TWI882963B - Phosphor plate and light emitting device using the same - Google Patents

Abstract

A phosphor plate formed from a complex containing an α-SiAlON phosphor and a sintered compact that contains alumina.

Description

Fluorescent panel and light-emitting device using the same

The present invention relates to a fluorescent panel and a lighting device using the fluorescent panel.

Various developments have been made in the field of fluorescent plates. For example, the technology described in Patent Document 1 is known. Patent Document 1 describes a plate-shaped luminescent color conversion component in which an inorganic fluorescent material is dispersed in _SiO2 -based glass (Figure 4 of Patent Document 1, claim 1). [Prior Technical Document] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2010-132923

[The problem that the invention wants to solve]

However, after research by the inventors of this case, it was found that the plate-shaped luminous color conversion component described in Patent Document 1 still has room for improvement in terms of luminous efficiency. [Means for solving the problem]

The inventors of the present invention conducted further research and found that by combining and compounding α-type silicon aluminum oxynitride phosphor and aluminum oxide (Al ₂ O ₃ ) with appropriate materials, a phosphor plate with stable luminous efficiency can be realized, thereby completing the present invention.

According to the present invention, a fluorescent plate is provided, which is composed of a composite body, wherein the composite body comprises: an α-type silicon aluminum oxynitride fluorescent body, and a sintered body containing aluminum oxide.

According to the present invention, a light-emitting device is provided, comprising: a group III nitride semiconductor light-emitting element; and a phosphor plate disposed on one surface of the group III nitride semiconductor light-emitting element. [Effect of the invention]

According to the present invention, a fluorescent panel with excellent luminous efficiency and a light-emitting device using the fluorescent panel are provided.

The following drawings are used to illustrate the embodiments of the present invention. In addition, in all drawings, the same elements are marked with the same symbols, and the description is appropriately omitted. In addition, the drawings are only schematic drawings and are not consistent with the actual size ratio.

The outline of the fluorescent plate of this embodiment is described. The fluorescent plate of this embodiment is composed of a plate-shaped element formed by a composite body, and the composite body includes: an α-type silicon aluminum oxynitride fluorescent body and a sintered body containing aluminum oxide.

The fluorescent plate has the function of a wavelength converter that converts the irradiated blue light into orange light and emits light.

According to the experience of the inventors of this case, it is found that by combining appropriate materials of α-type silicon aluminum oxynitride phosphor and aluminum oxide (Al ₂ O ₃ ) as components constituting a composite, a phosphor panel with stable luminous efficiency can be realized.

Although the detailed mechanism has not been determined, it is believed that because the refractive index difference between the α-type silicon aluminum oxynitride phosphor and alumina is moderately reduced, it is easier to obtain light emitted from the α-type silicon aluminum oxynitride phosphor than a composite of the α-type silicon aluminum oxynitride phosphor and glass powder (SiO ₂ ), and the light conversion efficiency is improved. In addition, the use of alumina can improve the thermal conductivity compared to the case of using glass powder. As a result, the decrease in luminous intensity due to heating is suppressed, so the phosphor plate of this embodiment can be applied to high-power light-emitting elements.

On the other hand, if the difference in refractive index is too small, such as the combination of YAG phosphor and alumina, light scattering is difficult to occur, and the content of the phosphor needs to be increased to prevent the transmission of blue light. In contrast, it is believed that the refractive index difference between α-type silicon aluminum oxynitride phosphor and alumina is moderately large, which promotes the scattering of blue light, and can effectively suppress the transmission of blue light when the phosphor content is low, and can emit high-brightness orange light.

Here, the known representative values of the refractive index of each component are: α-SiANO3 phosphor: about 2, YAG _phosphor : about 1.8, _Al2O3 : about 1.7, _SiO2 : about 1.4.

According to the fluorescent plate, when irradiated with blue light of wavelength 455nm, the peak wavelength of wavelength conversion light emitted from the fluorescent plate is preferably above 585nm and below 605nm. In addition, according to this point, by combining a light-emitting element emitting blue light with a fluorescent plate, a light-emitting device emitting high-brightness orange light can be obtained.

The structure of the fluorescent panel of this embodiment will be described in detail.

In the composite constituting the phosphor plate, α-type silicon aluminum oxynitride phosphor and aluminum oxide are mixed. The so-called mixing refers to the state in which the α-type silicon aluminum oxynitride phosphor is dispersed in the aluminum oxide as the base material (matrix phase). That is, the composite can have a structure in which the α-type silicon aluminum oxynitride phosphor particles are dispersed between and/or within the grains of the (polycrystalline) crystals constituted by the base material. The α-type silicon aluminum oxynitride phosphor particles can be uniformly dispersed in the base material (alumina sintered body).

(α-type silicon aluminum oxynitride phosphor) The α-type silicon aluminum oxynitride phosphor of this embodiment comprises an α-type silicon aluminum oxynitride phosphor containing Eu element represented by the following general formula (1). (M) _{m (1- x )/ p} (Eu) _{mx /2} (Si) _{12-( m + n )} (Al) _{m + n} (O) _n (N) _{16- n} ･･General formula (1)

In the general formula (1), M represents one or more elements selected from the group consisting of Li, Mg, Ca, Y and iodine elements, excluding La and Ce; p is the valence of the M element; 0>x>0.5; 1.5≦m≦4.0; 0≦n≦2.0. For example, n can be less than 2.0, less than 1.0, or less than 0.8.

The solid solution composition of α-type silicon aluminum oxynitride is as shown in the general formula, in the unit lattice (Si ₁₂ N ₁₆ ) of α-type silicon nitride, m Si-N bonds are replaced by Al-N bonds, n Si-N bonds are replaced by Al-O bonds, and in order to maintain electrical neutrality, m/p cations (M, Eu) are interstitially dissolved in the lattice. In particular, when Ca is used as M, α-type silicon aluminum oxynitride can be stable in a wide composition range, and by replacing a part of it with Eu as the luminescent center, a phosphor that can be excited in a wide wavelength range from ultraviolet light to blue light and emits visible light from yellow to orange can be obtained.

Generally, since α-type silicon aluminum oxynitride has a second crystalline phase different from the α-type silicon aluminum oxynitride and an amorphous phase inevitably exists, the solid solution composition cannot be strictly defined by component analysis, etc. The crystal phase of α-type silicon aluminum oxynitride is preferably a single phase of α-type silicon aluminum oxynitride, and may also contain β-type silicon aluminum oxynitride, aluminum nitride or its polytypoid, Ca ₂ Si ₅ N ₈ , CaAlSiN ₃ , etc. as other crystal phases.

As for the manufacturing method of α-silicon aluminum oxynitride phosphor, there is a method of heating a mixed powder composed of silicon nitride, aluminum nitride and a compound of an interstitial solid solution element in a high-temperature nitrogen environment and reacting it. A part of the components forms a liquid phase in the heating step, and the substance moves in this liquid phase, thereby generating an α-silicon aluminum oxynitride solid solution. After the synthesis, multiple equiaxed primary particles of the synthesized α-silicon aluminum oxynitride phosphor are sintered to form block-shaped secondary particles. The primary particles in this embodiment refer to the smallest particles that have the same crystal orientation within the particles and can exist independently.

The lower limit of the average particle size of the α-type silicon aluminum oxynitride phosphor is preferably 5 μm or more, more preferably 10 μm or more. Furthermore, the upper limit of the average particle size of the α-type silicon aluminum oxynitride phosphor is preferably 30 μm or less, more preferably 20 μm or less. The average particle size of the α-type silicon aluminum oxynitride phosphor is the size of the secondary particles. If the average particle size of the α-type silicon aluminum oxynitride phosphor is 5 μm or more, the transparency of the composite can be further improved. On the other hand, if the average particle size of the α-type silicon aluminum oxynitride phosphor is 30 μm or less, the occurrence of fragmentation can be suppressed when the phosphor plate is cut by a cutting machine or the like.

Here, the average particle size of the α-silicon aluminum oxynitride phosphor refers to the particle size D50 when the cumulative passing matter (cumulative passing matter ratio) from the small particle size side is 50% in the volume-based particle size distribution measured by a laser diffraction scattering type particle size distribution measurement method (manufactured by Beckman Coulter Co., Ltd., LS13-320).

The lower limit of the content of the α-type silicon aluminum oxynitride phosphor is, for example, 5 Vol% or more, preferably 10 Vol% or more, and more preferably 15 Vol% or more, calculated by volume relative to the entire composite. This can increase the luminous intensity of the thin-layer phosphor plate. It can also improve the light conversion efficiency of the phosphor plate. On the other hand, the upper limit of the content of the α-type silicon aluminum oxynitride phosphor is, for example, 50 Vol% or less, preferably 45 Vol% or less, and more preferably 40 Vol% or less, calculated by volume relative to the entire composite. This can suppress the reduction of the thermal conductivity of the phosphor plate.

The alumina in the sintered body can increase the luminous intensity of the fluorescent plate because it absorbs less visible light. And because the thermal conductivity of alumina is high, the heat resistance of the fluorescent plate containing alumina can be improved. In addition, because alumina has excellent mechanical strength, the durability of the fluorescent plate can be improved.

The aluminum oxide in the sintered body preferably has fewer impurities from the viewpoint of light extraction efficiency. For example, the purity of the Al ₂ O ₃ compound in the aluminum oxide in the sintered body may be, for example, 98%wt or more, preferably 99%wt or more.

The alumina in the sintered body may include at least one selected from the group consisting of α-alumina and γ-alumina. This can improve the light conversion efficiency of the fluorescent plate.

The lower limit of the content of α-silicon aluminum oxynitride phosphor and aluminum oxide is, for example, 95 Vol% or more, preferably 98 Vol% or more, and more preferably 99 Vol% or more, based on the volume of the entire composite. That is, the composite constituting the phosphor plate includes α-silicon aluminum oxynitride phosphor and aluminum oxide as main components. In this way, in addition to improving heat resistance and durability, stable luminous efficiency can also be achieved. On the other hand, the upper limit of the content of α-silicon aluminum oxynitride phosphor and aluminum oxide is not particularly limited, for example, it can be 100 Vol% or less based on the volume of the entire composite.

The lower limit of the thermal conductivity of the fluorescent plate is, for example, 10 W/m•k or more, preferably 15 W/m•k, and more preferably 20 W/m•k or more. This can achieve a high thermal conductivity, thereby achieving a fluorescent plate with excellent heat resistance. On the other hand, the upper limit of the thermal conductivity of the fluorescent plate is not particularly limited, and can be, for example, 40 W/m•k or less.

In recent years, it is known that the temperature of the fluorescent body tends to rise due to the high brightness of the light source. Even in this case, by using a fluorescent plate with excellent thermal conductivity, it is still possible to emit high-brightness orange light stably.

At least the main surface of the fluorescent plate, or both the main surface and the back surface, may be subjected to surface treatment. Examples of surface treatment include grinding, fine grinding, polishing, and the like using a diamond wheel or the like. The surface roughness Ra of the main surface of the fluorescent plate is, for example, 0.1 μm to 2.0 μm, preferably 0.3 μm to 1.5 μm. On the other hand, the surface roughness Ra of the back surface of the fluorescent plate is, for example, 0.1 μm to 2.0 μm, preferably 0.3 μm to 1.5 μm. By making the surface roughness not higher than the upper limit, the light extraction efficiency and the deviation of the light intensity in the in-plane direction can be suppressed. By making the surface roughness higher than the lower limit, it is expected that the adhesion to the adherend will be improved.

In the fluorescent plate, the upper limit of the light transmittance of blue light at 450nm is, for example, less than 10%, preferably less than 5%, and more preferably less than 1%. Accordingly, since the blue light can be suppressed from passing through the fluorescent plate, a higher brightness orange light can be emitted. By appropriately adjusting the content of the α-type silicon aluminum oxynitride phosphor and the thickness of the fluorescent plate, the light transmittance of blue light at 450nm can be reduced. In addition, the lower limit of the light transmittance of blue light at 450nm is not particularly limited, for example, it can be more than 0.01%.

The manufacturing steps of the fluorescent plate of this embodiment are described in detail.

The manufacturing method of the fluorescent plate of the present embodiment may include: a step (1) of mixing aluminum oxide powder with α-type silicon aluminum oxynitride fluorescent powder containing at least EU element as the luminescent center, and a step (2) of heating and calcining the mixture of aluminum oxide powder and α-type silicon aluminum oxynitride fluorescent powder at a temperature of not less than 1300° C. and not more than 1700° C. to form a dense composite.

In step (1), the aluminum oxide powder and α-silicon aluminum oxynitride phosphor powder used as raw materials should be as pure as possible, and the impurity elements other than the constituent elements should be less than 0.1%. In addition, the phosphor plate of the present invention is densified by sintering the aluminum oxide powder, so it is preferable to use fine powder aluminum oxide, and the average particle size of the aluminum oxide powder used as the raw material should be less than 1 μm. The raw material powders can be mixed by various methods such as dry and wet methods, but the method of preventing the α-silicon aluminum oxynitride phosphor particles used as the raw material from being crushed as much as possible and preventing the impurities from the device from being mixed as much as possible during mixing is more ideal.

In step (2), the mixture of aluminum oxide powder and α-silicon aluminum oxynitride phosphor powder is calcined at a temperature of 1300°C to 1700°C. In order to densify the composite, the calcination temperature should be high, but the higher the calcination temperature, the lower the fluorescence characteristics of the α-silicon aluminum oxynitride phosphor will be, so the above range is ideal. The calcination method can be normal pressure sintering or pressure sintering, but in order to suppress the degradation of the characteristics of the α-silicon aluminum oxynitride phosphor and to obtain a dense composite, pressure sintering is more preferred than normal pressure sintering because it is easier to achieve densification. Pressurized sintering methods, such as hot pressing sintering, discharge plasma sintering (SPS), hot isostatic sintering (HIP), etc. If hot pressing sintering or SPS sintering is used, the pressure should be above 10MPa, preferably above 30MPa, and preferably below 100MPa. In order to prevent the oxidation of α-silicon aluminum nitride oxides, the calcining environment should be non-oxidizing blunt gases such as nitrogen and argon, or a vacuum environment.

The light-emitting device of this embodiment is described.

The light-emitting device of this embodiment has a group III nitride semiconductor light-emitting element (light-emitting element 20) and the phosphor plate 10 disposed on one surface of the group III nitride semiconductor light-emitting element. The group III nitride semiconductor light-emitting element is composed of a group III nitride semiconductor such as aluminum gallium nitride, gallium nitride, aluminum indium gallium nitride and has an n-layer, a light-emitting layer, and a p-layer. A blue LED emitting blue light can be used as the group III nitride semiconductor light-emitting element. The phosphor plate 10 can be directly disposed on one surface of the light-emitting element 20, or it can be disposed through a light-transmitting member or a spacer.

The fluorescent plate 10 disposed on the light-emitting element 20 may be a circular plate-shaped fluorescent plate 100 (fluorescent wafer) as shown in FIG. 1 , or may be obtained by dividing the fluorescent plate 100 . FIG. 1 is a schematic diagram showing an example of the arrangement of the fluorescent plate. The thickness of the fluorescent plate 100 shown in FIG. 1 may be, for example, 100 μm or more and 1 mm or less. After the fluorescent plate 100 is obtained in the above steps, the thickness of the fluorescent plate 100 may be appropriately adjusted by grinding or the like. In addition, the circular plate-shaped fluorescent plate 100 can suppress the occurrence of defects and cracks at the corners compared to the rectangular shape, so it has better durability and transportability.

Examples of the semiconductor device are shown in Fig. 2 (a) and (b). Fig. 2 (a) is a cross-sectional view schematically showing the configuration of a flip chip type light emitting device 110, and Fig. 2 (b) is a cross-sectional view schematically showing the configuration of a wire bonding type light emitting device 120.

The light-emitting device 110 of FIG. 2(a) comprises a substrate 30, a light-emitting element 20 electrically connected to the substrate 30 via a solder 40 (crystal bonding material), and a fluorescent plate 10 disposed on the light-emitting surface of the light-emitting element 20. The flip-chip type light-emitting device 110 may be a face-up type or a face-down type. In addition, the light-emitting device 120 of FIG. 2(b) comprises a substrate 30, a light-emitting element 20 electrically connected to the substrate 30 via a bonding wire 60 and an electrode 50, and a fluorescent plate 10 disposed on the light-emitting surface of the light-emitting element 20. In FIG. 2 , the light-emitting element 20 and the fluorescent plate 10 are bonded by a known method, for example, by a polysilicone adhesive and thermal fusion. In addition, the entire light emitting device 110 and the entire light emitting device 120 may be sealed with a transparent sealing material.

In addition, the divided fluorescent plate 10 may be bonded to the light emitting element 20 mounted on the substrate 30. It is also possible to bond a plurality of light emitting elements 20 to a large area fluorescent plate 100, and then separate each light emitting element 20 attached to the fluorescent plate 10 by cutting. In addition, it is also possible to bond a large area fluorescent plate 100 to a semiconductor wafer having a plurality of light emitting elements 20 formed on the surface, and then separate the semiconductor wafer and the fluorescent plate 100 together.

The above describes the implementation of the present invention. These are examples of the present invention, but various configurations other than the above can also be adopted. [Implementation]

Hereinafter, the present invention will be described in detail with reference to the embodiments, but the present invention should not be limited to the description of these embodiments.

(Example 1) Alumina powder (TM-DAR, manufactured by Da Ming Chemical Industry Co., Ltd.) and Ca-α silicon aluminum oxynitride phosphor (ALON BRIGHT YL-600B, manufactured by Denki Chemical Industry Co., Ltd., average particle size D50: 15 μm) were used as raw materials for the phosphor plate of Example 1. 7.857 g of alumina powder and 2.833 g of Ca-α silicon aluminum oxynitride phosphor powder were weighed and dry mixed with an agate mortar. The mixed raw materials were passed through a nylon mesh screen with a mesh size of 75 μm and agglomerated and dispersed to obtain a mixed powder of the raw materials. In addition, the mixing ratio calculated from the true density of the raw materials (alumina: 3.97 g/cm ³ , Ca-α-silicon aluminum oxynitride phosphor: 3.34 g/cm ³ ) is alumina:Ca-α-silicon aluminum oxynitride phosphor = 70:30 volume %.

About 11 g of the raw material mixed powder was filled into a carbon mold with an inner diameter of 30 mm and a carbon upper punch was set to sandwich the raw material powder. In addition, a 0.127 mm thick carbon sheet (GRAFOIL, manufactured by GraTech) was placed between the raw material mixed powder and the carbon jig to prevent sticking.

The hot-pressing jig filled with the raw material mixed powder is placed in a multi-purpose high-temperature furnace (Hi multi 5000, manufactured by Fuji Electric Industries, Ltd.) with a carbon heater. The furnace is evacuated to a pressure of less than 0.1 Pa, and the depressurized state is maintained, and the upper and lower punches are pressurized at a pressure of 55 MPa. The pressurized state is maintained, and the temperature is raised to 1600°C at a rate of 5°C per minute. After reaching 1600°C, the heating is stopped, and the mixture is slowly cooled to room temperature and the pressure is reduced. After that, the calcined product with an outer diameter of 30 mm is recovered, and the outer periphery is ground with a flat grinding disk and a cylindrical grinding disk to obtain a disk-shaped fluorescent plate with a diameter of 25 mm and a thickness of 1.5 mm. The bulk density of the phosphor plate of Example 1 was measured by a method based on JIS-R1634:1998 and was 3.729 g/cm ³ . The theoretical density of the mixture calculated from the true density of the raw materials and the mixing ratio was 3.781 g/cm ³ , so the relative density of the phosphor plate of Example 1 was 98.6%. The phosphor plate of Example 1 was ground and observed by SEM, and it was observed that Ca-α silicon aluminum oxynitride phosphor particles were dispersed between the aluminum oxide matrix phases. The surface roughness Ra of the main surface of the fluorescent plate of Example 1 measured using a surface roughness tester (SJ-400 manufactured by Mitutoyo) in accordance with JIS B0601:1994 was 1.0 μm, and the surface roughness Ra of the back surface opposite to the main surface was also 1.0 μm.

(Example 2) The same aluminum oxide powder and Ca-α silicon aluminum oxynitride phosphor as in Example 1 were used as raw materials for the phosphor plate of Example 2. 6.701 g of aluminum oxide powder and 3.777 g of Ca-α silicon aluminum oxynitride phosphor were weighed and dry mixed using an agate mortar. The mixing ratio calculated from the true density of the raw materials was aluminum oxide: Ca-α silicon aluminum oxynitride phosphor = 60:40 volume %. The method for making the phosphor plate of Example 2 was the same as the method for making the phosphor plate of Example 1 except that the mixing ratio of aluminum oxide powder and Ca-α silicon aluminum oxynitride phosphor was different. The bulk density of the fluorescent plate of Example 2 was measured by the same method as that of Example 1, and the result was 3.665 g/cm ³ . The theoretical density of the raw material mixture is 3.717 g/cm ³ , so the relative density of the fluorescent plate of Example 2 is 98.6%. The surface roughness Ra of the main surface of the fluorescent plate of Example 2 is 1.0 μm, and the surface roughness Ra of the back surface opposite to the main surface is 1.1 μm.

(Comparative Example 1) _SiO2 powder (FB-9DC grade, manufactured by Denki Kagaku Kogyo Co., Ltd.) and Ca-α silicon aluminum oxynitride phosphor (ALON BRIGHT YL-600B, manufactured by Denki Kagaku Kogyo Co., Ltd.) were used as raw materials for the phosphor plate of Comparative Example 1. 4.354 g _{of SiO2} powder and 2.723 g of Ca-α silicon aluminum oxynitride phosphor were weighed and dry mixed using an agate mortar. The mixed raw materials were passed through a nylon mesh screen with a mesh size of 75 μm to obtain a mixed powder of the raw materials. The mixing ratio calculated from the true density of the raw materials was _SiO2 :Ca-α silicon aluminum oxynitride phosphor = 70:30 volume %. About 7 g of the raw material mixed powder was filled into the same hot pressing carbon mold as in Example 1, and hot pressing sintering was performed in a multi-purpose high temperature furnace. The furnace was evacuated to below 0.1 Pa, and the depressurized state was maintained. The temperature was raised from room temperature at a rate of 20°C per minute. Nitrogen was introduced into the furnace at 800°C to make the gas pressure in the furnace 0.1 MPa･G. After the nitrogen was introduced, the temperature was raised to 1375°C at a rate of 5°C per minute and maintained at 1375°C for 15 minutes. Thereafter, the temperature was lowered to room temperature at a rate of 5°C per minute, and after the pressure was reduced, the calcined product with an outer diameter of 30 mm was recovered and processed in the same manner as in Example 1 to obtain a disk-shaped fluorescent plate with a diameter of 25 mm and a thickness of 1.5 mm.

[Thermal conductivity measurement] The thermal conductivity of the fluorescent plates of Examples 1 and 2 and Comparative Example 1 at room temperature (25°C) was measured by the flash method in accordance with JIS1611:2010. ･Heat diffusion rate: measured by a xenon flash analyzer (LFA447, manufactured by NETZSCH Japan Co., Ltd.). ･Specific heat capacity: obtained by a DSC measuring device (DSC8000, manufactured by PerkinElmer) in accordance with JIS K7123. ･Bulk density: measured by a method based on JIS-R1634:1998. Thermal conductivity (W/m･K) = bulk density (g/cm ³ ) × heat diffusion rate (m ² /s) × specific heat capacity (J/(kg･K)) The thermal conductivity of the fluorescent plate of Example 1 is 18W/m･K, the thermal conductivity of the fluorescent plate of Example 2 is 15W/m･K, and the thermal conductivity of the fluorescent plate of Comparative Example 1 is 1.9W/m･K.

[Analysis of crystal structure] The fluorescent plates of Examples 1 and 2 were crushed into powder using a mortar and the diffraction patterns of the obtained samples were measured using an X-ray diffraction device (product name: Ultima IV, manufactured by Rigaku Corporation). The results confirmed the presence of a crystal phase in the alumina sintered body. This crystal phase contains α-alumina as the main phase and a trace amount of γ-alumina mixed therein.

[Evaluation of optical properties] The optical properties of the fluorescent plate are measured using a chip-on-board (COB) LED package 130. FIG3 is a schematic diagram of a device (LED package 130) for measuring the luminous spectrum of the fluorescent plate 100. First, the thickness of the obtained 1.5 mm thick circular plate-shaped fluorescent plate 100 is thinned to 0.25 mm. Next, an aluminum substrate (substrate 30) having a recess 70 is prepared. The bottom surface of the recess 70 has a diameter φ of 13.5 mm, and the opening portion of the recess 70 has a diameter φ of 16 mm. A blue LED (light-emitting element 20) serving as a blue light source is installed inside the recess 70 of the substrate 30. Thereafter, a circular fluorescent plate 100 is disposed on the upper portion of the blue LED to seal the opening of the recess 70 of the substrate 30, thereby manufacturing the device (a chip-on-board (COB) LED package 130) shown in FIG. 3 .

The surface emission spectrum of the fluorescent plate 100 was measured using a full luminous flux measurement system (HalfMoon/φ1000mm integrating sphere system, manufactured by Otsuka Electronics Co., Ltd.) when the blue LED of the manufactured LED package 130 was turned on. The measurement results are shown in FIG4 .

FIG4 shows the luminescence spectrum when the fluorescent plates of Examples 1 and 2 and Comparative Example 1 are used. The luminescence intensity on the vertical axis of FIG4 is a relative value when the maximum luminescence intensity of Example 1 is taken as 100. In addition, in the luminescence spectrum, when the maximum luminescence intensity of orange light (Orange) with a wavelength of 595 nm to 605 nm is taken as _TO , and the maximum luminescence intensity of blue light (Blue) with a wavelength of 445 nm to 465 nm is taken as _TB , the transmission amount of blue light from the blue LED is defined as _TB / _TO .

As shown in FIG. 4 , the peak wavelength of the luminescence spectrum of Examples 1, 2 and Comparative Example 1 is about 600 nm. However, it can be seen that the luminescence intensity at the peak wavelength in Examples 1 and 2 is higher than that in Comparative Example 1. In addition, in any of Examples 1, 2 and Comparative Example 1, the spectrum of the transmitted light from the blue LED can be slightly observed around the wavelength of 450 nm. However, it can be seen that the transmittance _TB / _TO of the blue light from the blue LED in Examples 1 and 2 is the same as that in Comparative Example 1. In addition, in the fluorescent plate of Example 1, the light transmittance of the blue light at a wavelength of 450 nm is 1.5%, which can be understood that the transmission of the blue light is sufficiently suppressed. It can be understood that by using the fluorescent panels of Examples 1 and 2, a light-emitting device having excellent fluorescent intensity of orange light and excellent luminous efficiency of converting blue light into orange light can be realized.

This application is based upon and claims priority from Japanese application No. 2018-189141 filed on October 4, 2018, the entire contents of which are incorporated herein in their entirety.

10: Fluorescent plate 20: Light-emitting element 30: Substrate 40: Solder 50: Electrode 60: Bonding wire 70: Recess 100: Fluorescent plate 110: Light-emitting device 120: Light-emitting device 130: Package

The above-mentioned objects, as well as other objects, features and advantages will be further clarified through the preferred implementation modes described below and the accompanying drawings.

[Figure 1] is a schematic diagram showing an example of the structure of the fluorescent plate of the present embodiment. [Figure 2] (a) is a cross-sectional diagram schematically showing the structure of a flip-chip type light-emitting device, and (b) is a cross-sectional diagram schematically showing the structure of a wire-bonding type light-emitting element. [Figure 3] is a schematic diagram of a device for measuring the luminescence spectrum of a composite. [Figure 4] is a luminescence spectrum obtained from the composites of Examples 1 and 2 and Comparative Example 1.

100: Fluorescent board

Claims (8)

A fluorescent plate is composed of a composite, wherein the composite comprises: an α-type silicon aluminum oxynitride phosphor and a sintered body containing aluminum oxide; the α-type silicon aluminum oxynitride phosphor comprises an α-type silicon aluminum oxynitride phosphor containing the Eu element represented by the following general formula (1); the content of the α-type silicon aluminum oxynitride phosphor is 5 vol% or more and 50 vol% or less, calculated by volume, relative to the entire composite; the total content of the α-type silicon aluminum oxynitride phosphor and the aluminum oxide is 95 vol% or more and 100 vol% or less, calculated by volume, relative to the entire composite; The thermal conductivity of the fluorescent plate is not less than 10 W/m･K and not more than 40 W/m･K; (M) _m(1-x)/p (Eu) _mx/2 (Si) _12-(m+n) (Al) _m+n (O) _n (N) _16-n ･･General formula (1) In the general formula (1), M represents one or more elements selected from the group consisting of Li, Mg, Ca, Y and yttrium elements, but excluding La and Ce; p is the valence of the M element; 0＜x＜0.5; 1.5≦m≦4.0; 0≦n≦2.0. A fluorescent plate as claimed in claim 1, wherein the aluminum oxide comprises one or more selected from the group consisting of α-aluminum oxide and γ-aluminum oxide. The fluorescent plate of claim 1, wherein the average particle size D50 of the α-silicon aluminum oxynitride fluorescent material in the composite is greater than 5 μm and less than 30 μm. A fluorescent plate as claimed in claim 1, wherein the surface roughness Ra of the main surface of the fluorescent plate is greater than 0.1 μm and less than 2.0 μm. The fluorescent plate of claim 1 is used as a wavelength converter that converts the irradiated blue light into orange light and emits light. A fluorescent plate as claimed in any one of claims 1 to 5, wherein the light transmittance of 450nm blue light is less than 10%. A light-emitting device comprising: A III-nitride semiconductor light-emitting element; and A fluorescent plate as claimed in any one of claims 1 to 6 disposed on one surface of the III-nitride semiconductor light-emitting element. A method for manufacturing a fluorescent plate is a method for manufacturing a fluorescent plate as in any one of claims 1 to 6, wherein the fluorescent plate is composed of a composite comprising an α-type silicon aluminum oxynitride phosphor and a sintered body containing aluminum oxide; It comprises: heating a raw material mixed powder of aluminum oxide powder and α-type silicon aluminum oxynitride phosphor powder at a temperature of not less than 1300°C and not more than 1700°C, and obtaining a calcination step of the composite.

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