Phosphor apparatus

Abstract

A phosphor device (100) is provided with: a substrate (110); a phosphor layer (120) including a plurality of pores (121); a reflective layer (130) provided between the substrate (110) and the phosphor layer (120); a bonding layer (140) that is provided between the substrate (110) and the reflective layer (130) and contains a first metal; and a metal layer (150) that is provided between the reflective layer (130) and the bonding layer (140) and contains a second metal having a higher melting point than the first metal. The reflective layer (130) has a multilayer structure in which high refractive index layers (131) and low refractive index layers (132) having a lower refractive index than the high refractive index layers (131) are alternately laminated.

Description

Technical Field

[0001] The present invention relates to phosphor devices. Background Art

[0002] Conventionally, there are known wavelength conversion elements including a phosphor that receives laser light emitted from a laser source and emits fluorescence (see, for example, Patent Documents 1 to 3). The wavelength conversion elements disclosed in Patent Documents 1 to 3 include a substrate, a phosphor layer, and a reflective layer disposed between the substrate and the phosphor layer.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6536212

[0006] Patent Document 2: Japanese Patent Application Publication No. 2022-41839

[0007] Patent Document 3: Japanese Patent No. 6499381 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the above-mentioned conventional technology, there is room for improvement in the reliability of supporting the reflective layer and the phosphor layer by the substrate.

[0010] Therefore, an object of the present invention is to provide a phosphor device having high reliability.

[0011] Means used to solve problems

[0012] A phosphor device according to a technical solution of the present invention comprises: a substrate; a phosphor layer comprising a plurality of pores; a first reflective layer arranged between the substrate and the phosphor layer; a bonding layer arranged between the substrate and the first reflective layer and comprising a first metal; and a metal layer arranged between the first reflective layer and the bonding layer and comprising a second metal having a higher melting point than the first metal; the first reflective layer has a multilayer structure in which a high refractive index layer and a low refractive index layer having a lower refractive index than the high refractive index layer are alternately stacked.

[0013] Effects of the Invention

[0014] According to the present invention, a highly reliable phosphor device can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a cross-sectional view of the phosphor device according to Embodiment 1.

[0016] Figure 2This is a diagram showing a cross-sectional SEM image of a phosphor layer of the phosphor device according to Embodiment 1.

[0017] Figure 3 This is a diagram showing a cross-sectional SEM image of a bonding layer of the phosphor device according to Embodiment 1.

[0018] Figure 4 This is an image obtained by binarizing a cross-sectional SEM image of the phosphor layer of the phosphor device according to Embodiment 1.

[0019] Figure 5 This is a graph showing the relationship between the porosity and density of the phosphor layer.

[0020] Figure 6 This is a diagram for explaining the reliability of the phosphor device according to the first embodiment.

[0021] Figure 7 This is a cross-sectional view of a phosphor device according to Embodiment 2.

[0022] Figure 8 This is a diagram showing the incident angle dependency of the reflectance of the phosphor device according to the second embodiment due to the stacked structure of the first reflecting layer and the second reflecting layer.

[0023] Fig. 9 It is a diagram for explaining the stress relaxation effect brought about by the first reflecting layer in the phosphor device according to each embodiment. DETAILED DESCRIPTION

[0024] Hereinafter, the phosphor device according to the embodiment of the present invention will be described in detail using the accompanying drawings. In addition, the embodiments described below all represent a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, configurations and connection forms of components, steps, and the order of steps shown in the following embodiments are examples and are not intended to limit the present invention. Therefore, regarding the components of the following embodiments that are not described in the independent claims, they are described as arbitrary components.

[0025] In addition, each figure is a schematic diagram and does not necessarily illustrate the figure strictly. Therefore, for example, the scales in each figure are not necessarily the same. In addition, in each figure, the same reference numerals are given to substantially the same structure, and repeated descriptions are omitted or simplified.

[0026] In addition, in this specification, terms such as parallel that indicate the relationship between elements, and terms such as circular or rectangular that indicate the shape of elements, and numerical ranges do not express only strict meanings, but mean essentially the same range, for example, also including differences of several percentage points.

[0027] In addition, in this specification, the terms "above" and "below" do not refer to the above (vertically above) and below (vertically below) in absolute spatial identification, but are used as terms specified by relative positional relationships based on the stacking order in the stacking structure. In the following description, the direction in which the phosphor layer is located relative to the substrate is regarded as "above", and the opposite side is regarded as "below". In addition, the terms "above" and "below" are not only applicable to the case where two components are arranged at a distance from each other and there is another component between the two components, but also to the case where two components are arranged in close contact with each other, so that the two components are connected.

[0028] In addition, in this specification, "A contains B as a main component" means that the content of B contained in A is greater than 50%. In this case, the content of B may be 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, 99% or more, or 100%. In addition, when the content of B contained in A is 100%, A may also contain inevitable impurities that cannot be avoided in the production process. That is, "content 100%" means that the purity of B is so high that it can be regarded as 100% in essence.

[0029] In the present specification, ordinal numbers such as “first” and “second” do not refer to the number or order of components unless otherwise specified, but are used to avoid confusion between the same components or to distinguish them.

[0030] (Implementation Method 1)

[0031] [structure]

[0032] First, use Figure 1 The outline of the phosphor device according to Embodiment 1 is described below. Figure 1 It is a cross-sectional view of the phosphor device 100 according to the present embodiment.

[0033] Figure 1 The phosphor device 100 shown includes a phosphor that emits fluorescence when excited by light from an excitation light source (not shown). The phosphor device 100 is used, for example, as a light source unit (light-emitting unit) of a projector or lighting device. For example, an optical system (not shown) such as a lens and an aperture is arranged on the fluorescence emission side of the phosphor device 100. Thus, the fluorescence or the reflected light of the fluorescence and the excitation light can be emitted in a desired direction via the optical system.

[0034] In addition, the excitation light source is, for example, a semiconductor laser element or an LED (Light Emitting Diode), but is not limited thereto. As an example, the excitation light source is a blue laser element that emits blue light. In addition, the excitation light may be visible light other than blue light (for example, violet light), or ultraviolet light.

[0035] like Figure 1 As shown, the phosphor device 100 includes a substrate 110, a phosphor layer 120, a reflective layer 130, a bonding layer 140, a metal layer 150, a protective layer 160, and an anti-reflection film 170. The bonding layer 140, the metal layer 150, the protective layer 160, the reflective layer 130, the phosphor layer 120, and the anti-reflection film 170 are stacked in this order from the substrate 110 side. In addition, the protective layer 160 and the anti-reflection film 170 may not be provided.

[0036] The substrate 110 is a supporting member that supports the phosphor layer 120. In addition, the substrate 110 also functions as a heat dissipation member (heat sink) that dissipates heat generated when the substrate 110 is irradiated with excitation light. For example, the substrate 110 is formed using a material with high thermal conductivity. As a result, the heat dissipation of the substrate 110 can be improved, so the wavelength conversion efficiency of the phosphor layer 120 can be improved, and the reliability can be improved. The material with high thermal conductivity is, for example, a metal such as copper (Cu). For example, a copper plate with a laminated film of gold (Au) and nickel (Ni) plated on the surface can be used as the substrate 110.

[0037] The phosphor layer 120 is excited by the excitation light and emits fluorescence. In the present embodiment, the phosphor layer 120 includes a yellow phosphor that emits yellow light when receiving blue light as the excitation light. The yellow phosphor is a phosphor whose peak wavelength in the excitation spectrum is in the range of 380 nm to 490 nm and whose peak wavelength in the fluorescence spectrum is in the range of 490 nm to 580 nm. The phosphor device 100 can emit white light as a mixture of yellow light emitted from the yellow phosphor and blue light as the excitation light.

[0038] As an example, the yellow phosphor is a cerium-activated garnet structure phosphor, such as YAG, but is not limited to this. In addition, the type of phosphor contained in the phosphor layer 120 is, for example, one, but is not limited to this. The phosphor layer 120 may include a plurality of phosphors. For example, the phosphor layer 120 may also include at least one of a green phosphor and a red phosphor in addition to or instead of the yellow phosphor. For example, the phosphor layer 120 may also include a green phosphor such as LuAG, or a red phosphor such as CASN or SCASN. By adjusting the type of phosphor contained in the phosphor layer 120, the phosphor device 100 can emit light of a desired color.

[0039] In this embodiment, the phosphor layer 120 is a sintered body of phosphor, that is, ceramic. Figure 1 (a) and Figure 2 As shown, the phosphor layer 120 includes a plurality of pores (air bubbles) 121 .

[0040] here, Figure 1 (a) schematically shows an enlarged cross section of the vicinity of the interface between the phosphor layer 120 and the reflective layer 130 . Figure 2 FIG. 1 is a diagram showing a cross-sectional SEM (Scanning Electron Microscope) image of the phosphor layer 120 of the phosphor device 100 according to the present embodiment. Figure 2 As shown, a plurality of pores 121 are dispersed in the phosphor layer 120 .

[0041] The presence of the pores 121 can scatter the excitation light incident on the phosphor layer 120 and the generated fluorescence. The ratio of the pores 121 to the phosphor layer 120 (hereinafter referred to as porosity) is, for example, 1% to 9%. The method of measuring the porosity will be described later.

[0042] If the pores 121 do not exist at all, the phosphor layer 120 will function like a light guide plate, and the light-emitting point (spot) will be greatly expanded. By making the porosity greater than 1%, the expansion of the light-emitting point can be suppressed by properly scattering the light. As a result, the light incidence efficiency of the fluorescence emitted from the light-emitting point to the optical system (not shown) (i.e., the light intake efficiency in the optical system) can be improved. In addition, by making the porosity less than 9%, it is possible to fully ensure the fluorescent material that emits fluorescence, so the decrease in luminous efficiency can be suppressed. In this way, by adjusting the porosity, it is possible to take into account both the increase in the light incidence efficiency to the optical system and the suppression of the decrease in luminous efficiency.

[0043] The area of ​​the main surface of the phosphor layer 120 (the surface parallel to the main surface of the substrate 110) is 1.5 mm as an example. 2 Above and 36mm 2 For example, in an area of ​​1.5 mm 2 In the above case, the expansion of the light-emitting point is not limited, and a light-emitting point of a certain size or larger can be ensured. As a result, the heat dissipation area to the back side of the phosphor layer 120 (the side on the substrate 110 side) can also be ensured to be large, so the heat dissipation can be improved. In addition, by making the area of ​​the main surface of the phosphor layer 120 36mm 2In this way, it is possible to suppress excessive expansion of the light-emitting point. As a result, it is possible to improve the light incidence efficiency of the fluorescence emitted from the light-emitting point to the optical system (not shown) (i.e., the light intake efficiency of the optical system). In this way, by adjusting the area of ​​the main surface of the phosphor layer 120, it is possible to achieve both improvement in heat dissipation and improvement in light incidence efficiency to the optical system.

[0044] The plan view shape of the main surface of the phosphor layer 120 is, for example, a circle, but is not limited thereto. The plan view shape of the main surface of the phosphor layer 120 may be a rectangle such as a square or a rectangle, or a ring shape of a predetermined width.

[0045] The thickness t1 of the phosphor layer 120 is, for example, not less than 20 μm and not more than 150 μm. By setting the thickness t1 to be not less than 20 μm, the mechanical strength of the phosphor layer 120 can be improved. In addition, by setting the thickness t1 to be not more than 150 μm, the distance between the light incident surface (the surface on the anti-reflection film 170 side) of the phosphor layer 120 and the substrate 110 can be shortened, so that the heat generated near the light incident surface can be efficiently transferred to the substrate 110. Therefore, the heat dissipation of the phosphor layer 120 can be improved. In addition, by setting the thickness t1 to be not more than 150 μm, the excessive expansion of the light emitting point can be suppressed. As a result, the light incident efficiency of the fluorescence emitted from the light emitting point to the optical system (not shown) (that is, the light intake efficiency in the optical system) can be improved. In this way, by adjusting the thickness t1 of the phosphor layer 120, it is possible to achieve improved mechanical strength, improved heat dissipation, and improved light incident efficiency to the optical system.

[0046] Although in Figure 1 and Figure 2 Although not shown in the figure, a phosphor smaller in size than the phosphor constituting the main body of the phosphor layer 120 may be placed in the concave portion existing on the main surface of the phosphor layer 120. In this way, the flatness of the main surface of the phosphor layer 120 can be improved. By improving the flatness, the film formation quality of the anti-reflection film 170 and the reflection layer 130 can be improved. In this way, the transmittance of the anti-reflection film 170 and the reflectance of the reflection layer 130 can be improved.

[0047] In addition, in the present embodiment, the phosphor layer 120 may not contain an adhesive such as a binder.

[0048] The reflective layer 130 is an example of a first reflective layer, and is provided between the substrate 110 and the phosphor layer 120. Specifically, the reflective layer 130 is in contact with the phosphor layer 120. More specifically, the reflective layer 130 is in contact with and covers substantially the entire main surface of the phosphor layer 120 on the substrate 110 side. Thus, the adhesion between the reflective layer 130 and the phosphor layer 120 can be improved, and the peeling of the reflective layer 130 can be suppressed, and the reliability of the phosphor device 100 can be improved.

[0049] The reflective layer 130 reflects the fluorescence emitted from the fluorescent layer 120. In addition, the reflective layer 130 reflects the excitation light after passing through the fluorescent layer 120. Figure 1 As shown in (b), the reflective layer 130 has a multilayer structure in which high refractive index layers 131 and low refractive index layers 132 are alternately stacked. Figure 1 (b) schematically shows an enlarged cross-sectional structure of the reflective layer 130. In the present embodiment, the high refractive index layers 131 and the low refractive index layers 132 are alternately stacked in close contact with each other.

[0050] The high refractive index layer 131 is a layer having a higher refractive index than the low refractive index layer 132. Specifically, the high refractive index layer 131 is formed using a dielectric material having a high refractive index.

[0051] The high refractive index layer 131 is, for example, a Nb2O5 layer, which contains niobium oxide (Nb2O5) as a main component. The refractive index of the Nb2O5 layer is about 2.3. The melting point of Nb2O5 is lower than that of other high refractive oxide materials (such as TiO2 and Ta2O5). Therefore, it is not easy to be distorted during film formation by evaporation method, etc., and a high refractive index layer 131 with excellent film quality can be formed. As a result, the optical properties of the reflective layer 130 (such as the design accuracy of the reflectivity and the reflection wavelength) can be improved. In addition, the high refractive index layer 131 can also be a layer containing TiO2 or Ta2O5 as a main component.

[0052] The low refractive index layer 132 is a layer having a lower refractive index than the high refractive index layer 131. Specifically, the low refractive index layer 132 is formed using a dielectric material having a low refractive index.

[0053] The low refractive index layer 132 is, for example, a SiO2 layer containing silicon oxide (SiO2) as a main component. The refractive index of the SiO2 layer is about 1.5. Alternatively, the low refractive index layer 132 may be a layer containing MgF2 or CaF2 as a main component.

[0054] In this embodiment, if Figure 1 As shown in (a), the low refractive index layer 132 is located at the uppermost layer of the reflective layer 130 and is in contact with the phosphor layer 120. The low refractive index layer 132 located at the uppermost layer functions as a planarization layer 133 that is thicker than other low refractive index layers 132. By providing the planarization layer 133, the surface unevenness of the phosphor layer 120 can be alleviated, and the film quality (e.g., flatness) of the high refractive index layer 131 and the low refractive index layer 132 can be improved.

[0055] By adjusting the materials (refractive index), thickness and number of layers of the high refractive index layer 131 and the low refractive index layer 132, the reflectivity and wavelength range of the reflection of the reflection layer 130 can be adjusted. In this embodiment, the reflection layer 130 is configured to efficiently reflect blue light (excitation light) and yellow light (fluorescence). The reflection layer 130 can also efficiently reflect light throughout the entire visible light range.

[0056] The total number of high refractive index layers 131 and low refractive index layers 132 is 3 or more. The total number of layers may be, for example, 10 or more, 20 or more, 30 or more, 40 or more, or 50 or more.

[0057] In the present embodiment, the thickness t2 of the reflective layer 130 is 1.0% or more of the thickness t1 of the phosphor layer 120. Thus, the mechanical strength of the reflective layer 130 can be improved, and peeling of the layer can be suppressed. In addition, the thickness t2 of the reflective layer 130 is less than 10% of the thickness t1 of the phosphor layer 120. By making the reflective layer 130 not too thick, stress can be suppressed, and peeling or warping of the phosphor layer 120 can be reduced.

[0058] The thickness t2 of the reflective layer 130 is, for example, greater than 500 nm and less than 8000 nm. By making the thickness t2 greater than 500 nm, the mechanical strength of the reflective layer 130 can be improved. In addition, peeling at the interface with the phosphor layer 120 can be suppressed. In addition, the surface unevenness of the phosphor layer 120 can be eased, and the film quality (for example, flatness) of the high refractive index layer 131 and the low refractive index layer 132 can be improved. In addition, the diffusion of the metal material contained in the bonding layer 140 can be suppressed. In this way, by making the thickness t2 greater than 500 nm, the reliability of the phosphor device 100 can be improved. The thickness t2 can also be greater than 1500 nm. As a result, the effects of improving mechanical strength, suppressing peeling, improving film quality, and suppressing the diffusion of metal materials can be better exerted.

[0059] Furthermore, by making the thickness t2 of the reflective layer 130 less than 8000 nm, the heat generated by the phosphor layer 120 can be efficiently transferred to the substrate 110. Therefore, it is possible to improve the heat dissipation of the phosphor layer 120. In this way, by adjusting the thickness t2 of the reflective layer 130, it is possible to achieve improvement in mechanical strength, improvement in reliability, and improvement in heat dissipation.

[0060] The bonding layer 140 is provided between the substrate 110 and the reflective layer 130. Specifically, the bonding layer 140 is in contact with the main surface of the substrate 110 on the phosphor layer 120 side. The bonding layer 140 is provided to bond the phosphor layer 120 and the reflective layer 130 to the substrate 110.

[0061] The bonding layer 140 includes a first metal. Specifically, the bonding layer 140 includes the first metal as a main component. The bonding layer 140 has a single layer structure of the first metal. The first metal is silver (Ag) or copper (Cu).

[0062] Figure 3 FIG. 1 is a diagram showing a cross-sectional SEM image of the bonding layer 140 of the phosphor device 100 according to the present embodiment. Figure 3 As shown, there are many pores. In addition, Figure 3 The black spots in the pores correspond to the pores. The effects brought about by the bonding layer 140 including the pores will be described later.

[0063] The metal layer 150 is provided between the reflective layer 130 and the bonding layer 140. In the present embodiment, the metal layer 150 is provided between the protective layer 160 and the bonding layer 140. The metal layer 150 is in contact with the main surface of the bonding layer 140 on the phosphor layer 120 side.

[0064] The metal layer 150 includes a second metal. Specifically, the metal layer 150 includes the second metal as a main component. The second metal is a metal having a higher melting point than the first metal. For example, the second metal is chromium (Cr), nickel (Ni), palladium (Pd) or tungsten (W). The metal layer 150 may have a stacked structure of a plurality of different metal layers or a single layer structure. The metal layer 150 may be a single body of the second metal or an alloy with other metal elements.

[0065] The metal layer 150 is a layer for assisting the bonding performed by the bonding layer 140. Specifically, by making the metal layer 150 contain a second metal having a higher melting point than the first metal, the adhesion between the bonding layer 140 and the protective layer 160 (or the reflective layer 130 in the absence of the protective layer 160) can be improved. In addition, the metal layer 150 also functions as an isolation metal (metal protection layer) that inhibits the diffusion of the first metal from the bonding layer 140. On the other hand, the metal layer 150 also functions as an isolation metal that inhibits impurities such as oxygen from entering the bonding layer 140.

[0066] Protective layer 160 is provided between reflective layer 130 and metal layer 150. Protective layer 160 is in contact with the principal surface of reflective layer 130 on the substrate 110 side and the principal surface of metal layer 150 on the phosphor layer 120 side, respectively.

[0067] The protective layer 160 is a layer containing a dielectric material as a main component. For example, the protective layer 160 contains aluminum oxide (Al2O3) or silicon oxide (SiO2). The protective layer 160 may also be a single-layer structure of a dielectric layer or a stacked structure of multiple dielectric layers. The stacked structure may also include a metal layer, etc.

[0068] By providing the protective layer 160, stress caused by the difference in thermal expansion coefficient between the reflective layer 130 and the metal layer 150 can be alleviated, and peeling of the layers can be suppressed. In addition, the protective layer 160 can suppress the diffusion of the first metal from the bonding layer 140 into the reflective layer 130. In addition, the protective layer 160 can suppress the film quality of the reflective layer 130 from changing due to the entry of oxygen and ions into the reflective layer 130. Thus, a decrease in reliability such as a decrease in reflectivity can be suppressed.

[0069] The anti-reflection film 170 is an AR coating for suppressing reflection of excitation light from an excitation light source (not shown). The anti-reflection film 170 has a high transmittance for excitation light and fluorescence. The anti-reflection film 170 contacts and covers the main surface of the phosphor layer 120 on the opposite side of the substrate 110. The anti-reflection film 170 has, for example, a single-layer structure or a stacked structure of a dielectric layer. The dielectric layer included in the anti-reflection film 170 is, for example, a TiO2 layer, a Nb2O5 layer, a SiO2 layer, etc., but is not limited thereto.

[0070] [Pores in phosphor layer]

[0071] Next, use Figure 4 A method for measuring the porosity of phosphor layer 120 will be described. Figure 4 This is an image obtained by binarizing a cross-sectional SEM image of the phosphor layer 120 .

[0072] The porosity is calculated as the ratio of the total area of ​​the pores 121 present in the cross section of the phosphor layer 120 to the cross-sectional area of ​​the cross section of the phosphor layer 120. Specifically, Figure 4 As shown, an SEM image of an arbitrary cross section of the phosphor layer 120 is binarized by image processing. This makes it easy to distinguish the pores 121 from the main part (phosphor part) of the phosphor layer 120. By calculating the cross-sectional area of ​​the phosphor layer 120 (including the total area of ​​the phosphor and the pores 121) and the total area of ​​the pores 121 in the binarized image, the porosity can be calculated.

[0073] In order to suppress the variation in the calculated porosity, a value obtained by averaging the porosities calculated in a plurality of cross sections may be calculated as the porosity of the phosphor layer 120 .

[0074] Figure 5 Graph showing the relationship between porosity and density of the phosphor layer 120. Figure 5 The horizontal axis represents density (unit: g / cm 3 ), the vertical axis represents the porosity (unit: %). Figure 5 As shown, it can be seen that the porosity and density have a negative correlation.

[0075] Figure 5Each plot shown shows the measured values ​​of the porosity and density of samples 1 to 3 of the phosphor layer 120 produced by the inventors of the present application. Table 1 shows the specific values ​​of the porosity and density.

[0076] [Table 1]

[0077]

[0078] Sample 3 shows the result of calculating the porosity in four different cross sections. As shown in Table 1, it can be seen that although there is a deviation between 1.82% and 2.06%, the porosity decreases when the density is high compared to Samples 1 and 2.

[0079] Therefore, the porosity value can be estimated from the density of the phosphor layer 120. For example, the density of the phosphor layer 120 according to the present embodiment is 3.80 g / cm 3 Above and 4.55g / cm 3 the following.

[0080] [Porosity in the bonding layer]

[0081] Next, the effects of the pores present in the bonding layer 140 will be described.

[0082] like Figure 3 As shown, there are many pores in the bonding layer 140. Generally, if there are many large pores in the bonding layer 140, the mechanical bonding strength decreases and the heat dissipation decreases. For example, in the case where the phosphor device 100 related to the present embodiment is used in a device excited by laser irradiation, since it is a non-rotational type, there is no cooling effect caused by rotation, so it becomes important to efficiently dissipate the heat generated from the phosphor layer 120 from the bonding layer 140 to the substrate 110. In this case, by reducing the proportion of pores in the bonding layer 140, the heat dissipation can be improved, and the limit value of the blue laser power that can be input can be increased. By increasing the limit value of the blue laser power that can be input, high light output can be obtained.

[0083] In the phosphor device 100 according to the present embodiment, the porosity of the bonding layer 140 is 20% or less. By setting the porosity of the bonding layer 140 to 20% or less, high heat dissipation is achieved. By improving the heat dissipation, even if the thickness of the phosphor layer 120 is set thick and the heat generated by the phosphor layer 120 increases, the light conversion efficiency is not easily reduced due to the temperature characteristics of the phosphor, and the film thickness range of the phosphor layer 120 can be set large. By making the thickness of the phosphor layer 120 thick, the absorption rate of the blue laser can be increased, the light conversion efficiency can be improved, and a high light output can be obtained.

[0084] Figure 61 is a diagram for explaining the reliability of the phosphor device 100 according to the present embodiment. Figure 6 In FIG. 1 , the horizontal axis represents the elapsed time (unit: h) from the start of laser irradiation, and the vertical axis represents the maintenance rate of the fluorescent output of the fluorescent device.

[0085] Figure 6 The figure shows the change in the fluorescence output of the phosphor device when the sample of the phosphor device 100 with a porosity of 20% in the bonding layer 140 is continuously irradiated with a blue laser. The vertical axis shows the fluorescence output maintenance rate when the fluorescence output of the phosphor device in the initial state (at the start of laser irradiation) is set to 100%. Figure 6 As shown in FIG. 1 , even after 500 hours, the maintenance rate is about 99%. In other words, it can be seen that the phosphor device 100 with a long life and high reliability is realized.

[0086] In addition, the relationship between the thickness of the bonding layer 140 and the input limit power is described using Table 2. Table 2 shows the relative values ​​of the thickness of the bonding layer 140 with a porosity of 20% and the input limit power. In addition, the relative value shows the input limit power when the input limit power when the thickness of the bonding layer 140 in the initial state is 30 μm is set to 100%.

[0087] As shown in Table 2, in the region where the thickness of the bonding layer 140 is 30 μm or more and 125 μm or less, no decrease in the input limit power is observed. If the thickness of the bonding layer 140 exceeds 150 μm, a decrease in the input limit power is observed. In addition, by making the bonding layer 140 thick, the effect of buffering the stress on the phosphor layer 120 can be obtained, and the rupture of the phosphor layer 120 can be prevented.

[0088] [Table 2]

[0089]

[0090] (Implementation Method 2)

[0091] Next, embodiment 2 will be described.

[0092] The phosphor device according to Embodiment 2 is different from Embodiment 1 in that it includes a second reflective layer. The following description will focus on the differences from Embodiment 1, and the description of the common points will be omitted or simplified.

[0093] Figure 7 FIG. 2 is a cross-sectional view of a phosphor device 200 according to the present embodiment. Figure 7 As shown, the phosphor device 200 is different from the phosphor device 100 according to the first embodiment in that it further includes a reflective layer 230 .

[0094] The reflective layer 230 is an example of a second reflective layer, and has a different reflective property from that of the reflective layer 130. The reflective layer 230 is disposed between the reflective layer 130 and the bonding layer 140. Specifically, the reflective layer 230 is disposed between the reflective layer 130 and the metal layer 150. More specifically, the reflective layer 230 is disposed between the reflective layer 130 and the protective layer 160. For example, the upper surface of the reflective layer 230 is in contact with the lower surface of the reflective layer 130, and the lower surface of the reflective layer 230 is in contact with the upper surface of the protective layer 160. The thickness of the reflective layer 230 is not particularly limited, and is, for example, not less than 10 nm and not more than 1500 nm.

[0095] The reflective layer 230 is a metal reflective layer containing a metal as a main component. Specifically, the reflective layer 230 is a layer composed of a metal monomer or an alloy of a metal material such as Ag, Al, Rh, Pd, Cr, Sn, Zn, etc. For example, the reflective layer 230 is an APC (alloy of Ag, Pd and Cu) mirror layer. When the APC mirror layer is used as the reflective layer 230, high reflectivity and high corrosion durability can be achieved.

[0096] In addition, the reflective layer 230 may also be a multilayer of the above-mentioned metal monomer or alloy, or may be a mixed structure with a metal oxide such as Al2O3, SnOx, or ZnOx by oxidizing the above-mentioned metal monomer. For example, (ZnO / Zn mixed layer) / Ag, (SnO / Sn mixed layer) / Ag may be considered as the reflective layer 230. Furthermore, the reflective layer 230 may also be a structure such as (Al2O3 / Al mixed layer) / (ZnO / Zn mixed layer) / Ag, (Al2O3 / Al mixed layer) / (SnO / Sn mixed layer) / Ag. By making it a multilayer structure, reliability is improved.

[0097] The phosphor device 200 according to the present embodiment can efficiently reflect light incident from an oblique direction by having a stacked structure of the reflective layers 130 and 230. That is, the reflective layers 130 and 230 are provided to suppress the incident angle dependency of the reflectivity and to achieve a stable reflectivity.

[0098] Generally, the excitation light for exciting the phosphor layer 120 is incident on the phosphor device 200 at a relatively small incident angle. Here, the incident angle is an incident angle relative to the upper surface (interface with the anti-reflection film 170) of the phosphor layer 120. For example, the excitation light is incident on the phosphor layer 120 at an incident angle of less than 10°.

[0099] However, if Figure 2As shown, the phosphor layer 120 includes a plurality of pores 121, so even the excitation light incident at a relatively small incident angle is reflected in various directions while propagating in the phosphor layer 120. Therefore, there is a case where the excitation light is incident on the reflective layer 130 at a relatively large incident angle. The same is true for the fluorescence generated in the phosphor layer 120.

[0100] Here, use Figure 8 The incident angle dependency of the reflectivity of the reflective layer 130 will be described. Figure 8 This is a diagram showing the incident angle dependency of the reflectance of the stacked structure of the reflecting layers 130 and 230 of the phosphor device 200 according to the present embodiment.

[0101] Figure 8 The six graphs shown represent the wavelength dependence of the reflectance of the three samples of Example 1, Example 2 and Comparative Example 1. The six graphs respectively represent the cases where the incident angles of the light irradiated on each sample are 5°, 15°, 25°, 35°, 45°, and 55°. Example 1 is a structure in which a reflective layer 130 is formed on a white glass substrate (equivalent to Embodiment 1). Example 2 is a structure in which a reflective layer 130 and a reflective layer 230 are stacked on a white glass substrate (equivalent to Embodiment 2). Comparative Example 1 is a structure in which a reflective enhancement layer and a reflective layer 230 are stacked on a white glass substrate. In addition, the reflective enhancement layer is a structure in which 4 to 5 layers of high refractive index layers and low refractive index layers are stacked. In each sample, the phosphor layer 120 is not formed.

[0102] according to Figure 8 It can be seen that regardless of the incident angle, in the range of about 430 nm to about 650 nm, the reflectances of Examples 1 and 2 are maintained higher than that of Comparative Example 1. That is, high reflectance is achieved by a single reflective layer 130 or a stacked structure of reflective layers 130 and 230 .

[0103] On the other hand, in the long wavelength region, the reflectance of Example 1 tends to decrease as the incident angle increases. For example, when the incident angle is 55°, the reflectance of Example 1 decreases in the range of about 650 nm or more.

[0104] In contrast, in Example 2, it is found that the reflectivity slightly decreases when the incident angle increases, but the reflectivity is maintained higher than that of Example 1. That is, it is found that by providing the reflective layer 230 in addition to the reflective layer 130 , the reflective layer 230 can reflect light of a wavelength component that is not reflected by the reflective layer 130 .

[0105] Therefore, in the phosphor device 200 according to the present embodiment, the incidence angle dependency of the reflectance can be suppressed, and a high reflectance can be maintained in the visible light range.

[0106] (Stress relief)

[0107] Here, the stress relaxation effect by the reflective layer 130 of the phosphor devices 100 and 200 according to the first and second embodiments will be described.

[0108] like Figure 1 and Figure 7 As shown, the phosphor devices 100 and 200 are provided with a flattening layer 133 on the lower surface side of the phosphor layer 120. The flattening layer 133 can smooth the unevenness of the surface of the phosphor layer 120 and improve the film quality (e.g., flatness) of the high refractive index layer 131 and the low refractive index layer 132. In addition, the flattening layer 133 is a part of the reflective layer 130. In other words, the flattening layer 133 is the layer closest to the phosphor layer 120 (specifically, the uppermost layer) in the multilayer structure of the reflective layer 130.

[0109] The planarization layer 133 is formed thicker than the other low refractive index layers 132 to alleviate the unevenness of the surface of the phosphor layer 120. Therefore, in order to improve the reliability of the phosphor devices 100 and 200, it is necessary to alleviate the stress caused by the planarization layer 133. The stress is alleviated by the multilayer structure of the reflective layer 130.

[0110] Fig. 9 1 is a diagram for explaining the stress relaxation effect of the reflective layer 130 in the phosphor devices 100 and 200 according to the embodiments. Fig. 9 , the bonding state between the phosphor layer 120 and the substrate 110 and the measurement results of the surface irregularities of the phosphor layer 120 are shown for three samples of Comparative Example 2, Example 3, and Example 4.

[0111] Comparative Example 2 is a structure in which a silicon oxide film with a thickness of 1 μm is provided instead of the reflective layer 130. Example 3 is a structure in which a multilayer structure of a Nb2O5 layer and a SiO2 layer is formed with a thickness of 3 μm as the reflective layer 130 (equivalent to Embodiment 1). Example 4 is a structure in which a multilayer structure of a Nb2O5 layer and a SiO2 layer with a thickness of 1 μm and a Ag thin film are formed as the reflective layers 130 and 230 (equivalent to Embodiment 2).

[0112] Fig. 9 The bonding state shown is a photograph of each sample taken from the front. In Comparative Example 2, the end of the sample is peeled off (white part). That is, it can be seen that the adhesion between the phosphor layer 120 and the substrate 110 is not fully ensured in Comparative Example 2. In contrast, in Examples 3 and 4, the stress is relieved by the multilayer structure, and as a result, the peeling of the phosphor layer 120 is almost not seen, ensuring high adhesion.

[0113] Fig. 9The surface unevenness shown represents the result of measuring the surface height of each sample by a VR meter. The height of the surface is represented by the depth of gray. In the comparative example, there is a tendency for the height to be different between the upper side and the lower side, and it can be seen that warping has occurred. In addition, in Example 3, there is a tendency for the height to be different near the center and the four corners, and it can be seen that warping has occurred. That is, when the multilayer structure is made too thick, although the adhesion can be ensured, warping occurs. On the other hand, in Example 4, the height is averaged as a whole, and it can be seen that no warping has occurred. In this way, by using the reflective layer 130 composed of a multilayer structure and the reflective layer 230 of a metal film, it is possible to take into account both ensuring adhesion and reducing warping.

[0114] (Summarize)

[0115] As described above, the phosphor device according to the first technical solution of the present invention is, for example, the phosphor device 100 or 200 described above, and includes: a substrate 110; a phosphor layer 120 including a plurality of pores 121; a reflective layer 130 disposed between the substrate 110 and the phosphor layer 120; a bonding layer 140 disposed between the substrate 110 and the reflective layer 130 and including a first metal; and a metal layer 150 disposed between the reflective layer 130 and the bonding layer 140 and including a second metal having a higher melting point than the first metal. The reflective layer 130 has a multilayer structure in which a high refractive index layer 131 and a low refractive index layer 132 having a lower refractive index than the high refractive index layer 131 are alternately stacked.

[0116] As a result, the adhesion between the bonding layer 140 and the metal layer 150 is improved, so that the phosphor layer 120 and the reflective layer 130 are not easily peeled off from the substrate 110. As described above, according to the present invention, it is possible to provide a phosphor device 100 or 200 with high reliability.

[0117] Furthermore, for example, in the phosphor device according to the second aspect of the present invention, in the phosphor device according to the first aspect, the phosphor layer 120 is ceramic.

[0118] Thus, it is possible to easily form the phosphor layer 120 including a plurality of pores 121. Since the pores 121 function as light scattering elements, it is possible to suppress the lateral propagation of light in the phosphor layer 120. Therefore, it is possible to suppress the expansion of the light emitting point and improve the light incident efficiency to the optical system (not shown).

[0119] Furthermore, for example, in the phosphor device according to the third aspect of the present invention, in the phosphor device according to the first aspect or the second aspect, the phosphor layer 120 and the reflective layer 130 are in contact with each other.

[0120] This can improve the adhesion between the reflective layer 130 and the phosphor layer 120, and suppress the peeling of the reflective layer 130. Therefore, the reliability of the phosphor device according to the present embodiment can be improved.

[0121] In addition, for example, in the phosphor device related to the fourth technical solution of the present invention, in the phosphor device related to any one of the first to third technical solutions, the thickness t1 of the phosphor layer 120 is greater than 20 μm and less than 150 μm, and the thickness t2 of the reflective layer 130 is greater than 1.0% of the thickness t1 of the phosphor layer 120.

[0122] This can improve the mechanical strength of the reflective layer 130 and suppress the peeling of the layer.

[0123] Furthermore, for example, in the phosphor device according to the fifth aspect of the present invention, in the phosphor device according to any one of the first to fourth aspects, the ratio of the plurality of pores 121 in the phosphor layer 120 is 1% to 9%.

[0124] This makes it possible to achieve both improvement in the light incident efficiency to the optical system (not shown) and suppression of a decrease in light emission efficiency.

[0125] Furthermore, for example, in the phosphor device according to a sixth aspect of the present invention, in the phosphor device according to any one of the first to fifth aspects, the first metal is Ag.

[0126] This makes it possible to achieve high adhesion and high thermal conductivity, thereby improving the reliability and heat dissipation of the phosphor device.

[0127] In addition, for example, the phosphor device related to the 7th technical solution of the present invention is provided with a reflective layer 230 in the phosphor device related to any one of the 1st to 6th technical solutions, wherein the reflective layer 230 is arranged between the reflective layer 130 and the bonding layer 140 and has a reflective characteristic different from that of the reflective layer 130.

[0128] Thus, light having a large incident angle can be reflected by the reflective layer 230 , so that a stable high reflectivity can be achieved even when the incident angle is large.

[0129] Furthermore, for example, in the phosphor device according to an eighth aspect of the present invention, in the phosphor device according to the seventh aspect, the reflective layer 230 contains metal as a main component.

[0130] Thus, light having a large incident angle can be reflected by the reflective layer 230 , so that a stable high reflectivity can be achieved even when the incident angle is large.

[0131] Furthermore, for example, the phosphor device according to the ninth aspect of the present invention includes the planarization layer 133 disposed between the phosphor layer 120 and the reflective layer 230 in the phosphor device according to the seventh aspect or the eighth aspect.

[0132] Thus, the surface irregularities of the phosphor layer 120 can be alleviated, and the film quality of the multilayer structure of the reflective layer 130 can be improved. In addition, since the stress from the planarization layer 133 can be alleviated by the multilayer structure of the reflective layer 130, the adhesion of the phosphor layer 120 can be improved and the occurrence of warping can be suppressed.

[0133] Furthermore, for example, in the phosphor device according to the tenth aspect of the present invention, in the phosphor device according to the ninth aspect, the planarization layer 133 is the layer closest to the phosphor layer 120 in the multilayer structure of the reflective layer 130 .

[0134] This makes it possible to achieve both relaxation of the incident angle dependency of the reflectance and stress relaxation.

[0135] Furthermore, for example, in the phosphor device according to the eleventh aspect of the present invention, in the phosphor device according to any one of the seventh to tenth aspects, the thickness of the reflective layer 130 is not less than 1.0% and less than 10% of the thickness of the phosphor layer 120 .

[0136] This can improve the mechanical strength of the reflective layer 130 and suppress layer peeling, etc. In addition, by not making the reflective layer 130 too thick, stress can be suppressed and peeling or warping of the phosphor layer 120 can be reduced.

[0137] Furthermore, for example, in the phosphor device according to the twelfth aspect of the present invention, in the phosphor device according to any one of the seventh to eleventh aspects, the reflective layer 230 is provided between the reflective layer 130 and the metal layer 150 .

[0138] Thus, light having a large incident angle can be reflected by the reflective layer 230 , so that a stable high reflectivity can be achieved even when the incident angle is large.

[0139] (other)

[0140] As mentioned above, the phosphor device according to the present invention has been described based on the above-mentioned embodiment, but the present invention is not limited to the above-mentioned embodiment.

[0141] For example, the phosphor layer 120 and the reflective layer 130 may not be in contact with each other. For example, a planarization film (a layer different from the low refractive index layer 132 ) may be provided between the phosphor layer 120 and the reflective layer 130 .

[0142] In addition, for example, the present invention can be implemented as a method for manufacturing the above-mentioned phosphor device, or can be implemented as a light-emitting device having the above-mentioned phosphor device. The light-emitting device is, for example, a light source device or an illumination device of an image projection device or a display device.

[0143] In addition, various modifications that can be conceived by those skilled in the art to the embodiments and embodiments achieved by arbitrarily combining the components and functions of the embodiments without departing from the gist of the present invention are also included in the present invention.

[0144] Description of symbols

[0145] 100, 200 phosphor equipment

[0146] 110 substrate

[0147] 120 Phosphor layer

[0148] 121 pores

[0149] 130 reflection layer (first reflection layer)

[0150] 131 High refractive index layer

[0151] 132 Low refractive index layer

[0152] 133 Planarization layer

[0153] 140 Bonding layer

[0154] 150 Metal Layers

[0155] 160 protective layer

[0156] 230 reflection layer (second reflection layer)

Claims

1. A phosphor device, wherein: have: substrate; a phosphor layer comprising a plurality of pores; A first reflective layer is provided between the substrate and the phosphor layer; a bonding layer disposed between the substrate and the first reflective layer and comprising a first metal; and a metal layer disposed between the first reflective layer and the bonding layer and containing a second metal having a higher melting point than the first metal, The first reflective layer has a multilayer structure in which high refractive index layers and low refractive index layers having a refractive index lower than that of the high refractive index layers are alternately stacked.

2. The phosphor device of claim 1, wherein: The phosphor layer is ceramic.

3. The phosphor device of claim 1, wherein: The phosphor layer and the first reflecting layer are in contact with each other.

4. The phosphor device according to any one of claims 1 to 3, wherein: The thickness of the phosphor layer is greater than or equal to 20 μm and less than or equal to 150 μm; The thickness of the first reflective layer is 1.0% or more of the thickness of the phosphor layer.

5. The phosphor device according to any one of claims 1 to 3, wherein: A ratio of the plurality of pores in the phosphor layer is greater than or equal to 1% and less than or equal to 9%.

6. The phosphor device according to any one of claims 1 to 3, wherein: The first metal is Ag.

7. The phosphor device according to any one of claims 1 to 3, wherein: A second reflective layer is provided between the first reflective layer and the bonding layer and has a reflective property different from that of the first reflective layer.

8. The phosphor device of claim 7, wherein: The second reflective layer contains metal as a main component.

9. The phosphor device of claim 7, wherein: A planarizing layer is provided between the phosphor layer and the second reflecting layer.

10. The phosphor device of claim 9, wherein: The planarizing layer is a layer closest to the phosphor layer in the multilayer structure of the first reflecting layer.

11. The phosphor device of claim 7, wherein: The thickness of the first reflective layer is not less than 1.0% and less than 10% of the thickness of the phosphor layer.

12. The phosphor device of claim 7, wherein: The second reflective layer is provided between the first reflective layer and the metal layer.

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