KR20080112163A - Phosphor, light emitting device and manufacturing method of phosphor - Google Patents

Abstract

A phosphor, a light emitting device and a fabricating method of phosphor are provided to improve morphology and luminescent brightness while generating a little residue and to control a correlated color temperature, color coordinate and color rendering index. A light emitting device(100) comprises a light source(130); a housing unit(120) supporting the light source; a light-transmitting member(160) formed in at least, the partial domain of the light source circumference; the first phosphor expressed as the chemical formula: Ba4-xMgySrzSi2O8:Eu^2+x (0<x<=1, 1<y<5, 2<z<5) mixed into the light-transmitting member; and the second phosphor emitting the light having a peak wavelength in a wavelength range of 580~640nm excited with the light emitted in the light source.

Description

Phosphor, light emitting device and manufacturing method of phosphor

The present invention relates to a phosphor, a light emitting element and a method for producing the phosphor.

Recently, the manufacturing method of white light emitting diode (LED), which is actively progressing around the world, is a method of obtaining a white by placing fluorescent material around a blue or UV LED chip in the form of a single LED chip and in the form of a multi-LED chip. There are two main ways to combine white or three LED chips into each other to get white.

A typical method of implementing white light emitting diodes in the form of multi-LED chips is to manufacture a combination of three LED chips of R, G, and B. The output of each LED chip according to the nonuniformity of operating voltage and ambient temperature for each LED chip. This change causes color problems such as different color coordinates.

Due to the above problems, the multi-LED chip form is suitable for a special lighting purpose that requires the production of various colors by adjusting the brightness of each LED through the circuit configuration rather than the implementation of a white light emitting diode.

Therefore, as a method of implementing a white light emitting diode, a binary system, which is a combination of a blue light emitting LED which is relatively easy to manufacture and has high efficiency and a phosphor which is excited by the blue light emitting LED and emits yellow light, is typically used. .

In a binary system, an yttrium aluminum garnet (YAG) phosphor, i.e., a YAG: Ce phosphor, using a blue LED as an excitation light source and Ce ³⁺ as a activator of rare earth trivalent ions as an activator is emitted from the blue LED. For example, a white light emitting diode having a form of being excited by excitation light may be used.

In addition, a light emitting device may be implemented using a green light emitting silicate-based phosphor, and a green phosphor having a chemical formula of A ₂ SiO ₄ : Eu ²⁺ is usually used using Eu ²⁺ ions as an activator (“A of the above formula”). "Means two or more compounds such as" Sr "," Ba "," Ca "," Mg ", and other ions other than Eu ²⁺ may be co-doping).

However, in the case of the conventional green light emitting phosphor, a large amount of residues are generated during the heat treatment process, and fluorescent particles are synthesized in an irregular size, such that luminance is degraded due to coarse morphology (Morphology). When ions are doped in a heat treatment environment, there is also a problem that the brightness is lowered.

The present invention provides a phosphor in which the luminescence brightness is improved.

The present invention provides a method for producing a phosphor in which fewer residues are produced in the process and morphology is improved to improve luminescence brightness.

The present invention provides a semiconductor light emitting device in which the emission luminance is improved and the control of the correlated color temperature, color coordinates and color rendering index is easy by combining the green phosphor or one or more phosphors including the green phosphor and one or more light sources.

Phosphor according to the embodiment is represented by the formula Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (where 0 <x ≦ 1, 1 <y <5, 2 <z <5) .

The light emitting device according to the embodiment includes a light source; A housing part supporting the light source; A light transmitting member formed in at least a portion of the area around the light source; And Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (wherein 0 <x ≦ 1, 1 <y <5, 2 <z <5), which is incorporated into the light transmitting member. Included phosphors are included.

The light emitting device according to the embodiment includes a light source; A housing part supporting the light source; A light transmitting member formed in at least a portion of the area around the light source; And Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (wherein 0 <x ≦ 1, 1 <y <5, 2 <z <5), which is incorporated into the light transmitting member. The first phosphor to be represented and the second phosphor is excited by the light emitted from the light source to emit light having a central wavelength in the wavelength range of 580 ~ 640nm.

The light emitting device according to the embodiment includes a first light source and a second light source; A housing part supporting the first light source and the second light source; A light transmitting member formed in at least a portion of the area around the first light source and the second light source; And Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (wherein 0 <x ≦ 1, 1 <y <5, 2 <z <5), which is incorporated into the light transmitting member. Included phosphors are included.

Embodiment of the present invention has the effect of improving the luminescence brightness of the phosphor by using the europium activated with Si ₂ O ₈ and by synthesizing the compound through the appropriate composition ratio of elements such as barium, strontium, magnesium.

According to the method of manufacturing a phosphor according to an embodiment of the present invention, since the residue is reduced in the process by providing an appropriate ratio of oxidizing gas and reducing gas and an optimized temperature environment, regular fluorescent particles having a constant size can be synthesized. There is an effect that the morphology is improved.

According to the light emitting device according to the embodiment of the present invention, by combining one or more phosphors and one or more light sources including green phosphors, the light emission luminance is improved and control of the correlated color temperature, color coordinates and color rendering index is easy.

In the description of an embodiment according to the present invention, each layer (film), region, pattern or structure may be "on" or "under" the substrate, each layer (film), region, pad or pattern. In the case of being described as being formed "in", "on" and "under" include both "directly" or "indirectly" formed. In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

Hereinafter, a phosphor, a light emitting device, and a method of manufacturing the phosphor according to the embodiment will be described in detail with reference to the accompanying drawings.

The phosphor according to the present invention is a green light emitting phosphor that is incorporated into the light transmitting member of the light emitting device, and is used as strontium (Sr), magnesium (Mg), barium (Ba), silica polymer (Si ₂ O ₈ ), and an activator. Europium (Europium oxide) is formed in the ratio of the formula (1).

Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (0 <x ≦ 1, 1 <y <5, 2 <z <5)

Phosphor having the chemical composition ratio of the light emission becomes a main peak depending on the x value of the Eu ²⁺ _x, the x value of the Eu ²⁺ _x can be 1 or less is greater than zero. As an example, in the phosphor according to the present invention, the x value of Eu ²⁺ _x may be in the range of 0.01 to 0.1.

1 is a diagram illustrating an emission spectrum according to a change in x value of Eu ²⁺ _x of a phosphor according to an exemplary embodiment of the present invention.

Excitation light used to measure the spectrum shown in Figure 1 is a light having a main emission peak in the wavelength range of 430 ~ 480nm, Figure 1 shows that the x value of Eu ²⁺ _x in the phosphor is 0.01, 0.05, 0.075, 0.1 indicates the intensity of light for each wavelength according to each x value.

Referring to FIG. 1, a phosphor having a chemical composition ratio of Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (0 <x ≦ 1, 1 <y <5, 2 <z <5) is Eu. ^The emission main peak changes with the change of the x value of ²⁺ _x and has the emission main peak in the 500 to 550 nm region (green region).

The first graph 1 of FIG. 1 is an emission spectrum when the x value of Eu ²⁺ _x is 0.01, and the second graph 2 is an emission spectrum when the x value of Eu ²⁺ _x is 0.05. 3 graph 3 is an emission spectrum when the x value of Eu ²⁺ _x is 0.075. The fourth graph 4 is an emission spectrum when the x value of Eu ²⁺ _x is 0.1. The larger the x value of Eu ²⁺ _x , that is, the first graph 1 to the fourth graph 4. Towards, it can be seen that the wavelength is formed long.

The light emitted by the phosphor having the above characteristics may be used in a semiconductor light emitting device by synthesizing with near-ultraviolet light or blue light used as excitation light to represent green or pastel tone light. And according to the said experimental measurement, it turns out that the x value of Eu2 ⁺ _x suitable for obtaining high brightness | luminance is the range of 0.01-0.1 as mentioned above.

Hereinafter, the phosphor will be described in more detail together with the production method thereof.

2 is a flowchart illustrating a method of manufacturing a phosphor according to an embodiment of the present invention.

For the first time, oxygen compounds of rare earth metals, especially oxygen compounds of europium and oxygen compounds comprising strontium (Sr), magnesium (Mg), barium (Ba) and silica polymers (Si ₂ O ₈ ) are Ba _4-x. Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (0 <x ≦ 1, 1 <y <5, 2 <z <5) is introduced into the mixing apparatus at a chemical composition ratio (S100).

Subsequently, the oxygen compounds are mixed (S110), for example, may be mixed by a mechanical method such as ball milling or blending in a high speed blender, a ribbon blender, distilled water, alcohol and acetone, etc. It may be mixed using a small amount of the solvent.

Next, the mixture is dried at 100 ~ 400 ℃ (S120). In this case, if the drying temperature is less than 100 ° C., the solvent does not evaporate, and if it exceeds 400 ° C., the reaction may be performed by itself.

Once the mixture is dried, selectively adding fluxing compounds such as borides, chlorides, fluorides and the like into the mixture in an amount sufficient to act as flux (S130), and then the mixture is silicate containing europium activated with rare earths. The heat treatment process is performed so as to be converted into the fluorescent material.

The phosphor may be heat-treated under reducing conditions or heat-treating under reducing conditions, and then heat-treating under reducing conditions. In an embodiment of the present invention, the phosphor is primarily heat-treated under oxidizing conditions and secondly heat-treated under reducing conditions.

First, in a temperature environment of 1100 to 1300 ° C. and in an air or oxygen gas supply state, the mixture is heated for 1 to 5 hours to perform an oxidative heat treatment (S140).

After the oxidation heat treatment, the mixture is heated for 1 to 5 hours in a temperature environment of 1100 to 1400 ° C. and 5 to 50% of hydrogen gas is supplied (S150).

The active agent is oxidized / reduced through the heat treatment process. When the mixture is heated below the above-mentioned temperature environment, the silicate-based crystals are not completely produced and the luminous efficiency is reduced. Problems may arise.

Example

1.35 g of BaO, 0.6 g of SrCO ₃ , 0.11 g of MgO, 0.23 g of SiO ₂ , and 0.17 g of Eu ₂ O ₃ were placed in 50 ml of acetone and mixed for 1 hour. The mixed material was dried in a 200 ° C. dryer for 5 hours. The dried mixed material was placed in a crucible and heat treated at 1200 ° C. for 3 hours. At this time, the heat treatment is heat treatment in an oxidizing atmosphere. After heat treatment in the oxidizing atmosphere, a mixture of 15 vol% hydrogen and 85 vol% nitrogen was injected at 1000 cc / min for 5 hours at 1400 ° C., followed by heat treatment to Ba _3.5 Mg _1.5 Sr _2.1 Si ₂ O ₈ : Eu ²⁺ _0.05 The phosphor to be expressed was prepared.

FIG. 3 is a view illustrating a synthesized form of a phosphor according to an embodiment of the present invention in comparison with a conventional phosphor, and FIG. 4 is a diagram illustrating an emission spectrum of the phosphor according to an embodiment of the present invention in comparison with a conventional phosphor.

Referring to FIG. 3 (b), the phosphor according to the present invention has an average particle size (D ₅₀ ) of 20 μm or less, and less residues are formed and the particle size is smaller than that of the conventional (a) drawing. It can be seen that the morphology (Morphology) is improved, such as small and formed regularly.

4, the "A" graph shows the luminescence brightness of the phosphor according to the present invention, and the "B" graph shows the luminescence brightness of the conventional phosphor, and the luminescence brightness of the phosphor according to the present invention is It was measured to increase by at least 5%.

Hereinafter, a semiconductor light emitting device using the phosphor will be described.

5 is a side cross-sectional view showing the structure of a light emitting device 100 according to a first embodiment of the present invention, Figure 6 is a phosphor (162, 164) of the light emitting device 100 according to the first embodiment of the present invention It is a figure which shows the emission spectrum according to mixing ratio.

The light emitting device 100 according to the first embodiment of the present invention is a surface-mounted white semiconductor light emitting device, and according to FIG. 5, the light source 130 generating light when the anode and cathode lead frames 110 and voltage are applied thereto ), A housing part 120 supporting the lead frame 110 and the light source 130, a wire 140 for energizing the lead frame 110 and the light source 130, and a light transmitting member molded around the light source. And the phosphors 162 and 164 incorporated into the light transmitting member 160, wherein the phosphors 162 and 164 are red phosphors 164 and green phosphors according to an embodiment of the present invention. 162 is provided.

The light source 130 is a light emitting diode chip made of a compound semiconductor, and is provided as a light emitting diode chip that generates light (blue light) having a center wavelength in a region of 430 to 480 nm.

Instead of the light emitting diode chip, a laser diode, a surface emitting laser diode, an inorganic electroluminescence device, an organic electroluminescence device, or the like may be used as the light emitting device having the light emitting main peak in the same wavelength region. In an embodiment of the present invention, a light emitting diode chip which is gallium nitride-based is used.

In addition, the light transmitting member 160 used as a molding member may be an epoxy resin, a silicone resin, a polyimide resin, a urea resin, an acrylic resin, and the like, and in the embodiment of the present invention, a light transmitting epoxy resin or a light transmitting silicone Resins and the like are used.

The light transmitting member 160 may be molded around the light emitting diode chip 130 as a whole, but may be partially molded on the light emitting part as necessary. In other words, in the case of a small-capacity light emitting device, it is preferable to mold it as a whole, but in the case of a high-power light emitting device, molding of the light emitting diode chip 130 by increasing the size of the light emitting diode chip 130 may be performed. Partial molding may be advantageous as it may be disadvantageous for even dispersion.

As described above, the green phosphor 162 incorporated in the light transmitting member 160 may include Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (0 <x ≦ 1, 1 <y <5, It is a phosphor having a chemical composition ratio of 2 <z <5, and is excited by green light, that is, light emitted from the light emitting diode chip 130, and has a light emission main peak in a 500 to 550 nm area.

In addition, since the green phosphor 162 has a particle size of 20 μm or less, it is possible to prevent a problem such that the phosphor 162 is precipitated while being mixed with the light transmitting member 160 to process the molding process. .

The green phosphor 162 has an x value of Eu ²⁺ _x in the range of 0.01 to 0.1, and is mixed with the red phosphor 164 in a ratio of 1: 9 to 9: 1, and 5 for the light transmitting member 160. It mixes in the ratio of -50 wt%.

The red phosphor 164 is excited by light (blue light) having a center wavelength in the region of 430 to 480 nm emitted from the LED chip 130, and various phosphors having a center wavelength in the region of 580 to 640 nm may be used. have.

For example, a sulfide-based phosphor represented by Ca _0.9 S ₁ : Eu ²⁺ _0.1 may be used.

As an example, the sulfide-based phosphor represented by a _0.9 S ₁ : Eu ²⁺ _{0.1 may} be mixed with 2.96 g of CaS, 0.43 g of Eu ₂ O ₃ , 4 g of S using agate trigger, and the mixed material may be The mixture may be prepared by heat treatment while injecting a gas mixed at 20 vol% of hydrogen and 80 vol% of nitrogen at 300 ° C / min at 900 ° C.

In addition, it is also possible to manufacture a pastel-color light emitting device using only the light emitting diode chip 130 and the green phosphor 162.

Referring to FIG. 6, the emission spectrum according to the phosphor mixing ratio of the light emitting device 100 according to the first embodiment is shown. In the "C" graph, the mixing ratio of the green phosphor 162 and the red phosphor 164 is shown. The case of 9: 1 is shown, and the "D" graph shows a case where the mixing ratio of the green phosphor 162 and the red phosphor 164 is 8: 2.

Comparing the two graphs, it was measured to have a similar effect in realizing white light, but when mixed at a ratio of 9: 1, the overall luminance was slightly increased.

By adjusting the mixing ratio of the green phosphor 162 and the red phosphor 164, color coordinates, correlation color temperature (CCT), and color rendering index (CRI) can be controlled.

For reference, the correlation color temperature (CCT) is a temperature when the temperature of the black body is assumed to be equal to the temperature of the object when the color looks like the color of the black body of a certain temperature when the object is shining with visible light it means. The higher the color temperature, the more dazzling and blueish white it is. That is, even if the same white light, the color temperature is low, the color feels a little warmer, if the color temperature is high it feels cold. Therefore, various colors can be realized by adjusting the color temperature.

In addition, the color rendering index (CRI) is an index indicating how close to the color of the object under artificial illumination when it is irradiated with sunlight and has a numerical value from 0 to 100. Therefore, the more white light source that CRI approaches 100, the more similar the color of objects perceived by the human eye under sunlight.

7 is a side cross-sectional view showing the structure of a light emitting device 200 according to a second embodiment of the present invention.

The light emitting device 200 according to the second embodiment of the present invention is a vertical lamp type white semiconductor light emitting device, and according to FIG. 7, a pair of lead frames 210 and a first light source 220 for generating light , A second light source 222, a wire 240 for energizing the lead frame 210 and the light sources 220 and 222, a light transmitting member 270 molded around the light sources 220 and 222, and the light transmission The phosphor 232 dispersed in the member 270 and an exterior member 280 for closing the external space of the entire device are included.

The light emitting device 200 according to the second embodiment of the present invention is distinguished from the first embodiment in that two light sources 220 and 222 are provided instead of two phosphors.

In the description of the light emitting device 200 according to the second embodiment of the present invention, portions overlapping with the first embodiment will be omitted.

The first light source 220 and the second light source 222 is a light emitting diode chip made of a compound semiconductor, the first light source 220 generates light (blue light) having a central wavelength in the region of 430 ~ 480nm, The second light source 222 generates light (red light) having a center wavelength in the region of 580 to 640 nm.

The light transmitting member 270 may be an epoxy resin or a silicone resin, and the phosphor 232 according to the present invention incorporated into the light transmitting member 270 may include Ba _4-x Mg _y Sr _z Si ₂ O ₈ : It is a phosphor having a chemical composition ratio of Eu ²⁺ _x (0 <x ≦ 1, 1 <y <5, 2 <z <5), and has a light emission main peak in a green region, that is, a 500 to 550 nm region.

In addition, the phosphor 232 has a particle size of 20 μm or less, the x value of Eu ²⁺ _x is in the range of 0.01 to 0.1, and is mixed at a ratio of 5 to 50 wt% with respect to the light transmitting member 270. The dots and the like are the same as in the first embodiment described above.

In addition, as in the first embodiment, the color coordinates and the correlated color temperature by adjusting the mixing ratio of the phosphor 232 with respect to the light transmitting member 270, the luminance and the wavelength of the first light source 220 and the second light source 222. (CCT) and color rendering index (CRI) can of course be controlled.

The process of implementing white light by the light emitting device 200 according to the second embodiment of the present invention is as follows.

The blue light in the 430-480 nm wavelength region generated by the first light source 220 passes through the phosphor 232, and part of the light excites the phosphor 232, and has light having a main peak of 500-550 nm. Generates. The remaining light is transmitted as it is as blue light.

Accordingly, blue light generated from the first light source 220, green light excited from the phosphor 232, and red light generated from the second light source 222 may be mixed to finally implement white light.

8 is a diagram illustrating a color coordinate diagram of the light emitting device 200 according to the second embodiment of the present invention.

The color coordinate diagram shown in FIG. 8 is a case where excitation light having a light emission main peak of 450 nm is used, where the point "G" is the color coordinate point of the light excited by the phosphor 232, and the point "E" is the first light source 220. ) Is a color coordinate point of light generated from the reference point, and the "F" point means a color coordinate point of light generated from the second light source 222.

Here, if the mixing ratio of the phosphor 232 to the light transmitting member 270 and the x value of Eu ²⁺ _x are changed, and the luminance and the wavelength of the first light source 220 or the second light source 222 are changed, The point "G" is moved on a straight line connected with the "E" point or a straight line connected with the "F" point.

Therefore, as the parameters of the phosphor 232, the first light source 220, and the second light source 222 are adjusted, white light is a color coordinate within a triangle connecting the "G" point, the "E" point, and the "F" point. It can be implemented at the point, and the desired white light can be obtained by changing the color coordinate, color temperature and color rendering index.

Although the above description has been made based on the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains may not have been exemplified above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to these modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is a diagram showing an emission spectrum according to a change in x value of Eu ²⁺ _x of a phosphor according to an embodiment of the present invention.

2 is a flowchart illustrating a method of manufacturing a phosphor according to an embodiment of the present invention.

3 is a view showing a form in which phosphors are synthesized according to an embodiment of the present invention compared with a conventional phosphor.

4 is a view showing the emission spectrum of the phosphor according to the embodiment of the present invention compared with the conventional phosphor.

5 is a side cross-sectional view showing the structure of a light emitting device according to a first embodiment of the present invention;

6 is a view showing an emission spectrum according to a phosphor mixing ratio of a light emitting device according to a first embodiment of the present invention;

7 is a side sectional view showing a structure of a light emitting device according to a second embodiment of the present invention;

8 is a diagram illustrating a color coordinate diagram of a light emitting device according to a second embodiment of the present invention.

Claims (12)

Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x (where 0 <x ≦ 1, 1 <y <5, and 2 <z <5). The method of claim 1, X is 0.01 to 0.1. Light source; A housing part supporting the light source; A light transmitting member formed in at least a portion of the area around the light source; And Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x incorporated into the light transmitting member, where 0 <x ≦ 1, 1 <y <5, 2 <z <5) A light emitting device comprising a phosphor to be. The method of claim 3, wherein The light source comprises a light emitting diode having a center wavelength in the wavelength range of 430 ~ 480nm. Light source; A housing part supporting the light source; A light transmitting member formed in at least a portion of the area around the light source; And Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x incorporated into the light transmitting member, where 0 <x ≦ 1, 1 <y <5, 2 <z <5) And a second phosphor that is excited by light emitted from the light source and emits light having a center wavelength in a wavelength range of 580 to 640 nm. The method of claim 5, The light source comprises a light emitting diode having a center wavelength in the wavelength range of 430 ~ 480nm. The method of claim 5, Wherein the second phosphor is a sulfide-based phosphor represented by Ca _0.9 S ₁ : Eu ²⁺ _0.1 . The method of claim 5, The first phosphor is excited by the light emitted from the light source to emit light having a central wavelength in the wavelength range of 500 ~ 550nm. A first light source and a second light source; A housing part supporting the first light source and the second light source; A light transmitting member formed in at least a portion of the area around the first light source and the second light source; And Ba _4-x Mg _y Sr _z Si ₂ O ₈ : Eu ²⁺ _x incorporated into the light transmitting member, where 0 <x ≦ 1, 1 <y <5, 2 <z <5) A light emitting device comprising a phosphor to be. The method of claim 9, The first light source includes a light emitting diode that emits light having a center wavelength in the wavelength range of 430 ~ 480nm. The method of claim 9, The second light source includes a light emitting device for emitting light having a central wavelength in the wavelength range of 580 ~ 640nm. The method of claim 10, The phosphor is excited by the light emitted from the first light source to emit light having a central wavelength in the wavelength range of 500 ~ 550nm.

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