JP5673119B2 - Light source device and projector - Google Patents

Description

  The present invention relates to a light source device and a projector.

  In recent years, as a light source device using a laser light source, there has been proposed a light source device that uses, as illumination light, fluorescence obtained by irradiating a phosphor instead of directly using laser light as illumination light (for example, Patent Document 1). reference).

  The light source device of Patent Document 1 includes a light source that emits excitation light (blue light) and two types of phosphor layers (a red phosphor layer and a green phosphor layer) on a disk that is rotated by a motor. And a fluorescent plate formed. On the disk, three segment regions are formed along the rotation direction. Two of the three segment areas are formed with two types of phosphor layers that emit different colored light (red light and green light), and the remaining segment areas scatter excitation light (blue light). A scatterer is formed.

  According to such a light source device, since the three colored lights are sequentially emitted in time division using the excitation light and the two types of phosphor layers, the light source capable of obtaining white light by time integration. It becomes a device.

  Further, in FIG. 6 of Patent Document 1, the excitation light that faces the emission surface of the phosphor layer and selectively reflects the excitation light transmitted through the phosphor layer without being wavelength-converted and re-directs it to the phosphor layer. A configuration including a light reflection layer has been proposed. According to such a configuration, since the excitation light that has not been wavelength-converted can be used again for light emission in the phosphor layer, the conversion efficiency (ratio of the amount of fluorescent light obtained to the amount of incident excitation light) is improved. To do.

JP 2009-277516 A

  In the light source device of the above patent document, the excitation light emitted from the phosphor layer is diffused light diffused by the phosphor. Therefore, the area of the region where the phosphor layer is irradiated by the excitation light reflected by the excitation light reflecting layer is larger than the area of the region where the phosphor layer is directly irradiated by the excitation light emitted from the excitation light source. Become. As a result, the emission area of the fluorescence increases, and the fluorescence etendue (Etendue: product of the cross-sectional area of the beam bundle and the solid solid angle emitted from the light source) increases.

  In a light source having a large etendue, when the emitted light propagates in the optical path, the loss component easily exceeds the swallowing angle of the optical system. Therefore, as a result, the effect of reusing the excitation light reflected by the excitation light reflecting layer is reduced.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to improve the utilization efficiency of excitation light and provide a light source device with a small etendue. It is another object of the present invention to provide a projector having such a light source device and capable of displaying a high-quality image.

In order to solve the above problems, a light source device according to the present invention includes a substrate, a phosphor layer provided on the substrate, a light source that emits light including first light that excites the phosphor, A wavelength selection mirror that transmits light corresponding to a wavelength band of fluorescence emitted from the phosphor layer and reflects light corresponding to a peak wavelength of transmitted light that has passed through the phosphor layer among the first light, and the wavelength selection A condensing optical system provided on an optical path of the transmitted light between a mirror and the phosphor layer, and the substrate is formed of a material that transmits at least light corresponding to the peak wavelength of the first light It is characterized by being.
According to this configuration, the excitation light that has passed through the phosphor layer can be reflected by the wavelength selection mirror and irradiated again to the phosphor layer to be converted into fluorescence, so that the use efficiency of the excitation light can be improved. . In addition, since the excitation light reflected by the wavelength selection mirror is irradiated after being condensed by the condensing optical system, the increase in the irradiation area of the excitation light can be reduced, and the increase in the fluorescence emission area is suppressed. can do. Therefore, a fluorescent light source with a small etendue can be obtained.

In the present invention, the substrate is formed of a material that transmits at least light corresponding to the peak wavelength of the first light, and the phosphor layer is a side on which the first light is incident on the substrate. It is desirable to be provided on the opposite surface.
The phosphor layer emits a lot of fluorescence on the side where the excitation light is incident, and generates heat due to the excitation light and fluorescence emission. However, according to this configuration, the heat generated in the phosphor layer can be efficiently dissipated through the substrate, preventing the temperature rise of the phosphor layer and suppressing the temperature quenching of the material forming the phosphor layer. can do.

In the present invention, it is preferable that the substrate is provided to be rotatable around a predetermined rotation axis, and the phosphor layer is provided in an annular region around the rotation axis on the substrate.
According to this configuration, since the excitation light does not continue to irradiate the same position on the phosphor layer, thermal degradation of the phosphor layer can be prevented and the life of the apparatus can be extended.

In the present invention, it is desirable to have a light guide optical system that splits the first light and the second light from the light emitted from the light source, and emits the fluorescence and the second light. .
According to this configuration, it is possible to form fluorescence and second light using light emitted from the same light source. Therefore, the device configuration of the light source can be simplified.

In the present invention, it is desirable to have a synthesis optical system that synthesizes the fluorescence and the second light.
According to this configuration, light having a wide wavelength band can be emitted from the same optical path.

In the present invention, it is preferable that the first light is a color light of a complementary color of the fluorescence.
According to this configuration, a light source device that emits white light can be obtained.

In the present invention, the phosphor layer overlaps the phosphor layer in plan view between the phosphor layer and the surface of the substrate on which the first light is incident, and corresponds to the peak wavelength of the first light. It is desirable to provide a wavelength selection film that transmits light and reflects light in the fluorescence wavelength band.
According to this configuration, the fluorescence generated in the phosphor layer is prevented from returning to the incident side of the excitation light, and can be effectively directed in the emission direction.

In the present invention, it is desirable that the light source emits light in a blue wavelength band as the first light.
According to this configuration, bright display is possible in a blue region in color display.

In the present invention, the light source is preferably a solid light source.
According to this configuration, the light source device can be downsized and the life of the light source can be extended.

In the present invention, the light source is preferably a semiconductor laser.
According to this configuration, high-output excitation light can be emitted.

According to another aspect of the invention, there is provided a projector comprising: the light source device described above; a light modulation element that modulates light emitted from the light source apparatus; and a projection optical system that projects light modulated by the light modulation element. It is characterized by.
According to this configuration, since the above-described light source device is provided, high-quality image display is possible.

It is a schematic diagram which shows the structure of the light source device of this embodiment. It is a graph which shows the light emission characteristic of a light source device and a fluorescent substance layer. It is a schematic diagram which shows the light emitting element with which the light source device of this embodiment is provided. It is a schematic diagram which shows the structure of the fluorescent substance layer with which a light emitting element is provided. It is a schematic diagram which shows the behavior of the excitation light which permeate | transmits a fluorescent substance layer. It is a schematic diagram which shows the structure of a light-diffusion member. It is a schematic diagram which shows the projector of this embodiment. It is explanatory drawing of a polarization conversion element.

  Hereinafter, a light source device and a projector according to an embodiment of the present invention will be described with reference to FIGS. In all the drawings below, the dimensions and ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.

  FIG. 1 is a schematic diagram illustrating a configuration of a light source device 100 according to the present embodiment. As shown in FIG. 1, a light source device 100 includes a light source unit (light source) 10, a collimating optical system 20, a light guiding optical system 30, a light emitting element 40, a pickup lens (condensing optical system) 50, a dichroic mirror (wavelength selection mirror). ) 60, a light diffusion member 70, and a synthetic optical system 80.

  In the light source device 100, yellow fluorescence is generated in the light emitting element 40 by irradiating the light emitting element 40 with a part of the laser beam B emitted from the light source unit 10 as the first light. The laser light is blue light and has a complementary color relationship with fluorescence. Further, the remaining part of the laser beam B enters the light diffusion member 70 as the second light and is diffused. The light source device 100 emits white light L by combining the fluorescence and the blue laser light that has been diffused through the light diffusion member 70.

  The light source device 100 of this embodiment can be suitably used as illumination light for a projector. Hereinafter, the configuration of the light source device 100 will be described in order.

  The light source unit 10 includes a plurality of (three in the drawing) laser light sources 11 and is a laser light source array that emits a blue (light emission intensity peak: about 445 nm, see FIG. 2A) laser light B. In the light source unit 10, for example, a semiconductor laser light source (solid light source) 11 can be two-dimensionally arranged to provide a high-output excitation light source. In FIG. 2A, reference numeral B denotes a color light (blue light) component emitted from the light source unit 10.

  The light source unit 10 may use only one laser light source instead of the laser light source array. It is also possible to use other solid light sources such as LEDs instead of laser light sources. Furthermore, a light source other than a solid light source that emits colored light having a peak wavelength other than 445 nm may be used as long as the light has a wavelength that can excite a fluorescent material to be described later.

  In the collimating optical system 20, a collimator lens array 21, a condenser lens 23, and a collimating lens 25 are arranged in this order on the optical path. The laser beam B emitted from the light source unit 10 is incident on a small lens of a collimator lens array 21 provided corresponding to the laser light source of the light source unit 10 as one body 1 and is collimated. By passing through the collimating lens 25 after being condensed, the beam bundle as a whole is reduced.

  The light guide optical system 30 includes a first mirror 31 and a second mirror 32. Among these, the first mirror 31 is a beam splitter that reflects a part of the incident laser beam B and transmits the remaining part. The second mirror 32 is a reflection mirror that reflects the laser beam B.

  The first mirror 31 has a configuration in which a light separation film such as a dielectric multilayer film is formed on a transparent substrate. The ratio of the reflected light and transmitted light of the first mirror 31 to be used can be arbitrarily controlled by controlling the configuration (refractive index, thickness, etc.) of the light separation film.

  The laser light B emitted from the collimating optical system 20 is incident on the first mirror 31, and part of the laser light B is transmitted and emitted as the first excitation light B1. The remaining part of the laser beam B reflected by the first mirror 31 is reflected by the second mirror 32 and enters the light emitting element 40 as the second excitation light B2. In this way, the laser beam B is divided into two beam bundles of the first excitation light B1 and the second excitation light B2. However, the first excitation light B <b> 1 is not light that excites the light diffusion member 70. The first excitation light B1 is diffused by the light diffusing member 70 and emitted from the light diffusing member 70 as blue light whose light distribution is changed. The second excitation light B2 is the first light in the present invention, and the first excitation light B1 is the second light in the present invention.

  The light emitting element 40 uses the phosphor layer 45 provided in the light emitting element 40 to convert the second excitation light B2 into fluorescence having a wavelength different from that of the second excitation light B2.

  The light emitting element 40 will be described with reference to FIGS. FIG. 3 is a plan view of the light emitting element 40, and FIG. 4 is a partial cross-sectional view of the phosphor layer 45 provided in the light emitting element 40.

  As shown in FIGS. 1 and 3, the light emitting element 40 includes a substrate 41 having a circular shape in plan view, and a phosphor layer 45 provided in an annular region AR set on the first main surface 41 a of the substrate 41. Have. The light emitting element 40 is rotatably provided with a rotation shaft 48 provided in parallel with the normal line of the first main surface 41 a passing through the center of the substrate 41 and connected to a motor 49. As shown in FIG. 3, the phosphor layer 45 is provided substantially concentrically with respect to the rotation center of the substrate 41 (that is, the intersection between the rotation shaft 48 and the substrate 41).

  In such a light emitting element 40, the second main surface 41b on which the phosphor layer 45 is not formed faces the light guide optical system 30 side, and the second excitation light B2 is incident from the second main surface 41b side. Has been placed.

  The phosphor layer 45 has phosphor particles that emit fluorescence, and absorbs the second excitation light B2 (blue light) to produce yellow fluorescence (peak of emission intensity: about 550 nm, see FIG. 2B). Has a function to convert. In FIG. 2B, the component indicated by R is a color light component that can be used as red light among the yellow light emitted from the phosphor layer 45, and the component indicated by G is also used as green light. Possible color light component. In FIG. 1, fluorescence including red light R and green light G is indicated by reference numeral RG. The configuration of the phosphor layer 45 will be described in detail later.

  Normally, the phosphor layer 45 emits a lot of fluorescence and generates heat on the side where the excitation light is incident. Therefore, when the phosphor layer 45 is irradiated with excitation light from the second main surface 41b side, the amount of heat generated on the phosphor layer 45 on the side close to the substrate 41 increases. However, at this time, the heat generated in the phosphor layer 45 is efficiently dissipated through the substrate 41, so that the temperature of the phosphor layer 45 is prevented from rising and the temperature quenching of the forming material of the phosphor layer 45 is suppressed. be able to.

  The substrate 41 includes a substrate body 42, a wavelength selection film 43 provided between the substrate body 42 and the phosphor layer 45, and an antireflection coating provided on the surface of the substrate body 42 opposite to the wavelength selection film 43. And a film 44.

  The substrate body 42 uses a material that transmits blue light, which is excitation light, as a forming material. For example, quartz glass, crystal, sapphire (single crystal corundum), transparent resin, or the like can be used. Among these, quartz glass, quartz, and sapphire, which are inorganic materials, are preferably used so as not to be deformed by heating with excitation light. Further, when the substrate 41 is made to dissipate heat generated when light is emitted from the phosphor layer 45, it is preferable to use quartz as a forming material in consideration of heat transfer and the like.

  The wavelength selection film 43 is a light separation film such as a dielectric multilayer film laminated on the surface of the substrate body 42. The wavelength selection film 43 has wavelength selectivity that selectively transmits color light in the wavelength band of the second excitation light B2 and reflects color light in other wavelength bands. Specifically, the wavelength selection film 43 transmits blue light (for example, light having a wavelength of about 445 nm) and reflects light having a longer wavelength than blue light (for example, light having a longer wavelength than 480 nm). As a result, the second excitation light B <b> 2 that is blue light is transmitted through the wavelength selection film 43 and is incident on the phosphor layer 45. Further, it is possible to prevent the fluorescence RG generated in the phosphor layer 45 from returning in the direction of the light guide optical system 30 and to direct it in the emission direction (the direction of the synthesis optical system 80).

  As the antireflection film 44, a film composed of a generally known dielectric multilayer film can be used. The plurality of layers constituting the antireflection film 44 are adjusted in refractive index so as to prevent reflection of the second excitation light B2. Thereby, the loss of the 2nd excitation light B2 in the 2nd main surface 41b can be suppressed.

  As shown in FIG. 4, the phosphor layer 45 includes a plurality of phosphor particles 451 that emit fluorescence, and a base material 452 having optical transparency. The second excitation light B2 is incident on the phosphor layer 45 and part thereof is converted into fluorescence RG. Further, the component of the second excitation light B2 that has not been converted into the fluorescence RG by the phosphor layer 45 is refracted and diffused by the phosphor particles 451 and emitted.

  The phosphor particles 451 are particulate fluorescent materials that absorb the second excitation light B2 and emit fluorescence RG. For example, the phosphor particles 451 include a substance that emits fluorescence when excited by blue light having a wavelength of about 445 nm, and a part of the second excitation light B2 is transferred from the red wavelength band to the green wavelength band. Converted into light containing As such phosphor particles 451, those having an average particle diameter of about 1 μm to several tens of μm are known to exhibit high luminous efficiency.

As the phosphor particles 451, a commonly known YAG (yttrium, aluminum, garnet) phosphor can be used. For example, a YAG phosphor having a composition represented by (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce having an average particle diameter of 10 μm (refractive index: about 1.8) can be used.

Note that the phosphor particles 451 may be formed of a single material, or a mixture of particles formed using two or more materials may be used as the phosphor particles 451. For example, a material such as a phosphor having a composition represented by (Sr, Ca) AlSiN ₃ : Eu that emits red fluorescence, and a phosphor having a composition represented by (YGd) ₃ Al ₅ O ₁₂ : Ce that emits green fluorescence. It is also possible to adjust phosphor particles from which fluorescent RG can be obtained by mixing and using such materials.

  Here, the average particle diameter of the phosphor particles 451 can be measured using a particle size distribution measuring apparatus (for example, SALD 2200 (manufactured by Shimadzu Corporation)) based on the laser diffraction scattering method. In this embodiment, the median particle size (Median Size: median of particle size distribution) is adopted as the average particle size.

  The base material 452 functions as a binder for the phosphor particles 451. As a material for forming the base material 452, a resin material having optical transparency can be used, and among them, a silicone resin having high heat resistance can be preferably used.

  The motor 49 rotates the light emitting element 40 at 7500 rpm, for example. In this case, the region (beam spot) irradiated with the second excitation light B2 in the light emitting element 40 moves in the circumferential direction. That is, the motor 49 functions as a position displacement unit that displaces the position of the beam spot in the light emitting element 40. Thereby, since excitation light does not continue irradiating the same position on the light emitting element 40, the thermal deterioration of an irradiation position can be prevented and a lifetime of an apparatus can be extended. Further, since the phosphor 45 is provided substantially concentrically with respect to the rotation center of the substrate 41, the locus drawn by the beam spot of the second excitation light B2 and the shape of the phosphor layer 45 can be matched. The phosphor layer 45 can be formed with a minimum width. Therefore, waste of material can be suppressed.

  The pickup lens 50 is provided on the optical path of the remaining portion of the second excitation light B2 (light transmitted through the phosphor layer 45) between the phosphor layer 45 and a dichroic mirror 60 described later. The fluorescence RG emitted from the phosphor layer 45 and the remaining portion of the second excitation light B2 that has not been converted into the fluorescence RG by the phosphor layer 45 are incident on the pickup lens 50 provided facing the phosphor layer 45. To do. The pickup lens 50 collimates the light emitted while diffusing from the phosphor layer 45.

  The light transmitted through the pickup lens 50 enters a dichroic mirror (wavelength selection mirror) 60. The dichroic mirror 60 has wavelength selectivity that selectively reflects color light in the wavelength band of the second excitation light B2 and transmits color light in other wavelength bands. Specifically, blue light (for example, light having a wavelength of about 445 nm) is reflected, and light having a longer wavelength than blue light (for example, light having a longer wavelength than 480 nm) is transmitted. The dichroic mirror 60 has a dielectric multilayer film.

  Therefore, in such a dichroic mirror 60, yellow fluorescence RG that is light having a wavelength longer than that of blue light is transmitted, and is emitted in the direction of the synthesis optical system 80 as fluorescence with high color purity. On the other hand, the second excitation light B <b> 2 that is blue light is reflected toward the phosphor layer 45.

  At this time, the second excitation light B2 traveling from the dichroic mirror 60 toward the phosphor layer 45 is condensed on the phosphor layer 45 by passing through the pickup lens 50 functioning as a condensing lens. Thereby, there exist the following effects.

  Here, the effect of the present invention will be described with reference to FIG. However, in FIG. 5, the emission region of the second excitation light B2 emitted from the first main surface 41a is approximated to a point. FIG. 5 is an explanatory diagram showing the behavior of the second excitation light B <b> 2 emitted from the phosphor layer 45. FIG. 5A shows the case where there is no pickup lens 50 as in the prior art, and FIG. 5B shows the case where there is a pickup lens 50 as in this embodiment.

  In the prior art, as shown in FIG. 5A, the second excitation light B2 emitted from the phosphor layer 45 is reflected by the dichroic mirror 60 while being diffused. Therefore, a part of the second excitation light B2 (indicated by reference sign B2a in the figure) is reflected and becomes stray light without going to the phosphor layer 45 and cannot be used for fluorescence emission.

  In addition, the component (indicated by symbol B2b in the figure) incident on the phosphor layer 45 forms an irradiation region wider than the emission region of the second excitation light B2. In FIG. 5A, the width of the irradiation region of the second excitation light B <b> 2 b reflected by the dichroic mirror 60 is indicated as W. Thus, the irradiation area by the 2nd excitation light B2 reflected by the dichroic mirror 60 becomes wider than the irradiation area by the 2nd excitation light B2 irradiated from the 1st main surface 41a side. That is, if an attempt is made to reuse the component of the second excitation light B2 that has transmitted through the phosphor layer 45 without contributing to the generation of fluorescence, the emission area of the fluorescence increases, and the etendue of the fluorescence increases. .

  On the other hand, according to the present invention, as shown in FIG. 5B, the second excitation light B <b> 2 from the phosphor layer 45 toward the dichroic mirror 60 is collimated by the pickup lens 50. The pickup lens 50 functions as a condensing lens for the second excitation light B <b> 2 reflected by the dichroic mirror 60 and traveling toward the phosphor layer 45. Therefore, the second excitation light B2 reflected by the dichroic mirror 60 is collected on the phosphor layer 45, and the irradiation area becomes narrower than that in FIG. Therefore, it is possible to suppress an increase in the fluorescence emission area due to the second excitation light B2 reflected by the dichroic mirror 60, and to keep the fluorescence etendue small.

  In this way, the second excitation light B2 emitted from the phosphor layer 45 is incident again on the phosphor layer 45 and effectively used for fluorescence emission.

FIG. 6 is a partial cross-sectional view illustrating the configuration of the light diffusing member 70.
First, as shown in FIG. 6A, the light diffusing member 70A employs a configuration in which a filler 701 having a high refractive property such as TiO ₂ is dispersed in a base material 702 having a light transmission property. be able to. As the base material 702, a resin material similar to that of the above-described base material 452 can be used. Such a light diffusing member 70A can be formed by applying and curing a precursor of a base material 702 in which a filler 701 is dispersed.

  As shown in FIG. 6A, in such a light diffusing member 70A, the first excitation light B1 enters the light diffusing member 70A and is refracted and scattered by the filler 701, so that the light distribution is changed. Emitted as blue diffused light.

  In addition, as shown in FIG. 6B, the light diffusing member 70 </ b> B can employ a configuration in which a plurality of projections and depressions are provided on the surface of a light-transmitting base material 703. In FIG. 6B, a plurality of recesses 704 are provided on the surface of the base material 703. Such a light diffusing member 70B is obtained by applying the precursor of the base material 703, curing the base material 703 in a state of being embossed using a convex mold corresponding to the concave portion 704, and removing the convex mold after curing. Can be formed.

  As shown in FIG. 6B, in such a light diffusing member 70 </ b> B, the first excitation light B <b> 1 enters the light diffusing member 70 and is refracted / scattered by the recess 704, thereby changing the light distribution. Emitted as blue diffused light.

  Further, when the light source device 100 according to the present embodiment is employed as a light source of a projector, the first excitation light B1 is laser light, and thus speckle noise is generated in an image formed by the first excitation light B1. However, speckle noise can be reduced if the position where the first excitation light B1 is incident on the light diffusing member 70 is changed with time, for example, by rotating the light diffusing member 70 around a predetermined rotation axis. Can do.

  The combining optical system 80 includes a first combining mirror 81 and a second combining mirror 82. Among these, the 1st synthetic | combination mirror 81 is a reflective mirror which reflects light. The second synthesis mirror 82 is a dichroic mirror that transmits blue light (for example, light having a wavelength of about 445 nm) and reflects light having a longer wavelength than blue light (for example, light having a longer wavelength than 480 nm). is there. The second composite mirror 82 has a configuration in which a light separation film such as a dielectric multilayer film is formed on a transparent substrate.

  The fluorescence RG emitted from the light emitting element 40 is reflected by the first synthesis mirror 81, reflected by the second synthesis mirror 82, and emitted outside. Further, the first excitation light B <b> 1 emitted from the light scattering member 70 passes through the pickup lens 51 provided to face the light emission surface of the light scattering member 70 and is collimated, and then the second synthesis mirror 82. And is ejected to the outside.

In this way, the fluorescence RG and the first excitation light B1 are synthesized and mixed on the optical path, and emitted as light in a wide wavelength band of yellow and blue (that is, white light L).
The light source device 100 of this embodiment functions as described above.

  FIG. 7 is a schematic diagram showing the projector PJ of this embodiment. As shown in the figure, the projector PJ includes a light source device 100, a color separation optical system 200, a liquid crystal light valve (light modulation element) 400R, a liquid crystal light valve 400G, a liquid crystal light valve 400B, a color composition element 500, and a projection optical system 600. It is out.

The projector PJ generally operates as follows. The light emitted from the light source device 100 is separated into a plurality of color lights by the color separation optical system 200. The plurality of color lights separated by the color separation optical system 200 are incident on the corresponding liquid crystal light valve 400R, liquid crystal light valve 400G, and liquid crystal light valve 400B and modulated. A plurality of color lights modulated by the liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B are incident on the color synthesis element 500 and synthesized. The light synthesized by the color synthesizing element 500 is enlarged and projected by a projection optical system 600 onto a screen SCR such as a wall or a screen, and a full-color projection image is displayed.
Hereinafter, each component of the projector PJ will be described.

  The collimating optical system 110 includes a first lens 112 that suppresses the spread of light emitted from the light source device 100 and a second lens 114 that substantially collimates light incident from the first lens 112, and as a whole, the light source device. The light emitted from 100 is collimated. In the present embodiment, the first lens 112 and the second lens 114 are configured as convex lenses.

  The lens array 120 and the lens array 130 make the luminance distribution of the light emitted from the collimating optical system 110 uniform. The lens array 120 includes a plurality of first small lenses 122, and the lens array 130 includes a plurality of second small lenses 132. The first small lens 122 has a one-to-one correspondence with the second small lens 132. Light emitted from the collimating optical system 110 is spatially divided and incident on the plurality of first small lenses 122. The first small lens 122 causes the incident light to form an image on the corresponding second small lens 132. Thereby, a secondary light source image is formed on each of the plurality of second small lenses 132. Note that the outer shapes of the first small lens 122 and the second small lens 132 are substantially similar to the outer shapes of the image forming regions of the liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B.

  The polarization conversion element 140 aligns the polarization state of the light L emitted from the lens array 120 and the lens array 130. As shown in FIG. 8, the polarization conversion element 140 includes a plurality of polarization conversion cells 141. The polarization conversion cell 141 has a one-to-one correspondence with the second small lens 132. The light L from the secondary light source image formed on the second small lens 132 enters the incident region 142 of the polarization conversion cell 141 corresponding to the second small lens 132.

  Each polarization conversion cell 141 is provided with a polarization beam splitter film 143 (hereinafter referred to as a PBS film 143) and a phase difference plate 145 corresponding to the incident region 142. The light L incident on the incident region 142 is separated by the PBS film 143 into P-polarized light L1 and S-polarized light L2 with respect to the PBS film 143. One of the P-polarized light L1 and the S-polarized light L2 (here, S-polarized light L2) is reflected by the reflecting member 144 and then enters the phase difference plate 145. The S-polarized light L2 incident on the phase difference plate 145 is converted into the polarization state of the other polarization (here, P-polarized light L1) by the phase difference plate 145 to become the P-polarized light L3, and is emitted together with the P-polarized light L1. .

  The superimposing lens 150 superimposes the light emitted from the polarization conversion element 140 in the illuminated area. The light emitted from the light source device 100 is spatially divided and then superimposed, whereby the luminance distribution is made uniform and the axial symmetry around the light axis 100ax is enhanced.

  The color separation optical system 200 includes a dichroic mirror 210, a dichroic mirror 220, a mirror 230, a mirror 240, a mirror 250, a field lens 300R, a field lens 300G, a field lens 300B, a relay lens 260, and a relay lens 270. The dichroic mirror 210 and the dichroic mirror 220 are obtained by, for example, laminating a dielectric multilayer film on a glass surface. The dichroic mirror 210 and the dichroic mirror 220 have a characteristic of selectively reflecting color light in a predetermined wavelength band and transmitting color light in other wavelength bands. Here, the dichroic mirror 210 reflects green light and blue light, and the dichroic mirror 220 reflects green light.

  The light L emitted from the light source device 100 enters the dichroic mirror 210. The red light R of the light L enters the mirror 230 through the dichroic mirror 210, is reflected by the mirror 230, and enters the field lens 300R. The red light R is collimated by the field lens 300R and then enters the liquid crystal light valve 400R.

  Green light G and blue light B in the light L are reflected by the dichroic mirror 210 and enter the dichroic mirror 220. The green light G is reflected by the dichroic mirror 220 and enters the field lens 300G. The green light G is collimated by the field lens 300G and then enters the liquid crystal light valve 400G.

  The blue light B that has passed through the dichroic mirror 220 passes through the relay lens 260 and is reflected by the mirror 240, then passes through the relay lens 270, is reflected by the mirror 250, and enters the field lens 300B. The blue light B is collimated by the field lens 300B and then enters the liquid crystal light valve 400B.

  The liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B are configured by a light modulation device such as a transmissive liquid crystal light valve. The liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B are electrically connected to a signal source (not shown) such as a PC that supplies an image signal including image information. The liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B modulate the incident light for each pixel based on the supplied image signal to form an image. The liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B form a red image, a green image, and a blue image, respectively. The light (formed image) modulated by the liquid crystal light valve 400R, the liquid crystal light valve 400G, and the liquid crystal light valve 400B enters the color composition element 500.

The color composition element 500 is configured by a dichroic prism or the like. The dichroic prism has a structure in which four triangular prisms are bonded to each other. The surface to be bonded in the triangular prism becomes the inner surface of the dichroic prism. On the inner surface of the dichroic prism, a mirror surface that reflects red light and transmits green light and a mirror surface that reflects blue light and transmits green light are formed orthogonal to each other. The green light incident on the dichroic prism is emitted as it is through the mirror surface. The red light and blue light incident on the dichroic prism are selectively reflected or transmitted by the mirror surface and emitted in the same direction as the emission direction of the green light. In this way, the three color lights (images) are superimposed and combined, and the combined color light is enlarged and projected onto the screen SCR by the projection optical system 600.
The projector PJ of this embodiment has the above configuration.

  According to the light source device 100 configured as described above, the use efficiency of excitation light can be improved, and the light source device performance with a small etendue can be achieved.

  Further, according to the projector PJ having the above-described configuration, high-quality image display is possible.

  In the present embodiment, the wavelength selection film 43 is provided on the entire surface of the substrate body 42. However, if the wavelength selection film 43 is provided so as to overlap the annular area AR on which the phosphor layer 45 is provided, the other areas are provided. Is not necessary.

  Further, in the present embodiment, the fluorescent light is emitted from the fluorescent material layer 45, and the light source device 100 emits white light as a whole. However, the present invention is not limited to this. It is possible to use a phosphor layer that emits fluorescence of any color.

  In the present embodiment, the light emitted from the light source device 100 is synthesized by the synthesis optical system 80. However, the present invention is not limited to this, and the first excitation light B1 and the fluorescence RG are emitted separately. It doesn't matter.

  In the present embodiment, the dichroic mirror 60 is provided between the first synthesis mirror 81 and the pickup lens 50. However, the present invention is not limited to this, and the gap between the first synthesis mirror 81 and the second synthesis mirror 82 is provided. A dichroic mirror 60 may be provided.

  In the present embodiment, the laser light B emitted from the light source unit 10 is separated by the light guide optical system 30, but only the light that excites the light emitting element 40 may be emitted from the light source unit 10. . In that case, in order to perform full color display with the projector PJ, it is preferable to prepare a blue light source separately.

  In the present embodiment, the light emitting element 40 having a configuration in which the substrate 41 rotates around the rotation axis is used. However, the light emitting element can be fixed.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  DESCRIPTION OF SYMBOLS 10 ... Light source, 11 ... Semiconductor laser light source (solid light source), 30 ... Light guide optical system, 41 ... Substrate, 43 ... Wavelength selection film, 45 ... Phosphor layer, 50 ... Pick-up lens (condensing optical system), 60 ... Dichroic mirror (wavelength selection mirror), 70 ... light diffusing member, 80 ... synthesis optical system, 100 ... light source device, 400R, 400G, 400B ... liquid crystal light valve (light modulation element), 600 ... projection optical system, AR ... annular region , PJ ... projector, RG ... fluorescence,

Claims (11)

A substrate,
A phosphor layer provided on the substrate;
A light source that emits light including first light that excites the phosphor;
A wavelength selection mirror that transmits light corresponding to a wavelength band of fluorescence emitted from the phosphor layer and reflects light corresponding to a peak wavelength of transmitted light transmitted through the phosphor layer among the first light;
A condensing optical system provided on the optical path of the transmitted light between the wavelength selective mirror and the phosphor layer ,
The light source device , wherein the substrate is made of a material that transmits at least light corresponding to a peak wavelength of the first light . Before SL phosphor layer, the light source apparatus according to claim 1, characterized in that provided on the side opposite to the side where the first light is incident to the substrate. The substrate is provided to be rotatable around a predetermined rotation axis,
The light source device according to claim 1, wherein the phosphor layer is provided in an annular area around the rotation axis on the substrate. A light guide optical system that divides the first light and the second light from the light emitted from the light source;
The light source device according to claim 1, wherein the fluorescent light and the second light are emitted.   The light source device according to claim 4, further comprising a combining optical system that combines the fluorescence and the second light.   The light source device according to claim 4, wherein the first light is a color light of a complementary color of the fluorescence.   Between the phosphor layer and the surface of the substrate on which the first light is incident, overlaps the phosphor layer in a plan view and transmits light corresponding to the peak wavelength of the first light. The light source device according to claim 1, further comprising a wavelength selection film that reflects light corresponding to the fluorescence wavelength band.   The light source device according to claim 1, wherein the light source emits light in a blue wavelength band as the first light.   The light source device according to claim 1, wherein the light source is a solid light source.   The light source device according to claim 9, wherein the light source is a semiconductor laser.   11. A light source device according to claim 1, a light modulation element that modulates light emitted from the light source device, and a projection optical system that projects light modulated by the light modulation element. A projector characterized by that.

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