Light source device and projector

Abstract

To provide a light source device and a projector excellent in light utilization efficiency.SOLUTION: The light source apparatus according to the present disclosure includes the first light source that outputs the first light, the first wavelength converter that converts the first light into the second light, the first optical layer that transmits the first light and reflects the second light, the second light source that outputs the third light, and the light guide that guides the second light and the third light. The first wavelength converter has a first surface on which the first light is incident via the first optical layer, and a second surface and a third surface that intersect the first surface and face away from each other. The second light source is arranged in a region on the second surface side of the light guide part. The first optical layer reflects the third light in addition to the second light, and a part of the second light and the third light travels through the light guide portion and is emitted from a region on the third surface side of the light guide portion.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-mentioned problems, a light source device according to one aspect of the present invention includes a first light source that emits first light in a first wavelength band, a 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 second light source that emits third light in a third wavelength band different from the second wavelength band, and a second optical layer that is disposed between the first wavelength conversion element and the first optical layer and that transmits the second light converted by the first wavelength conversion element and the second light emitted from the second light source. and a light guiding section that guides the third light, wherein the first wavelength conversion element has a first surface into which the first light is incident via the first optical layer, and a second surface and a third surface that intersect the first surface and face in opposite directions, the second light source is arranged in an area on the second surface side of the light guiding section, the first optical layer reflects the third light emitted from the second light source in addition to the second light, and some of the second light converted by the first wavelength conversion element and the third light emitted from the second light source travel through the light guiding section and are emitted from the area on the third surface side of the light guiding section.

[0006] Further, a light source device according to another 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 arranged 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 that is arranged on the opposite side of the first wavelength conversion element to the first optical layer and that guides incident light; a second wavelength conversion element that is arranged on the opposite side of the light guide element to the first wavelength conversion element and that converts the first light that has entered through the first optical layer, the first wavelength conversion element, and the light guide into third light in a third wavelength band different from the first wavelength band; and a second optical layer that reflects the fourth light of a fourth wavelength band different from the second wavelength band and the third wavelength band, the first wavelength conversion element having a first surface to which the first light is incident via the first optical layer, and a second surface and a third surface that intersect with the first surface and face in opposite directions, the second light source being disposed in a region on the second surface side of the light guiding unit, the first optical layer and the second optical layer reflect the fourth light emitted from the second light source in addition to the second light and the third light, and some of the second light converted by the first wavelength conversion element, the third light converted by the second wavelength conversion element, and the fourth light emitted from the second light source travel through the light guiding unit and are emitted from the region on the third surface side of the light guiding unit.

[0007] A projector according to one aspect of the present invention comprises a light source device according to one aspect of the present invention, an optical modulation device that modulates light emitted from the light source device, and a projection optical device that projects the light modulated by the optical modulation device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic configuration diagram of a projector according to a first embodiment. [Figure 2] FIG. 1 is a perspective view of a light source device according to a first embodiment. [Figure 3] 3 is a cross-sectional view of the light source device taken along line III-III in FIG. 2. FIG. [Figure 4] 1 is a plan view of the light source device of the first embodiment 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] 8 is a cross-sectional view of the light source device taken along line VIII-VIII in FIG. 7. [Figure 9] FIG. 10 is a plan view of the light source device of the fourth embodiment as viewed from the +X side to the −X side. [Figure 10] 10A and 10B are schematic diagrams for explaining the operation of the light source device of the fifth embodiment. [Figure 11] FIG. 10 is a cross-sectional view of a light source device according to a sixth embodiment. [Figure 12] FIG. 13 is a cross-sectional view of a light source device according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) A first embodiment of the present invention will be described below with reference to the drawings. The projector of this embodiment is an example of a projector that uses a liquid crystal panel as a light modulation device. In the drawings below, the dimensions of some components may be shown on different scales to make them easier to see.

[0010] FIG. 1 is a schematic configuration diagram of a projector 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.

[0011] The projector 1 includes an illumination device 20, 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.

[0012] The illumination device 20 includes a light source device 30A, an integrator optical system 90, a polarization conversion element 93, and a superimposing optical system 94. The illumination device 20 emits white illumination light WL containing red light LR, green light LG, and blue light LB. The specific configuration of the illumination device 20 will be described later.

[0013] In the following, in the drawings, an XYZ Cartesian coordinate system will be used as necessary for explanation. The X axis is an axis parallel to the optical axis AX1 of the lighting device 20 and is an axis along the front-to-rear direction of the projector 1. The Y axis is an axis perpendicular to the X axis and is an axis along the up-and-down direction of the projector 1. The Z axis is an axis perpendicular to the X axis and Y axis and is an axis along the left-to-right direction of the projector 1. These notations are used to explain the positional relationship of the components of the projector 1 and do not limit the installation posture or direction of the projector 1. The optical axis AX1 of the lighting device 20 is the central axis of the illumination light WL emitted from the lighting device 20.

[0014] One of the two directions along the X axis is called the +X direction, and the opposite direction is called the -X direction; one of the two directions along the Y axis is called the +Y direction, and the opposite direction is called the -Y direction; and one of the two directions along the Z axis is called the +Z direction, and the opposite direction is called 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.

[0015] The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first reflecting mirror 8a, a second reflecting mirror 8b, a third reflecting mirror 8c, a first relay lens 15, and a second relay lens 16. The color separation optical system 3 separates the illumination light WL emitted from the illumination device 20 into red light LR, green light LG, and blue light LB, and guides the red light LR to the red light optical modulation device 4R, the green light LG to the green light optical modulation device 4G, and the blue light LB to the blue light optical modulation device 4B.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] Next, the light source device 30A, which is a main component of the illumination device 20, will be described. 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.

[0022] As shown in Figures 2 and 3, the light source device 30A of this embodiment includes a housing 31, a pair of first light sources 41, a first wavelength conversion element 51, a pair of first optical layers 61, a pair of second optical layers 62, a third optical layer 63, a pair of light-guiding sections 71, a second light source 42, a first reflecting member 81, and a second reflecting member 82.

[0023] The housing 31 constitutes the exterior of the light source device 30A. The housing 31 accommodates the first light source 41, the first optical layer 61, the second optical layer 62, the third optical layer 63, the light guiding section 71, the first wavelength conversion element 51, the second light source 42, the first reflecting member 81, and the second reflecting member 82. The housing 31 is composed of a bottom plate section 32 and a lid body 33. The lid body 33 has a box-like shape with one side open, and has a top wall section 33a, a first side wall section 33c, a second side wall section 33d, a third side wall section 33e, a fourth side wall section 33f, and an opening 33K.

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

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

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

[0027] The 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 guiding unit 71 via the first reflecting member 81 and the second reflecting member 82 in a heat-transferable manner. For this reason, like the bottom plate 32, the lid 33 is desirably made of a material that has a predetermined strength and high thermal conductivity. For this reason, like the bottom plate, the lid 33 is desirably made of a metal such as aluminum or stainless steel, and in particular, an aluminum alloy such as 6061 series is desirably used.

[0028] According to this configuration, heat from the first wavelength conversion element 51 and the light guiding section 71 is released to the outside through the lid 33, thereby suppressing a temperature rise in the first wavelength conversion element 51 and the light guiding section 71. As a result, a decrease in wavelength conversion efficiency due to a temperature rise in the first wavelength conversion element 51 can be suppressed.

[0029] 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 second optical layer 62, the third optical layer 63, the light guide 71, the first wavelength conversion element 51, the second light source 42, the first reflecting member 81, and the second reflecting member 82 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.

[0030] The housing 31 has an outlet 31K for extracting to the outside the light emitted from the light guiding unit 71 and the first wavelength conversion element 51. The outlet 31K is an opening defined by an opening 33K provided in the second side wall portion 33d of the lid body 33 and a part of the frame portion 32b of the bottom plate portion 32. According to this configuration, the housing 31 can protect the first light source 41, the first optical layer 61, the second optical layer 62, the third optical layer 63, the light guiding unit 71, the first wavelength conversion element 51, the second light source 42, the first reflecting member 81, and the second reflecting member 82, and can extract to the outside the light propagating inside the light guiding unit 71 through the outlet 31K as illumination light WL.

[0031] 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 outlet 31K overlaps the light guiding unit 71 and the first wavelength conversion element 51. In this embodiment, the extraction outlet 31K has a shape that exposes the first wavelength conversion element 51, the pair of light guiding units 71, and the pair of second optical layers 62 to the inside, but does not expose the pair of first optical layers 61 to the inside. The extraction outlet 31K may also have a shape that exposes the pair of first optical layers 61 to the inside.

[0032] The light source device 30A of this embodiment can efficiently extract white light containing fluorescence Y and blue light B propagated inside the light-guiding section 71 and fluorescence Y emitted from the first wavelength conversion element 51 as illumination light WL through the extraction outlet 31K of the housing 31. 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.

[0033] As shown in FIG. 2, each of the pair of first light sources 41 has a plurality of first light-emitting elements 411. The plurality of first light-emitting elements 411 constituting one first light source 41 are mounted on the top wall portion 33a of the housing 31, and the plurality of first light-emitting elements 411 constituting the other first light source 41 are mounted on the base portion 32a of the housing 31. The number of first light-emitting elements 411 included in the first light source is not particularly limited. The first light-emitting element 411 emits excitation light in a first wavelength band. The first light-emitting element 411 is formed, for example, of a light-emitting diode (LED). The first light-emitting element 411 is disposed opposite the first wavelength conversion element 51 and emits excitation light toward the first wavelength conversion element 51. The first wavelength band is an ultraviolet wavelength band, and the center wavelength is, for example, 380 nm. The plurality of first light-emitting elements 411 are disposed 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 excitation light E of the first wavelength band consisting of a plurality of excitation light rays toward the first wavelength conversion element 51. The excitation light E of this embodiment corresponds to an example of the "first light of the first wavelength band" of the present invention.

[0034] The second light source 42 has one second light-emitting element 421. The second light-emitting element 421 is mounted on the first side wall 33c of the housing 31. The number of second light-emitting elements 421 is not particularly limited. The second light-emitting element 421 emits blue light in a third wavelength band different from the second wavelength band. The second light-emitting element 421 is configured, for example, by an LED. The second light-emitting element 421 is disposed opposite the first end surface 51c of the first wavelength conversion element 51 and the end surface 73b of the light-guiding unit 71 (first translucent member 73) on the first end surface 51c side, and emits blue light B toward the first wavelength conversion element 51 and the first translucent member 73. The third wavelength band is a blue wavelength band, and has a center wavelength of, for example, 550 nm. The blue light B in this embodiment corresponds to the "third light in the third wavelength band" of the present invention. In this embodiment, the second wavelength band of the blue light B is wider than the first wavelength band of the excitation light E.

[0035] 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.

[0036] The first wavelength conversion element 51 has a front surface 51a, a back surface 51b, a first end surface 51c, a second end surface 51d, a first side surface 51e, and a second side surface 51f. The front surface 51a and the back surface 51b intersect with the Y axis and face opposite sides along the Y axis. In this embodiment, the front surface 51a is located on the +Y side, which is one side along the Y axis. The back surface 51b is located on the -Y side, which is the other side along the Y axis. Excitation light E is incident on the front surface 51a from the first light source 41 arranged on the top wall 33a via the first optical layer 61 and the light guide 71. Furthermore, excitation light E is incident on the back surface 51b from the first light source 41 arranged on the base 32a via the first optical layer 61 and the light guide 71. The front surface 51a and the back surface 51b in this embodiment correspond to an example of a "first surface" in the present invention.

[0037] 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.

[0038] 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.

[0039] The first wavelength conversion element 51 contains at least a yellow phosphor and converts the excitation light E of the 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.

[0040] The first wavelength conversion element 51 includes a ceramic phosphor made of a polycrystalline phosphor that converts the wavelength of the excitation light E 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, i.e., 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. In other words, in this embodiment, the second wavelength band of the fluorescence Y is wider than the third wavelength band of the blue light B.

[0041] 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 excitation light E into yellow fluorescence Y.

[0042] The first optical layer 61 is disposed between the first light source 41 and the first wavelength conversion element 51. Specifically, the first optical layer 61 is disposed between the first light source 41 and the first wavelength conversion element 51 on the bottom plate 32 side, and between the first light source 41 and the first wavelength conversion element 51 on the top wall 33a side. The first optical layer 61 has optical properties of transmitting the excitation light E and reflecting the yellow fluorescence Y. The first optical layer 61 reflects the blue light B emitted from the second light source 42 in addition to the fluorescence Y. The first optical layer 61 is formed of, for example, a dielectric multilayer film. The first optical layer 61 is disposed on a surface of the light guide 71 (described later) facing the first light source 41.

[0043] The light guiding unit 71 is disposed between the first optical layer 61 and the first wavelength conversion element 51. Specifically, the light guiding unit 71 is disposed between the first optical layer 61 and the first wavelength conversion element 51 on the side closer to the bottom plate 32, and between the first optical layer 61 and the first wavelength conversion element 51 on the side closer to the top wall 33a. The light guiding unit 71 guides the yellow fluorescence Y converted by the first wavelength conversion element 51 and part of the blue light B emitted from the second light source 42. In this embodiment, a first light-transmissive member 73 that transmits the excitation light E and the yellow fluorescence Y is disposed in the light guiding unit 71. The first light-transmissive member 73 is bonded to the front surface 51a and the back surface 51b of the first wavelength conversion element 51 with an optical adhesive.

[0044] The first light-transmissive member 73 is made of a light-transmissive material that allows the excitation light E, the fluorescence Y, and the blue light B to pass through, such as borosilicate glass such as BK7, quartz, synthetic quartz, crystal, SiC, GaN, MgO, YAG, sapphire, or diamond. 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 long in the X-axis direction.

[0045] The thermal conductivity of the first light-transmissive member 73 is desirably greater than the thermal conductivity of the first wavelength conversion element 51. Materials for the first light-transmissive member 73 that satisfy this relationship include, for example, SiC, GaN, MgO, YAG, sapphire, and diamond. With this configuration, heat from the first wavelength conversion element 51 is efficiently conducted to the first light-transmissive member 73, thereby suppressing a temperature rise in the first wavelength conversion element 51. This makes it possible to suppress a decrease in conversion efficiency due to a temperature rise in the first wavelength conversion element 51.

[0046] The second optical layer 62 is disposed between the first wavelength conversion element 51 and the light guiding section 71. Specifically, the second optical layer 62 is disposed between the light guiding section 71 on the bottom plate section 32 side and the first wavelength conversion element 51, and between the light guiding section 71 on the top wall section 33a side and the first wavelength conversion element 51. In the present embodiment, the second optical layer 62 is provided so as to cover the front surface 51a and the back surface 51b of the first wavelength conversion element 51. The second optical layer 62 has optical properties of transmitting the excitation light E and the fluorescence Y and reflecting the blue light B. The second optical layer 62 is formed, for example, of a dielectric multilayer film.

[0047] 2, the third optical layer 63 is disposed on the −X side of the first light source 41, the first optical layer 61, the light guiding unit 71, the first wavelength conversion element 51, and the second optical layer 62, and on the +X side of the second light source 42. The third optical layer 63 transmits the blue light B emitted from the second light source 42 and reflects the fluorescence Y. Specifically, the third optical layer 63 reflects the fluorescence Y that has propagated through the light guiding unit 71 and the first wavelength conversion element 51 and reached the third optical layer 63. The third optical layer 63 is formed, for example, from a dielectric multilayer film.

[0048] In the present embodiment, the third optical layer 63 is provided, via a light-transmitting substrate 63a, on an end face 73b on the first end face 51c side of the first light-transmitting member 73 that constitutes the light-guiding section 71 and on the first end face 51c of the first wavelength conversion element 51. The light-transmitting substrate 63a is made of the same material as the first light-transmitting member 73.

[0049] 3, the first reflecting member 81 is disposed on the third side wall 33e of the housing 31 so as to face the first side surface 51e of the first wavelength conversion element 51 and the area of ​​the light guiding unit 71 on the first side surface 51e side. The second reflecting member 82 is disposed on the fourth side wall 33f of the housing 31 so as to face the second side surface 51f of the first wavelength conversion element 51 and the area of ​​the light guiding unit 71 on the second side surface 51f side.

[0050] The first reflecting member 81 reflects the fluorescence Y and the excitation light E. Therefore, the first reflecting member 81 reflects the excitation light E that has passed through the first wavelength conversion element 51 or the light guiding section 71 and reached the first reflecting member 81, for example, and causes the excitation light E to enter the first wavelength conversion element 51. This makes it possible to increase the efficiency of conversion from the excitation light E to the fluorescence Y.

[0051] Furthermore, the first reflecting member 81 reflects and returns to the interior the fluorescence Y that has been emitted from the first wavelength conversion element 51, entered the light guiding section 71, and reached the first reflecting member 81, and the fluorescence Y that has been guided inside the first wavelength conversion element 51 and reached the first reflecting member 81. This makes it possible to suppress loss of the fluorescence Y.

[0052] Similarly, the second reflecting member 82 reflects the fluorescence Y and the excitation light E. The action and effect of the second reflecting member 82 are similar to those of the above-described first reflecting member 81. The first reflecting member 81 and the second reflecting member 82 are made of, for example, a metal film, a dielectric multilayer film, a scattering member, or the like.

[0053] 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.

[0054] The first lens array 91 has a plurality of first lenses 91a. The plurality of first lenses 91a are arranged in a matrix in a plane parallel to the YZ plane orthogonal to the optical axis AX1 of the illumination device 20. The plurality of first lenses 91a split the 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.

[0055] 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 in the vicinity of 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 illumination device 20. The superimposing optical system 94 is composed of a single convex lens.

[0056] 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.

[0057] 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.

[0058] The behavior of light in the light source device 30A of this embodiment will be described below. 2, in the light source device 30A, excitation light E emitted from one of the first light sources 41 arranged on the +Y side passes through the first optical layer 61, the light guiding section 71 (first light-transmissive member 73), and the second optical layer 62, and is incident on the surface 51a of the first wavelength conversion element 51. When the excitation light E 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.

[0059] The fluorescence Y incident on the front surface 51a and the back surface 51b of the first wavelength conversion element 51 at an incident angle less than the critical angle is emitted from the first wavelength conversion element 51, passes through the second optical layer 62, and enters the light guiding unit 71. The fluorescence Y that entered the light guiding unit 71 travels inside the first light-transmissive member 73, is reflected by the first optical layer 61, and enters the first wavelength conversion element 51 again. For example, the fluorescence Y1 propagates inside the first light-transmissive member 73 while being repeatedly reflected by the first optical layer 61 and the surface 51a of the first wavelength conversion element 51, and is emitted to the outside from the end face 73a of the first light-transmissive member 73 on the second end face 51d side. Although not shown in the figure, a portion of the fluorescence Y emitted from the back surface 51b of the first wavelength conversion element 51 propagates inside the first translucent member 73 while being repeatedly reflected by the first optical layer 61 and the back surface 51b of the first wavelength conversion element 51, and is emitted to the outside from the end face 73a on the second end face 51d side of the first translucent member 73.

[0060] Furthermore, the fluorescence Y2 is reflected by the first optical layer 61 and enters the first wavelength conversion element 51 again. In the present embodiment, the first wavelength conversion element 51 is made of a transparent phosphor, so that the fluorescence Y2 is not scattered inside the first wavelength conversion element 51 and the traveling direction of the fluorescence Y2 does not change inside the first wavelength conversion element 51. Therefore, the fluorescence Y2 enters the light guiding unit 71 from the back surface 51b of the first wavelength conversion element 51 and exits from the region on the second end surface 51d side of the light guiding unit 71.

[0061] Here, of the fluorescence Y emitted from the first wavelength conversion element 51, the fluorescence Y0 that is incident perpendicularly on the first optical layer 61 does not change its direction of travel inside the first wavelength conversion element 51 made of a transparent phosphor, and therefore is repeatedly reflected between the pair of first optical layers 61.

[0062] Furthermore, the fluorescence Y incident on the front surface 51a and the back surface 51b of the first wavelength conversion element 51 at an incident angle equal to or greater than the critical angle is totally reflected by the front surface 51a and the back surface 51b of the first wavelength conversion element 51. In the present embodiment, the first wavelength conversion element 51 is made of a transparent phosphor, and the traveling direction of the fluorescence Y does not change inside the first wavelength conversion element 51, so the incident angle of the fluorescence Y with respect to the front surface 51a and the back surface 51b of the first wavelength conversion element 51 does not change either. Therefore, the fluorescence Y is repeatedly reflected by total reflection inside the first wavelength conversion element 51.

[0063] In this way, the fluorescence Y emitted from the first wavelength conversion element 51 propagates through the first light-transmissive member 73 or the first wavelength conversion element 51, and is emitted from the region on the second end face 51d side of the first light-transmissive member 73 or the second end face 51d of the first wavelength conversion element 51. 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.

[0064] Furthermore, the fluorescence Y3 that travels toward the −X side and reaches the third optical layer 63 is reflected by the third optical layer 63, travels toward the +X side, and follows the same path as the fluorescence Y1 and Y2 described above. That is, the fluorescence Y3 propagates inside the first light-transmissive member 73 or the first wavelength conversion element 51, and is emitted from the region on the second end face 51d side of the first light-transmissive member 73 or the second end face 51d of the first wavelength conversion element 51.

[0065] On the other hand, blue light ray B emitted from the second light source 42 enters the third optical layer 63 via the translucent substrate 63a, transmits through the third optical layer 63, and enters the first wavelength conversion element 51 and the first translucent member 73. Here, the blue light ray B incident on the first translucent member 73 propagates inside the first translucent member 73 while being repeatedly reflected by the first optical layer 61 and 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. Note that part of the blue light ray B incident on the first wavelength conversion element 51 is converted into fluorescence Y, while the other part of the blue light ray B incident on the first wavelength conversion element 51 is converted into fluorescence Y. Therefore, part of the blue light beam B emitted from the second light source 42 travels inside the pair of first light-transmissive members 73 and is emitted from the end face 73a of the light-guiding section 71 on the second end face 51d side.

[0066] In this way, the light source device 30A of this embodiment can emit white illumination light WL containing the fluorescence Y generated by the first wavelength conversion element 51 and the blue light B emitted from the second light source 42 to the outside from the outlet 31K of the housing 31. Therefore, the light source device 30A has a small etendue for the illumination light WL, and can reduce loss of the illumination light WL in optical components such as the integrator optical system 90 arranged downstream of the light source device 30A. As a result, the utilization efficiency of the illumination light WL in the light source device 30A can be improved.

[0067] Furthermore, the light source device 30A of this embodiment can change the ratio between the amount of fluorescence Y and the amount of blue light B by appropriately adjusting the output of excitation light E emitted from the first light source 41 and the output of blue light B emitted from the second light source 42. This makes it possible to adjust the color temperature of the illumination light WL emitted from the light source device 30A. As a result, it is possible to adjust the color of the image projected by the projector 1.

[0068] (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 disposed between the first light source 41 and the first wavelength conversion element 51 and that transmits the excitation light E and reflects the fluorescence Y, a second light source 42 that emits blue light B in a blue wavelength band different from the yellow wavelength band, and a light guide unit 71 that is disposed between the first wavelength conversion element 51 and the first optical layer 61 and that guides the fluorescence Y converted by the first wavelength conversion element 51 and the blue light B emitted from the second light source 42. 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 surface 51c and a second end surface 51d that intersect with the surface 51a and face in opposite directions. The second light source 42 is disposed in a region of the light guide unit 71 on the side of the first end surface 51c. The first optical layer 61 reflects not only the fluorescence Y but also the blue light B emitted from the second light source 42. Some of the fluorescence Y converted by the first wavelength conversion element 51 and the blue light B emitted from the second light source 42 travel through the light guiding unit 71 and are emitted from a region of the light guiding unit 71 on the second end surface 51d side.

[0069] 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 a portion of the blue light beam B emitted from the second light source 42 travel through the light guide 71 and are emitted from the region on the second end face 51d side of the light guide 71. Therefore, compared to, for example, a conventional light source device in which all of the fluorescence propagates inside the wavelength conversion element, loss of the fluorescence Y is reduced, and the utilization efficiency of the fluorescence Y can be improved. Furthermore, the light source device 30A of the present embodiment can efficiently emit white illumination light WL obtained by combining the yellow fluorescence Y and the blue light beam B.

[0070] 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.

[0071] The projector 1 of this embodiment has excellent light utilization efficiency because it is equipped with the illumination device 20 including the light source device 30A that efficiently extracts the illumination light WL that includes the fluorescent light Y and Y1.

[0072] (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.

[0073] As shown in Figure 5, the light source device 30B of this embodiment includes a housing 31, a pair of first light sources 41, a first wavelength conversion element 53, a pair of first optical layers 61, a pair of second optical layers 62, a third optical layer 63, a pair of light guiding sections 71, a second light source 42, a first reflecting member (not shown), and a second reflecting member (not shown).

[0074] In the light source device 30A of the first embodiment, the first wavelength conversion element 51 is made of a transparent phosphor. In contrast, in the light source device 30B of the present embodiment, the first wavelength conversion element 53 is made of a phosphor having light-scattering properties. A phosphor having light-scattering properties can be realized by dispersing a medium having a refractive index different from that of the transparent phosphor, such as pores or a filler, in the transparent phosphor. The first wavelength conversion element 53 has a front surface 53a, a back surface 53b, a first end surface 53c, and a second end surface 53d. The other configuration of the light source device 30B is the same as that of the light source device 30A of the first embodiment. In this embodiment, the excitation light E emitted by the first light source 41 corresponds to an example of the "first blue light" of the present invention, and the blue light ray B emitted by the second light source 42 corresponds to an example of the "second blue light" of the present invention.

[0075] (Effects of the second embodiment) In this embodiment, too, the same effects as in the first embodiment can be obtained, such as that the fluorescence Y propagates through the light-guiding section 71, resulting in little loss of the fluorescence Y and realizing a light source device 30B with excellent utilization efficiency of the fluorescence Y, and realizing a light source device 30B that can efficiently emit the illumination light WL.

[0076] Here, in the case of the first embodiment, since the first wavelength conversion element 51 is made of a transparent phosphor, the direction of the fluorescence Y emitted from the first wavelength conversion element 51, of which the fluorescence Y0 (see Figure 2) that is incident perpendicularly on the first optical layer 61, is difficult to change inside the first wavelength conversion element 51, and is repeatedly reflected between the pair of first optical layers 61, resulting in light loss without being extracted to the outside.

[0077] 5, when the fluorescence Y enters the first wavelength conversion element 53, a large amount of scattering occurs, and the traveling direction of the fluorescence Y changes with each scattering. For this reason, even if the fluorescence Y0 is perpendicularly incident on the first optical layer 61 and reflected, it is 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.

[0078] Furthermore, in the case of the first embodiment, the fluorescence trapped inside the first wavelength conversion element 51 by repeated total reflection also scatters in the first wavelength conversion element 53, so that the traveling direction of the fluorescence changes each time it is scattered. Therefore, in the configuration of the first embodiment, the fluorescent component trapped inside the first wavelength conversion element 51 can be extracted to the outside of the first wavelength conversion element 51 by angle conversion caused by scattering.

[0079] As described above, according to the configuration of this embodiment, the fluorescence Y can be emitted from the end face 73a located in the area on the second end face 51d side of the first light-transmissive member 73 while being repeatedly scattered by the first wavelength conversion element 53 and reflected by the first optical layer 61. Therefore, according to the light source device 30B of this embodiment, the fluorescence Y can be extracted more efficiently as illumination light WL.

[0080] (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.

[0081] As shown in Figure 6, the light source device 30C of this embodiment includes a housing 31, a pair of first light sources 41, a first wavelength conversion element 51, a pair of first optical layers 61, a pair of second optical layers 62, a third optical layer 63, a pair of light-guiding sections 76, a second light source 42, a first reflecting member (not shown), and a second reflecting member (not shown).

[0082] In the light source device 30C of this embodiment, each of the pair of light guiding sections 76 is formed of an air layer 77. The second optical layer 62 is provided on each of the front surface 51a and the back surface 51b of the first wavelength conversion element 51. In this embodiment, the fluorescence Y converted by the first wavelength conversion element 51 and the blue light B emitted from the second light source 42 travel through the air layer 77 and are emitted from a region of the air layer 77 on the second end surface 51d side.

[0083] In this embodiment, each first optical layer 61 is provided on a light-transmitting substrate 161a having optical transparency. The first optical layer 61 is provided on the surface of the light-transmitting substrate 161a facing the first wavelength conversion element 51. The light-transmitting substrate 161a is made of the same material as the first light-transmitting member 73. The other configurations of the light source device 30C are similar to those of the light source device 30A of the first embodiment.

[0084] The behavior of light in the light source device 30C of this embodiment will be described below. As shown in FIG. 6, in the light source device 30C, the excitation light E emitted from the first light source 41 passes through the first optical layer 61 and enters the first wavelength conversion element 51. When the excitation light E 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.

[0085] The fluorescence Y incident on the front surface 51a or the back surface 51b of the first wavelength conversion element 51 at an incident angle less than the critical angle is emitted from the first wavelength conversion element 51, passes through the second optical layer 62, and travels through the air layer 77. For example, the fluorescence Y4 is directly emitted to the outside from the end surface 73a on the second end surface 51d side of the air layer 77. The fluorescence Y5 propagates inside the air layer 77 while being repeatedly reflected by the first optical layer 61 and the surface 51a of the first wavelength conversion element 51, and is emitted from the region of the light-guiding section 76 on the second end surface 51d side.

[0086] The blue light ray B emitted from the second light source 42 and incident on the light guide section 76 propagates through the air layer 77 while being repeatedly reflected by the first optical layer 61 and 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 air layer 77.

[0087] (Effects of the third embodiment) In this embodiment, too, the fluorescence Y propagates through the light-guiding section 76, which reduces the loss of the fluorescence Y and makes it possible to realize a light source device 30C that is excellent in the efficiency of using the fluorescence Y, and which can efficiently emit the illumination light WL, thereby achieving the same effects as in the first embodiment.

[0088] In the present embodiment, the light guide section 76 that guides the fluorescent light Y and the blue light B 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 as the light guiding section 76 as in the present embodiment, the refractive index difference between the first wavelength conversion element 51 and the air layer 77 is approximately 0.7 because the refractive index of YAG constituting the wavelength conversion element is approximately 1.7 and the refractive index of air is approximately 1.0. On the other hand, for example, when the first light-transmissive member 73 is made of quartz (refractive index 1.4), the refractive index difference between the first wavelength conversion element 51 and the light guiding section 71 in the first embodiment is approximately 0.3, and the refractive index difference in this embodiment is larger than the refractive index difference in the first embodiment. Therefore, the fluorescence Y emitted from the first wavelength conversion element 51 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 emitted into the air layer 77 travels along the optical axis AX1, making it easier to extract from the extraction port 31K.

[0089] Furthermore, in the case of this embodiment, the air layer 77 is open to the external space at the outlet 31K and does not have a refractive index interface, so the fluorescence Y that reaches the outlet 31K is emitted directly into the external space without being reflected or refracted. Due to the above-mentioned effects, the light source device 30C of this embodiment can further increase the extraction efficiency of the fluorescence Y compared to the first embodiment.

[0090] (Fourth embodiment) A light source device according to a fourth embodiment of the present invention will be described below with reference to FIGS. Fig. 7 is a cross-sectional view of the light source device 130 of the fourth embodiment cut in the XY plane. Fig. 8 is a cross-sectional view of the light source device 130 along line VIII-VIII in Fig. 7. Fig. 9 is a plan view of the light source device 130 viewed from the +X side to the -X side. That is, Fig. 9 is a plan view when viewed in the X-axis direction, which is the normal direction of the second end face 51d along the YZ plane of the first wavelength conversion element 51. In Figs. 7, 8, and 9, components common to those in the drawings used in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0091] 7 and 8 , the light source device 130 of this embodiment includes a housing 31, a pair of first light sources 41, a first wavelength conversion element 51, a first optical layer 161, a light guide 171, a second light source 42, a second wavelength conversion element 52, the second optical layer 162, a third optical layer 163, a fourth optical layer 164, a fifth optical layer 165, a first reflecting member 81, and a second reflecting member 82. In the light source device 130 of this embodiment, the housing 31 has an extraction port 31K for extracting light emitted from the light guide 171, the first wavelength conversion element 51, and the second wavelength conversion element 52 to the outside.

[0092] 9, the outlet 31K overlaps the light guiding section 171, the first wavelength conversion element 51, and the second wavelength conversion element 52. Specifically, the outlet 31K of this embodiment has a shape that exposes the light guiding section 171, the third optical layer 163, the fourth optical layer 164, the first wavelength conversion element 51, and the second wavelength conversion element 52 to the inside, but does not expose the first optical layer 161 and the second optical layer 162 to the inside. Note that the outlet 31K may have a shape that exposes the first optical layer 161 and the second optical layer 162 to the inside.

[0093] The light source device 130 of this embodiment can efficiently extract white light containing the fluorescence Y and blue light B propagated inside the light-guiding section 171, the fluorescence Y emitted from the first wavelength conversion element 51, and the fluorescence Y1 emitted from the second wavelength conversion element 52 as illumination light WL through the extraction port 31K of the housing 31.

[0094] 7, one first light source 41 emits excitation light E toward the first wavelength conversion element 51, and the other first light source 41 emits excitation light E toward the second wavelength conversion element 52. In the following description, one of the pair of first light sources 41 may be referred to as the first light source 41a, the excitation light E emitted from the first light source 41a as the first excitation light E1, the other of the pair of first light source 41 as the first light source 41b, and the excitation light E emitted from the first light source 41b as the second excitation light E2.

[0095] The first optical layer 161 is disposed between the first light source 41a and the first wavelength conversion element 51. The first optical layer 161 has optical properties of transmitting the first excitation light E1 and reflecting the fluorescence Y. The first optical layer 161 of this embodiment reflects the fluorescence Y generated by the first wavelength conversion element 51 and the fluorescence Y1 generated by the second wavelength conversion element 52, as well as the blue light ray B emitted from the second light source 42. The first optical layer 161 is formed of, for example, a dielectric multilayer film. The first optical layer 161 is provided on a surface of the first wavelength conversion element 51 facing the first light source 41a.

[0096] 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 171 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. 7.

[0097] 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.

[0098] 7, 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.

[0099] 8, 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.

[0100] In the present embodiment, the first wavelength conversion element 51 converts the second excitation light E2 emitted from the first light source 41b and transmitted through the second optical layer 162, the second wavelength conversion element 52, and the light-guiding section 171, and the first excitation light E1 emitted from the first light source 41a and transmitted through the first optical layer 161, into yellow fluorescence Y of a second wavelength band different from the first wavelength band. The first excitation light E1 and the second excitation light E2 of the present embodiment correspond to an example of the "first light of the first wavelength band" of the present invention, and the yellow fluorescence Y of the present embodiment corresponds to an example of the "second light" of the present invention.

[0101] The second wavelength conversion element 52 converts the first excitation light E1 emitted from the first light source 41a and transmitted through the first optical layer 161, the first wavelength conversion element 51, and the light-guiding section 171, and the second excitation light E2 emitted from the first light source 41b and transmitted through the second optical layer 162 (described later), 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.

[0102] 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.

[0103] The second optical layer 162 is disposed on the opposite side of the second wavelength conversion element 52 from the light guiding section 171. The second optical layer 62 is disposed on the opposite side of the second wavelength conversion element 52 from the light guiding section 71, and has the optical property of transmitting the second excitation light E2 and reflecting the fluorescence Y and Y1. The second optical layer 162 of this embodiment reflects the fluorescence Y generated by the first wavelength conversion element 51 and the fluorescence Y1 generated by the second wavelength conversion element 52, as well as the blue light ray B emitted from the second light source 42. The second optical layer 162 is formed of, for example, a dielectric multilayer film. The second optical layer 162 is provided on a surface of the second wavelength conversion element 52 facing the first light source 41b.

[0104] The light guiding unit 171 is disposed on the opposite side of the first wavelength conversion element 51 from the first optical layer 161, and guides incident light. Specifically, the light guiding unit 171 is disposed between the first wavelength conversion element 51 and the second wavelength conversion element 52. The light guiding unit 171 guides the fluorescence Y converted by the first wavelength conversion element 51, the fluorescence Y1 converted by the second wavelength conversion element 52, and some of the blue light B emitted from the second light source 42. In the present embodiment, a first light-transmissive member 73 that transmits the first excitation light E1, the second excitation light E2, the fluorescence Y and Y1, and the blue light B is disposed in the light guiding unit 171.

[0105] The third optical layer 163 is disposed between the first wavelength conversion element 51 and the light guiding section 171. The fourth optical layer 164 is disposed between the second wavelength conversion element 52 and the light guiding section 171. In the present embodiment, the third optical layer 163 is provided on the back surface 51b of the first wavelength conversion element 51, and the fourth optical layer 164 is provided on the back surface 52b of the second wavelength conversion element 52. The third optical layer 163 and the fourth optical layer 164 transmit the first excitation light E1, the second excitation light E2, and the fluorescence Y and Y1, and reflect the blue light B. The third optical layer 163 and the fourth optical layer 164 are formed, for example, of a dielectric multilayer film.

[0106] In this embodiment, the second light source 42 emits blue light B toward the first wavelength conversion element 51, the second wavelength conversion element 52, and the first translucent member 73. The blue light B in this embodiment corresponds to the "fourth light in the fourth wavelength band" of the present invention. In this embodiment, the fourth wavelength band of the blue light B is wider than the first wavelength bands of the first excitation light E1 and the second excitation light E2. The second wavelength band of the fluorescence Y and the third wavelength band of the fluorescence Y1 are wider than the fourth wavelength band of the blue light B.

[0107] 7 , the fifth optical layer 165 is disposed on the −X side of the first light source 41, the first wavelength conversion element 51, the first optical layer 161, the light guide 171, the second light source 42, the second wavelength conversion element 52, the second optical layer 162, the third optical layer 163, and the fourth optical layer 164, and on the +X side of the second light source 42. The fifth optical layer 165 transmits the blue light B emitted from the second light source 42 and reflects the fluorescence Y and Y1. Specifically, the fifth optical layer 165 reflects the fluorescence Y and Y1 that has propagated through the light guide 171, the first wavelength conversion element 51, and the second wavelength conversion element 52 and reached the fifth optical layer 165. The fifth optical layer 165 is formed, for example, from a dielectric multilayer film.

[0108] In the present embodiment, the fifth optical layer 165 is provided, via a light-transmitting substrate 165a, on an end face 73b on the first end face 51c side of the first light-transmitting member 73 that constitutes the light-guiding section 171, the first end face 51c of the first wavelength conversion element 51, and the first end face 52c of the second wavelength conversion element 52. The light-transmitting substrate 165a is made of the same material as the first light-transmitting member 73.

[0109] 8, the first reflecting member 81 is disposed on the third side wall 33e of the housing 31 so as to face the first side surface 51e of the first wavelength conversion element 51 and the area of ​​the light guiding unit 171 on the first side surface 51e side. The second reflecting member 82 is disposed on the fourth side wall 33f of the housing 31 so as to face the second side surface 51f of the first wavelength conversion element 51 and the area of ​​the light guiding unit 171 on the second side surface 51f side.

[0110] The first reflecting member 81 reflects the first excitation light E1, the second excitation light E2, the fluorescence Y and Y1, and the blue light B. Therefore, the first reflecting member 81 reflects the first excitation light E1 that has passed through the first wavelength conversion element 51 or the light guiding section 171 and reached the first reflecting member 81, and causes the first excitation light E1 to enter the first wavelength conversion element 51. This can increase the efficiency of conversion from the first excitation light E1 to the fluorescence Y. Furthermore, the first reflecting member 81 reflects the second excitation light E2 that has passed through the second wavelength conversion element 52 or the light guiding section 171 and reached the first reflecting member 81, and causes the second excitation light E2 to enter the second wavelength conversion element 52. This can increase the efficiency of conversion from the second excitation light E2 to fluorescence Y1.

[0111] Furthermore, the first reflecting member 81 reflects and returns to the inside the fluorescence Y that is emitted from the first wavelength conversion element 51, enters the light guiding section 171, and reaches the first reflecting member 81, and the fluorescence Y that is guided inside the first wavelength conversion element 51 and reaches the first reflecting member 81. This makes it possible to suppress loss of the fluorescence Y. Furthermore, the first reflecting member 81 reflects and returns to the inside the fluorescence Y1 that has been emitted from the second wavelength conversion element 52, entered the light guiding section 171, and reached the first reflecting member 81, and the fluorescence Y1 that has been guided inside the second wavelength conversion element 52 and reached the first reflecting member 81. This makes it possible to suppress loss of the fluorescence Y1.

[0112] Similarly, the second reflecting member 82 reflects the first excitation light E1, the second excitation light E2, the fluorescence Y and Y1, and the blue light B. The action and effect of the second reflecting member 82 are similar to those of the above-described first reflecting member 81. The first reflecting member 81 and the second reflecting member 82 are made of, for example, a metal film, a dielectric multilayer film, a scattering member, or the like.

[0113] The behavior of light in the light source device 130 of this embodiment will be described below. 7, in the light source device 130, the first excitation light E1 emitted from the first light source 41a arranged on the +Y side passes through the first optical layer 161 and is incident on the surface 51a of 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.

[0114] The fluorescence Y emitted from the first wavelength conversion element 51 is reflected by the first optical layer 161, or is directly incident on the back surface 51b of the first wavelength conversion element 51 without being reflected by the first optical layer 161. At this time, the fluorescence Y01 incident on the back surface 51b at an incident angle less than the critical angle is emitted from the first wavelength conversion element 51, passes through the third optical layer 163, enters the light guiding section 171, and is emitted to the outside from the end surface 73a of the first light-transmissive member 73 on the second end surface 51d side. Furthermore, the fluorescence Y02 emitted from the first wavelength conversion element 51 and incident on the rear surface 51b at an incident angle less than the critical angle is transmitted through the first light-transmissive member 73, the fourth optical layer 164, and the second wavelength conversion element 52, reflected by the second optical layer 162, transmitted through the first light-transmissive member 73, the third optical layer 163, and the first wavelength conversion element 51 in that order, reflected again by the first optical layer 161, and emitted to the outside from the end surface 73a on the second end surface 51d side of the first light-transmissive member 73. Although not shown in the drawings, part of the fluorescence Y incident on the first light-transmissive member 73 is reflected by the rear surface 52b of the second wavelength conversion element 52, enters the first light-transmissive member 73 again, and is emitted to the outside from the end surface 73a on the second end surface 51d side of the first light-transmissive member 73.

[0115] Furthermore, the fluorescence Y03 emitted from the first wavelength conversion element 51 and reaching the fifth optical layer 165 is reflected by the fifth optical layer 165, then travels toward the +X side, and is reflected by, for example, the first optical layer 161 and the second optical layer 162, 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.

[0116] 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 161 and the second wavelength conversion element 52 or the second optical layer 162, 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.

[0117] On the other hand, the second excitation light E2 emitted from the second light source 42 passes through the second optical layer 162 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, so a detailed description thereof will be omitted.

[0118] Therefore, in the light source device 130 of this 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 171 and are emitted from the end surface 73a of the first light-transmissive member 73. Therefore, according to the light source device 30A of this embodiment, the illumination light WL including the fluorescence Y and Y1 can be efficiently extracted to the outside from the extraction port 31K of the housing 31.

[0119] On the other hand, blue light B emitted from the second light source 42 enters the fifth optical layer 165 through the translucent substrate 165a, passes through the fifth optical layer 165, and enters the first wavelength conversion element 51, the second wavelength conversion element 52, and the first translucent member 73.

[0120] Here, the blue light ray B incident on the first light-transmissive member 73 propagates inside the first light-transmissive member 73 while being repeatedly reflected by the third optical layer 163 and the fourth optical layer 164, 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. Note that a portion of the blue light ray B incident on the first wavelength conversion element 51 is converted into fluorescence Y while propagating inside the first wavelength conversion element 51 while being repeatedly reflected by the first optical layer 61 and the third optical layer 163. Similarly, a portion of the blue light ray B incident on the second wavelength conversion element 52 is converted into fluorescence Y1 while propagating inside the second wavelength conversion element 52 while being repeatedly reflected by the second optical layer 62 and the fourth optical layer 164. Therefore, part of the blue light beam B emitted from the second light source 42 travels inside the first light-transmissive member 73 and is emitted from the region of the light-guiding portion 171 on the second end surface 52d side.

[0121] (Effects of the fourth embodiment) The light source device 130 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 171 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 171 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 171 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 171 and that reflects the fluorescence Y and the fluorescence Y1; and a second light source 42 that emits blue light B. 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 surface 51c and a second end surface 51d that intersect with the surface 51a and face in opposite directions. The second light source 42 is disposed in a region of the light guiding unit 171 on the second end surface 51d side, and the first optical layer 61 and the second optical layer 62 reflect the blue light ray B emitted from the second light source 42 in addition to the fluorescence Y and the fluorescence Y1. Some of the fluorescence Y converted by the first wavelength conversion element 51, the fluorescence Y1 converted by the second wavelength conversion element 52, and the blue light ray B emitted from the second light source 42 travel through the light guiding unit 71 and are emitted from a region of the light guiding unit 71 on the second end surface 51d side.

[0122] According to the light source device 130 of this embodiment, the fluorescence Y generated by the first wavelength conversion element 51, the fluorescence Y1 generated by the second wavelength conversion element 52, and the blue light ray B emitted from the second light source 42 travel through the light guiding unit 171 and are emitted from the region on the second end face 52d side of the light guiding unit 171. Therefore, compared to, for example, a conventional light source device in which all fluorescence propagates inside the wavelength conversion element, loss of the fluorescence Y and Y1 is small, and the utilization efficiency of the fluorescence Y and Y1 can be improved. Furthermore, the light source device 130 of this embodiment can efficiently emit white illumination light WL obtained by combining the yellow fluorescence Y and Y1 and the blue light ray B.

[0123] (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 fourth embodiment, so a description of the basic configuration of the light source device will be omitted. Fig. 10 is a cross-sectional view of a light source device 130A of the fifth embodiment cut along the XY plane. In Fig. 10, components common to those in the fourth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0124] As shown in FIG. 10, the light source device 130A of this embodiment includes a housing 31, a pair of first light sources 41, a first wavelength conversion element 53, a first optical layer 161, a light guide section 171, a second light source 42, a second wavelength conversion element 54, a second optical layer 162, a third optical layer 163, a fourth optical layer 164, a fifth optical layer 165, a first reflecting member (not shown), and a second reflecting member (not shown).

[0125] In the light source device 130 of the fourth embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 are made of transparent phosphors. In contrast, the light source device 130A of the present embodiment has a first wavelength conversion element 53 and a second wavelength conversion element 54 made of light-scattering phosphors, similar to the light source device 30B of the second embodiment. The other configuration of the light source device 130A is similar to that of the light source device 130 of the fourth embodiment. In the present embodiment, the first excitation light E1 emitted by the first light source 41a and the second excitation light E2 emitted by the first light source 41b correspond to an example of the "first blue light" of the present invention, and the blue light ray B emitted by the second light source 42 corresponds to an example of the "second blue light" of the present invention.

[0126] (Effects of the fifth embodiment) In this embodiment, too, the fluorescence Y, Y1 propagates through the light-guiding section 171, thereby achieving the same effects as in the fourth embodiment, such as reducing the loss of the fluorescence Y, Y1 and realizing a light source device 130A that has excellent utilization efficiency of the fluorescence Y, Y1, and that can efficiently emit the illumination light WL.

[0127] In the fourth 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 that is perpendicularly incident on the first optical layer 161 is unlikely to change inside the first wavelength conversion element 51 and the second wavelength conversion element 52, and the fluorescence is repeatedly reflected between the first optical layer 161 and the second optical layer 162, resulting in loss. The same applies to the fluorescence Y1 emitted from the second wavelength conversion element 52.

[0128] In contrast to this, in the case of the present embodiment, since the first wavelength conversion element 53 and the second wavelength conversion element 54 are made of phosphors having light scattering properties, a lot of scattering occurs when the fluorescence Y is incident on the first wavelength conversion element 53 or the second wavelength conversion element 52, and the traveling direction of the fluorescence Y changes with each scattering. For this reason, even if the fluorescence Y0 is emitted in a direction perpendicular to the first optical layer 61, for example, the angle of the fluorescence Y0 is converted by being scattered by the second wavelength conversion element 54, and the fluorescence Y0 is eventually emitted from the end face 73 a of the first light-transmissive member 73.

[0129] Furthermore, in the configuration of the fourth embodiment, the fluorescence Y, Y1 trapped inside the first wavelength conversion element 51 or the second wavelength conversion element 52 due to repeated total reflection also undergoes a large amount of scattering within each wavelength conversion element 53, 54, and the traveling direction of the fluorescence Y, Y1 can be changed with each scattering. In this manner, the fluorescence Y, Y1 propagates through the light guiding unit 171 while repeatedly undergoing at least one of scattering by the first wavelength conversion element 53, reflection by the first optical layer 161, scattering by the second wavelength conversion element 54, and reflection by the second optical layer 162, and is emitted from the region on the second end face 51d side of the light guiding unit 171. Furthermore, the blue light ray B emitted from the second light source 42 propagates through the light guiding unit 171 while repeatedly being reflected by the third optical layer 163 and the fourth optical layer 164, and is emitted from the region on the second end face 51d side of the light guiding unit 171. Therefore, according to the light source device 130A of this embodiment, the fluorescent light Y, Y1 can be extracted more efficiently as the illumination light WL.

[0130] (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 fourth embodiment, so a description of the basic configuration of the light source device will be omitted. 11 is a cross-sectional view of a light source device 130B according to the sixth embodiment cut along the XY plane. In FIG. 11, components common to those in the fourth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0131] As shown in FIG. 11, the light source device 130B of this embodiment includes a housing 31, a pair of first light sources 41, a first wavelength conversion element 51, a first optical layer 161, a light guide section 176, a second light source 42, a second wavelength conversion element 52, a second optical layer 162, a third optical layer 163, a fourth optical layer 164, a fifth optical layer 165, a first reflecting member (not shown), and a second reflecting member (not shown).

[0132] The light guiding section 176 is formed from an air layer 177. 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 176 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. The second light source 42 is disposed in a region on the first end surface 51c side of the light guiding section 176. The other configurations of the light source device 130B are similar to those of the light source device 130 of the fourth embodiment.

[0133] The behavior of light in the light source device 130B of this embodiment will be described below. As shown in FIG. 11, in the light source device 130B, the first excitation light E1 emitted from the first light source 41a 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.

[0134] Fluorescence Y04 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 177, and then is emitted to the outside from the area on the second end surface 51d side of the air layer 177.

[0135] 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.

[0136] The fluorescence Y05 emitted from the first wavelength conversion element 51 travels through the air layer 177 toward the +X side, passes through the fourth optical layer 164 and enters the second wavelength conversion element 52. After traveling through the air layer 177 while being repeatedly reflected by the second optical layer 62 and the first optical layer 61, the fluorescence Y05 is emitted to the outside from the area on the second end face 51d side of the air layer 177.

[0137] The fluorescence Y06 emitted from the first wavelength conversion element 51 travels through the air layer 177 toward the -X side and enters the fifth optical layer 165. The fluorescence Y06 is reflected by the fifth optical layer 165, travels through the air layer 177 while being repeatedly reflected by the second optical layer 62 and the first optical layer 61, and is then emitted to the outside from the area on the second end face 51d side of the air layer 177.

[0138] 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.

[0139] 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, so a detailed description thereof will be omitted.

[0140] Therefore, in the light source device 130B 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 air layer 177 of the light guiding section 176 and are emitted from the end surface 73a of the first light-transmissive member 73. Therefore, according to the light source device 130B of the present embodiment, the illumination light WL including the fluorescence Y and Y1 can be efficiently extracted to the outside from the extraction port 31K of the housing 31.

[0141] On the other hand, blue light B emitted from the second light source 42 enters the fifth optical layer 165 through the translucent substrate 165a, passes through the fifth optical layer 165, and enters the first wavelength conversion element 51, the second wavelength conversion element 52, and the air layer 177.

[0142] (Effects of the sixth embodiment) In this embodiment, too, the fluorescence Y, Y1 propagates through the light-guiding section 176, which reduces the loss of the fluorescence Y, Y1 and makes it possible to realize a light source device 130B that is excellent in the efficiency of using the fluorescence Y, Y1, and that can efficiently emit the illumination light WL, thereby achieving the same effects as in the fourth embodiment.

[0143] In the present embodiment, the light guide section 176 that guides the fluorescent light Y, Y1 and the blue light B is configured with the air layer 177, and therefore the following effects can be obtained. When an air layer 177 is provided adjacent to the first wavelength conversion element 51 and the second wavelength conversion element 52 as the light guiding section 176 as in the present embodiment, the refractive index difference between the first wavelength conversion element 51 and the air layer 177 is approximately 0.7 because the refractive index of YAG constituting the wavelength conversion element is approximately 1.7 and the refractive index of air is approximately 1.0. On the other hand, for example, when the first light-transmissive member 73 is made of quartz (refractive index 1.4), the refractive index difference between the first wavelength conversion element 51 and the light guiding section 71 in the fourth embodiment is approximately 0.3, and the refractive index difference in this embodiment is larger than the refractive index difference in the fourth embodiment. Therefore, the fluorescence Y emitted from the first wavelength conversion element 51 and incident on the air layer 177 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 emitted into the air layer 177 travels along the optical axis AX1, making it easier to extract from the extraction port 31K.

[0144] Furthermore, in the case of the present embodiment, the air layer 177 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 effects, the light source device 130B of the present embodiment can further increase the extraction efficiency of the fluorescence Y, Y1 compared to the fourth embodiment.

[0145] In this embodiment, the first wavelength conversion element 51 and the second wavelength conversion element 52 may be replaced with a first wavelength conversion element 53 and a second wavelength conversion element 54 made of a phosphor having light scattering properties. According to this configuration, the traveling direction of the fluorescence Y, Y1 is changed by scattering, and the fluorescence Y, Y1 can be extracted more efficiently.

[0146] (Seventh embodiment) The seventh embodiment of the present invention will be described below with reference to FIG. The basic configuration of the light source device of the seventh embodiment is the same as that of the fifth embodiment, and therefore a description of the basic configuration of the light source device will be omitted. Fig. 12 is a cross-sectional view of a light source device 130C of the seventh embodiment cut along the XY plane. In Fig. 12, components common to those in the fourth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

[0147] As shown in FIG. 12, the light source device 130C of this embodiment includes a housing 31, a pair of first light sources 41, a first wavelength conversion element 53, a first optical layer 161, a light-guiding section 176, a second light source 42, a second wavelength conversion element 54, a second optical layer 162, a third optical layer 163, a fourth optical layer 164, a fifth optical layer 165, a light-transmitting substrate 161a, a light-transmitting substrate 162a, a light-transmitting substrate 163a, a light-transmitting substrate 164a, a first reflecting member (not shown), and a second reflecting member (not shown). Other configurations of the light source device 130C are similar to the configuration obtained by combining the light source device 130A of the fifth embodiment and the light source device 130B of the sixth embodiment.

[0148] In the light source device 130 of the fourth embodiment, the first optical layer 161 is provided on the surface 51a of the first wavelength conversion element 51, and the second optical layer 162 is provided on the surface 52a of the second wavelength conversion element 52. In contrast, in the light source device 130C of the present embodiment, a light-transmitting substrate 161a is arranged between the first optical layer 161 and the first wavelength conversion element 51, and a light-transmitting substrate 162a is arranged between the second optical layer 162 and the second wavelength conversion element 52.

[0149] In the light source device 130 of the fourth embodiment, the third optical layer 163 is provided on the back surface 51b of the first wavelength conversion element 51, and the fourth optical layer 164 is provided on the back surface 52b of the second wavelength conversion element 52. In contrast, in the light source device 130C of the present embodiment, a light-transmitting substrate 163a is disposed between the third optical layer 163 and the first wavelength conversion element 51, and a light-transmitting substrate 164a is disposed between the second optical layer 162 and the second wavelength conversion element 52. The light-transmitting substrates 161a to 164a are made of the same material as the first light-transmitting member 73 of the first embodiment.

[0150] (Effects of the Seventh Embodiment) In this embodiment, too, the fluorescence Y, Y1 propagates through the light-guiding section 176, which reduces the loss of the fluorescence Y, Y1 and makes it possible to realize a light source device 130C that is excellent in the efficiency of using the fluorescence Y, Y1, and that can efficiently emit the illumination light WL, thereby achieving the same effects as in the fourth embodiment.

[0151] The light source device 130C of this embodiment has a first wavelength conversion element 53 and a second wavelength conversion element 54 made of a phosphor having light scattering properties. The first wavelength conversion element 53 and the second wavelength conversion element 54 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.

[0152] In contrast, in the light source device 130C of this embodiment, the first optical layer 161, the second optical layer 162, the third optical layer 163, and the fourth optical layer 164 are formed on each of the light-transmitting substrates 161a to 164a, so that each of the optical layers 161 to 164 can be formed from a flat film, thereby improving the optical properties of each of the optical layers 161 to 164. Therefore, in the light source device 130C 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 each of the optical layers 161 to 164 having excellent optical properties.

[0153] In the light source device 130C of this embodiment, heat from the first wavelength conversion element 53 is efficiently dissipated through the light-transmitting substrates 161a and 163a, and heat from the second wavelength conversion element 54 is efficiently dissipated through the light-transmitting substrates 162a and 164a. This improves the cooling performance of the first wavelength conversion element 53 and the second wavelength conversion element 54, improving the fluorescence conversion efficiency of the first wavelength conversion element 53 and the second wavelength conversion element 54, and enabling the generation of bright fluorescence Y and Y1.

[0154] The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, a composite phosphor containing AlN and Ce:YAG may be used as the constituent material of the first wavelength conversion element. With this configuration, even if the contact area between the first wavelength conversion element and the housing is small and many heat dissipation paths cannot be ensured, the thermal conductivity of the first wavelength conversion element can be increased compared to when a phosphor consisting solely of Ce:YAG is used. This improves the cooling efficiency of the first wavelength conversion element. This increases the maximum light intensity of the first excitation light and the maximum output of yellow fluorescence. Similarly, a composite phosphor may also be used for the second wavelength conversion element.

[0155] Furthermore, in the above-described embodiments, an LED is used as the second light source, but a laser light-emitting element may also be used. In this case, the laser light-emitting element has a smaller emission angle than an LED, and the emitted light passes directly through the interior of the light-guiding section. Therefore, in the first to third embodiments, the second optical layer provided between the first wavelength conversion element and the light-guiding section can be omitted. Furthermore, in the fourth to seventh embodiments, the third optical layer provided between the first wavelength conversion element and the light-guiding section and the fourth optical layer provided between the second wavelength conversion element and the light-guiding section can be omitted.

[0156] 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.

[0157] 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.

[0158] Summary of this disclosure A summary of this disclosure is provided below.

[0159] (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 second light source that emits third light in a third wavelength band different from the second wavelength; a light guiding section disposed between the first wavelength conversion element and the first optical layer, which guides the second light converted by the first wavelength conversion element and the third light emitted from the second light source; Equipped with the first wavelength conversion element has a first surface onto which the first light is incident via the first optical layer, and a second surface and a third surface that intersect with the first surface and face in opposite directions to each other; the second light source is disposed in an area on the second surface side of the light guide section, the first optical layer reflects the third light emitted from the second light source in addition to the second light, the second light converted by the first wavelength conversion element and a part of the third light emitted from the second light source 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.

[0160] According to the light source device having this configuration, the second light generated by the first wavelength conversion element and a portion of the third light emitted from the second light source travel through the light guide and are emitted from the region on the third surface side of the light guide. Therefore, compared to, for example, a conventional light source device in which all of the fluorescence propagates inside the first wavelength conversion element, the loss of the second light is reduced, and the utilization efficiency of the second light can be improved. Furthermore, the light source device having this configuration can efficiently emit illumination light in which the second light in the second wavelength band and the third light in the third wavelength band are combined.

[0161] (Appendix 2) Further comprising a second optical layer disposed between the first wavelength conversion element and the light guiding portion, the third wavelength of the third light is greater than the first wavelength of the first light, the second wavelength of the second light is greater than the third wavelength of the third light; the second optical layer transmits the first light and the second light and reflects the third light; 10. The light source device of claim 1.

[0162] According to this configuration, the third light is reflected by the second optical layer, so that the third light can be effectively propagated inside the light-guiding unit. Furthermore, for example, by using yellow fluorescent light as the second light and blue light as the third light, the second light and the third light can be combined to generate white illumination light.

[0163] (Appendix 3) the first wavelength conversion element is made of a yellow phosphor having light scattering properties, the first light is a first blue light; the second light is yellow fluorescent light, the third light is a second blue light; the fluorescence propagates through the light guiding unit while being repeatedly scattered by the first wavelength conversion element and reflected by the first optical layer, and is emitted from a region of the light guiding unit on the third surface side, the second blue light propagates through the light guiding unit while repeatedly being reflected by the first optical layer and the second optical layer, and is emitted from a region of the light guiding unit on the third surface side. 10. The light source device according to claim 2.

[0164] According to this configuration, the propagation direction of the second light changes in various directions due to the scattering of light by the first wavelength conversion element, and the second light can be efficiently emitted from the region on the third surface side after propagating inside the light guiding unit. Therefore, loss of the second light can be reduced, and the extraction efficiency of the second light can be further improved. In addition, white illumination light obtained by combining the yellow fluorescence generated by the first wavelength conversion element and the second blue light emitted from the second light source can be efficiently extracted from the third surface side of the light guiding unit.

[0165] (Appendix 4) a third optical layer disposed at least between the second light source and a region on the second surface side of the light guiding section, the third optical layer transmitting the third light and reflecting the second light; 4. A light source device according to any one of claims 1 to 3.

[0166] According to this configuration, the second light is reflected by the third optical layer and the third light is transmitted, so that the second light and the third light can be efficiently emitted from the region on the third surface side of the light guide section.

[0167] (Appendix 5) further comprising a housing that accommodates the first optical layer and the first wavelength conversion element; the housing has an outlet through which the second light and the third light 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 unit and the first wavelength conversion element. 5. A light source device according to any one of claims 1 to 4.

[0168] According to this configuration, the first optical layer and the first wavelength conversion element can be protected by the housing, and the light propagating inside the light guide can be extracted as illumination light from the extraction port to the outside. Furthermore, since the etendue of the illumination light is reduced, loss of the illumination light in the optical members arranged downstream of the light source device can be reduced.

[0169] (Appendix 6) 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 a portion of the third light emitted from the second light source 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. 6. A light source device according to any one of claims 1 to 5.

[0170] According to this configuration, since the first light-transmitting member is disposed in the light guiding section, the refractive index difference between the first 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 therefore the critical angle at the interface between the first wavelength conversion element and the light guiding section is smaller, which makes it easier to extract the second light generated by the first wavelength conversion element into the light guiding section, thereby suppressing loss due to re-absorption of the second light.

[0171] (Appendix 7) the light guide portion is an air layer, the second light converted by the first wavelength conversion element and the third light emitted from the second light source travel through the air layer and are emitted from a region on the third surface side of the air layer. 6. A light source device according to any one of claims 1 to 5.

[0172] According to this configuration, the refractive index difference between the first wavelength conversion element and the light guide is larger than when the second light is incident on a light guide made of a translucent material, so the second light travels in a direction that forms a small angle with respect to the longitudinal direction of the first wavelength conversion element. Furthermore, since the region on the third surface side of the light guide is open to the external air layer and does not have a refractive index interface, the second light that reaches the region on the third surface side is emitted directly into the external space without reflection or refraction. This increases the extraction efficiency of the second light.

[0173] (Appendix 8) further comprising a first reflecting member and a second 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 first reflecting member is disposed in an area on the fourth surface side of the light guiding unit, The second reflecting member is disposed in an area on the fifth surface side of the light guiding section. 8. A light source device according to any one of claims 1 to 7.

[0174] This configuration can increase the efficiency of converting the first light into the second light by the first reflecting member and the second reflecting member, and can also reduce the loss of each light beam emitted from the fourth and fifth surfaces and absorbed by the housing.

[0175] (Appendix 9) The first wavelength conversion element is made of a transparent phosphor. 9. A light source device according to any one of claims 1 to 8.

[0176] According to this configuration, even when the first wavelength conversion element made of a transparent phosphor is used, the second light can be efficiently extracted to the outside from the region on the third surface side of the light guide portion.

[0177] (Appendix 10) The first wavelength conversion element is made of a phosphor having light scattering properties. 9. A light source device according to any one of claims 1 to 8.

[0178] According to this configuration, the propagation direction of the second light changes in various directions due to the scattering of light by the first wavelength conversion element, and the second light can be propagated inside the light guiding section and efficiently emitted from the third surface side, thereby reducing loss of the second light and further increasing the extraction efficiency of the second light.

[0179] (Appendix 11) a first light source that emits first light in a first wavelength band; a first wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band; a first optical layer disposed between the first light source and the first wavelength conversion element, the first optical layer transmitting the first light and reflecting the second light; a light guide portion that is disposed on the 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 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 second light source that emits fourth light in a fourth wavelength band different from the second wavelength band and the third wavelength band; Equipped with the first wavelength conversion element has a first surface onto which the first light is incident via the first optical layer, and a second surface and a third surface that intersect with the first surface and face in opposite directions to each other; the second light source is disposed in an area on the second surface side of the light guiding section, the first optical layer and the second optical layer reflect the fourth light emitted from the second light source in addition to the second light and the third light, a part of the second light converted by the first wavelength conversion element, the third light converted by the second wavelength conversion element, and the fourth light emitted from the second light source travels through the light guiding section and is emitted from a region on the third surface side of the light guiding section; Light source device.

[0180] According to the light source device having this configuration, the second light generated by the first wavelength conversion element, the third light generated by the second wavelength conversion element, and the fourth light emitted from the second light source travel through the light guide and are emitted from the region on the third surface side of the light guide. Therefore, compared to, for example, a conventional light source device in which all of the fluorescence propagates inside the wavelength conversion element, loss of the second light and the third light is reduced, and the utilization efficiency of the second light and the third light can be improved. Furthermore, the light source device having this configuration can efficiently emit illumination light in which the second light, the third light, and the fourth light are combined.

[0181] (Appendix 12) a third optical layer disposed between the first wavelength conversion element and the light guiding portion, the third optical layer transmitting the first light, the second light, and the third light and reflecting the fourth light; a fourth optical layer disposed between the second wavelength conversion element and the light guiding unit, the fourth optical layer transmitting the first light, the second light, and the third light and reflecting the fourth light; Furthermore, the fourth wavelength band of the fourth light is larger than the first wavelength band of the first light, the second wavelength band of the second light and the third wavelength band of the third light are larger than the fourth wavelength band of the fourth light; 12. The light source device according to claim 11.

[0182] According to this configuration, the fourth light is reflected by the third optical layer and the fourth optical layer, so that the fourth light can be effectively propagated inside the light-guiding unit. Furthermore, for example, by using yellow fluorescent light as the second light and the third light and blue light as the fourth light, the second light, the third light, and the fourth light can be combined to generate white illumination light.

[0183] (Appendix 13) the first wavelength conversion element and the second wavelength conversion element are made of a yellow phosphor having light scattering properties, the first light is a first blue light; the second light and the third light are yellow fluorescent light, the fourth light is a second blue 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 second blue light propagates through the light guiding unit while repeatedly being reflected by the third optical layer and the fourth optical layer, and is emitted from a region of the light guiding unit on the third surface side. 13. The light source device of claim 12.

[0184] According to 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 each wavelength conversion element, and the second light and the third light can be efficiently emitted from the region on the third surface side after propagating inside the light guide unit. Therefore, loss of the second light and the third light can be reduced, and the extraction efficiency of the second light and the third light can be further improved. Furthermore, white illumination light obtained by combining the yellow fluorescence generated by the first wavelength conversion element and the second wavelength conversion element and the second blue light emitted from the second light source can be efficiently extracted from the third surface side of the light guide unit.

[0185] (Appendix 14) a fifth optical layer disposed at least between the second light source and a region on the second surface side of the light guiding section, the fifth optical layer transmitting the fourth light and reflecting the second light and the third light; 14. A light source device according to any one of claims 11 to 13.

[0186] According to this configuration, the fifth optical layer reflects the second light and the third light and transmits the fourth light, thereby enabling the second light, the third light, and the fourth light to be efficiently emitted from the area on the third surface side of the light guide section.

[0187] (Appendix 15) 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, the third light, and the fourth 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 unit, the first wavelength conversion element, and the second wavelength conversion element. 15. A light source device according to any one of claims 11 to 14.

[0188] According to this configuration, the housing can protect the first optical layer, the second optical layer, the first wavelength conversion element, and the second wavelength conversion element, and the light propagating inside the light guide can be extracted as illumination light from the extraction port. In addition, since the etendue of the illumination light is reduced, loss of the illumination light in optical members arranged downstream of the light source device can be reduced.

[0189] (Appendix 16) a first light-transmitting member that transmits the first light, the second light, the third light, and the fourth light is disposed in the light guide portion; a part of the second light converted by the first wavelength conversion element, the third light converted by the second wavelength conversion element, and the fourth light emitted from the second light source travels inside the first light-transmitting member and is emitted from an end face of the first light-transmitting member on the third surface side; 16. A light source device according to any one of claims 11 to 15.

[0190] According to this configuration, since the first light-transmissive member is disposed in the light guiding section, the difference in refractive index between each wavelength conversion element and the light guiding section is smaller than in a configuration in which the light guiding section is constituted by an air layer, and therefore 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.

[0191] (Appendix 17) the light guide portion is an air layer, the second light converted by the first wavelength conversion element, the third light converted by the second wavelength conversion element, and the fourth light emitted from the second light source travel through the air layer and are emitted from a region on the third surface side of the air layer. 17. A light source device according to any one of claims 11 to 16.

[0192] With this configuration, the refractive index difference between each wavelength conversion element and the light guide is greater than when the second light and the third light enter a light guide made of a translucent material, 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, because the region on the third surface side of the light guide is open to the external air layer 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.

[0193] (Appendix 18) further comprising a first reflecting member and a second reflecting member that reflect the first light, the second light, the third light, and the fourth 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 first reflecting member is disposed in an area on the fourth surface side of the light guiding unit, The second reflecting member is disposed in an area on the fifth surface side of the light guiding section. 18. A light source device according to any one of claims 11 to 17.

[0194] With this configuration, the first and second reflecting members can increase the efficiency of converting the first light into the second light and the efficiency of converting 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.

[0195] (Appendix 19) The first wavelength conversion element and the second wavelength conversion element are made of a transparent phosphor. 19. A light source device according to any one of claims 11 to 18.

[0196] 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 area on the third surface side of the light guide section.

[0197] (Appendix 20) The first wavelength conversion element and the second wavelength conversion element are made of a phosphor having light scattering properties. 19. A light source device according to any one of claims 11 to 18.

[0198] With this configuration, the propagation directions of the second light and the third light are changed in various directions due to 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.

[0199] (Appendix 21) a light source device according to any one of Supplementary Note 1 to Supplementary Note 20; a light modulation device that modulates the light emitted from the light source device; a projection optical device that projects the light modulated by the light modulation device; A projector equipped with

[0200] 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]

[0201] 1...Projector, 4B, 4G, 4R...Light modulation device, 6...Projection optical device, 30A, 30B, 30C, 130, 130A, 130B, 130C...Light source device, 31...Housing, 31K...Outlet, 41, 41a, 41b...First light source, 42...Second light source, 51, 53...First wavelength conversion element, 52, 54...Second wavelength conversion element, 61, 161...First optical layer, 62, 162...Second optical optical layer, 63,163...third optical layer, 71,76,171,176...light-guiding section, 73...first light-transmissive member, 73a,73b...end surface, 77,177...air layer, 81...first reflecting member, 82...second reflecting member, 164...fourth optical layer, 165...fifth optical layer, LB...blue light, Y,Y0,Y1,Y2,Y3,Y4,Y5,Y01,Y02,Y03,Y04,Y05,Y06...fluorescence.

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 second light source that emits third light in a third wavelength band different from the second wavelength band; a light guiding section disposed between the first wavelength conversion element and the first optical layer, which guides the second light converted by the first wavelength conversion element and the third light emitted from the second light source; Equipped with the first wavelength conversion element has a first surface onto which the first light is incident via the first optical layer, and a second surface and a third surface that intersect with the first surface and face in opposite directions to each other; the second light source is disposed in a region on the second surface side of the light guiding section, the first optical layer reflects the third light emitted from the second light source in addition to the second light, the second light converted by the first wavelength conversion element and a portion of the third light emitted from the second light source travel through the light guiding unit and are emitted from a region on the third surface side of the light guiding unit. Light source device.

2. Further, a second optical layer is provided between the first wavelength conversion element and the light guiding portion, the third wavelength band of the third light is larger than the first wavelength band of the first light, the second wavelength band of the second light is larger than the third wavelength band of the third light; the second optical layer transmits the first light and the second light and reflects the third light; The light source device according to claim 1 .

3. the first wavelength conversion element is made of a yellow phosphor having light scattering properties, the first light is a first blue light; the second light is yellow fluorescent light, the third light is a second blue light, the fluorescent light propagates through the light guiding unit while being repeatedly scattered by the first wavelength conversion element and reflected by the first optical layer, and is emitted from a region of the light guiding unit on the third surface side, the second blue light propagates through the light guiding unit while repeatedly being reflected by the first optical layer and the second optical layer, and is emitted from a region of the light guiding unit on the third surface side. The light source device according to claim 2 .

4. a third optical layer disposed at least between the second light source and a region on the second surface side of the light guiding section, the third optical layer transmitting the third light and reflecting the second light; The light source device according to claim 1 .

5. Further, a housing is provided to accommodate the first optical layer and the first wavelength conversion element, the housing has an outlet through which the second light and the third light 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 unit and the first wavelength conversion element. The light source device according to claim 1 .

6. 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 a portion of the third light emitted from the second light source 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 .

7. the light guide portion is an air layer, the second light converted by the first wavelength conversion element and the third light emitted from the second light source 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 .

8. a first reflecting member and a second 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 first reflecting member is disposed in an area on a fourth surface side of the light guiding unit, The second 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 .

9. The first wavelength conversion element is made of a transparent phosphor.

3. The light source device according to claim 1.

10. The first wavelength conversion element is made of a phosphor having light scattering properties.

3. The light source device according to claim 1.

11. a first light source that emits first light in a first wavelength band; a first wavelength conversion element that converts the first light into second light in a second wavelength band different from the first wavelength band; a first optical layer disposed between the first light source and the first wavelength conversion element, the first optical layer transmitting the first light and reflecting the second light; a 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 second light source that emits fourth light in a fourth wavelength band different from the second wavelength band and the third wavelength band; Equipped with the first wavelength conversion element has a first surface onto which the first light is incident via the first optical layer, and a second surface and a third surface that intersect with the first surface and face in opposite directions to each other; the second light source is disposed in a region on the second surface side of the light guiding section, the first optical layer and the second optical layer reflect the fourth light emitted from the second light source in addition to the second light and the third light, a part of the second light converted by the first wavelength conversion element, the third light converted by the second wavelength conversion element, and the fourth light emitted from the second light source travels through the light guiding unit and is emitted from a region on the third surface side of the light guiding unit; Light source device.

12. a third optical layer disposed between the first wavelength conversion element and the light guiding unit, the third optical layer transmitting the first light, the second light, and the third light and reflecting the fourth light; a fourth optical layer disposed between the second wavelength conversion element and the light guiding unit, the fourth optical layer transmitting the first light, the second light, and the third light and reflecting the fourth light; Furthermore, the fourth wavelength band of the fourth light is larger than the first wavelength band of the first light, the second wavelength band of the second light and the third wavelength band of the third light are larger than the fourth wavelength band of the fourth light; The light source device according to claim 11.

13. the first wavelength conversion element and the second wavelength conversion element are made of a yellow phosphor having light scattering properties, the first light is a first blue light; the second light and the third light are yellow fluorescent light, the fourth light is a second blue 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 second blue light propagates through the light guiding unit while being repeatedly reflected by the third optical layer and the fourth optical layer, and is emitted from a region of the light guiding unit on the third surface side. The light source device according to claim 12.

14. a fifth optical layer disposed at least between the second light source and a region on the second surface side of the light guiding section, the fifth optical layer transmitting the fourth light and reflecting the second light and the third light; The light source device according to any one of claims 11 to 13.

15. 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, the third light, and the fourth 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 unit, the first wavelength conversion element, and the second wavelength conversion element. The light source device according to any one of claims 11 to 13.

16. a first light-transmitting member that transmits the first light, the second light, the third light, and the fourth light is disposed in the light guide portion; a part of the second light converted by the first wavelength conversion element, the third light converted by the second wavelength conversion element, and the fourth light emitted from the second light source travels inside the first light-transmitting member and is emitted from an end face of the first light-transmitting member on the third surface side; The light source device according to any one of claims 11 to 13.

17. the light guide portion is an air layer, the second light converted by the first wavelength conversion element, the third light converted by the second wavelength conversion element, and the fourth light emitted from the second light source 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 any one of claims 11 to 13.

18. a first reflecting member and a second reflecting member that reflect the first light, the second light, the third light, and the fourth 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 first reflecting member is disposed in an area on a fourth surface side of the light guiding unit, The second reflecting member is disposed in an area on the fifth surface side of the light guiding section. The light source device according to any one of claims 11 to 13.

19. The first wavelength conversion element and the second wavelength conversion element are made of a transparent phosphor.

13. The light source device according to claim 11 or 12.

20. The first wavelength conversion element and the second wavelength conversion element are made of a phosphor having light scattering properties.

13. The light source device according to claim 11 or 12.

21. The light source device according to any one of claims 1 to 3; 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.

22. The light source device according to any one of claims 11 to 13; 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