JP2016084269A - Phosphor-dispersed glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phosphor-dispersed glass excellent in moisture resistance even without containing NbOin a glass component.SOLUTION: The phosphor-dispersed glass having phosphor dispersed in glass is provided in which the glass is substantially free of NbOand contains by mass%: 15 to 40% of SiO; 10 to 30% of BO; 1 to 35% of ZnO; 0 to 20% of AlO; 2 to 30% in total of at least one kind selected from a group consisting of BaO, CaO and SrO; 0 to 1% of MgO; 5 to 35% in total of RO (at least one kind selected from LiO, NaO and KO); and 0 to 15% in total of at least one kind selected from a group consisting of antimony oxide and tin oxide.SELECTED DRAWING: None

Description

  The present invention relates to a phosphor-dispersed glass in which a phosphor that is a material for converting the wavelength of light is dispersed in glass.

  2. Description of the Related Art Conventionally, light emitting devices that use light emitting diodes (LEDs), laser diodes (LDs), and the like as light sources and convert the wavelength of light emitted from the light sources with phosphors to obtain light of a desired color or wavelength are widely known ( For example, Patent Documents 1 to 4).

  In recent years, various developments have been made on light emitting devices using LEDs and LDs as light sources. As one of such light emitting devices, for example, development for obtaining white light using an LED as a light source has been made, and a power-saving and high color rendering white light source has been realized. Currently, a commercially available white light source uses a blue GaN-based LED as a light source, and a yellow phosphor that converts part of the blue light emitted from the LED into yellow, depending on the blue light and the phosphor of the light source. A mixture of the converted yellow light and pseudo white light is used. A cerium-doped YAG oxide phosphor is widely used as the phosphor.

  When a phosphor is used as an LED light source or an LD light source, in most cases, an epoxy resin, a silicone resin, or a fluororesin is used to form a structural seal so that the mixture of the phosphor and the resin covers the light source. . However, there is a problem that the resin deteriorates due to heat generation of the LED or LD, ultraviolet rays or blue light emitted from the LED or LD, and the discoloration or light transmission property is deteriorated. Further, depending on the phosphor, there is a case where it is damaged by moisture, and there is a problem that the phosphor is deactivated when moisture in the environment permeates a resin as a sealing material.

Therefore, attention has been focused on glass having a high water barrier property and higher durability against heat and light than a resin as a sealing member. For example, as shown in Patent Documents 5 and 6, a sintered body (hereinafter sometimes referred to as “phosphor-dispersed glass”) in which phosphor powder is mixed with glass powder and the mixture is sintered. Used to seal the LED. Patent Document 5 discloses a white light source obtained by mixing and sintering a powder of an oxide phosphor and SnO—P ₂ O ₅ —ZnO glass, and Patent Document 6 has a softening point of 650 ° C. or lower. , A luminescent color conversion material having weather resistance composed of SiO ₂ —TiO ₂ —Nb ₂ O ₅ —R ₂ O (R is Li, Na, K) glass substantially free of PbO has been reported. .

  As a method for sealing an LED using the glass powder and the phosphor powder as described above, for example, in Patent Document 5, a mixture of the glass powder and the phosphor powder is sintered to form a phosphor-dispersed glass, A method of sealing the LED by placing the phosphor-dispersed glass on the LED and then softening and flowing, or covering the LED with a mixed powder and then softening and flowing the powder to seal the LED A method for simultaneously forming a phosphor-dispersed glass is disclosed. In Patent Document 6, a glass powder, a phosphor powder, a binder, a solvent, and the like are kneaded to form a paste, and the paste is applied on the LED and then fired to seal the phosphor-dispersed glass and the LED. And a method of forming a green sheet using the same material as the paste, laminating the green sheet on the LED, thermocompression bonding, and firing.

  Patent Document 7 describes that sulfide phosphors, aluminate phosphors and silicate phosphors are inferior in moisture resistance. In this document, the phosphor is not produced by a sol-gel method using water when producing a phosphor-dispersed glass, and the phosphor is dispersed by mixing and baking the glass powder and the phosphor powder, thereby obtaining the phosphor described above. It solves the problem that the phosphor is damaged by moisture when manufacturing the dispersion glass.

  As described above, by sealing the LED or LD, which is a light source, using the phosphor-dispersed glass in which the phosphor is dispersed in the glass, heat, light, and air that have been a problem with conventional resin sealing Although a light emitting device with improved durability against moisture in the interior can be realized, when actually manufacturing a phosphor-dispersed glass or sealing the light source, the mixture of the phosphor powder and the glass powder has a temperature above the glass transition point. It is necessary to sinter and raise the temperature, and the phosphor may be deactivated by heat applied at that time.

It has been reported that when a nitride phosphor is heated in an environment where oxygen is present, the phosphor is deactivated (Non-Patent Document 1). Non-Patent Document 1 reports that Sr _2−x Si ₅ N ₈ : Eu ²⁺ phosphor is oxidized to trivalent divalent Eu when oxygen is present during heating. That is, when the nitride phosphor and glass containing oxygen are mixed and sintered, the light emission efficiency of the nitride phosphor may be significantly reduced.

In addition to the oxynitride phosphors described above, sulfide phosphors, halide phosphors, aluminate phosphors, and the like have a large luminous efficiency due to the heat generated when firing the glass powder and phosphor powder. May be reduced. For example, in Patent Document 8, phosphor powder having low heat resistance as described above is mixed and sintered with ZnO—B ₂ O ₃ —SiO ₂ glass powder having a softening point of around 600 ° C. A phosphor-dispersed glass with suppressed deactivation has been reported.

JP 2009-277516 A JP 2012-155003 A JP 2003-258308 A Japanese Patent No. 5045432 JP 2005-11933 A JP 2007-302858 A JP 2009-177131 A JP 2007-191702 A

Yeh CW et al. "Origin of thermal degradation of Sr (2-x) Si5N8: Eu (x) phosphors in air for light-emitting diodes," J. Am. Chem. Soc., 134, 14108-14117 (2012) .

  As described above, when using a phosphor-dispersed glass as a material for sealing a light source such as an LED or LD, the phosphor-dispersed glass is heated during the sintering of the phosphor powder and the glass powder or to seal the light source. When doing so, the phosphor may be deactivated by heat. For this reason, it is desirable to use a glass having a low softening point. On the other hand, a glass having a low softening point may be chemically unstable due to a decrease in weather resistance, particularly moisture resistance. A glass with low moisture resistance has a problem that the components contained in the glass are eluted or salt is deposited due to moisture in the atmosphere after long-term use, resulting in a decrease in light transmittance, resulting in a decrease in luminous efficiency. is there.

For example, Patent Document 6 discloses a luminescent color conversion material having weather resistance using SiO ₂ —TiO ₂ —Nb ₂ O ₅ —R ₂ O-based glass. The luminescent color conversion material imparts weather resistance, particularly moisture resistance, to the oxide glass powder by containing TiO ₂ and Nb ₂ O ₅ as essential components.

On the other hand, however, Nb ₂ O ₅ is expensive and expensive as a glass raw material. Therefore, the phosphor dispersion has improved moisture resistance without using an expensive raw material like Nb ₂ O _5. The demand for glass is still high.

Accordingly, an object of the present invention is to obtain a phosphor-dispersed glass excellent in moisture resistance even if Nb ₂ O ₅ is not contained in the glass component.

  Normally, when an alkali metal is contained in a glass component, the alkali component is eluted on the glass surface due to moisture in the atmosphere. On the other hand, when an alkaline earth metal is contained in the glass component, the glass surface is salted by moisture in the atmosphere. It is known that it is not preferable as a component for improving the moisture resistance. As described above, the glass in which the alkali is eluted or the salt is deposited has a reduced light transmittance, so that the luminous efficiency is impaired even if there is no problem such as deactivation of the phosphor dispersed inside. End up. However, as a result of intensive studies by the present inventors, it has been found that when the content of BaO in the glass component is increased, the moisture resistance is remarkably improved. In addition, when other alkaline earth metals were examined, the same tendency was observed for CaO and SrO. On the other hand, it was found that when MgO was contained in the glass component, the moisture resistance was greatly impaired. .

That is, the present invention relates to a phosphor-dispersed glass in which a phosphor is dispersed in glass. The glass does not substantially contain Nb ₂ O ₅ , and is in mass%, SiO ₂ is 15 to 40%, B ₂ O _3. 10 to 30%, ZnO 1 to 35%, Al ₂ O ₃ 0 to 20%, at least one selected from the group consisting of BaO, CaO, and SrO in total 2 to 30%, MgO 0 to 1%, R ₂ O (at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O) in total 5 to 35%, and at least selected from the group consisting of antimony oxide and tin oxide It is a phosphor-dispersed glass characterized by containing one kind in a total of 0 to 15%.

As described above, it is possible to improve the moisture resistance by increasing the content of BaO, but it has been found that the external quantum efficiency of the phosphor tends to decrease as the content of BaO increases. On the other hand, it was found that when the content of B ₂ O ₃ in the glass component is increased, the external quantum efficiency of the phosphor tends to increase although the moisture resistance decreases. The present invention achieves both moisture resistance and good light emission by making each component of the glass within the range described above.

  In this specification, moisture resistance was evaluated by the following moisture resistance test of glass. In addition, when the moisture resistance of the glass is excellent, the moisture resistance of the phosphor-dispersed glass is also excellent.

  First, glass powder was pressure-molded with a mold to prepare a button-shaped preform having a diameter of 20 mm and a thickness of 2 mm. Next, the molded body was sintered by heating in the air for 30 minutes to obtain a glass sintered body. After the obtained glass sintered body was polished to a thickness of 1 mm, the ultraviolet / visible light transmittance (wavelength 550 nm) before the test was measured using a spectrophotometer (U4000, manufactured by HITACHI).

  Next, an actual moisture resistance test was performed. The obtained sintered body is allowed to stand for 24, 48, 72, and 96 hours in a PCT (saturated pressurized steam test) at a temperature of 121 ° C. and a humidity of 100%, and then subjected to UV / visible light after the moisture resistance test. The transmittance (wavelength 550 nm) was measured in the same manner as described above, and the reduction rate of the transmittance by a moisture resistance test was determined. In addition, the decreasing rate of the transmittance was calculated from the formula {1- (transmittance after the moisture resistance test / transmittance before the test)} × 100 (%). In the present specification, when the calculated decrease rate of the transmittance decrease is 1% or less, the moisture resistance is good (◯), and when the decrease rate exceeds 1%, the moisture resistance is poor (x).

  The “phosphor-dispersed glass” of the present invention can be obtained, for example, by preparing the glass powder of the glass described above, mixing the glass powder and the phosphor, and then sintering the glass powder.

According to the present invention, it is possible to obtain a phosphor-dispersed glass excellent in moisture resistance without using an expensive material such as Nb ₂ O ₅ .

The present invention relates to a phosphor-dispersed glass in which a phosphor is dispersed in glass, and the glass does not substantially contain Nb ₂ O ₅ , and is in mass%, SiO ₂ is 15 to 40%, and B ₂ O ₃ is contained. 10 to 30%, ZnO 1 to 35%, Al ₂ O ₃ 0 to 20%, at least one selected from the group consisting of BaO, CaO and SrO in total 2 to 30%, MgO 0 to 1 %, R ₂ O (at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O) in total 5 to 35%, and at least 1 selected from the group consisting of antimony oxide and tin oxide It is a phosphor-dispersed glass characterized in that it contains 0 to 15% of seeds in total.

  Hereinafter, the composition of the glass of the present invention will be described. In addition, "%" which shows content of the component contained in glass shows the mass%, and may be described as "%" below.

In the glass used in the present invention, the components contained in the glass are SiO ₂ , B ₂ O ₃ , ZnO, Al ₂ O ₃ , BaO, CaO, SrO, R ₂ O, tin oxide and antimony oxide. The components are 100% in total. Moreover, the arbitrary component normally accept | permitted as a glass component may be contained to about 15%.

Examples of the optional component include WO ₃ and CeO ₂ represented by general oxides.

Further, as described above, the present invention is a phosphor-dispersed glass with improved moisture resistance without containing Nb ₂ O ₅ which is an expensive raw material. Accordingly, Nb ₂ O ₅ is not substantially contained. The “substantially not containing” may be, for example, less than 0.01%. Further, when manufacturing the above-described glass and phosphor dispersion glass may be not intentionally added Nb ₂ O _5.

Nb ₂ O ₅ and TiO ₂ are components having absorption in the ultraviolet region, and the efficiency of light emission may be reduced depending on the type of light source. Therefore, it is preferable that the above components are not substantially contained because unnecessary absorption of excitation light by glass can be suppressed when an ultraviolet light source is used. For example, Nb ₂ O ₅ + TiO ₂ may be 0.3% or less.

  Further, when PbO is contained in the glass, the glass is colored yellow and absorbs excitation light. Therefore, it is preferable that PbO is not substantially contained. Specifically, the content of the above components is preferably 0.3% by mass or less, more preferably 0.03% by mass or less.

Bi ₂ O ₃ is well known as a component that lowers the softening point of glass. However, if it is contained in the glass, it reacts with the phosphor and may deactivate the phosphor. _It is preferable not to contain ₂ O ₃ . Specifically, the content of the above components is preferably 0.3% by mass or less, more preferably 0.03% by mass or less.

In other words, the present invention preferably does not substantially contain PbO and Bi ₂ O ₃ in the glass component.

SiO ₂ is a glass forming component, and can coexist with B ₂ O ₃ , which is another glass forming component, to form a stable glass and is contained in the range of 15 to 40%. If it is less than 15%, it will deviate from the range of the glass whose moisture resistance is improved by BaO, and if it exceeds 40%, the softening point of the glass tends to increase. Preferably, the lower limit may be 20 or more, more preferably 22 or more. The upper limit value is preferably 35% or less, more preferably 30% or less.

B ₂ O ₃ is a glass forming component, facilitates glass melting, and suppresses an excessive increase in the linear expansion coefficient of glass. Moreover, in this invention, it suppresses that the light emission of a fluorescent substance falls by BaO, and it is made to contain in 10 to 30% of range in glass. If it is less than 10%, it will not vitrify, and if it exceeds 30%, the moisture resistance tends to be greatly reduced. The lower limit is preferably 15% or more, more preferably 16% or more, and the upper limit is preferably 28% or less.

  ZnO lowers the softening point of the glass and improves the moisture resistance of the glass, and is contained in the range of 1 to 35% in the glass. If it is less than 1%, the above-mentioned effect cannot be expected, and if it exceeds 35%, the light emission of the phosphor tends to decrease. Preferably, the lower limit may be 3% or more, more preferably 5% or more. The upper limit is preferably 25% or less, more preferably 18% or less.

Al ₂ O ₃ is a component that suppresses devitrification during glass melting and sintering, and is contained in a range of 0 to 20%. If it exceeds 20%, the stability of the glass is lowered. More preferably, it is 15% or less. Further, the lower limit is preferably 1% or more, more preferably 3% or more.

  The present invention contains BaO, CaO, and SrO so that at least one selected from the group consisting of BaO, CaO, and SrO is 2 to 30% in total. The above three components lower the softening point of the glass and improve the moisture resistance of the glass as described above. Moreover, only one type of the above components may be used, or two or more types may be used. If BaO + CaO + SrO is less than 2%, the moisture resistance will not be improved, and if it exceeds 30%, the balance of the glass composition will be lost and the moisture resistance will deteriorate, and the softening point of the glass will tend to be high. The lower limit is preferably 3% or more, more preferably 6% or more, still more preferably 10% or more, and the upper limit may be 25% or less.

  BaO is a component that improves moisture resistance and is preferably contained within a range of 1 to 30%. Alkaline earth metals other than MgO improve the moisture resistance of the glass, but using BaO is preferable because the moisture resistance is easily improved. The lower limit value is more preferably 2% or more, still more preferably 4% or more, and the upper limit value is more preferably 25% or less.

  CaO and SrO are components that improve the moisture resistance of the glass in the same manner as BaO, and are preferably contained within a range of 0 to 20%.

  In the present invention, when MgO is included, the moisture resistance is greatly impaired, so the content of MgO is in the range of 0 to 1%. Moreover, it is preferable not to contain substantially. “Substantially free” may be, for example, less than 1%, preferably 0.3% or less, more preferably 0.03% or less.

R ₂ O (total of at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O) lowers the softening point of the glass and adjusts the linear expansion coefficient to an appropriate range. It is contained in the range of 35%. If it is less than 5%, the softening point tends to be high, and if it exceeds 35%, the alkali elution amount increases and the moisture resistance decreases. Preferably it is good also as 6% or more and 30% or less.

Of the above R ₂ O components, Li ₂ O has the effect of lowering the softening point of the glass, but on the other hand, the glass tends to crystallize as the content increases. Good.

It is presumed that antimony oxide is contained in the form of Sb ₂ O ₃ and Sb ₂ O _{5 in} the glass. Further, it is presumed that tin oxide is contained in the form of SnO 2 _(2-x) (where 0 ≦ x <2), and for example, it is considered that SnO ₂ exists as SnO ₂ or SnO. Antimony oxide and tin oxide suppress the reactivity of the phosphor and glass, and when they are contained within the total range of 0 to 15%, the phosphor and glass react with heat during sintering. It is possible to suppress the deactivation of the phosphor. Moreover, Preferably it is 0.1 to 12%, More preferably, it is good also as 1 to 10%.

  Moreover, it is preferable to contain at least 0.1 mass% of antimony oxide and tin oxide, respectively. More preferably, it may be 1 to 15%, and more preferably 1 to 10%.

In addition to the components described above, ZrO ₂ may be added in order to suppress devitrification at the time of melting or sintering of the glass and improve the chemical durability of the glass. It is preferable to contain. If it exceeds 5%, the stability of the glass is lowered. Preferably it is the range of 3 mass% or less.

  The glass of the present invention preferably has a linear expansion coefficient at 30 ° C. to 300 ° C. of 6 to 13 ppm / ° C. and a softening point of 670 ° C. or less. By lowering the softening point, it is possible to suppress the phosphor from being deactivated by heat during sintering. Preferably it is 650 degrees C or less, More preferably, it is good also as 630 degrees C or less. Moreover, since moisture resistance may fall when a softening point becomes too low, it is good also considering a lower limit as 400 degreeC or more preferably.

  Usually, phosphors have different wavelengths for emitting excitation light depending on components constituting the phosphors. The type of the light source may be appropriately selected according to the excitation wavelength of the phosphor if it is an LED or LED, but the present invention particularly selects the type of phosphor if the phosphor has excitation light at a wavelength of 350 to 500 nm. Without limitation, it can be used for phosphor-dispersed glass. That is, the phosphor used in the present invention preferably has excitation light at a wavelength of 350 to 500 nm.

  Examples of the phosphor particles include at least selected from the group consisting of oxides, oxynitrides, nitrides, oxysulfides, sulfides, aluminate chlorides, halophosphate chlorides, fluorides, and YAG compounds. One type is preferably used. Since the present invention can be used even with nitride phosphors and sulfide phosphors generally considered to be easily deactivated, more preferably, oxides, oxynitrides, nitrides, oxysulfides, And sulfides. A plurality of types of phosphors may be used.

Examples of the nitride phosphors include (Sr, Ca) AlSiN ₃ : Eu phosphors, CaAlSiN ₃ : Eu phosphors as red phosphors, and La ₃ Si ₆ N ₁₁ : Ce phosphors as yellow phosphors, As oxynitride fluorescence, for example, red phosphor, CaAlSi (ON) ₃ : Eu phosphor, α-Sialon: Eu phosphor, green phosphor, β-Sialon: Eu phosphor, (Sr, Ba) Si ₂ O ₂ N ₂ : Eu phosphor, Ba ₃ Si ₆ O ₁₂ N ₂ : Eu phosphor.

As the oxide phosphor, for example, as a yellow phosphor, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce phosphor, Tb ₃ Al ₅ O ₁₂ : Ce phosphor, Lu ₃ Al ₅ O ₁₂ : Ce As phosphor, (Sr, Ca, Ba) ₂ SiO ₄ : Eu phosphor, green phosphor, Y ₃ (Al, Ga) ₅ O ₁₂ : Ce ³⁺ phosphor, (Ba, Sr) ₂ SiO ₄ : Eu fluorescence Body, CaSc ₂ O ₄ : Ce phosphor, BaMgAl ₁₀ O ₁₇ : Eu, Mn phosphor, SrAl ₂ O ₄ : Eu phosphor, red phosphor, (Sr, Ba) ₃ SiO ₅ : Eu phosphor etc. Can be mentioned.

As the sulfide phosphor, for example, a green phosphor, ZnS: Cu, Al phosphor, a (Ca, Sr) Ga ₂ S ₄ : Eu phosphor, and a red phosphor (Ca, Sr) S: Eu Examples of the phosphor and the near-infrared phosphor include (Zn, Cd) S: Cu phosphor. Examples of the oxysulfide phosphor include red phosphors such as Y ₂ O ₂ S: Eu phosphor, La ₂ O ₂ S: Eu phosphor, and Gd ₂ O ₂ S: Eu phosphor.

  In addition, the conversion efficiency (excitation light to fluorescence intensity ratio) and light emission efficiency of the phosphor-dispersed glass of the present invention vary depending on the type and content of phosphor particles dispersed in the glass and the thickness of the phosphor-dispersed glass. . The content of phosphor particles and the thickness of the phosphor-dispersed glass may be adjusted so as to optimize the luminous efficiency and color rendering properties. There arises a problem that phosphor particles are not efficiently irradiated. Moreover, when there is too little content, it will become difficult to make it fully light-emit. Therefore, it is preferable to mix so that content of the said fluorescent substance particle | grain may be 0.01-95 volume% with respect to the total mass of this fluorescent substance dispersion | distribution glass.

  The phosphor-dispersed glass of the present invention may contain an inorganic filler. By containing the inorganic filler, it is possible to adjust thermal properties such as a linear expansion coefficient and a softening point when the phosphor-dispersed glass is sintered. Examples of the inorganic filler that can be used include zircon, mullite, silica, titania, and alumina. Moreover, what is necessary is just to adjust content of this inorganic filler suitably, For example, you may mix so that it may become 0.1 mass% or more and 40 mass% or less with respect to the total mass of this fluorescent substance dispersion | distribution glass.

  As described above, the phosphor-dispersed glass of the present invention can be obtained by mixing glass powder and phosphor powder and then sintering them. At that time, it is preferable to mix the glass powder and the phosphor powder, and then form the pellet by a non-heating method such as pressurization, and sintering the pellet can suppress the deactivation of the phosphor derived from heat. . In addition to the above, after mixing the glass powder and the phosphor powder, the mixture may be heated to a moldable viscosity and molded using a mold or the like.

  The sintering temperature when performing the above-mentioned sintering is desirably in the range of 400 to 750 ° C. When the sintering temperature is higher than 750 ° C., the phosphor is deteriorated, or the glass and the phosphor react with each other, and the light emission efficiency is remarkably lowered, which is not suitable for the purpose of the present invention.

  The atmosphere at the time of heating may be the air, a reduced pressure or vacuum atmosphere, or an inert gas atmosphere such as nitrogen gas or Ar gas, but the air atmosphere is desirable in view of manufacturing costs. Furthermore, in order to suppress bubbles contained in the glass powder, the glass powder may be sintered under reduced pressure or in vacuum, or may be pressurized during sintering.

  As the glass powder used for the phosphor-dispersed glass, it is preferable to use a glass powder pulverized to a size close to the particle diameter (1 to 100 μm) of the phosphor powder generally used. The pulverization may be performed using a mortar or a ball mill, but a jet mill type pulverizer with less contamination in the work process may be used.

  In addition to the method of sintering the glass powder and phosphor powder pellets as described above to obtain phosphor-dispersed glass, glass powder, phosphor powder, binder, solvent, etc. are kneaded to form a paste. The phosphor-dispersed glass may be obtained from the paste. When using a paste, the phosphor-dispersed glass can be obtained by applying the paste to a substrate or the like and then sintering at a predetermined temperature. In addition, since said binder and solvent volatilize at the time of sintering, they do not remain in the phosphor-dispersed glass after sintering.

  In addition to the method described above, phosphor-dispersed glass may be obtained from a green sheet. The green sheet is made into a slurry by kneading glass powder, phosphor powder, plasticizer, binder, solvent, etc., and the slurry is molded on a film such as polyethylene terephthalate (PET) by a doctor blade method and dried. You can get a green sheet. By sintering the green sheet, a phosphor-dispersed glass can be obtained.

  The phosphor-dispersed glass of the present invention can be suitably used as a light emitting device having a phosphor-dispersed glass and an LED or LD. Examples of the light emitting device include white light sources as described above, projectors, sensors, laser light sources, and the like. Moreover, when using for a light-emitting device, the fluorescent substance which has a suitable wavelength conversion performance according to the objective use should just be selected.

  The phosphor-dispersed glass of the present invention can be suitably used as a white light source. When used for a white light source, the periphery of the LED, which is the light source, is sealed with the phosphor glass, whereby the wavelength of light emitted from the LED can be converted to generate white light. As a method of sealing the LED with the above phosphor glass, for example, a mixture of glass powder and phosphor powder is applied or adhered to the periphery of the LED and then heated and sintered, or the glass powder and phosphor Examples include a method in which a powder mixture is formed into a predetermined shape in advance to form a sintered body, and then placed on the LED surface using an adhesive material or the like. In addition, since a nitride phosphor that is particularly useful as a red phosphor can be sealed, a high color rendering white light source can be obtained.

  The phosphor-dispersed glass of the present invention can be suitably used as a light conversion member for a projector. When used for a light conversion member for a projector, the wavelength of light emitted from an LED is converted into light of each wavelength to generate green, yellow, and red. As a method for producing the light conversion member, a mixture of glass powder and phosphor powder is applied or adhered to the periphery of the LED, and then heated and sintered, or a mixture of the glass powder and phosphor powder is predetermined. Examples include a method of forming a sintered body by molding into a shape, and then installing the sintered body on the surface of the LED using an adhesive material or the like, a method of installing the sintered body at a position away from the LED by a predetermined distance, and the like.

  Examples of the present invention and comparative examples are described below.

1: Preparation of glass powder and evaluation of moisture resistance of glass First, various inorganic raw materials were weighed and mixed so as to have the compositions of AP described in Tables 1 and 2 to prepare raw material batches. This raw material batch was put into a platinum crucible and heated and melted in an electric heating furnace at 1100 to 1400 ° C. for 1 to 2 hours to obtain glass samples (A to P) shown in Tables 1 and 2. A part of the obtained glass was poured into a mold, made into a block shape, and used for measurement of thermophysical properties (linear expansion coefficient, softening point). The remaining glass was formed into flakes with a rapid cooling twin roll molding machine and sized with a pulverizer into glass powder having an average particle size of 1 to 30 μm and a maximum particle size of less than 200 μm.

In this example, SnO ₂ was used as a raw material for tin oxide and Sb ₂ O ₃ was used as a raw material for antimony oxide. Since tin oxide in the glass changes its oxidation state to SnO, SnO ₂ or the like and it is difficult to measure a clear oxidation state, it is described as SnO ₂ in Tables 1 and 2. In addition, since antimony oxide in the glass also takes an oxidation state such as Sb ₂ O ₃ or Sb ₂ O ₅ and it is difficult to measure a clear oxidation state, it is described as Sb ₂ O _{3 in the} table. In Tables 1 and 2, the content of each component is indicated by rounding off the second decimal place, so the apparent total value may not be 100.

  The average particle size and the maximum particle size were measured using a laser diffraction type particle size measuring device (manufactured by Nikkiso Co., Ltd., Microtrac). For measurement, after dispersing glass powder in water, laser light is irradiated to obtain scattered / diffracted light, and the particle size of glass powder is calculated from the light intensity distribution according to the program set in the device. And asked.

  The softening point was measured using a thermal analyzer TG-DTA (manufactured by Rigaku Corporation). Moreover, said linear expansion coefficient calculated | required the linear expansion coefficient from the amount of elongation at 30-300 degreeC when it heated up at 5 degree-C / min using the thermal dilatometer. Since K in Table 2 was not vitrified, the softening point and the coefficient of linear expansion were not measured and were not used for further study.

<Evaluation of moisture resistance of glass powder>
The obtained glass powders (A to J, L to P) were evaluated for moisture resistance by the following method. Glass powders A to H are within the scope of claim 1, and glass powders I to J and LP are outside the scope of claim 1.

  First, glass powder was pressure-molded with a mold to prepare a button-shaped preform having a diameter of 20 mm and a thickness of 2 mm. Next, it sintered by heating for 30 minutes in air | atmosphere, and obtained the glass sintered compact. After the obtained glass sintered body was polished to a thickness of 1 mm, the ultraviolet / visible light transmittance (550 nm) before the moisture resistance test was measured using a spectrophotometer (U4000, manufactured by HITACHI).

  Next, a moisture resistance test was performed. The obtained sintered body was allowed to stand for 24, 48, 72, and 96 hours under conditions of a temperature of 121 ° C. and a humidity of 100% by PCT (saturated pressurized steam test), and then transmitted through ultraviolet and visible light after the moisture resistance test. The rate (wavelength 550 nm) was measured in the same manner as described above, and the reduction rate of the transmittance by the moisture resistance test was determined. In addition, the decreasing rate of the transmittance was calculated from the formula {1- (transmittance after the moisture resistance test / transmittance before the test)} × 100 (%). In the present specification, when the calculated decrease rate of the transmittance decrease is 1% or less, the moisture resistance is good (◯), and when the decrease rate exceeds 1%, the moisture resistance is poor (x). The evaluation results are shown in Tables 1 and 2.

The glass powders A to H all had a softening point in the range of 570 to 590 ° C. Moreover, the linear expansion coefficient became in the range of 11-12 ppm / degreeC. Further, the glass powders A to H and P had good moisture resistance. Moreover, it turned out that A and EH are the glass which moisture resistance improved more. In addition, although the total value of the content of BaO and CaO exceeds 30 mass% and the content of SiO ₂ which is a glass skeleton forming component is increased, P is improved in moisture resistance. The softening point is as high as 689 ° C. When the softening point is high, the phosphor is liable to be deactivated, and thus is not preferable as the glass powder used in the present invention.

Glass powder I has a composition close to that of A to D except that the content of BaO, CaO, and SrO is small, but it has poor moisture resistance. Further, the glass powder J are compared with I, reduce the B ₂ O ₃ tends to lower the moisture resistance, a composition with increased ZnO tends to improve the moisture resistance, the improvement of moisture resistance as compared with I However, when compared with A to H and P, the improvement in moisture resistance was insufficient. From the above, it was shown that BaO, CaO, and SrO are effective for improving the moisture resistance.

  The glass powder L has a composition close to that of A to D except that MgO is used as an alkaline earth metal component, but the moisture resistance is remarkably lowered. Further, the glass powder M had a composition in which the BaO content and the MgO content were increased from the L content, but the moisture resistance was not improved. From the above, it was found that the moisture resistance of the composition containing MgO is greatly reduced.

Glass powder N is a composition with increased B ₂ O ₃ than I, the moisture resistance was confirmed that the deteriorated Increasing B ₂ O _3. Further, the glass powder O has a BaO content of more than 30% by mass and relatively close to E to H, but the improvement in moisture resistance is insufficient. From the above, it was found that when the content of BaO is too large, the moisture resistance is lowered.

2: Production and evaluation of phosphor-dispersed glass Whether the glass powder obtained above can actually be used for phosphor-dispersed glass was examined by producing phosphor-dispersed glass by the following method. First, various phosphors were added to and mixed with the glass powders (A to J, L to P) in Tables 1 and 2 to obtain mixed powders (oxide phosphor content; 4 vol%, nitride phosphor content; 4 vol%). At this time, for glass powder A, a mixed powder obtained by mixing 16 vol% of sulfide phosphor was also produced. Next, a button-shaped preform having a diameter of 10 mm and a thickness of 2 mm was produced by pressure molding with a mold. Next, it sintered by heating for 30 minutes in air | atmosphere, and obtained the sintered compact. After polishing the obtained sintered body to a thickness of 1 mm for a sintered body using an oxide phosphor and a nitride phosphor, and to a thickness of 0.5 mm for a sintered body using a sulfide phosphor, The luminescence was evaluated and the results are shown in Table 3. Glass powders I, J, and L to P are comparative examples.

<Measurement method of external quantum efficiency>
A sintered body using Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor (emission center 555 nm) as the oxide phosphor and (SrCa) AlSiN ₃ : Eu ²⁺ phosphor (emission center wavelength 610 nm) as the nitride phosphor is The external quantum efficiency was measured by the following method.

  The measurement is performed using the fluorescence spectrophotometer (FP-6500 manufactured by JASCO Corporation) to which an integrating sphere (ILF-533 manufactured by JASCO Corporation) is connected, and the integrated intensity of the excitation light spectrum entering the integrating sphere is obtained from A and the sample. With the integrated intensity of the emitted fluorescence spectrum as C, the external quantum efficiency was determined as C / A. It can be said that the higher the internal quantum efficiency and the external quantum efficiency, the higher the light emission efficiency.

<Evaluation of light emission of sulfide phosphor>
As the sulfide phosphor, a (Zn, Cd) S: Cu phosphor (emission center: 850 nm) was used. Since the phosphor cannot obtain the external quantum efficiency with the above-described apparatus, the emission of the phosphor was simply examined by the following method.

  First, blue LED light (emission peak wavelength: 445 nm) lit at a current of 300 mA was incident on one side of the phosphor-dispersed glass obtained by the above method. Next, light emitted from the opposite surface was made incident into a calibrated integrating sphere and taken into a small spectroscope (HR-4000 manufactured by Ocean Optics) through an optical fiber to obtain an emission spectrum (energy distribution curve). The integrated intensity of the fluorescence spectrum emitted from the sample was calculated to obtain the radiant flux of the fluorescence spectrum.

  Next, for comparison, a button-shaped molded body having a diameter of 10 mm and a thickness of 0.5 mm in which 16 vol% of (Zn, Cd) S: Cu phosphor was dispersed in silicone was produced. The obtained molded body was subjected to the above-described emission spectrum measurement in the same manner as the phosphor-dispersed glass. As a result, the radiant flux of the sintered body using the glass powder A is 9.65 uW, the radiant flux of the molded body using silicone is 7.31 uW, and the radiant flux of the sintered body with respect to the molded body is 132%. It became.

  From the above, in any of the examples and comparative examples, the external quantum efficiency of the oxide phosphor was 72% or more, indicating excellent luminous efficiency. The nitride phosphor was 47 to 49% in the examples, and 15 to 48% in the comparative example. Of the comparative examples, I, L, and N that showed luminous efficiency equivalent to the examples are insufficient for the purpose of the present invention because the glass powder lacks moisture resistance. In addition, I, L, and N are those in which the external quantum efficiency of the nitride phosphor is slightly lowered and the moisture resistance is poor. P is a glass powder with good moisture resistance, but the nitride phosphor was deactivated due to its high softening point.

  Further, the radiant flux increased in the phosphor-dispersed glass of the present invention as compared with the sulfide phosphor dispersed in silicone. The radiant flux is a value representing the radiant energy that passes through a certain surface per unit time, and the value decreases when the phosphor is deactivated. Thereby, it was found that the composition of the present invention does not deactivate the sulfide phosphor.

3: Evaluation of moisture resistance of phosphor-dispersed glass When a glass powder having good moisture resistance was used as the phosphor-dispersed glass, whether or not it actually showed good moisture resistance was examined below. Among the examples described above, a humidity resistance test is performed on the phosphor-dispersed glass in which the oxide phosphor is dispersed using the glass powder A and the phosphor-dispersed glass in which the nitride phosphor is dispersed using the glass powder A. Went.

  In the moisture resistance test, the obtained sintered body was left in a PCT (saturated pressurized steam test) at a temperature of 121 ° C. and a humidity of 100% for 96 hours, and the external quantum efficiency after the moisture resistance test was defined as above. In the same manner, the rate of decrease in external quantum efficiency by a moisture resistance test was determined. The reduction rate of the external quantum efficiency was calculated from the equation {1- (external quantum efficiency after the moisture resistance test / external quantum efficiency before the moisture resistance test)} × 100 (%). In the present specification, when the calculated decrease rate of the external quantum efficiency is 5% or less, the moisture resistance is considered good.

Further, the glass powder A, the above oxide phosphor or a nitride phosphor (respectively 4 vol%), and the inorganic filler (SiO 2; _2% by weight) and mixed powder by mixing, in a manner similar to that described above The mixed sintered body was sintered to produce a sintered body. The obtained sintered body was similarly evaluated for external quantum efficiency and moisture resistance. The above results are shown in Table 4.

From the above, it was found that the moisture resistance was good even when actually used as a phosphor-dispersed glass. Furthermore, it became clear that even the phosphor-dispersed glass using the filler does not impair the moisture resistance.

Claims (7)

In the phosphor-dispersed glass in which the phosphor is dispersed in the glass, the glass does not substantially contain Nb ₂ O ₅ and is in mass%.
The SiO ₂ 15~40%,
10 to 30% of B ₂ O ₃
1 to 35% of ZnO,
Al ₂ O ₃ 0-20%,
2 to 30% in total of at least one selected from the group consisting of BaO, CaO, and SrO,
0 to 1% MgO
5 to 35% in total of R ₂ O (at least one selected from the group consisting of Li ₂ O, Na ₂ O, and K ₂ O),
And a phosphor-dispersed glass characterized by containing a total of 0 to 15% of at least one selected from the group consisting of antimony oxide and tin oxide. The phosphor-dispersed glass according to claim 1, wherein the glass contains 1 to 30% by mass of BaO. The phosphor-dispersed glass according to claim 1 or 2, wherein the glass contains at least 0.1% by mass of antimony oxide and tin oxide. The phosphor-dispersed glass according to any one of claims 1 to 3, wherein the glass has a linear expansion coefficient of 6 to 13 ppm / ° C and a softening point of 670 ° C or less at 30 to 300 ° C. The phosphor particles are at least one selected from the group consisting of oxides, oxynitrides, nitrides, oxysulfides, sulfides, aluminate chlorides, halophosphates, fluorides, and YAG compounds. The phosphor-dispersed glass according to claim 1, wherein the phosphor-dispersed glass is provided. The phosphor-dispersed glass according to any one of claims 1 to 5, wherein the phosphor-dispersed glass contains an inorganic filler. A light emitting device comprising: the phosphor-dispersed glass according to claim 1; and an LED or an LD.