Light source device and projector

Abstract

To provide a light source device and a projector that are 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, a second light guide portion guiding the fourth light, and a first reflection member. The second wavelength conversion element is disposed at a side opposite to the first light source with respect to the first wavelength conversion element. The second light travels through the first light guide portion and is emitted from a region of the first light guide portion at a third surface side, and the fourth light travels through the second light guide portion and is emitted from a region of the second light guide portion at a 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 transmits the first light and reflects the second light, a first light guiding section that is disposed between the first optical layer and the first wavelength conversion element and guides the second light converted by the first wavelength conversion element, and a second light guiding section that emits third light in a third wavelength band. The optical fiber includes a second light source configured to transmit the third light, a second wavelength conversion element configured to convert 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 and transmitting the third light and reflecting the fourth light, a second light guiding section disposed between the second optical layer and the second wavelength conversion element and guiding the fourth light converted by the second wavelength conversion element, and a first reflecting member configured to reflect the first light, the second light, the third light, and the fourth 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 and a region on the fifth surface side of the second light guiding section. The second wavelength conversion element is disposed on the opposite side of the first wavelength conversion element from the first light source. The second light converted by the first wavelength conversion element travels through the first light guiding section and is emitted from the region on the third surface side of the first light guiding section, and the fourth light converted by the second wavelength conversion element travels through the second light guiding section and is emitted from the region on the sixth surface side of the second light guiding section.

[0006] Another embodiment of the light source device 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 arranged between the first light source and the first wavelength conversion element and that transmits the first light and reflects the second light, 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 that is arranged between the second light source and the second wavelength conversion element and that transmits the third light and reflects the fourth light, a light guiding section that is arranged between the first wavelength conversion element and the second wavelength conversion element and that guides the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element, and a first reflecting member that reflects the first light, the second light, the third light, and the fourth 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 second wavelength conversion element is disposed on the opposite side of the first wavelength conversion element from the first light source. The first reflecting member is disposed in an area on the second surface side of the light guiding section. The second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element travel through the light guiding section and are emitted from an area on the third surface side of the light guiding section.

[0007] 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]

[0008] [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] FIG. 10 is a cross-sectional view of a light source device according to a second embodiment. [Figure 6] FIG. 10 is a cross-sectional view of a light source device according to a third embodiment. [Figure 7] FIG. 10 is a cross-sectional view of a light source device according to a fourth embodiment. [Figure 8] FIG. 10 is a perspective view of a light source device according to a fifth embodiment. [Figure 9] 9 is a cross-sectional view of the light source device taken along line IX-IX in FIG. 8. [Figure 10] 10A and 10B are schematic diagrams for explaining the operation of the light source device of the 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. [Figure 13] FIG. 13 is a cross-sectional view of a light source device according to an eighth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] [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.

[0010] 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] The configurations of the light source device 30A and the illumination device 20 will be described below. Fig. 2 is a perspective view of a light source device 30A of this embodiment. Fig. 3 is a cross-sectional view of the light source device 30A taken along line III-III in Fig. 2. Fig. 4 is a cross-sectional view of the light source device 30A taken along line IV-IV in Fig. 3.

[0023] As shown in Figures 2 to 4, 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 third reflecting member 83, and a fourth reflecting member 84.

[0024] 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 third reflecting member 83, and the fourth reflecting member 84. The housing 31 is composed of a bottom plate 32 and a lid 33. The bottom plate 32 has a generally 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.

[0025] The bottom plate portion 32 is disposed along the XZ plane and supports 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 configured integrally with the base portion 32a and is provided on the surface located on the +Y side of the base portion 32a. The bottom plate portion 32 has a recess that accommodates the second light source 42.

[0026] The bottom plate portion 32 is connected to the second light source 42 so as to be able to transfer heat. 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.

[0027] 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.

[0028] The lid 33 accommodates the first light source 41, the first optical layer 61, the first light guide 71, the first wavelength conversion element 51, the second optical layer 62, the second light guide 72, the second wavelength conversion element 52, the first reflecting member 81, the third reflecting member 83, and the fourth reflecting member 84. The top wall 33a is connected to the first light source 41 in a heat-transferable manner. The third side wall 33e and the fourth side wall 33f are connected to the first wavelength conversion element 51 and the second wavelength conversion element 52 via the third reflecting member 83 and the fourth reflecting member 84 in a heat-transferable manner. For this reason, like the bottom plate 32, the lid 33 is desirably made of a material that has a predetermined strength and high thermal conductivity. For this reason, like the bottom plate, the lid 33 is desirably made of a metal such as aluminum or stainless steel, and in particular, an aluminum alloy such as a 6061 series aluminum alloy.

[0029] 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 temperature rise in the first wavelength conversion element 51 and the second wavelength conversion element 52. As a result, a decrease in wavelength conversion efficiency due to a temperature rise in the first wavelength conversion element 51 and the second wavelength conversion element 52 can be suppressed.

[0030] 3, the first reflecting member 81 is disposed on the first side wall 33c of the lid 33. As shown in Fig. 4, the third reflecting member 83 is disposed on the third side wall 33e of the lid 33. The fourth reflecting member 84 is disposed on the fourth side wall 33f of the lid 33. The extraction outlet 33k is provided on the second side wall 33d of the lid 33. The extraction outlet 33k is an opening for extracting to the outside the yellow fluorescence Y emitted from the first light guiding unit 71 and the first wavelength conversion element 51, and the blue fluorescence B emitted from the second light guiding unit 72 and the second wavelength conversion element 52.

[0031] The lid 33 is disposed so as to abut against the base 32a of the bottom plate 32. The lid 33 and the bottom plate 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 71, the first wavelength conversion element 51, the second light source 42, the second optical layer 62, the second light guide 72, the second wavelength conversion element 52, the first reflecting member 81, the third reflecting member 83, and the fourth reflecting member 84 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.

[0032] The first light source 41 has a plurality of first light-emitting elements 411. The plurality of first light-emitting elements 411 are respectively mounted on the top wall 33a of the housing 31. Note that 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 the center wavelength is, 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 first excitation light E1 in the first wavelength band, which is composed of a plurality of blue first excitation light rays, toward the first wavelength conversion element 51. The first excitation light E1 in this embodiment corresponds to the first light in the claims.

[0033] 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.

[0034] The first wavelength conversion element 51 has a front surface 51a and a back surface 51b, a first end surface 51c and a second end surface 51d, and 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 along the Y axis. The back surface 51b is located on the -Y side, which is the other side along the Y axis. First excitation light E1 is incident on the front surface 51a from the first light source 41 disposed on the top wall 33a 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.

[0035] 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.

[0036] 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.

[0037] 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 surface 51 a to the first light guiding section 71.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] The first optical layer 61 is disposed between the first light source 41 and the first wavelength conversion element 51. The first optical layer 61 has optical properties of transmitting the first excitation light E1 and reflecting the yellow fluorescence Y. The first optical layer 61 is configured 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.

[0042] The first light guiding section 71 is disposed between the first optical layer 61 and the first wavelength conversion element 51. 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 surface 51a of the first wavelength conversion element 51 with an optical adhesive.

[0043] 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.

[0044] 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.

[0045] As shown in FIG. 3 , the second light source 42 has a plurality of second light-emitting elements 421. The plurality of second light-emitting elements 421 are mounted on the bottom plate 32 of the housing 31. 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, by 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 plurality of 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.

[0046] The second wavelength conversion element 52 is disposed on the -Y side of the first wavelength conversion element 51. That is, the second wavelength conversion element 52 is disposed on the opposite side of the first wavelength conversion element 51 from the first light source 41. In this embodiment, the back surface 51b of the first wavelength conversion element 51 and the back surface 52b of the second wavelength conversion element 52 are bonded to each other via a bonding material (not shown) such as an optical adhesive. With this configuration, the first wavelength conversion element 51 and the second wavelength conversion element 52 can be handled as an integrated member, which simplifies the manufacturing process of the light source device. Furthermore, since the first wavelength conversion element 51 and the second wavelength conversion element 52 are disposed side by side in a direction (Y-axis direction) perpendicular to the longitudinal direction (X-axis direction) of each wavelength conversion element 51, 52, the length in the X-axis direction does not become too long, and a compact light source device 30A can be realized.

[0047] 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 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. 4.

[0048] The second wavelength conversion element 52 has a front surface 52a and a back surface 52b, a first end surface 52c and a second end surface 52d, and a first side surface 52e and a second side surface 52f. The front surface 52a and the back surface 52b intersect with 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 along the Y axis. The back surface 52b is located on the +Y side, which is the other side along the Y axis. The second excitation light E2 is incident on the front surface 52a from the second light source 42 disposed 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.

[0049] As shown in Fig. 3, the first end face 52c and the second end face 52d intersect the front face 52a and the back face 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. 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.

[0050] As shown in FIG. 4, 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.

[0051] 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, part of the blue fluorescence B generated inside the second wavelength conversion element 52 is emitted from the surface 52a to the second light guiding section 72.

[0052] 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 material of the second wavelength conversion element 52 is BaMgAl 10 O 17Eu(II), etc. may also be used. The blue fluorescence B of this embodiment corresponds to the fourth light of the claims.

[0053] The second optical layer 62 is disposed between the second light source 42 and the second wavelength conversion element 52. The second optical layer 62 has optical properties of transmitting the second excitation light E2 and reflecting the blue fluorescence B. The second optical layer 62 is configured of, for example, a dielectric multilayer film. The second optical layer 62 is disposed on a surface of the second light-transmissive member 74, which will be described later, that faces the second light source 42. Furthermore, the second optical layer 62 reflects light having wavelengths equal to or greater than the fourth wavelength band, and therefore reflects not only the blue fluorescence B but also the yellow fluorescence Y generated by the first wavelength conversion element 51.

[0054] The second light guiding section 72 is disposed between the second optical layer 62 and the second wavelength conversion element 52. The second light guiding section 72 guides the blue fluorescence B converted by the second wavelength conversion element 52. In the present embodiment, a second light-transmissive member 74 that transmits the second excitation light E2 and the blue fluorescence B is disposed in the second light guiding section 72. The second light-transmissive member 74 is bonded to the surface 52a of the second wavelength conversion element 52 with an optical adhesive.

[0055] 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 needs to be made of a material that can transmit the second excitation light E2 and the blue fluorescence B. The second light-transmissive member 74 has a plate-like shape extending along the X-axis. As shown in FIG. 4 , the second light-transmissive member 74 has a rectangular cross-sectional shape cut 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.

[0056] 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.

[0057] 3, the first reflecting member 81 is disposed on the −X side of the first light source 41, the first optical layer 61, the first light guiding section 71, the first wavelength conversion element 51, the second wavelength conversion element 52, the second light guiding section 72, the second optical layer 62, and the second light source 42. The first reflecting member 81 is disposed on the first side wall 33c of the housing 31. Note that the first reflecting member 81 does not necessarily have to be provided over the entire region described above, but only needs to be provided in at least the region on the first end face 51c side of the first light guiding section 71 and the region on the first end face 52c side of the second light guiding section 72.

[0058] 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, and the blue fluorescence B that has propagated through the second light guiding unit 72 and the second wavelength conversion element 52 and reached the first reflecting member 81. The first reflecting member 81 also reflects the first excitation light E1 that has propagated through the first wavelength conversion element 51 or the first light guiding unit 71 and reached the first reflecting member 81, and the second excitation light E2 that has propagated through the second wavelength conversion element 52 or the second light guiding unit 72 and reached the first reflecting member 81. That is, the first reflecting member 81 reflects the yellow fluorescence Y, the blue fluorescence B, the first excitation light E1, and the second excitation light E2. The first reflecting member 81 is formed of, for example, a metal film, a dielectric multilayer film, or a scattering member containing barium sulfate.

[0059] 4, the third reflecting member 83 is disposed on the third side wall 33e of the housing 31 so as to face the first side surface 51e of the first wavelength conversion element 51, the region on the first side surface 51e side of the first light guiding unit 71, the first side surface 52e of the second wavelength conversion element 52, and the region on the first side surface 52e side of the second light guiding unit 72. The fourth reflecting member 84 is disposed on the fourth side wall 33f of the housing 31 so as to face the second side surface 51f of the first wavelength conversion element 51, the region on the second side surface 51f side of the first light guiding unit 71, the second side surface 52f of the second wavelength conversion element 52, and the region on the second side surface 52f side of the second light guiding unit 72.

[0060] The third reflecting member 83 reflects the yellow fluorescence Y, the blue fluorescence B, the first excitation light E1, and the second excitation light E2. Therefore, the third reflecting member 83 reflects the first excitation light E1 that is reflected by the surface 51a of the first wavelength conversion element 51 to enter the first light guiding unit 71 and reaches the third reflecting member 83, and then reflects it to the first wavelength conversion element 51. This increases the conversion efficiency of the first excitation light E1 to the yellow fluorescence Y. Furthermore, 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 to enter the second light guiding unit 72 and reaches the third reflecting member 83, and then reflects it to the second wavelength conversion element 52. This increases the conversion efficiency of the second excitation light E2 to the blue fluorescence B.

[0061] Furthermore, the third reflecting member 83 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 third reflecting member 83, as well as the yellow fluorescence Y that is guided inside the first wavelength conversion element 51 and reaches the third reflecting member 83. This makes it possible to suppress loss of the yellow fluorescence Y. The third reflecting member 83 also 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 makes it possible to suppress loss of the blue fluorescence B.

[0062] Similarly, the fourth reflecting member 84 reflects the yellow fluorescence Y, the blue fluorescence B, the first excitation light E1, and the second excitation light E2. The action and effect of the fourth reflecting member 84 are similar to those of the above-mentioned third reflecting member 83. The third reflecting member 83 and the fourth reflecting member 84 are made of, for example, a metal film, a dielectric multilayer film, a scattering member, or the like.

[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 is incident on the first wavelength conversion element 51. Note that a part of the first excitation light E1 is backscattered by the surface 51a 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 is incident on 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 light-transmissive member 73, and propagates inside the first light-transmissive member 73. At this time, the fluorescence Y1 traveling toward the +X side is reflected by the first optical layer 61, propagates inside the first light-transmissive member 73, and is emitted to the outside from the end face of the first light-transmissive member 73 on the second end face 51d side.

[0071] On the other hand, the yellow fluorescence Y2 traveling toward the -X side and reaching the first reflecting member 81 is reflected by the first reflecting member 81, travels toward the +X side, and enters the first wavelength conversion element 51 again. In this embodiment, since the first wavelength conversion element 51 is made of a transparent phosphor, the yellow fluorescence Y2 is not scattered inside the first wavelength conversion element 51, and the traveling direction of the yellow fluorescence Y2 does not change inside the first wavelength conversion element 51. In addition, the refractive index of the first wavelength conversion element 51 and the refractive index of the second wavelength conversion element 52 are substantially the same. Therefore, the yellow fluorescence Y2 enters the second wavelength conversion element 52 from the first wavelength conversion element 51 without being refracted at the interface between the first wavelength conversion element 51 and the second wavelength conversion element 52. The yellow fluorescence Y2 that entered the second wavelength conversion element 52 enters the second light-transmissive member 74 and is emitted to the outside from the end face of the second light-transmissive member 74 on the second end face 52d side.

[0072] 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 layer 61 is repeatedly reflected between the first optical layer 61 and the second optical layer 62 because the first wavelength conversion element 51 is made of a transparent phosphor and the traveling direction of the yellow fluorescence Y0 does not change inside the first wavelength conversion element 51. Note that part of the yellow fluorescence Y0 is absorbed by the phosphor while propagating inside the first wavelength conversion element 51 and the second wavelength conversion element 52, resulting in loss.

[0073] The yellow fluorescence Y3 incident on the surface 51a 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 of the first wavelength conversion element 51. At this time, the first wavelength conversion element 51 and the second wavelength conversion element 52 are made of transparent phosphors, and the traveling direction of the yellow fluorescence Y3 does not change inside the first wavelength conversion element 51 and the second wavelength conversion element 52, so the incident angle of the yellow fluorescence Y3 with respect to the surface 52a of the second wavelength conversion element 52 does not change either. Therefore, the yellow fluorescence Y3 is repeatedly totally reflected between the surface 51a of the first wavelength conversion element 51 and the surface 52a of the second wavelength conversion element 52, and is emitted from the second end face 51d or the second end face 52d.

[0074] On the other hand, the second excitation light E2 emitted from the second light source 42 passes through the second optical layer 62 and the second light-transmissive member 74 and enters the second wavelength conversion element 52. A part of the second excitation light E2 is backscattered by the surface 52a of the second wavelength conversion element 52 and travels toward the second light source 42, but is reflected by the second optical layer 62 or the second light-transmissive member 74 and enters the second wavelength conversion element 52.

[0075] 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.

[0076] The blue fluorescence B incident on the surface 52a 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 inside the second light-transmissive member 74. At this time, the blue fluorescence B1 traveling toward the +X side is emitted to the outside from the end face of the second light-transmissive member 74 on the second end face 52d side. Alternatively, the blue fluorescence traveling toward the +X side is reflected by the second optical layer 62, propagates inside the second light-transmissive member 74, and is emitted to the outside from the end face of the second light-transmissive member 74 on the second end face 52d side.

[0077] On the other hand, the blue fluorescence B2 that travels toward the -X side and reaches the first reflecting member 81 is reflected by the first reflecting member 81, then travels toward the +X side, is reflected by the second optical layer 62, propagates inside the second translucent member 74, and is emitted to the outside from the end face of the second translucent member 74 on the second end face 52d side.

[0078] Of the blue fluorescence B converted by the second wavelength conversion element 52, fluorescence B3 enters the first wavelength conversion element 51 from the back surface 52b of the second wavelength conversion element 52. Meanwhile, the other blue fluorescence B4 is emitted to the second light-transmissive member 74, reflected by the second optical layer 62, propagates through the second wavelength conversion element 52, and enters the first wavelength conversion element 51 from the back surface 52b of the second wavelength conversion element 52. The blue fluorescence B3 and B4 entering the first wavelength conversion element 51 excite the yellow phosphor contained in the first wavelength conversion element 51. As a result, the blue fluorescence B3 and B4 are converted into yellow fluorescence Y, and the yellow fluorescence Y is emitted from any light-emitting point of the first wavelength conversion element 51.

[0079] In this way, the light source device 30A can emit white light LW containing yellow fluorescence Y converted by the first wavelength conversion element 51 and blue fluorescence B converted by the second wavelength conversion element 52 to the outside from the outlet 33k of the housing 31.

[0080] As shown in FIG. 2 , in a planar 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 first light guiding unit 71, the first wavelength conversion element 51, the second wavelength conversion element 52, and the second light guiding unit 72. Therefore, the end face of the first light-transmissive member 73 on the second end face 51d side, the second end face 51d of the first wavelength conversion element 51, the second end face 52d of the second wavelength conversion element 52, and the end face of the second light-transmissive member 74 on the second end face 52d side are exposed to the outside through the extraction port 33k. The extraction port 33k may be closed by a lid made of a light-transmissive member, so that the end faces 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 outlet 33k overlaps the first optical layer 61 and the second optical layer 62, but it does not have to overlap the first optical layer 61 and the second optical layer 62.

[0081] In this way, the light source device 30A can extract the white light LW emitted from the end face on the second end face 51d side of the first light-transmissive member 73, the second end face 51d of the first wavelength conversion element 51, the second end face 52d of the second wavelength conversion element 52, and the end face on the second end face 52d side of the second light-transmissive member 74 to the outside via the minimum number of extraction ports 33k. As a result, the light source device 30A can reduce the etendue of the white light LW, thereby reducing 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.

[0082] Furthermore, by changing the ratio between the thickness of the first wavelength conversion element 51 and the thickness of the second wavelength conversion element 52 along the arrangement direction (Y-axis direction) of the first wavelength conversion element 51 and the second wavelength conversion element 52, 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. At the same time, the color temperature of the white light LW may 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.

[0083] (Effects of the first embodiment) The light source device 30A of this embodiment includes a first light source 41 that emits a 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 light source 42 that emits a second excitation light E2. The first wavelength conversion element 51 includes 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 that 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 that 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, the yellow fluorescence Y, the second excitation light E2, and the blue fluorescence B. The first wavelength conversion element 51 has a surface 51a on 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 face 51c and a second end face 51d that intersect the surface 51a and face opposite each other. The second wavelength conversion element 52 has a surface 52a on 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 face 52c and a second end face 52d that intersect with the surface 52a and face in opposite directions. A first reflecting member 81 is disposed in an area on the first end face 51c side of the first light guiding section 71 and an area on the first end face 52c side of the second light guiding section 72. The second wavelength conversion element 52 is disposed on the opposite side of the first wavelength conversion element 51 from the first light source 41 with respect to the first wavelength conversion element 51. The yellow fluorescence Y converted by the first wavelength conversion element 51 travels through the first light guiding section 71 and is emitted from an area on the second end face 51d side of the first light guiding section 71, and the blue fluorescence B converted by the second wavelength conversion element 52 travels through the second light guiding section 72 and is emitted from an area on the second end face 52d side of the second light guiding section 72.

[0084] As described above, according to the light source device 30A of this embodiment, the yellow fluorescence Y generated by the first wavelength conversion element 51 travels through the first light guiding section 71, and the blue fluorescence B generated by the second wavelength conversion element 52 travels through the second light guiding section 72 and is emitted from the region on the second end surface 51d, 52d side of each light guiding section 71, 72. Therefore, compared to conventional light source devices 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 this embodiment can efficiently emit white light LW obtained by combining the yellow fluorescence Y and the blue fluorescence B.

[0085] 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.

[0086] [Second embodiment] A second embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the second embodiment is similar to that of the first embodiment, and therefore a description of the basic configuration of the light source device will be omitted. 5 is a cross-sectional view of a light source device 30B of the second embodiment cut along the XY plane. In FIG. 5, components common to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0087] As shown in Figure 5, 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 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 third reflecting member (not shown), and a fourth reflecting member (not shown).

[0088] In the light source device 30A of the first embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are bonded to each other via an optical adhesive. In contrast, in the light source device 30B of the present embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are not bonded to each other but are spaced apart from each other. Air exists in the space between the first wavelength conversion element 51 and the second wavelength conversion element 52. That is, an air layer 56 is provided between the first wavelength conversion element 51 and the second wavelength conversion element 52. The other configurations of the light source device 30B are similar to those of the light source device 30A of the first embodiment.

[0089] (Effects of the second embodiment) In the present embodiment, yellow fluorescence Y propagates through the first light-guiding section 71, and blue fluorescence B propagates through the second light-guiding section 72, thereby achieving the same effects as in the first embodiment, such as reducing the loss of yellow fluorescence Y and blue fluorescence B and realizing a light source device 30B that is excellent in utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and realizing a light source device 30B that can efficiently emit white light LW.

[0090] In the first embodiment, because the first wavelength conversion element 51 and the second wavelength conversion element 52 are joined together, part of the blue fluorescence B generated by the second wavelength conversion element 52 enters the first wavelength conversion element 51 and is converted into yellow fluorescence Y. In this case, not only is the amount of blue fluorescence B reduced, but the yellow fluorescence Y is generated through two wavelength conversions: conversion of the second excitation light E2 into blue fluorescence B by the second wavelength conversion element 52, and conversion of the blue fluorescence B into yellow fluorescence Y by the first wavelength conversion element 51. This results in a problem of reduced wavelength conversion efficiency. Furthermore, even when part of the yellow fluorescence Y generated by the first wavelength conversion element 51 enters the second wavelength conversion element 52, a loss of yellow fluorescence Y occurs.

[0091] In contrast, in the present embodiment, an air layer 56 is provided between the first wavelength conversion element 51 and the second wavelength conversion element 52. This increases the refractive index difference between the rear surfaces 51b, 52b of the wavelength conversion elements 51, 52 compared to the first embodiment, and increases the critical angle between the rear surfaces 51b, 52b of the wavelength conversion elements 51, 52 compared to the first embodiment. Therefore, when the fluorescence Y, B generated by one of the wavelength conversion elements 51, 52 reaches the rear surfaces 51b, 52b of the wavelength conversion elements 51, 52, it is more likely to be totally reflected at the interface with the air layer 56 and less likely to enter the other wavelength conversion element 52, 51. As a result, while the fluorescence B3 shown in FIG. 3 of the first embodiment enters the first wavelength conversion element 51, as shown in FIG. 5, the fluorescence B3 of this embodiment is totally reflected by the rear surface 52b of the second wavelength conversion element 52 and does not enter the first wavelength conversion element 51. Therefore, the light source device 30A of this embodiment can ensure the amount of blue fluorescence B and suppress a decrease in wavelength conversion efficiency. Furthermore, since the incidence of the yellow fluorescence Y on the second wavelength conversion element 52 is suppressed, the absorption of the yellow fluorescence Y in the second wavelength conversion element 52 is suppressed, and the decrease in the light amount of the yellow fluorescence Y can be suppressed.

[0092] [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, and therefore 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 30C of the third 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 30C 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 (not shown), and a fourth reflecting member (not shown).

[0094] In the light source device 30A of the first embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are bonded to each other via an optical adhesive. In contrast, in the light source device 30C of the present embodiment, a second reflecting member 82 is disposed between the first wavelength conversion element 51 and the second wavelength conversion element 52. The second reflecting member 82 reflects the first excitation light E1, the yellow fluorescence Y, the second excitation light E2, and the blue fluorescence B. The second reflecting member 82 is made of, for example, a metal film or a dielectric multilayer film. The other configurations of the light source device 30C are similar to those of the light source device 30A of the first embodiment.

[0095] (Effects of the third embodiment) In the present embodiment, yellow fluorescence Y propagates through the first light-guiding section 71, and blue fluorescence B propagates through the second light-guiding section 72, thereby achieving the same effects as in the first embodiment, such as reducing the loss of yellow fluorescence Y and blue fluorescence B and realizing a light source device 30C that is excellent in utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and that is capable of efficiently emitting white light LW.

[0096] In this embodiment, the second reflecting member 82 is provided between the first wavelength conversion element 51 and the second wavelength conversion element 52. Therefore, when the fluorescence Y and B generated by one of the wavelength conversion elements 51 and 52 reaches the rear surface 51b and 52b of the wavelength conversion element 51 and 52, they are reflected by the second reflecting member 82 and do not enter the other wavelength conversion element 52 and 51. As a result, while the fluorescence B3 and B4 shown in FIG. 3 of the first embodiment enter the first wavelength conversion element 51, as shown in FIG. 6, the fluorescence B3 and B4 of this embodiment are reflected by the second reflecting member 82 and do not enter the first wavelength conversion element 51. Therefore, the amount of blue fluorescence B can be secured and a decrease in wavelength conversion efficiency can be suppressed. Furthermore, because the yellow fluorescence Y is reflected by the second reflecting member 82 and does not enter the second wavelength conversion element 52, the absorption of the yellow fluorescence Y can be reduced, and a decrease in the amount of yellow fluorescence Y can be suppressed.

[0097] [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 similar to that of the first embodiment, and therefore a description of the basic configuration of the light source device will be omitted. 7 is a cross-sectional view of a light source device 30D of the fourth embodiment cut along the XY plane. In Fig. 7, components common to those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0098] As shown in Figure 7, the light source device 30D 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 scattering layer 86, a third reflecting member (not shown), and a fourth reflecting member (not shown).

[0099] In the light source device 30A of the first embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are bonded to each other via an optical adhesive. In contrast, in the light source device 30D of the present embodiment, a scattering layer 86 is disposed between the first wavelength conversion element 51 and the second wavelength conversion element 52. The scattering layer 86 reflects the first excitation light E1, the yellow fluorescence Y, the second excitation light E2, and the blue fluorescence B, and changes the emission angles of each light. The scattering layer 86 is made of a scattering material containing, for example, barium sulfate. The other configurations of the light source device 30D are similar to those of the light source device 30A of the first embodiment.

[0100] (Effects of the fourth embodiment) In the present embodiment, yellow fluorescence Y propagates through the first light-guiding section 71, and blue fluorescence B propagates through the second light-guiding section 72, thereby achieving the same effects as in the first embodiment, such as reducing the loss of yellow fluorescence Y and blue fluorescence B and realizing a light source device 30D that is excellent in utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and realizing a light source device 30D that can efficiently emit white light LW.

[0101] In this embodiment, the scattering layer 86 is provided between the first wavelength conversion element 51 and the second wavelength conversion element 52. When the fluorescence Y or B generated by one of the wavelength conversion elements 51 or 52 reaches the rear surface 51b or 52b of the wavelength conversion element 51 or 52, the fluorescence Y or B is scattered and reflected by the scattering layer 86, changing the emission angle and making it less likely to enter the other wavelength conversion element 52 or 51. As a result, while the fluorescence B3 or B4 shown in FIG. 3 of the first embodiment enters the first wavelength conversion element 51, as shown in FIG. 7, the fluorescence B3 or B4 in this embodiment is scattered by the scattering layer 86 and enters the second light-transmissive member 74 without entering the first wavelength conversion element 51. The fluorescence B3 or B4 propagates through the second light-transmissive member 74 and is emitted to the outside. This ensures the light intensity of the blue fluorescence B and prevents a decrease in wavelength conversion efficiency. Furthermore, the yellow fluorescence Y is scattered by the scattering layer 86 and is less likely to enter the second wavelength conversion element 52. This reduces the absorption of the yellow fluorescence Y and prevents a decrease in the light intensity of the yellow fluorescence Y.

[0102] [Fifth embodiment] A fifth embodiment of the present invention will be described below with reference to FIGS. The basic configuration of the light source device of the fifth embodiment is the same as that of the first embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 8 is a perspective view of light source device 30E of the fifth embodiment. Fig. 9 is a cross-sectional view of light source device 30E taken along line IX-IX in Fig. 8. In Fig. 8 and Fig. 9, components common to those in the drawings used in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0103] As shown in Figures 8 and 9, the light source device 30E of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 51, a first optical layer 61, a second light source 42, a second wavelength conversion element 52, a second optical layer 62, a light guiding section 76, a first reflecting member 81, a third reflecting member (not shown), and a fourth reflecting member (not shown).

[0104] 9, in the light source device 30E of this embodiment, the first optical layer 61 is disposed on the surface 51a of the first wavelength conversion element 51. That is, the first optical layer 61 and the first wavelength conversion element 51 are in contact with each other. The second optical layer 62 is disposed on the surface 52a of the second wavelength conversion element 52. That is, the second optical layer 62 and the second wavelength conversion element 52 are in contact with each other.

[0105] The light guiding unit 76 is disposed between the first wavelength conversion element 51 and the second wavelength conversion element 52. The light guiding unit 76 is configured with an air layer 77. That is, the first wavelength conversion element 51 and the second wavelength conversion element 52 are disposed spaced apart from each other, and air exists between the first wavelength conversion element 51 and the second wavelength conversion element 52. The light guiding unit 76 guides the yellow fluorescence Y converted by the first wavelength conversion element 51 and the blue fluorescence B converted by the second wavelength conversion element 52. The second wavelength conversion element 52 is disposed on the opposite side of the first wavelength conversion element 51 from the first light source 41. A first reflecting member 81 is disposed in a region of the light guiding unit 76 on the first end face 51c side.

[0106] 8, in a planar view in the X-axis direction, which is the normal direction to the second end face 51d of the first wavelength conversion element 51, the extraction port 33k overlaps the first wavelength conversion element 51, the light guiding unit 76, and the second wavelength conversion element 52. Therefore, the second end face 51d of the first wavelength conversion element 51, the region of the light guiding unit 76 on the second end face 51d side, and the second end face 52d of the second wavelength conversion element 52 are exposed to the outside through the extraction port 33k. In the example of FIG. 8, the extraction port 33k also overlaps the first optical layer 61 and the second optical layer 62, but it does not have to overlap the first optical layer 61 and the second optical layer 62. The other configurations of the light source device 30E are similar to those of the light source device 30A of the first embodiment.

[0107] The behavior of light in the light source device 30E of this embodiment will be described below. 9, in the light source device 30E, the first excitation light E1 emitted from the first light source 41 passes through the first optical layer 61 and enters the first wavelength conversion element 51. When the first excitation light E1 enters 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.

[0108] The yellow fluorescence Y1 incident on the rear 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, travels through the air layer 77, and then is emitted to the outside from a region on the second end surface 51d side of the air layer 77. On the other hand, the yellow fluorescence Y2 incident on the rear surface 51b of the first wavelength conversion element 51 at an incident angle equal to or greater than the critical angle travels inside the first wavelength conversion element 51 while repeatedly being totally reflected by the rear surface 51b of the first wavelength conversion element 51 and reflected by the first optical layer 61, because the first wavelength conversion element 51 is made of a transparent phosphor and its traveling direction does not change.

[0109] The yellow fluorescence Y3 that travels through the air layer 77 toward the +X side and enters the second wavelength conversion element 52 travels through the air layer 77 while repeatedly reflected by the second optical layer 62 and the first optical layer 61, and then is emitted to the outside from a region on the second end surface 51d side of the air layer 77. The yellow fluorescence Y4 that travels through the air layer 77 toward the -X side and enters the second wavelength conversion element 52 travels through the air layer 77 while repeatedly reflected by the second optical layer 62 and the first optical layer 61, and then is reflected by the first reflecting member 81, and travels through the air layer 77 while repeatedly reflected again by the second optical layer 62 and the first optical layer 61, and then is emitted to the outside from a region on the second end surface 51d side of the air layer 77. Note that part of the yellow fluorescence Y3 and Y4 that enters the second wavelength conversion element 52 is absorbed by the phosphor included in the second wavelength conversion element 52 and is lost.

[0110] On the other hand, the second excitation light E2 emitted from the second light source 42 passes through the second optical layer 62 and enters the second wavelength conversion element 52. When the second excitation light E2 enters 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.

[0111] The blue fluorescence B1 incident on 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, travels through the air layer 77, and then is emitted to the outside from a region on the second end surface 52d side of the air layer 77. On the other hand, the blue fluorescence B2 incident on the back surface 52b of the second wavelength conversion element 52 at an incident angle equal to or greater than the critical angle travels inside the second wavelength conversion element 52 while repeatedly being totally reflected by the back surface 52b of the second wavelength conversion element 52 and reflected by the second optical layer 62, because the second wavelength conversion element 52 is made of a transparent phosphor and its traveling direction does not change.

[0112] Blue fluorescence B3 travels through the air layer 77 toward the -X side and enters the first reflecting member 81. After being reflected by the first reflecting member 81, the blue fluorescence B3 travels through the air layer 77 and is emitted to the outside from the region on the second end face 52d side of the air layer 77. After being emitted into the air layer 77, blue fluorescence B4 enters the first wavelength conversion element 51. The blue fluorescence B4 is converted into yellow fluorescence Y5 by the phosphor contained in the first wavelength conversion element 51 and is emitted to the outside.

[0113] As described above, the yellow fluorescence Y converted by the first wavelength conversion element 51 is emitted to the outside from the light guiding section 76 formed by the air layer 77 and the first wavelength conversion element 51. The blue fluorescence B converted by the second wavelength conversion element 52 is emitted to the outside from the light guiding section 76 formed by the air layer 77 and the second wavelength conversion element 52. That is, the yellow fluorescence Y converted by the first wavelength conversion element 51 and the blue fluorescence B converted by the second wavelength conversion element 52 travel through the light guiding section 76 and are emitted from a region on the second end surface 51d side of the light guiding section 76. In this way, the light source device 30E can emit white light LW containing the yellow fluorescence Y converted by the first wavelength conversion element 51 and the blue fluorescence B converted by the second wavelength conversion element 52 to the outside from the outlet 33k of the housing 31.

[0114] (Effects of the fifth embodiment) In the present embodiment, the yellow fluorescence Y and the blue fluorescence B propagate through the light-guiding section 76, which reduces loss of the yellow fluorescence Y and the blue fluorescence B and provides a light source device 30E that is excellent in utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and that is capable of efficiently emitting white light LW, thereby achieving the same effects as in the first embodiment.

[0115] In the first to fourth embodiments, the yellow fluorescence Y generated by the first wavelength conversion element 51 is mainly emitted from the region of the first light guide section 71 of the output port 33k, and the blue fluorescence B generated by the second wavelength conversion element 52 is mainly emitted from the region of the second light guide section 72 of the output port 33k. As described above, since the emission positions of the yellow fluorescence Y and the blue fluorescence B are different, there is a risk of color unevenness occurring in the optical system downstream of the light source device. In contrast, in this embodiment, the yellow fluorescence Y generated by the first wavelength conversion element 51 and the blue fluorescence B generated by the second wavelength conversion element 52 are emitted from the light guide section 76 that is common to both types of light. Therefore, the yellow fluorescence Y and the blue fluorescence B are mixed and emitted from the same location, which makes it possible to suppress color unevenness in the optical system downstream of the light source device 30E.

[0116] In the present embodiment, the light guide section 76 that guides the yellow fluorescence Y and the blue fluorescence B is configured with the air layer 77, and therefore the following effects can be obtained. 10 is a schematic diagram for explaining the operation of light source device 30E of this embodiment. The behavior of yellow fluorescence Y and the behavior of blue fluorescence B relative to the air layer 77 are substantially similar, but here, the behavior of blue fluorescence B relative to the air layer 77 will be illustrated and explained.

[0117] 10 , 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 light-transmitting 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 light-transmitting member 74. Here, if the material of the second wavelength conversion element 52 is SBCA and the material of the light-transmitting 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 light-transmitting member 74 is about 0.1 to 0.6, which is relatively small.

[0118] 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 light-transmitting member 74 travels in a direction nearly perpendicular to the interface K, i.e., in a direction that forms 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 light-transmitting member 74 opposite the interface K, and become leakage light B6. Alternatively, even if the blue fluorescence B5 becomes fluorescence B7 reflected by the surface 74b of the light-transmitting member 74, when it propagates through the light-transmitting member 74 in the X-axis direction and reaches the end surface 74d of the light-transmitting 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.

[0119] In contrast, when the air layer 77 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 air layer 77 is approximately 0.5 to 1.0, which is larger than the refractive index difference in the first to fourth embodiments. Therefore, the refraction angle β2 is larger than the refraction angle β1, and the blue fluorescence B8 incident on the air layer 77 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 light-transmitting member 74. As a result, the blue fluorescence B8 is more likely to be totally reflected when it reaches the interface between the air layer 77 and another substance, and is less likely to leak to the outside. Furthermore, in the present embodiment, the air layer 77 is open to the external space at the outlet 33k, and therefore 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 30E of the present embodiment can improve the extraction efficiency of the yellow fluorescence Y and the blue fluorescence B compared to the first to fourth embodiments.

[0120] Furthermore, according to the configuration of this embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are arranged apart from each other, so that it is possible to efficiently cool each of the wavelength conversion elements 51 and 52. As a result, it is possible to suppress a temperature rise of each of the wavelength conversion elements 51 and 52, and it is possible to maintain high wavelength conversion efficiency.

[0121] [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 fifth embodiment, and therefore 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, components common to those in the fifth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0122] 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 61, a second light source 42, a second wavelength conversion element 52, a second optical layer 62, a light guiding section 78, a first reflecting member 81, a third reflecting member (not shown), and a fourth reflecting member (not shown).

[0123] In the light source device 30E of the fifth embodiment, the light-guiding section 76 is formed of an air layer 77. In contrast, in the light source device 30F of the present embodiment, a light-transmitting member 79 is disposed in the light-guiding section 78. The light-transmitting member 79 transmits the first excitation light E1, the yellow fluorescence Y, the second excitation light E2, and the blue fluorescence B. Like the first light-transmitting member 73 of the first embodiment, the light-transmitting member 79 is made of a light-transmitting material such as borosilicate glass such as BK7, quartz, synthetic quartz, crystal, SiC, GaN, MgO, YAG, sapphire, or diamond. The other configurations of the light source device 30F are similar to those of the light source device 30E of the fifth embodiment.

[0124] The behavior of light in the light source device 30F is also substantially the same as that of the light source device 30E of the fifth embodiment. That is, the yellow fluorescence Y converted by the first wavelength conversion element 51 and the blue fluorescence B converted by the second wavelength conversion element 52 travel inside the light-transmitting member 79, which is the light-guiding section 78, and are emitted from the end face of the light-transmitting member 79 on the second end face 51d side.

[0125] (Effects of the sixth embodiment) In the present embodiment, the yellow fluorescence Y and the blue fluorescence B propagate through the light-guiding section 78, which reduces loss of the yellow fluorescence Y and the blue fluorescence B and provides a light source device 30F that is excellent in utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and that is capable of efficiently emitting white light LW, thereby achieving the same effects as in the first embodiment.

[0126] Furthermore, since the yellow fluorescence Y and the blue fluorescence B are mainly emitted from the light-guiding section 78, the occurrence of color unevenness in the optical system downstream of the light source device 30F can be suppressed, and since the wavelength conversion elements 51, 52 can be efficiently cooled, high wavelength conversion efficiency can be maintained, thereby achieving the same effects as in the fifth embodiment.

[0127] Furthermore, in the present embodiment, since the light guiding section 78 is made of a light-transmitting member 79, the difference in refractive index between each wavelength conversion element 51, 52 and the light guiding section 78 is smaller, and the critical angle at the interface between each wavelength conversion element 51, 52 and the light guiding section 78 is larger, compared to the fifth embodiment in which the light guiding section 76 is made of an air layer 77. This makes it difficult for the fluorescence Y and B generated by each wavelength conversion element 51, 52 to be totally reflected at the interface with the light guiding section 78, making it easier to extract the fluorescence Y and B into the light guiding section 78. Therefore, loss due to re-absorption of the fluorescence Y and B can be suppressed.

[0128] [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 sixth embodiment, and therefore 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, components common to those in Fig. 11 used in the sixth embodiment are given the same reference numerals, and description thereof will be omitted.

[0129] 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 51, a first optical layer 61, a second light source 42, a second wavelength conversion element 52, a second optical layer 62, a light guiding section 78, a third optical layer 63, a fourth optical layer 64, a first reflecting member 81, a third reflecting member (not shown), and a fourth reflecting member (not shown).

[0130] In this embodiment, a light-transmitting member 79 is disposed in the light-guiding section 78. The third optical layer 63 is disposed between the light-transmitting member 79 and the second wavelength conversion element 52. The third optical layer 63 has the optical property of transmitting the first excitation light E1 and the blue fluorescence B and reflecting the yellow fluorescence Y. Note that although the third optical layer 63 in this embodiment has the optical property of reflecting the second excitation light E2, it may also have the property of transmitting the second excitation light E2. The third optical layer 63 is configured, for example, by a dielectric multilayer film.

[0131] The fourth optical layer 64 is disposed between the light-transmitting member 79 and the first wavelength conversion element 51. The fourth optical layer 64 has the optical property of transmitting the yellow fluorescence Y and reflecting the first excitation light E1 and the blue fluorescence B. Note that although the fourth optical layer 64 of this embodiment has the optical property of reflecting the second excitation light E2, it may also have the property of transmitting the second excitation light E2. The fourth optical layer 64 is formed of, for example, a dielectric multilayer film. The other configurations of the light source device 30G are similar to those of the light source device 30F of the sixth embodiment.

[0132] (Effects of the Seventh Embodiment) In the present embodiment, the yellow fluorescence Y and the blue fluorescence B propagate through the light-guiding section 78, which reduces loss of the yellow fluorescence Y and the blue fluorescence B and provides a light source device 30G that is excellent in utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and that is capable of efficiently emitting white light LW, thereby achieving the same effects as in the first embodiment.

[0133] Furthermore, since the yellow fluorescence Y and the blue fluorescence B are mainly emitted from the light-guiding section 78, the occurrence of color unevenness in the optical system downstream of the light source device 30G can be suppressed, and since the wavelength conversion elements 51, 52 can be efficiently cooled, high wavelength conversion efficiency can be maintained, thereby achieving the same effects as in the fifth embodiment.

[0134] In the present embodiment, as in the sixth embodiment, the light guiding section 78 is made of a light-transmitting member 79. Therefore, compared to the fifth embodiment in which the light guiding section 76 is made of an air layer 77, the refractive index difference between each wavelength conversion element 51, 52 and the light guiding section 78 is smaller, and the critical angle at the interface between each wavelength conversion element 51, 52 and the light guiding section 78 is smaller. Furthermore, in the present embodiment, for example, yellow fluorescence Y3 traveling from the first wavelength conversion element 51 toward the second wavelength conversion element 52 is reflected by the third optical layer 63, and therefore does not enter the second wavelength conversion element 52 and be absorbed. Furthermore, blue fluorescence B4 traveling from the second wavelength conversion element 52 toward the first wavelength conversion element 51 is reflected by the fourth optical layer 64, and therefore does not enter the first wavelength conversion element 51 and be converted into yellow fluorescence Y. This reduces the absorption of yellow fluorescence Y when it enters the second wavelength conversion element 52, and reduces the absorption of blue fluorescence B when it enters the first wavelength conversion element 51, thereby improving the wavelength conversion efficiency compared to the sixth embodiment.

[0135] [Eighth embodiment] An eighth embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the eighth embodiment is the same as that of the seventh embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 13 is a cross-sectional view of a light source device 30H of the eighth embodiment cut along the XY plane. In Fig. 13, components common to those in Fig. 12 used in the seventh embodiment are given the same reference numerals, and description thereof will be omitted.

[0136] As shown in Figure 13, the light source device 30H of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 53, a first optical layer 61, a second light source 42, a second wavelength conversion element 54, a second optical layer 62, a light guiding section 78, a third optical layer 63, a fourth optical layer 64, a first reflecting member 81, a third reflecting member (not shown), and a fourth reflecting member (not shown).

[0137] In the light source device 30G of the seventh 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 30H of this 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 achieved 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 30H are similar to those of the light source device 30G of the seventh embodiment.

[0138] (Effects of the eighth embodiment) In the present embodiment, the yellow fluorescence Y and the blue fluorescence B propagate through the light-guiding section 78, which reduces loss of the yellow fluorescence Y and the blue fluorescence B and makes it possible to realize a light source device 30H that is excellent in utilization efficiency of the yellow fluorescence Y and the blue fluorescence B, and that is capable of efficiently emitting white light LW, thereby achieving the same effects as in the first embodiment.

[0139] Furthermore, since the yellow fluorescence Y and the blue fluorescence B are mainly emitted from the light-guiding section 78, the occurrence of color unevenness in the optical system downstream of the light source device 30H can be suppressed, and since the wavelength conversion elements 51, 52 can be efficiently cooled, high wavelength conversion efficiency can be maintained, thereby achieving the same effects as in the fifth embodiment.

[0140] Furthermore, in 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. 12 , since the wavelength conversion elements 51, 52 are made of transparent phosphors, the fluorescence Y, B is not scattered when propagating through the wavelength conversion elements 51, 52, and the traveling direction of the fluorescence Y, B is not changed. Therefore, the yellow fluorescence Y that is emitted from the first wavelength conversion element 51 and then re-enters the first wavelength conversion element 51 is reflected by the first optical layer 61 and then emitted again from the first wavelength conversion element 51. Therefore, part of the yellow fluorescence Y is absorbed by the phosphor while propagating through the first wavelength conversion element 51, resulting in loss.

[0141] In contrast to this, in the case of the present embodiment, since the first wavelength conversion element 53 is made of a phosphor having light-scattering properties, a lot of scattering occurs when the yellow fluorescence Y enters the first wavelength conversion element 53, and the traveling direction of the yellow fluorescence Y changes with each scattering. For this reason, as shown in Fig. 13 , for example, the yellow fluorescence Y1 that has passed through the fourth optical layer 64 and entered the first wavelength conversion element 53 is scattered by the first wavelength conversion element 53 and emitted to the light-transmitting member 79 in an angle-converted state, propagates inside the light-transmitting member 79, and then exits from the region on the second end face 53d side of the light-transmitting member 79.

[0142] The blue fluorescence B behaves in the same manner as the yellow fluorescence Y. For example, the blue fluorescence B1 that has passed through the third optical layer 63 and entered the second wavelength conversion element 54 is scattered by the second wavelength conversion element 54 and emitted to the light-transmitting member 79 in an angle-converted state, propagates through the light-transmitting member 79, and then emitted from the region on the second end face 54d side of the light-transmitting member 79. Thus, in the case of the present embodiment, there is almost no yellow fluorescence Y or blue fluorescence B propagating through the first wavelength conversion element 53 and the second wavelength conversion element 54.

[0143] As described above, in the present embodiment, the yellow fluorescence Y propagates through the light guiding unit 78 while being repeatedly scattered by the first wavelength conversion element 53 and reflected by the third optical layer 63, and is emitted from the region on the second end face 53d side of the light guiding unit 78. The blue fluorescence B propagates through the light guiding unit 78 while being repeatedly scattered by the second wavelength conversion element 54 and reflected by the fourth optical layer 64, and is emitted from the region on the second end face 54d side of the light guiding unit 78. As a result, the loss of the fluorescence Y and B when propagating 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 seventh embodiment. The light source device 30H of this embodiment achieves the highest wavelength conversion efficiency of all the embodiments.

[0144] In this embodiment, an example is shown in which a phosphor having light scattering properties is used for each wavelength conversion element 53, 54 in the light source device 30G of the seventh embodiment, but a phosphor having light scattering properties may also be used for each wavelength conversion element in the light source devices 30A to 30F of the other embodiments.

[0145] 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. With this configuration, even if the contact area between the first wavelength conversion element and the housing is small and many heat dissipation paths cannot be ensured, 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] Summary of this disclosure A summary of this disclosure is provided below.

[0150] (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, the second light, the third light, and the fourth 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 of ​​the first light guiding section on the second surface side and an area of ​​the second light guiding section on the fifth surface side, the second wavelength conversion element is disposed on the opposite side of the first wavelength conversion element from the first light source, the second light converted by the first wavelength conversion element travels through the first light guiding section and is emitted from a region on the third surface side of the first light guiding section, the fourth light converted by the second wavelength conversion element travels through the second light guiding section and is emitted from a region of the second light guiding section on the sixth surface side.

[0151] According to the configuration of Supplementary Note 1, the second light propagates through the first light guiding section, and the fourth light propagates through the second light guiding section, thereby realizing a light source device with little loss of the second light and the fourth light and excellent utilization efficiency of the second light and the fourth light. Also, a light source device capable of efficiently emitting combined light obtained by combining the second light and the fourth light can be realized.

[0152] (Appendix 2) 2. The light source device according to claim 1, wherein the first wavelength conversion element is bonded to the second wavelength conversion element.

[0153] According to the configuration of Supplementary Note 2, the first wavelength conversion element and the second wavelength conversion element can be handled as an integrated member, which makes it possible to facilitate the manufacturing process of the light source device.

[0154] (Appendix 3) 2. The light source device according to claim 1, wherein an air layer is disposed between the first wavelength conversion element and the second wavelength conversion element.

[0155] According to the configuration of Supplementary Note 3, the light converted by one wavelength conversion element is likely to be totally reflected at the interface between the wavelength conversion element and the air layer, and is therefore unlikely to be incident on the other wavelength conversion element. Therefore, when the light converted by one wavelength conversion element is incident on the other wavelength conversion element, absorption is suppressed, and a decrease in wavelength conversion efficiency can be suppressed.

[0156] (Appendix 4) A light source device as described in Appendix 1, wherein a second reflecting member that reflects the first light, the second light, the third light, and the fourth light is arranged between the first wavelength conversion element and the second wavelength conversion element.

[0157] According to the configuration of Supplementary Note 4, the light converted by one wavelength conversion element is reflected by the second reflecting member and does not enter the other wavelength conversion element, thereby suppressing absorption of the light converted by one wavelength conversion element when it enters the other wavelength conversion element, and thus suppressing a decrease in wavelength conversion efficiency.

[0158] (Appendix 5) 2. The light source device according to claim 1, wherein a scattering layer that reflects incident light and changes the exit angle of the light is disposed between the first wavelength conversion element and the second wavelength conversion element.

[0159] According to the configuration of Supplementary Note 5, the light converted by one wavelength conversion element is reflected by the scattering layer and the exit angle changes, so that the light is prevented from entering the other wavelength conversion element. This reduces absorption of the light converted by one wavelength conversion element when it enters the other wavelength conversion element, and can prevent a decrease in wavelength conversion efficiency.

[0160] (Appendix 6) further comprising a third reflecting member and a fourth reflecting member that reflect the first light, the second light, the third light, and the fourth light, 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 third reflecting member is disposed in an area on the seventh surface side of the first light guiding section and an area on the ninth surface side of the second light guiding section, The light source device according to any one of claims 1 to 5, wherein the fourth reflecting member is arranged in the area on the eighth surface side of the first light guide section and the area on the tenth surface side of the second light guide section.

[0161] According to the configuration of Supplementary Note 6, the third reflecting member and the fourth reflecting member can increase the conversion efficiency from the first light to the second light and from the third light to the fourth light. Also, loss of the second light and the fourth light from the seventh, eighth, ninth, and tenth surfaces can be reduced.

[0162] (Appendix 7) 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 emitted from the region on the third surface side of the first light guiding section and the fourth light emitted from the region on the sixth surface side of the second light guiding section are extracted to the outside, 7. The light source device according to claim 1, wherein, when viewed in a plane in a normal direction of the third surface of the first wavelength conversion element, the outlet overlaps with the first light guiding section, the first wavelength conversion element, the second light guiding section, and the second wavelength conversion element.

[0163] According to the configuration of Appendix 7, 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 propagating through the first light guiding section and the first wavelength conversion element and the fourth light propagating through the second light guiding section and the second wavelength conversion element can be extracted to the outside through the extraction port of the housing.

[0164] (Appendix 8) 8. 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.

[0165] According to the configuration of Appendix 8, 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 is increased without increasing the size of each wavelength conversion element, thereby improving the conversion efficiency of the second light and the fourth light, and the second light and the fourth light can be efficiently extracted to the outside.

[0166] (Appendix 9) 8. 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.

[0167] According to the configuration of Supplementary Note 9, 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, so that loss of the second light is suppressed and 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 loss of the fourth light is suppressed and extraction efficiency of the fourth light can be further increased.

[0168] (Appendix 10) 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 9, wherein the blue fluorescence propagates through the second light guide section while being repeatedly scattered by the second wavelength conversion element and reflected by the second optical layer, and is emitted from the area on the sixth surface side of the second light guide section.

[0169] According to the configuration of Supplementary Note 10, yellow fluorescence generated inside the first wavelength conversion element can be efficiently extracted to the outside from the region on the third surface side of the first light guiding unit, and blue fluorescence generated inside the second wavelength conversion element can be efficiently extracted to the outside from the region on the sixth surface side of the second light guiding unit.

[0170] (Appendix 11) 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 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 light guiding section disposed between the first wavelength conversion element and the second wavelength conversion element, which guides the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element; a first reflecting member that reflects the first light, the second light, the third light, and the fourth 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 a second surface and a third surface 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 a fifth surface and a sixth surface that intersect with the fourth surface and face in opposite directions to each other, the second wavelength conversion element is disposed on the opposite side of the first wavelength conversion element from the first light source, the first reflecting member is disposed in an area on the second surface side of the light guiding section, the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element travel through the light guiding section and are emitted from a region on the third surface side of the light guiding section.

[0171] According to the configuration of Supplementary Note 11, since the second light and the fourth light propagate through the light guide, a light source device with little loss of the second light and the fourth light and excellent utilization efficiency of the second light and the fourth light can be realized. Also, a light source device capable of efficiently emitting combined light obtained by combining the second light and the fourth light can be realized.

[0172] (Appendix 12) the light guide portion is an air layer, The light source device described in Appendix 11, wherein the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element travel through the air layer and are emitted from the area on the third surface side of the air layer.

[0173] According to the configuration of Supplementary Note 12, the second light and the fourth light travel in a direction that forms a smaller angle with respect to the longitudinal direction of the first wavelength conversion element and the second wavelength conversion element than in the configuration in which the second light and the fourth light are incident on the light-transmitting member. As a result, when the second light reaches the interface between the air layer and another substance, it is more likely to be totally reflected and less likely to leak to the outside. This can increase the extraction efficiency of the second light and the fourth light.

[0174] (Appendix 13) 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 the region on the third surface side of the light guiding section are extracted to the outside, A light source device as described in Appendix 12, wherein, when viewed in a plane in the normal direction of the third surface of the first wavelength conversion element, the outlet overlaps with the first wavelength conversion element, the light guiding section, and the second wavelength conversion element.

[0175] According to the configuration of Appendix 13, 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 propagating through the light guide and the first wavelength conversion element and the fourth light propagating through the light guide and the second wavelength conversion element can be extracted to the outside through the extraction opening of the housing.

[0176] (Appendix 14) a light-transmitting member that transmits the first light, the second light, the third light, and the fourth light is disposed in the light-guiding section; The light source device described in Appendix 11, wherein the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element travel inside the translucent member and are emitted from the end face of the translucent member on the third surface side.

[0177] According to the configuration of Supplementary Note 14, since a light-transmitting member is disposed in the light guiding section, the difference in refractive index between each wavelength conversion element and the light guiding section is smaller than in a configuration in which the light guiding section is constituted by an air layer, and the critical angle at the interface between each wavelength conversion element and the light guiding section is smaller, which makes it easier to extract the second light and the fourth light generated by each wavelength conversion element into the light guiding section and reduces losses due to re-absorption of the second light and the fourth light.

[0178] (Appendix 15) a third optical layer disposed between the light-transmitting member and the second wavelength conversion element, the third optical layer transmitting the first light and the fourth light and reflecting the second light; a fourth optical layer disposed between the light-transmitting member and the first wavelength conversion element, the fourth optical layer transmitting the second light and reflecting the first light and the fourth light; 15. The light source device of claim 14, further comprising:

[0179] According to the configuration of Supplementary Note 15, the second light traveling toward the second wavelength conversion element is reflected by the third optical layer, and therefore does not enter the second wavelength conversion element and be absorbed. Also, the first light and the fourth light traveling toward the first wavelength conversion element are reflected by the fourth optical layer, and therefore do not enter the first wavelength conversion element and be absorbed. This suppresses the absorption of the second light when it enters the second wavelength conversion element, and the absorption of the fourth light when it enters the first wavelength conversion element, and can improve the wavelength conversion efficiency.

[0180] (Appendix 16) 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 the region on the third surface side of the light guiding section are extracted to the outside, 16. The light source device of claim 14, wherein, when viewed in a plane in the normal direction of the third surface of the first wavelength conversion element, the outlet overlaps with the first wavelength conversion element, the translucent member, and the second wavelength conversion element.

[0181] According to the configuration of Appendix 16, 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 propagating through the translucent member and the first wavelength conversion element and the fourth light propagating through the translucent member and the second wavelength conversion element can be extracted to the outside through the extraction opening of the housing.

[0182] (Appendix 17) further comprising a third reflecting member and a fourth reflecting member that reflect the first light, the second light, the third light, and the fourth light, 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 third reflecting member is disposed in an area on the seventh surface side of the light guiding section, 17. The light source device according to claim 11, wherein the fourth reflecting member is disposed in an area on the eighth surface side of the light guiding section.

[0183] According to the configuration of Supplementary Note 17, the third reflecting member and the fourth reflecting member can increase the conversion efficiency from the first light to the second light and from the third light to the fourth light. Also, loss of the second light and the fourth light from the seventh, eighth, ninth, and tenth surfaces can be reduced.

[0184] (Appendix 18) 18. The light source device according to claim 11, wherein the first wavelength conversion element and the second wavelength conversion element are made of a transparent phosphor.

[0185] According to the configuration of Appendix 18, 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.

[0186] (Appendix 19) 18. The light source device according to claim 11, wherein the first wavelength conversion element and the second wavelength conversion element are made of a phosphor having light scattering properties.

[0187] According to the configuration of Supplementary Note 19, the second light generated inside the first wavelength conversion element is efficiently emitted to the light guiding portion and propagates through the light guiding portion, 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 light guiding portion and propagates through the light guiding portion, so that the loss of the fourth light is suppressed and the extraction efficiency of the fourth light can be further increased.

[0188] (Appendix 20) 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 second optical layer reflects the second light; the yellow fluorescence propagates through the light guiding unit while being repeatedly scattered by the first wavelength conversion element and reflected by the second optical layer, and is emitted from a region of the light guiding unit on the third surface side, The light source device described in Appendix 19, wherein the blue fluorescence propagates through the light guiding section while being repeatedly scattered by the second wavelength conversion element and the first wavelength conversion element, and is emitted from the area on the third surface side of the light guiding section.

[0189] According to the configuration of Supplementary Note 20, yellow fluorescence generated inside the first wavelength conversion element can be efficiently extracted to the outside from the region on the third surface side of the light guiding unit, and blue fluorescence generated inside the second wavelength conversion element can be efficiently extracted to the outside from the region on the third surface side of the light guiding unit.

[0190] (Appendix 21) A light source device according to any one of Supplementary Note 1 to Supplementary Note 10; 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

[0191] According to the configuration of Supplementary Note 21, 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.

[0192] (Appendix 22) A light source device according to any one of Supplementary Note 11 to Supplementary Note 20; 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

[0193] According to the configuration of Supplementary Note 22, 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]

[0194] 10...Projector, 30A, 30B, 30C, 30D, 30E, 30F, 30G, 30H...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 (9th surface), 52f...second side surface (10th surface), 61...first optical layer, 62...second optical layer, 63...third optical layer, 64...fourth optical layer, 71...first light guiding section, 73...first light-transmissive member, 72...second light guiding section, 74...second light-transmissive member, 76, 78...light guiding section, 77...air layer, 79...light-transmissive member, 81...first reflecting member, 82...second reflecting member, 83...third reflecting member, 84...fourth reflecting member, 400B, 400G, 400R...light 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, the second light, the third light, and the fourth 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 of ​​the first light guiding section on the second surface side and an area of ​​the second light guiding section on the fifth surface side, the second wavelength conversion element is disposed on the opposite side of the first wavelength conversion element from the first light source, the second light converted by the first wavelength conversion element travels through the first light guiding section and is emitted from a region on the third surface side of the first light guiding section, The fourth light converted by the second wavelength conversion element travels through the second light guiding section and is emitted from a region on the sixth surface side of the second light guiding section.

2. The light source device according to claim 1 , wherein the first wavelength conversion element is bonded to the second wavelength conversion element.

3. The light source device according to claim 1 , wherein an air layer is disposed between the first wavelength conversion element and the second wavelength conversion element.

4. 2. The light source device according to claim 1, wherein a second reflecting member that reflects the first light, the second light, the third light, and the fourth light is disposed between the first wavelength conversion element and the second wavelength conversion element.

5. The light source device according to claim 1 , further comprising a scattering layer disposed between the first wavelength conversion element and the second wavelength conversion element, the scattering layer reflecting incident light and changing the exit angle of the light.

6. a third reflecting member and a fourth reflecting member that reflect the first light, the second light, the third light, and the fourth light, 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 third reflecting member is disposed in an area of ​​the first light guiding section on the seventh surface side and an area of ​​the second light guiding section on the ninth surface side, 6. The light source device according to claim 1, wherein the fourth reflecting member is disposed in an area on the eighth surface side of the first light guiding section and an area on the tenth surface side of the second light guiding section.

7. 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 emitted from the region on the third surface side of the first light guiding section and the fourth light emitted from the region on the sixth surface side of the second light guiding 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 third surface of the first wavelength conversion element, the outlet overlaps with the first light guiding section, the first wavelength conversion element, the second light guiding section, and the second wavelength conversion element.

8. 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.

9. 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.

10. 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, 10. The light source device according to claim 9, wherein the blue fluorescence propagates through the second light guiding section while being repeatedly scattered by the second wavelength conversion element and reflected by the second optical layer, and is emitted from a region on the sixth surface side of the second light guiding section.

11. 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 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 light guiding section disposed between the first wavelength conversion element and the second wavelength conversion element, which guides the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element; a first reflecting member that reflects the first light, the second light, the third light, and the fourth 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 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 a fifth surface and a sixth surface that intersect with the fourth surface and face in opposite directions to each other, the second wavelength conversion element is disposed on the opposite side of the first wavelength conversion element from the first light source, the first reflecting member is disposed in an area on the second surface side of the light guiding section, the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element travel through the light guiding section and are emitted from a region on the third surface side of the light guiding section.

12. the light guide portion is an air layer, The light source device according to claim 11, wherein the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element travel through the air layer and are emitted from a region on the third surface side of the air layer.

13. 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 the region on the third surface side of the light guiding section are extracted to the outside, 13. The light source device according to claim 12, wherein, when viewed in a plane in a normal direction of the third surface of the first wavelength conversion element, the extraction port overlaps with the first wavelength conversion element, the light guiding portion, and the second wavelength conversion element.

14. a light-transmitting member that transmits the first light, the second light, the third light, and the fourth light is disposed in the light guide portion; 12. The light source device according to claim 11, wherein the second light converted by the first wavelength conversion element and the fourth light converted by the second wavelength conversion element travel inside the translucent member and are emitted from an end face on the third surface side of the translucent member.

15. a third optical layer disposed between the light-transmitting member and the second wavelength conversion element, the third optical layer transmitting the first light and the fourth light and reflecting the second light; a fourth optical layer disposed between the light-transmitting member and the first wavelength conversion element, the fourth optical layer transmitting the second light and reflecting the first light and the fourth light; The light source device of claim 14 further comprising:

16. 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 the region on the third surface side of the light guiding section are extracted to the outside, 15. The light source device according to claim 14, wherein, when viewed in a plane in a normal direction of the third surface of the first wavelength conversion element, the extraction port overlaps with the first wavelength conversion element, the translucent member, and the second wavelength conversion element.

17. a third reflecting member and a fourth reflecting member that reflect the first light, the second light, the third light, and the fourth light, 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 third reflecting member is disposed in an area on the seventh surface side of the light guiding section, The light source device according to claim 11 , wherein the fourth reflecting member is disposed in an area of ​​the light guiding section on the eighth surface side.

18. 17. The light source device according to claim 11, wherein the first wavelength conversion element and the second wavelength conversion element are made of a transparent phosphor.

19. 17. The light source device according to claim 11, wherein the first wavelength conversion element and the second wavelength conversion element are made of a phosphor having light scattering properties.

20. 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 second optical layer reflects the second light; the yellow fluorescence propagates through the light guiding unit while being repeatedly scattered by the first wavelength conversion element and reflected by the second optical layer, and is emitted from a region of the light guiding unit on the third surface side, 20. The light source device according to claim 19, wherein the blue fluorescence propagates through the light guiding section while being repeatedly scattered by the second wavelength conversion element and the first wavelength conversion element, and is emitted from a region on the third surface side of the light guiding section.

21. 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

22. a light source device according to any one of claims 11 to 16; 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

Images