JP5246774B2 - Phosphor member, light emitting element, and lighting device - Google Patents

Description

  The present invention relates to a phosphor member, a light emitting element using the phosphor member, and an illumination device.

  Light emitting diodes (LEDs) that emit blue / ultraviolet light with a wavelength of around 400 nm have a long lifetime, and light emitting elements using the light emitting diodes are excited by light emitted from the LEDs and have different wavelengths, such as green yellow, red orange By providing a phosphor that emits wavelength-converted light, it is used for illumination light sources and various displays as a mixture of blue and ultraviolet light to emit white light.

  However, sulfide phosphors that emit near-ultraviolet / blue as excitation sources and high-intensity fluorescence from green to red as phosphors for light-emitting elements are green-yellow fluorescent using emission from blue / ultraviolet light-emitting diodes as excitation sources. As a wavelength converter, it emits fluorescent light having an intensity equal to or higher than that of a YAG fluorescent material that is widely used as a fluorescent material that emits light. However, sulfide phosphors are susceptible to environmental degradation such as moisture and oxygen, have a short life when used in a light-emitting element, and hinder the extension of the life of LED elements. In order to suppress environmental degradation of the phosphor, a light emitting diode (Patent Document 1) using phosphor particles coated with a moisture-resistant material such as glass, or a glass coating to suppress a decrease in luminance due to light emission from the LED. The phosphor-containing glass powder (Patent Document 2), the phosphor-containing glass sheet (Patent Document 3) including a phosphor having an oxide coating has been reported in order to suppress deterioration in the environment and manufacturing process. Yes.

In addition, in a light-emitting device using a phosphor having a coating of a resin material in order to increase the heat resistance of a nitride phosphor or the like, the dispersibility of the phosphor having a coating in the resin or the like is reduced during the production, and the fluorescence Due to secondary aggregation of the body, color unevenness may occur in light emission from the light emitting device. For this reason, a wavelength conversion member (Patent Document 4) has been reported in which a coating having a dielectric constant larger than this is provided on the phosphor particles to suppress a decrease in dispersibility of the phosphor particles formed of oxynitride or nitride. ing.
JP2004-88009A JP 2006-52345 A JP 2008-115223 A JP 2008-150518 A

  An object of the present invention is to suppress degradation due to the environment, and to suppress the occurrence of uneven color in the light emitted from the light emitting element by sufficiently diffusing the fluorescence emitted from the phosphor when used in the light emitting element. An object of the present invention is to provide a phosphor member that can be used. In particular, it is to provide a light emitting element capable of emitting white light with suppressed color unevenness and an illumination device using the light emitting element.

  The present inventors have coated phosphor particles that are excited by light emitted from an LED and emit wavelength-converted light with a plurality of coating layers to suppress degradation of the phosphor due to the environment. As the outer shape of each phosphor member of the phosphor member formed of glass is asymmetric, the wavelength-converted light emitted from the light emitting element using the phosphor member is sufficiently diffused to suppress the occurrence of color unevenness. I got the knowledge that I can do it. Furthermore, the knowledge that phosphor particles covered with a coating layer in one phosphor member contain a combination of a plurality of phosphor particles as appropriate can emit white light with suppressed color unevenness. Obtained. Obtaining such knowledge, the present invention has been completed.

That is, the present invention relates to a phosphor particle that is excited by light emitted from a phosphor and emits wavelength-converted light, an intermediate coating layer that coats the phosphor particle, and a glass layer that includes glass that coats the intermediate coating layer, has a median diameter of 10μm or more, the phosphor maximum diameter at 30μm or less is coated with and the intermediate coating layer as 10 to 100 times the outer shape coated with asymmetric phosphor particles in the intermediate coat layer of median diameter A glass layer is formed by pulverizing a sintered body obtained by forming and sintering a mixture containing glass powder having a mass of 4 to 7 times the mass of particles into a sheet having a thickness of 0.2 mm to 2 mm. In addition, the present invention relates to a phosphor member having an asymmetric outer shape with a maximum major axis of 100 μm to 3 mm.

  The present invention also relates to a light emitting element having a light emitter and the fluorescent member, and an illumination device using the light emitting element.

  The fluorescent member of the present invention suppresses deterioration due to the environment, and when used in a light-emitting element, wavelength-converted light emitted from the phosphor is sufficiently diffused to prevent color unevenness from occurring in light emission from the light-emitting element. can do. The light emitting element and the lighting device of the present invention can emit white light with suppressed color unevenness.

The phosphor member of the present invention includes a phosphor particle that is excited by light emitted from a light emitter and emits wavelength-converted light, an intermediate coating layer that covers the phosphor particle, and a glass that includes the glass that covers the intermediate coating layer. and a layer, median diameter 10μm or more, coated with the maximum diameter is 10 to 100 times that of the outer shape is coated with asymmetric phosphor particles in the intermediate coat layer and the intermediate coating layer of the median diameter 30μm or less A glass layer is obtained by pulverizing a sintered body obtained by forming and sintering a mixture containing glass powder having a mass of 4 to 7 times the mass of the phosphor particles into a sheet having a thickness of 0.2 mm to 2 mm. It is characterized by having an asymmetric outer shape formed with a maximum major axis of 100 μm to 3 mm.

  Examples of the light emitter that emits light capable of exciting the phosphor particles in the phosphor member of the present invention include light emitting diodes, laser diodes, and other solid light emitters such as inorganic electroluminescence. Specifically, gallium nitride compounds such as InGaN that emit light having a wavelength of 440 to 480 nm, and light emitting diodes that emit blue / ultraviolet light such as zinc oxide can be used. As the illuminant, it is preferable to select an illuminant in which excitation light emitted from the illuminant and wavelength-converted light emitted from phosphor particles described later are mixed to form white light.

The phosphor particles used in the phosphor member of the present invention are excited by light emitted from the light emitter and emit wavelength-converted light. Examples of the phosphor used for the phosphor particles include sulfides, nitrides, and oxides. As the sulfide phosphor, specifically, a thiogallate phosphor that is activated with Eu or Ce, contains Sr, and may contain one or more of Ca, Ba, Mg, and Zn, Eu or Activated with Ce, Sr, and any one or two or more of Ca, Ba, Mg, and Zn. Activated with Eu or Ce and activated with Ce and containing Sr, Ca, Ba, Mg Examples thereof include thiosilicate phosphors that may contain one or more of these. The nitride phosphor is activated by Eu, Yb, or Ce, contains Ca, and includes any one or more of Sr, Ba, and Mg, an aluminum silicon nitride phosphor, Eu or Yb, Examples thereof include an oxynitride phosphor that is activated with Ce, contains Sr, and may contain one or more of Ca, Ba, and Mg. The phosphor particles are a combination of a phosphor that emits yellow wavelength-converted light and a phosphor that emits wavelength-converted light from green to red, and so on. Is preferred. Examples of combinations of phosphor materials that emit white light include phosphors that emit green light, such as (Ba, Sr, Ca) ₂ SiO ₄ : Eu, SrGa ₂ S ₄ : Eu, β-sialon, (Ba , Sr, Ca) Si ₂ O ₂ N ₂ : Eu, Ba ₃ Si ₆ O ₉ N ₄ : Eu, CaSc ₂ O ₄ : Ce, Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce emits red light. Examples of phosphors include combinations of (Ba, Sr, Ca) ₂ Si ₅ N ₈ : Eu, (Ca, Sr) AlSiN ₃ : Eu, (Sr, Ca) S: Eu, etc. Can do.

The phosphor particles that contour is asymmetric, i.e., each phosphor particle does not have a uniform predetermined shape. Here, that the outer shape is asymmetric means that the shape is not fixed and the size is not uniform. Specifically, the phosphor particles each have an outer shape such as a polygonal shape, a rod shape, a planar shape, a spherical shape, etc., and the entire phosphor particles have various shapes and are not uniform in size. It is preferable that When the outer shape of the phosphor particles is asymmetric, it is easy to form the outer shape of the phosphor member asymmetrically. The size of the phosphor particles as a main Dian diameter (D50), is 10 to 30 [mu] m, the maximum diameter is 10 to 100 times the median diameter. A value obtained by observation with an electron microscope (SEM) can be adopted as the maximum major axis of the particles.

  The intermediate coating layer covering the surface of the phosphor particles is transparent with high transmittance for light emitted from the phosphor and wavelength-converted light from the phosphor particles, and the phosphor particles are protected from heat and the environment. What can suppress the deterioration which receives is preferable. The intermediate coating layer preferably contains an oxide, and examples of the oxide include silicon oxide, yttrium oxide, aluminum oxide, lanthanum oxide, and magnesium oxide. These can be used alone or in combination of two or more. Among these, silicon oxide has high transparency with respect to light emission from the phosphor and wavelength-converted light from the phosphor, suppresses deterioration of the phosphor particles received from the environment, and glass powder when forming a glass layer. High affinity is preferable in mixing.

  The thickness of the intermediate coating layer can suppress the deterioration of the phosphor particles from the environment such as water and oxygen and the deterioration in the heating process at the time of molding, and the light emission from the phosphor and the transmission of the wavelength converted light from the phosphor can be suppressed. It is preferable that the thickness is not reduced. Specifically, 100 nm to 6 μm can be mentioned, and 300 nm to 2 μm is more preferable.

  The intermediate coating layer may have one layer or two or more layers.

  As a method for forming the intermediate coating layer, a CVD method, a PVD method, a solution method, or the like can be used. Examples of the CVD method include a plasma CVD method in which a raw material gas is converted into plasma and an oxide film is formed on the surface of phosphor particles. For example, a reaction gas such as oxygen gas is supplied to a reaction tube having a vacuum degree of about 0.05 to 5 Torr, and this is used as plasma in a plasma region in which a high frequency coil or the like is disposed. On the other hand, a reactive gas such as tetramethylsilane gas is supplied to the reaction tube, and silicon oxide formed by reaction with plasma oxygen is deposited on the surface of the phosphor particles arranged in the reaction tube outside the plasma region to oxidize. A silicon coating is formed.

  In the solution method, these metal alkoxide solutions are prepared from lower fatty acid salts of yttrium and aluminum, for example, propionate and ethanol. Examples include a method in which a sulfide-based phosphor is dispersed and coated in a metal alkoxide solution, heated as necessary, and a coating having a desired thickness is formed to form oxide-coated phosphor particles. it can. Also, disperse and apply sulfide-based phosphor in a solution obtained by mixing ethanol, water, and ammonia with tetraethoxysilane, and repeat heating as necessary to form oxide-coated phosphor particles. can do. Moreover, the dispersion liquid which disperse | distributed sulfide type fluorescent substance in the metal alkoxide solution can be made into a particulate form with a spray dryer, and an oxide covering fluorescent particle can be obtained.

The glass layer provided on the phosphor particles via the intermediate coating layer determines the outer shape of the phosphor member. The outer shape of the phosphor member is asymmetric, that is, each phosphor member has a certain shape. In order to avoid this, it has various shapes and is formed so as not to have the same size. The glass layer is a glass layer having a predetermined thickness or asymmetric thickness profile covers the phosphor particles asymmetric. Due to the asymmetry of the outer shape of the glass layer, the wavelength-converted light of various wavelengths emitted from various fluorescent materials contained in the phosphor particles is diffused and mixed, and further, excitation light emitted from the light emitter. And color unevenness of light emitted from a light emitting element using the same can be suppressed.

  The asymmetric thickness of the glass layer can be detected using an electron microscope (SEM).

  As the glass contained in the glass layer, a high-density one having a high encapsulation effect of the phosphor particles having the intermediate coating layer is preferable because the deterioration of the phosphor particles can be suppressed, and the molding temperature is low. Those are preferable because deterioration of phosphor particles during molding can be suppressed. Specifically, the glass contained in the glass layer is preferably one containing silicic acid, boric anhydride, boric acid, or anhydrous borax as a main component.

As a method of forming such a glass layer, by mixing a glass powder for forming phosphor particles and a glass layer coated with the intermediate coating layer, the resulting mixture was formed into sheet over preparative shape, then, by sintering to obtain a sintered body, and pulverizing the sintered body, by a method of sieving. The mixing ratio of the phosphor particles and the glass powder coated with an intermediate coating layer, relative to the mass of the phosphor particles between coated with a coating layer medium, the mass of the glass powder and 4-7 times. The specific gravity of the phosphor is about 2 to 3 times the specific gravity of the glass, and the glass powder is contained in the mixture in a mass range of 4 to 7 times the mass of the phosphor particles coated with the intermediate coating layer. Then, the glass layer having the above thickness can be formed.

  This mixture can be mixed with a binder or the like as required. Any binder can be used as long as it can disperse phosphor particles coated with glass powder and an intermediate coating layer, and can be decomposed and removed during firing, but a resin having an appropriate viscosity should be used. Can do. In addition, the mixture may contain phosphor particles coated with the intermediate coating layer, substances that lower the glass molding temperature, and the like within a range that does not impair the function of the glass powder.

Shaping of the mixture, press molding method, molding method, may be a coating method such as any of the methods, the thickness Saga 0.2Mm～2m m, good Mashiku is about 0.5mm~1mm sheet Forming in the shape does not hinder the transmission of excitation light from the light emitter in the formed phosphor member, and can suppress a decrease in the light conversion intensity of light emitted from the phosphor. The firing temperature in the subsequent firing step can be appropriately selected depending on the material, and it is necessary to be a temperature at which the particles of the glass powder can be sufficiently melted to encapsulate the phosphor particles coated with the intermediate coating layer. For example, 370-650 degreeC etc. can be mentioned, 400-500 degreeC is preferable. Even when the firing temperature is high, the phosphor particles are protected by the intermediate coating layer and the deterioration is suppressed.

  The sintered body may be pulverized by a general method such as a ball mill method or a jet mill method. Examples of the ball mill method include a method of mixing and pulverizing a solvent such as pure water or an alcohol such as ethanol and a ceramic pole made of a material such as soot, alumina, and zirconia together with a sintered body in a ceramic pot. be able to. Examples of the jet mill method include a method in which sintered bodies collide with each other in high-pressure air.

The outer shape of the phosphor members of the present invention is determined by the glass layer, although the outer shape is asymmetric, the maximum diameter is 100μm or more 3mm or less. The maximum major axis is the length of the longest diagonal if the outer shape of the phosphor member is polygonal, the length of the rod if it is rod-like, and the length of the longest diagonal of the plane if flat. If it is spherical, the maximum diameter is applicable. When the maximum major axis is in the above range, it is possible to diffuse the fluorescence from the phosphor particles.

  As an example of the phosphor member of the present invention, one shown in the schematic configuration diagram of FIG. 1 can be exemplified. The phosphor member 1 shown in the perspective view of FIG. 1A and the plan view of FIG. 1B includes phosphor particles 2, an intermediate coating layer 3 that sequentially covers the periphery thereof, and a glass layer 4. In FIG. 1A, the intermediate coating layer is not shown.

  The light emitting device of the present invention includes a light emitter and the fluorescent member.

As an example of the light-emitting element of the present invention, the light-emitting element shown in the schematic cross-sectional view of FIG. 2A and the schematic top view of FIG. The light-emitting element shown in FIG. 2 mainly includes a housing 12 having a reflector function, an LED chip 13 which is a light emitter fixed on a submount (not shown) fixed to the housing, and an LED. The transparent resin body 14 surrounding the chip and the phosphor member 1 are fixed by a sealing film 15 so as to cover the transparent resin body 14. The LED chip 13 is preferably formed of a gallium nitride compound semiconductor that emits blue light in which an InGaN light emitting layer is laminated on an Al ₂ O ₃ or SIO substrate. The LED of the LED chip has its electrodes wire-bonded by wiring 16 and is electrically connected to a power source (not shown) to emit blue / ultraviolet light.

  For example, an epoxy resin, a urea resin, a silicone resin, or the like that is provided for protecting the LED chip, has excellent light transmission from the LED, and has resistance to the energy, is preferably used. The sealing film that seals the phosphor member on the upper surface of the transparent resin body preferably has a high transmittance with respect to the light from the LED and the wavelength-converted light from the phosphor member, and the deterioration is preferably suppressed. A resin similar to the resin used for the body 14 can be used. The sealing film is made of a laminate film of nylon, PET, fluororesin, or the like, and its end is fixed to the casing by thermocompression bonding or the like to seal the phosphor member.

  In such a light emitting device, the phosphor contained in the phosphor member is excited by the light from the LED to emit wavelength-converted light, and this wavelength-converted light is diffused by the glass layer, and further emitted from the LED and diffused. The light is mixed and white light is emitted from the surface of the light emitting element.

  Another example of the light emitting element of the present invention is the one shown in the schematic configuration diagram of FIG. The light emitting element shown in FIG. 3 mainly includes an LED chip 23 that is a light emitter fixed to the concave portion on the metal stem 22, a transparent resin body 24 provided in the concave portion so as to surround the LED chip 23, and a transparent A sealing film 21 in which the phosphor member is sealed is provided so as to cover the resin body. The LED chip 23 may include an LED such as a gallium nitride compound semiconductor. The LED of the LED chip is electrically connected to a power source (not shown) via a metal post 25 connected by wiring, and emits blue / ultraviolet light. Further, a metal stem for mounting the LED chip and a mold resin body 26 for molding the metas post are provided.

  The transparent resin body is provided to protect the LED chip, and the mold resin body has a lens function for diffusing the light emitted from the LED element, and these resins have excellent light transmission from the LED. For example, an epoxy resin, a urea resin, a silicone resin or the like having resistance to the energy is preferably used. The phosphor contained in the phosphor member sealed by the sealing film 21 provided on the upper surface of the transparent resin body is excited by the light from the LED to emit wavelength converted light, and this wavelength converted light is emitted from the phosphor member. The light is diffused by the glass layer and further diffused and mixed with the light emitted from the LED, and white light is emitted from the surface of the mold resin body.

  Another example of the light emitting device of the present invention is the one shown in the schematic configuration diagram of FIG. The light emitting device shown in FIG. 4 mainly includes an LED which is a light emitter fixed on a substrate 32 having a concave portion having a reflector function and a submount (not shown) fixed to the bottom surface of the concave portion of the substrate. A chip 33, an optical member 34 having a lens function on a concave portion of the substrate on which the LED chip 33 is provided, and a sealing member in which the phosphor member is sealed on the lower surface of the optical member 34 so as to face the LED chip. A stop film 31 is provided. The LED chip 33 may include an LED that emits the blue light. The LED of the LED chip is wire-bonded with a wiring (not shown), connected to a power source (not shown) and electrically connected to emit blue / ultraviolet light.

  In the concave portion of the substrate 32 on which the LED chip 33 is provided, for protecting the LED chip, it has excellent light transmission from the LED and has resistance to energy, such as epoxy resin, urea resin, silicone resin, etc. A transparent resin may be provided. The phosphor contained in the phosphor member sealed in the sealing film 31 is excited by light from the LED to emit wavelength converted light, and this wavelength converted light is diffused in the glass layer, and further from the LED. The light is diffused and mixed to emit light, and the emission direction is further diffused by the optical member 34 so that white light is emitted from the surface.

As another example of the light emitting device of the present invention, the one shown in the schematic configuration diagram of FIG. 5 can be cited. The light emitting device shown in FIG. 5 mainly includes a substrate 42, a pair of leads 43 fixed to the substrate, an LED chip 44 which is a light emitter fixed on one of the leads, and the LED chip 44. A surrounding transparent resin body 45 and a sealing film 41 in which the phosphor member is sealed so as to cover the transparent resin body are provided. The LED chip 44 may include an LED such as a gallium nitride compound semiconductor that emits blue light in which an InGaN light emitting layer is laminated on an Al ₂ O ₃ or SIO substrate. The LED of the LED chip is connected to the other lead by wiring 46 and is electrically connected to a power source (not shown), and emits blue / ultraviolet light.

  For example, an epoxy resin, a urea resin, a silicone resin, or the like that is provided for protecting the LED chip, has excellent light transmission from the LED, and has resistance to the energy, is preferably used. The phosphor contained in the phosphor member sealed by the sealing film 41 provided on the upper surface of the transparent resin is excited by light from the LED to emit wavelength converted light, and this wavelength converted light is emitted by the glass layer. The light is diffused and further diffused and mixed with the light emitted from the LED, and white light is emitted from the surface of the light emitting element.

  The lighting device of the present invention may be any one as long as it has the above light-emitting element. For example, a lighting for an automobile lamp, various display backlights, downlights, spotlights, etc. Can be mentioned.

It is a schematic block diagram which shows an example of the phosphor member of this invention. It is a schematic block diagram which shows an example of the light emitting element of this invention. It is a schematic block diagram which shows the other example of the light emitting element of this invention. It is a schematic block diagram which shows the other example of the light emitting element of this invention. It is a schematic block diagram which shows the other example of the light emitting element of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Phosphor member 2 Phosphor particle 3 Intermediate coating layer 4 Glass layer 15 Sealing film

Claims (6)

A phosphor particle that emits wavelength-converted light when excited by light emitted from the phosphor, an intermediate coating layer that covers the phosphor particle, and a glass layer that includes glass that covers the intermediate coating layer, and has a median diameter 4 but 10μm or more, with respect to the maximum major diameter of the phosphor particles 10 to 100 times the outer shape coated with and the intermediate coating layer as to cover the asymmetric phosphor particles in the intermediate coating layer of the median diameter by mass in 30μm or less A glass layer is formed by pulverizing a sintered body obtained by forming and sintering a mixture containing glass powder having a mass of ˜7 times into a sheet having a thickness of 0.2 mm to 2 mm, and a maximum major axis of 100 μm to A phosphor member having an asymmetric outer shape formed to 3 mm.   2. The phosphor member according to claim 1, wherein the phosphor particles include a plurality of kinds of phosphors and emit white light. The phosphor member according to claim 1 or 2, wherein the glass layer has an asymmetric thickness around the phosphor particles . A light-emitting element comprising a light-emitting body and the fluorescent member according to claim 1. The light emitting device according to claim 4, wherein the phosphor member is fixed by a sealing film. An illumination device comprising the light emitting element according to claim 4.

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