TW201321332A - Phosphor substrates and methods for manufacturing the same - Google Patents

Abstract

Disclosed is a method of manufacturing a phosphor substrate. Inorganic powder, chelating agent, and a combination of metal ions are mixed, and the metal ions are chelated onto a surface of the inorganic powder by the chelating agent. The inorganic powder having metal ions chelated thereon is put in a mold to process a sintering, wherein the metal ions form a nano phosphor on the surface of the inorganic powder, and the inorganic powder is bonded to form a phosphor substrate.

Description

Fluorescent substrate and method of forming same

The present invention relates to nano-phosphors, and more particularly to a method of dispersing nano-phosphors into a substrate.

How to disperse the phosphor in the base material has been an important issue in the technical field. When the size of the phosphor is smaller, the luminous efficiency should be higher. However, in practical applications, nano-scale phosphors are highly susceptible to aggregation, but are less efficient than micron-sized phosphors.

Generally, the phosphor is dispersed in an organic rubber, and the organic rubber is hardened. The phosphor used in the conventional method is of a micron order. If the size of the phosphor is reduced to the nanometer level, it is difficult to avoid the aforementioned problem of phosphor aggregation.

In U.S. Patent No. 7,879,258, a solid micron-sized (0.3 μm to 50 μm) YAG phosphor is mixed with solid alumina powder, sintered to form a fluorescent substrate, and the YAG phosphor is dispersed in alumina. However, if the nano-sized YAG phosphor is mixed with the alumina powder, it is difficult to avoid the above-mentioned problem of phosphor aggregation, and the luminous efficiency is lowered.

In summary, there is a need for new methods for dispersing nanoscale phosphors to further increase luminous efficiency.

An embodiment of the present invention provides a method for forming a fluorescent substrate, comprising: mixing an inorganic powder, a chelating agent, and combining with a metal ion, so that the metal ions are combined and sequestered to the surface of the inorganic powder by a chelating agent; The inorganic powder of the metal ion combination is sintered in a mold, and the metal ions are combined to form a nano-fluorescent body on the surface of the inorganic powder, and the inorganic powder having the surface of the nano-phosphor is bonded to form a fluorescent substrate.

An embodiment of the invention provides a fluorescent substrate formed by bonding an inorganic powder, wherein the surface of the inorganic powder has a nano-phosphor.

The present invention provides a method of forming a fluorescent substrate. As shown in Fig. 1, the inorganic powder 11, the chelating agent 13, and the metal ion 15 are first mixed, and the metal ion combination 15 is sequestered to the surface of the inorganic powder 11 by the chelating agent 13. The mixing method may be that the inorganic powder 11 is placed in a solution of the chelating agent 13 containing a metal ion combination 15 in an appropriate ratio, stirred, ultrasonically oscillated, or a combination thereof. The solvent of the chelating agent 13 solution may be deionized water or alcohol or the like. In an embodiment of the invention, the inorganic powder 11 has a size between 100 nm and 800 nm. If the size of the inorganic powder 11 is too large, void defects are likely to occur. If the size of the inorganic powder 11 is too small, agglomeration tends to occur.

Next, the inorganic powder 11 having the surface-chelated metal ion combination 15 is placed in the mold 21 as shown in Fig. 2. The mold 21 may be in the form of a flat plate, a convex plate, a concave plate, or any suitable configuration.

Next, a sintering step is performed to form the metal ion combination 15 to form the surface of the inorganic phosphor 11 on the surface of the inorganic phosphor 11, as shown in Fig. 3. This sintering step also oxidizes the chelating agent 13 to escape, and bonds the inorganic powder 11 to form the fluorescent substrate 33.

In an embodiment of the invention, the temperature of the sintering step is between 1600 ° C and 1800 ° C. If the sintering temperature is too high, the nano-phosphor is reacted with the inorganic powder to produce a second phase or a heterophase. If the sintering temperature is too low, the density is low and the transparency is insufficient. The atmosphere of the sintering step is a general air sintering with an atmospheric pressure between 1 and 5 atmospheres. If the atmospheric pressure is too high, a second phase or a heterophase is produced. The size of the nano-phosphor 31 formed on the surface of the inorganic powder 11 is between 10 nm and 150 nm. If the size of the nano-phosphor 31 is too large, the luminous efficiency is low. If the size of the nano-phosphor 31 is too small, it is easily agglomerated and cannot be effectively dispersed in the substrate. In an embodiment of the invention, the weight ratio of the inorganic powder 11 to the nano-phosphor 31 is between 10:90 and 40:60. If the ratio of the inorganic powder 11 is too high, the luminous efficiency is low and halation is likely to occur. If the ratio of the inorganic powder 11 is too low, the transparency is lowered to form a diffraction.

As shown in Fig. 4, the excitation light source 41 is placed under the fluorescent substrate 33, and when the light passes through the fluorescent substrate 33, the nano-phosphor 31 is excited to emit visible light. For example, when the nano-phosphor 31 is Y ₃ Al ₅ O ₁₂ :Ce ³⁺ , the excitation light source 41 has a wavelength between 340 nm and 360 nm, and the nano-phosphor 31 can emit 450 nm to 530 nm. Huang Guang. When the nano-phosphor 31 is Sr ₃ Al ₂ O ₆ :Eu ²⁺ , the wavelength of the excitation light source 41 is between 450 nm and 480 nm, and the nano-phosphor 31 can be emitted between 550 nm and 700 nm. It should be noted that if the wavelength of the excitation light source 41 is ultraviolet light, an ultraviolet filter layer (not shown) should be added on the outer side of the fluorescent substrate 33 to avoid harming the eyes of the user.

In an embodiment of the invention, the inorganic powder 11 may be aluminum oxide, zinc oxide, titanium oxide, or zirconium oxide, and the metal ion combination 15 may be Y ³⁺ , Al ³⁺ , a combination with Ce ³⁺ , or Al ^{3 . +} , Sr ²⁺ , and Eu ²⁺ combination. The source of Y ³⁺ may be Y(NO ₃ ) ₃ or YCl ₃ , the source of Al ³⁺ may be AlCl ₃ or Al(NO ₃ ) ₃ , and the source of Ce ³⁺ may be Ce(NO ₃ ) ₃ or CeCl _{3 .} The source of Sr ²⁺ may be Sr(NO ₃ ) ₂ or SrCl ₂ , and the source of Eu ²⁺ may be EuCl ₂ or Eu(NO ₃ ) ₂ . The type of the chelating agent 13 is, for example, tartaric acid, citric acid, stearic acid or a combination thereof. Further, the type of the chelating agent 13 can be preferably adjusted depending on the type of the metal ion 15. For example, the chelating agent 13 of the inorganic powder and the metal ion Y ³⁺ may be citric acid or tartaric acid, and the chelating agent 13 of the inorganic powder and the metal ion Al ³⁺ may be tartaric acid or stearic acid, inorganic powder and metal ion Ce ³ 13 ⁺ chelating agents may be citric acid or tartaric acid, an inorganic powder and metal ion chelators Sr ²⁺ may be 13 or tartaric acid, an inorganic powder and Eu ²⁺ metal ion chelating agent may be citric acid or tartaric 13 . The nano-phosphor 31 in the fluorescent substrate 33 formed after sintering is Y ₃ Al ₅ O ₁₂ :Ce ³⁺ or Sr ₃ Al ₂ O ₆ :Eu ²⁺ . In another embodiment of the present invention, an alumina powder having a surface in combination with Y ³⁺ , Al ³⁺ , and Ce ³⁺ may be bonded to the surface with Al ³⁺ , Sr ²⁺ , and Eu ^{2+ .} The combined alumina powder is mixed and placed in a mold 21, followed by a sintering reaction. As a result, the nano-phosphor 31 in the fluorescent substrate 33 is a combination of Y ₃ Al ₅ O ₁₂ :Ce ³⁺ and Sr ₃ Al ₂ O ₆ :Eu ²⁺ fluorescent powder.

It is to be understood that the inorganic powder 11, the chelating agent 13, the metal ion combination 15, and the finally formed nano-phosphor 31 of the present invention are not limited to the above-mentioned species. The metal ion combination 15 which can be chelated to the surface of the inorganic powder 11 by the chelating agent 13 and the nano-phosphor 31 formed on the surface of the inorganic powder 11 after sintering are all covered by the present invention.

The above and other objects, features and advantages of the present invention will become more apparent and understood.

[Examples]

Example 1

57.509 g of Y(NO ₃ ) ₃ , 93.78781 g of Al(N0 ₃ ) ₃ and 0.8685 g of Ce(N0 ₃ ) _{3 were} dissolved in 2000 mL of deionized water solvent. After 150 g of the tartaric acid chelating agent was added to the above salt solution, 450 g of alumina powder (particle diameter: 300 nm) was further added. After stirring at 65 ° C for 1 hour, the mixture was heated to 240 ° C and stirred for 5 hours. After the solution was evaporated, the above salts were chelated to the alumina powder, and after drying, the surface was chelated with metal ion-containing alumina.

Next, alumina having a surface chelated with metal ions was placed in a mold of 15 cm × 15 cm × 5 cm, and sintered at 1000 ° C for 2 hours under air of 1 atm to form a nano-phosphor YAG on the surface of the alumina powder. And sintered at 1600 ° C to form a fluorescent substrate in which alumina is bonded to each other. In the fluorescent substrate, the weight ratio of the nano-phosphor YAG to alumina was 10:90, and it was observed under TEM that the size of the nano-phosphor YAG was about 20 nm to 150 nm.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.8 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous flux of 20.2 lumens (lm) and a luminous efficiency (lm/W) of 73.02.

Example 2

57.509 g of Y(NO ₃ ) ₃ , 93.78781 g of Al(N0 ₃ ) ₃ and 0.8685 g of Ce(N0 ₃ ) _{3 were} dissolved in 2000 mL of deionized water solvent. After 150 g of the tartaric acid chelating agent was added to the above salt solution, 400 g of alumina powder (particle diameter: 300 nm) was further added. After stirring at 65 ° C for 1 hour, the mixture was heated to 240 ° C and stirred for 5 hours. After the solution was evaporated, the above salts were chelated to the alumina powder, and after drying, the surface was chelated with metal ion-containing alumina.

Next, alumina having a surface chelated with metal ions was placed in a mold of 15 cm × 15 cm × 5 cm, and sintered at 1000 ° C for 2 hours under air of 1 atm to form a nano-phosphor YAG on the surface of the alumina powder. And sintered at 1600 ° C to form a fluorescent substrate in which alumina is bonded to each other. In the fluorescent substrate, the weight ratio of the nano-phosphor YAG to the alumina was 20:80, and it was observed under TEM that the size of the nano-phosphor YAG was about 20 to 150 nm.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.8 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous intensity of 20.8 lumens (lm) and a luminous efficiency (lm/W) of 75.19.

Example 3

57.509 g of Y(NO ₃ ) ₃ , 93.78781 g of Al(N0 ₃ ) ₃ and 0.8685 g of Ce(N0 ₃ ) _{3 were} dissolved in 2000 mL of deionized water solvent. After 150 g of the tartaric acid chelating agent was added to the above salt solution, 350 g of alumina powder (particle diameter: 300 nm) was further added. After stirring at 65 ° C for 1 hour, the mixture was heated to 240 ° C and stirred for 5 hours. After the solution was evaporated, the above salts were chelated to the alumina powder, and after drying, the surface was chelated with metal ion-containing alumina.

Next, alumina having a surface chelated with metal ions was placed in a mold of 15 cm × 15 cm × 5 cm, and sintered at 1000 ° C for 2 hours under air of 1 atm to form a nano-phosphor YAG on the surface of the alumina powder. And sintered at 1600 ° C to form a fluorescent substrate in which alumina is bonded to each other. In the fluorescent substrate, the weight ratio of the nano-phosphor YAG to the alumina was 30:70, and the size of the nano-phosphor YAG was observed to be about 20 nm to 150 nm under TEM.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.8 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous flux of 21.1 lumens (lm) and a luminous efficiency (lm/W) of 76.28.

Example 4

57.509 g of Y(NO ₃ ) ₃ , 93.78781 g of Al(N0 ₃ ) ₃ and 0.8685 g of Ce(N0 ₃ ) _{3 were} dissolved in 2000 mL of deionized water solvent. After 150 g of the tartaric acid chelating agent was added to the above salt solution, 300 g of alumina powder (particle diameter: 300 nm) was further added. After stirring at 65 ° C for 1 hour, the mixture was heated to 240 ° C and stirred for 5 hours. After the solution was evaporated, the above salts were chelated to the alumina powder, and after drying, the surface was chelated with metal ion-containing alumina.

Next, alumina having a surface chelated with metal ions was placed in a mold of 15 cm × 15 cm × 5 cm, and sintered at 1000 ° C for 2 hours under air of 1 atm to form a nano-phosphor YAG on the surface of the alumina powder. And sintered at 1600 ° C to form a fluorescent substrate in which alumina is bonded to each other. In the fluorescent substrate, the weight ratio of the nano-phosphor YAG to the alumina was 40:60, and the size of the nano-phosphor YAG was observed to be about 20 nm to 150 nm under TEM.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.8 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous flux of 21.3 lumens (lm) and a luminous efficiency (lm/W) of 77.

Example 5

57.509 g of Y(NO ₃ ) ₃ , 93.78781 g of Al(N0 ₃ ) ₃ and 0.8685 g of Ce(N0 ₃ ) _{3 were} dissolved in 2000 mL of deionized water solvent. After 150 g of the tartaric acid chelating agent was added to the above salt solution, 450 g of zirconia powder (particle diameter: 500 nm) was further added. After stirring at 65 ° C for 1 hour, the mixture was heated to 240 ° C and stirred for 5 hours. After the solution was evaporated, the above salts were chelated, and the above salts were chelated to the zirconia powder. After drying, the surface was chelated with metal ions. Zirconia.

Next, the surface-chelated zirconium oxide with metal ions was placed in a mold of 15 cm × 15 cm × 5 cm, and sintered at 1000 ° C for 2 hours under air of 1 atm to form a nano-phosphor YAG on the surface of the zirconia powder. And sintered at 1600 ° C to form a fluorescent substrate formed by zirconia bonding to each other. In the phosphor substrate, the weight ratio of the nano-phosphor YAG to the zirconia was 10:90, and the size of the nano-phosphor YAG was observed to be about 50 to 200 nm under TEM.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.77 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous flux of 20.2 lumens (lm) and a luminous efficiency (lm/W) of 73.2.

Example 6

57.509 g of Y(NO ₃ ) ₃ , 93.78781 g of Al(N0 ₃ ) ₃ and 0.8685 g of Ce(N0 ₃ ) _{3 were} dissolved in 2000 mL of deionized water solvent. After 150 g of the tartaric acid chelating agent was added to the above salt solution, 400 g of zirconia powder (particle diameter: 500 nm) was further added. After stirring at 65 ° C for 1 hour, the mixture was heated to 240 ° C and stirred for 5 hours. After the solution was evaporated, the above salts were chelated, and the above salts were chelated to the zirconia powder. After drying, the surface was chelated with metal ions. Zirconia.

Next, the surface-chelated zirconium oxide with metal ions was placed in a mold of 15 cm × 15 cm × 5 cm, and sintered at 1000 ° C for 2 hours under air of 1 atm to form a nano-phosphor YAG on the surface of the zirconia powder. And sintered at 1600 ° C to form a fluorescent substrate formed by zirconia bonding to each other. In the phosphor substrate, the weight ratio of the nano-phosphor YAG to the zirconia was 20:80, and the size of the nano-phosphor YAG was observed to be about 50 to 200 nm under TEM.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.77 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous flux of 20.5 lumens (lm) and a luminous efficiency (lm/W) of 74.2.

Comparative example 1

Take 1g of YAG (purchased from Nichia Chemical Co., Ltd., particle size 5~8μm) and mix it with 9g of rubber (purchased from Dow Corning, silicone rubber), and put it into a mold of size Φ1cm×3cm to heat harden. The rice phosphor YAG is dispersed in the glue to form a fluorescent substrate. In the fluorescent substrate, the weight ratio of the nano-phosphor YAG to the rubber material is 10:90, and the size of the nano-phosphor YAG aggregation group is about 15 to 40 μm as observed by SEM sectioning.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.8 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous flux of 20 lumens (lm) and a luminous efficiency (lm/W) of 72.1.

Comparative example 2

Take 2g of YAG (purchased from Nichia Chemical Co., Ltd., particle size 5~8μm) and mix it with 8g of rubber (purchased from Dow Corning, silicone rubber), and put it into a mold of size Φ1cm×3cm to heat harden. The rice phosphor YAG is dispersed in the glue to form a fluorescent substrate. In the fluorescent substrate, the weight ratio of the nano-phosphor YAG to the rubber material was 20:80, and the size of the nano-phosphor YAG aggregated group was about 15 to 40 μm as observed by SEM observation.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.8 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous flux of 20.5 lumens (lm) and a luminous efficiency (lm/W) of 74.

Comparative example 3

2 g of YAG (purchased from Nichia Chemical Co., Ltd., particle size 100 nm) was mixed with 8 g of alumina, placed in a mold of 5 cm × 5 cm × 1 cm, and sintered at 1200 ° C to disperse the nano-phosphor YAG in alumina. And sintered at 1600 ° C to form a fluorescent substrate. In the fluorescent substrate, the weight ratio of the nano-phosphor YAG to the alumina was 20:80, and it was observed under SEM that the size of the nano-phosphor YAG aggregates was about 400 nm.

The fluorescent substrate was covered with an LED light source, and the LED light source was driven at a current of 0.1 amps with a voltage of 2.8 volts to emit blue light having a wavelength of 340 nm. The blue light excites the nano-phosphor YAG in the fluorescent substrate, and the yellow light and the blue light are mixed to form white light. The white light has a luminous flux of 17.4 lumens (lm) and a luminous efficiency (lm/W) of 67.

From the comparison between Comparative Example 3 and the examples, it was found that the nano-sized phosphor was directly mixed with alumina and sintered, and the nano-phosphor was not efficiently dispersed in the alumina.

The first table is the excitation parameter and the luminous efficiency of the fluorescent substrate of Examples 1-6.

While the invention has been described above in terms of several preferred embodiments, it is not intended to limit the invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

11. . . Inorganic powder

13. . . Chelating agent

15. . . Metal ion combination

twenty one. . . Mold

31. . . Nano-fluorescent body

33. . . Fluorescent substrate

41. . . Excitation source

1 to 4 are schematic views showing the flow of a fluorescent substrate in an embodiment of the present invention.

11. . . Inorganic powder

31. . . Nano-fluorescent body

33. . . Fluorescent substrate

Claims (10)

A method for forming a fluorescent substrate, comprising: mixing an inorganic powder, a chelating agent, and a metal ion, and combining the metal ions by the chelating agent to the surface of the inorganic powder; The inorganic powder combined with the metal ion is formed into a mold and sintered, and the metal ions are combined to form a nano-fluorescent body on the surface of the inorganic powder, and the inorganic powder having a nano-fluorescent surface is bonded to the surface. To form a fluorescent substrate. The method of forming a fluorescent substrate according to claim 1, wherein the inorganic powder comprises alumina, zinc oxide, titanium oxide, or zirconium oxide. The method of forming a fluorescent substrate according to claim 1, wherein the chelating agent comprises tartaric acid, citric acid, stearic acid, or a combination thereof. The method for forming a fluorescent substrate according to claim 1, wherein the metal ion combination comprises Al ³⁺ , a combination of Eu ²⁺ and Sr ²⁺ , or Al ³⁺ , Y ³⁺ and Ce ³⁺ Combined, and the nano-phosphor includes Y ₃ Al ₅ O ₁₂ :Ce ³⁺ or Sr ₃ Al ₂ O ₆ :Eu ²⁺ . The method for forming a fluorescent substrate according to claim 1, wherein the inorganic powder has a size between 100 nm and 800 nm, and the nano-phosphor has a size between 10 nm and 150 nm. The method for forming a fluorescent substrate according to claim 1, wherein the weight ratio of the inorganic powder to the nano-phosphor is between 10:90 and 40:60. A fluorescent substrate formed by bonding an inorganic powder, wherein the surface of the inorganic powder has a nano-fluorescent body. The fluorescent substrate of claim 7, wherein the inorganic powder comprises aluminum oxide, zinc oxide, titanium oxide, or zirconium oxide, and the nano phosphor comprises Y ₃ Al ₅ O ₁₂ :Ce ³⁺ Or Sr ₃ Al ₂ O ₆ :Eu ²⁺ . The fluorescent substrate of claim 7, wherein the inorganic powder has a size between 100 and 800 nm, and the nano-phosphor has a size between 10 and 150 nm. The fluorescent substrate of claim 7, wherein the weight ratio of the inorganic powder to the nano-phosphor is between 10:90 and 40:60.