Light source device and projector

Abstract

To provide a light source device and a projector excellent in light utilization efficiency.SOLUTION: The light source device according to the present disclosure includes the first light source configured to emit the first light beam, the first wavelength conversion element configured to convert the first light beam into the second light beam, the first optical layer configured to transmit the first light beam and reflect the second light beam, the light guide section configured to guide the second light beam, the second wavelength conversion element configured to convert the first light beam into the third light beam, the second optical layer configured to reflect the second light beam and the third light beam, and the first reflecting member. The first wavelength converter has the first surface on which the first light is incident via the first optical layer and the second and third surfaces that intersect the first surface and face away from each other, the first reflection member is disposed in a region of the light guide section that is the region facing the second surface, and the second light and the third light travel through the light guide section and exit via a region of the light guide section that is the region facing the third surface.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

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

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

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

[0005] In order to solve the above problem, a light source device according to one aspect of the present invention includes a first light source that emits first light in a first wavelength band, a first wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band, a first optical layer that is disposed between the first light source and the first wavelength conversion element and that transmits the first light and reflects the second light, a light guide portion that is disposed on the opposite side of the first wavelength conversion element from the first optical layer and that guides the second light converted by the first wavelength conversion element, and a light guide portion that is disposed on the opposite side of the first wavelength conversion element from the first wavelength conversion element and that converts the first light incident via the first wavelength conversion element and the light guide portion into third light of a third wavelength different from the first wavelength. a second wavelength conversion element that converts the first light into the second light; a second optical layer that is arranged on the opposite side of the light guiding section from the second wavelength conversion element and that reflects the second light and the third light; and a first reflecting member that reflects the first light, the second light, and the third light, wherein 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 opposite each other, and the first reflecting member is arranged in an area on the second surface side of the light guiding section, and the second light converted by the first wavelength conversion element and the third 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.

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

[0007] [Figure 1] FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the light source device of the 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] FIG. 2 is a plan view of the light source device viewed from the +X side to the −X side. [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 cross-sectional view of a light source device according to a fifth embodiment. [Figure 9] FIG. 10 is a cross-sectional view of a light source device according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

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

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

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

[0012] In the following, the drawings will be described using an XYZ Cartesian coordinate system as necessary. The Z axis is an axis along the up-down direction of the projector 1. The X axis is an axis parallel to the optical axis AX1 of the first illumination device 20 and the optical axis AX2 of the second illumination device 21. The Y axis is an axis perpendicular to the X and Z axes. The optical axis AX1 of the first illumination device 20 is the central axis of the fluorescent light Y emitted from the first illumination device 20. The optical axis AX2 of the second illumination device 21 is the central axis of the blue light LB emitted from the second illumination device 21. 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. Furthermore, when the two directions along the X axis are referred to collectively without distinction, they are referred to as the X-axis direction; when the two directions along the Y axis are referred to collectively without distinction, they are referred to as the Y-axis direction; and when the two directions along the Z axis are referred to collectively without distinction, they are referred to as the Z-axis direction.

[0013] The color separation optical system 3 separates the yellow illumination light WL emitted from the first lighting device 20 into red light LR and green light LG. The color separation optical system 3 includes a dichroic mirror 7, a first reflecting mirror 8a, and a second reflecting mirror 8b.

[0014] The dichroic mirror 7 separates the illumination light WL into red light LR and green light LG. The dichroic mirror 7 transmits the red light LR and reflects the green light LG. The second reflecting mirror 8b is disposed in the optical path of the green light LG. The second reflecting mirror 8b reflects the green light LG reflected by the dichroic mirror 7 toward the optical modulation device 4G. The first reflecting mirror 8a is disposed in the optical path of the red light LR. The first reflecting mirror 8a reflects the red light LR transmitted through the dichroic mirror 7 toward the optical modulation device 4R.

[0015] On the other hand, the blue light LB emitted from the second illumination device 21 is reflected by the reflecting mirror 9 toward the light modulation device 4B.

[0016] The configuration of the second illumination device 21 will be described below. The second illumination device 21 includes a light source unit 44, a condenser lens 45, a diffuser plate 46, a rod lens 86, and a relay lens 87. The light source unit 44 is configured with at least one semiconductor laser. The light source unit 44 emits blue light LB made of laser light. Note that the light source unit 44 is not limited to a semiconductor laser, and may be configured with an LED that emits blue light.

[0017] The condenser lens 45 is composed of a convex lens. The condenser lens 45 causes the blue light LB emitted from the light source unit 44 to enter the diffuser plate 46 in a substantially condensed state. The diffuser plate 46 diffuses the blue light LB emitted from the condenser lens 45 with a predetermined degree of diffusion, thereby generating blue light LB having a substantially uniform luminous intensity distribution similar to that of the illumination light WL emitted from the first lighting device 20. The diffuser plate 46 may be, for example, frosted glass made of optical glass.

[0018] The blue light LB diffused by the diffuser plate 46 is incident on the rod lens 86. The rod lens 86 has a rectangular columnar shape extending along the optical axis AX2 of the second illumination device 21. The rod lens 86 has a light incident end surface 86a at one end and a light exit end surface 86b at the other end. The diffuser plate 46 is fixed to the light incident end surface 86a of the rod lens 86 via an optical adhesive (not shown). It is desirable that the refractive index of the diffuser plate 46 and the refractive index of the rod lens 86 match as closely as possible.

[0019] The blue light LB propagates through the rod lens 86 while being totally reflected, and is emitted from the light emitting end surface 86b with an increased uniformity of illuminance distribution. The blue light LB emitted from the rod lens 86 is incident on a relay lens 87. The relay lens 87 causes the blue light LB, whose uniformity of illuminance distribution has been increased by the rod lens 86, to be incident on a reflecting mirror 9.

[0020] The shape of the light exit end surface 86b of the rod lens 86 is a rectangle that is roughly similar to the shape of the image forming area of ​​the light modulation device 4B, so that the blue light LB exiting from the rod lens 86 is efficiently incident on the image forming area of ​​the light modulation device 4B.

[0021] The light modulation device 4R modulates the red light LR according to image information to form image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to image information to form image light corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to image information to form image light corresponding to the blue light LB.

[0022] Each of the light modulation devices 4R, 4G, and 4B uses, for example, a transmissive liquid crystal panel. Polarizing plates (not shown) are disposed on the entrance and exit sides of the liquid crystal panels. The polarizing plates allow only linearly polarized light in a specific direction to pass through.

[0023] A field lens 10R is disposed on the incident side of the optical modulation device 4R. A field lens 10G is disposed on the incident side of the optical modulation device 4G. A field lens 10B is disposed on the incident side of the optical modulation device 4B. The field lens 10R collimates the chief ray of the red light LR incident on the optical modulation device 4R. The field lens 10G collimates the chief ray of the green light LG incident on the optical modulation device 4G. The field lens 10B collimates the chief ray of the blue light LB incident on the optical modulation device 4B.

[0024] The light combining element 5 receives the image lights emitted from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, 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 6. The light combining element 5 may be, for example, a cross dichroic prism.

[0025] The projection optical device 6 is composed of a plurality of projection lenses. The projection optical device 6 enlarges and projects the image light combined by the light combining element 5 onto the screen SCR, thereby displaying a color image on the screen SCR.

[0026] Next, the configuration of the first illumination device 20 will be described. The first 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. Fig. 2 is a cross-sectional view of the 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.

[0027] As shown in Figures 2 and 3, 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 light-guiding section 71, a second light source 42, a second wavelength conversion element 52, a second optical layer 62, a first reflecting member 81, a third reflecting member 83, and a fourth reflecting member 84.

[0028] 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 light guide 71, the first wavelength conversion element 51, the second light source 42, the second optical layer 62, 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 lid 33 has a box-like shape with one side open, and has 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 opening 33K.

[0029] The bottom plate portion 32 is disposed along the XZ plane and has a recess that houses 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 a surface located on the +Y side of the base portion 32a.

[0030] The bottom plate portion 32 is connected to the second light source 42 and the second wavelength conversion element 52 in a manner that allows heat transfer. Therefore, 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.

[0031] 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.

[0032] 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 light guide 71 via the third reflecting member 83 and the fourth reflecting member 84 in a heat-transferable manner. For this reason, the lid 33 is desirably made of a material having a predetermined strength and high thermal conductivity, similar to the bottom plate 32. 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 6061 series is desirably used.

[0033] According to this configuration, heat from the first wavelength conversion element 51, the light guiding section 71, 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, the light guiding section 71, 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.

[0034] The bottom plate 32 and the lid 33 are arranged so that their sidewalls abut against each other. 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 way, in the light source device 30A, the components of the first light source 41, the first optical layer 61, the light guide 71, the first wavelength conversion element 51, the second light source 42, the second optical layer 62, 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.

[0035] The housing 31 has an outlet 31K for extracting to the outside the yellow illumination light WL emitted from the light-guiding unit 71. The outlet 31K is an opening defined by an opening 33K provided in the second side wall 33d of the lid 33 and a part of the frame 32b of the bottom plate 32.

[0036] Fig. 4 is a plan view of the light source device 30A viewed from the +X side to the -X side. That is, Fig. 4 is a plan view when viewed in the X-axis direction, which is the normal direction of the second end surface 51d along the YZ plane of the first wavelength conversion element 51. As shown in Fig. 4, the extraction port 31K overlaps the light guiding unit 71. That is, the extraction port 31K has a shape that covers the first optical layer 61, the first wavelength conversion element 51, the second wavelength conversion element 52, and the second optical layer 62, and exposes the light guiding unit 71 to the inside. Light source device 30A of this embodiment can efficiently extract fluorescence Y, Y1 that has propagated inside light guide section 71 via outlet 31K of housing 31 as yellow illumination light WL. The outlet 31K may be closed by a cover made of a light-transmitting material, and the light guide portion 71 may not be exposed to the outside.

[0037] 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 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 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 excitation light rays, toward the first wavelength conversion element 51. The first excitation light E1 of this embodiment corresponds to an example of the "first light in the first wavelength band" of the present invention.

[0038] 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. 3.

[0039] 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. The 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 light guide 71. The front surface 51a in this embodiment corresponds to an example of the "first surface" of the present invention.

[0040] As shown in FIG. 2, 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 an example of the “second surface” in the present invention, and the second end face 51d of this embodiment corresponds to an example of the “third surface” in the present invention.

[0041] 3, the first side surface 51e and the second side surface 51f intersect the front surface 51a and the back surface 51b and 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 an example of the "fourth surface" of the present invention, and the second side surface 51f of this embodiment corresponds to an example of the "fifth surface" of the present invention.

[0042] 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.

[0043] The first excitation light E1 emitted from the first light source 41 and transmitted through the first optical layer 61 is incident on the surface 51a of the first wavelength conversion element 51. 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 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 an example of the "second light" of the present invention.

[0044] In this specification, the transparent phosphor refers to a phosphor having a total light transmittance of 80% or more for fluorescent light. The transparent phosphor constituting the first wavelength conversion element 51 may be a transparent single crystal or polycrystalline body having a total light transmittance of 80% or more, such as a YAG ceramic phosphor obtained by sintering a plurality of YAG phosphor particles. The first wavelength conversion element 51 made of such a material converts the first excitation light E1 into yellow fluorescence Y.

[0045] 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 fluorescence Y. The first optical layer 61 is made of, for example, a dielectric multilayer film. The first optical layer 61 is provided on a surface of the first wavelength conversion element 51 facing the first light source 41.

[0046] The light guiding section 71 is disposed between the first optical layer 61 and the first wavelength conversion element 51. The light guiding section 71 guides the fluorescence Y and Y1 converted by the first wavelength conversion element 51 and the second wavelength conversion element 52, as will be described later. In the present embodiment, a first light-transmissive member 73 is disposed in the light guiding section 71.

[0047] 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 excitation light E and the fluorescence Y and Y1. The first light-transmissive member 73 has a plate-like shape extending along the X-axis. As shown in FIG. 3 , 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.

[0048] The thermal conductivity of the first light-transmissive member 73 is desirably greater than the thermal conductivity of the first wavelength conversion element 51 and the second wavelength conversion element 52. 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 and the second wavelength conversion element 52 is efficiently conducted to the first light-transmissive member 73, thereby suppressing a temperature rise in the first wavelength conversion element 51 and the second wavelength conversion element 52. This makes it possible to suppress a decrease in conversion efficiency due to a temperature rise in the first wavelength conversion element 51 and the second wavelength conversion element 52.

[0049] 2, the second light source 42 has a plurality of second light-emitting elements 421. The plurality of second light-emitting elements 421 are respectively mounted on the bottom plate portion 32 of the housing 31. The number of second light-emitting elements 421 is not particularly limited. Like the first light-emitting element 411 of the first light source 41, the second light-emitting element 421 emits a first excitation light beam in a first wavelength band. The plurality of second light-emitting elements 421 are arranged along the X-axis direction, which is the longitudinal direction of the second wavelength conversion element 52.

[0050] The second light source 42 is disposed on the opposite side (-Y side) of the light-guiding section 71 with respect to the second wavelength conversion element 52 described later. Based on this configuration, the second light source 42 emits second excitation light E2 of a first wavelength band consisting of a plurality of blue excitation light rays toward the second wavelength conversion element 52. The second excitation light E2 of this embodiment corresponds to an example of the "first light of a first wavelength band" of the present invention.

[0051] 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 light guiding section 71 from the first wavelength conversion element 51. The second wavelength conversion element 52 has a columnar shape extending along the X-axis and has six faces. The sides of the second wavelength conversion element 52 extending along the X-axis are longer than the sides extending along the Y-axis and the Z-axis. The X-axis direction corresponds to the longitudinal direction of the second wavelength conversion element 52. The Y-axis direction is a direction parallel to the shortest side of the 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. 3.

[0052] 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 one side, or the -Y side, in the Y axis direction. The back surface 52b is located on the other side, or the +Y side, in the Y axis direction.

[0053] 2, 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 one side, that is, the -X side, in the X-axis direction. The second end face 52d is located on the other side, that is, the +X side, in the X-axis direction.

[0054] 3, 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.

[0055] The second wavelength conversion element 52 converts the first excitation light E1 emitted from the first light source 41 and transmitted through the first optical layer 61, the first wavelength conversion element 51, and the light-guiding section 71, and the second excitation light E2 emitted from the second light source 42 and transmitted through the second optical layer 62, into yellow fluorescence Y1 of a third wavelength band different from the first wavelength band. The first excitation light E1 is incident on the back surface 52b of the second wavelength conversion element 52, and the second excitation light E2 is incident on the front surface 52a of the second wavelength conversion element 52.

[0056] In this embodiment, the second wavelength conversion element 52 is made of the same material as the first wavelength conversion element 51. Therefore, the third wavelength band of the fluorescence Y1 is, for example, a yellow wavelength band of 490 to 750 nm, and the center wavelength of the third wavelength band is 550 nm, which is equal to the center wavelength of the second wavelength band. The yellow fluorescence Y1 in this embodiment corresponds to an example of the "third light" of the present invention. The second wavelength band and the third wavelength band may be different from each other. For example, the center wavelength of the second wavelength band may be relatively closer to blue, and the center wavelength of the third wavelength band may be relatively closer to green.

[0057] 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 is disposed on the opposite side of the second wavelength conversion element 52 from the light guide section 71, and has the optical property of transmitting the second excitation light E2 and reflecting the fluorescence Y, Y1. The second optical layer 62 is formed of, for example, a dielectric multilayer film. The second optical layer 62 is provided on the surface of the second wavelength conversion element 52 facing the second light source 42.

[0058] 2, the first reflecting member 81 is disposed on the −X side of the first light source 41, the first optical layer 61, the light guide 71, the first wavelength conversion element 51, the second wavelength conversion element 52, the second optical layer 62, and the second light source 42. That is, the first reflecting member 81 is disposed in an area on the first end surface 51c side of the light guide 71. The first reflecting member 81 is disposed on the first side wall 33c of the lid 33 and part of the frame 32b of the bottom plate 32. Note that the first reflecting member 81 does not necessarily have to be provided over the entire area described above, but only needs to be provided in at least an area on the first end surface 51c side of the light guide 71.

[0059] The first reflecting member 81 reflects the fluorescence Y and Y1 that have propagated through the light guiding unit 71, the first wavelength conversion element 51, 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, the second excitation light E2, and the fluorescence Y and Y1 that have propagated through the first wavelength conversion element 51, the second wavelength conversion element 52, or the light guiding unit 71 and reached the first reflecting member 81. That is, the first reflecting member 81 reflects the fluorescence Y and Y1, the first excitation light E1, and the second excitation light E2. The first reflecting member 81 is made of, for example, a metal film, a dielectric multilayer film, a scattering member containing barium sulfate, or the like.

[0060] As shown in Figure 3, the third reflecting member 83 is arranged on the third side wall portion 33e of the housing 31 so as to face the first side surface 51e of the first wavelength conversion element 51, the area on the first side surface 51e side of the light-guiding portion 71, and the first side surface 52e of the second wavelength conversion element 52. In addition, the fourth reflecting member 84 is arranged on the fourth side wall portion 33f of the housing 31 so as to face the second side surface 51f of the first wavelength conversion element 51, the area on the second side surface 51f side of the light guiding portion 71, and the second side surface 52f of the second wavelength conversion element 52.

[0061] The third reflecting member 83 reflects the fluorescence Y, Y1, the first excitation light E1, and the second excitation light E2. Therefore, for example, the third reflecting member 83 reflects the first excitation light E1 that has passed through the first wavelength conversion element 51 and the light guiding unit 71 and reached the third reflecting member 83, and causes the first excitation light E1 to enter the first wavelength conversion element 51. This can improve the conversion efficiency of the first excitation light E1 to the fluorescence Y. Furthermore, the third reflecting member 83 reflects the second excitation light E2 that has passed through the second wavelength conversion element 52 and the light guiding unit 71 and reached the third reflecting member 83, and causes the second excitation light E2 to enter the second wavelength conversion element 52. This can improve the conversion efficiency of the second excitation light E2 to the fluorescence Y1.

[0062] Furthermore, the third reflecting member 83 reflects the fluorescence Y that is emitted from the first wavelength conversion element 51, enters the light guiding unit 71, and reaches the third reflecting member 83, and the 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 fluorescence Y. Furthermore, the third reflecting member 83 reflects the fluorescence Y1 that is emitted from the second wavelength conversion element 52, enters the light guiding unit 71, and reaches the third reflecting member 83, and the fluorescence Y1 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 fluorescence Y1.

[0063] Similarly, the fourth reflecting member 84 reflects the fluorescence Y, Y1, 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-described 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.

[0064] 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 illumination light WL emitted from the light source device 30A in each of the light modulation devices 4R, 4G, and 4B, which are the illuminated regions.

[0065] 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, which is perpendicular to the optical axis AX1 of the first lighting device 20. The plurality of first lenses 91a split the illumination light WL 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 4R, 4G, and 4B. 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 4R, 4G, and 4B.

[0066] The illumination light WL 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 4R, 4G, and 4B. 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 first illumination device 20. The superimposing optical system 94 is composed of a single convex lens.

[0067] 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.

[0068] The polarization conversion element 93 converts the polarization direction of the illumination light WL emitted from the second lens array 92. Specifically, the polarization conversion element 93 converts each partial beam of the illumination light WL 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, a reflective layer, and a retardation layer, all of which are not shown. The polarization separation layer transmits one linearly polarized component of the polarization components contained in the illumination light WL 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 reflective layer reflects the other linearly polarized component reflected by the polarization separation layer in a direction parallel to the optical axis AX1. The retardation layer converts the other linearly polarized component reflected by the reflective layer into one linearly polarized component.

[0069] The behavior of light in the light source device 30A of this embodiment will be described below. As shown in FIG. 2, 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 enters the first wavelength conversion element 51. 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 fluorescence Y is emitted in various directions from any light-emitting point.

[0070] The fluorescence Y01 emitted from the first wavelength conversion element 51 is reflected by the first optical layer 61, enters the first light-transmissive member 73, and is emitted to the outside from the end face 73a on the second end face 51d side of the first light-transmissive member 73. Furthermore, the fluorescence Y02 emitted from the first wavelength conversion element 51 passes through the first light-transmissive member 73 and the second wavelength conversion element 52, is reflected by the second optical layer 62, passes through the first light-transmissive member 73 and the first wavelength conversion element 51, is reflected by the first optical layer 61 again, enters the first light-transmissive member 73, and is emitted to the outside from the end face 73a on the second end face 51d side of the first light-transmissive member 73. Although not shown in the figure, a portion of the fluorescence Y that enters the first translucent member 73 is reflected by the back surface 52b of the second wavelength conversion element 52, enters the first translucent member 73 again, and is emitted to the outside from the end face 73a on the second end face 51d side of the first translucent member 73.

[0071] Furthermore, the fluorescence Y03 emitted from the first wavelength conversion element 51 and reaching the first reflecting member 81 is reflected by the first reflecting member 81, then travels toward the +X side, and is reflected, for example, by the first optical layer 61 and the second optical layer 62, thereby propagating inside the first translucent member 73, and is emitted to the outside from the end face 73a of the first translucent member 73.

[0072] In this way, the fluorescence Y emitted from the first wavelength conversion element 51 propagates inside the first light-transmissive member 73 by repeatedly reflecting between the first wavelength conversion element 51 or the first optical layer 61 and the second wavelength conversion element 52 or the second optical layer 62, and is emitted to the outside from the end face 73a on the second end face 51d side of the first light-transmissive member 73. In this embodiment, the end face 73a on the second end face 51d side of the first light-transmissive member 73 corresponds to an example of the "region on the third surface side of the light-guiding section" and the "end face on the third surface side of the first light-transmissive member" of the present invention.

[0073] 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 fluorescence Y1 is emitted from an arbitrary light-emitting point. Note that the behavior of the fluorescence Y1 is the same as that of the fluorescence Y.

[0074] For example, fluorescence Y11 emitted from the second wavelength conversion element 52 is reflected by the second optical layer 62, enters the first light-transmissive member 73, and is emitted to the outside from the end face 73a on the second end face 51d side of the first light-transmissive member 73. Fluorescence Y12 emitted from the second wavelength conversion element 52 directly enters the first light-transmissive member 73 and is emitted to the outside from the end face 73a on the second end face 51d side of the first light-transmissive member 73. Fluorescence Y13 emitted from the second wavelength conversion element 52 and reaches the first reflecting member 81 is reflected by the first reflecting member 81, then travels inside the first light-transmissive member 73 toward the +X side, and is emitted to the outside from the end face 73a of the first light-transmissive member 73.

[0075] In this way, the fluorescence Y1 emitted from the second wavelength conversion element 52 propagates inside the first translucent member 73 by repeatedly reflecting between the first wavelength conversion element 51 or the first optical layer 61 and the second wavelength conversion element 52 or the second optical layer 62, and is emitted to the outside from the end face 73a on the second end face 51d side of the first translucent member 73.

[0076] Therefore, in the light source device 30A of the present embodiment, the fluorescence Y converted by the first wavelength conversion element 51 and the fluorescence Y1 converted by the second wavelength conversion element 52 travel through the light guiding section 71 and are emitted from the end surface 73a of the first light-transmissive member 73. Therefore, according to the light source device 30A of the present embodiment, the illumination light WL containing the fluorescence Y and Y1 can be efficiently extracted to the outside from the extraction port 31K of the housing 31.

[0077] 2 , of the fluorescence Y emitted from the first wavelength conversion element 51, the fluorescence Y0 that is incident on the first optical layer 61 from the normal direction and reflected perpendicularly is unlikely to change its traveling direction while passing through the first wavelength conversion element 51 and the second wavelength conversion element 52, and is repeatedly reflected between the first optical layer 61 and the second optical layer 62. The same is true for the fluorescence Y1 emitted from the second wavelength conversion element 52, where the fluorescence Y1 that is incident on the second optical layer 62 from the normal direction and reflected perpendicularly is repeatedly reflected between the first optical layer 61 and the second optical layer 62. The fluorescence that is repeatedly reflected between the first optical layer 61 and the second optical layer 62 in this way is absorbed and lost while propagating multiple times inside the first wavelength conversion element 51 and the second wavelength conversion element 52.

[0078] In the light source device 30A of this embodiment, illumination light WL is extracted to the outside through the extraction port 31K of the housing 31, so that the etendue of the illumination light WL is small, and loss of the illumination light WL in optical components such as the integrator optical system 90 arranged downstream of the light source device 30A can be reduced. As a result, the utilization efficiency of the illumination light WL in the light source device 30A can be improved.

[0079] 2, in the light source device 30A of this embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are arranged to sandwich the first light-transmissive member 73. Here, as a comparative example, consider a configuration in which a pair of light-transmissive members are arranged to sandwich one wavelength conversion element, and excitation light is made incident from both sides of the wavelength conversion element.

[0080] In the comparative example, the fluorescence generated by the wavelength conversion element is emitted from three locations: the ends of the pair of light-transmitting members and the end of the wavelength conversion element. Here, the amount of fluorescence propagating through the wavelength conversion element and emitted from the end of the wavelength conversion element is less than the amount of fluorescence propagating through each light-transmitting member and emitted from the end of each light-transmitting member. In the comparative example, the illumination light emitted from the pair of translucent members and the wavelength conversion element is dark in the central portion corresponding to the wavelength conversion element and bright in the peripheral portion corresponding to the pair of translucent members, which causes a problem of reduced uniformity in illuminance distribution. Also, in the comparative example, a problem occurs in that a part of the excitation light reflected by the surface of the translucent member returns to the light source side, which causes a loss of excitation light.

[0081] 4, in the case of light source device 30A of the present embodiment, only the end surface 73a of the first light-transmissive member 73 constituting the light-guiding section 71 is exposed from the outlet 31K of the housing 31. For this reason, the illumination light WL emitted by light source device 30A of the present embodiment is made up of fluorescence Y, Y1 that has propagated inside the first light-transmissive member 73, and therefore has more uniform illuminance distribution than the comparative example.

[0082] In Figure 4, the outlet 31K is formed to cover the first wavelength conversion element 51 and the second wavelength conversion element 52, but as will be described later, the first wavelength conversion element 51 and the second wavelength conversion element 52 may be exposed within the outlet 31K depending on the use of the illumination light WL.

[0083] By exposing the first wavelength conversion element 51 and the second wavelength conversion element 52 to the outlet 31K in this manner, the fluorescence Y emitted from the +X-side end face of the first wavelength conversion element 51 and the fluorescence Y1 emitted from the +X-side end face of the second wavelength conversion element 52 can be extracted to the outside through the outlet 31K as part of the illumination light WL, thereby further improving the brightness of the illumination light WL. On the other hand, because the amount of fluorescence Y and Y1 emitted from the end faces of the first wavelength conversion element 51 and the second wavelength conversion element 52 is less than the amount of fluorescence Y and Y1 emitted from the end face of the light guiding section 71, this has a significant impact on the uniformity of the illuminance distribution of the illumination light WL. In contrast, in the light source device 30A of this embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are arranged to sandwich the light guiding section 71, so the illuminance of the peripheral portion of the illumination light WL is lower. This has a smaller impact on the uniformity of the illuminance distribution than the configuration of the comparative example, which significantly reduces the illuminance of the central portion of the illumination light.

[0084] Therefore, in the light source device 30A of this embodiment, if priority is given to the brightness of the illumination light WL, the outlet 31K can be formed so as to expose the first wavelength conversion element 51 and the second wavelength conversion element 52 to the inside, and if priority is given to the illuminance distribution of the illumination light WL, the outlet 31K can be formed so as to cover the first wavelength conversion element 51 and the second wavelength conversion element 52.

[0085] Furthermore, the light source device 30A of this embodiment has a configuration in which no translucent member is disposed between the light source and the wavelength conversion element, so that the excitation light is directly incident on the wavelength conversion element, thereby reducing the occurrence of loss of the excitation light due to reflection on the surface of the translucent member.

[0086] (Effects of the first embodiment) The light source device 30A of this embodiment includes: a first light source 41 that emits excitation light E; a first wavelength conversion element 51 that converts the excitation light E into yellow fluorescence Y; a first optical layer 61 that is arranged between the first light source 41 and the first wavelength conversion element 51 and that transmits the excitation light E and reflects the yellow fluorescence Y; a light guiding section 71 that is arranged on the opposite side of the first wavelength conversion element 51 from the first optical layer 61 and that guides incident light; a second wavelength conversion element 52 that is arranged on the opposite side of the light guiding section 71 from the first wavelength conversion element 51 and that converts the excitation light E that has entered via the first optical layer 61, the first wavelength conversion element 51, and the light guiding section 71 into yellow fluorescence Y1; a second optical layer 62 that is arranged on the opposite side of the second wavelength conversion element 52 from the light guiding section 71 and that reflects the fluorescence Y and the fluorescence Y1; and a first reflecting member 81 that reflects the excitation light E, the fluorescence Y, and the fluorescence Y1. The first wavelength conversion element 51 has a surface 51a on which the excitation light E is incident via the first optical layer 61, and a first end face 51c and a second end face 51d that intersect with the surface 51a and face in opposite directions. A first reflecting member 81 is disposed in a region of the light guiding unit 71 on the side of the first end face 51c. The fluorescence Y converted by the first wavelength conversion element 51 and the fluorescence Y1 converted by the second wavelength conversion element 52 travel through the light guiding unit 71 and are emitted from a region of the light guiding unit 71 on the side of the second end face 51d.

[0087] As described above, according to the light source device 30A of the present embodiment, the fluorescence Y generated by the first wavelength conversion element 51 and the fluorescence Y1 generated by the second wavelength conversion element 52 travel through the light guiding section 71 and are emitted from the end face 73a of the first light-transmissive member 73, which is the area on the second end face 51d side of the light guiding section 71. Therefore, compared to conventional light source devices in which fluorescence is extracted by propagating inside the wavelength conversion element by total reflection, loss of the fluorescence Y and Y1 is reduced, and the utilization efficiency of the fluorescence Y and Y1 can be improved.

[0088] The projector 1 of this embodiment includes a light source device 30A, light modulation devices 4R, 4G, and 4B that modulate the light emitted from the light source device 30A, and a projection optical device 6 that projects the light modulated by the light modulation devices 4R, 4G, and 4B.

[0089] The projector 1 of this embodiment has excellent light utilization efficiency because it is provided with the first illumination device 20 including the light source device 30A that efficiently extracts illumination light WL that includes the fluorescent light Y and Y1.

[0090] (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.

[0091] As shown in FIG. 5, the light source device 30B of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 53, a first optical layer 61, a light guide section 71, a second light source 42, a second wavelength conversion element 54, a second optical layer 62, a first reflecting member 81, a third reflecting member (not shown), and a fourth reflecting member (not shown).

[0092] In the light source device 30A of the first embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are made of transparent phosphors. In contrast, in the light source device 30B of the present embodiment, the first wavelength conversion element 53 and the second wavelength conversion element 54 are made of phosphors with light-scattering properties. A phosphor with light-scattering properties can be realized by dispersing a medium with a refractive index different from that of the transparent phosphor, such as pores or a filler, in the transparent phosphor. The first wavelength conversion element 53 has a front surface 53a and a back surface 53b, a first end surface 53c and a second end surface 53d. The second wavelength conversion element 54 has a front surface 54a and a back surface 54b, a first end surface 54c and a second end surface 54d. The other configurations of the light source device 30B are similar to those of the light source device 30A of the first embodiment.

[0093] (Effects of the second embodiment) In this embodiment, too, the fluorescence Y, Y1 propagates through the light-guiding section 71, thereby achieving the same effects as in the first embodiment, such as reducing the loss of the fluorescence Y, Y1 and realizing a light source device 30B that has excellent utilization efficiency of the fluorescence Y, Y1, and that can efficiently emit the illumination light WL.

[0094] In the first embodiment, since the first wavelength conversion element 51 and the second wavelength conversion element 52 are made of transparent phosphors, the traveling direction of the fluorescence Y emitted from the first wavelength conversion element 51, that of the fluorescence Y0 (see FIG. 2) that is perpendicularly incident on the first optical layer 61, is difficult to change inside the first wavelength conversion element 51 and the second wavelength conversion element 52, and is repeatedly reflected between the first optical layer 61 and the second optical layer 62, resulting in loss. The same applies to the fluorescence Y1 emitted from the second wavelength conversion element 52.

[0095] In contrast to this, in the case of this embodiment, since the first wavelength conversion element 51 and the second wavelength conversion element 54 are made of phosphors having light scattering properties, when the fluorescence Y emitted from the first wavelength conversion element 53 is incident on the second wavelength conversion element 54, a lot of scattering occurs, and the traveling direction of the fluorescence Y changes with each scattering, as shown in Fig. 5. Similarly, since the second wavelength conversion element 54 is made of phosphors having light scattering properties, when the fluorescence Y1 is incident on the second wavelength conversion element 54, a lot of scattering occurs, and the traveling direction of the fluorescence Y1 changes with each scattering.

[0096] For this reason, for example, even fluorescence Y0 that is perpendicularly incident on the second wavelength conversion element 54 is scattered and angle-converted by the second wavelength conversion element 54, and eventually emerges from the end surface 73a of the first light-transmissive member 73. Furthermore, fluorescence that is emitted from the second wavelength conversion element 54 and perpendicularly incident on the first wavelength conversion element 53 is also scattered and angle-converted by the first wavelength conversion element 53, and eventually emerges from the end surface 73a of the first light-transmissive member 73. In this way, the fluorescence Y and Y1 are repeatedly subjected to at least one of scattering by the first wavelength conversion element 53, reflection by the first optical layer 61, scattering by the second wavelength conversion element 54, and reflection by the second optical layer 62, and then emerge from the end surface 73a of the first light-transmissive member 73.

[0097] In the present embodiment, almost no fluorescence Y, Y1 exists that is not emitted to the outside by propagating inside the first wavelength conversion element 53 and the second wavelength conversion element 54. Therefore, according to the light source device 30B of the present embodiment, the fluorescence Y, Y1 can be extracted more efficiently as illumination light WL.

[0098] (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 second embodiment, so a description of the basic configuration of the light source device will be omitted. 6 is a cross-sectional view of a light source device 30C of the third embodiment cut along the XY plane. In Fig. 6, components common to those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0099] 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 53, a first optical layer 61, a second light-transmissive member 63, a light-guiding section 71, a second light source 42, a second wavelength conversion element 54, a second optical layer 62, a third light-transmissive member 64, a first reflecting member 81, a second reflecting member 82, a third reflecting member (not shown), and a fourth reflecting member (not shown).

[0100] In the light source device 30B of the second embodiment, the first optical layer 61 is provided on the surface 53a of the first wavelength conversion element 53, and the second optical layer 62 is provided on the surface 54a of the second wavelength conversion element 54. In contrast, in the light source device 30C of the present embodiment, a second light-transmissive member 63 is arranged between the first optical layer 61 and the first wavelength conversion element 53, and a third light-transmissive member 64 is arranged between the second optical layer 62 and the second wavelength conversion element 54.

[0101] The second light-transmissive member 63 and the third light-transmissive member 64 may be configured of a plate-shaped light-transmissive member similar to the first light-transmissive member 73. Alternatively, the second light-transmissive member 63 and the third light-transmissive member 64 may be formed of a transparent layer having a smooth surface by applying a material such as polysilazane or permeate to each of the wavelength conversion elements 53, 54 and then curing the material.

[0102] The second light-transmissive member 63 has a front surface 63a and a back surface 63b, a first end surface 63c and a second end surface 63d, and a first side surface (not shown) and a second side surface (not shown). The front surface 63a and the back surface 63b intersect the Y axis and face opposite each other along the Y axis. The first end surface 63c and the second end surface 63d intersect the front surface 63a and the back surface 63b and face opposite each other along the X axis direction that is along the longitudinal direction of the second light-transmissive member 63.

[0103] The third light-transmissive member 64 has a front surface 64a and a back surface 64b, a first end surface 64c and a second end surface 64d, and a first side surface (not shown) and a second side surface (not shown). The front surface 64a and the back surface 64b intersect the Y axis and face opposite each other along the Y axis. The first end surface 64c and the second end surface 64d intersect the front surface 64a and the back surface 64b and face opposite each other along the X axis direction that follows the longitudinal direction of the third light-transmissive member 64.

[0104] In the present embodiment as well, the extraction port 31K overlaps with the light guiding unit 71. That is, the extraction port 31K has a shape that covers the first optical layer 61, the first wavelength conversion element 51, the second wavelength conversion element 52, and the second optical layer 62, and exposes the light guiding unit 71 to the inside.

[0105] The second reflecting member 82 reflects the first excitation light E1, the fluorescence Y, the second excitation light E2, and the fluorescence Y1. The second reflecting member 82 is disposed between the housing 31 and the second end face 53d of the first wavelength conversion element 53 and the second end face 63d of the second light-transmissive member 63. The second reflecting member 82 is made of, for example, a metal film or a dielectric multilayer film. The second end face 63d of this embodiment corresponds to an example of the "end face on the third surface side of the second light-transmissive member" of the present invention. The other configurations of the light source device 30C are similar to those of the light source device 30B of the second embodiment.

[0106] (Effects of the third embodiment) In this embodiment, too, the fluorescence Y, Y1 propagates through the light-guiding section 71, thereby achieving the same effects as in the first embodiment, such as reducing the loss of the fluorescence Y, Y1 and realizing a light source device 30C that has excellent utilization efficiency of the fluorescence Y, Y1, and that can efficiently emit the illumination light WL.

[0107] The first wavelength conversion element 53 and the second wavelength conversion element 54, which are made of a phosphor having light scattering properties, have an uneven structure, which reduces the flatness of the surfaces 53a, 54a. Therefore, if the first optical layer 61 and the second optical layer 62 are formed directly on the first wavelength conversion element 53 and the second wavelength conversion element 54, the flatness of the first optical layer 61 and the second optical layer 62 may be reduced, resulting in a risk of degraded optical properties.

[0108] In contrast, in the light source device 30C of this embodiment, the first optical layer 61 and the second optical layer 62 are formed on the second translucent member 63 and the third translucent member 64, so that the first optical layer 61 and the second optical layer 62 can be formed from flat films, thereby improving the optical properties of the first optical layer 61 and the second optical layer 62. Therefore, in the light source device 30C of this embodiment, even when the first wavelength conversion element 53 and the second wavelength conversion element 54 are made of a phosphor having light scattering properties, it is possible to form the first optical layer 61 and the second optical layer 62 having excellent optical properties.

[0109] In the light source device 30C of this embodiment, heat from the first wavelength conversion element 53 is efficiently dissipated via the second light-transmissive member 63, and heat from the second wavelength conversion element 54 is efficiently dissipated via the third light-transmissive member 64. This improves the cooling performance of the first wavelength conversion element 53 and the second wavelength conversion element 54, improves the fluorescence conversion efficiency of the first wavelength conversion element 53 and the second wavelength conversion element 54, and enables the generation of bright fluorescence Y, Y1.

[0110] In the light source device 30C of this embodiment, the fluorescence Y04 or excitation light E11 scattered in the first wavelength conversion element 53 propagates through the second light-transmissive member 63. In contrast, in the light source device 30C of this embodiment, the fluorescence Y04 or excitation light E11 propagating through the second light-transmissive member 63 to the +X side can be reflected by the second reflecting member 82 and made incident on the first wavelength conversion element 53. The excitation light E11 incident on the first wavelength conversion element 53 is used to excite the fluorescence Y, and the fluorescence Y04 incident on the first wavelength conversion element 53 is scattered and emitted into the light-guiding section 71, and then emitted to the outside from the light-guiding section 71. Therefore, in the light source device 30C of this embodiment, the fluorescence Y04 and excitation light E11 propagating through the second light-transmissive member 63 can be extracted from the second light-transmissive member 63 and used efficiently.

[0111] Furthermore, in the light source device 30C of this embodiment, the fluorescence Y14 or excitation light E21 scattered in the second wavelength conversion element 54 propagates through the third light-transmissive member 64. In contrast, in the light source device 30C of this embodiment, the fluorescence Y14 or excitation light E21 propagating through the third light-transmissive member 64 to the +X side can be reflected by the second reflecting member 82 and made incident on the second wavelength conversion element 54. The excitation light E21 incident on the second wavelength conversion element 54 is used to excite the fluorescence Y1, and the fluorescence Y14 incident on the second wavelength conversion element 54 is scattered and emitted into the light-guiding section 71, and then eventually emitted from the light-guiding section 71 to the outside. Therefore, in the light source device 30C of this embodiment, the fluorescence Y14 and excitation light E21 propagating through the third light-transmissive member 64 can be extracted from the third light-transmissive member 64 and used efficiently.

[0112] The configuration of the light source device 30C of this embodiment is also applicable to the light source device 30A of the first embodiment. That is, in the light source device 30A of the first embodiment, a second light-transmissive member 63 may be disposed between the first optical layer 61 and the first wavelength conversion element 51, and a third light-transmissive member 64 may be disposed between the second optical layer 62 and the second wavelength conversion element 52.

[0113] According to this configuration, the heat of the first wavelength conversion element 51 is efficiently dissipated through the second translucent member 63, and the heat of the second wavelength conversion element 52 is efficiently dissipated through the third translucent member 64, thereby improving the fluorescence conversion efficiency of the first wavelength conversion element 51 and the second wavelength conversion element 52 and generating bright fluorescence Y, Y1.

[0114] (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.

[0115] 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 light guide section 76, a second light source 42, a second wavelength conversion element 52, a second optical layer 62, a first reflecting member 81, a third reflecting member (not shown), and a fourth reflecting member (not shown).

[0116] The light guiding section 76 is formed from an air layer 77. That is, the first wavelength conversion element 51 and the second wavelength conversion element 52 are disposed apart from each other, and air exists between the first wavelength conversion element 51 and the second wavelength conversion element 52. The light guiding section 76 guides the fluorescence Y converted by the first wavelength conversion element 51 and the fluorescence Y1 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 section 76 on the first end face 51c side.

[0117] In a plan view taken 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 outlet 31K overlaps with the light guiding unit 76. That is, the extraction outlet 31K has a shape that covers the first optical layer 61, the first wavelength conversion element 51, the second wavelength conversion element 52, and the second optical layer 62, and exposes the light guiding unit 76 to the inside. Therefore, the area of ​​the light guiding unit 76 on the second end face 51d side is exposed to the outside through the extraction outlet 31K. The other configurations of the light source device 30D are similar to those of the light source device 30A of the first embodiment.

[0118] The behavior of light in the light source device 30D of this embodiment will be described below. As shown in FIG. 7, in the light source device 30D, 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 is incident on the first wavelength conversion element 51, the phosphor contained inside the first wavelength conversion element 51 is excited, and fluorescence Y is emitted in various directions from any light-emitting point.

[0119] Fluorescence Y05 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 the area on the second end surface 51d side of the air layer 77.

[0120] In addition, the fluorescence Y that is incident on the back surface 51b of the first wavelength conversion element 51 at an incident angle equal to or greater than the critical angle does not change its direction of travel when passing through the first wavelength conversion element 51 made of a transparent phosphor, and therefore is absorbed by the phosphor and lost as it propagates inside the first wavelength conversion element 51, repeatedly being totally reflected at the back surface 51b of the first wavelength conversion element 51 and reflected at the first optical layer 61 and the first reflecting member 81.

[0121] The fluorescence Y06 is emitted from the first wavelength conversion element 51, travels through the air layer 77 toward the +X side, and enters the second wavelength conversion element 52. After traveling through the air layer 77 while being repeatedly reflected by the second optical layer 62 and the first optical layer 61, the fluorescence Y06 is emitted to the outside from the area on the second end face 51d side of the air layer 77. The fluorescence Y07 is emitted from the first wavelength conversion element 51, travels through the air layer 77 toward the -X side, and enters the second wavelength conversion element 52. The fluorescence Y07 travels through the air layer 77 while being repeatedly reflected by the second optical layer 62 and the first optical layer 61, and then is reflected by the first reflecting member 81. The fluorescence Y07 then travels through the air layer 77 while being repeatedly reflected by the second optical layer 62 and the first optical layer 61 again, and then is emitted to the outside from the area on the second end face 51d side of the air layer 77.

[0122] 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 fluorescence Y1 is emitted from an arbitrary light-emitting point.

[0123] Fluorescence Y15 incident on the rear 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 the area on the second end surface 51d side of the air layer 77.

[0124] In addition, the fluorescence Y15 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 does not change its direction of travel when passing through the second wavelength conversion element 52 made of a transparent phosphor, and therefore is absorbed by the phosphor and lost while propagating inside the second wavelength conversion element 52, repeatedly being totally reflected at the back surface 52b of the second wavelength conversion element 52 and reflected at the second optical layer 62 and the first reflecting member 81.

[0125] The fluorescence Y16 emitted from the second wavelength conversion element 52 travels through the air layer 77 toward the +X side and enters the first wavelength conversion element 51. After traveling through the air layer 77 while being repeatedly reflected by the first optical layer 61 and the second optical layer 62, the fluorescence Y16 is emitted to the outside from a region of the air layer 77 on the second end face 51d side. The fluorescence Y17 emitted from the second wavelength conversion element 52 travels through the air layer 77 toward the -X side and enters the first wavelength conversion element 51. The fluorescence Y17 is reflected by the first reflecting member 81 and is emitted to the outside from a region of the air layer 77 on the second end face 51d side. Note that after being reflected by the first reflecting member 81, the fluorescence Y17 may travel through the air layer 77 while being repeatedly reflected by the second optical layer 62 and the first optical layer 61, and then be emitted to the outside from a region of the air layer 77 on the second end face 51d side.

[0126] As described above, the 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. The fluorescence Y1 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. That is, the fluorescence Y converted by the first wavelength conversion element 51 and the fluorescence Y1 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 30D can emit yellow illumination light WL containing the fluorescence Y converted by the first wavelength conversion element 51 and the fluorescence Y1 converted by the second wavelength conversion element 52 to the outside from the outlet 31K of the housing 31.

[0127] (Effects of the fourth embodiment) In this embodiment, too, the fluorescence Y, Y1 propagates through the light-guiding section 76, thereby achieving the same effects as in the first embodiment, such as reducing the loss of the fluorescence Y, Y1 and realizing a light source device 30D that has excellent utilization efficiency of the fluorescence Y, Y1, and that can efficiently emit the illumination light WL.

[0128] In the present embodiment, the light guide section 76 that guides the fluorescent light Y and Y1 is configured with the air layer 77, and therefore the following effects can be obtained. When an air layer 77 is provided adjacent to the first wavelength conversion element 51 and the second wavelength conversion element 52 as the light-guiding section 76, as in the present embodiment, the refractive index of YAG constituting the wavelength conversion elements is approximately 1.7, and the refractive index of air is approximately 1.0. Therefore, the refractive index difference between each wavelength conversion element 51, 52 and the air layer 77 is approximately 0.7. On the other hand, if the first light-transmissive member 73 is made of quartz (refractive index 1.4), for example, the refractive index difference between the wavelength conversion elements 51, 52 and the light-guiding section 71 in the first embodiment is approximately 0.3. Therefore, the refractive index difference in this embodiment is larger than the refractive index difference in the first embodiment. Therefore, the fluorescence Y, Y1 emitted from each wavelength conversion element 51, 52 and incident on the air layer 77 travels in a direction that forms a smaller angle with respect to the optical axis AX1 than when incident on the first light-transmissive member 73. Therefore, the fluorescence Y, Y1 emitted into the air layer 77 travels along the optical axis AX1, making it easier to extract it from the extraction port 31K.

[0129] Furthermore, in the case of the present embodiment, the air layer 77 is open to the external space at the outlet 31K and has no refractive index interface, so the fluorescence Y, Y1 that reaches the outlet 31K is emitted directly into the external space without being reflected or refracted. Due to the above-described action, the light source device 30D of the present embodiment can improve the extraction efficiency of the fluorescence Y, Y1 compared to the first embodiment.

[0130] 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.

[0131] (Fifth embodiment) Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG. The basic configuration of the light source device of the fifth embodiment is the same as that of the second embodiment, and therefore a description of the basic configuration of the light source device will be omitted. Fig. 8 is a cross-sectional view of a light source device 30E of the fifth embodiment cut along the XY plane. In Fig. 8, components common to those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0132] As shown in Figure 8, the light source device 30E of this embodiment includes a housing 31, a first light source 41, a first wavelength conversion element 53, a first optical layer 61, a light-guiding section 76 consisting of an air layer 77, a second light source 42, a second wavelength conversion element 54, the second optical layer 62, a first reflecting member 81, a third reflecting member (not shown), and a fourth reflecting member (not shown). The other configurations of the light source device 30E are similar to those of the light source device 30B of the second embodiment.

[0133] (Effects of the fifth embodiment) In this embodiment, too, the first wavelength conversion element 53 and the second wavelength conversion element 54 are made of scattering phosphor, and therefore, the same effects as in the second embodiment can be obtained, such as realizing a light source device 30E with little loss of fluorescence Y, Y1 and excellent utilization efficiency of fluorescence Y, Y1, and realizing a light source device 30E that can efficiently emit illumination light WL.

[0134] Furthermore, in the present embodiment, the fluorescence Y, Y1 is emitted from each wavelength conversion element 51, 52 toward the light-guiding section 76 consisting of the air layer 77 in a direction that forms a small angle with respect to the optical axis AX1, and therefore the extraction efficiency of the fluorescence Y, Y1 can be improved compared to the second embodiment.

[0135] (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 third embodiment, and therefore a description of the basic configuration of the light source device will be omitted. 9 is a cross-sectional view of a light source device 30F of the sixth embodiment cut along the XY plane. In Fig. 9, components common to those in the third embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0136] As shown in Figure 9, the light source device 30F 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-transmissive member 63, a light-guiding section 76, a second light source 42, a second wavelength conversion element 54, a second optical layer 62, a third light-transmissive member 64, a first reflecting member 81, a second reflecting member 82, a third reflecting member (not shown), and a fourth reflecting member (not shown). The other configurations of the light source device 30F are similar to those of the light source device 30C of the third embodiment.

[0137] (Effects of the sixth embodiment) In this embodiment, by providing the second light-transmitting member 63, the third light-transmitting member 64, and the second reflecting member 82, it is possible to achieve the same effects as in the third embodiment, such as realizing a light source device 30F that has little loss of the fluorescence Y, Y1 and is excellent in utilization efficiency of the fluorescence Y, Y1 and excitation light, and that can efficiently emit the illumination light WL.

[0138] Furthermore, in the present embodiment, the fluorescence Y, Y1 is emitted from each wavelength conversion element 51, 52 toward the light-guiding section 76 consisting of the air layer 77 in a direction that forms a small angle with respect to the optical axis AX1, and therefore the extraction efficiency of the fluorescence Y, Y1 can be improved compared to the third embodiment.

[0139] 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, in the above-described embodiment, a composite phosphor containing, for example, 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 secured, 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.

[0140] Although the light source devices of the above embodiments are all provided with the second light source, they may be configured to include only the first light source. In this case, the second wavelength conversion element converts the first excitation light emitted from the first light source and transmitted through the first optical layer, the first wavelength conversion element, and the light guiding section into yellow fluorescence.

[0141] 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.

[0142] 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.

[0143] Summary of this disclosure A summary of this disclosure is provided below.

[0144] (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 light guide portion disposed on the opposite side of the first optical layer with respect to the first wavelength conversion element, and configured to guide the second light converted by the first wavelength conversion element; a second wavelength conversion element that is disposed on the opposite side of the light guiding section from the first wavelength conversion element and that converts the first light incident via the first wavelength conversion element and the light guiding section into third light having a third wavelength different from the first wavelength; a second optical layer that is disposed on the opposite side of the second wavelength conversion element from the light guiding unit and that reflects the second light and the third light; a first reflecting member that reflects the first light, the second light, and the third 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 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 third 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. Light source device.

[0145] According to the light source device having this configuration, the second light and the third light propagate through the light guide, so that the loss of the second light and the third light is small and the light source device has excellent utilization efficiency of the second light and the third light. Also, a light source device capable of efficiently emitting illumination light including the second light and the third light can be realized.

[0146] (Appendix 2) further comprising a housing that accommodates 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 third light emitted from the region on the third surface side of the light guiding section are extracted to the outside, In a planar view in a normal direction of the third surface of the first wavelength conversion element, the extraction port overlaps with the light guiding portion. 10. The light source device of claim 1.

[0147] According to this configuration, the first optical layer, the second optical layer, the first wavelength conversion element, and the second wavelength conversion element can be protected by the housing, and the second light and the third light propagating inside the light guiding section can be extracted to the outside through the extraction port of the housing as illumination light. The extraction port prevents the second light and the third light, which have relatively low illuminance and are emitted from the end face on the third surface side of the first wavelength conversion element, from being extracted to the outside, and therefore, the uniformity of the illuminance distribution of the illumination light emitted from the extraction port can be improved.

[0148] (Appendix 3) a first light-transmitting member that transmits the first light, the second light, and the third light is disposed in the light guide portion; the second light converted by the first wavelength conversion element and the third light converted by the second wavelength conversion element travel inside the second light-transmitting member and are emitted from an end face of the first light-transmitting member on the third surface side. 10. The light source device according to claim 1 or 2.

[0149] According to this configuration, since the first light-transmissive member is disposed in the light guiding section, the refractive index difference 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 third light generated by each wavelength conversion element into the light guiding section and reduces loss due to re-absorption of the second light and the third light.

[0150] (Appendix 4) further comprising a second light-transmitting member disposed between the first wavelength conversion element and the first optical layer; 4. A light source device according to any one of claims 1 to 3.

[0151] According to this configuration, by forming the first optical layer on the flat second light-transmissive member, the first optical layer can be formed as a flat film compared to when the first optical layer is formed on the surface of the first wavelength conversion element, and therefore the optical properties of the first optical layer can be easily improved. Also, heat generated in the first wavelength conversion element can be dissipated through the second light-transmissive member. Therefore, the cooling performance of the first wavelength conversion element can be improved.

[0152] (Appendix 5) a housing that accommodates the first optical layer, the second optical layer, the first wavelength conversion element, the second wavelength conversion element, and the second light-transmitting member; a second reflecting member that reflects the first light, the second light, and the third light; Furthermore, the housing has an outlet through which the second light and the third light emitted from the region on the third surface side of the light guiding section are extracted to the outside, the extraction port overlaps the light guiding portion in a planar view in a normal direction of the third surface of the first wavelength conversion element, the second reflecting member is disposed between the housing and the third surface of the first wavelength conversion element and an end surface of the second light-transmitting member on the third surface side. 5. The light source device according to claim 4.

[0153] According to this configuration, the housing can protect the first optical layer, the second optical layer, the first wavelength conversion element, the second wavelength conversion element, and the second translucent member, and the second light and the third light propagating inside the light-guiding section can be extracted to the outside through the extraction port of the housing as illumination light. Furthermore, the first light or the second light that has been scattered in the first wavelength conversion element and propagated through the second light-transmissive member can be reflected by the second reflecting member and made incident on the first wavelength conversion element. The first light that has entered the first wavelength conversion element is used to excite the second light, and the second light that has entered the first wavelength conversion element is scattered and emitted to the outside from the light-guiding section. Therefore, the first light or the second light that has propagated through the second light-transmissive member can be efficiently extracted and used from the second light-transmissive member.

[0154] (Appendix 6) the light guide portion is an air layer, the second light converted by the first wavelength conversion element and the third 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. 10. The light source device according to claim 1 or 2.

[0155] With this configuration, the refractive index difference between each wavelength conversion element and the light guide is greater than in a configuration in which the second light and the third light enter a translucent member, so the second light and the third light travel in a direction that forms a small angle with respect to the longitudinal direction of each wavelength conversion element. Furthermore, since the air layer on the third surface side is open to the outside and does not have a refractive index interface, the second light and the third light that reach the region on the third surface side are emitted directly into the external space without reflection or refraction. This increases the extraction efficiency of the second light and the third light.

[0156] (Appendix 7) further comprising a third reflecting member and a fourth reflecting member that reflect the first light, the second light, and the third light, the first wavelength conversion element has a fourth surface and a fifth surface that intersect with the first surface, the second surface, and the third surface and face in opposite directions to each other; the third reflecting member is disposed in an area on the fourth surface side of the light guiding unit, The fourth reflecting member is disposed in an area on the fifth surface side of the light guiding section. 7. A light source device according to any one of claims 1 to 6.

[0157] With this configuration, the third and fourth reflecting members can increase the efficiency of converting the first light into the second light and the first light into the third light, and can also reduce the loss of each light beam emitted from the fourth and fifth surfaces and absorbed by the housing.

[0158] (Appendix 8) The first wavelength conversion element and the second wavelength conversion element are made of a transparent phosphor. 8. A light source device according to any one of claims 1 to 7.

[0159] According to this configuration, even when the first wavelength conversion element and the second wavelength conversion element made of transparent phosphor are used, the second light and the third light can be efficiently extracted to the outside from the third surface side of the light guide section.

[0160] (Appendix 9) The first wavelength conversion element and the second wavelength conversion element are made of a phosphor having light scattering properties. 9. A light source device according to any one of claims 1 to 8.

[0161] With this configuration, the propagation directions of the second light and the third light are changed in various directions due to the scattering of light by the wavelength conversion element, and the second light and the third light can be efficiently emitted from the third surface after propagating inside the light guiding section, thereby reducing loss of the second light and the third light and further increasing the extraction efficiency of the second light and the third light.

[0162] (Appendix 10) the first wavelength conversion element and the second wavelength conversion element contain a yellow phosphor; the first light and the third light are blue light, the second light and the fourth light are yellow fluorescent light, the fluorescence propagates through the light guiding unit while repeating at least one of scattering by the first wavelength conversion element, reflection by the first optical layer, scattering by the second wavelength conversion element, and reflection by the second optical layer, and is emitted from a region on the third surface side of the light guiding unit. 10. The light source device according to claim 9.

[0163] According to this configuration, the yellow fluorescence generated by the first wavelength conversion element and the second wavelength conversion element can be efficiently extracted from the third surface side of the light guide section.

[0164] (Appendix 11) a second light source that is disposed on the opposite side of the second wavelength conversion element from the light guiding unit and that emits the first light; the second wavelength conversion element converts the first light emitted from the second light source, transmitted through the second optical layer, and incident thereon into the third light. 11. A light source device according to any one of claims 1 to 10.

[0165] According to this configuration, the first light emitted from the second light source can be incident on the second wavelength conversion element, thereby increasing the amount of third light emitted from the second wavelength conversion element.

[0166] (Appendix 12) A light source device according to any one of Supplementary Note 1 to Supplementary Note 11; a light modulation device that modulates the light emitted from the light source device; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

[0167] According to a projector having this configuration, since it is equipped with a light source device that extracts light efficiently, it is possible to provide a projector with excellent light utilization efficiency. [Explanation of symbols]

[0168] 1...Projector, 4B, 4G, 4R...Light modulation device, 6...Projection optical device, 30A, 30B, 30C, 30D, 30E, 30F...Light source device, 31...Housing, 31K...Outlet, 41...First light source, 42...Second light source, 51a...Surface (first surface), 51c...First end surface (second surface), 51d...Second end surface (third surface), 51e...First side surface (fourth surface), 51f...Second side surface (fifth surface), 51, 53...First wavelength conversion element, 52, 54...Second wavelength conversion element, 61...First optical layer, 62...Second Optical layer, 63d...second end face (end face on the third surface side of the second light-transmissive member), 63...second light-transmissive member, 71, 76...light-guiding section, 73...first light-transmissive member, 73a...end face (region on the third surface side of the light-guiding section, end face on the third surface side of the first light-transmissive member), 77...air layer, 81...first reflecting member, 82...second reflecting member, 83...third reflecting member, 84...fourth reflecting member, E1...first excitation light (first light in first wavelength band), E2...second excitation light (first light in first wavelength band), Y...fluorescence (second light), Y1...fluorescence (third 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 light guide portion that is disposed on an opposite side of the first optical layer with respect to the first wavelength conversion element and guides incident light; a second wavelength conversion element that is disposed on an opposite side of the light guiding section from the first wavelength conversion element, and that converts the first light incident via the first optical layer, the first wavelength conversion element, and the light guiding section into third light of a third wavelength band different from the first wavelength band; a second optical layer disposed on the opposite side of the second wavelength conversion element from the light guiding unit and reflecting the second light and the third light; a first reflecting member that reflects the first light, the second light, and the third 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 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 third light converted by the second wavelength conversion element travel through the light guiding portion and are emitted from a region on the third surface side of the light guiding portion. Light source device.

2. further comprising a housing that accommodates 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 third light emitted from the region on the third surface side of the light guiding section are extracted to the outside, In a planar view in a normal direction of the third surface of the first wavelength conversion element, the extraction port overlaps with the light guiding portion. The light source device according to claim 1 .

3. a first light-transmitting member that transmits the first light, the second light, and the third light is disposed in the light guide portion; the second light converted by the first wavelength conversion element and the third light converted by the second wavelength conversion element travel inside the first light-transmitting member and are emitted from an end face of the first light-transmitting member on the third surface side. The light source device according to claim 1 .

4. Further provided is a second light-transmitting member disposed between the first wavelength conversion element and the first optical layer. The light source device according to claim 1 .

5. a housing that accommodates the first optical layer, the second optical layer, the first wavelength conversion element, the second wavelength conversion element, and the second light-transmitting member; a second reflecting member that reflects the first light, the second light, and the third light; Furthermore, the housing has an outlet through which the second light and the third light emitted from the region on the third surface side of the light guiding section are extracted to the outside, In a planar view in a normal direction of the third surface of the first wavelength conversion element, the extraction port overlaps the light guiding portion, the second reflecting member is disposed between the housing and an end face of the first wavelength conversion element on the third surface side and an end face of the second light-transmitting member on the third surface side. The light source device according to claim 4 .

6. the light guide portion is an air layer, the second light converted by the first wavelength conversion element and the third 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. The light source device according to claim 1 .

7. a third reflecting member and a fourth reflecting member that reflect the first light, the second light, and the third light, respectively; the first wavelength conversion element has a fourth surface and a fifth surface that intersect with the first surface, the second surface, and the third surface and face in opposite directions to each other; the third reflecting member is disposed in an area on a fourth surface side of the light guiding section, The fourth reflecting member is disposed in an area on the fifth surface side of the light guiding section. The light source device according to claim 1 .

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

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

10. the first wavelength conversion element and the second wavelength conversion element contain a yellow phosphor; the first light is blue light, the second light and the third light are yellow fluorescent light, the fluorescence propagates through the light guiding unit while repeating at least one of scattering by the first wavelength conversion element, reflection by the first optical layer, scattering by the second wavelength conversion element, and reflection by the second optical layer, and is emitted from a region on the third surface side of the light guiding unit. The light source device according to claim 9 .

11. a second light source that is disposed on the opposite side of the second wavelength conversion element from the light guiding unit and that emits the first light; the second wavelength conversion element converts the first light emitted from the second light source, transmitted through the second optical layer, and incident thereon into the third light. The light source device according to claim 1 .

12. The light source device according to any one of claims 1 to 6, 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, projector.

Images