JP2016173391A - Lighting device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device with high light utilization efficiency, and a projector including the lighting device.SOLUTION: The lighting device includes: a light source that outputs a beam of light; a diffuse reflection element on which at least a part the beam light which is output from the light source is incident as predetermined polarized light; a drive element that drives the diffuse reflection element so as to change the travelling direction of the reflectance from the diffuse reflection element as time passes; a pickup lens on which the reflectance incident; and a superposition optical system on which the reflectance passing through the pickup lens is incident.SELECTED DRAWING: Figure 1

Description

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

  2. Description of the Related Art Conventionally, a light source device that irradiates a phosphor layer with excitation light emitted from a light source such as a laser and uses light emitted from the phosphor layer as illumination light is known (for example, see Patent Document 1 below). In this light source device, in order to eliminate speckle noise, blue light which is a part of excitation light is diffused by a transmissive diffusion plate.

JP 2013-250494 A

  However, when the diffusion angle of the transmission type diffusing plate is increased, not only is the loss of light increased, but the polarization state is greatly disturbed by the reflection of light multiple times. As described above, when the polarization state of light is disturbed, there is a problem that the component reflected by the dichroic mirror is reduced and the light use efficiency is lowered.

  One embodiment of the present invention has been made to solve the above-described problem, and an object thereof is to provide an illumination device with high light use efficiency. Another object of one embodiment of the present invention is to provide a projector including the above lighting device.

  According to the first aspect of the present invention, a light source that emits light, a diffuse reflection element in which at least a part of the light emitted from the light source is incident as a predetermined polarization, and reflected light from the diffuse reflection element A drive element that drives the diffuse reflection element, a pickup lens that receives the reflected light, and a superposition optical system that receives the reflected light that has passed through the pickup lens, so that the traveling direction changes with time. A lighting device is provided.

  According to this configuration, since the incident area of the reflected light on the superimposing optical system moves in time, when the time average is performed, compared to the case where the incident area is fixed, the superimposing optical system has a wider area. Reflected light is incident. That is, even if a diffuse reflection element having a relatively small diffusion angle is used, the reflected light can be incident on a wide area as in the case of using a diffusion element having a large diffusion angle. Therefore, a diffuse reflection element having a small diffusion angle can be used instead of a diffusion element having a large diffusion angle. Therefore, since the disturbance of the polarization state in the reflected light is relatively small, the loss caused by the disturbance of the polarization state is suppressed, and as a result, high light utilization efficiency can be obtained.

In the first aspect, the polarization separation element that separates the light into the first light and the second light, the phosphor layer that receives the first light and emits fluorescence, and the second light A phase difference plate provided between the polarization separation element and the diffuse reflection element on the optical path; and the pickup lens includes the polarization separation element and the optical path on the optical path of the second light. The reflection light is provided between the diffuse reflection element and the reflected light is incident on the polarization separation element via the retardation plate, and the polarization separation element combines the fluorescence and the reflection light to generate a third The light is emitted as light, and the superimposing optical system is preferably provided on the optical path of the third light.
According to this configuration, since the reflected light that is reflected by the diffuse reflection element and enters the polarization separation element has a predetermined polarization, the reflected light is combined with the fluorescence with high efficiency by the polarization separation element.

In the first aspect, it is preferable that the diffuse reflection element is provided at a focal position of the pickup lens.
According to this configuration, the traveling direction of the reflected light is converted into a predetermined direction by the pickup lens regardless of the reflection angle of the diffuse reflection element. Thereby, the reflected light enters the superimposing optical system at an appropriate angle.

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

  Since the projector according to the second aspect includes the illumination device according to the first aspect, it is possible to realize a projector with excellent display quality using high-output fluorescence.

1 is a diagram illustrating a schematic configuration of a projector according to a first embodiment. The figure which shows schematic structure of an illuminating device. The figure which showed the illumination area | region formed on an integrator optical system. The figure which showed the relationship between the drive direction of a diffuse reflection element, and the change of the position of an illumination area. The figure which showed the illumination area | region formed on a lens array. FIG. 6 is a diagram illustrating a schematic configuration of a projector according to a second embodiment.

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 embodiment)
First, an example of a projector according to the present embodiment will be described. The projector of this embodiment is a projection type image display device that displays a color image on a screen (projected surface) SCR. The projector 1 uses three light modulation devices corresponding to each color light of red light, green light, and blue light. The projector uses a semiconductor laser (laser light source) that can obtain light with high luminance and high output as the light source of the illumination device.

(projector)
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 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. It has.

  The color separation optical system 3 separates the illumination light WL into red light LR, green light LG, and 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 from the illumination device 2 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 an array light source (light source) 21A, a collimator optical system 22, an afocal optical system 23, a homogenizer optical system 24, and an optical element 25A including a polarization separation element 50A. The first condensing optical system 26, the fluorescent light emitting element 27, the phase difference plate 28, the second condensing optical system 29, the diffuse reflection element 30, the integrator optical system 31, and the polarization conversion element 32 And a superimposing lens 33a. In the present embodiment, the integrator optical system 31 constitutes the superimposing optical system 33 in cooperation with the superimposing lens 33a.

  An array light source 21A, a collimator optical system 22, an afocal optical system 23, a homogenizer optical system 24, an optical element 25A, a phase difference plate 28, a second condensing optical system 29, and a diffuse reflection element 30 Are sequentially arranged on the optical axis ax1. On the other hand, the fluorescent light emitting element 27, the first condensing optical system 26, the optical element 25A, the integrator optical system 31, the polarization conversion element 32, and the superimposing lens 33a are sequentially arranged on the optical axis ax2. Has been. The optical axis ax1 and the optical axis ax2 are in the same plane and are orthogonal to each other.

  The array light source 21A corresponds to the light source in the claims. The array light source 21 </ b> A includes a first semiconductor laser 211 and a second semiconductor laser 212. The plurality of first semiconductor lasers 211 and the plurality of second semiconductor lasers 212 are arranged in an array in one plane orthogonal to the optical axis ax1.

  The first semiconductor laser 211 emits blue light BL ′. The first semiconductor laser 211 emits laser light having a peak wavelength of 460 nm, for example, as blue light BL ′. The second semiconductor laser 212 is a laser light source for excitation light that emits excitation light BL. The second semiconductor laser 212 emits laser light having a peak wavelength of 440 nm, for example, as the excitation light BL.

  The excitation light BL and the blue light BL ′ are emitted from the array light source 21A toward the polarization separation element 50A.

  Excitation light BL and blue light BL ′ emitted from the array light source 21 </ b> A enter the collimator optical system 22. The collimator optical system 22 converts each of the excitation light BL and the blue light BL ′ emitted from the array light source 21 </ b> A into parallel light beams. The collimator optical system 22 is composed of, for example, a plurality of collimator lenses 22a arranged in an array. The plurality of collimator lenses 22a are arranged corresponding to the plurality of first semiconductor lasers 211 and the plurality of second semiconductor lasers 212, respectively.

  Each excitation light BL and blue light BL ′ that has passed through the collimator optical system 22 enters the afocal optical system 23. The afocal optical system 23 adjusts the beam diameters of the excitation light BL and the blue light BL ′. The afocal optical system 23 includes, for example, a convex lens 23a and a concave lens 23b.

  The excitation light BL and blue light BL ′ that have passed through the afocal optical system 23 are incident on the homogenizer optical system 24. The homogenizer optical system 24 includes a first multi-lens array 24a and a second multi-lens array 24b. The first multi-lens array 24a includes a plurality of small lenses 24am, and the second multi-lens array 24b includes a plurality of small lenses 24bm corresponding to the plurality of small lenses 24am.

  The excitation light BL and blue light BL ′ that have passed through the homogenizer optical system 24 are incident on the optical element 25A. The optical element 25A is composed of, for example, a dichroic prism having wavelength selectivity. The dichroic prism has an inclined surface K that forms an angle of 45 ° with the optical axis ax1. The inclined surface K forms an angle of 45 ° with respect to the optical axis ax2.

  On the inclined surface K, a polarization separation element 50A having wavelength selectivity is provided. The polarization separation element 50A separates the excitation light BL and the blue light BL 'into an S polarization component and a P polarization component for the polarization separation element 50A.

  Further, the polarization separation element 50A has a color separation function of transmitting fluorescence YL having different wavelength bands between excitation light BL and blue light BL ′, which will be described later, regardless of the polarization state.

  Here, the excitation light BL and the blue light BL ′ are coherent linearly polarized light. Further, the excitation light BL and the blue light BL 'have different polarization directions when entering the polarization separation element 50A.

  Specifically, the polarization direction of the excitation light BL coincides with the polarization direction of the S polarization component reflected by the polarization separation element 50A. On the other hand, the polarization direction of the blue light BL ′ coincides with the polarization direction of the P-polarized light component transmitted through the polarization separation element 50A.

  Therefore, the excitation light BL is reflected toward the fluorescent light emitting element 27 by the polarization separation element 50A as S-polarized excitation light BLs. On the other hand, the blue light BL ′ passes through the polarization separation element 50 </ b> A toward the diffuse reflection element 30 as P-polarized blue light BL′p. The S-polarized excitation light BLs corresponds to the first light in the claims, and the P-polarized blue light BL'p corresponds to the second light in the claims.

  The S-polarized excitation light BLs emitted from the polarization separation element 50 </ b> A is incident on the first condensing optical system 26. The first condensing optical system 26 condenses a plurality of light beams (excitation light BLs) emitted from the second multi-lens array 24 b toward the phosphor layer 34, and on the phosphor layer 34. Superimpose each other.

  The first condensing optical system 26 includes, for example, a first lens 26a and a second lens 26b. The excitation light BLs emitted from the first condensing optical system 26 enters the fluorescent light emitting element 27. The fluorescent light emitting element 27 includes a phosphor layer 34, a substrate 35 that supports the phosphor layer 34, and a fixing member 36 that fixes the phosphor layer 34 to the substrate 35.

  In the present embodiment, the phosphor layer 34 is fixed to the substrate 35 by a fixing member 36 provided between the side surface of the phosphor layer 34 and the substrate 35. The surface of the phosphor layer 34 opposite to the side on which the excitation light BLs is incident is in contact with the substrate 35.

  The phosphor layer 34 includes a phosphor that is excited by absorbing the excitation light BLs having a wavelength of 440 nm. The phosphor excited by the excitation light BLs emits fluorescence (yellow light) YL having a peak wavelength in a wavelength region of 500 to 700 nm, for example.

  It is preferable to use a material having excellent heat resistance and surface processability for the phosphor layer 34. As such a phosphor layer 34, for example, a phosphor layer in which phosphor particles are dispersed in an inorganic binder such as alumina, or a phosphor layer in which phosphor particles are sintered without using a binder is suitable. Can be used.

  On the side of the phosphor layer 34 opposite to the side on which the excitation light BLs is incident, a reflecting portion 37 as a first reflecting element is provided. The reflection unit 37 reflects a component traveling toward the substrate 35 in the fluorescence YL generated in the phosphor layer 34.

  A heat sink 38 is disposed on the surface of the substrate 35 opposite to the surface that supports the phosphor layer 34. In the fluorescent light emitting element 27, since heat can be radiated through the heat sink 38, thermal deterioration of the phosphor layer 34 can be prevented.

  Among the fluorescence YL generated in the phosphor layer 34, a part of the fluorescence YL is reflected by the reflecting portion 37 and emitted to the outside of the phosphor layer 34. In addition, among the fluorescence YL generated in the phosphor layer 34, another part of the fluorescence YL is emitted outside the phosphor layer 34 without passing through the reflection portion 37. In this way, the fluorescence YL is emitted from the phosphor layer 34.

  The fluorescence YL emitted from the phosphor layer 34 is non-polarized light. The fluorescence YL passes through the first condensing optical system 26 and then enters the polarization separation element 50A. The fluorescence YL travels from the polarization separation element 50 </ b> A toward the integrator optical system 31.

  The P-polarized blue light BL′p emitted from the polarization separation element 50 </ b> A enters the phase difference plate 28. The phase difference plate 28 is composed of a quarter-wave plate disposed in the optical path (the optical path of the second light) between the polarization separation element 50A and the diffuse reflection element 30. Therefore, the P-polarized blue light BL′p emitted from the polarization separation element 50A is converted into, for example, clockwise circularly-polarized blue light BLc1 by the phase difference plate 28, and then the second condensing optical system. 29 is incident.

  The second condensing optical system 29 includes, for example, a pickup lens 29 a and condenses the blue light BLc 1 toward the diffuse reflection element 30.

  The diffuse reflection element 30 diffuses and reflects the blue light BLc1 (part of the light emitted from the array light source 21A) emitted from the second condensing optical system 29 toward the polarization separation element 50A. The light diffusely reflected by the diffuse reflection element 30 is referred to as blue light BLc2.

  By the way, in order to prevent the occurrence of color unevenness in the projector 1, the intensity distribution of the blue light BL's on the light incident surface of the lens array 31a constituting the superimposing optical system 33 together with the superimposing lens 33a is equal to the intensity distribution of the fluorescence YL. Good. Here, the fluorescence YL emitted from the phosphor layer 34 has a light distribution similar to the light distribution of the Lambertian reflected light. In the present specification, the light distribution of the Lambertian reflected light is referred to as a Lambertian light distribution. The blue light BLc2 reflected by the diffuse reflection element 30 may also have a Lambertian light distribution.

However, for example, when the diffusion angle of the diffuse reflection element 30 is increased, the polarization state of light is disturbed as described later, and there is a possibility that the light utilization efficiency is lowered.
In the present embodiment, the diffuse reflection element 30 diffusely reflects predetermined polarized light (clockwise circularly polarized blue light BLc1) incident from the second condensing optical system 29.

  The clockwise circularly polarized blue light BLc1 is reflected as the counterclockwise circularly polarized blue light BLc2 once reflected by the diffuse reflection element 30, and further converted into S-polarized blue light BL's by the phase difference plate 28. Is done. In this case, the S-polarized blue light BL's diffusely reflected by the diffuse reflection element 30 is reflected toward the integrator optical system 31 by the polarization separation element 50A.

  However, when the diffusion angle of the diffuse reflection element 30 is large, the blue light BLc1 may be reflected twice by the diffuse reflection element 30. Then, the clockwise circularly polarized blue light BLc1 becomes a counterclockwise circularly polarized light by the first reflection, but becomes a clockwise circularly polarized light again by the second reflection, resulting in the clockwise circularly polarized light. The blue light BLc2 enters the phase difference plate 28. The clockwise circularly polarized blue light BLc2 is converted into P-polarized blue light by the phase difference plate. In this case, the P-polarized blue light diffusely reflected by the diffuse reflection element 30 cannot be reflected toward the integrator optical system 31 by the polarization separation element 50A and is transmitted through the polarization separation element 50A. Therefore, the light from the array light source 21A cannot be used efficiently.

  On the other hand, in the present embodiment, a diffuse reflection element 30 having a diffusion angle enough to reflect the blue light BLc1 once is used.

  According to the present embodiment, the double reflection of the blue light BLc1 by the diffuse reflection element 30 is suppressed. Therefore, the blue light BLc1 is reflected by the diffuse reflection element 30 so that the counterclockwise circularly polarized blue light BLc2 is excellent. Converted. The counterclockwise circularly polarized blue light BLc2 is converted into S-polarized blue light BL's by the phase difference plate 28. Therefore, the blue light BLc2 reflected by the diffuse reflection element 30 is reflected toward the integrator optical system 31 by the polarization separation element 50A with high efficiency.

  The blue light BL's and the fluorescence YL are combined by the polarization separation element 50A, and illumination light (white light) WL is generated. The illumination light WL is emitted toward the integrator optical system 31. The illumination light WL corresponds to “third light” in the claims.

  The illumination light WL emitted from the polarization separation element 50A enters the integrator optical system 31. The integrator optical system 31 includes, for example, a lens array 31a and a lens array 31b. The lens arrays 31a and 31b are composed of a plurality of small lenses arranged in an array.

  The illumination light WL that has passed through the integrator optical system 31 enters the polarization conversion element 32. The polarization conversion element 32 includes a polarization separation film and a retardation plate. The polarization conversion element 32 converts the non-polarized fluorescence YL into S-polarized light.

  The illumination light WL transmitted through the polarization conversion element 32 is superimposed in the illuminated area by the superimposing lens 33a.

  As described above, the diffuse reflection element 30 of the present embodiment has a relatively small diffusion angle (diffusion capability). Therefore, as shown in FIG. 3, the blue light BL's forms a spot SA at a part on the lens array 31a, for example, at the center of the lens array 31a. On the other hand, since the fluorescence YL has a Lambertian light distribution, a relatively uniform illuminance distribution is formed over the entire lens array 31a.

  As described above, when the illuminance of the blue light BL's is largely biased over the entire lens array 31a, the illuminance of the blue light BL's and the illuminance of the fluorescent light YL in the illuminated area is increased even when the superimposing optical system 33 is used. Since they do not match, color unevenness occurs.

  On the other hand, in the present embodiment, the position of the spot SA formed on the lens array 31a is moved in time so that the illuminance of the blue light BL's on the lens array 31a is obtained when time-averaged. The bias is reduced. As a result, color unevenness in the illuminated area is reduced.

  Specifically, the illuminating device 2 of the present embodiment includes a drive element 110 that drives the diffuse reflection element 30 so that the traveling direction of the blue light BLc2 changes with time. The drive element 110 is composed of, for example, a piezo element or an actuator. The drive element 110 changes the traveling direction of the reflected light by inclining the diffuse reflection element 30 in a predetermined direction.

  4A to 4D are diagrams showing the relationship between the change in the driving direction of the diffuse reflection element 30 (the traveling direction of the reflected light) and the change in the position of the spot SA. Specifically, FIG. 4A is a diagram showing spots SA formed on the lens array 31a when the diffuse reflection element 30 is not tilted. FIGS. 4B to 4D are diagrams showing spots SA formed on the lens array 31a when the diffuse reflection element 30 is tilted.

  4A to 4D, description will be made using an XYZ coordinate system for easy understanding. As shown in FIG. 4A, when the diffuse reflection element 30 is not inclined, the XY plane defines a plane parallel to the reflection surface 30a of the diffuse reflection element 30, and the Z direction is a direction orthogonal to the reflection surface 30a. Is specified. 4A to 4D, the surface (light incident surface) of the lens array 31a is assumed to be parallel to the XY plane in order to simplify the description.

  As shown in FIG. 4A, when the driving element 110 holds the diffuse reflection element 30 so that the reflection surface 30a is parallel to the XY plane, the reflected light from the reflection surface 30a is emitted in the Z direction. . And spot SA is formed in the center area | region of the surface of the lens array 31a.

  FIG. 4B shows a state in which the drive element 110 rotates the reflecting surface 30a clockwise around the Y axis and rotates the reflecting surface 30a clockwise around the X axis. In this case, the reflected light from the reflecting surface 30a is inclined in the + X direction with respect to the Z-axis direction when viewed from the Y-axis direction, and proceeds in the direction inclined in the + Y direction with respect to the Z-axis direction when viewed from the X-axis direction. Then, a spot SA is formed in the upper right area on the surface of the lens array 31a.

  FIG. 4C shows a state in which the driving element 110 rotates the reflecting surface 30a clockwise around the Y axis and rotates the reflecting surface 30a counterclockwise around the X axis. . In this case, the reflected light from the reflecting surface 30a is inclined in the + X direction with respect to the Z axis direction when viewed from the Y axis direction, and proceeds in the direction inclined in the −Y direction with respect to the Z axis direction when viewed from the X axis direction. . Then, a spot SA is formed in the lower right region of the surface of the lens array 31a.

  FIG. 4D shows a state in which the driving element 110 rotates the reflecting surface 30a counterclockwise around the Y axis and rotates the reflecting surface 30a counterclockwise around the X axis. Yes. In this case, the reflected light from the reflecting surface 30a is inclined in the −X direction with respect to the Z axis direction when viewed from the Y axis direction, and is inclined in the −Y direction with respect to the Z axis direction when viewed from the X axis direction. move on. Then, a spot SA is formed in the lower left area of the surface of the lens array 31a.

  Based on such a configuration, the driving element 110 changes the traveling direction of the blue light BLc2 in time by tilting the reflecting surface 30a, and changes the position of the spot SA formed on the lens array 31a in time. It is possible to move.

  In the present embodiment, as shown in FIG. 5, the driving element 110 drives the diffuse reflection element 30 so that the substantially entire surface of the light incident surface of the lens array 31 a is scanned by the spot SA. This state is equivalent to that the blue light BL's is incident on substantially the entire light incident surface of the lens array 31a in terms of time average. If time averaged, a substantially uniform illuminance distribution is formed on the light incident surface of the lens array 31a.

  Incidentally, the lens array 31a includes a plurality of first small lenses, and the lens array 31b includes a plurality of second small lenses. The plurality of first small lenses and the plurality of second small lenses have a one-to-one correspondence. The blue light BL's is divided into a plurality of small light beams by the plurality of first small lenses. The small luminous flux corresponding to the first small lens enters the second small lens corresponding to the first small lens, and further enters a predetermined area of the polarization conversion element 32. In order for the blue light BL ′s incident on the lens array 31a to be incident on the polarization conversion element 32 with high efficiency, the small luminous flux corresponding to the first small lens is appropriate for the second small lens corresponding to the first small lens. It is better to enter at a certain angle. For this purpose, the blue light BL's should be incident on the lens array 31a at a constant angle regardless of the inclination of the reflecting surface 30a.

  When the reflecting surface 30a is inclined as shown in FIGS. 4B to 4D, the blue light BLc2 is emitted in a direction inclined from the Z-axis direction. Further, the direction in which the blue light BLc2 travels varies depending on the tilt direction of the reflecting surface 30a. In the present embodiment, the position where the principal ray of the blue light BLc1 is incident on the reflecting surface 30a is provided at the focal position of the second condensing optical system 29. The direction in which the light BLc2 travels is adjusted in a predetermined direction by the second condensing optical system 29. Specifically, since the blue light BLc2 is emitted from the focal position of the second condensing optical system 29, after passing through the second condensing optical system 29, regardless of the inclination direction of the reflecting surface 30a, Proceeding in parallel with the optical axis of the second condensing optical system 29 (Z-axis direction). Therefore, the blue light BL's reflected by the polarization separation element 50A is incident on the lens array 31a at a constant angle regardless of the tilt direction of the reflecting surface 30a. Therefore, the blue light BL′p, which is the second light, is used as the illumination light WL with high efficiency.

According to this embodiment, the following effects can be obtained.
Even when the diffuse reflection element 30 having a relatively small diffusion angle is used, the illuminance bias of the blue light BL ′s on the light incident surface of the integrator optical system 31 can be reduced. Further, since the fluorescence YL has a Lambertian light distribution, the illuminance deviation of the fluorescence YL on the light incident surface of the integrator optical system 31 is small. Therefore, the color unevenness in the illuminated area is sufficiently reduced. Since the blue light BLc1 that is circularly polarized light is favorably converted to the circularly polarized blue light BLc2 that is reversely rotated by the diffuse reflection element 30, the blue light BL′p is used as the illumination light WL with high efficiency.
Since the position where the chief ray of the blue light BLc1 enters the reflecting surface 30a is provided at the focal position of the second condensing optical system 29, the blue light BL′p is used as the illumination light WL with high efficiency. .

(Second Embodiment)
FIG. 6 is a diagram illustrating a schematic configuration of a projector 1A according to the second embodiment. Members common to the projector 1 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The projector 1A includes a first lighting device 2A and a second lighting device 2B instead of the lighting device 2.

In the present embodiment, the first lighting device 2A emits light including red light and green light, and the second lighting device 2B emits blue light.
As shown in FIG. 6, the first illumination device 2 </ b> A includes a light source device 10, a condensing optical system 20, a rotating fluorescent plate 230, a motor 50, an integrator optical system 131, a polarization conversion element 32, and a superimposing optical system 133.

  The light source device 10 includes an excitation laser light source that emits excitation light BL1. The condensing optical system 20 includes a first lens 122 and a second lens 124, and condenses the excitation light BL1 on the phosphor layer 46 of the rotating fluorescent plate 230. The motor 50 suppresses the temperature rise of the phosphor layer 46 by rotating the rotating fluorescent plate 230.

  The phosphor layer 46 included in the rotating fluorescent plate 230 converts the excitation light BL1 from the light source device 10 into yellow fluorescence YL including red light and green light. On the substrate side of the phosphor layer 46, a dichroic mirror 47 that transmits the excitation light BL1 and reflects the fluorescence YL is formed. In the present embodiment, the excitation light BL1 incident on the phosphor layer 46 is converted into fluorescence YL without passing through the phosphor layer 46.

  The second illumination device 2B includes a light source device 121, a diffuse reflection element 30, a drive element 110, a pickup lens 126, an integrator optical system 31, and a superimposing lens 33a.

  The light source device 121 is a laser light source that emits linearly polarized blue light B. Blue light B is incident on the diffuse reflection element 30.

  As in the first embodiment, the traveling direction of the blue light B reflected by the diffuse reflection element 30 is temporally changed by driving the diffuse reflection element 30 by the drive element 110. Thereby, the position of the spot SA (see FIG. 3) formed on the lens array 131a changes with time.

  Further, similarly to the first embodiment, the diffuse reflection element 30 is provided at the focal position of the pickup lens 126. Specifically, a position where the principal ray of the blue light B is incident on the reflection surface 30 a of the diffuse reflection element 30 is provided at the focal position of the pickup lens 126. Thereby, as in the first embodiment, the blue light B reflected by the diffuse reflection element 30 enters the lens array 31a at a constant angle.

  The blue light B is superimposed on the illuminated area (near the pixel formation area of the light modulation device 4B) by the superimposing lens 33a via the third total reflection mirror 8c and the field lens 10B. Thereby, the illuminated area is illuminated with a substantially uniform illuminance distribution.

  In the present embodiment, the diffuse reflection element 30 has a diffusion angle that is weak enough to reflect the blue light B once. Thereby, disorder of the polarization state that occurs when the blue light B is reflected is suppressed.

Therefore, according to the present embodiment, linearly polarized light (blue light B) in which the polarization state disturbance is suppressed is incident on the light modulation device 4B, so that the incident-side polarizing plate in the light modulation device 4B can be eliminated. Therefore, since the blue light B is not cut by the incident side polarizing plate, the blue light B can be efficiently used in the light modulation device 4R.
Even if an incident-side polarizing plate is provided, the blue light B can be transmitted through the incident-side polarizing plate, so that the blue light B can be efficiently used in the light modulation device 4R.
Therefore, high light utilization efficiency can be realized also in the projector 1A of the present embodiment.

  In addition, this invention is not necessarily limited to the thing of the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.

  For example, although the phosphor layer 34 is fixedly disposed on the substrate 35 in the first embodiment, the phosphor layer may be disposed on a rotating substrate.

  In the first embodiment, the second semiconductor laser 212 that emits laser light having a peak wavelength of 440 nm is used as the laser light source for excitation light, and the laser light having a peak wavelength of 460 nm is used as the laser light source for blue light. Although the case where the first semiconductor laser 211 to be emitted is used is illustrated, the peak wavelengths of the excitation light BL and the blue light BL ′ are not necessarily limited to such an example.

  Moreover, in the said embodiment, although the projector 1 provided with the three light modulation apparatuses 4R, 4G, and 4B was illustrated, it is also possible to apply to the projector which displays a color image | video with one light modulation apparatus.

In addition, the shape, number, arrangement, material, and the like of the various components of the lighting device and the projector are not limited to the above-described embodiment, and can be changed as appropriate.
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 1,1A ... Projector, 4R, 4G, 4B ... Light modulator, 5 ... Composition optical system, 6 ... Projection optical system, 21A ... Array light source (light source), 28 ... Phase difference plate, 29a, 126 ... Pick-up lens, 30 , 130 ... Diffuse reflection element, 33 ... Superimposing optical system, 34 ... Phosphor layer, 50A ... Polarization separation element, 110 ... Drive element.

Claims (4)

A light source that emits light;
A diffuse reflection element on which at least a part of the light emitted from the light source is incident as predetermined polarized light;
A driving element for driving the diffuse reflection element so that the traveling direction of the reflected light from the diffuse reflection element changes with time;
A pickup lens on which the reflected light is incident;
A superimposing optical system on which the reflected light transmitted through the pickup lens is incident;
A lighting device comprising: A polarization separation element that separates the light into first light and second light;
A phosphor layer that emits fluorescence in response to the first light;
A retardation plate provided between the polarization separation element and the diffuse reflection element on the optical path of the second light;
The pickup lens is provided between the polarization separation element and the diffuse reflection element on the optical path of the second light,
The reflected light is incident on the polarization separation element through the retardation plate,
The polarization separation element combines the fluorescence and the reflected light and emits them as third light,
The illumination device according to claim 1, wherein the superimposing optical system is provided on an optical path of the third light. The illumination device according to claim 1, wherein the diffuse reflection element is provided at a focal position of the pickup lens. The illumination device according to any one of claims 1 to 3,
A light modulation device that forms image light by modulating light emitted from the illumination device according to image information; and
A projection optical system that projects the image light.

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