KR20140006626A - Light emitting device - Google Patents

Abstract

The embodiment of the present invention relates to a light emitting device, a manufacturing method thereof, a light emitting device package, and a lighting system. The light emitting device according to the embodiment of the present invention includes: a first conductive semiconductor layer (112); an active layer (114) which is formed on the first conductive semiconductor layer (112); a second conductive semiconductor layer (116) which is formed on the active layer (114); a first electrode (131) which is formed on the second conductive semiconductor layer (116); and a reflection layer which is formed on the first electrode (131).

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.

Light Emitting Device is a pn junction diode whose electrical energy is converted into light energy. It can be produced from compound semiconductor such as group III and group V on the periodic table and by controlling the composition ratio of compound semiconductor, It is possible.

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 band gap energy of the conduction band and the valance band. Is mainly emitted in the form of heat or light, and when emitted in the form of light, becomes a light emitting element.

For example, nitride semiconductors have received great interest in the development of optical devices and high power electronic devices due to their high thermal stability and wide bandgap energy. In particular, blue light emitting devices, green light emitting devices, and ultraviolet light emitting devices using nitride semiconductors are commercially used and widely used.

The nitride semiconductor light emitting device may be classified into a lateral type light emitting device and a vertical type light emitting device depending on the position of the electrode layer.

A horizontal type light emitting device is formed such that a nitride semiconductor layer is formed on a sapphire substrate and two electrode layers are disposed on the upper side of the nitride semiconductor layer.

For example, according to the related art, in a horizontal type light emitting device, a transparent ohmic layer is formed on a p-type semiconductor layer, and a portion of the p-type semiconductor layer and the active layer are removed to expose the n-type semiconductor layer.

Then, a p-type electrode is formed on the transparent ohmic layer, and an n-type electrode is formed on the exposed n-type semiconductor layer.

According to the prior art, the p-type electrode and the n-type electrode occupy a considerable area of the upper region of the light emitting device chip, and also, in the prior art, each p-type electrode, in order to improve current efficiency by preventing current concentration and promoting current diffusion, A branch electrode is formed for the n-type electrode to increase the light efficiency through improving the current injection efficiency. When the branch electrodes are formed in this way, the area occupied by the electrodes increases more.

Meanwhile, according to the related art, a molding material is formed on a light emitting device chip, and a phosphor is provided for wavelength conversion.

However, according to the prior art, there is a problem in that the amount of light is lost due to light absorption by the electrode after the light extracted light is converted and scattered in the phosphor (scattering).

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 improving brightness.

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 conductivity type semiconductor layer 116 on the active layer 114; A first electrode 131 on the second conductive semiconductor layer 116; And a reflective layer on the first electrode 131.

According to the light emitting device, the method of manufacturing the light emitting device, the light emitting device package, and the lighting system according to the embodiment, the light intensity can be improved by providing a reflective layer having a high reflectance on the electrode in order to minimize the light loss absorbed by the electrode.

1 is a plan view of a light emitting device according to an embodiment;
2 is a first cross-sectional view of a light emitting device according to the first embodiment;
3 is a second cross-sectional view of the light emitting device according to the first embodiment;
4 is a view illustrating reflectance according to a wavelength in a light emitting device according to an embodiment;
5A is a sectional view of a light emitting device according to a second embodiment;
5B is an enlarged view of a portion of a multiple thin film mirror reflection layer in the light emitting device according to the second embodiment;
6 is a cross-sectional view of a light emitting device according to a third embodiment;
7 is a sectional view of a light emitting device package according to an embodiment.
8 to 10 are views showing the lighting apparatus according to the embodiment.
11 and 12 are views showing another example of the lighting apparatus according to the embodiment.
13 is a perspective view of a backlight unit 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. In addition, the size of each component does not necessarily reflect the actual size.

(Example)

1 is a plan view of a light emitting device 100 according to the embodiment, FIG. 2 is a first cross-sectional view taken along the line II ′ of the light emitting device according to the first embodiment, and FIG. 3 is a light emission according to the first embodiment. 2nd sectional drawing along the II-II 'line | wire of an element.

1 to 6 illustrate an example in which the light emitting device according to the embodiment is a horizontal light emitting device, but the embodiment is not limited thereto.

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, and a second conductive type on the active layer 114. The semiconductor layer 116 includes a first electrode 131 on the second conductive semiconductor layer 116 and a reflective layer on the first electrode 131. As described below, the reflective layer may include, but is not limited to, a first reflective layer 141 of the first embodiment, a first reflective layer 142 of the second embodiment, and a second reflective layer 152.

The first conductive semiconductor layer 112 and the active layer 114 and the second conductive semiconductor layer 116 may form a light emitting structure 110, And may be formed on a predetermined substrate 105.

The substrate 105 may be formed of a material having excellent thermal conductivity, or may be 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 May be used.

Embodiments include a buffer layer (not shown) and / or an undoped semiconductor layer (not shown) on the substrate 105 to mitigate lattice mismatch between the material of the light emitting structure 110 and the substrate 105 And the material of the buffer layer may be at least one of Group III-V compound semiconductor such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN, but is not limited thereto.

In an exemplary embodiment, the first conductive semiconductor layer 112 may be formed of a semiconductor compound. It may be implemented as a compound semiconductor, such as Group 3-5, Group 2-6, and the first conductivity type dopant may be doped. When the first conductive semiconductor layer 112 is an N-type semiconductor layer, the first conductive dopant may include Si, Ge, Sn, Se, and Te as an N-type dopant.

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, .

In an embodiment, the active layer 114 may be formed of at least one of a single quantum well structure, a multi quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure. have. For example, the active layer 114 may be formed with a multiple quantum well structure by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

The well layer / barrier layer of the active layer 114 is formed of one or more pair structures of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, GaAs (InGaAs) / AlGaAs, GaP (InGaP) / AlGaP. But it is not limited thereto. The well layer may be formed of a material having a lower band gap than the band gap of the barrier layer.

In an embodiment, a current diffusion layer (not shown), for example, an undoped GaN layer may be formed on the first conductive semiconductor layer 112.

In addition, the embodiment can efficiently inject electrons by forming an electron injection layer (not shown), for example, a first conductivity type gallium nitride layer on the current diffusion layer.

In addition, the embodiment is a strain control layer (not shown) on the electron injection layer, for example, In _y Al _x Ga _(1-xy) N (0≤x≤1, 0≤y≤1) / GaN, etc. The strain control layer formed may be formed to effectively alleviate stresses that are odd due to lattice mismatch between the first conductivity-type semiconductor layer 112 and the active layer 114.

An active layer 114 may be formed on the strain control layer.

In an embodiment, an electron blocking layer (not shown) is formed on the active layer 114 to improve the luminous efficiency by acting as electron blocking and cladding of the active layer. For example, the electron blocking layer may be formed of an Al _x In _y Ga _(1-xy) N (0? _{X ? 1, 0? Y ? 1} ) semiconductor, And may be formed to a thickness of about 100 A to about 600 A, but the present invention is not limited thereto.

The electron blocking layer may be formed of a superlattice of Al _z Ga _(1-z) N / GaN (0? _Z ? 1), but is not limited thereto.

The electron blocking layer can efficiently block the electrons that are ion-implanted into the p-type and overflow, and increase the hole injection efficiency. For example, the electron blocking layer can effectively prevent electrons that are overflowed by ion implantation of Mg in a concentration range of about 10 ¹⁸ to 10 ²⁰ / cm ³ , and increase the hole injection efficiency.

The second conductivity type semiconductor layer 116 may be formed on the electron blocking layer. The second conductivity type semiconductor layer 116 may be formed of a semiconductor compound. It may be implemented as a compound semiconductor, such as Group 3-5, Group 2-6, and the second conductivity type dopant may be doped.

For example, the second conductive semiconductor layer 116 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. When the second conductive semiconductor layer 116 is a p-type semiconductor layer, the second conductive dopant may be a p-type dopant and may include Mg, Zn, Ca, Sr, and Ba.

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, but is not limited thereto. In addition, a semiconductor, for example, an n-type semiconductor layer (not shown) having a polarity opposite to that of the second conductive type may be formed on the second conductive type semiconductor layer 116. Accordingly, the light emitting structure 110 may be implemented as 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.

In an embodiment, the transmissive electrode 120 is formed on the second conductive semiconductor layer 116, and the translucent electrode 140 may include a transmissive ohmic layer, and a single metal may be used to efficiently inject a carrier. Alternatively, metal alloys, metal oxides, and the like may be formed by stacking multiple layers. For example, the translucent electrode 140 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), or IGTO. (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), It may be formed including at least one of ZnO, IrOx, RuOx, NiO, but is not limited to these materials.

According to an embodiment, a portion of the transparent electrode 120, the second conductive semiconductor layer 116, and the active layer 114 is removed so that the first conductive semiconductor layer 112 is exposed. A first electrode 131 is formed, and a second electrode 132 is formed on the exposed first conductive semiconductor layer 112.

Meanwhile, the embodiment forms a molding material (not shown) on the light emitting device chip, and the molding material includes a phosphor (not shown) for wavelength conversion.

However, according to the prior art, there is a problem in that the amount of light is lost due to light absorption by the electrode after the light extracted light is converted and scattered in the phosphor (scattering).

Accordingly, the embodiment may include a reflective layer on the first electrode 131 disposed on the second conductivity-type semiconductor layer 116.

For example, as illustrated in FIG. 3, the first electrode 131 is connected to the first pad electrode 131p and the first pad electrode 131p on the second conductivity-type semiconductor layer 116. The first branch electrode 131r may be disposed on the conductive semiconductor layer.

In this case, the reflective layer includes a first reflective layer 141 disposed on the first branch electrode 131r, and the first reflective layer 141 is disposed above and to the side of the first branch electrode 131r. The first branch reflective layer 141b may be included.

In addition, the reflective layer may include a first pad reflective layer 141a disposed to expose the first pad region P1 on the upper side of the first pad electrode 131p.

4 is a view illustrating reflectance according to a wavelength in the light emitting device according to the embodiment.

In the prior art, Au is disposed on the upper side of the pad electrode, and the reflectance of Au rapidly decreases to 40% or less at a reflectance of 500 nm or less. As a result, light loss occurs due to light absorption at the pad electrode of the prior art. there is a problem.

Accordingly, the embodiment may include a first reflective layer 141 on the first pad electrode 131p and the first branch electrode 131r, and the material of the first reflective layer 141 may be formed in a blue wavelength region. It may include a reflective metal having a reflectance of 70% or more. For example, the first reflective layer 141 may include any one or more of Al, Ag, or an alloy thereof.

In an embodiment, when the material of the first reflective layer 141 or the second reflective layer 152 employs Al, the thickness may be about 50 nm to 200 nm, and when Ag is used, the thickness may be about 250 nm to 600 nm. As a result, it is possible to secure process margin in consideration of chip size and maintain optimal reflectance.

Therefore, according to the embodiment, the light intensity may be improved by providing a reflective layer having a high reflectance on the electrode in order to minimize the light loss absorbed by the electrode.

In addition, in the embodiment, as shown in FIG. 2, a part of the first conductivity-type semiconductor layer 112 is exposed, and the second electrode 132 and the second electrode disposed on the exposed first conductivity-type semiconductor layer 112 are formed. It may further include a second reflective layer 152 disposed on the second electrode 132.

In this case, the second reflective layer 152 may include a second branch reflective layer 152b disposed on the top and side surfaces of the second branch electrode (not shown).

In addition, the second reflective layer 152 may include a second pad reflective layer 152a disposed to expose the second pad region P2 on the upper side of the second pad electrode 132p.

5A is a cross-sectional view of the light emitting device 102 according to the second embodiment, and FIG. 5B is a partially enlarged view of the multiple thin film mirror reflection layer 142 in the light emitting device 102 according to the second embodiment.

The second embodiment can employ the technical features of the first embodiment.

In the second embodiment, the reflective layer 142 may include multiple thin film mirrors.

For example, the multiple thin film mirror, which is the reflective layer 142 of the second embodiment, is formed on the first multi thin film mirror 142a and the first branch electrode 131r disposed on the first pad electrode 131p. It may include two multiple thin film mirror 142b.

For example, the first multi-film mirror 142a is repeatedly stacked at least once with a first thin film layer 142a1 having a first refractive index and a second thin film layer 142a2 having a second refractive index different from the first refractive index. Can be formed. For example, the first thin film layer 142a1 and the second thin film layer 142a2 may be repeatedly formed at least four times, but are not limited thereto.

The material of the first thin film layer 142a1 may be any one of SiO ₂ , TiO ₂ , MgF, and Si _x N _y , and the material of the second thin film layer 142a2 may be SiO ₂ , TiO ₂ , MgF, Si _x. N _y It may have one of the other material, but is not limited thereto. The material described above may be formed by a deposition method or the like, but is not limited thereto.

In addition, when the refractive index difference between the first thin film layer 142a1 and the second thin film layer 142a2 is one or more, the first thin film layer 142a1 and the second thin film layer 142a2 may be repeatedly formed at least four times. .

6 is a cross-sectional view of the light emitting element 103 according to the third embodiment.

The third embodiment can employ the technical features of the first and second embodiments.

In the third exemplary embodiment, the reflective layer includes the multiple thin film mirrors 142 and the reflective metal layer 141 to maximize the reflectance in the electrode region to minimize the light absorbed by the electrode.

For example, the multiple thin film mirror 142 is disposed on the first pad electrode 131p and the second multiple thin film mirror 142b disposed on the first branch electrode 131r. It may include. In addition, the reflective layer includes a first reflective layer 141 disposed on the first branch electrode 131r, and the first reflective layer 141 is disposed above and to the side of the first branch electrode 131r. The first branch reflective layer 141b may be included. In addition, the first reflective layer 141 may include a first pad reflective layer 141a disposed to expose the first pad region P1 on the upper side of the first pad electrode 131p.

According to the light emitting device, the method of manufacturing the light emitting device, the light emitting device package, and the lighting system according to the embodiment, the light intensity can be improved by providing a reflective layer having a high reflectance on the electrode in order to minimize the light loss absorbed by the electrode.

7 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 include a silicon material, a synthetic resin material, or a metal material, and an 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 light emitting device of the horizontal type illustrated in FIGS. 1 to 6, but is not limited thereto. A vertical light emitting device and a flip chip light emitting device may also be applied.

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.

8 to 10 are views showing a lighting apparatus according to an embodiment.

FIG. 8 is a perspective view of the illumination device according to the embodiment viewed from above, FIG. 9 is a perspective view of the illumination device shown in FIG. 8, and FIG. 10 is an exploded perspective view of the illumination device shown in FIG.

8 to 10, 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, . ≪ / RTI > 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 a light emitting device or a light emitting device package according to the embodiment.

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 is reflected on the inner surface of the cover 2100 to reflect the light returned to the light source module 2200 side again toward the cover 2100. 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 2511 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 to provide 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 part 2670 is inserted into the connection part 2750 of the inner case 2700 and receives an electrical signal from the outside. 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.

11 and 12 are views showing another example of the lighting apparatus according to the embodiment.

FIG. 11 is a perspective view of a lighting apparatus according to the embodiment, and FIG. 12 is an exploded perspective view of the lighting apparatus shown in FIG.

11 and 12, the lighting apparatus according to the embodiment includes a cover 3100, a light source portion 3200, a heat sink 3300, a circuit portion 3400, an inner case 3500, and a socket 3600 . 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 the cover 3100 is coupled with the heat discharging body 3300 by the rotation of the cover 3100 in such a manner that the thread of the cover 3100 is engaged with the thread groove of the heat discharging body 3300 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.

In Figure 12, the light source 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 . ≪ / RTI > In addition, it is possible to use a Chips On Board (COB) type that can directly bond the LED chip unpacked on the printed circuit board. 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 side surfaces, or the light source unit 3200 may be disposed on some of the six side surfaces. In FIG. 15, the light source unit 3200 is disposed on three side surfaces of the six side surfaces.

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. Therefore, the substrate 3210 and the top surface 310 of the heat sink 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 lighter than metals and have the advantage of having 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 unit 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 an accommodating part 510 for accommodating the circuit part 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 600 may be coupled to the inner case 500. 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 screw thread structure of the connection part 3550.

13 is an exploded perspective view 1200 of a backlight unit according to an embodiment. However, the backlight unit 1200 of Fig. 13 is an example of the illumination system, and is not limited thereto.

The backlight unit 1200 according to the embodiment includes a light guide plate 1210, a light emitting module unit 1240 that provides light to the light guide plate 1210, a reflective member 1220 under the light guide plate 1210, and the light guide plate. 1210, a bottom cover 1230 for accommodating the light emitting module unit 1240 and the reflective member 1220, but 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. ≪ / RTI >

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

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.

According to the light emitting device, the manufacturing method of the light emitting device, the light emitting device package and the lighting system according to the embodiment, the brightness can be improved.

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 may be combined or modified with respect to other embodiments by those 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, the second conductive semiconductor layer 116,
The first electrode 131, the first pad electrode 131p, and the first branch electrode 131r.
The first reflective layer 141, the first pad reflective layer 141a, the first branch reflective layer 141b,
Multiple Thin Film Mirrors (142)

Claims (11)

A first conductive semiconductor layer;
An active layer on the first conductive semiconductor layer;
A second conductive semiconductor layer on the active layer;
A first electrode on the second conductive semiconductor layer; And
Light emitting device comprising a; reflective layer on the first electrode. The method according to claim 1,
The first electrode is
A first pad electrode on the second conductive semiconductor layer; And
And a first branch electrode connected to the first pad electrode and disposed on the second conductive semiconductor layer. The method of claim 2,
The reflective layer,
A first reflective layer disposed on the first branch electrode,
The first reflective layer,
A light emitting device comprising a first branch reflective layer disposed on the upper side and the side of the first branch electrode. The method of claim 3,
The reflective layer,
And a first pad reflecting layer disposed to expose a first pad area above the first pad electrode. The method according to claim 1,
A portion of the first conductivity type semiconductor layer is exposed,
A second electrode disposed on the exposed first conductive semiconductor layer; And
The light emitting device further comprises a second reflective layer disposed on the second electrode. 6. The method of claim 5,
The second reflective layer,
A light emitting device comprising a second branch reflective layer disposed on the upper side and the side of the second branch electrode. The method of claim 6,
The second reflective layer,
And a second pad reflecting layer disposed to expose a second pad region above the second pad electrode. The method according to any one of claims 1 to 7,
The reflective layer
A light emitting device comprising a reflective metal having a reflectance of 70% or more in a blue wavelength region. The method of claim 8,
The reflective metal is
Light emitting device comprising at least one of Al, Ag or Al and Ag alloy. The method according to any one of claims 1 to 7,
The reflective layer
Light emitting device comprising multiple thin film mirrors. The method according to any one of claims 1 to 7,
The reflective layer
Light emitting device comprising multiple thin film mirrors and reflective metal.

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