TWI440696B - Method of preparing oxynitride-based phosphor powder and structure of light emitting diode - Google Patents

Description

Preparation method of oxynitride fluorescent powder and structure of light emitting diode

The invention relates to a method for preparing a phosphor powder and a structure of a light emitting diode, and particularly to a method for preparing a red oxynitride phosphor powder and a light emitting diode comprising the red nitrogen oxide phosphor powder structure.

Based on the environmental awareness of energy saving, carbon reduction and sustainable development, the world's advanced countries are gradually eliminating traditional lighting, and then choosing white LEDs (white LED). The advantage of the white light emitting diode is that it is small in size and can be adjusted with the application equipment. Moreover, the white light emitting diode has low power consumption, which is only 1/8 to 1/10 of the conventional light bulb, 1/2 of the fluorescent lamp, and has a long life of more than 100,000 hours. In addition, the white light emitting diode has a low heat generation rate and a fast reaction speed, so it is very suitable for high frequency operation. White light-emitting diodes can solve the problem that incandescent light bulbs are difficult to overcome. They can be used as lighting and display light sources in the 21st century, and they have both power saving and environmental protection concepts. Therefore, they are called "green lighting sources."

1996, U.S. Patent No. 5,998,925 proposes a first white light-emitting diodes, which by blue-based light-emitting diode (blue LED) excitation of cerium-doped yttrium aluminum garnet _{(Y 3 Al 5 O 12:} Ce 3+ YAG) phosphor powder produces yellow fluorescence, and the yellow light emitted by the yellow phosphor can be mixed with blue light to produce white light. However, this white light-emitting diode is inferior in color rendering due to the lack of a red portion. Further, it is known that commercially available red phosphors rapidly degrade in radiation intensity when the temperature is raised above 150 °C.

In view of the above, the present invention provides a method for preparing a red oxynitride phosphor having excellent thermal stability and a light emitting diode structure comprising the red oxynitride phosphor.

The invention provides a preparation method of nitrogen oxide fluorescent powder. First, tantalum nitride (Si ₃ N ₄ ), aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ), and antimony trioxide (Pr ₂ O ₃ ) are mixed and ground into a mixture. Then, the mixture is sintered to form an oxynitride phosphor represented by the formula (1), Si _6-z Al _z O _z N _8-z : xPr ^{3 +} formula (1), wherein 鐠 is an activation center, 0 z 4.2, and the atomic ratio x ranges from 0.05 to 2%.

In an embodiment of the present invention, the sintering is a solid state synthesis method performed under an atmosphere of nitrogen or an inert gas, the sintering temperature is 1,500 degrees Celsius to 2,100 degrees Celsius, the sintering time is 1 hour to 10 hours, and the pressure is 0.5 MPa. Up to 1 MPa.

In one embodiment of the invention, the sintering is carried out under a nitrogen atmosphere at a sintering temperature of 1,950 degrees Celsius, a sintering time of 2 hours, and a pressure of 0.92 MPa.

In an embodiment of the invention, the oxynitride phosphor has a radiation wavelength of at least 600 nm and a maximum of not more than 700 nm, and the oxynitride fluoro powder is suitable for 440~ of a light-emitting diode chip. Light excitation at 480 nm wavelength.

In an embodiment of the invention, the NOx phosphor powder has a main emission wavelength of 622 nm and a full width at half maximum of less than 30 nm.

In one embodiment of the invention, the oxynitride phosphor maintains at least 80% of its brightness at 25 ° C at 300 ° C.

The invention further provides a light emitting diode structure comprising a light emitting diode chip and a phosphor powder layer. The light-emitting diode wafer has light having a wavelength of 400 to 480 nm. The phosphor layer covers the light-emitting diode wafer and includes an oxynitride phosphor represented by the formula (1), Si _6-z Al _z O _z N _8-z : xPr ³⁺ (1), wherein鐠 is the activation center, 0 z 4.2, and the atomic ratio x ranges from 0.05 to 2%, and wherein the oxynitride fluorescein is a red fluorescing powder and the oxynitride fluorotic powder has a full width at half maximum of less than 30 nm.

In an embodiment of the invention, the oxynitride phosphor has a radiation wavelength of 600 to 700 nm and a full width at half maximum of less than 30 nm.

In an embodiment of the invention, the NOx oxide phosphor has a main emission wavelength of 622 nm.

In one embodiment of the invention, the oxynitride phosphor maintains at least 80% of its brightness at 25 ° C at 300 ° C.

Based on the above, the preparation method of the red oxynitride fluorescent powder of the present invention is simple, and is suitable for mass production, and the synthesized red oxynitride fluorescent powder is better in heat stability than the commercially available red fluorescent powder, and is heated to 300 ° C. There are still more than 80% brightness, so it has great industrial application value.

The above described features and advantages of the present invention will be more apparent from the following description.

FIG. 1 is a flow chart showing the preparation of red oxynitride phosphor according to an embodiment of the invention.

Referring to FIG. 1, first, step S100 is performed to mix tantalum nitride (Si ₃ N ₄ ), aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ) and antimony trioxide (Pr ₂ O ₃ ). Grind into a mixture. Next, proceeding to step S110, the mixture is sintered to form a red oxynitride phosphor represented by the formula (1), Si _6-z Al _z O _z N _8-z : xPr ³⁺ (1), wherein鐠 is the activation center (or illuminating center), 0 z 4.2, and the atomic ratio x ranges from 0.05 to 2%.

The above sintering is a solid state synthesis method, which is carried out under nitrogen or an inert gas. The inert gas is, for example, helium, neon or argon. The sintering temperature is, for example, 1,500 degrees Celsius to 2,100 degrees Celsius. The sintering time is, for example, 1 hour to 10 hours. The pressure is, for example, 0.5 MPa to 1 MPa.

The red oxynitride phosphor of the present invention can be excited by light of a wavelength of 440 to 480 nm of a blue light-emitting diode wafer, and has a radiation wavelength of 600 to 700 nm. Specifically, the red oxynitride phosphor of the present invention has a radiation wavelength of at least 600 nm and a maximum of not more than 700 nm, and the red oxynitride phosphor is suitable for 440-480 nm of a light-emitting diode wafer. The wavelength of light is excited. In one embodiment, the red oxynitride phosphor has a major emission wavelength of 622 nm and a full width at half maximum of less than 30 nm. In addition, the red oxynitride phosphor maintains at least 80% of its brightness at 25 ° C at 300 ° C.

The red oxynitride phosphor of the present invention can be applied to a blue light-emitting diode wafer to produce a white light-emitting diode. Figure 2 is based on the system A schematic cross-sectional view of the structure of the light-emitting diode shown in the embodiment.

Referring to FIG. 2 , the LED structure 200 includes a substrate 210 , a blue LED wafer 220 , and a phosphor layer 230 . The substrate 210 is a base that carries the blue light emitting diode wafer 220. The blue light emitting diode wafer 220 is attached to the substrate 210. The blue light-emitting diode chip 220 has light of a wavelength of 400 to 480 nm, and may be composed of a semiconductor material such as a multi-component compound of the VA group, including gallium nitride (InGaN), gallium nitride/germanium carbide (GaN/SiC). ) or any combination of the above. The blue light emitting diode chip 220 is electrically connected to the holder pin 250 through the bonding wire 240. The phosphor layer 230 is disposed on the blue LED chip 220. Specifically, the phosphor layer 230 is disposed on the surface and the periphery of the blue light-emitting diode wafer 220, and further covers a part of the two bonding wires.

The phosphor layer 230 may be a single type of phosphor powder or a mixture of two or more kinds of phosphor powders, and these phosphor powders are uniformly dispersed in the phosphor powder layer 230. When the phosphor powder layer 230 is a single type of phosphor powder, the phosphor powder is, for example, a phosphor powder having a garnet or a silicate phosphor powder. When the phosphor powder layer 230 contains two or more types of phosphor powder, the phosphor powder includes at least the first phosphor powder 231 and the second phosphor powder 232. In one embodiment, the first phosphor powder 231 is, for example, a red oxynitride phosphor represented by the formula (1) of the present invention, Si _6-z Al _z O _z N _8-z : xPr ³⁺ ( 1), where 鐠 is the activation center, 0 z 4.2, and the atomic ratio x ranges from 0.05 to 2%.

In particular, the red oxynitride phosphor of the present invention can be The blue light-emitting diode wafer 210 is excited by light of a wavelength of 400 to 480 nm, and has a radiation wavelength of 600 to 700 nm.

In addition, the second phosphor powder 232 is, for example, yellow phosphor powder and/or green phosphor powder, and the green phosphor powder is, for example, a niobate phosphor powder having a chemical formula of CaSc ₂ O ₄ :Re, and Re is Eu ³⁺ Or Ce ³⁺ . Therefore, the phosphor layer 230 of the present invention is converted into a longer wavelength by the blue light emitted from the blue light-emitting diode wafer 210, and then mixed with the emission wavelength of the blue wafer to generate a white light emitting diode structure 200.

Next, an example of the preparation of the red oxynitride phosphor of the present invention will be described.

Example 1

Referring to Table 1, each of the tantalum nitride, aluminum nitride, aluminum oxide, and antimony trioxide was weighed to a suitable weight and then uniformly mixed and ground into a mixture in a mortar. Then, the mixture was calcined at a temperature of 1,950 ° C and a nitrogen pressure of 0.92 MPa for 2 hours to obtain a red product Si _5.8 Al _0.2 O _0.2 N _7.8 :Pr ³⁺ , wherein the atomic ratio x of Pr ³⁺ was 0.103%.

Figure 3 is a X-ray powder diffraction pattern of the red oxynitride phosphor formed in Example 1. As shown in FIG. 3, the red oxynitride phosphor (Si _5.8 Al _0.2 O _0.2 N _7.8 :Pr ³⁺ , wherein the atomic ratio x of Pr ³⁺ is 0.103%) prepared in Example 1 of the present invention is a pure phase. The crystal structure is a hexagonal (primitive unit cell).

4 is an excitation spectrum diagram (left side) and a radiation spectrum diagram (right side) of the red oxynitride phosphor of Example 1. As shown in FIG. 4, the red oxynitride phosphor of the present invention can be excited by a 460 nm blue LED to produce a red light of 622 nm, and a full width at half maximum of less than 30 nm, wherein the excitation band at 440 to 520 nm is ³ H. ₄ → ³ P _n (n=0,1,2) transition consisting of ¹ D ₂ → ³ H ₄ , ³ P ₀ → ³ H ₆ , ³ P ₀ → ³ F ₂ transitions in the 600~650 nm emission band composition.

Fig. 5 is a graph showing the relationship between the elevated temperature and the radiation intensity of the red oxynitride phosphor of Example 1, wherein the radiation intensity is based on the radiation at 25 ° C and 622 nm. Fig. 6 is a graph showing the relationship between the rising temperature and the radiation intensity of the red oxynitride phosphor of Example 1, wherein the radiation intensity is based on the radiation at 25 ° C and 622 nm. Referring to FIG. 5, as the temperature is raised from room temperature of 25 ° C to 300 ° C, the change in the radiation intensity of the red oxynitride phosphor of the present invention is not large. Based on the radiation intensity at 25 ° C and 622 nm, it can be seen that the red oxynitride phosphor of the present invention maintains its brightness at 300 ° C at 86 ° C as shown in FIG. 6 .

In summary, the present invention utilizes tantalum nitride, aluminum nitride, aluminum oxide and antimony trioxide as raw materials, and the red oxynitride phosphor of the present invention can be obtained through a simple grinding and sintering process. The preparation process is simple and can be synthesized in a large amount.

In addition, the red oxynitride phosphor of the present invention can be illuminated by blue The polar body wafer is excited by light of 440 to 480 nm wavelength, and its emission wavelength is 600 to 700 nm, and the red oxynitride phosphor has good thermal stability, and when it is heated to 300 ° C, it still has more than 80% brightness, so it is extremely Industrial application value.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

S100, S110‧‧‧ steps

200‧‧‧Lighting diode structure

210‧‧‧Substrate

220‧‧‧Lighting elements

230‧‧‧Fluorescent powder layer

231‧‧‧First Fluorescent Powder

232‧‧‧Second Fluorescent Powder

240‧‧‧welding line

250‧‧‧ bracket pin

FIG. 1 is a flow chart showing the preparation of red oxynitride phosphor according to an embodiment of the invention.

2 is a cross-sectional view showing a structure of a light emitting diode according to an embodiment of the invention.

Figure 3 is a X-ray powder diffraction pattern of the red oxynitride phosphor formed in Example 1.

4 is an excitation spectrum diagram (left side) and a radiation spectrum diagram (right side) of the red oxynitride phosphor of Example 1.

Fig. 5 is a graph showing the relationship between the elevated temperature and the radiation intensity of the red oxynitride phosphor of Example 1, wherein the radiation intensity is based on the radiation at 25 ° C and 622 nm.

Fig. 6 is a graph showing the relationship between the rising temperature and the radiation intensity of the red oxynitride phosphor of Example 1, wherein the radiation intensity is based on the radiation at 25 ° C and 622 nm.

S100, S110‧‧‧ steps

Claims (16)

A method for preparing an oxynitride phosphor powder, comprising: cerium nitride (Si ₃ N ₄ ), aluminum nitride (AlN), aluminum oxide (Al ₂ O ₃ ) and antimony trioxide (Pr ₂ O ₃ ) Mixing and grinding into a mixture; and sintering the mixture to form an oxynitride phosphor represented by the formula (1), Si _6-z Al _z O _z N _8-z : xPr ³⁺ (1) , where 鐠 is the activation center, 0 z 4.2, and the atomic ratio x ranges from 0.05 to 2%. The method for producing an oxynitride phosphor according to claim 1, wherein the sintering is a solid state synthesis method, which is carried out under an atmosphere of nitrogen or an inert gas. The method for preparing an oxynitride phosphor according to claim 1, wherein the sintering temperature of the mixture is 1,500 to 2,100 degrees Celsius, the sintering time is 1 hour to 10 hours, and the pressure is 0.5 MPa to 1 MPa. . The method for producing an oxynitride phosphor according to claim 1, wherein the sintering is carried out under a nitrogen atmosphere at a sintering temperature of 1,950 ° C, a sintering time of 2 hours, and a pressure of 0.92 MPa. The method for preparing an oxynitride phosphor according to claim 1, wherein the oxynitride powder has a radiation wavelength of at least 600 nm and a maximum of not more than 700 nm, and the NOx The phosphor powder is suitable for excitation by light of a wavelength of 440 to 480 nm of a light-emitting diode chip. The oxynitride phosphine powder as described in claim 5 The preparation method, wherein the oxynitride phosphor has a main emission wavelength of 622 nm and a full width at half maximum of less than 30 nm. The method for preparing an oxynitride phosphor according to claim 1, wherein the oxynitride phosphor maintains at least 80 brightness of the oxynitride phosphor at 25 ° C at a brightness of 300 ° C. %. A light emitting diode structure comprising: a light emitting diode wafer having a radiation wavelength of 400 to 480 nm; and a phosphor powder layer disposed on the light emitting diode wafer, and comprising the formula (1) An oxynitride phosphor, Si _6-z Al _z O _z N _8-z : xPr ³⁺ (1), wherein 鐠 is the activation center, 0 z 4.2, and the atomic ratio x ranges from 0.05 to 2%, and wherein the oxynitride fluorescer is a red fluoresce powder and the oxynitride fluoropowder has a full width at half maximum of less than 30 nm. The light-emitting diode structure according to claim 8, wherein the oxynitride phosphor has a radiation wavelength of 600 to 700 nm. The light-emitting diode structure according to claim 8, wherein the NOx phosphor powder has a main emission wavelength of 622 nm. The light-emitting diode structure of claim 8, wherein the oxynitride phosphor maintains at least 80% of the brightness of the oxynitride phosphor at 25 ° C at a brightness of 300 ° C. An oxynitride phosphor comprising a structure represented by the formula (1): Si _6-z Al _z O _z N _8-z : xPr ³⁺ (1), wherein 鐠 is an activation center, 0 z 4.2, and the atomic ratio x ranges from 0.05 to 2%. The oxynitride phosphor of claim 12, wherein the oxynitride phosphor is a red phosphor and the oxynitride has a full width at half maximum of less than 30 nm. The oxynitride fluorotic powder according to claim 12, wherein the oxynitride fluorescer has a radiation wavelength of 600 to 700 nm. The oxynitride phosphor according to claim 12, wherein the NOx phosphor has a main emission wavelength of 622 nm. The oxynitride phosphor of claim 12, wherein the oxynitride phosphor maintains at least 80% of the brightness of the oxynitride phosphor at 25 ° C at a brightness of 300 ° C.