TWI390015B - Warm white light emitting diodes and their bromide - Google Patents

Description

Warm white light emitting diode and its bromide fluorescent powder

The present invention relates to the field of electronic technology, and more particularly to a bromide fluorescent powder related to illumination technology broadly referred to as 'Solid State Lighting' and warm white light using the same. Light-emitting diode.

Semiconductor light sources based on indium gallium nitride (InGaN) heterostructure junctions (ie, P-N junctions) have gradually replaced various types of illumination sources such as fluorescent lamps and gas discharge lamps, making modern lighting technology more complete.

The semiconductor illumination architecture contains a large number of quantum well components, which substantially increases the effective luminescence conversion in semiconductor radiation, and can increase the conversion process of effective electroluminescence. The internal electric light conversion efficiency is 95~99%, and the external light extraction efficiency is greater than 40%.

The second highlight is that efficient internal parameters depend not only on the interaction of semiconductor heterostructure junction InGaN, special luminescence spectra and phosphor powder radiation, but are described in detail in the patent at www.espacenet.com.

First, it is pointed out that the combination of a nitride GaN semiconductor structure and Stokes phosphor powder is proposed by Nakamura Shoichi (please refer to S. Nakanura Blue laser Springer-Verlar Berlin 1997, which is not described in detail herein). The radiant radiance used, the maximum illuminating radiation is distributed in the visible spectrum, and can produce other hues of luminescence.

In particular, it is proposed to use the well-known material Y ₃ Al ₅ O ₁₂ (refer to SGBlasse Luminescent material. Amst. Berliu, 1997) in the quality of the Stokes phosphor powder for use in the package architecture. The well-known Nichia patent (see U.S. Patent No. 20071149914 to S. Schimizu et al.) utilizes blue light radiation and follows the seventeenth century Newton's complementary color law to obtain effective white light. Prior to this Japanese patent, the principle of physics of complementary colors was used, such as the combination of blue and yellow light on the image tube of a color television.

In the description of the above-mentioned US20071149914 patent application, it uses a heterostructure junction InGaN as a substrate. Although this technology is widely used, it still has a series of shortcomings: 1. It shows azure luminescence in the instrument; 2. It has a high color temperature radiation of T>6500K; 3. It is not high for optical parameters. Semiconductor radiation equipment; 4. Suspension polymer instability fluorescent powder has a median diameter d ₅₀ = 6 ~ 12 microns; and 5. The range of optical technical parameters of the white light emitting diode, in special fluorescent There is no replication in the powder synthesis process.

These main reasons are found in the WO 2008/051486 A1 patent application, the specific formula for describing the nanometer size of yttrium aluminum garnet: (Y, A) ₃ (Al, B) ₅ (O, C ) ₁₂ . Wherein A=Tb, Gd, La, Sr, Ba, Ca, Mg, the main ion I, B=Si, Ge, B, P, S, substituted ion Al and the like.

It must be pointed out that the chemical formula does not comply with the original patent, such as nitrogen ion N ^-3 and sulfur ion S ^-2 in the phosphor component. Similarly, in our previous patents, it was mentioned that F ^-1 ions and Si ⁺⁴ ions were added to the fluorite powder component of garnet (please refer to Sochchin N. et al. Republic of China invention patent 2495678, /2006/02/ 07), however, the disadvantage of this existence is solved in the WO 2008/051486 A1 patent application, the data of which is hereby incorporated by reference.

However, it still has shortcomings: 1 under blue light excitation, having a color temperature of 6500K or higher; 2 with respect to the emission efficiency of the phosphor is not high, because there is no added F ^-1 and Cl ions in the composition ^{-. 1} ion; 3. The garnet particle of nanometer is not highly stable, and the important blue light scattering on the yellow particle fluorescent powder is disclosed in the WO2008/051486 A1 patent application.

In order to solve the above-mentioned drawbacks of the prior art, the main object of the present invention is to provide a bromide fluorescent powder which can eliminate the deficiency of high color temperature of particles of known materials.

In order to solve the above disadvantages of the prior art, another object of the present invention is to provide a bromine Phosphate powder, which eliminates instability and lifetime in the instrument.

In order to solve the above disadvantages of the prior art, another object of the present invention is to provide a bromide fluorescent powder having a rare earth element garnet substrate which can be used for a warm red luminescent phosphor of a semiconductor 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 which creates a light emitting diode structure based on an InGaN semiconductor heterostructure junction.

In order to achieve the above object, a bromide phosphor powder of the present invention is based on a rare earth oxidized garnet element, characterized in that the phosphor powder is added with a bromide ion in the garnet composition, and the chemical equivalent formula of the composition is (ΣLn) ₃ Al ₂ [Al(O _1-x Br _2x ) ₄ ] ₃ , wherein ΣLn=Gd and/or Y and/or Lu and/or Dy and/or Ce and/or Pr.

In order to achieve the above object, a warm white light emitting diode of the present invention is based on an InGaN semiconductor heterostructure junction and coated with a luminescence conversion layer, wherein the luminescence conversion layer has the scope as claimed in the patent application. The phosphor powder component introduced in the item 1 and the elliptical particles as described in claim 7 of the patent application are distributed in a transparent polymer in combination with an organic tannin, and the atomic mass thereof is from M=15000 to 25000. Carbon unit.

First, the object of the present invention is to eliminate the above-mentioned drawbacks of the phosphor powder and the warm white light-emitting diode using the phosphor powder. In order to achieve the object, the rare earth bromide fluorescent powder of the present invention is based on rare earth oxidized garnet element, characterized in that the fluorescent powder is added with bromide ions in the garnet composition, and the chemical equivalent formula of the composition is (ΣLn) ₃ Al ₂ [Al(O _1-x Br _2x ) ₄ ] ₃ , wherein ΣLn=Gd and/or Y and/or Lu and/or Dy and/or Ce and/or Pr.

The atomic fraction of the phosphor powder composition mainly includes: 0.5 ≦ Gd / Σ Ln ≦ 0.95; 0.01 < Y / Σ Ln ≦ 0.5; 0.01 < Ce / Σ Ln ≦ 0.045; 0.0001 < Pr / Σ Ln ≦ 0.01; 0.001 < Lu / ΣLn≦0.03; 0.0001≦Dy/ΣLn≦0.01.

Wherein, the stoichiometric index is x=0.0001~0.05; the cubic lattice parameter value is a=12.1~12.6Å, and the maximum radiation wavelength λ=580~610nm in the orange-red light-emitting region of the spectrum, and the color coordinate x=0.46, y=0.532.

The excitation spectrum of the phosphor is located at a wavelength λ=400-490 nm on the sub-band.

Among them, when the Br content in the synthetic phosphor powder is increased, the wavelength of the luminescent radiation increases from λ = 580 to 610 nm.

Among them, when the temperature reached 85 ° C, the luminance of the light was 92% at room temperature of 25 ° C.

Wherein, when the Br component is increased or decreased in the introduced charge, the particles of the phosphor powder have a median diameter d ₅₀ = 0.6 to 2.75 μm and are elliptical.

Wherein, the hot processing may be further combined with the oxidizing rare earth element, wherein the hot working treatment is to add a gaseous state containing a degree of oxidation of Br ^-1 bromine in a 5% H ₂ + 95% N ₂ of the reducible gas, when the hot processing is performed The temperature is from T=800~1400°C, and Ce(BrO ₃ ) ₃ ‧9H ₂ O is used as the active component.

First of all, the present invention pertains to a yttrium-aluminum garnet group element, mainly a Gd ⁺³ ion in a cationic lattice, and is not a conventionally well-known garnet phosphor powder (refer to the above-mentioned conventional patent); Second, the additive material proposed by the present invention includes large-sized Br ^-1 ions. Third, the material proposed by the present invention belongs to bilinear garnet, and not only has conventional oxygen ions, but also constitutes an octahedron [AlO ₄ ], but in the same second ligand, Br ^-1 was added and introduced into the form of [AlO _4-x Br _2x ].

The difference in the phosphor powder proposed by the present invention is that the parameter of increasing the crystal lattice is from a = 12.1 to 12.16 Å. For the oxyfluoride (Y _1-x Lu _x ) ₃ Al ₂ [Al(O _1-y F _2y ) ₄ ] ₃ , the value is a=11.95~11.98Å.

Then, the phosphor powder component proposed by the present invention is characterized in that: a rare earth additive is added to the crystal lattice of the cation, and there are a total of five such additives, and all the additives are located in the active spectrum, such as The addition of Tb ⁺³ ions ensures sufficient extension of the spectral excitation, and the radiation spectrum is at +10 nm. The addition of strontium ion Lu ⁺³ ensures that the excitation spectrum of the short-wave displacement of the phosphor powder is Δ=-5 nm. Then the rare earth additive acts as an activator, and the conversion of the cerium ion Ce ⁺³ in the 5d ₂ component ensures that the main luminescent radiation is located at the wavelength λ=520~800nm. For the Pr ⁺³ ion, at the beginning of the introduction of 4f, the special independent narrow-band radiation region is from λ = 608 ~ 612nm, while strengthening the activator Ce ⁺³ .

It is emphasized herein that the optimum atomic ratio of each substance in the cationic lattice is, for example but not limited to: 0.5 ≦ Gd / Σ Ln ≦ 0.95; 0.01 < Y / Σ Ln ≦ 0.5; 0.01 < Ce / Σ Ln ≦ 0.045; 0.0001 < Pr / Σ Ln ≦ 0.01; 0.001 < Lu / Σ Ln ≦ 0.03; 0.0001 ≦ Dy / Σ Ln ≦ 0.01.

For the characteristics of phosphor powder like this, Y ₃ Al ₅ O ₁₂ -Gd ₃ Al ₅ O _{12 is} established for the wavelength shift of the well-known Y ₃ Al ₅ O ₁₂ :Ce standard mechanism through the curing reaction mode. Instead, when the erbium ion concentration reaches 40%, the wavelength shifts from λ = 540 nm to λ = 569 nm, and the displacement Δ = 29 nm. We have pointed out that when Br ^-1 ions are added, there is a significant displacement △=10 nm, which shows that Br ^-1 ions are very effective components at the wavelength of the fluorescent powder radiation, in addition to expanding the tradition. The conventional half-wave width λ _0.5 = 120~128 nm. In the asymmetric spectral plot, the maximum concentration of Br ^-1 is also located on the asymmetric Gaussian radiation profile in the alumina tetrahedron, where the red and orange luminescence fractions increase.

An unusual feature of the phosphors proposed by the present invention is that the combination of Pr ⁺³ and Ce ⁺³ and Dy ⁺³ in the matrix of the phosphor has an increased maximum radiation spectrum.

The phosphor powder proposed by the invention is characterized in that: the material of the phosphor powder is added with Br ^-1 ions as a matrix material from 0.0001 to 0.05 atomic fraction, and the Br ^-1 substitution replacement portion surrounds the tetrahedron. Aluminium oxide ion.

Br ^-1 ions enter the complex tetrahedral composition, and there are different sizes between oxygen ion O ^-2 (τ _O = 1.38~1.40Å) and Br ^-1 (τ _Br = 1.90Å).

The fluorescent powder proposed by the invention has the substantial advantage that the addition of Br ^-1 ions to the composition of the phosphor powder sensitizes the activator Ce ⁺³ ion, and the concentration of the activator Ce ⁺³ ion is small. some.

It is necessary to point out an important characteristic of Br ^-1 in the phosphor component proposed by the present invention, in which an effective electron filling occurs in the chemical formula changing the composition O ^-2[ ←→Br ^-1 . In the chemical formula, the substitution of O ^-2 = 2Br ^-1 has no different values in the ionic radius, because the proposed substitution of Ce ⁺⁴ in the stoichiometric formula replaces the Gd ⁺³ ion according to the formula Ce ⁺⁴ + Br ^-1 → (Ce _Gd ) ^o +(Br _O )`

The phosphor powder proposed by the present invention also exhibits an important property relating to the thermal stability of the phosphor powder. Generally, for the standard garnet luminescent phosphor to raise the temperature, the illuminance will decrease, but when the temperature of the phosphor of the present invention is increased to 75 ° C, the brightness produced is only reduced by 2 to 4%, when the temperature is increased to At T = 85 ° C, the resulting brightness is only reduced by 6 to 8%. Similar to such illumination with little degradation in brightness, the material can be used on medium electrical power as well as high power semiconductor instrumentation.

The phosphor powder proposed by the invention adopts a bit line diameter d ₅₀ = 4 to 8 μm among the dispersed components, and a bit line diameter d ₅₀ =1 2 μm for the phosphor powder component required for the automated production equipment.

Of course, similar luminescence used in such microparticles, the operation here changes the particle morphology (external morphology) of the phosphor, which reduces its efficiency and deteriorates its atomic arrangement, thus affecting its thermal stability. .

For the preparation of large luminous flux (F>500 lm), the absorption size of the heterostructure junction is larger than 1.5×1.5 mm, and the phosphor powder in the luminescent conversion layer is prepared to have the correct morphology, and the particles of the phosphor powder are compared. The bit line diameter is d ₅₀ = 12 to 16 μm, and besides, the phosphor powder particles should have d ₉₀ ≧ 20 μm.

All of the phosphor powder luminescent particles have the following forms: micro, medium and large, requiring precise phosphor synthesis mechanism for complex production.

For the synthetic phosphors of the present invention having micro and medium dispersion forms, this determines the dependence of the dispersion size of the medium particles on the amount of Br ^-1 ions (concentration) in the synthesis of phosphor particles in air. If the concentration of Br ^{-1 in the} composition is less than 0.5% by atomic fraction, then the median diameter d _{50 of the} particles is 3 to 4 microns. If the concentration of Br in the air increases to 1% or higher, the diameter of the bit line in the phosphor powder is reduced to 1.5 to 2.5 microns. However, it is assumed that the diameter of the particles and the concentration of the Br ^-1 component are synthesized in the air by the phosphor powder; the solubility of the Br ^{- 1} ion in the phosphor powder composition is proportional to the Br ^-1 in the atmosphere, and in the phosphor powder particles. When the Br ^-1 ion concentration is too high, that is, when the Br ^-1 concentration is always rising (τ = 1.90 Å), the Br ^-1 ion radius is too large, causing cracks in various extents of the phosphor powder, and the microparticles appear. (Please refer to Figure 4), with illustrations as an illustration.

Achieving such an advantage In the phosphor powder proposed by the present invention, the material is created to have an elliptical type of microparticles, d ₅₀ = 0.6 to 2.75 μm.

The diameter is reduced, and the synthesis of the independent Br ^-1 material in the furnace is added to prepare the phosphor powder.

All well-known phosphor powders with a garnet structure are generally ceramic or gel synthesis. Most of the initial ingredients are those of the oxide type Lu ₂ O ₃ , CeO ₂ , Al ₂ O _{3 ,} etc., and hydroxides can also be used. The same composition Lu(OH) ₃ , Ce(OH) ₃ , Al(OH) ₃ and the like. In the gel material technique, a substance composed of water and an alcohol solution of Y ₃ (NO ₃ ) ₃ ‧6H ₂ OAl(NO ₃ ) ₃ ‧9H ₂ O and the like is synthesized.

The novel synthetic phosphor technology framework proposed by the invention adopts a rare earth oxidizing component and an aluminum component in the initial reagent, like: Ce(BrO ₃ ) ₃ ‧9H ₂ O, and then calcined in a reducing gas.

By adding NBr ₃ and Br ₂ components, the ratio of bromine gas to nitrogen in the furnace is Br ₂ :H ₂ :N ₂ =0.1:4.9:95~1:4:95, and the furnace temperature is T=800~1300°C. Hold for 6~16 hours, remove the ingredients after cooling, and pickle with diluted acid solution (HCl, HNO ₃ , H ₃ PO _{4 ,} etc.).

The specific specific components of the phosphor powder proposed by the present invention are synthesized as described in Table 1.

Hereinafter, please refer to FIG. 1 to FIG. 5 together to explain the influence of the composition of the phosphor powder proposed by the present invention. 1 is a spectrum diagram of Sample 1 in Table 1; FIG. 2 is a spectrum diagram of Sample 2 in Table 1; FIG. 3 is a spectrum diagram of Sample 3 in Table 1; and FIG. 4 is a particle shape diagram of Sample 1 in Table 1. FIG. 5 is a schematic structural view of a light-emitting diode of the present invention.

As shown in FIG. 5, it is a schematic diagram showing the structure of a light-emitting diode made of the phosphor powder according to the present invention. Wherein, the light emitting diode comprises two pins 2, 3, an InGaN semiconductor heterostructure junction 4 (hereinafter referred to as a semiconductor heterostructure junction), a tapered hair The light 5 and the luminescence conversion layer 7 are formed by combining the phosphor particles 6 and a polymer (not shown), and the surface layer of the luminescent diode is further provided with a spherical optical lens 8. The interval for the exposed radiation output is between the spherical optical lens 8 and the transparent luminescence conversion layer 7 of the polymer.

The light-emitting diode using the phosphor powder proposed by the present invention starts to emit blue light having a light wavelength of λ = 455 nm at an additional voltage value of U = 3.0 to 3.9V. The amount of luminescence depends on the adhesion permeability, and the current passing through the semiconductor heterostructure junction 4 generally has a parameter of I=20-350 mA.

The blue light appears to interact with the phosphor particles 6 and is distributed on the polymer luminescence conversion layer 7, when the phosphor particles 6 emit orange-red light having λ=580 nm, which is emitted through the semiconductor heterostructure junction 4. The first-order blue light is combined with the luminescence conversion layer 7 to have an orange-yellow luminescence, and as a result, warm white luminescence is exhibited. Such illumination is distributed over all of the faces to assist in the conversion of the conical luminescence through the spherical optical lens 8.

The luminescence conversion layer 7 will be described in more detail below. The portion of the instrument is located on the surface of the semiconductor heterostructure junction 4 and is composed of two parts: a polymer light transmissive layer (not shown) and the phosphor powder particles 6 proposed by the present invention. In the polymeric film layer, the invention is tested in combination with different tissues: epoxy, acrylic acid and organic germanium polymers. It is pointed out that the best polymer is from tannin and has a molecular mass of M=15000~25000 carbon units.

It is also specified that the weight ratio of the phosphor particles 6 in the luminescence conversion layer 7 is 8 to 75%. This has a strong luminescence conversion layer 7 and the blue radiation again ensures the necessary warm white radiation.

On the substrate of the semiconductor heterostructure junction 4, a luminescence conversion layer 7 is provided, characterized in that the phosphor powder 6 in the luminescence conversion layer 7 is distributed in an optically transparent polymer based on ruthenium, having a molecule The mass M is 15,000 to 25,000 carbon units, and the weight ratio of the phosphor powder particles 6 in the luminescence conversion layer 7 is 8 to 75%.

The composition of the luminescence conversion layer 7 contains a professional dosing structure on the surface layer of the semiconductor heterostructure junction 4. Such a sample is selected from the polymer and the phosphor particles 6, and all of the radiation facets and end faces are covered with a uniform concentration of the polymer film layer. The ratio between the polymer component and the phosphor particles 6 is from 1 to 10. The optimum thickness of the luminescence conversion layer 7 is, for example but not limited to, 80 to 160 μm, while indicating that the luminescence conversion layer 7 should have an equal thickness.

This achievement achieved in light-emitting diodes is characterized in that, for light-emitting diodes having the same thickness form, the optimum skin thickness of the skin layer is, for example but not limited to, 80-160 microns.

The focus of the spherical optical lens 8 should be direct, and the center of the lens is connected to the main radiation surface of the semiconductor heterostructure junction 4, and the surface layer of the semiconductor heterostructure junction 4 and the hemispherical optical lens 8 are filled with optical transparency. The polymer (not shown) has a refractive index of n ≧ 1.45, which ensures high impact strength (durability) of the mechanical and light-emitting diodes.

The above-mentioned white light emitting diode is characterized in that its main radiation surface center is direct, combined with the spherical optical lens 8, the space of the spherical optical lens 8 and the transparent polymer filled in the surface layer of the luminescence conversion layer 7 It has a refractive index of n ≧ 1.45.

It has been pointed out above that the white light emitting diode of the present invention has a white and orange-yellow visible spectral region with warm white radiation, its color coordinates x=0.46±0.02, y=0.45±0.03, and blue light radiation from I=100~ 500cd, for 2θ=60°, the light-emitting diode has a current of 100~500mA, and the working voltage is U=3.0~3.9V.

The professional luminous technology changes the luminous flux of the light-emitting diode proposed by the present invention, and the excitation power is 1 watt, which is characterized in that the luminous flux is F=68-98 lumens when the power of the light-emitting diode is 1 watt. The color temperature of the luminescence spectrum is T=2500~4500K.

Although the present invention has been disclosed above in the preferred embodiments, it is not intended to limit the present invention. The invention is to be understood as being limited by the scope of the appended claims.

2, 3‧‧‧ feet

4‧‧‧Semiconductor heterostructure junction

5‧‧‧Cone glow

6‧‧‧Flame powder particles

7‧‧‧Light conversion layer

8‧‧‧Spherical optical lens

1 is a schematic view showing the spectrum of Sample 1 in Table 1.

2 is a schematic view showing the spectrum of Sample 2 in Table 1.

Figure 3 is a schematic view showing the spectrum of Sample 3 in Table 1.

Figure 4 is a schematic view showing the particle shape of Sample 1 in Table 1.

FIG. 5 is a schematic view showing the structure of the light emitting diode of the present invention.

2, 3‧‧‧ feet

4‧‧‧Semiconductor heterostructure junction

5‧‧‧Cone glow

6‧‧‧Flame powder particles

7‧‧‧Light conversion layer

8‧‧‧Spherical optical lens

Claims (10)

A bromide phosphor powder based on rare earth oxidized garnet element, characterized in that the phosphor powder is added with bromide ions in the garnet composition, and the chemical equivalent formula of the composition is (ΣLn) ₃ Al ₂ [Al(O _1-x Br _2x ) ₄ ] ₃ , wherein ΣLn=Gd and/or Y and/or Lu and/or Dy and/or Ce and/or Pr, wherein the stoichiometric index is x=0.0001~0.05. The bromide fluorescent powder according to claim 1, wherein the cubic lattice parameter value is a = 12.1 to 12.6 Å, and the maximum radiation wavelength λ = 580 to 610 nm in the orange-red light-emitting region of the spectrum, The color coordinates x=0.46, y=0.532. The bromide phosphor according to claim 1, wherein the excitation spectrum is located at a wavelength λ = 400 to 490 nm on the sub-band. The bromide fluorescent powder according to claim 1, wherein when the temperature reaches 85 ° C, the luminance of the light is 92% at room temperature of 25 ° C. A warm white light emitting diode based on an InGaN semiconductor heterostructure junction and coated with a luminescence conversion layer, wherein the luminescence conversion layer has fluorescence introduced as described in claim 1 In the powder component, the particles of the phosphor powder have a median diameter d ₅₀ = 0.6 to 2.75 μm and are elliptical, and the elliptical phosphor particles are distributed in a transparent polymer in combination with an organic tannin. The atomic mass is from M=15000 to 25000 carbon units. The warm white light emitting diode according to claim 5, wherein the weight ratio of the phosphor powder particles in the luminescence conversion layer is 8 to 75%. The warm white light emitting diode according to claim 5, wherein the luminescence conversion layer has a uniform thickness, and the radiation surface and the side surface have a thickness of 80 to 160 μm. The warm white light emitting diode according to claim 5, wherein the color coordinate value x=0.46±0.02, y=0.45±0.03 for the radiation located in the orange-red spectral region. A warm white light emitting diode as described in claim 5, wherein the electricity is When the power is 1 watt, the luminous flux is 68~98 lumens. For example, in the warm white light emitting diode described in claim 5, wherein the temperature of the heating casing reaches T=85 ° C, the color temperature is from 2500 to 4500K.