JP7167906B2 - WAVELENGTH CONVERTER, WAVELENGTH CONVERSION METHOD, LIGHT SOURCE DEVICE, AND PROJECTOR - Google Patents

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, some lighting devices for projectors use fluorescence as illumination light. For example, Patent Literature 1 below discloses a light-emitting device that includes a light source that emits laser light and a fluorescent light-emitting portion that emits fluorescent light upon incidence of the laser light. 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. The fluorescent light emitting portion reflects the fluorescent light generated in the fluorescent layer by the reflective layer, thereby extracting the fluorescent light as illumination light.

It is desirable that the reflective layer as described above has excellent durability. For example, Patent Document 2 below discloses the use of an Ag film as a reflective layer resistant to heat and light.

JP 2015-119046 A WO2015/194455

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

An object of the present invention is to solve the above-described problems, and one of the objects is to provide a wavelength conversion element and a method for manufacturing the wavelength conversion element that suppresses deterioration in fluorescence extraction efficiency. Another object of the present invention 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 the first aspect of the present invention, a wavelength conversion layer having a first surface on which excitation light is incident and a second surface facing the first surface; A first layer containing an inorganic oxide of and a second layer provided opposite to the first layer and containing a second inorganic oxide different from the first metal or the first inorganic oxide and a third layer provided opposite to the second layer, containing either silver or aluminum, and reflecting the excitation light or the light obtained by wavelength conversion of the excitation light by the wavelength conversion layer; wherein the wavelength conversion layer includes pores therein, the second surface has a recess, and a portion of the first layer is provided in the recess to provide a wavelength conversion element.

According to the wavelength conversion element according to the first aspect, since the second layer is provided on the surface of the third layer on the excitation light incident side, deterioration of the third layer is reduced by the second layer. Therefore, since the third layer is less likely to deteriorate in reflectance, the component of the wavelength-converted light incident on the third layer can be well reflected and emitted from the wavelength conversion layer. Therefore, it is possible to suppress a decrease in extraction efficiency of wavelength-converted light.

In the first aspect, a fourth layer provided facing the third layer and containing the first metal or a second metal different from the first metal, and a fourth layer facing 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, a substrate is further provided, and the wavelength conversion layer, the first layer, the second layer, and the third layer are bonded by a bonding material provided between the third layer and the substrate. Preferably, the laminate and the substrate are fixed .

According to this configuration, the heat generated in the wavelength conversion layer is transmitted to the substrate side through the third layer. Therefore, since the heat dissipation of the wavelength conversion element is improved, it is possible to reduce the deterioration of the luminous efficiency of the wavelength conversion element.

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

With this configuration, it is possible to realize a configuration that suppresses deterioration of the third layer.

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

According to this configuration, since the second layer has a light-transmitting property, it is possible to achieve a configuration in which the deterioration of the third layer is suppressed while allowing the excitation light to enter the third layer efficiently.

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

According to this configuration, deterioration of the third layer can be further reduced by providing the sixth 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 achieve a configuration in which deterioration of the third layer is further reduced by the first metal.

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

According to this configuration, it is possible to achieve a configuration in which deterioration of the third layer is further reduced by the second inorganic oxide.

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 that suppresses deterioration in extraction efficiency of fluorescence YL.

According to a third aspect of the present invention, the light source device according to the second aspect, a light modulation device that modulates the light from the light source device according to image information to form image light, and the image light are: A projection optical system for projection is provided.

Since the projector according to the third aspect includes the light source device according to the second aspect, it is possible to form a high-brightness image.

According to the fourth aspect of the present invention, the first layer containing the first inorganic oxide is directly contacted with the second surface of the wavelength conversion layer having the first surface and the second surface facing each other. a second step of forming;
a third step of forming , in direct contact with the first layer, a second layer containing a first metal or a second inorganic oxide different from the first inorganic oxide;
A fourth layer in which a third layer that contains either silver or aluminum and reflects the excitation light or the light whose excitation light is wavelength-converted by the wavelength conversion layer is formed in direct contact with the second layer. A method for manufacturing a wavelength conversion element is provided, comprising the steps of:

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

In the above fourth aspect, the first layer comprises 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. It is preferable to include 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 using physical vapor deposition.

According to this configuration, by forming the first inorganic oxide layer using the chemical vapor deposition method, for example, even if the recess is formed on the second surface, the first inorganic oxide layer can be formed in the recess. can be formed. As a result, 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. In addition, since the second inorganic oxide layer is formed on the first total reflection layer by using a physical vapor deposition method that can be applied to various film formation such as a metal film and an oxide film, the second inorganic oxide layer is It is possible to efficiently form another film that constitutes the first layer following the film formation.

Further, it is more desirable to use SiO ₂ as the material for the first inorganic oxide layer and the second inorganic oxide layer.
In this way, since the first inorganic oxide layer and the second inorganic oxide layer are made of the same material, the adhesion between the first inorganic oxide layer and the second inorganic oxide layer can be further enhanced. .

1 is a diagram showing a schematic configuration of a projector according to a first embodiment; FIG. It is a figure which shows schematic structure of an illuminating device. FIG. 3 is a cross-sectional view showing a configuration of a main part of a wavelength conversion element; FIG. 3 is a cross-sectional view showing the configuration of a main part of a phosphor layer; It is a figure which shows the manufacturing process of the wavelength conversion element which concerns on the modification of 1st embodiment. It is a figure which shows the manufacturing process of the wavelength conversion element which concerns on the modification of 1st embodiment. FIG. 4 is a cross-sectional view showing the configuration of the essential parts of the wavelength conversion element of the second embodiment; FIG. 10 is a cross-sectional view showing the configuration of the main parts of the wavelength conversion element of the third embodiment; FIG. 11 is a cross-sectional view showing a configuration of a main part of a wavelength conversion element according to a fourth embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION 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 explanation, in order to make the features easier to understand, the characteristic portions may be enlarged for convenience, and the dimensional ratios of each component may not necessarily be the same as the actual ones. do not have.

(First embodiment)
First, an example of a projector according to this embodiment will be described.
FIG. 1 is a diagram showing a schematic configuration of a projector according to this embodiment.
As shown in FIG. 1, the projector 1 of this embodiment is a projection type image display device that displays a color image on a screen SCR. The projector 1 includes an illumination device 2 , a color separation optical system 3 , an optical modulator 4 R, an optical modulator 4 G, an optical modulator 4 B, a synthesizing 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 and a third total reflection mirror 8c, and a first It generally comprises 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 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 light (green light LG and blue light LB). On the other hand, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB, thereby separating the other light into green light LG and blue light LB.

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 behind the second dichroic mirror 7b in the optical path of the blue light LB.

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

Transmissive liquid crystal panels, for example, are used for the optical modulator 4R, the optical modulator 4G, and the optical modulator 4B. A polarizing plate (not shown) is arranged on each of the entrance side and exit side of the liquid crystal panel.

A field lens 10R, a field lens 10G, and a field lens 10B are arranged on the incident sides of the optical modulator 4R, the optical modulator 4G, and the optical modulator 4B, respectively. The field lens 10R, the field lens 10G, and the field lens 10B collimate the red light LR, the green light LG, and the blue light LB incident on the light modulator 4R, the light modulator 4G, and the light modulator 4B, respectively.

Image light from the optical modulators 4R, 4G, and 4B is incident on the combining optical system 5 . The synthesizing optical system 5 synthesizes image light corresponding to the red light LR, green light LG, and blue light LB, respectively, and emits the synthesized image light toward the projection optical system 6 . A cross dichroic prism, for example, is used for the synthesizing optical system 5 .

The projection optical system 6 consists of a group of projection lenses, 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)
Next, a lighting device 2 according to an embodiment of the invention will be described. FIG. 2 is a diagram showing a schematic configuration of the illumination device 2. As shown in FIG. 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 this embodiment, the integrator optical system 31 and the superimposing lens 33a constitute a superimposing optical system 33. As shown in FIG.

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 separating element 25, a first condensing optical system 26, a wavelength A conversion element 40 , a second retardation plate 28 b , a second condensing optical system 29 , and a diffuse reflection element 30 are provided.

Array light source 21A, collimator optical system 22, afocal optical system 23, first retardation plate 28a, polarization separation element 25, second retardation plate 28b, and second condensing optical system 29 and the diffuse reflection element 30 are arranged in order 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. are placed in The optical axis ax1 and the illumination optical axis ax2 are in the same plane and orthogonal to each other.

The array light source 21A includes a plurality of semiconductor lasers 211 as solid-state light sources. A plurality of semiconductor lasers 211 are arranged in an array in a plane perpendicular to the optical axis ax1. The semiconductor laser 211 emits, for example, a blue light beam BL (for example, a laser beam with a peak wavelength of 460 nm). The array light source 21A emits a light beam consisting of a plurality of light beams BL. In this embodiment, the array light source 21A corresponds to the "light source" in the claims.

A light beam BL emitted from the array light source 21 A 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 is composed of, for example, a plurality of collimator lenses 22a arranged in an array. A plurality of collimator lenses 22 a are arranged corresponding to a 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 luminous flux diameter of the light beam BL. The afocal optical system 23 is composed of, for example, a convex lens 23a and a concave lens 23b.

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

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

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

In addition, the polarization separation element 25 has a color separation function that allows the fluorescence YL, which has a different wavelength band from that of the light beam BL, to pass therethrough regardless of its polarization state.

The S-polarized light beam BLs emitted from the polarization separation element 25 is incident on the first condensing optical system 26 . The first condensing optical system 26 condenses the light beam BLs toward the wavelength conversion element 40 .

In this embodiment, the first condensing optical system 26 is composed of, for example, a first lens 26a and a second lens 26b. The light beam BLs emitted from the first condensing optical system 26 enters the wavelength conversion element 40 in a condensed state.

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 fluorescence YL is transmitted through the polarization separation element 25 .

On the other hand, the P-polarized light beam BLp emitted from the polarization separation element 25 is incident on the second retardation plate 28b. The second retardation plate 28b is composed of a quarter-wave plate arranged in the optical path between the polarization separation element 25 and the diffuse reflection element 30. As shown in FIG. Therefore, the P-polarized light beam BLp emitted from the polarization separation element 25 is converted, for example, into right-handed circularly polarized blue light BLc1 by the second retardation plate 28b, and then transmitted to the second condensing optical system. 29.
The second condensing optical system 29 is composed of, for example, convex lenses 29a and 29b, and causes the blue light BLc1 to enter the diffuse reflection element 30 in a condensed state.

The diffuse reflection element 30 is arranged on the opposite side of the phosphor layer 42 of the polarization separation element 25 and diffusely reflects the blue light BLc1 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 Lambertianly reflects the blue light BLc1 and does not disturb the polarization state.

The light diffusely reflected by the diffuse reflection element 30 is hereinafter referred to as blue light BLc2. According to the present embodiment, the blue light BLc2 having a substantially uniform illuminance distribution can be obtained by diffusely reflecting the blue light BLc1. For example, right-handed circularly polarized blue light BLc1 is reflected as left-handed 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 retardation plate 28b again.

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

Thereby, the blue light BLs1 is used as the illumination light WL together with the fluorescence YL that has passed through the polarization separation element 25 . That is, the blue light BLs1 and the fluorescence YL are emitted in the same direction from the polarization separating element 25, and the white illumination light WL is generated by mixing the blue light BLs1 and the fluorescence (yellow light) YL.

The illumination light WL is emitted toward the integrator optical system 31 . The integrator optical system 31 is composed of, for example, a lens array 31a and a lens array 31b. The lens arrays 31a and 31b consist of 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 is composed of a polarization separation film and a retardation plate. The polarization conversion element 32 converts the illumination light WL containing 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 homogenize the illuminance distribution of the illumination light WL in the area to be illuminated. Thus, the illumination device 2 generates 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 non-rotating fixed structure. The substrate 41 has a first surface 41a on the side of the first condensing optical system 26 and a second surface 41b on the side opposite to the first surface 41a. The wavelength conversion element 40 further includes a reflecting member 43 provided between the first surface 41a and the phosphor layer 42, and a heat dissipation member 44 provided on the second surface 41b. In this embodiment, the phosphor layer 42 corresponds to the "wavelength conversion layer" described in the claims.

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

In this embodiment, the phosphor layer 42 is held on the first surface 41a of the substrate 41 via a bonding material, which will be described later. The phosphor layer 42 converts part of the incident light into fluorescence YL and emits the fluorescence. Also, the reflecting member 43 reflects the light incident from the phosphor layer 42 toward the first condensing optical system 26 .

The heat dissipation member 44 is composed of, for example, a heat sink and has a structure having a plurality of fins. The heat dissipation member 44 is provided on the second surface 41 b of the substrate 41 opposite to the phosphor layer 42 . Note that the heat dissipation member 44 is fixed to the base material 41 by, for example, joining with metal brazing (metal joining). Since the wavelength conversion element 40 can dissipate heat through the heat dissipating member 44, the phosphor layer 42 can be prevented from being degraded by heat.

In this embodiment, the reflecting member 43 is composed of a multilayer film in which a plurality of films are laminated. FIG. 3 is a cross-sectional view showing the essential configuration of the wavelength conversion element 40. As shown in FIG. Specifically, FIG. 3 is a diagram showing a cross section of the reflecting member 43. As shown in FIG. In addition, illustration of the heat radiating member 44 is omitted in FIG. The light beams BLs emitted from the first condensing optical system 26 and incident on the phosphor layer 42 are hereinafter referred to as excitation light BLs.

As shown in FIG. 3, the phosphor layer 42 has a light incident surface 42A on which excitation light BLs is incident and fluorescence YL is emitted, and a surface opposite to the light incident surface 42A, that is, a reflecting member 43. and a bottom surface 42B provided. In this embodiment, the phosphor layer 42 corresponds to the "wavelength conversion layer" described in the claims, the light incident surface 42A corresponds to the "first surface" described in the claims, and the bottom surface 42B It corresponds to the "second surface" described in the claims.

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

The material for forming the phosphor particles may be of one type, or may be a mixture of particles formed using two or more types of materials. 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 that is an inorganic material, and phosphor particles are preferably used. Used. Alternatively, the phosphor layer may be formed by firing phosphor particles without using a binder.

The reflecting member 43 is provided on the bottom surface 42B side of the phosphor layer 42 . The phosphor layer 42 on which the reflective member 43 is formed is bonded to the substrate 41 via a bonding material 55 . As the bonding material 55, for example, nano-silver paste is used. As the bonding material 55, for example, metal bonding using metal brazing may be used.

The reflective member 43 of this embodiment includes, in order from the bottom surface 42B side of the phosphor layer 42, a multilayer film 50, a deterioration prevention film 51, a reflective layer 52, a first protective layer 53a, a second protective layer 53b, 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 at an angle equal to or larger than the critical angle of the fluorescence YL generated in the phosphor layer 42, and , and the reflection enhancing layers 50b, 50c, 50d. The increased reflection layers 50b, 50c, and 50d are intended to achieve an increased reflection effect, and improve the extraction efficiency of the fluorescence YL. The multilayer film 50 corresponds to the "first layer" described in the claims. The multilayer film 50 (total reflection layer 50 a ) is provided in contact with or stacked on the bottom surface 42 B of the phosphor layer 42 .

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

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 this embodiment, the deterioration prevention film 51 is made of a layer containing metal. The deterioration prevention film 51 is for suppressing deterioration of the reflective layer 52 as described later. The deterioration prevention film 51 corresponds to the "second layer" described in the claims.

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

The reflective layer 52 reflects a portion of the fluorescence YL generated in the phosphor layer 42 and directed toward the bottom surface 42B toward the light incident surface 42A. In addition, the reflective layer 52 reflects the excitation light BLs that has entered the phosphor layer 42 and entered the reflecting member 43 without being converted into fluorescence YL, and returns it to the inside of the phosphor layer 42 . Thereby, fluorescence YL can be efficiently generated. The reflective layer 52 corresponds to the "third layer" described in the claims.

Ag or Al was used as the material of the reflective layer 52 . In this embodiment, Ag is used as the material of the reflective layer 52 to obtain a higher reflectance. When Ag is used for the reflective layer 52, the anti-degradation film 51 contains at least one metal selected from Al, Ni, Ti, W, and Nb. Moreover, when Al is used for the reflective layer 52, the anti-degradation film 51 contains at least one metal selected from, for example, Ni, Ti, W, and Nb.

In this embodiment, the cohesive energy of the element (Ti) forming the deterioration preventing film 51 is higher than the cohesive energy of the element (Ag) forming the reflective layer 52 . Here, a large cohesive energy means that a larger energy is required to cause cohesion.

In the reflective 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 aggregation due to migration is reduced. That is, the reflective layer 52 is one in which a decrease in reflectance and a decrease in durability due to the occurrence of aggregation are suppressed. According to the reflecting member 43 of the present embodiment, since the deterioration preventing film 51 is provided, the deterioration of the reflecting layer 52 can be reduced.

The first protective layer 53 a and the second protective layer 53 b have a function of protecting the reflective layer 52 . The first protective layer 53a is made of a film containing metal. The first protective layer 53a is made of, for example, a Ni film, promotes crystallization of the reflective layer 52 (Ag film), and can improve durability.
Note that the first protective layer 53a may be formed of 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.

Also, the second protective layer 53b is composed of a layer containing an inorganic oxide. The second protective layer 53b is made of Al ₂ O ₃ , for example, and can suppress oxidation of the reflective layer 52 (Ag film) and improve adhesion with a bonding auxiliary layer 54 described later.
When SiO ₂ , TiO ₂ and Al ₂ O ₃ are used as the material of the multilayer film 50, the second protective layer 53b may be constructed using a material different from these materials.
In this embodiment, the first protective layer 53a corresponds to the "fourth layer" recited in the claims, and the second protective layer 53b corresponds to the "fifth layer" recited in the claims.

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

FIG. 4 is a cross-sectional view showing the structure of the main part of the phosphor layer 42. As shown in FIG.
As shown in FIG. 4, in this embodiment, the phosphor layer 42 has a plurality of pores 42c provided therein. As a result, the phosphor layer 42 has light scattering properties due to the plurality of pores 42c.

Since some of the plurality of pores 42c are formed on the surface (bottom surface 42B) of the phosphor layer 42, recesses 42d are formed on the bottom surface 42B of the phosphor layer 42 by the pores 42c. The wavelength conversion device 20 of this embodiment has a transparent member 45 that seals the recess 42d.

As a material for the transparent member 45, a translucent inorganic material such as alumina, _{Y3Al5O12 , YAlO3} , _zirconia dioxide _{, Lu3Al5O12} , _{SiO2 (} glass paste), or an anaerobic material may be used. An adhesive is used. In this embodiment, it is desirable to use the same material as the reflecting member 43 formed on the bottom surface 22B of the phosphor layer 42 as the material of the transparent member 45 .

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 in the same process.

As described above, the reflecting member 43 is formed by depositing a plurality of layers on the bottom surface 42B of the phosphor layer 42. As shown in FIG. Here, if the flatness of the bottom surface 42B is low, it becomes difficult to satisfactorily form each layer that constitutes the reflecting member 43 . If the reflecting member 43 cannot be satisfactorily formed on the bottom surface 42B, the fluorescent light YL cannot be reflected toward the light incident surface 42A, and the extraction efficiency of the fluorescent light YL is lowered.

On the other hand, in the wavelength conversion element 40 of the present embodiment, the recess 42d is sealed with the transparent member 45 so that the bottom surface 42B is substantially flattened. Here, the term "substantially flat surface" means flatness to the extent that the reflecting member 43 can be deposited on the bottom surface 42B by vapor deposition or the like. .

In this 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 integrally formed.

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

The baking evaporates the organic matter, and as shown in FIG. 4, a phosphor layer 42 including a plurality of pores 42c and made of 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 the phosphor layer 42 having a light incident surface 42A and a bottom surface 42B. Part of the pores 42c are exposed to the outside by grinding and polishing, and recesses 42d are formed in the bottom surface 42B of the phosphor layer 42. As shown in FIG.

Subsequently, a glass paste (SiO ₂ ) is applied to the bottom surface 42B by spin coating. As a result, the glass paste is applied to the entire surface of the bottom surface 42B while filling the recesses 42d.

By baking the glass paste, the transparent member 45 for sealing the recess 42d and the total reflection layer 50a integrally formed with the transparent member 45 are formed on the bottom surface 42B as shown in FIG. Note that the method of applying the glass paste onto the bottom surface 42B is not limited to the spin coating method, and a doctor blade method may be used.

By sealing the concave portion 42d with the transparent member 45 in this manner, the surface of the bottom surface 42B (total reflection layer 50a) can be made substantially flat. The temperature for baking the glass paste is lower than the temperature for baking the mixture of the phosphor particles and the organic matter.

Subsequently, the reflective member 43 is formed by sequentially depositing 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 laminated body of the reflecting member 43 and the phosphor layer 42 and the substrate 41 are fixed with the bonding material 55 interposed therebetween. Finally, the wavelength conversion element 40 is manufactured by fixing the heat dissipation member 44 to the surface of the substrate 41 opposite to the phosphor layer 42 .
In the manufacturing method described above, a mixture of phosphor particles and an inorganic substance that constitute the phosphor layer 42 may be prepared and the mixture may be fired at a predetermined temperature. 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 anti-deterioration film 51 suppresses deterioration due to aggregation of the reflective layer 52 made of an Ag film. Therefore, since the reflection layer 52 is unlikely to deteriorate in reflectance, the component of the fluorescence YL generated by the phosphor layer 42 that has entered the bottom surface 42B is reflected well 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 fluorescence YL.

In addition, in this embodiment, by using a Ni film as the metal film forming the first protective layer 53a that protects the reflective layer 52, crystallization of the reflective layer 52 (Ag film) is promoted and durability is improved. be able to.

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

In addition, in this embodiment, by filling the concave portion 42d of the phosphor layer 42 with the transparent member 45, the reflecting member 43 is uniformly formed over the entire bottom surface 42B. Therefore, the component of the fluorescence YL generated in the phosphor layer 42 that has entered the bottom surface 42B side is well reflected by the reflecting member 43 and emitted from the light incident surface 42A. Therefore, the extraction efficiency of fluorescence 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, heat generated in the phosphor layer 42 is efficiently transferred to the reflecting member 43 . Also, the heat generated in the phosphor layer 42 is transferred to the base material 41 and the heat dissipation member 44 through the reflecting member 43 . Therefore, the heat dissipation of the phosphor layer 42 is enhanced.

Since the heat radiation member 44 can be miniaturized by increasing the heat radiation property of the phosphor layer 42 in this way, the wavelength conversion element 40 can be miniaturized.

Further, according to the wavelength conversion element 40 of the present embodiment, the temperature rise of the phosphor layer 42 can be reduced by enhancing the heat dissipation property of the phosphor layer 42, and the deterioration of the luminous efficiency of the phosphor layer 42 can be reduced.
Therefore, the light source device 2A including this wavelength conversion element 40 can provide a light source device that suppresses a decrease in extraction efficiency of the fluorescence YL.
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-brightness image.

(Modification of first embodiment)
Next, a modification of the method for manufacturing the wavelength conversion element 40 of the first embodiment will be described. The same reference numerals are assigned to members common to those of the above-described embodiment, and detailed description thereof will be omitted.

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

The baking evaporates the organic matter, and as shown in FIG. 4, a phosphor layer 42 including a plurality of pores 42c and made of 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 the phosphor layer 42 having a light incident surface 42A and a bottom surface 42B. Part of the pores 42c are exposed to the outside by grinding and polishing, and recesses 42d are formed in the bottom surface 42B of the phosphor layer 42. As shown in FIG. 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 includes a first formation step of forming a first inorganic oxide layer on the bottom surface 42B of the phosphor layer 42 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

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

As a result, as shown in FIG. 5A, the SiO ₂ deposited by CVD forms the first total reflection layer 50a1 (SiO ₂ ). By performing film formation by CVD in this way, 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 a substantially flat surface (flat surface).

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

Subsequently, in a second forming 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.

The film thickness of the second total reflection layer 50a2 is appropriately adjusted by the other layers (increased reflection layers 50b, 50c, 50d) of the multilayer film 50 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. 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.
Further, in this modification, materials having the same main component are used to form the first total reflection layer 50a1 and the second total reflection layer 50a2. Specifically, SiO ₂ was used as the material for 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 ) in this manner, the adhesion between the first total reflection layer 50a1 and the second total reflection layer 50a2 can be enhanced. can be done.

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 reflective member 43 is formed by successively forming the bonding auxiliary layer 54 (third step, 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 laminated body of the reflecting member 43 and the phosphor layer 42 and the substrate 41 are fixed with the bonding material 55 interposed therebetween. Finally, the wavelength conversion element 40 is manufactured by fixing the heat dissipation member 44 to the surface of the substrate 41 opposite to the phosphor layer 42 .
In the manufacturing method described above, a mixture of phosphor particles and an inorganic substance that constitute the phosphor layer 42 may be prepared and the mixture may be fired at a predetermined temperature. 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 this modification, the transparent member 45 (SiO ₂ ) is formed in the recess 42d by forming the first total reflection layer 50a1 using CVD. can be formed.

In addition, in this modification, by forming the total reflection layer 50a (the first total reflection layer 50a1 and the second total reflection layer 50a2) with the same material (SiO ₂ ), the first total reflection layer 50a1 and the second total reflection layer 50a1 and the second total reflection layer 50a1 Adhesion between the layers 50a2 can be enhanced. Therefore, the effects described in the first embodiment can be further enhanced.

Further, after forming the first total reflection layer 50a1, the second total reflection layer 50a2 (SiO ₂ ) is formed by PVD. can be efficiently formed. This is because PVD can form various films such as metal films including Ag reflective films and oxide films in addition to SiO ₂ .

The material of the first total reflection layer 50a1 may not be _SiO2 . For example, SiN or SiON may be used as the material of the first total reflection layer 50a1. In this case, it is desirable to use materials having the same main component for the first total reflection layer 50a1 and the second total reflection layer 50a2. For example, when SiN is used as the material for the first total reflection layer 50a1, SiO ₂ may be used as the material for the second total reflection layer 50a2.

(Second embodiment)
Next, a wavelength conversion element according to a second embodiment of the invention will be described. The same reference numerals are assigned to members common to those of the above-described embodiment, and detailed description thereof will be omitted.

FIG. 6 is a cross-sectional view showing the essential configuration of the wavelength conversion element 140 of this embodiment. Specifically, FIG. 6 is a diagram showing a cross section of the reflecting member 143. As shown in FIG.
As shown in FIG. 6, the wavelength conversion element 140 includes a reflecting member 143 provided between the first surface 41a of the substrate 41 and the phosphor layer 42. As shown in FIG.

The reflective 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 prevention film 151, the reflective layer 52, the first protective layer 53a, the second protective layer 53b, It is configured by laminating the bonding auxiliary layer 54 .

In this embodiment, the deterioration preventing film 151 is composed of a layer containing an oxide conductive material or an amorphous conductive oxide as a translucent inorganic oxide (second inorganic oxide). The deterioration prevention film 151 is for suppressing deterioration of the reflective layer 52 as described later. The deterioration prevention film 151 corresponds to the "second layer" described in the claims.

In this embodiment, the anti-degradation film 151 is made of an oxide conductor material or an amorphous conductive oxide, such as ITO (indium tin oxide), FTO (fluorine-doped tin oxide; SnO ₂ :F), ATO (antimony-doped tin oxide; SnO2: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), oxide 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 to, for example, about 1 nm to 20 nm, more preferably about 3 to 15 nm. This is because if the film thickness is less than 1 nm, the effect of suppressing deterioration of the reflective layer 52 is reduced, and if the film thickness is greater than 20 nm, the transmittance is reduced.

That is, according to the present embodiment, the anti-deterioration film 151 having a large thickness can be formed on the reflective layer 52 within a range in which the optical transparency of the anti-deterioration film 151 is ensured. Since the reflective layer 52 is covered with the anti-degradation film 151, migration of Ag atoms due to heat is less likely to occur.

Therefore, the reflective layer 52 is reduced in occurrence of agglomeration due to migration. That is, the reflective layer 52 is one in which a decrease in reflectance and a decrease in durability due to the occurrence of aggregation are suppressed. According to the reflecting member 143 of the present embodiment, since the deterioration preventing film 151 is provided, the deterioration of the reflecting layer 52 can be reduced.

According to the wavelength conversion element 140 of the present embodiment, since the reflectance of the reflective layer 52 is unlikely to be lowered due to deterioration, the fluorescence YL generated in 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 fluorescence YL.

Since the deterioration preventing film 151 of the present embodiment has higher translucency than the deterioration preventing film 51 of the first embodiment, the film thickness range of the deterioration preventing film can be widened. That is, deterioration of the reflective layer 52 can be reduced while increasing the film thickness.

(Third embodiment)
Next, a wavelength conversion element according to a third embodiment of the invention will be described. Members common to those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 7 is a cross-sectional view showing the essential configuration of the wavelength conversion element 240 of this embodiment. Specifically, FIG. 7 is a diagram showing a cross section of the reflecting member 243. As shown in FIG.
As shown in FIG. 7, the wavelength conversion element 240 includes a reflecting member 243 provided between the first surface 41a of the substrate 41 and the phosphor layer 42. As shown in FIG.

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

In this embodiment, the first anti-deterioration film 251 and the second anti-deterioration film 252 are each made of a layer containing metal. The first anti-deterioration film 251 corresponds to the "second layer" recited in the claims, and the second anti-degradation film 252 corresponds to the "sixth layer" recited in the claims.

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

In this embodiment, the cohesive energy of the element (Ti) forming each of the first anti-degradation film 251 and the second anti-degradation film 252 is greater than the cohesive energy of the element (Ag) constituting 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 emitting side, it becomes more difficult for Ag atoms to migrate. Therefore, the occurrence of agglomeration due to migration is further reduced as compared with the configuration of the first embodiment.

According to the wavelength conversion element 240 of the present embodiment, it becomes easier to suppress a decrease in extraction efficiency of the fluorescence YL.

(Fourth embodiment)
Next, a wavelength conversion element according to a fourth embodiment of the invention will be described. Members common to those in the second embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 8 is a cross-sectional view showing the essential configuration of the wavelength conversion element 340 of this embodiment. Specifically, FIG. 8 is a diagram showing a cross section of the reflecting member 343. As shown in FIG.
As shown in FIG. 8, the wavelength conversion element 340 includes a reflecting member 343 provided between the first surface 41a of the substrate 41 and the phosphor layer 42. As shown in FIG.

The reflective 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 anti-deterioration film 351, the reflective layer 52, the second anti-deterioration film 352, and the first protective layer. 53a, a second protective layer 53b, and a bonding auxiliary layer 54 are laminated.

In this embodiment, the first anti-deterioration film 351 and the second anti-deterioration film 352 are each made of a layer containing metal. The first anti-deterioration film 351 corresponds to the "second layer" recited in the claims, and the second anti-degradation film 352 corresponds to the "sixth layer" recited in the claims.

In the present embodiment, the first anti-degradation film 351 and the second anti-degradation film 352 are made of, for example, ITO (indium tin oxide), FTO (fluorine-doped tin oxide; SnO ₂ :F), ATO (antimony _- doped tin oxide; SnO2: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 this embodiment, ITO is used as the material for the first anti-deterioration film 351 and the second anti-deterioration 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 reflective layer 52 is provided with ITO films on the light incident side and the light exit side, migration of Ag atoms is more difficult to occur. Therefore, the occurrence of agglomeration due to migration is further reduced as compared with the configuration of the second embodiment.

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

The present invention is not limited to the contents of the above-described embodiments, and can be modified as appropriate without departing from the gist of the invention.

For example, in the above embodiments, at least one metal selected from Al, Ni, Ti, W, and Nb is used as the metal-containing deterioration preventing film 51, the first deterioration preventing film 251, and the second deterioration preventing film 252. Although the contents are exemplified, the present invention is not limited to this. For example, the anti-degradation film 51, the first anti-degradation film 251 and the second anti-degradation film 252 contain at least one metal (alloy) selected from Zn—Ag alloy and Sn—Ag alloy. good too.

In the first embodiment described above, a layer made of the same material as the deterioration preventing film 51 may be arranged between the second protective layer 53b and the bonding auxiliary layer 54 made of an Ag layer.
In the second embodiment described above, a layer made of the same material as the deterioration preventing 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 either the first anti-deterioration film 251 or the second anti-deterioration film 252 is interposed between the second protective layer 53b and the bonding auxiliary layer 54 made of an Ag layer. You may arrange it.
In the fourth embodiment, a layer made of the same material as either one of the first deterioration prevention film 351 and the second deterioration prevention film 352 is provided between the second protective layer 53b and the bonding auxiliary layer 54 made of an Ag layer. You may arrange it.

Further, in the above embodiment, an example in which the light source device according to the present invention is installed in a projector has been shown, but the present invention is not limited to this. The light source device according to the present invention can also be applied to lighting fixtures, automobile headlights, and the like.

(Example)
The inventors compared Examples and Comparative Examples and conducted experiments to confirm the effectiveness of the present invention. In Example 1, a glass substrate was used instead of the phosphor, and an experiment was performed using a sample in which a reflecting member was formed on one surface of the glass substrate.

As a sample, the reflective layer constituting the reflective member is an Ag film, the deterioration prevention film is a layer made of Al, and the other layers (multilayer film, first protective layer, second protective layer and auxiliary bonding layer) are the above-described embodiments. I used the one with the same configuration as In addition, it formed so that the thickness of the deterioration prevention film might be set to about 1 nm.

In Example 2, a sample having the same structure as in Example 1 was used except that the anti-degradation film was made of Ti.
Moreover, in the comparative example, a sample having the structure of Examples 1 and 2 without the deterioration suppressing film was used.

Then, for each sample of Examples 1 and 2 and Comparative Example, light in the same wavelength band as the excitation light was applied from the other side of the glass substrate (the side opposite to the side on which the reflecting member was provided) under the condition of 40 W/mm ² . After irradiating for 15 hours, the reflectance of each reflective member (reflective layer) was measured, and the results are shown in Table 1 below. The reflectance was measured for each of three wavelengths (blue: 465 nm, green: 530 nm, red: 615 nm), and the reflectance maintenance factor was calculated. The reflectance maintenance rate is the ratio between the reflectance at the start of the experiment and the reflectance at the end of the experiment (after 15 hours have passed). That is, 100% of the reflectance maintenance rate 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 rate was less than 100% at any wavelength. On the other hand, in Examples 1 and 2, it was confirmed that the reflectance maintenance factor could be maintained at 100% at any wavelength. That is, according to Examples 1 and 2 using the deterioration suppression layer, it was confirmed that the reflective performance of the reflective layer could be maintained as compared with the comparative example. This confirms that deterioration of the reflective layer due to excitation light can be suppressed by using the deterioration suppression layer.

Further, after each sample of Examples 1 and 2 and Comparative Example was left in an environment of 350° C. for 72 hours, the reflectance by the reflecting member (reflecting layer) was measured, and the result of calculating the reflectance maintenance factor was obtained. It is shown in Table 2 below. The reflectance retention rate was calculated for each of the three wavelengths (blue: 465 nm, green: 530 nm, red: 615 nm).

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

That is, according to Examples 1 and 2 using the deterioration suppression layer, it was confirmed that the reflective performance of the reflective layer could be maintained as compared with the comparative example. From this, it was confirmed that deterioration of the reflective layer due to heat can be suppressed by using the deterioration suppression layer. Moreover, it was confirmed that the use of Ti as the deterioration suppressing layer further improved the heat resistance of the reflective layer.

DESCRIPTION OF SYMBOLS 1... Projector 2A... Light source device 4B, 4G, 4R... Light modulation device 6... Projection optical system 40, 140, 240, 340... Wavelength conversion element 41... Substrate 42... Phosphor layer (wavelength conversion layer), 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... Antidegradation film (second layer), 52... Reflective layer (third layer), 53a... First protective layer (fourth layer), 53b... second protective layer (fifth layer), 55... bonding material, 251, 351... first anti-deterioration film (second layer), 252, 352... second anti-deterioration film (sixth layer), BLs... excitation light.

Claims (20)

a wavelength conversion layer having a first surface on which excitation light is incident and a second surface facing the first surface;
a first layer provided facing the second surface and containing a first inorganic oxide containing at least SiO ₂ ;
A second layer provided opposite to the first layer and containing a second inorganic oxide different from the first inorganic oxide;
a third layer provided opposite to the second layer, containing either silver or aluminum, and reflecting the excitation light or the light obtained by wavelength conversion of the excitation light by the wavelength conversion layer;
with
The wavelength conversion layer contains pores inside,
the second surface has a recess,
A wavelength conversion element, wherein a part of the first layer is provided in the recess. The wavelength conversion element according to claim 1,
a fourth layer provided opposite to the third layer and containing a metal ;
A fifth layer provided opposite to the fourth layer and containing an inorganic oxide;
A wavelength conversion element, further comprising: The wavelength conversion element according to claim 1 or 2,
further comprising a base material,
A laminate of the wavelength conversion layer, the first layer, the second layer and the third layer and the substrate are fixed by a bonding material provided between the third layer and the substrate. A wavelength conversion element characterized by: The wavelength conversion element according to any one of claims 1 to 3,
The wavelength conversion element, wherein the second inorganic oxide of the second layer is a conductive oxide material or an amorphous conductive oxide. The wavelength conversion element according to claim 2 ,
A wavelength conversion element, further comprising a sixth layer containing a metal or an inorganic oxide between the third layer and the fourth layer. The wavelength conversion element according to claim 5 ,
The wavelength conversion element, wherein the 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 5 ,
The wavelength conversion element, wherein the inorganic oxide of the sixth layer is a conductive oxide material or an amorphous conductive oxide. a wavelength conversion layer having a first surface on which excitation light is incident and a second surface facing the first surface;
a first layer provided facing the second surface and containing a first inorganic oxide;
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;
a third layer provided opposite to the second layer, containing either silver or aluminum, and reflecting the excitation light or the light obtained by wavelength conversion of the excitation light by the wavelength conversion layer;
A second metal provided opposite to the third layer and different from the first metal or the first metal
a fourth layer containing a metal of
A fifth layer provided opposite to the fourth layer and containing an inorganic oxide;
with
The wavelength conversion layer contains pores inside,
the second surface has a recess,
A wavelength conversion element, wherein a part of the first layer is provided in the recess. The wavelength conversion element according to claim 8 ,
further comprising a base material,
A laminate of the wavelength conversion layer, the first layer, the second layer and the third layer and the substrate are fixed by a bonding material provided between the third layer and the substrate. A wavelength conversion element characterized by: The wavelength conversion element according to claim 8 or 9 ,
The wavelength conversion element, wherein the first metal of the second layer contains at least one metal selected from Al, Ni, Ti, W and Nb. The wavelength conversion element according to claim 8 or 9 ,
The wavelength conversion element, wherein the second inorganic oxide of the second layer is a conductive oxide material or an amorphous conductive oxide. The wavelength conversion element according to any one of claims 8 to 11 ,
A wavelength conversion element, further comprising a sixth layer containing the first metal or inorganic oxide between the third layer and the fourth layer. 13. The wavelength conversion element according to claim 12 ,
The wavelength conversion element, wherein the first metal of the sixth layer contains at least one metal selected from Al, Ni, Ti, W and Nb. 13. The wavelength conversion element according to claim 12 ,
The wavelength conversion element, wherein the inorganic oxide of the sixth layer is a conductive oxide material or an amorphous conductive oxide. a wavelength conversion layer having a first surface on which excitation light is incident and a second surface facing the first surface;
a first layer provided facing the second surface and containing a first inorganic oxide;
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;
a third layer provided opposite to the second layer, containing either silver or aluminum, and reflecting the excitation light or the light obtained by wavelength conversion of the excitation light by the wavelength conversion layer;
with
The wavelength conversion layer contains pores inside,
the second surface has a recess,
A portion of the first layer is provided in the recess,
The wavelength conversion element, wherein the second inorganic oxide of the second layer is a conductive oxide material or an amorphous conductive oxide. a wavelength conversion element according to any one of claims 1 to 15 ;
a light source that emits the excitation light;
A light source device comprising: A light source device according to claim 16 ;
a light modulating device that forms image light by modulating light from the light source device according to image information;
a projection optical system that projects the image light;
A projector comprising: At least Si on the second surface of the wavelength conversion layer having first and second surfaces facing each other
a _second step of forming in direct contact a first layer containing a first inorganic oxide comprising O2 ;
directly contacting the first layer with a second layer containing a first metal or a second inorganic oxide that is different from the first inorganic oxide and does not contain the first inorganic oxide; and form the third
process and
A fourth layer in which a third layer that contains either silver or aluminum and reflects the excitation light or the light whose excitation light is wavelength-converted by the wavelength conversion layer is formed in direct contact with the second layer. process and
A method for manufacturing a wavelength conversion element, comprising: a second step of forming a first layer containing a first inorganic oxide in direct contact with the second surface of the wavelength conversion layer having first and second surfaces facing each other;
a third step of forming, in direct contact with the first layer, a second layer containing a first metal or a second inorganic oxide different from the first inorganic oxide;
A fourth layer in which a third layer that contains either silver or aluminum and reflects the excitation light or the light whose excitation light is wavelength-converted by the wavelength conversion layer is formed in direct contact with the second layer. process and
with
The first layer includes a first inorganic oxide layer and a second inorganic oxide layer,
The second step includes a first forming step of forming the first inorganic oxide layer on the second surface using a chemical vapor deposition method, and a physical vapor deposition method on the first inorganic oxide layer. and a second formation step of forming a second inorganic oxide layer. A method for manufacturing a wavelength conversion element according to claim 19 ,
A method of manufacturing a wavelength conversion element, wherein _SiO2 is used as a material for the first inorganic oxide layer and the second inorganic oxide layer.

Images