Wavelength conversion device, light source device, projector, and method of manufacturing wavelength conversion device

Abstract

To provide a wavelength conversion device capable of suppressing corrosion of a substrate, a light source device, a projector, and a method of manufacturing the wavelength conversion device.SOLUTION: A wavelength conversion device includes: a base material made by one of copper and copper alloy; a bonding film disposed on a first surface of the base material; a bonding material disposed on the bonding film; a wavelength conversion element disposed on the bonding material; and an oxide film formed on an entire surface of the base material on which the bonding film is not present.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a wavelength conversion device, a light source device, a projector, and a method for manufacturing a wavelength conversion device. [Background technology]

[0002] Conventionally, there is known a projector that includes an illumination device that emits illumination light, a color separation optical system that separates red light, green light, and blue light from the illumination light, three light modulation devices that modulate each of the separated color lights, a synthesis optical system that synthesizes each of the modulated color lights, and a projection optical device that projects the synthesized image light (see, for example, Patent Document 1). The illumination device of the projector described in Patent Document 1 includes a first light source unit that emits excitation light having a first wavelength band, and a wavelength conversion element that converts the incident excitation light into fluorescence having a second wavelength band different from the first wavelength band. The wavelength conversion element includes a wavelength conversion layer, a first substrate, a first intermediate layer, a second substrate, a second intermediate layer, and a second substrate, which are stacked in this order from the side where excitation light is incident.

[0003] The first substrate is made of a ceramic heat dissipation substrate. The first intermediate layer is provided between the wavelength conversion layer and the first substrate. The first intermediate layer is composed of a first bonding layer provided on the first surface of the wavelength conversion layer and a second bonding layer provided on the first substrate. Each of the first bonding layer and the second bonding layer is composed of a siloxane compound having high light transmittance. The wavelength conversion layer receives excitation light and emits fluorescent light, and includes a phosphor layer, a total reflection layer, an enhanced reflection layer, a first deterioration prevention layer, a reflection layer, and a second deterioration prevention layer. The second intermediate layer is composed of a silver layer and a nanosilver layer, and bonds the second substrate and the wavelength conversion layer. The second substrate is made of a metal heat dissipation substrate made of, for example, copper. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-144163 A Summary of the Invention [Problem to be solved by the invention]

[0005] The second substrate described in Patent Document 1 is a copper substrate made of copper. Copper substrates have the property of being easily corroded by sulfur and chlorine. When the copper substrate corrodes, metal pieces may be generated, and such metal pieces may affect surrounding members. For example, when metal pieces are generated inside a projector that projects image light and adhere to optical components, this causes a decrease in the brightness of the projected image light. For this reason, a structure capable of suppressing corrosion of the substrate has been desired. [Means for solving the problem]

[0006] A wavelength conversion device according to a first aspect of the present disclosure includes a substrate made of either copper or a copper alloy, a bonding film disposed on a first surface of the substrate, a bonding material disposed on the bonding film, a wavelength conversion element disposed on the bonding material, and an oxide film formed on all surfaces of the substrate where the bonding film is not present.

[0007] A light source device according to a second aspect of the present disclosure includes a solid-state light source that emits excitation light, and the wavelength conversion device according to the first aspect that converts the wavelength of the excitation light.

[0008] A projector according to a third aspect of the present disclosure includes the light source device according to the second aspect described above, an image light generation device that generates image light from light from the light source device, and a projection optical device that projects the generated image light.

[0009] A manufacturing method for a wavelength conversion device according to a fourth aspect of the present disclosure includes forming a bonding film on a first surface of a base material made of either copper or a copper alloy, placing a bonding material on the bonding film, placing a wavelength conversion element on the bonding material, fixing the bonding material by heat treatment, and forming an oxide film on all surfaces of the base material where the bonding film is not present. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a projector according to a first embodiment. [Diagram 2] FIG. 1 is a schematic diagram showing a configuration of a light source device according to a first embodiment. [Diagram 3] FIG. 1 is a cross-sectional view showing a wavelength converter according to a first embodiment. [Figure 4] 4 is a flowchart showing a manufacturing process of the wavelength converter in the first embodiment. [Diagram 5] FIG. 11 is a cross-sectional view showing a wavelength converter according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [First embodiment] Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings. [Projector configuration] FIG. 1 is a schematic diagram showing the configuration of a projector 1 according to the present embodiment. A projector 1 according to this embodiment projects image light according to image information. As shown in Fig. 1, the projector 1 includes an exterior housing 2 and an image projection device 3 housed in the exterior housing 2. In addition, although not shown, the projector 1 includes a control device that controls the operation of the projector 1, a power supply device that supplies power to electronic components of the projector 1, and a cooling device that cools a cooling target of the projector 1.

[0012] [Exterior casing configuration] The exterior housing 2 has a front portion 21, a rear portion 22, a left side portion 23, a right side portion 24, and a top surface and a bottom surface (not shown), and is formed into a generally rectangular parallelepiped shape. The front portion 21 and the back portion 22 constitute opposite surfaces of the exterior housing 2. The front portion 21 has an opening for exposing an end portion on the light emission side of a projection optical device 36 described later. The left side surface portion 23 and the right side surface portion 24 constitute surfaces that are opposite to each other in the exterior housing 2. The top surface portion and the bottom surface portion constitute surfaces that are opposite to each other in the exterior housing 2. In the following description, the three mutually orthogonal directions are defined as the +X direction, the +Y direction, and the +Z direction. Furthermore, the +Z direction is defined as the direction from the rear portion 22 toward the front portion 21, the +X direction is defined as the direction from the right side portion 24 toward the left side portion 23, and the +Y direction is defined as the direction from the bottom portion toward the top portion. Although not shown in the figures, the direction opposite to the +X direction is defined as the -X direction, the direction opposite to the +Y direction is defined as the -Y direction, and the direction opposite to the +Z direction is defined as the -Z direction. The axis along the +X direction is defined as the X axis, the axis along the +Y direction is defined as the Y axis, and the axis along the +Z direction is defined as the Z axis.

[0013] [Configuration of image projection device] The image projection device 3 forms image light according to input image information and projects the formed image light. The image projection device 3 includes a light source device 4, an image light generation device 30, and a projection optical device . The light source device 4 emits illumination light to the homogenizing optical system 31 of the image light generating device 30. The configuration of the light source device 4 will be described in detail later.

[0014] The image light generation device 30 generates image light from the illumination light emitted from the light source device 4. The image light generation device 30 has a homogenization optical system 31, a color separation optical system 32, a relay optical system 33, a light modulation device 34, and an optical component housing 35. The homogenizing optical system 31 homogenizes the illumination light emitted from the light source device 4. The homogenized illumination light passes through a color separation optical system 32 and a relay optical system 33, and illuminates a modulation area of ​​a light modulation element 343 (described later). The homogenizing optical system 31 includes two lens arrays 311 and 312, a polarization conversion element 313, and a superimposing lens 314. The color separation optical system 32 separates the illumination light incident from the homogenization optical system 31 into red, green, and blue color lights. The color separation optical system 32 includes two dichroic mirrors 321 and 323, a reflecting mirror 322 that reflects the blue light separated by the dichroic mirror 321, a lens 324 disposed between the dichroic mirror 321 and the reflecting mirror 322, and a lens 325 disposed between the dichroic mirrors 321 and 323.

[0015] Relay optical system 33 is provided on the optical path of red light which is longer than the optical paths of the other colored lights, and suppresses loss of red light. Relay optical system 33 includes an incident side lens 331, a relay lens 333, and reflecting mirrors 332 and 334. In this embodiment, red light is guided to relay optical system 33. However, this is not limiting, and for example, a configuration may be adopted in which blue light is the colored light having a longer optical path than the other colored lights, and the blue light is guided to relay optical system 33.

[0016] The light modulation device 34 modulates the incident red, green, and blue color lights, and combines the modulated color lights to form image light. The light modulation device 34 has three field lenses 341 provided according to the incident color lights, three incident-side polarizing plates 342, three light modulation elements 343, three exit-side polarizing plates 344, and one color combining optical system 345.

[0017] The light modulation elements 343 modulate the light from the light source device 4 to form image light. Specifically, the light modulation elements 343 modulate the color light incident from the incident-side polarizing plate 342 in accordance with an image signal, and emit the modulated color light. The three light modulation elements 343 include a light modulation element 343R that modulates red light, a light modulation element 343G that modulates green light, and a light modulation element 343B that modulates blue light. An example of the light modulation elements 343 is a transmissive liquid crystal panel.

[0018] The color synthesis optical system 345 synthesizes the three color lights modulated by the light modulation elements 343R, 343G, and 343B. The image light synthesized by the color synthesis optical system 345 is incident on the projection optical device 36. In this embodiment, the color synthesis optical system 345 is configured by a substantially rectangular parallelepiped cross dichroic prism, but may be configured by a plurality of dichroic mirrors.

[0019] The optical component housing 35 accommodates therein the homogenizing optical system 31, the color separation optical system 32, and the relay optical system 33. Note that the image projection device 3 is designed to have an optical axis Ax, and the optical component housing 35 holds the homogenizing optical system 31, the color separation optical system 32, the relay optical system 33, and the light modulation device 34 at predetermined positions on the optical axis Ax. The light source device 4, the light modulation device 34, and the projection optical device 36 are disposed at predetermined positions on the optical axis Ax. The projection optical device 36 projects the image light incident from the light modulation device 34 onto a projection surface such as a screen. That is, the projection optical device 36 projects the image light formed by the light modulation device 34. The projection optical device 36 can be, for example, a lens assembly including a plurality of lenses and a lens barrel that houses the plurality of lenses.

[0020] [Light source configuration] FIG. 2 is a schematic diagram showing the configuration of the light source device 4. As shown in FIG. The light source device 4 emits illumination light WL in the +X direction toward the homogenization optical system 31. As shown in Fig. 2, the light source device 4 includes a solid-state light source 41, a diffusion transmission section 42, a light separation section 43, a first light-collecting element 44, a wavelength conversion device 5, a second light-collecting element 45, a diffusion optical member 46, and a light source housing CA.

[0021] The light source device 4 has an optical axis Ax1 along the Z axis and an optical axis Ax2 along the X axis, the optical axes Ax1 and Ax2 being perpendicular to each other. The optical components of the light source device 4 are disposed on the optical axis Ax1 or the optical axis Ax2. Specifically, the solid-state light source 41, the diffuse transmission section 42, the light separating section 43, the first light collecting element 44, and the wavelength conversion device 5 are disposed on the optical axis Ax1. The diffusive optical member 46, the second light-collecting element 45, and the light separating section 43 are disposed on the optical axis Ax2. That is, the light separating section 43 is disposed at the intersection of the optical axis Ax1 and the optical axis Ax2. The optical axis Ax2 is connected to the optical axis Ax of the image projection device 3 by the lens array 311 of the uniformizing optical system 31.

[0022] [Solid-state light source configuration] The solid-state light source 41 emits light in the −Z direction. The solid-state light source 41 includes a light-emitting element 411 and a substrate 412. The light emitting element 411 emits blue light BL. The blue light BL is excitation light that excites the phosphor of the wavelength conversion device 5. The light emitting element 411 is, for example, a semiconductor laser that emits laser light with a peak wavelength of 455 nm. The substrate 412 is fixed to the inner surface of the light source casing CA while supporting the light emitting element 411. The substrate 412 receives heat from the light emitting element 411 and transfers the received heat to a heat dissipation member HD exposed to the outside of the light source casing CA.

[0023] [Configuration of diffuse transmission section] The diffuse transmission section 42 diffuses the blue light BL incident from the solid-state light source 41 and emits light with a uniform illuminance distribution. The blue light BL emitted from the diffuse transmission section 42 enters the light separation section 43. Examples of the diffuse transmission section 42 include a configuration having a hologram, a configuration in which a plurality of small lenses are arranged on a plane perpendicular to the optical axis, and a configuration in which the surface through which light passes is a rough surface. Note that a homogenizer optical element having a pair of multi-lens arrays may be used in the light source device 4 instead of the diffuse transmission section 42. On the other hand, when the diffuse transmission section 42 is used, the distance from the solid-state light source 41 to the light separation section 43 can be made shorter than when a homogenizer optical element is used.

[0024] [Structure of the light separation section] The light separating unit 43 has a function of a half mirror that transmits a part of the blue light BL and reflects the other blue light BL among the blue light BL incident from the solid-state light source 41 via the diffuse transmission unit 42. That is, the light separating unit 43 transmits a first partial light, which is a part of the blue light BL, among the blue light BL incident from the diffuse transmission unit 42, in the -Z direction to make it incident on the first light collecting element 44, and reflects a second partial light, which is the other blue light BL, in the -X direction to make it incident on the second light collecting element 45. The light separating unit 43 further functions as a dichroic mirror that reflects the fluorescence YL incident from the wavelength converter 5 in the +Z direction and transmits the blue light BL incident from the diffusing optical member 46 in the +X direction.

[0025] [Configuration of the first light-collecting element] The first light collecting element 44 collects the first partial light transmitted through the light separating unit 43 onto the wavelength conversion device 5. In addition, the first light collecting element 44 collimates the fluorescence YL incident from the wavelength conversion device 5 and causes the fluorescence YL to be incident on the light separating unit 43 along the +Z direction.

[0026] [Outline of wavelength conversion device] The wavelength converter 5 is a reflective wavelength conversion element that converts the wavelength of incident light, and diffuses the converted light in the opposite direction to the incident direction of the light and emits it. The converted light is, for example, non-polarized fluorescent light YL having a peak wavelength in the range of 500 to 700 nm, and the fluorescent light YL includes green light and red light. The configuration of the wavelength converter 5 will be described in detail later. The fluorescence YL emitted from the wavelength conversion device 5 passes through the first light collecting element 44 along the optical axis Ax1, and then enters the light separation unit 43. The fluorescence YL that enters the light separation unit 43 is reflected in the +X direction by the light separation unit 43, and is emitted to the outside of the light source device 4 along the optical axis Ax2.

[0027] [Configuration of the second light-collecting element] The second light collecting element 45 collects the second partial light incident from the light separating unit 43 onto the diffusing optical member 46. The second light collecting element 45 collimates the blue light incident from the diffusing optical member 46 and causes the light to enter the light separating unit 43 along the +Z direction.

[0028] [Configuration of diffusing optical components] The diffusing optical member 46 reflects and diffuses the blue light BL incident from the second light collecting element 45 at a diffusion angle substantially the same as the diffusion angle of the fluorescence YL emitted from the wavelength conversion device 5 or at a diffusion angle slightly smaller than the diffusion angle of the fluorescence YL. In other words, the diffusing optical member 46 reflects and diffuses the incident light without converting the wavelength of the incident light. The blue light BL reflected in the +X direction by the diffusing optical member 46 passes through the second light collecting element 45, then passes through the light separating unit 43 in the +X direction, and is emitted to the outside of the light source device 4 together with the fluorescent light YL. As described above, the illumination light WL emitted to the outside of the light source device 4 is white light that is a mixture of blue light BL and fluorescence YL containing green light and red light. The illumination light WL is emitted from the light source device 4 in the +X direction through the passage CA1 of the light source housing CA.

[0029] [Light source housing configuration] The light source housing CA is a housing for the light source device 4, and is one of the internal housings housed inside the exterior housing 2. The light source housing CA houses the solid light source 41, the diffuse transmission section 42, the light separation section 43, the first light collecting element 44, the wavelength conversion device 5, the second light collecting element 45, and the diffusion optical member 46. In this embodiment, the light source housing CA is a sealed housing into which dust is unlikely to enter. However, the light source housing CA is not limited to this and may be any housing capable of housing the above-mentioned optical components. The light source housing CA has a passage CA1. The passage CA1 is an opening through which the illumination light WL passes through the light source housing CA.

[0030] [Detailed configuration of wavelength conversion device] Fig. 3 is a diagram showing a cross section of the wavelength converter 5 along the XZ plane. That is, Fig. 3 is a diagram showing a cross section of the wavelength converter 5 along a plane defined by the -Z direction, which is the incident direction of blue light BL to the wavelength converter 5, and the +X direction perpendicular to the -Z direction. As described above, the wavelength converter 5 emits, in the +Z direction, fluorescence YL, which is converted light having a wavelength band longer than the wavelength band of the blue light BL incident along the -Z direction. As shown in Fig. 3, the wavelength converter 5 has a substrate 51, a bonding film 54, a bonding material 55, and a wavelength conversion element 56, as well as the heat dissipation member 57 shown in Fig. 2. In the wavelength converter 5, the wavelength conversion element 56, the bonding material 55, the bonding film 54, the substrate 51, and the heat dissipation member 57 are arranged in this order toward the -Z direction, which is the incident direction of the blue light BL.

[0031] [Board configuration] The substrate 51 is made of copper or a copper alloy. The substrate 51 supports a wavelength conversion element 56 that is bonded by a bonding film 54 and a bonding material 55. The substrate 51 has a base material 52 and an oxide film 53. The base material 52 is a plate-like body made of copper or a copper alloy. The base material 52 supports the wavelength conversion element 56 and also transfers heat transferred from the wavelength conversion element 56 to the heat dissipation member 57. The base material 52 may contain copper and copper alloy at a predetermined ratio or more, for example, 90% or more of copper or copper alloy in the composition of the base material 52. The base material 52 may contain impurities.

[0032] The base material 52 has a first surface 521 facing the +Z direction, a second surface 522 facing the -Z direction, a third surface 523 facing the +Y direction, and a fourth surface 524 facing the -Y direction. In addition, although not shown, the base material 52 has a fifth surface facing the +X direction and a sixth surface facing the -X direction. In the base material 52, the first surface 521 and the second surface 522 are surfaces opposite to each other, the third surface 523 and the fourth surface 524 are surfaces opposite to each other, and the fifth surface and the sixth surface are surfaces opposite to each other. The first surface 521 intersects with each of the third surface 523, the fourth surface 524, the fifth surface, and the sixth surface, and the second surface 522 intersects with each of the third surface 523, the fourth surface 524, the fifth surface, and the sixth surface.

[0033] On the first surface 521, a bonding film 54 is disposed. An oxide film 53 is formed on the entire surfaces of the second surface 522, the third surface 523, the fourth surface 524, the fifth surface, and the sixth surface in an oxide film forming step S4 described later. That is, the oxide film 53 is not a natural oxide film, but an artificial oxide film formed by a predetermined process. An example of the predetermined process is a process of heating to 200° C. in a thermostatic bath. The heating process may be performed after degreasing the base material 52 with alcohol, immersing it in a soft etching solution for a predetermined time, and drying the base material 52 with a dryer. 3, a heat dissipation member 57 is disposed on the second surface 522 so as to be capable of thermally conducting from the base material 52 via thermally conductive grease. The heat dissipation member 57 is exposed to the outside of the light source casing CA, and dissipates heat transferred from the base material 52 to the outside of the light source casing CA.

[0034] [Composition of bonding film] The bonding film 54 bonds the base material 52 and the wavelength conversion element 56 by being fixed to the bonding material 55. The bonding film 54 contains any of precious metals, such as silver (Ag), gold (Au), platinum (Pt), and palladium (Pd). More specifically, the bonding film 54 contains particles of the precious metal. In this embodiment, the bonding film 54 is a bonding film containing silver particles. The bonding film 54 is disposed on the first surface 521 of the base material 52. Specifically, the bonding film 54 is disposed on the entire surface of the first surface 521.

[0035] [Composition of bonding material] The bonding material 55 is disposed on the bonding film 54. That is, the bonding material 55 is disposed on the side of the bonding film 54 opposite to the base material 52 and in contact with the bonding film 54. The bonding material 55 and the bonding film 54 form a bonding layer. The bonding material 55 contains metal nanoparticles, more specifically, nanoparticles of a precious metal. In this embodiment, the bonding material 55 is made of a silver nanopaste containing silver nanoparticles. The bonding film 54 and the bonding material 55 are baked at, for example, 200° C. in an oxide film forming step S4 described later, whereby the silver particles of the bonding film 54 and the silver nanoparticles of the bonding material 55 are diffusion bonded by thermocompression bonding. As a result, the base material 52 and the wavelength conversion element 56 are bonded to each other.

[0036] [Configuration of wavelength conversion element] The wavelength conversion element 56 is provided at an end portion in the +Z direction into which the blue light BL is incident in the wavelength conversion device 5. The wavelength conversion element 56 has a reflective layer 561 and a phosphor layer 562. The reflective layer 561 is disposed on the opposite side of the bonding material 55 to the bonding film 54 so as to be in contact with the bonding material 55. That is, the reflective layer 561 is disposed on the base material 52 side of the wavelength conversion element 56. The reflective layer 561 reflects light incident from the phosphor layer 562 toward the phosphor layer 562. The reflective layer 561 can be formed of a multilayer film including a total reflection film. The phosphor layer 562 is laminated on the opposite side of the reflective layer 561 to the base material 52. That is, the phosphor layer 562 is laminated on the incident side of the reflective layer 561 for blue light BL. The phosphor layer 562 contains a phosphor that is excited by the incidence of the blue light BL. An example of the phosphor is a YAG:Ce phosphor that contains cerium as an activator. The blue light BL is directly incident on the phosphor layer 562 from the first light collecting element 44, and the phosphor layer 562 emits fluorescence YL in response to the incidence of the blue light BL.

[0037] [Manufacturing process of wavelength conversion device] FIG. 4 is a flowchart showing the manufacturing process of the wavelength converter 5. The above-mentioned wavelength converter 5 can be manufactured by the manufacturing process shown in FIG. 4, first, a bonding film forming step S1 is performed to form a bonding film 54 on the first surface 521 of the base material 52. When manufacturing the wavelength converter 5, the bonding film 54 is formed on the entire surface of the first surface 521. Next, a bonding material disposing step S2 is performed in which the bonding material 55 is disposed on the bonding film 54. In the bonding material disposing step S2, the bonding material 55 is laminated on the bonding film 54, and the bonding material 55 is disposed on the bonding film 54. Thereafter, a wavelength conversion element disposing step S3 is performed in which the wavelength conversion element 56 is disposed on the bonding material 55 on the side opposite to the bonding film 54. At this time, the wavelength conversion element 56 is disposed so that the reflective layer 561 contacts the bonding material 55.

[0038] Then, in the structure constructed through steps S1 to S3, an oxide film forming step S4 is performed in which the bonding film 54 and the bonding material 55 are fixed to each other and an oxide film 53 is formed on the base material 52. In the oxide film forming step S4, the structure is heated to 200° C. in a thermostatic chamber. As a result, the oxide film 53 is formed on all surfaces of the base material 52 except for the first surface 521 covered with the bonding film 54, and the bonding film 54 and the bonding material 55 are diffusion-bonded by thermocompression. By this process S4, an oxide film 53 is formed on the entire surface of each of the second surface 522, the third surface 523, the fourth surface 524, the fifth surface and the sixth surface, and the bonding film 54 and the bonding material 55 are fixed together, thereby fixing the wavelength conversion element 56 to the base material 52. Thereafter, a heat dissipation member arranging step S5 is performed in which a heat dissipation member 57 is arranged on the second surface 522 of the base material 52 via thermally conductive grease. Through these manufacturing steps, the wavelength converter 5 is manufactured.

[0039] [Comparison with natural oxide film] The present inventors have determined the progress of deterioration in a comparative substrate, which is substrate 52 on which an oxide film, which is a natural oxide film, is formed, and a target substrate, which is substrate 52 on which oxide film 53 is formed by the above-mentioned predetermined treatment. Specifically, the present inventors stored a comparative substrate having a natural oxide film with a thickness of 10 nm and a target substrate having oxide film 53 with a thickness of 30 nm at room temperature, and performed an experiment to determine whether or not sulfurization had progressed in each substrate. As a result of the experiment, although not shown in the figures, it was confirmed that sulfurization progressed and corrosion occurred in the comparative substrate. On the other hand, no degradation was observed in the control substrate. Therefore, it was found that deterioration of the base material 52 can be suppressed by artificially forming the oxide film 53 on the base material 52 by a predetermined treatment. It was also found that the thickness of the oxide film 53 is preferably 30 nm or more.

[0040] [Effects of the first embodiment] The projector 1 according to the present embodiment described above provides the following advantages. The projector 1 includes a light source device 4, an image light generation device 30 that generates image light from the light of the light source device 4, and a projection optical device 36 that projects the generated image light. The light source device 4 includes a solid-state light source 41 that emits excitation light, and a wavelength conversion device 5 that converts the wavelength of the excitation light.

[0041] The wavelength converter 5 includes a base material 52 , an oxide film 53 , a bonding film 54 , a bonding material 55 , and a wavelength conversion element 56 . The base material 52 is made of either copper or a copper alloy. The bonding film 54 is disposed on the first surface 521 of the base material 52. The bonding material 55 is disposed on the bonding film 54 . The wavelength conversion element 56 is disposed in the bonding material 55 . The oxide film 53 is formed on all surfaces of the base material 52 on which the bonding film 54 does not exist. That is, the oxide film 53 is formed on all surfaces of the base material 52 except for the first surface 521.

[0042] According to this configuration, the oxide film 53 is formed on the base material 52, so that the area of ​​the base material 52 exposed to the outside can be reduced, and corrosion of the base material 52 can be suppressed. Therefore, it is possible to suppress the metal pieces from falling off the base material 52 due to corrosion and affecting the surrounding members. This also makes it possible to suppress the optical components to which the metal pieces are attached from being damaged by heat generation. Furthermore, since the light source device 4 includes the wavelength conversion device 5, it can achieve the same effects as the wavelength conversion device 5. Therefore, it is possible to suppress adhesion of metal pieces to the optical components around the wavelength conversion device 5, and therefore it is possible to suppress a decrease in the amount of illumination light emitted from the light source device 4, and it is possible to configure a light source device 4 that is highly durable and can be used stably. Furthermore, since the projector 1 includes the light source device 4, it can achieve the same effect as the light source device 4. Therefore, it is possible to suppress a decrease in the amount of light emitted from the light source device 4, and therefore it is possible to configure the projector 1 that can stably project the image light, thereby suppressing a decrease in the brightness of the image light.

[0043] In the wavelength converter 5, the oxide film 53 has a thickness of 30 nm or more. Here, the thickness of the natural oxide film formed naturally on the surface of the substrate made of either copper or a copper alloy is approximately 10 nm or less. In the substrate on which the natural oxide film is formed, there is a risk that metal pieces will fall off due to corrosion. In contrast, the thickness of an artificially formed oxide film can be 30 nm or more, and if the thickness of the oxide film 53 is 30 nm or more, it is possible to reliably prevent corrosion from occurring in the base material 52. Therefore, it is possible to increase the durability of the wavelength converter 5 and reliably prevent metal pieces from falling off.

[0044] In the wavelength converter 5, the bonding film 54 is disposed over the entire first surface 521. The oxide film 53 is disposed over all surfaces other than the first surface 521. That is, the entire first surface 521 of the base material 52 is covered with the bonding film 54, and the oxide film 53 is formed over all surfaces of the base material 52 other than the first surface 521. In other words, the oxide film 53 is formed over the entire surfaces of all surfaces of the base material 52 where the bonding film 54 is not present. According to such a configuration, the area of ​​the base material 52 exposed to the outside can be further reduced, thereby further suppressing corrosion of the base material 52. Therefore, the durability of the wavelength converter 5 can be further improved and falling off of metal pieces can be further suppressed.

[0045] The manufacturing process of the wavelength converter 5 includes a bonding film forming step S1, a bonding material arranging step S2, a wavelength conversion element arranging step S3, and an oxide film forming step S4. In the bonding film forming step S1, a bonding film 54 is formed on a first surface 521 of a base material 52 made of either copper or a copper alloy. In the bonding material applying step S2, a bonding material 55 is applied to the bonding film . In the wavelength conversion element arrangement step S3, the wavelength conversion element 56 is arranged on the bonding material 55. In the oxide film forming step S4, the bonding material 55 is fixed by heat treatment, and an oxide film is formed on all surfaces of the base material 52 where the bonding film 54 does not exist. The bonding film forming step S1, the bonding material arranging step S2, the wavelength conversion element arranging step S3, and the oxide film forming step S4 constitute a method for manufacturing the wavelength conversion device 5. According to such a manufacturing process, the bonding film 54 and the bonding material 55 can be fixed to each other, and the oxide film 53 can be formed on the base material 52 in one step. Therefore, the wavelength converter 5 can be manufactured efficiently.

[0046] [Second embodiment] Next, a second embodiment of the present disclosure will be described. The projector according to this embodiment has a similar configuration to the projector 1 according to the first embodiment, but differs in the range in which the bonding film 54 constituting the wavelength conversion device 5 is formed. In the following description, parts that are the same or approximately the same as parts already described will be denoted by the same reference numerals and description thereof will be omitted.

[0047] [Projector and light source configuration] FIG. 5 is a cross-sectional view showing a wavelength conversion device 5A provided in the light source device of the projector according to this embodiment. The projector according to this embodiment has the same configuration and functions as the projector 1 according to the first embodiment, except that it has a wavelength conversion device 5A shown in Fig. 5 instead of the wavelength conversion device 5 according to the first embodiment. That is, the light source device according to this embodiment has the same configuration and functions as the light source device 4 according to the first embodiment, except that it has a wavelength conversion device 5A instead of the wavelength conversion device 5.

[0048] [Configuration of wavelength conversion device] The wavelength converter 5A has the same configuration and function as the wavelength converter 5. That is, as shown in Fig. 5, the wavelength converter 5A includes a substrate 51A having a base material 52 and an oxide film 53, a bonding film 54, a bonding material 55, and a wavelength conversion element 56, as well as a heat dissipation member 57 and thermally conductive grease, which are not shown in Fig. 5. The wavelength converter 5A can be manufactured by the same manufacturing process as the wavelength converter 5.

[0049] In the wavelength converter 5 according to the first embodiment, the bonding film 54 is formed on approximately the entire first surface 521 of the base material 52. In contrast, in the wavelength conversion device 5A according to the present embodiment, the bonding film 54 is formed on a part of the first surface 521. Specifically, the bonding film 54 is formed in the center of the first surface 521 as viewed from the +Z direction in the above-described bonding film forming step S1. Therefore, the bonding film 54 is not formed on the peripheral portion of the first surface 521, and in the bonding material arranging step S2, the bonding material 55 is provided in the center of the bonding film 54 as viewed from the +Z direction.

[0050] In such a wavelength converter 5A, the oxide film 53 formed on the surface of the base material 52 in the oxide film forming step S4 is formed on the entire surfaces of the second surface 522, the third surface 523, the fourth surface 524, the fifth surface, and the sixth surface of the base material 52 where the bonding film 54 is not present, and is also formed in an area of ​​the first surface 521 where the bonding film 54 is not provided. That is, the oxide film 53 in the wavelength converter 5A is formed on a portion of the base material 52 that is not covered by the bonding film 54 and is exposed to the outside.

[0051] [Effects of the second embodiment] The projector according to this embodiment described above provides the following effects in addition to the effects similar to those of the projector 1 according to the first embodiment. In the wavelength converter 5A, the bonding film 54 is disposed on a part of the first surface 521 of the base material 52. The oxide film 53 is disposed on the surfaces of the base material 52 other than the first surface 521, and also on the entire region of the first surface 521 where the bonding film 54 is not disposed. According to such a configuration, since the region of the base material 52 that is not covered with the oxide film 53 and is exposed to the outside can be almost completely eliminated, corrosion of the base material 52 can be reliably suppressed. Therefore, the durability of the wavelength converter 5A can be further improved. In addition, since falling off of the metal pieces can be reliably suppressed, adhesion of the metal pieces to the optical components around the wavelength converter 5A can be suppressed, and thus the optical components can be prevented from being damaged due to heat generation at the sites where the metal pieces are attached.

[0052] [Modifications of the embodiment] The present disclosure is not limited to the above-described embodiments, and modifications and improvements within the scope that can achieve the object of the present disclosure are included in the present disclosure. In each of the above embodiments, the oxide film 53 is formed on all of the surfaces of the base material 52 on which the bonding film 54 is not present. That is, the oxide film 53 is formed on each of the second surface 522, the third surface 523, the fourth surface 524, the fifth surface, and the sixth surface of the base material 52 having the bonding film 54 disposed on the first surface 521. The oxide film 53 is formed on the entire surface of each surface on which the oxide film 53 is provided. However, this is not limited to the above, and the oxide film 53 may be formed on a part of the surface on which the oxide film 53 is provided.

[0053] In each of the above embodiments, the wavelength conversion element 56 is bonded to the base material 52 by the bonding film 54 and the bonding material 55. However, this is not limited thereto, and the bonding layer bonding the base material 52 and the wavelength conversion element 56 may include other layers in addition to the bonding film 54 and the bonding material 55. For example, another film may be provided between the bonding material 55 and the wavelength conversion element 56.

[0054] In each of the above embodiments, the thickness of the oxide film 53 formed on the base material 52 is 30 nm or more. However, this is not limited thereto, and the thickness of the oxide film 53 may be less than 30 nm. For example, when the oxide film 53 is made to function as a corrosion suppression film for the base material 52, the thickness of the oxide film 53 is preferably 10 nm or more, and more preferably 30 nm or more.

[0055] In the second embodiment, the bonding film 54 is disposed on a part of the first surface 521 of the base material 52, and the oxide film 53 is formed on the entire region of the first surface 521 where the bonding film 54 is not disposed. However, the present invention is not limited to this, and the oxide film 53 may be formed on a part of the region of the first surface 521 where the bonding film 54 is not disposed, or the oxide film 53 may not be formed in the region. In other words, the oxide film 53 may not be formed on the first surface 521 regardless of the region of the bonding film 54 on the first surface 521.

[0056] In each of the above embodiments, the wavelength converter 5, 5A is manufactured by a manufacturing process including a bonding film forming step S1, a bonding material arranging step S2, a wavelength conversion element arranging step S3, and an oxide film forming step S4. However, the present invention is not limited to this, and the wavelength converter 5, 5A may be manufactured by a manufacturing process and method other than the above manufacturing processes. For example, the formation of the oxide film 53 on the base material 52 and the diffusion bonding of the bonding film 54 and the bonding material 55 may be performed in different steps. In addition, the heat dissipation member arranging step S5 may be omitted.

[0057] In each of the above embodiments, the wavelength conversion element 56 has the reflective layer 561 and the phosphor layer 562, and the wavelength conversion device 5, 5A including the wavelength conversion element 56 is a reflective wavelength conversion device that emits converted light obtained by converting the wavelength of the excitation light in the direction opposite to the incident direction of the excitation light. However, this is not limited to the above, and the wavelength conversion element 56 does not need to include the reflective layer 561, and the wavelength conversion device 5, 5A may be a transmissive wavelength conversion device that emits converted light along the incident direction of the excitation light.

[0058] In each of the above embodiments, the projector includes three light modulation elements 343R, 343G, and 343B. However, the present disclosure is not limited to this, and can also be applied to a projector including two or less light modulation elements, or four or more light modulation elements. In the above embodiment, the image projection device 3 is configured to be substantially L-shaped as shown in Fig. 1. However, the present invention is not limited to this, and the image projection device may be configured to be, for example, substantially U-shaped.

[0059] In each of the above embodiments, the light modulation device 34 has a transmissive liquid crystal panel with different light entrance and exit surfaces. However, the present invention is not limited to this, and the light modulation device may have a reflective liquid crystal panel with the same light entrance and exit surfaces. In addition, as long as the light modulation device is capable of modulating the incident light beam to form an image according to image information, a device using a micromirror, for example, a device using a DMD (Digital Micromirror Device) or the like, other than a liquid crystal, may be used.

[0060] In each of the above embodiments, the light source device 4 is applied to a projector. However, the light source device according to the present disclosure may be used in lighting fixtures, headlights of automobiles, and the like.

[0061] [Summary of this disclosure] The following is a summary of this disclosure. [Appendix 1] A substrate made of copper or a copper alloy; a bonding film disposed on a first surface of the base material; A bonding material disposed on the bonding film; A wavelength conversion element disposed in the bonding material; an oxide film formed on all of the surfaces of the base material on which the bonding film is not present; A wavelength conversion device characterized by:

[0062] According to this configuration, the oxide film is formed, so that the area of ​​the base material exposed to the outside can be reduced, and therefore corrosion of the base material can be suppressed, and therefore, the metal pieces can be prevented from falling off the base material due to corrosion, which can affect the surrounding members.

[0063] [Appendix 2] 2. The wavelength converter according to claim 1, The thickness of the oxide film is 30 nm or more. A wavelength conversion device characterized by: Here, the thickness of the natural oxide film formed naturally on the surface of the substrate made of either copper or a copper alloy is approximately 10 nm or less. In the substrate on which the natural oxide film is formed, there is a risk that metal pieces will fall off due to corrosion. In contrast, the thickness of the artificially formed oxide film can be 30 nm or more, and if the thickness of the oxide film is 30 nm or more, the occurrence of corrosion in the base material can be reliably suppressed, which not only increases the durability of the wavelength conversion device but also reliably suppresses the falling off of metal pieces.

[0064] [Appendix 3] In the wavelength conversion device according to claim 1 or 2, the bonding film is disposed on the entire first surface, the oxide film is disposed on the entirety of all surfaces other than the first surface; A wavelength conversion device characterized by: According to this configuration, the area of ​​the base material exposed to the outside can be further reduced, so that corrosion of the base material can be further suppressed, and thus the durability of the wavelength conversion device can be further improved and the falling off of metal pieces can be further suppressed.

[0065] [Appendix 4] In the wavelength conversion device according to claim 1 or 2, the bonding film is disposed on a portion of the first surface, the oxide film is disposed on the entire area of ​​the first surface where the bonding film is not disposed; A wavelength conversion device characterized by: According to this configuration, since the area of ​​the base material that is not covered with the oxide film and is exposed to the outside can be almost completely eliminated, corrosion of the base material can be reliably suppressed, and therefore the durability of the wavelength conversion device can be further improved and the falling off of metal pieces can be reliably suppressed.

[0066] [Appendix 5] A solid-state light source that emits excitation light; and a wavelength conversion device according to any one of Supplementary Note 1 to Supplementary Note 4, which converts the wavelength of the excitation light. A light source device characterized by: According to such a configuration, it is possible to obtain the same effects as the wavelength conversion device described above, and it is possible to configure a light source device that is highly durable and can be used stably.

[0067] [Appendix 6] A light source device according to claim 5; an image light generating device that generates image light from the light of the light source device; A projection optical device that projects the generated image light. A projector characterized by: According to such a configuration, it is possible to obtain the same effect as the above-mentioned light source device, and it is possible to configure a projector capable of stably projecting image light.

[0068] [Appendix 7] forming a bonding film on a first surface of a base material made of copper or a copper alloy; A bonding material is placed on the bonding film; A wavelength conversion element is disposed on the bonding material; The bonding material is fixed by heat treatment, and an oxide film is formed on all surfaces of the base material on which the bonding film does not exist. A method for manufacturing a wavelength converter comprising the steps of: According to this configuration, the bonding film and the bonding material can be fixed to each other and the oxide film can be formed on the base material in a single process, so that the wavelength conversion device having the above-mentioned effects can be efficiently manufactured. [Explanation of symbols]

[0069] 1...projector, 30...image light generating device, 36...projection optical device, 4...light source device, 41...solid-state light source, 5,5A...wavelength conversion device, 51,51A...substrate, 52...base material, 53...oxide film, 54...bonding film, 55...bonding material, 56...wavelength conversion element, S1...bonding film formation process, S2...bonding material arrangement process, S3...wavelength conversion element arrangement process, S4...oxide film formation process.

Claims

1. A substrate made of copper or a copper alloy; a bonding film disposed on a first surface of the base material; A bonding material disposed on the bonding film; A wavelength conversion element disposed in the bonding material; an oxide film formed on all of the surfaces of the base material on which the bonding film is not present; A wavelength conversion device characterized by:

2. 2. The wavelength conversion device according to claim 1, The thickness of the oxide film is 30 nm or more. A wavelength conversion device characterized by:

3. 3. The wavelength conversion device according to claim 1, the bonding film is disposed on the entire first surface, The oxide film is disposed on the entirety of all surfaces other than the first surface. A wavelength conversion device characterized by:

4. 3. The wavelength conversion device according to claim 1, the bonding film is disposed on a portion of the first surface, the oxide film is disposed on the entire area of ​​the first surface where the bonding film is not disposed; A wavelength conversion device characterized by:

5. A solid-state light source that emits excitation light; and a wavelength conversion device according to claim 1 or 2, which converts the wavelength of the excitation light. A light source device characterized by:

6. The light source device according to claim 5 ; an image light generating device that generates image light from the light of the light source device; A projection optical device that projects the generated image light. A projector characterized by:

7. forming a bonding film on a first surface of a base material made of copper or a copper alloy; A bonding material is placed on the bonding film; A wavelength conversion element is disposed on the bonding material; The bonding material is fixed by heat treatment, and an oxide film is formed on all surfaces of the base material on which the bonding film does not exist. A method for manufacturing a wavelength converter comprising the steps of:

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