JP6582907B2 - Method for manufacturing wavelength conversion element, wavelength conversion element and light emitting device - Google Patents

Description

  The present invention relates to a method of manufacturing a wavelength conversion element that converts the wavelength of light emitted from a light emitting diode (LED) or a laser diode (LD) to another wavelength, and a wavelength conversion element and a light emitting device. It is.

  In recent years, as a next-generation light-emitting device that replaces fluorescent lamps and incandescent lamps, attention has been focused on light-emitting devices using LEDs and LDs from the viewpoint of low power consumption, small size, light weight, and easy light quantity adjustment. As an example of such a next-generation light-emitting device, for example, in Patent Document 1, a wavelength conversion member that absorbs part of light from the LED and converts it into yellow light is disposed on the LED that emits blue light. A light emitting device is disclosed. This light emitting device emits white light that is a combined light of blue light emitted from the LED and yellow light emitted from the wavelength conversion member.

  As the wavelength conversion member, a material in which an inorganic phosphor powder is dispersed in a resin matrix has been conventionally used. However, when the wavelength conversion member is used, there is a problem that the resin is deteriorated by the light from the LED and the luminance of the light emitting device tends to be lowered. In particular, there is a problem that the mold resin deteriorates due to heat generated by the LED or high energy short wavelength (blue to ultraviolet) light, causing discoloration or deformation.

  Therefore, a wavelength conversion member made of a completely inorganic solid in which a phosphor is dispersed and fixed in a glass matrix instead of a resin has been proposed (see, for example, Patent Documents 2 and 3). The wavelength conversion member has a feature that glass as a base material is not easily deteriorated by the heat of LED or irradiation light, and problems such as discoloration and deformation hardly occur.

  In recent years, the output of LEDs and LDs used as light sources has increased for the purpose of increasing power. Accordingly, there is a problem that the temperature of the wavelength conversion member rises due to the heat of the light source or the heat emitted from the phosphor irradiated with the excitation light, and as a result, the emission intensity decreases with time (temperature quenching). In some cases, the temperature rise of the wavelength conversion member becomes significant, and the constituent material (glass matrix or the like) may be dissolved.

  Therefore, in order to dissipate heat from the wavelength conversion member, there has been proposed a wavelength conversion element in which a heat dissipation member having a higher thermal conductivity than the wavelength conversion member is provided in the periphery of the wavelength conversion member (for example, a patent) (Ref. 4). In Patent Document 4, as a method of attaching the wavelength conversion member to the heat radiating member made of stainless steel, a notch or a hole is formed in the fitting portion of the heat radiating member having a through hole, and the notch or the hole is filled with a low melting point glass. The method of attachment is mentioned.

JP 2000-208815 A JP 2003-258308 A JP 2007-016171 A JP 2007-323861 A

  However, in the method described in Patent Document 4, a gap is formed between the wavelength conversion member and the heat dissipation member, and heat from the wavelength conversion member is difficult to be transmitted to the heat dissipation member. Moreover, since low melting glass has low thermal conductivity, there is a problem that high heat dissipation cannot be obtained.

  An object of the present invention is to provide a wavelength conversion element manufacturing method, a wavelength conversion element, and a light emitting device that are excellent in heat resistance and that can efficiently transfer heat from the wavelength conversion member to the heat dissipation member.

  The manufacturing method of the present invention includes a heat radiating member having a through hole and made of ceramic, a wavelength converting member arranged in the through hole and made of a ceramic phosphor, and between the wavelength converting member and the through hole. Comprising a ceramic layer, and a method for producing a wavelength conversion element in which the surface of the through hole and the side surface of the wavelength conversion member are bonded by the ceramic layer, comprising a readily sinterable ceramic powder, a binder, A step of preparing a ceramic paste containing a solvent, a step of applying the ceramic paste to at least one of the side surface of the wavelength conversion member and the surface of the through hole, forming a paste coating layer, and a wavelength conversion member in the through hole. The step of placing and heating the paste coating layer to remove the binder and sinter the sinterable ceramic powder to form the ceramic layer It is characterized in that it comprises.

  The through-hole is preferably formed in a tapered shape that expands from one end to the other end. In that case, it is preferable to arrange | position the wavelength conversion member which has a shape corresponding to a through-hole in a through-hole from the other end side.

  The easily sinterable ceramic powder is preferably an easily sinterable alumina powder.

  The ceramic paste may further contain a sintering aid. The content of the sintering aid in the ceramic paste is preferably 15% by weight or less.

  The wavelength conversion member may be made of a polycrystalline ceramic phosphor or a single crystal ceramic phosphor.

  The wavelength conversion member may be a laminate in which ceramic phosphor layers and translucent ceramic layers having higher thermal conductivity than the ceramic phosphor layers are alternately laminated.

  The wavelength conversion element of the present invention has a through-hole and a heat dissipation member made of ceramic, a wavelength conversion member arranged in the through-hole and made of a ceramic phosphor, and the wavelength conversion member and the through-hole. And a ceramic layer provided therebetween, wherein the surface of the through hole and the side surface of the wavelength conversion member are bonded by the ceramic layer.

  The light emitting device of the present invention includes the wavelength conversion element of the present invention and a light source that irradiates the wavelength conversion element with excitation light.

  A laser diode is mentioned as a light source.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in heat resistance and can provide the wavelength conversion element which can transmit the heat | fever from the wavelength conversion member to a thermal radiation member efficiently.

It is typical sectional drawing which shows the wavelength conversion element manufactured with the manufacturing method of the 1st Embodiment of this invention. It is typical sectional drawing for demonstrating the manufacturing method of the 1st Embodiment of this invention. It is typical sectional drawing for demonstrating the manufacturing method of the 2nd Embodiment of this invention. It is typical sectional drawing which shows the wavelength conversion element manufactured with the manufacturing method of the 3rd Embodiment of this invention. It is typical sectional drawing which shows the wavelength conversion member in the 4th Embodiment of this invention. It is typical sectional drawing which shows an example of the light-emitting device using the wavelength conversion element of the 1st Embodiment of this invention.

  Hereinafter, preferred embodiments will be described. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. Moreover, in each drawing, the member which has the substantially the same function may be referred with the same code | symbol.

[Wavelength conversion element]
(First embodiment)
FIG. 1 is a schematic cross-sectional view showing a wavelength conversion element manufactured by the manufacturing method of the first embodiment of the present invention. As shown in FIG. 1, the wavelength conversion element 10 of the present embodiment has a through-hole 3 and is disposed in the heat dissipation member 2 made of ceramic and the through-hole 3, and wavelength conversion made of ceramic phosphor. A member 1 and a ceramic layer 4 provided between the wavelength conversion member 1 and the through hole 3 are provided. The surface 3 a of the through hole 3 and the side surface 1 a of the wavelength conversion member 1 are bonded by the ceramic layer 4. When the wavelength conversion member 1 is irradiated with excitation light, heat is generated from the wavelength conversion member 1 together with fluorescence. Heat generated from the wavelength conversion member 1 is transmitted to the heat dissipation member 2 through the ceramic layer 4.

  Therefore, the wavelength conversion element 10 is excellent in heat dissipation. Moreover, in the wavelength conversion element 10, since the wavelength conversion member 1, the heat radiating member 2, and the ceramic layer 4 which is an adhesive layer are all made of ceramic, the wavelength conversion element 10 is also excellent in heat resistance.

The wavelength conversion member 1 is made of a ceramic phosphor that emits fluorescence by excitation light emitted from a light source. The ceramic phosphor is not particularly limited as long as it emits fluorescence upon incidence of excitation light. Specific examples of the ceramic phosphor include a polycrystalline ceramic phosphor and a single crystal ceramic phosphor. Since these ceramic phosphors are extremely excellent in heat resistance, problems such as dissolution are unlikely to occur even when the output of excitation light is increased to a high temperature. Examples of the polycrystalline ceramic phosphor and the single crystal ceramic phosphor include a garnet ceramic phosphor such as a YAG ceramic phosphor, a nitride ceramic phosphor such as a CASN (CaAlSiN ₃ ) ceramic phosphor, an α-SiAlON phosphor, Alternatively, a nitride oxide ceramic phosphor such as β-SiAlON phosphor may be used. When blue light is used as the excitation light, for example, a ceramic phosphor that emits green light, yellow light, or red light as fluorescence can be used.

  The thickness of the wavelength conversion member 1 is preferably as thin as possible in such a range that the excitation light is surely absorbed by the ceramic phosphor. The reason is that if the wavelength conversion member 1 is too thick, light scattering and absorption in the wavelength conversion member 1 become too large, and the emission efficiency of fluorescence tends to decrease, and the temperature of the wavelength conversion member 1 is low. It becomes high and it becomes easy to generate | occur | produce the fall of the emitted light intensity with time. Therefore, the thickness of the wavelength conversion member 1 is preferably 2 mm or less, more preferably 1 mm or less, and even more preferably 0.8 mm or less. The lower limit of the thickness of the wavelength conversion member 1 is usually about 0.03 mm. For the purpose of obtaining white as the emitted light, the thickness of the wavelength conversion member 1 may be controlled so that the excitation light and the fluorescence are in an appropriate ratio.

  The heat radiating member 2 is provided to radiate heat generated by the wavelength conversion member 1. Therefore, it is preferable that the heat radiating member 2 is formed from a ceramic having a high thermal conductivity. High thermal conductive ceramics include aluminum oxide ceramics, aluminum nitride ceramics, silicon carbide ceramics, boron nitride ceramics, magnesium oxide ceramics, titanium oxide ceramics, niobium oxide ceramics, zinc oxide ceramics, yttrium oxide ceramics A ceramic etc. are mentioned.

  The through hole 3 of the heat radiating member 2 in the present embodiment is formed in a tapered shape that expands from the one end 3b toward the other end 3c. The wavelength conversion member 1 has a shape corresponding to the through hole 3. Specifically, the side surface 1 a of the wavelength conversion member 1 has a shape corresponding to the tapered surface 3 a of the through hole 3. When the side surface 1a of the wavelength conversion member 1 and the surface 3a of the through hole 3 have the above-described shape, the side surface 1a of the wavelength conversion member 1 is replaced with the through hole in the manufacturing process of the wavelength conversion element 10 described later with reference to FIG. It becomes easy to make it press-fit to the surface 3a of 3 uniformly. In the present embodiment, the side surface 1a of the wavelength conversion member 1 and the surface 3a of the through hole 3 are formed in a truncated cone-shaped taper shape. However, the present invention is not limited to this, and for example, formed in a truncated pyramid-shaped taper shape. May be.

  In the wavelength conversion element 10 of the present embodiment, for example, the wavelength conversion member 1 in the through hole 3 is irradiated with excitation light from the one end 3b side, the wavelength conversion member 1 converts the wavelength, and the fluorescence is converted to the other end 3c. The light can be emitted from the side.

  In order to prevent the excitation light and fluorescence from leaking outside from the wavelength conversion member 1, a reflective layer may be provided on the side surface 1 a of the wavelength conversion member 1 and / or the surface 3 a of the through hole 3. Examples of the reflective layer include a ceramic layer containing alumina, titania, or the like. The ceramic layer 4 can also function as a reflective layer.

  A band pass filter may be provided on the excitation light incident side surface of the wavelength conversion member 1 for the purpose of improving the forward extraction of fluorescence. Further, an antireflection film may be provided on the excitation light and fluorescence emission side surface of the wavelength conversion member 1 for the purpose of reducing reflection loss of excitation light and fluorescence.

  Hereinafter, a specific example of a method for manufacturing the wavelength conversion element 10 will be described.

  FIG. 2 is a schematic cross-sectional view for explaining the manufacturing method according to the first embodiment of the present invention. As shown in FIG. 2, a ceramic paste is applied on the side surface 1 a of the wavelength conversion member 1 to form a paste application layer 5. The paste coating layer 5 can be formed as follows.

  A ceramic paste containing an easily sinterable ceramic powder, a binder, and a solvent is prepared. The easily sinterable ceramic powder is a low-temperature sinterable ceramic powder. In the easily sinterable ceramic powder, it is considered that the sintering temperature is lowered by increasing the purity or decreasing the particle size. When the easily sinterable ceramic powder is fired, a dense ceramic can be obtained even when fired at a low temperature of, for example, 1500 ° C. or lower.

  The sintering temperature of the easily sinterable ceramic powder is preferably 1100 to 1550 ° C, and more preferably 1200 to 1400 ° C. By setting the sintering temperature of the easily sinterable ceramic powder within the above range, a denser ceramic can be obtained by firing without significantly increasing the firing temperature.

The average particle diameter (D ₅₀ ) of the easily sinterable ceramic powder is preferably 0.05 to 3 μm, and more preferably 0.08 to 1 μm. By setting the average particle diameter (D ₅₀ ) within the above range, the sintering temperature of the easily sinterable ceramic powder can be made a more preferable range.

  The purity of the easily sinterable ceramic powder is preferably 99% or more, and more preferably 99.99% or more. By setting the purity of the easily sinterable ceramic powder to the above lower limit or more, the sintering temperature of the easily sinterable ceramic powder can be further optimized.

  Examples of the easily sinterable ceramic powder include an easily sinterable alumina powder and an easily sinterable zirconia powder. As the easily sinterable alumina powder, for example, AL-160SG series manufactured by Showa Denko KK, Tymicron TM-D series manufactured by Daimei Chemical Co., Ltd., or the like can be used.

  As the binder, polypropylene carbonate, polybutyl methacrylate, polyvinyl butyral, polymethyl methacrylate, polyethyl methacrylate, ethyl cellulose, nitrocellulose, polyester carbonate and the like can be used, and these can be used alone or in combination.

  As the solvent, terpineol, isoamyl acetate, toluene, methyl ethyl ketone, diethylene glycol monobutyl ether acetate, 2,2,4-trimethyl-1,3-pentadiol monoisobutyrate and the like can be used alone or in combination.

  The ceramic paste can be prepared, for example, by adding and mixing easily sinterable ceramic powder in a solution in which a binder is dissolved in a solvent.

  The ceramic paste may contain a sintering aid. As the sintering aid, for example, magnesium oxide, calcium oxide, zirconia oxide, yttrium oxide, or the like can be used. When a sintering aid is contained, the content is preferably 15% by mass or less with respect to 100% by mass of the ceramic paste.

  In this embodiment, the ceramic paste prepared in this way is applied on the side surface 1a of the wavelength conversion member 1 made of a ceramic phosphor to form the paste application layer 5. Next, the wavelength conversion member 1 in which the paste coating layer 5 is formed on the side surface 1a is disposed on the other end 3c side of the through hole 3 of the heat dissipation member 2 made of ceramic as shown in FIG. Subsequently, the wavelength conversion member 1 is moved in the direction of arrow A, and the paste application layer 5 is heated in a state where the paste application layer 5 formed on the side surface 1a is pressed against the surface 3a of the through hole 3. In addition to removing the binder and solvent, the sinterable ceramic powder is sintered. Thereby, the ceramic layer 4 can be formed, and the surface 3 a of the through hole 3 and the side surface 1 a of the wavelength conversion member 1 can be bonded by the ceramic layer 4. At the time of heating, it is preferable to first remove the binder and solvent at a temperature in the range of 400 to 900 ° C, more preferably 600 to 800 ° C. Then, the dense ceramic layer 4 can be formed by heating at the sintering temperature of the above-described easily sinterable ceramic powder.

  If the temperature for sintering the ceramic powder is too low, pores tend to remain in the ceramic layer 4. When the wavelength conversion member 1 and the heat radiating member 2 are brought into contact with each other and heated in such a state, bubbles tend to be formed in the ceramic layer 4 or a large gap is formed in the process in which the ceramic powders are sintered and contracted. There is. Since these bubbles and gaps have extremely low thermal conductivity, the heat from the wavelength conversion member 1 cannot be effectively transmitted to the heat radiating member 2, and the heat dissipation tends to be reduced.

  In the manufacturing method of this embodiment, since the ceramic layer 4 is formed by heating the paste coating layer 5 composed of the easily sinterable ceramic powder, it is easily baked even when heated at a relatively low temperature. As a result, a dense ceramic layer 4 can be obtained. Therefore, voids are not easily formed in the ceramic layer 4. Moreover, in the manufacturing method of this embodiment, since the wavelength conversion member 1 made of a ceramic phosphor and the heat radiation member 2 made of ceramic are bonded via the ceramic layer 4, the wavelength conversion member 1 and the heat radiation member 2 are bonded. The gap is not easily formed between the wavelength conversion member 1 and the heat radiating member 2. Therefore, in the obtained wavelength conversion element 10, the heat from the wavelength conversion member 1 can be effectively transmitted to the heat radiating member 2 through the ceramic layer 4, and heat dissipation can be improved. In addition, the obtained wavelength conversion element 10 is excellent in heat resistance because the wavelength conversion member 1, the heat dissipation member 2, and the ceramic layer 4 as an adhesive layer are all made of ceramic.

(Second Embodiment)
FIG. 3 is a schematic cross-sectional view for explaining the manufacturing method according to the second embodiment of the present invention. In the present embodiment, the ceramic paste is applied on the surface 3 a of the through hole 3 in the heat radiating member 2, and the paste coating layer 5 is formed on the surface 3 a of the through hole 3. As in the first embodiment, the wavelength conversion member 1 is moved in the direction of arrow A, and the paste coating layer 5 on the surface 3a of the through-hole 3 is pressed against the side surface 1a of the wavelength conversion member 1, and the paste The coating layer 5 is heated to remove the binder and sinter the easily sinterable ceramic powder. Thereby, the ceramic layer 4 which is a sintered body of the paste coating layer 5 can be formed, and the surface 3a of the through hole 3 and the side surface 1a of the wavelength conversion member 1 can be bonded by the ceramic layer 4 (adhesion). (The subsequent drawings are omitted.)

  Also in this embodiment, since the ceramic layer 4 is formed by heating the paste coating layer 5 made of the easily sinterable ceramic powder, it can be easily sintered even when heated at a low temperature. And a dense ceramic layer 4 can be obtained. Therefore, voids are not easily formed in the ceramic layer 4. In addition, since the wavelength conversion member 1 made of a ceramic phosphor and the heat dissipation member 2 made of ceramic are bonded via the ceramic layer 4, the adhesion between the wavelength conversion member 1 and the heat dissipation member 2 is improved. Therefore, it is difficult to form a gap between the wavelength conversion member 1 and the heat dissipation member 2. Therefore, the heat from the wavelength conversion member 1 can be effectively transmitted to the heat radiating member 2 through the ceramic layer 4, and heat dissipation can be improved. The obtained wavelength conversion element is excellent in heat resistance because the wavelength conversion member 1, the heat dissipation member 2, and the ceramic layer 4 as an adhesive layer are all made of ceramic.

  In the present embodiment, the paste coating layer 5 is formed on the entire surface 3 a of the through hole 3, but is not limited to this, and when the wavelength conversion member 1 is pressure-bonded to the surface 3 a of the through hole 3. Alternatively, the paste coating layer 5 may be formed only in the contact area. Further, the paste coating layer 5 may be formed on both the side surface 1 a of the wavelength conversion member 1 and the surface 3 a of the through hole 3.

  Similarly to the wavelength conversion element 10 manufactured in the first embodiment, a band pass filter may be provided on the excitation light incident side surface of the wavelength conversion member 1 for the purpose of improving the forward extraction of fluorescence. Further, an antireflection film may be provided on the excitation light and fluorescence emission side surface of the wavelength conversion member 1 for the purpose of reducing reflection loss of excitation light and fluorescence.

(Third embodiment)
FIG. 4 is a schematic cross-sectional view showing a wavelength conversion element manufactured by the manufacturing method of the third embodiment of the present invention. In the present embodiment, the through hole 3 is formed in a columnar shape. Therefore, the wavelength conversion member 1 is also formed in a cylindrical shape. The through hole 3 in the present invention is not necessarily formed in a tapered shape as in the first and second embodiments, and may have a cylindrical shape as in the present embodiment. Moreover, the shape of the through-hole 3 and the wavelength conversion member 1 may be a prismatic shape.

  Also in this embodiment, since the ceramic layer 4 is formed by heating the paste coating layer 5 made of the easily sinterable ceramic powder, it can be easily sintered even when heated at a low temperature. The dense ceramic layer 4 can be obtained (the drawing before bonding is omitted). Therefore, voids are not easily formed in the ceramic layer 4. In addition, since the wavelength conversion member 1 made of a ceramic phosphor and the heat dissipation member 2 made of ceramic are bonded via the ceramic layer 4, the adhesion between the wavelength conversion member 1 and the heat dissipation member 2 is improved. Therefore, it is difficult to form a gap between the wavelength conversion member 1 and the heat dissipation member 2. Therefore, the heat from the wavelength conversion member 1 can be effectively transmitted to the heat radiating member 2 through the ceramic layer 4, and heat dissipation can be improved. The obtained wavelength conversion element is excellent in heat resistance because the wavelength conversion member 1, the heat dissipation member 2, and the ceramic layer 4 as an adhesive layer are all made of ceramic.

  Similarly to the wavelength conversion element 10 manufactured in the first embodiment, a band pass filter may be provided on the excitation light incident side surface of the wavelength conversion member 1 for the purpose of improving the forward extraction of fluorescence. Further, an antireflection film may be provided on the excitation light and fluorescence emission side surface of the wavelength conversion member 1 for the purpose of reducing reflection loss of excitation light and fluorescence.

(Fourth embodiment)
FIG. 5 is a schematic cross-sectional view showing a wavelength conversion member in the fourth embodiment of the present invention. The wavelength conversion member in the present invention is formed by alternately laminating ceramic phosphor layers 21 and translucent heat radiation layers 22 having a higher thermal conductivity than the ceramic phosphor layer 21 like the wavelength conversion member 20 shown in FIG. You may be comprised from the laminated body made. Specifically, the wavelength conversion member 20 of the present embodiment is formed of a laminate including a ceramic phosphor layer 21 and a light transmissive heat dissipation layer 22 formed on both surfaces thereof. In the present embodiment, the heat generated by irradiating the ceramic phosphor layer 21 with the excitation light is efficiently released to the outside through each light transmissive heat radiation layer 22. Therefore, it can suppress that the temperature of the ceramic fluorescent substance layer 21 rises excessively.

  As the ceramic fluorescent substance layer 21, the thing similar to the wavelength conversion member 1 of 1st Embodiment can be used. Specifically, ceramic phosphors such as polycrystalline ceramic phosphors and single crystal ceramic phosphors can be suitably used.

  The translucent heat dissipation layer 22 has a higher thermal conductivity than the ceramic phosphor layer 21. Specifically, it is preferably 5 W / m · K or more, more preferably 10 W / m · K or more, and further preferably 20 W / m · K or more. Further, the excitation light and the fluorescence emitted from the ceramic phosphor layer 21 are transmitted. Specifically, the total light transmittance at a wavelength of 400 to 800 nm of the translucent heat radiation layer 22 is preferably 10% or more, more preferably 20% or more, and further preferably 30% or more. 40% or more is particularly preferable, and 50% or more is most preferable.

  The translucent heat dissipation layer 22 includes aluminum oxide ceramics, zirconia oxide ceramics, aluminum nitride ceramics, silicon carbide ceramics, boron nitride ceramics, magnesium oxide ceramics, titanium oxide ceramics, niobium oxide ceramics, oxidation Examples thereof include translucent ceramic substrates such as zinc-based ceramics and yttrium oxide-based ceramics.

  The thickness of the light transmissive heat radiation layer 22 is preferably 0.05 to 1 mm, more preferably 0.07 to 0.8 mm, and still more preferably 0.1 to 0.5 mm. When the thickness of the translucent heat radiation layer 22 is too small, the mechanical strength tends to decrease. On the other hand, when the thickness of the translucent heat radiation layer 22 is too large, the wavelength conversion element tends to be enlarged.

  In addition, the thickness of the two translucent heat radiation layers 22 provided on both surfaces of the ceramic phosphor layer 21 may be the same or different. For example, when the mechanical strength as the wavelength conversion member 20 is ensured by relatively increasing the thickness of one light transmissive heat radiation layer 22 (for example, 0.2 mm or more, and further 0.5 mm or more), The thickness of the other light transmissive heat radiation layer 22 may be relatively small (for example, less than 0.2 mm, or even 0.1 mm or less).

  Similar to the wavelength conversion element 10 manufactured in the first embodiment, an antireflection film is formed on the excitation light incident side surface of the translucent heat radiation layer 22 for the purpose of reducing reflection loss of excitation light and improving forward extraction of fluorescence. A band pass filter may be provided. In addition, an antireflection film may be provided on the excitation light and fluorescence emission side surface of the translucent heat radiation layer 22 for the purpose of reducing reflection loss of excitation light and fluorescence. Furthermore, in order to prevent the excitation light and the fluorescence from leaking outside from the ceramic phosphor layer 21 and the translucent heat radiation layer 22, a reflective layer may be provided on the side surface of each layer.

  The wavelength conversion member 20 of this embodiment can be produced as follows, for example.

  A green sheet for the ceramic phosphor layer 21 is prepared by applying a slurry containing a ceramic phosphor and an organic component such as a binder resin or a solvent onto a resin film such as polyethylene terephthalate by a doctor blade method or the like and drying by heating. Is made. The ceramic phosphor layer 21 is obtained by firing the green sheet.

  The wavelength conversion member 20 is obtained by laminating the translucent heat radiation layer 22 on both surfaces of the ceramic phosphor layer 21 and thermocompression bonding. Or you may join the ceramic fluorescent substance layer 21 and the translucent heat-radiating layer 22 through inorganic adhesives, such as a polysilazane. Further, when the ceramic phosphor layer 21 is made of a ceramic phosphor and the translucent heat radiation layer 22 is made of a translucent ceramic, the ceramic phosphor layer 21 and the translucent heat radiation layer 22 are subjected to a discharge plasma sintering method. May be joined together. In this way, the adhesion between the ceramic phosphor layer 21 and the light transmissive heat radiation layer 22 is improved, and the heat generated in the ceramic phosphor layer 21 is easily transferred to the light transmissive heat radiation layer 22.

  The wavelength conversion member 20 of the present embodiment is a three-layer laminate, but is not limited to this. For example, 4 is obtained by alternately laminating ceramic phosphor layers 21 and translucent heat dissipation layers 22. It may be a laminate of more than one layer.

  The wavelength conversion member 20 of this embodiment can be applied to any of the manufacturing methods of the first and second embodiments. Moreover, like the wavelength conversion member 1 of 3rd Embodiment, cylindrical shape and prismatic shape may be sufficient.

  Even when the wavelength conversion member 20 of the present embodiment is used, since the ceramic layer 4 is formed by heating the paste coating layer 5 composed of the easily sinterable ceramic powder, when heated at a low temperature Can be easily sintered, and a dense ceramic layer 4 can be obtained. Therefore, voids are not easily formed in the ceramic layer 4. Moreover, since the wavelength conversion member 20 made of a ceramic phosphor and the heat dissipation member 2 made of ceramic are bonded via the ceramic layer 4, the adhesion between the wavelength conversion member 20 and the heat dissipation member 2 is improved. Therefore, it is difficult for a gap to be formed between the wavelength conversion member 20 and the heat dissipation member 2. Therefore, the heat from the wavelength conversion member 20 can be effectively transmitted to the heat radiating member 2 through the ceramic layer 4, and heat dissipation can be improved. The obtained wavelength conversion element is excellent in heat resistance because the wavelength conversion member 20, the heat radiating member 2, and the ceramic layer 4 as the adhesive layer are all made of ceramic.

[Light emitting device]
(Embodiment of light emitting device)
FIG. 6 is a schematic cross-sectional view showing an example of a light emitting device using the wavelength conversion element according to the first embodiment of the present invention. The light emitting device 30 of the present embodiment is a light emitting device using the wavelength conversion element 10 of the first embodiment. In the light emitting device 30 of the present embodiment, the wavelength conversion element 10 is used as a transmission type wavelength conversion element.

  As shown in FIG. 6, the light emitting device 30 includes a wavelength conversion element 10 and a light source 11. The excitation light 12 emitted from the light source 11 enters the wavelength conversion element 10 from the one end 3b side of the through hole 3. The excitation light 12 incident on the wavelength conversion element 10 is wavelength-converted by the wavelength conversion member 1 into fluorescence 13 having a longer wavelength than the excitation light 12. A part of the excitation light 12 is transmitted through the wavelength conversion element 10. For this reason, the combined light 14 of the excitation light 12 and the fluorescence 13 is emitted from the wavelength conversion element 10. For example, when the excitation light 12 is blue light and the fluorescence 13 is yellow light, white synthetic light 14 can be obtained. The combined light 14 is emitted from the other end 3 c side of the through hole 3.

  In the light emitting device 30, since the ceramic layer 4 is in close contact with the wavelength conversion member 1 and the through hole 3 in the wavelength conversion element 10, the heat from the wavelength conversion member 1 is effectively dissipated through the ceramic layer 4. Can be transmitted. Moreover, since the space | gap part between the wavelength conversion member 1 and the through-hole 3 is reducing, the heat from the wavelength conversion member 1 can be effectively transmitted to the thermal radiation member 2. FIG. Therefore, the heat generated when the wavelength conversion member 1 is irradiated with the excitation light 12 is efficiently released to the outside through the heat dissipation member 2. Therefore, the temperature rise of the wavelength conversion member 1 can be suppressed.

  In the light emitting device 30, the wavelength conversion element 10 is excellent in heat resistance because the wavelength conversion member 1, the heat radiating member 2, and the ceramic layer 4 as the adhesive layer are all made of ceramic. .

  Examples of the light source 11 include an LED and an LD. From the viewpoint of increasing the light emission intensity of the light emitting device 30, the light source 11 is preferably an LD capable of emitting high intensity light.

  In the light emitting device 30 of the present embodiment, the wavelength conversion elements of the second to fourth embodiments may be used instead of the wavelength conversion element 10 of the first embodiment.

DESCRIPTION OF SYMBOLS 1 ... Wavelength conversion member 1a ... Side surface 2 ... Heat radiation member 3 ... Through-hole 3a ... Surface 3b ... One end 3c ... The other end 4 ... Ceramic layer 5 ... Paste application layer 10 ... Wavelength conversion element 11 ... Light source 12 ... Excitation light 13 ... Fluorescence 14 ... synthetic light 20 ... wavelength conversion member 21 ... ceramic phosphor layer 22 ... translucent heat dissipation layer 30 ... light emitting device

Claims (13)

A heat dissipating member having a through hole and made of ceramic, a wavelength converting member arranged in the through hole and made of a ceramic phosphor, and a ceramic provided between the wavelength converting member and the through hole And a method of manufacturing a wavelength conversion element in which a surface of the through hole and a side surface of the wavelength conversion member are bonded by the ceramic layer,
Preparing a ceramic paste containing a readily sinterable ceramic powder, a binder, and a solvent;
Applying the ceramic paste to at least one of the side surface of the wavelength conversion member and the surface of the through hole to form a paste coating layer;
Disposing the wavelength conversion member in the through-hole and heating the paste coating layer to remove the binder and sinter the sinterable ceramic powder to form the ceramic layer; and ,
A method for manufacturing a wavelength conversion element.   The wavelength conversion element manufacturing method according to claim 1, wherein the through-hole is formed in a tapered shape extending from one end to the other end.   The manufacturing method of the wavelength conversion element of Claim 2 which arrange | positions the said wavelength conversion member which has a shape corresponding to the said through-hole in the said through-hole from the said other end side.   The manufacturing method of the wavelength conversion element as described in any one of Claims 1-3 whose said easily sinterable ceramic powder is an easily sinterable alumina powder.   The method for manufacturing a wavelength conversion element according to claim 1, wherein the ceramic paste further contains a sintering aid.   The method for manufacturing a wavelength conversion element according to claim 5, wherein the content of the sintering aid in the ceramic paste is 15% by weight or less.   The manufacturing method of the wavelength conversion element as described in any one of Claims 1-6 in which the said wavelength conversion member consists of a polycrystalline ceramic fluorescent substance or a single crystal ceramic fluorescent substance.   The said wavelength conversion member is a laminated body which laminated | stacked alternately the ceramic fluorescent substance layer and the translucent ceramic layer which has higher thermal conductivity than the said ceramic fluorescent substance layer. The manufacturing method of the wavelength conversion element of description. The manufacturing method of the wavelength conversion element as described in any one of Claims 1-8 whose purity of the said easily sinterable ceramic powder is 99% or more. The manufacturing method of the wavelength conversion element as described in any one of Claims 1-9 whose sintering temperature of the said easily sinterable ceramic powder is 1100-1550 degreeC.   A heat dissipating member having a through hole and made of ceramic, a wavelength converting member arranged in the through hole and made of a ceramic phosphor, and a ceramic provided between the wavelength converting member and the through hole A wavelength conversion element, wherein a surface of the through hole and a side surface of the wavelength conversion member are bonded to each other by the ceramic layer. A light-emitting device comprising: the wavelength conversion element according to claim 11; and a light source that irradiates the wavelength conversion element with excitation light. The light-emitting device according to claim 12 , wherein the light source is a laser diode.

Images