KR20130104201A

KR20130104201A - Led package

Info

Publication number: KR20130104201A
Application number: KR1020120025503A
Authority: KR
Inventors: 정정화; 나정현; 김다혜
Original assignee: 서울반도체 주식회사
Priority date: 2012-03-13
Filing date: 2012-03-13
Publication date: 2013-09-25

Abstract

PURPOSE: A light emitting device package is provided to improve the luminous efficiency and lifetime properties of the light emitting device package by suppressing the degradation of a green phosphor due to heat by a ceramic plate which is used for forming the green phosphor. CONSTITUTION: A light emitting device (100) emits light of a preset wavelength by a current which is applied from the outside. A ceramic plate (200) of a green phosphor is formed on the light emitting device. A phosphorous molding unit (300) is formed on the upper surface of the ceramic plate or between the light emitting device and the ceramic plate. The phosphorous molding unit includes one or more non-green phosphors (400). The non-green phosphors are selected among a red phosphor, a blue phosphor, and a yellow phosphor.

Description

Light emitting device package {LED package}

The present invention relates to a light emitting device package, and more particularly to a light emitting device package including a green phosphor ceramic plate.

Light emitting diodes (LEDs) refer to p-n junction diodes in which electrical energy is converted into light energy. When a forward voltage is applied to the pn junction diode, electrons of n-layer and holes of p-layer are combined to emit energy corresponding to the band gap of the conduction band and the valence band. Is emitted in the form of. Such a light emitting device has a low power consumption, a long life, can be installed in a narrow space, and has a strong resistance to vibration. Therefore, it is widely used as a display element and a backlight, and active research is being conducted to apply this to general lighting applications.

Recently, in addition to a single color component, for example, red, blue, or green light emitting devices, light emitting devices that implement white light have been introduced and applied to automobile and lighting products. The white light is largely (1) a method of combining light emission of adjacent red, green and blue light emitting elements, or (2) disposing a phosphor on the light emitting element to convert wavelengths by a part of the primary light emission of the light emitting element and the phosphor. By a method of combining the secondary light emission. Especially, the latter method is mainly applied to the white light emitting element currently commercially available.

On the other hand, the light emitting device generates a lot of heat in accordance with the increase in the amount of current applied, this heat affects the phosphor (phosphor) used to implement the white light to reduce the luminous efficiency. In particular, the fluorescent material around the light emitting device is degraded by a direct effect (degradation), there is a problem in the reliability, such as lowering the luminous efficiency, reduced brightness and shortened product life.

1 is an experimental result confirming the effect of the heat on the specific individual fluorescent material. As can be seen in FIG. 1, the peak of the green phosphor falls at a higher current relative to other phosphors (a), and at a high temperature, the green phosphor is more extinct than other phosphors (b). From the above results, it can be seen that green phosphors are most sensitive to heat among green, red and blue phosphors. In the case of green phosphors, materials such as silicate, sulfite or lightride are generally used. In particular, most of the ultraviolet light emitting device uses a silicate-based green phosphor, in this case, the phenomenon such as the experimental results of Figure 1 may be further intensified.

Therefore, it is necessary to prevent relative premature deterioration of the green phosphor in order to maintain a uniform color temperature for a long time in realizing white light.

An object of the present invention is to provide a light emitting device package in which deterioration of the green phosphor due to heat generated in the light emitting device is suppressed.

In order to achieve the above object, an aspect of the present invention provides a light emitting device, a ceramic plate of a green phosphor formed on the light emitting device, and an upper portion of the ceramic plate or between the light emitting device and the ceramic plate. Provided is a light emitting device package including a fluorescent molding part containing at least one phosphor.

In order to achieve the above object, another aspect of the present invention is formed between a light emitting device, a ceramic plate layer of a green phosphor formed on the light emitting device, an upper portion of the ceramic plate layer, or between the light emitting device and the ceramic plate layer, A light emitting device package including a wavelength conversion layer containing at least one non-green phosphor, and a molding part encapsulating all of the light emitting device, the ceramic plate layer, and the wavelength conversion layer.

The light emitting device may be an ultraviolet light emitting device.

The ceramic plate may be translucent.

The one or more non-green phosphors may be at least one selected from the group consisting of red phosphors, blue phosphors and yellow phosphors.

In the light emitting device package of the present invention, since the green phosphor is made of a ceramic plate having good heat dissipation efficiency, the heat that reaches the green phosphor can be efficiently emitted, thereby suppressing deterioration of the green phosphor due to heat. As a result, there is an effect that the luminous efficiency and lifespan characteristics of the light emitting device package are improved.

However, technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is an experimental result confirming the effect of heat on a specific individual fluorescent material.
2 is a cross-sectional view showing the structure of a light emitting device package according to a first embodiment of the present invention.
3 and 4 are cross-sectional views illustrating a structure in which the fluorescent molding unit and the green ceramic plate are interchanged in the light emitting device package shown in FIG. 2.
5 is a cross-sectional view illustrating a structure of a light emitting device package according to a second exemplary embodiment of the present invention.
6 is a cross-sectional view illustrating a structure in which positions of the wavelength conversion layer and the green ceramic plate are interchanged in the light emitting device package shown in FIG. 5.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood, however, that the present invention is not limited to the embodiments described herein but may be embodied in other forms and includes all equivalents and alternatives falling within the spirit and scope of the present invention.

When a layer is referred to herein as being "on" another layer or substrate, it may be formed directly on another layer or substrate, or a third layer may be interposed therebetween. In the present specification, directional expressions of the upper side, upper side, upper side, and the like can be understood as meaning lower, lower, lower, and the like according to the standard. That is, the expression of the spatial direction should be understood in the relative direction and should not be construed as limiting in the absolute direction.

In the drawings, the thicknesses of the layers and regions may be exaggerated or omitted for the sake of clarity. Like reference numerals designate like elements throughout the specification.

2 is a cross-sectional view showing the structure of a light emitting device package according to a first embodiment of the present invention.

Referring to FIG. 2, the light emitting device package according to the present embodiment includes a light emitting device 100, a ceramic plate 200 of a green phosphor (hereinafter referred to as a “green ceramic plate 200”), and a fluorescent molding part 300. It includes. As shown in FIG. 2, the fluorescent molding part 300 and the green ceramic plate 200 are sequentially formed on the light emitting device 100, and the fluorescent molding part 300 is the light emitting device 100. It is formed to surround. The light 10 or 30 generated by the light emitting device 100 may be wavelength-converted into green light 20 by the green ceramic plate 200 or may be non-green light contained in the fluorescent molding part 300. The phosphor 400 is wavelength-converted into non-green light 40 and emitted to the outside. The green light 40 wavelength-converted and emitted by the green ceramic plate 200 as described above and the non-green light 40 wavelength-converted and emitted by the fluorescent molding part 300 are finally combined. The light 50 of the color is implemented.

The light emitting device 100 emits light of a predetermined wavelength by a current applied from the outside. Here, the light emitting device 100 includes an ultraviolet light emitting device having a peak wavelength of 420 nm or less. However, the present invention is not limited thereto, and the light emitting device 100 may include a light emitting device having a wavelength different from the wavelength. In addition, although FIG. 2 illustrates that a single light emitting device 100 is provided, the present invention is not limited thereto, and a plurality of light emitting devices may be provided.

The fluorescent molding part 300 transmits a portion 10 of the light emitted from the light emitting device 100 to the green ceramic plate 200 or non-radiates the remaining portion 30 of the light generated from the light emitting device 100. -To green light 40. In addition, the fluorescent molding part 300 surrounds the light emitting device 100 to protect the light emitting device 100 from the outside.

In order to transmit some of the light 10 generated by the light emitting device 100 to guide the green ceramic plate 200, the fluorescent molding part 300 is made of a transparent resin. The transparent resin may be any one or a combination of two or more selected from a silicone resin, an epoxy resin, an acrylic resin, or a urethane resin, but is not limited thereto. In particular, since the fluorescent molding part 300 is in direct contact with the light emitting device 100 that emits high temperature heat, the transparent resin is preferably a material that does not have a yellowing phenomenon for a long time even at a high temperature. In order to ensure heat resistance and light resistance, the transparent resin is preferably a silicone resin.

In order to convert the remaining light 30 generated in the light emitting device 100 into the non-green light 40, the fluorescent molding part 300 includes at least one non-green phosphor 400. do. The non-green phosphor 400 may be a known phosphor such as YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride, or phosphate. Can be. The non-green phosphor 400 may be any one or two or more selected from the group consisting of a red phosphor, a blue phosphor, and a yellow phosphor. The red phosphor is Y ₂ O ₂ S: Eu, Y ₂ O ₃ : Eu, YVO ₄ : Eu, Y (V, P) O ₄ : Eu, (Y, Gd) BO ₂ : Eu, SrTiO ₃ : Pr , CaAlSi (ON) ₃ : Eu, etc. may be used, and as the blue phosphor, SrGa ₂ S ₄ : Ce, ZnS: Ag, Y ₂ SiO ₅ : Ce, Sr ₅ (PO ₄ ) ₃ Cl: Eu, ZnS : Ag, BaMgAl ₁₀ O ₁₇ : Eu or the like can be used. The yellow phosphor may be a YAG or TAG garnet-based phosphor, or an A ₂ SiO ₄ having a 2,1,4 composition, or an A ₃ SiO ₅ silicate having a 3,1,5 composition, or an nitride having an alpha-SiAlON composition. It may include any one of the system. Where A may be Sr, Ba, Ca, Mg, Sr is an essential component and Ba, Ca, Mg may be optionally included (0≤Ba, Ca, Mg≤1) as needed. In particular, when the light 50 of the finally implemented color is white light, the fluorescent molding part 300 includes a red phosphor and a blue phosphor. The red phosphor may be CaAlSi (ON) ₃ : Eu, and the blue phosphor may be BaMgAl ₁₀ O ₁₇ : Eu.

The green ceramic plate 200 guides the light 40 wavelength-converted into the non-green color by the fluorescent molding part 300 to the outside, and at the same time, a part 10 of the light generated by the light emitting device 100. Is converted into green light 20 and emitted to the outside.

The green ceramic plate 200 is composed of a polycrystalline sintered body of a translucent ceramic material obtained by heating and sintering a green phosphor together with additives such as binder resin, dispersant, and sintering aid at high pressure. The green phosphor used to manufacture the green ceramic plate 200 may include any one of silicate, sulfide and nitride. The silicate-based green phosphor may include A ₂ SiO ₄ having a 2,1,4 composition or A ₃ SiO ₅ silicate having a 3,1,5 composition, or a sulfide or Beta-SiAlON composition having a SrGa ₂ S ₄ : Eu composition. It may include any one of the nitride system. Where A may be Sr, Ba, Ca, Mg, Sr is an essential component and Ba, Ca, Mg may be optionally included (0≤Ba, Ca, Mg≤1) as needed. In particular, the green phosphor may be (BaSr) ₂ SiO ₄ : Eu.

In order to transmit light of the polycrystalline sintered compact, the density of the polycrystalline sintered compact constituting the green ceramic plate 200 may be 99.0% or more, more preferably 99.90% or more. By increasing the density of the sintered compact as described above, light scattering sources included in the green ceramic plate 200 can be relatively reduced, and as a result, light transmittance can be improved. If the thickness of the green ceramic plate 200 is less than 50 μm, the green ceramic plate 200 may be damaged or cracked, making manufacturing and handling difficult. If the thickness is more than 1000 μm, the processing after manufacturing becomes difficult. Therefore, the thickness of the green ceramic plate 200 is preferably 50 ㎛ to 1000 ㎛.

Unlike the non-green phosphor 400 which is dispersed and included in the resin constituting the fluorescent molding part 300, the green phosphor forms the green ceramic plate 200 in the form of a polycrystalline sintered body of high density. That is, since the material having thermal conductivity such as resin is excluded from the green ceramic plate 200, heat generated from the green phosphor is efficiently discharged through the green ceramic plate 200, thereby improving heat dissipation.

The non-green light 40 emitted to the outside by transmitting the green ceramic plate 200 and the green light 20 wavelength-converted and emitted by the green ceramic plate 200 are combined to have a desired color. Light 50 is implemented. In particular, in order to implement white light, the light emitting device package of the present invention is the light emitting device 10 is an ultraviolet light emitting device, the non-green phosphor 400 included in the fluorescent molding unit 300 is a red phosphor and blue It may be composed of a phosphor. In the configuration as described above, the light (ultraviolet rays) emitted from the light emitting device 100 is wavelength-converted into red light and blue light by the red and blue phosphors contained in the fluorescent molding part 300 and is emitted to the outside, and the green ceramic The wavelength is converted into green light by the green phosphor constituting the plate 200 and emitted to the outside. As described above, the light 50 finally emitted by the combination of red light, blue light and green light emitted to the outside becomes white light.

In the light emitting device package according to the present exemplary embodiment, in order to convert wavelengths of the light 10 and 30 emitted from the light emitting device 100, phosphors are formed in a multilayer structure. In addition, the green phosphor having low heat resistance in the multilayer structure is formed of a green ceramic plate 200 composed of a polycrystalline sintered body. That is, since the green phosphor is formed of a ceramic material having good heat dissipation efficiency, deterioration of the green phosphor due to heat generated from the light emitting device 100 can be minimized, and the light emission efficiency of the package can be improved.

Meanwhile, the embodiment of the present invention is not limited thereto, and the positions of the green ceramic plate 200 and the fluorescent molding part 300 may reflect light emitted from the light emitting device 100 through a reflective structure (not shown). It may be formed in the region. That is, the light emitting device 100 may be formed at a lower side or a separate position instead of the upper direction. In addition, it may be located in combination with a separate member (not shown).

3 and 4 are cross-sectional views illustrating structures in which the fluorescent molding unit 300 and the green ceramic plate 200 are interchanged in the light emitting device package of FIG. 2.

Referring to FIG. 3, the fluorescent molding part 300 is disposed on the green ceramic plate 200, and has a same component as described in FIG. 2, and a chip molding part under the green ceramic plate 200. 500 is located. That is, the chip molding part 500, the green ceramic plate 200, and the fluorescent molding part 300 are sequentially formed in the light emitting device 100, and the chip molding part 500 is the light emitting device 100. It is formed to surround.

The chip molding part 500 separates the green ceramic plate 200 from the light emitting device 100 and protects the light emitting device 100.

The chip molding part 500 is preferably made of a transparent resin. The transparent resin may be any one or a combination of two or more selected from a silicone resin, an epoxy resin, an acrylic resin, or a urethane resin, but is not limited thereto.

In addition, the chip molding part 500 is preferably configured to have a refractive index between the refractive index of the light emitting device 100 and the refractive index of the outside air for effective light extraction. In particular, when the chip molding part 500 is formed between the light emitting device 100 and the green ceramic plate 200, as shown in FIG. 3, the chip molding part 500 is the light emitting device. It is preferable that the material has a refractive index smaller than that of 100 and larger than the green plate 200.

The green ceramic plate 200 may be disposed relatively closer to the light emitting device 100 than the fluorescent molding part 300 containing the non-green phosphor. Since the green ceramic plate 200 is excellent in heat dissipation efficiency, the green ceramic plate 200 is not easily deteriorated by heat generated from the light emitting device 100.

Referring to FIG. 4, the green ceramic plate 200 may be formed in contact with the light emitting device 100. In this case, the chip molding part 500 is formed so as to surround only the side portion of the light emitting device 100.

Even in the case of the direct contact as described above, the green ceramic plate 200 is not easily degraded by the excellent heat dissipation characteristics.

5 is a cross-sectional view illustrating a structure of a light emitting device package according to a second exemplary embodiment of the present invention.

Referring to FIG. 5, the light emitting device package according to the present embodiment may include a ceramic plate 250 (hereinafter, referred to as a 'green ceramic plate 250') and a wavelength conversion layer 350 of a green phosphor. After the chip is formed in the chip size, it is similar to that described with reference to FIG. 2 except that the molding part 550 is formed.

The light emitting device 100 is the same as the light emitting device 100 described in the first embodiment, and the above description is used.

The wavelength conversion layer 350 is the same in terms of configuration and function as the 'fluorescent molding part 300' described in the first embodiment, and is not formed to enclose and encapsulate the light emitting device 100. The only difference is that they are formed by being stacked on the device 100. Therefore, for the configuration and function of the wavelength conversion layer 350, the description of the 'fluorescent molding part 300' of the 'Example 1' is used.

The green ceramic plate 250 is also the same in terms of configuration and function as the 'green ceramic plate 200' described in the first embodiment, the 'green ceramic plate 200' of the 'Example 1' Use the description.

The molding part 550 is formed to surround and encapsulate all of the light emitting device 100, the wavelength conversion layer 350, and the green ceramic plate 250 on the upper portion of the green ceramic plate 250. It protects them from the outside.

The molding part 550 is preferably made of a transparent resin. The transparent resin may be any one or a combination of two or more selected from a silicone resin, an epoxy resin, an acrylic resin, or a urethane resin, but is not limited thereto.

6 is a cross-sectional view illustrating a structure in which positions of the wavelength conversion layer 350 and the green ceramic plate 250 are interchanged in the light emitting device package of FIG. 5.

Referring to FIG. 6, the same components as described in FIG. 5 are formed, and the wavelength conversion layer 350 and the green ceramic plate 250 are formed to be interchanged with each other.

The green ceramic plate 250 may be formed in contact with the light emitting device 100. Even when the green ceramic plate 250 and the light emitting device 100 are in direct contact, deterioration of the green phosphor does not occur due to the excellent heat dissipation characteristics of the green ceramic plate 250.

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, This is possible.

Claims

A light emitting element;
A ceramic plate of green phosphor formed on the light emitting element; And
And a fluorescent molding portion formed on the ceramic plate or between the light emitting element and the ceramic plate and containing at least one non-green phosphor.

The method of claim 1,
The light emitting device is a light emitting device package, characterized in that the ultraviolet light emitting device.

The method of claim 1,
The ceramic plate is a light emitting device package, characterized in that the light transmitting.

The method of claim 1,
The at least one non-green phosphor is at least one light emitting device package, characterized in that at least one selected from the group consisting of a red phosphor, a blue phosphor and a yellow phosphor.

The method of claim 1,
A fluorescent molding portion containing at least one non-green phosphor is formed on the ceramic plate,
The light emitting device package, characterized in that the chip molding is formed between the light emitting device and the ceramic plate.

A light emitting element;
A ceramic plate of green phosphor formed on the light emitting element;
A wavelength conversion layer formed on the ceramic plate or between the light emitting element and the ceramic plate and containing one or more non-green phosphors; And
A light emitting device package including a molding unit encapsulating all of the light emitting device, the ceramic plate and the wavelength conversion layer.

The method according to claim 6,
The light emitting device is a light emitting device package, characterized in that the ultraviolet light emitting device.

The method according to claim 6,
The ceramic plate is a light emitting device package, characterized in that the light transmitting.

The method according to claim 6,
The at least one non-green phosphor is at least one light emitting device package, characterized in that at least one selected from the group consisting of a red phosphor, a blue phosphor and a yellow phosphor.