TWI390014B - Warm white light emitting diodes and their lithium luminescent powder - Google Patents

Description

Warm white light emitting diode and its lithium fluoride powder

The invention relates to a fluorescent powder and a warm white light diode, in particular to a fluorescent powder capable of creating high luminous efficiency and a warm white light diode thereof.

Light-emitting diodes were introduced in 1965 when engineers developed the first light-emitting diode device based on GaAs (gallium arsenide). This is a low-power light-emitting diode with a luminous flux of F≦0.01 lumens that illuminates in the red region. In the 70s and 80s, the development of light-emitting diodes was very slow. By the early 1990s, the luminous flux of better green light-emitting diodes did not exceed 0.1-0.3 lumens.

Since 1968, fluorescent powders and phosphor-based spectral conversion structures have been widely used in light-emitting diode technology. Initially appeared is a conversion device that increases the illuminating frequency, converting the near-infrared luminescence of GaAsP diodes into red or green light by the action of anti-Stokes phosphors (please refer to Berg, Din A., LED, (Mir) ), 1975). Later, many researchers tried to convert the near-ultraviolet luminescence of GaN (gallium nitride) diodes into visible light.

However, after the invention of Professor Nakamura of Japan, the development of the light-emitting diode was very rapid. In the 1990s, Professor Nakamura proposed a new structure of nitride semiconductors based on indium nitride and gallium nitride. This semiconductor is unique in that it contains a large number of nano-sized "quantum wells" that are synthesized by adding oxygen as an active element during the synthesis of the nitride. Nakamura Shuichi has a comprehensive overview of this in his 1997 monograph "Blue laser" (see S. Nakamura. Blue laser, Springer Verlag, Berlin. 1997).

Experts from Japan's Nichia (S. Nakamura and S. Shimizu) have made breakthroughs in this research direction. They have developed a blue-emitting GaInN (indium gallium nitride) heterojunction (Junction). A new light source consisting of yellow yttrium aluminum garnet phosphor powder (Y ₃ Al ₅ O ₁₂ ) covering its surface (please refer to the German DE6933829T patent approved by S. Nakamura on 11, 05, 2006, and S. Shimizu Y. 11,01,2005 approved the Republic of China TW156177B patent).

The application of these two inventions enables the realization of white light-emitting diodes for lighting, lighting and indicating purposes. The use of such yttrium aluminum garnet phosphor in a light-emitting diode is described in detail in the TW156177B patent. However, the applicant in this case believes that the invention is not absolutely innovative. The case uses this as a prototype. The following are the innovations listed in the patent case: 1. Using the blue-emitting GaInN heterojunction as the structural basis of the light-emitting diode; 2. Using synergy in the light-emitting diode Light-emitting phosphor powder particles; 3. By directing two parts of the luminescence, that is, the GaInN semiconductor heterojunction direct luminescence and the luminescent powder particles are mixed by their excitation luminescence, finally obtaining white light; and 4. using the chemical formula Y ₃ Aluminium garnet of Al ₅ O ₁₂ :Ce and a derivative thereof (such as a phosphor powder composed of (Y, Gd) ₃ (Al, Ga, Sc) ₅ O ₁₂ :Ce) particles. There is a large body of literature on the heterogeneity of blue-emitting GaInN semiconductors, but the technical documents disclosed by S. Nakamura and G. Fasol et al. in 1998 (please refer to S. Nakamura and G. Fasol, The blue laser diodes. Berlin, Springer). Only some of them are cited in 1998). The results of the nitride heterojunction developed by S. Nakamura for efficient luminescence based on quantum effects have been shared by the whole world, so it is not worthy of Nichia.

The synergistic light-transfer powder for the light-emitting diode, as described above, is produced by a detailed process using an anti-Stokes material (see Berg, Din A., LED, "Mir", 1975). The use of short-wave radiation to excite various substances has been described in detail in many academic papers (please refer to P. Pringshein, Phluorescence and phosphorescence, IL, 1950; G. Blasse, P. Grabmaier, Luminescence materials, Pergamon press, NY, respectively). , 1995; and S. Shionoja, W. Yen, Handbook of phosphors, NY, 1999.). The inventors believe that the method of obtaining relatively long-wavelength radiation from phosphor powder by means of a light-emitting diode emitting short-wave radiation does not have substantial innovation significance and significant distinguishing characteristics. There are various light sources for exciting the luminescence of other substances, including discharge light sources: 1. gas discharge of mercury vapor; 2. gas discharge of nitrogen; and 3. gas discharge of helium and neon. In addition, laser radiation is also widely used to stimulate fluorescent powder illumination, such as nitrogen lasers, Nd:YAG lasers that output third harmonics and fourth harmonics.

A scheme for exciting a phosphor with a semiconductor light-emitting diode has been mentioned more than once (please refer to S. Nakamura and G. Fasol, The blue laser diodes. Berlin, Springer, 1998).

The following is a question about obtaining white light by combining two or three basic light sources. The monochromatic light obtained by the dispersion of light, such as blue light and yellow light, green light and red light, red light, green light and blue light, etc., the physical basis of the practice of obtaining white light was first laid by Newton. The proposed theory of light color (ie, the principle of Newton's complementary color) has developed. This physical principle was widely used in printing and photography in the 19th and 20th centuries, especially black and white and color television technology. For example, Zworegin uses a blue light and a yellow light to make a white-and-white black-and-white picture tube display (please refer to HWLeverenz, An introduction to Luminescence of Solids, NY, 1950), which is a complex in the field of color TV technology. The technical solution: not only the primary color light needs to have a complete color difference coefficient, but also the primary color is compensated in quantity to obtain the white light of the chromaticity standard.

Problems similar to the above physical principles in the field of lighting technology have also been solved (please refer to LM Kogan LED lighttechnic, Moscow, Ho. 5, pp. 16-20. (2002)): Mercury vapor discharge emits blue light, exciting YVO ₄ :Eu Red light is emitted, and finally white light is obtained which is close to the white light source. The short-wave discharge of helium and neon ensures that the gas discharge plasma plate can produce red, green, blue and white light. Therefore, replacing the gas discharge source with a semiconductor light-emitting diode to excite the phosphor powder is a significant technological advancement in the process of perfecting the illumination, information and indication system, and is also an inevitable trend.

Blue light sources that produce a variety of optical effects are widely used. For example, long-lasting and ultra-long afterglow blue light sources are widely used in radar positioning technology. The original blue light is optically combined with the yellow-white afterglow of the illuminating display in one device.

Therefore, before Nichia proposed their research results, the physical principle of synthesizing achromatic white light from two or three light sources has long been known and applied.

The use of yttrium aluminum garnet as a fluorescent material has caused many legal disputes, as it is only possible to use this material with the permission of Nichia (therefore even new research directions have emerged - for illuminating two) The polar non-yttrium aluminum garnet fluorescing), this permission was later proved to be completely unfounded. First, the appearance of fluorescent materials and displays made of yttrium aluminum garnet is much earlier than that of Japanese researchers (please refer to G. Blasse, P. Grabmaier, Luminescence materials, Pergamon press, NY, 1995, respectively; S. Shionoja, W. Yen, Handbook of phosphors, NY, 1999.; HW Leverenz, An introduction to Luminescence of Solids, NY, 1950 and VAAbramov, patent USSR No. 635813, 09, 12, 1977.). Materials having a chemical composition of Y ₃ Al ₅ O ₁₂ or (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ :Ce are widely used in high-speed cathode ray tube technology to detect black-and-white or color negative films. Scintillators based on powdered yttrium aluminum garnet or single crystal yttrium aluminum garnet are used in nuclear physics and nuclear technology. At the same time, the physical correction technique of the spectrum has also been applied. Therefore, it can be said that the main physical properties of YAG fluorescent materials, such as high luminous efficiency, broadband light emission in the cyan, green, yellow and orange wavelengths of visible light, the afterglow time is quite short, and the luminous flux and power stability are high, as early as Nichia has been known for using garnet phosphors for light-emitting diodes. Thus, the inventors believe that Nichia's research on garnet phosphors does not exceed the level of knowledge required to rationalize the use of phosphors for their immediate use. At the same time, it is completely unfounded to attribute all luminescent materials with 铈 as an active element to Nichia's patent authority. A large number of fluorescent materials well known, such as Al ₂ O ₃ :Ce, yttrium, lanthanum, cerium orthosilicate Y ₂ Si ₂ O ₅ :Ce, Gd ₂ SiO ₅ :Ce, Lu ₃ Si ₂ O ₇ : Ce, they are widely used in the production of fluorescent technology, and in life practice, they have nothing to do with the patented results of Nichia.

From the above analysis, the following conclusions can be drawn: 1. The technique of using phosphor powder and synergistic light-transfer powder for various types of light-emitting diodes has long been known; 2. By using two or more kinds of basic light phases The method for synthesizing white light has also been well known, and its physical and chromatic principles are very clear. 3. Fluorescent materials with yttrium aluminum garnet compound as the main component of yttrium have appeared as early as 1965. That is to say, far earlier than Nichia's invention; 4.Ce ⁺³ was used to start fluorescent materials with various crystal structures; and 5.Nichia's patented results on garnet phosphors are not innovative, but only A technical solution to the current specific problem: white light is obtained with blue base light.

Please refer to FIG. 1 , which is a schematic structural view of a conventional warm white light emitting diode. As shown in the figure, in line with the invention of Japanese engineer S. Schimzu, this light source contains the following components: nitride semiconductor heterojunction (PN junction) 1; wires 2, 3; derived from sapphire (Al ₂ O ₃ Or a thermally conductive substrate 4 of tantalum carbide (SiC); a reflective support 5; a luminescence conversion device 6 in the form of a polymer cover layer in which phosphor powder particles 7 are distributed; and a spherical or cylindrical lens The reticle 8 is in the form of a transparent polymer layer 9 present therein.

In fact, all white LEDs are repeating this slightly modified architecture, so this architecture is omnipotent.

Although this architecture has been widely used, it cannot be ignored that it also has some substantial shortcomings: the uneven thickness of the phosphor powder layer 7 in the polymer causes the luminance and luminescence of the light-emitting diode. The color is not uniform; there is a lack of a cover layer at the radiation edge of the nitride semiconductor heterojunction 1, resulting in a large amount of blue light radiation. At the same time, the color temperature of the light-emitting diode is very high Tc>8000K.

A number of researchers are working to remedy this shortcoming, as mentioned in U.S. Patent No. 7,071,616 (see U.S. Pat. This patent proposes a light-emitting diode with a lower color temperature, Tc≒3800~6000K. The solution to this technology is mainly the use of fluorescent powder specifically for orange-yellow light with a color coordinate of x>0.49 and y>0.44. This kind of light-emitting diode emits normal white light with a color temperature of Tc≒4200~4800K, which is characterized by a very high luminous intensity for 2θ=6°: I>100 candelas.

Although there are many advantages, but for normal color temperature and high luminous intensity

In other words, the known technical solution has a substantial disadvantage in that its color temperature and the color temperature of the incandescent light source are different, and the color temperature of the incandescent light source is 2850~4000K. From the moment when the incandescent lamp was invented 150 years ago, people's eyes began to get used to the warm white light source of this color temperature. The large amount of red light in the incandescent light source makes most of the objects around people in the house have a natural hue. In particular, this color is like the color of a human face. It looks very comfortable under the incandescent light source, but the color under the fluorescent light is not natural. It is a flaw in the world.

In order to solve the above disadvantages of the prior art, the main object of the present invention is to provide a warm white light emitting diode and a phosphor thereof which can reduce the amount of first order blue light emitted from the light emitting diode.

In order to solve the above disadvantages of the prior art, another object of the present invention is to provide a warm white light emitting diode and a phosphor thereof, which can create a semiconductor source emitting warm white light with a color temperature of 2000 ≦ Tc ≦ 5000K.

In order to solve the above-mentioned shortcomings of the prior art, another object of the present invention is to provide a warm white light emitting diode and a phosphor thereof which can create a brighter light source with a larger luminous flux.

In order to solve the above disadvantages of the prior art, another object of the present invention is to provide a warm white light emitting diode and a phosphor thereof which can create a warm white light emitting diode having high luminous efficacy.

In order to achieve the above object, a warm white light-emitting diode of the present invention is based on an indium gallium nitride heterojunction, and the composition thereof comprises a plurality of quantum wells having a polymerized luminescence conversion layer, characterized in that: The luminescent conversion layer is present in a uniform concentration. The luminescent surface and edge of the indium gallium nitride heterojunction are covered with a thermosetting polymer layer, and the luminescent conversion layer contains a plurality of phosphor particles, and the particles are at least two The layer of the layer of particles is present in the polymeric luminescence conversion layer to ensure partial transmission energy of 15 to 30% of the first order blue light radiation of the indium gallium nitride heterojunction, and 70 to 85% of the second level of orange yellow radiation .

In order to achieve the above object, a phosphor powder of the present invention is used in a warm white photodiode, which is based on an oxide of a main group I and III element of the periodic table, and an electron d layer and The element in the transition of the f layer acts as an activation element, and the matrix of the phosphor powder is composed of a solid solution of the same aluminate of lithium and lanthanum, and has a chemical formula of Li _a (Gd _1-x Y _x ) ₃ Al _5+a O _12+2a : TR; when the substrate is excited by a short-wave radiation, the ions of the element radiate yellow-orange light, and are mixed with short-wave radiation emitted by an indium gallium nitride semiconductor heterojunction to form warm white light.

For the above purposes, a warm white light diode of the present invention is composed of an indium gallium nitride heterojunction (InGaN) and a synergistic light-transfer powder, wherein the synergistic light-transfer powder is composed of a polymer. The base body and the phosphor powder are composed of an epoxy resin or an organic resin having a degree of polymerization of 100 to 500 and a molecular weight of more than 5,000 standard carbon units, and a phosphor powder having a weight ratio of 3 to 80% is filled therein, thereby A uniform thickness polymer layer is formed on the light-emitting surface of the heterojunction, which converts the original radiation of the short-wave heterojunction into warm white light with a color temperature of 2000 ≦ Tc ≦ 5000K.

In order to achieve the above object, a method for preparing a phosphor powder of the present invention comprises the steps of: solid-state sintering an oxide raw material with a carbonate; continuing for several hours in a high temperature environment; and burning at a high temperature in a reducing environment Burning stage.

To achieve the above object, a method of preparing a phosphor of the present invention comprises the steps of: using hydroxide as a raw material; and adding them in a suitable ratio to molten lithium hydroxide for thorough mixing.

First, the object of the present invention is to eliminate the disadvantages of the above-described warm white light emitting diode. In order to achieve this goal, the warm white light-emitting diode of the present invention has a structure similar to that described in FIG. 1, and therefore is not illustrated here, and is formed by using an indium gallium nitride heterojunction as a matrix. The invention comprises a plurality of quantum wells having a polymeric luminescence conversion layer, wherein the luminescent conversion layer is present in a uniform concentration, and the luminescent surface and edge of the indium gallium nitride heterojunction are covered with a thermosetting polymer layer. And the polymeric luminescence conversion layer contains a plurality of phosphor powder particles, and the particles are present in the polymerization luminescence conversion layer in the form of at least two layers of particles to ensure partial transmission energy reaches the first-order blue light of the indium gallium nitride heterojunction. 15 to 30% of radiation, 70 to 85% of second-grade orange radiation.

Wherein, the molecule of the thermosetting polymer layer is M>5000 carbon units.

The weight ratio of the phosphor powder particles is 3 to 80%.

The warm white light produced by the warm white light emitting diode has a color temperature from T=2000 to 5000K, and the efficiency is higher than 48 lm/w.

The invention provides a novel fluorescent powder and a synergistic light-converting powder based thereon, wherein the fluorescent powder is based on an oxide of a main group element of the periodic table I and III, and the df element is used as an active element, and has the following characteristics. The matrix of the phosphor powder is composed of a solid solution of the same aluminate of lithium and lanthanum, and the chemical formula is Li _a (Gd _1-x Y _x ) ₃ Al _5+a O _12+2a :TR, where 0<a≦ 1,0.1≦x≦0.5. The TR added to the above compound is an element f and a d element: Ce and/or Pr and/or Eu and/or Dy and/or Tb and/or Sm and/or Mn and/or Ti and/or Fe, which have Different degrees of oxidation between +2 and +4. When the matrix compound is excited by short-wave radiation of λ=490nm, the above ions will emit yellow-orange light with a wavelength of λ=540~610nm, which is emitted by the heterojunction of the indium gallium nitride semiconductor. The short-wave radiation phase is combined to form warm white light.

The physical chemistry of the present invention is as follows. First, the experiment of the present invention found that the aluminate of the Group I element has similar optical properties to lanthanum aluminate, such as a compound of the type MeAlO ₂ or M _e Al ₅ O ₈ . When these compounds are activated by Ce ⁺³ ions, they have strong luminescence properties and are excited by a light beam of λ=400 to 490 nm emitted from a blue LED.

The experiment of the present invention also found that the monoaluminate and polyaluminate of the Group I element form a solid solution with the Y ₃ Al ₅ O ₁₂ garnet type barium aluminate or the perovskite YAlO ₃ type barium aluminate. Its luminescent properties will be enhanced.

The solid solution of the aluminate of the Group I element with barium aluminate dissolves the bulky ions well, such as Ce ⁺³ . Pr ^{+ 3} which is a light rare earth element similar to Ce ^{+ 3} is also easily dissolved in the solid solution. Heavy rare earth ions such as Dy ⁺³ , Tb ⁺³ , Eu ⁺³ and Sm ⁺³ located at the junction of light/heavy rare earth elements are easily dissolved in the synthesized solid solution. At this time, Eu ⁺² and Sm ⁺² with variable valence states may have two different oxidation states: +2 and +3 valence, while Mn ⁺² and Mn ⁺⁴ , Ti ⁺³ and Ti ⁺⁴ , Fe ^{+ 2} and Fe ⁺³ may be present simultaneously or separately in the lattice structure of the solid solution. At this time, all of the above ions have strong luminosity. All of the above-mentioned strongly luminescent ions are excited to emit light in the near-ultraviolet (Dy ⁺³ , Tb ⁺³ , Mn ⁺⁴ , Ti ⁺³ ) or blue light band of λ = 440 nm in the visible light spectrum.

The use of a plurality of activating elements in the above novel compounds has the following advantages: 1. The wavelength band covered by the luminescent spectrum of the phosphor powder is wider than before; 2. The original luminescence can be changed or corrected by adding a small amount of the second or even the third activation element. Color; 3. The color of the phosphor powder can be changed by selecting excitation light of different frequencies.

In addition to the traditional activation element Ce ⁺³ , if the Ti ⁺³ and Fe ^{+3 are} dissolved in the phosphor powder matrix, the peak of the fluorescent powder radiation is increased by 125-130 nm, and the color coordinates at this time have orange-red characteristics: x=0.40, y=0.45.

The phosphor powder proposed by the present invention has several synthetic schemes. Referring to FIG. 2, a schematic flow chart of a method for preparing a fluorescent light according to a preferred embodiment of the present invention is shown. As shown, the method for producing phosphor of the present invention comprises the steps of: solid-state sintering an oxide raw material with a carbonate (step 1); for several hours in a high temperature environment (step 2); and in a reducing environment The high temperature is subjected to the burning phase (step 3).

In step 1, the oxide raw material and the carbonate are solid-sintered; wherein the oxide raw material is, for example but not limited to, Y ₂ O ₃ , Al ₂ O ₃ , Ce ₂ O ₃ , such as but not limited to Li ₂ CO ₃ .

In step 2, the high temperature environment is continued for several hours; wherein the high temperature environment is, for example but not limited to, 1000 to 1500 ° C, and lasts for example, but not limited to, 2 to 10 hours.

In step 3, the burning phase is performed at a high temperature in a reducing environment; wherein the high temperature environment is, for example but not limited to, 1100 to 1600 ° C, and continues for example, but not limited to, 2 to 10 hours, such as but not limited to It is H ₂ :N ₂ = 1:20.

Please refer to FIG. 3 , which is a schematic flow chart of a method for preparing a fluorescent light according to another preferred embodiment of the present invention. As shown, the method for preparing a phosphor of another preferred embodiment of the present invention comprises the steps of: using hydroxide as a raw material (step 1); and adding them to molten lithium hydroxide in an appropriate ratio. Mix well (Step 2).

In the step 1, the hydroxide is used as a raw material; wherein the hydroxide is, for example but not limited to, Al(OH) ₃ , Y(OH) ₃ or the like.

In step 2, they are added to the molten lithium hydroxide in an appropriate proportion and thoroughly mixed; wherein the phosphor powder synthesized by the chemical melting method is in the form of a homogeneous solid solution, and the same quality of higher luminescence can be obtained. Technical parameters of the product.

A specific embodiment and its preparation method are as follows:

First weigh the following raw materials

Y ₂ O ₃ : 13.15 g Al ₂ O ₃ : 26 g Gd ₂ O ₃ : 31.65 g Li ₂ CO ₃ : 0.37 g CeO ₂ : 1.55 g

The above raw materials were thoroughly mixed, placed in 300 ml of alumina crucible, and the crucible was placed in a furnace, and the temperature was raised to 1100 ° C at a heating rate of 5 ° C / min for 2 to 4 hours; then, the furnace was started with H ₂ :N. ₂ =1:20 weak reducing gas protection, then increase the temperature to 1580 ° C at 5 ° C / min for 2 to 6 hours, then naturally cool to room temperature, remove the product and grind to powder, with 0.1M HNO ₃ The solution was processed in a strong acid solution, and a 50 nm zinc ZnO.SiO ₂ film was coated on the surface of the phosphor powder.

The chemical formula for forming the phosphor powder is Li _0.1 [(Gd _0.6 Y _0.4 ) _0.97 Ce _0.03 ] ₃ Al _5.1 O _12.2 , and the excitation spectrum is shown in Fig. 4 .

Another specific embodiment and its preparation method are as follows:

First weigh the following raw materials

Y ₂ O ₃ : 6.58 g Al ₂ O ₃ : 26.52 g Gd ₂ O ₃ : 42.21 g Li ₂ CO ₃ : 0.74 g CeO ₂ : 1.55 g Pr ₇ O ₁₁ : 0.078 g

The above raw materials are thoroughly mixed, placed in 300 ml of alumina crucible, and the crucible is placed in a furnace, and the temperature is raised to 1050 ° C at a heating rate of 5 ° C / min for 2 to 3 hours; then the furnace is started with H ₂ : N ₂ =1:20 weak reducing gas protection, then increase the temperature to 1530 ° C at 5 ° C / min for 2 to 5 hours, then naturally cool to room temperature, remove the product and grind to powder, with 0.1M HNO ₃ is processed in a strong acid solution, and a 50 nm zinc ZnO.SiO ₂ film is coated on the surface of the phosphor powder.

The chemical formula for forming the phosphor powder is Li _0.2 [(Gd _0.8 Y _0.2 ) _0.9685 Ce _0.03 Pr _0.0015 ] ₃ Al _5.2 O _12.4 , and the excitation spectrum is shown in Fig. 5 .

The phosphor powder particles are conveniently made into a synergistic light-transfering powder. The device is made by uniformly filling the inside of the polymer film with phosphor particles. An epoxy resin or an organic germanium resin having a polymerization degree of 100 to 500 and a molecular weight of 5,000 to 10,000 standard carbon units is selected as the material of the polymer film. The polymer molecules are too large to withstand the effects of heat generation during operation of the light-emitting diode. The filling weight ratio of the phosphor powder particles in the synergistic light conversion powder structure is 3 to 80%, and the optimum weight ratio is 15 to 25%. At this time, the synergistic light conversion powder forms a thickness on all the light emitting surfaces of the heterojunction. A uniform cover layer having a geometric thickness between 50 and 200 μm, which varies with the change in the particle size of the flakes. The thickness of the synergistic light conversion powder is generally 80 to 120 μm.

A variety of solutions for making warm white light emitting diodes have been devised during the testing of the present invention. The technical parameters are as follows: luminous intensity I=100 cd, luminous efficiency η=50 lm/w. Compared with traditional garnet fluorescing powder, this new type of fluorinated powder has a higher color rendering index R=70 due to its wider luminescence spectrum, which is used to create a comfortable professional lighting illuminating diode.

In summary, the method for preparing the warm white light diode, the synergistic light conversion powder, the fluorescent powder and the fluorescent powder of the present invention applies a nitride heterojunction capable of radiating a plurality of color lights, including warm white light, The remarkable feature is that it exhibits strong yellow and yellow-orange color, high quantum luminescence rate and long-lasting luminescence time, so it can improve the shortcomings of the conventional warm white light diode and its luminescent powder production method.

While the invention has been described above by way of a preferred embodiment, 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 protection is subject to the definition of the scope of the patent application.

1. . . Nitride semiconductor heterojunction

2, 3. . . wire

4. . . Thermally conductive substrate

5. . . Reflective bracket

6. . . Luminous conversion device

7. . . Fluorescent powder particles

8. . . Mask

9. . . Transparent polymer layer

step 1. . . Solid state sintering of oxide raw materials and carbonates

Step 2. . . Sustained for several hours in a high temperature environment

Step 3. . . Burning stage at high temperature in a reducing environment

FIG. 1 is a schematic view showing the basic structure of a conventional warm white light emitting diode.

2 is a schematic view showing the flow of a method for preparing a phosphor powder according to a preferred embodiment of the present invention.

3 is a schematic view showing the flow of a method for preparing a phosphor powder according to another preferred embodiment of the present invention.

4 is an excitation spectrum diagram of a fluorescent powder having a chemical formula of Li _0.1 [(Gd _0.6 Y _0.4 ) _0.97 Ce _0.03 ] ₃ Al _5.1 O _12.2 .

Fig. 5 is a graph showing the excitation spectrum of the phosphor powder when the chemical formula is Li _0.2 [(Gd _0.8 Y _0.2 ) _0.9685 Ce _0.03 Pr _0.0015 ] ₃ Al _5.2 O _12.4 .

Claims (14)

A warm white light emitting diode composed of an indium gallium nitride heterojunction (InGaN) and a synergistic light conversion powder, wherein the synergistic light conversion powder is composed of a polymer matrix and a phosphor powder, thereby Forming a uniform thickness polymer layer on the light-emitting surface of the indium gallium nitride heterojunction, the polymer layer converting the original short-wave radiation of the indium gallium nitride heterojunction into warm white light, wherein the chemical formula of the phosphor powder Is Li _a (Gd _1-x Y _x ) ₃ Al _5+a O _12+2a :TR, wherein the stoichiometric parameter of the formula is 0<a≦1, 0.1≦x≦0.5, added to the above compound TR is an element of f and element d: Ce and / or Pr and / or Eu and / or Dy and / or Tb and / or Sm and / or Mn and / or Ti and / or Fe, they have between +2 ~ +4 Different degrees of oxidation. The warm white light emitting diode according to claim 1, wherein the polymer base is based on an epoxy resin or an organic resin having a polymerization degree of 100 to 500. The warm white light-emitting diode according to claim 1, wherein the polymer matrix is filled with a phosphor powder having a weight ratio of 3 to 80%. The warm white light emitting diode according to claim 1, wherein the warm white light has a color temperature of 2000 ≦ Tc ≦ 5000K. A warm white light emitting diode comprising an indium gallium nitride heterojunction as a matrix, the composition comprising a quantum well having a polymeric luminescence conversion layer, wherein the polymeric luminescence conversion layer is in a uniform concentration The light-emitting surface and the edge of the indium gallium nitride heterojunction are covered with a thermosetting polymer layer, and the polymeric luminescence conversion layer contains phosphor powder particles, and the particles are present in the form of at least two layers of particles in the polymerization conversion. In the layer, to ensure partial transmission energy reaches 15~30% of the first-order blue light radiation of the indium gallium nitride heterojunction, and 70~85% of the second-level orange yellow radiation, wherein the chemical formula of the fluorescent powder is Li _a ( Gd _1-x Y _x ) ₃ Al _5+a O _12+2a :TR, wherein the stoichiometric parameter of the chemical formula is 0<a≦1, 0.1≦x≦0.5, and the TR added to the above compound is the f element And d elements: Ce and / or Pr and / or Eu and / or Dy and / or Tb and / or Sm and / or Mn and / or Ti and / or Fe, they have a different degree of oxidation between +2 ~ +4 . The warm white light-emitting diode according to claim 5, wherein the polymerized luminescence conversion layer is filled with a phosphor powder having a weight ratio of 3 to 80%. The warm white light emitting diode according to claim 5, wherein the warm white light has a color temperature of 2000 ≦ Tc ≦ 5000K. A luminescent powder used in a warm white photodiode, which is based on an oxide of elements of the main group I and III of the periodic table, and an element which is transitioned by an electron d layer and a f layer as an active element And the matrix of the phosphor powder is composed of a solid solution of the same aluminate of lithium and lanthanum, and has a chemical formula of Li _a (Gd _1-x Y _x ) ₃ Al _5+a O _12+2a :TR, in the above compound The TR added is an element f and a d element: Ce and/or Pr and/or Eu and/or Dy and/or Tb and/or Sm and/or Mn and/or Ti and/or Fe, which have +2~ +4 different degrees of oxidation, and the stoichiometric parameter of the chemical formula is 0 < a ≦ 1, 0.1 ≦ x ≦ 0.5; when the substrate is excited by a short-wave radiation, the ions of the element will radiate yellow-orange light, and The short-wave radiation emitted by the indium gallium nitride semiconductor heterojunction is mixed to form warm white light. The phosphor powder according to claim 8, wherein the wavelength of the short wave is λ At 490 nm, the wavelength of the yellow-orange light is λ = 540 to 610 nm. The fluorescent powder according to claim 8, wherein the first main group element is a monoaluminate and a polyaluminate, and the Y ₃ Al ₅ O ₁₂ garnet type barium aluminate or calcium When the titanium ore YAlO ₃ type barium aluminate forms a solid solution, its luminescent properties are enhanced. The fluorescent powder according to claim 10, wherein the solid solution formed by the monoaluminate of the first main group element and the bismuth polyaluminate dissolves a relatively large ion, and the ion is Ce ⁺³ . Heavy rare earth element ions such as Pr ⁺³ , Dy ⁺³ , Tb ⁺³ , Eu ⁺³ and Sm ⁺³ located at the junction of light/heavy rare earth elements. The utility model relates to a synergistic light-transforming powder, which is composed of a polymer and a phosphor powder. The phosphor powder is based on an oxide of a main group element of the periodic table I and III, and the df element is used as an active element, and has the following characteristics: The matrix of the phosphor powder is composed of a solid solution of the same aluminate of lithium and lanthanum, and has a chemical formula of Li _a (Gd _1-x Y _x ) ₃ Al _5+a O _12+2a :TR, which is added to the above compound. TR is an element of f and element d: Ce and / or Pr and / or Eu and / or Dy and / or Tb and / or Sm and / or Mn and / or Ti and / or Fe, they have +2 ~ +4 Different degrees of oxidation, and the stoichiometric index of the chemical formula is 0 < a ≦ 1, 0.1 ≦ x ≦ 0.5, when the matrix compound is excited by short-wave radiation, the ion will emit yellow-orange light, and an indium nitride The short-wave radiation phase emitted by the gallium semiconductor heterojunction forms a warm white light. The synergistic light conversion powder according to claim 12, wherein the TR added to the matrix compound is an element f and a d element: Ce and/or Pr and/or Eu and/or Dy and/or Tb and/or Or Sm and / or Mn and / or Ti and / or Fe, they have a different degree of oxidation between +2 ~ +4. The synergistic light conversion powder as described in claim 12, wherein the wavelength of the short wave is λ At 490 nm, the wavelength of the yellow-orange light is λ = 540 to 610 nm.