JP2012158494A - Glass composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bismuth-based glass composition not containing lead, having a low glass transition point (Tg) and high refractive index, and having high fluorescent characteristic and reliability in which glass and a phosphore do not react with each other even after a coating work.SOLUTION: The glass composition which contains BiOand has a glass transition point (Tg) of ≤500°C is BiO-BO-ZnO-based glass. The glass composition also contains each component in mol% display based on oxides, of 5-50% BO, 5-90% BiOand 5-70% ZnO, wherein a value of the ratio ZnO/BOis ≥0.2, and a value of the ratio ZnO/BiOis ≥0.2 in mol% display based on oxides.

Description

  The present invention relates to a glass used for coating a light emitting element (light emitting diode, organic EL, etc.) and a glass-coated light emitting element and / or a glass-coated light emitting device coated with the glass.

  Conventionally, a resin such as an epoxy resin, a silicone resin, or a fluororesin has been mainly used as a member for covering the light emitting element. However, it has been pointed out that the above members are susceptible to deterioration due to heat generation of the element, light and / or moisture in the environment, and have a short life. In addition, the light emitting efficiency is insufficient, and the conventional light emitting device is difficult to be applied to general lighting and lighting such as a headlight for automobiles that require high luminance and long life. Thus, glass has been attracting attention as a covering member.

For example, Patent Document 1 discloses disclosure of B ₂ O ₃ —SiO ₂ —ZnO glass, B ₂ O ₃ —SiO ₂ —PbO glass, and B ₂ O ₃ —P ₂ O ₅ —ZnO glass. .
However, the above document does not describe a specific composition and is not practical. In addition, lead has a large impact on the environment, and manufacturing of glass containing PbO components and waste treatment require water quality inspection of wastewater and waste separation, etc. Therefore, a sealing material containing no lead is desired.

Patent Document 2 discloses P ₂ O ₅ —Al ₂ O ₃ —ZnO-based glass and B ₂ O ₃ —SiO ₂ —ZnO—Nb ₂ O ₅ -based glass.
However, P ₂ O ₅ —Al ₂ O ₃ —ZnO-based glass generally has low chemical durability and has problems in water resistance and weather resistance. Further, when an operation such as heat treatment is performed to cover the LED chip or the like, the glass and the phosphor react with each other, causing problems such as deterioration of fluorescent characteristics and discoloration.
In B ₂ O ₃ —SiO ₂ —ZnO—Nb ₂ O ₅ glass, it is difficult to lower the glass transition point (Tg). In order to make Tg 500 ° C. or less, it is necessary to contain a large amount of an alkali metal component, but at the same time, chemical durability is deteriorated, so that water resistance and weather resistance are deteriorated, as well as fluorescence. Since it becomes easy to react with the body, it is not suitable for covering the light emitting element.
Furthermore, for glass in such applications, if the glass transition point (Tg) is high, the working temperature at the time of coating becomes high, causing damage to the element and deterioration of the phosphor. In addition, when the refractive index is not sufficiently high, the light extraction efficiency from the element is deteriorated, and it is difficult to increase the luminance. Therefore, it is not suitable for coating a light emitting element with high luminance and long life.
In the glass described in the above document, since it is necessary to contain a large amount of an alkali metal component or the like in order to lower the glass transition point (Tg), the content of the component contributing to the high refractive index is limited. Therefore, it is considered difficult to achieve a Tg lower than 500 ° C. and a refractive index of 1.6 or more for a light beam having a wavelength of 588 nm with the glass of the above document.

Patent Document 3 discloses P ₂ O ₅ —SnO—ZnO-based glass.
However, glass containing a large amount of tin needs to be manufactured in a reducing atmosphere, which increases the manufacturing cost. Furthermore, since the valence change is likely to occur during heating, it reacts with surrounding oxygen and phosphor during the coating operation, causing crystallization and discoloration.

JP 2006-310375 A JP 2010-278474 A JP 2008-300536 A

  The present invention has been made in view of the problems as described above, does not contain lead, has a low glass transition point (Tg) and a high refractive index, and does not react with glass even after coating operation, and has high fluorescence characteristics. And a reliable glass composition.

In order to solve the above-mentioned problems, the present inventors appropriately adjust the contents of B ₂ O ₃ , Bi ₂ O ₃ , and ZnO to achieve a low glass transition point (Tg), a high refractive index, and a phosphor. The present inventors have found that a glass composition having characteristics that are difficult to react with can be obtained, and have completed the present invention.
Specifically, the present invention provides the following.

(1) A glass composition containing Bi ₂ O ₃ and having a glass transition point (Tg) of 500 ° C. or lower.
_{(2) Bi 2 O 3,} B 2 O 3, the glass composition according to ZnO required to contain (1).
(3) 5 to 50% B ₂ O ₃ in terms of mol% based on oxide
5-90% Bi ₂ O ₃
5-70% ZnO
(1) or the glass composition as described in (2) containing each component of.
(4) It is characterized in that the value of the ratio of ZnO / B ₂ O ₃ is 0.2 or more and the value of the ratio of ZnO / Bi ₂ O ₃ is 0.2 or more in terms of mol% on the basis of oxide ( The glass composition according to any one of 1) to (3).
(5) 0 to 15% SiO ₂ in terms of mol% based on oxide
0-15% of _P 2 _{O 5}
0 to 20% Rn ₂ O (where R is one or more selected from the group consisting of Li, Na, K, and Cs)
0-20% BaO
The glass composition in any one of (1)-(4) containing each component of these.
(6) 0 to 20% MgO in terms of mol% based on oxide
0-20% CaO
0-20% SrO
0-15% TiO ₂
0-15% ZrO ₂
0-15% Nb ₂ O ₅
0-15% SnO
0-15% WO ₃
0-40% TeO ₂
0-30% Ln ₂ O ₃ (where Ln is one or more selected from the group consisting of Y, La, Ce, Gd, Dy, Yb, Lu)
The glass composition in any one of (1)-(5) containing each component of.
(7) The temperature difference (ΔT) between the crystallization temperature (Tx) and the glass transition point (Tg) is 80 ° C. or more, and the refractive index with respect to light having a wavelength of 588 nm is 1.6 or more. The glass composition in any one.
(8) The glass composition according to any one of (1) to (7), wherein an average linear thermal expansion coefficient at 30 ° C. to 300 ° C. is 150 × 10 ⁻⁷ / ° C. or less.
(9) A glass for covering a light-emitting element, comprising the glass composition according to any one of (1) to (8).
(10) A phosphor composite material comprising the light emitting element coating glass and phosphor of (9).
(11) The phosphor composite material according to (10), wherein glass and phosphor are mixed at a mass ratio (glass: phosphor) of 99.999: 0.001 to 70:30 and fired.
(12) The phosphor composite material according to (11), wherein 0 to 80% by mass of the glass composition is substituted with a resin.
(13) A phosphor composite member obtained by firing at 600 ° C. or lower.
(14) A phosphor composite member comprising the light emitting element coating glass and phosphor of (9).
(15) The phosphor composite member according to (14), wherein 0 to 80% by mass of the glass composition is substituted with a resin.
(16) The phosphor composite member according to (12), wherein light having a wavelength of 250 to 600 nm is converted into visible light.

  According to the present invention, the above problems can be solved without including lead, and the following effects can be obtained.

  According to the present invention, a glass having a glass transition point (Tg) of 500 ° C. or lower can be obtained.

  According to the present invention, a glass having a temperature difference (ΔT) between the crystallization temperature (Tx) and the glass transition point (Tg) of 80 ° C. or more and a refractive index of 1.6 or more at a wavelength of 588 nm can be obtained. .

According to this invention, the glass whose average linear thermal expansion coefficient in 30 to 300 degreeC is 150x10 < ^-7 > / degrees C or less can be obtained.

  Since the glass of the present invention is difficult to react with the phosphor even at high temperatures, a composite material in which the phosphor is dispersed in the glass can be produced by mixing the glass and the phosphor and performing heating or the like.

  Since the glass of the present invention has a high refractive index, it is suitable for production of a light-emitting element with high light extraction efficiency and high brightness.

  Next, specific embodiments of the glass composition of the present invention will be described.

(Glass component)
The composition range of each component which comprises the glass composition of this invention is described below. Each component is expressed in mol%. In the present specification, all glass compositions represented by mol% are represented by mol% based on oxides. Here, the “oxide standard” is the sum of the generated oxides when it is assumed that oxides, nitrates, etc. used as raw materials for the glass constituents of the present invention are all decomposed and changed to oxides when melted. Is a composition in which each component contained in the glass is expressed as 100 mol%.

The Bi ₂ O ₃ component plays the role of a glass-forming oxide, greatly contributes to the improvement of the stability of the glass, and is an indispensable component particularly for realizing a low glass transition point (Tg) and a high refractive index. However, if the content is too small, it will be difficult to achieve the desired physical properties described above, and if it is contained excessively, the glass stability will be impaired, it will become difficult to vitrify, and the chemical durability will tend to deteriorate, or quartz will be melted during melting. The crucible is eroded violently, causing foreign matter to enter. Therefore, the upper limit of Bi ₂ O ₃ content is preferably 90%, more preferably 60%, and most preferably 40%. Further, the lower limit is preferably 5%, more preferably 16%, and most preferably 20%.

B ₂ O ₃ is a glass-forming oxide and is a useful component for obtaining a stable glass. When the content is small, it becomes difficult to vitrify, and it causes crystallization and discoloration due to heating by a covering operation when sealing the light emitting element or the like. On the other hand, if the amount is too large, there is a disadvantage that the chemical durability tends to deteriorate or the reaction with the phosphor easily occurs. In order to realize a light emitting device and / or a light emitting device having high brightness, high output, and long life without crystallization or reaction with a phosphor even in the covering step of the issuing device, the content of B ₂ O ₃ is 5% or more. More preferably, it is 10% or more, and most preferably 15% or more. Further, the upper limit of these contents is preferably 50%, more preferably 45%, and most preferably 36%.

  ZnO is an effective component for improving the glass stability and lowering the Tg, and is indispensable for maintaining the stability of the glass particularly during heat treatment. In the present invention, the content of ZnO strongly depends on the softness and devitrification properties of glass and the reactivity with phosphors during the stability of the glass and coating operations. Therefore, if the amount is too small, the object of the present invention Cannot be achieved. On the other hand, if the amount is too large, the stability of the glass is impaired and there is a disadvantage that it is difficult to vitrify. Therefore, the lower limit of the amount of ZnO is preferably 5%, more preferably 20%, and most preferably 40%. Further, the upper limit is preferably 70%, more preferably 60%, and most preferably 55%.

In the coating operation, discoloration and transmittance decrease due to crystallization of glass-forming oxide (eg; Bi ₂ O ₃ crystal, Bi ₂ O ₃ —B ₂ O ₃ crystal) and reaction between glass and phosphor. Sometimes. In order to maintain a stable glass without reacting with the phosphor, the ZnO / B ₂ O ₃ ratio expressed in mol% based on the oxide is preferably 0.2 or more, more preferably 1.2 or more, Most preferred is 1.8 or more.
Further, the ZnO / Bi ₂ O ₃ ratio is preferably 0.2 or more, more preferably 1.2 or more, and most preferably 1.8 or more.

The SiO ₂ component is a component capable of forming a glass skeleton, and is an optional component because it is a component that improves chemical durability.
However, if the amount is more than 15%, the glass is phase-separated and becomes easily devitrified, and the Tg becomes high, so that the coating operation at 600 ° C. or less becomes difficult. Therefore, the content of the SiO ₂ component is preferably 15% or less, more preferably 10% or less, and most preferably 6% or less.

The P ₂ O ₅ component is a component that forms a glass skeleton and is an optional component because it is a component that stabilizes the glass when added in a small amount. However, if the amount is more than 15%, the glass is phase-divided and is easily devitrified. Therefore, the content of the P ₂ O ₅ component is preferably 15% or less, more preferably 10% or less, and most preferably 6% or less.

_{Rn 2 O (R = Li,} Na, K, 1 or more selected from the group consisting of Cs) component suppressing foaming of the batch during glass melting, enhancing the meltability and stability of glass, further a glass Although it is a useful component that has a large effect in reducing Tg of the glass, if it is contained excessively, the chemical durability of the glass tends to deteriorate, and it becomes devitrified by treatment such as heating at the time of coating operation of the light emitting element and the like. Or react with phosphors. Therefore, the upper limit is preferably 20%, more preferably 10%, and most preferably 6%. It is more effective to use one or more of these components.

  BaO is an optional additive component that is effective in improving the meltability and stability of glass and lowering Tg, and is also effective in improving chemical durability. However, if the amount is too large, the glass stability is deteriorated. Accordingly, the upper limit of the content is preferably 20%, more preferably 15%, and most preferably 10%.

  RO (R is one or more selected from the group consisting of Mg, Ca and Sr) is effective in improving the melting and stability of glass, lowering Tg, and also improving chemical durability. Is an optional additive component. However, if the amount is too large, the glass stability is deteriorated. Therefore, the upper limit of the total content of these components is preferably 20%, more preferably 15%, and most preferably 5%.

The TiO ₂ , ZrO ₂ , and Nb ₂ O ₅ components are components that can be optionally added and are effective in improving chemical durability and increasing the refractive index. However, if the amount is too large, the meltability and stability of the glass are lowered and Tg is also greatly increased. Therefore, the upper limit of these components is preferably 15%, more preferably 10%, and most preferably 5%.

The TeO ₂ component is effective for improving the meltability and softening properties, lowering the Tg temperature and increasing the refractive index, and can be optionally added. However, if the content is too large, the stability of the glass also decreases. Therefore, the upper limit is preferably 40%, more preferably 20%, and most preferably 10%.

SnO and WO ₃ components are effective in improving meltability and softening characteristics, lowering Tg and increasing the refractive index, and can be added arbitrarily. However, if the content of these components is too large, the stability of the glass The nature is also reduced. Therefore, the upper limit of these components is preferably 15%, more preferably 10%, and most preferably 5%.

Ln ₂ O ₃ (one or more selected from the group consisting of Ln = Y, La, Ce, Gd, Dy, Yb, and Lu) is effective in improving chemical durability and increasing the refractive index. However, if the total content of one or more of these components is too large, not only the meltability and stability of the glass are lowered, but also the Tg is raised. Therefore, the upper limit of these components is preferably 30%, more preferably 20%, and most preferably 10%. In particular, when it is desired to sufficiently obtain the above effect, the lower limit is preferably 0.1%, more preferably 0.2%, and most preferably 0.3%. It is more effective to use one or more of these rare earth oxides simultaneously with one or more of the above-described TiO ₂ , ZrO ₂ , Nb ₂ O ₅ , SnO, WO ₃ , and TeO ₂ components.

The Sb ₂ O ₃ or As ₂ O ₃ component can be added for defoaming during glass melting, but up to 5% is sufficient. Therefore, it is preferably 5% or less, more preferably 3% or less, and most preferably not contained.

<About ingredients that should not be included>
Cd and Tl components can be contained for the purpose of lowering Tg. However, each component of Pb, Th, Cd, Tl, and Os tends to be refrained from being used as a harmful chemical material in recent years, so that not only the glass manufacturing process but also the processing process and the disposal after commercialization. Environmental measures are required. Therefore, it is preferable not to include substantially when importance is attached to environmental influences.

  Since the lead component needs to take measures for environmental measures when manufacturing, processing, and disposing glass, it should be contained if possible because the cost becomes high.

Since coloring components such as Fe ₂ O ₃ , Cr ₂ O ₃ , CuO, NiO, and MnO ₂ cause the phosphor composite material to be colored, it is preferable to suppress these components to a total amount of 1% or less. More preferably, it is 0.5% or less, Most preferably, it is 0.05% or less.

The light emitting element and / or the light emitting device can be obtained by setting the mixing ratio of the glass composition and the phosphor of the phosphor composite material of the present invention (glass: phosphor) to 99.999: 0.001 to 10:90 in mass ratio. Obtainable.
If the value of the above ratio is too large, the phosphor cannot be sufficiently covered with glass, and there is a disadvantage that the phosphor is not sufficiently deteriorated and the light extraction efficiency cannot be sufficiently obtained, and the value of the above ratio is too small. There is a disadvantage that a color change due to conversion of light having a wavelength of 250 to 600 nm into visible light cannot be sufficiently obtained. In the present invention, visible light refers to 380 nm to 780 nm.
If necessary, part of the glass may be replaced with resin. In that case, in the composite material, it is possible to seal at a lower temperature by replacing 0 to 80% by mass of the glass composition with a resin.

  The phosphor composite member can be produced by mixing the glass composition and the phosphor and performing a heat treatment at 600 ° C. or lower using an electric furnace or the like, but is not limited to this method. . For example, as a method for producing a phosphor composite member, there are a method of making a paste by mixing with an organic solvent and then softening the glass by heating or the like, a method of producing by laser irradiation, or the like. Further, there is a manufacturing method under reduced pressure or / and in a vacuum or a reducing atmosphere.

  When a phosphor composite material obtained by mixing glass composition powder and phosphor powder is used, unevenness after the phosphor composite member can be suppressed and the phosphor can be easily coated with the glass composition. The powder of the glass composition preferably has a relative particle amount of particles having a particle size of 1 μm or less of more than 1%, preferably 1.5% or more, and most preferably 2% or more.

By performing the coating operation of the phosphor composite material of the present invention at 600 ° C. or lower, a phosphor composite member can be obtained without damaging the device. More preferable is a coating operation at 550 ° C. or less, and further preferable is a coating operation at 520 ° C. or less.
Therefore, the upper limit of the glass transition point of the glass composition of the present invention is preferably 500 ° C., more preferably 480 ° C., and most preferably 450 ° C.

  The phosphor used for the phosphor composite material is not particularly limited as long as it has an emission peak in the visible light region. Such phosphors include oxides, nitrides, oxynitrides, chlorides, acid chlorides, sulfides, oxysulfides, halides, chalcogenides, aluminates, halophosphates, YAG compounds, etc. Is mentioned.

  In the present specification, the crystallization temperature (Tx) and the glass transition point (Tg) are measured by a differential thermal analyzer (DTA), and the temperature difference (ΔT) between Tx and Tg is less than 80 ° C. During the coating operation, the glass crystallizes, causing discoloration and scattering of light from the light emitting element. Therefore, ΔT is preferably 80 ° C. or higher, more preferably 110 ° C. or higher, and most preferably 150 ° C. or higher.

  When the refractive index of the glass composition and / or the phosphor composite material is high, light from the light-emitting element can be extracted efficiently, so that a light-emitting element and / or light-emitting device with high luminance can be obtained. Therefore, the refractive index with light having a wavelength of 588 nm is preferably 1.6 or more, more preferably 1.7 or more, and still more preferably 1.8 or more.

Conventionally, there are sapphire, GaN, and the like as materials used for light emitting elements, and their thermal expansion coefficients are about 75 × 10 ⁻⁷ / ° C. and 56 × 10 ⁻⁷ / ° C. (a axis), respectively. If the difference in coefficient of thermal expansion between the coating material and the material used for the light emitting element is large, it may cause cracking or breakage due to thermal strain. Therefore, the thermal expansion coefficient in the temperature range of 30 to 300 ° C. is preferably 150 × 10 ⁻⁷ / ° C. or less, more preferably 130 × 10 ⁻⁷ / ° C. or less, and further preferably 110 × 10 ⁻⁷ / ° C. or less. It is.

  The phosphor composite member of the present invention can convert light of 250 to 600 nm into visible light. “Conversion” as used herein refers to the fact that one or more phosphors absorb external light and emit fluorescence or / and phosphorescence, and the characteristic is to use a fluorescence spectrometer or the like. Can be confirmed.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example and a comparative example, this invention is not limited to a following example.

(Production of glass)
Silica sand, boric acid, dibasic ammonium phosphate, aluminum oxide, aluminum metaphosphate, lithium carbonate, sodium carbonate, primary phosphorus so that the glass has the composition ratio shown in Table 1 expressed in mol% based on oxide. Sodium carbonate, potassium carbonate, potassium dihydrogen phosphate, zinc oxide, zinc metaphosphate, magnesium oxide, calcium oxide, strontium carbonate, strontium nitrate, barium carbonate, barium nitrate, barium metaphosphate, titanium oxide, zirconium oxide, tellurium dioxide, Glass raw material batches such as bismuth oxide, tungsten oxide, tin oxide, lanthanum oxide, yttrium oxide, gadolinium oxide, niobium oxide, arsenous acid, and antimony pentoxide were prepared. The glass raw material batch was filled into an alumina crucible, a quartz crucible, a gold crucible, or a platinum crucible, and heated and melted at a temperature of 750 ° C. to 1400 ° C. for 30 minutes to 4 hours in an electric furnace. The molten glass was molded into a plate shape and slowly cooled.

(Measurement of glass)
About the produced glass, the glass transition point (Tg), crystallization temperature (Tx), the average linear thermal expansion coefficient in 30 to 300 degreeC, and the refractive index were measured. The results are shown in Tables 1-3.

(Glass transition point (Tg))
The glass transition point (Tg) and the crystallization temperature (Tx) were measured with a differential thermal analyzer (DTA) at a heating rate of 10 ° C./min. A sample in which a crystallization peak was not clearly observed was marked with “-” and evaluated as a stable glass that was difficult to crystallize.

(Coefficient of thermal expansion)
According to JOGIS (Japan Optical Glass Industry Association Standard) 16-2003 “Measuring Method of Average Linear Expansion Coefficient of Optical Glass Near Room Temperature”, the temperature range was changed from 30 ° C. to 300 ° C. and the average linear expansion The coefficient was measured. The measured average linear expansion coefficient (α) is shown in Table 1.

  About the refractive index [nd] in wavelength 588nm, it measured about the glass obtained by making slow cooling temperature-fall rate into -25 degrees C / hr.

(Phosphor sealing test)
The produced glass was pulverized with a ball mill or the like to obtain a powdery glass having an average particle size of about 5 μm.

Next, the produced glass powder and the phosphor powder were mixed to produce a phosphor composite material. The phosphor to be used is not particularly limited as long as it has a light emission peak in the visible light range, but in this example, a phosphor mainly containing Ce: Y ₃ Al ₅ O ₁₂ was used. . In this example, the weight ratio of mixing the glass and the phosphor was set to 99.95: 0.05.

  The obtained phosphor composite material was put in a mold and pressure-molded at 30 MPa to produce a molded body having a diameter of 20 mm and a thickness of 2 mm. The molded body was heat-treated at 550 ° C. for 1 hour to produce a phosphor composite member.

  The reaction between the glass and the phosphor was evaluated by observing whether the sample (phosphor composite member) obtained by heat treatment was colored. Each sample was visually observed, and the sample having the same color as the phosphor powder was marked with “◯”, and the sample colored with a color different from the phosphor powder was marked with “X”. The coloration of the sample in a color different from that of the phosphor powder indicates that the phosphor has deteriorated due to the reaction between the glass and the phosphor due to the heat during firing.

  As shown in Table 1, the glass of the example of the present invention has a glass transition point (Tg) of 458 to 475 ° C., and the difference (ΔT) between the crystallization peak (Tx) and the glass transition point (Tg). Is 162 ° C. or higher. In some examples, no clear crystallization peak was observed. Usually, the coating temperature is higher than Tg, and the larger the difference (ΔT) between Tg and Tx, the harder it is to crystallize during the coating operation and the glass can be sufficiently softened. That is, the glass of the present invention is hardly crystallized and can be said to be a glass suitable as a sealing material. Usually, since a light emitting element etc. will be damaged when it becomes higher than 600 degreeC, the coating | coated at 600 degrees C or less is preferable. Since the glass of the present invention has a relatively low Tg of 500 ° C. or lower, it can be coated by heat treatment or the like at 600 ° C. or lower, and can be said to be suitable for coating a light-emitting element.

  The glass of the example of the present invention has a refractive index (nd) at a wavelength of 588 nm of 1.85 to 1.87. Conventionally, a resin has been used as a sealing material for a light emitting element, and its refractive index was about 1.40 to 1.6. Therefore, the refractive index of the sealing material is lower than the refractive index of the light emitting part (for example, in LED, sapphire is used for the chip substrate of the light emitting element, and the refractive index is about 1.85), and light extraction is performed. The efficiency was low. Since the refractive index of the glass of the present invention is larger than 1.60, it can be expected to improve the light extraction efficiency, and it can be said that the glass is suitable as a sealing material for a light emitting element.

The glass of the example of the present invention has a thermal expansion coefficient (α) of 65.6 to 80.1 × 10 ⁻⁷ / ° C. in the temperature range of 30 to 300 ° C. It can be said that it is suitable as a stopping material.

  As shown in Table 1, the glass of the example of the present invention did not change color even when mixed with the phosphor and heat-treated at 550 ° C., and kept the same color as the phosphor powder. On the other hand, as shown in Table 4, the glass of the comparative example was discolored by heat treatment and discolored to a color different from the phosphor powder. The glass of the comparative example reacts with the phosphor by the coating operation and the phosphor deteriorates. However, the glass of the present invention does not change color after the phosphor composite member is produced, and the light having a wavelength of 250 to 600 nm is visible light. It has the function to convert to.

  As described above, the glass according to the present invention has a low glass transition point (Tg) and a large ΔT, so that the light emitting element can be coated at a low temperature. In addition, the light extraction efficiency from the light emitting element can be improved due to the high refractive index, and since the thermal expansion coefficient is close to that of the light emitting element material, cracks due to the difference in expansion coefficient are less likely to occur even after coating, and light from It is possible to manufacture a light emitting member with high brightness, high efficiency and high reliability without worrying about scattering. Furthermore, since lead is not contained, there is an advantage that no cost is required for environmental measures. In addition to the above effects, the glass according to the present invention has a function of converting light having a wavelength of 250 to 600 nm into visible light without being discolored even after the phosphor composite member is produced. In comparison with the above, it is possible to obtain a light emitting member that is excellent in heat resistance and ultraviolet resistance, has a long life, and has a light extraction effect with high efficiency.

Claims (16)

A glass composition containing Bi ₂ O ₃ and having a glass transition point (Tg) of 500 ° C. or lower. _{Bi 2 O 3, B 2 O} 3, the glass composition of claim 1, ZnO and containing mandatory. 5 to 50% B ₂ O ₃ in terms of mol% based on oxide
5-90% Bi ₂ O ₃
5-70% ZnO
The glass composition of Claim 1 or 2 containing each component of these. The value of the ZnO / B ₂ O ₃ ratio is 0.2 or more and the value of the ratio of ZnO / Bi ₂ O ₃ is 0.2 or more in terms of mol% on the oxide basis. 4. The glass composition according to any one of 3. 0 to 15% SiO ₂ in terms of mol% based on oxide
0-15% of _P 2 _{O 5}
0 to 20% Rn ₂ O (where R is one or more selected from Li, Na, K, and Cs)
0-20% BaO
The glass composition in any one of Claims 1-4 containing each component of these. 0 to 20% MgO in mole% based on oxide
0-20% CaO
0-20% SrO
0-15% TiO ₂
0-15% ZrO ₂
0-15% Nb ₂ O ₅
0-15% SnO
0-15% WO ₃
0-40% TeO ₂
0-30% Ln ₂ O ₃ (where Ln is Y, La, Ce, Gd, Dy, Yb, Lu)
The glass composition in any one of Claims 1-5 containing each component of these.   The temperature difference (ΔT) between the crystallization temperature (Tx) and the glass transition point (Tg) is 80 ° C. or higher, and the refractive index with respect to light having a wavelength of 588 nm is 1.6 or higher. Glass composition. The glass composition according to claim 1, wherein an average linear thermal expansion coefficient at 30 ° C. to 300 ° C. is 150 × 10 ⁻⁷ / ° C. or less.   A glass for covering a light emitting element, comprising the glass composition according to claim 1.   A phosphor composite material comprising the light emitting device coating glass of claim 9 and a phosphor.   The phosphor composite material according to claim 10, wherein the glass and the phosphor are mixed at a mass ratio (glass: phosphor) of 99.999: 0.001 to 70:30 and fired.   The phosphor composite material according to claim 11, wherein 0 to 80% by mass of the glass composition is substituted with a resin.   A phosphor composite member obtained by firing at 600 ° C. or lower.   A phosphor composite member comprising the light emitting element coating glass of claim 9 and a phosphor.   The phosphor composite member according to claim 14, wherein 0 to 80% by mass of the glass composition is substituted with a resin.   The phosphor composite member according to claim 12, wherein light having a wavelength of 250 to 600 nm is converted into visible light.