JP5190680B2 - Luminescent color conversion member - Google Patents

Description

  The present invention relates to a luminescent color conversion member for converting blue light from a blue light source, particularly a blue light emitting diode (LED) element, into white.

In recent years, white LEDs have attracted attention as high-efficiency and high-reliability white illumination light sources, and some of them are already in use as small-power small-sized light sources. In general, this type of LED is obtained by coating a blue LED element with a mixture of a yellow phosphor and a transparent resin.
2001-1119075 gazette

  However, since blue light has strong energy, it tends to deteriorate the resin. Therefore, when the white LED having such a structure is used for a long period of time, the resin is discolored and the color tone is changed. Recently, there has been a movement to develop a white illumination light source using a high-power LED element. In this case, a very strong blue light is irradiated to a limited part, so that the resin is significantly deteriorated and the emission color changes. It happens in a very short time. Further, since heat dissipation from the resin-molded element is poor, there is a problem that the temperature is likely to rise, and the color tone of the emission color shifts to the yellow side as the temperature rises.

  The present invention has been made in view of the above circumstances, and a luminescent color conversion member capable of obtaining a high-reliability, long-life white illumination light source even when a blue LED element, particularly a high-output blue LED element is used. The purpose is to provide.

The light emission color conversion member of the present invention is a light emission color conversion member for converting a part of blue light emitted from a blue light source into yellow light and combining it with the remaining blue light to obtain white light, which has a softening point. There higher than 500 ° C., the total amount of alkali metal oxides in the glass composition Ri Na inorganic phosphor is dispersed in the glass is less than 10%, and sintering the mixed powder of glass powder and an inorganic phosphor powder and wherein the Rukoto such from the body.

The material for the light emitting color conversion member of the present invention is a material for the light emitting color conversion member for converting part of the blue light emitted from the blue light source into yellow light and combining it with the remaining blue light to obtain white light. there are, softening point rather high than 500 ° C., the total amount of alkali metal oxide in the glass composition is characterized by comprising a mixture of glass powder and an inorganic phosphor powder is 10% or less.

The white illumination light source of the present invention has a blue light source and an emission color conversion member, converts a part of blue light emitted from the blue light source into yellow light, and combines with the remaining blue light to obtain white light. a white illumination light source, a softening point is higher than 500 ° C., Ri Na inorganic phosphor is dispersed in a glass total content of alkali metal oxides in the glass composition is 10% or less, and a glass powder and an inorganic characterized by using a Ru emitting color conversion member name of a sintered body of the mixed powder of the phosphor powder.

  Since the luminescent color conversion member of the present invention is mainly composed of chemically stable glass with high thermal conductivity, it does not change color even when exposed to high-power blue light for a long period of time, and the temperature rise of the device is small. So there is no discoloration of white light. Therefore, a highly reliable white illumination light source can be provided.

  The luminescent color conversion member of the present invention has a configuration in which an inorganic phosphor is dispersed in glass. More specifically, it consists of a sintered body of glass powder and inorganic phosphor powder.

As the inorganic phosphor, blue light emitted from a blue light source can be converted into yellowish light, for example, green-yellow (emission peak of about 550 nm), and can be used as long as it is generally available in the market. Some inorganic phosphors include sulfides, halophosphates, oxides, and the like. Oxide phosphors are stable when mixed with glass and heated to high temperatures, but phosphors such as sulfides and halophosphates react with the glass when heated during sintering, and abnormalities such as foaming and discoloration occur. Prone to reaction. The degree becomes more remarkable as the sintering temperature is higher. Therefore, it is preferable to use an oxide phosphor as the inorganic phosphor. The most suitable oxide phosphor includes Y ₃ Al ₅ O ₁₂ based phosphor such as (Y, Gd, Ce) ₃ Al ₅ O ₁₂ .

  Glasses are limited to those having a softening point above 500 ° C, preferably above 600 ° C. The reason is that glass having a softening point of 500 ° C. or less reacts with the phosphor to make the sintered body darker, resulting in a significant decrease in light emission efficiency and no light transmission. Moreover, chemical durability tends to deteriorate, and in a humid environment, the surface may be altered during use to reduce the transmittance and reduce the efficiency.

Glass having a thermal expansion coefficient exceeding 75 × 10 ⁻⁷ / ° C. is not preferable because cracks are easily formed in the sintered body due to thermal shock caused by repeated temperature rise during lighting and temperature drop during extinction. Therefore, a glass having a softening point of 500 ° C. or higher (particularly 600 ° C. or higher) and a thermal expansion coefficient of 75 × 10 ⁻⁷ / ° C. or lower (particularly 20 to 70 × 10 ⁻⁷ / ° C.) is preferable.

Further, when PbO or Bi ₂ O ₃ is contained in the glass composition, it is not preferable because it easily reacts with the phosphor to lower the brightness of the sintered body and lowers the light emission efficiency. Furthermore, it is important not to contain oxides that cause solarization or coloring elements that hinder the transmission of light, and not to contain such impurities. For example, if MnO, Fe ₂ O ₃ , CeO ₂ or the like is included in the composition, the glass is discolored by ultraviolet rays, so the inclusion of these components is not preferable. Moreover, when an alkali metal oxide is contained, resin used for adhesion | attachment of a member or a mold will be deteriorated, and adhesive strength will be reduced. Therefore, it is preferable that the above-mentioned components are not substantially contained in the glass composition. Specifically, it is desirable that PbO and Bi ₂ O ₃ are limited to 3% or less, MnO, Fe ₂ O ₃ , CeO _{2 and the} like are each limited to 1000 ppm or less, and the total amount of alkali metal oxides is limited to 10 % or less.

In addition, since the color tone of the sintered body varies depending on the composition system and the reactivity with the phosphor varies, it is necessary to select a glass composition to be used in consideration of various conditions. Furthermore, it is also important to determine the amount of phosphor added suitable for the glass composition and the thickness of the member. Suitable glasses in the present invention include B ₂ O ₃ —SiO ₂ glass, BaO—B ₂ O ₃ —SiO ₂ glass, ZnO—B ₂ O ₃ —SiO ₂ glass, and the like.

  When the thickness of the luminescent color conversion member of the present invention is less than 0.2 mm, it is difficult to obtain practical mechanical strength. For this reason, in applications where mechanical strength is required, it is preferable to have a thickness of 0.2 mm or more. In this case, the content of the inorganic phosphor is preferably 0.01 to 15% by volume. If the phosphor is less than 0.01% by volume, the yellow light is insufficient and hardly becomes white light. Conversely, if it exceeds 15%, the phosphor is shielded by the phosphor and the amount of blue light becomes too small, and the light is yellow. Shift to. In some cases, yellow light itself is also shielded, resulting in a significant reduction in luminous efficiency. The more preferable content of the phosphor is 0.05 to 10%, particularly 0.08 to 8% by volume, and further 0.1 to 3% by volume.

  Further, the luminescent color conversion member of the present invention can be used in various shapes such as a disk-shaped conversion member 10 as shown in FIG. 1 and a cylindrical cap-shaped conversion member 20 as shown in FIG. . In FIG. 1, 11 indicates an inorganic phosphor, and 12 indicates glass. Moreover, as shown in FIG. 3, it is also possible to use as a composite part which consists of the luminescent color conversion member 30 and the support member 40 which supports this. As the support member, members having various shapes can be adopted, and for example, a cylindrical member as shown in FIG. 3 can be used. The support member is made of a different material such as resin, ceramic, or metal. The material may be selected appropriately in consideration of conditions such as mechanical strength and expansion. Moreover, what is necessary is just to perform attachment of a conversion member by methods, such as fitting and adhesion | attachment.

  In the luminescent color conversion member of the present invention having the above configuration, since the phosphor is dispersed in the glass, a part of the incident blue light is converted into yellow light by the inorganic phosphor, and the remaining blue light is Transmits and scatters. Blue light is converted into white light by combining the converted yellow light and the transmitted and scattered blue light to synthesize a spectrum close to white light.

  In addition, when the scattering of the incident light is small, the white light obtained is strong and bright light, and when the scattering is large, the white light is soft.

  Further, as the thickness of the member increases, the brightness decreases and the light emission efficiency decreases. Furthermore, since the absolute amount of the phosphor increases and yellow light increases, the emission color easily shifts to the yellow side. On the other hand, if the member is thin, the light emission efficiency is increased, but the absolute amount of the phosphor is reduced and the yellow light is reduced, so that it tends to shift to the blue side. Therefore, in order to obtain white light efficiently, it is important to adjust the amount of the phosphor and the thickness of the member.

  Next, a method for producing the luminescent color conversion member of the present invention will be described.

First, a glass powder and an inorganic phosphor powder having the above characteristics are prepared. If it is desired to increase the scattering of the conversion member obtained here, a glass powder having a small particle size may be used, and if it is desired to reduce the scattering, a glass powder having a large particle size may be used. The preferred size range of the glass powder, the maximum particle diameter Dmax is 150μm or less (in particular 45～105Myuemu), and an average particle diameter _{D 50} is more than 2 [mu] m (in particular 10 to 20 [mu] m). In other words, when the maximum particle size of the glass powder exceeds 150 μm, transparent parts formed by coarse glass particles are scattered in the sintered body, and it becomes difficult to scatter light. , White light tends to be bluish. Also the average particle diameter D ₅₀ is less than 2 [mu] m, significantly reduces the permeability of the blue light to the sintered body is excessively scatter light, not only emission efficiency is lowered, the white light is yellowish It becomes easy to take on.

  Next, the inorganic phosphor powder and the glass powder are mixed to obtain a light emitting color conversion member material. What is necessary is just to adjust a mixing ratio in consideration of the thickness of the member to produce. That is, when the thickness of the member is thin, the ratio of the phosphor powder is set higher, and conversely, when it is thick, the ratio is set lower.

  Subsequently, a resin binder is added and pressure-molded to prepare a preform with a desired shape.

  Thereafter, the preform is fired, the resin binder is removed and sintered, and a luminescent color conversion member is obtained. What is necessary is just to attach the obtained conversion member to the support member prepared separately, when setting it as a composite part.

  The luminescent color conversion member (or the luminescent color conversion composite part to which this is attached) thus obtained can be used as a white illumination light source by combining with a blue light source such as a blue LED element.

  Hereinafter, the present invention will be described based on examples.

  Tables 1 to 3 show glass samples (samples A to M) used in this example.

  Each sample was prepared as follows. First, silica sand, boric acid, aluminum oxide, bismuth oxide, zinc oxide, calcium carbonate, barium carbonate, lithium carbonate, sodium carbonate, potassium carbonate, and red lead were prepared so as to have the ratio shown in the table. Subsequently, this was put into a platinum crucible, melted at 800 to 1500 ° C. for 1 to 3 hours to vitrify, and formed into a film. The glass film was pulverized with a ball mill and then classified through a 150 mesh (JIS) sieve to obtain a glass powder sample (ordinary product) having a maximum particle size of 105 μm and an average particle size of about 20 μm. For sample H, in addition to a normal particle size product, a coarse product having a maximum particle size of 150 μm and an average particle size of about 30 μm and a fine product having a maximum particle size of 10 μm and an average particle size of about 1.8 μm were prepared.

  The glass powder sample thus obtained was measured for density, coefficient of thermal expansion, and softening point. The results are shown in the table.

  The softening point was determined by DTA by further grinding a glass powder sample with a ball mill to produce a powder sample having a maximum particle size of 45 μm and an average particle size of 10 μm. The density and thermal expansion coefficient were determined by Archimedes method and TMA, respectively, after forming molten glass into a block sample and a columnar sample for characteristic measurement and annealing.

  Tables 4 to 7 show examples of the light emission color conversion member formed by sintering the above glass powder sample and inorganic phosphor powder.

Each sample was prepared as follows. First, phosphor powder was added to a glass powder sample at a ratio shown in Tables 4 to 7 and mixed to obtain a mixed powder. Further, a small amount of a resin binder was added and mixed, and then pressure-molded with a mold to prepare a button-shaped preform having a diameter of 1 cm. As the phosphor, (Y, Gd, Ce) ₃ Al ₅ O ₁₂ (P46-Y3 manufactured by Kasei Optonics Co., Ltd.) was used.

  Subsequently, the preform is sintered at a sintering temperature determined from the softening point of each glass (shown in each table), and the diameter is about 8 mm, the thickness is 0.2 mm, 0.5 mm, 1.0 mm, and 1. It processed into the disk shaped sintered compact of a magnitude | size of 5 mm or 2.0 mm.

  About the obtained sintered compact sample, the color tone of the sintered compact, the color tone and intensity of transmitted light were visually evaluated. The color tone and intensity of the transmitted light are evaluated from the transmitted light from the sintered body when the blue light of the LED is irradiated from behind the sintered body, and the color tone is preferably closer to white, and the strength is higher. The better the luminous efficiency, the better.

It is a perspective view which shows a disk shaped luminescent color conversion member. It is sectional drawing which shows a cap-shaped luminescent color conversion member. It is sectional drawing which shows the composite component for luminescent color conversion using a supporting member.

Explanation of symbols

10, 20, 30 Luminescent color conversion member 11 Inorganic phosphor 12 Glass 40 Support member

Claims (13)

A luminescent color conversion member for converting a part of blue light emitted from a blue light source into yellow light and combining with the remaining blue light to obtain white light, having a softening point higher than 500 ° C. Ri Na dispersed inorganic phosphor in the glass the total amount of alkali metal oxide is 10% or less, the content of the inorganic phosphor is 0.01 to 15% by volume%, and a glass powder emitting color conversion member, characterized in Rukoto such a sintered body of a mixed powder of an inorganic phosphor powder and.   The luminescent color conversion member according to claim 1, wherein the inorganic phosphor is an oxide phosphor. Emitting color conversion member according to claim 1 or 2 inorganic phosphor characterized in that it is a Y ₃ Al ₅ O ₁₂ phosphor. The luminescent color conversion member according to claim 1, wherein the glass has a thermal expansion coefficient of 75 × 10 ⁻⁷ / ° C. or less. The luminescent color conversion member according to claim 1, wherein the glass does not substantially contain Bi ₂ O ₃ . The luminescent color conversion member according to claim 1, wherein the glass does not substantially contain MnO, Fe ₂ O ₃ , and CeO ₂ . The glass is B ₂ O ₃ —SiO ₂ based glass, BaO—B ₂ O ₃ —SiO ₂ based glass, or ZnO—B ₂ O ₃ —SiO ₂ based glass. The luminescent color conversion member according to any one of the above.   The luminescent color conversion member according to claim 1, having a thickness of 0.2 mm or more. Glass powder, the maximum particle diameter Dmax is 150μm or less, and light emitting color conversion member according to claim 1 having an average particle diameter _{D 50} is equal to or is 2μm or more. The luminescent color conversion member according to any one of claims 1 to 9 , wherein the blue light source is a blue light emitting diode element. A luminescent color converting composite part comprising the luminescent color converting member according to any one of claims 1 to 10 and a supporting member for supporting the luminescent color converting member. A material for a light emitting color conversion member for converting a part of blue light emitted from a blue light source into yellow light and combining with the remaining blue light to obtain white light, having a softening point higher than 500 ° C. the total content of alkali metal oxides in the composition Ri Do from a mixture of glass powder and an inorganic phosphor powder is 10% or less, the content of the inorganic phosphor is 0.01 to 15% der Rukoto by volume% A material for a luminescent color conversion member characterized by the above. A white illumination light source having a blue light source and an emission color conversion member, converting a part of blue light emitted from the blue light source into yellow light and combining with the remaining blue light to obtain white light, and a softening point There higher than 500 ° C., the total amount of alkali metal oxides in the glass composition Ri Na inorganic phosphor is dispersed in the glass is less than 10%, the content of the inorganic phosphor, 0.01% by volume 15%, and the white illumination light source, which comprises using a Ru emitting color conversion member name of a sintered body of mixed powder of glass powder and an inorganic phosphor powder.

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