KR20180131128A - Yellow phosphor and method of manufacturing the same - Google Patents

Abstract

Disclosed in one embodiment are a yellow fluorescent substance and a method for manufacturing the same. The yellow fluorescent substance simultaneously emits light in a ultraviolet wavelength band and light in a yellow light wavelength band and satisfies chemical formula 1, Y_((1-x-y)3)Al_5O_12 : Ce_x. In chemical formula 1, x satisfies a condition of 0.001 < x < 0.05 and y satisfies a condition of 0.001 < y < 0.02.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yellow phosphorescent material,

An embodiment relates to a yellow phosphor and a method of manufacturing the same.

A method of forming a white light emitting device by bonding a yellow phosphor (Y ₃ Al ₅ O ₁₂ ) to a blue light emitting diode has been studied as a white light emitting device. This method is a method in which light having a high excitation energy emitted from a high-intensity blue short-wavelength light emitting diode excites a yellow phosphor to emit light in a yellow region, thereby inducing white light emission as a whole

The yellow phosphor (Y ₃ Al ₅ O ₁₂ ) can be synthesized by doping Ce with YAG, but it is also doped with ions (Pr, etc.) emitting red light because of low color rendering property.

In recent years, many products that use sterilization and disinfection by using an ultraviolet light source have been introduced. Such an ultraviolet light source can be realized by using a light emitting diode that emits ultraviolet wavelength band. However, research on the phosphor technology that emits ultraviolet light by combining a blue light emitting diode and a phosphor has been limited.

Embodiments provide a yellow phosphor capable of emitting white light using an excitation wavelength of a blue light emitting diode and outputting ultraviolet light together, and a method of manufacturing the same.

The problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned here can be understood by those skilled in the art from the following description.

The yellow phosphor according to an embodiment of the present invention simultaneously emits light in the ultraviolet wavelength band and light in the yellow wavelength band, and satisfies the following formula (1).

[Chemical Formula 1]

Y _{(1-xy) 3} Al ₅ O ₁₂ : Ce _x , Pr _y

Here, x satisfies 0.001 < x < 0.05, and y satisfies 0.001 < y < 0.02.

The ultraviolet wavelength band may have a first emission peak at 300 nm to 350 nm and a second emission peak at 350 nm to 400 nm.

According to an embodiment of the present invention, there is provided a method of manufacturing a yellow phosphor, comprising: forming a coating layer formed by mixing Y ₂ O ₃ , CeO ₂ , and Pr ₆ O ₁₁ on a substrate including aluminum; And heating the substrate to form a phosphor film, wherein the phosphor film satisfies the following formula.

[Chemical Formula 1]

Y _{(1-xy) 3} Al ₅ O ₁₂ : Ce _x , Pr _y

Here, x satisfies 0.001 < x < 0.05, and y satisfies 0.001 < y < 0.02.

The ultraviolet wavelength band may have a first emission peak at 300 nm to 350 nm and a second emission peak at 350 nm to 400 nm.

Wherein the step of processing the surface of the substrate before the step of forming the coating layer comprises the steps of: immersing the substrate in a surface treatment solution at 300 DEG C for 10 minutes to etch the surface; The surface treatment solution may be mixed with H ₂ SO ₄ and H ₃ PO ₄ .

The forming of the film may be performed by filling the substrate in a pressure sintering furnace to form a vacuum, injecting nitrogen gas into the sintering furnace, and performing heat treatment at a pressure of 10 ^-4 to 10 ^-5 torr.

According to the embodiments, a white light and an ultraviolet light emitting device that can act as a light source by emitting white light and can generate a sterilizing effect by emitting ultraviolet light can be realized.

The various and advantageous advantages and effects of the present invention are not limited to the above description, and can be more easily understood in the course of describing a specific embodiment of the present invention.

1 is a graph illustrating emission spectra of a yellow phosphor according to an embodiment of the present invention, and FIG.
2 is a graph illustrating emission intensity of an ultraviolet region according to doping amounts of Ce and Pr of a yellow phosphor according to an embodiment of the present invention,
FIG. 3 is a graph showing the emission intensity of ultraviolet region according to doping amount of Ce of a yellow phosphor according to an embodiment of the present invention,
FIG. 4 is a graph illustrating the emission intensity of ultraviolet region according to the doping amount of Pr of the yellow phosphor according to an embodiment of the present invention,
5 is a flowchart of a method of manufacturing a phosphor film according to an embodiment of the present invention,
6A is a view showing a method of processing one surface of a substrate,
FIG. 6B is a graph showing the measurement of the light emission intensity when the substrate is surface-treated,
Fig. 7 is a modification of Fig. 6,
8 is a view showing a process of forming a coating layer on one surface of a substrate,
9 is a view showing a process in which aluminum is diffused when a substrate is heated,
10 is an emission spectrum according to the film synthesis temperature,
11 is an excitation spectrum according to the film synthesis temperature,
FIG. 12 is a view showing a process in which a phosphor film according to an embodiment of the present invention implements white light,
13 is a conceptual diagram of a light emitting device package according to an embodiment of the present invention.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

FIG. 1 is a graph of emission spectra of a yellow phosphor according to an embodiment of the present invention. FIG. 2 is a graph showing the emission intensity of ultraviolet region according to doping amounts of Ce and Pr of a yellow phosphor according to an embodiment of the present invention. FIG. 3 is a graph illustrating emission intensity of an ultraviolet region according to doping amount of Ce of a yellow phosphor according to an embodiment of the present invention, and FIG. 4 is a graph showing the emission intensity of a yellow phosphor according to an embodiment of the present invention. And the emission intensity of the ultraviolet region according to the doping amount of Pr.

Referring to FIG. 1, the phosphor according to an exemplary embodiment of the present invention may emit light in the ultraviolet wavelength band and light in the yellow wavelength band simultaneously by absorbing light in the blue wavelength band. That is, the phosphor can generate light of a shorter wavelength band than the excitation light. This up-conversion can result in high energy emissions from low-energy radiation. An increase in energy can be achieved by absorbing several (eg, two to three) photons per single emission photon.

The emission spectrum of the phosphor may have a first emission peak in an ultraviolet region of 300 nm to 350 nm and a second emission peak P2 in an ultraviolet region of 350 nm to 400 nm. Further, it may have a third emission peak at a wavelength range of 500 nm to 600 nm. The intensity of the third emission peak may be larger than that of the first emission peak P1 and the second emission peak P2. FIG. 1 is a diagram in which only the first emission peak P1 and the second emission peak P2 are increased by 30 times in order to facilitate understanding.

The phosphor according to an embodiment may satisfy the following formula (1).

[Chemical Formula 1]

Y _{(1-xy) 3} Al ₅ O ₁₂ : Ce _x , Pr _y

Here, x satisfies 0.001 < x < 0.05 and y satisfies 0.001 < y < 0.02.

Referring to FIG. 2 and FIG. 3, the emission intensity of the ultraviolet region may be different depending on the doping amount of Ce. As the doping concentration of Ce increases, the intensity of the second emission peak P2 gradually increases. However, it can be seen that when the doping amount of Ce is 5%, the first emission peak P1 and the second emission peak P2 are hardly observed. That is, if Ce is doped by 5% or more, light emission in the ultraviolet region may not be achieved. Therefore, the doping amount of Ce is preferably larger than 0.1% and smaller than 5%.

4, when the doping amount of Pr is 0.1%, the intensity of the first emission peak P1 and the intensity of the second emission peak P2 are weak, whereas when the doping amount of Pr is 1%, the first emission peak P1, And the second emission peak P2 are increased. However, it can be seen that when the doping amount of Pr is 2%, the first emission peak P1 decreases. Therefore, it can be seen that the doping amount of Pr is preferably larger than 0.1% and smaller than 2%.

FIG. 5 is a flow chart of a method of manufacturing a phosphor film according to an embodiment of the present invention. FIG. 6A is a view illustrating a method of processing one surface of a substrate, FIG. Fig. 7 is a variation of Fig. 6; Fig.

Referring to FIG. 5, a method of manufacturing a phosphor film according to an embodiment includes a step (S10) of processing one surface 11a of a substrate 11 including aluminum, a step cesium (Ce), and further comprising: praseodymium (Pr) is by heating the step (S20), and the substrate 11 for applying a mixture of yttria (Y ₂ O ₃₎ solution, drying the solution to form a film (S30 ).

Referring to FIG. 6A, the step of machining the first surface 11a of the substrate 11 can improve the light extraction efficiency by irregularly processing the first surface 11a of the substrate 11.

Various kinds of substrates 11 including aluminum can be applied to the substrate 11. Illustratively, the substrate 11 may be a sapphire (Al ₂ O ₃ ) substrate, but is not limited thereto. The substrate 11 may be an AlN or AlGaN substrate.

The thickness of the substrate 11 may be 300 [mu] m to 900 [mu] m. When the thickness of the substrate 11 is larger than 900 m, there is a problem that the substrate 11 is not heated sufficiently and diffusion of aluminum is lowered. When the thickness is smaller than 300 m, cracks are easily generated.

According to the embodiment, the one surface 11a of the substrate 11 can be processed by using the surface treatment solution. Since the sapphire substrate 11 is chemically stable and does not etch to ordinary acids or bases, a small number of specific etching solutions can be used.

Illustratively, the surface treatment solution is phosphoric acid (H ₃ PO _4), phosphoric acid and potassium hydroxide (KOH) mixture, vanadium pentoxide (V ₂ O _5), no beard _{(Na 2 B 4 O 7)} , sulfuric acid (H ₂ SO ₄ ), And sulfuric acid phosphoric acid mixed solution. In the following description, the solution is a mixture of phosphoric acid (H ₃ PO ₄ ) and sulfuric acid (H ₂ SO ₄ ) in a ratio of 3: 1.

Specifically, the substrate 11 can be etched by immersing the substrate 11 in a surface treatment solution containing H ₂ SO ₄ and H ₃ PO ₄ for 10 minutes. When the roughness of the one surface 11a increases, the diffusion of aluminum in the substrate 11 is promoted, and aluminum can be easily diffused into the yttria (Y ₂ O ₃ ) solution.

Further, the roughness of the one surface 11a increases, and the light loss of the film can be reduced. For example, if the interface between the substrate and the film is flat, the total internal reflection may cause the light emission to escape to the side, resulting in optical loss. However, according to the embodiment, since the irregularities are formed in the phosphor film through the surface treatment, the light extraction efficiency can be improved. Therefore, the light emission intensity can be improved.

Referring to FIG. 6B, when the film is formed after etching one surface 11a of the substrate 11, it can be confirmed that the light emission intensity is twice or more higher than that of the unetched film. This is because the light extraction efficiency is improved by the irregularities of the substrate 11.

Referring to FIG. 7, a plurality of holes 11b may be formed on one surface of the substrate 11. The plurality of holes 11b may have a diameter of 200 nm to 400 nm and a depth of 500 nm to 1000 nm. The distance between the plurality of holes 11b may be 400 nm to 500 nm. The intervals of the holes 11b may be irregular or regular.

The method of forming the plurality of holes 11b is not particularly limited. For example, the etching solution may contact the exposed portion using a mask to form the hole 11b, or a laser may be used to form the hole 11b.

Alternatively, an anodic oxidation process may be performed by applying a voltage of 150V to 200V for 1 hour to 2 hours using phosphoric acid as an electrolyte. A plurality of holes 11b can be formed through the anodic oxidation process (Anodic Aluminum Oxide (AAO)).

However, the method of processing the substrate 11 may be performed in various ways, not necessarily limited thereto. For example, a film may be produced using a patterned substrate (PSS). In addition, oxygen plasma treatment may be performed using a RF plasma at a vacuum of 10 ^-2 to 10 ^-3 torr for about 30 minutes to 60 minutes.

FIG. 8 is a view showing a process of forming a coating layer on one side of a substrate, and FIG. 9 is a view showing a process in which aluminum is diffused when a substrate is heated.

8, the step of applying a solution includes the step of applying a yttria (Y ₂ O ₃ ) solution in which cesium (Ce) and praseodymium (Pr) are mixed on a substrate (11) . The coating layer 12 can be prepared by mixing cesium powder (CeO ₂ ) and praseodymium (Pr ₆ O ₁₁ ) powder in a solvent in yttria (Y ₂ O ₃ ) powder. The solvent may be selected from various types of solvents in which yttria (Y ₂ O ₃ ) powder, cesium powder (CeO ₂ ), praseodymium (Pr ₆ O ₁₁ ) can be dissolved. Illustratively, the solvent may be toluene.

At this time, the doping amount of cesium and praseodymium in the phosphor film can be controlled by controlling the content of cesium (Ce) and praseodymium (Pr). Further, there is an advantage that the thickness of the final film can be freely adjusted by controlling the coating amount of the solution.

Referring to FIG. 9, in the step of forming a film, the phosphor film 13 may be manufactured by heating the substrate 11. When the substrate is heated, the aluminum of the substrate is diffused, and the film may have a composition of YAG: Ce, Pr.

Conventionally, Y ₂ O ₃ powder, Al ₂ O ₃ powder, CeO ₂ Powder and Pr ₆ O ₁₁ powder were synthesized to prepare a yellow phosphor having a composition of YAG: Ce, Pr, and a phosphor was formed by mixing phosphors with epoxy. However, such a phosphor resin is easily deteriorated by heat. Further, in order to produce a phosphor film, it is troublesome to carry out a film process again using the synthesized phosphor.

However, according to the embodiment, it is possible to easily produce a film by applying a solution containing a fluorescent substance to the substrate 11 and drying the solution.

In the heating method of the substrate, the substrate 11 is charged in a pressure sintering furnace to form a vacuum, nitrogen gas is injected into the sintering furnace to maintain a pressure of 10 ^-4 to 10 ^-5 torr, It can be heat treated with temperature. In this case, the temperature inside the substrate 11 rises and aluminum of the substrate 11 can be diffused into the film 13.

In this case, the coating layer is synthesized into the phosphor film 13 by thermal diffusion, and the AlN layer 11c can be formed on the other surface of the uncoated substrate 11. The AlN layer 11c has higher thermal conductivity than sapphire. By way of example, the thermal conductivity of sapphire is 40 W / mK while the thermal conductivity of AlN is 150 W / mK or more. Therefore, the heat applied to the phosphor film can be easily released to the outside through the AlN layer 11c. Therefore, the heat resistance of the film can be improved.

Fig. 10 shows the emission spectrum according to the film synthesis temperature, and Fig. 11 shows the excitation spectrum according to the film synthesis temperature.

10 and 11, it can be seen that the light emission intensity is greatly improved when the heating temperature of the substrate 11 is 1800 ° C as compared with the case where the heating temperature of the substrate 11 is lower than 1600 ° C. That is, when the heating temperature of the substrate 11 is lower than 1600 ° C, it can be confirmed that the aluminum of the substrate 11 is not diffused to the film. The maximum heating temperature is preferably less than 1900 占 폚. YAG phosphor has a melting point of about 1950 ° C, the phosphor may be melted when the heating temperature is higher than 1900 ° C. Therefore, the heating temperature may be preferably from 1650 캜 to 1900 캜. When the heating temperature is 1750 ° C to 1900 ° C, diffusion of aluminum can be made easier.

The phosphor film 13 according to the embodiment may not be peeled off after being formed on the substrate 11. That is, the substrate 11 can serve as a support member for the phosphor film 13. [

FIG. 12 is a view illustrating a process in which a phosphor film according to an embodiment of the present invention implements white light, and FIG. 13 is a conceptual diagram of a light emitting device package according to an embodiment of the present invention.

Referring to FIG. 12, the fluorescent structure 10 according to the embodiment can partially absorb the light L1 in the blue wavelength band emitted from the light emitting device 100 and convert the light L1 into light in the yellow wavelength band and light in the ultraviolet wavelength band. The light in the yellow wavelength range in which the fluorescent structure emits light and the light in the blue wavelength range of the light emitting device 100 are mixed to output the white light L2. In addition, ultraviolet ray sterilization can be performed by outputting light L3 having an ultraviolet wavelength range of 300 nm to 400 nm.

The fluorescent structure 10 according to the embodiment may include the phosphor film 13 and the substrate 11.

Various types of substrates including aluminum may be used for the substrate 11. [ Illustratively, the substrate 11 may be a sapphire (Al ₂ O ₃ ) substrate, but is not limited thereto. The substrate 11 may be an AlN or AlGaN substrate.

The phosphor film 13 may have a composition of YAG: Ce, Pr. The thickness of the phosphor film 13 is not particularly limited. The phosphor film 13 may have a thickness enough to absorb blue light and emit yellow light and ultraviolet light.

The irregularities 13a may be formed at the interface between the phosphor film 13 and the substrate 11. [ Therefore, the light incident from the light emitting device 100 can be emitted to the outside of the substrate 11 without total internal reflection. That is, the light extraction efficiency can be improved.

The light emitting device 100 may include a first conductive semiconductor layer 124, an active layer 126, and a second conductive semiconductor layer 127.

The first conductivity type semiconductor layer 124 may be formed of a compound semiconductor such as a group III-V or a group II-VI, and the first conductivity type semiconductor layer 124 may be formed of a compound semiconductor, 1 dopant may be doped. The first conductive semiconductor layer 124 may be a semiconductor material having a chemical formula of In _{x 1} Al _{y 1} Ga _{1 -x 1 -y1} N (0 _{? X1? 1} , 0 _{? Y1? 1} , 0? X1 + y1? For example, GaN, AlGaN, InGaN, InAlGaN, and the like. The first dopant may be an n-type dopant such as Si, Ge, Sn, Se, or Te. When the first dopant is an n-type dopant, the first conductivity type semiconductor layer 124 doped with the first dopant may be an n-type semiconductor layer.

The active layer 126 is a layer where electrons (or holes) injected through the first conductive type semiconductor layer 124 and holes (or electrons) injected through the second conductive type semiconductor layer 127 meet. The active layer 126 may transition to a low energy level as electrons and holes recombine, and may generate light having a wavelength corresponding thereto.

The active layer 126 may have any one of a single well structure, a multiple well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, Is not limited thereto.

The second conductive semiconductor layer 127 may be formed on the active layer 126 and may be formed of a compound semiconductor such as a group III-V or a II-VI group. In the second conductive semiconductor layer 127, The dopant can be doped. The second conductivity type semiconductor layer 127 may be a semiconductor material having a chemical formula of In _{x 5} Al _{y 2} Ga _{1 -x 5 -y2} N ( _{0 ? X5? 1, 0? Y2? 1} , 0? X5 + _y2? , AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the second dopant is a p-type dopant such as Mg, Zn, Ca, Sr, or Ba, the second conductivity type semiconductor layer 127 doped with the second dopant may be a p-type semiconductor layer.

Referring to Fig. 13, the light emitting device package according to the embodiment includes a body 1 having a cavity 1a, lead frames 2a and 2b disposed on the body 1, and lead frames 2a and 2b electrically A light emitting device 100 to be connected to the light emitting device 100, and a fluorescent structure 10 disposed on the light emitting device 100.

The body 1 may be made of a resin material and may include a cavity 1a for partially exposing the lead frames 2a and 2b.

The light emitting device 100 may be electrically connected to the lead frames 2a and 2b. Although the light emitting device 100 has a horizontal structure in which the first electrode 142 and the second electrode 146 are connected by wires, the structure of the light emitting device 100 may be variously modified. Illustratively, the light emitting device 100 may be a flip chip.

The first electrode 142 and the second electrode 146 may be formed of one selected from the group consisting of ITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tin oxide), IAZO (indium aluminum zinc oxide), IGZO ), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO ZnO, ZnO, IrOx, RuOx, NiO, RuOx / ITO, Ni / IrOx / Au or Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ru, Mg, Zn, Pt, Au, and Hf. However, the present invention is not limited to these materials.

The fluorescent structure 10 may include a phosphor film 13 and a substrate 11.

The phosphor film 13 may have a composition of YAG: Ce, Pr. The phosphor film 13 converts the light emitted from the light emitting device 100 into white light and outputs ultraviolet light.

Various types of substrates including aluminum may be used for the substrate 11. [ Illustratively, the substrate 11 may be a sapphire (Al ₂ O ₃ ) substrate, but is not limited thereto. The substrate 11 may be an AlN or AlGaN substrate. The substrate 11 may function as a transparent cover of the light emitting device 100 package. Therefore, the substrate 11 may preferably have a thickness of 300 mu m to 900 mu m so as to have sufficient light transmittance.

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 (6)

1. A yellow phosphor which emits light of ultraviolet wavelength band and light of yellow wavelength band simultaneously and satisfies the following formula (1).
[Chemical Formula 1]
Y _{(1-xy) 3} Al ₅ O ₁₂ : Ce _x , Pr _y
Here, x satisfies 0.001 < x < 0.05, and y satisfies 0.001 < y < 0.02.
The method according to claim 1,
Wherein the ultraviolet wavelength band has a first emission peak at 300 nm to 350 nm and a second emission peak at 350 nm to 400 nm.
Forming a coating layer formed by mixing Y ₂ O ₃ , CeO ₂ , and Pr ₆ O ₁₁ on a substrate containing aluminum;
And heating the substrate to form a phosphor film,
Wherein the phosphor film satisfies the following formula.
[Chemical Formula 1]
Y _{(1-xy) 3} Al ₅ O ₁₂ : Ce _x , Pr _y
Here, x satisfies 0.001 < x < 0.05, and y satisfies 0.001 < y < 0.02.
The method of claim 3,
Wherein the phosphor film has a first emission peak at a wavelength of 300 nm to 350 nm and a second emission peak at a wavelength of 350 nm to 400 nm.
The method of claim 3,
Further comprising machining the surface of the substrate prior to forming the coating layer,
Wherein the step of machining the surface of the substrate comprises:
The substrate was immersed in a surface treatment solution at 300 캜 for 10 minutes to etch the surface,
Wherein the surface treatment solution is a mixture of H ₂ SO ₄ and H ₃ PO ₄ .
The method of claim 3,
Wherein the forming of the film comprises:
The substrate is charged into a pressure sintering furnace to form a vacuum,
Nitrogen gas is injected into the sintering furnace and heat treatment is performed at a temperature of 1650 ° C to 1900 ° C under a pressure of 10 ^-4 to 10 ^-5 torr.

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