JP6990065B2 - Wavelength conversion member, its manufacturing method and light emitting device - Google Patents

Description

The present invention relates to a wavelength conversion member that converts light having a specific range of wavelengths into light having another wavelength, a method for manufacturing the same, and a light emitting device.

As a light emitting device using a phosphor, an increasing number of applications use a high-power laser diode (LD) as an excitation source. Such an application has high energy efficiency and is easy to cope with the miniaturization of the device and the high energy density (10 to 200 W / mm ² ) of the laser. However, in the phosphor layer having a structure in which the phosphor particles are dispersed in a resin typified by an epoxy or silicone that has been conventionally used, the resin at the laser irradiation site is burnt and a high-power laser diode (LD) is used. It could not be used in the application used as an excitation source.

To this end, there is a method of improving heat resistance by using an inorganic binder for the fluorescent material layer. The fluorescent material layer using the inorganic binder can be produced, for example, as follows. First, the fluorescent powder is mixed with a dispersion solvent, and an inorganic binder is added to prepare a paste. Then, a paste is applied by a screen printing method to form a film on the base material, and the film is fired to form a phosphor layer using an inorganic binder.

As an application example of a phosphor layer using such an inorganic binder, a phosphor plate provided in an LED element mounted on a circuit board and converting blue light into white is known (Patent Document 1). Further, a method is known in which phosphor particles are mixed with polysilazane containing inorganic fine particles as a raw material to prepare a fluorescent plate having a fluorescent layer using an inorganic binder (Patent Document 2).

Japanese Unexamined Japanese Patent Publication No. 2004-200531 International Publication No. 2011/07548

As described above, the wavelength conversion member provided with the phosphor layer using the inorganic binder has heat resistance in its structure itself. However, when such a wavelength conversion member is irradiated with a laser having a high output and a high energy density, the temperature becomes locally high, and the emission performance of the phosphor particles deteriorates due to temperature quenching.

The present invention has been made in view of such circumstances, and provides a wavelength conversion member capable of suppressing deterioration of light emission performance due to temperature quenching when irradiated with a laser having a high energy density, a manufacturing method thereof, and a light emitting device. The purpose is.

(1) In order to achieve the above object, the wavelength conversion member of the present invention is a wavelength conversion member that converts light having a specific range of wavelength into light having another wavelength, and has a first base material and the first base material. A second base material facing the base material 1 and a phosphor particle and the fluorescence provided on the surface of the first base material facing the second base material and emitting conversion light with respect to absorbed light. A phosphor layer made of an inorganic material that binds body particles to each other and transmits visible light, and a sealing portion that seals a region sandwiched between the first base material and the second base material are provided. , The phosphor layer and the second base material are filled with a fluid that transmits visible light, and at least one of the first and second base materials transmits visible light. It is characterized by that.

As a result, the heat generated at the time of light emission of the phosphor particles can be efficiently released to the second base material through the fluid, and light can be transmitted in the fluid. As a result, it is possible to suppress a decrease in light emission performance due to temperature quenching when irradiating a laser having a high energy density.

(2) Further, in the wavelength conversion member of the present invention, the fluid is added between the phosphor layer and the second base material, and the first base material and the second base material are used. It is characterized in that the first base material and the second base material are arranged in contact with each other. As a result, the heat generated when the phosphor particles emit light can be widely diffused to the outside of the phosphor layer and transferred to the second substrate, so that performance deterioration can be suppressed.

(3) Further, the wavelength conversion member of the present invention is characterized in that the thermal conductivity of the fluid is 0.5 W / (m · K) or more at 25 ° C. As a result, the heat generated in the phosphor layer via the fluid can be released to the second base material.

(4) Further, the wavelength conversion member of the present invention is characterized in that the light absorption rate of the fluid at the excitation wavelength and the fluorescence wavelength is 15% or less. In this way, the fluid maintains thermal conductivity and has low absorbance, so that light can be extracted with high efficiency.

(5) Further, the wavelength conversion member of the present invention is characterized in that the mixing consistency of the fluid is 200 or more and 400 or less in a temperature range of 25 ° C. or less. As described above, the fluid has fluidity and is filled in the gaps between the phosphor layer and the second base material and some of the phosphor particles constituting the phosphor layer, so that the second substrate from the phosphor layer is filled. Heat can be efficiently dissipated to the substrate. Further, since the fluid is held in the gap by having a viscosity of a certain level or higher, it is easy to handle even at the time of manufacturing.

(6) Further, the wavelength conversion member of the present invention is characterized in that the fluid is in close contact with the surface of the phosphor layer and has entered the communication hole connected from the surface to the inside. Since the fluid has penetrated into the communication holes on the surface of the phosphor layer in this way, the contact area between the phosphor layer and the fluid is increased, and the thermal conductivity can be improved.

(7) Further, in the wavelength conversion member of the present invention, the fluid contains a resin having fluidity at 25 ° C. and a filler formed of an inorganic material dispersed in the resin, and the filler is the filler. It is characterized in that it is present in the fluid body in terms of volume ratio (outer division) of 30 Vol% or more and 70 Vol% or less. As described above, the presence of a filler having a constant content in the fluid enhances the thermal conductivity and maintains the transmission of visible light.

(8) Further, the wavelength conversion member of the present invention is characterized in that the material of the first base material is sapphire and the material of the second base material is aluminum. As a result, the heat generated at the boundary between the sapphire base material and the phosphor layer can be released to the aluminum base material via the fluid.

(9) Further, the wavelength conversion member of the present invention is characterized in that the material of the first base material and the second base material is sapphire. As a result, the heat generated at the boundary between the sapphire base material and the phosphor layer can be released to the other sapphire base material via the fluid.

(10) Further, the light emitting device of the present invention is a light emitting device including a light source that generates light of a light source having a wavelength in a specific range, and absorbs the light source light, converts it into light of another wavelength, and emits light. It is characterized by including the wavelength conversion member according to any one of 1) to (9). This makes it possible to realize a light emitting device that can maintain fluorescence performance even when irradiated with high-intensity light source light.

(11) Further, the method for manufacturing a wavelength conversion member of the present invention is a method for manufacturing a wavelength conversion member that converts light having a specific range of wavelengths into light having another wavelength, and is a first base material made of an inorganic material. On the other hand, a step of applying a paste in which an inorganic binder, a dispersion medium and a phosphor particle are mixed, and a step of forming a phosphor layer by drying and heat-treating the paste applied on the first substrate. It is characterized by including a step of injecting a fluid into the phosphor layer and a step of sealing between the second base material and the first base material. As a result, it is possible to manufacture a wavelength conversion member that can efficiently dissipate heat to the irradiation of light having a high energy density and suppress the temperature quenching of the phosphor layer.

According to the present invention, the heat generated at the time of light emission of the fluorescent substance particles can be efficiently dissipated to the second base material through the fluid, and light can be transmitted in the fluid. As a result, it is possible to suppress a decrease in light emission performance due to temperature quenching when irradiating a laser having a high energy density.

It is sectional drawing which shows the wavelength conversion member of 1st Embodiment. It is a schematic diagram which shows the reflection type light emitting device of 1st Embodiment. It is a schematic diagram which shows the manufacturing process of the wavelength conversion member of 1st Embodiment in each of (a), (b), (c), (d). It is sectional drawing which shows the wavelength conversion member of 2nd Embodiment. It is a schematic diagram which shows the transmission type light emitting device of 3rd Embodiment. It is a schematic diagram which shows the reflection type evaluation system for a wavelength conversion member. It is a graph which shows the emission intensity with respect to the laser power density of each sample.

Next, an embodiment of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference number is assigned to the same component in each drawing, and duplicate description is omitted. In the configuration diagram, the size of each component is conceptually represented, and does not necessarily represent the actual dimensional ratio.

(First Embodiment)
[Structure of wavelength conversion member]
FIG. 1 is a cross-sectional view showing a wavelength conversion member 100. The wavelength conversion member 100 includes a transmission material 110 (first base material), a phosphor layer 120, a reflector 130 (second base material), a fluid body 140, and a sealing portion 150, and is formed in a plate shape. There is. The first base material refers to a base material that is in direct contact with the phosphor layer, and the second base material refers to a base material that is in contact with the phosphor layer via a fluid. The base material is called a transmissive material or a reflective material depending on whether it reflects. The wavelength conversion member 100 converts light having a wavelength in a specific range into light having another wavelength by the light source while reflecting the light from the light source by the reflector 130.

(Transparent material)
The transmissive material 110 is made of an inorganic material and transmits light. The transmissive material 110 preferably has a higher thermal conductivity than the phosphor layer 120. By adopting the transmissive material 110 having high thermal conductivity, the heat in the phosphor layer 120 can be released, the temperature rise of the phosphor particles can be suppressed, and the temperature quenching can be prevented. As the transmissive material 110, a translucent material such as sapphire or glass can be used, and it is particularly preferable that the transmissive material 110 is made of sapphire. This makes it possible to maintain high thermal conductivity while transmitting light.

(Reflective material)
The reflective material 130 can be formed of a plate-shaped inorganic material that reflects light such as metal such as aluminum, iron, and copper, and is particularly preferably an aluminum plate. The reflective material 130 (second base material) is provided so as to face the transmissive material 110 (first base material). The reflective material 130 may be mirror-finished in order to increase the reflectance, or may be provided with a highly reflective film (for example, Ag coat). Further, a glass or sapphire coated with a mirror may be used as the reflective material 130, or may be provided by plating or the like. The reflective material 130 is arranged on the opposite side of the transmissive material 110, and the surface (opposing surface of the transmissive material 110) is used as a reflective surface for the converted light. For example, the reflective material 130 can reflect the light source light of blue light and also reflect and radiate the fluorescence of green, red, and yellow converted by the phosphor layer 120.

In the example shown in FIG. 1, the reflective material 130 and the transmissive material 110 provided with the phosphor layer 120 are restrained by a sealing portion 150 which is an adhesive. Further, as described later, it may be restrained by a holder that fastens the outer circumference by an external force. Since the phosphor layer 120 and the reflective material 130 are not directly fixed to each other, it is possible to prevent destruction due to a difference in thermal expansion. Since the adhesive is applied partially instead of the entire surface, it can be sufficiently suppressed from being peeled off due to the difference in thermal expansion.

(Fluorescent layer)
The phosphor layer 120 is provided on the surface of the transparent material 110 (first base material) facing the reflective material 130 (second base material) as a film bonded to the transparent material 110. The phosphor layer 120 is formed of phosphor particles 122 and a translucent inorganic material 121. The inorganic material 121 binds the phosphor particles 122 to each other and also bonds the transmissive material 110 and the phosphor particles 122. As a result, the portion where heat is likely to be generated on the irradiation side is directly bonded to the transmitting material 110 that functions as a heat radiating material for irradiation with high energy density light, so that heat can be efficiently radiated and the temperature of the phosphor is extinguished. Can be suppressed. The phosphor layer 120 is composed of phosphor particles 122 and an inorganic material 121. The phosphor particles 122 emit conversion light with respect to the absorbed light, and the inorganic material 121 transmits visible light.

Since the fluorescent material layer 120 is bonded to the transparent material 110 by a chemical bond, the heat conduction from the fluorescent material layer 120 to the transparent material 110 is high. Further, the reflector 130 and the reflector layer 120 are in contact with each other via the fluid 140, and the difference in thermal expansion between the reflector layer 120 and the reflector 130 is alleviated by the fluidity of the fluid 140. Further, the fluid 140 can effectively dissipate the heat of the phosphor layer 120 to the reflective material.

The inorganic material 121 is an inorganic binder for holding the phosphor particles 122, and is composed of, for example, silica (SiO ₂ ) and aluminum phosphate. For the phosphor particles 122, for example, yttrium aluminum garnet phosphor (YAG phosphor) and lutetium aluminum garnet phosphor (LAG phosphor) can be used.

In addition, the phosphor particles can be selected from the following materials according to the design of the color to be emitted. For example, a blue phosphor such as BaMgAl ₁₀ O ₁₇ : Eu, ZnS: Ag, Cl, BaAl ₂ S ₄ : Eu or CaMgSi ₂ O ₆ : Eu, Zn ₂ SiO ₄ : Mn, (Y, Gd) BO ₃ : Tb, ZnS: Cu, Al, (M1) ₂ SiO ₄ : Eu, (M1) (M2) ₂ S: Eu, (M3) ₃ Al ₅ O ₁₂ : Ce, SiAlON: Eu, CaSiAlON: Eu, (M1) Si ₂ O ₂ N: Eu or (Ba, Sr, Mg) ₂ SiO ₄ : Yellow or green phosphor such as Eu, Mn, (M1) ₃ SiO ₅ : Eu or yellow such as (M1) S: Eu, Orange or red phosphor, (Y, Gd) BO ₃ : Eu, Y ₂ O ₂ S: Eu, (M1) ₂ Si ₅ N ₈ : Eu, (M1) AlSiN ₃ : Eu or YPVO ₄ : Eu, etc. Examples include red phosphors. In the above chemical formula, M1 contains at least one of the group consisting of Ba, Ca, Sr and Mg, M2 contains at least one of Ga and Al, and M3 contains Y, Gd and. At least one of the group consisting of Lu and Te is included. The above-mentioned fluorescent particles are an example, and the fluorescent particles used for the wavelength conversion member are not necessarily limited to the above. With such a configuration, the phosphor layer 120 can be freely converted to a designated color by irradiating the phosphor layer 120 with blue light using a laser diode (LD) as an excitation source and using a plurality of phosphor particles.

The fluid 140 is filled between the phosphor layer 120 and the reflective material 130 (second base material) and transmits visible light. As a result, the heat generated at the boundary between the transmissive material 110 and the phosphor layer 120 when the phosphor particles emit light is efficiently released to the reflective material 130 (second base material) through the fluid 140, and the fluid is fluid. Light can be transmitted within 140. As a result, even if a laser having a high energy density is irradiated, deterioration of the light emitting performance of the wavelength conversion member due to temperature quenching can be suppressed. The fluid 140 is preferably a resin having fluidity such as thermal paste (for example, grease containing ceramic or metal particles (filler) to enhance heat dissipation). The phosphor layer 120 and the reflective material 130 may be filled with the fluid 140 in the gaps where the irregularities on the surfaces of the phosphor layer 120 and the reflective material 130 are in contact with each other.

The fluid 140 is in close contact with the surface of the phosphor layer 120 and has entered the communication holes connected from the surface to the inside. Since the fluid 140 has entered the communication holes on the surface of the fluorescent layer 120 in this way, the contact area between the fluorescent layer 120 and the fluid 140 is increased, and the thermal conductivity can be improved.

The fluid 140 is added between the phosphor layer 120 and the reflective material 130 (second base material), and between the transmissive material 110 (first base material) and the reflective material 130 (second base material). It is preferable that they are arranged in contact with both base materials. As a result, the heat generated when the phosphor particles emit light can be widely diffused to the outside of the phosphor layer 120 and transmitted to the reflector 130, and the performance deterioration due to temperature quenching can be suppressed.

The thermal conductivity of the fluid 140 is preferably 0.5 W / (m · K) or more, and more preferably 0.8 W / (m · K) or more at 25 ° C. As a result, the heat generated in the phosphor layer 120 via the fluid 140 can be efficiently dissipated to the reflective material 130 (second base material). For example, when the fluid 140 is not provided and the portion is filled with dry air, the thermal conductivity of the dry air is 0.0241 W / (m · K), and the thermal conductivity is low, so that the heat is efficient. It becomes difficult to escape to the reflective material 130 (second base material).

The light absorption rate of the fluid 140 at the excitation wavelength and the fluorescence wavelength is preferably 15% or less. In this way, the fluid 140 maintains thermal conductivity and has low absorbance, so that light can be extracted with high efficiency. The excitation wavelength referred to here is the wavelength of light emitted from an excitation source (laser or the like), and the fluorescence wavelength is the wavelength of light emitted from the phosphor layer in response to the light of the excitation source. Absorbance can be measured by applying a fluid 140 to a sapphire substrate and measuring it with a spectrophotometer (JIS K 0115: 2004 Absorbance Analysis General Rules).

The mixing consistency of the fluid 140 is 200 or more and 400 or less, preferably 300 or more, in a temperature range of 25 ° C. or less. The miscibility is the consistency (JISK 2220) immediately after the thermal paste is mixed by a specified mixer for 60 reciprocations, and is used as an index showing the hardness and fluidity of the thermal paste. Since the fluid 140 has fluidity and is filled in the gaps in this way, heat can be efficiently dissipated from the phosphor layer 120 to the reflector 130 (second base material). Further, since the fluid 140 is held in the gap by having a viscosity of a certain level or higher, it is easy to handle even at the time of manufacturing.

The fluid 140 preferably contains a resin having fluidity at 25 ° C. and a filler formed of an inorganic material dispersed in the resin. The filler is preferably composed of a ceramic that transmits visible light, such as alumina, titania, and zinc oxide. Further, it is preferable that the filler is present in the fluid 140 in a volume ratio (outer division) of 30 Vol% or more and 70 Vol% or less. As described above, the presence of the filler having a constant content in the fluid 140 maintains the transmission of visible light while increasing the thermal conductivity.

The sealing portion 150 seals a region sandwiched between the transparent material 110 (first base material) and the reflective material 130 (second base material). The sealing portion 150 is composed of, for example, an adhesive. As the adhesive, a thermosetting resin such as an epoxy resin can be used.

[Configuration of light emitting device]
FIG. 2 is a schematic view showing a reflection type light emitting device 10. As shown in FIG. 2, the light emitting device 10 includes a light source 50 and a wavelength conversion member 100, and for example, the light source light reflected by the wavelength conversion member 100 and the light generated by excitation by the light source light in the wavelength conversion member 100 are combined. It emits irradiation light. The irradiation light can be, for example, white light.

As the light source 50, an LED (Light Emitting Diode) or LD (Laser Diode) chip can be used. The LED generates light source light having a wavelength in a specific range according to the design of the light emitting device 10. For example, LEDs generate ultraviolet, purple or blue light. Further, when LD is used, coherent light with little variation in wavelength and phase can be generated. The light source 50 is not limited to these, and may be one that generates light other than visible light, but a light source that generates ultraviolet light, purple light, blue light, or green light is preferable. Such a light emitting device 10 is expected to be highly effective when applied to lighting of public facilities that illuminate a wide range from high places such as factories, stadiums and museums, or lighting that illuminates a long distance such as headlamps of automobiles.

[Method of manufacturing wavelength conversion member]
3 (a), (b), (c), and (d) are schematic views showing a manufacturing process of a wavelength conversion member, respectively. First, prepare an inorganic binder, a dispersion medium, and phosphor particles. As a preferable inorganic binder, for example, ethyl silicate obtained by dissolving a silicon precursor in ethanol can be used.

In addition, the inorganic binder is prepared by reacting a raw material containing at least one of a group consisting of a silicon oxide precursor, a silicic acid compound, silica, and amorphous silica, which becomes silicon oxide by hydrolysis or oxidation, at room temperature. , It may be obtained by heat treatment at a temperature of 500 ° C. or lower. Examples of the silicon oxide precursor include those containing perhydropolysilazane, ethyl silicate, and methyl silicate as main components.

Further, as the dispersion medium, a high boiling point solvent such as butanol, isophorone, terpineol, and glycerin can be used. As the phosphor particles, for example, particles such as YAG and LAG can be used. The type and amount of phosphor particles are adjusted according to the irradiation light to be obtained with respect to the light source light. For example, when trying to obtain white light with respect to blue light, an appropriate amount of phosphor particles that emit green light and red light or yellow light when excited by blue light is selected.

As shown in FIG. 3A, these inorganic binders, dispersion mediums, and phosphor particles are mixed to prepare a paste (ink) 410. A ball mill or the like can be used for mixing. On the other hand, a transparent material 110 made of an inorganic material is prepared. Glass or sapphire can be used for the transparent material 110. The transparent material 110 is preferably plate-shaped.

Next, as shown in FIG. 3B, the obtained paste 410 is applied to the transparent material 110 by using a screen printing method. Screen printing can be performed by pressing the paste 410 with the ink squeegee 510 against the silk screen 520 stretched on the frame. In addition to the screen printing method, a spray method, a drawing method using a dispenser, and an inkjet method can be mentioned, but the screen printing method is preferable in order to stably form a thin phosphor layer. In addition, not limited to printing, other coating methods may be performed.

Then, the printed paste 410 is dried and heat-treated in the furnace 600 to remove the solvent and the organic component of the inorganic binder to oxidize the main metal in the inorganic binder (SiO ₂ when the main metal is Si). At that time, the phosphor layer 120 and the transmissive material 110 are adhered to each other. The paste printed on the transparent material 110 in this way is dried and heat-treated to form a phosphor layer. Then, the fluid 140 is injected onto the surface of the phosphor layer. For example, thermal paste is applied on the surface of the phosphor layer as the fluid 140.

A reflective material 130 made of an inorganic material that reflects light is arranged on the phosphor layer 120 and adhered. In this way, the space between the transparent material 110 (first base material) and the reflective material 130 (second base material) is sealed. As a result, it is possible to manufacture the wavelength conversion member 100 that can efficiently dissipate heat to the irradiation of light having a high energy density and suppress the temperature quenching of the phosphor. The light emitting device can be manufactured by arranging the wavelength conversion member so that it can receive light from a light source such as an LED.

(Second embodiment)
In the above embodiment, the transmissive material 110 (first base material) and the reflective material 130 (second base material) are bonded and sealed by a sealing portion 150 made of an adhesive. For example, an O-ring is used. An annular elastic body such as the above may be used as a sealing material for the sealing portion, and both base materials may be restrained by a holder that fastens the outer periphery.

FIG. 4 is a cross-sectional view showing a wavelength conversion member using the O-ring 250 and the holder 260. As shown in FIG. 4, the structure in which the phosphor layer 120 is sandwiched between the transparent material 110 and the reflective material 130 is restrained by the holder 260 from the outside. An O-ring 250 (sealing portion) is bitten between the holder 260 and the transmissive material 110 and between the holder 260 and the reflective material 130, respectively, to seal the fluid 140.

(Third embodiment)
In the above embodiment, the second base material is formed of a reflective material, but both the first base material and the second base material may be a transmissive material. In that case, sapphire is preferable as the material of the transparent material. The heat generated at the boundary between the transmissive material and the phosphor layer can be released to the other transmissive material via the fluid 140.

FIG. 5 is a schematic diagram showing a transmissive light emitting device 20. As shown in FIG. 5, the light emitting device 30 includes a light source 50 and a wavelength conversion member 300, and irradiates the light source light transmitted by the wavelength conversion member 300 and the fluorescence generated by excitation by the light source light in the wavelength conversion member 100 together. It emits light.

The wavelength conversion member 300 includes a transmission material 110 (first base material), a phosphor layer 120, a transmission material 330 (second base material), a fluid body 140, and a sealing portion 150, and is formed in a plate shape. There is. The phosphor layer 120 is provided on the surface of the transparent material 110 (first base material) facing the transparent material 330 (second base material) as a film bonded to the transparent material 110. The transparent material 330 (second base material) is provided facing the transparent material 110 (first base material), and is formed of sapphire or the like like the transparent material 110 (first base material). Is preferable. Since the position where the light source light is incident on the phosphor layer tends to generate heat, there is a bonding surface between the transmissive material 110 (first base material) and the phosphor layer on the light source light side, and the fluid is on the side that emits the irradiation light. It is preferable that 140 is filled. However, the arrangement may be reversed.

[Example]
(1) Sample preparation method Wavelength conversion members of Examples and Comparative Examples were prepared. First, ethyl silicate and terpineol were mixed with YAG phosphor particles (average particle diameter 6 μm) to prepare a paste.

The prepared paste was applied to a sapphire plate as a transparent material to a thickness of 20 μm by a screen printing method, and heat-treated to obtain an intermediate member. At this time, two sapphire plates were subjected to the same conditions to obtain two intermediate members.

A wavelength conversion member as an example was produced by injecting a fluid into one intermediate member, placing a reflective material of an aluminum plate on it, and adhering it to a transmissive material. Thermal paste (silicon-based) was uniformly applied to the surface of the phosphor layer of the intermediate member. At that time, the thickness was adjusted to be about 20 μm. As the fluid in the examples, silicon for heat dissipation (SCH-30) manufactured by Sanhayato Co., Ltd. was used. An adhesive that does not peel off due to heat of 300 ° C. or higher was applied to the outer peripheral portion of the sapphire base material on the side of the intermediate member where the phosphor layer was not provided so as not to touch the phosphor layer with a thickness of the phosphor layer or more. Then, the aluminum substrate was attached to the surface coated with the thermal paste and the adhesive, and heat-treated at 300 ° C. in the air to fix it. In this way, the wavelength conversion member as an example was produced.

Further, without injecting a fluid into the other intermediate member, the reflective material of the aluminum plate was similarly adhered to the transmissive material via an adhesive to prepare a wavelength conversion member as a comparative example. In this comparative example, the fluorescent material layer and the reflective material were placed in contact with each other, but due to the unevenness of the surface of the fluorescent material layer, the fluorescent material layer and the reflective material were only partially in contact with each other.

(2) Evaluation method The emission intensity was evaluated with respect to the Examples and Comparative Examples obtained as described above. Specifically, the sample was irradiated with a laser, and the emission intensity of fluorescence with respect to the laser input value was examined. A laser having a wavelength of 445 nm was irradiated with an input of 2 W, and the emission intensity was measured. The irradiation diameter was adjusted to 0.03 mm ² with a condenser lens. The emission intensity of fluorescence is a relative intensity obtained by making the numerical value shown on the luminance meter non-dimensional when the above evaluation system is used.

FIG. 6 is a schematic diagram showing a reflection type evaluation system 700 for a wavelength conversion member. As shown in FIG. 6, the reflection type evaluation system 700 includes a light source 710, a planar convex lens 720, a biconvex lens 730, a bandpass filter 735, and a power meter 740. Each element is arranged so that the reflected light from the wavelength conversion member 100 can be collected and measured.

The bandpass filter 735 is a filter that cuts light having a wavelength of 480 nm or less, and is located between a biconvex lens and a power meter in order to separate the transmitted light source light (excitation light) from fluorescence when measuring the emission intensity of fluorescence. Will be installed in.

The light source light entering the planar convex lens 720 is focused on the focal point on the sample S of the wavelength conversion member. Then, the synchrotron radiation generated from the sample S is focused by the biconvex lens 730, and the intensity of the focused light having a wavelength of 480 nm or less cut is measured by the power meter 740. This measured value is taken as the emission intensity of fluorescence. By condensing the laser beam with a lens and narrowing the irradiation area, the energy density per unit area can be increased even with a low-power laser. This energy density is referred to as the laser power density.

FIG. 7 is a graph showing the emission intensity with respect to the laser power density of each sample. In the comparative example not filled with thermal paste, the fluorescence is quenched at 40 W / mm ² , whereas in the example in which the thermal paste is filled between the aluminum plate and the phosphor layer, the fluorescence is quenched at 63 W / mm ² . Quenching was confirmed. When the examples and comparative examples were evaluated in this way, the energy input before reaching the peak indicating quenching was higher in the examples than in the comparative examples.

10, 30 Light emitting device 50 Light source 100 Wavelength conversion member 110 Transmissive material (first base material)
120 Fluorescent layer 121 Inorganic material 122 Fluorescent particles 130 Reflective material (second base material)
140 Fluid 150 Sealing part 250 O-ring (sealing part)
260 Holder 300 Wavelength conversion member 330 Transmissive material (second base material)
410 Paste 510 Ink Squeegee 520 Silkscreen 600 Furnace 700 Evaluation System 710 Light Source 720 Planar Convex Lens 730 Biconvex Lens 735 Bandpass Filter 740 Power Meter S Sample

Claims (9)

A wavelength conversion member that converts light of a specific wavelength into light of another wavelength.
With the first base material,
A second base material facing the first base material and
An inorganic material provided on the surface of the first substrate facing the second substrate and emitting conversion light with respect to absorbed light and an inorganic material that binds the fluorescent particles to each other and transmits visible light. A fluorescent layer consisting of
A sealing portion for sealing a region sandwiched between the first base material and the second base material is provided.
A fluid that transmits visible light is filled between the phosphor layer and the second base material.
Of the first and second substrates, the first substrate is a transmissive material that transmits visible light.
The second base material is a reflective material that reflects the absorbed light and the converted light.
A wavelength conversion member characterized in that the mixing consistency of the fluid is 200 or more and 400 or less in a temperature range of 25 ° C. or less . The fluid is added between the fluorescent layer and the second substrate, and between the first substrate and the second substrate, the first substrate and the second substrate. The wavelength conversion member according to claim 1, wherein the wavelength conversion member is arranged in contact with the base material of the above. The wavelength conversion member according to claim 1 or 2, wherein the thermal conductivity of the fluid is 0.5 W / (m · K) or more at 25 ° C. The wavelength conversion member according to any one of claims 1 to 3, wherein the light absorption rate of the fluid at the excitation wavelength and the fluorescence wavelength is 15% or less. The wavelength conversion member according to any one of claims 1 to 4 , wherein the fluid is in close contact with the surface of the phosphor layer and has entered the communication hole connected from the surface to the inside. The fluid contains a resin having fluidity at 25 ° C. and a filler formed of an inorganic material dispersed in the resin.
The wavelength conversion member according to any one of claims 1 to 5 , wherein the filler is present in the fluid body in a volume ratio (outer division) of 30 Vol% or more and 70 Vol% or less. The wavelength conversion member according to claim 6 , wherein the material of the first base material is sapphire, and the material of the second base material is aluminum. A light emitting device equipped with a light source that generates light from a light source having a specific wavelength range.
The light emitting device comprising the wavelength conversion member according to any one of claims 1 to 7 , which absorbs the light source light, converts it into light of another wavelength, and emits light. A method for manufacturing a wavelength conversion member that converts light having a specific wavelength into light having another wavelength.
A step of applying a paste mixed with an inorganic binder, a dispersion medium, and phosphor particles to a first base material made of an inorganic material, and a step of applying the paste.
A step of forming a phosphor layer by drying and heat-treating the paste applied on the first substrate, and
The step of injecting a fluid onto the phosphor layer and
Including a step of sealing between the second base material and the first base material.
Of the first and second substrates, the first substrate is a transmissive material that transmits visible light.
The second base material is a reflective material that reflects the absorbed light and the converted light.
The production method , wherein the mixing consistency of the fluid is 200 or more and 400 or less in a temperature range of 25 ° C. or less .

Images