KR100658458B1 - Yellow-red phosphor, white LED using the phosphor and yellow-red LED using the phosphor - Google Patents

Abstract

The phosphor according to the present invention has a structure of the following formula (1).

(Ca _1-x Re _x ) ₂ Si ₉ Al ₃ N ₁₆ (1)

In which Re = Ce, Pr, Eu, Tb, Yb or Er, 0.01 ≦ x ≦ 0.75)

The phosphor according to the present invention can be used in high brightness yellow red LED devices, especially since it has high luminance emission characteristics by an excitation light source near 405 nm, and can be used in white LED devices having UV excitation light sources because they exhibit broadband emission spectrum. Can be. In addition, the white LED device manufactured according to the present invention has excellent color expression since the color rendering index is high.

Yellow red phosphor, white LED element

Description

Yellow-red phosphor, yellow LED and yellow red LED using the same {Yellow-red phosphor, white LED using the phosphor and yellow-red LED using the phosphor}

1 shows an emission spectrum of a white LED device using a conventional YAG phosphor.

2 shows a CIE chart of a white LED device using a conventional YAG phosphor.

3 is a schematic diagram of a shell type LED device according to the present invention.

4 is a schematic diagram of a surface mount type LED device of the PCB type according to the present invention.

5 is a schematic view of an epoxy lens type surface mounted LED device according to the present invention.

6 shows absorption spectra of the phosphors prepared in Examples 1 to 4 of the present invention.

7 shows emission spectra of the phosphors prepared in Examples 1 to 4 of the present invention.

8 shows absorption spectra and emission spectra of phosphors prepared in Examples 5 and 6 of the present invention.

9 shows light emission spectra of the white LED device manufactured according to Example 7 of the present invention.

<Description of the symbols for the main parts of the drawings>

1: anode wire 2: cathode wire

3: LED chip 4: anode lead

5: cathode lead 6: epoxy mold layer

7: epoxy lens 8: substrate

9: metal wire 10: molding mold

11: insulator 12: bonding material

The present invention relates to a phosphor, and more particularly, to a yellow red phosphor having excellent luminous efficiency in a UV excitation light source, a white LED device and a yellow red LED device using the same.

White LEDs using semiconductors have longer lifespans than incandescent bulbs (supplied 60W), can be miniaturized, and can be driven at low voltages. I am getting it.

As a method of manufacturing the white LED, there is a method of using all three color (red, green, blue) light emitting diodes, but the manufacturing cost is high and the size of the product is increased due to the complicated driving circuit, and the temperature of the three light emitting diodes is increased. Since the characteristics are different from each other, it may adversely affect the optical properties and reliability of the product.

In addition, a white LED in which a YAG-based fluorescent material is combined with an InGaN-based blue LED having a wavelength of 450 nm has been put to practical use, and part of the blue light generated from the blue LED excites the YAG-based fluorescent material to generate yellow-green fluorescence. Blue and yellow-green are combined to make white light. FIG. 1 shows an emission spectrum of a white LED device made of a blue light emitting diode + YAG phosphor, and FIG. 2 shows an area of white light appearing on a CIE chart. In FIG. 2, the B-LED represents a blue light emitting diode, and the Y-phosphor represents yellow, in which some blues are wavelength-converted by the YAG-based phosphor. White light moves along the connecting line between B-LED and Y-phosphor and is marked with W. As can be seen in FIG. 2, since the white light has only a part of the spectrum of the visible light region, color rendering is about 60-75, and color rendering is not proper, so it is not suitable for use as a general indoor lighting. In addition, when the excitation light source around 405nm is used, the efficiency of the chip is the best. The YAG-based phosphor is excited by the blue LED light of 450 to 460nm, and thus the efficiency is low. There is a problem in the uniformity and reproducibility of the mixing ratio.

In order to solve the problem of the blue LED + YAG-based phosphor, efforts are being actively made to develop a white LED that emits white near natural colors by using a UV LED as an excitation light source and combining all of red, green, and blue phosphors. In order to manufacture such a white LED, it is particularly necessary to develop a fluorescent material having excellent luminous efficiency at an excitation light source around 405 nm having the best chip efficiency. Currently, blue and green have satisfactory luminous efficiency, but the red fluorescent material has the worst characteristics, and the luminous efficiency is deteriorated at excitation wavelengths of 400 nm or more. Therefore, the use of white LEDs combining these R, G, and B phosphors is practical. It is becoming a problem.

The first technical problem to be achieved by the present invention is to solve the above problems and to provide a non-oxide-based phosphor that is excellent in luminous efficiency in a long wavelength UV excitation light source, and can be used in the manufacture of white LEDs.

The second technical problem to be achieved by the present invention is to provide a white LED including the phosphor.

The third technical problem to be achieved by the present invention is to provide a yellow-red LED comprising the phosphor.

The present invention provides a phosphor of the formula (1) to achieve the first technical problem.

(Ca _1-x Re _x ) ₂ Si ₉ Al ₃ N ₁₆

In which Re = Ce, Pr, Eu, Tb, Yb or Er, 0.01 ≦ x ≦ 0.75)

The present invention to achieve the second technical problem,

It provides a white LED device comprising a phosphor of the formula (1), manufactured using an excitation light source of 250 to 500nm wavelength band.

According to an embodiment of the present invention, the white LED device further includes a green phosphor as a phosphor, and the excitation light source may be a UV LED device having a wavelength range of 300 to 450 nm.

According to a preferred embodiment of the present invention, the white LED device further includes a green phosphor and a blue phosphor as phosphors, and the excitation light source may be a UV LED element having a wavelength range of 300 to 450 nm.

According to an embodiment of the present invention, the green phosphor may be a (Ba _1-x Sr _x ) SiO ₄ : Eu ²⁺ (0 ≦ x ≦ 1) series.

In addition, the blue phosphor may be (Sr _x (Mg, Ca) _1-x ) ₅ PO ₄ Cl: Eu ²⁺ (0 ≦ x ≦ 1).

The present invention provides a yellow-red LED device manufactured by using the phosphor and the UV LED device of 300 to 450nm wavelength band according to the formula (1) to achieve the third technical problem.

Hereinafter, the present invention will be described in more detail.

The phosphor according to the present invention exhibits an absorption spectrum in the wavelength range of 200-500 nm, which is a UV region, by using a silicon-silicon nitride compound as a parent, and is excellent in that it exhibits excellent luminous efficiency at a broad wavelength of 500-700 nm. When used in LEDs, the composition of the phosphor amount can be easily controlled and the uniformity and reproducibility can be improved. In addition, by adding Ce, Pr, Eu, Tb, Yb or Er to the parent compound can change the light emission characteristics and physical properties of the phosphor. The amount of Re added x is preferably from 0.01 to 0.75. When the x value is less than 0.01, the amount of the activator is small so that light emission does not occur, resulting in a decrease in luminance and a decrease in wavelength conversion efficiency of the phosphor. Rather, it is not preferable because there is a problem in that light disappears in the phosphor due to an excessively added active agent, resulting in a decrease in efficiency.

The method of preparing the phosphor of Chemical Formula 1 according to the present invention is not particularly limited, but may be a solid phase method, a liquid phase method, or a gas phase method, but when prepared by the solid phase method, silicon nitride, aluminum nitride, calcium nitride, Calcium chloride, calcium hydroxide, calcium carbonate, calcium oxide, nitrates of rare earth metals and oxides of rare earth metals are mixed and pulverized and dried. The dried material is subjected to a first heat treatment in a nitrogen atmosphere at 600 to 900 ° C., and then 1500. It can be prepared by secondary sintering in a nitrogen atmosphere containing at least 5% hydrogen at -1900 ℃. For example, when Eu is used as the rare earth metal, Eu (NO ₃ ) ₃ may be used as the nitrate of the rare earth metal, and Eu ₂ O ₃ may be used as the oxide of the rare earth metal. The reason why the sintering is divided into primary and secondary is to promote crystal growth while removing impurities such as water, organic substances or complex salts of some salts contained in the mixed raw materials in the region of 600 to 900 ° C. When the primary sintering temperature is less than 600 ℃, crystals are not well formed, and when it exceeds 900 ℃, unwanted unreacted substances can be formed in the mixed component, which interferes with the secondary phase sintering reaction, thereby improving wavelength conversion efficiency. When the secondary sintering temperature is lower than 1500 ℃, there is a problem that the synthesis reaction of the fluorescent material is not made properly, so that the desired emission intensity can not be obtained in the UV wavelength characteristics, when the second sintering temperature is higher than 1900 ℃ It dissolves at high temperature to form a glass phase, reducing the luminescence intensity and obtaining powder of desired physical properties. Because it is easy undesirable.

The white LED device according to the present invention uses a phosphor combination prepared by mixing a green phosphor with the phosphor of Chemical Formula 1, and may use a UV LED device having a wavelength band of 365 to 420 nm as an excitation light source. The green phosphor is not particularly limited, and there are aluminate-based compounds such as BaMgAl ₁₀ O ₁₇ : Mn ^2+, and chlorosilicate-based compounds such as Ca ₈ Mg (SiO ₄ ) Cl ₂ : Eu ²⁺ and Mn ^2+. It is preferable that the Ba _1-x Sr _x ) SiO ₄ : Eu ²⁺ (0 ≦ x ≦ 1) series. This is because the phosphor according to the present invention exhibits a maximum absorption spectrum in the wavelength region near about 390 to 405 nm, and therefore it is preferable to combine the green phosphor having the maximum absorption spectrum in this wavelength region.

According to a preferred embodiment of the present invention, the white LED device uses a phosphor combination including the phosphor of Chemical Formula 1 and a green phosphor and a blue phosphor as a phosphor, and the excitation light source is a UV LED element of 300 ~ 450nm wavelength band It may be used. The green phosphor is not particularly limited, BaMgAl ₁₀ O _17: aluminate-based, such as _{^{Mn 2+, Ca 8 Mg (SiO}} 4) Cl 2: Eu 2+, etc., but the chloro silicate-based, such as Mn ²⁺ ( Ba _1-x Sr _x ) SiO ₄ : Eu ²⁺ (0 ≦ x ≦ 1) is preferable, and the blue phosphor is not particularly limited, and BaMg ₂ Al ₁₆ O ₂₇ : Eu ²⁺ , BaMgAl ₁₀ O Although there are aluminates such as ₁₇ : Eu ²⁺ and the like, (Sr _x (Mg, Ca) _1-x ) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ (0 ≦ x ≦ 1) is preferable. As described above, when the phosphor according to the present invention is used in combination with the green phosphor and the blue phosphor, since the color rendering index is high as 80 or more, the color expression is excellent when used as illumination light and is close to natural light.

On the other hand, the white LED device according to the present invention may further improve the color rendering by using a small amount of the red phosphor further mixed in addition to the green phosphor and the blue phosphor, the red phosphor is not particularly limited as long as it is commonly used in the art Does not.

The LED device according to the present invention may have a shell type or a surface mount type as a conventional structure. A schematic view of the shell type LED device is shown in FIG. 3, and a surface mount type LED device of a PCB type is shown in FIG. 4. As shown in FIG. 3, the epoxy mold layer 6 including the phosphor prepared by Chemical Formula 1 is provided on the LED chip 3 having light emission characteristics in the range of 200 to 500 nm, which is a dispenser or a suitable coating method. It can be applied using. On the other hand, the LED chip 3 and the anode lead (anode lead, 4) and the cathode (cathod lead, 5) through the anode wire (anode wire, 1) and the cathode wire (cathod wire, 2) made of gold and Die-bonded. Gold wire bonding requires p- and n-type electrodes on the upper part of the device when using a sapphire substrate, and gold wire bonding is sufficient when using a SiC conductive substrate. The epoxy mold layer 6 is cured, and then the epoxy lens 7 is formed by molding into a transparent epoxy resin and encapsulated using a mold having a desired shape, and the final shell type is subjected to trimming and cutting of the lead frame. LEDs can be manufactured.

In the case of a PCB type surface mounted LED, the LED chip 3 having light emission characteristics in the range of 200 to 500 nm is die-bonded with the metal wire 9 of the PCB substrate 8 through a gold wire, and according to the present invention. The epoxy mold layer 6 containing the phosphor can be molded in a dispenser type, and can be solidified to produce a transfer mold type.

5 shows a schematic view of an epoxy lens type surface mount LED. The package has a metal wire 9 attached to the PCB substrate or the ceramic substrate 8 and the substrate 8 is separated by the insulator 11. The interior of the molding mold 10 is made of a reflective film coated with aluminum or silver, and serves to reflect upward the light emitted from the diode and to trap an appropriate amount of epoxy. The LED chip 3 having light emission characteristics in the range of 200 to 500 nm is flip-chip in the form of a flip chip, and die-bonded through a bonding material 12 such as a gold bumper or Au-Sn, and the phosphor according to the present invention is The epoxy mold layer 6 which contains is dispensed. In the above, a silicone gel may be used instead of epoxy, in which case the silicone gel prevents thermal stress from being transferred directly to the chip and adversely affects reliability, and prevents short circuit of the gold wire due to heat shrinkage or expansion. can do. In addition, by using a silicone gel having a refractive index higher than that of epoxy, it is possible to reduce the reflection at the interface of the light emitted from the diode to improve luminance. After the epoxy mold layer 6 is formed, an epoxy lens 7 is formed, which may vary in shape depending on the desired orientation angle.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments, but the present invention is not limited thereto.

Examples 1-4

(Ca _1-x Eu _x ) ₂ Si ₉ Al ₃ N ₁₆ Preparation of Phosphor

Mix the stoichiometric ratios of Si ₃ N ₄ , AlN, CaCl ₂ , Ca (OH) ₂ , CaCO ₃ , CaO, Eu (NO ₃ ) ₃ and Eu ₂ O ₃ as precursors of silicon, aluminum, calcium and europium A small amount of isopropanol solvent was added, followed by mixing for 5 hours using a ball mill filled with alumina balls, and the slurry was dried in a drier maintained at 80 ° C. After sieving and pulverizing the agglomerated powder in the alumina reaction vessel, the first heat treatment for 5 hours in a nitrogen atmosphere of 800 ℃, and then secondary sintering in a nitrogen atmosphere containing 5% hydrogen at 1500 ℃ and finally Washed with distilled water. At this time, the amount x of the active substance europium was changed from 0.3 to 0.75 as shown in Table 1 to prepare a phosphor.

Europium added amount (x) Example 1 0.3 Example 2 0.35 Example 3 0.6 Example 4 0.75

Test Example 1

Observation of Absorption Spectrum

Absorption spectra of the phosphors prepared in Examples 1 to 4 of the present invention were measured and the results are shown in FIG. 6. Looking at Figure 6 it can be seen that the absorption spectrum of the broadband over the wavelength range of 200 ~ 500nm and the maximum excitation wavelength in the vicinity of 310nm and 390nm. As can be seen from FIG. 6, the amount of europium added x, which shows the optimum excitation characteristic, was 0.3.

Test Example 2

Observation of the emission spectrum

For the phosphors prepared in Examples 1 to 4 of the present invention, the emission spectrum was measured at an excitation wavelength near 390 nm, and the results are shown in FIG. 7. As can be seen in FIG. 7, when x is 0.3, the greatest intensity is exhibited, and at higher concentrations, quenching occurs and light is reduced.

Examples 5-6

(Ca _1-x Pr _x ) ₂ Si ₉ Al ₃ N ₁₆ Preparation of Phosphor

As precursors of silicon, aluminum, calcium and praseodymium, Si ₃ N ₄ , AlN, CaCO ₃ , CaO, Ca ₃ N ₃ , Pr ₂ O ₃ , Pr (OH) ₃ are mixed in a stoichiometric ratio and a small amount of isopropanol solvent After the addition, the mixture was mixed for 5 hours using a ball mill filled with alumina balls, and the slurry was dried in a drier maintained at 80 ° C. After sieving and pulverizing the agglomerated powder in the alumina reaction vessel, the first heat treatment for 5 hours in a nitrogen atmosphere of 800 ℃, and then secondary sintering in a nitrogen atmosphere containing 5% hydrogen at 1500 ℃ and finally Washed with distilled water. At this time, the amount of the active substance praseodymium x was 0.1 and 0.2 to prepare a phosphor.

Test Example 3

Observation of Absorption Spectrum and Luminescence Spectrum

Absorption spectra and emission spectra of the phosphors prepared in Examples 5 and 6 of the present invention were measured and shown in FIG. 8. Referring to FIG. 8, it can be seen that the maximum excitation wavelength is around 390 nm, and the case of Example 5 in which the amount of Pr added x is 0.1 is superior to the case in which the amount of Pr added x is 0.2 than the case where the amount of Pr added x is 0.2.

Example 7

Fabrication of White LED Devices

(Ba _1-x Sr _x ) SiO ₄ : Eu ²⁺ was used as the phosphor prepared in Example 1 and the green phosphor, and a UV type having a conventional structure as shown in FIG. 3 using UV LED as the excitation light source. A white LED device was manufactured and its emission spectrum is shown in FIG. 9. The color rendering index measured from the above result was 82, which showed that the color rendering index was superior to that of the white LED using the conventional YAG phosphor.

As described above, the phosphor according to the present invention can be used for a high luminance yellow-red LED device because it has a high luminance light emission characteristic by an excitation light source near 405 nm, and has a white light having a UV excitation light source because it exhibits a broadband emission spectrum. It can be used in white LED devices employing LEDs and blue LEDs as excitation light sources. In addition, the white LED device manufactured according to the present invention has excellent color expression since the color rendering index is high.

Claims (7)

A phosphor in which Re is substituted for Ca as a phosphor of Formula 1 below. (Ca _1-x Re _x ) ₂ Si ₉ Al ₃ N ₁₆ (1) In which Re = Ce, Pr, Eu, Tb, Yb or Er, 0.01 ≦ x ≦ 0.75) A white LED device comprising the phosphor of claim 1 and manufactured using an excitation light source having a wavelength band of 250 to 500 nm. 3. The white LED device of claim 2, further comprising a green phosphor, wherein the excitation light source is a UV LED device having a wavelength range of 300 to 450 nm. 3. The white LED device of claim 2, further comprising a green phosphor and a blue phosphor, wherein the excitation light source is a UV LED device having a wavelength band of 300 to 450 nm. The white LED device according to claim 3 or 4, wherein the green phosphor is (Ba _1-x Sr _x ) SiO ₄ : Eu ²⁺ (0 ≦ x ≦ 1). The white LED device of claim 4, wherein the blue phosphor is (Sr _x (Mg, Ca) _1-x ) ₅ (PO ₄ ) ₃ Cl: Eu ²⁺ (0 ≦ x ≦ 1). A yellow red LED device manufactured using the phosphor of claim 1 and a UV LED device having a wavelength band of 300 to 450 nm.

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