JP2020052413A - Wavelength conversion element, method for manufacturing wavelength conversion element, light source device and projector - Google Patents

Abstract

To provide a wavelength conversion element suppressing reduction in extraction efficiency of fluorescent light, to provide a light source device including the wavelength conversion element, and to provide a projector including the light source device.SOLUTION: The wavelength conversion element of the present invention includes: a wavelength conversion layer having a first surface where excitation light enters and a second surface opposing to the first surface; a first layer disposed opposing to the second surface and containing a first inorganic oxide; a second layer disposed opposing to the first surface and containing a first metal or a second inorganic oxide different from the first inorganic oxide; and a third layer disposed opposing to the second layer, containing either silver or aluminum, and reflecting the excitation light or light resulting from the wavelength conversion of the excitation light by the wavelength conversion layer.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a wavelength conversion element, a method for manufacturing a wavelength conversion element, a light source device, and a projector.

  2. Description of the Related Art In recent years, there is an illumination device for a projector that uses fluorescent light as illumination light. For example, Patent Literature 1 below discloses a light emitting device including a light source that emits laser light and a fluorescent light emitting unit that emits fluorescent light when laser light is incident. In this light emitting device, the fluorescent light emitting section includes a phosphor layer, a substrate supporting the phosphor layer, and a reflective layer provided between the substrate and the phosphor layer. Then, the fluorescent light emitting section extracts the fluorescent light generated by the fluorescent material layer as illumination light by reflecting the fluorescent light on the reflective layer.

  It is desirable that the reflection layer as described above has excellent durability. For example, Patent Document 2 below discloses that an Ag film is used as a reflective layer that is strong against heat and light.

JP 2015-119046 A WO 2015/194455

  Therefore, it is conceivable to use an Ag film as a reflection layer that reflects the fluorescence generated by the phosphor layer. However, when an Ag film is used as a fluorescent reflection film, Ag aggregates due to heat or light in the phosphor, the film becomes non-uniform, and the reflectance decreases, thereby lowering the fluorescence extraction efficiency. In addition, the durability of the reflection film also decreases.

  An object of the present invention is to solve the above-described problems, and it is an object of the present invention to provide a wavelength conversion element and a method for manufacturing a wavelength conversion element that suppress a decrease in the efficiency of extracting fluorescence. Another object is to provide a light source device including the wavelength conversion element. Another object is to provide a projector including the light source device.

  According to a first aspect of the present invention, a first surface on which excitation light is incident, a wavelength conversion layer having a second surface facing the first surface, and a wavelength conversion layer provided facing the second surface, A first layer containing an inorganic oxide, and a second layer provided opposite to the first layer and containing a first metal or a second inorganic oxide different from the first inorganic oxide And a third layer provided to face the second layer and containing either silver or aluminum, wherein the excitation light reflects the light whose wavelength has been converted by the wavelength conversion layer or the excitation light, The wavelength conversion element provided with this is provided.

  According to the wavelength conversion element according to the first aspect, the second layer is provided on the surface of the third layer on the incident side of the excitation light, so that the second layer reduces the deterioration of the third layer. For this reason, the reflectance of the third layer is unlikely to decrease due to the deterioration, so that the component of the wavelength-converted light that has entered the third layer can be satisfactorily reflected and emitted from the wavelength conversion layer. Therefore, it is possible to suppress a decrease in the extraction efficiency of the wavelength-converted light.

  In the first aspect, a fourth layer that is provided to face the third layer and contains the first metal or a second metal different from the first metal, and a fourth layer that faces the fourth layer. And a fifth layer containing the first inorganic oxide or the second inorganic oxide.

  According to this configuration, the protection performance of the third layer can be improved.

  In the first aspect, it is preferable that the wavelength conversion element and the base material are joined by a joining material provided between the fifth layer and the base material, further comprising a base material.

  According to this configuration, the heat generated in the wavelength conversion element is transmitted to the substrate through the third layer. Therefore, since the heat dissipation of the wavelength conversion element is increased, a decrease in the luminous efficiency of the wavelength conversion element can be reduced.

  In the first aspect, it is preferable that the first metal of the second layer contains at least one metal selected from Al, Ni, Ti, W, and Nb.

  According to this configuration, a configuration that suppresses deterioration of the third layer can be realized.

  In the first aspect, the second inorganic oxide of the second layer is preferably an oxide conductive material or an amorphous conductive oxide.

  According to this configuration, since the second layer has optical transparency, it is possible to realize a configuration in which the excitation light is efficiently incident on the third layer and deterioration of the third layer is suppressed.

  In the first aspect, it is preferable that a sixth layer containing the first metal or the second inorganic oxide is further provided between the third layer and the fourth layer.

  According to this configuration, the provision of the sixth layer can further reduce the deterioration of the third layer.

  In the first aspect, the first metal of the sixth layer preferably contains at least one metal selected from Al, Ni, Ti, W, and Nb.

  According to this configuration, it is possible to realize a configuration in which the first metal further reduces the deterioration of the third layer.

  In the first aspect, the second inorganic oxide of the sixth layer is preferably an oxide conductive material or an amorphous conductive oxide.

  According to this configuration, a configuration in which the deterioration of the third layer is further reduced by the second inorganic oxide can be realized.

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

  According to the light source device according to the second aspect, it is possible to provide a light source device in which a decrease in the efficiency of extracting the fluorescent light YL is suppressed.

  According to a third aspect of the present invention, a light source device according to the second aspect, a light modulator that forms image light by modulating light from the light source device according to image information, And a projection optical system for projecting.

  Since the projector according to the third aspect includes the light source device according to the second aspect, a high-luminance image can be formed.

  According to a fourth aspect of the present invention, a first step of forming a wavelength conversion layer having a first surface and a second surface opposed to each other, and a first step in which the wavelength conversion layer is opposed to the second surface. A second step of forming a first layer containing an inorganic oxide, and a second metal oxide different from the first metal or the first inorganic oxide at a position facing the first layer. A third step of forming a second layer containing silver or aluminum at a position facing the second layer, wherein the light contains one of silver and aluminum and whose excitation light is wavelength-converted by the wavelength conversion layer or the excitation light. And a fourth step of forming a third layer that reflects light.

  According to the method for manufacturing a wavelength conversion element according to the fourth aspect, it is possible to manufacture a wavelength conversion element in which a reduction in extraction efficiency of wavelength-converted light is suppressed.

  In the fourth aspect, the first layer includes a first inorganic oxide layer and a second inorganic oxide layer, and the second step includes forming the first inorganic oxide layer on the second surface using a chemical vapor deposition method. Preferably, the method includes a first forming step of forming an oxide layer and a second forming step of forming the second inorganic oxide layer on the first total reflection layer by using a physical vapor deposition method.

  According to this configuration, by forming the first inorganic oxide layer using a chemical vapor deposition method, for example, even when a concave portion is formed on the second surface, the first inorganic oxide layer is formed in the concave portion. Can be formed. Thereby, the influence of the unevenness of the concave portion is reduced, so that the surface of the first inorganic oxide layer formed on the second surface can be made flat. Further, since the second inorganic oxide layer is formed on the first total reflection layer by using a physical vapor deposition method applicable to various film formations such as a metal film and an oxide film, the second inorganic oxide layer Subsequent to the film formation, another film constituting the first layer can be efficiently formed.

Further, it is more preferable to use SiO ₂ as a material of the first inorganic oxide layer and the second inorganic oxide layer.
With this configuration, since the first inorganic oxide layer and the second inorganic oxide layer are formed of the same material, the adhesion between the first inorganic oxide layer and the second inorganic oxide layer can be further increased. .

FIG. 1 is a diagram illustrating a schematic configuration of a projector according to a first embodiment. It is a figure showing the schematic structure of a lighting installation. It is sectional drawing which shows the principal part structure of a wavelength conversion element. It is sectional drawing which shows the principal part structure of a fluorescent substance layer. It is a figure showing a manufacturing process of a wavelength conversion element concerning a modification of a first embodiment. It is a figure showing a manufacturing process of a wavelength conversion element concerning a modification of a first embodiment. It is sectional drawing which shows the principal part structure of the wavelength conversion element of 2nd embodiment. It is sectional drawing which shows the principal part structure of the wavelength conversion element of 3rd embodiment. It is sectional drawing which shows the principal part structure of the wavelength conversion element of 4th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the characteristics easy to understand, the characteristic portions may be enlarged for convenience, and the dimensional ratios and the like of the respective components are not necessarily the same as the actual ones. Absent.

(First embodiment)
First, an example of the projector according to the embodiment will be described.
FIG. 1 is a diagram illustrating a schematic configuration of a projector according to the embodiment.
As shown in FIG. 1, the projector 1 of the present embodiment is a projection type image display device that displays a color image on a screen SCR. The projector 1 includes an illumination device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a combining optical system 5, and a projection optical system 6.

  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 includes a first dichroic mirror 7a and a second dichroic mirror 7b, a first total reflection mirror 8a, a second total reflection mirror 8b, a third total reflection mirror 8c, and a first dichroic mirror 8c. It generally includes a relay lens 9a and a second relay lens 9b.

  The first dichroic mirror 7a separates the illumination light WL from the illumination device 2 into a red light LR and other lights (green light LG and blue light LB). The first dichroic mirror 7a transmits the separated red light LR and reflects other lights (green light LG and blue light LB). On the other hand, the second dichroic mirror 7b separates other light into green light LG and blue light LB by reflecting the green light LG and transmitting the blue light LB.

  The first total reflection mirror 8a is arranged in the optical path of the red light LR, and reflects the red light LR transmitted through the first dichroic mirror 7a toward the light modulator 4R. On the other hand, the second total reflection mirror 8b and the third total reflection mirror 8c are arranged in the optical path of the blue light LB, and guide the blue light LB transmitted through the second dichroic mirror 7b to the light modulator 4B. The green light LG is reflected from the second dichroic mirror 7b toward the light modulator 4G.

  The first relay lens 9a and the second relay lens 9b are arranged downstream of the second dichroic mirror 7b in the optical path of the blue light LB.

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

  As the light modulator 4R, the light modulator 4G, and the light modulator 4B, for example, transmissive liquid crystal panels are used. Further, a polarizing plate (not shown) is arranged on each of the incident side and the emission side of the liquid crystal panel.

  In addition, a field lens 10R, a field lens 10G, and a field lens 10B are disposed on the incident side of the light modulator 4R, the light modulator 4G, and the light modulator 4B, respectively. The field lens 10R, the field lens 10G, and the field lens 10B collimate each of the red light LR, the green light LG, and the blue light LB incident on each of the light modulators 4R, 4G, and 4B.

  Image light from the light modulator 4R, the light modulator 4G, and the light modulator 4B is incident on the combining optical system 5. The combining optical system 5 combines the image lights respectively corresponding to the red light LR, the green light LG, and the blue light LB, and emits the combined image light to the projection optical system 6. For the combining optical system 5, for example, a cross dichroic prism is used.

  The projection optical system 6 includes a projection lens group, and enlarges and projects the image light synthesized by the synthesis optical system 5 toward the screen SCR. As a result, an enlarged color image is displayed on the screen SCR.

(Lighting device)
Subsequently, the lighting device 2 according to an embodiment of the present invention will be described. FIG. 2 is a diagram illustrating a schematic configuration of the lighting device 2. As shown in FIG. 2, the illumination device 2 includes a light source device 2A, an integrator optical system 31, a polarization conversion element 32, and a superimposing lens 33a. In the present embodiment, the integrator optical system 31 and the superimposing lens 33a constitute a superimposing optical system 33.

  The light source device 2A includes an array light source 21A, a collimator optical system 22, an afocal optical system 23, a first retardation plate 28a, a polarization separation element 25, a first condensing optical system 26, a wavelength It includes a conversion element 40, a second retardation plate 28 b, a second condensing optical system 29, and a diffuse reflection element 30.

  An array light source 21A, a collimator optical system 22, an afocal optical system 23, a first retardation plate 28a, a polarization splitting element 25, a second retardation plate 28b, and a second focusing optical system. 29 and the diffuse reflection element 30 are sequentially arranged on the optical axis ax1. On the other hand, the wavelength conversion element 40, the first condensing optical system 26, the polarization separation element 25, the integrator optical system 31, the polarization conversion element 32, and the superimposing lens 33a are sequentially arranged on the illumination optical axis ax2. It is arranged in. The optical axis ax1 and the illumination optical axis ax2 are in the same plane and are orthogonal to each other.

  The array light source 21A 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 orthogonal to the optical axis ax1. The semiconductor laser 211 emits, for example, a blue light beam BL (eg, a laser beam having a peak wavelength of 460 nm). The array light source 21A emits a light beam composed of a plurality of light beams BL. In the present embodiment, the array light source 21A corresponds to a “light source” in the claims.

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

  The light beam BL that has passed through the collimator optical system 22 enters the afocal optical system 23. The afocal optical system 23 adjusts the beam diameter of the light beam BL. The afocal optical system 23 includes, for example, a convex lens 23a and a concave lens 23b.

  The light beam BL that has passed through the afocal optical system 23 enters the first retardation plate 28a. The first retardation plate 28a is, for example, a rotatable half-wave plate. The 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 light beam BL transmitted through the first retardation plate 28a is converted into the S-polarized light component and the P-polarized light component with respect to the polarization separation element 25 at a predetermined ratio. Included rays. By rotating the first retardation plate 28a, the ratio between the S-polarized light component and the P-polarized light component can be changed.

  The light beam BL including the S-polarized light component and the P-polarized light component generated by passing through the first retardation plate 28a enters the polarization splitter 25. The polarization splitting element 25 is composed of, for example, a polarization beam splitter having wavelength selectivity. The polarization splitting element 25 also forms an angle of 45 ° with the optical axis ax1 and the illumination optical axis ax2.

  The polarization splitting element 25 has a polarization splitting function of splitting the light beam BL into a light beam BLs of S-polarized light component and a light beam BLp of P-polarized light component with respect to the polarization splitting device 25. Specifically, the polarization separation element 25 reflects the light beam BLs of the S polarization component and transmits the light beam BLp of the P polarization component.

  Further, the polarization separation element 25 has a color separation function of transmitting the fluorescent light YL having a wavelength band different from that of the light beam BL regardless of its polarization state.

  The S-polarized light beam BLs emitted from the polarization splitting element 25 enters the first focusing optical system 26. The first focusing optical system 26 focuses the light beam BLs toward the wavelength conversion element 40.

  In the present embodiment, the first condensing optical system 26 includes, for example, a first lens 26a and a second lens 26b. The light beam BLs emitted from the first focusing optical system 26 enters the wavelength conversion element 40 while being focused.

  The fluorescence YL generated by the wavelength conversion element 40 is collimated by the first condensing optical system 26 and then enters the polarization separation element 25. The fluorescent light YL passes through the polarization separation element 25.

On the other hand, the P-polarized light beam BLp emitted from the polarization separation element 25 enters the second retardation plate 28b. The second retardation plate 28b is configured by a quarter-wave plate disposed in the optical path between the polarization splitting element 25 and the diffuse reflection element 30. Therefore, the P-polarized light beam BLp emitted from the polarization splitting element 25 is converted into, for example, clockwise circularly polarized blue light BLc1 by the second retardation plate 28b, and then the second condensing optical system. It is incident on 29.
The second condensing optical system 29 includes, for example, convex lenses 29a and 29b, and makes the blue light BLc1 incident on the diffuse reflection element 30 in a state of being condensed.

  The diffuse reflection element 30 is arranged on the side of the polarization separation element 25 opposite to the phosphor layer 42, and diffusely reflects the blue light BLc 1 emitted from the second condensing optical system 29 toward the polarization separation element 25. As the diffuse reflection element 30, it is preferable to use an element that Lambertian-reflects the blue light BLc1 and does not disturb the polarization state.

  Hereinafter, the light diffusely reflected by the diffuse reflection element 30 is referred to as blue light BLc2. According to this embodiment, the blue light BLc2 having a substantially uniform illuminance distribution can be obtained by diffusing and reflecting the blue light BLc1. For example, clockwise circularly polarized blue light BLc1 is reflected as counterclockwise circularly polarized blue light BLc2.

  The blue light BLc2 is converted into parallel light by the second condensing optical system 29, and then enters the second phase difference plate 28b again.

  The counterclockwise 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 splitter 25 toward the integrator optical system 31.

  Thereby, the blue light BLs1 is used as the illumination light WL together with the fluorescent light YL transmitted through the polarization separation element 25. That is, the blue light BLs1 and the fluorescent light YL are emitted from the polarization separation element 25 in the same direction, and white illumination light WL in which the blue light BLs1 and the fluorescent light (yellow light) YL are mixed is generated.

  The illumination light WL is emitted toward the integrator optical system 31. The integrator optical system 31 includes, for example, a lens array 31a and a lens array 31b. The lens arrays 31a and 31b include a plurality of small lenses arranged in an array.

  The illumination light WL transmitted through the integrator optical system 31 enters the polarization conversion element 32. The polarization conversion element 32 includes a polarization separation film and a phase difference plate. The polarization conversion element 32 converts the illumination light WL including the unpolarized fluorescence YL into linearly polarized light.

  The illumination light WL transmitted through the polarization conversion element 32 enters the superimposing lens 33a. The superimposing lens 33a cooperates with the integrator optical system 31 to make the distribution of the illuminance by the illumination light WL in the illuminated area uniform. Thus, the illumination device 2 generates the illumination light WL.

(Wavelength conversion element)
As shown in FIG. 2, the wavelength conversion element 40 includes a base material 41 and a phosphor layer 42, and has a fixed type that does not rotate. The base material 41 has a first surface 41a on the first condensing optical system 26 side and a second surface 41b on the opposite side to the first surface 41a. The wavelength conversion element 40 further includes a reflection member 43 provided between the first surface 41a and the phosphor layer 42, and a heat radiation member 44 provided on the second surface 41b. In the present embodiment, the phosphor layer 42 corresponds to a “wavelength conversion layer” described in the claims.

  As a material of the base material 41, it is preferable to use a material having high heat conductivity and excellent heat dissipation, and examples thereof include metals such as aluminum and copper, and ceramics such as aluminum nitride, alumina, sapphire, and diamond. In the present embodiment, the base material 41 is formed using copper.

  In the present embodiment, the phosphor layer 42 is held on the first surface 41a of the base material 41 via a bonding material described later. The phosphor layer 42 converts part of the incident light into fluorescent light YL and emits it. Further, the reflection member 43 reflects the light incident from the phosphor layer 42 toward the first condensing optical system 26.

  The heat radiating member 44 is formed of, for example, a heat sink and has a structure having a plurality of fins. The heat radiating member 44 is provided on the second surface 41 b of the base material 41 opposite to the phosphor layer 42. The heat radiating member 44 is fixed to the base 41 by, for example, joining with a metal brazing (metal joining). In the wavelength conversion element 40, heat can be dissipated through the heat dissipating member 44, so that thermal degradation of the phosphor layer 42 can be prevented.

  In the present embodiment, the reflection member 43 is formed of a multilayer film in which a plurality of films are stacked. FIG. 3 is a cross-sectional view illustrating a main configuration of the wavelength conversion element 40. Specifically, FIG. 3 is a diagram showing a cross section of the reflection member 43. In FIG. 3, the illustration of the heat radiation member 44 is omitted. Hereinafter, the light beam BLs emitted from the first condensing optical system 26 and incident on the phosphor layer 42 is referred to as excitation light BLs.

  As shown in FIG. 3, the phosphor layer 42 includes a light incident surface 42A from which the excitation light BLs is incident and the fluorescent light YL is emitted, and a surface facing the light incident surface 42A, that is, the reflecting member 43. And a bottom surface 42B provided. In the present embodiment, the phosphor layer 42 corresponds to a “wavelength conversion layer” described in the claims, the light incident surface 42A corresponds to a “first surface” described in the claims, and the bottom surface 42B corresponds to It corresponds to the “second surface” described in the claims.

  In the present embodiment, the phosphor layer 42 is a ceramic phosphor formed by firing phosphor particles. As the phosphor particles constituting the phosphor layer 42, a YAG (Yttrium Aluminum Garnet) phosphor containing Ce ions is used.

  The material for forming the phosphor particles may be one type, or a mixture of particles formed by using two or more types of materials may be used. As the phosphor layer 42, a phosphor layer in which phosphor particles are dispersed in an inorganic binder such as alumina, a phosphor layer formed by firing a glass binder as an inorganic material and phosphor particles, and the like are preferably used. Used. Alternatively, the phosphor layer may be formed by firing the phosphor particles without using a binder.

  The reflection member 43 is provided on the bottom surface 42B side of the phosphor layer 42. The phosphor layer 42 on which the reflecting member 43 is formed is joined to the base 41 via a joining material 55. As the bonding material 55, for example, a nano silver paste is used. In addition, as the bonding material 55, for example, metal bonding using a metal braze may be used.

  The reflecting member 43 of the present embodiment includes a multilayer film 50, a deterioration preventing film 51, a reflecting layer 52, a first protective layer 53a, a second protective layer 53b, in this order from the bottom surface 42B side of the phosphor layer 42. It is configured by laminating the bonding auxiliary layer 54.

  The multilayer film 50 is a layer containing an inorganic oxide (first inorganic oxide), and includes a total reflection layer 50a that totally reflects light having an angle equal to or larger than the critical angle of the fluorescent light YL generated by the phosphor layer 42. , And the reflection-enhancing layers 50b, 50c, and 50d. The reflection-enhancing layers 50b, 50c, and 50d are for achieving a reflection-enhancing effect, and improve the extraction efficiency of the fluorescent light YL. The multilayer film 50 corresponds to a “first layer” described in the claims. The multilayer film 50 (the total reflection layer 50a) is provided in contact with or laminated on the bottom surface 42B of the phosphor layer 42.

In the present embodiment, for example, SiO ₂ is used as the total reflection layer 50a. By using SiO ₂ , the fluorescence YL can be favorably totally reflected.

Further, TiO ₂ was used as the enhanced reflection layer 50b, SiO ₂ was used as the enhanced reflection layer 50c, and Al ₂ O ₃ was used as the enhanced reflection layer 50d.

  In the present embodiment, the deterioration prevention film 51 is formed of a layer containing a metal. The deterioration prevention film 51 is for suppressing the deterioration of the reflection layer 52 as described later. The deterioration prevention film 51 corresponds to a “second layer” described in the claims.

  In the present embodiment, the deterioration prevention film 51 contains, for example, at least one metal (first metal) selected from Al, Ni, Ti, W, and Nb. In the present embodiment, Ti is used as the material of the deterioration prevention film 51. The film thickness is set, for example, to about 0.1 nm to 5 nm. If the film thickness is smaller than 0.1 nm, the effect of suppressing the deterioration of the reflective layer 52 is reduced, and if the film thickness is larger than 5 nm, the transmittance is reduced.

  The reflection layer 52 reflects a part of the fluorescent light YL generated by the phosphor layer 42 toward the bottom surface 42B toward the light incident surface 42A. The reflection layer 52 reflects the excitation light BLs incident on the phosphor layer 42 and incident on the reflection member 43 without being converted into fluorescence YL, and returns the excitation light BLs into the phosphor layer 42. Thereby, the fluorescent light YL can be efficiently generated. The reflection layer 52 corresponds to a “third layer” described in the claims.

  Ag or Al was used as the material of the reflection layer 52. In the present embodiment, Ag that obtains a higher reflectance is used as the material of the reflective layer 52. When Ag is used for the reflection layer 52, the deterioration prevention film 51 contains, for example, at least one metal selected from Al, Ni, Ti, W, and Nb. When Al is used for the reflection layer 52, the deterioration prevention film 51 contains, for example, at least one metal selected from Ni, Ti, W, and Nb.

  In the present embodiment, the cohesive energy of the element (Ti) forming the deterioration prevention film 51 is larger than the cohesive energy of the element (Ag) forming the reflective layer 52. Here, that the cohesive energy is large means that larger energy is required to cause coagulation.

  In the reflection layer 52 in which Ti having a large cohesive energy is formed on the light incident side, migration of Ag atoms due to heat is less likely to occur due to the action of Ti, so that occurrence of aggregation due to migration is reduced. That is, the reflection layer 52 is such that a decrease in reflectance and a decrease in durability due to the occurrence of aggregation are suppressed. According to the reflection member 43 of the present embodiment, since the deterioration prevention film 51 is provided, the deterioration of the reflection layer 52 can be reduced.

The first protective layer 53a and the second protective layer 53b have a function of protecting the reflective layer 52. The first protective layer 53a is made of a film containing a metal. The first protective layer 53a is made of, for example, a Ni film, and can promote crystallization of the reflective layer 52 (Ag film) to improve durability.
Note that the first protective layer 53a may be formed from a film containing the same metal as the deterioration preventing film 51. That is, when Ti is used as the material of the deterioration prevention film 51, Ti may be used as the material of the first protective layer 53a.

Further, the second protective layer 53b is formed of a layer containing an inorganic oxide. The second protective layer 53b is made of, for example, Al ₂ O ₃ and can suppress the oxidation of the reflective layer 52 (Ag film) and improve the adhesion with the bonding auxiliary layer 54 described later.
In the case where SiO ₂ , TiO ₂ , or Al ₂ O ₃ is used as the material of the multilayer film 50, the second protective layer 53 _b may be configured using a material different from these materials.
In the present embodiment, the first protective layer 53a corresponds to a “fourth layer” described in the claims, and the second protective layer 53b corresponds to a “fifth layer” described in the claims.

  The joining auxiliary layer 54 improves the reliability of the joining of the reflecting member 43 and the base material 41 by the joining material 55. By using, for example, an Ag layer as the bonding auxiliary layer 54, the thermal conductivity between the reflective member 43 and the base material 41 can be improved.

FIG. 4 is a cross-sectional view illustrating a main configuration of the phosphor layer 42.
As shown in FIG. 4, in the present embodiment, the phosphor layer 42 has a plurality of pores 42c provided therein. Thus, the phosphor layer 42 has light scattering characteristics due to the plurality of pores 42c.

  Since a part of the plurality of pores 42c is formed on the surface (bottom surface 42B) of the phosphor layer 42, a concave portion 42d is formed on the bottom surface 42B of the phosphor layer 42 by the pores 42c. The wavelength conversion device 20 of the present embodiment has a transparent member 45 that seals the recess 42d.

As the material of the transparent member 45, a light-transmitting inorganic material, for example, alumina, Y ₃ Al ₅ O ₁₂ , YAlO ₃ , zirconia, Lu ₃ Al ₅ O ₁₂ , SiO ₂ (glass paste), or anaerobic An adhesive is used. In the present embodiment, as the material of the transparent member 45, it is desirable to use the same material as the reflection member 43 formed on the bottom surface 22B of the phosphor layer 42.

Specifically, as the material of the transparent member 45, for example, the same SiO ₂ as the total reflection layer 50a can be used. By doing so, the transparent member 45 and the total reflection layer 50a (the first layer of the reflection member 43) can be formed by the same process.

  As described above, the reflection member 43 is formed by forming a plurality of layers on the bottom surface 42B of the phosphor layer 42. Here, if the flatness of the bottom surface 42B is low, it is difficult to satisfactorily form the respective layers constituting the reflection member 43. If the reflection member 43 cannot be formed on the bottom surface 42B satisfactorily, the fluorescent light YL cannot be reflected toward the light incident surface 42A, and the extraction efficiency of the fluorescent light YL is reduced.

  On the other hand, in the wavelength conversion element 40 of the present embodiment, the concave portion 42d is sealed by the transparent member 45 so that the bottom surface 42B is made substantially flat. Here, the substantially flat surface means a flatness such that the reflecting member 43 can be formed into a good film on the bottom surface 42B by vapor deposition or the like, and irregularities enough to form the reflecting member 43 can be allowed. .

  In the present embodiment, the transparent member 45 is made of the same material as the total reflection layer 50a. Therefore, the transparent member 45 and the total reflection layer 50a (reflection member 43) are formed integrally.

The wavelength conversion element 40 of the present embodiment is manufactured by, for example, a manufacturing method described below.
First, a mixture of the phosphor particles and the organic substance constituting the phosphor layer 42 is prepared, and the mixture is fired at a predetermined temperature.

  By the firing, the organic matter evaporates, and as shown in FIG. 4, a phosphor layer 42 including a plurality of pores 42c and made of a phosphor is formed. The size or number of the pores 42c can be adjusted by the firing temperature, the material of the organic substance, and the like.

  Subsequently, both surfaces of the phosphor layer 42 are ground and polished to form a phosphor layer 42 having a light incident surface 42A and a bottom surface 42B. A portion of the pores 42c is exposed to the outside by the grinding and polishing, and a concave portion 42d is formed on the bottom surface 42B of the phosphor layer 42.

Subsequently, a glass paste (SiO ₂ ) is applied to the bottom surface 42B by spin coating. Thus, the glass paste is applied to the entire bottom surface 42B in a state where the recess 42d is embedded.

  Then, by firing the glass paste, a transparent member 45 for sealing the concave portion 42d and a total reflection layer 50a integrally formed with the transparent member 45 are formed on the bottom surface 42B as shown in FIG. The method of applying the glass paste on the bottom surface 42B is not limited to the spin coating method, and a doctor blade method may be used.

  By sealing the recess 42d with the transparent member 45, the surface of the bottom surface 42B (total reflection layer 50a) can be made substantially flat. The temperature at which the glass paste is fired is lower than the temperature at which the mixture of the phosphor particles and the organic substance is fired.

  Subsequently, the reflection member 43 is formed by sequentially forming each layer on the total reflection layer 50a by vapor deposition, sputtering, or the like. Since the total reflection layer 50a has a substantially flat surface as described above, the reflection member 43 can be uniformly formed on the bottom surface 42B.

Subsequently, the laminate of the reflection member 43 and the phosphor layer 42 and the base material 41 are fixed via the bonding material 55. Finally, the wavelength conversion element 40 is manufactured by fixing the heat radiation member 44 to the surface of the base material 41 opposite to the phosphor layer 42.
In the above-described manufacturing method, the mixture of the phosphor particles and the inorganic substance constituting the phosphor layer 42 may be adjusted, and the mixture may be baked at a predetermined temperature, or the phosphor constituting the phosphor layer 42 may be baked. Only the body particles may be fired at a predetermined temperature.

  As described above, according to the wavelength conversion element 40 of the present embodiment, the deterioration preventing film 51 suppresses the deterioration due to the aggregation of the reflective layer 52 made of the Ag film. Therefore, since the reflectance of the reflection layer 52 is hardly reduced due to the deterioration, the component of the fluorescent light YL generated by the phosphor layer 42 incident on the bottom surface 42B side is favorably reflected and emitted from the light incident surface 42A. be able to. Therefore, it is possible to suppress a decrease in the extraction efficiency of the fluorescent light YL.

  In the present embodiment, the crystallization of the reflective layer 52 (Ag film) is promoted and the durability is improved by using a Ni film as the metal film constituting the first protective layer 53a for protecting the reflective layer 52. be able to.

Further, in the present embodiment, Al ₂ O ₃ is used as the inorganic oxide constituting the second protective layer 53 b that protects the reflective layer 52, thereby suppressing the oxidation of the reflective layer 52 (Ag film) and the bonding auxiliary layer described later. Adhesion with the substrate 54 can be improved.

  Further, in the present embodiment, the reflection member 43 is formed uniformly over the entire area of the bottom surface 42B by filling the recess 42d of the phosphor layer 42 with the transparent member 45. Therefore, of the fluorescence YL generated by the phosphor layer 42, the component incident on the bottom surface 42B side is favorably reflected by the reflection member 43 and emitted from the light incident surface 42A. Therefore, the efficiency of taking out the fluorescent light YL can be increased.

  Further, since the bottom surface 42B is a substantially flat surface, the contact area between the phosphor layer 42 and the reflecting member 43 can be increased. Thereby, the heat generated in the phosphor layer 42 is efficiently transmitted to the reflection member 43. The heat generated in the phosphor layer 42 is transmitted to the base 41 and the heat radiating member 44 via the reflecting member 43. Therefore, the heat dissipation of the phosphor layer 42 is improved.

  Since the heat radiation of the phosphor layer 42 is increased as described above, the heat radiation member 44 can be reduced in size, so that the wavelength conversion element 40 can be reduced in size.

Further, according to the wavelength conversion element 40 of the present embodiment, by increasing the heat dissipation of the phosphor layer 42, the temperature rise of the phosphor layer 42 is reduced, and the decrease in the luminous efficiency of the phosphor layer 42 can be reduced.
Therefore, the light source device 2A including the wavelength conversion element 40 can provide a light source device in which a decrease in the extraction efficiency of the fluorescent light YL is suppressed.
Further, according to the projector 1 of the present embodiment, since the illumination device 2 using the light source device 2A is provided, the projector 1 can form a high-luminance image.

(Modification of First Embodiment)
Subsequently, a modified example of the method for manufacturing the wavelength conversion element 40 of the first embodiment will be described. The same reference numerals are given to members common to the above embodiment, and detailed description is omitted.

First, the phosphor layer 42 (wavelength conversion layer) is formed (first step).
Specifically, a mixture of the phosphor particles and the organic material constituting the phosphor layer 42 is prepared, and the mixture is fired at a predetermined temperature.

  By baking, the organic matter evaporates, and as shown in FIG. 4, a phosphor layer 42 including a plurality of pores 42c and made of a phosphor is formed. The size or number of the pores 42c can be adjusted by the firing temperature, the material of the organic substance, and the like.

  Subsequently, both surfaces of the phosphor layer 42 are ground and polished to form a phosphor layer 42 having a light incident surface 42A and a bottom surface 42B. A portion of the pores 42c is exposed to the outside by the grinding and polishing, and a concave portion 42d is formed on the bottom surface 42B of the phosphor layer 42. Thus, the step of forming the phosphor layer 42 is completed.

Subsequently, a multilayer film 50 (first layer) is formed (second step).
In this modified example, the second step is a first forming step of forming a first inorganic oxide layer on the bottom surface 42B of the phosphor layer 42 by using a chemical vapor deposition method, and a physical vapor deposition method on the first total reflection layer. And a second forming step of forming a second inorganic oxide layer using the method.

Specifically, in the first forming step, a SiO ₂ film is formed on the bottom surface 42B of the phosphor layer 42 by chemical vapor deposition (CVD). In a CVD apparatus, the raw material density can be increased in accordance with the pressure in the chamber. Therefore, the film formation rate can be improved by appropriately increasing the pressure in the chamber. In the film formation by CVD, the directionality of the raw material molecules is lost due to collision in the gas phase.

As a result, as shown in FIG. 5A, the SiO ₂ film formed by CVD enters the concave portion 42d on the bottom surface 42B and covers the first total reflection layer 50a1 (SiO ₂₎ formed so as to cover the bottom surface 42B. ) Is formed. By performing the film formation by CVD in this manner, the first total reflection layer 50a1 is provided in the recess 42d, and the influence of the unevenness of the recess 42d is reduced. Therefore, the surface of the first total reflection layer 50a1 formed on the bottom surface 42B can be made a substantially flat surface (flat surface).

  In this modification, the thickness of the first total reflection layer 50a1 is preferably set to 600 nm or more. By setting the film thickness to 600 nm or more, the first total reflection layer 50a1 can efficiently emit the fluorescent light YL from the light incident surface 42A by total reflection. Further, since the first total reflection layer 50a1 enters the concave portion 42d, the influence of the concave portion 42d can be reduced.

Subsequently, in a second formation step, as shown in FIG. 5B, a second total reflection layer 50a2 (SiO ₂ ) is formed on the first total reflection layer 50a1 by physical vapor deposition (PVD). Thus, the total reflection layer 50a is formed.

  Note that the thickness of the second total reflection layer 50a2 is appropriately adjusted by other layers (increased reflection layers 50b, 50c, and 50d) of the multilayer film 50 that are in contact with the second total reflection layer 50a2.

  In this modification, the total reflection layer 50a includes a first total reflection layer 50a1 and a second total reflection layer 50a2. The first total reflection layer 50a1 corresponds to the “first inorganic oxide layer” described in the claims, and the second total reflection layer 50a2 corresponds to the “second inorganic oxide layer” described in the claims. I do.

In this modification, since the surface of the first total reflection layer 50a1 is substantially flat, the surface of the second total reflection layer 50a2 can also be substantially flat.
In the present modification, the first total reflection layer 50a1 and the second total reflection layer 50a2 are formed using the same material as the main component. Specifically, SiO ₂ was used as a material of the first total reflection layer 50a1 and the second total reflection layer 50a2. By forming the first total reflection layer 50a1 and the second total reflection layer 50a2 from the same material (SiO ₂ ), the adhesion between the first total reflection layer 50a1 and the second total reflection layer 50a2 is increased. Can be.

  Then, on the second total reflection layer 50a2, each layer (deterioration prevention film 51, reflection layer 52, first protection layer 53a, second protection layer 53b, and the like shown in FIG. 3) is formed by PVD (for example, evaporation or sputtering). The reflection member 43 is formed by sequentially forming the bonding auxiliary layer 54) (third step and fourth step). Since the second total reflection layer 50a2 has a substantially flat surface as described above, the reflection member 43 can be uniformly formed on the bottom surface 42B.

Subsequently, the laminate of the reflection member 43 and the phosphor layer 42 and the base material 41 are fixed via the bonding material 55. Finally, the wavelength conversion element 40 is manufactured by fixing the heat radiation member 44 to the surface of the base material 41 opposite to the phosphor layer 42.
In the above-described manufacturing method, the mixture of the phosphor particles and the inorganic substance constituting the phosphor layer 42 may be adjusted, and the mixture may be baked at a predetermined temperature, or the phosphor constituting the phosphor layer 42 may be baked. Only the body particles may be fired at a predetermined temperature.

As described above, according to the method of manufacturing the wavelength conversion element 40 according to the present modification, the transparent member 45 (SiO ₂ ) is formed in the recess 42d by forming the first total reflection layer 50a1 by using CVD. Can be formed.

In the present modification, the first total reflection layer 50a1 and the second total reflection layer 50a1 (the first total reflection layer 50a1 and the second total reflection layer 50a2) are formed of the same material (SiO ₂ ). The adhesion between the layers 50a2 can be increased. Therefore, the effects described in the first embodiment can be further enhanced.

Further, since the second total reflection layer 50a2 (SiO ₂ ) is formed by PVD after the first total reflection layer 50a1 is formed, each layer constituting the reflection member 43 is formed following the formation of the second total reflection layer 50a2. Can be efficiently formed. This is because, according to PVD, in addition to SiO ₂ , various films such as a metal film including an Ag reflection film and an oxide film can be formed.

Note that the material of the first total reflection layer 50a1 may not be SiO ₂ . For example, SiN or SiON may be used as the material of the first total reflection layer 50a1. In this case, it is desirable that the first total reflection layer 50a1 and the second total reflection layer 50a2 use the same material as the main component. For example, when using SiN as the material of the first total reflection layer 50a1, SiO ₂ may be used as the material of the second total reflection layer 50a2.

(Second embodiment)
Subsequently, a wavelength conversion element according to a second embodiment of the present invention will be described. The same reference numerals are given to members common to the above embodiment, and detailed description is omitted.

FIG. 6 is a cross-sectional view illustrating a main configuration of the wavelength conversion element 140 according to the present embodiment. Specifically, FIG. 6 is a diagram showing a cross section of the reflection member 143.
As shown in FIG. 6, the wavelength conversion element 140 includes a reflecting member 143 provided between the first surface 41a of the base material 41 and the phosphor layer 42.

  The reflecting member 143 of the present embodiment includes, in order from the bottom surface 42B side of the phosphor layer 42, the multilayer film 50, the deterioration preventing film 151, the reflecting layer 52, the first protective layer 53a, the second protective layer 53b, It is configured by laminating the bonding auxiliary layer 54.

  In the present embodiment, the deterioration prevention film 151 is formed of a layer containing an oxide conductive material or an amorphous conductive oxide as a light-transmitting inorganic oxide (second inorganic oxide). The deterioration prevention film 151 is for suppressing the deterioration of the reflection layer 52 as described later. The deterioration prevention film 151 corresponds to a “second layer” described in the claims.

In the present embodiment, the deterioration prevention film 151 is made of, for example, ITO (indium tin oxide), FTO (fluorine-doped tin oxide; SnO ₂ : F), or ATO (antimony-doped) as an oxide conductive material or an amorphous conductive oxide. Tin oxide; SnO ₂ : Sb), AZO (aluminum-doped zinc oxide; ZnO: Al), GZO (gallium-doped zinc oxide; ZnO: Ga), IZO (indium-doped zinc oxide), IGO (gallium-doped indium oxide), oxidation It contains at least one metal selected from zinc (ZnO) and tin oxide (SnO ₂ ). In this embodiment, ITO is used as the material of the deterioration prevention film 151. The film thickness of ITO is set, for example, to about 1 nm to 20 nm, and more preferably to about 3 to 15 nm. If the film thickness is smaller than 1 nm, the effect of suppressing the deterioration of the reflection layer 52 is reduced, and if the film thickness is larger than 20 nm, the transmittance is reduced.

  That is, according to the present embodiment, the degradation prevention film 151 having a large thickness can be formed on the reflection layer 52 within a range in which the light transmittance of the degradation prevention film 151 is ensured. Since the reflection layer 52 is covered with the deterioration prevention film 151, migration of Ag atoms due to heat hardly occurs.

  Therefore, in the reflective layer 52, occurrence of aggregation due to migration is reduced. That is, the reflection layer 52 is such that a decrease in reflectance and a decrease in durability due to the occurrence of aggregation are suppressed. According to the reflection member 143 of this embodiment, since the deterioration prevention film 151 is provided, the deterioration of the reflection layer 52 can be reduced.

  According to the wavelength conversion element 140 of the present embodiment of the present embodiment, since the reflectance of the reflective layer 52 is hardly reduced due to the deterioration, the fluorescent light YL generated by the phosphor layer 42 is preferably emitted from the light incident surface 42A. Can be done. Therefore, it is possible to suppress a decrease in the extraction efficiency of the fluorescent light YL.

  Since the deterioration prevention film 151 of the present embodiment has higher translucency than the deterioration prevention film 51 of the first embodiment, the thickness range of the deterioration prevention film can be widened. That is, it is possible to reduce the deterioration of the reflection layer 52 while increasing the film thickness.

(Third embodiment)
Subsequently, a wavelength conversion element according to a third embodiment of the present invention will be described. The same reference numerals are given to members common to the first embodiment, and detailed description is omitted.

FIG. 7 is a cross-sectional view illustrating a main configuration of the wavelength conversion element 240 according to the present embodiment. Specifically, FIG. 7 is a diagram showing a cross section of the reflection member 243.
As shown in FIG. 7, the wavelength conversion element 240 includes a reflection member 243 provided between the first surface 41a of the base material 41 and the phosphor layer 42.

  The reflecting member 243 of this embodiment includes a multilayer film 50, a first deterioration preventing film 251, a reflecting layer 52, a second deterioration preventing film 252, and a first protective layer in this order from the bottom surface 42B side of the phosphor layer 42. 53a, the second protective layer 53b, and the bonding auxiliary layer 54 are laminated.

  In the present embodiment, each of the first deterioration prevention film 251 and the second deterioration prevention film 252 is formed of a layer containing a metal. The first deterioration prevention film 251 corresponds to a “second layer” described in the claims, and the second deterioration prevention film 252 corresponds to a “sixth layer” described in the claims.

  In the present embodiment, the first deterioration prevention film 251 and the second deterioration prevention film 252 contain, for example, at least one metal selected from Al, Ni, Ti, W, and Nb. In the present embodiment, Ti is used as the material of the first deterioration prevention film 251 and the second deterioration prevention film 252, respectively. The materials for the first deterioration prevention film 251 and the second deterioration prevention film 252 may be different from each other.

  In the present embodiment, the cohesive energy of the element (Ti) forming each of the first deterioration preventing film 251 and the second deterioration preventing film 252 is larger than the cohesive energy of the element (Ag) forming the reflective layer 52. .

  In the present embodiment, since the reflective layer 52 is provided with Ti having a large cohesive energy on the light incident side and the light exit side, migration of Ag atoms is less likely to occur. Therefore, compared to the configuration of the first embodiment, the occurrence of aggregation due to migration is further reduced.

  According to the wavelength conversion element 240 of the present embodiment of the present embodiment, it is easier to suppress a decrease in the efficiency of extracting the fluorescent light YL.

(Fourth embodiment)
Subsequently, a wavelength conversion element according to a third embodiment of the present invention will be described. The same reference numerals are given to members common to the second embodiment, and detailed description is omitted.

FIG. 8 is a cross-sectional view illustrating a main configuration of the wavelength conversion element 340 according to the present embodiment. Specifically, FIG. 8 is a diagram showing a cross section of the reflection member 343.
As shown in FIG. 8, the wavelength conversion element 340 includes a reflection member 343 provided between the first surface 41a of the base material 41 and the phosphor layer 42.

  The reflecting member 343 of this embodiment includes, in order from the bottom surface 42B side of the phosphor layer 42, the multilayer film 50, the first deterioration preventing film 351, the reflecting layer 52, the second deterioration preventing film 352, and the first protective layer. 53a, the second protective layer 53b, and the bonding auxiliary layer 54 are laminated.

  In the present embodiment, each of the first deterioration prevention film 351 and the second deterioration prevention film 352 is formed of a layer containing a metal. The first deterioration prevention film 351 corresponds to a “second layer” described in claims, and the second deterioration prevention film 352 corresponds to a “sixth layer” described in claims.

In the present embodiment, the first deterioration prevention film 351 and the second deterioration prevention film 352 are made of an oxide conductive material or an amorphous conductive oxide, for example, ITO (indium tin oxide), FTO (fluorine-doped tin oxide; SnO). ₂ : F), ATO (antimony-doped tin oxide; SnO ₂ : Sb), AZO (aluminum-doped zinc oxide; ZnO: Al), GZO (gallium-doped zinc oxide; ZnO: Ga), IZO (indium-doped zinc oxide), It contains at least one metal selected from IGO (gallium-doped indium oxide), zinc oxide (ZnO), and tin oxide (SnO ₂ ).
In the present embodiment, ITO is used as the material of the first deterioration prevention film 351 and the second deterioration prevention film 352, respectively. The materials for the first deterioration prevention film 351 and the second deterioration prevention film 352 may be different from each other.

  In the present embodiment, since the reflection layer 52 is provided with the ITO films on the light incident side and the light exit side, migration of Ag atoms is less likely to occur. Therefore, compared to the configuration of the second embodiment, the occurrence of aggregation due to migration is further reduced.

  According to the wavelength conversion element 340 of the present embodiment of the present embodiment, it is easier to suppress a decrease in the extraction efficiency of the fluorescent light YL.

  The present invention is not limited to the contents of the above-described embodiment, and can be appropriately changed without departing from the gist of the invention.

  For example, in the above-described embodiment, at least one metal selected from Al, Ni, Ti, W, and Nb is used as the metal-containing deterioration prevention film 51, the first deterioration prevention film 251, and the second deterioration prevention film 252. Although those containing are exemplified, the present invention is not limited to these. For example, a film containing at least one metal (alloy) selected from a Zn—Ag alloy and a Sn—Ag alloy is used as the deterioration prevention film 51, the first deterioration prevention film 251, and the second deterioration prevention film 252. Is also good.

In the first embodiment, a layer made of the same material as the deterioration prevention film 51 may be disposed between the second protective layer 53b and the bonding auxiliary layer 54 made of an Ag layer.
In the second embodiment, a layer made of the same material as the deterioration prevention film 151 may be arranged between the second protective layer 53b and the bonding auxiliary layer 54 made of an Ag layer.
In the third embodiment, a layer made of the same material as any one of the first deterioration prevention film 251 and the second deterioration prevention film 252 is provided between the second protective layer 53b and the bonding auxiliary layer 54 formed of an Ag layer. It may be arranged.
In the fourth embodiment, a layer made of the same material as any one of the first deterioration preventing film 351 and the second deterioration preventing film 352 is provided between the second protective layer 53b and the bonding auxiliary layer 54 made of an Ag layer. It may be arranged.

  Further, in the above embodiment, the example in which the light source device according to the present invention is mounted on the projector has been described. The light source device according to the present invention can also be applied to lighting equipment, automobile headlights, and the like.

(Example)
The present inventor compared an example with a comparative example and performed an experiment to confirm the effectiveness of the present invention. In Example 1, an experiment was performed using a glass substrate instead of the phosphor and using a glass substrate having a reflective member formed on one surface as a sample.

  As a sample, the reflection layer constituting the reflection member is an Ag film, the deterioration prevention film is a layer made of Al, and the other layers (multilayer film, first protection layer, second protection layer, and bonding auxiliary layer) are the above-described embodiments. The same configuration as that described above was used. Note that the film was formed such that the thickness of the deterioration prevention film was about 1 nm.

Further, in Example 2, a sample having the same configuration as that of Example 1 was used as a sample except that the deterioration prevention film was made of Ti.
In the comparative example, a sample in which the deterioration suppressing film was omitted from the configuration of the first and second embodiments was used as a sample.

Then, for each of the samples of Examples 1 and 2 and the comparative example, light in the same wavelength band as the excitation light was applied from the other surface side of the glass substrate (the side opposite to the surface on which the reflecting member was provided) at 40 W / mm ² . After irradiating for 15 hours, the reflectance by the reflection member (reflection layer) was measured, and the results are shown in Table 1 below. The reflectance was measured for each of the three wavelengths (blue: 465 nm, green: 530 nm, red: 615 nm), and the reflectance retention was calculated. Note that the reflectance maintenance ratio is a ratio between the reflectance at the start of the experiment and the reflectance at the end of the experiment (after 15 hours). That is, a reflectance maintenance factor of 100% means that the reflective layer has not deteriorated at all.

  As shown in Table 1, in the comparative example, it was confirmed that the reflectance maintenance factor was less than 100% at any wavelength. On the other hand, in Examples 1 and 2, it was confirmed that the reflectance maintenance ratio could maintain 100% at any wavelength. That is, according to Examples 1 and 2 using the deterioration suppressing layer, it was confirmed that the reflection performance of the reflective layer could be maintained as compared with the comparative example. Thereby, it was confirmed that the deterioration of the reflective layer due to the excitation light can be suppressed by using the deterioration suppressing layer.

  After leaving each of the samples of Examples 1 and 2 and the comparative example in an environment of 350 ° C. for 72 hours, the reflectance by the reflection member (reflection layer) was measured, and the result of calculating the reflectance maintenance ratio was obtained. The results are shown in Table 2 below. The reflectance retention was calculated for each of the three wavelengths (blue: 465 nm, green: 530 nm, red: 615 nm).

  As shown in Table 2, in the comparative example, it was confirmed that the reflectance maintenance factor was lower than that of Examples 1 and 2 at any wavelength. Further, in Example 2, it was confirmed that the reflectance maintenance ratio could maintain 100% at any wavelength.

  That is, according to Examples 1 and 2 using the deterioration suppressing layer, it was confirmed that the reflection performance of the reflective layer could be maintained as compared with the comparative example. Thereby, it was confirmed that the deterioration of the reflective layer due to heat can be suppressed by using the deterioration suppressing layer. In addition, it was confirmed that when Ti was used as the deterioration suppressing layer, the heat resistance of the reflective layer was further improved.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2A ... Light source device, 4B, 4G, 4R ... Light modulator, 6 ... Projection optical system, 40, 140, 240, 340 ... Wavelength conversion element, 41 ... Base material, 42 ... Phosphor layer (wavelength conversion) Layers), 42A: light incident surface (first surface), 42B: bottom surface (second surface), 50: multilayer film (first layer), 50a1: first total reflection layer 50 (first inorganic oxide layer), 50a2: second total reflection layer 50 (second inorganic oxide layer), 51: deterioration prevention film (second layer), 52: reflection layer (third layer), 53a: first protective layer (fourth layer), 53b: second protective layer (fifth layer), 55: bonding material, 251, 351: first deterioration preventing film (second layer), 252, 352: second deterioration preventing film (sixth layer), BLs: excitation light.

According to a first aspect of the present invention, a first surface on which excitation light is incident, a wavelength conversion layer having a second surface facing the first surface, and a wavelength conversion layer provided facing the second surface, A first layer containing an inorganic oxide, and a second layer provided opposite to the first layer and containing a first metal or a second inorganic oxide different from the first inorganic oxide And a third layer provided opposite to the second layer and containing either silver or aluminum, wherein the excitation light reflects the light whose wavelength has been converted by the wavelength conversion layer or the excitation light, wherein the wavelength conversion layer may include pores inside, the second surface has a recess, a portion of the first layer, the wavelength conversion element that is provided in the recess is provided.

In the first aspect, a base material is further provided, and the wavelength conversion layer, the first layer, the second layer, and the third layer are formed by a bonding material provided between the third layer and the base material . It is preferable that the laminate and the substrate are fixed .

According to this configuration, the heat generated in the wavelength conversion layer is transmitted to the substrate through the third layer. Therefore, since the heat dissipation of the wavelength conversion element is increased, a decrease in the luminous efficiency of the wavelength conversion element can be reduced.

According to a fourth aspect of the present invention, the second surface of the wavelength conversion layer having a first surface and a second surface facing each other, a first layer containing a first inorganic oxide in direct contact A second step of forming;
Said first layer, a third step of the second layer containing different second inorganic oxide and the first metal or the first inorganic oxide is formed in direct contact,
Wherein the second layer, a fourth that contain either silver or aluminum, a third layer excitation light reflecting wavelength converted light or the excitation light by the wavelength conversion layer is formed in direct contact And a method for manufacturing a wavelength conversion element comprising the steps of:

In the fourth aspect, the first layer includes a first inorganic oxide layer and a second inorganic oxide layer, and the second step includes forming the first inorganic oxide layer on the second surface using a chemical vapor deposition method. Preferably, the method includes a first forming step of forming an oxide layer and a second forming step of forming the second inorganic oxide layer on the first inorganic oxide layer by using a physical vapor deposition method.

According to the wavelength conversion element 140 of the present embodiment, since the reflectance of the reflective layer 52 is hardly reduced due to the deterioration, the fluorescent light YL generated by the phosphor layer 42 can be favorably emitted from the light incident surface 42A. . Therefore, it is possible to suppress a decrease in the extraction efficiency of the fluorescent light YL.

According to the wavelength conversion element 240 of the present embodiment, it is easier to suppress a decrease in the efficiency of extracting the fluorescent light YL.

(Fourth embodiment)
Subsequently, a wavelength conversion element according to a fourth embodiment of the present invention will be described. The same reference numerals are given to members common to the second embodiment, and detailed description is omitted.

According to the wavelength conversion element 340 of the present embodiment, a decrease in the efficiency of extracting the fluorescent light YL can be more easily suppressed.

Claims (13)

A first surface on which the excitation light is incident, and a wavelength conversion layer having a second surface facing the first surface;
A first layer provided opposite to the second surface and containing a first inorganic oxide;
A second layer provided to face the first layer and containing a first metal or a second inorganic oxide different from the first inorganic oxide;
A third layer provided opposite to the second layer and containing either silver or aluminum, wherein the excitation light reflects light whose wavelength has been converted by the wavelength conversion layer or the excitation light. A wavelength conversion element characterized by the above-mentioned. A fourth layer provided to face the third layer and containing the first metal or a second metal different from the first metal;
The wavelength conversion according to claim 1, further comprising: a fifth layer provided to face the fourth layer and containing the first inorganic oxide or the second inorganic oxide. element. Further comprising a base material,
The wavelength conversion element according to claim 2, wherein the wavelength conversion element and the base material are bonded by a bonding material provided between the fifth layer and the base material. The said 1st metal of the said 2nd layer contains at least 1 type metal selected from Al, Ni, Ti, W, and Nb. The Claim 1 characterized by the above-mentioned. Wavelength conversion element. 4. The wavelength conversion element according to claim 1, wherein the second inorganic oxide of the second layer is an oxide conductive material or an amorphous conductive oxide. 5. The wavelength according to claim 2 or 3, further comprising a sixth layer containing the first metal or the second inorganic oxide, between the third layer and the fourth layer. Conversion element. The wavelength converter according to claim 6, wherein the first metal of the sixth layer contains at least one metal selected from Al, Ni, Ti, W, and Nb. The wavelength conversion element according to claim 6, wherein the second inorganic oxide of the sixth layer is an oxide conductive material or an amorphous conductive oxide. A wavelength conversion element according to any one of claims 1 to 8,
And a light source that emits the excitation light. A light source device according to claim 9,
A light modulation device that forms image light by modulating light from the light source device according to image information,
And a projection optical system that projects the image light. A first step of forming a wavelength conversion layer having a first surface and a second surface facing each other;
A second step of forming a first layer containing a first inorganic oxide at a position facing the second surface of the wavelength conversion layer;
A third step of forming a second layer containing a first metal or a second inorganic oxide different from the first inorganic oxide at a position facing the first layer;
A fourth step of forming a third layer containing either silver or aluminum at a position facing the second layer and reflecting light whose excitation light has been wavelength-converted by the wavelength conversion layer or which reflects the excitation light; And a method for producing a wavelength conversion element. The first layer includes a first inorganic oxide layer and a second inorganic oxide layer,
The second step is a first forming step of forming the first inorganic oxide layer on the second surface using a chemical vapor deposition method, and the first forming step is using a physical vapor deposition method on the first total reflection layer. The method according to claim 11, further comprising: a second forming step of forming two inorganic oxide layers. Method for manufacturing a wavelength conversion element according to claim 12, characterized in that SiO ₂ is used as the material of the first inorganic oxide layer and the second inorganic oxide layer.

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