KR101496718B1 - Phosphor and light emitting device - Google Patents

Abstract

The garnet fluorescent material according to the embodiment is represented by the following formula.
[Chemical Formula]
(A, B, C) _{8- x} O ₁₂ : Ce
Wherein A comprises at least one element selected from the group consisting of Y, Lu, Tb, Gd, La and Sm, and C comprises at least one element selected from the group consisting of Al, Si, Ga and In; And B may be the same element as A or C. When B is one of the C elements, 5 < the molar sum of B and C is < 7, and B is the element A 1 <the number of moles of A and B <5.)

Description

[0001] PHOSPHOR AND LIGHT EMITTING DEVICE [0002]

An embodiment relates to a phosphor and a light emitting element.

[0003] Recently, a variety of methods for fabricating gallium nitride (GaN) -based light emitting diodes have been actively carried out in the world.

For example, there is a method in which the blue, green, and red light emitting diode chips are turned on at the same time to adjust the brightness of the light emitting diode so that variable color mixing is performed to show white color. In addition, And a method of lighting simultaneously.

However, in the above-described multi-chip type methods, the output of each chip changes according to the non-uniformity of the operating voltage and the ambient temperature for each chip, and the color coordinates are changed.

According to such a problem, currently, there is a method of applying a phosphor on a blue or near ultraviolet (UV) light emitting diode chip as a method using a phosphor. This method is advantageous in that the process is simpler and more economical than the multichip type method described above. In addition, in the method using the phosphor, a light source of a desired color can be manufactured more simply through variable color mixture of three colors by using a phosphor that emits blue, green, and red light.

However, since the method using the phosphor changes the primary light source from the light emitting element to the secondary light source of the phosphor, the brightness, the correlated color temperature (CCT) And Color Rendering Index (CRI).

At present, a light source is realized by a combination of a Ga (In) N light emitting diode which emits blue light mainly at about 460 nm and a YAG: Ce ^{3 +} fluorescent substance which emits yellow light.

In addition, although there are alkaline earth silicate phosphors using europium as an activator on the blue light emitting diode chip, these phosphors have a lower reliability than YAG: Ce ^{3 +} phosphors.

Accordingly, in recent years, a method using nitride phosphors has been developed to ensure higher reliability than the YAG: Ce ^{3 +} phosphor. For example, as a conventional nitride-based phosphor, there is a phosphor having a chemical formula of MAlSiN ₃ , M ₂ Si ₅ N ₈ , and MSi ₂ O ₂ N ₂ .

However, conventional nitride phosphors require a high-temperature and high-pressure synthesis process, which complicates the process and uses expensive nitride as a raw material.

Accordingly, it is an object of the present invention to provide a garnet fluorescent material having excellent passivity characteristics and reliability and being easy to manufacture.

The embodiments are to provide a garnet fluorescent material having excellent thermal characteristics and excellent reliability, a method for producing the same, and a light emitting device including the garnet fluorescent material.

The garnet fluorescent material according to the embodiment is represented by the following formula.

[Chemical Formula]

(A, B, C) _8-x O ₁₂ : Ce _x

Wherein A comprises at least one element selected from the group consisting of Y, Lu, Tb, Gd, La and Sm, and C comprises at least one element selected from the group consisting of Al, Si, Ga and In; And B may be the same element as A or C. When B is one of the C elements, 5 < the molar sum of B and C is < 7, and B is the element A 1 <the number of moles of A and B <5.)

According to an embodiment, a light emitting device includes a light emitting diode chip emitting light having an emission peak in a wavelength range of 380 nm to 500 nm; A substrate for supporting and electrically connecting the light emitting diode chip; A molding member for molding the light emitting diode chip; And a fluorescent material dispersed in the molding member and represented by the formula (A, B, C) _{8- x} O ₁₂ : Ce wherein A is Y, Lu, Tb, Gd, La, Sm, C contains at least one element of Al, Si, Ga, In, B is one of the elements of A or C, B is an element the same as A or C When the B is one of the C elements, 5 <the number of moles of B and C is 7, and 1 <A and the number of moles of B is 5 when B is one of the A elements. )

The embodiment can provide a novel phosphor and a light emitting device including the same.

Embodiments can provide a phosphor that can be manufactured at a low cost and a light emitting device including the same.

The embodiment can provide a light emitting element capable of emitting white light.

1 is a view illustrating a structure of a light emitting device according to an embodiment.
2 is a view illustrating another structure of a light emitting device according to an embodiment.
3 is an emission spectrum of the green phosphor according to Example 1. Fig.
Fig. 4 shows an X-ray diffraction pattern using the X-ray diffractometer of the green phosphor according to Example 1. Fig.
5 is an emission spectrum of the yellow phosphor according to Example 2. Fig.
Fig. 6 shows an X-ray diffraction pattern of the yellow phosphor according to Example 2 using an X-ray diffractometer. Fig.
7 is a luminescence spectrum of the green phosphor of Example 3. Fig.
FIG. 8 shows an X-ray diffraction pattern of the green phosphor according to Example 3 using an X-ray diffractometer. FIG.
9 is an emission spectrum of the yellow phosphor according to Example 4. Fig.
10 shows an X-ray diffraction pattern of the yellow phosphor according to Example 4 using an X-ray diffractometer.
11 is an emission spectrum of a green phosphor according to the activator concentration in Example 5. Fig.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

1 is a view illustrating the structure of a light emitting device.

1, the light emitting device includes an InGaN-based light emitting diode chip 110 that emits light having an emission peak in a wavelength range of 380 nm to 500 nm, preferably a wavelength range of 450 nm to 460 nm, A substrate 120 for supporting the light emitting diode chip 110 and reflecting the light emitted from the light emitting diode chip 110 in the upward direction and two electrically isolated light emitting diode chips 110 for providing power to the light emitting diode chip 110 A wire 140 electrically connecting the light emitting diode chip 110 and the two lead frames 130 and a colorless or colored light transmission molding A molding member 150 made of a resin, and a phosphor 151 dispersed entirely or partially in the molding member 150.

2 is a view illustrating another structure of the light emitting device.

2, the light emitting device includes an InGaN light emitting diode chip 110 that emits light having an emission peak in a wavelength range of 380 nm to 500 nm, preferably 450 nm to 460 nm, and a light emitting diode chip A substrate 120 for supporting the light emitting diode chip 110 and reflecting the light emitted from the light emitting diode chip 110 in an upward direction and two electrically isolated electrode layers 131 for supplying power to the light emitting diode chip 110, A wire 140 electrically connecting the light emitting diode chip 110 and the electrode layer 131 and a molding member 150 made of a colorless or colored light transmitting resin for molding the light emitting diode chip 110, And a phosphor 151 that is wholly or partly dispersed in the molding member 150.

In the light emitting device shown in FIG. 2, one wire 140 electrically connects the light emitting diode chip 110 and one electrode layer 131. The light emitting diode chip 110 is electrically connected to the other electrode layer 131 by being mounted thereon.

1 and 2, the light emitting device includes a light emitting diode chip 110 to which power is supplied and a phosphor 151 surrounding the light emitting diode chip 110, and the light emitting diode chip 110 are excited by the phosphor 151 to generate secondary light.

That is, the light emitting device according to the embodiment of the present invention includes a light source that emits light, a substrate that supports the light source, and a molding member that is molded around the light source.

The molding member may be at least one of an epoxy resin, a silicone resin, a urea resin, and an acrylic resin as the light transmitting resin. Further, the molding member may be formed as a single structure or a multiple structure.

Hereinafter, the phosphor included in the light emitting device will be described in detail.

Garnet system  Phosphors, Garnet system  A method of manufacturing a phosphor and Garnet system  Fabrication of Light Emitting Device Using Phosphor

Garnet system  Phosphor

1 and 2, the following phosphors may be used for the phosphor 151 surrounding the LED chip 110.

The phosphor is a garnet fluorescent material represented by the following formula.

[Chemical Formula]

(A, B, C) _8-x O ₁₂ : Ce _x

Wherein A comprises at least one element selected from the group consisting of Y, Lu, Tb, Gd, La and Sm, C contains at least one element selected from the group consisting of Al, Si, Ga and In, And B may be the same element as A or C. Further, when B is one of the C elements, the sum of the molar amounts of B and C may be more than 5 and less than 7. When the B is one of the A elements, the molar sum of A and B may be more than 1 and less than 5.

For example, in the above formula, A is Lu and B and C may be Al, wherein the molar sum of B and C may be 6 to 7. That is, the above formula may include Lu _{2 -x} Al ₆ O ₁₂ : Ce _x or Lu _{1 - x} Al ₇ O ₁₂ : Ce _x .

In addition, X may be about 0.001 &lt; X &lt; 0.5. When X is 0.001 or less or more than 0.5, light efficiency may be lowered.

In the above formula, the phosphor 151 is excited by the light emitted from the light source and emits secondary light having an emission peak in a wavelength range of about 490 nm to 590 nm according to the central wavelength of the light emitted from the light source. That is, the phosphor according to an embodiment may be a green phosphor or a yellow phosphor having an emission peak in a wavelength range of about 490 nm to 590 nm.

Garnet system  Method of manufacturing phosphor

The garnet fluorescent material is manufactured by the following process.

In the step of producing the garnet fluorescent material,

(a) at least one rare earth oxide and / or nitride selected from the group consisting of Y, Lu, Tb, Gd, La and Sm; At least one metal oxide and / or nitride selected from the group consisting of Al, Si, Ga and In; Oxides and / or nitrides and / or halides of Ce as an activator; And mixing the halogen element as a flux under a solvent to form a mixture;

(b) drying and firing the mixture obtained in step (a) to prepare a phosphor;

(c) pulverizing and classifying the phosphor; And

(d) washing the fluorescent substance that has undergone classification with a solvent to remove unreacted material.

At this time, the amount of each substance used in the step (a) may be suitably adjusted to the stoichiometric ratio satisfying the conditions of the formula (1) or the formula (2). In addition, the mixing may be a wet mixing, and at least one of ethanol, acetone, and distilled water may be used as a solvent for wet mixing. Although the kind of the flux is not particularly limited, preferably, the flux is a halogen compound such as NH ₄ F, NH ₄ Cl, BaF ₂ , AlF ₃ , LaF ₃ , etc., From about 0.1% to about 20% by weight.

The drying in the step (b) may be carried out at a temperature of about 30 ° C. to about 100 ° C. for about 30 minutes to about 48 minutes, and the firing may be performed in a reducing atmosphere of about 1000 ° C. to 1700 ° C. for about 1 hour to about It can be heat treated for 488 hours. The reducing atmosphere may be a mixed gas of hydrogen and nitrogen or a mixed gas of ammonia and nitrogen. When a mixed gas of hydrogen and nitrogen is employed as the synthesis atmosphere, hydrogen is mixed at about 2 vol% to about 30 vol% It is preferable to use nitrogen gas.

In the step (c), the phosphor obtained by heat treatment in a reducing atmosphere is pulverized and classified to obtain a phosphor powder of a predetermined size. Since the phosphor obtained in the step (b) is aggregated due to a high heat treatment temperature, the pulverization and classification step is required to obtain a powder having a desired brightness and size. In this case, the pulverization and classification may be performed by using a powder of about 25 탆 to about 32 탆.

Further, the phosphor obtained by heat treatment in the reducing atmosphere includes trace amounts of halogenated compounds and unreacted materials. When the halide and the unreacted material are not removed, there arises a problem that the luminous intensity and the moisture resistance are inferior when the phosphor is manufactured using the phosphor. Therefore, in the step (d), the phosphor obtained in the step (c) may be washed to remove unreacted material.

The step of removing the unreacted material may include ultrasonic cleaning using a solvent such as ethanol, acetone, or distilled water, followed by drying, but the present invention is not limited thereto.

Garnet  Specific example 1 of the method for producing a phosphor

About 2.71 g, about 2.18 g, and about 0.11 g each of Lu ₂ O ₃ , Al ₂ O ₃ and CeO ₂ were weighed, and BaF ₂ was weighed in an appropriate amount. After acetone was added, wet mixing was carried out using an appropriate amount of zirconia balls Hour.

Then, the mixed mixture was dried in an oven at about 80 DEG C for about 4 hours, and the dried mixture was filled in an alumina crucible and fired at about 1500 DEG C for about 3 hours. At this time, about 5% hydrogen and about 95% nitrogen were used as a mixed gas, and a mixed gas of about 100 L per minute was flowed.

Subsequently, the phosphor was pulverized when the heat treatment was completed. Since the pulverized phosphor contained unreacted material, it was ultrasonically washed in distilled water for 30 minutes and then dried.

After drying, the phosphor of a certain size using powders was classified to prepare a Lu ₂ Al ₆ O ₁₂ : Ce ³⁺ green phosphor.

The luminescence spectrum of the phosphor thus prepared was analyzed, and the X-ray diffraction pattern of the phosphor was analyzed using an X-ray diffractometer.

FIG. 3 is a view showing an emission spectrum of a light emitting device including a phosphor according to Example 1, and FIG. 4 is a diagram showing an X-ray diffraction pattern according to Example 1. FIG.

Referring to FIG. 3, it can be seen that the phosphor according to Example 1 is excited by a light emitting diode chip having an excitation wavelength of 450 nm and has an emission peak in a wavelength range of 490 nm to 590 nm.

Referring to FIG. 4, it can be seen that the phosphor according to Example 1 has a garnet crystal structure.

Garnet  Specific example 2 of the method for producing a phosphor

Approximately 2.01 g, about 2.85 g and about 0.14 g each of Y ₂ O ₃ , Al ₂ O ₃ and CeO ₂ were weighed, and BaF ₂ was weighed in an appropriate amount. After acetone was added, wet mixing was carried out using an appropriate amount of zirconia balls at about 1 Hour.

Then, the mixed mixture was dried in an oven at about 80 DEG C for about 4 hours, and the dried mixture was filled in an alumina crucible and fired at about 1500 DEG C for about 3 hours. At this time, about 5% hydrogen and about 95% nitrogen were used as a mixed gas, and a mixed gas of about 100 L per minute was flowed.

Subsequently, the phosphor was pulverized when the heat treatment was completed. Since the pulverized phosphor contained unreacted material, it was ultrasonically washed in distilled water for about 30 minutes and then dried.

After drying, the Y ₂ Al ₆ O ₁₂ : Ce ³⁺ green phosphor was prepared by classifying the phosphor of a certain size using powder.

The luminescence spectrum of the phosphor thus prepared was analyzed, and the X-ray diffraction pattern of the phosphor was analyzed using an X-ray diffractometer.

FIG. 5 is a diagram showing the emission spectrum of the light emitting device including the phosphor according to the second embodiment, and FIG. 6 is an X-ray diffraction pattern according to the second embodiment.

Referring to FIG. 5, it can be seen that the phosphor according to Example 2 is excited by a light emitting diode chip having an excitation wavelength of 450 nm and has an emission peak in a wavelength range of 490 nm to 590 nm.

Referring to FIG. 6, it can be seen that the phosphor according to Example 2 has a garnet crystal structure.

Garnet  Specific example 3 of the method for producing a phosphor

Approximately 3.90 g, about 1.02 g, and about 0.07 g of Lu ₂ O ₃ , Al ₂ O ₃ and CeO ₂ were respectively weighed and BaF ₂ was weighed in an appropriate amount. After acetone was added, wet mixing was carried out using an appropriate amount of zirconia balls Hour.

Then, the mixed mixture was dried in an oven at about 80 DEG C for about 4 hours, and the dried mixture was filled in an alumina crucible and fired at about 1500 DEG C for about 3 hours. At this time, about 5% hydrogen and about 95% nitrogen were used as a mixed gas, and a mixed gas of about 100 L per minute was flowed.

Subsequently, the phosphor was pulverized when the heat treatment was completed. Since the pulverized phosphor contained unreacted material, it was ultrasonically washed in distilled water for about 30 minutes and then dried.

After drying, the phosphor particles of a certain size were classified to prepare a Lu ₄ Al ₄ O ₁₂ : Ce ³⁺ green phosphor.

The luminescence spectrum of the phosphor thus prepared was analyzed, and the X-ray diffraction pattern of the phosphor was analyzed using an X-ray diffractometer.

FIG. 7 is a view showing an emission spectrum of a light emitting device including a phosphor according to Example 3, and FIG. 8 is a diagram showing an X-ray diffraction pattern according to Example 3. FIG.

Referring to FIG. 7, it can be seen that the phosphor according to Example 3 is excited by a light emitting diode chip having an excitation wavelength of 450 nm and has an emission peak in a wavelength range of 490 nm to 590 nm.

Referring to FIG. 8, it can be seen that the phosphor according to Example 3 has a garnet crystal structure.

Garnet  Specific example 4 of the method for producing the phosphor

About 2.95 g, about 0.95 g, about 1.04 g, about 0.08 g each of Lu ₂ O ₃ , Tb ₄ O ₇ , Al ₂ O ₃ and CeO ₂ were respectively weighed and BaF ₂ was weighed in an appropriate amount. After adding acetone, The wet mixing was performed using a ball for about 1 hour.

Then, the mixed mixture was dried in an oven at about 80 DEG C for about 4 hours, and the dried mixture was filled in an alumina crucible and fired at about 1500 DEG C for about 3 hours. At this time, about 5% hydrogen and about 95% nitrogen were used as a mixed gas, and a mixed gas of about 100 L per minute was flowed.

Subsequently, the phosphor was pulverized when the heat treatment was completed. Since the pulverized phosphor contained unreacted material, it was ultrasonically washed in distilled water for about 30 minutes and then dried.

After drying, the phosphor particles of a certain size were classified to prepare a Lu ₃ Tb ₁ Al ₄ O ₁₂ : Ce ³⁺ yellow phosphor.

The luminescence spectrum of the phosphor thus prepared was analyzed, and the X-ray diffraction pattern of the phosphor was analyzed using an X-ray diffractometer.

FIG. 9 is a diagram showing the emission spectrum of the light emitting device including the phosphor according to the fourth embodiment, and FIG. 10 is a diagram showing the X-ray diffraction pattern according to the fourth embodiment.

Referring to FIG. 9, it can be seen that the phosphor according to Example 4 is excited by a light emitting diode chip having an excitation wavelength of 450 nm and has an emission peak in a wavelength range of 490 nm to 590 nm.

Referring to FIG. 10, it can be seen that the phosphor according to Example 4 has a garnet crystal structure.

Garnet  Specific Example 5 of Phosphor Production Method

Lu ₂ O ₃ , Al ₂ O ₃ , CeO _2, and BaF ₂ ,

(1) about 2.83 g, about 2.18 g, about 0.001 g, about 0.2 g

(2) about 2.82 g, about 2.17 g, about 0.01 g, about 0.2 g

(3) about 1.08 g, about 0.88 g, about 0.05 g, about 0.08 g

(4) about 0.86 g, about 0.89 g, about 0.25 g, about 0.08 g

After the addition of acetone, the mixture was wet-mixed using an appropriate amount of zirconia balls for about 1 hour.

Then, the mixed mixture was dried in an oven at about 80 DEG C for about 4 hours, and the dried mixture was filled in an alumina crucible and fired at about 1500 DEG C for about 3 hours. At this time, about 5% hydrogen and about 95% nitrogen were used as a mixed gas, and a mixed gas of about 100 L per minute was flowed.

Subsequently, the phosphor was pulverized when the heat treatment was completed. Since the pulverized phosphor contained unreacted material, it was ultrasonically washed in distilled water for about 30 minutes and then dried.

After drying, the phosphor particles of a certain size were classified to prepare a Lu _2-x Al ₆ O ₁₂ : Ce ³⁺ _x yellow phosphor. At this time, the range of the active agent x was 0.001 &lt; x &amp;le; 0.5. Specifically, (1) is x = 0.001, (2) is x = 0.01, (3) is x = 0.1 and (4) is x = 0.5.

The emission spectra of each of the phosphors thus prepared were analyzed.

FIG. 11 shows the light emission spectrum of the phosphor prepared above. Referring to FIG. 11, the optical characteristic changes according to the molar concentration of the activator x. When x is less than 0.001 or more than 0.5, the light efficiency is decreased as shown in FIG. 11, and it can be seen that the phosphor can not be used as a phosphor.

The garnet fluorescent material according to the embodiment can emit light in a wide range ranging from yellow light to green light by changing the composition of materials used in the manufacturing process.

In addition, since the novel phosphor can be synthesized at low temperature and pressure and uses an inexpensive starting material, the phosphor can be synthesized at a lower cost.

In addition, the phosphor according to the embodiment of the present invention exhibits a high color rendering index and provides practical utility as an illumination light source in place of a backlight for a color LCD for a cellular phone, an LED lamp, an in-vehicle display LED for a train and a bus, or a fluorescent lamp .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (11)

A garnet fluorescent material represented by the following formula
[Chemical Formula]
(A, B, C) _8-x O ₁₂ : Ce _x
Wherein A comprises at least one element selected from the group consisting of Y, Lu, Tb, Gd, La and Sm, and C comprises at least one element selected from the group consisting of Al, Si, Ga and In; And B may be the same element as A or C. When B is one of the C elements, 5 < the molar sum of B and C is < 7, and B is the element A 1 < the molar sum of A and B < 5, and X is 0.001 &lt; X &lt; delete The method according to claim 1,
Wherein the garnet fluorescent material is a green fluorescent material or a yellow fluorescent material. The method according to claim 1,
The garnet fluorescent material emits light having an emission peak in a wavelength range of 490 nm to 590 nm. The method according to claim 1,
Wherein A is Lu, B and C are Al, wherein the molar sum of B and C is 6 to 7, 6. The method of claim 5,
Wherein the above formula includes Lu _{2 - x} Al ₆ O ₁₂ : Ce _x or Lu _{1 - x} Al ₇ O ₁₂ : Ce _x . The method according to claim 1,
The above formula includes Lu ₂ Al ₆ O ₁₂ : Ce ³⁺ , Y ₂ Al ₆ O ₁₂ : Ce ³⁺ or Lu ₄ Al ₄ O ₁₂ : Ce ³⁺ ,
Wherein the garnet fluorescent material comprises at least one of Lu ₂ Al ₆ O ₁₂ : Ce ³⁺ , Y ₂ Al ₆ O ₁₂ : Ce ^3+, and Lu ₄ Al ₄ O ₁₂ : Ce ³⁺ . A light emitting diode chip emitting light having an emission peak in a wavelength range of 380 nm to 500 nm;
A substrate for supporting and electrically connecting the light emitting diode chip;
A molding member for molding the light emitting diode chip; And
And a phosphor dispersed in the molding member and represented by the formula (A, B, C) _8-x O ₁₂ : Ce _x .
Wherein A comprises at least one element selected from the group consisting of Y, Lu, Tb, Gd, La and Sm, and C comprises at least one element selected from the group consisting of Al, Si, Ga and In; And B may be the same element as A or C. When B is one of the C elements, 5 < the molar sum of B and C is < 7, and B is the element A 1 < the molar sum of A and B < 5, and X is 0.001 &lt; X &lt; delete 9. The method of claim 8,
Wherein the phosphor is a green phosphor or a yellow phosphor. 9. The method of claim 8,
Wherein the phosphor emits light having an emission peak in a wavelength range of 490 nm to 590 nm.

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