JP2015060035A - Projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projector capable of reducing speckle by a simple configuration.SOLUTION: In the projector including a light source 10 emitting first color light and second color light, spatial color separation means 15 including a first reflection element 15B and a second reflection element 15R, and a light modulation element 200 on which the first color light and the second color light are incident, the first color light is coherence light, the second color light is non-coherence light, the first reflection element 15B reflects the first color light, and the second reflection element 15R reflects the second color light. The first reflection element 15B temporally changes the optical path of the first color light reflected by the first reflection element 15B.

Description

  The present invention relates to a projector.

  The projector modulates light emitted from the light source unit according to image information with a light modulation device, and enlarges and projects the obtained image with a projection lens. As such a projector, a single-plate projector that generates a desired image by separating white light emitted from a lamp light source into R, G, and B colors and modulating the light with a single liquid crystal panel is known (for example, , See Patent Document 1).

  On the other hand, there is also known a three-plate projector that generates a desired image by modulating light emitted from laser beams corresponding to R, G, and B colors by three liquid crystal panels, respectively (see, for example, Patent Document 2). ). In this three-plate projector, speckle reduction means for reducing speckle due to laser light is arranged in the optical path.

Japanese Patent Laid-Open No. 04-60538 Special table 2011-507042 gazette

  In the projector disclosed in Patent Document 1, it is conceivable to use a light source unit that emits light in which laser light and non-laser light are mixed. Conventionally, in such a case, it has not been assumed that speckle of laser light is reduced by a simple configuration, and provision of a new technique has been desired.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a projector capable of reducing speckles with a simple configuration.

  According to the first aspect of the present invention, the light source that emits the first color light and the second color light, the spatial color separation means having the first reflection element and the second reflection element, and the first color light, In the projector including the light modulation element on which the second color light is incident, the first color light is coherence light, the second color light is non-coherence light, and the first reflection element is The first color light is reflected, the second reflection element reflects the second color light, and the first reflection element follows an optical path of the first color light reflected by the first reflection element. A time-varying projector is provided.

  According to the projector according to the first aspect, since the optical path of the first color light that is coherence light can be temporally changed, different speckle patterns can be temporally superimposed. Therefore, speckle noise due to coherence light can be reduced, and a bright image can be displayed. Moreover, since speckle noise is reduced only by the first reflective element, the apparatus configuration can be simplified.

In the first aspect, the first reflecting element may be a deformable mirror.
According to this configuration, since the reflecting surface of the mirror is deformed by the deformable mirror, speckle noise can be satisfactorily reduced by simply and reliably changing the optical path of the first color light.

In the first aspect, the first reflecting element includes a driving device that temporally changes the optical path length of the first color light between the light source and the incident surface of the first reflecting element. Also good.
According to this configuration, since the optical path length of the first color light between the light source and the incident surface of the first reflective element changes with time by the driving device, the optical path of the first color light can be changed easily and reliably. By doing so, speckle noise can be reduced well.

In the first aspect, the first reflective element temporally changes an angle formed by an incident surface of the first reflective element and an optical axis of the first color light incident on the first reflective element. It is good also as a structure including the drive device to make it.
According to this configuration, the angle between the incident surface of the first reflecting element and the optical axis of the first color light incident on the first reflecting element is changed with time by the driving device. Speckle noise can be satisfactorily reduced by simply and reliably changing the optical path.

In the first aspect, the light source further emits third color light that is non-coherence light, and the spatial color separation means further includes a third reflective element that reflects the third color light, One reflection element may be provided downstream of the second reflection element and the third reflection element.
According to this configuration, for example, an image of three colors (RGB) can be displayed. In this case, since the first reflective element is provided downstream of the second reflective element and the third reflective element, the non-coherent light does not enter the first reflective element. Thus, loss due to non-coherent light passing through the first reflective element is prevented, and non-coherent light can be used efficiently.

In the first aspect, the coherence light may be laser light, and the non-coherence light may be fluorescence generated by excitation of the laser light.
According to this configuration, in a projector using a light source in which laser light and fluorescence are mixed, speckle can be reduced with a simple configuration.

FIG. 2 is a plan view illustrating a schematic configuration of the projector according to the first embodiment. (A) is a side view of the light source device according to the first embodiment, and (b) is a top view of the light source device according to the first embodiment. The figure which shows schematic structure of the light source device which concerns on 1st Embodiment. (A) thru | or (c) is a top view which shows each structural example of the light-emitting body layer with which the fluorescence light emitting element concerning 1st Embodiment is provided. (A) is sectional drawing which shows the principal part structure of a dichroic mirror, (b) is operation | movement explanatory drawing of a dichroic mirror. The operation explanatory view of a dichroic mirror. The figure which shows the structure which concerns on the modification regarding arrangement | positioning of a piezoelectric element. (A) is a figure which shows the planar structure of the light modulation apparatus which concerns on 1st Embodiment, (b) is a figure which shows the structure of one pixel. (A) is a figure which shows the relationship between the micro light beam and a sub pixel by a prior art, (b) is a figure which shows the relationship between the micro light beam and sub pixel which concern on 1st Embodiment. The top view which shows schematic structure of a light-shielding member. (A), (b) is a figure which shows schematic structure of the dichroic mirror which concerns on 2nd Embodiment. The figure which shows schematic structure of the dichroic mirror which concerns on 3rd Embodiment. The figure for demonstrating the effect | action by the dichroic mirror which concerns on 3rd 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)
The projector according to the present embodiment is a projection-type image display device that displays a color image (image) on a screen (projected surface). The projector according to the present embodiment uses a laser light source such as a semiconductor laser (LD) that can obtain light with high luminance and high output as the light source of the illumination device.

(projector)
The configuration of the projector will be described. FIG. 1 is a plan view showing a schematic configuration of the projector according to the first embodiment.

  As shown in FIG. 1, the projector 1 includes a light source unit 100, a light modulation device (light modulation element) 200, and a projection optical system 300. In the projector 1, an axis on which the light source unit 100, the light modulation device 200, and the projection optical system 300 are arranged is an optical axis ax.

  The light modulation device 200 is a single plate type liquid crystal light modulation device using, for example, one liquid crystal display panel. By adopting such a single plate type liquid crystal light modulation device, the projector 1 can be miniaturized. The light modulation device 200 modulates the illumination light from the light source unit 100 according to image information to form image light.

  A light incident side polarizing plate 201 a is provided on the surface of the light modulation device 200 facing the light source unit 100. Further, a light emission side polarizing plate 201b is provided on the side of the light modulation device 200 facing the projection optical system 300. The light incident side polarizing plate 201a and the light emitting side polarizing plate 201b have mutually orthogonal polarization axes.

  The projection optical system 300 includes a projection lens, and enlarges and projects the image light modulated by the light modulation device 200 toward the screen SCR. The number of lenses constituting the projection optical system may be one or a plurality.

(Light source unit)
Next, a specific configuration of the light source unit 100 will be described. In the following description, the description may be made using an XYZ orthogonal coordinate system. In this case, the Y direction corresponds to the vertical direction of the light source unit 100, the Z direction is a direction parallel to the optical axis ax1, and the X direction is a direction parallel to the optical axis ax.

  2A and 2B are diagrams illustrating a schematic configuration of the light source unit 100. FIG. 2A illustrates the light source unit 100 from the side surface (X direction), and FIG. 2B illustrates the light source unit 100 from the top surface (Y direction). It is the figure seen from.

  As shown in FIGS. 2A and 2B, the light source unit 100 includes a light source device (light source) 10, a collimator optical system 11, a light beam shaping device 12, and a light shielding member (regulating member) 13. An optical system 14, a color separation element (space separation means) 15, and a microlens array 16 are provided.

  In the light source unit 100, the light source device 10, the collimator optical system 11, the light beam shaping device 12, and the light shielding member 13 are arranged on one optical axis ax1 among the optical axes ax1 and ax that are orthogonal to each other in the same plane. The superimposing optical system 14 and the color separation element 15 are arranged in this order. On the other optical axis ax, the color separation element 15 and the microlens array 16 are arranged in this order.

FIG. 3 is a diagram illustrating a schematic configuration of the light source device 10.
As shown in FIG. 3, the light source device 10 includes an array light source 121, a collimator optical system 122, an afocal optical system 123, a homogenizer optical system 124, an optical element 125A including a polarization separation element 150A, a phase difference, and the like. A plate 126, a pickup optical system 127, a fluorescent light emitting element 128, an integrator optical system 129, a polarization conversion element 130, and a superimposing optical system 131 are roughly provided.

  The array light source 121 is formed by arranging a plurality of semiconductor lasers 121a. Specifically, a plurality of semiconductor lasers 121a are arranged in an array in a plane orthogonal to the optical axis. The optical axis of the array light source 121 is defined as an optical axis ax2. In addition, an optical axis of light emitted from a fluorescent light emitting element 128 (described later) toward the color separation optical system 3 side is an optical axis ax1. The optical axis ax1 and the optical axis ax2 are in the same plane and are orthogonal to each other. On the optical axis ax1, the fluorescent light emitting element 128, the pickup optical system 127, the phase difference plate 126, the optical element 125A, the integrator optical system 129, the polarization conversion element 130, and the superimposing optical system 131 are They are arranged in order. On the other hand, on the optical axis ax2, the array light source 121, the collimator optical system 122, the afocal optical system 123, the homogenizer optical system 124, and the optical element 125A are arranged in this order.

  The semiconductor laser 121a emits excitation light (blue light) BL having a peak wavelength in a wavelength range of 440 to 480 nm, for example, as a first light flux in the first wavelength band. The excitation light BL emitted from each semiconductor laser 121a is coherent linearly polarized light, and is emitted toward the polarization separation element 150A in parallel with the optical axis ax2.

  In the array light source 121, the polarization direction of the excitation light BL emitted from each semiconductor laser 121a is matched with the polarization direction of the polarization component (eg, S polarization component) reflected by the polarization separation element 150A. Then, the excitation light BL emitted from the array light source 121 enters the collimator optical system 122.

  The collimator optical system 122 converts the excitation light BL emitted from the array light source 121 into parallel light. For example, a plurality of collimator lenses 122a arranged in an array corresponding to each semiconductor laser 121a. Consists of. Then, the excitation light BL converted into parallel light by passing through the collimator optical system 122 enters the afocal optical system 123.

  The afocal optical system 123 adjusts the size (spot diameter) of the excitation light BL, and includes, for example, two afocal lenses 123a and afocal lenses 123b. Then, the excitation light BL whose size is adjusted by passing through the afocal optical system 123 enters the homogenizer optical system 124.

  The homogenizer optical system 124 converts the light intensity distribution of the excitation light BL into a uniform state (so-called top hat distribution), and includes, for example, a pair of multi-lens array 124a and multi-lens array 124b. Then, the excitation light BL converted into a uniform light intensity distribution by the homogenizer optical system 124 enters the fluorescent light emitting device 128 via the polarization separation device 150A.

  The optical element 125A is made of, for example, a dichroic prism having wavelength selectivity, and the dichroic prism has an inclined surface K that forms an angle of 45 ° with respect to the optical axis ax1. The inclined surface K forms an angle of 45 ° with respect to the optical axis ax2. Furthermore, the optical element 125A is arranged so that the intersection of the optical axes ax1 and ax2 orthogonal to each other and the optical center of the inclined surface K coincide. The inclined surface K is provided with a polarization separation element 150A having wavelength selectivity.

  The polarization separation element 150A converts the first wavelength band excitation light BL incident on the polarization separation element 150A into an S polarization component (one polarization component) and a P polarization component (the other polarization component) for the polarization separation element 150A. It has a polarization separation function that separates into The polarization separation element 150A reflects the S-polarized component of the excitation light BL and transmits the P-polarized component of the excitation light BL. In addition, the polarization separation element 150A has a color separation function that transmits light having a second wavelength band different from the first wavelength band, out of the light incident on the polarization separation element 150A, regardless of the polarization state. doing. The optical element 125A is not limited to a prism shape such as a dichroic prism, and a parallel plate dichroic mirror may be used.

  The excitation light BL that has entered the polarization separation element 150A is reflected toward the fluorescent light emitting element 128 as S-polarized excitation light BLs because the polarization direction of the excitation light BL coincides with the S-polarized light component.

  The retardation plate 126 is a quarter-wave plate (λ / 4 plate) disposed in the optical path between the polarization separation element 150A and the phosphor layer 132 of the fluorescent light-emitting element 128. The S-polarized (linearly polarized) excitation light BLs incident on the phase difference plate 126 is converted into circularly-polarized excitation light BLc and then incident on the pickup optical system 127.

  The pickup optical system 127 collects the excitation light BLc toward the phosphor layer 132, and includes, for example, a pickup lens 127a and a pickup lens 127b. Although not shown in FIG. 3, a first reflecting portion 132 a is provided in the optical path between the phase difference plate 126 and the phosphor layer 132. Note that details of the configuration of the first reflecting portion 132a will be described with reference to FIG.

  The first reflecting portion 132a reflects a part of the excitation light BLc1 of the excitation light BLc incident from the pickup optical system 27 toward the polarization separation element 150A, and the other of the excitation light BLc incident from the pickup optical system 27. Part of the excitation light BLc 2 is transmitted toward the phosphor layer 132. The first reflecting portion 132a transmits light in the second wavelength band.

  The fluorescent light emitting device 128 includes a phosphor layer 132 and a substrate (base material) 133 that supports the phosphor layer 132. In the fluorescent light emitting device 128, the phosphor layer 132 is fixedly supported on the substrate 133 in a state where the surface of the phosphor layer 132 opposite to the side on which the excitation light BLc2 is incident is in contact with the substrate 133.

  The phosphor layer 132 includes a phosphor that is excited by absorbing excitation light BLc2, which is excitation light that is light in the first wavelength band, and the phosphor excited by the excitation light BLc2 has a first wavelength. For example, fluorescent light (yellow light) having a peak wavelength in a wavelength region of 500 to 700 nm is generated as light in a second wavelength band different from the band.

  It is preferable to use a material having excellent heat resistance and surface processability for the phosphor layer 132. When the phosphor layer 132 is not rotated as in the present embodiment, the cooling effect due to the rotation of the phosphor layer 132 cannot be expected. Therefore, it is necessary to use the phosphor layer 132 that has high heat resistance and is easy to cool. For example, as the phosphor layer 132, 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 preferably used. it can.

  On the other hand, since these phosphor layers 132 have a small refractive index difference, backscattering of the excitation light BLc cannot be expected. Therefore, the first reflecting portion 132 a that reflects a part of the excitation light BLc is provided on the optical path between the phosphor layer 132 and the retardation plate 126.

  In addition, a method of using the light that has been transmitted through the phosphor layer 132 and then reflected and returned by a second reflecting portion 132b described later as illumination light WL is also conceivable. The polarization state is disturbed. Since the light whose polarization state is disturbed by the phosphor layer 132 includes a component that cannot be transmitted through the polarization separation element 150A, the utilization efficiency as the illumination light WL is reduced.

  In the present embodiment, as shown in FIGS. 4A, 4 </ b> B, and 4 </ b> C, the first reflecting portion 132 a is an optical path between the phase difference plate 126 and the phosphor layer 132. It is provided inside.

  The first reflecting portion 132a is composed of a diffuse reflection surface provided on the surface of the phosphor layer 132 on the side on which the excitation light BLc2 is incident. This diffuse reflection surface has a function of diffusing and reflecting a part of the excitation light BLc1 of the excitation light BLc toward the polarization separation element 150A.

  Specifically, for example, as shown in FIG. 4A, this diffuse reflection surface can be formed by applying texture processing to the surface of the phosphor layer 132 on which the excitation light BLc2 is incident. In this case, the first reflecting portion 132a can diffusely reflect a part of the excitation light BLc1 of the excitation light BLc toward the polarization separation element 150A using backscattering by the roughened surface. .

  Further, for example, as shown in FIG. 4B, the diffuse reflection surface can be formed by performing dimple processing on the surface of the phosphor layer 132 on which the excitation light BLc2 is incident. In this case, the first reflecting portion 132a may diffusely reflect a part of the excitation light BLc1 of the excitation light BLc toward the polarization separation element 150A using Fresnel reflection by the surface on which many convex surfaces are formed. it can.

  Further, the diffuse reflection surface is not limited to a surface having a large number of convex surfaces formed by dimple processing, for example, as shown in FIG. 4C, a surface having a large number of concave surfaces formed by dimple processing, or a convex surface and a concave surface by dimple processing. (Not shown) may have a large number (uneven surface).

  Further, a surface of the first reflecting portion 132a on the side on which the excitation light BLc is incident may be provided with a reflection enhancing film (not shown). In this case, the ratio of the excitation light BLc1 reflected by the first reflecting portion 132a can be increased.

In the present embodiment, as shown in FIGS. 4A, 4B, and 4C, the second reflection is performed on the opposite side of the phosphor layer 132 from the side on which the excitation light BLc is incident. A portion 132b is provided.
The second reflecting portion 132b is made of a specular reflecting surface. This specular reflection surface has a function of reflecting a part of the fluorescent light YL1 in the fluorescent light generated by the phosphor layer 132.

  Specifically, this specular reflection surface can be formed by providing the reflection film 132c on the surface of the phosphor layer 132 opposite to the side on which the excitation light BLc2 is incident.

  In addition, when the substrate 133 has light reflection characteristics, the mirror reflection surface can be formed by omitting the reflection film 132c and mirroring the surface of the substrate 133 that faces the phosphor layer 132.

  In the fluorescent light emitting device 128, as shown in FIG. 3, the phosphor layer 132 is fixed to the substrate 133 by an inorganic adhesive S having a light reflection characteristic provided on the side surface of the phosphor layer 132. In this case, the light leaking from the side surface of the phosphor layer 132 can be reflected into the phosphor layer 132 by the inorganic adhesive S having light reflection characteristics. Thereby, the light extraction efficiency of the fluorescent light generated by the phosphor layer 132 can be increased.

  A heat sink 134 is disposed on the surface of the substrate 133 opposite to the surface that supports the phosphor layer 132. Since the fluorescent light emitting element 128 can dissipate heat through the heat sink 134, the phosphor layer 132 can be prevented from being thermally deteriorated.

  Of the fluorescent light generated by the phosphor layer 132, a part of the fluorescent light YL 1 is reflected by the second reflecting portion 132 b and emitted to the outside of the phosphor layer 132. Of the fluorescent light generated by the phosphor layer 132, another part of the fluorescent light YL2 is emitted outside the phosphor layer 132 without passing through the second reflecting portion 132b. In this way, fluorescent light (yellow light) YL is emitted from the phosphor layer 132 toward the polarization separation element 150A. The fluorescent light (yellow light) YL includes red light and green light.

  The light (blue light) BLc1 reflected by the first reflecting portion 132a passes through the pickup optical system 27 and the phase difference plate 126 again. The excitation light BLc1 is converted from circularly polarized light to P-polarized light (linearly polarized light) by passing through the retardation plate 126. The excitation light BLp passes through the polarization separation element 150A.

  Fluorescent light (yellow light) YL emitted from the phosphor layer 132 toward the polarization separation element 150A passes through the pickup optical system 27 and the phase difference plate 126. At this time, since the fluorescent light YL is a light beam whose polarization direction is not aligned, even after passing through the phase difference plate 126, the fluorescence light YL enters the polarization separation element 150A with the polarization direction not aligned. The fluorescent light YL passes through the polarization separation element 150A.

  The illumination light (white light) WL is obtained by mixing the blue excitation light BLp and the fluorescent light (yellow light) YL that are transmitted through the polarization beam splitting element 150A. The illumination light WL passes through the polarization separation element 150A and then enters the integrator optical system 29. In order to obtain white light (illumination light) WL having a high color temperature, the reflectance of the first reflecting portion 132a with respect to the excitation light BLc1 is preferably 10 to 25%, and is preferably 15 to 20%. Is more preferable.

  The integrator optical system 129 makes the luminance distribution (illuminance distribution) uniform, and includes a pair of lens arrays 129a and 129b. The pair of lens arrays 129a and 129b includes a plurality of lenses arranged in an array. Then, the illumination light WL whose luminance distribution is made uniform by passing through the integrator optical system 129 is incident on the polarization conversion element 130.

  The polarization conversion element 130 aligns the polarization direction of the illumination light WL, and is composed of, for example, a combination of a polarization separation film and a retardation plate. In particular, the polarization conversion element 130 matches the polarization direction of the fluorescent light YL whose polarization direction is not aligned with the polarization direction (P-polarized light) of the excitation light BLp, so that one polarization component is changed to the other polarization component (for example, S Convert the polarization component to a P polarization component). Then, the illumination light WL whose polarization direction is aligned by passing through the polarization conversion element 130 enters the superimposing optical system 131.

  The superimposing optical system 131 is composed of a superimposing lens, and the illumination light WL is superimposed by passing through the superimposing optical system 131, so that the luminance distribution is made uniform and the axial symmetry around the light axis is enhanced.

  The light source device 10 having the above configuration obtains illumination light (white light) WL in which excitation light BLp and fluorescent light (yellow light) YL emitted from the phosphor layer 132 (fluorescent light emitting element 128) are mixed. be able to. That is, the excitation light BLp is the first color light in the present invention, the red light included in the fluorescent light (yellow light) YL is the second color light in the present invention, and the green light included in the fluorescent light (yellow light) YL. Light is the third color light in the present invention. The light source device 10 is configured such that the illumination light WL includes an S-polarized component and a P-polarized component for the polarization separation film 21 described later.

  As described above, the light source device 10 according to the present embodiment generates illumination light (white light) WL in which excitation light BLp composed of laser light that is coherence light and fluorescent light (yellow light) YL that is non-coherence light are mixed. Eject. Hereinafter, the excitation light BLp may be referred to as laser light BLp.

  Returning to FIG. 2, the collimator optical system 11 converts light emitted from the light source device 10 into parallel light, and includes, for example, two collimator lenses 11 a and a collimator lens 11 b. The number of lenses constituting the collimator optical system 11 may be one or a plurality.

  Note that the parallel light here does not mean light in which the light beam is completely collimated, but light adjusted so that the light beam becomes substantially parallel by passing through the collimator optical system 11. Means that. Therefore, the case where a part of the light beam that has passed through the collimator optical system 11 is not parallel to the optical axis ax1 is included.

  In the present embodiment, the light beam shaping device 12 includes a lens integrator unit 12A and a polarization beam splitter (polarization conversion element) 12B.

  The lens integrator unit 12A includes a first lens array 12A1 and a second lens array 12A2. The first lens array 12A1 is configured, for example, by arranging a plurality of lenses in a planar manner. The first lens array 12A1 divides a substantially parallel single light beam from the collimator optical system 11 into a plurality of small light beams by each lens and condenses each of them.

The second lens array 12A2 includes, for example, a plurality of lenses arranged in a plane corresponding to each lens of the first lens array 12A1. In the present embodiment, each lens of the second lens array 12A2 has an optical axis that is decentered in the X direction with respect to each lens of the first lens array 12A1, as shown in FIG. On the other hand, as shown in FIG. 2A, the optical axes of the lenses of the second lens array 12A2 are not decentered (match) with respect to the lenses of the first lens array 12A1 in the Y direction. .
Therefore, the light beam emitted from the collimator optical system 11 is compressed in the X direction by the lens integrator unit 12A. In the present embodiment, the light beam emitted from the collimator optical system 11 is compressed in half in the X direction.

  The polarization beam splitter 12B includes a light incident surface SA, a light exit surface SB, a polarization separation film 21, a reflection film 22, and a phase difference plate 23. The light exit surface SB includes a lower light exit surface SB1 and an upper light exit surface SB2. The lower light exit surface SB1 and the upper light exit surface SB2 are sequentially arranged along the + Y direction. The light incident surface SA is disposed at a position overlapping the lower light exit surface SB1 when viewed from the Z direction parallel to the optical axis ax1. Further, the phase difference plate 23 is provided on the lower light exit surface SB1.

  The polarization separation film 21 is disposed to face the light incident surface SA so as to form an angle of about 45 ° with respect to the light incident surface SA. The polarization separation film 21 has a function of separating a plurality of light beams L transmitted through the light incident surface SA based on polarization components.

  The polarization separation film 21 reflects the light beam Ls of the S polarization component out of the light beam L transmitted through the light incident surface SA. On the other hand, the polarization separation film 21 transmits the light beam Lp of the P-polarized component out of the light beam L transmitted through the light incident surface SA. The light that has passed through the polarization separation film 21 (the light beam Lp of the P-polarized component) is incident on the phase difference plate 23 disposed on the lower light exit surface SB1.

  The phase difference plate 23 is composed of a λ / 2 plate. The phase difference plate 23 converts the P-polarized component light beam Lp transmitted through the polarization separation film 21 into an S-polarized component light beam Ls.

  The reflection film 22 is disposed so as to face the upper light exit surface SB2 so that the surface thereof is parallel to the polarization separation film 21. The reflection film 22 reflects the S-polarized light beam Ls of the light beam L reflected by the polarization separation film 21 toward the upper light exit surface SB2.

On the upper light exit surface SB2 on which the phase difference plate 23 is not disposed, the light beam Ls of the S-polarized component reflected by the reflective film 22 is not converted in polarization direction and remains as S-polarized light.
In this way, the light incident on the light incident surface SA of the polarization beam splitter 12B is emitted as an S-polarized light beam Ls from the lower light exit surface SB1 and the upper light exit surface SB2. Therefore, the light from the lens integrator unit 12A is doubled in the Y direction by passing through the polarization beam splitter 12B.

  As described above, the light beam shaping device 12 compresses the light from the light source unit 100 to 1/2 in the X direction by the lens integrator unit 12A, and doubles it in the Y direction by the polarization beam splitter 12B. The light beam shaping device 12 shapes the light from the light source unit 100 so that the aspect ratio (ratio of the length in the Y direction to the length in the X direction) is 1: 4. That is, the light beam shaping device 12 shapes the cross-sectional shape of the light from the light source unit 100 so as to be substantially similar to the shape of the light shielding member 13 (sub pixel shape) described later.

  In the present embodiment, a light shielding member 13 is provided on the light exit surface SB of the polarization beam splitter 12B. The light shielding member 13 regulates at least one width of the light from the light beam shaping device 12 by shielding a part of the light from the light beam shaping device 12. 2A and 2B, the light shielding member 13 and the light exit surface SB are separated from each other in order to make the drawings easier to see.

  The superimposing optical system 14 is composed of, for example, a convex lens, and is for superimposing and entering the light that has passed through the light shielding member 13 to the light modulation device 200.

  The color separation element 15 includes a dichroic mirror (second reflective element) 15R, a dichroic mirror (third reflective element) 15G, and a dichroic mirror (first reflective element) 15B (hereinafter, dichroic mirrors 15R, 15G, and 15B). In some cases). These dichroic mirrors 15R, 15G, and 15B are arranged so as to form a minute angle with each other, and reflect the light that has passed through the light shielding member 13 at an angle of about 90 ° to generate R light (red light), G light ( It has a function of color separation into three color lights of green light) and B light (blue light). The dichroic mirrors 15R, 15G, and 15B allow R, G, and B colors to enter the microlens array 16 at different angles.

  In the present embodiment, the illumination light (white light) WL in which the fluorescent light YL that is non-coherence light and the laser light BLp are mixed is first incident on the dichroic mirror 15R, whereby red light (second light) that is non-coherence light. Color light) is separated and reflected toward the microlens array 16. Subsequently, the illumination light transmitted through the dichroic mirror 15R (light mixed with laser light BLp and green light) is incident on the dichroic mirror 15G so that only green light (third color light) that is non-coherent light is separated. And reflected toward the microlens array 16. The laser beam BLp that has passed through the dichroic mirror 15G is reflected toward the microlens array 16 by the dichroic mirror 15B.

  Returning to FIG. 2, the microlens array 16 is provided on the light incident side of the light modulation device 200. The microlens array 16 has a plurality of microlenses 16 a and forms a plurality of minute light beams from the light incident on the microlens array 16. Specifically, the R light incident on the microlens array 16 is divided into a plurality of minute light beams Rr by the plurality of microlenses 16a. Similarly, each of the G light and the B light is divided into a plurality of minute light beams Gg and a plurality of minute light beams Bb by the plurality of microlenses 16a. Each microlens 16a is disposed so as to correspond to each pixel 201 of the light modulation device 200 described later (see FIG. 8). Thereby, the minute light beams Rr, Gg, and Bb are incident on the sub-pixels 201R, 201G, and 201B, respectively.

  By the way, in the light source device 10 according to the present embodiment, since the light WL in which the laser light that is coherence light and the fluorescent light that is non-coherence light is mixed is emitted as described above, a speckle pattern is generated by the laser light. As a result, the image quality is degraded. Therefore, in the present embodiment, image quality is improved by taking speckle countermeasures only on the laser beam.

  Specifically, in the present embodiment, a configuration is employed in which the optical path of the laser beam BLp reflected by the dichroic mirror 15B toward the light modulation device 200 is temporally changed. That is, in this embodiment, the dichroic mirror 15B is composed of a deformable mirror.

  FIG. 5A is a cross-sectional view showing the configuration of the main part of the dichroic mirror 15B, and FIG. 5B is a diagram for explaining the operation of the dichroic mirror 15B. As shown in FIG. 5A, the dichroic mirror 15B includes a mirror member 40 and at least one piezoelectric element 41. The mirror member 40 has a reflection surface 40a that totally reflects the laser beam BLp on one surface. The piezoelectric element 41 is composed of, for example, a piezo element, and is attached to the side end surface of the mirror member 40. As shown in FIG. 5B, the piezoelectric element 41 changes the surface shape of the reflecting surface 40a by vibrating the mirror member 40, for example, to generate an uneven shape. The surface shape of the reflecting surface 40a changes with time as the piezoelectric element 41 vibrates. That is, when attention is paid to a certain point on the reflection surface 40 a, this point is temporally displaced with respect to the thickness direction of the mirror member 40.

FIG. 6 is a diagram for explaining the operation of the dichroic mirror 15B.
As shown in FIG. 6, the laser beam BLp is incident on the reflecting surface 40a of the dichroic mirror 15B. At this time, the laser beam BLp is reflected by the uneven shape generated on the reflection surface 40a by vibration. As described above, in the present embodiment, the optical path of the laser beam BLp reflected by the dichroic mirror 15B is changed temporally by changing the surface shape of the reflecting surface 40a. As a result, different speckle patterns are temporally superimposed on the image light that is enlarged and projected onto the screen SCR via the light modulation device 200. Therefore, according to the light source unit 100 according to the present embodiment, speckle due to the laser beam BLp can be reduced.

  When the dichroic mirror 15B is provided upstream of the dichroic mirror 15R and the dichroic mirror 15G, the non-coherent light transmitted through the dichroic mirror 15B is somewhat scattered by the uneven shape generated on the reflecting surface 40a. Therefore, there is a possibility that the utilization efficiency of the non-coherence light is lowered. However, in this embodiment, the dichroic mirror 15B is provided downstream of the dichroic mirror 15R and the dichroic mirror 15G. Therefore, the non-coherence light is reflected toward the microlens array 16 without being incident on the dichroic mirror 15B. Accordingly, loss due to non-coherence light passing through the dichroic mirror 15B is prevented. Therefore, in this embodiment, the illumination light emitted from the light source device 10 can be used efficiently.

  In the present embodiment, the case where only one piezoelectric element 41 is provided for the mirror member 40 has been described as an example. However, the present invention is not limited to this, and a plurality of piezoelectric elements 41 may be arranged. For example, when the rectangular reflecting surface 40a is viewed in plan, the piezoelectric elements 41 are preferably arranged so as to form a pair in the long side direction and the short side direction of the mirror member 40 as shown in FIG. The piezoelectric element 41 arranged in this way can generate vibrations two-dimensionally with respect to the mirror member 40, and can change the reflecting surface 40a into a surface shape in which unevenness is distributed two-dimensionally. . According to this, since the speckle pattern can be varied more favorably in time, it is possible to efficiently reduce the speckle due to the laser beam BLp.

  Next, the pixel structure of the light modulation device 200 will be described in detail. FIG. 8 is a diagram illustrating a pixel structure of the light modulation device 200, FIG. 8A is a diagram illustrating a planar configuration of the light modulation device 200, and FIG. 8B is a diagram illustrating a structure of one pixel. It is.

  As illustrated in FIG. 8A, the light modulation device 200 includes a plurality of pixels 201. Each pixel 201 includes a plurality of sub-pixels 201R, 201G, and 201B (hereinafter sometimes simply referred to as sub-pixels 201R, 201G, and 201B). The sub-pixel 201R corresponds to R light. That is, the minute light beam Rr is incident on the sub-pixel 201R. The sub-pixel 201G corresponds to G light, and a minute light beam Gg is incident thereon. The sub-pixel 201B corresponds to the B light, and the minute light beam Bb is incident thereon.

  In the light modulation device 200, the plurality of pixels 201 are arranged so that the sub-pixels 201R, 201G, and 201B are arranged in this order in the first direction (the left-right direction in FIG. 8A). The plurality of pixels 201 are arranged so that sub-pixels of the same color are arranged in a second direction (vertical direction in FIG. 8A) orthogonal to the first direction.

  Each of the sub-pixels 201R, 201G, and 201B is partitioned by a black matrix BM. In the present embodiment, the sub-pixels 201R, 201G, and 201B and the light exit surface SB in the polarization beam splitter 12B on which the light blocking member 13 is disposed have an optically conjugate relationship.

In the pixel 201, the sub-pixels 201R, 201G, and 201B are formed with a pitch of 12 μm, for example. Further, as shown in FIG. 8B, each of the sub-pixels 201R, 201G, and 201B having a rectangular shape is defined by a ratio of the length L1 in the short side direction and the length L2 in the long side direction, for example. The aspect ratio is set to about 1: 4 to 1: 3. In the present embodiment, the aspect ratio is set to 1: 4, for example.
In the present embodiment, the pixel 201 has a substantially square shape as a whole by including sub-pixels 201R, 201G, and 201 corresponding to three colors having an aspect ratio of 1: 4. Therefore, each pixel 201 has a uniform luminance, so that the light modulation device 200 can generate high-quality image light without unevenness.

  By the way, in order to generate good image light in the light modulation device 200, it is important that light of a corresponding color is appropriately incident on each of the sub-pixels 201R, 201G, and 201B. Therefore, it is necessary to accurately shape the light from the light source unit 100 by the light beam shaping device 12.

  As in the prior art, it is very difficult to shape the light from the light source unit 100 into a shape that perfectly matches the sub-pixels using only the light beam shaping device 12. FIG. 9A is a diagram illustrating a relationship between a minute light beam and a sub-pixel according to the related art. As shown in FIG. 9A, the cross-sectional shapes of the minute light beams Rr0, Gg0, and Bb0 are larger than the shapes of the sub-pixels 201R, 201G, and 201B. In this case, for example, the minute light beam Gg0 straddles the region between the sub-pixels adjacent to each other in one pixel. Therefore, the minute light beam Gg0 is incident not only on the sub-pixel 201G but also on the sub-pixel 201R and the sub-pixel 201B adjacent to the sub-pixel 201G. As a result, the image light is blurred and the quality of the image light projected on the screen SCR is deteriorated.

  On the other hand, in the projector 1 according to the present embodiment, part of the light shaped by the light beam shaping device 12 is shielded by the light shielding member 13 provided on the light exit surface SB of the polarization beam splitter 12B (see FIG. 2 (a) and (b)).

  FIG. 10 is a plan view showing a schematic configuration of the light shielding member 13. As shown in FIG. 10, the light shielding member 13 according to the present embodiment has an opening 13a having a width in the X direction that is smaller than the light exit surface SB of the polarization beam splitter 12B, for example. The light shielding member 13 is composed of a light shielding member configured by printing carbon black or the like, for example. In the light shielding member 13, the opening 13 a has a similar shape to each of the sub-pixels 201 R, 201 G, and 201 B of the light modulation device 200.

The light shielding member 13 regulates part of the light emitted from the light beam shaping device 12 so that the shape of the light that has passed through the light shielding member 13 corresponds to the shape of each of the subpixels 201R, 201G, and 201B. More specifically, the light shielding member 13 regulates the width of the light emitted from the light beam shaping device 12 by shielding a part of the light emitted from the light beam shaping device 12.
According to this, as shown in FIG. 9B, each minute light beam does not straddle the region between the sub-pixels 201R, 201G, and 201B adjacent to each other in each pixel 201. That is, for example, the minute light beam Gg is incident on the sub-pixel 201G, but is not incident on any of the sub-pixel 201R and the sub-pixel 201B adjacent to the sub-pixel 201G.

  The opening 13a of the light shielding member 13 has a rectangular shape having a short side in the X direction shown in FIG. 10 and a long side in the Y direction shown in FIG. The aspect ratio defined by the ratio of the length in the short side direction to the length in the long side direction of the opening 13a is set to 1: 4, for example.

  In the present embodiment, the X direction of the opening 13a corresponds to the short side direction of the subpixels 201R, 201G, and 201B, and the Y direction of the opening 13a corresponds to the long side direction of the subpixels 201R, 201G, and 201B. In the present embodiment, the shape of the light shielding member 13 is similar to the shape of the sub-pixels 201R, 201G, and 201B.

In the present embodiment, the light beam shaping device 12 shapes the light so that the cross-sectional shape of the light from the light source unit 100 is substantially similar to the shape of the light shielding member 13. That is, the light beam shaping device 12 compresses the light from the light beam shaping device 12 so that the component shielded by the light shielding member 13 in the light from the light beam shaping device 12 is reduced.
As a result, the amount of light from the light source unit 100 that is regulated (light-shielded) by the light-shielding member 13 is reduced, so that the light can pass through the opening 13a of the light-shielding member 13 efficiently. Therefore, heat generation by the light shielding member 13 is suppressed. Moreover, the light from the light source unit 100 can be used efficiently.

Thus, according to this embodiment, the minute light beams Rr, Gg, and Bb can be reliably incident on the corresponding sub-pixels 201R, 201G, and 201B, respectively. Therefore, it is possible to prevent the occurrence of color mixture due to the same color light entering the adjacent sub-pixels 201R, 201G, and 201B while improving the utilization efficiency of the light from the light source unit 100. Therefore, the projector 1 can project high-quality image light with reduced blur on the screen SCR.
Even when illumination light in which laser light and fluorescence are mixed as described above is used, speckle noise due to coherence light is reduced by a simple configuration in which the reflecting surface 40a of the dichroic mirror 15B is deformed. And bright image light can be projected onto the screen SCR.

(Second Embodiment)
Next, the light source device according to the second embodiment will be described. The difference between the present embodiment and the first embodiment is the configuration of a dichroic prism that reflects laser light, and the other configurations are the same. Therefore, the same members as those in the first embodiment are denoted by the same reference numerals, and details thereof are omitted.

  FIG. 11 is a diagram illustrating a schematic configuration of a dichroic mirror according to the second embodiment. As shown in FIGS. 11A and 11B, the dichroic mirror 15B according to the present embodiment includes a driving device 42 instead of the piezoelectric element 41 of the first embodiment. The drive device 42 is composed of, for example, an actuator.

  The drive device 42 changes the relative distance between the reflection surface 40a and the light source device 10 by moving the mirror member 40 along the direction of the optical axis ax1. Thereby, the optical path length of the laser beam BLp between the light source device 10 and the reflecting surface 40a of the mirror member 40 changes with time. According to this, similarly to the first embodiment, different speckle patterns are temporally superimposed on image light that is enlarged and projected onto the screen SCR via the light modulation device 200. Therefore, according to the present embodiment, speckle due to the laser beam BLp can be reduced.

(Third embodiment)
Next, the light source device according to the third embodiment will be described. The difference between the present embodiment and the first embodiment is the configuration of a dichroic prism that reflects laser light, and the other configurations are the same. Therefore, the same members as those in the first embodiment are denoted by the same reference numerals, and details thereof are omitted.

FIG. 12 is a diagram illustrating a schematic configuration of a dichroic mirror according to the third embodiment. FIG. 13 is a diagram for explaining the operation of the dichroic mirror according to the present embodiment.
As shown in FIG. 12, the dichroic mirror 15B according to the present embodiment includes a driving device 43 instead of the piezoelectric element 41 of the first embodiment. The drive device 43 is composed of, for example, an actuator.

  The driving device 43 temporally changes the angle formed by the reflection surface 40a of the dichroic mirror 15B and the optical axis ax1 of the laser beam BLp incident on the dichroic mirror 15B. Thereby, in this embodiment, the irradiation area BA by the laser beam BLp reflected by the reflecting surface 40a of the mirror member 40 is movable with respect to the light modulation device 200.

  The driving device 43 rotates the mirror member 40 counterclockwise around the rotation axis RA so as to reduce the angle θ formed by the optical axis ax1 and the reflecting surface 40a in FIG. Thereby, as shown in FIG. 13A, the irradiation area BA by the laser beam BLp moves relative to the light modulation device 200 in the right direction in FIG. On the other hand, the driving device 43 rotates the mirror member 40 clockwise around the rotation axis RA so as to increase the angle θ formed by the optical axis ax1 and the reflecting surface 40a in FIG. Thereby, as shown in FIG. 13B, the irradiation area BA by the laser beam BLp moves relative to the light modulation device 200 in the left direction in the figure.

According to the present embodiment, by moving the irradiation area BA by the laser beam BLp relative to the light modulation device 200, different speckle patterns are generated in the image light that is enlarged and projected onto the screen SCR via the light modulation device 200. It will be superimposed in time.
Therefore, also in the light source unit 100 according to the present embodiment, speckles due to the laser beam BLp can be reduced as in the above embodiment.

  In the present embodiment, the case where the irradiation area BA by the laser beam BLp is moved in the left-right direction relative to the light modulation device 200 has been described as an example. However, the present invention is not limited to this. The driving device 43 may be driven so as to be relatively moved in the vertical direction.

  In addition, although one embodiment of the present invention has been illustrated and described, the present invention is not necessarily limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. It is.

  For example, the second embodiment and the third embodiment may be combined. That is, the drive device 42 or the drive device 43 changes the relative distance between the reflection surface 40a and the light source device 10 by moving the mirror member 40 along the optical axis ax1 direction as shown in FIG. As shown in FIG. 12, the angle formed by the reflecting surface 40a of the dichroic mirror 15B and the optical axis ax1 of the laser beam BLp incident on the dichroic mirror 15B may be changed with time.

  In the above-described embodiment, the case where white light including three colored lights is emitted from the light source device 10 is described as an example. However, the present invention is not limited to this, and any light including coherence light and non-coherence light may be used. It may emit light composed of only one color light. In this case, the color separation element 15 may have only two dichroic mirrors.

  Moreover, in the said embodiment, although the case where the light source unit 100 was provided with the semiconductor laser 121a and the fluorescence light emitting element 128 was mentioned as an example, this invention is not limited to this. It is sufficient that the light source unit 100 can emit coherent light and non-coherent light.

  In the above embodiment, the first reflecting element is provided downstream of the dichroic mirror 15R and the dichroic mirror 15G. In this case, however, the first reflecting element does not necessarily have to be a dichroic mirror, and is a total reflection mirror. But you can. However, when the first reflective element is provided upstream of the dichroic mirror 15R or the dichroic mirror 15G, the first reflective element must be a dichroic mirror.

DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Light source device (light source), 15 ... Color separation element (space separation means), 15R ... Dichroic mirror (2nd reflective element), 15G ... Dichroic mirror (3rd reflective element), 15B ... Dichroic Mirror (first reflection element), 42, 43... Driving device, 200... Light modulation device (light modulation element)

Claims (6)

Light source that emits the first color light and the second color light, spatial color separation means having the first reflection element and the second reflection element, and the light on which the first color light and the second color light are incident A projector including a modulation element;
The first color light is coherence light, and the second color light is non-coherence light;
The first reflective element reflects the first color light;
The second reflective element reflects the second color light;
The projector according to claim 1, wherein the first reflective element temporally changes an optical path of the first color light reflected by the first reflective element. The projector according to claim 1, wherein the first reflecting element is a deformable mirror. The projector according to claim 1, wherein the first reflective element includes a driving device that temporally changes an optical path length of the first color light between the light source and an incident surface of the first reflective element. The first reflective element includes a driving device that temporally changes an angle formed by an incident surface of the first reflective element and an optical axis of the first color light incident on the first reflective element. Item 14. The projector according to Item 1. The light source further emits third color light that is non-coherence light,
The spatial color separation means further includes a third reflective element that reflects the third color light,
The projector according to claim 1, wherein the first reflective element is provided downstream of the second reflective element and the third reflective element. The coherence light is laser light;
The projector according to claim 1, wherein the non-coherence light is fluorescence generated by excitation of the laser light.

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