JP2012185980A - Wavelength conversion element, light source including the same and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion element preventing easy peeling of a wavelength conversion member from a heat dissipation member during use as well as achieving weight saving of a light source using the wavelength conversion element, in the wavelength conversion element made by bonding the wavelength conversion member with the heat dissipation member.SOLUTION: The wavelength conversion element is characterized by including the wavelength conversion member made of an inorganic material and the heat dissipation member made of a composite material containing Al and ceramics. The ceramics is preferably any one or more of SiC and AIN.

Description

  The present invention relates to a wavelength conversion element, a light source including the same, and a manufacturing method thereof.

  In recent years, attention has been paid to next-generation light sources such as light sources using light emitting diodes (LEDs) and laser diodes (LDs), such as fluorescent lamps and incandescent lamps. As an example of such a next-generation light source, for example, in Patent Document 1 below, wavelength conversion that absorbs part of light from an LED and emits yellow light on the light emitting side of the LED that emits blue light. A light source having a member disposed thereon is disclosed. This light source emits white light which 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 source tends to be lowered. In particular, when the light from the LED is light having a short wavelength such as blue light and strong energy, such a problem is likely to occur.

  In view of such a problem, for example, Patent Document 2 below proposes a wavelength conversion member in which an inorganic phosphor powder is dispersed in a glass matrix. Since the wavelength conversion member described in Patent Document 2 does not contain a resin and is composed of only an inorganic solid, it has excellent heat resistance and weather resistance. Therefore, by using this wavelength conversion member, it is possible to realize a light source whose luminance is not easily lowered.

  In order to increase the brightness of the light source using the wavelength conversion member, it is necessary to increase the intensity of the excitation light emitted from the light emitting element. However, when a light emitting element that emits high-intensity excitation light is used, there is a problem that it is difficult to obtain desired luminance. This is considered to be caused by thermal quenching due to the rise of the temperature of the wavelength conversion member by converting the light that has not been used for excitation of the phosphor out of the light incident on the wavelength conversion member into heat.

  Therefore, a wavelength conversion element has been proposed in which a heat dissipation member having excellent thermal conductivity such as copper is bonded to the wavelength conversion member. If the said wavelength conversion element is used, the heat | fever of a wavelength conversion member will conduct to a heat radiating member efficiently, and will be thermally radiated from a heat radiating member. For this reason, the temperature rise of a wavelength conversion member can be suppressed and even if it is a case where the intensity | strength of the excitation light from a light emitting element is high, the brightness fall of the light source using the said wavelength conversion member can be suppressed.

JP 2000-208815 A JP 2003-258308 A

  Since the copper heat dissipation member used in the wavelength conversion element is relatively heavy, it is difficult to reduce the weight of the light source using the wavelength conversion element. Therefore, it is conceivable to use a heat radiating member made of aluminum or aluminum alloy as a relatively lightweight material, but the wavelength conversion element formed by joining the heat radiating member to the wavelength converting member has a wavelength converting member in use. There exists a problem that it is easy to peel from a thermal radiation member.

  In view of the above-described problems, the present invention is a wavelength conversion element in which a wavelength conversion member is bonded to a heat dissipation member. The wavelength conversion member reduces the weight of a light source using the wavelength conversion element, and the wavelength conversion member dissipates heat during use. It aims at providing the wavelength conversion element which is hard to peel from a member.

  The present invention relates to a wavelength conversion element having a wavelength conversion member made of an inorganic material and a heat dissipation member made of a composite material containing Al and ceramics.

  As a result of various investigations on the material of the heat dissipation member used in the wavelength conversion element, the present inventor has found that the above problem can be solved by using a heat dissipation member made of a composite material containing Al and ceramics. That is, since the heat radiating member made of a composite material containing Al and ceramics is relatively light, it is easy to reduce the weight of the light source. In addition, in particular, the wavelength conversion member in which the inorganic phosphor powder is dispersed in the glass can be easily brought into a thermal expansion coefficient, so that the wavelength conversion member is not easily peeled even when the temperature becomes high during use.

  Secondly, in the wavelength conversion element of the present invention, the ceramic is preferably SiC or AlN.

  Thirdly, in the wavelength conversion element of the present invention, it is preferable that the heat dissipating member is made of a composite material containing Al 10 to 99.9% by volume and ceramics 0.1 to 90% by volume.

  According to the configuration, the effect can be easily enjoyed.

Fourthly, in the wavelength conversion element of the present invention, it is preferable that the density of the heat radiating member is 3 g / cm ³ or less.

  Fifth, in the wavelength conversion element of the present invention, it is preferable that the heat dissipation member has a thermal conductivity of 100 W / mK or more.

  Sixthly, in the wavelength conversion element of the present invention, the wavelength conversion member is preferably made of a sintered body of a mixed powder containing an inorganic phosphor powder and a glass powder.

  Seventhly, in the wavelength conversion element of the present invention, the glass powder is preferably tin phosphate glass or borosilicate glass.

  Since the tin phosphate glass has a relatively low softening temperature and can lower the firing temperature when producing the wavelength conversion member, thermal degradation of the inorganic phosphor powder can be suppressed. In addition, since borosilicate glass has high heat resistance, it is possible to suppress deterioration due to high-intensity excitation light and heat generation from the inorganic phosphor powder. It also has excellent weather resistance.

  Eighth, the wavelength conversion element of the present invention preferably contains 30 to 99.9% by mass of inorganic phosphor powder.

  According to the said structure, content of the inorganic fluorescent substance powder in the unit volume of a wavelength conversion member can be increased, and it becomes possible to achieve high brightness of the light source using the said wavelength conversion member.

Ninthly, in the wavelength conversion element of the present invention, it is preferable that the difference in coefficient of thermal expansion between the wavelength conversion member and the heat dissipation member is 35 × 10 ⁻⁷ / ° C. or less.

  Tenth, the wavelength conversion element of the present invention preferably includes a reflective layer between the wavelength conversion member and the heat dissipation member.

  As a wavelength conversion element, generally, a “transmission type” that extracts synthetic light of excitation light and fluorescence generated from a phosphor from the side opposite to the excitation light, and a “reflection type” that extracts the synthetic light from the same side as the excitation light. ". In the present invention, a “reflection type” wavelength conversion element can be obtained by providing a reflective layer between the wavelength conversion member and the heat conductive member.

  In particular, when the content of the inorganic phosphor powder in the wavelength conversion member is large, in the “transmission type” wavelength conversion element, the excitation light is scattered inside the wavelength conversion member and hardly transmitted. As a result, it becomes difficult to obtain light having a desired hue. On the other hand, in the case of a “reflection type” wavelength conversion element, light having a desired color is easily obtained even when the content of the inorganic phosphor powder in the wavelength conversion member is large. This is because even if excitation light is scattered in the wavelength conversion member, each scattered light is reflected by the reflective layer and can be efficiently extracted to the excitation light side.

  Eleventh, in the wavelength conversion element of the present invention, the reflective layer is preferably a metal selected from Ag, Al, Au, Pd and Ti or an alloy thereof.

  12thly, it is preferable that the wavelength conversion element of this invention is equipped with the protective layer between the wavelength conversion member and the reflection layer, and / or between the reflection layer and the heat radiating member.

  According to this configuration, it is possible to suppress deterioration due to oxidation of the reflective layer.

Thirteenth, the wavelength conversion element of the present invention, the protective layer is preferably a SiO ₂ or _Al 2 _{O 3.}

  Fourteenth, the present invention relates to a light source comprising any one of the wavelength conversion elements and a light emitting element.

  Fifteenth, the light source of the present invention is preferably for a projector.

It is a typical perspective view explaining Embodiment 1 of the wavelength conversion element of the present invention. It is typical sectional drawing explaining Embodiment 1 of the wavelength conversion element of this invention. It is a typical perspective view explaining Embodiment 2 of the wavelength conversion element of the present invention. It is typical sectional drawing explaining Embodiment 3 of the wavelength conversion element of this invention.

  Hereinafter, embodiments of the wavelength conversion element of the present invention will be described with reference to the drawings. However, the present invention is not limited only to the following embodiments.

<Embodiment 1>
1 and 2 are a schematic perspective view and a schematic cross-sectional view, respectively, for explaining Embodiment 1 of the wavelength conversion element of the present invention.

  As shown in FIGS. 1 and 2, the wavelength conversion element 1 of the present invention is formed by joining a wavelength conversion member 2 on a heat dissipation member 3. In the present embodiment, a reflective layer 4 is formed between the wavelength conversion member 2 and the heat dissipation member 3, and a protective layer 5 is further formed between the wavelength conversion member 2 and the reflection layer 4.

  The wavelength conversion member 2 is a member that transmits part of excitation light emitted from a light emitting element (not shown), absorbs part of the excitation light, and emits fluorescence having a wavelength longer than that of the excitation light.

  The wavelength conversion member 2 is made of an inorganic material. Specifically, it consists of a sintered body of mixed powder containing inorganic phosphor powder and glass powder.

  The inorganic phosphor powder can be appropriately selected according to the wavelength of the excitation light. Specific examples of the inorganic phosphor powder include oxide phosphors, nitride phosphors, oxynitride phosphors, chloride phosphors, acid chloride phosphors, sulfide phosphors, oxysulfide phosphors, and halides. Examples include phosphors, chalcogenide phosphors, aluminate phosphors, halophosphate phosphors, and YAG compound phosphors. These inorganic phosphor powders may be used in combination of two or more.

Specific examples of the inorganic phosphor that emits blue fluorescence (fluorescence having a wavelength of 440 nm to 480 nm) when irradiated with excitation light having a wavelength of 300 to 440 nm include Sr ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , (Sr, Ba) MgAl ₁₀ O ₁₇ : Eu ^{2+ and the} like.

Specific examples of the inorganic phosphor that emits green fluorescence (fluorescence having a wavelength of 500 nm to 540 nm) when irradiated with excitation light having a wavelength of 300 to 440 nm are SrAl ₂ O ₄ : Eu ²⁺ , SrGa ₂ S _4. : Eu ^{2+ and the} like.

Specific examples of inorganic phosphors that emit green fluorescence (fluorescence having a wavelength of 500 nm to 540 nm) when irradiated with blue excitation light having a wavelength of 440 to 480 nm include SrAl ₂ O ₄ : Eu ²⁺ and SrGa ₂ S ₄ : Eu ^2+. Etc.

A specific example of a non-fluorescent material that emits yellow fluorescence (fluorescence having a wavelength of 540 nm to 595 nm) when irradiated with excitation light having a wavelength of 300 to 440 nm is ZnS: Eu ²⁺ .

Specific examples of the inorganic phosphor that emits yellow fluorescence (fluorescence having a wavelength of 540 nm to 595 nm) when irradiated with blue excitation light having a wavelength of 440 to 480 nm include Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ^{2+ and the} like. Can be mentioned.

Specific examples of the inorganic phosphor that emits red fluorescence (fluorescence having a wavelength of 600 nm to 700 nm) when irradiated with excitation light of ultraviolet to near ultraviolet with a wavelength of 300 to 440 nm include Gd ₃ Ga ₄ O ₁₂ : Cr ³⁺ , CaGa _2. S ₄ : Mn ^{2+ and the} like can be mentioned.

Specific examples of inorganic phosphors that emit red fluorescence (fluorescence having a wavelength of 600 nm to 700 nm) when irradiated with blue excitation light having a wavelength of 440 to 480 nm include Mg ₂ TiO ₄ : Mn ⁴⁺ and K ₂ SiF ₆ : Mn ^4+. Etc.

The average particle diameter (D ₅₀ ) of the inorganic phosphor powder is not particularly limited, and is preferably 1 to ₅₀ μm, particularly 5 to 25 μm, for example. If the average particle size (D ₅₀ ) of the inorganic phosphor powder is too large, the emission color tends to be non-uniform. Further, it is difficult to obtain a dense sintered body, and pores easily remain in the wavelength conversion member 2. On the other hand, if the average particle diameter (D ₅₀ ) of the inorganic phosphor powder is too small, the emission intensity tends to decrease.

  The content of the inorganic phosphor powder in the wavelength conversion member 2 is preferably 30 to 99.9% by mass, 35 to 99% by mass, 50 to 95% by mass, and particularly preferably 70 to 90% by mass. When there is too little content of inorganic fluorescent substance powder, there exists a tendency for the brightness | luminance of the light source using the wavelength conversion member 2 to become low. On the other hand, when there is too much content of inorganic fluorescent substance powder, content of glass powder will decrease relatively and it will become difficult to obtain a precise | minute sintered compact. As a result, since the pores increase in the wavelength conversion member 2 and cause light scattering, the light emission intensity of the light source using the wavelength conversion member 2 tends to decrease.

  The glass powder is not particularly limited as long as the inorganic phosphor powder can be suitably dispersed. Specific examples of the glass powder include silicate glass, borosilicate glass, phosphate glass, borophosphate glass, and tin phosphate glass. Especially, since borosilicate glass has high heat resistance, it is possible to suppress deterioration due to high-intensity excitation light and heat generation from inorganic phosphor powder. It also has excellent weather resistance. Further, since tin phosphate glass can be easily softened at a low temperature of, for example, 600 ° C. or lower, wavelength conversion is performed by, for example, heat-pressing a mixture of the inorganic phosphor powder and the glass powder to the heat dissipation member 3. The wavelength conversion member 2 can be easily formed on the element 1. At this time, the heat resistance required for the heat radiating member 3 is reduced, and the degree of freedom in material selection is improved. Moreover, the deterioration of the inorganic phosphor powder at the time of hot pressing can be suppressed.

As a borosilicate glass, the glass composition is expressed in mol%, and the glass powder is in mol percentage, SiO ₂ 30 to 70%, B ₂ O ₃ 1 to 15%, MgO 0 to 10%, CaO 0 to 0. Contains 25%, SrO 0-10%, BaO 5-40%, RO (R represents Mg, Ca, Sr, Ba) 10-45%, Al ₂ O ₃ 0-20%, ZnO 0-10% Those that do are preferred.

The Suzurin salt-based glass, as a glass composition, in _{mol%, SnO 35~80%, P 2 O} 5 5~40%, those containing 2 O 3 0 to 30% _B is preferred.

In addition to the above components, these glasses include, for example, at least one of ZnO, Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O _3, and La ₂ O ₃ as long as the effects of the present invention are not impaired. One component may be contained in a total amount of up to 10 mol%.

  In the present invention, the “softening temperature” is a temperature measured by DTA (differential thermal analysis).

  In addition to the inorganic phosphor powder and the glass powder, the wavelength conversion member 2 may contain a light diffusing material such as alumina powder or silica powder.

  The heat radiating member 3 is made of a composite material containing Al and ceramics. Specifically, Al 10 to 99.9% by volume, ceramics 0.1 to 90% by volume (preferably Al 20 to 99% by volume, ceramics 1 to 80% by volume, more preferably Al 30 to 95% by volume, ceramics 5 to 70% by volume, more preferably Al 40 to 90% by volume, ceramics 10 to 60% by volume, and most preferably Al 50 to 80% by volume, ceramics 20 to 50% by volume). Is preferred. Here, when there is too little content of ceramics, the thermal expansion coefficient of the heat radiating member 3 becomes large, and the wavelength conversion member 2 becomes easy to peel from the heat radiating member 3. On the other hand, when there is too much content of ceramics, the density of the heat radiating member 3 becomes large, and there exists a tendency for the weight reduction of a light source to become difficult. In addition to Al and ceramics, components such as metals such as Mg, Cr, and Fe may be contained in a total amount of 10% by volume or less, particularly 5% by volume or less.

  Examples of ceramics include SiC and AlN. By using these materials, even when a high-power light emitting element such as a laser element is used as an excitation light source, heat is efficiently radiated from the wavelength conversion member 2 to the heat radiating member 3. For this reason, it is difficult for a decrease in luminance due to thermal quenching of the inorganic phosphor powder contained in the wavelength conversion member 2 to occur. Specifically, the heat conductivity of the heat radiating member 3 is preferably 100 W / mK or more, 150 W / mK or more, 200 W / mK or more, particularly 250 W / mK or more.

Moreover, since the heat radiating member 3 consists of the said composite material, weight reduction can be achieved. Specifically, the density of the heat radiating member 3 is preferably 3 g / cm ³ or less, 2.5 g / cm ³ or less, and particularly preferably 2 g / cm ³ or less.

  Furthermore, since the heat radiating member 3 is made of the composite material, it becomes easy to reduce the difference in coefficient of thermal expansion from the wavelength converting member 2. It can suppress peeling from.

The difference in thermal expansion coefficient between the wavelength conversion member 2 and the heat radiating member 3 is 35 × 10 ⁻⁷ / ° C. or less, 30 × 10 ⁻⁷ / ° C. or less, 20 × 10 ⁻⁷ / ° C. or less, particularly 10 × 10 ⁻⁷ / ° C. The following is preferable. If the thermal expansion coefficient difference is too large, for example, when the temperature of the wavelength conversion element 1 rises, the wavelength conversion member 2 is easily peeled off from the heat dissipation member 3.

For example, when the wavelength conversion member 2 is made of a sintered powder of a mixed powder containing tin phosphate glass powder and inorganic phosphor powder, the thermal expansion coefficient of the heat radiating member 3 is 100 × 10 ⁻⁷ to It is preferably 170 × 10 ⁻⁷ / ° C., 120 × 10 ^{−7 to} 160 × 10 ⁻⁷ / ° C., and particularly preferably 130 × 10 ^{−7 to} 150 × 10 ⁻⁷ / ° C. Moreover, when the thing which consists of a sintered compact of the mixed powder containing a borosilicate type | system | group glass powder and inorganic fluorescent substance powder is used as the wavelength conversion member 2, the thermal expansion coefficient of the thermal radiation member 3 is 40 * 10 <^-7>. ˜100 × 10 ⁻⁷ / ° C., 50 × 10 ^{−7 to} 90 × 10 ⁻⁷ / ° C., and particularly preferably 60 × 10 ⁻⁷ to 80 × 10 ⁻⁷ .

  In addition, in this invention, a thermal expansion coefficient says the measured value in the temperature range of 30-380 degreeC.

  The heat radiating member 3 can be produced by, for example, mixing Al powder and ceramic powder at a predetermined ratio and sintering them.

  As shown in FIGS. 1 and 2, in the present embodiment, the heat radiating member 3 is formed in a plate shape. But in this invention, the thermal radiation member 3 is not limited to plate shape, For example, rod shape and a rectangular parallelepiped shape may be sufficient.

  The shape dimension of the wavelength conversion member 2 is not particularly limited. In the present embodiment, specifically, the wavelength conversion member 2 has a disk shape. The diameter of the wavelength conversion member 2 is preferably 100 mm or less, 3 to 80 mm, particularly 25 to 70 mm. If the diameter of the wavelength conversion member 2 is too large, the light source tends to be large and difficult to reduce in weight. Moreover, the thickness of the wavelength conversion member 2 may be 0.01-2 mm, 0.02-1 mm, 0.03-0.5 mm, 0.04-0.2 mm, especially 0.05-0.1 mm. preferable. When the thickness of the wavelength conversion member 2 is too small, the content of the inorganic phosphor powder is reduced and it is difficult to obtain a desired color. Moreover, it becomes difficult to make the thickness of the wavelength conversion member 2 uniform, and it tends to cause color unevenness. On the other hand, when the thickness of the wavelength conversion member 2 is too large, the ratio of the excitation light that is wavelength-converted in the wavelength conversion member 2 becomes large, and it becomes difficult to obtain the synthesized light with a desired hue.

  The reflective layer 4 is preferably made of a material having a reflectance of 85% or more, particularly 90% or more in the wavelength region of 450 to 750 nm. Thereby, the fall of the extraction efficiency of the light from the wavelength conversion element 1 can be suppressed. Specifically, examples of the reflective layer 4 include a metal selected from Ag, Al, Au, Pd, and Ti or an alloy thereof. Among these, Ag or Al having higher thermal conductivity or reflectivity is more preferable.

  The thickness of the reflective layer 4 is preferably 0.01 to 1000 μm, particularly preferably 0.1 to 500 μm. When the thickness of the reflective layer 4 is too small, it becomes difficult to obtain a desired light reflectance. On the other hand, when the thickness of the reflective layer 4 is too large, the film stress tends to increase, or the heat generated in the wavelength conversion member 2 tends not to be conducted to the heat radiating member 3.

The protective layer 5 preferably has a total light transmittance of 80% or more, particularly 90% or more. Thereby, the absorption loss of the light in the protective layer 5 can be reduced, and the fall of the emitted light intensity of a light source can be suppressed. Specifically, examples of the protective layer 5 include SiO ₂ and Al ₂ O ₃ . The thickness of the protective layer 5 is preferably 0.01 to 500 μm, particularly preferably 0.1 to 300 μm. When the thickness of the protective layer 5 is too small, it becomes difficult to obtain the effect of suppressing the oxidation of the reflective layer 4. On the other hand, when the thickness of the protective layer 5 is too large, the film stress tends to increase or the heat generated in the wavelength conversion member 2 tends not to be conducted to the heat radiating member 3.

  Hereinafter, other embodiments and modifications of the wavelength conversion element of the present invention will be described. In the following description, common reference numerals are used for members having substantially the same functions as those of the first embodiment.

<Embodiment 2>
In FIG. 3, the typical perspective view explaining Embodiment 2 of the wavelength conversion element of this invention is shown.

  As shown in FIG. 3, the heat radiating member 3 of the present embodiment has a so-called donut shape in which a circular opening is formed in the center of the disk. Similarly, a donut-shaped wavelength conversion member 2 is joined on the heat dissipation member 3.

  Although not shown in FIG. 3, the reflective layer 4 and further the protective layer 5 may be provided between the wavelength conversion member 2 and the heat radiating member 3 as in the first embodiment.

<Embodiment 3>
FIG. 4 is a schematic cross-sectional view illustrating Embodiment 3 of the wavelength conversion element of the present invention.

  As shown in FIG. 4, the protrusion 6 is formed on the surface of the heat dissipation member 3 in the present embodiment. For this reason, the heat radiating member 3 of the present embodiment has a large surface area and can more effectively promote heat radiating from the heat radiating member 3. As a result, the temperature rise of the wavelength conversion material 2 can be more effectively suppressed.

<Modification>
In Embodiment 1, the case where the sintered body of the mixed powder containing inorganic fluorescent substance powder and glass powder was used as the wavelength conversion member 2 was demonstrated. The present invention is not limited to this configuration, and as the wavelength conversion member 2, for example, a translucent YAG polycrystal or a translucent YAG single crystal may be used.

  The wavelength conversion element of the present invention can be used as a light source for a projector, for example, by combining with a light emitting element such as an LED or an LD.

  Hereinafter, the wavelength conversion element of the present invention will be described in more detail based on examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented without departing from the scope of the present invention. Is possible.

Example 1
(1) Preparation of wavelength conversion element Raw material powder was prepared so as to have a composition of 62% SnO, 22% P ₂ O ₅ , 11% B ₂ O ₃ , ₂ % Al ₂ O ₃ and 3% MgO in mol%. The raw material batch was adjusted. The raw material batch was heated in a crucible at 1000 ° C. for 2 hours. Then, a glass film was produced by roll-forming a part of obtained molten glass. Moreover, the glass block was produced by casting the remaining part of molten glass in a carbon frame.

The obtained glass block was cut into a predetermined size, and the thermal expansion coefficient in a temperature range of 30 to 380 ° C. was measured using a dilatometer. As a result, the coefficient of thermal expansion of the glass was 140 × 10 ⁻⁷ / ° C.

Next, the glass film was pulverized for 15 minutes using a raking machine, and then passed through a 100 μm sieve to obtain glass powder (D ₅₀ : 14 μm, D _max : 145 μm). A YAG phosphor powder was added to the obtained glass powder to prepare a mixed powder. The content of the YAG phosphor powder in the mixed powder was 80% by mass.

Next, a heat radiating member made of a composite material of aluminum and SiC (aluminum 70% by volume, SiC 30% by volume) was cut into a 10 mm square and 1 mm thick plate shape. Next, an Ag reflective layer was formed on the heat radiating member by sputtering to a thickness of 300 nm. Further, an Al ₂ O ₃ protective layer was formed on the Ag reflective layer so as to have a thickness of 200 nm by sputtering.

  The mixed powder was placed on the heat dissipation member on which the reflective layer and the protective layer were formed. A wavelength conversion element having a configuration substantially the same as that of the first embodiment, which is formed by hot press molding at 400 ° C. in a nitrogen atmosphere using a SYS precision glass press apparatus (molding die = glassy carbon flat die). Got. The wavelength conversion member formed on the heat dissipation member had a diameter of 8 mm and a thickness of 0.1 mm.

(2) Evaluation In the obtained wavelength conversion element, a tape test was performed in order to confirm the adhesion of the wavelength conversion member to the heat dissipation member. A test tape (Pharmacel P786, tensile strength: 3.6 kg / cm ² ) was applied to the entire surface of the wavelength conversion member so that it was pressed, pulled in a direction perpendicular to the application surface, and peeled off in 0.1 seconds. The peeling state of the wavelength conversion member was confirmed.

  Further, a laser beam having a wavelength of 2A and a wavelength of 440 nm was irradiated vertically for 10 minutes on the wavelength conversion member side of the wavelength conversion element, and the peeling state of the wavelength conversion member after the light irradiation was confirmed.

  The results are shown in Table 1.

(Comparative Example 1)
A wavelength conversion element was produced and evaluated in the same manner as in the example except that an aluminum alloy (A5052) was used as the heat radiating member. The results are shown in Table 1.

(Comparative Example 2)
A wavelength conversion element was prepared and evaluated in the same manner as in the example except that copper (pure copper) was used as the heat dissipation member. The results are shown in Table 1.

(Example 2)
(1) In Preparation mole% of the wavelength conversion _{element, SiO 2 60%, B 2} O 3 5%, CaO 15%, BaO 10%, Al 2 O 3 5%, the raw material powder so as to have the composition of 5% ZnO The raw material batch was adjusted. The raw material batch was heated in a crucible at 1400 ° C. for 2 hours. Then, a glass film was produced by roll-forming a part of obtained molten glass. Moreover, the glass block was produced by casting the remaining part of molten glass in a carbon frame.

The obtained glass block was cut into a predetermined size, and the thermal expansion coefficient in a temperature range of 30 to 380 ° C. was measured using a dilatometer. As a result, the thermal expansion coefficient of the glass was 70 × 10 ⁻⁷ / ° C.

Next, the glass film was pulverized for 30 minutes using a roughing machine, and then passed through a 100 μm sieve to obtain glass powder (D ₅₀ : 15 μm, D _max : 132 μm). A YAG phosphor powder was added to the obtained glass powder to prepare a mixed powder. The content of the YAG phosphor powder in the mixed powder was 80% by mass.

  Next, the mixed powder was pressure-molded using a mold to produce a button-shaped preform having a diameter of 1 cm. This preform was fired in a vacuum atmosphere at a firing temperature of 830 ° C. and then processed to obtain a disk-shaped wavelength conversion member having a diameter of 8 mm and a thickness of 0.1 mm.

On the obtained wavelength conversion member, an Ag reflective layer was formed by sputtering to a thickness of 300 nm. Next, an Al ₂ O ₃ protective film was formed on the Ag film so as to have a thickness of 200 nm by a sputtering method. Further, a Cr film and an Au film were formed on the Al ₂ O ₃ protective film so as to be 100 nm each by sputtering.

  Next, a heat radiating member made of a composite material of aluminum and SiC (aluminum 30% by volume, SiC 70% by volume) was cut into a plate shape having a 10 mm square and a thickness of 1 mm. An Au film was formed on the heat radiating member so as to have a thickness of 100 nm by a sputtering method.

  Gold-tin solder was placed on the surface of the heat dissipation member on which the Au film was formed, and the wavelength conversion member was further placed thereon so that the film-formed surface was on the lower side. In this state, heating was performed on a heat block heated to 200 ° C. to soften the gold-tin solder, and the wavelength conversion member and the heat dissipation member were joined to obtain a wavelength conversion element.

  The obtained wavelength conversion element was evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 3)
A wavelength conversion element was produced and evaluated in the same manner as in Example 2 except that an aluminum alloy (A5052) was used as the heat radiating member. The results are shown in Table 2.

(Comparative Example 4)
A wavelength conversion element was produced and evaluated in the same manner as in Example 2 except that copper (pure copper) was used as the heat radiating member. The results are shown in Table 2.

  As shown in Tables 1 and 2, the wavelength conversion elements of Examples 1 and 2 did not peel off the wavelength conversion member in both the tape test and the light irradiation test.

  On the other hand, in Comparative Examples 1 and 3 using an aluminum alloy as the heat dissipation member, the wavelength conversion member was peeled off in the tape test. In the light irradiation test, the wavelength conversion member was peeled off 3 minutes and 1 minute after laser light irradiation, respectively. Further, in Comparative Examples 2 and 4 using copper as the heat radiating member, the wavelength conversion member was not peeled off in the tape test, but in the light irradiation test, the wavelength conversion member was 7 minutes and 5 minutes after laser light irradiation, respectively. Peeling occurred.

1 Wavelength Conversion Element 2 Wavelength Conversion Member 3 Heat Dissipation Member 4 Reflective Layer 5 Protective Layer 6 Projection

Claims (15)

  A wavelength conversion element comprising: a wavelength conversion member made of an inorganic material; and a heat dissipation member made of a composite material containing Al and ceramics.   The wavelength conversion element according to claim 1, wherein the ceramic is SiC or AlN.   3. The wavelength conversion element according to claim 1, wherein the heat dissipating member is made of a composite material containing Al 10 to 99.9% by volume and ceramics 0.1 to 90% by volume. The wavelength conversion element according to claim 1, wherein the density of the heat dissipating member is 3 g / cm ³ or less.   The wavelength conversion element according to claim 1, wherein the heat dissipation member has a thermal conductivity of 100 W / mK or more.   The wavelength conversion element according to any one of claims 1 to 5, wherein the wavelength conversion member is made of a sintered body of a mixed powder containing an inorganic phosphor powder and a glass powder.   The wavelength conversion element according to claim 6, wherein the glass powder is tin phosphate glass or borosilicate glass.   The wavelength conversion element according to claim 6 or 7, comprising 30 to 99.9% by mass of inorganic phosphor powder. The wavelength conversion element according to claim 1, wherein a difference in thermal expansion coefficient between the wavelength conversion member and the heat dissipation member is 35 × 10 ⁻⁷ / ° C. or less.   The wavelength conversion element according to claim 1, further comprising a reflective layer between the wavelength conversion member and the heat dissipation member.   The wavelength conversion element according to claim 10, wherein the reflective layer is a metal selected from Ag, Al, Au, Pd, and Ti, or an alloy thereof.   The wavelength conversion element according to claim 10 or 11, further comprising a protective layer between the wavelength conversion member and the reflection layer and / or between the reflection layer and the heat dissipation member. The wavelength conversion element according to claim 12, wherein the protective layer is made of SiO ₂ or Al ₂ O ₃ .   A light source comprising the wavelength conversion element according to claim 1 and a light emitting element.   The light source according to claim 14, wherein the light source is used for a projector.