KR20140074524A

KR20140074524A - Light emitting device

Info

Publication number: KR20140074524A
Application number: KR1020120142564A
Authority: KR
Inventors: 봉하종
Original assignee: 엘지이노텍 주식회사
Priority date: 2012-12-10
Filing date: 2012-12-10
Publication date: 2014-06-18

Abstract

Embodiments relate to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.
The light emitting device according to the embodiment includes a first conductive semiconductor layer 112; An active layer 114 on the first conductive semiconductor layer 112; A second conductive type In _x Ga ₁ _- _x N layer (0 <x <1) (126) on the active layer 114; A second conductive type gallium nitride based layer 128 on the second conductive type In _x Ga ₁ _- _x N layer 126; And a second conductive type semiconductor layer 116 on the second conductive type gallium nitride based layer 128.

Description

[0001] LIGHT EMITTING DEVICE [0002]

Embodiments relate to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system.

A light emitting device is a diode in which electric energy is converted into light energy, and a light emitting device can realize various colors by controlling a composition ratio of a compound semiconductor.

When the 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 band gap energy of the conduction band and the valance band in the form of light .

BACKGROUND ART Light emitting devices using nitride semiconductors have been used in the fields of optical devices and high output electronic devices due to their high thermal stability and wide band gap energy. For example, a blue light emitting element, a green light emitting element, and an ultraviolet (UV) light emitting element using a nitride semiconductor are commercially available and widely used.

On the other hand, as the demand for a high efficiency light emitting device has recently increased, the improvement of the light intensity of the light emitting device has become an issue.

There have been attempts to improve the structure of the active layer (MQW), the improvement of the electron blocking layer (EBL), and the improvement of the lower layer of the active layer.

For example, according to the related art, there is a problem that electrons are rapidly recombined with holes in the active layer through the multiple quantum well structure because electrons have a larger mobility than holes. Hence, An electron blocking layer (EBL) of the AlGaN series is used to confine electrons in the multiple quantum well structure.

However, the electron blocking layer of the AlGaN series has a relatively large energy band gap, and the interfacial characteristics are poor due to the difference in lattice constant between the AlGaN-based electron blocking layer and the active layer. And the forward voltage is increased and the luminous efficiency is lowered.

In order to solve the problems associated with the introduction of the AlGaN-based electron blocking layer, the prior art further disposes a p-type InAlGaN-based layer between the active layer and the AlGaN-based electron blocking layer to form an interface between the active layer and the AlGaN- There are studies to improve the characteristics.

2 is an example of an energy band diagram when a p-type InAlGaN-based layer is additionally disposed between an active layer and an AlGaN-based electron blocking layer in the prior art.

However, as shown in FIG. 2, a hole barrier (B) for a hole, which is a carrier, is formed at the interface between the active layer and the AlGaN-based electron blocking layer. So that the hole injection efficiency is lowered.

As a result, according to the prior art, an attempt to improve the interfacial property generates hole barriers, resulting in lowering of hole injection efficiency, resulting in a reduction in luminous efficiency of the light emitting device.

Thus, according to the prior art, there is no adequate solution to enhance the carrier injection efficiency while improving the interfacial characteristics.

Embodiments provide a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system capable of increasing light emitting efficiency by improving carrier injection efficiency while improving interfacial characteristics.

The light emitting device according to the embodiment includes a first conductive semiconductor layer 112; An active layer 114 on the first conductive semiconductor layer 112; A second conductive type In _x Ga ₁ _- _x N layer (0 <x <1) (126) on the active layer 114; A second conductive type gallium nitride based layer 128 on the second conductive type In _x Ga ₁ _- _x N layer 126; And a second conductive type semiconductor layer 116 on the second conductive type gallium nitride based layer 128.

Embodiments can provide a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system capable of improving light emitting efficiency by improving interfacial characteristics and increasing carrier injection efficiency.

1 is a cross-sectional view of a light emitting device according to an embodiment.
2 is an exemplary view of an energy band diagram of a conventional light emitting device.
3 is an exemplary view of an energy band diagram of a light emitting device according to an embodiment.
4 is a cross-sectional view of a light emitting device package according to an embodiment.
Figures 5 to 7 show a lighting device according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), area, pattern or structure may be referred to as being "on" or "under" the substrate, each layer Quot; on "and" under "are intended to include both" directly "or" indirectly " do. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

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 of each component does not entirely reflect the actual size.

(Example)

1 is a cross-sectional view of a light emitting device 100 according to a first embodiment.

The light emitting device 100 according to the embodiment includes a first conductive semiconductor layer 112, an active layer 114 on the first conductive semiconductor layer 112, A second conductivity type gallium nitride series layer 128 (128) is formed on the second conductivity type In _x Ga ₁ _- _x N layer 126, and an In _x Ga ₁ _- _x N layer (where 0 <x < And a second conductive type semiconductor layer 116 on the second conductive type gallium nitride based layer 128.

The substrate 105 may be formed of a material having excellent thermal conductivity, and may include a conductive substrate or an insulating substrate. For example, the substrate 105 is a sapphire (Al ₂ O _3), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ Or the like.

Embodiments can increase light extraction efficiency by providing a light reflection pattern. For example, a patterned sapphire substrate (PSS) may be formed on the substrate 105 to improve light extraction efficiency.

According to the embodiment, the buffer layer 107 and the undoped semiconductor layer 108 are provided on the substrate 105 to mitigate the lattice mismatch between the material of the light emitting structure 110 and the substrate 105 have. At this time, the material of the buffer layer 107 may include at least one of Group III-V compound semiconductors such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN and AlInN.

Next, a first conductive type semiconductor layer 112 is formed on the undoped semiconductor layer 108. For example, the first conductive semiconductor layer 112 may have a composition formula of In _x Al _y Ga ₁ _-x- _y N (0? X? 1, 0? _Y? 1, 0? _X + And the like. For example, the first conductive semiconductor layer 112 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, But is not limited thereto.

According to the embodiment, the gallium nitride-based superlattice layer 124 may be formed on the first conductivity type semiconductor layer 112. The gallium nitride-based superlattice layer 124 can effectively alleviate a stress caused by lattice mismatch between the first conductivity type semiconductor layer 112 and the active layer 114.

The active layer 114 may include at least one of a single quantum well structure, a multi quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure.

The active layer 114 may include a well layer 114w and a quantum barrier 114b structure and the structure of the well layer 114w and the quantum barrier 114b may include InGaN / GaN, InGaN / InGaN, GaN / AlGaN, But not limited to, any one or more pairs of InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP (InGaP) / AlGaP. The well layer may be formed of a material having a band gap lower than the band gap of the barrier layer.

On the other hand, as described above, according to the prior art, when a p-type InAlGaN-based layer is additionally disposed between the active layer and the AlGaN-based electron blocking layer,

The conventional art has improved the interface characteristics between the active layer and the AlGaN-based electron blocking layer. However, as shown in FIG. 2, a hole barrier (B) for a hole as a carrier is formed, Resulting in a side effect that reduces the efficiency.

As a result, according to the prior art, an attempt to improve the interfacial characteristics causes the hole barrier (B) to occur, resulting in a problem in lowering the hole injection efficiency, resulting in a decrease in luminous efficiency of the light emitting device.

For this, the light emitting device according to the embodiment may include a second conductive In _x Ga _1-x N layer (where 0 <x <1) 126 on the active layer 114.

The second conductive type In _x Ga ₁ _- _x N layer a second conductivity type GaN-based layer 128 is formed on the (126) is formed, the second conductive type GaN-based layer 128 is Al _y In _z Ga ₁ _{- (y + z)} N layers (where 0 <y <1, 0 <z <1). The second conductivity type gallium nitride based layer 128 serves as electron blocking and cladding of the active layer to improve the luminous efficiency.

In addition, the second conductivity type gallium nitride based layer 128 may be formed of a superlattice of Al _z Ga _(1-z) N / GaN (0? _Z ? 1), but is not limited thereto.

The second conductivity type gallium nitride based layer 128 can effectively block electrons that are ion-implanted into the p-type and overflow, and increase the hole injection efficiency. For example, the second conductivity type gallium nitride based layer 128 may be doped with Mg to a concentration in the range of about 10 ¹⁸ to 10 ¹⁹ / cm ³ to effectively block the electrons that overflow and increase the hole injection efficiency .

Hereinafter, the second conductive type In _x Ga ₁ _- _x N layer 126, which is one of the main features of the present invention, will be described in more detail.

3 is an exemplary view of an energy band diagram of a light emitting device according to an embodiment.

The present invention is characterized in that a strain generated between the last quantum barrier layer of the active layer and the second conductivity type gallium nitride series layer 128 is inserted into the second conductivity type In _x Ga ₁ _- _x N layer 126, Since strain is relaxed and the characteristics of the interface are improved and the hole barrier height is lowered by the insertion of the second conductive In _x Ga _1-x N layer 126, ) Injection efficiency is improved and the internal quantum efficiency (IQE) can be improved.

For example, the second conductivity type In _x Ga ₁ _- _x N layer 126 of the embodiment relaxes the difference in the composition of the quantum barrier of the active layer and the composition of the second conductivity type gallium nitride series layer 128, By reducing the difference, it is possible to alleviate the strain at the interface and at the same time improve the characteristics of the interface.

In addition, according to the embodiment, the strain at the interface between the second conductivity type In _x Ga ₁ _- _x N layer 126 and the second conductivity type gallium nitride series layer 128 is relaxed, and as the interface characteristics are improved, The hole barrier height is lowered and hole injection efficiency can be improved.

In addition, according to the embodiment, the In concentration of the second conductive type In _x Ga ₁ _- _x N layer 126 is higher than the In concentration of the second conductive type gallium nitride based layer 128, -Type In _x Ga ₁ _- _x N layer 126, the hole height can be lowered and the hole injection efficiency can be improved.

According to an embodiment of the present invention, the second conductivity type gallium nitride based layer 128 is a second conductive type Al _y In _z Ga _{1- (y + z)} N layer (0 <y <1, 0 <z < 1), and the doping concentration of the second conductive type element of the second conductive type In _x Ga ₁ _- _x N layer (126) is greater than the doping concentration of the second conductive type Al _y In _z Ga ₁ _{- (y + z)} N Is higher than the doping concentration of the second conductive type element in the layer 126, it is possible to increase the hole injection efficiency into the active layer. For example, the second conductivity type gallium nitride based layer 128 may be implanted with Mg in a concentration range of about 10 ¹⁸ to 10 ¹⁹ / cm ³ , and the second conductivity type In _x Ga ₁ _- _x N layer (126) may be doped with Mg in a concentration range of about 5 x 10 < ¹⁶ > to 10 ²⁰ / cm < ³ >

In addition, the thickness of the second conductivity type In _x Ga ₁ _- _x N layer 126 may be smaller than the thickness of the second conductivity type gallium nitride layer 128 in the embodiment.

Embodiment hole (Hole) injection features of the second conductivity type In _x Ga ₁ to _- _x N layer 126 and formed to be thinner than the second conductivity type GaN-based layer 128, the remaining p-GaN region An undoped gallium nitride layer 127 can be formed to function as a hole transfer rather than a hole source.

The undoped gallium nitride layer 127 may be thicker than the second conductive In _x Ga ₁ _- _x N layer 126.

Accordingly, the undoped gallium nitride layer 127, which is the remaining p-GaN region, is undoped GaN, so that the mobility of holes can be remarkably increased.

According to the embodiment, the hole injection efficiency is maintained or improved, and the crystal quality is improved, so that the overall luminous efficiency can be increased.

The embodiment has solved the problem that it is difficult to increase the doping concentration of the p-type element in the process of forming the second conductivity type gallium nitride based layer 128 or the second conductivity type semiconductor layer 116.

For example, as the composition ratio of Al in the second conductive type gallium nitride based layer 128 is higher, the binding energy of AlN is larger and doping becomes more difficult. In addition, the hole injection efficiency is increased in the second conductive type semiconductor layer 116 There is a problem that the crystal quality is lowered when the Mg doping is performed at a high concentration to raise the luminous efficiency.

Therefore, in the embodiment, the second conductivity type In _x Ga ₁ _- _x N layer 126 having a relatively high doping concentration is formed on the active layer 114, and the second conductivity type semiconductor layer 116, The gallium nitride based layer 126 and the undoped gallium nitride layer 127 are organically arranged so as to function as a hole transporting layer so that the second conductivity type In _x Ga ₁ _- _x N layer 126 having a relatively high doping concentration Rich holes can be provided in the active layer 114. Hole injection efficiency can be maintained or improved and crystal quality can be improved and the operating voltage of the light emitting device can be reduced to increase the overall luminous efficiency.

Referring again to FIG. 1, a second conductivity type semiconductor layer 116 is formed on the second conductivity type gallium nitride based layer 128.

The second conductive semiconductor layer 116 may be formed of a semiconductor compound. For example, the second conductive semiconductor layer 116 may be formed of a compound semiconductor such as a Group III-V, a Group II-VI, or the like, and may be doped with a second conductive dopant.

The second conductivity type semiconductor layer 116 may be a semiconductor having a composition formula of In _x Al _y Ga ₁ _-x- _y N (0? X? 1, 0? _Y? 1, 0? _X + &Lt; / RTI > When the second conductive semiconductor layer 116 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as p-type dopants.

Next, a light-transmitting electrode 130 is formed on the second conductive semiconductor layer 116, and the light-transmitting electrode 130 may include a light-transmitting ohmic layer. The light-transmitting electrode 130 may be formed by laminating a single metal, a metal alloy, a metal oxide, or the like so as to efficiently perform carrier injection.

The transmissive electrode 130 may be formed of one of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide ZnO, ZnO, IrOx, ZnO, AlGaO, AZO, ATO, GZO, IZO, RuOx, and NiO, and is not limited to such a material.

In an embodiment, the first conductive semiconductor layer 112 may be an n-type semiconductor layer, and the second conductive semiconductor layer 116 may be a p-type semiconductor layer. Also, on the second conductive semiconductor layer 116, a semiconductor (e.g., an n-type semiconductor) (not shown) having a polarity opposite to that of the second conductive type may be formed. Accordingly, the light emitting structure 110 may have any one of an n-p junction structure, a p-n junction structure, an n-p-n junction structure, and a p-n-p junction structure.

Next, the light-transmitting electrode 130, the second conductivity type semiconductor layer 116, the second conductivity type gallium nitride series layer 128, and the undoped gallium nitride layer (not shown) are formed to expose the first conductivity type semiconductor layer 112 127, the second conductive In _x Ga ₁ _- _x N layer 126, the active layer 114, and the gallium nitride superlattice layer 124 can be removed.

Next, a second electrode 132 is formed on the transparent electrode 130, and a first electrode 131 is formed on the exposed first conductive semiconductor layer 112.

4 is a view illustrating a light emitting device package 200 having a light emitting device according to embodiments.

The light emitting device package 200 according to the embodiment includes a package body 205, a third electrode layer 213 and a fourth electrode layer 214 provided on the package body 205, a package body 205, And a molding member 230 surrounding the light emitting device 100. The light emitting device 100 is electrically connected to the third electrode layer 213 and the fourth electrode layer 214,

The package body 205 may be formed of a silicon material, a synthetic resin material, or a metal material, and the inclined surface may be formed around the light emitting device 100.

The third electrode layer 213 and the fourth electrode layer 214 are electrically isolated from each other and provide power to the light emitting device 100. The third electrode layer 213 and the fourth electrode layer 214 may function to increase light efficiency by reflecting the light generated from the light emitting device 100, And may serve to discharge heat to the outside.

The light emitting device 100 may be a horizontal type light emitting device as illustrated in FIG. 1, but is not limited thereto. Vertical light emitting devices and flip chip light emitting devices may also be used.

The light emitting device 100 may be mounted on the package body 205 or on the third electrode layer 213 or the fourth electrode layer 214.

The light emitting device 100 may be electrically connected to the third electrode layer 213 and / or the fourth electrode layer 214 by a wire, flip chip, or die bonding method. The light emitting device 100 is electrically connected to the third electrode layer 213 through the wire 230 and is electrically connected to the fourth electrode layer 214 directly.

The molding member 230 surrounds the light emitting device 100 to protect the light emitting device 100. In addition, the molding member 230 may include a phosphor 232 to change the wavelength of light emitted from the light emitting device 100.

A light guide plate, a prism sheet, a diffusion sheet, a fluorescent sheet, and the like, which are optical members, may be disposed on a path of light emitted from the light emitting device package. The light emitting device package, the substrate, and the optical member may function as a backlight unit or function as a lighting unit. For example, the lighting system may include a backlight unit, a lighting unit, a pointing device, a lamp, and a streetlight.

5 to 7 are exploded perspective views illustrating embodiments of an illumination system having a light emitting device according to an embodiment.

5, the lighting apparatus according to the embodiment includes a cover 2100, a light source module 2200, a heat discharger 2400, a power supply unit 2600, an inner case 2700, a socket 2800, . Further, the illumination device according to the embodiment may further include at least one of the member 2300 and the holder 2500. The light source module 2200 may include the light emitting device 100 or the light emitting device package 200 according to the present invention.

For example, the cover 2100 may have a shape of a bulb or a hemisphere, and may be provided in a shape in which the hollow is hollow and a part is opened. The cover 2100 may be optically coupled to the light source module 2200. For example, the cover 2100 may diffuse, scatter, or excite light provided from the light source module 2200. The cover 2100 may be a kind of optical member. The cover 2100 may be coupled to the heat discharging body 2400. The cover 2100 may have an engaging portion that engages with the heat discharging body 2400.

The inner surface of the cover 2100 may be coated with a milky white paint. Milky white paints may contain a diffusing agent to diffuse light. The surface roughness of the inner surface of the cover 2100 may be larger than the surface roughness of the outer surface of the cover 2100. This is for sufficiently diffusing and diffusing the light from the light source module 2200 and emitting it to the outside.

The cover 2100 may be made of glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance and strength. The cover 2100 may be transparent so that the light source module 2200 is visible from the outside, and may be opaque. The cover 2100 may be formed by blow molding.

The light source module 2200 may be disposed on one side of the heat discharging body 2400. Accordingly, heat from the light source module 2200 is conducted to the heat discharger 2400. The light source module 2200 may include a light source unit 2210, a connection plate 2230, and a connector 2250.

The member 2300 is disposed on the upper surface of the heat discharging body 2400 and has guide grooves 2310 through which the plurality of light source portions 2210 and the connector 2250 are inserted. The guide groove 2310 corresponds to the substrate of the light source unit 2210 and the connector 2250.

The surface of the member 2300 may be coated or coated with a light reflecting material. For example, the surface of the member 2300 may be coated or coated with a white paint. The member 2300 reflects the light reflected by the inner surface of the cover 2100 toward the cover 2100 in the direction toward the light source module 2200. Therefore, the light efficiency of the illumination device according to the embodiment can be improved.

The member 2300 may be made of an insulating material, for example. The connection plate 2230 of the light source module 2200 may include an electrically conductive material. Therefore, electrical contact can be made between the heat discharging body 2400 and the connecting plate 2230. The member 2300 may be formed of an insulating material to prevent an electrical short circuit between the connection plate 2230 and the heat discharging body 2400. The heat discharger 2400 receives heat from the light source module 2200 and heat from the power supply unit 2600 to dissipate heat.

The holder 2500 blocks the receiving groove 2719 of the insulating portion 2710 of the inner case 2700. Therefore, the power supply unit 2600 housed in the insulating portion 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510. The guide protrusion 2510 has a hole through which the protrusion 2610 of the power supply unit 2600 passes.

The power supply unit 2600 processes or converts an electrical signal provided from the outside and provides the electrical signal to the light source module 2200. The power supply unit 2600 is housed in the receiving groove 2719 of the inner case 2700 and is sealed inside the inner case 2700 by the holder 2500.

The power supply unit 2600 may include a protrusion 2610, a guide 2630, a base 2650, and an extension 2670.

The guide portion 2630 has a shape protruding outward from one side of the base 2650. The guide portion 2630 may be inserted into the holder 2500. A plurality of components may be disposed on one side of the base 2650. The plurality of components include, for example, a DC converter for converting AC power supplied from an external power source into DC power, a driving chip for controlling driving of the light source module 2200, an ESD (ElectroStatic discharge) protective device, and the like, but the present invention is not limited thereto.

The extension portion 2670 has a shape protruding outward from the other side of the base 2650. The extension portion 2670 is inserted into the connection portion 2750 of the inner case 2700 and receives an external electrical signal. For example, the extension portion 2670 may be provided to be equal to or smaller than the width of the connection portion 2750 of the inner case 2700. One end of each of the positive wire and the negative wire is electrically connected to the extension portion 2670 and the other end of the positive wire and the negative wire are electrically connected to the socket 2800 .

The inner case 2700 may include a molding part together with the power supply part 2600. The molding part is a hardened portion of the molding liquid so that the power supply unit 2600 can be fixed inside the inner case 2700.

6, the lighting apparatus according to the present invention includes a cover 3100, a light source unit 3200, a heat sink 3300, a circuit unit 3400, an inner case 3500, and a socket 3600. As shown in FIG. can do. The light source unit 3200 may include a light emitting device or a light emitting device package according to the embodiment.

The cover 3100 has a bulb shape and is hollow. The cover 3100 has an opening 3110. The light source unit 3200 and the member 3350 can be inserted through the opening 3110. [

The cover 3100 may be coupled to the heat discharging body 3300 and surround the light source unit 3200 and the member 3350. The light source part 3200 and the member 3350 may be shielded from the outside by the combination of the cover 3100 and the heat discharging body 3300. The coupling between the cover 3100 and the heat discharging body 3300 may be combined through an adhesive, or may be combined by various methods such as a rotational coupling method and a hook coupling method. The rotation coupling method is a method in which a screw thread of the cover 3100 is engaged with a thread groove of the heat dissipating body 3300 so that the cover 3100 is coupled to the heat dissipating body 3300 by rotation of the cover 3100 In the hook coupling method, the protrusion of the cover 3100 is inserted into the groove of the heat discharging body 3300, and the cover 3100 and the heat discharging body 3300 are coupled.

The cover 3100 is optically coupled to the light source unit 3200. Specifically, the cover 3100 may diffuse, scatter, or excite light from the light emitting device 3230 of the light source unit 3200. The cover 3100 may be a kind of optical member. Here, the cover 3100 may have a phosphor inside / outside or in the inside thereof to excite light from the light source part 3200.

The inner surface of the cover 3100 may be coated with a milky white paint. Here, the milky white paint may include a diffusing agent for diffusing light. The surface roughness of the inner surface of the cover 3100 may be larger than the surface roughness of the outer surface of the cover 3100. This is for sufficiently scattering and diffusing light from the light source part 3200.

The cover 3100 may be made of glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance and strength. The cover 3100 may be a transparent material that can be seen from the outside of the light source unit 3200 and the member 3350, and may be an invisible and opaque material. The cover 3100 may be formed, for example, by blow molding.

The light source unit 3200 is disposed on the member 3350 of the heat sink 3300 and may be disposed in a plurality of units. Specifically, the light source portion 3200 may be disposed on at least one of the plurality of side surfaces of the member 3350. The light source unit 3200 may be disposed at the upper end of the member 3350.

The light source portion 3200 may be disposed on three of the six sides of the member 3350. However, the present invention is not limited thereto, and the light source portion 3200 may be disposed on all the sides of the member 3350. The light source unit 3200 may include a substrate 3210 and a light emitting device 3230. The light emitting device 3230 may be disposed on one side of the substrate 3210.

The substrate 3210 has a rectangular plate shape, but is not limited thereto and may have various shapes. For example, the substrate 3210 may have a circular or polygonal plate shape. The substrate 3210 may be a printed circuit pattern on an insulator. For example, the substrate 3210 may be a printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB . &Lt; / RTI > In addition, a COB (Chips On Board) type that can directly bond an unpackaged LED chip on a printed circuit board can be used. In addition, the substrate 3210 may be formed of a material that efficiently reflects light, or may be formed of a color whose surface efficiently reflects light, for example, white, silver, or the like. The substrate 3210 may be electrically connected to the circuit unit 3400 housed in the heat discharging body 3300. The substrate 3210 and the circuit portion 3400 may be connected, for example, via a wire. The wire may pass through the heat discharging body 3300 to connect the substrate 3210 and the circuit unit 3400.

The light emitting device 3230 may be a light emitting diode chip that emits red, green, or blue light, or a light emitting diode chip that emits UV light. Here, the light emitting diode chip may be a lateral type or a vertical type, and the light emitting diode chip may emit blue, red, yellow, or green light. .

The light emitting device 3230 may have a phosphor. The phosphor may be at least one of a garnet system (YAG, TAG), a silicate system, a nitride system, and an oxynitride system. Alternatively, the fluorescent material may be at least one of a yellow fluorescent material, a green fluorescent material, and a red fluorescent material.

The heat discharging body 3300 may be coupled to the cover 3100 to dissipate heat from the light source unit 3200. The heat discharging body 3300 has a predetermined volume and includes an upper surface 3310 and a side surface 3330. A member 3350 may be disposed on the upper surface 3310 of the heat discharging body 3300. An upper surface 3310 of the heat discharging body 3300 can be engaged with the cover 3100. The upper surface 3310 of the heat discharging body 3300 may have a shape corresponding to the opening 3110 of the cover 3100.

A plurality of radiating fins 3370 may be disposed on the side surface 3330 of the heat discharging body 3300. The radiating fin 3370 may extend outward from the side surface 3330 of the heat discharging body 3300 or may be connected to the side surface 3330. The heat dissipation fin 3370 may increase the heat dissipation area of the heat dissipator 3300 to improve heat dissipation efficiency. Here, the side surface 3330 may not include the radiating fin 3370.

The member 3350 may be disposed on the upper surface 3310 of the heat discharging body 3300. The member 3350 may be integral with the top surface 3310 or may be coupled to the top surface 3310. The member 3350 may be a polygonal column. Specifically, the member 3350 may be a hexagonal column. The hexagonal column member 3350 has an upper surface, a lower surface, and six sides. Here, the member 3350 may be a circular column or an elliptic column as well as a polygonal column. When the member 3350 is a circular column or an elliptic column, the substrate 3210 of the light source portion 3200 may be a flexible substrate.

The light source unit 3200 may be disposed on six sides of the member 3350. The light source unit 3200 may be disposed on all six sides and the light source unit 3200 may be disposed on some of the six sides. In FIG. 6, the light source unit 3200 is disposed on three sides of six sides.

The substrate 3210 is disposed on a side surface of the member 3350. The side surface of the member 3350 may be substantially perpendicular to the upper surface 3310 of the heat discharging body 3300. Accordingly, the upper surface 3310 of the substrate 3210 and the heat discharging body 3300 may be substantially perpendicular to each other.

The material of the member 3350 may be a material having thermal conductivity. This is to receive the heat generated from the light source 3200 quickly. The material of the member 3350 may be, for example, aluminum (Al), nickel (Ni), copper (Cu), magnesium (Mg), silver (Ag), tin (Sn) Or the member 3350 may be formed of a thermally conductive plastic having thermal conductivity. Thermally conductive plastics are advantageous in that they are lighter in weight than metals and have unidirectional thermal conductivity.

The circuit unit 3400 receives power from the outside and converts the supplied power to the light source unit 3200. The circuit unit 3400 supplies the converted power to the light source unit 3200. The circuit unit 3400 may be disposed on the heat discharging body 3300. Specifically, the circuit unit 3400 may be housed in the inner case 3500 and stored in the heat discharging body 3300 together with the inner case 3500. The circuit portion 3400 may include a circuit board 3410 and a plurality of components 3430 mounted on the circuit board 3410.

The circuit board 3410 has a circular plate shape, but is not limited thereto and may have various shapes. For example, the circuit board 3410 may be in the shape of an oval or polygonal plate. Such a circuit board 3410 may be one in which a circuit pattern is printed on an insulator.

The circuit board 3410 is electrically connected to the substrate 3210 of the light source unit 3200. The electrical connection between the circuit board 3410 and the substrate 3210 may be connected by wire, for example. The wires may be disposed inside the heat discharging body 3300 to connect the circuit board 3410 and the substrate 3210.

The plurality of components 3430 include, for example, a DC converter for converting AC power supplied from an external power source to DC power, a driving chip for controlling the driving of the light source 3200, An electrostatic discharge (ESD) protection device, and the like.

The inner case 3500 houses the circuit portion 3400 therein. The inner case 3500 may have a receiving portion 3510 for receiving the circuit portion 3400.

The receiving portion 3510 may have a cylindrical shape as an example. The shape of the accommodating portion 3510 may vary depending on the shape of the heat discharging body 3300. The inner case 3500 may be housed in the heat discharging body 3300. The receiving portion 3510 of the inner case 3500 may be received in a receiving portion formed on the lower surface of the heat discharging body 3300.

The inner case 3500 may be coupled to the socket 3600. The inner case 3500 may have a connection portion 3530 that engages with the socket 3600. The connection portion 3530 may have a threaded structure corresponding to the thread groove structure of the socket 3600. The inner case 3500 is nonconductive. Therefore, electrical short circuit between the circuit portion 3400 and the heat discharging body 3300 is prevented. For example, the inner case 3500 may be formed of plastic or resin.

The socket 3600 may be coupled to the inner case 3500. Specifically, the socket 3600 may be engaged with the connection portion 3530 of the inner case 3500. The socket 3600 may have the same structure as a conventional incandescent bulb. The circuit portion 3400 and the socket 3600 are electrically connected. The electrical connection between the circuit part 3400 and the socket 3600 may be connected via a wire. Accordingly, when external power is applied to the socket 3600, the external power may be transmitted to the circuit unit 3400. The socket 3600 may have a screw groove structure corresponding to the threaded structure of the connection portion 3550.

7, the backlight unit according to the present invention includes a light guide plate 1210, a light emitting module 1240 for providing light to the light guide plate 1210, a light guide plate 1210, A bottom cover 1230 for housing the light guide plate 1210, the light emitting module unit 1240 and the reflection member 1220 may be included in the lower portion of the bottom cover 1220. However, the present invention is not limited thereto.

The light guide plate 1210 serves to diffuse light into a surface light source. The light guide plate 1210 may be made of a transparent material such as acrylic resin such as PMMA (polymethyl methacrylate), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphthalate Resin. &Lt; / RTI >

The light emitting module 1240 provides light to at least one side of the light guide plate 1210 and ultimately acts as a light source of a display device in which the backlight unit is disposed.

The light emitting module 1240 may be in contact with the light guide plate 1210, but is not limited thereto. Specifically, the light emitting module 1240 includes a substrate 1242 and a plurality of light emitting device packages 200 mounted on the substrate 1242. The substrate 1242 is mounted on the light guide plate 1210, But is not limited to.

The substrate 1242 may be a printed circuit board (PCB) including a circuit pattern (not shown). However, the substrate 1242 may include not only a general PCB, but also a metal core PCB (MCPCB), a flexible PCB (FPCB), and the like.

The plurality of light emitting device packages 200 may be mounted on the substrate 1242 such that a light emitting surface on which the light is emitted is spaced apart from the light guiding plate 1210 by a predetermined distance.

The reflective member 1220 may be formed under the light guide plate 1210. The reflection member 1220 reflects the light incident on the lower surface of the light guide plate 1210 so as to face upward, thereby improving the brightness of the backlight unit. The reflective member 1220 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto.

The bottom cover 1230 may receive the light guide plate 1210, the light emitting module 1240, and the reflective member 1220. For this purpose, the bottom cover 1230 may be formed in a box shape having an opened upper surface, but the present invention is not limited thereto.

The bottom cover 1230 may be formed of a metal material or a resin material, and may be manufactured using a process such as press molding or extrusion molding.

Embodiments can provide a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and an illumination system that can improve light emitting efficiency by improving interfacial characteristics and increasing carrier injection efficiency.

The features, structures, effects and the like described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Accordingly, the contents of such combinations and modifications should be construed as being included in the scope of the embodiments.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. It can be seen that the modification and application of branches are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that the present invention may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.

The first conductive semiconductor layer 112, the active layer 114,
A second conductive type In _x Ga ₁ _- _x N layer 126,
The undoped gallium nitride layer 127,
A second conductivity type gallium nitride based layer 128,
The second conductivity type semiconductor layer 116,

Claims

A first conductive semiconductor layer;
An active layer on the first conductive semiconductor layer;
A second conductive type In _x Ga ₁ _- _x N layer (where 0 < x <1);
A second conductive type gallium nitride based layer on the second conductive type In _x Ga ₁ _- _x N layer; And
And a second conductivity type semiconductor layer on the second conductivity type gallium nitride based layer.

The method according to claim 1,
Wherein the second conductivity type gallium nitride based layer comprises an Al _y In _z Ga ₁ _{- (y + z)} N layer (where 0 <y <1, 0 <z <
And the concentration of In in the second conductivity type In _x Ga ₁ _- _x N layer is higher than the concentration of In in the second conductivity type gallium nitride series layer.

The method according to claim 1,
Wherein the second conductivity type gallium nitride based layer comprises a second conductivity type Al _y In _z Ga ₁ _{- (y + z)} N layer (where 0 <y <1, 0 <z <
The second conductive type In _x Ga ₁ _- a second doping concentration of the conductive element of the _x N layer has the second conductivity type _{Al y In z Ga 1 - (} y + z) a second doping of the conductive element of the N layer Lt; / RTI >

The method according to claim 1,
The thickness of the second conductive type In _x Ga ₁ _- _x N layer is
And the second conductive type gallium nitride based layer is thinner than the second conductive type gallium nitride based layer.

5. The method according to any one of claims 1 to 4,
And an undoped gallium nitride layer between the second conductive type In _x Ga ₁ _- _x N layer and the second conductive type gallium nitride based layer.

6. The method of claim 5,
The undoped gallium nitride layer
And the second conductive type In _x Ga ₁ _- _x N layer is thicker than the second conductive type In _x Ga ₁ _- _x N layer.