JP2016213334A - Wavelength conversion member and light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength conversion member which is small in the decrease in light emission intensity with time when exposed to light of an LED or LD is applied.SOLUTION: A wavelength conversion member comprises: a sintered compact of a powder mixture of (a) glass powder including, as a glass composition, an alkali metal element and at least one element selected from Sn and Fe and (b) inorganic phosphor powder.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wavelength conversion member that converts the wavelength of light emitted from a light emitting diode (LED), a laser diode (LD), or the like into another wavelength.

  In recent years, as a next-generation light source that replaces fluorescent lamps and incandescent lamps, attention has been focused on light sources using LEDs and LDs from the viewpoints of low power consumption, small size and light weight, and easy light quantity adjustment. As an example of such a next-generation light source, for example, Patent Document 1 discloses a light source in which a wavelength conversion member that absorbs part of light from an LED and converts it into yellow light is disposed on an LED that emits blue light. 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 matrix is deteriorated by the light from the LED, and the luminance of the light source tends to be lowered. In particular, there is a problem that the resin matrix deteriorates due to heat emitted from 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 an inorganic phosphor powder is dispersed and fixed in a glass matrix instead of a resin matrix 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 heat of the LED chip or irradiation light, and problems such as discoloration and deformation hardly occur.

  However, the wavelength conversion member has a problem in that the inorganic phosphor powder is deteriorated due to a baking process at the time of manufacture, and luminance is easily deteriorated. In particular, in applications such as general lighting and special lighting, since high color rendering properties are required, it is necessary to use inorganic phosphor powder with relatively low heat resistance such as red and green, and the deterioration of inorganic phosphor powder is remarkable. Tend to be. Then, the wavelength conversion member using the glass which lowered the softening point by containing an alkali metal element is proposed (for example, refer to patent documents 4). Since the wavelength conversion member can be manufactured by firing at a relatively low temperature, deterioration of the inorganic phosphor powder in the firing step can be suppressed.

JP 2000-208815 A JP 2003-258308 A Japanese Patent No. 4895541 JP 2007-302858 A

  The wavelength conversion member containing an alkali metal element in the glass matrix has a problem that the emission intensity is likely to decrease with time (temperature quenching). With the further increase in the output of light sources such as LEDs and LDs in recent years, the above phenomenon has become more prominent.

  Accordingly, an object of the present invention is to provide a wavelength conversion member in which the phosphor is unlikely to deteriorate in the firing step during manufacturing, and has little decrease in light emission intensity over time when irradiated with light from an LED or LD. To do.

  The wavelength conversion member of the present invention contains (a) a glass powder containing at least one selected from an alkali metal element and Sn and Fe as a glass composition, and (b) an inorganic phosphor powder. It consists of a sintered body of mixed powder.

  As described above, when the wavelength conversion member containing an alkali metal element in the glass matrix is irradiated with light from a high-power LED or LD, the emission intensity tends to decrease with time. The present inventors have inferred the details of the cause as follows.

  When a glass matrix containing an alkali metal element in the composition is irradiated with excitation light, the energy of the excitation light excites the electrons present in the outermost shell of oxygen ions in the glass matrix and separates them from the oxygen ions. The part is combined with alkali ions in the glass matrix to form a colored center (here, after the alkali ions are released, vacancies are formed). On the other hand, the holes generated by the escape of electrons move in the glass matrix, and a part of the holes are captured by the vacancies formed after the escape of alkali ions to form a colored center. It is considered that these colored centers formed in the glass matrix serve as an absorption source of excitation light and fluorescence, and the emission intensity of the wavelength conversion member decreases.

  Therefore, in order to suppress the above phenomenon, the wavelength conversion member of the present invention contains at least one selected from Sn and Fe in the glass composition. Sn ions and Fe ions are likely to change in valence and can easily exchange electrons. For this reason, Sn ions and Fe ions have an action of giving electrons to the holes trapped in the coloring center and extinguishing the holes. On the other hand, Sn ions and Fe ions that have increased in valence by giving electrons to holes return to their original valence by depriving the electrons trapped in the coloring center. In other words, Sn ions and Fe ions play a role as electron carriers, depriving electrons from the colored centers that have captured the electrons, and giving electrons to the colored centers that are lacking electrons, thereby recombining electrons and holes. It is thought to promote. As a result, it is difficult for color centers to occur in the glass matrix, and it is possible to suppress a decrease in light emission intensity over time of the wavelength conversion member.

In the wavelength conversion member of the present invention, it is preferable that the glass powder contains 0.1 to 35% of Li ₂ O + Na ₂ O + K ₂ O in mol% in terms of oxide. In addition, in this specification, "(circle) + (circle) + ..." means the total amount of content of each component.

In the wavelength conversion member of the present invention, the glass powder preferably contains SnO + Fe ₂ O ₃ 0.001 to 10% in mol% in terms of oxide.

In the wavelength conversion member of the present invention, the glass powder is in mol% in terms of oxides, SiO ₂ 30-80%, B ₂ O ₃ 0-40%, Li ₂ O + Na ₂ O + K ₂ O 0.1-35%, MgO + CaO + SrO + BaO 0.1~45 %, and _preferably contains _{SnO + Fe 2 O 3 0.001~10%} .

In the wavelength converting member of the present invention, the glass powder is in mole percent oxide _{equivalent, SiO 2 35~85%, B 2} O 3 0~55%, Li 2 O 0~20%, Na 2 O 0~25 %, K ₂ O 0 to 25%, Li ₂ O + Na ₂ O + K ₂ O 0.1 to 35%, and SnO + Fe ₂ O ₃ 0.001 to 10% are preferably contained.

  In the wavelength conversion member of the present invention, the inorganic phosphor powder includes nitride phosphor, oxynitride phosphor, oxide phosphor, sulfide phosphor, oxysulfide phosphor, halide phosphor, and aluminate phosphor. It is preferably at least one selected from the body.

  The wavelength conversion member of the present invention is characterized in that an inorganic phosphor powder is dispersed in a glass matrix containing at least one selected from an alkali metal element and Sn and Fe as a glass composition. To do.

  The light-emitting device of the present invention includes the above-described wavelength conversion member and a light source that irradiates the wavelength conversion member with excitation light.

  According to the present invention, it is possible to provide a wavelength conversion member in which the phosphor is not easily deteriorated in the firing step at the time of manufacture, and when the light emitted from the LED or LD is irradiated, the decrease in emission intensity with time is small. Become.

It is a schematic diagram which shows one Embodiment of the light-emitting device of this invention.

  The wavelength conversion member of the present invention contains (a) a glass powder containing at least one selected from an alkali metal element and Sn and Fe as a glass composition, and (b) an inorganic phosphor powder. It consists of a sintered body of mixed powder. Below, each component is demonstrated in detail.

  The glass powder serves as a medium for stably holding the inorganic phosphor powder in the wavelength conversion member of the present invention. Here, since the reactivity with the inorganic phosphor powder during firing varies depending on the composition of the glass powder, it is preferable to select a glass composition suitable for the inorganic phosphor powder to be used.

The glass powder contains an alkali metal element (at least one selected from Li, Na and K) as a glass composition for the purpose of lowering the softening point. Specifically, the glass powder is the mole percent of the oxide _{equivalent, Li 2 O + Na 2 O} + K 2 O of from 0.1 to 35% 1 to 25%, and preferably in particular 2-20%. If the content of Li ₂ O + Na ₂ O + K ₂ O is too small, the above effect is difficult to obtain. On the other hand, if the content is too large, the chemical durability tends to decrease. In addition, as will be described later, it is preferable that the contents of Li ₂ O, Na ₂ O, and K ₂ O are appropriately set in accordance with the glass composition system.

Moreover, the glass powder can contain the at least 1 sort (s) selected from Sn and Fe, and can suppress the fall of the light emission intensity of the wavelength conversion member with time. Specifically, it is preferable that the glass powder contains 0.001 to 10%, 0.01 to 5%, particularly 0.1 to 3% of SnO + Fe ₂ O ₃ in mol% in terms of oxide. If the content of SnO + Fe ₂ O ₃ is too small, the above effect is difficult to obtain. On the other hand, if the content is too large, the glass powder itself tends to be colored and the emission intensity tends to decrease. The content of SnO and _Fe 2 _{O 3} is also preferably respectively within the above range. In particular, SnO is preferable because it can remarkably suppress a decrease in light emission intensity over time, and the glass powder itself is difficult to be colored.

The glass powder is SiO ₂ , B ₂ O ₃ , RO (R is at least one selected from Mg, Ca, Sr and Ba), R ′ ₂ O (R ′ is at least selected from Li, Na and K) What contains 10-99% by mol% of at least 1 sort (s) selected from 1 sort (s) is preferable. Specifically, SiO ₂ —B ₂ O ₃ —RO—R ′ ₂ O glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O glass, SiO ₂ —B ₂ O ₃ —ZnO—R ′ ₂ O glass etc. are mentioned.

Examples of the SiO ₂ —B ₂ O ₃ —RO—R ′ ₂ O-based glass include SiO ₂ 30 to 80%, B ₂ O ₃ 0 to 40%, Li ₂ O + Na ₂ O + K in terms of oxide equivalent mol%. _{2 O 0.1~35%, MgO + CaO} + SrO + BaO 0.1~45%, and _those containing SnO ₊ Fe 2 O 3 0.001~10% is preferred. The reason for limiting the glass composition in this way will be described below.

SiO ₂ is a component that forms a glass network. The content of SiO ₂ is preferably 30 to 80%, particularly preferably 40 to 60%. When the content of SiO ₂ is too small, chemical durability tends to decrease. On the other hand, if the content of SiO ₂ is too large, the softening point becomes high, so that high-temperature firing is necessary for sufficient sintering. As a result, the inorganic phosphor powder tends to deteriorate during firing.

B ₂ O ₃ is a component having a great effect of improving the meltability by lowering the melting temperature. The content of B ₂ O ₃ is preferably 0 to 40%, 1 to 35%, particularly preferably 5 to 30%. If the B ₂ O ₃ content is too large, chemical durability tends to decrease.

Li ₂ O, Na ₂ O and K ₂ O are components that lower the softening point. The content (total amount) of Li ₂ O, Na ₂ O and K ₂ O is preferably 0.1 to 35%, 1 to 25%, particularly preferably 2 to 20%. When the content of these components is too small, the softening point is difficult to decrease, while when too large, chemical durability and weather resistance are likely to decrease.

_{Incidentally,} Li 2 O, the preferred range of the content of each component of Na ₂ O and _{K 2} O is as follows. The content of Li ₂ O is preferably 0 to 15%, particularly preferably 0.1 to 10%. The content of Na ₂ O is preferably 0 to 15%, particularly preferably 0.1 to 10%. The content of K ₂ O is preferably 0 to 15%, particularly preferably 0.1 to 10%.

  MgO, CaO, SrO and BaO are components that improve the meltability by lowering the melting temperature. BaO also has an effect of suppressing the reaction with the inorganic phosphor powder. The content (total amount) of MgO, CaO, SrO and BaO is preferably 0.1 to 45%, 1 to 40%, particularly preferably 2 to 35%. If the content of these components is too small, it is difficult to obtain the above effect, while if too much, the chemical durability tends to decrease.

  In addition, the preferable range of content of each component of MgO, CaO, SrO, and BaO is as follows. The content of MgO is preferably 0 to 20%, particularly preferably 0 to 10%. The CaO content is preferably 0 to 30%, particularly preferably 0 to 20%. The SrO content is preferably 0 to 20%, particularly preferably 0 to 10%. The BaO content is preferably 0 to 40%, particularly preferably 0.1 to 30%.

The total amount and individual content of SnO and Fe ₂ O ₃ are as described above.

  In addition to the above components, the glass powder may contain the following components.

Al ₂ O ₃ is a component that improves chemical durability. The content of Al ₂ O ₃ is preferably 0 to 20%, particularly preferably 1 to 18%. When the content of Al ₂ O ₃ is too large, there is a tendency that the melting is lowered.

  ZnO is a component that improves the meltability by lowering the melting temperature. The content of ZnO is preferably 0 to 20%, particularly preferably 0.1 to 10%. When there is too much content of ZnO, chemical durability will fall easily.

For the purpose of improving chemical durability, Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ , La ₂ O ₃ , Y ₂ O ₃ , Bi ₂ O ₃ or ZrO ₂ is used. You may make it contain to 15%.

Examples of the SiO ₂ —B ₂ O ₃ —R ′ ₂ O glass include mol%, SiO ₂ 35 to 85%, B ₂ O ₃ 0 to 55%, Li ₂ O 0 to 20%, and Na ₂ O. _{0~25%, K 2 O 0~25%} , Li 2 O + Na 2 O + K 2 O 0.1~35%, and _those containing SnO ₊ Fe 2 O 3 0.001~10% is preferred. The reason for limiting the glass composition in this way will be described below.

SiO ₂ is a component that forms a glass network. The SiO ₂ content is preferably 35 to 85%, particularly preferably 45 to 80%. When the content of SiO ₂ is too small, chemical durability tends to decrease. On the other hand, if the content of SiO ₂ is too large, the softening point becomes high, so that high-temperature firing is necessary for sufficient sintering. As a result, the inorganic phosphor powder tends to deteriorate during firing.

B ₂ O ₃ is a component having a great effect of improving the meltability by lowering the melting temperature. The content of B ₂ O ₃ is preferably 0 to 55%, 0.1 to 45%, particularly 1 to 30%. If the B ₂ O ₃ content is too large, chemical durability tends to decrease.

Li ₂ O, Na ₂ O and K ₂ O are components that lower the softening point. The content (total amount) of Li ₂ O, Na ₂ O and K ₂ O is preferably 0.1 to 35%, 1 to 25%, particularly preferably 2 to 20%. When the content of these components is too small, the softening point is difficult to decrease, while when too large, chemical durability and weather resistance are likely to decrease.

_{Incidentally,} Li 2 O, the preferred range of the content of each component of Na ₂ O and _{K 2} O is as follows. The content of Li ₂ O is preferably 0 to 20%, particularly preferably 0.1 to 10%. The content of Na ₂ O is preferably 0 to 25%, particularly preferably 0.1 to 15%. The content of K ₂ O is preferably 0 to 25%, particularly preferably 0.1 to 15%.

In addition to the above components, MgO, CaO, SrO, and BaO can be contained in a total amount of up to 30% and ZnO up to 10% in order to improve the meltability. In addition, P ₂ O ₅ is increased to 5% for improving the meltability, and Al ₂ O ₃ , Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O for improving the chemical durability. ₃ or La ₂ O ₃ may be contained up to 15% each.

Examples of the SiO ₂ —B ₂ O ₃ —ZnO—R ′ ₂ O glass include mol%, SiO ₂ 5-50%, B ₂ O ₃ 10-55%, ZnO 30-80%, Li ₂ O. _{0~20%, Na 2 O 0~20%} , K 2 O 0~20%, Li 2 O + Na 2 O + K 2 O 0.1~25%, 0~10% MgO, CaO 0~10%, SrO 0~ 10%, BaO 0%, and _those containing SnO ₊ Fe 2 O 3 0.001~10% is preferred. In addition to the above components, in order to improve chemical durability, Al ₂ O ₃ is up to 5%, Ta ₂ O ₅ , TiO ₂ , Nb ₂ O ₅ , Gd ₂ O ₃ or La ₂ O ₃ is 15%. You may make it contain.

The particle size of the glass powder is not particularly limited, for example, the maximum particle diameter _{D 99} is 200μm or less (especially 150μm or less, more 105μm or less), and an average particle diameter _{D 50} of more than 0.1 [mu] m (in particular 1μm or more, further Is preferably 2 μm or more. If the maximum particle diameter D ₉₉ of the glass powder is too large, in the wavelength conversion member obtained, luminous efficiency becomes excitation light is less likely to scatter tends to decrease. When the average particle diameter D ₅₀ is too small, in the wavelength conversion member obtained, luminous efficiency tends to decrease with the excitation light is excessively scattered.

In the present invention, the average particle diameter D ₅₀ and the maximum particle diameter D ₉₉ indicate values measured by a laser diffraction method.

  The inorganic phosphor powder is not particularly limited as long as it is generally available on the market. For example, nitride phosphor powder, oxynitride phosphor powder, oxide phosphor powder (including garnet phosphor powder such as YAG phosphor powder), sulfide phosphor powder, oxysulfide phosphor powder, halogen Fluoride phosphor powder (halophosphate chloride, etc.) and aluminate phosphor powder. Of these inorganic phosphor powders, nitride phosphor powders, oxynitride phosphor powders and oxide phosphor powders are preferable because they have high heat resistance and are relatively unlikely to deteriorate during firing. The nitride phosphor powder and the oxynitride phosphor powder are characterized by converting near-ultraviolet to blue excitation light into a wide wavelength region from green to red and having a relatively high emission intensity. Therefore, the nitride phosphor powder and the oxynitride phosphor powder are particularly effective as inorganic phosphor powders used for the wavelength conversion member for white LED elements.

  Examples of the inorganic phosphor powder include those having an excitation band at a wavelength of 300 to 500 nm and an emission peak at a wavelength of 380 to 780 nm, particularly blue (wavelength 440 to 480 nm), green (wavelength 500 to 540 nm), yellow (wavelength 540). ˜595 nm) or red light (wavelength 600 to 700 nm).

Examples of inorganic phosphor powder that emits blue light when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm include (Sr, Ba) MgAl ₁₀ O ₁₇ : Eu ²⁺ , (Sr, Ba) ₃ MgSi ₂ O _8. : Eu ^{2+ and the} like.

As inorganic phosphor powders that emit green fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm, SrAl ₂ O ₄ : Eu ²⁺ , SrBaSiO ₄ : Eu ²⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ , SrSiO _n : Eu ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ , Ba ₂ MgSi ₂ O ₇ : Eu ²⁺ , Ba ₂ SiO ₄ : Eu ²⁺ , Ba ₂ Li ₂ Si ₂ O ₇ : Eu ²⁺ , BaAl ₂ O ₄ : Eu ^{2+ and the} like.

As inorganic phosphor powders that emit green fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm, SrAl ₂ O ₄ : Eu ²⁺ , SrBaSiO ₄ : Eu ²⁺ , Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ , SrSiOn: Eu ²⁺ , β-SiAlON: Eu ^{2+ and the} like.

Examples of the inorganic phosphor powder that emits yellow fluorescence when irradiated with excitation light having a wavelength of 300 to 440 nm include La ₃ Si ₆ N ₁₁ : Ce ³⁺ .

Examples of the inorganic phosphor powder that emits yellow fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ and Sr ₂ SiO ₄ : Eu ²⁺ .

Inorganic phosphor powders that emit red fluorescence when irradiated with ultraviolet to near-ultraviolet excitation light having a wavelength of 300 to 440 nm include CaGa ₂ S ₄ : Mn ²⁺ , MgSr ₃ Si ₂ O ₈ : Eu ²⁺ , Mn ²⁺ , Ca _{2. ^{MgSi 2 O 7: Eu 2+,}} Mn 2+ , and the like.

Inorganic phosphor powders that emit red fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include CaAlSiN ₃ : Eu ²⁺ , CaSiN ₃ : Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , α-SiAlON: Eu ^{2+ and the} like can be mentioned.

  A plurality of inorganic phosphor powders may be mixed and used in accordance with the wavelength range of excitation light or light emission. For example, when white light is obtained by irradiation with ultraviolet excitation light, inorganic phosphor powders emitting blue, green, yellow, and red fluorescence may be mixed and used.

  When there is too much content of the inorganic fluorescent substance powder in a wavelength conversion member, it will become difficult to sinter or there exists a tendency for a porosity to become large. As a result, in the obtained wavelength conversion member, problems such as it becomes difficult for the excitation light to be efficiently irradiated onto the inorganic phosphor powder, and the mechanical strength tends to decrease. On the other hand, when there is too little content of inorganic fluorescent substance powder, it will become difficult to obtain desired luminescence intensity. From such a viewpoint, the content of the inorganic phosphor powder in the wavelength conversion member is mass%, preferably 0.01 to 50%, more preferably 0.05 to 40%, and still more preferably 0.1 to 30. % Is adjusted.

  Note that the wavelength conversion member for the purpose of reflecting the fluorescence generated in the wavelength conversion member to the excitation light incident side and mainly taking out only the fluorescence to the outside is not limited to the above, and the emission intensity is maximized. As described above, the content of the inorganic phosphor powder can be increased (for example, in mass%, 50% to 80%, and further 55 to 75%).

  The wavelength conversion member of this invention is manufactured by baking the mixed powder containing said glass powder and inorganic powder. Thereby, the wavelength conversion member by which inorganic fluorescent substance powder disperse | distributes in the glass matrix containing at least 1 sort (s) selected from an alkali metal element and Sn and Fe as a glass composition is obtained.

  The firing temperature is appropriately adjusted within the softening point of the glass powder within ± 150 ° C, preferably within ± 100 ° C. If the firing temperature is too low, the glass powder does not flow sufficiently and it is difficult to obtain a dense sintered body. On the other hand, if the firing temperature is too high, the inorganic phosphor powder may elute into the glass powder and the emission intensity may decrease. Or the component contained in inorganic fluorescent substance powder may diffuse and color in glass powder, and there exists a possibility that emitted light intensity may fall.

Note that firing is preferably performed in a reduced-pressure atmosphere. Specifically, the firing atmosphere is preferably less than 1.013 × 10 ⁵ Pa, more preferably 1000 Pa or less, and even more preferably 400 Pa or less. Thereby, the amount of bubbles remaining in the wavelength conversion member can be reduced. As a result, the light scattering factor in the wavelength conversion member can be reduced, and the luminous efficiency can be improved. In addition, you may perform the whole baking process in a pressure-reduced atmosphere, for example, only a baking process is performed in a pressure-reduced atmosphere, and the temperature raising process and temperature-falling process before and behind that are performed in the atmosphere (for example, under atmospheric pressure) which is not a pressure-reduced atmosphere. You may go.

  The shape of the wavelength conversion member of the present invention is not particularly limited. For example, a plate shape, a column shape, a spherical shape, a hemispherical shape, a hemispherical dome shape, etc. It may be a film formed on the surface of the substrate.

  FIG. 1 shows an embodiment of a light emitting device of the present invention. As shown in FIG. 1, the light emitting device 1 includes a wavelength conversion member 2 and a light source 3. The light source 3 irradiates the wavelength conversion member 2 with excitation light L1. The excitation light L1 incident on the wavelength conversion member 2 is converted into fluorescence L2 having a different wavelength and is emitted from the side opposite to the light source 3. At this time, the combined light of the excitation light L1 transmitted without being wavelength-converted and the fluorescence L2 may be emitted.

  Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.

(1) Production of glass powder Tables 1 and 2 show glass powders used in Examples (a-2 to a-3, b-2 to b-3, c-2 to c-3, d-2 to d- 3, e-2 to e-3, f-2 to f-3, g-2 to g-3) and glass powders (a-1, b-1, c-1, d-1) used in comparative examples , E-1, f-1, g-1).

First, the raw materials were prepared so as to have the compositions shown in Tables 1 and 2. The raw material was melted and vitrified in a platinum crucible at a temperature of 1100 to 1500 ° C. for 1 to 2 hours, and the molten glass was cast between a pair of cooling rollers to form a film. After the film-shaped glass was pulverized by a ball mill, the average particle diameter D ₅₀ and classified to obtain a glass powder 2.5 [mu] m.

The softening point and density of each glass powder were measured using a sample obtained by forming molten glass into a columnar shape or a block shape according to each measurement and annealing. For the softening point, a fiber elongation method was used, and a temperature at which the viscosity was 10 ^7.6 dPa · s was adopted. The density was determined by the Archimedes method.

(2) Production of Wavelength Conversion Member Tables 3 to 8 show examples of the present invention (1-2 to 1-3, 2-2 to 2-3, 3-2-3-3, 4-2 to 4- 3, 5-2 to 5-3, 6-2 to 6-3, 7-2 to 7-3, 8-2 to 8-3, 9-2 to 9-3, 10-2 to 10-3, 11-2 to 11-3, 12-2 to 12-3, 13-2 to 13-3, 14-2 to 14-3, 15-2 to 15-3, 16-2 to 16-3, 17- 2-17-3, 18-2 to 18-3, 19-2 to 19-3, 20-2 to 20-3, 212-2 to 21-3) and comparative examples (1-1, 2-1, 3-1, 4-1, 5-1, 6-1, 7-1, 8-1, 9-1, 10-1, 11-1, 12-1, 13-1, 14-1, 15- 1, 16-1, 17-1, 18-1, 19-1, 20-1, 21-1).

In Tables 3 and 4, Y ₃ (Al, Gd) ₅ O ₁₂ : Ce ³⁺ (YAG) phosphor powder is used in Tables _{3 and} 4, and in Tables 5 and 6, (Ca, Sr) is used. ₂ Si ₅ N ₈ : Eu ²⁺ (SCASN) phosphor powder was mixed with a predetermined amount of α-SiAlON: Eu ²⁺ (α-SiAlON) phosphor powder in Tables 7 and 8 to obtain a mixed powder. The mixed powder was pressure-molded with a mold to prepare a cylindrical preform with a diameter of 1 cm. By processing the sintered body obtained by firing the preform at the temperatures shown in Tables 1 and 2, a 1.2 mm square, 0.2 mm thick wavelength conversion member was obtained.

  The obtained wavelength conversion member was placed on an LED chip having an emission wavelength of 445 nm, energized at 700 mA, and continuously irradiated for 100 hours in an integrating sphere. The energy distribution spectrum (emission spectrum) of the light emitted from the upper surface of the wavelength conversion member was measured using a general-purpose emission spectrum measuring device. The total luminous flux value was calculated by multiplying the obtained emission spectrum by the standard relative luminous sensitivity. The change rate of the total luminous flux value was expressed as a value (%) obtained by dividing the total luminous flux value after irradiation for 100 hours by the total luminous flux value before irradiation and multiplying by 100.

  As is apparent from Tables 3 to 8, the wavelength conversion members of the examples can suppress the decrease in the total luminous flux value after 100 hours of excitation light irradiation, as compared with the corresponding wavelength conversion members of the comparative examples. It was.

  The wavelength conversion member of the present invention is suitable as a structural member for general illumination such as white LEDs and special illumination (for example, a projector light source and a headlamp light source of an automobile).

DESCRIPTION OF SYMBOLS 1 Light emitting device 2 Wavelength conversion member 3 Light source

Claims (8)

  (A) As a glass composition, from a sintered powder of a mixed powder containing an alkali metal element and glass powder containing at least one selected from Sn and Fe; and (b) inorganic phosphor powder. The wavelength conversion member characterized by becoming. _2. The wavelength conversion member according to claim 1, wherein the glass powder contains Li ₂ O + Na ₂ O + K ₂ O 0.1 to 35% in mol% in terms of oxide. The wavelength conversion member according to claim 1, wherein the glass powder contains SnO + Fe ₂ O ₃ 0.001 to 10% in mol% in terms of oxide. Glass powder, in mol% of the oxide _{equivalent, SiO 2 30~80%, B 2} O 3 0~40%, Li 2 O + Na 2 O + K 2 O 0.1~35%, MgO + CaO + SrO + BaO 0.1~45%, _and, the wavelength converting member according to any one of claims 1 to 3, characterized in that it contains _{SnO + Fe 2 O 3 0.001~10%} . Glass powder, in mol% of the oxide _{equivalent, SiO 2 35~85%, B 2} O 3 0~55%, Li 2 O 0~20%, Na 2 O 0~25%, K 2 O 0~25 _{%, Li 2 O + Na 2} O + K 2 O 0.1~35%, and _the wavelength of any one of claims 1 to 3, characterized in that it contains SnO ₊ Fe 2 O 3 0.001~10% Conversion member.   The inorganic phosphor powder is at least one selected from a nitride phosphor, an oxynitride phosphor, an oxide phosphor, a sulfide phosphor, an oxysulfide phosphor, a halide phosphor, and an aluminate phosphor The wavelength conversion member according to any one of claims 1 to 5, wherein the wavelength conversion member is.   A wavelength conversion member comprising an inorganic phosphor powder dispersed in a glass matrix containing, as a glass composition, an alkali metal element and at least one selected from Sn and Fe.   A light emitting device comprising: the wavelength conversion member according to claim 1; and a light source that irradiates the wavelength conversion member with excitation light.

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