Light source device and projector

Abstract

To provide a light source device excellent in light use efficiency.SOLUTION: A light source device includes: a first light source that emits first light; a wavelength conversion element that converts the first light into second light; a first optical member that is disposed between the first light source and the wavelength conversion element, and transmits the first light to reflect the second light; and a first reflective member that reflects the first light and the second light. A first air layer is provided between the first optical member and the wavelength conversion element. The wavelength conversion element has: a first surface on which the first light is incident via the first optical member and the first air layer; a second surface facing an opposite side to the first surface; and a third surface and a fourth surface crossing the first surface and the second surface, and facing sides opposite to each other. The first reflective member is disposed in a region at a third surface side of the first air layer. The second light emitted from the first surface of the wavelength conversion element propagates through the first air layer and is emitted from a region at a fourth surface side of the first air layer.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a light source device and a projector.

Background Art

[0002] As a light source device used in a projector, a light source device that utilizes fluorescence emitted from a phosphor when excitation light emitted from a light-emitting element irradiates the phosphor has been proposed. Patent Document 1 below discloses a light source device including a flat wavelength conversion member containing a phosphor and a light-emitting diode that emits excitation light. In this light source device, among the plurality of surfaces of the wavelength conversion member, excitation light is incident from an incident surface having a large area, and fluorescence is emitted from an emission surface having a small area.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the light source device of Patent Document 1, the fluorescence generated inside the wavelength conversion member propagates inside the wavelength conversion member by total reflection at the interface between the surface of the wavelength conversion member and the air layer, and is emitted from the emission surface. However, among the fluorescence, the component incident on the interface between the wavelength conversion member and the air layer at an angle less than the critical angle is not totally reflected at the interface, so it leaks to the outside from the interface before reaching the emission surface. Therefore, there is a problem that the utilization efficiency of fluorescence decreases.

Means for Solving the Problems

[0005] To solve the above problems, a light source device according to one aspect of the present invention includes a first light source that emits first light in a first wavelength band, a wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band, a first optical member that is disposed between the first light source and the wavelength conversion element and transmits the first light and reflects the second light, and a first reflection member that reflects the first light and the second light. A first air layer is provided between the first optical member and the wavelength conversion element. The wavelength conversion element has a first surface on which the first light transmitted through the first optical member is incident via the first air layer, a second surface facing the opposite side of the first surface, and a third surface and a fourth surface that intersect the first surface and face opposite sides of each other. The first reflection member is disposed in a region on the third surface side of the first air layer. The second light emitted from the first surface of the wavelength conversion element propagates through the first air layer and is emitted from a region on the fourth surface side of the first air layer.

[0006] A projector according to one aspect of the present invention includes a light source device according to one aspect of the present invention, a light modulation device that modulates light emitted from the light source device, and a projection optical device that projects the light modulated by the light modulation device.

Brief Description of the Drawings

[0007]

Figure 1

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[0008] [First Embodiment] Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. The projector of this embodiment is an example of a projector using a liquid crystal panel as a light modulation device. In the following drawings, for ease of viewing each component, the scale of the dimensions may be varied depending on the component.

[0009] FIG. 1 is a schematic configuration diagram of the projector 1 of this embodiment. As shown in FIG. 1, the projector 1 of this embodiment is a projection type image display device that displays a color image on a screen SCR which is a projection surface. The projector 1 includes three light modulation devices corresponding to each color light of red light LR, green light LG, and blue light LB.

[0010] The projector 1 includes a first lighting device 20, a second lighting device 21, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a light combining element 5, and a projection optical device 6.

[0011] The first lighting device 20 emits yellow fluorescence Y toward the color separation optical system 3. The second lighting device 21 emits blue light LB toward the light modulation device 4B. The detailed configurations of the first lighting device 20 and the second lighting device 21 will be described later.

[0012] Hereinafter, in the drawings, explanations will be made using the XYZ orthogonal coordinate system as necessary. The Z-axis is an axis along the vertical direction of the projector 1. The X-axis is an axis parallel to the optical axis AX1 of the first lighting device 20 and the optical axis AX2 of the second lighting device 21, and is an axis along the front-rear direction of the projector 1. The Y-axis is an axis orthogonal to the X-axis and the Z-axis, and is an axis along the left-right direction of the projector 1. These notations are for explaining the arrangement relationship of each component of the projector 1, and do not limit the installation posture and direction of the projector 1. The optical axis AX1 of the first lighting device 20 is the central axis of the fluorescent light Y emitted from the first lighting device 20. The optical axis AX2 of the second lighting device 21 is the central axis of the blue light LB emitted from the second lighting device 21.

[0013] One of the two directions along the X-axis is referred to as the +X direction, and the opposite direction is referred to as the -X direction. One of the two directions along the Y-axis is referred to as the +Y direction, and the opposite direction is referred to as the -Y direction. One of the two directions along the Z-axis is referred to as the +Z direction, and the opposite direction is referred to as the -Z direction. When collectively referring to the two directions along the X-axis without distinction, it is referred to as the X-axis direction. When collectively referring to the two directions along the Y-axis without distinction, it is referred to as the Y-axis direction. When collectively referring to the two directions along the Z-axis without distinction, it is referred to as the Z-axis direction.

[0014] The color separation optical system 3 separates the yellow fluorescent light Y emitted from the first lighting device 20 into red light LR and green light LG. The color separation optical system 3 includes a dichroic mirror 7, a first reflection mirror 8a, and a second reflection mirror 8b.

[0015] The dichroic mirror 7 separates the fluorescence Y into red light LR and green light LG. The dichroic mirror 7 transmits the red light LR and reflects the green light LG. The second reflection mirror 8b is disposed in the optical path of the green light LG. The second reflection mirror 8b reflects the green light LG reflected by the dichroic mirror 7 toward the optical modulation device 4G. The first reflection mirror 8a is disposed in the optical path of the red light LR. The first reflection mirror 8a reflects the red light LR transmitted through the dichroic mirror 7 toward the optical modulation device 4R.

[0016] On the other hand, the blue light LB emitted from the second illumination device 21 is reflected by the reflection mirror 9 toward the optical modulation device 4B.

[0017] Hereinafter, the configuration of the second illumination device 21 will be described. The second illumination device 21 includes a light source unit 81, a condenser lens 82, a diffusion plate 83, a rod lens 86, and a relay lens 87. The light source unit 81 is composed of at least one semiconductor laser. The light source unit 81 emits blue light LB composed of laser light. Note that the light source unit 81 is not limited to a semiconductor laser and may be composed of an LED that emits blue light.

[0018] The condenser lens 82 is composed of a convex lens. The condenser lens 82 makes the blue light LB emitted from the light source unit 81 incident on the diffusion plate 83 in a substantially condensed state. The diffusion plate 83 diffuses the blue light LB emitted from the condenser lens 82 with a predetermined diffusion degree to generate blue light LB having a substantially uniform light distribution similar to the fluorescence Y emitted from the first illumination device 20. As the diffusion plate 83, for example, ground glass made of optical glass is used.

[0019] The blue light LB diffused by the diffusion plate 83 enters the rod lens 86. The rod lens 86 has a prismatic shape extending along the optical axis AX2 direction of the second lighting device 21. The rod lens 86 has a light incident end face 86a provided at one end and a light emitting end face 86b provided at the other end. The diffusion plate 83 is fixed to the light incident end face 86a of the rod lens 86 via an optical adhesive (not shown). It is desirable that the refractive index of the diffusion plate 83 and the refractive index of the rod lens 86 match as much as possible.

[0020] The blue light LB is emitted from the light emitting end face 86b in a state where the uniformity of the illuminance distribution is enhanced by propagating while totally reflecting inside the rod lens 86. The blue light LB emitted from the rod lens 86 enters the relay lens 87. The relay lens 87 makes the blue light LB with enhanced illuminance distribution uniformity by the rod lens 86 enter the reflection mirror 9.

[0021] The shape of the light emitting end face 86b of the rod lens 86 is a rectangular shape that is substantially similar to the shape of the image formation region of the light modulation device 4B. Thereby, the blue light LB emitted from the rod lens 86 efficiently enters the image formation region of the light modulation device 4B.

[0022] The light modulation device 4R modulates the red light LR according to the image information and forms image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to the image information and forms image light corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to the image information and forms image light corresponding to the blue light LB.

[0023] For each of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, for example, a transmissive liquid crystal panel is used. Also, polarizing plates (not shown) are respectively arranged on the incident side and the emission side of the liquid crystal panel. The polarizing plate allows only linearly polarized light in a specific direction to pass through.

[0024] A field lens 10R is disposed on the incident side of the optical modulation device 4R. A field lens 10G is disposed on the incident side of the optical modulation device 4G. A field lens 10B is disposed on the incident side of the optical modulation device 4B. The field lens 10R collimates the principal ray of the red light LR incident on the optical modulation device 4R. The field lens 10G collimates the principal ray of the green light LG incident on the optical modulation device 4G. The field lens 10B collimates the principal ray of the blue light LB incident on the optical modulation device 4B.

[0025] When the image light emitted from the optical modulation devices 4R, 4G, and 4B is incident on the light synthesizing element 5, the light synthesizing element 5 synthesizes the image light corresponding to the red light LR, the green light LG, and the blue light LB, and emits the synthesized image light toward the projection optical device 6. For example, a cross dichroic prism is used as the light synthesizing element 5.

[0026] The projection optical device 6 is composed of a plurality of projection lenses. The projection optical device 6 magnifies and projects the image light synthesized by the light synthesizing element 5 toward the screen SCR. Thereby, an image is displayed on the screen SCR.

[0027] Hereinafter, the configuration of the first lighting device 20 will be described. The first lighting device 20 includes a light source device 30A, an integrator optical system 70, a polarization conversion element 63, and a superimposing optical system 64.

[0028] FIG. 2 is a perspective view of the light source device 30A of the present embodiment. FIG. 3 is a cross-sectional view of the light source device 30A taken along line III-III of FIG. 2. FIG. 4 is a cross-sectional view of the light source device 30A taken along line IV-IV of FIG. 2.

[0029] As shown in FIGS. 2 to 4, the light source device 30A includes a support member 29, a housing 31, a first light source 41, a wavelength conversion element 50, a first optical member 55, a first reflecting member 53, and a second reflecting member 54.

[0030] The support member 29 supports the wavelength conversion element 50. The wavelength conversion element 50 is connected to the support member 29 so as to be heat-transferable. Thereby, the support member 29 functions as a heat-radiating member that diffuses the heat generated in the wavelength conversion element 50 and releases it to the outside. For this reason, it is desirable that the support member 29 has a predetermined strength and is made of a material with high thermal conductivity. As the material of the support member 29, for example, metals such as aluminum and stainless steel are used, and in particular, it is desirable to use an aluminum alloy such as 6061 series. According to this configuration, since the heat of the wavelength conversion element 50 is released to the outside through the support member 29, the temperature rise of the wavelength conversion element 50 can be suppressed. As a result, it is possible to suppress a decrease in the wavelength conversion efficiency accompanying the temperature rise of the wavelength conversion element 50.

[0031] As shown in FIG. 4, the support member 29 has a base portion 32 and a support portion 33. The base portion 32 is a plate-like member forming the main body of the support member 29 and extends long in the X-axis direction. The support portion 33 is integrally formed with the base portion 32 and is provided on the surface 32a located on the +Y side of the base portion 32. The support portion 33 has a groove 34 for supporting the wavelength conversion element 50. The groove 34 extends in the X-axis direction along the longitudinal direction of the support portion 33 and houses the wavelength conversion element 50. The groove 34 has a bottom surface 34a along the XZ plane and a pair of inner wall surfaces 34b arranged apart from each other in the Z-axis direction and along the XY plane. A pair of second reflecting members 54, which will be described later, are arranged on each of the inner wall surfaces 34b of the groove 34. In the present embodiment, the height T1 of the support portion 33 in the Y-axis direction is higher than the height T2 of the wavelength conversion element 50 in the Y-axis direction.

[0032] As shown in FIG. 2, the housing 31 constitutes the exterior of the light source device 30A together with the support member 29. The housing 31 has a substantially box-shaped shape with one side open. The housing 31 has a top wall portion 31a, a first side wall portion 31c, a second side wall portion 31d, a third side wall portion 31e, a fourth side wall portion 31f, and an outlet 31k.

[0033] The top wall portion 31a is arranged along the XZ plane. The first side wall portion 31c and the second side wall portion 31d intersect the X-axis along the longitudinal direction of the wavelength conversion element 50 and are located on opposite sides in the X-axis direction. The first side wall portion 31c is located on the -X side which is one side in the X-axis direction. The second side wall portion 31d is located on the +X side which is the other side in the X-axis direction. The third side wall portion 31e and the fourth side wall portion 31f are located on opposite sides in the Z-axis direction which intersects the longitudinal direction of the wavelength conversion element 50. In the present embodiment, the third side wall portion 31e is located on the +Z side which is one side in the Z-axis direction. The fourth side wall portion 31f is located on the -Z side which is the other side in the Z-axis direction.

[0034] The first light source 41 is arranged on the top wall portion 31a of the housing 31. The first reflecting member 53 is arranged on the first side wall portion 31c of the housing 31. The outlet 31k is provided on the second side wall portion 31d of the housing 31. The outlet 31k is an opening for taking out the fluorescence Y emitted from the first air layer 57 and the wavelength conversion element 50 to the outside.

[0035] The top wall portion 31a is connected to the first light source 41 in a heat-transferable manner. For this reason, it is desirable that the housing 31 be made of a material having a predetermined strength and a high thermal conductivity. As the material of the housing 31, similar to the support member 29, for example, metals such as aluminum and stainless steel are used, and in particular, it is desirable to use an aluminum alloy such as 6061 series.

[0036] The housing 31 covers the support portion 33 of the support member 29 and is arranged so as to abut against the surface 32a of the base portion 32 of the support member 29. That is, the housing 31 covers the first optical member 55 supported by the groove 34 and the wavelength conversion element 50. The housing 31 and the support member 29 are fixed to each other via fixing members such as adhesives and screws (not shown).

[0037] Thus, in the light source device 30A, the first optical member 55, the wavelength conversion element 50, and the first light source 41 are accommodated in a space surrounded by the housing 31 and the support member 29. Thereby, adhesion of foreign matters such as dust to the first optical member and the wavelength conversion element 50 can be suppressed.

[0038] The first light source 41 includes a plurality of first light emitting elements 41a and a substrate 41b. The plurality of first light emitting elements 41a are mounted on the substrate 41b. Note that the number of the first light emitting elements 41a is not particularly limited. Therefore, the first light source 41 does not necessarily have to include a plurality of first light emitting elements 41a, and may have one first light emitting element 41a.

[0039] The first light emitting element 41a emits excitation light rays E1 in a first wavelength band. The first light emitting element 41a is composed of, for example, a light emitting diode (LED). The first light emitting element 41a is disposed to face the wavelength conversion element 50 and emits the excitation light rays E1 toward the wavelength conversion element 50. The first wavelength band is, for example, a wavelength band ranging from purple to blue of 400 nm to 480 nm, and the peak wavelength is, for example, 445 nm. The plurality of first light emitting elements 41a are arranged along the X-axis direction which is the longitudinal direction of the wavelength conversion element 50. In this way, the first light source 41 emits excitation light E composed of a plurality of blue excitation light rays E1 toward the wavelength conversion element 50.

[0040] The wavelength conversion element 50 has a plate-like shape extending along the X-axis and has six faces. The side of the wavelength conversion element 50 extending along the X-axis is longer than the side extending along the Y-axis and the side extending along the Z-axis. The X-axis direction corresponds to the longitudinal direction of the wavelength conversion element 50. The Y-axis direction is a direction parallel to the shortest side among the sides of the wavelength conversion element 50. The length of the side along the Y-axis is shorter than the length of the side along the Z-axis. That is, the cross-sectional shape of the wavelength conversion element 50 cut along the plane along the YZ plane is rectangular as shown in FIG. 4.

[0041] The wavelength conversion element 50 has a front surface 50a, a back surface 50b, a first end surface 50c, a second end surface 50d, a first side surface 50e, and a second side surface 50f. The front surface 50a and the back surface 50b intersect the Y-axis and face opposite sides on the Y-axis. In the present embodiment, the front surface 50a is the surface located on the +Y side, which is one side in the Y-axis direction. The back surface 50b is the surface located on the -Y side, which is the other side in the Y-axis direction, and is in contact with the bottom surface 34a of the groove 34 of the support member 29. That is, the back surface 50b of the wavelength conversion element 50 is connected to the support member 29 so as to be thermally conductive. The excitation light E is incident on the front surface 50a through the first optical member 55 and the first air layer 57. The front surface 50a of the present embodiment corresponds to the first surface in the claims. The back surface 50b of the present embodiment corresponds to the second surface in the claims. Note that a reflective film may be formed on the back surface 50b of the wavelength conversion element 50, and the fluorescence Y emitted from the back surface 50b may be reflected by the reflective film and returned into the wavelength conversion element 50.

[0042] As shown in FIG. 3, the first end surface 50c and the second end surface 50d intersect the front surface 50a and the back surface 50b and face opposite sides in the X-axis direction along the longitudinal direction of the wavelength conversion element 50. In the present embodiment, the first end surface 50c is located on the -X side, which is one side in the X-axis direction. The second end surface 50d is located on the +X side, which is the other side in the X-axis direction. The first end surface 50c of the present embodiment corresponds to the third surface in the claims. The second end surface 50d of the present embodiment corresponds to the fourth surface in the claims.

[0043] As shown in FIG. 4, the first side surface 50e and the second side surface 50f intersect the front surface 50a, the back surface 50b, the first end surface 50c, and the second end surface 50d and face opposite sides in the Z-axis direction. In the present embodiment, the first side surface 50e is located on the +Z side, which is one side in the Z-axis direction, and the second side surface 50f is located on the -Z side, which is the other side in the Z-axis direction. The first side surface 50e of the present embodiment corresponds to the fifth surface in the claims. The second side surface 50f of the present embodiment corresponds to the sixth surface in the claims.

[0044] The wavelength conversion element 50 includes at least a yellow phosphor, and converts the excitation light E in the first wavelength band emitted from the plurality of light-emitting elements 41a of the first light source 41 into yellow fluorescence Y in a second wavelength band different from the first wavelength band. The excitation light E enters the wavelength conversion element 50 from the surface 50a through the first optical member 55 and the first air layer 57. Further, the fluorescence Y generated inside the wavelength conversion element 50 is emitted from the surface 50a to the first air layer 57. The excitation light E in the present embodiment corresponds to the first light in the claims.

[0045] The wavelength conversion element 50 includes a ceramic phosphor made of a polycrystalline phosphor that wavelength-converts the excitation light E into fluorescence Y. The wavelength conversion element 50 in the present embodiment is composed of a phosphor having no light scattering property, so-called a transparent phosphor. The second wavelength band of the fluorescence Y is, for example, a yellow wavelength band of 490 to 750 nm. That is, the fluorescence Y is yellow fluorescence including a red light component and a green light component. The fluorescence Y in the present embodiment corresponds to the second light in the claims.

[0046] Instead of the polycrystalline phosphor, the wavelength conversion element 50 may include a single crystal phosphor. Alternatively, the wavelength conversion element 50 may be composed of fluorescent glass. Alternatively, the wavelength conversion element 50 may be composed of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin. The wavelength conversion element 50 made of such a material converts the excitation light E into fluorescence Y.

[0047] Specifically, the material of the wavelength conversion element 50 includes, for example, a yttrium aluminum garnet (YAG) - based phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, as the material of the wavelength conversion element 50, a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and subjecting them to a solid-phase reaction, Y - Al - O amorphous particles obtained by a wet method such as a coprecipitation method or a sol - gel method, YAG particles obtained by a gas-phase method such as a spray drying method, a flame pyrolysis method, or a thermal plasma method, etc. are used.

[0048] The first optical member 55 is disposed between the first light source 41 and the wavelength conversion element 50. Specifically, as shown in FIG. 4, the first optical member 55 is disposed on the surface 33a of the support portion 33 that faces the first light source 41. The first optical member 55 includes a first light-transmitting member 51 and a first optical layer 52.

[0049] The first light-transmitting member 51 is made of a light-transmitting material such as borosilicate glass like BK7, quartz, synthetic quartz, crystal, SiC, GaN, MgO, YAG, sapphire, and diamond. The first light-transmitting member 51 needs to be made of a material that can at least transmit the excitation light E. The first light-transmitting member 51 has a plate-like shape extending along the X-axis. As shown in FIG. 4, the first light-transmitting member 51 has a rectangular cross-sectional shape when cut along the plane along the YZ plane and extends long in the X-axis direction.

[0050] Note that it is desirable that the thermal conductivity of the first light-transmitting member 51 is greater than the thermal conductivity of the wavelength conversion element 50. Materials for the first light-transmitting member 51 that satisfy this relationship are, for example, SiC, GaN, MgO, YAG, sapphire, and diamond. According to this configuration, since the heat of the wavelength conversion element 50 is efficiently transmitted to the first light-transmitting member 51 through the first air layer 57, the temperature rise of the wavelength conversion element 50 can be suppressed. Thereby, a decrease in luminous efficiency associated with the temperature rise of the wavelength conversion element 50 can be suppressed.

[0051] The first optical layer 52 has optical characteristics of transmitting the excitation light E and reflecting the fluorescence Y. The first optical layer 52 is constituted by, for example, a dielectric multilayer film. The first optical layer 52 is disposed between the wavelength conversion element 50 and the first light-transmitting member 51. That is, the first optical layer 52 is provided on the surface of the first light-transmitting member 51 that faces the wavelength conversion element 50 among the two surfaces. According to this configuration, as will be described later, the fluorescence Y does not enter the first light-transmitting member 51 and does not propagate inside the first light-transmitting member 51, so that the loss of the fluorescence Y can be minimized.

[0052] A first air layer 57 is provided between the first optical member 55 and the wavelength conversion element 50. That is, the first optical member 55 and the wavelength conversion element 50 are arranged apart from each other, and air exists between the first optical member 55 and the wavelength conversion element 50. In the case of the present embodiment, since the height T1 of the support portion 33 in the Y-axis direction is higher than the height T2 of the wavelength conversion element 50 in the Y-axis direction, and the first optical member 55 is arranged on the surface 33a of the support portion 33 facing the first light source 41, the state in which the first air layer 57 exists between the first optical member 55 and the wavelength conversion element 50 is stably maintained.

[0053] As shown in FIG. 3, the first reflecting member 53 is arranged on the -X side in the X-axis direction of the wavelength conversion element 50, the first air layer 57, the first optical member 55, and the first light source 41. The first reflecting member 53 is provided on the first side wall portion 31c of the housing 31 so as to face the first end face 50c of the wavelength conversion element 50, the region on the first end face 50c side of the first air layer 57, the end face on the first end face 50c side of the first optical member 55, and the end face on the first end face 50c side of the first light source 41. Note that the first reflecting member 53 does not necessarily need to be provided over all of the above regions, and it may be provided at least in the region on the first end face 50c side of the first air layer 57.

[0054] The first reflecting member 53 reflects the fluorescence Y that has propagated inside the first air layer 57 and the wavelength conversion element 50 and has reached the first reflecting member 53. Further, the first reflecting member 53 reflects the excitation light E that has been reflected by the surface 50a of the wavelength conversion element 50 and has propagated inside the first air layer 57 and has reached the first reflecting member 53. That is, the first reflecting member 53 reflects the fluorescence Y and the excitation light E. The first reflecting member 53 is composed of, for example, a metal film, a dielectric multilayer film, a scattering member made of barium sulfate, or the like.

[0055] As shown in FIG. 4, a pair of second reflecting members 54 are located on both sides of the first air layer 57 and the wavelength conversion element 50 in the Z-axis direction. One of the second reflecting members 54 is provided on the inner wall surface 34b of the groove 34 of the support member 29 so as to face the region on the first side surface 50e side of the wavelength conversion element 50 and the first side surface 50e side of the first air layer 57. The other second reflecting member 54 is provided on the inner wall surface 34b of the groove 34 of the support member 29 so as to face the region on the second side surface 50f side of the wavelength conversion element 50 and the second side surface 50f side of the first air layer 57.

[0056] The second reflecting member 54 reflects the excitation light E that is reflected by the surface 50a of the wavelength conversion element 50 and enters the first air layer 57, and then reflects the excitation light E that reaches the second reflecting member 54 and makes it enter the wavelength conversion element 50. Thereby, the conversion efficiency from the excitation light E to the fluorescence Y can be increased. Also, the second reflecting member 54 reflects the fluorescence Y that is emitted from the wavelength conversion element 50 and enters the first air layer 57 and reaches the second reflecting member 54, and the fluorescence Y that guides through the inside of the wavelength conversion element 50 and reaches the second reflecting member 54. Thereby, the loss of the fluorescence Y can be suppressed. That is, the second reflecting member 54 reflects the fluorescence Y and the excitation light E. The second reflecting member 54 is composed of, for example, a metal film, a dielectric multilayer film, a scattering member, etc.

[0057] As shown in FIG. 1, an integrator optical system 70 is provided on the light emission side of the light source device 30A. The integrator optical system 70 has a first lens array 61 and a second lens array 62. The integrator optical system 70 functions as a uniform illumination optical system that equalizes the intensity distribution of the fluorescence Y emitted from the light source device 30A together with the superimposing optical system 64 in each of the light modulation devices 4R and 4G that are the illuminated regions. The fluorescence Y emitted from the light source device 30A enters the first lens array 61.

[0058] The first lens array 61 has a plurality of first lenses 61a. The plurality of first lenses 61a are arranged in a matrix in a plane parallel to the YZ plane orthogonal to the optical axis AX1 of the first illumination device 20. The plurality of first lenses 61a divide the fluorescent light Y emitted from the light source device 30A into a plurality of partial light beams. The shape of each of the first lenses 61a is a rectangular shape that is substantially similar to the shape of the image formation regions of the light modulation devices 4R and 4G. Thereby, each of the partial light beams emitted from the first lens array 61 efficiently enters the image formation regions of the light modulation devices 4R and 4G, respectively.

[0059] The fluorescent light Y emitted from the first lens array 61 travels toward the second lens array 62. The second lens array 62 is disposed to face the first lens array 61. The second lens array 62 has a plurality of second lenses 62a corresponding to the plurality of first lenses 61a of the first lens array 61. The second lens array 62, together with the superimposing optical system 64, forms an image of each of the plurality of first lenses 61a of the first lens array 61 in the vicinity of the image formation regions of the light modulation devices 4R and 4G. The plurality of second lenses 62a are arranged in a matrix in a plane parallel to the YZ plane orthogonal to the optical axis AX1 of the first illumination device 20. The superimposing optical system 64 is composed of one convex lens.

[0060] In the present embodiment, each of the first lenses 61a of the first lens array 61 and each of the second lenses 62a of the second lens array 62 have the same size as each other, but may have different sizes from each other. Also, in the present embodiment, the first lenses 61a of the first lens array 61 and the second lenses 62a of the second lens array 62 are arranged at positions where their optical axes coincide with each other, but may be arranged in an eccentric state with respect to each other.

[0061] The polarization conversion element 63 converts the polarization direction of the fluorescence Y emitted from the second lens array 62. Specifically, the polarization conversion element 102 is divided by the first lens array 61 and converts each partial light beam of the fluorescence Y emitted from the second lens array 62 into linearly polarized light. The polarization conversion element 63 includes a polarization separation layer (not shown), a reflection layer (not shown), and a retardation layer (not shown). The polarization separation layer transmits one linearly polarized component of the polarization components included in the fluorescence Y emitted from the light source device 30A as it is, and reflects the other linearly polarized component in a direction perpendicular to the optical axis AX1. The reflection layer reflects the other linearly polarized component reflected by the polarization separation layer in a direction parallel to the optical axis AX1. The retardation layer converts the other linearly polarized component reflected by the reflection layer into one linearly polarized component.

[0062] Hereinafter, the behavior of light in the light source device 30A of the present embodiment will be described. As shown in FIG. 3, in the light source device 30A, the excitation light E emitted from the first light source 41 passes through the first light transmissive member 51 and the first optical layer 52, and enters the wavelength conversion element 50 through the first air layer 57. Note that a part of the excitation light E is backscattered from the surface 50a of the wavelength conversion element 50 and travels toward the first light source 41 side, but is reflected by the first optical layer 52 and the first light transmissive member 51 and enters the wavelength conversion element 50.

[0063] When the excitation light E enters the wavelength conversion element 50, the phosphor contained inside the wavelength conversion element 50 is excited, and fluorescence Y is emitted from an arbitrary light emitting point. At this time, the excitation light E incident on the phosphor is diffused and propagates in a region wider than the incident region, so that the width of the emission region of the fluorescence Y, so-called, bleeding of the fluorescence Y occurs.

[0064] Fluorescence Y that is incident on the surface 50a of the wavelength conversion element 50 at an incident angle less than the critical angle enters the first air layer 57 after being emitted from the wavelength conversion element 50 and propagates inside the first air layer 57. At this time, the fluorescence Y1 that travels toward the +X side is reflected by the first optical layer 52 of the first optical member 55 and enters the wavelength conversion element 50 again. In the case of this embodiment, since the wavelength conversion element 50 is composed of a transparent phosphor, scattering of the fluorescence Y does not occur inside the wavelength conversion element 50, and the traveling direction of the fluorescence Y1 inside the wavelength conversion element 50 does not change. For this reason, the fluorescence Y1 is reflected by the back surface 50b of the wavelength conversion element 50, enters the first air layer 57 from the surface 50a of the wavelength conversion element 50, and is emitted from the region on the second end surface 50d side of the first air layer 57. Also, the fluorescence Y2 that is reflected by the first optical layer 52 of the first optical member 55, enters the wavelength conversion element 50, and is reflected by the back surface 50b is emitted from the second end surface 50d. That is, the fluorescence Y propagates inside the first air layer 57 and the wavelength conversion element 50 while repeating back surface reflection by the wavelength conversion element 50 and reflection by the first optical layer 52, and is emitted from the region on the second end surface 50d side of the first air layer 57 or from the second end surface 50d of the wavelength conversion element 50. On the other hand, the fluorescence Y that travels toward the -X side and reaches the first reflection member 53, after being reflected by the first reflection member 53, travels toward the +X side, repeats reflection between the first optical layer 52 of the first optical member 55 and the back surface 50b of the wavelength conversion element 50, and is emitted from the region on the second end surface 50d side of the first air layer 57 or from the second end surface 50d of the wavelength conversion element 50.

[0065] In contrast, fluorescence Y3 that is incident on the surface 50a of the wavelength conversion element 50 at an incident angle equal to or greater than the critical angle is reflected by the surface 50a and guides light inside the wavelength conversion element 50. In the case of the present embodiment, since the wavelength conversion element 50 is composed of a transparent phosphor, scattering of the fluorescence Y3 does not occur inside the wavelength conversion element 50, and the incident angle of the fluorescence Y3 with respect to the surface 50a of the wavelength conversion element 50 does not change. Therefore, the fluorescence Y3 that travels toward the +X side is repeatedly reflected between the front surface 50a and the back surface 50b of the wavelength conversion element 50 and is emitted from the second end face 50d. On the other hand, the fluorescence Y4 that travels toward the -X side, like the fluorescence Y2 that travels through the first air layer 57, is reflected by the first reflection member 53 and then travels toward the +X side, is repeatedly reflected between the front surface 50a and the back surface 50b of the wavelength conversion element 50, and is emitted from the second end face 50d.

[0066] In the light source device 30A, among the fluorescence Y generated by the wavelength conversion element 50, some of the fluorescence Y1 and Y2 are emitted from the region on the second end face 50d side of the first air layer 57, and some of the other fluorescence Y3 and Y4 are emitted from the second end face 50d of the wavelength conversion element 50. In this way, the light source device 30A can emit the fluorescence Y generated by the wavelength conversion element 50 to the outside through the outlet 31k of the housing 31.

[0067] As shown in FIG. 2, in a state of viewing in a plan view in the X-axis direction, which is the normal direction of the second end face 50d of the wavelength conversion element 50, the outlet 31k overlaps the first air layer 57 and the wavelength conversion element 50. Therefore, the region on the second end face 50d side of the first air layer 57 and the second end face 50d of the wavelength conversion element 50 are exposed to the outside through the outlet 31k. The outlet 31k may be blocked by a lid made of a light-transmitting member, and the region on the second end face 50d side of the first air layer 57 and the second end face 50d of the wavelength conversion element 50 may not be exposed to the outside. However, when the lid is provided, a part of the fluorescence Y may be reflected by the surface of the lid and may not be taken out to the outside. Therefore, in order to improve the extraction efficiency of the fluorescence Y, it is desirable that the lid is not provided. In the example of FIG. 2, the outlet 31k overlaps the first optical layer 52 in addition to the first air layer 57 and the wavelength conversion element 50, but it does not have to overlap the first optical layer 52.

[0068] In this way, the light source device 30A can extract the fluorescence Y emitted from the region on the second end face 50d side of the first air layer 57 and the second end face 50d of the wavelength conversion element 50 to the outside through the minimum extraction port 31k. As a result, the étendue of the fluorescence Y becomes small, and the loss of the fluorescence Y in optical members such as the integrator optical system 70 arranged in the subsequent stage of the light source device 30A can be reduced. Consequently, the utilization efficiency of the fluorescence Y in the light source device 30A can be improved.

[0069] Hereinafter, the effect of the fluorescence Y propagating through the first air layer 57 will be described. FIG. 5 is a schematic diagram for explaining the operation of the light source device 30A of the present embodiment. When guiding the fluorescence Y emitted from the wavelength conversion element 50 through an arbitrary medium to the extraction port 31k, instead of the air layer as in the present embodiment, a configuration in which a light-transmitting member such as quartz is adjacent to the wavelength conversion element 50 and the fluorescence is guided through the light-transmitting member can also be considered. This configuration is taken as a comparative example.

[0070] In the case of the comparative example, as shown in FIG. 5, when the fluorescence Y generated by the wavelength conversion element 50 reaches the interface K between the wavelength conversion element 50 and the light-transmitting member 60, if the incident angle α of the fluorescence Y with respect to the interface K is less than the critical angle, the fluorescence Y refracts at the refractive angle β1 without reflecting at the interface K and enters the light-transmitting member 60. Here, assuming that the material of the wavelength conversion element 50 is YAG and the material of the light-transmitting member 60 is quartz, since the refractive index of YAG is about 1.7 and the refractive index of quartz is about 1.4, the refractive index difference between the wavelength conversion element 50 and the light-transmitting member 60 is about 0.3, and the refractive index difference is relatively small.

[0071] In this case, the refraction angle β1 does not become much larger with respect to the incident angle α, and the fluorescence Y5 incident on the light-transmitting member 60 travels in a direction close to perpendicular to the interface K, that is, in a direction forming a large angle with respect to the X-axis. As a result, the fluorescence Y5 may leak to the outside from the surface 60b on the side opposite to the interface K of the light-transmitting member 60 and become leakage light Y6. Or, even if the fluorescence Y5 becomes fluorescence Y7 reflected by the surface 60b of the light-transmitting member 60, when the fluorescence Y7 reaches the end face 60d of the light-transmitting member 60 while propagating in the X-axis direction through the light-transmitting member 60, since the incident angle of the fluorescence Y7 with respect to the end face 60d is large, the fluorescence Y7 may be reflected by the end face 60d and not be emitted from the end face 60d, and there is a possibility that the extraction efficiency of the fluorescence Y decreases.

[0072] On the other hand, when the first air layer 57 is adjacent to the wavelength conversion element 50 as in the present embodiment, since the refractive index of YAG is about 1.7 and the refractive index of air is about 1.0, the refractive index difference between the wavelength conversion element 50 and the first air layer 57 is about 0.7, which is larger than that in the comparative example. Therefore, the refraction angle β2 becomes larger than the refraction angle β1, and the fluorescence Y8 incident on the first air layer 57 travels in a direction forming a smaller angle with respect to the interface K, that is, in a direction forming a smaller angle with respect to the X-axis, compared to the case of being incident on the light-transmitting member 60. As a result, when the fluorescence Y8 reaches the interface between the first air layer 57 and another substance, it is likely to undergo total reflection and is less likely to leak to the outside. Also, in the case of the present embodiment, since the first air layer 57 is opened to the external space at the extraction port 31k and does not have a refractive index interface, the fluorescence Y8 that reaches the extraction port 31k is emitted directly into the external space without undergoing reflection or refraction. Due to the above actions, according to the light source device 30A of the present embodiment, the extraction efficiency of the fluorescence Y can be increased.

[0073] (Effect of the First Embodiment) The light source device 30A of this embodiment includes a first light source 41 that emits excitation light E, a wavelength conversion element 50 that converts the excitation light E into fluorescence Y, a first optical member 55 that is disposed between the first light source 41 and the wavelength conversion element 50 and transmits the excitation light E and reflects the fluorescence Y, and a first reflection member 53 that reflects the excitation light E and the fluorescence Y. A first air layer 57 is provided between the first optical member 55 and the wavelength conversion element 50. The wavelength conversion element 50 has a surface 50a on which the excitation light E is incident via the first optical member 55 and the first air layer 57, a back surface 50b facing the opposite side of the surface 50a, and a first end surface 50c and a second end surface 50d that intersect the surface 50a and the back surface 50b and face opposite sides. The first reflection member 53 is disposed in a region on the first end surface 50c side of the first air layer 57. The fluorescence Y emitted from the surface 50a of the wavelength conversion element 50 propagates through the first air layer 57 and is emitted from a region of the second end surface 50d of the first air layer 57.

[0074] As described above, according to the light source device 30A of this embodiment, since a part of the fluorescence Y generated by the wavelength conversion element 50 propagates through the first air layer 57 and is emitted from a region of the second end surface 50d of the first air layer 57, for example, compared with a light source device of a comparative example in which fluorescence propagates inside a translucent member, the loss of the fluorescence Y is small, and the utilization efficiency of the fluorescence Y can be increased.

[0075] The projector 1 of this embodiment includes a light source device 30A, light modulation devices 4R, 4G, 4B that modulate light emitted from the light source device 30A, and a projection optical device 6 that projects the light modulated by the light modulation devices 4R, 4G, 4B. According to this configuration, a projector 1 with high light utilization efficiency can be realized.

[0076] [Second Embodiment] Hereinafter, a second embodiment of the present invention will be described with reference to FIG. 6. The basic configurations of the projector and the light source device in the second embodiment are the same as those in the first embodiment, and the configuration of the wavelength conversion element is different from that in the first embodiment. Therefore, the description of the basic configurations of the projector and the light source device is omitted. FIG. 6 is a cross-sectional view of the light source device 30B according to the second embodiment taken in the XY plane. In FIG. 6, the same reference numerals are given to the components common to the drawings used in the first embodiment, and the description thereof is omitted.

[0077] As shown in FIG. 6, the light source device 30B of the present embodiment includes a support member 29, a housing 31, a first light source 41, a wavelength conversion element 58, a first optical member 55, a first reflection member 53, and a second reflection member (not shown).

[0078] In the light source device 30A of the first embodiment, the wavelength conversion element 50 was made of a transparent phosphor. On the other hand, in the light source device 30B of the present embodiment, the wavelength conversion element 58 is made of a phosphor having light scattering properties. The phosphor having light scattering properties can be realized by dispersing a medium having a refractive index different from that of the transparent phosphor, such as pores or fillers, in the transparent phosphor. The wavelength conversion element 58 has a front surface 58a and a back surface 58b, and a first end surface 58c and a second end surface 58d. Other configurations of the light source device 30B are the same as those of the light source device 30A of the first embodiment.

[0079] (Effect of the Second Embodiment) Also in the present embodiment, the same effect as that of the first embodiment can be obtained, that is, a light source device 30B in which the loss of the fluorescence Y is small when the fluorescence Y propagates through the first air layer 57 and the utilization efficiency of the fluorescence Y is excellent can be realized.

[0080] Furthermore, in the case of the present embodiment, since the wavelength conversion element 58 is made of a phosphor having light scattering properties, the following effects can be obtained. In the case of the first embodiment, since the wavelength conversion element 50 is made of a transparent phosphor, no scattering occurs when the fluorescence Y propagates inside the wavelength conversion element 50, and the traveling direction of the fluorescence Y does not change. Therefore, the fluorescence Y that enters the surface 50a of the wavelength conversion element 50 at an incident angle less than the critical angle repeats total reflection at the same incident angle. In this way, the fluorescence Y propagates while being confined inside the wavelength conversion element 50 and is emitted from the second end surface 50d.

[0081] In contrast, in the case of this embodiment, since the wavelength conversion element 58 is composed of a phosphor having light scattering properties, a lot of scattering occurs when the fluorescence Y propagates inside the wavelength conversion element 58, and the traveling direction of the fluorescence Y changes every time it scatters. Therefore, the fluorescence Y1 reflected by the first optical layer 52 of the first optical member 55 and incident on the wavelength conversion element 58 is scattered by the wavelength conversion element 58 and incident on the first air layer 57 in an angle-converted state, and is emitted from the region on the second end face 58d side of the first air layer 57. A part of the fluorescence Y2 is reflected again by the first optical layer 52 of the first optical member 55 through the first air layer 57, and is then emitted from the region on the second end face 58d side of the first air layer 57. In this way, the fluorescence Y is not confined inside the wavelength conversion element 58, but is taken out into the first air layer 57 and emitted from the region on the second end face 58d side of the first air layer 57. That is, the fluorescence Y propagates inside the first air layer 57 while repeating scattering by the wavelength conversion element 58 and reflection by the first optical member 55, and is emitted from the region on the second end face 58d side of the first air layer 57. As a result, since the loss when the fluorescence Y propagates through the wavelength conversion element 58 is suppressed, the utilization efficiency of the fluorescence Y can be further increased compared to the first embodiment.

[0082] In the case of this embodiment, if substantially all of the fluorescence Y is emitted from the first air layer 57 to the outside, the configuration may be such that only the first air layer 57 is exposed without exposing the wavelength conversion element 58 from the outlet 31k. According to this configuration, the outlet 31k can be made smaller, and the étendue of the fluorescence Y can be reduced.

[0083] [Third Embodiment] Hereinafter, the third embodiment of the present invention will be described with reference to FIGS. 7 to 9. The basic configurations of the projector and the light source device in the third embodiment are the same as those in the first embodiment, and the configuration of the first optical member is different from that in the first embodiment. Therefore, the description of the basic configurations of the projector and the light source device will be omitted. FIG. 7 is a perspective view of the light source device 30C according to the third embodiment. FIG. 8 is a cross-sectional view of the light source device 30C taken along line VIII-VIII in FIG. 7. FIG. 9 is a cross-sectional view of the light source device 30C taken along line IX-IX in FIG. 7. In FIGS. 7 to 9, the same reference numerals are given to the components common to the drawings used in the first embodiment, and the description thereof is omitted.

[0084] As shown in FIGS. 7 to 9, the light source device 30C of the present embodiment includes a support member 29, a housing 31, a first light source 41, a wavelength conversion element 50, a first optical member 55, a first reflecting member 53, and a second reflecting member 54.

[0085] In the light source device 30C of the present embodiment, the first optical member 55 is arranged in the opposite direction to the first optical member 55 of the first embodiment. That is, as shown in FIG. 8, the first optical layer 52 is arranged on the surface of the first light-transmissive member 51 facing the first light source 41.

[0086] In the case of the present embodiment, the behavior of light is different from that of the first embodiment. That is, as shown in FIG. 8, since the first optical layer 52 is provided on the surface of the first light-transmissive member 51 opposite to the first air layer 57, a part of the fluorescence Y propagating through the first air layer 57 enters the first light-transmissive member 51. Among the fluorescence Y incident on the first light-transmissive member 51, the fluorescence Y9 incident at an angle less than the critical angle at the interface between the first light-transmissive member 51 and the first air layer 57 guides light inside the first light-transmissive member 51 while repeating total reflection, and is emitted from the end face 51d. In addition, the fluorescence Y1 reflected by the first light-transmissive member 51 enters the wavelength conversion element 50, is reflected by the back surface 50b of the wavelength conversion element 50, enters the first air layer 57 from the surface 50a of the wavelength conversion element 50, and is emitted from the region on the second end face 50d side of the first air layer 57. In addition, the fluorescence Y2 reflected by the first light-transmissive member 51 enters the wavelength conversion element 50, is reflected by the back surface 50b of the wavelength conversion element 50, and is emitted from the second end face 50d.

[0087] Therefore, as shown in FIG. 7, in a plan view in the X-axis direction which is the normal direction of the second end face 50d of the wavelength conversion element 50, the extraction port 31k overlaps with the first air layer 57, the wavelength conversion element 50, and the first light transmissive member 51. Accordingly, the region on the second end face 50d side of the first air layer 57, the second end face 50d of the wavelength conversion element 50, and the end face 51d of the first light transmissive member 51 are exposed to the outside through the extraction port 31k. Thus, in the light source device 30C of the present embodiment, most of the fluorescence Y is emitted from the region on the second end face 50d side of the first air layer 57, a part of the fluorescence Y is emitted from the second end face 50d of the wavelength conversion element 50, and another part of the fluorescence Y is emitted from the end face 51d of the first light transmissive member 51. Other configurations of the light source device 30C are the same as those of the light source device 30A of the first embodiment.

[0088] (Effect of the Third Embodiment) Also in the present embodiment, the same effect as that of the first embodiment can be obtained, that is, a light source device 30C in which the loss of the fluorescence Y is small when the fluorescence Y propagates through the first air layer 57 and the utilization efficiency of the fluorescence Y is excellent can be realized.

[0089] [Fourth Embodiment] Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS. 10 to 12. The basic configurations of the projector and the light source device of the fourth embodiment are the same as those of the first embodiment, and are different from the first embodiment in that a second light source and a second optical member are added. Therefore, the description of the basic configurations of the projector and the light source device is omitted. FIG. 10 is a perspective view of a light source device 30D according to the fourth embodiment. FIG. 11 is a cross-sectional view of the light source device 30D taken along line XI-XI in FIG. 10. FIG. 12 is a cross-sectional view of the light source device 30D taken along line XII-XII in FIG. 10. In FIGS. 10 to 12, the same reference numerals are given to the components common to the drawings used in the previous embodiments, and the description thereof is omitted.

[0090] As shown in FIGS. 10 to 12, the light source device 30D of the present embodiment includes a support member 29, a housing 71, a first light source 41, a second light source 42, a wavelength conversion element 58, a first optical member 55, a second optical member 59, a first reflection member 53, and a second reflection member 54. In the present embodiment, similar to the second embodiment, the wavelength conversion element 58 is composed of a phosphor having light scattering properties.

[0091] As shown in FIG. 11, in the cross-sectional structure viewed from the Z-axis direction, the configuration on the +Y side from the central axis of the wavelength conversion element 58 is the same as that of the second embodiment. That is, the first light source 41 is disposed to face the surface 58a of the wavelength conversion element 58 and emits excitation light E toward the wavelength conversion element 58. The first optical member 55 is disposed between the first light source 41 and the wavelength conversion element 58. The wavelength conversion element 58 and the first optical member 55 are not in contact with each other, and a first air layer 57 is provided between the wavelength conversion element 58 and the first optical member 55. The excitation light E emitted from the first light source 41 passes through the first optical member 55 and enters the wavelength conversion element 58 through the first air layer 57.

[0092] On the other hand, the configuration on the -Y side from the central axis of the wavelength conversion element 58 is different from that of the second embodiment. As shown in FIG. 12, in the light source device 30D of the present embodiment, the wavelength conversion element 58 is supported by a pair of support portions 72 provided on the housing 71. The back surface 58b of the wavelength conversion element 58 is not in contact with the support member 29.

[0093] The second light source 42 includes a plurality of second light-emitting elements 42a and a substrate 42b. The plurality of second light-emitting elements 42a are mounted on the substrate 42b. The number of the second light-emitting elements 42a is not particularly limited and may be different from the number of the first light-emitting elements 41a. Therefore, the second light source 42 does not necessarily have to have a plurality of second light-emitting elements 42a and may have one second light-emitting element 42a.

[0094] The second light-emitting element 42a emits excitation light E1 in the first wavelength band. The second light-emitting element 42a is composed of the same LED as the first light-emitting element 41a. The second light-emitting element 42a is disposed to face the back surface 58b of the wavelength conversion element 58 and emits the excitation light E1 toward the wavelength conversion element 58. In this way, the second light source 42 emits the excitation light E composed of a plurality of blue excitation light rays E1 toward the wavelength conversion element 58.

[0095] The second optical member 59 is disposed between the second light source 42 and the wavelength conversion element 58. Specifically, the second optical member 59 is disposed on the surface of the support portion 72 facing the second light source 42. The second optical member 59 includes a second light-transmitting member 73 and a second optical layer 74. The second optical layer 74 is provided on the surface of the second light-transmitting member 73 facing the second light source 42 among the two surfaces of the second light-transmitting member 73.

[0096] The second light-transmitting member 73 is composed of the same light-transmitting material as the first light-transmitting member 51. Similar to the first light-transmitting member 51, it is desirable that the thermal conductivity of the second light-transmitting member 73 is greater than the thermal conductivity of the wavelength conversion element 58. According to this configuration, the heat of the wavelength conversion element 58 is efficiently transmitted to the second light-transmitting member 73 through the second air layer 77, so that the temperature rise of the wavelength conversion element 58 can be suppressed. Thereby, the decrease in luminous efficiency accompanying the temperature rise of the wavelength conversion element 58 can be suppressed.

[0097] The second optical layer 74 is disposed between the wavelength conversion element 58 and the second light-transmitting member 73. The second optical layer 74 has the optical property of transmitting the excitation light E and reflecting the fluorescence Y, similar to the first optical layer 52. The second optical layer 74 is provided on the surface of the second light-transmitting member 73 facing the wavelength conversion element 58 among the two surfaces of the second light-transmitting member 73. The second optical layer 74 is composed of a dielectric multilayer film similar to the first optical layer 52.

[0098] A second air layer 77 is provided between the second optical member 59 and the wavelength conversion element 58. That is, the second optical member 59 and the wavelength conversion element 58 are disposed apart from each other, and air exists between the second optical member 59 and the wavelength conversion element 58.

[0099] The first reflection member 53 is disposed on the -X side in the X-axis direction of the wavelength conversion element 58, the first air layer 57, the first optical member 55, the first light source 41, the second air layer 77, the second optical member 59, and the second light source 42. Note that the first reflection member 53 does not have to be provided over all of the above regions, and it may be provided at least in the region on the first end face 58c side of the first air layer 57 and the region on the first end face 58c side of the second air layer 77.

[0100] As shown in FIG. 10, in a state of planar view in the X-axis direction, the outlet 71k overlaps the first air layer 57, the wavelength conversion element 58, and the second air layer 77. Therefore, the region on the second end face 58d side of the first air layer 57, the second end face 58d of the wavelength conversion element 58, and the region on the second end face 58d side of the second air layer 77 are exposed to the outside through the outlet 71k. Other configurations of the light source device 30D are the same as those of the light source device 30B of the second embodiment.

[0101] Hereinafter, the behavior of light in the light source device 30D of the present embodiment will be described. In the light source device 30D of the present embodiment, since the behavior of the excitation light E emitted from the first light source 41 and the fluorescence Y generated by the wavelength conversion element 58 is the same as that of the second embodiment, the behavior of the excitation light E emitted from the second light source 42 will be briefly described.

[0102] The excitation light E emitted from the second light source 42 passes through the second optical member 59 and enters the wavelength conversion element 58 from the back surface 58b through the second air layer 77. Among the fluorescence Y emitted from an arbitrary light-emitting point of the wavelength conversion element 58 toward the -Z side, the fluorescence Y that enters the back surface 58b of the wavelength conversion element 58 at an incident angle less than the critical angle is emitted from the wavelength conversion element 58 and enters the second air layer 77. At this time, the fluorescence Y11 reflected by the second optical layer 74 of the second optical member 59 and incident on the wavelength conversion element 58 enters the second air layer 77 in a state of being scattered and angle-converted by the wavelength conversion element 58, and is emitted from the region on the second end surface 58d side of the second air layer 77. A part of the fluorescence Y21 is reflected again by the second optical layer 74 of the second optical member 59 through the second air layer 77, and is then emitted from the region on the second end surface 58d side of the second air layer 77. On the other hand, the fluorescence Y that travels toward the -X side and reaches the first reflecting member 53 travels toward the +X side after being reflected by the first reflecting member 53, and propagates inside the second air layer 77 while repeating scattering by the wavelength conversion element 58 and reflection by the second optical member 59, and is then emitted from the region on the second end surface 58d side of the second air layer 77.

[0103] Thus, in the light source device 30D of the present embodiment, among the fluorescence Y generated by the wavelength conversion element 58, a part of the fluorescence Y is emitted from the region on the second end surface 58d side of the first air layer 57, and another part of the fluorescence Y is emitted from the region on the second end surface 58d side of the second air layer 77. Therefore, the light source device 30D can efficiently emit the fluorescence Y generated by the wavelength conversion element 58 to the outside from the outlet 71k of the housing 71.

[0104] (Effect of the Fourth Embodiment) The light source device 30D of this embodiment further includes a second light source 42 that is disposed to face the back surface 58b and emits excitation light E, and a second optical member 59 that is disposed between the second light source 42 and the wavelength conversion element 58, transmits the excitation light E, and reflects fluorescence Y. A second air layer 77 is provided between the second optical member 59 and the wavelength conversion element 58. The excitation light E that passes through the second optical member 59 enters the wavelength conversion element 58 from the back surface 58b through the second air layer 77. The first reflection member 53 is disposed in a region on the side of the first end surface 58c of the second air layer 77. The fluorescence Y emitted from the back surface 58b of the wavelength conversion element 58 propagates through the second air layer 77 and is emitted from a region on the side of the second end surface 58d of the second air layer 77.

[0105] Also in this embodiment, the same effect as that of the first embodiment can be obtained, such that the loss of the fluorescence Y is small when the fluorescence Y propagates through the first air layer 57, and a light source device 30D with excellent utilization efficiency of the fluorescence Y can be realized.

[0106] Furthermore, in the case of this embodiment, the excitation light E emitted from the second light source 42 and incident on the back surface 58b of the wavelength conversion element 58 is emitted as fluorescence Y from a light-emitting point near the back surface 58b, and the fluorescence Y is emitted from a region on the side of the second end surface 58d of the second air layer 77 to the external space. Thus, according to this embodiment, since the excitation light E is incident from both the front surface 58a and the back surface 58b of the wavelength conversion element 58, the incident amount of the excitation light E can be increased. Here, as the length of the wavelength conversion element 58 in the X-axis direction increases, it becomes more difficult to extract the fluorescence Y generated in the region opposite to the extraction port 71k. Therefore, when the length of the wavelength conversion element 58 in the X-axis direction is increased to expand the incident area of the excitation light E, there is a possibility that the fluorescence Y cannot be efficiently extracted. On the other hand, in this embodiment, without increasing the length of the wavelength conversion element 58 in the X-axis direction, the fluorescence conversion efficiency can be increased by increasing the incident light amount of the excitation light E, and the fluorescence Y can be efficiently extracted.

[0107] In the light source device 30A of the first embodiment, the fluorescent light Y is returned into the wavelength conversion element 50 by the reflection film formed on the back surface 50b of the wavelength conversion element 50. However, since it is difficult to obtain sufficient film performance for the reflection film formed on the uneven back surface 50b, light absorption is likely to occur. On the other hand, in the case of this embodiment, since the fluorescent light Y emitted from the back surface 58b of the wavelength conversion element 58 is reflected between the second optical layer 74 and the wavelength conversion element 58 and propagated through the second air layer 77, the fluorescent light Y can be efficiently extracted. Further, since the second optical layer 74 is formed on the surface of the second translucent member 73 having a smooth surface, it is easy to improve the film performance, and the second optical layer 74 that efficiently reflects the fluorescent light Y can be formed.

[0108] [Fifth Embodiment] Hereinafter, the fifth embodiment of the present invention will be described with reference to FIG. 13. The basic configuration of the light source device in the fifth embodiment is the same as that in the fourth embodiment, and is different from the fourth embodiment in that a reflection suppression layer is added. Therefore, the description of the basic configuration of the light source device is omitted. FIG. 13 is a cross-sectional view of the light source device 30E of the fifth embodiment. In FIG. 13, the same reference numerals are given to the components common to the drawings used in the fourth embodiment, and the description thereof is omitted.

[0109] As shown in FIG. 13, the light source device 30E of this embodiment includes a support member 29, a housing 71, a first light source 41, a second light source 42, a wavelength conversion element 58, a first optical member 55, a second optical member 59, a first reflection member 53, a second reflection member (not shown), and a reflection suppression layer 79.

[0110] The reflection suppression layer 79 is disposed between the first light source 41 and the wavelength conversion element 58, and between the second light source 42 and the wavelength conversion element 58, respectively. Specifically, the reflection suppression layer 79 is provided on each of the front surface 58a and the back surface 58b of the wavelength conversion element 58. The reflection suppression layer 79 has the property of absorbing the excitation light E, and suppresses the reflection of the excitation light E on the front surface 58a and the back surface 58b of the wavelength conversion element 58. The reflection suppression layer 79 is composed of a general optical film for reflection suppression, a dielectric film, or the like. In addition to the above locations, the reflection suppression layer 79 may be provided on the surface of the first light transmissive member 51 facing the first light source 41, and on the surface of the second light transmissive member 73 facing the second light source 42, etc. Other configurations of the light source device 30E are the same as those of the light source device 30D of the fourth embodiment.

[0111] (Effect of the Fifth Embodiment) Also in this embodiment, the same effect as that of the first embodiment can be obtained, that is, a light source device 30E in which the loss of the fluorescence Y is small and the utilization efficiency of the fluorescence Y is excellent can be realized by the fluorescence Y propagating through the first air layer 57.

[0112] In the case of the above first to fourth embodiments, for example, when the blue excitation light E emitted from the first light source 41 enters the wavelength conversion elements 50 and 58, since the refractive index difference between the first air layer 57 and the wavelength conversion elements 50 and 58 is large, a part of the excitation light E is reflected on the surface of the wavelength conversion elements 50 and 58. Therefore, the amount of the excitation light E that substantially contributes to wavelength conversion decreases, and the wavelength conversion efficiency decreases. Further, the excitation light E reflected on the surface of the wavelength conversion elements 50 and 58 passes through the first optical layer 52, and thus enters the first light emitting element 41a and the members around it and is converted into heat. As a result, problems such as a decrease in the light emission efficiency of the first light emitting element 41a occur.

[0113] In contrast, in the case of this embodiment, since the reflection suppression layer 79 is provided on each of the front surface 58a and the back surface 58b of the wavelength conversion element 58, the amount of the excitation light E that substantially contributes to wavelength conversion increases, and the wavelength conversion efficiency is improved. Also, the reflection of the excitation light E on each surface 58a, 58b of the wavelength conversion element 58 is suppressed, and the temperature rise of the first light source 41 and the second light source 42 is suppressed. Thereby, problems such as a decrease in the luminous efficiency of the first light emitting element 41a and the second light emitting element 42a can be improved. Further, since the reflection of the fluorescence Y incident from the wavelength conversion element 58 to the first air layer 57 and the second air layer 77 is suppressed, the reabsorption of the fluorescence Y inside the wavelength conversion element 58 is reduced, and the extraction efficiency of the fluorescence Y can be increased.

[0114] Note that the technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. In the above embodiment, the first optical member is composed of the first light transmissive member and the first optical layer. Instead of this configuration, it may be composed of a single optical member having the property of transmitting the excitation light and reflecting the fluorescence. That is, the first optical member does not necessarily have the first light transmissive member. Examples of this type of optical member include, for example, a hologram, an optical film with a self-standing design as a single film, and the like.

[0115] Also, as the constituent material of the wavelength conversion element, for example, a composite phosphor containing AlN and Ce:YAG may be used. According to this configuration, as in the above embodiment, even in a configuration where the contact area between the wavelength conversion element, the support member, and the housing is small and many heat dissipation paths cannot be secured, compared with the case where a phosphor of Ce:YAG alone is used, the thermal conductivity of the wavelength conversion element can be increased. Thereby, the cooling efficiency of the wavelength conversion element is increased. Thereby, the maximum amount of the excitation light can be increased, and the maximum output of the fluorescence can be increased.

[0116] In the above embodiment, an example was given in which the wavelength conversion element is composed of a yellow phosphor and converts blue excitation light into yellow fluorescence. However, instead of this configuration, the wavelength conversion element may be composed of a blue phosphor and convert ultraviolet excitation light into blue fluorescence. In this case, the first light emitting element emits excitation light having a peak wavelength of 380 nm in, for example, an ultraviolet wavelength band of 100 nm to 400 nm. The wavelength conversion element is composed of a blue phosphor that converts the ultraviolet light emitted from the first light source into blue fluorescence having a blue wavelength band of, for example, 450 to 495 nm. As the blue phosphor, for example, BaMgAl 10 O 17 :Eu(II) etc. are used. The blue fluorescence propagates inside the first air layer while repeating scattering by the wavelength conversion element and reflection by the first optical member, and is emitted from the region on the fourth surface side of the first air layer.

[0117] In addition, the specific descriptions of the shapes, numbers, arrangements, materials, etc. of the respective components of the light source device and the projector are not limited to the above embodiments and can be appropriately changed. Further, in the above embodiment, an example in which the light source device according to the present invention is mounted on a projector using a liquid crystal panel was shown, but the present invention is not limited to this. The light source device according to the present invention may be applied to a projector using a digital micromirror device as a light modulation device. Further, the projector may not have a plurality of light modulation devices and may have only one light modulation device.

[0118] In the above embodiment, an example in which the light source device of the present invention is applied to a projector was shown, but the present invention is not limited to this. The light source device of the present invention can also be applied to lighting fixtures, automobile headlights, etc.

[0119] [Summary of the present disclosure] Hereinafter, a summary of the present disclosure will be appended.

[0120] (Appended Note 1) A first light source that emits first light in a first wavelength band, A wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band, A first optical member disposed between the first light source and the wavelength conversion element, the first optical member transmitting the first light and reflecting the second light; A first reflecting member that reflects the first light and the second light; Comprising: A first air layer is provided between the first optical member and the wavelength conversion element; The wavelength conversion element has a first surface on which the first light is incident through the first optical member and the first air layer, a second surface facing the opposite side of the first surface, and a third surface and a fourth surface that intersect the first surface and the second surface and face opposite sides of each other; The first reflecting member is disposed in a region on the third surface side of the first air layer; The second light emitted from the first surface of the wavelength conversion element propagates through the first air layer and is emitted from a region on the fourth surface side of the first air layer, a light source device.

[0121] According to the configuration of Supplementary Note 1, since the second light emitted from the first surface of the wavelength conversion element propagates through the first air layer, the loss of the second light is small, and a light source device with excellent utilization efficiency of the second light can be realized.

[0122] (Supplementary Note 2) The first optical member has a first light-transmitting member that transmits the first light, and a first optical layer that transmits the first light and reflects the second light; The first optical layer is disposed on a surface of the first light-transmitting member facing the wavelength conversion element, the light source device according to Supplementary Note 1.

[0123] According to the configuration of Supplementary Note 2, since the second light does not propagate inside the first light-transmitting member, the loss of the second light can be minimized.

[0124] (Supplementary Note 3) The first optical member has a first light-transmitting member that transmits the first light and the second light, and a first optical layer that transmits the first light and reflects the second light; The first optical layer is disposed on a surface of the first light-transmitting member facing the first light source, the light source device according to Supplementary Note 1.

[0125] According to the configuration of Supplementary Note 3, the second light can be extracted to the outside from both the first light-transmissive member and the first air layer.

[0126] (Supplementary Note 4) The light source device according to Supplementary Note 2, wherein the thermal conductivity of the first light-transmissive member is greater than the thermal conductivity of the wavelength conversion element.

[0127] According to the configuration of Supplementary Note 4, since the heat of the wavelength conversion element is efficiently transmitted to the first light-transmissive member through the first air layer, it is possible to suppress a decrease in luminous efficiency accompanying an increase in the temperature of the wavelength conversion element.

[0128] (Supplementary Note 5) The light source device according to Supplementary Note 3, wherein the thermal conductivity of the first light-transmissive member is greater than the thermal conductivity of the wavelength conversion element.

[0129] According to the configuration of Supplementary Note 5, since the heat of the wavelength conversion element is efficiently transmitted to the first light-transmissive member through the first air layer, it is possible to suppress a decrease in luminous efficiency accompanying an increase in the temperature of the wavelength conversion element.

[0130] (Supplementary Note 6) The light source device according to any one of Supplementary Notes 1 to 5, further comprising a reflection suppression layer disposed between the first light source and the wavelength conversion element and suppressing reflection of the first light on the first surface.

[0131] According to the configuration of Supplementary Note 6, the amount of the first light that substantially contributes to wavelength conversion increases, and the wavelength conversion efficiency is improved. Further, since reflection of the first light on the first surface of the wavelength conversion element is suppressed, an increase in the temperature of the first light source due to the reflected light is suppressed. Thereby, a decrease in the luminous efficiency of the first light source is suppressed.

[0132] (Supplementary Note 7) Further comprising a second reflection member that reflects the first light and the second light, The wavelength conversion element has a fifth surface and a sixth surface that intersect each of the first surface, the second surface, the third surface, and the fourth surface and face opposite sides to each other. The light source device according to any one of Appendices 1 to 6, wherein the second reflecting member is disposed in a region on the fifth surface side of the first air layer and a region on the sixth surface side of the first air layer.

[0133] According to the configuration of Appendix 7, the conversion efficiency from the first light to the second light can be increased, and the loss of the second light can be suppressed.

[0134] (Appendix 8) The light source device further includes a support member that supports the wavelength conversion element. The light source device according to any one of Appendices 1 to 7, wherein the second surface is connected to the support member so as to be heat-transferable.

[0135] According to the configuration of Appendix 8, since the heat generated in the wavelength conversion element is transmitted to the support member, the temperature rise of the wavelength conversion element is suppressed, and the wavelength conversion efficiency can be maintained.

[0136] (Appendix 9) The light source device further includes a housing that covers the first optical member and the wavelength conversion element. The housing has an outlet for taking out the second light emitted from a region on the fourth surface side of the first air layer to the outside. The light source device according to Appendix 8, wherein in a state of being viewed in a plan view in the normal direction of the fourth surface of the wavelength conversion element, the outlet overlaps the first air layer and the wavelength conversion element.

[0137] According to the configuration of Appendix 9, the housing can protect the first optical member and the wavelength conversion element, and the second light propagating through the first air layer and the wavelength conversion element can be taken out to the outside through the outlet of the housing.

[0138] (Appendix 10) A second light source that is disposed opposite to the second surface and emits the first light. A second optical member disposed between the second light source and the wavelength conversion element, which transmits the first light and reflects the second light; further comprising; a second air layer is provided between the second optical member and the wavelength conversion element; the first light emitted from the second light source enters the second surface of the wavelength conversion element through the second optical member and the second air layer; the first reflecting member is disposed in a region on the third surface side of the second air layer; the second light emitted from the second surface of the wavelength conversion element propagates through the second air layer and is emitted from a region on the fourth surface side of the second air layer. The light source device according to any one of Appendices 1 to 7.

[0139] According to the configuration of Appendix 10, since a second light source is further provided, the incident light amount of the first light on the wavelength conversion element can be increased. As a result, while increasing the wavelength conversion efficiency, the second light can be efficiently extracted using the second air layer.

[0140] (Appendix 11) further comprising a housing that covers the first optical member, the wavelength conversion element, and the second optical member; the housing has an outlet for extracting to the outside the second light emitted from a region on the fourth surface side of the first air layer and the second light emitted from a region on the fourth surface side of the second air layer; In a state of viewing in a plan view in the normal direction of the fourth surface of the wavelength conversion element, the outlet overlaps the first air layer, the wavelength conversion element, and the second air layer. The light source device according to Appendix 10.

[0141] According to the configuration of Appendix 11, the housing can protect the first optical member, the wavelength conversion element, and the second optical member, and the second light propagating through the first air layer, the wavelength conversion element, and the second air layer can be extracted to the outside through the outlet of the housing.

[0142] (Appendix 12) The wavelength conversion element is composed of a transparent phosphor, and the light source device according to any one of Appendices 1 to 11.

[0143] According to the configuration of Appendix 12, even when a wavelength conversion element made of a transparent phosphor is used, without increasing the size of the wavelength conversion element, by increasing the incident light amount of the first light, while enhancing the conversion efficiency of the second light, the second light can be efficiently extracted to the outside.

[0144] (Appendix 13) The wavelength conversion element is composed of a phosphor having light scattering properties, and the light source device according to any one of Appendices 1 to 11.

[0145] According to the configuration of Appendix 13, the second light generated inside the wavelength conversion element is efficiently emitted to the first air layer and propagates through the first air layer, so that the loss of the second light is suppressed, and the extraction efficiency of the second light can be further enhanced.

[0146] (Appendix 14) The wavelength conversion element is a yellow phosphor, The first light is blue light, The second light is yellow fluorescence, The fluorescence propagates inside the first air layer while repeating scattering by the wavelength conversion element and reflection by the first optical member, and is emitted from a region on the fourth surface side of the first air layer, and the light source device according to Appendix 13.

[0147] According to the configuration of Appendix 14, the yellow fluorescence generated inside the wavelength conversion element can be efficiently extracted to the outside from a region on the fourth surface side of the first air layer.

[0148] (Appendix 15) The wavelength conversion element is a blue phosphor, The first light is ultraviolet light, The second light is blue fluorescence, The fluorescence described above propagates inside the first air layer while repeating scattering by the wavelength conversion element and reflection by the first optical member, and is emitted from the region on the fourth surface side of the first air layer. The light source device according to Supplementary Note 13.

[0149] According to the configuration of Supplementary Note 15, the blue fluorescence generated inside the wavelength conversion element can be efficiently extracted to the outside from the region on the fourth surface side of the first air layer.

[0150] (Supplementary Note 16) A light source device according to any one of Supplementary Notes 1 to 15, An optical modulation device that modulates the light emitted from the light source device, A projection optical device that projects the light modulated by the optical modulation device, A projector comprising the above.

[0151] According to the configuration of Supplementary Note 16, a projector with excellent light utilization efficiency can be realized.

Explanation of Reference Numerals

[0152] 1... Projector, 4B, 4G, 4R... Optical modulation device, 6... Projection optical device, 29... Support member, 30A, 30B, 30C, 30D, 30E... Light source device, 31, 71... Housing, 31k, 71k... Outlet, 41... First light source, 42... Second light source, 50, 58... Wavelength conversion element, 50a, 58a... Surface (first surface), 50b, 58b... Back surface (second surface), 50c, 58c... First end surface (third surface), 50d, 58d... Second end surface (fourth surface), 50e... First side surface (fifth surface), 50f... Second side surface (sixth surface), 51... First light-transmissive member, 52... First optical layer, 53... First reflection member, 54... Second reflection member, 55... First optical member, 57... First air layer, 59... Second optical member, 77... Second air layer, 79... Reflection suppression layer, E... Excitation light (first light), Y... Fluorescence (second light).

Claims

1. A first light source that emits first light in a first wavelength band; A wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band; A first optical member disposed between the first light source and the wavelength conversion element, which transmits the first light and reflects the second light; A first reflecting member that reflects the first light and the second light; Comprising; A first air layer is provided between the first optical member and the wavelength conversion element; The wavelength conversion element has a first surface on which the first light is incident through the first optical member and the first air layer, a second surface facing the opposite side of the first surface, and a third surface and a fourth surface that intersect the first surface and the second surface and face opposite sides of each other; The first reflecting member is disposed in a region on the third surface side of the first air layer; The second light emitted from the first surface of the wavelength conversion element propagates through the first air layer and is emitted from a region on the fourth surface side of the first air layer, a light source device.

2. The first optical member has a first light-transmitting member that transmits the first light and a first optical layer that transmits the first light and reflects the second light; The first optical layer is disposed on a surface of the first light-transmitting member facing the wavelength conversion element. The light source device according to claim 1.

3. The first optical member has a first light-transmitting member that transmits the first light and the second light and a first optical layer that transmits the first light and reflects the second light; The first optical layer is disposed on a surface of the first light-transmitting member facing the first light source. The light source device according to claim 1.

4. The thermal conductivity of the first light-transmitting member is greater than the thermal conductivity of the wavelength conversion element. The light source device according to claim 2.

5. The thermal conductivity of the first light-transmitting member is greater than the thermal conductivity of the wavelength conversion element. The light source device according to claim 3.

6. Further comprising a reflection suppression layer disposed between the first light source and the wavelength conversion element for suppressing reflection of the first light on the first surface. The light source device according to claim 1.

7. Further comprising a second reflecting member that reflects the first light and the second light; The wavelength conversion element has a fifth surface and a sixth surface that intersect each of the first surface, the second surface, the third surface, and the fourth surface and face opposite sides of each other; The light source device according to claim 1, wherein the second reflecting member is disposed in a region on the fifth surface side of the first air layer and a region on the sixth surface side of the first air layer.

8. The light source device further includes a support member that supports the wavelength conversion element, The light source device according to any one of claims 1 to 7, wherein the second surface is connected to the support member so as to be heat-transferable.

9. The light source device further includes a housing that covers the first optical member and the wavelength conversion element, The housing has an outlet for taking out the second light emitted from a region on the fourth surface side of the first air layer to the outside, In a state of planar view in the normal direction of the fourth surface of the wavelength conversion element, the outlet overlaps the first air layer and the wavelength conversion element. The light source device according to claim 8.

10. A second light source disposed opposite to the second surface and emitting the first light; A second optical member disposed between the second light source and the wavelength conversion element, transmitting the first light and reflecting the second light; further comprising A second air layer is provided between the second optical member and the wavelength conversion element, The first light emitted from the second light source enters the second surface of the wavelength conversion element through the second optical member and the second air layer, The first reflecting member is disposed in a region on the third surface side of the second air layer, The second light emitted from the second surface of the wavelength conversion element propagates through the second air layer and is emitted from a region on the fourth surface side of the second air layer. The light source device according to any one of claims 1 to 7.

11. The light source device further includes a housing that covers the first optical member, the wavelength conversion element, and the second optical member, The housing has an outlet for taking out the second light emitted from a region on the fourth surface side of the first air layer and the second light emitted from a region on the fourth surface side of the second air layer to the outside, In a state of planar view in the normal direction of the fourth surface of the wavelength conversion element, the outlet overlaps the first air layer, the wavelength conversion element, and the second air layer. The light source device according to claim 10.

12. The light source device according to any one of claims 1 to 7, wherein the wavelength conversion element is made of a transparent phosphor.

13. The light source device according to any one of claims 1 to 7, wherein the wavelength conversion element is made of a phosphor having light scattering properties.

14. The wavelength conversion element is a yellow phosphor, The first light is blue light, The second light is yellow fluorescence, The fluorescence propagates inside the first air layer while repeating scattering by the wavelength conversion element and reflection by the first optical member, and is emitted from a region on the fourth surface side of the first air layer. The light source device according to claim 13.

15. The wavelength conversion element is a blue phosphor, The first light is ultraviolet light, The second light is blue fluorescence, The fluorescence propagates inside the first air layer while repeating scattering by the wavelength conversion element and reflection by the first optical member, and is emitted from a region on the fourth surface side of the first air layer. The light source device according to claim 13.

16. A light source device according to any one of claims 1 to 7, An optical modulation device that modulates the light emitted from the light source device, A projection optical device that projects the light modulated by the optical modulation device, A projector comprising the above.

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