Wavelength conversion element, light source device, and projector

Abstract

To provide a wavelength conversion element, a light source device, and a projector capable of increasing extraction efficiency of fluorescence.SOLUTION: A wavelength conversion element includes: a substrate having a supporting surface; a first optical member having a first optical layer that transmits first light in a first wavelength range, which is incident from a side opposite to the substrate; a first wavelength conversion layer disposed on the supporting surface and converting the first light emitted from the first optical layer into second light; a second wavelength conversion layer disposed at a first wavelength conversion element side with respect to the first optical layer, and converting the first light into third light; a light emitting portion formed by at least the substrate and the first optical member and emitting light; and a second optical member disposed at the light emitting portion and having a second optical layer that reflects the first light and transmits the second light and the third light. The first optical layer is inclined with respect to a light incident surface and reflects the second light and the third light, and the second wavelength conversion layer converts a part of the first light emitted from the first wavelength conversion layer into the third light.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a wavelength conversion element, a light source device, and a projector.

Background Art

[0002] Conventionally, a light source device has been proposed that generates illumination light using fluorescence emitted from a phosphor when the phosphor is irradiated with excitation light emitted from a light source. For example, Patent Document 1 below discloses a light source device using a reflective phosphor wheel that emits fluorescence from a surface on which excitation light is incident.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above light source device, there is room for improvement in efficiently extracting fluorescence as illumination light. Therefore, the above light source device has a problem that the extraction efficiency of fluorescence decreases.

Means for Solving the Problems

[0005] In order to solve the above problems, according to one aspect of the present invention, there is provided a wavelength conversion element including a substrate having a support surface, a first optical member having a first optical layer facing the support surface and transmitting first light in a first wavelength band incident from the side opposite to the substrate, a first wavelength conversion layer disposed on the support surface, having an incident surface on which the first light emitted from the first optical layer is incident, and converting the first light into second light in a second wavelength band different from the first wavelength band, a second wavelength conversion layer disposed on the side of the first wavelength conversion element with respect to the first optical layer, and converting the first light into third light in a third wavelength band different from the first wavelength band, a light emitting unit formed at least by the substrate and the first optical member and emitting light, and a second optical member disposed in the light emitting unit and having a second optical layer that reflects the first light and transmits the second light and the third light. The first optical layer is inclined with respect to the incident surface, reflects the second light and the third light, and the second wavelength conversion layer converts a part of the first light emitted from the first wavelength conversion layer into the third light.

[0006] According to a second aspect of the present invention, there is provided a light source device including a light source that emits the first light and the wavelength conversion element according to the first aspect of the present invention.

[0007] According to a third aspect of the present invention, there is provided a projector including the light source device according to the second aspect of the present invention, 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

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show enlarged portions of characteristic parts for ease of understanding of the characteristics, and the dimensional ratios of each component are not necessarily the same as the actual ones.

[0010] (First Embodiment) An example of the projector according to this embodiment will be described. FIG. 1 is a diagram showing a schematic configuration of the projector according to this embodiment. As shown in FIG. 1, the projector 1 of this embodiment is a projection type image display device that displays a color image on the screen SCR. The projector 1 includes a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a synthesis optical system 5, a projection optical device 6, a first light source device (light source device) 20, and a second light source device 21. Note that the first light source device 20 corresponds to an embodiment of the light source device of the present invention.

[0011] The color separation optical system 3 separates the yellow illumination light WL from the first light source device 20 into red light LR and green light LG. The color separation optical system 3 includes a dichroic mirror 7, a first reflection mirror 8a, and a second reflection mirror 8b.

[0012] The dichroic mirror 7 separates the illumination light WL into red light LR and green light LG. The dichroic mirror 7 transmits the red light LR and reflects the green light LG among the illumination light WL. The second reflection mirror 8b reflects the green light LG toward the light modulation device 4B. The first reflection mirror 8a is disposed in the optical path of the red light LR and reflects the red light LR that has passed through the dichroic mirror 7 toward the light modulation device 4R.

[0013] On the other hand, the blue light LB from the second light source device 21 is reflected by the reflection mirror 9 toward the optical modulation device 4B.

[0014] Here, the configuration of the second light source device 21 will be described. The second light source device 21 includes a light source 81, a condenser lens 82, a diffuser plate 83, a rod lens 84, and a relay lens 85. The light source 81 is composed of at least one semiconductor laser and emits blue light LB composed of laser light. Note that the light source 81 is not limited to a semiconductor laser and may be an LED that emits blue light.

[0015] The condenser lens 82 is a convex lens and makes the blue light LB enter the diffuser plate 83 in a state where the blue light LB is substantially condensed. The diffuser plate 83 diffuses the blue light LB from the light source 81 with a predetermined diffusion degree to generate blue light LB having a uniform light distribution similar to the illumination light WL emitted from the first light source device 20. As the diffuser plate 83, for example, ground glass made of optical glass can be used.

[0016] The blue light LB diffused by the diffuser plate 83 enters the rod lens 84. The rod lens 84 is prismatic and extends along the illumination optical axis ax2 direction of the second light source device 21, and has an incident end face 84a provided at one end and an emission end face 84b provided at the other end. The diffuser plate 83 is fixed to the incident end face 84a of the rod lens 84 via an optical adhesive (not shown). It is desirable that the refractive index of the diffuser plate 83 and the refractive index of the rod lens 84 be as close as possible.

[0017] The blue light LB propagates inside the rod lens 84 by total reflection and is emitted from the emission end face 84b in a state where the uniformity of the illuminance distribution is improved. The blue light LB emitted from the rod lens 84 enters the relay lens 85. The relay lens 85 makes the blue light LB with improved uniformity of the illuminance distribution by the rod lens 84 enter the reflection mirror 9.

[0018] The shape of the exit end face 84b of the rod lens 84 is a rectangular shape that is approximately similar to the shape of the image formation region of the optical modulation device 4B. As a result, the blue light LB emitted from the rod lens 84 efficiently enters the image formation region of the optical modulation device 4B.

[0019] The optical modulation device 4R modulates the red light LR according to the image information and forms image light corresponding to the red light LR. The optical modulation device 4G modulates the green light LG according to the image information and forms image light corresponding to the green light LG. The optical modulation device 4B modulates the blue light LB according to the image information and forms image light corresponding to the blue light LB.

[0020] For the optical modulation device 4R, the optical modulation device 4G, and the optical modulation device 4B, for example, transmissive liquid crystal panels are used. Also, polarizing plates (not shown) are respectively arranged on the incident side and the exit side of the liquid crystal panel, and the configuration is such that only linearly polarized light in a specific direction is allowed to pass through.

[0021] Field lenses 10R, 10G, and 10B are respectively arranged on the incident sides of the optical modulation device 4R, the optical modulation device 4G, and the optical modulation device 4B. The field lenses 10R, 10G, and 10B parallelize the red light LR, the green light LG, and the blue light LB that enter the respective optical modulation devices 4R, 4G, and 4B. light beam parallelize it.

[0022] When the image light emitted from the optical modulation device 4R, the optical modulation device 4G, and the optical modulation device 4B enters the combined optical system 5, the combined optical system 5 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. For example, a cross dichroic prism is used for the combined optical system 5.

[0023] The projection optical device 6 is composed of a plurality of lenses. The projection optical device 6 enlarges and projects the image light combined by the combined optical system 5 toward the screen SCR. Thereby, an image is displayed on the screen SCR.

[0024] (First light source device) FIG. 2 is a schematic configuration diagram of the first light source device 20. In the following drawings including FIG. 2, each component of the first light source device 20 will be described using the XYZ coordinate system as necessary. The X axis is an axis parallel to the optical axis ax3 of the light source 22, the Y axis is orthogonal to the optical axis ax3 of the light source 22 and parallel to the illumination optical axis ax1 of the first light source device 20, and the Z axis is an axis orthogonal to the X axis and the Y axis respectively. That is, the optical axis ax3 and the illumination optical axis ax1 are in the same plane, and the optical axis ax3 is orthogonal to the illumination optical axis ax1.

[0025] As shown in FIG. 2, the first light source device 20 includes a light source 22, a homogenizer optical system 23, a condenser optical system 24, a wavelength conversion element 25, a pickup optical system 26, an integrator optical system 35, a polarization conversion element 36, and a superimposing lens 37.

[0026] The light source 22 includes a light emitting part 201 and a collimating lens 202. The light emitting part 201 is composed of a plurality of semiconductor lasers. The light emitting part 201 emits a plurality of light beams E. The light beam E is light having a blue wavelength band (first wavelength band) of 400 nm to 480 nm, for example, a light beam having a peak wavelength of 455 nm.

[0027] The collimating lens 202 is arranged corresponding to the light emitting part 201. The collimating lens 202 converts the light beam E emitted from the light emitting part 201 into parallel light. The number of the light emitting part 201 and the collimating lens 202 is not particularly limited. In this way, the light source 22 emits excitation light (first light) EL in a blue wavelength band (first wavelength band) composed of parallel light beams. In the present embodiment, the light source 22 emits linearly polarized blue light as the excitation light EL.

[0028] In the first light source device 20 of the present embodiment, the light source 22, the homogenizer optical system 23, the condenser optical system 24, and the wavelength conversion element 25 are arranged on the optical axis ax3 of the light source 22.

[0029] The excitation light EL emitted from the light source 22 enters the homogenizer optical system 23. The homogenizer optical system 23 is composed of, for example, a lens array 23a and a lens array 23b. The lens array 23a includes a plurality of small lenses 23am, and the lens array 23b includes a plurality of small lenses 23bm.

[0030] The lens array 23a separates the excitation light EL into a plurality of small light beams. The small lenses 23am of the lens array 23a form images of the small light beams on the corresponding small lenses 23bm of the lens array 23b. The lens array 23b, together with the condensing optical system 24 described later, superimposes the images of the respective small lenses 23am of the lens array 23a on the first phosphor layer 251 of the wavelength conversion element 25. The condensing optical system 24 cooperates with the homogenizer optical system 23 to equalize the illuminance distribution of the excitation light EL incident on the first phosphor layer 251 of the wavelength conversion element 25. Note that the condensing optical system 24 is composed of one or a plurality of lenses.

[0031] The wavelength conversion element 25 generates fluorescence YL by being excited by the excitation light EL incident from the light source 22 toward the +X side, and emits the generated fluorescence YL from the light emission unit 260.

[0032] Subsequently, the configuration of the wavelength conversion element 25 will be described in detail. FIG. 3 is a perspective view showing the main part configuration of the wavelength conversion element 25. FIG. 4 is a front view of the wavelength conversion element 25 viewed from the +Y side. FIG. 5 is a cross-sectional view of the wavelength conversion element 25 taken along a plane in the XY plane.

[0033] As shown in FIGS. 3 to 5, the wavelength conversion element 25 of the present embodiment includes a first phosphor layer (first wavelength conversion layer) 251, a substrate 252, a mirror layer 253, a first optical member 254, a second optical member 257, a third optical member 255, a fourth optical member 256, a second phosphor layer (second wavelength conversion layer) 258, and a light emission unit 260. The light emitting portion 260 of the present embodiment is an opening formed at each end face on the +Y side of the substrate 252, the first optical member 254, the third optical member 255, and the fourth optical member 256. The light emitting portion 260 emits fluorescence generated by the first phosphor layer 251 and the second phosphor layer 258.

[0034] In the wavelength conversion element 25 of the present embodiment, the first phosphor layer 251 and the second phosphor layer 258 are accommodated in an accommodation space S surrounded by the substrate 252, the first optical member 254, the second optical member 257, the third optical member 255, and the fourth optical member 256. For example, an air layer AR is provided in the accommodation space S.

[0035] The substrate 252 has a support surface 2521 that supports the first phosphor layer 251. The support surface 2521 is a plane parallel to the YZ plane. The substrate 252 is thermally connected to the first phosphor layer 251. The substrate 252 is, for example, a metal plate with excellent heat dissipation properties such as aluminum or copper. Since the substrate 252 is thermally connected to the first phosphor layer 251, the first phosphor layer 251 is cooled by releasing the heat of the first phosphor layer 251.

[0036] The first phosphor layer 251 is supported by the support surface 2521 of the substrate 252. The first phosphor layer 251 is a plate-shaped phosphor including a surface (light incident surface) 2511, a side surface 2512, and a back surface 2513. The surface 2511 is the surface on which the excitation light EL is incident. The side surface 2512 is a surface that intersects the surface 2511. The side surface 2512 may be orthogonal to the surface 2511. The back surface 2513 is the surface opposite to the surface 2511.

[0037] The first phosphor layer 251 contains phosphor particles that are excited by the excitation light EL and emit fluorescence (second light) YL, which is yellow light having a yellow wavelength band (second wavelength band) of, for example, 550 to 640 nm. As the phosphor particles, for example, a YAG (yttrium aluminum garnet) - based phosphor can be used. Note that the material for forming the phosphor particles may be one type, or particles formed by mixing two or more materials may be used as the phosphor particles. As the first phosphor layer 251, for example, a phosphor layer in which phosphor particles are dispersed in an inorganic binder such as alumina, or a phosphor layer in which phosphor particles are sintered without using a binder may be used. The first phosphor layer 251 contains a plurality of scatterers K1. As the scatterer K1, pores or transmissive particles having a refractive index different from that of the phosphor are used. In the case of this embodiment, the scatterer K1 is pores.

[0038] The mirror layer 253 is provided between the substrate 252 and the first phosphor layer 251. The area of the mirror layer 253 is larger than the area of the back surface 2513 of the first phosphor layer 251. In the case of this embodiment, the mirror layer 253 is provided on the support surface 2521 located within the accommodation space S. That is, the mirror layer 253 is provided around the first phosphor layer 251 on the support surface 2521 of the substrate 252. The first phosphor layer 251 is joined to the support surface 2521 of the substrate 252 via the mirror layer 253. The mirror layer 253 is composed of, for example, a metal layer or a dielectric layer. Note that the mirror layer 253 may be provided over the entire area of the support surface 2521, that is, even outside the accommodation space S. Also, a part of the mirror layer 253 may be directly formed on the back surface 2513 of the first phosphor layer 251.

[0039] The first optical member 254 is arranged so as to face the support surface 2521 of the substrate 252. That is, the first optical member 254 is arranged so as to face the surface 2511 of the first phosphor layer 251. The first optical member 254 is arranged so as not to contact the first phosphor layer 251.

[0040] The first optical member 254 is disposed in a state inclined with respect to the surface 2511 of the first phosphor layer 251. The angle formed by the first optical member 254 with respect to the surface 2511 of the first phosphor layer 251 is set to an acute angle.

[0041] The first optical member 254 includes a light-transmissive substrate 2541, a first optical layer 2542, and a third optical layer 2543. The light-transmissive substrate 2541 is made of a light-transmissive member such as alumina, sapphire, glass, or the like.

[0042] The third optical layer 2543 is provided on the outer surface of the light-transmissive substrate 2541, that is, on the side of the light source 22 with respect to the first optical layer 2542. The third optical layer 2543 is a polarization separation layer having a polarization separation characteristic of separating into P-polarized light and S-polarized light by transmitting P-polarized light (light in the first wavelength band polarized in the first direction) among the light in the blue wavelength band and reflecting S-polarized light (light in the first wavelength band polarized in the second direction different from the first direction).

[0043] In the case of this embodiment, the light source 22 is configured to emit, as excitation light EL, P-polarized light (light polarized in the first direction) with respect to the third optical layer 2543. Therefore, the excitation light EL emitted from the light source 22 passes through the third optical layer 2543.

[0044] The excitation light EL that has passed through the third optical layer 2543 is incident on the inner surface of the first optical member 254, that is, the first optical layer 2542 provided on the side of the first phosphor layer 251. The first optical layer 2542 is composed of a dichroic layer having a characteristic of transmitting the excitation light EL from the light source 22 incident from the side opposite to the substrate 252 and reflecting the fluorescent lights YL and YL1 (second light and third light) described later. The first optical layer 2542 faces the support surface 2521 of the substrate 252. The excitation light EL passes through the first optical member 254 and is incident on the second phosphor layer 258.

[0045] The second phosphor layer 258 is disposed on the side of the first phosphor layer 251 with respect to the first optical member 254, that is, on the side of the first phosphor layer 251 with respect to the first optical layer 2542. In the case of this embodiment, the second phosphor layer 258 is provided on the first optical layer 2542.

[0046] The second phosphor layer 258 is a plate-shaped phosphor including a surface (light incident surface) 2581, a side surface 2582, and a back surface 2583. The back surface 2583 abuts on the first optical layer 2542 and is the surface on which the excitation light EL is incident. The side surface 2582 is a surface intersecting the surface 2581. The side surface 2582 may be orthogonal to the surface 2581. The surface 2581 is the surface opposite to the back surface 2583.

[0047] In the case of this embodiment, the second phosphor layer 258 is composed of the same phosphor material as the first phosphor layer 251. The second phosphor layer 258 converts the excitation light EL into yellow light fluorescence YL1 having a yellow wavelength band different from that of the blue wavelength band (first wavelength band), for example, 550 to 640 nm. In this embodiment, the yellow wavelength band (third wavelength band) of the fluorescence YL1 emitted by the second phosphor layer 258 is the same as the yellow wavelength band (second wavelength band) of the fluorescence YL emitted by the first phosphor layer 251.

[0048] The second phosphor layer 258 includes a plurality of scatterers K2. As the scatterer K2, pores or transmissive particles having a refractive index different from that of the phosphor are used. In the case of this embodiment, the scatterer K2 is pores.

[0049] In this embodiment, the degree of light scattering in the second phosphor layer 258 is smaller than the degree of light scattering in the first phosphor layer 251. The degree of light scattering can be adjusted by the number of scatterers contained in the phosphor. In the case of this embodiment, the number of scatterers K2 contained in the second phosphor layer 258 is smaller than the number of scatterers K1 contained in the first phosphor layer 251. For example, by using a single crystal phosphor, a second phosphor layer 258 with a small number of scatterers can be realized. Since the second phosphor layer 258 suppresses backward scattering of light compared to the first phosphor layer 251, the excitation light E incident from the light source 22 travels through the phosphor without being scattered and is easily transmitted.

[0050] Also, in the case of this embodiment, the thickness H2 of the second phosphor layer 258 is smaller than the thickness H1 of the first phosphor layer 251. The thickness of the second phosphor layer 258 is the dimension along the normal direction of the surface on which the second phosphor layer 258 is provided (the surface of the first optical layer 2542 of the first optical member 254), and the thickness of the first phosphor layer 251 is the dimension along the normal direction of the support surface 2521 on which the first phosphor layer 251 is provided. In other words, the thickness H2 of the second phosphor layer 258 is the dimension along the normal direction of the surface 2581 (light incident surface) of the second phosphor layer 258, and the thickness H1 of the first phosphor layer 251 is the dimension along the normal direction of the surface 2511 (light incident surface) of the first phosphor layer 251.

[0051] When the thickness of the phosphor becomes thinner, it becomes easier for the excitation light to be emitted from the phosphor before being converted into fluorescence. In this embodiment, as described above, by suppressing the backscattering and thickness of the second phosphor layer 258 with respect to the first phosphor layer 251, the fluorescence conversion efficiency in the excitation light EL is suppressed. As a result, most of the excitation light EL from the light source 22 is transmitted through the second phosphor layer 258 without being converted into fluorescence in the second phosphor layer 258 and is emitted, and enters the first phosphor layer 251 supported by the support surface 2521 of the substrate 252.

[0052] The third optical member 255 includes a base material 2551 and a fourth optical layer 2552. As the material for forming the base material 2551, for example, glass is used. The fourth optical layer 2552 is formed on the inner surface of the base material 2551. The fourth optical layer 2552 is composed of, for example, a metal layer or a dielectric layer.

[0053] The third optical member 255 is disposed so as to intersect the support surface 2521 of the substrate 252 and the first optical member 254. The third optical member 255 is disposed such that the fourth optical layer 2552 intersects the support surface 2521 and the first optical layer 2542. The third optical member 255 may be orthogonal to the support surface 2521 of the substrate 252 and the first optical member 254. The fourth optical layer 2552 may be orthogonal to the support surface 2521 and the first optical layer 2542. The third optical member 255 is disposed so that its thickness direction coincides with the Z-axis direction. The third optical member 255 is disposed in the vicinity of the +Z side of the first phosphor layer 251 and the second phosphor layer 258. Therefore, a part of the fluorescence YL, YL1 emitted from the first phosphor layer 251 or the second phosphor layer 258 toward the +Z side is reflected by the fourth optical layer 2552 of the third optical member 255. The third optical member 255 reflects not only the fluorescence YL, YL1 but also the excitation light EL.

[0054] The third optical member 255 is trapezoidal plate-shaped. As shown in FIG. 3, the third optical member 255 includes a first end face 55a forming a trapezoidal upper bottom, a second end face 55b forming a trapezoidal lower bottom, a third end face 55c connecting the first end face 55a and the second end face 55b on the +X side, and a fourth end face 55d connecting the first end face 55a and the second end face 55b on the -X side. Note that the first end face 55a, the second end face 55b, the third end face 55c, and the fourth end face 55d are all flat surfaces. The third end face 55c is a surface facing the substrate 252. The fourth end face 55d is a surface on the side opposite to the third end face 55c in the base material 2551. The first optical member 254 is in contact with the fourth end face 55d. The first optical member 254 is placed on the fourth end face 55d. The first optical layer 2542 is in contact with the fourth end face 55d. The translucent substrate 2541 is placed on the fourth end face 55d via the first optical layer 2542.

[0055] Here, when glass is used as the material of the base material 2551, chamfering processing for preventing chipping by removing sharp portions is required. In the present embodiment, by making the third optical member 255 trapezoidal plate-shaped, chamfering processing is made unnecessary, thereby improving the workability of the base material 2551.

[0056] In the case of this embodiment, a part of the third optical member 255 is embedded in the substrate 252. Therefore, the third optical member 255 is firmly supported by the substrate 252. A part of the end portion on the +X side of the third optical member 255 is fitted into a groove 2524 formed in the support surface 2521 of the substrate 252. An adhesive may be filled in the gap between the third optical member 255 and the groove 2524.

[0057] Specifically, for the third optical member 255, the entire first end face 55a and the third end face 55c and a part of the second end face 55b are fitted into the groove 2524. Among the fourth end face 55d, the end side 55d1 located on the most -Y side and along the Z direction is flush with the support surface 2521 of the substrate 252. Thereby, the fourth end face 55d and the support surface 2521 of the substrate 252 are smoothly connected. Also, on the +Y side, the second end face 55b is flush with the end face 52 of the substrate 252.

[0058] The fourth optical member 256 has the same configuration as the third optical member 255. That is, the fourth optical member 256 includes a base material 2561 and a fifth optical layer 2562. The fifth optical layer 2562 is formed on the inner surface of the base material 2561. The fifth optical layer 2562 is composed of, for example, a metal layer or a dielectric layer.

[0059] The fourth optical member 256 intersects the support surface 2521 of the substrate 252 and the first optical member 254, and is arranged to face the third optical member 255. The fourth optical member 256 is arranged such that the fifth optical layer 2562 intersects the support surface 2521 and the first optical layer 2542 and faces the fourth optical layer 2552. The fourth optical member 256 may be orthogonal to the support surface 2521 of the substrate 252 and the first optical member 254. The fifth optical layer 2562 may be orthogonal to the support surface 2521 and the first optical layer 2542. The fourth optical member 256 is arranged such that its thickness direction coincides with the Z-axis direction. The fourth optical member 256 is arranged in the vicinity of the -Z side of the first phosphor layer 251 and the second phosphor layer 258. Therefore, the fluorescence YL, YL1 emitted from the first phosphor layer 251 or the second phosphor layer 258 toward the -Z side and incident on the fourth optical member 256 is reflected by the fifth optical layer 2562 of the fourth optical member 256. The fourth optical member 256 reflects not only the fluorescence YL, YL1 but also the excitation light EL.

[0060] The fourth optical member 256 has the same trapezoidal plate shape as the third optical member 255. The fourth optical member 256 includes a first end face 56a forming the upper bottom of the trapezoidal shape, a second end face 56b forming the lower bottom of the trapezoidal shape, a third end face 56c connecting the first end face 56a and the second end face 56b on the +X side, and a fourth end face 56d connecting the first end face 56a and the second end face 56b on the -X side. Note that the first end face 56a, the second end face 56b, the third end face 56c, and the fourth end face 56d are all flat surfaces. The third end face 56c is the face facing the substrate 252. The fourth end face 56d is the face on the opposite side of the third end face 56c in the base material 2561. The first optical member 254 is in contact with the fourth end face 56d. The first optical member 254 is placed on the fourth end face 56d. The first optical layer 2542 is in contact with the fourth end face 56d. The translucent substrate 2541 is placed on the fourth end face 56d via the first optical layer 2542.

[0061] In the case of this embodiment, a part of the fourth optical member 256 is embedded in the substrate 252, so that the fourth optical member 256 is firmly supported by the substrate 252. A part of the +X side end of the fourth optical member 256 is fitted into a groove 2524 formed in the support surface 2521 of the substrate 252. An adhesive may be filled in the gap between the fourth optical member 256 and the groove 2524.

[0062] Specifically, for the fourth optical member 256, the entire first end face 56a and the third end face 56c, and a part of the second end face 56b are fitted into the groove 2524. Among the fourth end face 56d, the edge 56d1 along the Z direction, which is located on the most -Y side, is flush with the support surface 2521 of the substrate 252. Thereby, the fourth end face 56d and the support surface 2521 of the substrate 252 are smoothly connected. Also, on the +Y side, the second end face 56b is flush with the end face 52 of the substrate 252.

[0063] In this embodiment, the first optical member 254 is supported by the third optical member 255 and the fourth optical member 256. The first optical member 254 is adhesively fixed to the third optical member 255 and the fourth optical member 256. Specifically, the first optical member 254 is provided so as to span between the fourth end face 55d of the third optical member 255 and the fourth end face 56d of the fourth optical member 256. On the -Y side, the inner edge 54a of the first optical member 254 is in contact with the support surface 2521 of the substrate 252.

[0064] Based on such a configuration, the wavelength conversion element 25 of this embodiment forms the light emitting portion 260 by closing the -Y side and opening the +Y side with the substrate 252, the first optical member 254, the third optical member 255, and the fourth optical member 256. Therefore, the wavelength conversion element 25 can prevent light leakage from the side opposite to the light emitting portion 260 in the fluorescent YL and can efficiently emit light from the light emitting portion 260.

[0065] As shown in FIG. 5, in the wavelength conversion element 25 of the present embodiment, the second optical member 257 is disposed so as to cover the light emitting portion 260. The second optical member 257 includes a translucent substrate 2571 and a second optical layer 2572. The translucent substrate 2571 is composed of, for example, a thin glass plate. The second optical layer 2572 is composed of, for example, a dichroic layer that transmits fluorescence (second light) YL and fluorescence (third light) YL1 having a yellow wavelength band (second wavelength band) of 550 to 640 nm and reflects light in a blue wavelength band including excitation light EL. Therefore, the light emitting portion 260 can selectively extract yellow light including fluorescence YL and YL1 as illumination light WL by the second optical member 257.

[0066] The excitation light EL is incident on the first phosphor layer 251 so as to be condensed on the surface 2511. The first phosphor layer 251 is excited by the excitation light EL and emits fluorescence YL by Lambert emission.

[0067] A part of the fluorescence YL emitted from the first phosphor layer 251 is incident on a second phosphor layer 258 provided on the first phosphor layer 251 side of the first optical member 254 disposed opposite to the surface 2511 of the first phosphor layer 251. At least a part of the fluorescence YL incident on the second phosphor layer 258 is backscattered by a plurality of scatterers K2 in the second phosphor layer 258, then travels toward the light emitting portion 260, and is emitted through the second optical member 257 covering the light emitting portion 260.

[0068] A part of the fluorescence YL emitted from the first phosphor layer 251 passes through the second phosphor layer 258 and is incident on the first optical member 254. The fluorescence YL incident on the first optical member 254 is reflected by the first optical layer 2542. At least a part of the fluorescence YL reflected by the first optical layer 2542 travels toward the light emitting portion 260 and is emitted through the second optical member 257 covering the light emitting portion 260.

[0069] A part of the fluorescence YL emitted from the second phosphor layer 258 or the first optical member 254 is incident on the support surface 2521 of the substrate 252 and is reflected by the mirror layer 253 formed on the support surface 2521. At least a part of the fluorescence YL reflected by the mirror layer 253 travels toward the light emitting portion 260 and is emitted through the second optical member 257 covering the light emitting portion 260.

[0070] In addition, a part of the fluorescence YL emitted from the second phosphor layer 258 or the first optical member 254 is incident on the third optical member 255 or the fourth optical member 256 via the mirror layer 253, or is directly incident on the third optical member 255 or the fourth optical member 256. A part of the fluorescence YL is reflected by the third optical member 255 or the fourth optical member 256, travels toward the light emitting portion 260, and is emitted through the second optical member 257 covering the light emitting portion 260.

[0071] Note that a part of the fluorescence YL emitted from the second phosphor layer 258 or the first optical member 254 propagates in the direction opposite to the light emitting portion 260 (-Y side), but after repeated reflections, it eventually travels toward the light emitting portion 260 and is emitted through the second optical member 257 covering the light emitting portion 260. In this way, in the wavelength conversion element 25 of the present embodiment, the fluorescence YL generated in the first phosphor layer 251 can be emitted from the light emitting portion 260.

[0072] In the present embodiment, a part of the excitation light EL is backscattered within the first phosphor layer 251. Also, a part of the excitation light EL is reflected on the surface of the first phosphor layer 251. The excitation light emitted from the first phosphor layer 251 by being backscattered or reflected in the first phosphor layer 251 in this way is referred to as excitation light EL1.

[0073] At least a part of the excitation light EL1 is incident on the second phosphor layer 258 disposed to face the surface 2511 of the first phosphor layer 251. Most of the excitation light EL1 is a component backscattered by the first phosphor layer 251. Since the backscattered light is emitted in various directions, it is efficiently incident on the second phosphor layer 258. At least a part of the excitation light EL1 incident on the second phosphor layer 258 is efficiently converted into fluorescence YL1 and radiated from the back surface 2583 of the second phosphor layer 258 in Lambertian emission.

[0074] Here, since the thickness of the second phosphor layer 258 is thinner than that of the first phosphor layer 251, a part of the excitation light EL1 may pass through the second phosphor layer 258 and reach the third optical layer 2543. The component of the excitation light EL1 backscattered by the first phosphor layer 251 is unpolarized light in which S-polarized light and P-polarized light are mixed. Therefore, the excitation light EL1 is separated into a P-polarized light component and an S-polarized light component in the third optical layer 2543. Specifically, among the excitation light EL1 incident on the third optical layer 2543, the S-polarized light component EL1s is reflected by the third optical layer 2543, and the P-polarized light component EL1p passes through the third optical layer 2543 and is emitted from the first optical member 254. Note that since the P-polarized light component EL1p emitted to the outside of the wavelength conversion element 25 is extremely small among the excitation light E emitted from the light source 22, there is no problem in practice.

[0075] The S-polarized light component EL1s reflected by the third optical layer 2543 is incident on the second phosphor layer 258 again. Therefore, at least a part of the S-polarized light component EL1s is reflected by the third optical layer 2543 and incident on the second phosphor layer 258, and is reused for the excitation of the fluorescence YL1. Also, a part of the S-polarized light component EL1s is incident from the second phosphor layer 258 on the first phosphor layer 251, and is reused for the excitation of the fluorescence YL.

[0076] In this way, at least a part of the fluorescence YL1 emitted from the second phosphor layer 258 travels toward the light emission part 260 and is emitted through the second optical member 257 covering the light emission part 260. Also, a part of the fluorescence YL1 emitted from the second phosphor layer 258 is incident on the support surface 2521 of the substrate 252 and is reflected by the mirror layer 253 formed on the support surface 2521. The fluorescence YL1 reflected by the mirror layer 253 travels toward the light emitting portion 260 and is emitted through the second optical member 257 covering the light emitting portion 260.

[0077] Also, a part of the fluorescence YL1 emitted from the second phosphor layer 258 is incident on the third optical member 255 or the fourth optical member 256 via the mirror layer 253, or is directly incident on the third optical member 255 or the fourth optical member 256. A part of the fluorescence YL1 is reflected by the third optical member 255 or the fourth optical member 256, travels toward the light emitting portion 260, and is emitted through the second optical member 257 covering the light emitting portion 260.

[0078] Note that a part of the fluorescence YL1 emitted from the second phosphor layer 258 propagates in the direction opposite to the light emitting portion 260 (-Y side), but by repeating reflections, it eventually travels toward the light emitting portion 260 and is emitted through the second optical member 257 covering the light emitting portion 260. In this way, in the wavelength conversion element 25 of the present embodiment, the fluorescence YL1 generated in the second phosphor layer 258 can be emitted from the light emitting portion 260.

[0079] In the wavelength conversion element 25 of the present embodiment, in the first phosphor layer 251, heat is more likely to accumulate and the temperature is more likely to rise on the -Y side, which is the side opposite to the light emitting portion 260, than on the light emitting portion 260 side where the fluorescence YL is emitted. In contrast, in the wavelength conversion element 25 of the present embodiment, as shown in FIGS. 3 and 5, the substrate 252 that supports the first phosphor layer 251 is adopted to have a shape that is elongated on the side opposite to the light emitting portion 260. Therefore, according to the wavelength conversion element 25 of the present embodiment, the side opposite to the light emitting portion 260 where heat is likely to accumulate in the first phosphor layer 251 can be efficiently cooled. Thus, the first phosphor layer 251 can be efficiently cooled.

[0080] In addition, in the wavelength conversion element 25 of the present embodiment, since the heat of the second phosphor layer 258 is released through the first optical member 254, the second phosphor layer 258 can be efficiently cooled. Therefore, the fluorescence conversion efficiency of the second phosphor layer 258 can be increased.

[0081] The fluorescence YL, YL1 emitted from the wavelength conversion element 25 enters the pickup optical system 26. The pickup optical system 26 is composed of, for example, pickup lenses 26a and 26b. The pickup optical system 26 has a function of picking up the fluorescence YL, YL1 emitted from the wavelength conversion element 25 and parallelizing it. Hereinafter, the fluorescence YL, YL1 parallelized by the pickup optical system 26 is referred to as illumination light WL.

[0082] The illumination light WL enters the integrator optical system 35. The integrator optical system 35 is composed of, for example, a first lens array 35a and a second lens array 35b. The first lens array 35a includes a plurality of first small lenses 35am, and the second lens array 35b includes a plurality of second small lenses 35bm.

[0083] The first lens array 35a separates the illumination light WL into a plurality of small light beams. The first small lens 35am forms an image of the small light beam on the corresponding second small lens 35bm. The integrator optical system 35, in cooperation with a superimposing lens 37 described later, equalizes the illuminance distribution in the image formation region of the light modulation devices 4R and 4G shown in FIG. 1, which is the illuminated region.

[0084] The illumination light WL that has passed through the integrator optical system 35 enters the polarization conversion element 36. The polarization conversion element 36 is composed of, for example, a polarization separation film and a retardation plate (1 / 2 wavelength plate). The polarization conversion element 36 converts the polarization direction in the fluorescence YL into one polarization component.

[0085] The illumination light WL that has passed through the polarization conversion element 36 is incident on the superimposing lens 37. The illumination light WL emitted from the superimposing lens 37 is incident on the color separation optical system 3. The superimposing lens 37 uniformly illuminates by superimposing the plurality of small light beams that constitute the illumination light WL on the illuminated regions of the optical modulation devices 4R and 4G, that is, the image formation region.

[0086] According to the wavelength conversion element 25 according to the present embodiment described above, the following effects can be obtained. The wavelength conversion element 25 of the present embodiment includes a substrate 252 having a support surface 2521, a first optical member 254 having a first optical layer 2542 that transmits the excitation light E incident from the side opposite to the substrate 252 facing the support surface 2521, a first phosphor layer 251 that is disposed on the support surface 2521 and has a surface 2511 on which the excitation light E emitted from the first optical layer 2542 is incident, and converts the excitation light E into fluorescence YL in the yellow wavelength band, a second phosphor layer 258 that is disposed on the first phosphor layer 251 side with respect to the first optical layer 2542 and converts the excitation light E into fluorescence YL1 in the yellow wavelength band, a light emitting portion 260 formed by at least the substrate 252 and the first optical member 254 and that emits light, and a second optical member 257 that has a second optical layer 2572 that reflects the excitation light E and transmits the fluorescence YL and YL1 and is disposed in the light emitting portion 260. The first optical layer 2542 is inclined with respect to the surface 2511, reflects the fluorescence YL and YL1, and the second phosphor layer 258 converts a part of the excitation light E emitted from the first phosphor layer 251 into fluorescence YL1.

[0087] According to the wavelength conversion element 25 of the present embodiment, fluorescence YL can be generated in the first phosphor layer 251 by the excitation light EL that has passed through the second phosphor layer 258, and fluorescence YL1 can be generated in the second phosphor layer 258 by the excitation light EL1 emitted from the first phosphor layer 251 due to backscattering or the like. Therefore, the fluorescence YL and YL1 can be efficiently generated by efficiently using the excitation light E emitted from the light source 22, and the fluorescence YL and YL1 can be efficiently extracted from the light emitting portion 260. Therefore, according to the wavelength conversion element 25 of the present embodiment, bright illumination light WL can be generated by increasing the extraction efficiency of the fluorescence YL and YL1.

[0088] Also, in the wavelength conversion element 25 of the present embodiment, since the area of the light emitting portion 260 can be regarded as the apparent light emitting area of fluorescence, the étendue in the illumination light WL can be reduced. In the wavelength conversion element 25 of the present embodiment, since the étendue can be reduced without reducing the incident area of the excitation light EL on the first phosphor layer 251 or the second phosphor layer 258, it is possible to suppress a decrease in fluorescence conversion efficiency due to an increase in the light density of the excitation light EL on the first phosphor layer 251 or the second phosphor layer 258. According to the wavelength conversion element 25 of the present embodiment, it is possible to generate the illumination light WL composed of bright fluorescence YL and YL1 with a reduced étendue while suppressing an increase in the light density of the excitation light EL.

[0089] In the wavelength conversion element 25 of the present embodiment, the fluorescence YL1 emitted from the second phosphor layer 258 is in the same yellow wavelength band as the fluorescence YL emitted from the first phosphor layer 251. Also, the excitation light E is blue light.

[0090] According to this configuration, it is possible to generate fluorescence YL and YL1 in the yellow wavelength band with the first phosphor layer 251 and the second phosphor layer 258. Thereby, it is possible to generate bright yellow light as the illumination light WL.

[0091] In the wavelength conversion element 25 of the present embodiment, the thickness H2 of the second phosphor layer 258 is smaller than the thickness H1 of the first phosphor layer 251.

[0092] According to this configuration, the excitation light E can efficiently enter the first phosphor layer 251 through the second phosphor layer 258 as compared with the case where the thicknesses of the first phosphor layer 251 and the second phosphor layer 258 are the same.

[0093] In the wavelength conversion element 25 of the present embodiment, the degree of light scattering in the second phosphor layer 258 is smaller than the degree of light scattering in the first phosphor layer 251.

[0094] According to this configuration, by suppressing the backward scattering of light in the second phosphor layer 258 compared to the first phosphor layer 251, the excitation light E can efficiently enter the first phosphor layer 251 through the second phosphor layer 258 when the degree of light scattering in the first phosphor layer 251 and the second phosphor layer 258 is the same.

[0095] In the wavelength conversion element 25 of the present embodiment, the excitation light E incident on the first optical member 254 from the side opposite to the substrate 252 is P-polarized light, and the first optical member 254 is disposed on the side opposite to the substrate 252 with respect to the first optical layer 2542 and further has a third optical layer 2543 that transmits the excitation light EL of the P-polarized component and reflects the excitation light EL of the S-polarized component.

[0096] According to this configuration, the excitation light EL from the light source 22 can be efficiently taken into the first optical member 254. Further, the first optical layer 2542 can be used for re-exciting the first phosphor layer 251 or the second phosphor layer 258 by reflecting the S-polarized component EL1s of the excitation light EL1 emitted from the first phosphor layer 251 and transmitted through the first optical layer 2542 back inside. Therefore, the light utilization efficiency of the excitation light EL emitted from the light source 22 can be further improved.

[0097] In the wavelength conversion element 25 of the present embodiment, it further includes a third optical member 255 having a fourth optical layer 2552 that reflects the excitation light E, the fluorescence YL, YL1, and the third optical member 255 is disposed such that the fourth optical layer 2552 intersects the support surface 2521 and the first optical layer 2542, and a fourth optical member 256 having a fifth optical layer 2562 that reflects the excitation light E, the fluorescence YL, YL1, and the fifth optical layer 2562 intersects the support surface 2521 and the first optical layer 2542 and is disposed opposite to the fourth optical layer 2552. The light emitting portion 260 is formed by the substrate 252, the first optical member 254, the third optical member 255, and the fourth optical member 256.

[0098] According to this configuration, by suppressing light leakage from other than the light emitting portion 260, the illumination light WL can be efficiently emitted from the light emitting portion 260.

[0099] The first light source device 20 of the present embodiment includes a light source 22 that emits excitation light E and a wavelength conversion element 25.

[0100] According to the first light source device 20 of the present embodiment, bright illumination light WL can be emitted by efficiently extracting fluorescence.

[0101] According to the projector 1 according to the present embodiment described above, the following effects can be obtained. The projector 1 of the present embodiment includes a first light source device 20, a second light source device 21, and light modulation devices 4B, 4G, 4R that form image light by modulating blue light LB, green light LG, and red light LR from the first light source device 20 or the second light source device 21 according to image information, and a projection optical device 6 that projects the aforementioned image light. According to the projector 1 of the present embodiment, since it includes the first light source device 20 that generates bright illumination light WL, a high-brightness image can be formed and projected.

[0102] (Second Embodiment) Subsequently, as a second embodiment of the present invention, another configuration of the light source device will be described. Since the difference between the present embodiment and the first embodiment lies in the structure of the wavelength conversion element, the configuration of the wavelength conversion element will be mainly described below. In the present embodiment, the same reference numerals are given to the configurations or members common to the first embodiment, and the detailed description thereof will be omitted.

[0103] FIG. 6 is a cross-sectional view taken along a plane along the XY plane of the wavelength conversion element of the present embodiment. FIG. 6 corresponds to FIG. 5 of the first embodiment. As shown in FIG. 6, the wavelength conversion element 125 of the present embodiment includes a first phosphor layer 251, a substrate 252, a mirror layer 253, a first optical member 254, a second optical member 257A, a third optical member 255, a fourth optical member 256, and a second phosphor layer 1258.

[0104] In this embodiment, the second phosphor layer 1258 is composed of a phosphor material different from that of the first phosphor layer 251. The second phosphor layer 1258 converts the excitation light EL into fluorescence RL, which is red light having a red wavelength band different from the blue wavelength band, for example, 600 to 800 nm. In this embodiment, the red wavelength band (the third wavelength band) of the fluorescence RL emitted by the second phosphor layer 1258 is larger than the yellow wavelength band (the second wavelength band) of the fluorescence YL emitted by the first phosphor layer 251 and the blue wavelength band (the first wavelength band) of the excitation light EL emitted by the light source 22.

[0105] As such a red phosphor, for example, a YAG-based phosphor (any one of Pr:YAG, Eu:YAG, Cr:YAG) in which any one of Pr, Eu, and Cr is dispersed as an activator in (Y 1-x ,Gd x )3(Al,Ga)5O 12 is used. Note that the activator may include one selected from Pr, Eu, and Cr, or may be a co-activator containing a plurality of types selected from Pr, Eu, and Cr.

[0106] In this embodiment, the degree of light scattering in the second phosphor layer 1258 is smaller than that in the first phosphor layer 251. In the case of this embodiment, the number of scatterers K2 contained in the second phosphor layer 1258 is smaller than the number of scatterers K1 contained in the first phosphor layer 251.

[0107] Also, in this embodiment, by making the thickness of the second phosphor layer 1258 smaller than the thickness of the first phosphor layer 251, it is easier for the excitation light EL emitted from the light source 22 to pass through the second phosphor layer 1258.

[0108] In the wavelength conversion element 125 of the present embodiment, the second optical layer 2572A of the second optical member 257A is a dichroic layer that transmits fluorescence (second light) YL having a yellow wavelength band (second wavelength band) of, for example, 550 to 640 nm and fluorescence RL having a red wavelength band (third wavelength band) of 600 to 800 nm and reflects light in a blue wavelength band including excitation light EL. That is, the second optical layer 2572A of the present embodiment is composed of a dichroic layer that transmits a wider band (a band including the yellow wavelength band and the red wavelength band) than the second optical layer 2572 of the first embodiment. Therefore, the second optical member 257A (second optical layer 2572A) disposed in the light emitting portion 260 does not block the emission of fluorescence YL and RL from the light emitting portion 260.

[0109] According to the first light source device 20 according to the present embodiment described above, fluorescence YL which is yellow light is generated in the first phosphor layer 251 by the excitation light EL that has passed through the second phosphor layer 1258, and fluorescence RL which is red light is generated in the second phosphor layer 1258 by the excitation light EL1 emitted from the first phosphor layer 251 due to backscattering or the like.

[0110] As described above, the first light source device 20 of the present embodiment can efficiently generate fluorescence YL and RL by efficiently using the excitation light E emitted from the light source 22, so that fluorescence YL and RL can be efficiently extracted from the light emitting portion 260. Therefore, the first light source device 20 of the present embodiment can generate bright illumination light WL1 by increasing the extraction efficiency of fluorescence YL and RL.

[0111] Here, for example, when generating white illumination light of 6500K, only yellow fluorescence will result in a shortage of red components. In contrast, in the first light source device 20 of the present embodiment, the red component of the illumination light WL1 can be supplemented by the fluorescence RL which is red light generated in the second phosphor layer 1258. Therefore, according to the first light source device 20 of the present embodiment, white illumination light WL1 with high color reproducibility sufficiently containing red components can be generated.

[0112] Note that although one embodiment of the present invention has been described by way of example, the present invention is not necessarily limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0113] For example, in the above embodiment, the case where the excitation light E is made to easily pass through by suppressing the fluorescence conversion amount in the second phosphor layers 258 and 1258 by reducing the scattering amount and thickness of the second phosphor layers 258 and 1258 with respect to the first phosphor layer 251 has been given as an example. However, the fluorescence conversion amount may be controlled by adjusting only one of the scattering amount or thickness of the second phosphor layers 258 and 1258.

[0114] Also, in the above embodiment, the case where the light emitting portion 260 is formed by the substrate 252, the first optical member 254, the third optical member 255, and the fourth optical member 256 has been given as an example. However, the light emitting portion may be formed by at least the substrate 252 and the first optical member 254.

[0115] Also, in the above embodiment, the case where the first optical member 254, the third optical member 255, and the fourth optical member 256 are each constituted by separate members has been given as an example. However, the first optical member 254, the third optical member 255, and the fourth optical member 256 may be integrally formed as a single member.

[0116] Also, in the above embodiment, the case where the second phosphor layers 258 and 1258 are constituted by one plate-shaped phosphor has been given as an example. However, the second phosphor layers 258 and 1258 may be constituted by a plurality of discretely arranged phosphors. Further, when the second phosphor layers 258 and 1258 are constituted by a plurality of phosphors, they may contain both a phosphor that emits yellow light and a phosphor that emits red light.

[0117] In addition, in the above embodiment, the case where the width of the first phosphor layer 251 in the Z direction is narrower than the width of the support surface 2521 located within the accommodation space S is taken as an example. However, the width of the back surface 2513 of the first phosphor layer 251 in the Z direction and the width of the support surface 2521 located within the accommodation space S may be the same. In this case, since the side surface 2512 of the first phosphor layer 251 is in contact with the third optical member 255 and the fourth optical member 256, the fluorescence YL emitted from the side surface 2512 is reflected by the third optical member 255 and the fourth optical member 256 and returned into the first phosphor layer 251. Similarly, the case where the width of the second phosphor layer 258 in the Z direction is narrower than the width of the first optical member 254 located within the accommodation space S is taken as an example. However, the width of the second phosphor layer 258 in the Z direction may be the same as the width of the first optical member 254 in the Z direction.

[0118] In addition, in the above embodiment, the projector 1 including the three light modulation devices 4R, 4G, and 4B is illustrated. However, it is also applicable to a projector that displays a color image with one light modulation device. Furthermore, the light modulation device is not limited to the above-described liquid crystal panel, and for example, a digital micromirror device or the like can also be used.

[0119] In addition, in the above embodiment, an example of applying the light source device according to the present invention to a projector is shown, but it is not limited thereto. The light source device according to the present invention can also be applied to lighting fixtures such as automotive headlights.

[0120] The wavelength conversion element according to an aspect of the present invention may have the following configuration. The wavelength conversion element according to one aspect of the present invention includes a substrate having a support surface, a first optical member having a first optical layer that transmits first light in a first wavelength band incident from the side opposite to the substrate facing the support surface, a first wavelength conversion layer that is disposed on the support surface, has a light incident surface on which the first light emitted from the first optical layer is incident, and converts the first light into second light in a second wavelength band different from the first wavelength band, a second wavelength conversion layer that is disposed on the first wavelength conversion element side with respect to the first optical layer and converts the first light into third light in a third wavelength band different from the first wavelength band, a light emitting portion that is formed by at least the substrate and the first optical member and emits light, and a second optical member that has a second optical layer that reflects the first light and transmits the second light and the third light and is disposed in the light emitting portion. The first optical layer is inclined with respect to the light incident surface, reflects the second light and the third light, and the second wavelength conversion layer converts a part of the first light emitted from the first wavelength conversion layer into the third light.

[0121] In the wavelength conversion element according to one aspect of the present invention, the third wavelength band may be the second wavelength band.

[0122] In the wavelength conversion element according to one aspect of the present invention, the first light may be blue light, and the second light and the third light may be yellow light.

[0123] In the wavelength conversion element according to one aspect of the present invention, the third wavelength band may be larger than the first wavelength band and the second wavelength band.

[0124] In the wavelength conversion element according to one aspect of the present invention, the first light may be blue light, the second light may be yellow light, and the third light may be red light.

[0125] In the wavelength conversion element according to one aspect of the present invention, the thickness of the second wavelength conversion layer may be smaller than the thickness of the first wavelength conversion layer.

[0126] In the wavelength conversion element according to one aspect of the present invention, the degree of light scattering in the second wavelength conversion layer may be smaller than the degree of light scattering in the first wavelength conversion layer.

[0127] In a wavelength conversion element according to one aspect of the present invention, the first light incident on the first optical member from the side opposite to the substrate is polarized in the first direction, and the first optical member is disposed on the side opposite to the substrate with respect to the first optical layer, and may further include a third optical layer that transmits the first light polarized in the first direction and reflects the first light polarized in a second direction different from the first direction.

[0128] In a wavelength conversion element according to one aspect of the present invention, a third optical member having a fourth optical layer that reflects the first light, the second light, and the third light, and the fourth optical layer is disposed so as to intersect the support surface and the first optical layer; and a fourth optical member having a fifth optical layer that reflects the first light, the second light, and the third light, and the fifth optical layer intersects the support surface and the first optical layer and is disposed opposite to the fourth optical layer. The light emitting portion may be configured by the substrate, the first optical member, the third optical member, and the fourth optical member.

[0129] A light source device according to one aspect of the present invention may have the following configuration. A light source device according to one aspect of the present invention includes a light source that emits the first light and a wavelength conversion element according to the above aspect of the present invention.

[0130] A projector according to one aspect of the present invention may have the following configuration. A projector according to one aspect of the present invention includes the light source device according to the above aspect of the present invention, a light modulation device that modulates the light from the light source device according to image information, and a projection optical device that projects the light modulated by the light modulation device.

Description of Reference Numerals

[0131] 1… Projector, 4B, 4G, 4R… Light modulation device, 6… Projection optical device, 20… First light source device (light source device), 22, 81… Light source, 25, 125… Wavelength conversion element, 251… First phosphor layer (first wavelength conversion layer), 252… Substrate, 254… First optical member, 255… Third optical member, 256… Fourth optical member, 257… Second optical member, 258… Second phosphor layer (second wavelength conversion layer), 260… Light emission part, 2511, 2581… Surface (light incident surface), 2542… First optical layer, 2543… Third optical layer, 2552… Fourth optical layer, 2562… Fifth optical layer, 2572, 2572A… Second optical layer, EL… Excitation light (first light), LB… Blue light, LR… Red light, YL… Fluorescence (second light), YL1… Fluorescence (third light).

Claims

1. a substrate having a support surface; a first optical member having a first optical layer that faces the support surface and transmits first light in a first wavelength band incident from the side opposite to the substrate; a first optical member having a first optical layer; a light incident surface that is disposed on the support surface and on which the first light emitted from the first optical layer is incident; a first wavelength conversion layer that has the light incident surface, and that converts the first light into second light in a second wavelength band different from the first wavelength band; a first wavelength conversion layer; a second wavelength conversion layer that is disposed on the first wavelength conversion layer side with respect to the first optical layer, and that converts the first light into third light in a third wavelength band different from the first wavelength band; a second wavelength conversion layer; a light emitting portion that is formed of at least the substrate and the first optical member and emits light; 、 a second optical member that has a second optical layer that reflects the first light and transmits the second light and the third light, and that is disposed in the light emitting portion; a second optical member disposed in the light emitting portion; characterized by having; the first optical layer is inclined with respect to the light incident surface, and reflects the second light and the third light; and; the second wavelength conversion layer converts a part of the first light emitted from the first wavelength conversion layer into the third light; and; a wavelength conversion element, wherein a thickness of the second wavelength conversion layer is smaller than a thickness of the first wavelength conversion layer. A wavelength conversion element characterized by the above.

2. A wavelength conversion element according to claim 1, characterized in that the third wavelength band is the second wavelength band.

3. A wavelength conversion element according to claim 2, characterized in that the first light is blue light, and the second light and the third light are yellow light. A wavelength conversion element characterized by the above.

4. A substrate having a support surface; a first optical member having a first optical layer that faces the support surface and transmits first light in a first wavelength band incident from the side opposite to the substrate; a first optical member having a first optical layer; a light incident surface that is disposed on the support surface and on which the first light emitted from the first optical layer is incident; a first wavelength conversion layer that has the light incident surface, and that converts the first light into second light in a second wavelength band different from the first wavelength band; a first wavelength conversion layer; a second wavelength conversion layer that is disposed on the first wavelength conversion layer side with respect to the first optical layer, and that converts the first light into third light in a third wavelength band different from the first wavelength band; a second wavelength conversion layer; a light emitting portion that is formed of at least the substrate and the first optical member and emits light; 、 a second optical member that has a second optical layer that reflects the first light and transmits the second light and the third light, and that is disposed in the light emitting portion; a second optical member disposed in the light emitting portion; characterized by having; the first optical layer is inclined with respect to the light incident surface, and reflects the second light and the third light; and; the second wavelength conversion layer converts a part of the first light emitted from the first wavelength conversion layer into the third light; Convert it into three lights, The wavelength of the third wavelength band is greater than the wavelength of the first wavelength band and the wavelength of the second wavelength band bigger, A wavelength conversion element characterized by that.

5. A wavelength conversion element according to claim 4, wherein the first light is blue light, the second light is yellow light, and the third light is red light A wavelength conversion element characterized by that.

6. A substrate having a support surface, A first optical member having a first optical layer that transmits first light in a first wavelength band incident from the side opposite to the substrate facing the support surface 1 optical layer, A light incident surface that is disposed on the support surface and on which the first light emitted from the first optical layer is incident A first wavelength having a first wavelength conversion layer that converts the first light into second light in a second wavelength band different from the first wavelength band conversion layer, A second wavelength conversion layer that is disposed on the side of the first wavelength conversion layer with respect to the first optical layer and converts the first light into third light in a third wavelength band different from the first wavelength band band, An optical emission unit that is formed by at least the substrate and the first optical member and emits light 、 A second optical member that has a second optical layer that reflects the first light and transmits the second light and the third light, and is disposed in the light emission unit A second optical member disposed in the light emitting portion, having, The first optical layer is inclined with respect to the light incident surface and reflects the second light and the third light and, The second wavelength conversion layer converts a part of the first light emitted from the first wavelength conversion layer into the third light Convert, The degree of light scattering in the second wavelength conversion layer is smaller than the degree of light scattering in the first wavelength conversion layer smaller, A wavelength conversion element characterized by that.

7. A wavelength conversion element according to any one of claims 1 to 6, The first light incident on the first optical member from the side opposite to the substrate is polarized in a first direction and, The first optical member is disposed on the side opposite to the substrate with respect to the first optical layer, transmits the first light polarized in the first direction, and is polarized in a second direction different from the first direction A wavelength conversion element characterized by further having a third optical layer that reflects the first light.

8. A substrate having a support surface, A first optical member having a first optical layer that transmits first light in a first wavelength band incident from the side opposite to the substrate facing the support surface 1 optical layer, A light incident surface that is disposed on the support surface and on which the first light emitted from the first optical layer is incident A first wavelength having a first wavelength conversion layer that converts the first light into second light in a second wavelength band different from the first wavelength band conversion layer, ​ Disposed on the side of the first wavelength conversion layer with respect to the first optical layer, and converting the first light into third light in a third wavelength band different from the first wavelength band is a second wavelength conversion layer, And a light emitting portion that is formed by at least the substrate and the first optical member and emits light. And has a second optical layer that reflects the first light and transmits the second light and the third light, and is disposed on the light emitting portion is a second optical member, 、 And has a second optical layer that reflects the first light and transmits the second light and the third light, and is disposed on the light emitting portion is a second optical member, And has a second optical layer that reflects the first light and transmits the second light and the third light, and is disposed on the light emitting portion is a second optical member, And has, The first optical layer is inclined with respect to the light incident surface, reflects the second light and the third light, And, The second wavelength conversion layer converts a part of the first light emitted from the first wavelength conversion layer into the third light, And has a fourth optical layer that reflects the first light, the second light, and the third light, and is disposed such that the fourth optical layer intersects the support surface and the first optical layer is a third optical member, And has a fourth optical layer that reflects the first light, the second light, and the third light, and is disposed such that the fourth optical layer intersects the support surface and the first optical layer is a third optical member, And has a fourth optical layer that reflects the first light, the second light, and the third light, and is disposed such that the fourth optical layer intersects the support surface and the first optical layer is a third optical member, And further includes a fourth optical member having a fifth optical layer that reflects the first light, the second light, and the third light, and is disposed such that the fifth optical layer intersects the support surface and the first optical layer and faces the fourth optical layer, And further includes a fourth optical member having a fifth optical layer that reflects the first light, the second light, and the third light, and is disposed such that the fifth optical layer intersects the support surface and the first optical layer and faces the fourth optical layer, And further includes a fourth optical member having a fifth optical layer that reflects the first light, the second light, and the third light, and is disposed such that the fifth optical layer intersects the support surface and the first optical layer and faces the fourth optical layer, The light emitting portion is formed by the substrate, the first optical member, the third optical member, and the fourth optical member, A wavelength conversion element characterized by that.

9. A light source that emits the first light, And a wavelength conversion element according to any one of claims 1 to 8, characterized by that.

10. The light source device according to claim 9, An optical modulation device that modulates the light from the light source device, And a projection optical device that projects the light modulated by the optical modulation device, characterized by that. A projector characterized by that. ​ ​

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