator, 6 ... Projection optical system, 25 ... Homogenizer optical system, 26a ... Phase difference plate (3rd phase difference element), 27 ... PBS (1st 3), 28a ... first pickup lens (condensing lens), 28b ... second pickup lens (condensing lens), 41a ... first pickup lens (condensing lens), 41b ... second Pickup lens (condensing lens), 47 ... phosphor layer (diffuse light generation element), 52 ... diffuse reflector (diffuse light generation element), 71 ... light source device, 73, 73A ... light beam width compression means (beam bundle compression) Optical system), 74 ... polarization conversion unit, 74a ... first phase difference element, 74b ... second phase difference element, 75 ... optical path changing unit, 75a ... first reflection element, 75b ... first polarization separation element , 75c ... second deviation Separating element, 75d ... second reflecting element, BR1 ... light beam train (first light beam train), BR2 ... light beam train (second light beam train), BR3 ... light beam train (third light beam) Column), BR4... Light beam train (fourth light beam train), BR5... Light beam train (fifth light beam train), K1.

Claims (5)

A light source device that emits a light bundle including first to fourth light beam arrays in a first polarization state;
A collimating optical system on which the light beam is incident;
A light beam compression optical system provided in a subsequent stage of the collimating optical system;
A light intensity uniformizing optical system provided at a subsequent stage of the light beam compression optical system;
A condensing lens provided at a subsequent stage of the light intensity uniformizing optical system;
A diffused light generating element provided at a subsequent stage of the condenser lens,
The light bundle compression optical system includes a polarization conversion unit and an optical path changing unit,
In the optical path changing unit, a first reflection element, a first polarization separation element, a second polarization separation element, and a second reflection element are arranged in this order,
The polarization conversion unit includes a first phase difference element provided on an upper stage of the first polarization separation element, and a second phase difference element provided on an upper stage of the second polarization separation element. ,
The first to fourth light beam rows are arranged in this order in the upper stage of the light beam compression optical system,
The first light beam train is reflected by the first reflecting element toward the first polarization separating element;
The second light beam train is transmitted through the first retardation element,
The third light beam train is transmitted through the second retardation element,
The fourth light beam row is reflected by the second reflection element toward the second polarization separation element,
The first polarization separation element combines the first light beam train with the second light beam train;
The second polarization separation element synthesizes the fourth light beam train with the third light beam train. 2. The illumination device according to claim 1, wherein the first light beam row and the fourth light beam row are arranged in a central portion of the light beam in a lower stage of the light beam compression optical system. A cross section of each of the plurality of light beams constituting the first light beam row has a major axis direction in a direction in which the plurality of light beams are arranged,
The lighting device according to claim 1, wherein the first reflecting element has a longitudinal direction in a direction in which the plurality of light beams are arranged. The light bundle further includes a fifth light beam train made of linearly polarized light,
A third phase difference element provided in an optical path between the optical path changing unit and the condenser lens;
The illumination device according to any one of claims 1 to 3, further comprising: a third polarization separation element provided in an optical path between the third phase difference element and the condenser lens. The lighting device according to any one of claims 1 to 4,
A light modulation device for generating image light by modulating light from the illumination device according to image information;
A projection optical system that projects the image light.

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