Light source device and projector

Abstract

To provide a light source device and a projector having high light utilization efficiency.SOLUTION: A light source device includes: a first light source that emits first light within a first wavelength band; a wavelength conversion element that converts the first light into second light within a second wavelength band different from the first wavelength band; a first light transmissive member that is disposed between the first light source and the wavelength conversion element and guides the second light into which the wavelength conversion element converts the first light; a first optical layer that is disposed between the first light source and the first light transmissive member, transmits the first light, and reflects the second light; and a first reflective member that reflects the first light and the second light. The wavelength conversion element has a first surface on which the first light is incident via the first optical layer and the first light transmissive member. The first light transmissive member has a second surface that faces the first surface, and a third surface and a fourth surface that intersect with the second surface and face mutually opposite sides. The third surface faces the first reflective member. The second light into which the wavelength conversion element converts the first light travels through an interior of the first light transmissive member and exits via the fourth surface.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] As a light source device for use in a projector, a light source device has been proposed that utilizes fluorescence emitted from a phosphor when the phosphor is irradiated with excitation light emitted from a light-emitting element. The following Patent Document 1 discloses a light source device that includes a flat wavelength conversion member containing a phosphor and a light-emitting diode (LED) that emits excitation light, in which the excitation light is incident on an entrance surface having a larger area among multiple surfaces of the wavelength conversion member, and the fluorescence is emitted from an exit surface having a smaller area of ​​the wavelength conversion member. [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, the generated fluorescence is totally reflected at the interface between the surface of the wavelength conversion member and the air layer, travels through the wavelength conversion member, and is emitted from the emission surface. However, there is a problem that the component of the fluorescence that is not totally reflected at the interface between the wavelength conversion member and the air layer becomes leakage light, which reduces the light utilization efficiency. [Means for solving the problem]

[0005] In order to solve the above problem, a light source device according to one embodiment of the present invention includes a first light source that emits a first light in a first wavelength band, a wavelength conversion element that converts the first light into a second light in a second wavelength band different from the first wavelength band, a first translucent member that is disposed between the first light source and the wavelength conversion element and guides the second light converted by the wavelength conversion element, a first optical layer that is disposed between the first light source and the first translucent member and transmits the first light and reflects the second light, and a first reflecting member that reflects the first light and the second light, wherein the wavelength conversion element has a first surface onto which the first light is incident via the first optical layer and the first translucent member, and the first translucent member has a second surface that faces the first surface, and a third surface and a fourth surface that intersect with the second surface and face in opposite directions to each other, the third surface faces the first reflecting member, and the second light converted by the wavelength conversion element travels inside the first translucent member and is emitted from the fourth surface.

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

[0007] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a projector according to a first embodiment. [Diagram 2] 3 is a side cross-sectional view showing a schematic configuration of a first illumination device. FIG. [Diagram 3] 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] 1A and 1B are diagrams illustrating the behavior of light in a light source device. [Diagram 5] 2 is a plan view of the light source device as viewed from the +X side toward the -X side. [Figure 6] FIG. 11 is a cross-sectional view showing a schematic configuration of a light source device according to a second embodiment. [Figure 7] FIG. 11 is a cross-sectional view showing a schematic configuration of a light source device according to a third embodiment. [Figure 8]FIG. 13 is a cross-sectional view showing a schematic configuration of a light source device according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, one embodiment of the present invention will be described. 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, the dimensions of the components may be shown on different scales in order to make the components easier to see.

[0009] FIG. 1 is a diagram showing a schematic configuration of a projector 1 according to the present 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 includes three light modulation devices corresponding to the respective colors of red light LR, green light LG, and blue light LB.

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

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

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

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

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

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

[0016] The configuration of the second illumination device 21 will be described below. The second illumination device 21 includes a light source unit 81, a condenser lens 82, a diffusion plate 83, a rod lens 86, and a relay lens 87. The light source unit 81 is composed of at least one semiconductor laser. The light source unit 81 emits blue light LB composed of laser light. Note that the light source unit 81 is not limited to a semiconductor laser, and may be composed of an LED that emits blue light.

[0017] The condenser lens 82 is composed of a convex lens. The condenser lens 82 causes the blue light LB emitted from the light source unit 81 to enter the diffusion plate 83 in a substantially condensed state. The diffusion plate 83 diffuses the blue light LB emitted from the condenser lens 82 with a predetermined diffusion degree, and generates blue light LB having a substantially uniform light distribution similar to that of the fluorescent light Y emitted from the first lighting device 20. As the diffusion plate 83, for example, ground glass made of optical glass is used.

[0018] The blue light LB diffused by the diffusion plate 83 is incident on the rod lens 86. The rod lens 86 has a prismatic shape extending along the optical axis AX2 direction of the second illumination device 21. The rod lens 86 has a light incident end surface 86a provided at one end and a light exit end surface 86b provided at the other end. The diffusion plate 83 is fixed to the light incident end surface 86a of the rod lens 86 via an optical adhesive (not shown). It is desirable to match the refractive index of the diffusion plate 83 and the refractive index of the rod lens 86 as closely as possible.

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

[0020] The shape of the light exit end surface 86b of the rod lens 86 is a rectangle that is approximately similar to the shape of the image forming area of ​​the light modulation device 4B. This allows the blue light LB exiting from the rod lens 86 to efficiently enter the image forming area of ​​the light modulation device 4B.

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

[0022] For example, a transmissive liquid crystal panel is used for each of the light modulation devices 4R, 4G, and 4B. A polarizing plate (not shown) is disposed on the entrance side and exit side of each of the liquid crystal panels. The polarizing plate transmits only linearly polarized light in a specific direction.

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

[0024] The light combining element 5 receives the image light emitted from the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, combines the image light corresponding to the red light LR, the green light LG, and the blue light LB, and emits the combined image light toward the projection optical device 6. The light combining element 5 may be, for example, a cross dichroic prism.

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

[0026] Next, the configuration of the first illumination device 20 will be described. Fig. 2 is a side cross-sectional view showing a schematic configuration of the first illumination device 20. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2.

[0027] As shown in FIG. 2, the first illumination device 20 includes a light source device 100, an integrator optical system 70, a polarization conversion element 63, and a superimposing optical system 64.

[0028] The light source device 100 includes a support member 30, a housing 31, a first light source 41, a wavelength conversion element 50, a first light-transmissive member 51, a first optical layer 52, a first reflecting member 53, and a pair of second reflecting members 54.

[0029] The support member 30 supports the wavelength conversion element 50. The support member 30 functions as a heat dissipation member that diffuses and releases heat from the wavelength conversion element 50. In other words, the wavelength conversion element 50 is connected to the support member 30 in a heat-transferable manner. For this reason, it is desirable that the support member 30 is made of a material that has a predetermined strength and high thermal conductivity. As a material for the support member 30, for example, a metal such as aluminum or stainless steel is used, and in particular, it is desirable to use an aluminum alloy such as 6061 series. According to this configuration, heat from the wavelength conversion element 50 is released via the support member 30, so that an increase in temperature of the wavelength conversion element 50 can be suppressed.

[0030] As shown in FIG. 3, the support member 30 has a base portion 32 and a support portion 33. The base portion 32 is a plate-shaped member forming the main body of the support member 30 and has a longitudinal direction in the X-axis direction. The support portion 33 is provided on a surface 32a located on the +Y side of the base portion 32. The support portion 33 has a groove 34 that supports the wavelength conversion element 50. The groove 34 extends in the X-axis direction along the longitudinal direction of the support portion 33 and accommodates the wavelength conversion element 50. The groove 34 in this embodiment has a depth that can accommodate the first light-transmitting member 51 and the first optical layer 52 together with the wavelength conversion element 50. The groove 34 has a bottom surface 34a along the XZ plane and a pair of inner wall surfaces 34b along the XY plane and spaced apart in the Z-axis direction. A pair of second reflecting members 54, which will be described later, are respectively arranged on the inner wall surfaces 34b of the groove 34.

[0031] The housing 31, together with the support member 30, is a member that constitutes the exterior of the light source device 100. The housing 31 has a generally box-like shape with one side open. The housing 31 has a top wall portion 31a, a first side wall portion 31c, a second side wall portion 31d, a third side wall portion 31e, a fourth side wall portion 31f, and an outlet 31k.

[0032] The top wall portion 31a is disposed along the XZ plane. The first side wall portion 31c and the second side wall portion 31d intersect with the X-axis along the longitudinal direction of the wavelength conversion element 50 and are located on opposite sides to each other in the X-axis direction. In this embodiment, the first side wall portion 31c is located on one side of the X-axis direction, that is, the -X side, and the second side wall portion 31d is located on the opposite side of the X-axis direction, that is, the +X side. The third side wall portion 31e and the fourth side wall portion 31f are located on opposite sides to each other in the Z-axis direction intersecting the longitudinal direction of the wavelength conversion element 50. In this embodiment, the third side wall portion 31e is located on one side of the Z-axis direction, that is, the +Z side, and the fourth side wall portion 31f is located on the opposite side of the Z-axis direction, that is, the -Z side.

[0033] In this embodiment, the first light source 41 is disposed on the top wall 31a of the housing 31. The first reflecting member 53 is disposed on the first side wall 31c of the housing 31. The outlet 31k is provided on the second side wall 31d of the housing 31. The outlet 31k is an opening for extracting light emitted from the first light-transmissive member 51 to the outside.

[0034] In this embodiment, the top wall portion 31a is connected to the first light source 41 so as to be capable of transferring heat. For this reason, it is preferable that the housing 31 is made of a material having a predetermined strength and high thermal conductivity. As with the support member 30, the material of the housing 31 is preferably a metal such as aluminum or stainless steel, and in particular, it is preferable that an aluminum alloy such as 6061 series is used.

[0035] The housing 31 is disposed so as to cover the support portion 33 of the support member 30 and to abut against the surface 32a of the base portion 32 of the support member 30. That is, the housing 31 covers the first optical layer 52, the first light-transmissive member 51, and the wavelength conversion element 50 supported in the groove 34. The housing 31 and the support member 30 are fixed to each other via a fixing member such as an adhesive or a screw.

[0036] In this manner, the light source device 100 of the present embodiment realizes a configuration in which the first optical layer 52, the first light-transmissive member 51, the wavelength conversion element 50, and the first light source 41 are housed inside the housing 31 and the support member 30. This makes it possible to suppress adhesion of foreign matter such as dust to the first optical layer 52, the first light-transmissive member 51, and the wavelength conversion element 50.

[0037] The first light source 41 has a plurality of first light emitting elements 41a and a substrate 41b. The plurality of first light emitting elements 41a are mounted on the substrate 41b. The number of the first light emitting elements 41a is not particularly limited, and the first light source 41 may have only one first light emitting element 41a.

[0038] The first light emitting element 41a emits an excitation light beam E1 in a first wavelength band. The first light emitting element 41a is composed of, for example, a light emitting diode (LED). Each light emitting element 41a faces the wavelength conversion element 50 and emits an excitation light beam E1 toward the wavelength conversion element 50. The first wavelength band is, for example, a wavelength band from blue to purple of 400 nm to 480 nm, and the peak wavelength is, for example, 445 nm. The multiple first light emitting elements 41a are arranged along the longitudinal direction of the wavelength conversion element 50. In this way, the first light source 41 of this embodiment emits excitation light E consisting of multiple blue excitation light beams E1.

[0039] The wavelength conversion element 50 has a long and narrow plate shape extending along the X-axis, and has six faces. The side of the wavelength conversion element 50 extending along the X-axis is longer than the side extending along the Y-axis and the side extending along the Z-axis. The X-axis corresponds to the longitudinal direction of the wavelength conversion element 50. The Y-axis corresponds to the shortest side of the wavelength conversion element 50. The length of the side along the Y-axis is shorter than the length of the side along the Z-axis. That is, the cross section of the wavelength conversion element 50 cut along a plane along the YZ plane is rectangular as shown in FIG. 3.

[0040] The wavelength conversion element 50 has a front surface 50a and a back surface 50b, a first end surface 50c and a second end surface 50d, and a first side surface 50e and a second side surface 50f. The front surface 50a and the back surface 50b intersect with the Y axis and are located on opposite sides of the Y axis. In this embodiment, the front surface 50a is a surface located on the +X side, which is one side of the Y axis direction along the Y axis. The back surface 50b is a surface located on the -Y side, which is the opposite direction of the Y axis direction, and abuts against the bottom surface 34a of the groove 34 of the support member 30. In other words, the back surface 50b of the wavelength conversion element 50 is a surface that is connected to the support member 30 in a heat-transferable manner. The front surface 50a is a surface into which the excitation light E is incident via the first optical layer 52 and the first light-transmitting member 51. In this embodiment, the front surface 50a of the wavelength conversion element 50 corresponds to the "first surface" in the claims. In addition, a reflective film may be formed on the rear surface 50b of the wavelength conversion element 50 to reflect the fluorescence Y emitted from the rear surface 50b back into the wavelength conversion element 50.

[0041] The first end face 50c and the second end face 50d are located on opposite sides to each other in the X-axis direction that intersects with the front surface 50a and the back surface 50b and follows the longitudinal direction of the wavelength conversion element 50. In this embodiment, the first end face 50c is located on one side of the X-axis direction, that is, the -X side, and the second end face 50d is located on the opposite side of the X-axis, that is, the +X side.

[0042] The first side surface 50e and the second side surface 50f intersect the front surface 50a and the back surface 50b and the first end surface 50c and the second end surface 50d, and are located opposite each other in the Z-axis direction. In this embodiment, the first side surface 50e is located on one side of the Z-axis direction, that is, the +Z side, and the second side surface 50f is located on the opposite side of the Z-axis direction, that is, the -Z side.

[0043] The wavelength conversion element 50 contains at least a yellow phosphor, and converts excitation light E having a first wavelength band emitted from each light emitting element 41a of the first light source 41 into yellow fluorescence Y having a second wavelength band different from the first wavelength band. In the wavelength conversion element 50, the excitation light E is incident on the surface 50a, and the fluorescence Y is emitted from the surface 50a into the first light-transmissive member 51. The excitation light E in this embodiment corresponds to the "first light" in the claims.

[0044] The wavelength conversion element 50 includes a ceramic phosphor made of a polycrystalline phosphor that converts the wavelength of the excitation light E into the fluorescence Y. The wavelength conversion element 50 includes a scattering body such as pores or filler. Therefore, the wavelength conversion element 50 of this embodiment is made of a phosphor having light scattering properties. The second wavelength band of the fluorescence Y is, for example, a yellow wavelength band of 490 to 750 nm. In other words, the fluorescence Y is yellow fluorescence containing a red light component and a green light component. The fluorescence Y of this embodiment corresponds to the "second light" in the claims.

[0045] The wavelength conversion element 50 may contain a single crystal phosphor instead of a polycrystalline phosphor. Alternatively, the wavelength conversion element 50 may be made of fluorescent glass. Alternatively, the wavelength conversion element 50 may be made of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin. The wavelength conversion element 50 made of such a material converts the excitation light E into fluorescence Y.

[0046] Specifically, the material of the wavelength conversion element 50 includes, for example, an yttrium-aluminum-garnet (YAG) phosphor. Taking YAG:Ce containing cerium (Ce) as an activator as an example, the material of the wavelength conversion element 50 may be a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and reacting them in a solid state, Y-Al-O amorphous particles obtained by a wet method such as a coprecipitation method or a sol-gel method, or YAG particles obtained by a gas phase method such as a spray drying method, a flame pyrolysis method, or a thermal plasma method.

[0047] The first light-transmissive member 51 is disposed between the first light source 41 and the wavelength conversion element 50, and guides the fluorescence Y converted by the wavelength conversion element 50. Specifically, the first light-transmissive member 51 is provided on a surface 50a of the wavelength conversion element 50.

[0048] Examples of the material for the first light-transmissive member 51 include borosilicate glass such as BK7, quartz, synthetic quartz, crystal, SiC, GaN, MgO, YAG, sapphire, and diamond. The first light-transmissive member 51 of the present embodiment is made of, for example, quartz.

[0049] The first light-transmissive member 51 has the same shape as the wavelength conversion element 50. Specifically, the first light-transmissive member 51 has a long and narrow plate shape extending along the X-axis and has six faces. The first light-transmissive member 51 has a longitudinal direction in the X-axis direction, and a cross section of the first light-transmissive member 51 cut along a plane along the YZ plane has a rectangular shape as shown in FIG.

[0050] The first light-transmissive member 51 has a front surface 51a and a back surface 51b, a first end surface 51c and 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 are located on opposite sides of the Y axis. In this embodiment, the front surface 51a is located on the +Y side, which is one side of the Y axis direction along the Y axis, and the back surface 51b is located on the -Y side, which is the opposite direction of the Y axis direction. The front surface 51a is a surface on which the excitation light E is incident via the first optical layer 52 described later. The back surface 51b is a surface facing the front surface 50a of the wavelength conversion element 50. In other words, the back surface 51b of the first light-transmissive member 51 corresponds to the "second surface" in the claims.

[0051] 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 light-transmissive member 51. In this embodiment, the first end face 51c is located on one side of the X-axis direction, that is, the -X side, and the second end face 51d is located on the opposite side of the X-axis direction, that is, the +X side. In other words, the first end face 51c and the second end face 51d correspond to the "third surface" and "fourth surface" in the claims.

[0052] The first side surface 51e and the second side surface 51f intersect with 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 of the Z-axis direction, that is, the +Z side, and the second side surface 51f is located on the opposite side of the Z-axis direction, that is, the -Z side. In other words, the first side surface 51e and the second side surface 51f correspond to the "fifth surface" and "sixth surface" in the claims.

[0053] The first optical layer 52 is disposed between the first light source 41 and the first light-transmissive member 51, and has the optical property of transmitting the excitation light E and reflecting the fluorescence Y. The first optical layer 52 of the present embodiment is provided on the surface 51a of the first light-transmissive member 51, and is made of, for example, a dielectric multilayer film.

[0054] 2, the first reflecting member 53 is located on the -X side in the X-axis direction of the first light-transmissive member 51 and the wavelength conversion element 50. The first reflecting member 53 is provided on the first side wall portion 31c of the support member 30 so as to face the first end face 51c of the first light-transmissive member 51 and the first end face 50c of the wavelength conversion element 50. The first reflecting member 53 may be provided directly on the first end face 51c of the first light-transmissive member 51 and the first end face 50c of the wavelength conversion element 50, instead of on the first side wall portion 31c.

[0055] The first reflecting member 53 reflects the fluorescence Y that guides the light inside the first light-transmissive member 51 and reaches the first end face 51c. The first reflecting member 53 also reflects the excitation light E that is scattered by the surface 50a of the wavelength conversion element 50, guides the light inside the first light-transmissive member 51, and reaches the first end face 51c. That is, the first reflecting member 53 reflects the fluorescence Y and the excitation light E. The first reflecting member 53 is composed of, for example, a metal film, a dielectric multilayer film, a scattering member made of barium sulfate, or the like.

[0056] As shown in FIG. 3, the pair of second reflecting members 54 are located on both sides of the first light-transmissive member 51 and the wavelength conversion element 50 in the Z-axis direction. One of the pair of second reflecting members 54 is provided on the inner wall surface 34b of the groove 34 provided in the support portion 33 so as to face the first side surface 50e of the wavelength conversion element 50 and the first side surface 51e of the first light-transmissive member 51. The other of the pair of second reflecting members 54 is provided on the inner wall surface 34b of the groove 34 provided in the support portion 33 so as to face the second side surface 50f of the wavelength conversion element 50 and the second side surface 51f of the first light-transmissive member 51. The second reflecting member 54 may be provided directly on the wavelength conversion element 50 and the first light-transmissive member 51 side, instead of on the inner wall surface 34b of the groove 34.

[0057] The second reflecting member 54 reflects the excitation light E that is scattered by the surface 50a of the wavelength conversion element 50, enters the first light-transmissive member 51, and reaches the first side surface 51e or the second side surface 51f, and causes the light E to enter the wavelength conversion element 50. This can increase the conversion efficiency of the fluorescence Y by the excitation light E. The second reflecting member 54 reflects the fluorescence Y that reaches the first side surface 51e or the second side surface 51f of the first light-transmissive member 51. The second reflecting member 54 reflects the fluorescence Y emitted from the first side surface 50e or the second side surface 50f of the wavelength conversion element 50 toward the wavelength conversion element 50 or the first light-transmissive member 51. The fluorescence Y returned to the wavelength conversion element 50 is scattered inside and emitted to the first light-transmissive member 51. That is, the second reflecting member 54 reflects the fluorescence Y and the excitation light E. The second reflecting member 54 is composed of, for example, a metal film, a dielectric multilayer film, a scattering member, or the like.

[0058] Next, the behavior of light in the light source device 100 of this embodiment will be described. FIG. 4 is a diagram illustrating the behavior of light in the light source device 100. As shown in FIG. 4, in the light source device 100 of this embodiment, the excitation light E emitted from the first light source 41 passes through the first optical layer 52 and the first light-transmissive member 51 and enters the wavelength conversion element 50. Note that a part of the excitation light E is backscattered on the surface of the wavelength conversion element 50 and returns to the first light source 41 side, but is reflected by the first optical layer 52 and the first light-transmissive member 51 and enters the wavelength conversion element 50.

[0059] When the excitation light E is incident on the wavelength conversion element 50, the phosphor contained inside the wavelength conversion element 50 is excited, and the fluorescence Y is emitted from an arbitrary light-emitting point. At this time, the excitation light E incident on the phosphor is diffused and propagates to an area wider than the incident area, and the width of the emission area of ​​the fluorescence Y increases, so-called bleeding of the fluorescence Y occurs.

[0060] The fluorescence Y emitted from the surface 50a of the wavelength conversion element 50 enters the first light-transmissive member 51, and is reflected by the first optical layer 52 provided on the surface 50a of the first light-transmissive member 51, and is emitted from the second end face 51d. That is, in the light source device 100 of this embodiment, the fluorescence Y propagates inside the first light-transmissive member 51 while being repeatedly scattered by the wavelength conversion element 50 and reflected by the first optical layer 52, and is emitted from the second end face 51d. In this manner, the light source device 100 can emit the fluorescence Y generated by the wavelength conversion element 50 from the outlet 31k of the housing 31 to the outside.

[0061] A portion of the fluorescence Y1 emitted in various directions due to bleeding is emitted into the first light-transmissive member 51 toward the first end face 51c opposite the second end face 51d, but is reflected by the first optical layer 52 and enters the wavelength conversion element 50 again. The fluorescence Y1 incident on the wavelength conversion element 50 is scattered and converted into various angular components. A portion of the fluorescence Y1 converted into various angular components is reflected by the first optical layer 52 provided on the surface 50a of the first light-transmissive member 51, and is emitted from the second end face 51d.

[0062] Moreover, the fluorescence Y that is reflected between the first optical layer 52 and the wavelength conversion element 50, travels inside the first light-transmissive member 51, and reaches the first end face 51c, is reflected by the first reflecting member 53 toward the second end face 51d, enters the wavelength conversion element 50, and is scattered by the wavelength conversion element 50, and eventually exits from the second end face 51d. Moreover, the excitation light E that is scattered by the surface 50a of the wavelength conversion element 50, travels inside the first light-transmissive member 51, and enters the first end face 51c, is reflected by the first reflecting member 53, enters the wavelength conversion element 50, and is used for conversion of the fluorescence Y in the wavelength conversion element 50.

[0063] In the light source device 100 of this embodiment, most of the fluorescence Y is emitted from the second end face 51d of the first translucent member 51, and very little fluorescence Y is emitted from the second end face 50d of the wavelength conversion element 50, with only a small amount being emitted from the vicinity of the surface 50a of the second end face 50d.

[0064] In the light source device 100 of this embodiment, the fluorescence Y converted by the wavelength conversion element 50 travels inside the first light-transmissive member 51 and is emitted from the second end surface 51d. Fig. 5 is a plan view of the light source device 100 viewed from the +X side toward the -X side. That is, Fig. 5 is a plan view of the light source device 100 viewed in the X-axis direction along the normal direction of the second end surface 51d of the first light-transmissive member 51. Hereinafter, the plan view in the X-axis direction with reference to Fig. 5 will be simply referred to as a planar view.

[0065] As shown in Fig. 5, the fluorescence Y emitted from the second end surface 51d of the first light-transmissive member 51 is extracted to the outside through an extraction port 31k provided in the second side wall portion 31d of the housing 31. In a planar view as shown in Fig. 5, the extraction port 31k overlaps the first light-transmissive member 51 and the wavelength conversion element 50. Specifically, the extraction port 31k has a size that exposes the entire second end surface 51d of the first light-transmissive member 51 and the vicinity of the surface 50a of the second end surface 50d of the wavelength conversion element 50. In other words, the extraction port 31k overlaps the entire second end surface 51d of the first light-transmissive member 51 and a part of the second end surface 50d of the wavelength conversion element 50 in a planar view, and has a minimum size corresponding to the light emission region of the fluorescence Y.

[0066] In this way, the light source device 100 of this embodiment can extract the fluorescence Y emitted from the second end face 51d of the first light-transmissive member 51 and the second end face 50d of the wavelength conversion element 50 to the outside via the minimum extraction port 31k. Therefore, the light source device 100 of this embodiment can reduce the etendue of the fluorescence Y, thereby reducing the loss of light in optical members such as the integrator optical system 70 arranged in the subsequent stage. As a result, the utilization efficiency of the fluorescence Y of the light source device 100 can be improved.

[0067] In the present embodiment, the first light-transmissive member 51 and the wavelength conversion element 50 are fixed by a light-transmissive optical adhesive. Since no air layer is interposed between the first light-transmissive member 51 and the wavelength conversion element 50, it is possible to suppress reflection of light at the interface between the first light-transmissive member 51 and the wavelength conversion element 50. The optical adhesive transmits the excitation light E that has passed through the first light-transmissive member 51 to efficiently enter the wavelength conversion element 50, and transmits the fluorescence Y emitted from the wavelength conversion element 50 to efficiently enter the first light-transmissive member 51.

[0068] In this embodiment, the refractive index of the first light-transmissive member 51 (1.4: quartz) is smaller than the refractive index of the wavelength conversion element 50 (YAG: 1.7). In addition to quartz, the material of the first light-transmissive member 51 that satisfies this relationship is, for example, borosilicate glass such as BK7, synthetic quartz, and quartz. According to this configuration, the fluorescence Y is refracted when entering the first light-transmissive member 51 from the wavelength conversion element 50, so that the angle between the fluorescence Y and the X-axis along the long axis of the first light-transmissive member 51 becomes small. In other words, the fluorescence Y propagating through the first light-transmissive member 51 is incident at a small angle on the second end surface 51d that is perpendicular to the X-axis. Therefore, the first light-transmissive member 51 can efficiently extract the fluorescence Y from the second end surface 51d.

[0069] The first light-transmissive member 51 may be made of a material having a thermal conductivity greater than that of the wavelength conversion element 50. Examples of materials for the first light-transmissive member 51 that satisfy this relationship include SiC, GaN, MgO, YAG, sapphire, and diamond. With this configuration, heat from the wavelength conversion element 50 is efficiently transferred to the first light-transmissive member 51, so that a rise in temperature of the wavelength conversion element 50 can be suppressed. This makes it possible to suppress a decrease in luminous efficiency due to a rise in temperature of the wavelength conversion element 50.

[0070] As described above, the light source device 100 of the present embodiment includes the first light source 41 that emits excitation light E in a blue wavelength band, the wavelength conversion element 50 that converts the excitation light E into fluorescence Y in a yellow wavelength band different from the blue wavelength band, the first translucent member 51 that is disposed between the first light source 41 and the wavelength conversion element 50 and guides the fluorescence Y converted by the wavelength conversion element 50, the first optical layer 52 that is disposed between the first light source 41 and the first translucent member 51 and transmits the excitation light E and reflects the fluorescence Y, and the first reflecting member 53 that reflects the excitation light E and the fluorescence Y. The wavelength conversion element 50 has a surface 50a on which the excitation light E is incident via the first optical layer 52 and the first translucent member 51. The first translucent member 51 has a back surface 51b that faces the front surface 50a, and a first end surface 51c and a second end surface 51d that intersect the back surface 51b and face opposite each other. The first end surface 51c faces the first reflecting member 53, and the fluorescence Y converted by the wavelength conversion element 50 travels inside the first light-transmissive member 51 and is emitted from the second end surface 51d.

[0071] According to the light source device 100 of the present embodiment, the fluorescence Y reflected by the first optical layer 52 can be scattered in the wavelength conversion element 50, thereby causing the fluorescence Y to propagate inside the first light-transmissive member 51 with its angular distribution changed. For this reason, the fluorescence Y can be incident on the second end face 51d of the first light-transmissive member 51 at an angle smaller than the critical angle. Therefore, according to the light source device 100 of this embodiment, a configuration can be realized in which the fluorescence Y can be extracted more efficiently than in the case where the fluorescence Y is propagated within the first light-transmissive member 51 by total reflection.

[0072] According to the projector 1 of the present embodiment, since it is provided with the first illumination device 20 including the light source device 100 that efficiently extracts the fluorescent light Y, it has excellent light utilization efficiency.

[0073] Second embodiment Next, the configuration of the projector of the second embodiment will be described. The difference between this embodiment and the first embodiment is the configuration of the light source device. Therefore, the configuration of the light source device will be mainly described below. Note that the same reference numerals are used to designate components common to the first embodiment, and descriptions thereof will be omitted.

[0074] FIG. 6 is a cross-sectional view showing a schematic configuration of a light source device 101 of the present embodiment. As shown in FIG. 6, the light source device 101 of this embodiment includes a housing 131, a first light source 41, a second light source 42, a wavelength conversion element 50, a first light-transmissive member 51, a second light-transmissive member 151, a first optical layer 52, a second optical layer 152, a first reflecting member 153, and a pair of second reflecting members.

[0075] The housing 131 constitutes the exterior of the light source device 100. The housing 131 accommodates the first light source 41, the second light source 42, the wavelength conversion element 50, the first light-transmissive member 51, and the second light-transmissive member therein by covering them. The housing 131 has a box-like shape and has a top wall portion 131a, a bottom wall portion 131b, a first side wall portion 131c, a second side wall portion 131d, a third side wall portion, a fourth side wall portion, and an outlet 131k.

[0076] The top wall 131a is disposed along the XZ plane. The bottom wall 131b is disposed to face the top wall 131a. The first side wall 131c is located on the -X side in the X-axis direction, and the second side wall 131d is located on the +X side in the opposite direction in the X-axis direction. The third side wall portion and the fourth side wall portion, not shown, are located on opposite sides to each other in the Z-axis direction intersecting the longitudinal direction of the wavelength conversion element 50. The third side wall portion is located on one side of the Z-axis direction, that is, the +Z side, and the fourth side wall portion is located on the opposite side of the Z-axis direction, that is, the -Z side.

[0077] In this embodiment, the first light source 41 is disposed on a top wall portion 131a of the housing 131 so as to be capable of conducting heat therethrough, and the second light source 42 is disposed on a bottom wall portion 131b of the housing 131 so as to be capable of conducting heat therethrough. The outlet 131k is provided in a second side wall portion 131d of the housing 131.

[0078] In this embodiment, the outlet 131k holds the first optical layer 52, the first light-transmissive member 51, the wavelength conversion element 50, the second light-transmissive member 151, and the second optical layer 152. In this embodiment, when the light source device 101 is viewed in a plan view in the X-axis direction along the normal direction of the second end face 51d of the first light-transmissive member 51, the outlet 131k overlaps the first light-transmissive member 51, the wavelength conversion element 50, and the second light-transmissive member 151. Specifically, the outlet 131k has a size that exposes the second end face 51d of the first light-transmissive member 51, the second end face 50d of the wavelength conversion element 50, and the second end face 151d of the second light-transmissive member 151.

[0079] In addition, the open end of the extraction port 131k is flush with the second end face 51d of the first light-transmissive member 51, the second end face 50d of the wavelength conversion element 50, and the second end face 151d of the second light-transmissive member 151 in the X-axis direction.

[0080] The second light source 42 is disposed on the -Y side of the wavelength conversion element 50, which is the opposite side to the first light source 41, and emits excitation light E. The second light source 42 has a configuration similar to that of the first light source 41. Therefore, the second light source 42 has a plurality of second light-emitting elements 42a that emit excitation light rays in the first wavelength band, and a substrate 42b.

[0081] The second light-transmissive member 151 is disposed between the second light source 42 and the wavelength conversion element 50, and guides the fluorescence Y converted by the wavelength conversion element 50. Specifically, the second light-transmissive member 151 is provided on the back surface 50b of the wavelength conversion element 50. The second light-transmissive member 151 has a similar configuration to the first light-transmissive member 51.

[0082] Therefore, the second light-transmissive member 151 has a long and narrow plate shape extending along the X-axis and has six faces. The second light-transmissive member 151 has a front surface 151a, a back surface 151b, a first end surface 151c, a second end surface 151d, and a first side surface and a second side surface.

[0083] The second optical layer 152 is disposed between the second light source 42 and the second light-transmissive member 151, and has the optical property of transmitting the excitation light E and reflecting the fluorescence Y. The second optical layer 152 in this embodiment is provided on a surface 151a (described later) of the second light-transmissive member 151, and is made of, for example, a dielectric multilayer film.

[0084] In this embodiment, the excitation light E emitted from the second light source 42 is incident on the back surface 50b of the wavelength conversion element 50 via the second optical layer 152 and the second light-transmissive member 151. That is, the back surface 50b of the wavelength conversion element 50 corresponds to the "seventh surface" in the claims.

[0085] In the second light-transmissive member 151 of this embodiment, the front surface 151a is located on the -Y side, which is one side of the Y-axis direction along the Y-axis, and the back surface 151b is located on the +Y side, which is the opposite direction of the Y-axis direction. The front surface 151a is a surface onto which the excitation light E is incident via the second optical layer 152. The back surface 151b is a surface opposed to the back surface 50b of the wavelength conversion element 50. In other words, the back surface 151b of the second light-transmissive member 151 corresponds to the "eighth surface" in the claims.

[0086] In this embodiment, the first end face 151c and the second end face 151d intersect the front face 151a and the back face 151b and face opposite each other in the X-axis direction along the longitudinal direction of the second light-transmissive member 151. In this embodiment, the first end face 151c is located on one side of the X-axis direction, that is, the -X side, and the second end face 151d is located on the opposite side of the X-axis direction, that is, the +X side. In other words, the first end face 151c and the second end face 151d correspond to the "ninth surface" and "tenth surface" in the claims.

[0087] The first reflecting member 53 is located on the -X side in the X-axis direction of the first light-transmissive member 51, the second light-transmissive member 151, and the wavelength conversion element 50. The first reflecting member 53 is provided on the first side wall portion 131c of the housing 131 so as to face the first end face 51c of the first light-transmissive member 51, the first end face 151c of the second light-transmissive member 151, and the first end face 50c of the wavelength conversion element 50.

[0088] Although not shown in the drawings, in this embodiment, a pair of second reflecting members are located on both sides of the first light-transmissive member 51, the second light-transmissive member 151, and the wavelength conversion element 50 in the Z-axis direction. One of the second reflecting members is provided on a third side wall of the housing 131 so as to face the first side surface 50e of the wavelength conversion element 50, the first side surface 51e of the first light-transmissive member 51, and the first side surface of the second light-transmissive member 151. The other second reflecting member is provided on a fourth side wall of the housing 131 so as to face the second side surface 50f of the wavelength conversion element 50, the second side surface 51f of the first light-transmissive member 51, and the second side surface of the second light-transmissive member 151.

[0089] Next, the behavior of light in the light source device 101 of this embodiment will be described. Since the fluorescence Y generated by the excitation light E of the first light source 41 and the fluorescence Y generated by the excitation light E of the second light source 42 exhibit the same behavior, the excitation light E emitted from the first light source 41 will be described as an example below.

[0090] In the light source device 101 of this embodiment, the fluorescence Y2 emitted from the wavelength conversion element 50 enters the first translucent member 51, and is reflected by the first optical layer 52 provided on the surface 50a of the first translucent member 51, thereby being emitted from the second end face 51d.

[0091] The fluorescence Y3 emitted in the normal direction from the surface 50a of the wavelength conversion element 50 passes through the first light-transmissive member 51 and is reflected by the first optical layer 52 to return to the wavelength conversion element 50. The fluorescence Y3 is scattered by the wavelength conversion element 50 and enters the first light-transmissive member 51 in an angle-converted state, and is reflected by the first optical layer 52 to be emitted from the second end face 51d.

[0092] A portion of the fluorescence Y4 passes through the second light-transmissive member 151 and is reflected by the second optical layer 152 to be emitted from the second end face 151d. The fluorescence Y that is reflected between the second optical layer 152 and the wavelength conversion element 50 to travel inside the second light-transmissive member 151 and reaches the first end face 151c is reflected by the first reflecting member 53 toward the second end face 151d and is incident on the wavelength conversion element 50, whereby it is angle-converted, and eventually is emitted from the second end face 151d.

[0093] Also in this embodiment, the fluorescence Y that is reflected between the first optical layer 52 and the wavelength conversion element 50, travels inside the first light-transmissive member 51, and reaches the first end face 51c, is reflected by the first reflecting member 53 toward the second end face 51d, enters the wavelength conversion element 50, and is scattered by the wavelength conversion element 50, and eventually exits from the second end face 51d. Moreover, the excitation light E that is scattered by the surface 50a of the wavelength conversion element 50, travels inside the first light-transmissive member 51, and enters the first end face 51c is reflected by the first reflecting member 53, enters the wavelength conversion element 50, and is used for conversion of the fluorescence Y in the wavelength conversion element 50.

[0094] According to the light source device 101 of this embodiment, the amount of excitation light E incident can be increased by making the excitation light E incident from both the front surface 50a and the back surface 50b of the wavelength conversion element 50. Here, as the length of the wavelength conversion element 50 in the X-axis direction increases, it becomes more difficult to extract the fluorescence Y generated on the opposite side to the extraction port. For this reason, if the incidence area of ​​the excitation light E is expanded by increasing the length of the wavelength conversion element 50 in the X-axis direction, there is a risk that the fluorescence Y cannot be efficiently extracted. In contrast, in the light source device 101 of this embodiment, the amount of incident light of the excitation light E can be increased without increasing the length of the wavelength conversion element 50 in the X-axis direction, thereby increasing the fluorescence conversion efficiency and efficiently extracting the generated fluorescence.

[0095] In the light source device 100 of the first embodiment, the fluorescence Y is returned into the wavelength conversion element 50 by a reflective film formed on the back surface 50b of the wavelength conversion element 50. However, since it is difficult to obtain sufficient film performance from the reflective film formed on the back surface 50b having unevenness, light absorption is likely to occur.

[0096] In contrast, in the case of the present embodiment, the fluorescence Y emitted from the rear surface 50b of the wavelength conversion element 50 is reflected between the second optical layer 152 made of a dielectric multilayer film and the wavelength conversion element 50 and propagates through the second light-transmissive member 151, so that the fluorescence Y can be efficiently extracted. In addition, since the second optical layer 152 is formed on the front surface 151a of the second light-transmissive member 151 made of a smooth surface, the film performance is high and the fluorescence Y can be efficiently reflected.

[0097] Third embodiment Next, the configuration of the projector of the third embodiment will be described. The difference between this embodiment and the second embodiment is the configuration of the light source device. Therefore, the configuration of the light source device will be mainly described below. Note that the same reference numerals are used to designate components common to the first embodiment, and descriptions thereof will be omitted.

[0098] FIG. 7 is a cross-sectional view showing a schematic configuration of a light source device 102 of the present embodiment. The light source device 102 of this embodiment is different from the light source device 101 of the second embodiment in the configuration of the wavelength conversion element, but is otherwise common. Therefore, the following mainly describes the behavior of light due to differences in the wavelength conversion element.

[0099] As shown in FIG. 7, the light source device 102 of this embodiment includes a housing 131, a first light source 41, a second light source 42, a wavelength conversion element 150, a first light-transmissive member 51, a second light-transmissive member 151, a first optical layer 52, a second optical layer 152, a first reflecting member 153, and a pair of second reflecting members.

[0100] The wavelength conversion element 150 of this embodiment is composed of a transparent phosphor. Here, the transparent phosphor refers to a phosphor having a total light transmittance of 80% or more for fluorescence, for example. As described above, the transparent phosphor may be a transparent single crystal or polycrystal having a total light transmittance of 80% or more, for example, a YAG ceramic phosphor in which a plurality of YAG phosphor particles are sintered. The wavelength conversion element 150 converts the wavelength of the excitation light E incident from the first light source 41 and the second light source 42 to generate fluorescence Y.

[0101] Similar to the wavelength conversion element 50, the wavelength conversion element 150 of this embodiment has a front surface 150a, a back surface 150b, a first end face 150c, a second end face 150d, and first and second side faces (not shown).

[0102] Next, the behavior of light in the light source device 102 of this embodiment will be described. In the following, the excitation light E emitted from the first light source 41 will be described as an example. In the light source device 102 of this embodiment, the fluorescence Y5 emitted from the wavelength conversion element 50 propagates within the wavelength conversion element 150 by being totally reflected at the interface between the wavelength conversion element 150 and the first translucent member 51 or the second translucent member 151, and is emitted from the second end face 150d of the wavelength conversion element 150.

[0103] The fluorescence Y6 incident on the first light-transmissive member 51 at an angle larger than the critical angle is reflected by the first optical layer 52 and returns to the wavelength conversion element 150, passes through the wavelength conversion element 150, enters the second light-transmissive member 151, and is emitted from the second end face 151d of the second light-transmissive member 151. The fluorescence Y7 incident on the second light-transmissive member 151 is reflected by the second optical layer 152 and is emitted from the second end face 151d of the second light-transmissive member 151. A part of the fluorescence passes through the wavelength conversion element 50 from the second light-transmissive member 151, propagates through the first light-transmissive member 51, and is emitted from the second end face 51d.

[0104] The refractive indexes of the first light-transmissive member 51 and the second light-transmissive member 151 are closer to the refractive index of air than the refractive index of the wavelength conversion element 150. In the light source device 102 of the present embodiment, the second end face 51d of the first light-transmissive member 51 and the second end face 151d of the second light-transmissive member 151 emit a greater amount of fluorescence Y than the second end face 151d of the wavelength conversion element 150.

[0105] A portion of the fluorescence Y8 passes through the first light-transmissive member 51, is reflected by the first optical layer 52, and is incident on the second end face 150d of the wavelength conversion element 150. The fluorescence Y8 is totally reflected by the second end face 150d and is incident on the second light-transmissive member 151, is reflected by the second optical layer 152, and is again incident on the wavelength conversion element 150. The fluorescence Y8 that has returned to the wavelength conversion element 150 is scattered by the wavelength conversion element 150 and is angle-converted, and eventually exits from the second end face 51d of the first light-transmissive member 51 or the second end face 151d of the second light-transmissive member 151.

[0106] According to the light source device 102 of the present embodiment, even when using a wavelength conversion element 150 made of a transparent phosphor, it is possible to efficiently extract the generated fluorescence Y while improving the fluorescence conversion efficiency by increasing the amount of incident excitation light E without increasing the length of the wavelength conversion element 150 in the X-axis direction, as in the light source device 101 of the second embodiment.

[0107] (Fourth embodiment) Next, the configuration of the projector of the fourth embodiment will be described. The difference between this embodiment and the first embodiment is the configuration of the light source device. Therefore, the configuration of the light source device will be mainly described below. Note that the same reference numerals are used to designate components common to the first embodiment, and descriptions thereof will be omitted.

[0108] FIG. 8 is a cross-sectional view showing a schematic configuration of a light source device 103 of the present embodiment. As shown in FIG. 8, the light source device 103 of this embodiment includes a support member 30, a housing 31, a first light source 141, a wavelength conversion element 250, a first light-transmissive member 51, a first optical layer 252, a first reflecting member 53, and a pair of second reflecting members.

[0109] The first light source 141 of the present embodiment includes a plurality of first light emitting elements 141a and a substrate 141b. The plurality of first light emitting elements 141a are mounted on the substrate 141b. The number of the first light emitting elements 141a is not particularly limited, and the first light source 141 may include only one first light emitting element 141a.

[0110] The first light emitting element 141a of this embodiment emits an excitation light beam in a first wavelength band. The first light emitting element 141a is composed of, for example, a light emitting diode (LED). Each light emitting element 141a faces the wavelength conversion element 250 and emits an excitation light beam toward the wavelength conversion element 250. The first wavelength band is, for example, a wavelength band in the ultraviolet range of 100 nm to 400 nm, and has a peak wavelength of 380 nm. The multiple first light emitting elements 141a are arranged along the longitudinal direction of the wavelength conversion element 250. In this way, the first light source 141 of this embodiment emits ultraviolet light Ur consisting of multiple excitation light beams.

[0111] The wavelength conversion element 250 of this embodiment has a long and narrow plate shape extending along the X-axis, similar to the wavelength conversion element 50 of the first embodiment, and has six faces. The wavelength conversion element 250 of this embodiment is made of a blue phosphor that converts the ultraviolet light Ur emitted from the first light source 141 into blue fluorescence BY having a second wavelength band different from the first wavelength band, for example, a blue wavelength band of 450 to 495 nm. 10 O 17 The ultraviolet light Ur in this embodiment corresponds to the "first light" in the claims, and the fluorescent light BY corresponds to the "second light" in the claims.

[0112] The first optical layer 252 is disposed between the first light source 141 and the first light-transmissive member 51, and has the optical property of transmitting ultraviolet light Ur and reflecting fluorescent light BY. The other configuration is similar to that of the light source device 100 of the first embodiment, and therefore a description thereof will be omitted.

[0113] In the light source device 103 of this embodiment, the fluorescent light BY propagates through the first light-transmissive member 51 while being repeatedly scattered by the wavelength conversion element 250 and reflected by the first optical layer 252, and is emitted from the second end surface 51d. In this manner, the light source device 103 can emit the fluorescent light BY generated by the wavelength conversion element 250 to the outside through the outlet 31k of the housing 31.

[0114] In the light source device 103 of the present embodiment, the fluorescence BY reflected by the first optical layer 252 can also be scattered in the wavelength conversion element 250, and can be propagated inside the first light-transmissive member 51 with its angular distribution changed. For this reason, the fluorescence BY can be incident on the second end face 51d of the first light-transmissive member 51 at an angle smaller than the critical angle. Therefore, according to the light source device 103 of the present embodiment, a configuration can be realized in which the fluorescence BY can be extracted more efficiently than in the case where the fluorescence BY is propagated within the first light-transmissive member 51 by total reflection.

[0115] Furthermore, since the light source device 103 of this embodiment is equipped with the first light source 41 that uses the first light-emitting element 141a consisting of an LED, it generates less heat than a light source device that uses multiple blue semiconductor lasers, and the cooling device configuration can be made more compact. Furthermore, when using a conventional laser light source, a light synthesis optical system using mirrors, prisms, etc. is required to increase the amount of blue light, which causes a problem that the device configuration tends to become large. In contrast, the light source device 103 of this embodiment has the advantage that even when increasing the amount of blue light, it is possible to increase the length of the wavelength conversion element 250 and increase the number of first light emitting elements 141a, and therefore the device configuration can be prevented from becoming large.

[0116] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. In addition, one aspect of the present invention can be a configuration in which the characteristic portions of the above-described embodiments are appropriately combined. In addition, the specific description of the shape, number, arrangement, material, etc. of each component of the light source device and the projector is not limited to the above embodiment and can be changed as appropriate. In addition, in the above embodiment, an example in which the light source device of the present invention is mounted on a projector using a liquid crystal panel is shown, but this is not limited to this. The light source device of the present invention may be applied to a projector using a digital micromirror device as a light modulation device. In addition, the projector does not need to have multiple light modulation devices, and may have only one light modulation device. Furthermore, the light source device of the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

[0117] Summary of the Disclosure The following is a summary of this disclosure. (Appendix 1) a first light source that emits a first light in a first wavelength band; a wavelength conversion element that converts the first light into a second light in a second wavelength band different from the first wavelength band; a first light-transmissive member disposed between the first light source and the wavelength conversion element and configured to guide the second light converted by the wavelength conversion element; a first optical layer disposed between the first light source and the first light-transmissive member, the first optical layer transmitting the first light and reflecting the second light; a first reflecting member that reflects the first light and the second light; Equipped with the wavelength conversion element has a first surface to which the first light is incident via the first optical layer and the first light-transmitting member, the first light-transmissive member has a second surface opposing the first surface, and a third surface and a fourth surface intersecting the second surface and facing in opposite directions; the third surface faces the first reflecting member, the second light converted by the wavelength conversion element travels inside the first light-transmissive member and is emitted from the fourth surface. A light source device characterized by:

[0118] According to the light source device having the configuration of Supplementary Note 1, the second light reflected by the first optical layer can be scattered in the wavelength conversion element to change the angular distribution and propagate into the first translucent member. Therefore, the second light can be incident on the fourth surface of the first translucent member at an angle smaller than the critical angle. Therefore, according to the light source device having this configuration, the second light can be extracted more efficiently than when the second light is propagated through the first translucent member by total reflection.

[0119] (Appendix 2) The refractive index of the first light-transmissive member is smaller than the refractive index of the wavelength conversion element. 2. A light source device according to claim 1.

[0120] According to the configuration of Supplementary Note 2, the second light is refracted when entering the first translucent member from the wavelength conversion element, and the angle it forms with the major axis of the first translucent member becomes small. In other words, the second light propagating through the first translucent member is incident at a small angle with respect to the fourth surface perpendicular to the major axis. Therefore, the first translucent member can efficiently extract the second light from the fourth surface.

[0121] (Appendix 3) The thermal conductivity of the first light-transmissive member is greater than the thermal conductivity of the wavelength conversion element. 3. A light source device according to claim 1 or 2.

[0122] According to the configuration of Supplementary Note 3, since the heat of the wavelength conversion element is efficiently transferred to the first light-transmissive member, it is possible to suppress a temperature rise of the wavelength conversion element, thereby suppressing a decrease in the luminous efficiency caused by a temperature rise of the wavelength conversion element.

[0123] (Appendix 4) The first light-transmissive member and the wavelength conversion element are fixed with a light-transmissive adhesive. 4. The light source device according to claim 1,

[0124] According to the configuration of Appendix 4, the optical adhesive allows the first light transmitted through the first translucent member to be transmitted and efficiently incident on the wavelength conversion element, and the second light emitted from the wavelength conversion element to be transmitted and efficiently incident on the first translucent member.

[0125] (Appendix 5) Further comprising a second reflecting member that reflects the first light and the second light, the first light-transmissive member further has a fifth surface and a sixth surface that intersect with the second surface, the third surface, and the fourth surface, respectively, and face in opposite directions to each other; the second reflecting member is disposed opposite the fifth and sixth surfaces; 5. A light source device according to claim 1,

[0126] According to the configuration of Supplementary Note 5, the conversion efficiency of the first light to the second light can be improved by the second reflecting member reflecting the first light. Also, the extraction efficiency of the second light can be improved by the second reflecting member reflecting the second light.

[0127] (Appendix 6) A support member for supporting the wavelength conversion element is further provided. the wavelength conversion element has a seventh surface facing the opposite side to the first surface, The seventh surface is thermally connected to the support member. 6. A light source device according to any one of claims 1 to 5,

[0128] According to the configuration of Supplementary Note 6, since the heat of the wavelength conversion element is released through the support member, it is possible to suppress the temperature rise of the wavelength conversion element, and therefore it is possible to increase the conversion efficiency of the second light of the wavelength conversion element.

[0129] (Appendix 7) a housing that covers the first optical layer, the first light-transmissive member, and the wavelength conversion element, the housing has an outlet through which the second light emitted from the fourth surface of the first light-transmitting member is extracted to the outside, In a plan view in a normal direction of the fourth surface, the outlet overlaps with the first light-transmissive member and the wavelength conversion element. 7. The light source device according to claim 1,

[0130] According to the configuration of Supplementary Note 7, by providing the housing, it is possible to prevent foreign matter such as dust from adhering to the first optical layer, the first light-transmissive member, and the wavelength conversion element. Also, it is possible to efficiently extract the second light to the outside through the extraction port.

[0131] (Appendix 8) A second light source that is disposed on the opposite side of the wavelength conversion element from the first light source and emits the first light; a second light-transmissive member disposed between the second light source and the wavelength conversion element and configured to guide the second light converted by the wavelength conversion element; a second optical layer disposed between the second light source and the second light-transmissive member, the second optical layer transmitting the first light and reflecting the second light; Further equipped with the wavelength conversion element has a seventh surface onto which the first light emitted from the second light source is incident via the second optical layer and the second light-transmissive member, and which faces an opposite side to the first surface; the second light-transmissive member has an eighth surface opposite to the seventh surface, and a ninth surface and a tenth surface intersecting the eighth surface and facing in opposite directions; the ninth surface faces the first reflecting member, The second light converted by the wavelength conversion element travels inside the second light-transmissive member and is emitted from the tenth surface. 8. A light source device according to any one of claims 1 to 7.

[0132] According to the configuration of Supplementary Note 8, the amount of the first light incident can be increased by making the first light incident from both the first surface and the seventh surface of the wavelength conversion element. Here, as the length of the wavelength conversion element increases, it becomes more difficult to extract the second light generated on the opposite side to the extraction side. For example, if the length of the wavelength conversion element is increased to expand the area of ​​incidence of the first light, the second light may not be efficiently extracted. In contrast, in this configuration, the amount of incident light of the first light can be increased without increasing the length of the wavelength conversion element, thereby increasing the conversion efficiency of the second light and efficiently extracting the generated second light.

[0133] (Appendix 9) a housing that accommodates the first optical layer, the second optical layer, the first light-transmissive member, the second light-transmissive member, and the wavelength conversion element, the housing has an outlet through which the second light emitted from the fourth surface and the tenth surface is extracted, the outlet overlaps with the first light-transmissive member, the wavelength conversion element, and the second light-transmissive member when viewed in a plan view in a normal direction of the fourth surface. 9. The light source device according to claim 8,

[0134] According to the configuration of Supplementary Note 9, by providing the housing, it is possible to prevent foreign matter such as dust from adhering to the first optical layer, the second optical layer, the first translucent member, the second translucent member, and the wavelength conversion element. Also, it is possible to efficiently extract the second light to the outside through the extraction port.

[0135] (Appendix 10) The wavelength conversion element is made of a transparent phosphor. 10. The light source device according to claim 1,

[0136] According to the configuration of Appendix 10, even when a wavelength conversion element made of a transparent phosphor is used, the amount of incident first light can be increased without increasing the length of the wavelength conversion element, thereby improving the conversion efficiency of the second light and efficiently extracting the generated second light.

[0137] (Appendix 11) The wavelength conversion element is composed of a phosphor having light scattering properties. 10. The light source device according to claim 1,

[0138] According to the configuration of Appendix 11, by using a wavelength conversion element made of a scattering phosphor, the second light can be propagated inside the first translucent member while being repeatedly scattered by the wavelength conversion element and reflected by the first optical layer, and can be efficiently emitted from the fourth surface.

[0139] (Appendix 12) The wavelength conversion element is a yellow phosphor, the first light is blue light; the second light is yellow fluorescent light; the fluorescent light propagates through the first light-transmissive member while being repeatedly scattered by the wavelength conversion element and reflected by the first optical layer, and is emitted from the fourth surface. 12. The light source device according to claim 11,

[0140] According to the configuration of Supplementary Note 12, the yellow fluorescence generated by the wavelength conversion element can be efficiently extracted from the fourth surface.

[0141] (Appendix 13) the wavelength conversion element is a blue phosphor, the first light is ultraviolet light, the second light is blue fluorescent light, the fluorescent light propagates through the first light-transmissive member while being repeatedly scattered by the wavelength conversion element and reflected by the first optical layer, and is emitted from the fourth surface. 12. The light source device according to claim 11.

[0142] According to the configuration of Supplementary Note 13, the blue fluorescence generated by the wavelength conversion element can be efficiently extracted from the fourth surface.

[0143] (Appendix 14) A light source device according to any one of claims 1 to 13; a light modulation device that modulates light from the light source device; a projection optical device that projects the light modulated by the light modulation device. A projector characterized by:

[0144] According to the projector having the configuration of Supplementary Note 14, 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]

[0145] 1...projector, 4B, 4G, 4R...light modulation device, 6...projection optical device, 30...support member, 31, 131...housing, 31k, 131k...extraction port, 33...support portion, 41, 141...first light source, 42...second light source, 50, 150, 250...wavelength conversion element, 50a...front surface (first surface), 50b...rear surface (seventh surface), 51...first light-transmitting member, 51a...rear surface (second surface), 51c...first end surface (third surface), 51d...second end surface (fourth surface), 5 1e...first side surface (fifth surface), 51f...second side surface (sixth surface), 52, 252...first optical layer, 53, 153...first reflecting member, 54...second reflecting member, 100, 101, 102, 103...light source device, 151...second light-transmitting member, 151b...rear surface (eighth surface), 151c...first end surface (ninth surface), 151d...second end surface (tenth surface), 152...second optical layer, E...excitation light (first light), Ur...ultraviolet light (first light), BY, Y...fluorescence (second light).

Claims

1. a first light source that emits a first light in a first wavelength band; a wavelength conversion element that converts the first light into a second light of a second wavelength band different from the first wavelength band; a first light-transmissive member disposed between the first light source and the wavelength conversion element and configured to guide the second light converted by the wavelength conversion element; a first optical layer disposed between the first light source and the first light-transmissive member, the first optical layer transmitting the first light and reflecting the second light; a first reflecting member that reflects the first light and the second light; Equipped with the wavelength conversion element has a first surface to which the first light is incident via the first optical layer and the first light-transmitting member, the first light-transmissive member has a second surface opposing the first surface, and a third surface and a fourth surface intersecting the second surface and facing in opposite directions; The third surface faces the first reflecting member, The second light converted by the wavelength conversion element travels inside the first light-transmitting member and is emitted from the fourth surface. A light source device characterized by:

2. The refractive index of the first light-transmissive member is smaller than the refractive index of the wavelength conversion element.

2. The light source device according to claim 1.

3. The thermal conductivity of the first light-transmissive member is greater than the thermal conductivity of the wavelength conversion element.

2. The light source device according to claim 1.

4. The first light-transmissive member and the wavelength conversion element are fixed by a light-transmissive adhesive.

2. The light source device according to claim 1.

5. a second reflecting member that reflects the first light and the second light, the first light-transmissive member further has a fifth surface and a sixth surface that intersect with the second surface, the third surface, and the fourth surface, respectively, and face in opposite directions to each other; The second reflecting member is disposed opposite the fifth surface and the sixth surface.

2. The light source device according to claim 1.

6. A support member for supporting the wavelength conversion element is further provided. The wavelength conversion element has a seventh surface facing the opposite side to the first surface, The seventh surface is thermally connected to the support member.

6. The light source device according to claim 1, wherein the light source device is a light source unit having a light-emitting diode.

7. a housing that covers the first optical layer, the first light-transmissive member, and the wavelength conversion element, the housing has an outlet through which the second light emitted from the fourth surface of the first light-transmitting member is extracted to the outside, In a planar view in a normal direction of the fourth surface, the outlet overlaps with the first light-transmissive member and the wavelength conversion element.

6. The light source device according to claim 1, wherein the light source device is a light source unit having a light-emitting diode.

8. A second light source that is disposed on an opposite side of the wavelength conversion element from the first light source and emits the first light; a second light-transmissive member disposed between the second light source and the wavelength conversion element and configured to guide the second light converted by the wavelength conversion element; a second optical layer disposed between the second light source and the second light-transmissive member, the second optical layer transmitting the first light and reflecting the second light; Further equipped with the wavelength conversion element has a seventh surface onto which the first light emitted from the second light source is incident via the second optical layer and the second light-transmissive member, the seventh surface facing a side opposite to the first surface; the second light-transmissive member has an eighth surface opposite to the seventh surface, and a ninth surface and a tenth surface intersecting the eighth surface and facing in opposite directions; the ninth surface faces the first reflecting member, The second light converted by the wavelength conversion element travels inside the second light-transmitting member and is emitted from the tenth surface.

6. The light source device according to claim 1, wherein the light source device is a light source unit having a light-emitting diode.

9. a housing that accommodates the first optical layer, the second optical layer, the first light-transmissive member, the second light-transmissive member, and the wavelength conversion element, the housing has an outlet through which the second light emitted from the fourth surface and the tenth surface is extracted, The outlet overlaps with the first light-transmissive member, the wavelength conversion element, and the second light-transmissive member when viewed in a plan view in a normal direction of the fourth surface.

9. The light source device according to claim 8.

10. The wavelength conversion element is made of a transparent phosphor.

6. The light source device according to claim 1, wherein the light source device is a light source unit having a light-emitting diode.

11. The wavelength conversion element is composed of a phosphor having light scattering properties.

6. The light source device according to claim 1, wherein the light source device is a light source unit having a light-emitting diode.

12. The wavelength conversion element is a yellow phosphor, the first light is blue light, the second light is yellow fluorescent light, the fluorescent light propagates through the first light-transmissive member while being repeatedly scattered by the wavelength conversion element and reflected by the first optical layer, and is emitted from the fourth surface.

12. The light source device according to claim 11.

13. the wavelength conversion element is a blue phosphor, the first light is ultraviolet light, the second light is blue fluorescent light, the fluorescent light propagates through the first light-transmissive member while being repeatedly scattered by the wavelength conversion element and reflected by the first optical layer, and is emitted from the fourth surface.

12. The light source device according to claim 11.

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

Images