KR20120038776A - Light emitting device - Google Patents

Light emitting device Download PDF

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KR20120038776A
KR20120038776A KR1020100100416A KR20100100416A KR20120038776A KR 20120038776 A KR20120038776 A KR 20120038776A KR 1020100100416 A KR1020100100416 A KR 1020100100416A KR 20100100416 A KR20100100416 A KR 20100100416A KR 20120038776 A KR20120038776 A KR 20120038776A
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light
light emitting
semiconductor layer
conductive semiconductor
layer
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KR1020100100416A
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Korean (ko)
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박덕현
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엘지이노텍 주식회사
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/10—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a light reflecting structure, e.g. semiconductor Bragg reflector
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/16—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
    • H01L33/22—Roughened surfaces, e.g. at the interface between epitaxial layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H01L33/40—Materials therefor
    • H01L33/42—Transparent materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
    • H01L2933/0008—Processes
    • H01L2933/0033—Processes relating to semiconductor body packages
    • H01L2933/0041—Processes relating to semiconductor body packages relating to wavelength conversion elements

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Led Devices (AREA)

Abstract

PURPOSE: A light emitting device is provided to consecutively change a refractive index in a direction toward the outside of an active layer, thereby improving light extraction efficiency. CONSTITUTION: A light emitting structure comprises an active layer(150) between a first conductivity type semiconductor layer and a second conductivity type semiconductor layer(140). A light extraction structure includes an uneven structure on a single region of the first conductivity type semiconductor layer. The light extraction structure includes a photonic crystal structure and has refractive index smaller than the refractive index of the first conductivity type semiconductor layer. The photonic crystal structure is formed on the uneven structure of the light extraction structure.

Description

Light Emitting Device

An embodiment relates to a light emitting device.

Group III-V nitride semiconductors are spotlighted as core materials of light emitting devices such as light emitting diodes (LEDs) or laser diodes (LDs) due to their physical and chemical properties. The nitride light emitting device generates light using an energy band gap of an active layer positioned between an n-type GaN semiconductor layer and a p-type GaN semiconductor layer.

Such nitride semiconductors are absorbed by the light generated in the active layer or are lost while causing total reflection, so as to increase the amount of light in the active layer, various technologies for extracting light generated in the active layer to the outside are required.

The embodiment provides a light emitting device that improves light extraction efficiency by sequentially changing the refractive index in the direction from the active layer to the outside.

The light emitting device according to the embodiment includes a light emitting structure having an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer, and one region of the first conductive semiconductor layer includes a light extraction structure having an uneven structure. The light extraction structure may include a photonic crystal structure, and the refractive index of the photonic crystal structure may be smaller than that of the first conductive semiconductor layer.

The light emitting device according to the embodiment includes a light emitting structure on the substrate, the light emitting structure having an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer, a light transmissive electrode layer on the light emitting structure, and a first conductive semiconductor layer; The light extraction control layer may be disposed between the light transmissive electrode layers and have a refractive index smaller than that of the first conductive semiconductor layer.

The embodiment allows the light generated in the active layer to be properly extracted to the outside by the difference in refractive index.

1 schematically shows a cross section of a light emitting element according to the first embodiment.
2 is a reference view for explaining the relationship between the refractive index and the critical angle of the medium.
3 shows a cross-sectional view of a light emitting device according to the second embodiment.
4 and 5 show reference views for an arrangement interval of a photonic crystal structure and an example of the crystal structure according to the second embodiment.
6 shows an example of the form when Gd 2 O 3 is deposited on the photonic crystal structure according to the second embodiment.
7 to 15 illustrate reference diagrams for describing a process of a light emitting device according to a second embodiment.
FIG. 16 shows a reference diagram for the spacing and light extraction efficiency of the photonic crystal structure when the photonic crystal structure is applied.
17 is a cross-sectional view showing a cross section of a light emitting device package according to the embodiment.
18A is a perspective view illustrating a lighting apparatus according to an embodiment, and FIG. 18B is a cross-sectional view illustrating a cross-sectional view taken along line AA ′ of the lighting apparatus of FIG. 18A.
19 is an exploded perspective view of a liquid crystal display according to an embodiment.
20 is an exploded perspective view of a liquid crystal display according to an embodiment.

In the description of embodiments, each layer, region, pattern, or structure is “under” a substrate, each layer (film), region, pad, or “on” of a pattern or other structure. In the case of being described as being formed on the upper or lower, the "on", "under", upper, and lower are "direct" "directly" or "indirectly" through other layers or structures.

In addition, the description of the positional relationship between each layer or structure, please refer to this specification, or drawings attached to this specification.

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 and area of each component does not necessarily reflect the actual size or area.

Hereinafter, a light emitting device according to an embodiment will be described with reference to the accompanying drawings.

1 schematically shows a cross section of a light emitting element according to the first embodiment.

Referring to FIG. 1, a light emitting device according to the first embodiment may include a support substrate 110, a reflective layer 120, a passivation 130, a second conductive semiconductor layer 140, an active layer 150, and a first conductive semiconductor layer. 160, a light extraction control layer 170, a light transmissive electrode layer 180, and an electrode 190. The support substrate 110 may be formed using a material having excellent thermal conductivity and may be formed of a conductive material, and may be formed using a metal material or a conductive ceramic. The support substrate 110 may be formed in a single layer, or may be formed in a double structure or multiple structures.

That is, the support substrate 110 may be formed of any one selected from, for example, Au, Ni, W, Mo, Cu, Al, Ta, Ag, Pt, and Cr, or may be formed of two or more alloys. Can be formed by laminating.

The support substrate 110 may facilitate the emission of heat generated from the light emitting device 100 to improve the thermal stability of the light emitting device 100.

Passivation 130 for supporting the reflective layer 120 is formed on both side ends on the support substrate 110, and the reflective layer 120 is formed in the center where the passivation 130 is not formed. The reflective layer 120 is provided to reflect the light generated from the active layer 150 in the direction of the electrode 190, and Ag, Al, and one of these oxides may be deposited between the passivation 130.

The light emitting structure for generating light is formed on the reflective layer 120. The light emitting structure includes the second conductive semiconductor layer 140, the active layer 150, and the first conductive semiconductor layer 160, and may be sequentially disposed in the direction of the electrode 190 in the reflective layer 120.

The first conductive semiconductor layer 160 may include an n-type semiconductor layer, the n-type semiconductor layer is InxAlyGa1-x-yN (0≤x≤1, 0≤y≤1, 0≤x + y≤1) A semiconductor material having a compositional formula of, for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN and the like can be selected, and n-type dopants such as Si, Ge, C, and Sn can be doped. .

The active layer 150 may be a semiconductor layer in which a light emitting material made of indium gallium nitride (InGaN) is added as a light emitting region. Process conditions for the growth of the active layer 150, for example, using a nitrogen gas as a carrier (carrier) gas at a growth temperature of 780 ℃ supplying NH3, TMGa, and trimethyl indium (TMIn), the active layer 150 made of InGaN ) Can be grown to a thickness of 120 kV to 1200 kV. In this case, the active layer 150 may have a stacked structure in which the molar ratio of each elemental component of InGaN is grown at different rates.

In addition, the active layer 150 may be formed of one of a single quantum well structure, a multi quantum well structure (MQW), a quantum wire structure, and a quantum dot structure. However, the present embodiment will be described based on the multi quantum well structure, but the present invention is not limited thereto.

The active layer 150 is in this case formed of a quantum well structure, for example, having a compositional formula of In x Al y Ga 1 -x- y N (0≤x≤1, 0≤y≤1, 0≤x + y≤1) It may have a single or quantum well structure having a well layer and a barrier layer having a compositional formula of In a Al b Ga 1 -a- b N (0≤a≤1, 0≤b≤1, 0≤a + b≤1). Can be. The well layer may be formed of a material having a lower band gap than the band gap of the barrier layer.

The second conductive semiconductor layer 140 may be formed of a P-type GaN layer, and may supply holes to the active layer 150 by a driving current applied from the outside to allow holes and electrons to couple in the active layer 150. . The second conductive semiconductor layer 140 may be implemented as a p-type semiconductor layer doped with a p-type dopant. The p-type semiconductor layer is a semiconductor material having a composition formula of In x Al y Ga 1 -x- y N (0≤x≤1, 0≤y≤1, 0≤x + y≤1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN and the like may be selected, and p-type dopants such as Mg, Zn, Ca, Sr, and Ba may be doped.

Meanwhile, a semiconductor layer having a polarity opposite to that of the second semiconductor layer may be formed under the second conductive semiconductor layer 140. That is, when the second conductivity type semiconductor layer 140 is a P type semiconductor layer, an N type semiconductor layer may be further formed. In addition, the first conductive semiconductor layer 160 may be a P-type semiconductor layer, and the second conductive semiconductor layer 140 may be implemented as an N-type semiconductor layer. Accordingly, the light emitting device according to the first embodiment may include at least one of an N-P junction, a P-N junction, an N-P-N junction, and a P-N-P junction structure.

The light extraction control layer 170 is positioned between the first conductive semiconductor layer 160 and the transparent electrode layer 180, and the light extraction control layer 170 is lower than the refractive index of the first conductive semiconductor layer 160 and is a molding material. It may have a refractive index larger than the refractive index of. The molding material may be made of epoxy or the like, but is not limited thereto.

For example, the light extraction control layer 170 may have a refractive index between the refractive index (eg, 2.3) of the first conductive semiconductor layer 160 and the refractive index (eg, 1.5) of the molding epoxy. By making the refractive index of the light extraction control layer 170 have a value between the refractive index of the molding epoxy and the refractive index of the first conductive semiconductor layer 160, the critical angle of the light from the first conductive semiconductor layer 160 to the outside can be increased. have. Typically, the critical angle is defined by Equation 1 below, and the smaller the difference in refractive index between the first conductive semiconductor layer 160 and the light extraction control layer 170 tends to increase.

Figure pat00001

Here, the refractive index is n2 is larger than n1.

The critical angle (Sin ic ) can be found as the ratio of the refractive index between the two media. Here, n1 represents the refractive index of the medium in the direction in which light is emitted, and n2 represents the refractive index of the medium on the side of receiving light. Thus, the critical angle has a larger value as the difference in refractive index between the two media is smaller.

This will be described with reference to FIG. 2 together.

Referring to FIG. 2, the refractive index n air of air is 1, the refractive index n epoxy of the molding epoxy is 1.5, and the refractive index of the refractive index n GaN of the first conductive semiconductor layer 160 is 2.3. Assuming that the refractive index n 2.0 of the light extraction control layer 170 according to the embodiment is 2.0,

1) the critical angle of n air / n GaN is 26 degrees,

2) the critical angle of n epoxy / n GaN is 40.7 degrees,

3) The critical angle of n air / n epoxy is 41,8 degrees,

4) n 2 .0 / n critical angle of GaN is 60.4 degrees,

5) n epoxy / n 2 . A critical angle of zero represents 48.6 degrees.

As shown in FIG. 2, when the light extraction control layer 170 is smaller than the refractive index of the first conductive semiconductor layer 160 and is larger than the refractive index of the molding epoxy, the critical angle may reach a maximum of 60.4 degrees. .

In Equation 1, when the angle of light from n1 to n2 is smaller than the critical angle, total internal reflection does not occur, so the light extraction efficiency increases as the critical angle is larger.

Since the light extraction control layer 170 must transmit the light while increasing the critical angle of the light incident from the first conductive semiconductor layer 160, the light extraction control layer 170 needs to be made of a transparent or translucent material. The light extraction control layer 170 may be deposited on the first conductive semiconductor layer 160, and may include SiO, Al 2 O 3 , TiO 2 , TiO, Ti 2 O 3 , HfO 2 , and Ta 2. O 5 , ZrO 2 , Y 2 O 3 , CeO 2 , Gd 2 O 3 , Sm 2 O 3 , MgO, ZnO, NiO, CeF 3 , BaTiO 3 , PrTiO 3 , Zn1-xMgxO, Zn1-yBeO, Zn1-x -yMgxBeyO, Zn1-zCdzO, ITO, SiNx, MgAl 2 O 4, AlON, CeF 3, PbF 2, LaF 3 from one or may be two or more is selected, 1Å? It is preferably formed to a thickness of 300 μm.

On the other hand, the light extraction control layer 170 made of the above material is deposited on the first conductive semiconductor layer 160 by a deposition process, or processed in the form of a wafer to the first conductive semiconductor layer 160. You can also bond. When the light extraction control layer 170 is directly bonded to the first conductive semiconductor layer 160, the light extraction control layer 170 may have a first conductivity through ITO, Ni, AZO, Ti, Pd, and Pt. The semiconductor layer 160 may be in ohmic contact.

The light transmissive conductive layer 180 may be formed on the light extraction control layer 170 to emit light generated by the light emitting structure to the outside.

The transparent electrode layer 180 is formed of ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx, RuOx. / ITO, Ni / IrOx / Au and Ni / IrOx / Au / ITO, and may be formed to reduce contact resistance between the second conductive semiconductor layer 140 and the electrode 190 and to spread current. Can play a role.

In addition, the transparent electrode layer 180 is preferably a transparent or semi-transparent material so that the light emitted from the active layer 150 can be easily directed to the outside, the light generated in the active layer 150 is well emitted to the upper region A light extracting structure may be formed that allows for the light to be extracted. The light extraction structure may give a roughness to the upper surface of the transparent electrode layer 180, give a concave-convex structure, or give a prism structure so that light generated in the active layer 150 may be efficiently emitted.

3 shows a cross-sectional view of a light emitting device according to the second embodiment.

3 illustrates an example in which the photonic crystal structures 170a to 170n are formed in the first conductive semiconductor layer 160 to increase the critical angle of light directed toward the outside from the first conductive semiconductor layer 160. Accordingly, the embodiment of FIG. 3 may include the support substrate 110, the reflective layer 120, the passivation 130, the second conductive semiconductor layer 140, the active layer 150, and the electrode 190 of FIG. 1. Since the structure is the same, the same reference numeral is given, and redundant descriptions are omitted.

Referring to FIG. 3, the light emitting device according to the second embodiment forms a light extracting structure in the first conductive semiconductor layer 160, and the formed light extracting structure has a photonic crystal structure 170a to 170n. To increase the extraction efficiency of the light from the active layer 150 toward the electrode 190 and to scatter the extracted light. The refractive indexes of the photonic crystal structures 170a to 170n are molded with the first conductive semiconductor layer 160. It can have a value between the refractive index of the material. The molding material may be made of epoxy or the like, but is not limited thereto.

For example, assuming that the refractive index of the first conductive semiconductor layer 160 is 2.3 and the refractive index of the molding epoxy resin is 1.5, the refractive index of the photonic crystal structures 170a to 170n is 1.5 ?. It may have a range of 2.3.

Here, the molding epoxy resin is an encapsulant that seals the light emitting device when the light emitting device is packaged according to the embodiment to form a light emitting device package. The molding epoxy resin may include a phosphor according to a wavelength of light emitted from the light emitting device. . The molding epoxy resin is positioned just before the light generated in the active layer 150 goes out into the atmosphere, and should have a value higher than the refractive index of the atmosphere in consideration of the direction of light from the active layer 150 toward the atmosphere.

The photonic crystal structures 170a to 170n may be deposited and formed on the concave-convex shape of the light extracting structure formed on the first conductive semiconductor layer 160. Therefore, when the light extracting structure formed on the first conductive semiconductor layer 160 has a predetermined pattern, the photonic crystal structures 170a to 170n may be arranged at regular intervals when viewed from the direction of the electrode 190. If the pattern is 400 nm? If formed at 600 nm intervals, the photonic crystal structures 170a to 170n are also 400 nm to It can be arranged at 600 nm intervals. That is, the arrangement interval of the photonic crystal structures 170a to 170n may be determined by the pattern interval of the light extracting structure formed on the first conductive semiconductor layer 160.

When the photonic crystal structures 170a to 170n are emitted from the active layer 150 through the first conductive semiconductor layer 160 to the atmosphere, the light crystal structure 170a to 170n reduces the difference in refractive index of the medium through which the light passes to increase the light extraction efficiency. Therefore, the photonic crystal structure 170a-170n should be a transparent or semitransparent material through which light can pass, and SiO, Al 2 O 3 , TiO 2 , TiO, Ti 2 O 3 , HfO 2 , Ta 2 O 5 , ZrO 2 , Y 2 O 3 , CeO 2 , Gd 2 O 3 , Sm 2 O 3 , MgO, ZnO, NiO, CeF 3 , BaTiO 3 , PrTiO 3 , Zn1-xMgxO, Zn1-yBeO, Zn1-x-yMgxBeyO, Zn1 -zCdzO, ITO, SiNx, MgAl 2 O 4 , AlON, CeF 3 , PbF 2 , LaF 3 At least one of the materials may be used.

After the photonic crystal structure 170a ˜ 170n is formed on the first conductive semiconductor layer 160, the light transmissive electrode layer 180 and the electrode 190 may be sequentially formed. The transmissive electrode layer 180 provides a driving current applied from the electrode 190 to the first conductive semiconductor layer 160 and is formed on the photonic crystal structure 170a to 170n to allow light to transmit to the outside. Therefore, the transparent electrode layer 180 should be electrically conductive and transparent or translucent material, and should include ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO). , IGZO (In-Ga ZnO), IrOx, RuOx, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO.

4 and 5 show reference views for an arrangement interval of a photonic crystal structure and an example of the crystal structure according to the second embodiment.

First, referring to FIG. 4, the upper side views of FIGS. 4A, 4B, and 4C show what is viewed from the direction of the electrode 190, and the lower side shows what is seen from the upper oblique direction. FIG. 4A shows the form when the photonic crystal structure has a spacing of 500 nm, FIG. 4B shows 550 nm, and FIG. 4C shows 600 nm. The gap of the photonic crystal structure shown in FIG. 4 may be determined according to the interval of the light extraction structure formed in the first conductive semiconductor layer 160.

FIG. 5 shows an example of the shape of the photonic crystal structure when Y 2 O 3 is deposited on the photonic crystal structure according to the second embodiment.

FIG. 5A illustrates an example of a surface photograph of the first conductive semiconductor layer 160 when the photonic crystal structure is not formed in the first conductive semiconductor layer 160.

FIG. 5B shows the shape when the photonic crystal structure is formed at an interval of 500 nm, and it can be seen that the photoconductive structure is arranged in the first conductive semiconductor layer 160 at regular intervals. Since the photonic crystal structure 170a to 170n has a radial crystal structure, the incident light may be scattered, and the scattered light may pass through the transmissive electrode layer 180 to the epoxy molding resin.

FIG. 5C illustrates an example in which the photonic crystal structures are formed at 550 nm intervals, and FIG. 5D illustrates an example in which the photonic crystal structures are formed at 600 nm intervals. As the distance between the photonic crystal structures 170a to 170n increases, the area and volume of each of the photonic crystal structures 170a to 170n may increase, and as shown in FIG. 5 (d), the photonic crystal structures 170a to 170n may be separated from each other. When grown to be adjacent to each other, since a light extraction structure having a refractive index between the epoxy molding resin and the first conductive semiconductor layer 160 is disposed on most of the surface of the first conductive semiconductor layer 160, the light extraction efficiency is increased, as well as radial. Increasing the volume of the crystal structure can improve the light scattering properties.

6 shows an example of the form when Gd 2 O 3 is deposited on the photonic crystal structure according to the second embodiment.

6 (a), 6 (b) and 6 (c) show photographs when the intervals between the photonic crystal structures are 500 nm, 550 nm and 600 nm, respectively, and Y 2 O 3 described with reference to FIG. 5. Compared with the photonic crystal structure deposited with the material, the shape is similar, but the size is larger.

7 to 15 illustrate reference diagrams for describing a process of a light emitting device according to a second embodiment.

7 to 15, the second conductive semiconductor layer 140, the active layer 150, and the first conductive semiconductor layer 160 are sequentially formed on the sapphire substrate 50.

Next, in FIG. 8, passivation 130 is formed on the left and right sides of the region in which the reflective layer 120 is to be disposed, and as shown in FIG. 9, one of Ag, Al, and an oxide thereof is interposed between the passivation 130. Deposition is performed to form the reflective layer 120. After the reflective layer 120 is formed, as shown in FIG. 10, one of AuSn, AuIn, PdSn, PdIn, and NiSn is applied to the first conductive semiconductor layer 160 to bond the wafer to replace the sapphire substrate 50. It may be deposited by the bonding layer 111.

After the bonding layer 111 is formed, as shown in FIG. 11, the substrate 110 may be bonded to the bonding layer 111. The substrate 110 may be a metal material such as Cu or Ni, or a wafer made of Si, Ge, CuW, Mo, Ni, or SiC.

After the substrate 110 is deposited on the bonding layer 111, as shown in FIG. 12, the sapphire substrate 50 is separated by a laser lift off (LLO) process, and when the sapphire substrate 50 is separated, FIG. 13. As shown in FIG. 1, a light extracting structure may be formed in the first conductive semiconductor layer 160. The light extracting structure may form a regular concave-convex shape, a prism structure, or an irregular scratch shape on one surface of the first conductive semiconductor layer. However, in this embodiment, the light extraction structure is to illustrate and explain that the tip is a pointed prism shape.

After the light extraction structure is formed, as shown in FIG. 14, the light extraction structure may include the photonic crystal structure 170a. For example, it may be formed on the uneven shape of the light extraction structure. The material of the photonic crystal structure 170a has a refractive index between the refractive index of the first conductive semiconductor layer 160 and the refractive index of the molding epoxy resin. Preferably, the photonic crystal structure 170a is 1.5? It may be a material having a refractive index of 2.3, and 1.5? It has a refractive index of 2.3 and transmits light.SiO, Al 2 O 3 , TiO 2 , TiO, Ti 2 O 3 , HfO 2 , Ta 2 O 5 , ZrO 2 , Y 2 O 3 , CeO 2 , Gd 2 O 3 , Sm 2 O 3 , MgO, ZnO, NiO, CeF 3 , BaTiO 3 , PrTiO 3 , Zn1-xMgxO, Zn1-yBeO, Zn1-x-yMgxBeyO, Zn1-zCdzO, ITO, SiNx, MgAl 2 O 4 , AlON, CeF 3 , PbF 2 , LaF 3 One of can be selected.

Finally, FIG. 15 illustrates an example in which the light-transmissive electrode layer 180 and the electrode 190 are formed thereon after the photonic crystal structure 170a is deposited. In the light emitting device formed by the above process, the light extraction efficiency is increased as compared with the conventional light emitting device, and since light is sufficiently scattered by the photonic crystal structure, light concentration may be reduced and uniform brightness may be obtained. .

FIG. 16 shows a reference diagram for the spacing and light extraction efficiency of the photonic crystal structure when the photonic crystal structure is applied.

Referring to FIG. 16, the graph shown is 300 nm? On the basis that the interval of the photonic crystal structure is 200 nm. The relative value calculated for 700 nm is shown.

In FIG. 16, the calculated efficiency represents a simulation result according to the pitch of the photonic crystal structure according to the embodiment, and the measured efficiency represents the measured result. As shown in FIG. 16, the maximum value is shown when the interval between the photonic crystal structures that gradually varies the refractive index from the first conductive semiconductor layer 160 to the epoxy molding resin is 500 nm. In general, the light extraction efficiency tends to increase as the pitch between the photonic crystal structures 170a-170n increases. However, in the vicinity of 600 nm, the spacing and the light extraction efficiency of the photonic crystal structures 170a-170n are linear. It can be seen that it is not proportionally. The experimental results show that the gap between the photonic crystal structures 170a? 170n is 450 nm? At 550 nm, this indicates the optimum light extraction efficiency.

17 is a cross-sectional view showing a cross section of a light emitting device package according to the embodiment.

Referring to FIG. 17, the light emitting device package 200 according to the embodiment includes a body 210 having a cavity formed therein, a light source unit 220 mounted on a bottom surface of the body 210, and an encapsulant 230 filled in the cavity. The encapsulant 230 may include the phosphor 240.

The body 210 is made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photosensitive glass (PSG), polyamide 9T (PA9T) ), Neo geotactic polystyrene (SPS), a metal material, sapphire (Al2O3), beryllium oxide (BeO), a printed circuit board (PCB, Printed Circuit Board), it may be formed of at least one. The body 210 may be formed by injection molding, etching, or the like, but is not limited thereto.

The inner surface of the body 210 may be formed inclined surface. The angle of reflection of the light emitted from the light source unit 220 may vary according to the angle of the inclined surface, thereby adjusting the directing angle of the light emitted to the outside.

The shape of the cavity formed in the body 210 as viewed from above may be circular, rectangular, polygonal, elliptical, or the like, and in particular, the corner may be curved, but is not limited thereto.

The light source unit 220 may be mounted on the bottom surface of the body 210. For example, the light source unit 220 may be a light emitting device illustrated and described with reference to FIGS. 1 and 3. The light emitting device may be, for example, a colored light emitting device emitting light of red, green, blue, white, or the like, or an ultraviolet (Ultra Violet) light emitting device emitting ultraviolet light, but is not limited thereto. In addition, one or more light emitting devices may be mounted.

Meanwhile, the light emitting device according to the embodiment includes a light extraction structure in one region of the first conductive semiconductor layer, and the light extraction structure has a refractive index lower than that of the first conductive semiconductor layer and larger than that of the encapsulant 230. Including the photonic crystal structure, the light extraction efficiency can be improved by reducing the difference in refractive index of the medium through which light passes.

Meanwhile, the body 210 may include a first electrode 252 and a second electrode 254. The first electrode 252 and the second electrode 254 may be electrically connected to the light source unit 220 to supply power to the light source unit 220.

The first electrode 252 and the second electrode 254 are electrically separated from each other, and may reflect light generated from the light source unit 220 to increase light efficiency, and also externally generate heat generated from the light source unit 220. Can be discharged.

In FIG. 17, the light source unit 220 is installed on the second electrode 254, and the first electrode 252 is bonded with a wire. However, the light source unit 220 is not limited thereto, and the light source unit 220 and the first electrode 252 are not limited thereto. The second electrode 254 may be electrically connected by any one of a wire bonding method, a flip chip method, or a die bonding method.

The first electrode 252 and the second electrode 254 are made of a metal material, for example, titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), and tantalum ( Ta, platinum (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium ( Ge), hafnium (Hf), ruthenium (Ru), iron (Fe) may include one or more materials or alloys. In addition, the first electrode 252 and the second electrode 254 may be formed to have a single layer or a multilayer structure, but is not limited thereto.

The encapsulant 230 may be filled in the cavity and may include the phosphor 240. The encapsulant 230 may be formed of transparent silicone, epoxy, and other resin materials, and may be formed by filling in a cavity and then ultraviolet or thermal curing.

The phosphor 240 may be selected according to the wavelength of light emitted from the light source unit 220 so that the light emitting device package 200 may implement white light.

The phosphor 240 included in the encapsulant 230 may be a blue light emitting phosphor, a cyan light emitting phosphor, a green light emitting phosphor, a yellow green light emitting phosphor, a yellow light emitting phosphor, a yellow red light emitting phosphor, according to a wavelength of light emitted from the light source 220. One of an orange light emitting phosphor and a red light emitting phosphor may be applied.

That is, the phosphor 240 may be excited by the light having the first light emitted from the light source unit 220 to generate the second light. For example, when the light source unit 220 is a blue light emitting diode and the phosphor 240 is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and blue light and blue light generated from the blue light emitting diode As the yellow light generated by excitation is mixed, the light emitting device package 200 may provide white light.

Similarly, when the light source unit 220 is a green light emitting diode, a magenta phosphor or a blue and red phosphor 240 is mixed. When the light source unit 220 is a red light emitting diode, a cyan phosphor or a blue and green phosphor is used. For example, the case of mixing.

The phosphor 240 may be a known one such as YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride, or phosphate.

FIG. 18A is a perspective view illustrating a lighting apparatus according to an embodiment, and FIG. 18B is a cross-sectional view illustrating a cross section along AA ′ of the lighting apparatus of FIG. 18A.

Hereinafter, in order to describe the shape of the lighting apparatus 300 according to the embodiment in more detail, the longitudinal direction (Z) of the lighting apparatus 300, the horizontal direction (Y) perpendicular to the longitudinal direction (Z), and the length The height direction X perpendicular to the direction Z and the horizontal direction Y will be described.

That is, FIG. 18B is a cross-sectional view of the lighting device 300 of FIG. 18A cut in the plane of the longitudinal direction Z and the height direction X, and viewed in the horizontal direction Y. As shown in FIG.

18A and 18B, the lighting device 300 may include a body 310, a cover 330 fastened to the body 310, and a closing cap 350 positioned at both ends of the body 310. have.

The lower surface of the body 310 is fastened to the light emitting device module 340, the body 310 is conductive and so as to emit heat generated from the light emitting device 344 to the outside through the upper surface of the body 310 It may be formed of a metal material having an excellent heat dissipation effect.

The light emitting device package 344 may be mounted on the PCB substrate 342 in multiple colors and in multiple rows to form an array. The light emitting device package 344 may be mounted at the same interval or may be mounted at various separation distances as necessary to adjust brightness. Can be. The PCB substrate 342 may be a MCPCB (Metal Core PCB) or a PCB made of FR4.

Meanwhile, the light emitting device included in the light emitting device package 344 includes a light extracting structure in one region of the first conductive semiconductor layer, and the light extracting structure is lower than the refractive index of the first conductive semiconductor layer and larger than the refractive index of the encapsulant. Including the photonic crystal structure of the, it is possible to increase the light extraction efficiency by reducing the difference in the refractive index of the medium passing light.

The cover 330 may be formed in a circular shape to surround the lower surface of the body 310, but is not limited thereto.

The cover 330 protects the light emitting device module 340 from the outside and the like. In addition, the cover 330 may include diffusing particles to prevent the glare of the light generated from the light emitting device package 344 and to uniformly emit light to the outside, and may also include at least one of an inner surface and an outer surface of the cover 330. A prism pattern or the like may be formed on either side. In addition, a phosphor may be applied to at least one of an inner surface and an outer surface of the cover 330.

On the other hand, since the light generated from the light emitting device package 344 is emitted to the outside through the cover 330, the cover 330 should be excellent in light transmittance, and has sufficient heat resistance to withstand the heat generated from the light emitting device 344 It should be, the cover 330 is preferably formed of a material containing polyethylene terephthalate (PET), polycarbonate (PC) or polymethyl methacrylate (PMMA).

Closing cap 350 is located at both ends of the body 310 may be used for sealing the power supply (not shown). In addition, the closing cap 350 is formed with a power pin 352, the lighting device 300 according to the embodiment can be used immediately without a separate device to the terminal from which the existing fluorescent lamps are removed.

19 is an exploded perspective view of a liquid crystal display according to an embodiment.

FIG. 19 illustrates an edge-light method, and the liquid crystal display device 400 may include a liquid crystal display panel 410 and a backlight unit 470 for providing light to the liquid crystal display panel 410.

The liquid crystal display panel 410 may display an image using light provided from the backlight unit 470. The liquid crystal display panel 410 may include a color filter substrate 412 and a thin film transistor substrate 414 facing each other with the liquid crystal interposed therebetween.

The color filter substrate 412 may implement a color of an image displayed through the liquid crystal display panel 410.

The thin film transistor substrate 414 is electrically connected to the printed circuit board 418 on which a plurality of circuit components are mounted through the driving film 417. The thin film transistor substrate 414 may apply a driving voltage provided from the printed circuit board 418 to the liquid crystal in response to a driving signal provided from the printed circuit board 418.

The thin film transistor substrate 414 may include a thin film transistor and a pixel electrode formed of a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 470 may convert the light provided from the light emitting device module 420, the light emitting device module 420 into a surface light source, and provide the light guide plate 430 to the liquid crystal display panel 410. Reflective sheet reflecting the light emitted to the light guide plate 430 to the plurality of films 450, 466, 464 and the light guide plate 430 to uniform the luminance distribution of the light provided from the light source 430 and to improve vertical incidence ( 440).

The light emitting device module 420 may include a PCB substrate 422 such that a plurality of light emitting device packages 424 and a plurality of light emitting device packages 424 may be mounted to form an array.

As described with reference to FIGS. 1 and 3, the light emitting device included in the light emitting device package 424 may include a light extraction structure to increase a critical angle, thereby preventing total reflection to improve light extraction efficiency.

On the other hand, the backlight unit 470 is a diffusion film 466 for diffusing light incident from the light guide plate 430 toward the liquid crystal display panel 410, and a prism film 450 for condensing the diffused light to improve vertical incidence. It may be configured as), and may include a protective film 464 for protecting the prism film 450.

20 is an exploded perspective view of a liquid crystal display according to an embodiment. However, the parts shown and described in FIG. 19 will not be repeatedly described in detail.

20 is a direct view, the liquid crystal display 500 may include a liquid crystal display panel 510 and a backlight unit 570 for providing light to the liquid crystal display panel 510.

Since the liquid crystal display panel 510 is the same as that described with reference to FIG. 19, a detailed description thereof will be omitted.

The backlight unit 570 includes a plurality of light emitting device modules 523, a reflective sheet 524, a lower chassis 530 in which the light emitting device modules 523 and the reflective sheet 524 are accommodated, and an upper portion of the light emitting device module 523. It may include a diffusion plate 540 and a plurality of optical film 560 disposed in the.

The light emitting device module 523 may include a PCB substrate 521 such that a plurality of light emitting device packages 522 and a plurality of light emitting device packages 522 are mounted to form an array.

The light emitting device package 522 may include a light emitting device according to an embodiment, and may increase light extraction efficiency by reducing a difference in refractive index of a medium through which light passes.

The reflective sheet 524 reflects the light generated from the light emitting device package 522 in the direction in which the liquid crystal display panel 510 is positioned to improve light utilization efficiency.

Meanwhile, the light generated by the light emitting device module 523 is incident on the diffusion plate 540, and the optical film 560 is disposed on the diffusion plate 540. The optical film 560 includes a diffusion film 566, a prism film 550, and a protective film 564.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

In addition, the above description has been made with reference to the embodiment, which is merely an example, and is not intended to limit the present invention. Those skilled in the art to which the present invention pertains will be illustrated as above without departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

110: substrate 120: reflective layer
130: passivation 140: second conductive semiconductor layer
150: active layer 160: first conductive semiconductor layer
170: light extraction control layer 180: translucent electrode layer
190: electrode

Claims (9)

And a light emitting structure including an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer.
One region of the first conductive semiconductor layer includes a light extraction structure having an uneven structure,
The light extracting structure includes a photonic crystal structure, and the refractive index of the photonic crystal structure is smaller than the refractive index of the first conductive semiconductor layer. The method of claim 1,
And the photonic crystal structure is formed on the uneven shape of the light extraction structure. The method of claim 1,
The photonic crystal structure,
SiO, Al 2 O 3 , TiO 2 , TiO, Ti 2 O 3 , HfO 2 , Ta 2 O 5 , ZrO 2 , Y 2 O 3 , CeO 2 , Gd 2 O 3 , Sm 2 O 3 , MgO, ZnO, NiO, CeF 3, BaTiO 3, PrTiO 3, Zn1-xMgxO, Zn1-yBeO, Zn1-x-yMgxBeyO, Zn1-zCdzO, ITO, SiNx, MgAl 2 O 4, AlON, CeF 3, PbF 2, LaF 3 of at least Light emitting element which is one material. The method of claim 1,
The photonic crystal structure,
1.5? A light emitting device having a refractive index of 2.3. The method of claim 1,
The photonic crystal structure,
450 nm? Light emitting elements arranged at intervals of 600 nm. A light emitting structure on the substrate, the light emitting structure having an active layer between the first conductive semiconductor layer and the second conductive semiconductor layer;
A translucent electrode layer on the light emitting structure; And
And a light extraction control layer disposed between the first conductive semiconductor layer and the light transmissive electrode layer and having a refractive index smaller than that of the first conductive semiconductor layer. The method of claim 6,
The light extraction control layer,
1.5? A light emitting element having a refractive index of 2.3. The method of claim 6,
The light extraction control layer,
1Å A light emitting device having a thickness of 300 μm. The method of claim 6,
The light extraction control layer,
SiO, Al 2 O 3 , TiO 2 , TiO, Ti 2 O 3 , HfO 2 , Ta 2 O 5 , ZrO 2 , Y 2 O 3 , CeO 2 , Gd 2 O 3 , Sm 2 O 3 , MgO, ZnO, NiO, CeF 3, BaTiO 3, PrTiO 3, Zn1-xMgxO, Zn1-yBeO, Zn1-x-yMgxBeyO, Zn1-zCdzO, ITO, SiNx, MgAl 2 O 4, AlON, CeF 3, PbF 2, LaF 3 of at least One light emitting device.
KR1020100100416A 2010-10-14 2010-10-14 Light emitting device KR20120038776A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020100100416A KR20120038776A (en) 2010-10-14 2010-10-14 Light emitting device

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Application Number Priority Date Filing Date Title
KR1020100100416A KR20120038776A (en) 2010-10-14 2010-10-14 Light emitting device

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KR20120038776A true KR20120038776A (en) 2012-04-24

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20140059424A (en) * 2012-11-08 2014-05-16 엘지이노텍 주식회사 Light emitting device, light emitting device package, and light unit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20140059424A (en) * 2012-11-08 2014-05-16 엘지이노텍 주식회사 Light emitting device, light emitting device package, and light unit

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