JP5483795B2 - Luminescent color conversion material and luminescent color conversion member - Google Patents

Description

  The present invention relates to a luminescent color conversion material and a luminescent color conversion member obtained by firing the same.

  In recent years, white LEDs are expected to be applied to lighting applications as next-generation light sources that replace incandescent bulbs and fluorescent lamps.

  In the LED element that converts the wavelength using a phosphor, the phosphor powder is mixed and molded in a mold resin made of an organic binder resin that seals the light emitting surface of the LED chip, and part or all of the light emission of the LED chip is performed. Absorbed and converted to the desired wavelength.

  However, there is a problem that the molding resin constituting the LED element is deteriorated by high-power short-wavelength light in the blue to ultraviolet region and causes discoloration.

To solve the above problems, Patent Document _1, SnO 2 _-P 2 _{O 5} based _glass, TeO 2 -ZnO-based _{glass, Bi 2 O 3 -B 2 O} 3 based phosphor in a lead-free low-melting glass A method for dispersing the LED chip and covering the LED chip is disclosed.

However, _SnO 2 _-P 2 _{O 5} -based glass disclosed in Patent Document 1 has a problem of poor weather resistance. Further, TeO ₂ —ZnO-based glass has a problem that it absorbs light and converts it into heat because the glass itself is colored yellow. Bi ₂ O ₃ —B ₂ O ₃ -based glass has a problem that the appearance reacts with the phosphor and the appearance is blackened.
JP 2005-11933 A

  An object of the present invention is to provide a luminescent color conversion material that can be used as a luminescent color conversion member that is chemically stable and has little phosphor deterioration, and a luminescent color conversion member obtained by firing the luminescent color conversion material.

The luminescent color conversion material of the present invention is a luminescent color conversion material comprising an oxide glass powder and a phosphor powder having an emission peak in the visible range, and the oxide glass powder has a softening point of 650 ° C. or lower. In addition, it is characterized by being made of SiO ₂ —TiO ₂ —Nb ₂ O ₅ —R ₂ O (R is Li, Na, K) -based glass substantially not containing PbO.

  The luminescent color conversion material of the present invention comprises an oxide glass powder and a phosphor powder, and the luminescent color conversion member obtained by firing the luminescent color conversion material of the present invention has a phosphor dispersed in the glass. ing. For this reason, it is chemically stable and discoloration can be suppressed even when exposed to high output light for a long period of time.

The oxide glass powder in the present invention is made of SiO ₂ —TiO ₂ —Nb ₂ O ₅ —R ₂ O (R is Li, Na, K) -based glass substantially free of PbO. Since this oxide glass powder contains TiO ₂ and Nb ₂ O ₅ , it is excellent in weather resistance, particularly moisture resistance, and can improve the chemical stability of the luminescent color conversion member. Further, R _{2 O} content in oxide glass powder is preferably not more than 30 wt%. By the R 2 _O content is 30 wt% or less, it is possible to lower the softening point of the oxide glass powder without reducing weather resistance. A more preferable range of the R ₂ O content is 5 to 30% by mass.

  The oxide glass powder in the present invention does not substantially contain PbO, and the content of PbO is preferably 200 ppm or less.

  The softening point of the oxide glass powder in the present invention is 650 ° C. or less. By setting the softening point of the oxide glass powder to 650 ° C. or less, a luminescent color conversion member with little deterioration of the phosphor can be obtained. When the softening point exceeds 650 ° C., the phosphor is extremely deteriorated, which is not preferable. The softening point is more preferably 630 ° C. or lower. The lower limit value of the softening point is not particularly limited, but is generally 350 ° C. or higher.

Oxide glass powder in the present invention, by mass _{percentage, SiO 2: 20~50%, Li} 2 O: 0~10%, Na 2 O: 0~15%, K 2 O: 0~20%, Li 2 O + Na ₂ O + K ₂ O: 1-30%, B ₂ O ₃ : 1-20%, MgO: 0-10%, BaO: 0-15%, CaO: 0-20%, SrO: 0-20%, Al _{2 O 3: 0~20%, ZnO} : 0~15%, TiO 2: 0.01~20%, Nb 2 O 5: 0.01~20%, La 2 O 3: 0~15%, TiO 2 + Nb ₂ O ₅ + La ₂ O ₃ : It is preferable to contain 1 to 30%.

  The reasons for prescribing the content of each glass component are as follows.

SiO ₂ is a component constituting the skeleton of glass. When the content is less than 20% by mass, chemical durability tends to deteriorate. On the other hand, if it exceeds 50% by mass, the sintering (firing) temperature becomes high, and the phosphor tends to deteriorate. A more preferable range of SiO ₂ is 25 to 45%.

B ₂ O ₃ is a component that significantly lowers the melting property by lowering the melting temperature of the glass. When the content is less than 1% by mass, it is difficult to obtain the effect. On the other hand, when it exceeds 20 mass%, chemical durability tends to deteriorate. A more preferable range of B ₂ O ₃ is 6 to 15%.

  MgO is a component that improves the meltability by lowering the melting temperature of the glass. When the content exceeds 10% by mass, chemical durability tends to deteriorate. A more preferable range of MgO is 0 to 5%.

  CaO is a component that improves the meltability by lowering the melting temperature of the glass. When the content is more than 20% by mass, chemical durability tends to deteriorate. A more preferable range of CaO is 0 to 15%.

  SrO is a component that improves the meltability by lowering the melting temperature of the glass. When the content is more than 20% by mass, chemical durability tends to deteriorate. A more preferable range of SrO is 0 to 5%.

  BaO is a component that improves the meltability by lowering the melting temperature of the glass and suppresses the reaction with the phosphor. When the content is more than 15% by mass, chemical durability tends to deteriorate. A more preferable range of BaO is 6 to 12%.

Al ₂ O ₃ is a component that improves chemical durability. If the content exceeds 20% by mass, the softening point of the glass tends to increase. A more preferable range of Al ₂ O ₃ is 0 to 15%.

  ZnO is a component that improves the meltability by lowering the melting temperature of the glass. When the content exceeds 15% by mass, the softening point of the glass tends to increase. A more preferable range of ZnO is 1 to 7%.

Li ₂ O has the greatest effect of lowering the softening point among alkali metal components. Its content is 0-10%, preferably 1-9%, more preferably 1.5-7%. When Li ₂ O exceeds 10%, devitrification tends to occur. Further, the alkali elution amount increases and the weather resistance decreases.

Na ₂ O is a component that lowers the softening point. Its content is 0-15%, preferably 3-13%. When Na ₂ O exceeds 15%, the alkali elution amount increases and the weather resistance decreases.

K ₂ O has the effect of lowering the softening point, but the alkali elution amount increases and the weather resistance decreases. For this reason, the content of K ₂ O is limited to 0 to 20%, preferably 1 to 18%.

In order to suppress an increase in softening point and a decrease in weather resistance, the total amount (R ₂ O) of Li ₂ O, Na ₂ O, and K ₂ O, which are alkali metal oxides, is set to 1 to 30%. Is desirable.

TiO ₂ is a component that improves weather resistance. Its content is 0.01-20%, preferably 5-18%. When TiO ₂ exceeds 20%, crystals having TiO ₂ as a nucleus are likely to precipitate, and devitrification increases. On the other hand, if it is less than 0.01%, the weather resistance is remarkably lowered.

Nb ₂ O ₅ is a component that enhances the weather resistance while suppressing the precipitation of crystals due to TiO ₂ . Its content is 0.01-20%, preferably 3-17%. If nb ₂ O ₅ is more than _20%, crystals are likely to precipitate formed by the TiO 2 _-Nb 2 _{O 5-,} devitrification increases. On the other hand, if it is less than 0.01%, the effect of suppressing the precipitation of crystals due to TiO ₂ is reduced, and the weather resistance is significantly reduced.

La ₂ O ₃ is a component that improves weather resistance. Its content is 0-15%, preferably 1-15%. When La ₂ O ₃ exceeds 15%, crystals having La ₂ O ₃ as a nucleus are likely to precipitate, and devitrification increases.

Incidentally, in order to suppress the reduction in the weather _resistance, it is desirable to TiO 2, _Nb 2 _{O 5,} and the total amount of _La 2 _{O 3 1~30%.}

In addition to the above components, various components can be added as long as the gist of the present invention is not impaired. For example, Sb ₂ O ₃ , P ₂ O ₅ , Ta ₂ O ₅ , Gd ₂ O ₃ , WO ₃ , Bi ₂ O ₃ , ZrO or the like may be added.

The phosphor powder in the present invention is not particularly limited as long as it has an emission peak in the visible range. In the present invention, the visible region indicates 380 to 780 nm. Examples of such phosphors include YAG compounds, oxides, aluminate chlorides, nitrides, oxynitrides, sulfides, rare earth oxysulfides, halophosphates, and the like. A YAG phosphor is particularly preferably used because it is stable even when mixed with glass and heated to a high temperature. Phosphors such as aluminate chlorides, nitrides, oxynitrides, sulfides, rare earth oxysulfides, and halophosphates react with the glass by heating during sintering, causing abnormal reactions such as foaming and discoloration. It tends to occur, and the degree becomes more remarkable as the sintering temperature is higher. When such a phosphor is used, it can be used by optimizing the firing temperature and the glass composition. Specifically, by reducing the content of SiO _{2 in} the glass or increasing the content of R ₂ O, ZnO, B ₂ O ₃ to lower the softening point of the glass, What is necessary is just to reduce a calcination temperature.

  The luminous efficiency (lm / W) of the luminescent color conversion member varies depending on the type and content of phosphor particles dispersed in the glass, the thickness of the luminescent color conversion member, and the like. The phosphor content and the thickness of the luminescent color conversion member may be adjusted so as to optimize the luminous efficiency, but if the phosphor is too much, it becomes difficult to sinter or the porosity increases, Problems arise such that the excitation light is not easily irradiated onto the phosphor efficiently, and the mechanical strength of the luminescent color conversion member is likely to decrease. On the other hand, when the amount is too small, it becomes difficult to emit light sufficiently. Therefore, the mixing ratio (oxide glass powder: phosphor powder) of the oxide glass powder and the phosphor powder in the luminescent color conversion material is in the range of 99.99: 0.01 to 70:30 by mass ratio. Is more preferable, and 99.95: 0.05 to 80:20 is more preferable, and 99.92: 0.08 to 85:15 is particularly preferable.

  The luminescent color conversion member of the present invention is obtained by firing the luminescent color conversion material of the present invention.

  The firing atmosphere may be fired in the air. However, when obtaining a denser sintered body or reducing the reaction between the glass and the phosphor, the atmosphere is reduced or vacuum, or nitrogen or argon is used. Firing in an inert gas atmosphere is preferred.

  The firing temperature is preferably in the range of 400 to 750 ° C. When the firing temperature is higher than 750 ° C., the phosphor may be deteriorated, or the glass and the phosphor may react with each other, and the light emission efficiency may be significantly reduced. On the other hand, when the firing temperature is lower than 400 ° C., the porosity of the sintered body increases, and the light transmittance may decrease.

  The porosity of the luminescent color conversion member of the present invention is preferably 10% or less in order to obtain a luminescent color conversion member with high luminous efficiency. When the porosity is higher than 10%, the light scattering becomes strong, the amount of light passing therethrough is reduced, and the light emission efficiency tends to be lowered. On the other hand, when the porosity is larger than 10%, the mechanical strength of the luminescent color conversion member tends to be remarkably lowered. A more preferable range of the porosity is 8% or less. In the present specification, the porosity means a value obtained by the formula of (1−actual density / theoretical density) × 100 (%) based on the actual density and the theoretical density measured by the Archimedes method.

  The form of the light emission color conversion material when the light emission color conversion material of the present invention is baked to obtain the light emission color conversion member is not particularly limited. For example, the powder of the light emission color conversion material is pressed into a desired shape. It may be a molded body, a paste, or a green sheet.

  When used in the form of a paste, it is preferable to form a paste using a binder, a solvent, and the like together with a luminescent color conversion material composed of glass powder and phosphor powder. The proportion of the luminescent color conversion material in the entire paste is generally 30 to 90% by mass.

  A binder is a component which increases the film | membrane intensity | strength after drying and provides a softness | flexibility, and the content is about 0.1-20 mass% in general. Examples of the binder include polybutyl methacrylate, polyvinyl butyral, polymethyl methacrylate, polyethyl methacrylate, ethyl cellulose, nitrocellulose and the like, and these can be used alone or in combination.

  The solvent is used to paste the material, and the content is generally about 10 to 50% by mass. Examples of the solvent include terpineol, isoamyl acetate, toluene, methyl ethyl ketone, diethylene glycol monobutyl ether acetate, 2,2,4-trimethyl-1,3 pentadiol monoisobutyrate, and these may be used alone or in combination. Can do.

  The paste can be prepared by preparing a luminescent color conversion material, a binder, a solvent, and the like and kneading them at a predetermined ratio.

  In order to form a luminescent color conversion member on an inorganic material base material using such a paste, an inorganic material base material having a thermal expansion coefficient comparable to that of the luminescent color conversion member is prepared. A predetermined light emitting color conversion member is formed by applying a paste on the top using a screen printing method, a batch coating method, or the like, forming a coating layer having a predetermined film thickness, and then drying and baking at about 400 to 750 ° C. Can be formed.

  When the luminescent color conversion material of the present invention is used in the form of a green sheet, the green sheet is made into a green sheet using a binder, a plasticizer, a solvent, etc. together with a luminescent color conversion material composed of glass powder and phosphor powder. .

  As for the ratio of the luminescent color conversion material which occupies in a green sheet, about 50-80 mass% is common.

  As the binder and the solvent, the same binder and solvent as those used for the preparation of the paste can be used. The mixing ratio of the binder is generally about 0.1 to 30% by mass, and the mixing ratio of the solvent is generally about 1 to 40% by mass.

  The plasticizer is a component that controls the drying speed and imparts flexibility to the dried film, and the content thereof is generally about 0 to 10% by mass. Examples of the plasticizer include dibutyl phthalate, butyl benzyl phthalate, dioctyl phthalate, diisooctyl phthalate, dicapryl phthalate, and dibutyl phthalate, and these can be used alone or in combination.

  As a general method for producing a green sheet, the above-described luminescent color conversion material, binder, plasticizer, and the like are prepared, and a solvent is added to these to form a slurry, and this slurry is converted into polyethylene terephthalate (PET) by a doctor blade method. ) Or the like on a film. After the sheet is molded, it is dried to remove the organic solvent and the like to obtain a green sheet.

  In order to form a luminescent color conversion member on an inorganic material substrate using the green sheet obtained as described above, the green sheet is laminated on the inorganic material substrate, and the coating layer is formed by thermocompression bonding. After forming, the luminescent color conversion member can be obtained by firing in the same manner as in the case of the paste described above.

  When the powder of the luminescent color conversion material of the present invention is pressure-molded to form a luminescent color conversion member, 0-5% by mass of a resin binder is added to the luminescent color conversion material composed of glass powder and phosphor powder, and gold Press molding with a mold to prepare a preform. Subsequently, after removing the binder from the preform at a temperature of 300 ° C. or lower, it is fired in the same manner as the paste and the green sheet described above to obtain a light emitting color conversion member.

  In addition, as the resin binder, it is desirable to use a resin having a decomposition end temperature of 300 ° C. or lower, and examples thereof include nitrocellulose, polyisobutyl acrylate, polyethyl carbonate, and the like. These can be used alone or in combination.

  Examples of the luminescent color conversion member of the present invention include those that convert light having a wavelength of 360 to 500 nm into visible light. The conversion characteristics can be variously adjusted depending on the type of phosphor used.

  According to the present invention, it is possible to provide a light emitting color conversion member that is chemically stable and has little phosphor deterioration.

  Hereinafter, the present invention will be specifically described by way of examples.

(Sample Nos. 1 to 16)
First, an oxide glass powder was prepared. Each glass component was weighed and mixed so as to have the composition shown in Table 1 and Table 2, and this mixture was melted and vitrified at a melting temperature shown in the table for 1 hour in a platinum crucible and formed into a film. The film-like glass was pulverized by a ball mill and then classified by passing through a 325 mesh sieve to obtain an oxide glass powder. About the obtained oxide glass powder, the softening point temperature was calculated | required with the differential thermal analyzer, and the result was shown in Table 1 and Table 2.

  Next, the obtained oxide glass powder and the phosphor powder are mixed so as to have a blending ratio shown in the table, and 5% by mass of a resin binder (polyethyl carbonate) is added thereto and mixed, A button-shaped preform having a diameter of 1 cm was produced by pressure molding with a mold. The preform was fired at the sintering temperature shown in Table 1 and then processed to obtain a disk-like light emitting color conversion member having a diameter of 8 mm and a thickness of 1 mm.

  About the obtained luminescent color conversion member, the luminescence spectrum was measured and luminous efficiency was calculated | required by calculation.

  The emission spectrum is shown in Sample No. For Nos. 1 to 8, light having an excitation wavelength of 400 nm is incident on one side of the sample. For 9 to 16, light having an excitation wavelength of 460 nm was incident on one surface of the sample, and light emitted from the surface opposite to the surface was measured using a general-purpose emission spectrum measuring device. Luminous efficiency was calculated by calculating the total luminous flux using an integrating sphere, multiplying by standard relative luminous sensitivity, and dividing by the power of the light source. The luminous efficiency is shown in Tables 1 and 2.

In Table 1, Sample No. 1, 3, 4, 5, 7 and 8 are examples according to the present invention. 2 and 6 are comparative examples in which the softening point of the oxide glass powder exceeds 650 ° C. Sample No. No. 2 does not contain Nb ₂ O ₅ in the oxide glass powder. No. 6 does not contain TiO ₂ in the oxide glass powder.

  As is apparent from the results shown in Table 1, sample No. Nos. 1, 3, 4, 5, 7 and 8 show high luminous efficiency, but sample Nos. Of comparative examples using glass whose softening point exceeds 650 ° C. In 2 and 6, high luminous efficiency is not obtained.

In Table 2, sample No. Examples 9 to 15 are examples according to the present invention. No. 16 is a comparative example in which the softening point of the oxide glass powder exceeds 650 ° C. Sample No. No. 16 does not contain Nb ₂ O ₅ in the oxide glass powder.

  As is apparent from the results shown in Table 2, the sample Nos. Of the examples according to the present invention were used. Nos. 9 to 15 show high luminous efficiency, but sample Nos. Of comparative examples using glass whose softening point exceeds 650 ° C. In No. 16, high luminous efficiency was not obtained. Sample No. The luminous efficiency of 10 was a usable level, but the luminous efficiency was slightly lower than the other examples because of the large proportion of phosphor powder.

(Sample No. 17-32)
In the same manner as in the above examples, each glass component was mixed so as to have the composition shown in Table 3 and Table 4 to prepare an oxide glass powder, and the obtained oxide glass powder and the phosphor powder shown in the table Were mixed at a blending ratio shown in the table to prepare a preformed body in the same manner as in the above Example, and this was fired to obtain a light emitting color conversion member.

  The luminous efficiency of each of the obtained luminescent color conversion members was measured in the same manner as described above, and a moisture resistance test was performed. Sample No. For Nos. 17 to 25, light having an excitation wavelength of 400 nm was used as sample no. For Nos. 26 to 32, light having an excitation wavelength of 460 nm was incident on one side of the sample, and luminous efficiency was determined. The moisture resistance test was performed by leaving the luminescent color conversion member in a high temperature and high humidity tank at a humidity of 85% and a temperature of 85 ° C. for 100 hours. Luminous efficiency after the moisture resistance test was measured in the same manner as described above, and the reduction rate of the luminous efficiency by the moisture resistance test was determined. The rate of decrease in luminous efficiency was calculated from the formula: (1-luminous efficiency after moisture resistance test / luminous efficiency before moisture resistance test) x 100 (%). Tables 3 and 4 show the luminous efficiency before the moisture resistance test, the luminous efficiency after the moisture resistance test, and the rate of decrease in luminous efficiency.

  In Table 3, sample no. 17, 19, 20, 21, 24, and 25 are examples according to the present invention. Reference numerals 18, 22 and 23 are comparative examples.

Each sample of the comparative example has a softening point of 650 ° C. or lower. In Nos. 18, 22 and 23, Nb ₂ O ₅ is not contained in the oxide glass powder. No. 22 does not contain TiO ₂ in the oxide glass powder. Sample No. No. 18 is a glass powder containing Al ₂ O ₃ and B ₂ O ₃ as main components. 22 is a glass powder containing Bi ₂ O ₃ as a main component. 23 is a glass powder containing TeO ₂ as a main component.

  As is clear from the results shown in Table 3, sample No. 18, 22, and 23, the light emission efficiency was significantly reduced by the moisture resistance test. In 17, 19, 20, 21, 24, and 25, the rate of decrease in luminous efficiency is reduced, it has good moisture resistance, is chemically stable, and the phosphor is less deteriorated.

  In Table 4, Sample No. 26, 27, 28, 29 and 31 are examples according to the present invention. 30 and 32 are comparative examples.

Each sample of the comparative example has a softening point of 650 ° C. or lower. In Nos. 30 and 32, Nb ₂ O ₅ is not contained in the oxide glass powder. No. 30 does not contain TiO ₂ in the oxide glass powder. Sample No. 30 is a glass powder containing Bi ₂ O ₃ as a main component. 32 is a glass powder containing TeO ₂ as a main component.

  As is clear from the results shown in Table 4, sample No. In samples 30 and 32, the light emission efficiency was significantly reduced by the moisture resistance test. In 26, 27, 28, 29 and 31, the rate of decrease in light emission efficiency is reduced, it has good moisture resistance, is chemically stable, and the phosphor is less deteriorated.

  From the above, it can be seen that by using the luminescent color conversion material according to the present invention, a luminescent color conversion member that is chemically stable and has little phosphor deterioration is obtained.

Claims (3)

A luminescent color conversion member obtained by firing a luminescent color conversion material comprising an oxide glass powder and a phosphor powder having an emission peak in the visible range,
From the SiO ₂ —TiO ₂ —Nb ₂ O ₅ —R ₂ O (R is Li, Na, K) -based glass having a softening point of 650 ° C. or less and substantially free of PbO. Become
The oxide glass powder, by mass _{percentage, SiO 2: 20~50%, Li} 2 O: 0~10%, Na 2 O: 0~15%, K 2 O: 0~20%, Li 2 O + Na 2 _{O + K 2 O: 1~30%} , B 2 O 3: 1~20%, MgO: 0~10%, BaO: 0~15%, CaO: 0~20%, SrO: 0~20%, Al 2 O _{3: 0~20%, ZnO: 0~15} %, TiO 2: 0.01~20%, Nb 2 O 5: 0.01~20%, La 2 O 3: 0~15%, TiO 2 + Nb 2 Luminescent color conversion member characterized by containing O ₅ + La ₂ O ₃ : 1 to 30%. The mixing ratio of the oxide glass powder and the phosphor powder (oxide glass powder: phosphor powder) is in the range of 99.99: 0.01 to 70:30 by mass ratio. The luminescent color conversion member according to 1 . The luminescent color conversion member according to claim 1 or 2 , wherein light having a wavelength of 360 to 500 nm is converted into visible light.