JP5724461B2 - Method for manufacturing wavelength conversion member, wavelength conversion member produced thereby, and wavelength conversion element - Google Patents

Description

  The present invention relates to a method for manufacturing a wavelength conversion member, a wavelength conversion member produced thereby, and a wavelength conversion element using the wavelength conversion member.

  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, a wavelength conversion member 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 in which is arranged 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 in which the inorganic phosphor powder is dispersed in the resin matrix 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 the above problem, for example, Patent Document 2 below proposes a wavelength conversion member in which inorganic phosphor powder is dispersed in glass. 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.

JP 2000-208815 A JP 2003-258308 A

  In order to increase the brightness of the light source using the wavelength conversion member in which the inorganic phosphor powder is dispersed in the glass, it is only necessary to increase the intensity of the excitation light. Thus, the hue of the transmitted excitation light becomes strong and it is difficult to obtain desired white light. For this reason, it is necessary to increase the intensity of the excitation light and at the same time increase the content of the inorganic phosphor powder in the wavelength conversion member to increase the fluorescence intensity.

  However, when the content of the inorganic phosphor powder in the wavelength conversion member is increased, it becomes difficult to obtain a dense sintered body, and pores are easily generated in the wavelength conversion member. If there are many pores in the wavelength conversion member, light is likely to be scattered, and the emission intensity is likely to be reduced.

  This invention is made | formed in view of the above point, The objective is to attain high brightness of the light source using the wavelength conversion member which disperse | distributed inorganic fluorescent substance powder in glass.

The present invention includes (1) a step of firing a mixed powder containing an inorganic phosphor powder and a glass powder in an atmosphere of less than 1.013 × 10 ⁵ Pa, and (2) a temperature at which the softening point of the glass powder is ± 150 ° C. In the range, the mixed powder is pressed using a molding die to obtain a sintered body, (3) pressed under an atmosphere of 1.013 × 10 ⁵ Pa or more and / or using a molding die. The present invention also relates to a method for producing a wavelength conversion member, comprising a step of cooling a sintered body.

  Below, the effect obtained by each process in the manufacturing method of this invention is demonstrated.

First, in the step (1), the mixed powder containing the inorganic phosphor powder and the glass powder is baked in an atmosphere lower than 1.013 × 10 ⁵ Pa (1 atm) to thereby obtain the inorganic phosphor powder and the glass powder. The gas existing between the particles can be effectively discharged, and the generation of pores in the wavelength conversion member can be suppressed.

  Next, in the step (2), the mixed powder is pressed using a mold in a temperature range of glass powder softening point ± 150 ° C. (glass powder softening point−150 ° C. to glass powder softening point + 150 ° C.). As a result, the inorganic phosphor powder and the glass powder are pressed against each other, and at the same time, the softened and fluidized glass powder serves as a binder to obtain a dense sintered body.

Furthermore, in the step (3), air bubbles trapped inside the sintered body are cooled while being pressurized in an atmosphere of 1.013 × 10 ⁵ Pa or more and / or while being pressed using a mold. It is possible to suppress expansion and generation of new pores.

  As described above, according to the production method of the present invention, in the wavelength conversion member including the inorganic phosphor powder and the glass powder, the material is densely sintered and solidified even when the content of the inorganic phosphor powder in the member is large. The ratio of the inorganic phosphor powder present per unit volume can be increased. As a result, it is possible to achieve high brightness of the light source using the wavelength conversion member.

2ndly, it is preferable that the manufacturing method of the wavelength conversion member of this invention performs a press by the pressure of 2 * 10 < ⁶ > Pa or more in process (2) or (3).

  Thirdly, it is preferable that the manufacturing method of the wavelength conversion member of this invention performs cooling in an inert atmosphere in a process (3).

  According to the said structure, it can suppress that an inorganic fluorescent substance powder and glass powder change a property by oxidation. Specifically, it can suppress that the fluorescence intensity of inorganic fluorescent substance powder falls or discoloration of glass powder.

  Fourthly, in the method for producing a wavelength conversion member of the present invention, the softening point of the glass powder is preferably 900 ° C. or lower.

  According to the said structure, it becomes possible to suppress deterioration of inorganic fluorescent substance powder at the time of sintering.

  Fifth, in the method for producing a wavelength conversion member of the present invention, the inorganic phosphor powder comprises an oxide phosphor, a nitride phosphor, an oxynitride phosphor, a chloride phosphor, an acid chloride phosphor, and a sulfide. Preferably, the phosphor comprises at least one selected from phosphors, oxysulfide phosphors, halide phosphors, chalcogenide phosphors, aluminate phosphors, halophosphate phosphors, and YAG compound phosphors.

Sixth, in the method for producing a wavelength conversion member of the present invention, the average particle diameter D50 of the inorganic phosphor powder is preferably ₅₀ μm or less.

  According to the said structure, the clearance gap between each particle | grains of inorganic fluorescent substance powder can be made small, and a precise | minute wavelength conversion member with few pores can be obtained.

  Seventh, the present invention relates to a wavelength conversion member manufactured by any one of the above-described manufacturing methods.

  Eighth, the wavelength conversion member 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.

  Ninth, the wavelength conversion member of the present invention preferably has a porosity of 35% or less.

  According to the said structure, scattering of the light in the wavelength conversion member is suppressed, and it becomes possible to achieve high brightness of the light source using the said wavelength conversion member.

Tenth, the present invention is formed of a sintered body of powder mixture of glass powder and the average particle diameter D ₅₀ containing an inorganic phosphor powder is 50μm or less, the content of the inorganic phosphor powder is 30 to 99.9 It is related with the wavelength conversion member characterized by being the mass%.

  Eleventhly, the present invention relates to a wavelength conversion element characterized in that any one of the wavelength conversion members is bonded to a heat conductive member.

  The wavelength converting member generates heat when irradiated with excitation light, and tends to decrease in luminance. This is considered to be caused by temperature quenching of the inorganic phosphor powder. In particular, when the intensity of the excitation light is high, the degree of luminance reduction increases. Then, if it is a wavelength conversion element formed by joining a wavelength conversion member to a heat conductive member, the heat generated in the wavelength conversion member is efficiently conducted to the heat conductive member and radiated. For this reason, the temperature rise of the wavelength conversion member can be suppressed, and the brightness | luminance fall accompanying the temperature rise of a wavelength conversion member can be suppressed.

  12thly, it is preferable that the wavelength conversion element of this invention has a reflection layer between a wavelength conversion member and a heat conductive 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.

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

  14thly, it is preferable that the light source of this invention is for projectors.

It is a typical perspective view explaining Embodiment 1 of the manufacturing method of this invention. It is a typical perspective view explaining Embodiment 2 of the manufacturing method of this invention. It is a typical perspective view of the wavelength conversion element of the present invention.

  Hereinafter, embodiments of the manufacturing method 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>
In FIG. 1, the typical perspective view explaining Embodiment 1 of the manufacturing method of this invention is shown.

  First, in the step (1), the mixed powder 2 containing the inorganic phosphor powder and the glass powder is put into a mold 1 composed of an upper punch 1a, a die 1b, and a lower punch 1c, and is fired.

The pressure in the atmosphere in the step (1) is preferably less than 1.013 × 10 ⁵ Pa, 1 × 10 ⁴ Pa or less, 1 × 10 ² Pa or less, particularly 1 Pa or less. When the pressure is too large, pores are generated in the wavelength conversion member and light is easily scattered, and the light emission intensity of the light source using the wavelength conversion member tends to decrease.

  In the present embodiment, the mixed powder 2 is not molded but fired as it is. However, the mixed powder 2 may be fired after being pressed using the upper punch 1a to form a preform. Alternatively, firing may be performed while the mixed powder 2 is pressed by the upper punch 1a.

  Next, in step (2), the sintered powder 3 is obtained by further firing while pressing the mixed powder 2 with the upper punch 1a near the softening point of the glass powder.

  In step (2), the temperature at which the mixed powder 2 is pressed is as follows: glass powder softening point ± 150 ° C., glass powder softening point ± 120 ° C., glass powder softening point ± 100 ° C., glass powder softening point ± It is preferable to be within the range of 80 ° C., particularly the softening point of glass powder ± 50 ° C. When the press temperature is higher than the above range, the glass powder is altered, and as a result, the light emission intensity of the light source using the obtained wavelength conversion member tends to decrease. On the other hand, when the pressing temperature of the mixed powder 2 is lower than the above range, the glass powder is difficult to soften and flow, and it becomes difficult to obtain a dense sintered body 3. As a result, the pores in the obtained wavelength conversion member are increased, and the mechanical strength tends to decrease, or the light emission intensity of the light source using the wavelength conversion member tends to decrease.

  In addition, although the temperature at the time of pressing the mixed powder 2 is decided according to the softening point of glass powder as above-mentioned, specifically, it is preferable to satisfy | fill the range of 300-1000 degreeC, especially 300-900 degreeC. The pressing temperature is preferably matched with the maximum firing temperature of the mixed powder 2.

The pressing pressure is preferably 2 × 10 ⁶ Pa or more, 5 × 10 ⁶ Pa or more, 1 × 10 ⁷ Pa or more, particularly 2 × 10 ⁷ Pa or more. If the pressure is too small, pores are likely to be generated inside the wavelength conversion member. In addition, although it does not specifically limit about an upper limit, Actually, it is 1 * 10 <10 ^> or less, Especially 1 * 10 < ⁹ > or less.

  The pressing time is not particularly limited as long as the mixed powder 2 is sufficiently sintered. For example, the pressing time is appropriately selected from 0.1 to 5 hours, particularly 0.5 to 2 hours.

  Examples of the material of the mold 1 include graphite, tungsten, and ceramic. If a release powder such as BN is applied to the surface of the mold, the fusion of the sintered body to the mold can be suppressed.

  In addition, the atmosphere in the step (2) is not particularly limited, but from the viewpoint of suppressing the oxidation of the glass powder and the inorganic phosphor powder, the atmosphere is reduced in the same manner as in the step (1), or the step (3) described later. It is preferable to make it an inert atmosphere like.

Furthermore, in the step (3), the sintered compact 3 is cooled while being pressurized in an atmosphere of 1.013 × 10 ⁵ Pa or more, and the wavelength conversion member 4 is obtained.

The pressure in the atmosphere in the step (3) is preferably 1.013 × 10 ⁵ Pa or more, 2 × 10 ⁵ Pa or more, 5 × 10 ⁵ Pa or more, particularly 1 × 10 ⁶ Pa or more. When the pressure is too small, bubbles trapped inside the sintered body 3 tend to expand or new pores are generated. The upper limit is not particularly limited, but is practically 1 × 10 ⁷ or less, particularly 5 × 10 ⁶ or less.

  Note that the cooling atmosphere is preferably an inert atmosphere such as nitrogen or a rare gas element such as argon or neon. By making the atmosphere during cooling into an inert atmosphere, it is possible to suppress the property change of the inorganic phosphor powder and the glass powder due to oxidation. Specifically, it can suppress that the fluorescence intensity of inorganic fluorescent substance powder falls or discoloration of glass powder.

  Examples of the inorganic phosphor powder include oxide phosphor, nitride phosphor, oxynitride phosphor, chloride phosphor, acid chloride phosphor, sulfide phosphor, oxysulfide phosphor, and halide fluorescence. Body, chalcogenide phosphor, aluminate phosphor, halophosphate phosphor, and YAG compound phosphor.

Specific examples of inorganic phosphors that emit blue fluorescence (fluorescence having a wavelength of 440 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 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 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 to 595 nm) when irradiated with excitation light of ultraviolet to near ultraviolet with a wavelength of 300 to 440 nm includes ZnS: Eu ^{2+ and the} like.

Specific examples of inorganic phosphors that emit yellow fluorescence (fluorescence with a wavelength of 540 to 595 nm) when irradiated with blue excitation light with 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 inorganic phosphors that emit red fluorescence (fluorescence having a wavelength of 600 to 700 nm) when irradiated with ultraviolet to near ultraviolet excitation light having a wavelength of 300 to 440 nm include Gd ₃ Ga ₄ O ₁₂ : Cr ³⁺ and 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 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.

  A plurality of inorganic phosphor powders may be mixed and used in accordance with the wavelength range of the excitation light and the color to be emitted. For example, when it is desired to obtain white light by irradiating ultraviolet excitation light, inorganic phosphor powders that emit blue, green, and red (further yellow) fluorescence may be mixed and used.

The average particle diameter D50 of the inorganic phosphor powder is preferably ₅₀ μm or less, particularly preferably 25 μm or less. When the average particle diameter D ₅₀ of the inorganic phosphor powder is too large, dense sintered body is difficult to obtain. In addition, the emission color may be non-uniform. On the other hand, when the average particle diameter D ₅₀ of the inorganic phosphor powder is too small, the emission intensity decreases. Therefore, the average particle diameter D ₅₀ of the inorganic phosphor powder 1μm or more, and particularly preferably 5μm or more.

  The content of the inorganic phosphor powder in the wavelength conversion member 4 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 4 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.

  The glass powder used in the production method of the present invention has a role as a binder that binds the inorganic phosphor powder to each other and a role as a medium for stably holding the inorganic phosphor powder. In addition, since the color tone of the wavelength conversion member varies depending on the composition system of the glass used, and the reactivity with the inorganic phosphor powder varies, it is necessary to select the glass composition to be used in consideration of various conditions. .

  The glass powder is preferably made of glass having a softening point of 900 ° C. or lower, particularly 850 ° C. or lower. When the softening point of the glass is increased, the firing temperature is also increased, so that the inorganic phosphor powder is deteriorated and it is difficult to obtain a wavelength conversion member having high luminous efficiency.

Specific examples of the glass powder include SiO ₂ —B ₂ O ₃ —RO (R represents one or more of Mg, Ca, Sr, and Ba) -based glass, SiO ₂ —B ₂ O ₃ —R ′ _2. O (R ′ represents one or more of Li, Na, and K) glass, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ glass, SiO ₂ —B ₂ O ₃ —ZnO glass, ZnO -B ₂ O ₃ based glass, _SnO-P 2 _{O 5} based glass. When firing at a low temperature, ZnO—B ₂ O ₃ glass or SnO—P ₂ O ₅ glass capable of lowering the softening point can be selected relatively easily, and the weather resistance of the wavelength conversion member is improved. When it is desired to make it, SiO ₂ —B ₂ O ₃ —RO glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O glass, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ glass or SiO ₂ — A B ₂ O ₃ —ZnO-based glass may be selected.

When SiO ₂ —B ₂ O ₃ —RO-based glass is used as the glass powder, in mol%, SiO ₂ 30 to 80%, B ₂ O ₃ 1 to 30%, MgO 0 to 10%, CaO 0 to 30%, It is preferable to use one containing SrO 0 to 20%, BaO 0 to 40%, RO 5 to 45%, Al ₂ O ₃ 0 to 10%, ZnO 0 to 10%.

When SiO ₂ —B ₂ O ₃ —R ′ ₂ O glass is used as the glass powder, it is mol%, SiO ₂ 30 to 80%, B ₂ O _{3 1 to} 55%, Li ₂ O 0 to 20%, Na _{2 O 0~25%, K 2 O} 0~25%, R 2 O 5~35%, Al 2 O 3 0~10%, it is preferable to use those containing 0% ZnO.

When SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ glass is used as the glass powder, it is mol%, SiO ₂ 30 to 70%, B ₂ O ₃ 15 to 55%, Al ₂ O ₃ 15 to 55%, _{li 2 O 0~10%, Na 2} O 0~10%, K 2 O 0~10%, 0~10% MgO, CaO 0~10%, SrO 0~10%, containing 0% BaO It is preferable to use one.

When SiO ₂ —B ₂ O ₃ —ZnO-based glass is used as the glass powder, the molar percentage is SiO ₂ 5-50%, B ₂ O ₃ 15-55%, ZnO 30-80%, Li ₂ O 0-10. %, Na ₂ O 0-10%, K ₂ O 0-10%, MgO 0-10%, CaO 0-10%, SrO 0-10%, BaO 0-10% preferable.

When using a _ZnO-B 2 _{O 3} based glass as the glass powder, in _{mol%, 30~80% ZnO, B 2} O 3 20~70%, SiO 2 0~5%, Li 2 O 0~10%, Na _{2 O 0~10%, K 2 O} 0~10%, 0~10% MgO, CaO 0~10%, SrO 0~10%, it is preferable to use those containing 0% BaO.

When using a _SnO-P 2 _{O 5} based glass as the glass powder, in _{mol%, SnO 35~80%, P 2} O 5 5~40%, B 2 O 3 0~30%, Al 2 O 3 0~10 _{%, SiO 2 0~10%, Li} 2 O 0~10%, Na 2 O 0~10%, K 2 O 0~10%, 0~10% MgO, CaO 0~10%, SrO 0~10% It is preferable to use those containing 0 to 10% of BaO.

  The mixed powder 2 (or wavelength conversion member 4) may contain a light diffusing material such as alumina powder or silica powder in addition to the inorganic phosphor powder and the glass powder.

<Embodiment 2>
In the present embodiment, steps (1) and (2) are the same as in the first embodiment, and only step (3) is different. Specifically, in the present embodiment, in the step (3), the wavelength conversion member 4 is manufactured by performing cooling while pressing the sintered body 3 using the mold 1.

The pressing pressure in the step (3) is preferably 2 × 10 ⁶ Pa or more, 5 × 10 ⁶ Pa or more, 1 × 10 ⁷ Pa or more, particularly 2 × 10 ⁷ Pa or more. When the pressure is too small, bubbles trapped inside the sintered body 3 tend to expand or new pores are generated. In addition, although it does not specifically limit about an upper limit, Actually, it is 1 * 10 < ¹⁰ > Pa or less, Especially 1 * 10 < ⁹ > Pa or less.

In step (3), as in the first embodiment, the atmospheric pressure may be 1.013 × 10 ⁵ Pa or more.

  The porosity of the wavelength conversion member 4 is preferably 35%, 20%, 10% or less, 5% or less, and particularly preferably 2% or less. If the porosity is too high, the amount of inorganic phosphor powder present per unit volume of the wavelength conversion member 4 is reduced, and light is easily scattered in the wavelength conversion member 4, so that the light source using the wavelength conversion member 4 There is a tendency for the emission intensity to decrease. Moreover, there exists a tendency for the mechanical strength of the wavelength conversion member 4 to fall.

  The wavelength conversion member 4 may be subjected to post-processing such as polishing and cutting.

  Although the wavelength conversion member 4 can be used as it is, as shown in FIG. 3, it may be used as a wavelength conversion element 6 formed by bonding a heat conductive member 5 to the wavelength conversion member 4. Thereby, as described above, since the heat generated in the wavelength conversion member 4 is efficiently conducted to the heat conductive member 5 and radiated, the temperature increase of the wavelength conversion member 4 can be suppressed, and the wavelength conversion is performed. It is possible to suppress a decrease in luminance due to the temperature increase of the member 4.

  The material of the heat conductive member 5 is a metal such as Cu or Al, an alloy containing one or more of them, or a composite of another substance (for example, a composite formed by mixing and sintering Al and SiC). Body etc.).

  Further, by providing a reflective layer (not shown) between the wavelength conversion member 4 and the heat conductive member 5, a reflective wavelength conversion element can be obtained.

  Examples of the reflective layer include metals such as Ag, Al, Au, Pd, and Ti, or alloys containing one or more of them.

  The wavelength conversion element 6 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.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.

  Tables 1-10 show Examples 1-12 of the present invention and Comparative Examples 1-12.

(A) Production of Glass Powder First, each raw material powder was weighed and mixed so as to have the composition shown in the table to prepare a raw material batch. The raw material batch was put into a platinum crucible, melted at 900 to 1400 ° C. for 1 hour to be vitrified, and then formed into a film. The glass film was pulverized with a ball mill and then passed through a 165 mesh sieve to obtain a glass powder having an average particle size of 45 μm.

  The softening point was measured about the obtained glass powder. The softening point of the glass powder was measured using a macro type differential thermal analyzer, and evaluated based on the value of the fourth inflection point of the obtained graph.

(B) Production of Wavelength Conversion Member The inorganic phosphor powder was mixed with the glass powder obtained as described above so as to have a blending ratio shown in the table. The obtained mixed powder was put into a mold as shown in FIG. 1 and press-molded to prepare a preform. Thereafter, firing was performed under the conditions shown in the table.

  First, in step (1), firing (temperature increase) was performed in the atmosphere shown in the table until the firing temperature was reached.

  Next, in step (2), pressing was performed using a mold at the firing temperature and pressing pressure described in the table. The comparative example was not pressed. In step (2), the atmosphere of step (1) was maintained.

  Furthermore, in the step (3), cooling was performed in the atmosphere described in the table. In some examples, pressing was performed using a mold at the pressing pressure described in the table.

  As described above, a disk-shaped sintered body (wavelength conversion member) having a diameter of 20 mm and a thickness of 1 mm was obtained.

(C) Characteristic Evaluation of Wavelength Conversion Member The porosity and luminescence intensity of the obtained sintered body were measured. The results are shown in the table.

  The porosity is determined by measuring the bulk density of the sintered body using the Archimedes method, then pulverizing the fired body and measuring the true density of the fired body with an ultra pycnometer. (1-bulk density / true density) It calculated | required by the type | formula of x100 (%).

  The emission intensity was measured as follows. First, a wavelength conversion member was fixed to a Cu plate surface cut into a square having a thickness of 0.6 mm and an outer shape of 25 mm using high thermal conductive grease, and a wavelength conversion element as shown in FIG. 3 was produced. Next, a laser beam having an electric current of 2A and an excitation wavelength of 440 nm was vertically incident on the wavelength conversion member side of the wavelength conversion element, the excitation light contained in the reflected light was removed by the dichroic mirror, and the light intensity was attenuated by the ND filter. Thereafter, the obtained fluorescence peak intensity was measured. In each table, the emission intensity is shown as a relative value with respect to the emission intensity, with the emission intensity of the example having the smallest fluorescence peak intensity being 100 (%).

  As is apparent from the table, it can be seen that the wavelength conversion members produced by the production methods of Examples 1 to 12 have a porosity of as small as 9% or less and good emission intensity.

On the other hand, in Comparative Examples 1, 3, and 5 to 12, firing was performed in an atmosphere of 1.013 × 10 ⁵ Pa or higher in the step (1), and no press molding was performed in the step (2). In Comparative Examples 2 and 4, press molding was not performed in step (2), and cooling was performed in an atmosphere lower than 1.013 × 10 ⁵ Pa (no press molding) in step (3). Therefore, the wavelength conversion member produced by the manufacturing method of Comparative Examples 1 to 12 has a porosity as high as 38% or more and is inferior in light emission intensity.

DESCRIPTION OF SYMBOLS 1 Mold 1a Upper punch 1b Dies 1c Lower punch 2 Mixed powder 3 Sintered body 4 Wavelength conversion member 5 Thermally conductive member 6 Wavelength conversion element P Pressure direction

Claims (14)

(1) A step of firing a mixed powder containing an inorganic phosphor powder and a glass powder in a pressed state using a mold in an atmosphere of less than 1.013 × 10 ⁵ Pa, and (2) a softening point of the glass powder. in a temperature range of ± 0.99 ° C., while the mixed powder using a mold and pressed, further baked to obtain a sintered body, to cool the sintered body while pressing with (3) forming the shape type A process for producing a wavelength conversion member, comprising: a step. 2. The method for producing a wavelength conversion member according to claim 1, wherein in the step (2) or (3), pressing is performed at a pressure of 2 × 10 ⁶ Pa or more.   The method for manufacturing a wavelength conversion member according to claim 1 or 2, wherein in step (3), cooling is performed in an inert atmosphere.   The softening point of glass powder is 900 degrees C or less, The manufacturing method of the wavelength conversion member in any one of Claims 1-3 characterized by the above-mentioned.   Inorganic phosphor powder is oxide phosphor, nitride phosphor, oxynitride phosphor, chloride phosphor, acid chloride phosphor, sulfide phosphor, oxysulfide phosphor, halide phosphor, chalcogen The wavelength conversion member according to any one of claims 1 to 4, wherein the wavelength conversion member comprises at least one selected from a fluoride phosphor, an aluminate phosphor, a halophosphate phosphor, and a YAG compound phosphor. Manufacturing method. Method for manufacturing a wavelength conversion member according to claim 1, wherein an average particle diameter D ₅₀ of the inorganic phosphor powder is characterized in that it is 50μm or less.   A wavelength conversion member produced by the production method according to claim 1.   The wavelength conversion member according to claim 7, comprising 30 to 99.9% by mass of inorganic phosphor powder.   The wavelength conversion member according to claim 7 or 8, wherein the porosity is 35% or less. It consists of a sintered body of a mixed powder containing glass powder and an inorganic phosphor powder having an average particle diameter D50 of ₅₀ μm or less, and the content of the inorganic phosphor powder is 30 to 99.9% by mass Wavelength conversion member to be used.   A wavelength conversion element obtained by bonding the wavelength conversion member according to claim 7 to a heat conductive member.   The wavelength conversion element according to claim 11, further comprising a reflective layer between the wavelength conversion member and the heat conductive member.   A light source comprising the wavelength conversion element according to claim 11 and a light emitting element. The light source according to claim 13, wherein the light source is used for a projector .