Wavelength conversion device, light source device, and projector

Abstract

To provide a wavelength conversion device that can prevent damage to a wavelength conversion element, a light source device, and a projector.SOLUTION: A wavelength conversion device of the present invention comprises: a substrate that has a first surface; a wavelength conversion element that is arranged on the side of the first surface of the substrate, converts first light in a first wavelength range into second light in a second wavelength range different from the first wavelength range, and has a light emission surface provided on the opposite side of the substrate and emitting the second light; liquid metal that is arranged between the substrate and the wavelength conversion element; and a first regulation part that holds the wavelength conversion element on the substrate, and regulates the position of the wavelength conversion element in a first direction along the normal line of the light emission surface.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In recent years, there have been light source devices that combine a solid-state light source such as a semiconductor laser with a wavelength conversion element having a phosphor layer. In such light source devices, the fluorescence conversion efficiency decreases when the temperature of the phosphor layer increases. For example, in the light source device disclosed in Patent Document 1 below, the phosphor layer is bonded to a heat dissipation substrate with a metal bonding material to increase the cooling efficiency of the phosphor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-123014 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above light source device, the phosphor layer and the heat dissipation substrate have different expansion coefficients, so there is a risk that the phosphor layer may be damaged or peeled off from the substrate due to thermal stress generated when the phosphor layer generates heat. [Means for solving the problem]

[0005] In order to solve the above problem, according to a first aspect of the present invention, there is provided a wavelength conversion device comprising: a substrate having a first surface; a wavelength conversion element arranged on the side of the first surface of the substrate, which converts first light in a first wavelength band into second light in a second wavelength band different from the first wavelength band, and which has a light exit surface arranged on the opposite side of the substrate and which emits the second light; a liquid metal arranged between the substrate and the wavelength conversion element; and a first regulating portion which holds the wavelength conversion element on the substrate and regulates the position of the wavelength conversion element in a first direction along the normal to the light exit surface.

[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 device according to the above aspect, onto which the first light emitted from the light source is incident.

[0007] According to a third aspect of the present invention, there is provided a projector comprising the light source device of the above aspect, an optical modulation device that modulates the light emitted from the light source device in accordance with image information, and a projection optical device that projects the light modulated by the optical modulation device. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a projector according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating a schematic configuration of a light source device. [Figure 3] FIG. 1 is a cross-sectional view showing a configuration of a wavelength conversion device. [Figure 4] FIG. 1 is a plan view showing a configuration of a wavelength conversion device. [Figure 5] FIG. 10 is a cross-sectional view showing the configuration of a wavelength conversion device of a first modified example. [Figure 6A] FIG. 10 is a cross-sectional view showing the configuration of a wavelength conversion device according to a second embodiment. [Figure 6B] FIG. 10 is a perspective view showing the configuration of a wavelength conversion device according to a second embodiment. [Figure 7] FIG. 10 is a cross-sectional view showing the configuration of a wavelength conversion device of a second modified example. [Figure 8A] FIG. 10 is an exploded perspective view showing the configuration of a wavelength conversion device according to a third embodiment. [Figure 8B] FIG. 10 is a cross-sectional view showing the configuration of a wavelength conversion device according to a third embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing the configuration of a wavelength conversion device according to a fourth embodiment. [Figure 10] FIG. 10 is a perspective view showing a configuration in which a capillary force generating portion is formed on a substrate. [Figure 11] FIG. 10 is an exploded perspective view showing the configuration of a wavelength conversion device according to a third modified example. [Figure 12]FIG. 10 is a cross-sectional view showing the configuration of a wavelength conversion device according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the drawings used in the following explanation may show characteristic parts enlarged for convenience in order to make the features easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0010] (First embodiment) First, an example of a projector according to this embodiment will be described. FIG. 1 is a diagram showing a schematic configuration of a projector according to this embodiment. 1, the projector 1 of this embodiment is a projection-type image display device that displays a color image on a screen SCR. The projector 1 includes a light source device 2, a color separation optical system 3, a light modulation device 11R, a light modulation device 11G, and a light modulation device 11B, a combining optical system 5, and a projection optical device 6.

[0011] The color separation optical system 3 separates the illumination light WL into red light LR, green light LG, and blue light LB. The color separation optical system 3 generally includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first total reflection mirror 8a, a second total reflection mirror 8b, and a third total reflection mirror 8c, and a first relay lens 9a and a second relay lens 9b.

[0012] The first dichroic mirror 7a separates the illumination light WL from the light source device 2 into red light LR and other light (green light LG and blue light LB). The first dichroic mirror 7a transmits the separated red light LR and reflects the other light (green light LG and blue light LB). On the other hand, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB, thereby separating the other light into green light LG and blue light LB.

[0013] The first total 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 first dichroic mirror 7a toward the optical modulation device 11R. On the other hand, the second total reflection mirror 8b and the third total reflection mirror 8c are disposed in the optical path of the blue light LB and guide the blue light LB that has passed through the second dichroic mirror 7b toward the optical modulation device 11B. The green light LG is reflected from the second dichroic mirror 7b toward the optical modulation device 11G.

[0014] The first relay lens 9a and the second relay lens 9b are disposed after the second dichroic mirror 7b in the optical path of the blue light LB.

[0015] The light modulation device 11R modulates the red light LR according to image information to form image light corresponding to the red light LR. The light modulation device 11G modulates the green light LG according to image information to form image light corresponding to the green light LG. The light modulation device 11B modulates the blue light LB according to image information to form image light corresponding to the blue light LB.

[0016] For example, a transmissive liquid crystal panel is used for the light modulation device 11R, the light modulation device 11G, and the light modulation device 11B. A polarizing plate (not shown) is disposed on each of the incident side and the exit side of the liquid crystal panel.

[0017] Furthermore, field lenses 10R, 10G, and 10B are arranged on the incident sides of optical modulation device 11R, optical modulation device 11G, and optical modulation device 11B, respectively. Field lenses 10R, 10G, and 10B collimate the red light LR, green light LG, and blue light LB incident on optical modulation device 11R, optical modulation device 11G, and optical modulation device 11B, respectively.

[0018] The image light from the light modulation device 11R, the light modulation device 11G, and the light modulation device 11B is incident on the combining optical system 5. The combining optical system 5 combines the image light corresponding to the red light LR, the green light LG, and the blue light LB, respectively, and emits this combined image light toward the projection optical device 6. The combining optical system 5 uses, for example, a cross dichroic prism.

[0019] The projection optical device 6 is made up of a group of projection lenses, and projects the image light combined by the combining optical system 5 onto the screen SCR in an enlarged form, thereby displaying an enlarged color image on the screen SCR.

[0020] (Light source device) Next, a light source device 2 according to one embodiment of the present invention will be described. Fig. 2 is a diagram showing a schematic configuration of the light source device 2. As shown in Fig. 2, the light source device 2 includes a light source unit 2A, an integrator optical system 31, a polarization conversion element 32, and a superimposing lens 33a. In this embodiment, the integrator optical system 31 and the superimposing lens 33a form a superimposing optical system 33.

[0021] The light source unit 2A includes a light source 21, a collimator optical system 22, an afocal optical system 23, a first retardation plate 28a, a polarization separation element 25, a first focusing optical system 26, a wavelength conversion device 4, a second retardation plate 28b, a second focusing optical system 29, and a diffuse reflection element 30.

[0022] The light source 21, collimator optical system 22, afocal optical system 23, first retardation plate 28a, polarization separation element 25, second retardation plate 28b, second focusing optical system 29, and diffuse reflection element 30 are arranged in sequence on optical axis ax1. Meanwhile, the wavelength conversion device 4, first focusing optical system 26, polarization separation element 25, integrator optical system 31, polarization conversion element 32, and superimposing lens 33a are arranged in sequence on illumination optical axis ax2. The optical axis ax1 and the illumination optical axis ax2 are in the same plane and are perpendicular to each other.

[0023] The light source 21 includes a plurality of semiconductor lasers 211 as solid-state light sources. The plurality of semiconductor lasers 211 are arranged in an array in a plane perpendicular to the optical axis ax1. The semiconductor lasers 211 emit light beams B in a blue wavelength band (first wavelength band) having a peak wavelength of 460 nm, for example. Based on this configuration, the light source 21 of this embodiment emits a blue light beam (first light) BL consisting of the plurality of light beams B.

[0024] The blue light beam BL emitted from the light source 21 enters the collimator optical system 22. The collimator optical system 22 converts the blue light beam BL emitted from the light source 21 into parallel light. The collimator optical system 22 is composed of a plurality of collimator lenses 22a arranged, for example, in an array. The plurality of collimator lenses 22a are arranged corresponding to the plurality of semiconductor lasers 211.

[0025] The blue light beam BL that has passed through the collimator optical system 22 is incident on the afocal optical system 23. The afocal optical system 23 adjusts the beam diameter of the blue light beam BL. The afocal optical system 23 is composed of, for example, a convex lens 23a and a concave lens 23b.

[0026] The blue light beam BL that has passed through the afocal optical system 23 is incident on the first retardation plate 28a. The first retardation plate 28a is, for example, a rotatable half-wave plate. The blue light beam BL emitted from the semiconductor laser 211 is linearly polarized light. By appropriately setting the rotation angle of the first retardation plate 28a, the blue light beam BL that passes through the first retardation plate 28a can be made into a light beam that contains a predetermined ratio of S-polarized component and P-polarized component relative to the polarization separation element 25. By rotating the first retardation plate 28a, the ratio of the S-polarized component and the P-polarized component can be changed.

[0027] The blue light beam BL, which contains an S-polarized component and a P-polarized component and is generated by passing through the first retardation plate 28a, enters the polarization separation element 25. The polarization separation element 25 is formed, for example, by a polarization beam splitter having wavelength selectivity. The polarization separation element 25 also forms an angle of 45° with respect to the optical axis ax1 and the illumination optical axis ax2.

[0028] The polarization separation element 25 has a polarization separation function of separating the blue light beam BL into a light ray BLs having an S-polarized component and a light ray BLp having a P-polarized component relative to the polarization separation element 25. Specifically, the polarization separation element 25 reflects the light ray BLs having an S-polarized component and transmits the light ray BLp having a P-polarized component.

[0029] The polarization separation element 25 also has a color separation function of transmitting the fluorescence YL, which has a wavelength band different from that of the blue light beam BL, regardless of its polarization state.

[0030] The S-polarized light beam BLs emitted from the polarization separation element 25 is incident on the first focusing optical system 26. The first focusing optical system 26 focuses the light beam BLs toward the wavelength conversion device 4.

[0031] In this embodiment, the first focusing optical system 26 is composed of, for example, a first lens 26a and a second lens 26b. The light beam BLs emitted from the first focusing optical system 26 is incident on the wavelength conversion device 4 in a focused state.

[0032] The fluorescence YL generated by the wavelength converter 4 is collimated by the first light-collecting optical system 26 and then enters the polarization separation element 25. The fluorescence YL passes through the polarization separation element 25.

[0033] On the other hand, P-polarized light ray BLp emerging from polarization separation element 25 is incident on second retardation plate 28b. Second retardation plate 28b is composed of a quarter-wave plate arranged in the optical path between polarization separation element 25 and diffuse reflection element 30. Therefore, P-polarized light ray BLp emerging from polarization separation element 25 is converted by second retardation plate 28b into, for example, right-handed circularly polarized blue light BLc1, and then enters second focusing optical system 29. The second light-collecting optical system 29 is composed of, for example, convex lenses 29a and 29b, and causes the blue light BLc1 to be incident on the diffuse reflecting element 30 in a condensed state.

[0034] The diffuse reflecting element 30 is disposed on the opposite side of the polarization separating element 25 from the wavelength conversion device 4, and diffusely reflects the blue light BLc1 emitted from the second focusing optical system 29 toward the polarization separating element 25. It is preferable to use a diffuse reflecting element 30 that can Lambertian-reflect the blue light BLc1 without disturbing the polarization state.

[0035] Hereinafter, the light diffusely reflected by the diffuse reflecting element 30 will be referred to as blue light BLc2. According to this embodiment, blue light BLc2 with a substantially uniform illuminance distribution is obtained by diffusively reflecting blue light BLc1. For example, right-handed circularly polarized blue light BLc1 is reflected as left-handed circularly polarized blue light BLc2.

[0036] The blue light BLc2 is converted into parallel light by the second focusing optical system 29 and then enters the second retardation plate 28b again.

[0037] The left-handed circularly polarized blue light BLc2 is converted by the second retardation plate 28b into S-polarized blue light BLs1. The S-polarized blue light BLs1 is reflected by the polarization separation element 25 towards the integrator optical system 31.

[0038] As a result, the blue light BLs1 is used as illumination light WL together with the fluorescence YL that has passed through the polarization separation element 25. That is, the blue light BLs1 and the fluorescence YL are emitted in the same direction from the polarization separation element 25, and white illumination light WL is generated as a mixture of the blue light BLs1 and the fluorescence (yellow light) YL.

[0039] The illumination light WL is emitted toward the integrator optical system 31. The integrator optical system 31 is composed of, for example, a lens array 31a and a lens array 31b. The lens arrays 31a and 31b are each composed of a plurality of small lenses arranged in an array.

[0040] The illumination light WL transmitted through the integrator optical system 31 is incident on the polarization conversion element 32 . The polarization conversion element 32 is composed of a polarization separation film and a phase difference plate, and converts the illumination light WL containing unpolarized fluorescence YL into linearly polarized light.

[0041] The illumination light WL that has passed through the polarization conversion element 32 is incident on the superimposing lens 33a. The superimposing lens 33a cooperates with the integrator optical system 31 to homogenize the illuminance distribution of the illumination light WL in the illuminated area. In this way, the light source device 2 generates the illumination light WL.

[0042] (Wavelength conversion device) Next, the configuration of the wavelength converter 4 will be described. Fig. 3 is a cross-sectional view showing the configuration of the wavelength converter. Fig. 4 is a plan view showing the configuration of the wavelength converter. Fig. 3 corresponds to the cross section taken along the line III-III in Fig. 4. Fig. 3 illustrates light BLs incident on the wavelength converter 4 as excitation light and fluorescence YL emitted from the wavelength converter 4.

[0043] 3 and 4, the wavelength converter 4 includes a substrate 40, a wavelength conversion element 41, a liquid metal 42, and a first restricting portion 43. The wavelength converter 4 of this embodiment employs a fixed configuration in which the substrate 40 does not rotate, but may employ a rotary configuration in which the substrate 40 rotates.

[0044] The light beam BLs emitted from the first focusing optical system 26 is incident on the wavelength conversion device 4. The wavelength conversion device 4 converts the wavelength of the incident light beam BLs to generate fluorescence YL, which is then emitted toward the first focusing optical system 26. In this embodiment, the fluorescence (second light) YL is, for example, yellow light having a wavelength of 500 to 700 nm (a second wavelength band different from the first wavelength band).

[0045] The substrate 40 has a first surface 40a facing the first focusing optical system 26 and a second surface 40b facing the opposite side to the first surface 40a. The wavelength converter 4 may have a heat dissipation member provided on the second surface 40b of the substrate 40, if necessary.

[0046] The material of the substrate 40 is preferably a material with high thermal conductivity and excellent heat dissipation properties, such as inorganic oxides such as alumina, sapphire, aluminum nitride, and diamond, metals such as aluminum and copper, and carbon graphite. When cost and thermal conductivity are important, it is preferable to use copper as the material of the substrate 40.

[0047] In this embodiment, the substrate 40 is configured as a vapor chamber. A vapor chamber has a structure in which a hollow portion containing a small amount of refrigerant (water) is enclosed and sealed with a thin copper plate. When heat is applied to the substrate 40 configured as a vapor chamber, the water in the hollow portion changes phase to vapor and spreads throughout the hollow portion, diffusing and dissipating the heat. The vapor in the hollow portion returns to water by releasing heat.

[0048] Here, if the vapor chamber is heated too much, the vapor pressure will increase, which may cause deformation of the copper thin plate. Conventionally, when bonding a phosphor layer to a heat dissipation substrate by sintering Ag nanoparticles, heat of about 250°C is applied, which may cause deformation of the vapor chamber. In contrast, in the wavelength conversion device 4 of this embodiment, the use of liquid metal 42 eliminates the need to sinter-bond the phosphor layer 410 and the base material 40, so the vapor chamber can be used as the base material 40.

[0049] The wavelength conversion element 41 is disposed on the first surface 40a side of the base material 40, and includes a phosphor layer (wavelength conversion layer) 410 and a reflecting member 411. In this embodiment, the phosphor layer 410 is made of, for example, ceramics, a ceramic binder and YAG phosphor particles mixed together, or a glass binder and YAG phosphor particles mixed together.

[0050] The reflective member 411 is provided on a rear surface 410a, which is the surface of the phosphor layer 410 facing the base material 40. The reflective member 411 of this embodiment has a multilayer structure including at least a reflection-enhancing layer 412, a reflective layer 413, and a protective layer 414, which are stacked in this order from the rear surface 410a side of the phosphor layer 410 toward the first surface 40a side of the base material 40.

[0051] The reflection-enhancing layer 412 has the effect of improving the efficiency of extracting the fluorescent light YL by virtue of the reflection-enhancing effect of the multilayer film. In this embodiment, the reflection-enhancing layer 412 can be formed from materials such as 、 SiO2, Nb2O5, and Al2O3 were used.

[0052] The reflective layer 413 is a layer that reflects the light BLs or the fluorescence YL that is incident on the reflective member 411. For example, Ag or Al is used as the material of the reflective layer 413. In this embodiment, the reflective layer 413 is formed using an Ag layer that obtains higher reflectance.

[0053] The protective layer 414 is made of an inorganic oxide film or an amorphous film. The protective layer 414 protects the reflective layer 413 from erosion by the liquid metal 42. In particular, an amorphous film has no crystal grain boundaries, and therefore effectively prevents erosion by the liquid metal 42. This allows the reflective member 411 to protect the reflective layer 413 and thereby maintain stable reflection characteristics for a long period of time.

[0054] In this embodiment, the wavelength conversion element 41 is configured to emit fluorescence YL obtained by wavelength-converting light rays BLs incident from the upper surface 410b of the phosphor layer 410 from the upper surface 410b of the phosphor layer 410. That is, the upper surface 410b of the phosphor layer 410 corresponds to a light exit surface 41a of the wavelength conversion element 41. Note that the light exit surface 41a of the wavelength conversion element 41 also serves as a light entrance surface onto which light rays BLs emitted from the first focusing optical system 26 are incident.

[0055] The liquid metal 42 is disposed in the gap between the substrate 40 and the rear surface 41b (surface of the reflecting member 411) of the wavelength conversion element 41. In this embodiment, the volume of the liquid metal 42 is set to be smaller (for example, 60% to 99%) than the volume of the gap between the substrate 40 and the wavelength conversion element 41. By making the volume of the liquid metal 42 smaller than the volume of the gap in this way, even if deformation or expansion of the liquid metal 42 occurs due to heat, the pressure of the liquid metal 42 does not increase in the gap, and leakage of the liquid metal 42 can be prevented.

[0056] The liquid metal 42 transfers the heat generated in the phosphor layer 410 to the substrate 40, thereby cooling it. As the liquid metal 42, for example, one or more low-melting-point metals selected from the group consisting of Ga (melting point: 29.8°C, thermal conductivity: 40.6 W / mK), In (melting point: 156.4°C, thermal conductivity: 81.6 W / mK), and Sn (melting point: 231.97°C, thermal conductivity: 66.6 W / mK), or an alloy containing one or more low-melting-point metals can be used. Specific examples of alloys include In-Ag, Sn-Ag-Cu, In-Sn-Bi, Ga-In-Sn-Zn, Ga-In-Sn, and Ga-In.

[0058] The first restricting portion 43 holds the wavelength conversion element 41 on the base material 40 and restricts the position of the wavelength conversion element 41 in an optical axis direction (first direction) 41C along a normal 41H to the light exit surface 41a. The optical axis direction 41C is a direction along the chief ray of the fluorescence YL emitted from the light exit surface 41a, and is a direction along the illumination optical axis ax2 of the light source device 2. Here, the position of the wavelength conversion element 41 in the optical axis direction 41C is restricted means that the distance between the upper surface 410b of the phosphor layer 410 and the first light-collecting optical system 26 does not change in the optical axis direction 41C.

[0059] In this embodiment, the first restricting portion 43 has a sealing member 43a that seals the liquid metal 42 between the substrate 40 and the wavelength conversion element 41. The first restricting portion 43 in this embodiment is arranged to surround the periphery of the wavelength conversion element 41 in a frame shape. The first restricting portion 43 is formed, for example, by applying and curing a highly heat-resistant silicone adhesive. In this embodiment, the first restricting portion 43 is arranged over an outer edge 44 of the light emitting surface 41a of the wavelength conversion element 41, a side surface 45 of the wavelength conversion element 41 (phosphor layer 410) that intersects with the light emitting surface 41a, and a part of the first surface 40a of the substrate 40. This allows the wavelength conversion element 41 to be held on the first surface 40a of the substrate 40.

[0060] The wavelength conversion device 4 according to the present embodiment described above provides the following effects. The wavelength conversion device 4 of this embodiment comprises a substrate 40, a wavelength conversion element 41 having a phosphor layer 410 and a reflective member 411, a liquid metal 42 arranged between the substrate 40 and the phosphor layer 410, and a first regulating portion 43 that regulates the position of an optical axis direction 41C along a normal 41H of the light emission surface 41a of the wavelength conversion element 41.

[0061] According to the wavelength conversion device 4 of this embodiment, when the temperature of the phosphor layer 410 rises, even if there is a difference in the expansion coefficient between the phosphor layer 410 and the substrate 40, no stress is generated inside the liquid metal 42, thereby preventing the phosphor layer 410 from suffering from thermal stress, which can cause damage or peeling. Furthermore, since the first restricting portion 43 keeps the liquid metal 42 in contact with both the wavelength conversion element 41 and the base material 40, heat generated in the phosphor layer 410 of the wavelength conversion element 41 is efficiently dissipated by being transferred to the base material 40 via the liquid metal 42. This improves the cooling efficiency of the phosphor layer 410, thereby enabling the generation of bright fluorescence YL. Furthermore, even if the temperature of the wavelength conversion element 41 rises, the first restricting portion 43 keeps the distance between the light exit surface 41a of the wavelength conversion element 41 and the first focusing optical system 26 substantially constant, so that the spot size of the excitation light (light beams BLs) formed on the phosphor layer 410 does not change, thereby making it possible to keep the light density of the phosphor layer 410 constant. Furthermore, the amount of fluorescence YL emitted from the phosphor layer 410 taken up by the first focusing optical system 26 can be kept constant. In other words, by providing the first restricting portion 43, it is possible to stably generate fluorescence YL in the phosphor layer 410 and efficiently take in and utilize the generated fluorescence YL.

[0062] In this embodiment, the first restricting portion 43 has a sealing member 43a that seals the liquid metal 42 between the substrate 40 and the wavelength conversion element 41.

[0063] This configuration can prevent the liquid metal 42 from leaking from the gap between the wavelength conversion element 41 and the substrate 40. Furthermore, even if there is a difference in the expansion coefficient between the phosphor layer 410 and the substrate 40, the sealing member 43a deforms slightly, so that stress is not generated in the phosphor layer 410. Therefore, it is possible to prevent problems such as breakage or peeling due to thermal stress generated in the phosphor layer 410.

[0064] In this embodiment, the first restricting portion 43 is disposed to cover the outer edge 44 of the light exit surface 41 a of the wavelength conversion element 41 and the side surface 45 of the wavelength conversion element 41 .

[0065] According to this configuration, the area sealed by the first restricting portion 43 is increased, which can further suppress leakage of the liquid metal 42 from between the wavelength conversion element 41 and the substrate 40. In addition, the bonding strength between the wavelength conversion element 41 and the substrate 40 can be increased.

[0066] In this embodiment, the wavelength conversion element 41 has a phosphor layer 410 and a reflecting member 411 , and the reflecting member 411 has a multilayer structure including a reflecting layer 413 and a protective layer 414 that protects the reflecting layer 413 .

[0067] Here, if the liquid metal 42 comes into contact with the reflective layer 413 made of Ag or Al, it may corrode the crystal grain boundaries, causing a decrease in reflectivity. In contrast, in the present embodiment, the reflective layer 413 is protected by the protective layer 414, so that the reflective layer 413 can be protected from the erosion by the liquid metal 42.

[0068] In this embodiment, the substrate 40 is formed as a vapor chamber. The base material 40 made of a vapor chamber has high thermal conductivity and excellent heat dissipation properties, and can therefore efficiently cool the wavelength conversion element 41. Therefore, the wavelength conversion element 41 can be irradiated with the excitation light beam BLs at a stronger intensity, and brighter illumination light WL can be generated.

[0069] The light source device 2 of this embodiment includes a wavelength converter 4 and a light source 21 that emits a light beam BLs toward the wavelength converter 4.

[0070] The light source device 2 of this embodiment is equipped with a wavelength conversion device 4 that suppresses damage and peeling of the wavelength conversion element 41, has high light utilization efficiency, and can efficiently cool the wavelength conversion element 41, so it is possible to generate highly reliable and bright illumination light WL.

[0071] The projector 1 of this embodiment includes a light source device 2, light modulation devices 11R, 11G, and 11B that modulate the light emitted from the light source device 2 according to image information, and a projection optical device 6 that projects the light modulated by the light modulation devices 11R, 11G, and 11B.

[0072] The projector 1 of this embodiment is highly reliable and includes the light source device 2 that generates bright illumination light WL, so that it can project bright images for a long period of time.

[0073] (First Modification) Next, a wavelength conversion device according to a first modification will be described. The difference between this modification and the first embodiment is that a recess is provided in the substrate, and the other configurations are the same. Therefore, the same symbols are used for the configurations that are common to the first embodiment, and detailed descriptions will be omitted.

[0074] FIG. 5 is a cross-sectional view showing the configuration of a wavelength converter according to this modified example. As shown in Fig. 5, in the wavelength converter 4A of this modified example, a recess (first recess) 47 is formed on the first surface 40a of the substrate 40. The depth of the recess 47 is set to, for example, 5 µm to 100 µm. The plane area of the recess 47 is smaller than the plane area of the wavelength conversion element 41 (phosphor layer 410). Therefore, a gap is formed between the back surface 410a of the phosphor layer 410 and the substrate 40 in a portion facing the recess 47, and the back surface 410a of the phosphor layer 410 is in contact with the substrate 40 in a portion not facing the recess 47.

[0075] Liquid metal 42 is placed in recess 47. The volume of liquid metal 42 is set to be smaller (for example, 60% to 99%) than the volume of recess 47. By making the volume of liquid metal 42 smaller than the volume of recess 47, the pressure of liquid metal 42 does not increase within recess 47 even if deformation or expansion of liquid metal 42 occurs due to heat, and leakage of liquid metal 42 can be prevented.

[0076] In this modification, the entire liquid metal 42 is disposed in the recess 47, but a part of the liquid metal 42 may be disposed in the recess 47, and the remaining part of the liquid metal 42 may be disposed between the first surface 40a of the substrate 40 and the back surface 41b of the wavelength conversion element 41 (the surface of the reflecting member 411). Also, in this modification, the recess 47 is formed on the first surface 40a of the substrate 40, but the recess 47 may be formed on the back surface 41b of the wavelength conversion element 41. Furthermore, the recess 47 may be formed on both the first surface 40a of the substrate 40 and the back surface 41b of the wavelength conversion element 41. In other words, the recess 47 is formed on at least one of the substrate 40 and the wavelength conversion element 41.

[0077] According to the wavelength conversion device 4A of this modified example, liquid metal 42 is placed in a recess 47 formed on the first surface 40a of the substrate 40, and the first surface 40a of the substrate 40 comes into contact with the back surface 41b of the wavelength conversion element 41 in the area surrounding the outer periphery of the recess 47, thereby blocking the gap and preventing the liquid metal 42 from leaking to the outside.

[0078] Second Embodiment Next, a wavelength conversion device according to a second embodiment will be described. This embodiment and the first embodiment differ in the configuration of the first restricting portion and the substrate, but the other configurations are common. Therefore, the following description will mainly focus on the first restricting portion and its peripheral configuration, and the same reference numerals will be used for the configurations and members common to the first embodiment, and their details will be omitted or simplified.

[0079] FIG. 6A is a cross-sectional view showing the configuration of a wavelength converter of this embodiment, and FIG. 6B is a perspective view showing the configuration of a wavelength converter of this embodiment. As shown in FIGS. 6A and 6B, the wavelength converter 104 of this embodiment includes a substrate 40, a wavelength conversion element 41, a liquid metal 42, a first restricting portion 143, and a second restricting portion 50. In this embodiment, as shown in FIG. 6A, recesses 47 are formed on the first surface 40a of the substrate 40, as in the first modified example, and the liquid metal 42 is disposed in the recesses 47.

[0080] The first restricting portion 143 of this embodiment has a pair of leaf springs (elastic members) 143a that press the wavelength conversion element 41 toward the base material 40. The pair of leaf springs 143a press portions of the upper surface 410b of the phosphor layer 410 that do not overlap with the recessed portion 47 in plan view. This configuration can prevent cracks from occurring due to deformation of the phosphor layer 410 by the elastic force of the leaf springs 143a.

[0081] The second restricting portion 50 has a pair of pins 50a provided on the first surface 40a of the substrate 40. The pair of pins 50a are arranged with a gap between them. The gap between the pair of pins 50a corresponds to one width of the wavelength conversion element 41. Therefore, the pair of pins 50a sandwich the wavelength conversion element 41, thereby restricting the position of the wavelength conversion element 41 in a width direction (second direction) 41D perpendicular to the optical axis direction 41C. In this embodiment, the pair of pins 50a regulate the position of the wavelength conversion element 41 in the width direction 41D where the position regulation by the pair of leaf springs 143a is insufficient. As a result, the wavelength conversion element 41 is well held on the substrate 40 with its position regulated by the first regulating portion 143 and the second regulating portion 50.

[0082] According to the wavelength converter 104 of the present embodiment, even if there is a difference in the expansion coefficient between the phosphor layer 410 and the base material 40, the first restricting portion 143 having the leaf spring 143a elastically deforms, so that stress is not generated in the phosphor layer 410. Therefore, damage or peeling caused by stress generated in the phosphor layer 410 can be suppressed.

[0083] (Second Modification) Next, a wavelength conversion device according to a second modification will be described. This modification relates to a configuration in which the configuration of the first modification and the leaf spring of the second embodiment are combined. FIG. 7 is a cross-sectional view showing the configuration of a wavelength converter according to this modified example. As shown in FIG. 7, a wavelength converter 104A of this modified example includes a substrate 40, a wavelength conversion element 41, a liquid metal 42, and a first restricting portion 243.

[0084] The first restricting portion 243 of this modified example includes a sealing member 43a and a pair of leaf springs 143a. According to the wavelength converter 104A of this modification, the first restricting portion 243 has both the sealing member 43a and the pair of leaf springs 143a, and therefore, the elastic force of the leaf springs 143a can stably hold the phosphor layer 410 on the base material 40 while preventing leakage of the liquid metal 42. Therefore, it is possible to prevent a decrease in light utilization efficiency due to a change in the distance between the upper surface 410b of the phosphor layer 410 and the first collecting optical system 26.

[0085] (Third embodiment) Next, a wavelength conversion device according to a third embodiment will be described. This embodiment differs from the wavelength conversion device 4 of the first embodiment in that it includes a frame disposed between the substrate 40 and the wavelength conversion element 41, but the other configurations are the same. In the following description, the same reference numerals are used to designate the same configurations and members as those of the first embodiment, and their details will be omitted or simplified.

[0086] FIG. 8A is an exploded perspective view showing the configuration of the wavelength converter of this embodiment, and FIG. 8B is a cross-sectional view showing the configuration of the wavelength converter of this embodiment. As shown in FIGS. 8A and 8B, a wavelength converter 204 of this embodiment includes a substrate 40, a wavelength conversion element 41, a liquid metal 42, a first restricting portion 43, and a frame 51. In this embodiment, the frame 51 is held in a state sandwiched between the first surface 40a of the substrate 40 and the surface of the reflecting member 411 of the wavelength conversion element 41. The liquid metal 42 is disposed in a region surrounded by the substrate 40, the wavelength conversion element 41, and the frame 51.

[0087] The frame 51 is made of, for example, metal such as stainless steel or copper, resin, rubber, etc., and by using rubber, the gap between the substrate 40 and the wavelength conversion element 41 can be sealed, thereby preventing leakage of the liquid metal 42.

[0088] According to the wavelength converter 204 of this embodiment, by providing the frame 51, it is possible to realize a configuration that prevents leakage of the liquid metal 42 without forming recesses on the surface of the substrate 40 or the wavelength conversion element 41.

[0089] In the present embodiment, the outside of the frame 51 is sealed by the first restricting portion 43, which can further enhance the effect of preventing leakage of the liquid metal 42. The first restricting portion 43 may be replaced with a first restricting portion 143 having a pair of leaf springs 143a. Furthermore, as in the second modified example, the wavelength conversion element 41 may be held on the substrate 40 using a first restricting portion 243 having a leaf spring 143a and a sealing member 43a.

[0090] (Fourth embodiment) Next, a wavelength conversion device according to a fourth embodiment will be described. This embodiment differs significantly from the wavelength conversion device 4 of the first embodiment in that a capillary force generating member is provided between the substrate 40 and the wavelength conversion element 41. In the following description, the same reference numerals are used to designate the same components and members as those of the first embodiment, and their details will be omitted or simplified.

[0091] FIG. 9 is a cross-sectional view showing the configuration of the wavelength converter of this embodiment. As shown in FIG. 9, a wavelength converter 304 of this embodiment includes a substrate 40, a wavelength conversion element 41, a liquid metal 42, a first restricting portion 43, and a capillary force generating portion (holding portion) 52. In this embodiment, the capillary force generating unit 52 is held in a state sandwiched between the first surface 40a of the substrate 40 and the back surface 41b (surface of the reflecting member 411) of the wavelength conversion element 41. The capillary force generating unit 52 generates a capillary force that holds the liquid metal 42. The capillary force generating unit 52 is formed, for example, from a mesh woven from thin wires having a diameter of several tens of μm or from a thin plate etched into a mesh shape.

[0092] The first restricting portion 43 may be replaced with a first restricting portion 143 having a pair of leaf springs 143a. Also, as in the second modified example, the wavelength conversion element 41 may be held on the substrate 40 using a first restricting portion 243 having a leaf spring 143a and a sealing member 43a.

[0093] According to the wavelength converter 304 of this embodiment, by providing the capillary force generating unit 52, the liquid metal 42 can be well retained between the base material 40 and the wavelength conversion element 41. Specifically, by arranging the capillary force generating unit 52 directly below the light-emitting region of the wavelength conversion element 41 (phosphor layer 410) which generates the most heat, the liquid metal 42 can be reliably present directly below the light-emitting region which generates the most heat, regardless of the installation orientation of the light source device 2 including the wavelength converter 4 (wavelength conversion element 41). Therefore, by providing the wavelength converter 304 of this embodiment, a light source device with higher heat dissipation properties can be realized.

[0094] In the present embodiment, the capillary force generating unit 52 is configured from a mesh-like member, but it may be formed on the surface of the substrate 40 facing the wavelength conversion element 41, like a capillary force generating unit (holding unit) 152 shown in Fig. 10. In this case, the capillary force generating unit 152 is formed on the first surface 40a of the substrate 40, and is configured from fine grooves or a grid.

[0095] (Third Modification) Next, a wavelength conversion device according to a third modified example will be described. This modified example relates to a configuration in which the frame of the third embodiment is combined with the capillary force generating member of the fourth embodiment. FIG. 11 is an exploded perspective view showing the configuration of a wavelength converter according to this modified example. 11, a wavelength conversion device 304A of this modified example includes a substrate 40, a wavelength conversion element 41, a liquid metal 42, a first restriction portion 43, a frame 51, and a capillary force generating portion 52. The thickness of the frame 51 is greater than the thickness of the capillary force generating portion 52. The capillary force generating portion 52 is disposed in a region surrounded by the frame 51. In FIG. 11, the liquid metal 42 is permeated into and held in the capillary force generating portion 52.

[0096] According to the wavelength conversion device 304A of this modified example, the capillary force generating section 52 is provided in the area surrounded by the frame body 51, so that the frame body 51 prevents the liquid metal 42 from leaking out to the outside, and the capillary force generating section 52 can provide a light source device with excellent heat dissipation properties.

[0097] Fifth Embodiment Next, a wavelength conversion device according to a fifth embodiment will be described. This embodiment differs significantly from the other embodiments and modifications in that the wavelength conversion element 41 is disposed in a recess formed in the substrate. In the following description, the same reference numerals are used to designate the same components and members as those in the first embodiment, and their details will be omitted or simplified.

[0098] FIG. 12 is a cross-sectional view showing the configuration of the wavelength converter of this embodiment. As shown in FIG. 12, a wavelength converter 404 of this embodiment includes a substrate 40, a wavelength conversion element 41, a liquid metal 42, and a first restricting portion 143. In this embodiment, the wavelength conversion element 41 is disposed in a recess (second recess) 147 formed in the first surface 40a of the substrate 40. The upper surface (light exit surface 41a) of the wavelength conversion element 41 is disposed flush with the first surface 40a of the substrate 40. The first restricting portion 443 (a pair of leaf springs 143a) is provided so as to straddle the light exit surface 41a of the wavelength conversion element 41 and the first surface 40a.

[0099] A recess (first recess) 148 is formed on a bottom surface 147a of the recess 147. The depth of the recess 148 is set to, for example, 5 μm to 100 μm. The recess 148 is a recess when viewed from the optical axis direction 41C. 147 The planar area of the recess 148 is smaller than the planar area of the wavelength conversion element 41 (phosphor layer 410). Therefore, the rear surface 41b of the wavelength conversion element 41 has a gap between it and the base material 40 in the portion facing the recess 148, and the recess 148 The portion of the liquid metal 42 that does not face the recess 148 is in contact with the bottom surface 147a of the recess 147. In this embodiment, the liquid metal 42 is disposed in the recess 148. The volume of the liquid metal 42 is set to be smaller than the volume of the recess 148 (for example, 60% to 99%).

[0100] According to the wavelength conversion device 404 of this embodiment, the wavelength conversion element 41 is disposed in the recess 147 formed in the substrate 40, so that the contact area between the wavelength conversion element 41 and the substrate 40 can be increased. As a result, heat is efficiently transferred from the wavelength conversion element 41 to the substrate 40, so that the cooling performance of the wavelength conversion element 41 can be improved. Therefore, the wavelength conversion element 41 can generate brighter illumination light WL.

[0101] 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. Furthermore, one aspect of the present invention can be a configuration in which the characteristic portions of the above-described embodiments are appropriately combined.

[0102] In addition, the specific descriptions of the shape, number, arrangement, materials, etc. of each component of the light source device and the projector are not limited to the above-described embodiments and can be modified as appropriate. Furthermore, in the above-described embodiments, an example was shown in which the light source device according to the present invention was mounted in a projector using a liquid crystal panel, but this is not limiting. The light source device according to the present invention may also be applied to a projector using a digital micromirror device as a light modulation device. Furthermore, the projector does not need to have multiple light modulation devices, and may have only one light modulation device.

[0103] In the above embodiment, the light source device of the present invention is applied to a projector, but the present invention is not limited to this. The light source device of the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

[0104] A wavelength conversion device according to one aspect of the present invention may have the following configuration. A wavelength conversion device according to one embodiment of the present invention comprises a substrate having a first surface, a wavelength conversion element disposed on the side of the first surface of the substrate, which converts first light in a first wavelength band into second light in a second wavelength band different from the first wavelength band, and which has a light exit surface disposed on the opposite side of the substrate and which emits the second light, a liquid metal disposed between the substrate and the wavelength conversion element, and a first regulating portion which holds the wavelength conversion element on the substrate and regulates the position of the wavelength conversion element in a first direction normal to the light exit surface.

[0105] In the wavelength converter according to one aspect of the present invention, the first restricting portion may have a sealing member that seals the liquid metal between the substrate and the wavelength conversion element.

[0106] In one aspect of the wavelength conversion device of the present invention, the sealing member may be configured to be arranged over the outer edge of the light exit surface of the wavelength conversion element, a side surface of the wavelength conversion element that intersects with the light exit surface, and a portion of the first surface of the substrate.

[0107] In the wavelength converter according to one aspect of the present invention, the first restricting portion may have an elastic member that presses the wavelength conversion element toward the substrate.

[0108] The wavelength converter according to one aspect of the present invention may further include a second restricting portion that restricts the position of the wavelength conversion element in a second direction perpendicular to the first direction.

[0109] In the wavelength conversion device according to one aspect of the present invention, at least a part of the liquid metal may be disposed in a first recess formed in at least one of the substrate and the wavelength conversion element.

[0110] In one aspect of the wavelength conversion device of the present invention, the substrate may have the first recess and a second recess having a planar area smaller than the planar area of the first recess when viewed from the first direction, the first recess may be formed on the bottom surface of the second recess, the liquid metal may be disposed in the first recess, and the wavelength conversion element may be disposed in the second recess.

[0111] In the wavelength converter according to one aspect of the present invention, the planar area of the first recess may be smaller than the planar area of the wavelength conversion element when viewed from the first direction.

[0112] In one aspect of the wavelength conversion device of the present invention, the wavelength conversion device may further include a frame body arranged between the substrate and the wavelength conversion element, and the liquid metal may be arranged in an area surrounded by the substrate, the wavelength conversion element, and the frame body.

[0113] The wavelength conversion device according to one aspect of the present invention may further include a holding portion disposed between the substrate and the wavelength conversion element, the holding portion generating a capillary force that holds the liquid metal.

[0114] In the wavelength conversion device according to one aspect of the present invention, the holding portion may be formed on a surface of the base material facing the wavelength conversion element.

[0115] In one aspect of the wavelength conversion device of the present invention, the wavelength conversion element may have a wavelength conversion layer that converts the first light to the second light, and a reflective member that is provided on the surface of the wavelength conversion layer facing the substrate and reflects the first light and the second light, and the reflective member may have a multilayer structure that includes a reflective layer and a protective layer that is arranged on the liquid metal side of the reflective layer.

[0116] In the wavelength conversion device according to one aspect of the present invention, the substrate may be a vapor chamber.

[0117] 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 the wavelength conversion device described above, into which the first light emitted from the light source is incident.

[0118] A projector according to one aspect of the invention may have the following configuration. A projector according to one aspect of the present invention comprises a light source device according to one aspect of the present invention, an optical modulation device that modulates light emitted from the light source device in accordance with image information, and a projection optical device that projects the light modulated by the optical modulation device. [Explanation of symbols]

[0119] 1...projector, 2...light source device, 4, 4A, 104, 104A, 204, 304, 304A, 404...wavelength conversion device, 6...projection optical device, 11B, 11G, 11R...light modulation device, 21...light source, 40...substrate, 40a...first surface, 41...wavelength conversion element, 41a...light exit surface, 41C...optical axis direction (first direction), 41D...width direction (second direction), 41H...normal, 42...liquid metal, 43, 143, 243, 443...first Regulating portion, 43a...sealing member, 44...outer edge, 45...side surface, 47, 148...recess (first recess), 50...second restricting portion, 51...frame body, 52, 152...capillary force generating portion (holding portion), 143a...plate spring (elastic member), 147...recess (second recess), 147a...bottom surface, 410...phosphor layer (wavelength conversion layer), 411...reflective member, 413...reflective layer, 414...protective layer, 500...wavelength, BL...blue light beam (first light), YL...fluorescence (second light).

Claims

1. a substrate having a first surface; a wavelength conversion element disposed on the first surface side of the substrate, converting first light in a first wavelength band into second light in a second wavelength band different from the first wavelength band, and having a light exit surface provided on the opposite side to the substrate and exiting the second light; a liquid metal disposed between the substrate and the wavelength conversion element and liquid at room temperature; a first restricting portion that holds the wavelength conversion element on the base and restricts a position of the wavelength conversion element in a first direction along a normal to the light exit surface, the substrate has a first recess in which the liquid metal is disposed; a plane area of the first recess is smaller than a plane area of the wavelength conversion element when viewed from the first direction; the volume of the liquid metal is less than the volume of the first recess; A wavelength conversion device characterized by:

2. the first restricting portion has a sealing member that seals the liquid metal between the base material and the wavelength conversion element; 2. The wavelength conversion device according to claim 1.

3. the sealing member is disposed over an outer edge of the light exit surface of the wavelength conversion element, a side surface of the wavelength conversion element intersecting the light exit surface, and a part of the first surface of the base material.

3. The wavelength conversion device according to claim 2.

4. the first restricting portion has an elastic member that presses the wavelength conversion element toward the base material; 4. The wavelength conversion device according to claim 1, wherein the wavelength conversion element is a reflective layer.

5. a second restricting portion that restricts the position of the wavelength conversion element in a second direction perpendicular to the first direction; 5. The wavelength conversion device according to claim 4.

6. the substrate further has a second recess having a planar area larger than a planar area of the first recess when viewed from the first direction, the first recess is formed on a bottom surface of the second recess, the liquid metal is disposed in the first recess; The wavelength conversion element is disposed in the second recess.

6. The wavelength conversion device according to claim 1, wherein the wavelength conversion element is a reflective layer.

7. the wavelength conversion element includes a wavelength conversion layer that converts the first light into the second light, and a reflecting member that is provided on a surface of the wavelength conversion layer facing the base and that reflects the first light and the second light, The reflective member has a multilayer structure including a reflective layer and a protective layer disposed on the liquid metal side of the reflective layer.

7. The wavelength conversion device according to claim 1, wherein the wavelength conversion element is a reflective layer.

8. The substrate is a vapor chamber.

8. The wavelength conversion device according to claim 1, wherein the wavelength conversion element is a reflective layer.

9. a light source that emits the first light; a wavelength conversion device according to claim 1 , into which the first light emitted from the light source is incident, A light source device characterized by:

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

Images