JP2009277997A - Mixed glass powder for coating light-emitting element, glass-coated light-emitting element, and glass-coated light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide mixed glass powder for coating a light-emitting element, which contains a phosphor and seals a semiconductor light-emitting element at ≤400°C to improve luminous efficiency after the sealing, and to provide a glass-coated light-emitting element and a glass-coated light-emitting device using the same. <P>SOLUTION: The glass powder for coating the light-emitting element that seals the light-emitting element contains: glass powder of ≤1% in relative particle amount of particles of ≤1 μm in particle diameter in the glass powder by laser diffraction type grading distribution measurement; and phosphor powder. Luminous efficiency, when the semiconductor light-emitting element operated with a current of 10 mA is sealed, is ≤2 times as large as that of a semiconductor light-emitting element operated with a current of 10 mA. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to glass, and in particular, to a glass powder of glass for coating a light emitting element, a glass coated light emitting element and a glass coated light emitting device coated using the same.

  In recent years, glass has been proposed as a member for covering a semiconductor light emitting element (for example, a light emitting diode). Generally, the sealing temperature with glass is as high as 500 ° C. or higher, and a low temperature (400 ° C. or lower) is required. Furthermore, it is also required that glass contains a phosphor so that desired light can be emitted. The following Patent Documents 1 and 2 disclose a glass containing a phosphor and having a sealing temperature (firing temperature) of 400 ° C. or lower. Patent Document 3 discloses a glass having a sealing temperature (firing temperature) of 400 ° C. or lower.

JP 2008-19421 A JP 2008-21868 A JP 2008-34802 A

  However, in any of Patent Documents 1 to 3, the luminous efficiency after sealing is equal to or less than the luminous efficiency before sealing.

  If it demonstrates in detail, patent document 1 will disclose the glass which contains a fluorescent substance in Examples 1-19 and 21-24, and Comparative Example 25, and whose baking temperature is 400 degrees C or less. As disclosed in paragraph 0074 of Patent Document 1, “light emission efficiency is the light emitted from the upper surface of the sample in a integrating sphere by placing the sample on a blue LED (wavelength 465 nm) operated at a current of 20 mA. Measure the energy distribution spectrum of ". That is, Patent Document 1 does not actually seal the glass. In addition, even if the luminous efficiency of Patent Document 1 is simply mounted, the luminous efficiency before and after mounting is equivalent, and there is no disclosure or suggestion that the luminous efficiency is improved by the glass after mounting. Therefore, the glass of Patent Document 1 does not have a function of improving luminous efficiency.

  Next, Patent Document 2 discloses a glass containing a phosphor and having a baking temperature of 400 ° C. or lower in Example 7 and Comparative Example 8. As described in Patent Document 2, paragraph No. 0058, “The luminous efficiency is that incident light having the wavelength shown in the table operated at a current of 20 mA is incident on one surface of the sample and emitted from the surface opposite to the incident surface. The emission spectrum of the obtained light is measured using a general-purpose fluorescence spectrum apparatus ". That is, since Patent Document 2 does not actually seal the glass, those skilled in the art do not know that the glass of Patent Document 2 improves the light emission efficiency.

  Next, Patent Document 3 discloses glasses having a firing temperature of 400 ° C. or lower in Examples 1 to 23 and Comparative Example 25. As described in paragraphs [0067] to [0069] of Patent Document 3, “the obtained glass powder was put into a mold to form a disk-shaped molded body to obtain a sealing material. A stop material was placed and heated to obtain a light-emitting element, and the luminous efficiency before sealing, after sealing, and after the weather resistance test was measured ". In Patent Document 3, glass is actually sealed as compared with other Patent Documents. However, as shown in Tables 1 to 4, the luminous efficiency after sealing is inferior to the luminous efficiency before sealing. Therefore, the glass of Patent Document 3 does not have a function of improving luminous efficiency. Moreover, the fluorescent substance is not contained.

  The mixed glass powder for covering a light-emitting element according to one embodiment of the present invention includes a glass powder having a relative particle amount of 1% or less of particles having a particle size of 1 μm or less in the glass powder, and a phosphor by laser diffraction particle size distribution measurement And a powder.

  The glass-coated light-emitting element of one embodiment of the present invention is a mixed glass powder containing phosphor powder and having a relative particle amount of 1% or less of particles having a particle diameter of 1 μm or less in the powder by laser diffraction particle size distribution measurement. It is characterized by being covered with the glass produced by using the glass.

  The glass-coated light-emitting device of one embodiment of the present invention includes a substrate, a light-emitting element mounted on the substrate, and a phosphor powder, and is a relative particle of particles having a particle size of 1 μm or less by laser diffraction particle size distribution measurement. It is characterized by comprising glass that covers the surface and side surfaces of the light emitting element by firing a mixed glass powder having an amount of 1% or less.

  ADVANTAGE OF THE INVENTION According to this invention, the semiconductor light-emitting device containing a fluorescent substance is sealed at 400 degrees C or less, The mixed glass powder for light-emitting device coating | cover which can improve the luminous efficiency after sealing, Glass coating using the same A light-emitting element and a glass-coated light-emitting device can be provided.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the figure, corresponding parts are indicated by corresponding reference numerals. The following embodiment is shown as an example, and various modifications can be made without departing from the spirit of the present invention.

  First, a glass-coated light-emitting device will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of the glass-coated light-emitting device of the present invention. The glass-coated light-emitting device of the present invention is electrically connected to the substrate 110, the wiring 110 formed on the substrate, the bump 120 electrically connected to the wiring 110, and the wiring 110 via the bump 120. A semiconductor light emitting element (for example, a light emitting diode) 130 and a glass 140 that is a covering member that covers the semiconductor light emitting element 130 are included.

  The substrate 100 is, for example, a rectangular alumina substrate or magnesia (MgO) substrate having a purity of 98.0 mass% to 99.5 mass% and a thickness of 0.5 mm to 1.2 mm. Note that the wiring 110 formed on the surface of the substrate 100 is a gold wiring manufactured using gold or silver paste.

The semiconductor light emitting device 130 includes a substrate, an LED, a plus electrode, and a minus electrode. The LED emits ultraviolet light or blue light having a wavelength of 360 to 480 nm, and is an LED having a quantum well structure (InGaN-based LED) having InGaN in which In is added to GaN as a light emitting layer. The substrate has a thermal expansion coefficient (α) of 70 × 10 ^{−7 to} 90 × 10 ⁻⁷ / ° C. Usually, a sapphire substrate having a thermal expansion coefficient (α) of about 80 × 10 ⁻⁷ / ° C. is used as the substrate.

  Next, the light emitting element coating glass of the present invention will be described.

  The light-emitting element coating glass powder (glass frit) of the present invention is obtained by melting a glass mixed raw material adjusted to have a desired composition to vitrify, and then pulverizing the glass.

  The pulverization operation of the light emitting device coating glass of the present invention is preferably performed by a dry method. When it is wet, OH groups adhere around the mixed particles. Therefore, after baking at 400 ° C. or less, the glass may be blackened. Air, helium, neon, argon, krypton xenon, fluorine, chlorine, bromine, Knox (NOx), sox (SOx), nitrogen, carbon monoxide, carbon dioxide, hydrogen, chlorine Alternatively, a mixed atmosphere of these gases may be employed. Furthermore, the pressure of these gases can be changed arbitrarily, and may be performed under atmospheric pressure, or may be performed under reduced pressure or under high pressure.

  The measurement of particle size distribution may be based on any principle, but it is a method that can measure each particle in a dispersed state, and the reproducibility of the measurement result is within 5%. It is suitable if it is difficult for individual differences due to handling to occur. For example, it is preferable to employ measurement by a laser diffraction measurement apparatus using a sample subjected to reduction operation. In the case of measurement of sintered raw materials, it is possible to substitute by measuring the particle size distribution by using an electron microscope, an observation device for various fine structures and an analysis device for the obtained image, etc. . The glass powder covering the light-emitting element of the present invention has a relative particle amount of 1 μm or less in the powder glass in a measurement using a laser diffraction particle size distribution analyzer (SALD-2100) manufactured by Shimadzu Corporation. % Or less. If it is 1% or more, the glass after sealing may become opaque. 1% or less is preferable and 0.1% or less is more preferable. Moreover, it is preferable that the relative particle amount of particles having a particle size of 45 μm or less in the powder glass is 10% or less. If it is 10% or more, the glass after sealing may become opaque depending on the process conditions. On the other hand, it is preferable that the glass powder covering the light emitting device of the present invention does not contain particles having a particle diameter of 250 μm or more in the glass powder. When particles of 250 μm or more are included, there is a possibility that the LED elements cannot be sealed uniformly.

  For the pulverization operation of the light emitting element coating glass of the present invention, any pulverization apparatus can be used as long as a desired mixing effect can be realized. For example, pulverization can be performed using any of a ball mill, a medium stirring mill, and an airflow pulverizer. It should be noted that excessively fine pulverization may cause generation of a large number of particles having an unfavorable particle size, and therefore it is important not to further pulverize after the desired particle size is reached. For this purpose, for example, it is preferable to perform an operation of taking out the desired particles using a sieve having a mesh that does not allow the desired particles to pass therethrough or a cyclone classifier.

  Here, the ball mill uses ceramics or natural ore as a medium called a ball, and the medium is repeatedly collided with the surface of the object to be crushed, so that the object to be crushed is gradually crushed and pulverized. It is a processing device. As this ball mill, there are a rolling ball mill (a ball mill in a narrow sense) that performs grinding in the most general cylindrical or conical containers, a vibration mill that performs fine grinding by applying fine vibration to the ball, It includes a medium planetary mill that has been accelerated to improve the grinding efficiency. The production method of the present invention can also be realized by adjusting the oxygen concentration, nitrogen concentration, carbon dioxide concentration and the like in the environment in which this apparatus operates. The media agitation mill, like the ball mill, causes the media to collide with the object to be crushed, but it provides a complex motion for the media by providing a disk or wing-like rotating body in the container that contains the media. It is a pulverizing apparatus that enables efficient pulverization. As the medium agitation mill, generally, a stamp mill type, an aniler mill type, a tower mill type, a sand grinder mill type, an attritor mill type, or the like can be used. Furthermore, the airflow type pulverizer is a pulverization apparatus that employs a method of pulverizing by forcibly colliding the object to be pulverized by a high-speed jet airflow or the like, and is suitable for adjusting powder with uniform particle size. In particular, when the apparatus is used, a desired pulverization environment can be realized by setting the atmosphere of the jet stream itself to be adjusted so as to be maintained in a high humidity environment. In addition, the above-described pulverizing apparatus may be used alone, or connected to other pulverizing apparatuses or the like to be used as a continuous plant facility. It is possible to select appropriately according to the kind, amount, usage, etc. of the dressing material.

The glass for coating the light emitting device of the present invention can be coated at 400 ° C. or lower. For example, in the case of a SnO—P ₂ O ₅ glass composition, the glass transition temperature (Tg) is in the range of 285 ° C. to 300 ° C.

The thermal expansion coefficient (α) of the glass composition of the present invention is preferably 130 × 10 ⁻⁷ / ° C. or less, and more preferably 128 × 10 ⁻⁷ / ° C. or less. When the coefficient of thermal expansion (α) exceeds 130 × 10 ⁻⁷ / ° C., after the light emitting device is coated with glass, the portion of the glass in contact with the light emitting device is cooled in the process of cooling to room temperature or in the subsequent process. There is a risk of cracking as a starting point. For example, in the case of a SnO—P ₂ O ₅ glass composition, the thermal expansion coefficient (α) is preferably 110 × 10 ⁻⁷ / ° C. or higher, and 115 × 10 ⁻⁷ / ° C. or higher. More preferred. For example, in the case of a SnO—P ₂ O ₅ glass composition, when the thermal expansion coefficient (α) is less than 110 × 10 ⁻⁷ / ° C., the glass transition temperature (Tg) increases.

The glass that covers the light emitting device of the present invention contains at least one of TeO ₂ , B ₂ O ₃ , SiO _{2, and} P ₂ O ₅ as a network former. Specifically, TeO ₂ —ZnO, B ₂ O ₃ —Bi ₂ O ₃ , SiO ₂ —Bi ₂ O ₃ , SiO ₂ —ZnO, B ₂ O ₃ —ZnO, P ₂ O ₅ — One selected from ZnO-based and P ₂ O ₅ —SnO-based, or two or more composite-based glasses selected from them.

  The glass of the present invention contains an inorganic phosphor powder. Here, examples of the inorganic phosphor powder include oxides, nitrides, oxynitrides, sulfides, oxysulfides, halides, aluminate chlorides, and halophosphates.

  Among the above-described inorganic phosphors, those having an excitation band at a wavelength of 300 to 500 nm and having an emission peak at a wavelength of 380 to 780 nm, particularly those emitting light in blue, green and red are preferably used.

Examples of phosphors that emit blue fluorescence when irradiated with excitation light in the ultraviolet region with a wavelength of 300 to 440 nm include Sr ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ , (Sr, Ba) MgAl ₁₀ O ₁₇ : Eu ²⁺ , (Sr , Ba) ₃ MgSi ₂ O ₈ : Eu ²⁺ .

As phosphors that emit green fluorescence when irradiated with excitation light in the ultraviolet region with a wavelength of 300 to 440 nm, SrAl ₂ O ₄ : Eu ²⁺ , SrGa ₂ S ₄ : Eu ²⁺ , SrBaSiO ₄ : Eu ²⁺ , CdS: In, CaS : Ce ³⁺ , (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce ³⁺ , Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce ³⁺ , SrSiOn: Eu ²⁺ , ZnS: Al ³⁺ , Cu ⁺ , CaS: Sn ²⁺ , CaS: Sn ²⁺ , F, CaSO ₄ : Ce ³⁺ , Mn ²⁺ , LiAlO ₂ : Mn ²⁺ , BaMgAl ₁₀ O ₁₇ : Eu ²⁺ , Mn ²⁺ , ZnS ^{_{: Cu +, Cl -, Ca}} 3 WO 6: U, Ca 3 SiO 4 Cl 2: Eu 2+, Sr X Ba y Cl z Al ₂ O _{4-z / 2} : Ce ³⁺ , Mn ²⁺ (X: 0.2, Y: 0.7, Z: 1.1), Ba ₂ MgSi ₂ O ₇ : Eu ²⁺ , Ba ₂ SiO ₄ : Eu ²⁺ Ba ₂ Li ₂ Si ₂ O ₇ : Eu ²⁺ , ZnO: S, ZnO: Zn, Ca ₂ Ba ₃ (PO ₄ ) ₃ Cl: Eu ²⁺ , BaAl ₂ O ₄ : Eu ²⁺ .

Examples of phosphors that emit green fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm include SrAl ₂ O ₄ : Eu ²⁺ , SrGa ₂ S ₄ : Eu ²⁺ , (Ba, Sr) ₂ SiO ₄ : Eu ²⁺ , CdS: In, CaS: Ce ³⁺ , (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce ³⁺ , Ca ₃ Sc ₂ SiO ₃ O ₁₂ : There are Ce ³⁺ , CaSc ₂ O ₄ : Ce ³⁺ , and SrSiO _N : Eu ²⁺ .

Examples of phosphors that emit yellow fluorescence when irradiated with excitation light in the ultraviolet region with a wavelength of 300 to 440 nm include ZnS: Eu ²⁺ , Ba ₅ (PO ₄ ) ₃ Cl: U, Sr ₃ WO ₆ : U, CaGa ₂ S _4. : Eu ²⁺ , SrSO ₄ : Eu ²⁺ , Mn ²⁺ , ZnS: P, ZnS: P ³⁻ , Cl ⁻ ZnS: Mn ²⁺ .

As a phosphor that emits yellow fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ , (Y, Gd) ₃ (Al, Ga) ₅ O _{12 : Ce3 +, Ba 5 (PO} 4) 3 Cl: U, CaGa 2 S 4: there is ^{Eu 2+.}

Examples of phosphors that emit red fluorescence when irradiated with excitation light in the ultraviolet range of 300 to 440 nm include CaS: Yb ²⁺ , Cl, Gd ₃ Ga ₄ O ₁₂ : Cr ³⁺ , CaGa ₂ S ₄ : Mn ²⁺ , Na ( Mg, Mn) ₂ LiSi ₄ O ₁₀ F ₂ : Mn, ZnS: Sn ²⁺ , Y ₃ Al ₅ O ₁₂ : Cr ³⁺ , SrB ₈ O ₁₃ : Sm ²⁺ , MgSr ₃ Si ₂ O ₈ : Eu ²⁺ , Mn ²⁺ , α-SrO · 3B ₂ O ₃ : Sm ²⁺ , ZnS—CdS, ZnSe: Cu ⁺ , Cl, ZnGa ₂ S ₄ : Mn ²⁺ , ZnO: Bi ³⁺ , BaS: Au, K, ZnS: Pb ²⁺ , ZnS: Sn _{^{2+, Li +, ZnS: Pb}} , Cu, CaTiO 3: Pr 3+, CaTiO 3: Eu 3+, Y 2 O 3: Eu 3+, (Y, Gd) 2 _{^{3: Eu 3+, CaS: Pb}} 2+, Mn 2+, YPO 4: Eu 3+, Ca 2 MgSi 2 O 7: Eu 2+, Mn 2+, Y (P, V) O 4: Eu 3+, Y 2 O 2 S: Eu ³⁺ , SrAl ₄ O ₇ : Eu ³⁺ , CaYAlO ₄ : Eu ³⁺ , LaO ₂ S: Eu ³⁺ , LiW ₂ O ₈ : Eu ³⁺ , Sm ³⁺ , (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ There are Cl ₂ : Eu ²⁺ , Mn ²⁺ , Ba ₃ MgSiO ₂ O ₈ : Eu ²⁺ , Mn ²⁺ .

As phosphors that emit red fluorescence when irradiated with blue excitation light having a wavelength of 440 to 480 nm, ZnS: Mn ²⁺ , Te ²⁺ , Mg ₂ TiO ₄ : Mn ⁴⁺ , K ₂ SiF ₆ : Mn ⁴⁺ , SrS: Eu ²⁺ Na _1.23 K _0.42 Eu _0.12 TiSi ₄ O ₁₁ , Na _1.23 K _0.42 Eu _0.12 TiSi ₅ O ₁₃ : Eu ³⁺ , CdS: In, Te, CaAlSiN ₃ : Eu ²⁺ , There are (Sr, Ca) AlSiN ₃ : Eu ²⁺ , CaSiN ₃ : Eu ²⁺ , (Ca, Sr) ₂ Si ₅ N ₈ : Eu ²⁺ , Eu ₂ W ₂ O ₇ .

  A plurality of inorganic phosphor powders may be mixed and used in accordance with the wavelength range of the excitation light and the color to be emitted. For example, in order to obtain white light by irradiating ultraviolet excitation light, phosphors emitting blue, green, and red fluorescence may be mixed and used.

  Some of the above inorganic phosphor powders react with glass by heating during sintering and cause abnormal reactions such as foaming and discoloration. Become. However, even such inorganic phosphor powders can be used by optimizing the firing temperature and glass composition.

  The resin supports the glass powder and filler in the coating film after screen printing. Specific examples include ethyl cellulose, nitrocellulose, acrylic resin, vinyl acetate, butyral resin, melamine resin, alkyd resin, and rosin resin. There are ethyl cellulose and nitrocellulose as main agents. Butyral resin, melamine resin, alkyd resin, and rosin resin are used as additives for improving the strength of the coating film.

  The inorganic fluorescent material preferably has a thermal conductivity at 25 ° C. of 10 W / m · K or more (preferably 15 W / m · K or more, more preferably 20 W / m · K or more). By doing so, when the thermal conductivity of the inorganic material substrate is increased, the heat dissipation effect is increased.

  The total light transmittance of the glass covering the light emitting device of the present invention is preferably 80% or more. If it is 80 or less, the light extraction efficiency may deteriorate.

  Examples 1 to 6 are examples, and examples 7 to 8 are comparative examples.

(Example 1)
P ₂ O ₅ —SnO system composed of 30% P ₂ O ₅ , 60% SnO, 6% ZnO, 3% CaO and 1% B ₂ O ₃ in terms of mole percent on an oxide basis Glass powder was used. To this glass powder, 2% by mass of YAG-based phosphor powder ((Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ ) was added to prepare a phosphor-containing glass powder.

  Next, the produced phosphor-containing glass powder was fired to produce a glass plate, and the produced glass plate was stirred using a medium stirring mill. The stirred glass powder was passed through a sieve having a mesh having a diameter of 250 μm, and the glass powder having a particle size of 250 μm or more was stopped again. Thus, a glass powder having a particle size of 45 to 74 μm was obtained.

  Next, connection bumps are formed on a magnesia substrate (thickness: 1 mm, size: 7 mm × 5 mm) on which a gold wiring pattern is formed, and a blue LED (trade name: E1C60-0B011-03, wavelength: 460 nm) manufactured by Toyoda Gosei. The LED was flip-chip mounted on a magnesia substrate. And in order to suppress the bubble which generate | occur | produces in the interface of glass and a board | substrate, the alumina substrate which mounted LED was put into the electric furnace (IR heating apparatus), and it heat-processed at 600 degreeC. The temperature rising rate was set to 300 ° C./min, the holding time at 600 ° C. was set to 2 minutes, and the temperature decreasing rate was set to 300 ° C./min. Note that bubbles generated at the interface between the glass and the substrate are generated when the glass is softened in response to organic contaminants attached to the substrate surface. The generated bubbles refract light emitted from the semiconductor light emitting element, which may reduce the luminance of the light emitting device or change the light distribution of the light emitting device. Therefore, before covering the LED with glass, the substrate on which the LED is mounted is heated to reduce organic contaminants adhering to the substrate surface, thereby suppressing the generation of bubbles. According to numerous experiments, the heating temperature is preferably around 600 ° C. The heating time is preferably around 2 minutes considering the influence of heat on the LED.

  5 g of glass powder was placed on the flip-chip mounted LED. Then, it put into the electric furnace, heated up to 360 degreeC at the speed | rate of 100 degreeC / min, and hold | maintained at the temperature for 3 minutes. Here, when the glass which coat | covers LED was observed visually, the bubble was not recognized by the surface vicinity.

  When a DC voltage was applied to the glass-coated light emitting device thus obtained, light emission was confirmed.

(Example 2)
The same as Example 1 except that 5% by mass of YAG phosphor powder ((Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ ) was added to produce a phosphor-containing glass powder.

(Example 3)
A phosphor-containing glass powder was prepared by adding 5% by mass of a phosphor (CaAlSiN ₃ : Eu ²⁺ ) instead of the YAG phosphor powder ((Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ ). Same as Example 1.

(Example 4)
Instead of YAG-based phosphor powder ((Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ ), 5% by mass of phosphor ((Sr, Ca) AlSiN ₃ : Eu ²⁺ ) is added to add phosphor-containing glass powder. The same as Example 1 except that was manufactured.

(Example 5)
Instead of YAG-based phosphor powder ((Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ ), 5% by mass of phosphor ((Ba, Sr) ₂ SiO ₄ : Eu ²⁺ ) is added to add phosphor-containing glass. Same as Example 1 except that the powder was made.

(Example 6)
YAG phosphor powder _{((Y, Gd) 3 Al} 5 O 12: Ce 3+) in place of the phosphor: to prepare a phosphor-containing glass powder (CaSc ₂ O ₄ ^{Ce 3+)} was added to 5 mass% Otherwise, the same as Example 1.

(Example 7)
The same as Example 1 except that a glass powder not containing YAG phosphor powder ((Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ ) was produced.

(Example 8)
The light-emitting device is not sealed with glass.

(Measurement result)
For the glass-coated light-emitting device produced as described above, the luminous efficiency (unit: lm / W), ratio (unit:%), external quantum efficiency (unit:%), chromaticity coordinates (X, Y), and color tone are determined. It measured by the following measuring methods.

  Luminous efficiency: Using an external quantum efficiency measurement device (Hamamatsu Photonics), measure the energy distribution spectrum of the light emitted from the light emitting device to which the current was applied, and multiply the obtained spectrum by the standard relative luminous sensitivity. The luminous flux was calculated and the total luminous flux obtained was divided by the power of the light source. The operating current was 10 mA.

    Ratio: The luminous efficiency of Examples 1 to 7 divided by the luminous efficiency of Example 8.

External quantum efficiency: Using an external quantum efficiency measuring device (manufactured by Hamamatsu Photonics), the ratio (N ₂ / N ₁ ) of the number of electrons N ₁ injected into the light emitting element and the number of photons N ₂ emitted to the outside (N ₂ / N ₁ ) It was measured. The operating current was 10 mA.

    Chromaticity coordinates: The spectrum was measured in the same manner as the luminous efficiency, and the chromaticity coordinates were read. The operating current was 10 mA.

    Transparency: The glass was visually observed, and the clear was marked with ◯.

  The results are shown in Table 1.

  As can be seen from Table 1, it was found that the external quantum efficiency was improved more than before sealing, and the luminous efficiency was doubled or more.

  In addition to the processing described above, the following processing may be performed.

(1) Surface treatment of glass frit During firing, coloring and / or foaming of glass may occur due to reaction between glass frits or at the interface between the frit and the phosphor. There is a concern that coloring or the like deteriorates the transmittance of the vitreous portion of the fired body and lowers the luminous efficiency. In the present invention, coloring and / or foaming is suppressed by controlling the pulverization conditions and the particle diameter, but there may be cases where methods such as modifying or coating the surface of the frit are also effective. For example, according to experiments by the inventors, it has been confirmed that coloring can be suppressed even by coating with TEOS.

(2) Phosphor surface treatment In addition to the above-described treatment (1), a method such as modifying or coating the surface of the phosphor may be applied. For example, it is considered that coloring can be suppressed even by coating with TEOS.

(3) Surface treatment of phosphor When the phosphor is a nitride or oxynitride, N ₂ or NOx may be generated from the phosphor surface by an oxidation reaction when fired in the atmosphere. If the glass is all oxide-based, most ions are oxide ions. Therefore, the glass is fired in an environment surrounded by a large number of oxide ions, and the oxidation reaction on the phosphor surface may be promoted. In that case, there is a concern that foaming may occur on the surface, the transmittance of the vitreous portion is deteriorated, and the luminous efficiency is lowered. In order to suppress such a foaming phenomenon, it is conceivable that the phosphor is heated before mixing with the frit to cause an oxidation reaction only on the surface, and no oxidation reaction occurs after mixing with the frit. Further, there may be cases where methods such as modifying or coating the surface of the frit are also effective.

(4) Inhibition of crystallization of glass At the time of firing, crystallization of the glass may occur due to the phosphor becoming crystal nuclei or / and reaction at the interface between the frit or between the frit and the phosphor. There is a concern that crystallization deteriorates the transmittance of the vitreous portion of the fired body and lowers the light emission efficiency. In addition, the firing temperature may increase. Therefore, it is conceivable that a method such as modifying or coating the surface of the phosphor is also effective for suppressing crystallization.

  The glass for coating an optical element of the present invention can be used for sealing LED elements used for backlight light sources for liquid crystal panels, general illumination, automobile headlights, and the like.

It is sectional drawing of the glass-coated light-emitting device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Substrate 130 Light emitting element 140 Glass containing phosphor powder

Claims (8)

A glass powder for covering a light emitting element capable of sealing the light emitting element,
A mixture for coating a light-emitting element, comprising: a glass powder having a relative particle amount of 1% or less of particles having a particle diameter of 1 μm or less in the glass powder, and a phosphor powder by laser diffraction particle size distribution measurement; Glass powder.   2. The light emitting device coating according to claim 1, wherein the light emitting efficiency when the light emitting device operated at a current of 10 mA is sealed is at least twice as high as that of the light emitting device operated at a current of 10 mA. Mixed glass powder for use. The glass for covering a light-emitting element according to claim 1, wherein the glass powder contains at least one of TeO ₂ , B ₂ O ₃ , SiO _2, or P ₂ O ₅ as a network former. Powder. The glass powder includes TeO ₂ —ZnO, B ₂ O ₃ —Bi ₂ O ₃ , SiO ₂ —Bi ₂ O ₃ , SiO ₂ —ZnO, B ₂ O ₃ —ZnO, P ₂ O ₅ —. 4. The light-emitting element coating mixture according to claim 1, wherein the mixture is selected from ZnO-based, P ₂ O ₅ —SnO-based, or two or more composite glasses selected from them. Glass powder.   It is characterized in that it is coated with glass prepared using a mixed glass powder containing phosphor powder and having a relative particle amount of 1% or less of particles having a particle size of 1 μm or less in the powder by laser diffraction particle size distribution measurement. A glass-coated light emitting device.   The glass-coated light emitting device according to claim 5, wherein the total light transmittance of the glass is 80% or more. The glass-coated light emitting device according to claim 5 or 6, wherein the glass has an expansion coefficient of 70 x ^{10-7 to} 125 x ^10-7 / ° C. A substrate,
A light emitting device mounted on the substrate;
Glass that covers the surface and side surfaces of the light-emitting element by firing a mixed glass powder containing phosphor powder and having a relative particle amount of 1% or less of particles having a particle size of 1 μm or less by laser diffraction particle size distribution measurement A glass-covered light-emitting device comprising:

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