Light source device and projector

Abstract

To provide a light source device excellent in light utilization efficiency.SOLUTION: A light source device includes a first light source emitting first light, a first wavelength conversion element converting the first light into second light, a first optical layer transmitting the first light and reflecting the second light, a first light guide portion guiding the second light, a second light source emitting third light, a second wavelength conversion element converting the third light into fourth light, a second optical layer transmitting the third light and reflecting the fourth light, and a second light guide portion guiding the fourth light. The first wavelength conversion element has a first surface where the first light enters, and a second surface and a third surface crossing the first surface. The second wavelength conversion element has a fourth surface where the third light enters, and a fifth surface and a sixth surface crossing the fourth surface. The second light travels through the first light guide portion, is emitted from a region of the first light guide portion at the third surface side, and enters a region of the second light guide portion at the fifth surface side. The fourth light and the second light travel through the second light guide portion and are emitted from a region of the second light guide portion at the sixth surface side.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] A light source device for use in a projector has been proposed that utilizes fluorescence emitted from a phosphor when the phosphor is irradiated with excitation light emitted from a light-emitting element. Patent Document 1 listed below discloses a light source device that includes a flat wavelength conversion member containing a phosphor and a light-emitting diode that emits excitation light. In this light source device, excitation light is incident on a larger incident surface of the wavelength conversion member than the other surfaces, and fluorescence is emitted from a smaller exit surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2006 / 054203 Summary of the Invention [Problem to be solved by the invention]

[0004] In the light source device of Patent Document 1, the fluorescence generated inside the wavelength conversion member is totally reflected at the interface between the surface of the wavelength conversion member and the air layer, propagates inside the wavelength conversion member, and is emitted from the emission surface. However, components of the fluorescence that are incident on the interface between the wavelength conversion member and the air layer at an angle less than the critical angle are not totally reflected at the interface and therefore leak from the interface to the outside before reaching the emission surface. This poses a problem of reduced fluorescence utilization efficiency. [Means for solving the problem]

[0005] In order to solve the above problem, 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 first 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 layer that is disposed between the first light source and the first wavelength conversion element and that transmits the first light and reflects the second light, a first light guiding unit that is disposed between the first optical layer and the first wavelength conversion element and that guides the second light converted by the first wavelength conversion element, and a second light guiding unit that converts the second light into a third wavelength band. the first wavelength conversion element includes a second light source that emits third light, a second wavelength conversion element that converts the third light into fourth light in a fourth wavelength band different from the third wavelength band and the second wavelength band, a second optical layer that is disposed between the second light source and the second wavelength conversion element and transmits the third light and reflects the fourth light, a second light guiding section that is disposed between the second optical layer and the second wavelength conversion element and guides the fourth light converted by the second wavelength conversion element, and a first reflecting member that reflects the first light and the second light. The first wavelength conversion element has a first surface onto which the first light is incident via the first optical layer and the first light guiding section, and second and third surfaces that intersect with the first surface and face in opposite directions. The second wavelength conversion element has a fourth surface onto which the third light is incident via the second optical layer and the second light guiding section, and fifth and sixth surfaces that intersect with the fourth surface and face in opposite directions. The first reflecting member is disposed in a region on the second surface side of the first light guiding section. The second light converted by the first wavelength conversion element travels through the first light guiding section, is emitted from the region on the third surface side of the first light guiding section, and is incident on the region on the fifth surface side of the second light guiding section. The fourth light converted by the second wavelength conversion element and the second light emitted from the region on the third surface side travel through the second light guiding section, and are emitted from the region on the sixth surface side of the second light guiding section.

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

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment. [Figure 2] FIG. 1 is a perspective view of a light source device according to a first embodiment. [Figure 3] 3 is a cross-sectional view of the light source device taken along line III-III in FIG. 2. FIG. [Figure 4] 4 is a cross-sectional view of the light source device taken along line IV-IV in FIG. 3. [Figure 5] 4 is a cross-sectional view of the light source device taken along line VV in FIG. 3. [Figure 6] FIG. 10 is a cross-sectional view of a light source device according to a second embodiment. [Figure 7] 10A and 10B are schematic diagrams for explaining the function and effect of the light source device of the second embodiment. [Figure 8] FIG. 10 is a cross-sectional view of a light source device according to a third embodiment. [Figure 9] FIG. 10 is a cross-sectional view of a light source device according to a fourth embodiment. [Figure 10] FIG. 10 is a cross-sectional view of a light source device according to a fifth embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a light source device according to a sixth embodiment. [Figure 12] FIG. 13 is a cross-sectional view of a light source device according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] A first embodiment of the present invention will be described below with reference to the drawings. The projector of this embodiment is an example of a projector that uses a liquid crystal panel as a light modulation device. In the drawings below, the dimensions of some components may be shown on different scales to make them easier to see.

[0009] FIG. 1 is a schematic configuration diagram of a projector 10 according to the present embodiment. 1, the projector 10 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 10 is equipped with three light modulation devices corresponding to red light LR, green light LG, and blue light LB.

[0010] The projector 10 includes an illumination device 20, a color separation light-guiding optical system 200, a red light optical modulation device 400R, a green light optical modulation device 400G, a blue light optical modulation device 400B, a light combining element 500, and a projection optical device 600.

[0011] The illumination device 20 includes a light source device 30A, an integrator optical system 90, a polarization conversion element 93, and a superimposing optical system 94. The illumination device 20 emits white light LW containing red light LR, green light LG, and blue light LB. The specific configuration of the illumination device 20 will be described later.

[0012] In the following drawings, an XYZ Cartesian coordinate system will be used as necessary. The X axis is an axis parallel to the optical axis AX1 of the lighting device 20 and extends along the front-to-rear direction of the projector 10. The Y axis is an axis perpendicular to the X axis and extends along the up-down direction of the projector 10. The Z axis is an axis perpendicular to the X and Y axes and extends along the left-to-right direction of the projector 10. These notations are used to explain the positional relationship of the components of the projector 10 and do not limit the installation posture or direction of the projector 10. The optical axis AX1 of the lighting device 20 is the central axis of the white light LW emitted from the lighting device 20.

[0013] In the following explanation, one of the two directions along the X axis will be referred to as the +X direction, and the opposite direction will be referred to as the -X direction. One of the two directions along the Y axis will be referred to as the +Y direction, and the opposite direction will be referred to as the -Y direction. One of the two directions along the Z axis will be referred to as the +Z direction, and the opposite direction will be referred to as the -Z direction. When referring to two directions along the X axis collectively without distinction, they will be referred to as the X-axis direction. When referring to two directions along the Y axis collectively without distinction, they will be referred to as the Y-axis direction. When referring to two directions along the Z axis collectively without distinction, they will be referred to as the Z-axis direction.

[0014] The color separation and light-guiding optical system 200 includes a first dichroic mirror 210, a second dichroic mirror 220, a first reflecting mirror 230, a second reflecting mirror 240, a third reflecting mirror 250, a first relay lens 260, and a second relay lens 270. The color separation and light-guiding optical system 200 separates white light LW emitted from the illumination device 20 into red light LR, green light LG, and blue light LB, and guides the red light LR to a red light optical modulation device 400R, the green light LG to a green light optical modulation device 400G, and the blue light LB to a blue light optical modulation device 400B.

[0015] A field lens 300R is disposed between the color separation and light-guiding optical system 200 and the red light optical modulator 400R. A field lens 300G is disposed between the color separation and light-guiding optical system 200 and the green light optical modulator 400G. A field lens 300B is disposed between the color separation and light-guiding optical system 200 and the blue light optical modulator 400B. The field lens 300R collimates the chief ray of the red light LR incident on the red light optical modulator 400R. The field lens 300G collimates the chief ray of the green light LG incident on the green light optical modulator 400G. The field lens 300B collimates the chief ray of the blue light LB incident on the blue light optical modulator 400B.

[0016] The first dichroic mirror 210 transmits the red light LR and reflects the green light LG and blue light LB. The second dichroic mirror 220 reflects the green light LG and transmits the blue light LB. The first reflecting mirror 230 reflects the red light LR. The second reflecting mirror 240 and the third reflecting mirror 250 each reflect the blue light LB.

[0017] The red light optical modulator 400R, the green light optical modulator 400G, and the blue light optical modulator 400B each modulate the color light incident thereon in accordance with image information to generate image light. Each of the red light optical modulator 400R, the green light optical modulator 400G, and the blue light optical modulator 400B is composed of a liquid crystal panel.

[0018] Although not shown in the figure, incident-side polarizing plates are arranged between field lens 300R and red light optical modulator 400R, between field lens 300G and green light optical modulator 400G, and between field lens 300B and blue light optical modulator 400B. In addition, exit-side polarizing plates are arranged between red light optical modulator 400R and light combining element 500, between green light optical modulator 400G and light combining element 500, and between blue light optical modulator 400B and light combining element 500. The incident-side polarizing plate and the exit-side polarizing plate only transmit light linearly polarized in a specific direction.

[0019] The light combining element 500 receives the image lights emitted from the red light optical modulation device 400R, the green light optical modulation device 400G, and the blue light optical modulation device 400B, combines the image lights corresponding to the red light LR, the green light LG, and the blue light LB, and emits the combined image light toward the projection optical device 600. The light combining element 500 may be, for example, a cross dichroic prism.

[0020] The projection optical device 600 is composed of a plurality of projection lenses. The projection optical device 600 enlarges and projects the image light combined by the light combining element 500 onto the screen SCR, thereby displaying an image on the screen SCR.

[0021] The configurations of the light source device 30A and the illumination device 20 will be described below. Fig. 2 is a perspective view of light source device 30A of this embodiment. Fig. 3 is a cross-sectional view of light source device 30A taken along line III-III in Fig. 2. Fig. 4 is a cross-sectional view of light source device 30A taken along line IV-IV in Fig. 3. Fig. 5 is a cross-sectional view of light source device 30A taken along line VV in Fig. 3.

[0022] As shown in Figures 2 to 5, the light source device 30A of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 51, a first optical layer 61, a first light guiding section 71, a second light source 42, a second wavelength conversion element 52, a second optical layer 62, a second light guiding section 72, a first reflecting member 81, a second reflecting member 82, a third reflecting member 83, and a fourth optical layer 64.

[0023] The housing 31 constitutes the exterior of the light source device 30A. The housing 31 accommodates the first light source 41, the first optical layer 61, the first light guiding section 71, the first wavelength conversion element 51, the second light source 42, the second optical layer 62, the second light guiding section 72, the second wavelength conversion element 52, the first reflecting member 81, the second reflecting member 82, the third reflecting member 83, and the fourth optical layer 64. The housing 31 is composed of a bottom plate 32 and a lid 33. The bottom plate 32 has a substantially plate-like shape. The lid 33 has a box-like shape with one side open, and includes a top wall 33a, a first side wall 33c, a second side wall 33d, a third side wall 33e, a fourth side wall 33f, and an outlet 33k.

[0024] The bottom plate portion 32 is disposed along the XZ plane and supports one of a pair of first light source 41 and second light source 42, i.e., the first light source 41 and the second light source 42. The bottom plate portion 32 has a base portion 32a and a frame portion 32b. The base portion 32a is a plate-shaped member that forms the main body of the bottom plate portion 32 and extends long in the X-axis direction. The frame portion 32b is formed integrally with the base portion 32a and is provided on a surface located on the +Y side of the base portion 32a. The bottom plate portion 32 has recesses that accommodate the first light source 41 and the second light source 42.

[0025] The bottom plate portion 32 is connected to one of the first light source 41 and the second light source 42 in a manner that allows heat transfer. For this reason, it is desirable that the bottom plate portion 32 be made of a material that has a predetermined strength and high thermal conductivity. Therefore, it is desirable that the material of the bottom plate portion 32 be a metal such as aluminum or stainless steel, and in particular, an aluminum alloy such as a 6061 series aluminum alloy.

[0026] In the cover 33, the top wall 33a is disposed along the XZ plane. The first side wall 33c and the second side wall 33d intersect with the X axis along the longitudinal direction of the light source device 30A and are positioned on opposite sides of each other in the X axis direction. The first side wall 33c is positioned on the -X side, which is one side in the X axis direction. The second side wall 33d is positioned on the +X side, which is the other side in the X axis direction. The third side wall 33e and the fourth side wall 33f are positioned on opposite sides of each other in the Z axis direction, which intersects with the longitudinal direction of the light source device 30A. In this embodiment, the third side wall 33e is positioned on the +Z side, which is one side in the Z axis direction. The fourth side wall 33f is positioned on the -Z side, which is the other side in the Z axis direction.

[0027] The lid 33 accommodates the other of the pair of first and second light sources 41 and 42, the first optical layer 61, the first light guiding section 71, the first wavelength conversion element 51, the second optical layer 62, the second light guiding section 72, the second wavelength conversion element 52, the first reflecting member 81, the second reflecting member 82, the third reflecting member 83, and the fourth optical layer 64. The top wall 33a is connected to the other of the first and second light sources 41 and 42 in a heat-transferable manner. The third side wall 33e and the fourth side wall 33f are connected to the first and second wavelength conversion elements 51 and 52 via the second reflecting member 82 and the third reflecting member 83 in a heat-transferable manner. For this reason, like the bottom plate 32, the lid 33 is desirably made of a material having a predetermined strength and high thermal conductivity. Therefore, the material of the lid 33 is preferably a metal such as aluminum or stainless steel, similar to the bottom plate, and in particular an aluminum alloy such as 6061 series.

[0028] According to this configuration, heat from the first wavelength conversion element 51 and the second wavelength conversion element 52 is released to the outside through the lid 33, thereby suppressing a rise in temperature of the first wavelength conversion element 51 and the second wavelength conversion element 52. As a result, a decrease in conversion efficiency due to a rise in temperature of the first wavelength conversion element 51 and the second wavelength conversion element 52 can be suppressed.

[0029] As shown in Fig. 3, the first reflecting member 81 is disposed on the first side wall 33c of the lid 33. As shown in Fig. 4, the second reflecting member 82 is disposed on the third side wall 33e and the fourth side wall 33f of the lid 33. As shown in Fig. 5, the third reflecting member 83 is disposed on the third side wall 33e and the fourth side wall 33f of the lid 33. The extraction outlet 33k is provided in the second side wall 33d of the lid 33. The extraction outlet 33k is an opening for extracting the yellow fluorescence Y and the blue fluorescence B emitted from the second light guiding unit 72 and the second wavelength conversion element 52 to the outside.

[0030] The lid 33 is disposed so as to abut against the base portion 32a of the bottom plate portion 32. The lid 33 and the bottom plate portion 32 are fixed to each other via fixing members such as adhesive or screws (not shown). In this manner, in the light source device 30A, the components of the first light source 41, the first optical layer 61, the first light guide portion 71, the first wavelength conversion element 51, the second light source 42, the second optical layer 62, the second light guide portion 72, the second wavelength conversion element 52, the first reflecting member 81, the second reflecting member 82, the third reflecting member 83, and the fourth optical layer 64 are housed in a space surrounded by the housing 31. This makes it possible to prevent foreign matter such as dust from adhering to the components.

[0031] The first light source 41 has a plurality of first light-emitting elements 411. The plurality of first light-emitting elements 411 are mounted on the bottom plate 32 and the top wall 33a of the housing 31, respectively. The number of first light-emitting elements 411 included in the first light source is not particularly limited. The first light-emitting elements 411 emit first excitation light rays in a first wavelength band. The first light-emitting elements 411 are configured, for example, by light-emitting diodes (LEDs). The first light-emitting elements 411 are arranged opposite the first wavelength conversion element 51 and emit first excitation light rays toward the first wavelength conversion element 51. The first wavelength band is, for example, a wavelength band from purple to blue of 400 nm to 480 nm, and has a center wavelength of, for example, 455 nm. The plurality of first light-emitting elements 411 are arranged along the X-axis direction, which is the longitudinal direction of the first wavelength conversion element 51. In this way, the first light source 41 emits the first excitation light E1 of the first wavelength band, which is made up of a plurality of blue first excitation light rays, toward the first wavelength conversion element 51. The first excitation light E1 of this embodiment corresponds to the first light in the claims.

[0032] The first wavelength conversion element 51 has a columnar shape extending along the X-axis and has six faces. The sides of the first wavelength conversion element 51 extending along the X-axis are longer than the sides extending along the Y-axis and the Z-axis. The X-axis direction corresponds to the longitudinal direction of the first wavelength conversion element 51. The Y-axis direction is a direction parallel to the shortest side of the first wavelength conversion element 51. The length of the sides along the Y-axis is shorter than the length of the sides along the Z-axis. That is, the cross-sectional shape of the first wavelength conversion element 51 cut along a plane along the YZ plane is rectangular, as shown in FIG. 4.

[0033] The first wavelength conversion element 51 has a front surface 51a, a back surface 51b, a first end surface 51c, a second end surface 51d, a first side surface 51e, and a second side surface 51f. The front surface 51a and the back surface 51b intersect with the Y axis and face opposite sides along the Y axis. In this embodiment, the front surface 51a is located on the +Y side, which is one side in the Y axis direction. The back surface 51b is located on the -Y side, which is the other side in the Y axis direction. First excitation light E1 is incident on the front surface 51a from the first light source 41 arranged on the top wall 33a via the first optical layer 61 and the first light guide 71. First excitation light E1 is incident on the back surface 51b from the first light source 41 arranged on the bottom plate 32 via the first optical layer 61 and the first light guide 71. The front surface 51a in this embodiment corresponds to the first surface of the claims.

[0034] As shown in FIG. 3, the first end face 51c and the second end face 51d intersect the front face 51a and the back face 51b and face opposite each other in the X-axis direction along the longitudinal direction of the first wavelength conversion element 51. In this embodiment, the first end face 51c is located on the -X side, which is one side in the X-axis direction. The second end face 51d is located on the +X side, which is the other side in the X-axis direction. The first end face 51c of this embodiment corresponds to a second face in the claims. The second end face 51d of this embodiment corresponds to a third face in the claims.

[0035] As shown in FIG. 4, the first side surface 51e and the second side surface 51f intersect the front surface 51a, the back surface 51b, the first end surface 51c, and the second end surface 51d, and face opposite each other in the Z-axis direction. In this embodiment, the first side surface 51e is located on one side, the +Z side, in the Z-axis direction, and the second side surface 51f is located on the other side, the -Z side, in the Z-axis direction. The first side surface 51e of this embodiment corresponds to face 7 of the claims. The second side surface 51f of this embodiment corresponds to face 8 of the claims.

[0036] The first wavelength conversion element 51 contains at least a yellow phosphor and converts the first excitation light E1 of a first wavelength band emitted from the first light source 41 into yellow fluorescence Y of a second wavelength band different from the first wavelength band. As will be described in detail later, a portion of the yellow fluorescence Y generated inside the first wavelength conversion element 51 is emitted from the front surface 51a and the back surface 51b to the first light guiding section 71.

[0037] The first wavelength conversion element 51 includes a ceramic phosphor made of a polycrystalline phosphor that converts the wavelength of the first excitation light E1 into yellow fluorescence Y. The first wavelength conversion element 51 of this embodiment is made of a phosphor that does not have light-scattering properties, that is, a so-called transparent phosphor. The second wavelength band of the yellow fluorescence Y is, for example, a yellow wavelength band of 490 to 750 nm. The center wavelength of the second wavelength band is, for example, 550 nm. In other words, the fluorescence Y is yellow fluorescence containing a red light component and a green light component. The yellow fluorescence Y of this embodiment corresponds to the second light in the claims.

[0038] The first wavelength conversion element 51 may include a single crystal phosphor instead of a polycrystalline phosphor. Alternatively, the first wavelength conversion element 51 may be made of fluorescent glass. Alternatively, the first wavelength conversion element 51 may be made of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin. The first wavelength conversion element 51 made of such a material converts the first excitation light E1 into yellow fluorescence Y.

[0039] Specifically, the material of the first wavelength conversion element 51 includes, for example, an yttrium-aluminum-garnet (YAG) phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, the material of the first wavelength conversion element 51 may be a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and causing a solid-phase reaction, Y-Al-O amorphous particles obtained by a wet method such as a coprecipitation method or a sol-gel method, or YAG particles obtained by a gas-phase method such as a spray-drying method, a flame pyrolysis method, or a thermal plasma method.

[0040] The first optical layer 61 is disposed between the first light source 41 and the first wavelength conversion element 51. Specifically, the first optical layer 61 is disposed between the first light source 41 and the first wavelength conversion element 51 on the bottom plate portion 32 side, and between the first light source 41 and the first wavelength conversion element 51 on the top wall portion 33a side. The first optical layer 61 has the optical property of transmitting the first excitation light E1 and reflecting the yellow fluorescence Y. The first optical layer 61 is formed of, for example, a dielectric multilayer film. The first optical layer 61 is disposed on a surface of a first light-transmissive member 73 (described later) that faces the first light source 41.

[0041] The first light guiding section 71 is disposed between the first optical layer 61 and the first wavelength conversion element 51. Specifically, the first light guiding section 71 is disposed between the first optical layer 61 and the first wavelength conversion element 51 on the side closer to the bottom plate 32, and between the first optical layer 61 and the first wavelength conversion element 51 on the side closer to the top wall 33a. The first light guiding section 71 guides the yellow fluorescence Y converted by the first wavelength conversion element 51. In the present embodiment, a first light-transmissive member 73 that transmits the first excitation light E1 and the yellow fluorescence Y is disposed in the first light guiding section 71. The first light-transmissive member 73 is bonded to the front surface 51a and the back surface 51b of the first wavelength conversion element 51 with an optical adhesive.

[0042] The first light-transmissive member 73 is made of a light-transmissive material such as borosilicate glass such as BK7, quartz, synthetic quartz, crystal, SiC, GaN, MgO, YAG, sapphire, or diamond. As described above, the first light-transmissive member 73 needs to be made of a material that can transmit the first excitation light E1 and the yellow fluorescence Y. The first light-transmissive member 73 has a plate-like shape extending along the X-axis. As shown in FIG. 4 , the first light-transmissive member 73 has a rectangular cross-sectional shape when cut along a plane along the YZ plane, and extends elongated in the X-axis direction.

[0043] The thermal conductivity of the first light-transmissive member 73 is desirably greater than the thermal conductivity of the first wavelength conversion element 51. Materials for the first light-transmissive member 73 that satisfy this relationship include, for example, SiC, GaN, MgO, YAG, sapphire, and diamond. With this configuration, heat from the first wavelength conversion element 51 is efficiently conducted to the first light-transmissive member 73, thereby suppressing a temperature rise in the first wavelength conversion element 51. This makes it possible to suppress a decrease in conversion efficiency due to a temperature rise in the first wavelength conversion element 51.

[0044] 3, the first reflecting member 81 is disposed on the −X side of the first wavelength conversion element 51, the first light guiding unit 71, the first optical layer 61, and the first light source 41. Specifically, the first reflecting member 81 is provided on the first side wall 33c of the housing 31 so as to face the first end surface 51c of the first wavelength conversion element 51, the region on the first end surface 51c side of the first light guiding unit 71, the end face on the first end surface 51c side of the first optical layer 61, and the region on the first end surface 51c side of the first light source 41. Note that the first reflecting member 81 does not necessarily have to be provided over the entire region, but only needs to be provided in at least the region on the first end surface 51c side of the first light guiding unit 71.

[0045] The first reflecting member 81 reflects the yellow fluorescence Y that has propagated through the first light guiding unit 71 and the first wavelength conversion element 51 and reached the first reflecting member 81. The first reflecting member 81 also reflects the first excitation light E1 that has been reflected by the surface 51a of the first wavelength conversion element 51, propagated through the first light guiding unit 71, and reached the first reflecting member 81. That is, the first reflecting member 81 reflects the yellow fluorescence Y and the first excitation light E1. The first reflecting member 81 is made of, for example, a metal film, a dielectric multilayer film, a scattering member made of barium sulfate, or the like.

[0046] 4, a pair of second reflecting members 82 are arranged on both sides in the Z-axis direction of the first optical layer 61, the first light guiding section 71, and the first wavelength conversion element 51. One of the second reflecting members 82 is arranged on the third side wall 33e of the housing 31 so as to face the first side surface 51e side of the first wavelength conversion element 51 and the area on the first side surface 51e side of the first light guiding section 71. The other second reflecting member 82 is arranged on the fourth side wall 33f of the housing 31 so as to face the second side surface 51f side of the first wavelength conversion element 51 and the area on the second side surface 51f side of the first light guiding section 71.

[0047] The second reflecting member 82 reflects the yellow fluorescence Y and the first excitation light E1. Therefore, the second reflecting member 82 reflects the first excitation light E1 that is reflected by the surface 51a of the first wavelength conversion element 51, enters the first light guiding section 71, and reaches the second reflecting member 82, and causes it to enter the first wavelength conversion element 51. This increases the efficiency of converting the first excitation light E1 into yellow fluorescence Y. The second reflecting member 82 also reflects the yellow fluorescence Y that is emitted from the first wavelength conversion element 51, enters the first light guiding section 71, and reaches the second reflecting member 82, as well as the yellow fluorescence Y that is guided inside the first wavelength conversion element 51 and reaches the second reflecting member 82. This reduces loss of the yellow fluorescence Y. The second reflecting member 82 is formed of, for example, a metal film, a dielectric multilayer film, a scattering member, or the like.

[0048] As shown in FIG. 3 , the second light source 42 has a plurality of second light-emitting elements 421. The second light-emitting elements 421 are mounted on the bottom plate 32 and the top wall 33a of the housing 31 in regions on the +X side of the first light-emitting elements 411. The number of second light-emitting elements 421 is not particularly limited. The second light-emitting elements 421 emit second excitation light rays in a third wavelength band. The second light-emitting elements 421 are configured, for example, with LEDs. The second light-emitting elements 421 are disposed opposite the second wavelength conversion element 52 and emit second excitation light rays toward the second wavelength conversion element 52. The third wavelength band is, for example, an ultraviolet wavelength band, and the center wavelength is, for example, 380 nm. The second light-emitting elements 421 are disposed along the X-axis direction, which is the longitudinal direction of the second wavelength conversion element 52. In this manner, the second light source 42 emits second excitation light E2 in the third wavelength band, which is composed of a plurality of ultraviolet second excitation light rays, toward the second wavelength conversion element 52. The second excitation light E2 in this embodiment corresponds to the third light in the claims.

[0049] The second wavelength conversion element 52 is disposed on the +X side of the first wavelength conversion element 51. The second wavelength conversion element 52 has a columnar shape extending along the X axis and has six faces. The sides of the second wavelength conversion element 52 extending along the X axis are longer than the sides extending along the Y axis and the Z axis. The X axis direction corresponds to the longitudinal direction of the second wavelength conversion element 52. The Y axis direction is a direction parallel to the shortest side of the sides of the second wavelength conversion element 52. The length of the sides along the Y axis is shorter than the length of the sides along the Z axis. That is, the cross-sectional shape of the second wavelength conversion element 52 cut along a plane along the YZ plane is rectangular, as shown in FIG. 5.

[0050] The second wavelength conversion element 52 has a front surface 52a, a back surface 52b, a first end surface 52c, a second end surface 52d, a first side surface 52e, and a second side surface 52f. The front surface 52a and the back surface 52b intersect the Y axis and face opposite sides along the Y axis. In this embodiment, the front surface 52a is located on the +Y side, which is one side in the Y axis direction. The back surface 52b is located on the -Y side, which is the other side in the Y axis direction. The second excitation light E2 is incident on the front surface 52a from the second light source 42 arranged on the top wall 33a via the second optical layer 62 and the second light guide 72. The second excitation light E2 is incident on the back surface 52b from the second light source 42 arranged on the bottom plate 32 via the second optical layer 62 and the second light guide 72. The front surface 52a in this embodiment corresponds to the fourth surface of the claims.

[0051] As shown in FIG. 3, the first end face 52c and the second end face 52d intersect the front surface 52a and the back surface 52b and face opposite each other in the X-axis direction along the longitudinal direction of the second wavelength conversion element 52. In this embodiment, the first end face 52c is located on the -X side, which is one side in the X-axis direction, and faces the second end face 51d of the first wavelength conversion element 51. The second end face 52d is located on the +X side, which is the other side in the X-axis direction. The first end face 52c of this embodiment corresponds to face 5 in the claims. The second end face 52d of this embodiment corresponds to face 6 in the claims.

[0052] As shown in FIG. 5, the first side surface 52e and the second side surface 52f intersect the front surface 52a, the back surface 52b, the first end surface 52c, and the second end surface 52d, and face opposite each other in the Z-axis direction. In this embodiment, the first side surface 52e is located on one side, the +Z side, in the Z-axis direction, and the second side surface 52f is located on the other side, the -Z side, in the Z-axis direction. The first side surface 52e in this embodiment corresponds to face 9 of the claims. The second side surface 52f in this embodiment corresponds to face 10 of the claims.

[0053] The second wavelength conversion element 52 contains at least a blue phosphor and converts the second excitation light E2 in the third wavelength band emitted from the plurality of second light emitting elements 421 of the second light source 42 into blue fluorescence B in a fourth wavelength band different from the third wavelength band and the second wavelength band. As will be described in detail later, a portion of the blue fluorescence B generated inside the second wavelength conversion element 52 is emitted from the front surface 52a and the back surface 52b to the second light guiding section 72.

[0054] The second wavelength conversion element 52 includes a phosphor that converts the wavelength of the second excitation light E2 into blue fluorescence B. An example of the phosphor is (Sr,Ba). 10 (PO4)6Cl2:Eu 2+ (SBCA). The second wavelength conversion element 52 of this embodiment is made of a phosphor that does not have light scattering properties, that is, a so-called transparent phosphor. The fourth wavelength band of the blue fluorescence B is, for example, a blue wavelength band of 430 to 490 nm. The center wavelength of the fourth wavelength band is, for example, 460 nm. The blue fluorescence B of this embodiment corresponds to the fourth light in the claims. Note that the material of the second wavelength conversion element 52 is BaMgAl 10 O 17 :Eu(II) and the like may also be used.

[0055] The second optical layer 62 is disposed between the second light source 42 and the second wavelength conversion element 52. Specifically, the second optical layer 62 is disposed between the second light source 42 and the second wavelength conversion element 52 on the bottom plate portion 32 side, and between the second light source 42 and the second wavelength conversion element 52 on the top wall portion 33a side. The second optical layer 62 has the optical property of transmitting the second excitation light E2 and reflecting the blue fluorescence B. The second optical layer 62 is formed of, for example, a dielectric multilayer film. The second optical layer 62 is disposed on a surface of a second light-transmissive member 74 (described later) that faces the second light source 42.

[0056] In the present embodiment, the second optical layer 62 transmits the second excitation light E2 and reflects the blue fluorescence B, and also reflects the yellow fluorescence Y. Therefore, the yellow fluorescence Y converted by the first wavelength conversion element 51 is reflected by the second optical layer 62 while propagating inside the second light guiding section 72. This prevents the yellow fluorescence Y from being emitted from the second light guiding section 72 toward the second light source 42 and being lost, and makes it possible to maintain the utilization efficiency of the yellow fluorescence Y.

[0057] The second light guiding section 72 is disposed between the second optical layer 62 and the second wavelength conversion element 52. Specifically, the second light guiding section 72 is disposed between the second optical layer 62 and the second wavelength conversion element 52 on the side closer to the bottom plate 32, and between the second optical layer 62 and the second wavelength conversion element 52 on the side closer to the top wall 33a. The second light guiding section 72 guides the blue fluorescence B converted by the second wavelength conversion element 52 and the yellow fluorescence Y converted by the first wavelength conversion element 51. In this embodiment, a second light-transmissive member 74 that transmits the second excitation light E2, the blue fluorescence B, and the yellow fluorescence Y is disposed in the second light guiding section 72. The second light-transmissive member 74 is bonded to the front surface 52a and the back surface 52b of the second wavelength conversion element 52 with an optical adhesive.

[0058] The second light-transmissive member 74 is made of a light-transmissive material such as borosilicate glass (e.g., BK7), quartz, synthetic quartz, crystal, SiC, GaN, MgO, YAG, sapphire, or diamond. As described above, the second light-transmissive member 74 must be made of a material that can transmit the second excitation light E2, the blue fluorescence B, and the yellow fluorescence Y. The second light-transmissive member 74 has a plate-like shape extending along the X-axis. As shown in FIG. 5 , the second light-transmissive member 74 has a rectangular cross-section taken along the YZ plane and extends elongated in the X-axis direction. The material of the second light-transmissive member 74 may be the same as or different from the material of the first light-transmissive member 73.

[0059] The thermal conductivity of the second light-transmissive member 74 is desirably greater than the thermal conductivity of the second wavelength conversion element 52. Materials for the second light-transmissive member 74 that satisfy this relationship include, for example, SiC, GaN, MgO, YAG, sapphire, and diamond. With this configuration, heat from the second wavelength conversion element 52 is efficiently conducted to the second light-transmissive member 74, thereby suppressing a temperature rise in the second wavelength conversion element 52. This makes it possible to suppress a decrease in conversion efficiency due to a temperature rise in the second wavelength conversion element 52.

[0060] 5, a pair of third reflecting members 83 are disposed on both sides in the Z-axis direction of the second optical layer 62, the second light guiding section 72, and the second wavelength conversion element 52. One of the third reflecting members 83 is disposed on the third side wall 33e of the housing 31 so as to face the first side surface 52e side of the second wavelength conversion element 52 and the area on the first side surface 52e side of the second light guiding section 72. The other third reflecting member 83 is disposed on the fourth side wall 33f of the housing 31 so as to face the second side surface 52f side of the second wavelength conversion element 52 and the area on the second side surface 52f side of the second light guiding section 72.

[0061] The third reflecting member 83 reflects the blue fluorescence B and the second excitation light E2. Therefore, the third reflecting member 83 reflects the second excitation light E2 that is reflected by the surface 52a of the second wavelength conversion element 52, enters the second light guiding section 72, and reaches the third reflecting member 83, and then reflects it to the second wavelength conversion element 52. This improves the conversion efficiency of the second excitation light E2 to blue fluorescence B. Furthermore, the third reflecting member 83 reflects the blue fluorescence B that is emitted from the second wavelength conversion element 52, enters the second light guiding section 72, and reaches the third reflecting member 83, as well as the blue fluorescence B that is guided inside the second wavelength conversion element 52 and reaches the third reflecting member 83. This reduces loss of the blue fluorescence B. The third reflecting member 83 is made of, for example, a metal film, a dielectric multilayer film, a scattering member, or the like. Furthermore, the third reflecting member 83 also reflects the yellow fluorescence Y converted by the first wavelength conversion element 51. This also makes it possible to suppress the loss of yellow fluorescence Y.

[0062] 3, the fourth optical layer 64 is disposed between the first light guiding unit 71 and the second light guiding unit 72. Specifically, the fourth optical layer 64 is disposed between the second end face 51d of the first wavelength conversion element 51 and the first end face 52c of the second wavelength conversion element 52, between a region on the second end face 51d side of the first light guiding unit 71 and a region on the first end face 52c side of the second light guiding unit 72, between a region on the second end face 51d side of the first optical layer 61 and a region on the first end face 52c side of the second optical layer 62, and between the first light source 41 and the second light source 42. Note that the fourth optical layer 64 does not necessarily have to be disposed over the entire region described above, but only needs to be disposed at least between a region on the second end face 51d side of the first light guiding unit 71 and a region on the first end face 52c side of the second light guiding unit 72. The fourth optical layer 64 has the optical property of transmitting the yellow fluorescence Y and reflecting the second excitation light E2 and the blue fluorescence B. The fourth optical layer 64 is made of a dielectric multilayer film formed on one surface of a translucent member. The fourth optical layer 64 of this embodiment is formed on the surface of a translucent member (not shown) and fixed to the housing 31.

[0063] 1, an integrator optical system 90 is provided on the light emission side of the light source device 30A. The integrator optical system 90 has a first lens array 91 and a second lens array 92. The integrator optical system 90, together with a superimposing optical system 94, functions as a uniform illumination optical system that uniformizes the intensity distribution of the white light LW emitted from the light source device 30A in each of the light modulation devices 400R, 400G, and 400B, which are the illuminated areas. The white light LW emitted from the light source device 30A is incident on the first lens array 91.

[0064] The first lens array 91 has a plurality of first lenses 91a. The plurality of first lenses 91a are arranged in a matrix in a plane parallel to the YZ plane orthogonal to the optical axis AX1 of the illumination device 20. The plurality of first lenses 91a split the white light LW emitted from the light source device 30A into a plurality of partial light beams. The shape of each of the first lenses 91a is rectangular, which is approximately similar to the shape of the image formation areas of the light modulation devices 400R, 400G, and 400B. This allows each of the partial light beams emitted from the first lens array 91 to efficiently enter the image formation areas of the light modulation devices 400R, 400G, and 400B.

[0065] The white light LW emitted from the first lens array 91 travels toward the second lens array 92. The second lens array 92 is disposed opposite the first lens array 91. The second lens array 92 has a plurality of second lenses 92a corresponding to the plurality of first lenses 91a of the first lens array 91. The second lens array 92, together with the superimposing optical system 94, forms each of the images of the plurality of first lenses 91a of the first lens array 91 near the image forming areas of the light modulation devices 400R, 400G, and 400B. The plurality of second lenses 92a are arranged in a matrix in a plane parallel to the YZ plane that is perpendicular to the optical axis AX1 of the illumination device 20. The superimposing optical system 94 is composed of a single convex lens.

[0066] In this embodiment, the first lenses 91a of the first lens array 91 and the second lenses 92a of the second lens array 92 have the same size, but may have different sizes. Also, in this embodiment, the first lenses 91a of the first lens array 91 and the second lenses 92a of the second lens array 92 are arranged so that their optical axes coincide with each other, but they may be arranged eccentrically with each other.

[0067] The polarization conversion element 93 converts the polarization direction of the white light LW emitted from the second lens array 92. Specifically, the polarization conversion element 93 converts each partial beam of the white light LW split by the first lens array 91 and emitted from the second lens array 92 into linearly polarized light. The polarization conversion element 93 has a polarization separation layer (not shown), a reflection layer (not shown), and a phase difference layer (not shown). The polarization separation layer transmits one linearly polarized component of the polarization components contained in the white light LW emitted from the light source device 30A as 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 phase difference layer converts the other linearly polarized component reflected by the reflection layer into one linearly polarized component.

[0068] The behavior of light in the light source device 30A of this embodiment will be described below. 3, in the light source device 30A, the first excitation light E1 emitted from the first light source 41 passes through the first optical layer 61 and the first translucent member 73 and enters the first wavelength conversion element 51. Note that a part of the first excitation light E1 is backscattered by the front surface 51a and the back surface of the first wavelength conversion element 51 and proceeds toward the first light source 41, but is reflected by the first optical layer 61 or the first translucent member 73 and enters the first wavelength conversion element 51.

[0069] When the first excitation light E1 is incident on the first wavelength conversion element 51, the phosphor contained inside the first wavelength conversion element 51 is excited, and yellow fluorescence Y is emitted from any light-emitting point. At this time, the first excitation light E1 incident on the phosphor is diffused and propagates over an area wider than the incident area, thereby expanding the width of the emission area of ​​the yellow fluorescence Y, resulting in so-called bleeding of the yellow fluorescence Y.

[0070] The yellow fluorescence Y incident on the front surface 51a and the back surface 51b of the first wavelength conversion element 51 at an incident angle less than the critical angle is emitted from the first wavelength conversion element 51, enters the first translucent member 73, and propagates inside the first translucent member 73. At this time, the fluorescence Y1 traveling toward the +X side is reflected by the first optical layer 61 and enters the first wavelength conversion element 51 again. In the present embodiment, since the first wavelength conversion element 51 is made of a transparent phosphor, the yellow fluorescence Y is not scattered inside the first wavelength conversion element 51, and the traveling direction of the yellow fluorescence Y1 does not change inside the first wavelength conversion element 51. Therefore, the yellow fluorescence Y1 enters the first translucent member 73 from the back surface 51b of the first wavelength conversion element 51 and exits from a region on the second end surface 51d side of the first translucent member 73.

[0071] Of the yellow fluorescence Y emitted from the first wavelength conversion element 51, the yellow fluorescence Y0 that is incident perpendicularly on the first optical layer 61 is repeatedly reflected between the two first optical layers 61 because the first wavelength conversion element 51 is made of a transparent phosphor and the direction of travel of the yellow fluorescence Y0 does not change inside the first wavelength conversion element 51.

[0072] The yellow fluorescence Y2 incident on the surface 51a and the back surface 51b of the first wavelength conversion element 51 at an incident angle equal to or greater than the critical angle is totally reflected by the surface 51a and the back surface 51b of the first wavelength conversion element 51. At this time, in the case of this embodiment, the first wavelength conversion element 51 is made of a transparent phosphor, and the traveling direction of the yellow fluorescence Y2 does not change inside the first wavelength conversion element 51, so the incident angle of the yellow fluorescence Y2 on the surface 51a and the back surface 51b of the first wavelength conversion element 51 also does not change. Therefore, the yellow fluorescence Y2 is repeatedly totally reflected by the surface 51a and the back surface 51b of the first wavelength conversion element 51, and is emitted from the second end face 51d.

[0073] That is, the yellow fluorescence Y propagates through the first translucent member 73 and the first wavelength conversion element 51 while repeatedly being reflected by the front surface 51a and back surface 51b of the first wavelength conversion element 51 and by the first optical layer 61, and is emitted from the area on the second end surface 51d side of the first translucent member 73 or the second end surface 51d of the first wavelength conversion element 51.

[0074] On the other hand, the yellow fluorescence Y3 and Y4 that travels toward the -X side and reaches the first reflecting member 81 is reflected by the first reflecting member 81, travels toward the +X side, and follows the same path as the above-mentioned yellow fluorescence Y1 and Y2. That is, the yellow fluorescence Y3 and Y4 propagate through the first light-transmissive member 73 and the first wavelength conversion element 51 while repeatedly being reflected between the first optical layer 61 and the front surface 51a or the back surface 51b of the first wavelength conversion element 51, and is emitted from the region on the second end face 51d side of the first light-transmissive member 73 or the second end face 51d of the first wavelength conversion element 51.

[0075] Next, the yellow fluorescence Y1, Y2, Y3, and Y4 emitted from the area on the second end face 51d side of the first light-transmissive member 73 or the second end face 51d of the first wavelength conversion element 51 passes through the fourth optical layer 64 and enters the area on the first end face 52c side of the second light-transmissive member 74 or the first end face 52c of the second wavelength conversion element 52.

[0076] On the other hand, the blue fluorescence B converted by the second wavelength conversion element 52 also behaves in the same manner as the yellow fluorescence Y described above. The second excitation light E2 emitted from the second light source 42 passes through the second optical layer 62 and the second translucent member 74 and enters the second wavelength conversion element 52. A part of the second excitation light E2 is backscattered by the front surface 52a and the back surface 52b of the second wavelength conversion element 52 and proceeds toward the second light source 42 side, but is reflected by the second optical layer 62 or the second translucent member 74 and enters the second wavelength conversion element 52.

[0077] When the second excitation light E2 is incident on the second wavelength conversion element 52, the phosphor contained inside the second wavelength conversion element 52 is excited, and blue fluorescence B is emitted from any light-emitting point. At this time, the second excitation light E2 incident on the phosphor is diffused and propagates over an area wider than the incident area, thereby expanding the width of the emission area of ​​the blue fluorescence B, which is called bleeding of the blue fluorescence B.

[0078] The blue fluorescence B incident on the front surface 52a and the back surface 52b of the second wavelength conversion element 52 at an incident angle less than the critical angle is emitted from the second wavelength conversion element 52, enters the second light-transmissive member 74, and propagates through the second light-transmissive member 74. At this time, the blue fluorescence B1 traveling toward the +X side is reflected by the second optical layer 62 and enters the second wavelength conversion element 52 again. In this embodiment, because the second wavelength conversion element 52 is made of a transparent phosphor, the blue fluorescence B1 is not scattered within the second wavelength conversion element 52, and the traveling direction of the blue fluorescence B1 does not change. Therefore, the blue fluorescence B1 enters the second light-transmissive member 74 from the back surface 52b of the second wavelength conversion element 52 and exits from a region on the second end surface 52d side of the second light-transmissive member 74.

[0079] Of the blue fluorescence B emitted from the second wavelength conversion element 52, the blue fluorescence B0 that is incident perpendicularly on the second optical layer 62 is repeatedly reflected between the two second optical layers 62 because the second wavelength conversion element 52 is made of a transparent phosphor and the direction of travel of the blue fluorescence B0 does not change inside the second wavelength conversion element 52.

[0080] The blue fluorescence B2 incident on the front surface 52a and the back surface 52b of the second wavelength conversion element 52 at an incident angle equal to or greater than the critical angle is totally reflected by the front surface 52a and the back surface 52b of the second wavelength conversion element 52. At this time, because the second wavelength conversion element 52 is made of a transparent phosphor and the traveling direction of the blue fluorescence B2 does not change inside the second wavelength conversion element 52, the incident angle of the blue fluorescence B2 on the front surface 52a and the back surface 52b of the second wavelength conversion element 52 also does not change. Therefore, the blue fluorescence B2 is repeatedly totally reflected by the front surface 52a and the back surface 52b of the second wavelength conversion element 52 and is emitted from the second end face 52d.

[0081] That is, the blue fluorescence B propagates through the second light-transmissive member 74 and the second wavelength conversion element 52 while being repeatedly reflected by the front surface 52a and the back surface 52b of the second wavelength conversion element 52 and by the second optical layer 62, and is emitted from the area on the second end surface 52d side of the second light-transmissive member 74 and the second end surface 52d of the second wavelength conversion element 52.

[0082] On the other hand, the blue fluorescence B3 and B4 traveling toward the −X side and reaching the fourth optical layer 64 are reflected by the fourth optical layer 64 and then travel toward the +X side, following the same path as the blue fluorescence B1 and B2 described above. If the fourth optical layer 64 were not provided, part of the blue fluorescence B3 and B4 traveling toward the −X side would be incident on the first wavelength conversion element 51 and absorbed by the yellow phosphor of the first wavelength conversion element 51. This could result in a loss of part of the blue fluorescence B3 and B4, reducing the utilization efficiency of the blue fluorescence B. Therefore, according to the light source device 30A of this embodiment, which includes the fourth optical layer 64, the absorption of part of the blue fluorescence B converted by the second wavelength conversion element 52 by the phosphor of the first wavelength conversion element 51 is suppressed, and the utilization efficiency of the blue fluorescence B can be maintained.

[0083] Furthermore, the yellow fluorescence Y1, Y2 that has passed through the fourth optical layer 64 and entered the second light-transmissive member 74 or the second wavelength conversion element 52 propagates through the second light-transmissive member 74 or the second wavelength conversion element 52, and then exits from the region on the second end face 52d side of the second light-transmissive member 74 or the second end face 52d of the second wavelength conversion element 52. Specifically, the yellow fluorescence Y1 that has entered the second wavelength conversion element 52 from the first light-transmissive member 73 via the fourth optical layer 64 and the second light-transmissive member 74 is incident on the surface 52a of the second wavelength conversion element 52 at an incident angle less than the critical angle, and therefore repeats the behavior of being emitted from the second wavelength conversion element 52 to the second light-transmissive member 74, being reflected by the second optical layer 62, and being again incident on the second wavelength conversion element 52. The yellow fluorescence Y1 then exits from the region on the second end face 52d side of the second light-transmissive member 74.

[0084] On the other hand, the yellow fluorescence Y4 incident on the second wavelength conversion element 52 from the first wavelength conversion element 51 via the fourth optical layer 64 is incident on the surface of the second wavelength conversion element 52 at an incident angle equal to or greater than the critical angle, and therefore propagates through the second wavelength conversion element 52 while repeatedly being totally reflected by the surface 52a and the back surface 52b of the second wavelength conversion element 52. The yellow fluorescence Y4 is then emitted from the second end face 52d of the second wavelength conversion element 52. In this way, the blue fluorescence B converted by the second wavelength conversion element 52 and the yellow fluorescence Y emitted from the region on the second end face 51d side travel through the second light guiding section 72 or the second wavelength conversion element 52 and are emitted from the region on the second end face 52d side of the second light guiding section 72 or the second end face 52d of the second wavelength conversion element 52. This allows the light source device 30A to emit white light LW containing yellow fluorescence Y generated by the first wavelength conversion element 51 and blue fluorescence B generated by the second wavelength conversion element 52 to the outside through the outlet 33k of the housing 31.

[0085] As shown in FIG. 2 , in a plan view in the X-axis direction, which is the normal direction to the second end face 52d of the second wavelength conversion element 52, the extraction port 33k overlaps the second light guiding unit 72 and the second wavelength conversion element 52. Therefore, the region of the second light guiding unit 72 on the second end face 52d side and the second end face 52d of the second wavelength conversion element 52 are exposed to the outside through the extraction port 33k. The extraction port 33k may be closed by a lid made of a translucent material, so that the region of the second light guiding unit 72 on the second end face 52d side and the second end face 52d of the second wavelength conversion element 52 are not exposed to the outside. However, if a lid is provided, some of the yellow fluorescence Y and blue fluorescence B may be reflected by the surface of the lid and may not be extracted to the outside. Therefore, to increase the extraction efficiency of the yellow fluorescence Y and blue fluorescence B, it is preferable not to provide a lid. In the example of FIG. 2, the extraction port 33k overlaps with the second optical layer 62 in addition to the second light guiding section and the second wavelength conversion element 52, but it does not have to overlap with the second optical layer 62.

[0086] In this way, the light source device 30A can extract the white light LW emitted from the region on the second end face 52d side of the second light guiding unit 72 and the second end face 52d of the second wavelength conversion element 52 to the outside through the minimum number of extraction openings 33k. This makes it possible for the light source device 30A to reduce the etendue of the white light LW and reduce loss of the white light LW in optical components such as the integrator optical system 90 arranged downstream of the light source device 30A. As a result, the utilization efficiency of the white light LW in the light source device 30A can be improved.

[0087] Furthermore, by changing the ratio between the length of the first wavelength conversion element 51 and the length of the second wavelength conversion element 52 along the arrangement direction (X-axis direction) in which the first wavelength conversion element 51 and the second wavelength conversion element 52 are arranged, it is possible to change the ratio between the amount of yellow fluorescence Y converted by the first wavelength conversion element 51 and the amount of blue fluorescence B converted by the second wavelength conversion element 52. This makes it possible to adjust the color temperature of the white light LW emitted from the light source device 30A. As a result, it is possible to adjust the color of the image projected by the projector 10. Note that the color temperature of the white light LW may also be adjusted by changing the ratio between the amount of first excitation light E1 from the first light source 41 and the amount of second excitation light E2 from the second light source 42.

[0088] Furthermore, because the first wavelength conversion element 51 is located farther from the output port 33k than the second wavelength conversion element 52, the yellow fluorescence Y travels a longer path than the blue fluorescence B to reach the output port 33k. Therefore, the yellow fluorescence Y is more likely to experience greater loss than the blue fluorescence B. From this perspective, it is desirable that the length of the first wavelength conversion element 51 along the direction in which the first wavelength conversion element 51 and the second wavelength conversion element 52 are arranged side by side (the X-axis direction) is longer than the length of the second wavelength conversion element 52. This makes it possible to increase the amount of light of the yellow fluorescence Y relative to the amount of light of the blue fluorescence B, making it easier to obtain white light LW having a desired color temperature.

[0089] (Effects of the first embodiment) The light source device 30A of this embodiment includes a first light source 41 that emits first excitation light E1, a first wavelength conversion element 51 that converts the first excitation light E1 into yellow fluorescence Y, a first optical layer 61 that is disposed between the first light source 41 and the first wavelength conversion element 51 and that transmits the first excitation light E1 and reflects the yellow fluorescence Y, a first light guiding unit 71 that is disposed between the first optical layer 61 and the first wavelength conversion element 51 and that guides the yellow fluorescence Y converted by the first wavelength conversion element 51, and a second excitation light E2 that emits second excitation light E3. The first wavelength conversion element 51 includes a second light source 42 that transmits the second excitation light E2, a second wavelength conversion element 52 that converts the second excitation light E2 into blue fluorescence B, a second optical layer 62 that is disposed between the second light source 42 and the second wavelength conversion element 52 and transmits the second excitation light E2 and reflects the blue fluorescence B, a second light guiding section 72 that is disposed between the second optical layer 62 and the second wavelength conversion element 52 and guides the blue fluorescence B converted by the second wavelength conversion element 52, and a first reflecting member 81 that reflects the first excitation light E1 and the yellow fluorescence Y. The first wavelength conversion element 51 has a front surface 51a and a back surface 51b onto which the first excitation light E1 is incident via the first optical layer 61 and the first light guiding section 71, and a first end surface 51c and a second end surface 51d that intersect the front surface 51a and the back surface 51b and face opposite each other. The second wavelength conversion element 52 has a front surface 52a and a back surface 52b onto which the second excitation light E2 is incident via the second optical layer 62 and the second light guiding section 72, and a first end surface 52c and a second end surface 52d that intersect with the front surface 52a and the back surface 52b and face opposite each other. A first reflecting member 81 is disposed in a region of the first light guiding section 71 on the first end surface 51c side. The yellow fluorescence Y converted by the first wavelength conversion element 51 travels through the first light guiding section 71 and is emitted from a region of the first light guiding section 71 on the second end surface 51d side, and enters a region of the second light guiding section 72 on the first end surface 52c side. The blue fluorescence B converted by the second wavelength conversion element 52 and the yellow fluorescence Y emitted from the region on the second end surface 51d side travel through the second light guiding section 72 and are emitted from a region of the second light guiding section 72 on the second end surface 52d side.

[0090] As described above, according to the light source device 30A of the present embodiment, a portion of the yellow fluorescence Y generated by the first wavelength conversion element 51 and a portion of the blue fluorescence B generated by the second wavelength conversion element 52 travel through the second light guiding section 72 and are emitted from the region on the second end face 52d side of the second light guiding section 72. Therefore, compared to, for example, a conventional light source device in which all fluorescence propagates inside the wavelength conversion element, there is less loss of the yellow fluorescence Y and the blue fluorescence B, and the utilization efficiency of the yellow fluorescence Y and the blue fluorescence B can be improved. Furthermore, the light source device 30A of the present embodiment can efficiently emit white light LW obtained by combining the yellow fluorescence Y and the blue fluorescence B.

[0091] The projector 10 of this embodiment includes a light source device 30A, light modulation devices 400R, 400G, and 400B that modulate the light emitted from the light source device 30A, and a projection optical device 600 that projects the light modulated by the light modulation devices 400R, 400G, and 400B. According to this configuration, the light source device 30A emits white light LW, so that only one light source device is required, and it is possible to realize a projector 10 that is highly efficient and has a simple configuration.

[0092] [Second embodiment] A second embodiment of the present invention will be described below with reference to FIGS. The basic configuration of the light source device of the second embodiment is the same as that of the first embodiment, but the configuration of each light guide section is different from that of the first embodiment, so a description of the basic configuration of the light source device will be omitted. 6 is a cross-sectional view of a light source device 30B of the second embodiment cut along the XY plane. In Fig. 6, components common to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0093] As shown in Figure 6, the light source device 30B of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 51, a first optical layer 161, a first light guiding section 75, a second light source 42, a second wavelength conversion element 52, a second optical layer 162, a second light guiding section 76, a first reflecting member 81, a second reflecting member (not shown), a third reflecting member (not shown), and a fourth optical layer 64.

[0094] In the light source device 30A of the first embodiment, a first light-transmissive member 73 was disposed in the first light guiding section 71, and a second light-transmissive member 74 was disposed in the second light guiding section 72. In contrast, in the light source device 30B of the present embodiment, the first light guiding section 75 is constituted by a first air layer 77, and the second light guiding section 76 is constituted by a second air layer 78. That is, the first optical layer 161 and the first wavelength conversion element 51 are disposed apart from each other, and air exists between the first optical layer 161 and the first wavelength conversion element 51. The second optical layer 62 and the second wavelength conversion element 52 are disposed apart from each other, and air exists between the second optical layer 162 and the second wavelength conversion element 52. Therefore, in this embodiment, the first optical layer 161 is formed on a first translucent member 161a held by the lid body 33 or the bottom plate portion 32, and the second optical layer 162 is formed on the surface of a second translucent member 162a held by the lid body 33 or the bottom plate portion 32. The other configurations of the light source device 30B are similar to those of the light source device 30A of the first embodiment.

[0095] (Effects of the second embodiment) In the present embodiment, too, the yellow fluorescence Y propagates through the first light-guiding section 75 and the second light-guiding section 76, and the blue fluorescence B propagates through the second light-guiding section 76, thereby achieving the same effects as in the first embodiment, that is, a light source device 30B that is less lost, has excellent utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and can efficiently emit white light LW.

[0096] The effect of the fluorescence Y propagating through the first air layer 77 and the second air layer 78 will be described below. 7 is a schematic diagram for explaining the operation of light source device 30B of this embodiment. The behavior of yellow fluorescence Y relative to the first air layer 77 and the behavior of blue fluorescence B relative to the second air layer 78 are substantially similar, but here, the behavior of blue fluorescence B relative to the second air layer 78 will be illustrated and explained.

[0097] 7, when the blue fluorescence B generated by the second wavelength conversion element 52 reaches the interface K between the second wavelength conversion element 52 and the second light-transmissive member 74, if the incident angle α of the blue fluorescence B with respect to the interface K is less than the critical angle, the blue fluorescence B is not reflected at the interface K but is refracted at a refraction angle β1 and enters the second light-transmissive member 74. Here, if the material of the second wavelength conversion element 52 is SBCA and the material of the second light-transmissive member 74 is quartz, the refractive index of SBCA is, for example, about 1.5 to 2.0 and the refractive index of quartz is about 1.4, so the refractive index difference between the second wavelength conversion element 52 and the second light-transmissive member 74 is about 0.1 to 0.6, which is relatively small.

[0098] In this case, the refraction angle β1 is not very large relative to the incident angle α, and the blue fluorescence B5 incident on the second light-transmissive member 74 travels in a direction nearly perpendicular to the interface K, i.e., in a direction forming a large angle with respect to the X-axis. As a result, the blue fluorescence B5 may leak to the outside from the surface 74b of the second light-transmissive member 74 opposite the interface K, becoming leakage light B6. Alternatively, even if the blue fluorescence B5 becomes fluorescence B7 reflected by the surface 74b of the second light-transmissive member 74, when it propagates through the second light-transmissive member 74 in the X-axis direction and reaches the end surface 74d of the second light-transmissive member 74, the angle of incidence of the blue fluorescence B7 with respect to the end surface 74d is large, so that the blue fluorescence B7 is reflected by the end surface 74d and does not exit from the end surface 74d, which may reduce the extraction efficiency of the blue fluorescence B.

[0099] In contrast, when the second air layer 78 is adjacent to the second wavelength conversion element 52 as in the present embodiment, the refractive index of SBCA is, for example, approximately 1.5 to 2.0, and the refractive index of air is 1.0. Therefore, the refractive index difference between the second wavelength conversion element 52 and the second air layer 78 is approximately 0.5 to 1.0, which is larger than that in the first embodiment. Therefore, the refraction angle β2 is larger than the refraction angle β1, and the blue fluorescence B8 incident on the second air layer 78 travels in a direction that forms a smaller angle with respect to the interface K, i.e., a smaller angle with respect to the X-axis, compared to when the blue fluorescence B8 enters the second light-transmissive member 74. As a result, the blue fluorescence B8 is more likely to be totally reflected when it reaches the interface between the second air layer 78 and another substance, and is less likely to leak to the outside. Furthermore, in the present embodiment, the second air layer 78 is open to the external space at the outlet 33k and does not have a refractive index interface. Therefore, the blue fluorescence B8 that reaches the outlet 33k is directly emitted into the external space without being reflected or refracted. The same effect as that of the blue fluorescence B can be obtained with respect to the yellow fluorescence Y. Due to the above-described action, the light source device 30B of the present embodiment can improve the extraction efficiency of the yellow fluorescence Y and the blue fluorescence B compared to the first embodiment.

[0100] Furthermore, according to the configuration of this embodiment, the adhesive used in the first embodiment for bonding the wavelength conversion elements 51, 52 and the light-transmitting members 73, 74 is not required, so there is no deterioration due to changes in the adhesive over time, and the life of the light source device 30B can be extended. Furthermore, the step of bonding the wavelength conversion elements 51, 52 and the light-transmitting members 73, 74 is not required, so the manufacturing process can be simplified compared to the first embodiment.

[0101] [Third embodiment] A third embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the third embodiment is the same as that of the first embodiment, but the configuration of each wavelength conversion element is different from that of the first embodiment, so a description of the basic configuration of the light source device will be omitted. 8 is a cross-sectional view of a light source device 30C of the third embodiment cut along the XY plane. In Fig. 8, components common to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0102] As shown in Figure 8, the light source device 30C of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 53, a first optical layer 61, a first light guiding section 71, a second light source 42, a second wavelength conversion element 54, a second optical layer 62, a second light guiding section 72, a first reflecting member 81, a second reflecting member (not shown), a third reflecting member (not shown), and a fourth optical layer 64.

[0103] In the light source device 30A of the first embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are made of transparent phosphors. In contrast, in the light source device 30C of the present embodiment, the first wavelength conversion element 53 and the second wavelength conversion element 54 are made of phosphors with light-scattering properties. A phosphor with light-scattering properties can be realized by dispersing a medium with a refractive index different from that of the transparent phosphor, such as pores or a filler, in the transparent phosphor. The first wavelength conversion element 53 has a front surface 53a and a back surface 53b, a first end surface 53c and a second end surface 53d. The second wavelength conversion element 54 has a front surface 54a and a back surface 54b, a first end surface 54c and a second end surface 54d. The other configurations of the light source device 30C are similar to those of the light source device 30A of the first embodiment.

[0104] (Effects of the third embodiment) In the present embodiment, yellow fluorescence Y propagates through the first light-guiding section 71 and the second light-guiding section 72, and blue fluorescence B propagates through the second light-guiding section 72, thereby achieving the same effects as in the first embodiment, that is, a light source device 30C that is less lost, has excellent utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and can efficiently emit white light LW.

[0105] Furthermore, in the case of this embodiment, the first wavelength conversion element 53 and the second wavelength conversion element 54 are made of a phosphor having light scattering properties, and therefore the following effects can be obtained. In the first embodiment, because the wavelength conversion elements 51 and 52 are made of transparent phosphors, the fluorescence Y and B are not scattered when propagating through the wavelength conversion elements 51 and 52, and the direction of propagation of the fluorescence Y and B is not changed. Therefore, the fluorescence Y and B incident on the front surface 51 a and the back surface 51 b of the first wavelength conversion element 51 and the front surface 52 a and the back surface 52 b of the second wavelength conversion element 52 at an incident angle less than the critical angle repeatedly undergoes total reflection at the same incident angle. In this way, the fluorescence Y and B propagate while being confined inside the first wavelength conversion element 51 and the second wavelength conversion element 52, and are emitted from the second end surface 52 d of the second wavelength conversion element 52.

[0106] In contrast, in the present embodiment, since the first wavelength conversion element 53 is made of a phosphor having light-scattering properties, a large amount of scattering occurs when the yellow fluorescence Y propagates through the first wavelength conversion element 53, and the traveling direction of the yellow fluorescence Y changes with each scattering. Therefore, as shown in Fig. 8 , for example, yellow fluorescence Y1 reflected by the first optical layer 61 and incident on the first wavelength conversion element 53 is scattered by the first wavelength conversion element 53 and incident on the first light-transmissive member 73 in an angle-converted state, and is reflected by the first optical layer 61 to be emitted from the region on the second end surface 53d side of the first light-transmissive member 73. Furthermore, a portion of the fluorescence Y2 is transmitted through the first light-transmissive member 73, the fourth optical layer 64, and the second light-transmissive member 74 in this order, and then incident on the second wavelength conversion element 54. The yellow fluorescence Y2 incident on the second wavelength conversion element 54 is scattered by the second wavelength conversion element 54 and then incident on the second light-transmissive member 74 in an angle-converted state, and is emitted from the region on the second end face 54d side of the second light-transmissive member 74.

[0107] The blue fluorescence B behaves in the same manner as the yellow fluorescence Y. For example, the blue fluorescence B1 reflected by the second optical layer 62 and incident on the second wavelength conversion element 54 is scattered by the second wavelength conversion element 54, and is incident on the second light-transmissive member 74 in an angle-converted state, and is emitted from the region on the second end face 54d side of the second light-transmissive member 74. Thus, in the case of this embodiment, there is almost no yellow fluorescence Y or blue fluorescence B propagating while being confined inside the first wavelength conversion element 51 and the second wavelength conversion element 52.

[0108] In the first embodiment, the first wavelength conversion element 51 is made of a transparent phosphor, and the traveling direction of the yellow fluorescence Y does not change inside the first wavelength conversion element 51. Therefore, of the yellow fluorescence Y emitted from the first wavelength conversion element 51, the yellow fluorescence Y0 that is perpendicularly incident on the first optical layers 61 is repeatedly reflected between the two first optical layers 61, as shown in Fig. 3. In contrast, in the case of the present embodiment, the yellow fluorescence Y0 that is perpendicularly incident on the first optical layers 61 is reflected by the first optical layer 61, and then scattered and angle-converted by the first wavelength conversion element 53 when it enters the first wavelength conversion element 53. Therefore, the yellow fluorescence Y0 is not repeatedly reflected between the two first optical layers 61, but propagates inside the first light-transmissive member 73 and the second light-transmissive member 74, and then is emitted to the outside. Similarly, blue fluorescence B0 incident perpendicularly on the second optical layer 62 is scattered and angle-converted by the second wavelength conversion element 54 when it enters the second wavelength conversion element 54, and therefore propagates through the second translucent member 74 without being repeatedly reflected between the two second optical layers 62, and then is emitted to the outside.

[0109] Thus, in this embodiment, the fluorescence Y and B are not confined inside the first wavelength conversion element 53 and the second wavelength conversion element 54, but are emitted to the first light-transmissive member 73 and the second light-transmissive member 74, and after propagating inside the first light-transmissive member 73 and the second light-transmissive member 74, are emitted from the region on the second end face 54d side of the second light-transmissive member 74.

[0110] As described above, the yellow fluorescence Y propagates through the first light guiding section 71 while being repeatedly scattered by the first wavelength conversion element 53 and reflected by the first optical layer 61, and is emitted from the region on the second end face 53d side of the first light guiding section 71. The yellow fluorescence Y and blue fluorescence B emitted from the first light guiding section 71 propagate through the second light guiding section 72 while being repeatedly scattered by the second wavelength conversion element 54 and reflected by the second optical layer 62, and are emitted from the region on the second end face 54d side of the second light guiding section 72. As a result, loss of the fluorescence Y and B when they propagate through the first wavelength conversion element 53 and the second wavelength conversion element 54 is reduced, and the utilization efficiency of the fluorescence Y and B can be further improved compared to the first embodiment.

[0111] [Fourth embodiment] A fourth embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the fourth embodiment is the same as that of the second embodiment, but the configuration of each wavelength conversion element is different from that of the second embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 9 is a cross-sectional view of a light source device 30D of the fourth embodiment cut along the XY plane. In Fig. 9, the same components as those in Fig. 6 used in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0112] As shown in Figure 9, the light source device 30D of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 53, a first optical layer 161, a first light guiding section 75, a second light source 42, a second wavelength conversion element 54, a second optical layer 162, a second light guiding section 76, a first reflecting member 81, a second reflecting member (not shown), a third reflecting member (not shown), and a fourth optical layer 64.

[0113] In the light source device 30B of the second embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are made of transparent phosphors. In contrast, in the light source device 30D of the present embodiment, the first wavelength conversion element 53 and the second wavelength conversion element 54 are made of phosphors having light scattering properties, as in the third embodiment. The first wavelength conversion element 53 has a front surface 53a and a back surface 53b, a first end surface 53c and a second end surface 53d. The second wavelength conversion element 54 has a front surface 54a and a back surface 54b, a first end surface 54c and a second end surface 54d. The other configurations of the light source device 30D are similar to those of the light source device 30B of the second embodiment.

[0114] (Effects of the fourth embodiment) In the present embodiment, yellow fluorescence Y propagates through the first light-guiding section 75 and the second light-guiding section 76, and blue fluorescence B propagates through the second light-guiding section 76, thereby achieving the same effects as in the first embodiment, that is, a light source device 30D that is less lost, has excellent utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and can efficiently emit white light LW.

[0115] Furthermore, in the case of the present embodiment, the first light guiding section 75 is formed by the first air layer 77 and the second light guiding section 76 is formed by the second air layer 78, so that the extraction efficiency of the yellow fluorescence Y and the blue fluorescence B can be improved compared to the first embodiment, and similar effects to the second embodiment can be obtained. Moreover, the first wavelength conversion element 53 and the second wavelength conversion element 54 are formed by phosphors having light scattering properties, so that loss of the fluorescence Y and B when propagating through the first wavelength conversion element 53 and the second wavelength conversion element 54 is suppressed, and thus the utilization efficiency of the fluorescence Y and B can be improved compared to the first embodiment, and similar effects to the third embodiment can be obtained.

[0116] [Fifth embodiment] Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG. The basic configuration of the light source device of the fifth embodiment is the same as that of the third embodiment, but the configuration of each light guide section is different from that of the third embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 10 is a cross-sectional view of a light source device 30E of the fifth embodiment cut along the XY plane. In Fig. 10, components common to those in Fig. 8 used in the third embodiment are given the same reference numerals, and description thereof will be omitted.

[0117] As shown in Figure 10, the light source device 30E of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 53, a first optical layer 61, a first light guiding section 71, a second light source 42, a second wavelength conversion element 54, a second optical layer 162, a second light guiding section 76, a first reflecting member 81, a second reflecting member (not shown), a third reflecting member (not shown), and a fourth optical layer 64.

[0118] In the light source device 30E of this embodiment, the first light guiding section 71 is made of a light-transmitting member 73, and the second light guiding section 76 is made of an air layer 78. That is, the first light guiding section and the second light guiding section do not necessarily have to both be made of a light-transmitting member or both be made of an air layer, as in the above-described embodiment; one may be made of a light-transmitting member and the other an air layer. In this case, as in this embodiment, having the first light guiding section be a light-transmitting member and the second optical layer be an air layer is more preferable than having the first optical layer be an air layer and the second optical layer be a light-transmitting member. This is because a configuration in which the second optical layer closer to the extraction port is an air layer is more effective in increasing the extraction efficiency of the fluorescence Y and B than a configuration in which the second optical layer closer to the extraction port is a light-transmitting member. The other configurations of the light source device 30E are similar to those of the light source device 30C of the third embodiment.

[0119] (Effects of the fifth embodiment) In the present embodiment, too, the yellow fluorescence Y propagates through the first light-guiding section 71 and the second light-guiding section 76, and the blue fluorescence B propagates through the second light-guiding section 76, thereby achieving the same effects as in the first embodiment, that is, a light source device 30E that is less lost, has excellent utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and can efficiently emit white light LW.

[0120] [Sixth embodiment] A sixth embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the sixth embodiment is the same as that of the second embodiment, but differs from the second embodiment in that it includes a third optical layer, so a description of the basic configuration of the light source device will be omitted. Fig. 11 is a cross-sectional view of a light source device 30F of the sixth embodiment cut along the XY plane. In Fig. 11, the same components as those in Fig. 6 used in the second embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0121] As shown in FIG. 11, the light source device 30F of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 51, a first optical layer 161, a first light guiding section 75, a second light source 42, a second wavelength conversion element 52, a second optical layer 162, a second light guiding section 76, a first reflecting member 81, a second reflecting member (not shown), a third reflecting member (not shown), a fourth optical layer 64, and a third optical layer 63.

[0122] The third optical layer 63 is disposed on the front surface 52a and back surface 52b of the second wavelength conversion element 52. The third optical layer 63 has the optical property of reflecting the yellow fluorescence Y and transmitting the second excitation light E2 and the blue fluorescence B. The third optical layer 63 is composed of a dielectric multilayer film formed on the front surface 52a and back surface 52b of the second wavelength conversion element 52. The other configurations of the light source device 30F are similar to those of the light source device 30B of the second embodiment.

[0123] (Effects of the sixth embodiment) In the present embodiment, too, the yellow fluorescence Y propagates through the first light-guiding section 75 and the second light-guiding section 76, and the blue fluorescence B propagates through the second light-guiding section 76, thereby achieving the same effects as in the first embodiment, that is, a light source device 30F that is less lost, has excellent utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and can efficiently emit white light LW.

[0124] In the above-described embodiment not including the third optical layer 63, part of the yellow fluorescence Y that enters the second light guiding section from the first light guiding section is incident on the second wavelength conversion element and absorbed. This may result in a decrease in the utilization efficiency of the yellow fluorescence Y. In contrast, according to the configuration of this embodiment, as shown in FIG. 11 , the yellow fluorescence Y5 that enters the second light guiding section 76 from the first light guiding section 75 is reflected by the third optical layer 63 and does not enter the second wavelength conversion element 52. This makes it possible to improve the utilization efficiency of the yellow fluorescence Y compared to the above-described embodiment. As a result, a highly efficient and compact light source device 30F can be realized.

[0125] [Seventh embodiment] The seventh embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the seventh embodiment is the same as that of the fourth embodiment, but differs from the fourth embodiment in that a third optical layer is provided, so a description of the basic configuration of the light source device will be omitted. Fig. 12 is a cross-sectional view of a light source device 30G of the seventh embodiment cut along the XY plane. In Fig. 12, the same components as those in Fig. 9 used in the fourth embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0126] As shown in Figure 12, the light source device 30G of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 53, a first optical layer 161, a first light guiding section 75, a second light source 42, a second wavelength conversion element 54, a second optical layer 162, a second light guiding section 76, a first reflecting member 81, a second reflecting member (not shown), a third reflecting member (not shown), a fourth optical layer 64, and a third optical layer 63.

[0127] As in the sixth embodiment, the third optical layer 63 is disposed on the front surface 54a and back surface 54b of the second wavelength conversion element 54. The third optical layer 63 has the optical property of reflecting the yellow fluorescence Y and transmitting the second excitation light E2 and the blue fluorescence B. The third optical layer 63 is composed of a dielectric multilayer film formed on the front surface 54a and back surface 54b of the second wavelength conversion element 54. The other configurations of the light source device 30G are similar to those of the light source device 30D of the fourth embodiment.

[0128] (Effects of the Seventh Embodiment) In the present embodiment, yellow fluorescence Y propagates through the first light-guiding section 75 and the second light-guiding section 76, and blue fluorescence B propagates through the second light-guiding section 76, thereby achieving the same effects as in the first embodiment, that is, a light source device 30G in which the yellow fluorescence Y and the blue fluorescence B are little lost, the yellow fluorescence Y and the blue fluorescence B are efficiently utilized, and white light LW can be efficiently emitted.

[0129] Furthermore, because the light guiding sections 75, 76 are formed with an air layer, the extraction efficiency of the yellow fluorescence Y and the blue fluorescence B can be improved compared to the first embodiment, which is an effect similar to that of the second embodiment. Furthermore, because the wavelength conversion elements 53, 54 are formed with a phosphor having light scattering properties, the loss of the fluorescence Y, B when propagating through the wavelength conversion elements 53, 54 is reduced, which is an effect similar to that of the third embodiment, which is an effect similar to that of the sixth .... Furthermore, because the yellow fluorescence Y that enters the second light guiding section 76 from the first light guiding section 75 is reflected by the third optical layer 63, which is an effect similar to that of the sixth embodiment, which is an effect similar to that of the sixth embodiment, which is an effect similar to that of the sixth embodiment, the utilization efficiency of the yellow fluorescence Y can be improved, which makes it possible to realize a highly efficient and compact light source device 30G.

[0130] When the third optical layer 63 is disposed on the front surface 54a and the back surface 54b of the second wavelength conversion element 54 as in the sixth and seventh embodiments, it is desirable that the second light guiding section 76 be made of an air layer. This is because, when the second light guiding section 76 is made of an air layer, the difference in refractive index between the second wavelength conversion element 54 and the air layer is large, which makes it easy to design and manufacture the dielectric multilayer film that constitutes the third optical layer 63. If the second light guiding section 76 were made of a light-transmitting member such as quartz, the difference in refractive index between the second wavelength conversion element 54 and the light-transmitting member would be small, which makes it extremely difficult to design and manufacture the dielectric multilayer film that constitutes the third optical layer 63.

[0131] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, a composite phosphor containing AlN and Ce:YAG may be used as the constituent material of the first wavelength conversion element. According to this configuration, even in a configuration in which the contact area between the first wavelength conversion element and the housing is small and many heat dissipation paths cannot be secured, as in the second embodiment, the thermal conductivity of the first wavelength conversion element can be increased compared to when a phosphor consisting solely of Ce:YAG is used. This improves the cooling efficiency of the first wavelength conversion element. This increases the maximum light intensity of the first excitation light and the maximum output of yellow fluorescence. Similarly, a composite phosphor may also be used for the second wavelength conversion element.

[0132] In the above embodiment, an example was given in which a first light guide and a first optical layer were arranged on the front and back surfaces of the first wavelength conversion element, and a second light guide and a second optical layer were arranged on the front and back surfaces of the second wavelength conversion element. Alternatively, a first light guide and a first optical layer may be arranged on either the front or back surface of the first wavelength conversion element, and a second light guide and a second optical layer may be arranged on either the front or back surface of the second wavelength conversion element. This configuration allows the other of the front and back surfaces of each wavelength conversion element to be in contact with the housing, thereby improving the cooling efficiency of each wavelength conversion element. This increases the maximum light intensity of each excitation light, thereby increasing the maximum output of yellow fluorescence and blue fluorescence B.

[0133] Furthermore, although there is a problem that part of the blue fluorescence is absorbed by the first wavelength conversion element, the light source device of the present invention does not necessarily have to include the fourth optical layer as long as the loss of the blue fluorescence is within an acceptable range.

[0134] In the above embodiment, the first wavelength band is, for example, a wavelength band from violet to blue of 400 nm to 480 nm, and the third wavelength band is, for example, a ultraviolet wavelength band with a central wavelength of 380 nm, but this is not limiting. The first wavelength band may be, for example, a blue wavelength band of 430 nm to 480 nm, and the third wavelength band may be, for example, a violet wavelength band with a central wavelength of 400 nm.

[0135] In addition, the specific descriptions of the shape, number, arrangement, materials, etc. of each component of the light source device and the projector are not limited to the above-described embodiments and can be modified as appropriate. Furthermore, in the above-described embodiments, an example was shown in which the light source device according to the present invention was mounted in a projector using a liquid crystal panel, but this is not limiting. The light source device according to the present invention may also be applied to a projector using a digital micromirror device as a light modulation device. Furthermore, the projector does not need to have multiple light modulation devices, and may have only one light modulation device.

[0136] In the above embodiment, the light source device of the present invention is applied to a projector, 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, and the like.

[0137] Summary of this disclosure A summary of this disclosure is provided below.

[0138] (Appendix 1) a first light source that emits first light in a first wavelength band; a first 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 layer disposed between the first light source and the first wavelength conversion element, the first optical layer transmitting the first light and reflecting the second light; a first light guiding portion disposed between the first optical layer and the first wavelength conversion element and guiding the second light converted by the first wavelength conversion element; a second light source that emits third light in a third wavelength band; a second wavelength conversion element that converts the third light into fourth light in a fourth wavelength band different from the third wavelength band and the second wavelength band; a second optical layer disposed between the second light source and the second wavelength conversion element, the second optical layer transmitting the third light and reflecting the fourth light; a second light guiding portion disposed between the second optical layer and the second wavelength conversion element and configured to guide the fourth light converted by the second wavelength conversion element; a first reflecting member that reflects the first light and the second light; Equipped with the first wavelength conversion element has a first surface onto which the first light is incident via the first optical layer and the first light guiding portion, and a second surface and a third surface that intersect with the first surface and face in opposite directions to each other; the second wavelength conversion element has a fourth surface onto which the third light is incident via the second optical layer and the second light guiding portion, and a fifth surface and a sixth surface that intersect with the fourth surface and face in opposite directions to each other, the first reflecting member is disposed in an area on the second surface side of the first light guiding section, the second light converted by the first wavelength conversion element travels through the first light guiding section, is emitted from a region on the third surface side of the first light guiding section, and is incident on a region on the fifth surface side of the second light guiding section, the fourth light converted by the second wavelength conversion element and the second light emitted from the region on the third surface side travel through the second light guiding section and are emitted from the region on the sixth surface side of the second light guiding section.

[0139] According to the configuration of Supplementary Note 1, the second light is guided through the first light guiding section and the second light guiding section, and the fourth light is guided through the second light guiding section, so that loss of the second light and the fourth light is less than that of conventional light source devices. As a result, it is possible to realize a light source device that has excellent utilization efficiency of the second light and the fourth light and can efficiently emit combined light obtained by combining the second light and the fourth light.

[0140] (Appendix 2) a first light-transmitting member that transmits the first light and the second light is disposed in the first light-guiding portion; a second light-transmissive member that transmits the third light and the fourth light is disposed in the second light-guiding portion; the second light converted by the first wavelength conversion element travels through the first light-transmitting member and is incident on the second light-transmitting member, The light source device described in Appendix 1, wherein the fourth light converted by the second wavelength conversion element and the second light emitted from the first translucent member travel inside the second translucent member and are emitted from the end face of the second translucent member.

[0141] According to the configuration of Appendix 2, heat from the first wavelength conversion element is transferred to the first translucent member, and heat from the second wavelength conversion element is transferred to the second translucent member, thereby suppressing a decrease in conversion efficiency due to an increase in temperature of each wavelength conversion element.

[0142] (Appendix 3) the first light guiding section is a first air layer, the second light guiding section is a second air space, the second light converted by the first wavelength conversion element travels through the first air layer and enters the second air layer, The light source device described in Appendix 1, wherein the fourth light converted by the second wavelength conversion element and the second light emitted from the first air layer travel through the second air layer and are emitted from the area on the sixth surface side of the second air layer.

[0143] According to the configuration of Supplementary Note 3, compared to the configuration of Supplementary Note 2 in which the second light is incident on the first light-transmissive member, the second light travels in a direction that forms a smaller angle with respect to the juxtaposition direction of the first wavelength conversion element and the second wavelength conversion element. As a result, the second light is more likely to be totally reflected when it reaches the interface between each air layer and another substance, and is less likely to leak to the outside. Furthermore, compared to the configuration of Supplementary Note 2 in which the fourth light is incident on the second light-transmissive member, the fourth light travels in a direction that forms a smaller angle with respect to the juxtaposition direction of the first wavelength conversion element and the second wavelength conversion element. As a result, the second light and the fourth light are more likely to be totally reflected when they reach the interface between each air layer and another substance, and are less likely to leak to the outside. This can improve the extraction efficiency of the second light and the fourth light.

[0144] (Appendix 4) The light source device described in Appendix 3, further comprising a third optical layer disposed on the fourth surface of the second wavelength conversion element, which reflects the second light and transmits the third light and the fourth light.

[0145] According to the configuration of Supplementary Note 4, since the third optical layer is disposed on the fourth surface of the second wavelength conversion element, the second light is prevented from entering the second wavelength conversion element, and absorption of the second light when the second light enters the second wavelength conversion element can be suppressed. This makes it possible to improve the utilization efficiency of the second light compared to when the third optical layer is not disposed.

[0146] (Appendix 5) a light-transmitting member that transmits the first light and the second light is disposed in the first light guide portion; the second light guiding section is an air layer, the second light converted by the first wavelength conversion element travels through the light-transmitting member and enters the air layer, The light source device described in Appendix 1, wherein the fourth light converted by the second wavelength conversion element and the second light emitted from the translucent member travel through the air layer and are emitted from the area on the sixth surface side of the air layer.

[0147] According to the configuration of Supplementary Note 5, since the heat of the first wavelength conversion element is transmitted to the light-transmitting member, it is possible to suppress a decrease in conversion efficiency due to a rise in temperature of the first wavelength conversion element. Furthermore, since the second light and the fourth light are likely to be totally reflected when they reach the interface between the air layer and another substance and are less likely to leak to the outside, it is possible to increase the extraction efficiency of the second light and the fourth light.

[0148] (Appendix 6) 6. The light source device according to claim 1, further comprising a fourth optical layer disposed between the first light guide section and the second light guide section, the fourth optical layer transmitting the second light and reflecting the third light and the fourth light.

[0149] According to the configuration of Supplementary Note 6, the fourth light traveling inside the second light guiding section toward the first light guiding section is reflected by the fourth optical layer, so that the fourth light is prevented from being incident on the first wavelength conversion element and being absorbed, resulting in loss, thereby improving the utilization efficiency of the fourth light.

[0150] (Appendix 7) the second wavelength band is larger than the third wavelength band and the fourth wavelength band; 7. The light source device according to claim 1, wherein the third wavelength band is smaller than the first wavelength band.

[0151] According to the configuration of Supplementary Note 7, since the second waveband is wider than the third waveband and the fourth waveband, when the second light is incident on the second wavelength conversion element, it is prevented from being absorbed by the second wavelength conversion element, thereby improving the utilization efficiency of the second light.

[0152] (Appendix 8) the first light is blue light; the second light is yellow fluorescent light, the third light is ultraviolet light, 8. The light source device according to claim 7, wherein the fourth light is blue fluorescent light.

[0153] According to the configuration of Supplementary Note 8, a light source device capable of efficiently emitting white light can be realized.

[0154] (Appendix 9) A light source device described in any one of Appendix 1 to Appendix 8, wherein the length of the first wavelength conversion element along the juxtaposition direction in which the first wavelength conversion element and the second wavelength conversion element are aligned is greater than the length of the second wavelength conversion element along the juxtaposition direction.

[0155] According to the configuration of Supplementary Note 9, the amount of the second light, which is likely to be lost due to a long path, can be made larger relative to the amount of the fourth light, making it easier to obtain combined light having a desired color temperature.

[0156] (Appendix 10) a second reflecting member that reflects the first light and the second light; a third reflecting member that reflects the third light and the fourth light; Furthermore, the first wavelength conversion element has seventh and eighth surfaces that intersect with the first, second, and third surfaces and face in opposite directions; the second wavelength conversion element has a ninth surface and a tenth surface that intersect with the fourth surface, the fifth surface, and the sixth surface and face in opposite directions; the second reflecting member is disposed in an area of ​​the first light guiding section on the seventh surface side and an area of ​​the first light guiding section on the eighth surface side, A light source device described in any one of Supplementary Notes 1 to 9, wherein the third reflecting member is arranged in an area on the ninth surface side of the second light guiding section and an area on the tenth surface side of the second light guiding section.

[0157] According to the configuration of Supplementary Note 10, the second reflecting member can increase the conversion efficiency from the first light to the second light and suppress the loss of the second light, and the third reflecting member can increase the conversion efficiency from the third light to the fourth light and suppress the loss of the fourth light.

[0158] (Appendix 11) further comprising a housing that covers the first optical layer, the second optical layer, the first wavelength conversion element, and the second wavelength conversion element; the housing has an outlet through which the second light and the fourth light emitted from a region on the sixth surface side of the second light guiding section are extracted to the outside, The light source device according to any one of claims 1 to 10, wherein, when viewed in a plane in the normal direction of the sixth surface of the second wavelength conversion element, the outlet overlaps with the second light-guiding section and the second wavelength conversion element.

[0159] According to the configuration of Appendix 11, the housing can protect the first optical layer, the second optical layer, the first wavelength conversion element, and the second wavelength conversion element, and the second light and the fourth light propagating through the first light-guiding section and the second wavelength conversion element can be extracted to the outside through the extraction port of the housing.

[0160] (Appendix 12) 12. The light source device according to claim 1, wherein the first wavelength conversion element and the second wavelength conversion element are made of a transparent phosphor.

[0161] According to the configuration of Appendix 12, even when the first wavelength conversion element and the second wavelength conversion element made of a transparent phosphor are used, the amount of incident light of the first light and the third light can be increased without increasing the size of each wavelength conversion element, thereby improving the conversion efficiency of the second light and the fourth light, and efficiently extracting the second light and the fourth light to the outside.

[0162] (Appendix 13) 12. The light source device according to claim 1, wherein the first wavelength conversion element and the second wavelength conversion element are made of a phosphor having light scattering properties.

[0163] According to the configuration of Supplementary Note 13, the second light generated inside the first wavelength conversion element is efficiently emitted to the first light guiding section and propagates through the first light guiding section and the second light guiding section, so that the loss of the second light is suppressed and the extraction efficiency of the second light can be further increased. Also, the fourth light generated inside the second wavelength conversion element is efficiently emitted to the second light guiding section and propagates through the second light guiding section, so that the loss of the fourth light is suppressed and the extraction efficiency of the fourth light can be further increased.

[0164] (Appendix 14) the first wavelength conversion element includes a yellow phosphor; the first light is blue light; the second light is yellow fluorescent light, the second wavelength conversion element includes a blue phosphor; the third light is ultraviolet light, the fourth light is blue fluorescent light, the yellow fluorescence propagates through the first light guiding unit while being repeatedly scattered by the first wavelength conversion element and reflected by the first optical layer, and is emitted from a region of the first light guiding unit on the third surface side, The light source device described in Appendix 13, wherein the yellow fluorescence and the blue fluorescence emitted from the first light guiding section propagate through the second light guiding section while being repeatedly scattered by the second wavelength conversion element and reflected by the second optical layer, and are emitted from the region on the sixth surface side of the second light guiding section.

[0165] According to the configuration of Supplementary Note 14, the yellow fluorescence generated inside the first wavelength conversion element and the blue fluorescence generated inside the second wavelength conversion element can be efficiently extracted to the outside from the area on the sixth surface side of the first light-guiding section.

[0166] (Appendix 15) A light source device according to any one of Supplementary Note 1 to Supplementary Note 14; a light modulation device that modulates the light emitted from the light source device; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

[0167] According to the configuration of Supplementary Note 15, the light source device emits a combined light that is a combination of the second light and the fourth light, so that only one light source device is required, making it possible to realize a projector that is highly efficient and has a simple configuration. [Explanation of symbols]

[0168] 10...Projector, 30A, 30B, 30C, 30D, 30E, 30F, 30G...Light source device, 31...Housing, 33k...Outlet, 41...First light source, 42...Second light source, 51, 53...First wavelength conversion element, 51a, 53a...Surface (first surface), 51c, 53c...First end surface (second surface), 51d, 53d...Second end surface (third surface), 51e...First side surface (seventh surface), 51f...Second side surface (eighth surface), 52, 54...Second wavelength conversion element, 52a, 54a...Surface (fourth surface), 52c, 54c...First end surface (fifth surface), 52d, 54d...Second end surface (sixth surface), 52e...First side surface (ninth surface), 51f...Second Side surface (tenth surface), 61,161...first optical layer, 62,162...second optical layer, 63...third optical layer, 64...fourth optical layer, 71,75...first light-guiding section, 73...first light-transmissive member, 72,76...second light-guiding section, 74...second light-transmissive member, 77...first air layer, 78...second air layer, 81...first reflecting member, 82...second reflecting member, 83...third reflecting member, 400B...blue light optical modulation device, 400G...green light optical modulation device, 400R...red light optical modulation device, 600...projection optical device, E1...first excitation light (first light), Y...yellow fluorescence (second light), E2...second excitation light (third light), B...blue fluorescence (fourth light).

Claims

1. a first light source that emits first light in a first wavelength band; a first 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 layer disposed between the first light source and the first wavelength conversion element, the first optical layer transmitting the first light and reflecting the second light; a first light guiding portion disposed between the first optical layer and the first wavelength conversion element and configured to guide the second light converted by the first wavelength conversion element; a second light source that emits third light in a third wavelength band; a second wavelength conversion element that converts the third light into fourth light in a fourth wavelength band different from the third wavelength band and the second wavelength band; a second optical layer disposed between the second light source and the second wavelength conversion element, the second optical layer transmitting the third light and reflecting the fourth light; a second light guiding portion disposed between the second optical layer and the second wavelength conversion element and configured to guide the fourth light converted by the second wavelength conversion element; a first reflecting member that reflects the first light and the second light; Equipped with the first wavelength conversion element has a first surface onto which the first light is incident via the first optical layer and the first light guiding portion, and a second surface and a third surface that intersect with the first surface and face in opposite directions to each other, the second wavelength conversion element has a fourth surface onto which the third light is incident via the second optical layer and the second light guiding portion, and a fifth surface and a sixth surface that intersect with the fourth surface and face in opposite directions to each other, the first reflecting member is disposed in an area on the second surface side of the first light guiding section, the second light converted by the first wavelength conversion element travels through the first light guiding section, is emitted from a region on the third surface side of the first light guiding section, and is incident on a region on the fifth surface side of the second light guiding section, the fourth light converted by the second wavelength conversion element and the second light emitted from the region on the third surface side travel through the second light guiding section and are emitted from the region on the sixth surface side of the second light guiding section.

2. a first light-transmitting member that transmits the first light and the second light is disposed in the first light-guiding portion; a second light-transmissive member that transmits the third light and the fourth light is disposed in the second light guide portion; the second light converted by the first wavelength conversion element travels through the first light-transmitting member and is incident on the second light-transmitting member, 2. The light source device according to claim 1, wherein the fourth light converted by the second wavelength conversion element and the second light emitted from the first translucent member travel inside the second translucent member and are emitted from an end face of the second translucent member.

3. the first light guiding portion is a first air layer, the second light guiding portion is a second air layer, the second light converted by the first wavelength conversion element travels through the first air layer and enters the second air layer, The light source device of claim 1, wherein the fourth light converted by the second wavelength conversion element and the second light emitted from the first air layer travel through the second air layer and are emitted from the area on the sixth surface side of the second air layer.

4. The light source device according to claim 3 , further comprising a third optical layer disposed on the fourth surface of the second wavelength conversion element, the third optical layer reflecting the second light and transmitting the third light and the fourth light.

5. a light-transmitting member that transmits the first light and the second light is disposed in the first light guide portion; the second light guiding section is an air layer, the second light converted by the first wavelength conversion element travels through the light-transmitting member and enters the air layer, 2. The light source device according to claim 1, wherein the fourth light converted by the second wavelength conversion element and the second light emitted from the translucent member travel through the air layer and are emitted from a region on the sixth surface side of the air layer.

6. 6. The light source device according to claim 1, further comprising a fourth optical layer disposed between the first light guiding section and the second light guiding section, the fourth optical layer transmitting the second light and reflecting the third light and the fourth light.

7. the second wavelength band is larger than the third wavelength band and the fourth wavelength band; The light source device according to claim 1 , wherein the third wavelength band is smaller than the first wavelength band.

8. the first light is blue light, the second light is yellow fluorescent light, the third light is ultraviolet light, The light source device according to claim 7 , wherein the fourth light is blue fluorescent light.

9. 6. The light source device according to claim 1, wherein a length of the first wavelength conversion element along a direction in which the first wavelength conversion element and the second wavelength conversion element are arranged is greater than a length of the second wavelength conversion element along the direction in which the first wavelength conversion element and the second wavelength conversion element are arranged.

10. a second reflecting member that reflects the first light and the second light; a third reflecting member that reflects the third light and the fourth light; Furthermore, the first wavelength conversion element has a seventh surface and an eighth surface that intersect with the first surface, the second surface, and the third surface and face in opposite directions; the second wavelength conversion element has a ninth surface and a tenth surface that intersect with the fourth surface, the fifth surface, and the sixth surface and face in opposite directions; the second reflecting member is disposed in an area of ​​the first light guiding section on the seventh surface side and an area of ​​the first light guiding section on the eighth surface side, 6. The light source device according to claim 1, wherein the third reflecting member is disposed in an area on the ninth surface side of the second light guiding section and an area on the tenth surface side of the second light guiding section.

11. a housing that covers the first optical layer, the second optical layer, the first wavelength conversion element, and the second wavelength conversion element; the housing has an outlet through which the second light and the fourth light emitted from a region on the sixth surface side of the second light guide section are extracted to the outside, 6. The light source device according to claim 1, wherein, when viewed in a plane in a normal direction of the sixth surface of the second wavelength conversion element, the outlet overlaps with the second light guiding section and the second wavelength conversion element.

12. The light source device according to claim 1 , wherein the first wavelength conversion element and the second wavelength conversion element are made of a transparent phosphor.

13. The light source device according to claim 1 , wherein the first wavelength conversion element and the second wavelength conversion element are made of a phosphor having light scattering properties.

14. the first wavelength conversion element includes a yellow phosphor; the first light is blue light, the second light is yellow fluorescent light, the second wavelength conversion element includes a blue phosphor, the third light is ultraviolet light, the fourth light is blue fluorescent light, the yellow fluorescence propagates through the first light guiding unit while being repeatedly scattered by the first wavelength conversion element and reflected by the first optical layer, and is emitted from a region of the first light guiding unit on the third surface side, 14. The light source device according to claim 13, wherein the yellow fluorescence and the blue fluorescence emitted from the first light guiding section propagate through the second light guiding section while being repeatedly scattered by the second wavelength conversion element and reflected by the second optical layer, and are emitted from a region on the sixth surface side of the second light guiding section.

15. The light source device according to any one of claims 1 to 5, a light modulation device that modulates the light emitted from the light source device; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

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