KR20140096846A - Light emitting device - Google Patents

Light emitting device Download PDF

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Publication number
KR20140096846A
KR20140096846A KR1020130009971A KR20130009971A KR20140096846A KR 20140096846 A KR20140096846 A KR 20140096846A KR 1020130009971 A KR1020130009971 A KR 1020130009971A KR 20130009971 A KR20130009971 A KR 20130009971A KR 20140096846 A KR20140096846 A KR 20140096846A
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KR
South Korea
Prior art keywords
light emitting
layer
emitting device
semiconductor layer
buffer layer
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KR1020130009971A
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Korean (ko)
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KR102019745B1 (en
Inventor
강현오
김태준
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엘지이노텍 주식회사
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Priority to KR1020130009971A priority Critical patent/KR102019745B1/en
Publication of KR20140096846A publication Critical patent/KR20140096846A/en
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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
    • H01L33/14—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 carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
    • H01L33/145—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 carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure with a current-blocking structure
    • 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
    • H01L33/12—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 stress relaxation structure, e.g. buffer layer
    • 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
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of group III and group V of the periodic system
    • H01L33/32—Materials of the light emitting region containing only elements of group III and group V of the periodic system containing nitrogen

Abstract

According to an embodiment of the present invention, a light emitting device comprises a substrate; a first semiconductor layer disposed on the substrate; an active layer disposed on the first semiconductor layer; an electron blocking layer disposed on the active layer; a second semiconductor layer disposed on the electron blocking layer and to prevent electrons supplied by the first semiconductor layer from leaking to the second semiconductor layer; and a buffering layer disposed between the electron blocking layer and the second semiconductor layer, having a smaller energy band gap than that of the electron blocking layer, and changing the energy band gap according to the height thereof.

Description

LIGHT EMITTING DEVICE AND LIGHT EMITTING DEVICE PACKAGE CONTAINING THE SAME

An embodiment relates to a light emitting device and a light emitting device package including the same.

Light Emitting Diode (LED) is a device that converts electrical signals into light by using the characteristics of compound semiconductors. It is widely used in household appliances, remote control, electric signboard, display, and various automation devices. There is a trend.

When a forward voltage is applied to the light emitting device, electrons in the n-layer and holes in the p-layer are coupled to emit energy corresponding to the energy gap between the conduction band and the valance band. It is mainly emitted in the form of heat or light, and when emitted in the form of light, it becomes an LED.

Nitride semiconductors have attracted great interest in the development of optical devices and high output electronic devices due to their high thermal stability and wide band gap energy. Particularly, blue light emitting devices, green light emitting devices, ultraviolet (UV) light emitting devices, and the like using nitride semiconductors have been commercialized and widely used.

The luminescent element may be distorted due to lattice mismatch between a plurality of layers therein. Therefore, it is necessary to study a method of solving the lattice mismatching while maintaining the optical and electrical characteristics.

The light emitting device package is manufactured by manufacturing a light emitting device on a substrate, separating the light emitting device chip through dieseparation, which is a sawing process, and then diebonding the light emitting device chip to a package body. Wire bonding and molding can be performed, and the test can proceed.

An embodiment of the present invention provides a light emitting device in which a buffer layer containing indium is disposed on an electron blocking layer to minimize defects due to lattice mismatch, thereby increasing light efficiency.

A light emitting device according to an embodiment of the present invention includes a substrate; A first semiconductor layer disposed on a substrate; An active layer disposed on the first semiconductor layer; An electron blocking layer disposed on the active layer; A second semiconductor layer disposed on the electron blocking layer and configured to restrict leakage of electrons supplied by the first semiconductor layer into the second semiconductor layer; And a buffer layer which is disposed between the electron blocking layer and the second semiconductor layer and has an energy band gap smaller than that of the electron blocking layer and whose energy band gap varies with height.

The light emitting device and the light emitting device package of the various embodiments of the present invention have one or more of the following effects.

The light emitting device according to one embodiment includes a buffer layer, thereby improving the warpage and minimizing defects.

The light emitting device according to one embodiment can change the energy band of the buffer layer according to the height, thereby minimizing the piezoelectric effect due to the lattice mismatch.

1 is a cross-sectional view illustrating a light emitting device according to an embodiment,
2 is a view showing an energy band gap of a light emitting device according to an embodiment,
3 is a view showing an energy band gap calculated through an experiment of a light emitting device according to an embodiment,
FIG. 4 is a graph showing the internal quantum efficiency of the light emitting device according to one embodiment,
5A and 5B are a perspective view and a cross-sectional view of a light emitting device package including a light emitting device according to an embodiment,
6A is a perspective view illustrating a lighting device including a light emitting device package according to an embodiment,
FIG. 6B is a cross-sectional view illustrating a lighting device including a light emitting device package according to an embodiment,
7 is a conceptual view illustrating a liquid crystal display device including a light emitting device package according to an embodiment,
8 is a conceptual view illustrating a liquid crystal display device including a light emitting device package according to an embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions. The elements can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

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

Further, the angle and direction mentioned in the description of the structure of the light emitting device in the embodiment are based on those shown in the drawings. In the description of the structure of the light emitting device in the specification, reference points and positional relationship with respect to angles are not explicitly referred to, refer to the related drawings.

Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view illustrating a light emitting device according to an embodiment, and FIG. 2 is a diagram illustrating an energy band gap of the light emitting device according to one embodiment.

1, a light emitting device 100 according to an embodiment includes a substrate 110, a first semiconductor layer 132 disposed on the substrate 110, an active layer 130 disposed on the first semiconductor layer 132, An electron blocking layer 140 disposed on the active layer 134 and limiting the leakage of electrons supplied by the first semiconductor layer to the second semiconductor layer, A buffer layer disposed between the second semiconductor layer 136 and the electron blocking layer 140 and the second semiconductor layer 136 and having an energy band gap smaller than that of the electron blocking layer 140, 150).

The substrate 110 may be disposed under the first semiconductor layer 132. The substrate 110 may support the first semiconductor layer 132. The substrate 110 may receive heat from the first semiconductor layer 132. The substrate 110 may have optically transmissive properties. For example, the substrate 110 may include, but is not limited to, sapphire (Al2O3). The substrate 110 may have a light transmitting property when it is formed using a light transmitting material or a material having a certain thickness or less, but the present invention is not limited thereto. The refractive index of the substrate 110 is preferably smaller than the refractive index of the first semiconductor layer 132 for the purpose of light extraction efficiency, but is not limited thereto.

The substrate 110 may be formed of a semiconductor material, for example, Si, Ge, GaAs, ZnO, SiC, It can be implemented with a carrier wafer such as a silicon germanium (SiGe), gallium nitride (GaN), gallium (ⅲ) oxide (Ga 2 O 3).

The substrate 110 may be formed of a conductive material. (Au), nickel (Ni), tungsten (W), molybdenum (Mo), copper (Cu), aluminum (Al), tantalum (Ag), platinum (Pt), and chromium (Cr), or may be formed of two or more alloys, and two or more of the above materials may be laminated. When the substrate 110 is formed of a metal, it is possible to facilitate the emission of heat generated from the light emitting device, thereby improving the thermal stability of the light emitting device.

The substrate 110 may have a PSS (Patterned Substrate) structure on its upper surface in order to enhance light extraction efficiency, but the present invention is not limited thereto. The substrate 110 facilitates the emission of heat generated in the light emitting device 100, thereby improving the thermal stability of the light emitting device 100. The substrate 110 may have a layer which mitigates the difference in lattice constant between the first semiconductor layer 132 and the first semiconductor layer 132 due to a difference in lattice constant.

The first semiconductor layer 132 may be disposed on the substrate 110. The first semiconductor layer 132 may be disposed on a buffer layer (not shown) to match the lattice constant difference with the substrate 110, but is not limited thereto. Although the first semiconductor layer 132 may be grown on the substrate 110, the first semiconductor layer 132 is not limited to a horizontal type light emitting device and may be applied to a vertical type light emitting device.

The first semiconductor layer 132 may be formed of an n-type semiconductor layer. For example, when the light emitting device 100 emits blue light, the n-type semiconductor layer may be formed of, for example, In x Al y Ga 1-xy N (0 = x = 1, 0 = y = (AlN), AlGaN (Indium Gallium Nitride), InGaN (Indium Gallium Nitride), InN (Indium Nitride), InAlGaN , AlInN, and the like. The first semiconductor layer 132 may be doped with an n-type dopant such as, for example, silicon (Si), germanium (Ge), tin (Sn), selenium (Se) or tellurium (Te).

The first semiconductor layer 132 may be supplied with power from the outside. The first semiconductor layer 132 may provide electrons to the active layer 134.

The active layer 134 may be disposed on the first semiconductor layer 132. The active layer 134 may be disposed between the second semiconductor layer 136 and the first semiconductor layer 132.

The active layer 134 may be formed of a semiconductor material. The active layer 134 may be formed of a single or multi-well structure or the like using a compound semiconductor material of Group 3-V group elements. The active layer 134 may be formed of a nitride semiconductor. For example, the active layer 134 may include gallium nitride (GaN), indium gallium nitride (InGaN), and indium gallium nitride (InAlGaN).

When the active layer 134 emits blue light, for example, the active layer 134 has a composition formula of In x Al y Ga 1 -x- y N (0 = x = 1, 0 = y = 1, 0 = x + having a well layer (not shown), and in a Al b Ga 1 -a- b N (0 = a = 1, 0 = b = 1, 0 = a + b = 1) when the barrier layer (not shown having a composition formula of ), But is not limited thereto. The well layer (not shown) may be formed of a material having a band gap smaller than the band gap of the barrier layer (not shown).

The active layer 134 may be formed by alternately stacking a plurality of well layers (not shown) and a barrier layer (not shown). The active layer 134 may include a plurality of well layers (not shown) to maximize optical efficiency.

The well layer (not shown) may have a smaller energy bandgap than the barrier layer (not shown). The well layer (not shown) may have a smaller energy bandgap than the first semiconductor layer 132. The well layer (not shown) may have a continuous energy level of the carrier.

The second semiconductor layer 136 may be formed on the active layer 134. The second semiconductor layer 136 may be formed of a p-type semiconductor layer doped with a p-type dopant. When the light emitting device emits light of a blue wavelength, the second semiconductor layer 136 is formed of In x Al y Ga 1 -x- y N (0 = x = 1, 0 = y = 1, 0 = x + y (AlN), AlGaN (Indium Gallium Nitride), InGaN (indium gallium nitride), InN (indium nitride), InAlGaN, and AlInN And a p-type dopant such as magnesium (Mg), zinc (Zn), calcium (Ca), strontium (Sr), barium (Ba) or the like can be doped.

The first semiconductor layer 132, the active layer 134 and the second semiconductor layer 136 may be formed using a metal organic chemical vapor deposition (MOCVD) method, a chemical vapor deposition (CVD) method, a plasma May be formed by a method such as chemical vapor deposition (PECVD), molecular beam epitaxy (MBE), or hydride vapor phase epitaxy (HVPE) It is not limited.

The doping concentration of the conductive dopant in the first semiconductor layer 132 and the second semiconductor layer 136 may be uniform or non-uniform, but is not limited thereto.

When the light emitting device 100 is a horizontal type light emitting diode, a first electrode (not shown) may be disposed in one region of the first semiconductor layer 132. The first electrode (not shown) may be electrically connected to the first semiconductor layer 132. The first electrode (not shown) may transmit an external power source to the first semiconductor layer 132.

A second electrode (not shown) may be disposed in one region of the second semiconductor layer 136. The second electrode (not shown) may be electrically connected to the second semiconductor layer 136. The second electrode (not shown) may provide an external power supply to the second semiconductor layer 136.

The first electrode (not shown) and the second electrode (not shown) may be formed of a conductive material such as indium (In), cobalt (Co), silicon (Si), germanium (Ge), gold (Au), palladium ), Platinum (Pt), ruthenium (Ru), rhenium (Re), magnesium (Mg), zinc (Zn), hafnium (Hf), tantalum (Ta), rhodium (Ti), Ag, Cr, Mo, Nb, Al, Ni, Cu, and WTi, Or a multi-layered structure using a metal or an alloy selected from the group consisting of a metal, a metal, and an alloy.

A transparent electrode layer (not shown) may be disposed between the second electrode (not shown) and the second semiconductor layer 136. A transparent electrode layer (not shown) may be in ohmic contact with the second semiconductor layer 136. The transparent electrode layer (not shown) may include one layer or a plurality of layers alternately stacked. The transparent electrode layer (not shown) may selectively include a light-transmitting conductive layer and a metal layer. The transparent electrode layer (not shown) can smoothly inject carriers into the second semiconductor layer 136.

For example, the transparent electrode layer (not shown) may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IrO x, RuO x, RuO x / ITO, Ni, Ag, Ni / IrO x / Au, And at least one of Ni / IrO x / Au / ITO.

The electron blocking layer 140 may be disposed between the active layer 134 and the second semiconductor layer 136. The Electron Blocking Layer (EBL) 140 may include aluminum. For example, the electron blocking layer 140 may comprise aluminum gallium nitride (AlGaN).

The electron blocking layer 140 may comprise aluminum indium gallium nitride (Al x In y GaN). As the content of aluminum in the electron blocking layer 140 increases, the energy band gap of the electron blocking layer 140 increases and the plane lattice constant decreases. As the indium content of the electron blocking layer 140 increases, the energy bandgap decreases and the plane lattice constant increases.

The light emitting structure 130 and the electron blocking layer 140 may include aluminum to generate a pressure that is laterally contracted in a lamination relationship with another layer. A piezoelectric field effect may occur due to the internal laminating relationship between the light emitting structure 130 and the electron blocking layer 140.

The piezoelectric field effect may occur due to the pressure due to the difference in lattice constant between the first semiconductor layer 132, the active layer 134, the second semiconductor layer 136, and the electron blocking layer 140. The light emitting device 100 may have a defect due to a piezoelectric field effect, and a leakage current may be generated.

The buffer layer 150 may be disposed between the electron blocking layer 140 and the second semiconductor layer 136. The buffer layer 150 may comprise indium gallium nitride (InGaN). The energy bandgap of the buffer layer 150 may vary with height.

The buffer layer 150 may have a smaller energy bandgap than the electron blocking layer 140. The buffer layer 150 can change the content of indium depending on the height. The buffer layer 150 may have a parabolic energy band.

Referring to FIG. 2, the buffer layer 150 may have a parabolic energy band. The buffer layer 150 may be in the form of a conductive band whose convex portion of the parabola faces downward.

The buffer layer 150 may have a parabolic shape by varying the content of indium depending on its height. The slope of the energy band can be gradually reduced until the buffer layer 150 reaches the middle in the height direction on the lower surface. The slope of the energy band can gradually increase until the buffer layer 150 reaches the upper surface in the middle in the height direction.

The content of indium may gradually increase until the buffer layer 150 reaches the middle in the height direction on the lower surface. The content of indium may gradually decrease until the buffer layer 150 reaches the upper surface in the middle in the height direction.

The buffer layer 150 contains indium and may have a pressure that expands laterally.

The buffer layer 150 may have a thickness of 10 nm to 48 nm. When the thickness is less than 10 nm, the buffer layer 150 may be too thin to allow a pressure to be laterally expanded, and may not compensate the lateral shrinking force of the light emitting structure 130 and the electron blocking layer 140, The light extracting characteristic can be lowered, and the degree of the holes reaching the active layer 134 can be remarkably reduced, and the recombination rate of electrons and holes can be lowered.

FIG. 3 is a graph illustrating an experimentally calculated energy band gap of the light emitting device 100 of one embodiment.

In the graph shown in Fig. 3, the abscissa is the height (nm) of the layer and the ordinate is the energy (eV). 3 may be any one of a plurality of well layers of the active layer 132. In this case, In the well layer of the active layer 132, recombination of electrons and holes may occur.

The energy band of the light emitting element can be distorted in accordance with the piezoelectric effect. If the defect due to the piezoelectric effect is too severe, the light emitting device may not be matched due to the deformation of the conduction band lower well layer and the balance band upper well layer. When the piezoelectric effect is excessively generated, the positions of the highest density of electrons and the highest density of holes are not matched with each other, so that recombination of electrons and holes may be difficult.

When the graph of FIG. 3 is confirmed, it can be confirmed that the portion having the highest density of electrons and holes in the well layer of the active layer 134 is overlapped.

4 is a graph showing the internal quantum efficiency (IQE) of the light emitting device of one embodiment.

In the graph of Fig. 4, the abscissa is the current value and the ordinate is the internal quantum efficiency.

Referring to FIG. 4, the purple line shows a change in the internal quantum efficiency of the light emitting device without the buffer layer inserted therein, and the blue line shows the change in the internal quantum efficiency of the light emitting device with the buffer layer inserted.

In the case of the light emitting device in which the buffer layer is not inserted, it can be seen that the quantum efficiency decreases gradually as the current increases. However, it can be confirmed that the internal quantum efficiency is maintained in the light emitting device inserted with the buffer layer.

5A is a perspective view illustrating a light emitting device package 300 according to an exemplary embodiment of the present invention, and FIG. 5B is a cross-sectional view illustrating a light emitting device package 300 according to another exemplary embodiment.

5A and 5B, the light emitting device package 300 according to the embodiment includes a body 310 having a cavity, first and second electrodes 340 and 350 mounted on the body 310, A light emitting device 320 electrically connected to the two electrodes, and an encapsulant 330 formed in the cavity. The encapsulant 330 may include a phosphor (not shown).

The body 310 is made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), liquid crystal polymer (PSG), polyamide 9T ), new geo-isotactic polystyrene (SPS), metal materials, sapphire (Al 2 O 3), beryllium oxide (BeO), is a printed circuit board (PCB, printed circuit board), it may be formed of at least one of ceramic. The body 310 may be formed by injection molding, etching, or the like, but is not limited thereto.

The inner surface of the body 310 may be formed with an inclined surface. The reflection angle of the light emitted from the light emitting device 320 can be changed according to the angle of the inclined surface, and thus the directivity angle of the light emitted to the outside can be adjusted.

The shape of the cavity formed in the body 310 may be circular, square, polygonal, elliptical, or the like, and may have a curved shape, but the present invention is not limited thereto.

The encapsulant 330 may be filled in the cavity and may include a phosphor (not shown). The encapsulant 330 may be formed of transparent silicone, epoxy, and other resin materials. The encapsulant 330 may be formed in such a manner that the encapsulant 330 is filled in the cavity and then cured by ultraviolet rays or heat.

The phosphor (not shown) may be selected according to the wavelength of the light emitted from the light emitting device 320, so that the light emitting device package 300 can realize white light.

The fluorescent material (not shown) included in the encapsulant 330 may be a blue light emitting phosphor, a blue light emitting fluorescent material, a green light emitting fluorescent material, a yellow green light emitting fluorescent material, a yellow light emitting fluorescent material, Fluorescent material, orange light-emitting fluorescent material, and red light-emitting fluorescent material may be applied.

The phosphor (not shown) may be excited by the light having the first light emitted from the light emitting device 320 to generate the second light. For example, when the light emitting element 320 is a blue light emitting diode and the phosphor (not shown) is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, As the yellow light generated by excitation by blue light is mixed, the light emitting device package 300 can provide white light.

When the light emitting element 320 is a green light emitting diode, the magenta phosphor or the blue and red phosphors (not shown) are mixed. When the light emitting element 320 is a red light emitting diode, a cyan phosphor or a mixture of blue and green phosphors For example.

The phosphor (not shown) may be a known one such as YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride or phosphate.

The first electrode 340 and the second electrode 350 may be mounted on the body 310. The first electrode 340 and the second electrode 350 may be electrically connected to the light emitting device 320 to supply power to the light emitting device 320.

The first electrode 340 and the second electrode 350 are electrically separated from each other and reflect light generated from the light emitting device 320 to increase light efficiency. The first electrode 340 and the second electrode 350 may discharge heat generated from the light emitting device 320 to the outside.

The light emitting device 320 is mounted on the first electrode 340 but the present invention is not limited thereto and the light emitting device 320 and the first electrode 340 and the second electrode 350 may be wire bonded ) Method, a flip chip method, or a die bonding method.

The first electrode 340 and the second electrode 350 may be formed of a metal material such as titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), tantalum ), Platinum (Pt), tin (Sn), silver (Ag), phosphorous (P), aluminum (Al), indium (In), palladium (Pd), cobalt ), Hafnium (Hf), ruthenium (Ru), and iron (Fe). The first electrode 340 and the second electrode 350 may have a single-layer structure or a multi-layer structure, but the present invention is not limited thereto.

The light emitting device 320 is mounted on the first electrode 340 and may be a light emitting device that emits light such as red, green, blue, or white, or a UV (Ultra Violet) However, the present invention is not limited thereto. One or more light emitting elements 320 may be mounted.

The light emitting device 320 is applicable to both a horizontal type whose electrical terminals are all formed on the upper surface, a vertical type formed on the upper and lower surfaces, or a flip chip.

The light emitting device package 300 may include a light emitting device.

A light guide plate, a prism sheet, a diffusion sheet, and the like, which are optical members, may be disposed on a light path of the light emitting device package 300.

The light emitting device package 300, the substrate, and the optical member may function as a light unit. Another embodiment may be implemented as a display device, an indicating device, a lighting system including a light emitting device (not shown) or a light emitting device package 300, for example, the lighting system may include a lamp, a streetlight .

FIG. 6A is a perspective view showing an illumination system 400 including a light emitting device according to an embodiment, and FIG. 6B is a cross-sectional view showing a D-D 'cross-section of the illumination system of FIG. 6A.

6B is a cross-sectional view of the illumination system 400 of FIG. 6A cut in the longitudinal direction Z and the height direction X and viewed in the horizontal direction Y. FIG.

6A and 6B, the lighting system 400 may include a body 410, a cover 430 coupled to the body 410, and a finishing cap 450 positioned at either end of the body 410 have.

The light emitting device module 443 is coupled to a lower surface of the body 410. The body 410 is electrically connected to the light emitting device package 444 through the upper surface of the body 410, And may be formed of a metal material having excellent heat dissipation effect, but is not limited thereto.

The light emitting device package 444 includes a light emitting element (not shown).

The light emitting device package 444 may be mounted on the substrate 442 in a multi-color, multi-row manner to form a module. The light emitting device package 444 may be mounted at equal intervals or may be mounted with various spacings as needed. As the substrate 442, MCPCB (Metal Core PCB) or FR4 PCB can be used.

The cover 430 may be formed in a circular shape so as to surround the lower surface of the body 410, but is not limited thereto.

The cover 430 can protect the internal light emitting element module 443 from foreign substances or the like. The cover 430 may include diffusion particles to prevent glare of light generated in the light emitting device package 444 and uniformly emit light to the outside, and may include at least one of an inner surface and an outer surface of the cover 430 A prism pattern or the like may be formed on the surface. Further, the phosphor may be coated on at least one of the inner surface and the outer surface of the cover 430.

The light generated from the light emitting device package 444 is emitted to the outside through the cover 430 so that the cover 430 should have excellent light transmittance and sufficient heat resistance to withstand the heat generated from the light emitting device package 444 The cover 430 may be made of a material including polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), or the like .

The finishing cap 450 is located at both ends of the body 410 and can be used for sealing the power supply unit (not shown). The finishing cap 450 is formed with the power pin 452, so that the lighting system 400 according to the embodiment can be used immediately without a separate device on the terminal from which the conventional fluorescent lamp is removed.

7 is an exploded perspective view of a liquid crystal display device including a light emitting device according to an embodiment.

7, 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 in an edge-light manner.

The liquid crystal display panel 510 can display an image using the light provided from the backlight unit 570. The liquid crystal display panel 510 may include a color filter substrate 512 and a thin film transistor substrate 514 facing each other with a liquid crystal therebetween.

The color filter substrate 512 can realize the color of an image to be displayed through the liquid crystal display panel 510.

The thin film transistor substrate 514 is electrically connected to a printed circuit board 518 on which a plurality of circuit components are mounted via a driving film 517. The thin film transistor substrate 514 may apply a driving voltage provided from the printed circuit board 518 to the liquid crystal in response to a driving signal provided from the printed circuit board 518. [

The thin film transistor substrate 514 may include a thin film transistor and a pixel electrode formed as a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 570 includes a light emitting device module 520 for outputting light, a light guide plate 530 for changing the light provided from the light emitting module 520 into a surface light source to provide the light to the liquid crystal display panel 510, A plurality of films 550, 560, and 564 that uniformly distribute the luminance of light provided from the light guide plate 530 and improve vertical incidence, and a reflective sheet (not shown) that reflects light emitted to the rear of the light guide plate 530 to the light guide plate 530 540).

The light emitting device module 520 may include a PCB substrate 522 to mount a plurality of light emitting device packages 524 and a plurality of light emitting device packages 524 to form a module.

The light emitting device package 524 includes a light emitting element (not shown).

The backlight unit 570 includes a diffusion film 566 for diffusing light incident from the light guide plate 530 toward the liquid crystal display panel 510 and a prism film 550 for enhancing vertical incidence by condensing the diffused light And may include a protective film 564 for protecting the prism film 550.

8 is an exploded perspective view of a liquid crystal display device including a light emitting device according to an embodiment. However, the parts shown and described in Fig. 7 are not repeatedly described in detail.

8 is a direct-view liquid crystal display device 600 according to the embodiment. The liquid crystal display device 600 may include a liquid crystal display panel 610 and a backlight unit 670 for providing light to the liquid crystal display panel 610. Since the liquid crystal display panel 610 is the same as that described with reference to FIG. 7, a detailed description thereof will be omitted.

The backlight unit 670 includes a plurality of light emitting element modules 623, a reflective sheet 624, a lower chassis 630 in which the light emitting element module 623 and the reflective sheet 624 are accommodated, And a plurality of optical films 660 disposed on the diffuser plate 640.

The light emitting device module 623 may include a PCB substrate 621 to mount a plurality of light emitting device packages 622 and a plurality of light emitting device packages 622 to form a module.

The light emitting device package 622 includes a light emitting element (not shown).

The reflective sheet 624 reflects light generated from the light emitting device package 622 in a direction in which the liquid crystal display panel 610 is positioned, thereby improving light utilization efficiency.

The light emitted from the light emitting element module 623 is incident on the diffusion plate 640 and the optical film 660 is disposed on the diffusion plate 640. The optical film 660 is composed of a diffusion film 666, a prism film 650, and a protective film 664.

The configuration and the method of the embodiments described above are not limitedly applied, but the embodiments may be modified so that all or some of the embodiments are selectively combined so that various modifications can be made. .

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It should be understood that various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

100: Light emitting element
110: substrate
132: first semiconductor layer
134: active layer
136: second semiconductor layer
140: electron blocking layer
150: buffer layer

Claims (10)

Board;
A first semiconductor layer disposed on the substrate;
An active layer disposed on the first semiconductor layer;
An electron blocking layer disposed on the active layer and configured to restrict leakage of electrons supplied by the first semiconductor layer to the second semiconductor layer;
A second semiconductor layer disposed on the electron blocking layer; And
And a buffer layer disposed between the electron blocking layer and the second semiconductor layer and having an energy band gap smaller than that of the electron blocking layer and having an energy band gap varying with height. The method according to claim 1,
Wherein the buffer layer has a parabolic energy band. The method according to claim 1,
Wherein the slope of the energy band gradually decreases until the buffer layer reaches the middle in the height direction on the lower surface. The method of claim 3,
Wherein a slope of the energy band is gradually increased until the buffer layer reaches the upper surface in the middle in the height direction. The method according to claim 1,
Wherein the buffer layer comprises indium gallium nitride (InGaN). 6. The method of claim 5,
Wherein the buffer layer varies in indium (In) content depending on the height. 6. The method of claim 5,
Wherein the buffer layer gradually increases in indium content until reaching the middle in the height direction on the lower surface. 6. The method of claim 5,
Wherein the buffer layer gradually decreases in indium content until the buffer layer reaches the upper surface in the height direction. The method according to claim 1,
Wherein the buffer layer has a thickness of 10 nm to 48 nm. A light emitting device package comprising the light emitting device according to any one of claims 1 to 9.
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KR20160084033A (en) * 2015-01-05 2016-07-13 엘지이노텍 주식회사 Light emitting device

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KR20100003331A (en) * 2008-06-26 2010-01-08 서울옵토디바이스주식회사 Light emitting device and method of manufacturing the same
JP2010212657A (en) * 2009-03-06 2010-09-24 Chung Hoon Lee Light emitting device
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