KR102007273B1

KR102007273B1 - Light emitting device

Info

Publication number: KR102007273B1
Application number: KR1020130001177A
Authority: KR
Inventors: 문용태
Original assignee: 엘지이노텍 주식회사
Priority date: 2013-01-04
Filing date: 2013-01-04
Publication date: 2019-08-05
Also published as: KR20140092958A

Abstract

The light emitting device according to the embodiment of the present invention comprises a first semiconductor layer; A current injection layer disposed on the first semiconductor layer and including a plurality of injection well layers having an energy band gap smaller than that of the first semiconductor layer; An active layer disposed on the current injection layer; A second semiconductor layer disposed on the active layer; And a dispersion barrier layer disposed between the first semiconductor layer and the current injection layer, the dispersion well layer having an energy band gap smaller than the energy band gap of the first semiconductor layer, and a dispersion barrier layer having an energy band gap larger than the energy band gap of the first semiconductor layer. It includes; a current spreading layer comprising a layer.

Description

Light emitting device

An embodiment relates to a light emitting device.

LED (Light Emitting Diode) is a device that converts an electric signal into infrared, visible or light form by using the characteristics of compound semiconductor.It is used in home appliances, remote control, electronic signs, indicators, various automation devices, etc. LED's usage area is getting wider.

In general, miniaturized LEDs are made of a surface mount device type for direct mounting on a printed circuit board (PCB) board. Accordingly, LED lamps, which are used as display elements, are also being developed as surface mount device types. . Such a surface mounting element can replace a conventional simple lighting lamp, which is used as a lighting display for various colors, a character display and an image display.

LED semiconductors are grown through heterogeneous substrates such as sapphire or silicon carbide (SiC) having a hexagonal structure through metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).

The LED generates light by recombination of holes provided in the p-type semiconductor layer and electrons provided in the n-type semiconductor layer in the active layer. In the LED, improving the probability of recombination of holes and electrons in the active layer is an important issue for improving the light efficiency. In particular, it is important to maximize the light efficiency at 10 to 60A / cm ² within the driving range of commercialized products. In addition, there is a need to improve the efficiency efficiency (efficiency droop) by increasing the drive current density of the product.

The LED generates light by recombination of holes provided in the p-type semiconductor layer and electrons provided in the n-type semiconductor layer in the active layer. In the LED, improving the probability of recombination of holes and electrons in the active layer is an important issue for improving the light efficiency.

The embodiment provides a light emitting device having improved light efficiency.

The light emitting device according to the embodiment of the present invention comprises a first semiconductor layer; A current injection layer disposed on the first semiconductor layer and including a plurality of injection well layers having an energy band gap smaller than that of the first semiconductor layer; An active layer disposed on the current injection layer; A second semiconductor layer disposed on the active layer; And a dispersion barrier layer disposed between the first semiconductor layer and the current injection layer, the dispersion well layer having an energy band gap smaller than the energy band gap of the first semiconductor layer, and a dispersion barrier layer having an energy band gap larger than the energy band gap of the first semiconductor layer. And a current spreading layer comprising a layer.

In the light emitting device according to the exemplary embodiment of the present invention, a current dispersing layer is disposed between the first semiconductor layer and the current injection layer to diffuse current into the entire semiconductor layer, thereby maximizing the recombination rate of holes and electrons.

In the light emitting device according to the embodiment of the present invention, the dispersion well layer and the dispersion barrier layer are alternately stacked, so that electrons may be horizontally dispersed in the dispersion well layer so that holes and electrons may be recombined in a larger area of the active layer. .

In the light emitting device according to the exemplary embodiment of the present invention, a dispersion intermediate layer is disposed between the dispersion well layer and the dispersion barrier layer to reduce the instantaneous change in the energy band gap inside the current dispersion layer, thereby alleviating the stress between the layers.

In the light emitting device according to the exemplary embodiment of the present invention, a dispersion intermediate layer is disposed at a position in contact with the current injection layer of the dispersion barrier layer, thereby reducing the instantaneous change in the energy band gap between the dispersion barrier layer and the current injection layer, thereby reducing the stress between the layers. Can alleviate

1 is a cross-sectional view showing the structure of a light emitting device according to the 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 of a light emitting device according to an embodiment;
4 is a view showing an energy band gap of a light emitting device according to an embodiment;
5 is a view showing an energy band gap of a light emitting device according to an embodiment;
6 is a graph showing the content of aluminum and indium in the dispersion barrier layer of the light emitting device according to the embodiment;
7A is a perspective view showing a light emitting device package including a light emitting device of the embodiment;
7B is a cross-sectional view showing a light emitting device package including a light emitting device of the embodiment;
8A is a perspective view illustrating a lighting device including a light emitting device module according to an embodiment;
8B is a cross-sectional view showing a lighting apparatus including a light emitting device module according to an embodiment;
9 is an exploded perspective view illustrating a backlight unit including a light emitting device module according to an embodiment; and
10 is an exploded perspective view illustrating a backlight unit including a light emitting device module according to an embodiment.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various different forms, and only the embodiments make the disclosure of the present invention complete, and the general knowledge in the art to which the present invention belongs. It is provided to fully inform the person having the scope of the invention, which is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

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 are to be understood as including terms in different directions of the device in use or operation in addition to the directions shown in the figures. For example, when flipping a device shown in the figure, a device described as "below" or "beneath" of another device may be placed "above" of another device. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can also be oriented in other directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, “comprises” and / or “comprising” refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used in a sense that can be commonly understood by those skilled in the art. In addition, the terms defined in the commonly used dictionaries are not ideally or excessively interpreted unless they are specifically defined clearly.

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.

In addition, the angle and direction mentioned in the process of describing the structure of the light emitting device in the embodiment are based on those described in the drawings. In the description of the structure constituting the light emitting device in the specification, if the reference point and the positional relationship with respect to the angle is not clearly mentioned, reference is made to related drawings.

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

1 is a cross-sectional view showing the structure of a light emitting device according to the embodiment.

Referring to FIG. 1, the light emitting device 100 according to the exemplary embodiment of the present invention is disposed on the first semiconductor layer 110 and the first semiconductor layer 110, and has an energy band gap greater than that of the first semiconductor layer 110. A current injection layer 130 including a plurality of small injection well layers 132, an active layer 140 disposed on the current injection layer 130, a second semiconductor layer 150 disposed on the active layer 140, and The dispersion well layer 122 and the first semiconductor layer 110 disposed between the first semiconductor layer 110 and the current injection layer 130 and having an energy band gap smaller than the energy band gap of the first semiconductor layer 110. It may include a current spreading layer 120 including a dispersion barrier layer 124 having an energy band gap larger than the energy band gap of).

The substrate (not shown) may be disposed below the first semiconductor layer 110 or above the second semiconductor layer 150. The substrate (not shown) may support the first semiconductor layer 110 or the second semiconductor layer 150. The substrate (not shown) may receive heat from the first semiconductor layer 110 or the second semiconductor layer 150.

The substrate (not shown) may have a light transmissive property. For example, the substrate (not shown) may include sapphire (Al 2 O 3), but is not limited thereto. The substrate (not shown) may have a light transmissive property when using a light transmissive material or formed below a predetermined thickness, but is not limited thereto. The refractive index of the substrate (not shown) is preferably smaller than the refractive index of the first semiconductor layer 110 for light extraction efficiency, but is not limited thereto.

The substrate (not shown) may be formed of a semiconductor material according to an embodiment, for example, silicon (Si), germanium (Ge), gallium arsenide (GaAs), zinc oxide (ZnO), silicon carbide (SiC) It may be implemented as a carrier wafer such as silicon germanium (SiGe), gallium nitride (GaN), gallium (III) oxide (Ga ₂ O ₃ ).

The substrate (not shown) may be formed of a conductive material. According to the embodiment, the metal may be formed of, for example, gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), copper (Cu), aluminum (Al), tantalum (Ta), or silver. It may be formed of any one selected from (Ag), platinum (Pt), chromium (Cr) or formed of two or more alloys, and may be formed by stacking two or more of the above materials. When the substrate (not shown) is formed of a metal, it is possible to facilitate the emission of heat generated from the light emitting device to improve the thermal stability of the light emitting device.

The substrate (not shown) may include a patterned substrate (PSS) structure on an upper surface of the substrate to increase light extraction efficiency, but is not limited thereto. The substrate (not shown) may improve the thermal stability of the light emitting device 100 by facilitating the emission of heat generated from the light emitting device 100.

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

The first semiconductor layer 110 may be implemented as an n-type semiconductor layer. For example, when the light emitting device 100 emits light having a blue wavelength, the n-type semiconductor layer may be, for example, In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0). A semiconductor material having a composition formula of ≤ x + y ≤ 1, for example, gallium nitride (GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), indium nitride (InNN), and InAlGaN , AlInN and the like. For example, the first semiconductor layer 110 may be doped with n-type dopants such as silicon (Si), germanium (Ge), tin (Sn), selenium (Se), and tellurium (Te).

The first semiconductor layer 110 may receive power from the outside. The first semiconductor layer 110 may provide electrons to the active layer 140.

The active layer 140 may be disposed on the first semiconductor layer 110. The active layer 140 may be disposed between the second semiconductor layer 150 and the first semiconductor layer 110.

The active layer 140 may be formed of a semiconductor material. The active layer 140 may be formed in a single or multiple well structure using a compound semiconductor material of Group III-Group 5 elements. The active layer 140 may be formed of a nitride semiconductor. For example, the active layer 140 may include gallium nitride (GaN), indium gallium nitride (InGaN), indium gallium nitride (InAlGaN), or the like.

An active layer 140 that emits light when the blue light, for example, a compositional formula of _{In x Al y Ga 1 -x- y} N (0 = x = 1, 0 = y = 1, 0 = x + y = 1) well layer (142, 146) and having a _{in a Al b Ga 1 -a- b} N (0 = a = 1, 0 = b = 1, 0 = a + b = 1) a barrier layer (144 has a composition formula of It may have a single or multiple well structure having), but is not limited thereto. The well layers 142 and 146 may be formed of a material having a band gap smaller than the band gap of the barrier layer 144.

The active layer 140 may be formed by alternately stacking a plurality of well layers 142 and 146 and a barrier layer 144. The active layer 140 may include a plurality of well layers 142 and 146 to maximize light efficiency.

The well layers 142 and 146 may have a smaller energy band gap than the barrier layer 144. The well layers 142 and 146 may have a smaller energy band gap than the first semiconductor layer 110. The well layers 142 and 146 may have continuous energy levels of carriers.

The second semiconductor layer 150 may be formed on the active layer 140. The second semiconductor layer 150 may be implemented as a p-type semiconductor layer doped with a p-type dopant. When the light emitting element emitting light of a blue wavelength, a second semiconductor layer 150 is _{In x Al y Ga 1 -x- y} N (0 = x = 1, 0 = y = 1, 0 = x + y Semiconductor material having a composition formula of = 1), for example, selected from gallium nitride (GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), indium nitride (InN), InAlGaN, AlInN, and the like. P-type dopants such as magnesium (Mg), zinc (Zn), calcium (Ca), strontium (Sr), and barium (Ba) may be doped.

The first semiconductor layer 110, the active layer 140, and the second semiconductor layer 150 may be, for example, metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), or plasma. Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), etc. It is not limited.

The doping concentrations of the conductive dopants in the first semiconductor layer 110 and the second semiconductor layer 150 may be formed uniformly or non-uniformly, but are not limited thereto.

When the light emitting device 100 is a horizontal light emitting diode, the first electrode (not shown) may be disposed in one region of the first semiconductor layer 110. The first electrode (not shown) may be electrically connected to the first semiconductor layer 110. The first electrode (not shown) may transfer power connected from the outside to the first semiconductor layer 110.

When the light emitting device 100 is a horizontal light emitting diode, the second electrode (not shown) may be disposed in one region of the second semiconductor layer 150. When the light emitting device 100 is a vertical diode, the second electrode (not shown) may be formed of a semiconductor material, but the electrode arrangement of the light emitting device 100 is not limited.

The second electrode (not shown) may be electrically connected to the second semiconductor layer 150. The second electrode (not shown) may provide power to the second semiconductor layer 150 provided from the outside.

The first electrode (not shown) and the second electrode (not shown) may be conductive materials such as indium (In), cobalt (Co), silicon (Si), germanium (Ge), gold (Au), and palladium (Pd). ), Platinum (Pt), ruthenium (Ru), rhenium (Re), magnesium (Mg), zinc (Zn), hafnium (Hf), tantalum (Ta), rhodium (Rh), iridium (Ir), tungsten (W ), Titanium (Ti), silver (Ag), chromium (Cr), molybdenum (Mo), niobium (Nb), aluminum (Al), nickel (Ni), copper (Cu), and titanium tungsten alloy (WTi) It may be formed as a single layer or multiple layers using a metal or alloy selected from, but is not limited thereto.

The current injection layer 130 may be disposed between the first semiconductor layer 110 and the active layer 140. The current injection layer 130 may have a form in which a plurality of injection well layers 132 and 136 and a plurality of injection barrier layers 134 and 138 are alternately stacked. The current injection layer 130 may have a superlattice structure.

The energy band gaps of the injection well layers 132 and 136 may be smaller than the energy band gaps of the injection barrier layers 134 and 138. The injection well layers 132 and 136 may have an indium (In) content higher than the indium (In) content of the injection barrier layers 134 and 138.

The energy band gaps of the injection well layers 132 and 136 may be larger than the well layers 142 and 146 of the active layer 140 and smaller than the barrier layer 144 of the active layer 140.

The current injection layer 130 is formed so thin that the injection well layer and the injection barrier layer lose the quantum confinement effect, so that electrons or holes can spread throughout the current injection layer 130 by the quantum mechanical tunnel effect to form an energy band. Can be.

The current injection layer 130 includes an injection well layer in which the electrons or holes are spread throughout the current injection layer 130 and has an energy band gap lower than that of the first semiconductor layer 110. The recombination rate of electrons and holes can be increased.

The current spreading layer 120 may be disposed between the first semiconductor layer 110 and the current injection layer 130. The current spreading layer 120 may include a dispersion well layer 122 and a dispersion barrier layer 124. The current spreading layer 120 may have a structure in which the dispersion well layer 122 and the dispersion barrier layer 124 are stacked. The current spreading layer 120 may horizontally distribute the electrons supplied from the first semiconductor layer 110.

The thickness h1 of the dispersion well layer 122 may be 1.5 nm to 50 nm. When the thickness of the dispersion well layer 122 is 1.5 nm or less, it may be difficult to constrain electrons in quantum mechanics. When the thickness of the dispersion well layer 122 is 50 nm or more, the crystal quality of the light emitting device may be lowered to reduce light efficiency.

The dispersion barrier layer 124 may include aluminum indium gallium nitride (Al _x In _y GaN). The dispersion barrier layer 124 may have an aluminum content x of 0.05 to 0.25.

The dispersion barrier layer 124 may not function properly to trap electrons in the dispersion well layer 122 when the aluminum content x is 0.05 or less, and the energy band gap is too small, and the aluminum content x is 0.25 or more. Due to excessive energy band gap, electron injection efficiency of supplying electrons to the active layer 140 may be reduced.

The dispersion barrier layer 124 may have an indium content of y of 0.02 to 0.1. When the dispersion barrier layer 124 has an indium content of y of 0.02 or less, if the indium content is too small, the compressive stress increases with the increase of the aluminum content, and the mismatch between the first semiconductor layer 110 and the planar lattice constant increases. When the interlayer stress may be increased, and if the indium content of y is 0.1 or more, the function of trapping electrons in the dispersion well layer 122 may decrease as the energy bandgap decreases.

The dispersion well layer 122 may include indium gallium nitride (In _z GaN). Indium (In) content z of the dispersion well layer 122 may be 0.01 to 0.06. When the indium content z of the dispersion well layer 122 is less than or equal to 0.01, the energy band gap may be excessively small, so that the electron injection efficiency in which electrons are supplied to the active layer 140 may be reduced, and when z is 0.06 or more, the energy band As the gap becomes excessively large, it may be difficult to improve the horizontal distribution of electrons, and it may be difficult to supply electrons to the wider side of the active layer 140.

2 is a diagram illustrating an energy band gap of a light emitting device according to an embodiment.

Referring to FIG. 2, the dispersion well layer 122 may have a smaller energy band gap than the first semiconductor layer 110. The dispersion well layer 122 may have a smaller energy band gap than the dispersion barrier layer 124. The dispersion well layer 122 may have a higher content of indium (In) than the first semiconductor layer 110 or the dispersion barrier layer 124.

The dispersion barrier layer 124 may have a larger energy band gap than the dispersion well layer 122 and the first semiconductor layer 110. The dispersion barrier layer 124 may have a higher aluminum (Al) content than the first semiconductor layer 110 or the dispersion barrier layer 124.

In the light emitting device of the exemplary embodiment, the dispersion barrier layer 124 may be in contact with the injection well layer 132. The dispersion barrier layer 124 may allow the electrons supplied from the first semiconductor layer 110 to be confined to the dispersion well layer 122.

The dispersion well layer 122 may have an energy band gap smaller than that of the first semiconductor layer 110. In FIG. 2, the dispersion well layer 122 and the dispersion barrier layer 124 are illustrated as one, but are not limited thereto. The dispersion well layer 122 and the dispersion barrier layer 124 may be alternately stacked.

The dispersion well layer 122 may have a higher content of indium (In) than the first semiconductor layer 110 and the dispersion barrier layer 124. The dispersion well layer 122 may have an energy band gap greater than that of the injection well layers 132 and 136.

3 is a diagram illustrating an energy band gap of a light emitting device according to an embodiment.

Referring to FIG. 3, the current spreading layer 120 may further include a distributed intermediate layer 126 having an energy band gap between the energy band gap of the dispersion well layer 122 and the energy band gap of the dispersion barrier layer 124. Can be.

The distributed intermediate layer 126 may have the same energy band gap as the first semiconductor layer 110. The distributed intermediate layer 126 may be disposed at a portion in contact with the current injection layer 130 of the current dispersion layer 120. The dispersed intermediate layer 126 may relieve interlayer stress caused by a momentary large change in the energy band gap at the interface between the layers.

The dispersion intermediate layer 126 may be disposed to contact the injection well layer 132. The dispersion intermediate layer 126 may have an energy band gap between the energy band gap of the injection well layer 132 and the energy band gap of the dispersion barrier layer 124.

The injection well layer 132 may have a smaller energy band gap than the dispersion well layer 122. In the current injection layer 130, injection well layers 132 and 136 and injection barrier layers 134 and 138 may be alternately stacked.

The injection well layers 132 and 136 may have an energy band gap greater than that of the well layers 142 and 146 of the active layer 140. The injection barrier layers 134 and 138 may have an energy band gap greater than the barrier layer 144 of the active layer 140.

4 is a diagram illustrating an energy band gap of a light emitting device according to an embodiment.

Referring to FIG. 4, the dispersion intermediate layer 128 may be disposed between the dispersion well layer 122 and the dispersion barrier layer 124.

The dispersion intermediate layer 128 may smoothly change the energy band gap between the dispersion well layer 122 and the dispersion barrier layer 124. The dispersion intermediate layer 128 may relieve the interlayer stress between the dispersion well layer 122 and the dispersion barrier layer 124. The dispersion intermediate layer 128 may have an indium content between the dispersion well layer 122 and the dispersion barrier layer 124.

The dispersion intermediate layers 126 and 128 may be plural in number. The dispersion intermediate layer may be disposed between the dispersion well layer 122 and the dispersion barrier layer 124, and may be disposed between the dispersion barrier layer 124 and the injection well layer 132. Dispersion barrier layer 124 may be between the energy bandgap of each of the layers above and below the energy bandgap.

5 is a diagram illustrating an energy band gap of a light emitting device according to an embodiment.

Referring to FIG. 5, the dispersion intermediate layer 126 may be disposed between the dispersion barrier layer 124 and the current injection layer 130.

The dispersion intermediate layer 126 is a light emitting device that the energy band gap is smaller as the current injection layer 130 is closer. The dispersion intermediate layer 126 may be closer to the energy band gap of the injection well layer 132 as the energy band gap is closer to the current injection layer 130. As the dispersion intermediate layer 126 is closer to the current injection layer 130, the indium (In) content may be increased.

6 is a graph showing the content of aluminum and indium in the dispersion barrier layer of the light emitting device according to the embodiment.

Referring to FIG. 6, the dispersion barrier layer may include aluminum indium gallium nitride (Al _x In _y GaN). As the aluminum content of the barrier layer increases, the energy band gap of the barrier layer increases, and the lattice constant in the plane direction may decrease. As the indium content of the dispersion barrier layer increases, the energy band gap may decrease and the plane lattice constant may increase.

Optimization values that take into account the appropriate aluminum and indium content of the dispersion barrier layer are distributed in the triangle of the graph shown in FIG.

7A is a perspective view illustrating a light emitting device package 300 including a light emitting device of an embodiment, and FIG. 7B is a cross-sectional view illustrating a light emitting device package 300 including a light emitting device of an embodiment.

7A and 7B, the light emitting device package 300 according to the embodiment includes a body 310 having a cavity formed therein, and first and second electrodes 340 and 350 mounted on the body 310. The light emitting device 320 electrically connected to the two electrodes and the encapsulant 330 formed in the cavity may be included, and 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), photosensitive glass (PSG), polyamide 9T (PA9T) ), Neogeotactic polystyrene (SPS), a metal material, sapphire (Al ₂ O ₃ ), beryllium oxide (BeO), a printed circuit board (PCB, Printed Circuit Board) may be formed of at least one. 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 inclined surface. The angle of reflection of light emitted from the light emitting device 320 may vary according to the angle of the inclined surface, thereby adjusting the directivity angle of the light emitted to the outside.

The shape of the cavity formed in the body 310 as viewed from above may be circular, rectangular, polygonal, elliptical, or the like, and in particular, may have a curved shape, but 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. After the encapsulant 330 is filled in the cavity, the encapsulant 330 may be formed by UV or thermal curing.

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

The phosphor (not shown) included in the encapsulant 330 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, or a yellowish red light according to a wavelength of light emitted from the light emitting device 320. One of the phosphor, the orange luminescent phosphor, and the red luminescent phosphor can 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 device 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, and the blue light generated from the blue light emitting diode and As yellow light generated by excitation by blue light is mixed, the light emitting device package 300 may provide white light.

When the light emitting device 320 is a green light emitting diode, a magenta phosphor or a blue and red phosphor (not shown) is mixed. When the light emitting device 320 is a red light emitting diode, a cyan phosphor or a blue and green phosphor is mixed. 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 may 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.

In FIG. 7B, the light emitting device 320 is mounted on the first electrode 340, but is not limited thereto. The light emitting device 320, the first electrode 340, and the second electrode 350 may be wire bonded. May be electrically connected by any one of the following methods, a flip chip method, and a die bonding method.

The first electrode 340 and the second electrode 350 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. The first electrode 340 and the second electrode 350 may be formed to have a single layer or a multilayer structure, but is not limited thereto.

The light emitting device 320 may be mounted on the first electrode 340, and may be, for example, a light emitting device emitting light of red, green, blue, white, or UV (ultraviolet) light emitting device emitting ultraviolet light. However, the present invention is not limited thereto. One or more light emitting devices 320 may be mounted.

The light emitting device 320 may be applied to a horizontal type in which all of its electrical terminals are formed on the upper surface, or to a vertical type or flip chip formed on the upper and lower surfaces.

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

A plurality of light emitting device packages 300 according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, or the like, which is an optical member, may be disposed on an optical 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 indicator device, or 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 or a street lamp. .

8A is a perspective view illustrating a lighting system 400 including a light emitting device according to an embodiment, and FIG. 8B is a cross-sectional view illustrating a cross-sectional view taken along line D-D 'of the lighting system of FIG. 8A.

That is, FIG. 8B is a cross-sectional view of the illumination system 400 of FIG. 8A cut in the plane of the longitudinal direction Z and the height direction X, and viewed in the horizontal direction Y. FIG.

8A and 8B, the lighting system 400 may include a body 410, a cover 430 coupled to the body 410, and a closing cap 450 positioned at both ends of the body 410. have.

The lower surface of the body 410 is fastened to the light emitting device module 443, the body 410 is conductive and so that the heat generated from the light emitting device package 444 can be discharged to the outside through the upper surface of the body 410 The heat dissipation effect may be formed of an excellent metal material, but is not limited thereto.

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

The light emitting device package 444 may be mounted on the substrate 442 in multiple colors and in multiple rows to form a module. The light emitting device package 444 may be mounted at the same interval or may be mounted at various separation distances as necessary to adjust brightness. As the substrate 442, a metal core PCB (MCPCB) or a PCB made of FR4 may be used.

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

The cover 430 may protect the light emitting device module 443 from the foreign matters. The cover 430 may include diffusing particles to prevent glare of light generated from the light emitting device package 444 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 430. A prism pattern or the like may be formed on the surface. In addition, a phosphor may be applied to at least one of an inner surface and an outer surface of the cover 430.

Since the light generated from the light emitting device package 444 is emitted to the outside through the cover 430, the cover 430 should be excellent in light transmittance, and sufficient heat resistance to withstand the heat generated from the light emitting device package 444. The cover 430 is made of a material containing polyethylene terephthalate (PET), polycarbonate (PC), or polymethyl methacrylate (PMMA). Can be formed.

Closing cap 450 is located at both ends of the body 410 may be used for sealing the power supply (not shown). Power cap 452 is formed in the closing cap 450, the lighting system 400 according to the embodiment can be used immediately without a separate device to the terminal from which the existing fluorescent lamps are removed.

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

9 is an edge-light method, and 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.

The liquid crystal display panel 510 may display an image by using 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 interposed therebetween.

The color filter substrate 512 may implement colors of an image displayed through the liquid crystal display panel 510.

The thin film transistor substrate 514 is electrically connected to the printed circuit board 518 on which a plurality of circuit components are mounted through the 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 of a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 570 may convert the light provided from the light emitting device module 520, the light emitting device module 520 into a surface light source, and provide the light guide plate 530 to the liquid crystal display panel 510. Reflective sheet for reflecting the light emitted from the rear of the light guide plate 530 and the plurality of films 550, 560, 564 to uniform the luminance distribution of the light provided from the 530 and improve the vertical incidence ( 540.

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

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

The backlight unit 570 is 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 condensing the diffused light to improve vertical incidence. It may be configured, and may include a protective film 564 for protecting the prism film 550.

10 is an exploded perspective view of a liquid crystal display including the light emitting device according to the embodiment. However, the parts shown and described in FIG. 9 will not be described in detail repeatedly.

10 is a direct view liquid crystal display 600 according to an embodiment. The liquid crystal display 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. 9, a detailed description thereof will be omitted.

The backlight unit 670 may include a plurality of light emitting device modules 623, a reflective sheet 624, a lower chassis 630 in which the light emitting device modules 623 and the reflective sheet 624 are accommodated, and an upper portion of the light emitting device module 623. It may include a diffusion plate 640 and a plurality of optical film 660 disposed in the.

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

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

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

Light generated by the light emitting device 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 includes a diffusion film 666, a prism film 650, and a protective film 664.

The light emitting device according to the embodiment may not be limitedly applied to the configuration and method of the embodiments described as described above, but the embodiments may be selectively combined with all or some of the embodiments so that various modifications may be made. It may be configured.

Although the preferred embodiments have been illustrated and described above, the invention is not limited to the specific embodiments described above, and does not depart from the gist of the invention as claimed in the claims. Various modifications can be made by the person having the above, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

110: first semiconductor layer 120: current distribution layer
130: current injection layer 140: active layer
150: second semiconductor layer
300: light emitting device package.

Claims

A first semiconductor layer;
A current injection layer disposed on the first semiconductor layer and including a plurality of injection well layers having an energy band gap smaller than that of the first semiconductor layer;
An active layer disposed on the current injection layer;
A second semiconductor layer disposed on the active layer; And
A dispersion well layer disposed between the first semiconductor layer and the current injection layer and having an energy band gap smaller than an energy band gap of the first semiconductor layer and an energy band gap larger than an energy band gap of the first semiconductor layer. And a current dispersing layer including a dispersion barrier layer.
The current spreading layer further includes a distributed intermediate layer having an energy band gap between an energy band gap of the dispersion well layer and an energy band gap of the dispersion barrier layer.
The dispersion intermediate layer is disposed between the dispersion well layer and the dispersion barrier layer or between the dispersion barrier layer and the current injection layer.
The scattering intermediate layer is a light emitting device that the energy band gap is smaller as the current injection layer closer.

The method of claim 1,
The current spreading layer is alternately stacked with the dispersion well layer and the dispersion barrier layer,
The dispersion well layer has a higher indium (In) content than the first semiconductor layer.

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The method of claim 1,
The dispersion well layer has an energy band gap smaller than that of the first semiconductor layer.
The dispersion well layer has an energy band gap greater than that of the injection well layer,
The dispersion barrier layer has a larger energy band gap than the first semiconductor layer.

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The method of claim 1,
The dispersion barrier layer includes aluminum indium gallium nitride (Al _x In _y GaN),
The dispersion barrier layer has an aluminum content x of 0.05 to 0.25,
The dispersion barrier layer has an indium content of y of 0.02 to 0.1.

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The method of claim 1,
The dispersion well layer includes indium gallium nitride (In _z GaN),
Indium content z of the dispersion well layer is 0.01 to 0.06,
The thickness of the dispersion well layer is 1.5nm to 50nm,
The dispersion well layer and the dispersion barrier layer is a plurality of light emitting devices are alternately stacked.

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