KR20210135444A - Light emitting device - Google Patents

Abstract

An objective of the present invention is to provide a light emitting device driven at high current and having excellent thermal reliability and mechanical reliability. The light emitting device comprises: a light emitting structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer; first and second contact electrodes located on the light emitting structure and electrically connected to the first and second conductive semiconductor layers, respectively; an insulation material to insulate the first and second contact electrodes from each other; a connection electrode located on the second contact electrode; a stress buffer layer located on the insulation material; and first and second bulk electrodes located on the light emitting structure and the stress buffer layer and electrically connected to the first and second contact electrodes, respectively. The connection electrode is located between the second bulk electrode and the second contact electrode. The stress buffer layer is located between the insulation material and the bulk electrodes and includes a rough surface.

Description

Light emitting device {LIGHT EMITTING DEVICE}

The present invention relates to a light emitting device, and more particularly, to a light emitting device having improved mechanical stability.

Recently, as the demand for a small high-power light emitting device increases, the demand for a large-area flip-chip type light emitting device having excellent heat dissipation efficiency is increasing. The electrode of the flip chip light emitting device is directly bonded to the secondary substrate, and since a wire for supplying external power to the flip chip light emitting device is not used, heat dissipation efficiency is very high compared to that of the horizontal light emitting device. Therefore, even when a high-density current is applied, heat can be effectively conducted to the secondary substrate side, and thus the flip-chip type light emitting device is suitable as a high output light emitting source.

In addition, for miniaturization and high output of the light emitting device, a process of packaging the light emitting device in a separate housing is omitted and the demand for a chip scale package using the light emitting device itself as a package is increasing. In particular, since the electrode of the flip-chip type light emitting device can function similarly to the lead of the package, the flip chip type light emitting device can be usefully applied also in such a chip scale package.

When such a chip-scale package type device is used as a high-power light emitting device, a high-density current is applied to the chip-scale package. When a high-density current is applied, the heat generated from the light emitting chip increases accordingly. Such heat generates thermal stress in the light emitting device, and generates a stress generated at an interface between materials having different coefficients of thermal expansion and a residual stress resulting therefrom. Therefore, a light emitting device applied to a high power light emitting device requires high heat dissipation efficiency and excellent mechanical stability.

An object of the present invention is to provide a light emitting device that is driven at a high current and has excellent thermal and mechanical reliability.

A light emitting device according to an aspect of the present invention is a light emitting structure including a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer positioned between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer. ; first and second contact electrodes positioned on the light emitting structure and in ohmic contact with the first and second conductivity-type semiconductor layers, respectively; an insulating layer insulating the first and second contact electrodes and partially covering the first and second contact electrodes; a connection electrode positioned on the second contact electrode; a stress buffer layer positioned on the insulating layer; first and second bulk electrodes disposed on the light emitting structure and the stress buffer layer and electrically connected to the first and second contact electrodes, respectively; and an insulating support covering side surfaces of the first and second bulk electrodes and at least partially exposing upper surfaces of the first and second bulk electrodes, wherein the connection electrode is formed between the second bulk electrode and the second bulk electrode. It is positioned between the second contact electrodes, and the stress buffer layer is positioned between the insulating layer and the bulk electrodes.

The stress buffer layer may be in contact with the first bulk electrode, the second bulk electrode, and the insulating support.

The stress buffer layer may include a photosensitive material.

In addition, the stress buffer layer may include at least one of polyimide, Teflon, benzocyclobutyne (BCB), and parylene.

Furthermore, the insulating support may include an epoxy molding compound (EMC).

In some embodiments, the stress buffer layer may have a roughened surface.

At least one of the first and second bulk electrodes may include a roughened surface formed on the side surface and/or an oxide film formed on the side surface.

The insulating layer may include a first insulating layer and a second insulating layer, wherein the first insulating layer partially covers the second contact electrode and partially covers the first conductivity-type semiconductor layer and the second contact electrode, respectively. may include a first opening and a second opening exposed to A third opening and a fourth opening partially exposing the first contact electrode and the second contact electrode may be included.

In addition, the stress buffer layer may be located on the second insulating layer.

The first bulk electrode may be electrically connected to the first contact electrode through the third opening, and the second bulk electrode may be electrically connected to the second contact electrode through the fourth opening.

The connection electrode may be formed of the same material as the first contact electrode.

A portion of the first insulating layer may be interposed between the first contact electrode and the second contact electrode.

The insulating layer may include a first opening and a second opening exposing the first contact electrode and the connection electrode, respectively.

The light emitting structure may include a region in which the first conductivity-type semiconductor layer is partially exposed, and the first contact electrode may be located in a region in which the first conductivity-type semiconductor layer is partially exposed.

The light emitting structure may include a plurality of holes partially exposing the first conductivity type semiconductor layer, and the first contact electrode may be electrically connected to the first conductivity type semiconductor layer through the plurality of holes. .

A light emitting device according to another aspect of the present invention includes a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer positioned between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer. structure; first and second contact electrodes positioned on the light emitting structure and in ohmic contact with the first and second conductivity-type semiconductor layers, respectively; an insulating layer insulating the first and second contact electrodes and partially covering the first and second contact electrodes; a connection electrode positioned on the second contact electrode; a stress buffer layer positioned on the insulating layer; first and second bulk electrodes disposed on the light emitting structure and the stress buffer layer and electrically connected to the first and second contact electrodes, respectively; and an insulating support covering side surfaces of the first and second bulk electrodes and at least partially exposing upper surfaces of the first and second bulk electrodes, wherein the connection electrode is formed between the second bulk electrode and the second bulk electrode. The residual stress of the stress buffer layer positioned between the second contact electrodes and generated by the predetermined stress is lower than the residual stress of the insulating layer.

The adhesiveness between the stress buffer layer and the insulating support may be higher than that between the insulating layer and the insulating support.

The insulating support may include EMC, and the insulating layer may include silicon oxide and/or silicon nitride.

The hygroscopicity of the stress buffer layer may be lower than that of the insulating support.

According to the present invention, there is provided a light emitting device including a stress buffer layer positioned between the light emitting structure and the insulating support. The stress buffer layer relieves stress applied to other components of the light emitting device to prevent cracks, etc., and to prevent moisture permeation. In addition, it is possible to improve the mechanical stability of the light emitting device by improving the adhesion between the stress buffer layer and the insulating support. Accordingly, a light emitting device having improved thermal reliability and mechanical reliability is provided.

1A and 1B are a plan view and a cross-sectional view illustrating a light emitting device according to an embodiment of the present invention.
2A and 2B are a plan view and a cross-sectional view illustrating a light emitting device according to another embodiment of the present invention.
3A and 3B are a plan view and a cross-sectional view illustrating a light emitting device according to another embodiment of the present invention.
4A and 4B are a plan view and a cross-sectional view illustrating a light emitting device according to another embodiment of the present invention.
5 is an exploded perspective view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a lighting device.
6 is an exploded perspective view and a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a display device.
7 is an exploded perspective view and a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a display device.
8 is a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a head lamp.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art to which the present invention pertains. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. And, in the drawings, the width, length, thickness, etc. of the components may be exaggerated for convenience. In addition, when one component is described as being “on” or “on” another component, each component is different from each component, as well as when each component is “immediately above” or “directly on” the other component. It includes the case where another component is interposed between them. Like reference numerals refer to like elements throughout.

1A and 1B are cross-sectional and plan views illustrating a light emitting device according to an embodiment of the present invention. FIG. 1B shows a cross-section of a portion corresponding to the line A-A' of FIG. 1A.

1A and 1B , the light emitting device 100 includes a light emitting structure 120 , a first contact electrode 130 , a second contact electrode 140 , insulating layers 150 and 160 , and a stress buffer layer 170 . , first and second bulk electrodes 181 and 183 and an insulating support 190 . Furthermore, the light emitting device 100 may further include a growth substrate (not shown) and a connection electrode 145 .

The light emitting structure 120 includes a first conductivity type semiconductor layer 121 , an active layer 123 located on the first conductivity type semiconductor layer 121 , and a second conductivity type semiconductor layer ( 125). The first conductivity type semiconductor layer 121 , the active layer 123 , and the second conductivity type semiconductor layer 125 may include a III-V series compound semiconductor, for example, (Al, Ga, In)N and The same nitride-based semiconductor may be included. The first conductivity-type semiconductor layer 121 may include an n-type impurity (eg, Si), and the second conductivity-type semiconductor layer 125 may include a p-type impurity (eg, Mg). have. Also, vice versa. The active layer 123 may include a multiple quantum well structure (MQW), and a composition ratio thereof may be determined to emit light having a desired peak wavelength.

Also, the light emitting structure 120 may include a region in which the second conductivity type semiconductor layer 125 and the active layer 123 are partially removed and the first conductivity type semiconductor layer 121 is partially exposed. For example, as shown in FIG. 1B , the light emitting structure 120 penetrates the second conductivity type semiconductor layer 125 and the active layer 123 to expose the first conductivity type semiconductor layer 121 . It may include a hole 120a. The hole 120a may be formed in plurality, and the shape and arrangement of the hole 120a are not limited to the illustrated ones. In addition, in the region where the first conductivity-type semiconductor layer 121 is partially exposed, the second conductivity-type semiconductor layer 125 and the active layer 125 and the active layer ( 123) may be provided.

In addition, the light emitting structure 120 may further include a roughened surface 120R formed by increasing the roughness of the lower surface thereof. The roughened surface 120R may be formed by using at least one method of wet etching, dry etching, and electrochemical etching, for example, an etching method using PEC etching or an etching solution containing KOH and NaOH, etc. It can be formed using Accordingly, the light emitting structure 120 may include protrusions and/or concave portions in a μm to nm scale formed on the surface of the first conductivity type semiconductor layer 121 . Light extraction efficiency of light emitted from the light emitting structure 120 may be improved by the roughened surface 120R.

In addition, the light emitting structure 120 may further include a growth substrate (not shown) positioned under the first conductivity type semiconductor layer 121 . The growth substrate is not limited as long as it is a substrate capable of growing the light emitting structure 120 . For example, the growth substrate may be a sapphire substrate, a silicon carbide substrate, a silicon substrate, a gallium nitride substrate, an aluminum nitride substrate, or the like. The growth substrate may be separated and removed from the light emitting structure 120 using a known technique.

The second contact electrode 140 is positioned on the second conductivity-type semiconductor layer 125 and may be in ohmic contact with the second conductivity-type semiconductor layer 125 . In addition, the second contact electrode 140 may at least partially cover the upper surface of the second conductivity-type semiconductor layer 125 , and further, may be disposed to entirely cover the upper surface of the second conductivity-type semiconductor layer 125 . have. In addition, the light emitting structure 120 may be formed to cover the upper surface of the second conductivity type semiconductor layer 125 as a single body in the remaining regions except for the position where the exposed region of the first conductivity type semiconductor layer 121 is formed. Accordingly, current may be uniformly supplied to the entire light emitting structure 120 , and current dispersion efficiency may be improved. However, the present invention is not limited thereto, and the second contact electrode 140 may include a plurality of unit electrodes.

The second contact electrode 140 may be formed of a material capable of ohmic contact with the second conductivity type semiconductor layer 125 , and may include, for example, a metallic material and/or a conductive oxide.

When the second contact electrode 140 includes a metallic material, the second contact electrode 140 may include a reflective layer and a cover layer covering the reflective layer. As described above, the second contact electrode 140 may be in ohmic contact with the second conductivity-type semiconductor layer 125 and may function to reflect light. Accordingly, the reflective layer may include a metal capable of forming an ohmic contact with the second conductivity-type semiconductor layer 125 while having high reflectivity. For example, the reflective layer may include at least one of Ni, Pt, Pd, Rh, W, Ti, Al, Mg, Ag, and Au. In addition, the reflective layer may include a single layer or multiple layers.

The cover layer may prevent mutual diffusion between the reflective layer and other materials, and may prevent other materials from diffusing into the reflective layer from damaging the reflective layer. Accordingly, the cover layer may be formed to cover a lower surface and a side surface of the reflective layer. The cover layer may be electrically connected to the second conductivity-type semiconductor layer 125 together with the reflective layer, thereby serving as an electrode together with the reflective layer. The cover layer may include, for example, Au, Ni, Ti, Cr, or the like, and may include a single layer or multiple layers.

The reflective layer and the cover layer may be formed using electron beam deposition, plating, or the like.

Meanwhile, when the second contact electrode 140 includes a conductive oxide, the conductive oxide may be ITO, ZnO, AZO, IZO, or the like. When the second contact electrode 140 includes the conductive oxide, it may cover the upper surface of the second conductive type semiconductor layer 125 having a larger area than when the second contact electrode 140 includes a metal. That is, the separation distance from the edge of the region where the first conductivity-type semiconductor layer 121 is exposed to the second contact electrode 140 may be relatively shorter when the second contact electrode 140 is formed of a conductive oxide. have. In this case, the shortest distance from the portion where the second contact electrode 140 and the second conductivity type semiconductor layer 125 contact to the portion where the first contact electrode 130 and the first conductivity type semiconductor layer 121 contact Since can be relatively shorter, the forward voltage (V _f ) of the light emitting device 100 can be reduced.

This may be due to a difference in manufacturing method between a case in which the second contact electrode 140 is formed of a metallic material and a case in which the second contact electrode 140 is formed of a conductive oxide. For example, since the metallic material is formed by deposition or plating, it is formed in a portion spaced apart from the outer edge of the second conductivity-type semiconductor layer 125 by a predetermined distance by the process margin of the mask. On the other hand, after the conductive oxide is entirely formed on the second conductivity-type semiconductor layer 125 , the conductive oxide is removed in the same process in the etching process for exposing the first conductivity-type semiconductor layer 121 . Accordingly, the conductive oxide may be formed relatively closer to the outer edge of the second conductivity-type semiconductor layer 125 . However, the present invention is not limited thereto.

In addition, when the second contact electrode 140 includes ITO, the first insulating layer 150 includes SiO ₂ , and the first contact electrode 130 includes Ag, ITO/SiO ₂ /Ag stack An omnidirectional reflector comprising the structure may be formed.

The insulating layers 150 and 160 partially cover the first and second contact electrodes 130 and 140 , and the first and second contact electrodes 130 and 140 are connected to each other. Insulate. The insulating layers 150 and 160 may include a first insulating layer 150 and a second insulating layer 160 . Hereinafter, the first insulating layer 150 will be described first, and the contents related to the second insulating layer 160 will be described later.

The first insulating layer 150 may partially cover the upper surface of the light emitting structure 120 and the second contact electrode 140 . In addition, the first insulating layer 150 may cover the side surface of the hole 120a and partially expose the first conductivity type semiconductor layer 121 exposed to the hole 120a. The first insulating layer 150 may include an opening positioned in a portion corresponding to the hole 120a and an opening exposing a portion of the second contact electrode 140 . The first conductivity-type semiconductor layer 121 and the second contact electrode 140 may be partially exposed through the openings.

The first insulating layer 150 may include an insulating material, for example, SiO ₂ , SiN _x , MgF _{2 ,} or the like. Furthermore, the first insulating layer 150 may include multiple layers, and may include a distributed Bragg reflector in which materials having different refractive indices are alternately stacked.

When the second contact electrode 140 includes a conductive oxide, the first insulating layer 150 includes a distributed Bragg reflector to improve the luminous efficiency of the light emitting device 100a. Alternatively, the second contact electrode 140 includes a conductive oxide, and the first insulating layer 150 is formed of a transparent insulating oxide (eg, SiO ₂ ) by forming the second contact electrode 140, An omnidirectional reflector formed by a stacked structure of the first insulating layer 150 and the first contact electrode 130 may be formed. In this case, the first contact electrode 130 is preferably formed to almost entirely cover the surface of the first insulating layer 150 except for a region exposing a portion of the second contact electrode 140 . Accordingly, a portion of the first insulating layer 150 may be interposed between the first contact electrode 130 and the second contact electrode 140 .

Furthermore, unlike illustrated, the first insulating layer 150 may further cover at least a portion of the side surface of the light emitting structure 120 . The degree to which the first insulating layer 150 covers the side surface of the light emitting structure 120 may vary depending on whether chip unit isolation is performed in the manufacturing process of the light emitting device. That is, as in the present embodiment, the first insulating layer 150 may be formed to cover only the upper surface of the light emitting structure 120 . On the other hand, after individualizing the wafer into chip units in the manufacturing process of the light emitting device 100 , When the first insulating layer 150 is formed, the first insulating layer 150 may cover up to the side surface of the light emitting structure 120 .

The first contact electrode 130 may partially cover the light emitting structure 120 . In addition, the first contact electrode 130 is in ohmic contact with the first conductive semiconductor layer 121 through the hole 120a and the opening of the first insulating layer 150 positioned at a portion corresponding to the hole 120a. do. In the present embodiment, the first contact electrode 130 may be formed to entirely cover a portion of the first insulating layer 150 except for a partial region. Accordingly, light may be reflected through the first contact electrode 130 . Also, the first contact electrode 130 may be electrically insulated from the second contact electrode 140 by the first insulating layer 150 .

Since the first contact electrode 130 is formed to entirely cover the upper surface of the light emitting structure 120 except for a partial region, current dissipation efficiency may be further improved. In addition, since the first contact electrode 130 may cover a portion not covered by the second contact electrode 140 , light may be reflected more effectively to improve the luminous efficiency of the light emitting device 100 .

As described above, the first contact electrode 130 may make an ohmic contact with the first conductivity type semiconductor layer 121 and may serve to reflect light. Accordingly, the first contact electrode 130 may include a highly reflective metal layer such as an Al layer. In this case, the first contact electrode 130 may be formed of a single layer or multiple layers. The highly reflective metal layer may be formed on an adhesive layer such as Ti, Cr, or Ni. However, the present invention is not limited thereto, and the first contact electrode 130 may include at least one of Ni, Pt, Pd, Rh, W, Ti, Al, Mg, Ag, and Au.

Also, unlike illustrated, the first contact electrode 130 may be formed to cover the side surface of the light emitting structure 120 . When the first contact electrode 130 is also formed on the side surface of the light emitting structure 120 , the light emitted from the side surface of the active layer 123 is reflected upward to increase the ratio of light emitted to the upper surface of the light emitting device 100 . . When the first contact electrode 130 is formed to cover the side surface of the light emitting structure 120 , the first insulating layer 150 may be interposed between the side surface of the light emitting structure 120 and the first contact electrode 130 . have.

Meanwhile, the light emitting device 100 may further include a connection electrode 145 . The connection electrode 145 may be positioned on the second contact electrode 140 , and may be electrically connected to the second contact electrode 140 through the opening of the first insulating layer 150 . Furthermore, the connection electrode 145 may electrically connect the second contact electrode 140 and the second bulk electrode 183 to each other. In addition, the connection electrode 145 may be formed to partially cover the first insulating layer 150 , and may be spaced apart from each other and insulated from the first contact electrode 130 .

The upper surface of the connection electrode 145 may be formed to have substantially the same height as the upper surface of the first contact electrode 130 . Also, the connection electrode 145 may be formed in the same process as the first contact electrode 130 , and the connection electrode 145 and the first contact electrode 130 may include the same material. However, the present invention is not limited thereto, and the connection electrode 145 and the first contact electrode 130 may include different materials.

The second insulating layer 160 may partially cover the first contact electrode 130 , and may form a first opening 160a partially exposing the first contact electrode 130 and a second contact electrode 140 . A second opening 160b partially exposed may be included. One or more of the first and second openings 160a and 160b may be formed.

The second insulating layer 160 may include an insulating material, for example, SiO ₂ , SiN _x , MgF ₂ . Furthermore, the second insulating layer 160 may include multiple layers, and may include a distributed Bragg reflector in which materials having different refractive indices are alternately stacked. When the second insulating layer 160 is formed of multiple layers, the uppermost layer of the second insulating layer 160 may be formed _{of SiN x .} Since the uppermost layer of the second insulating layer 160 _{is formed of SiN x} , it is possible to more effectively prevent moisture from penetrating into the light emitting structure 120 .

The stress buffer layer 170 is positioned on the insulating layers 150 and 160 . In particular, the stress buffer layer 170 may be positioned on the second insulating layer 160 . The stress buffer layer 170 may at least partially cover the upper surface of the second insulating layer 160 as shown. Alternatively, the stress buffer layer 170 may further cover a portion of the side surface of the second insulating layer 160 , and in this case, the stress buffer layer 170 may be in contact with the first contact electrode 130 and the connection electrode 145 . . That is, the stress buffer layer 170 may further cover side surfaces of the first and second openings 160a and 160b.

The stress buffer layer 170 serves to relieve stress generated when the light emitting device 100 is driven. When the light emitting device 100 is driven, the stress generated in the light emitting device 100 is relieved by the stress buffer layer 170 , thereby improving the mechanical stability of the light emitting device 100 and improving reliability.

Specifically, when the light emitting device 100 is driven, heat is generated while the light emitting structure 120 emits light. Coefficients of thermal expansion of the light emitting structure 120 , the first and second contact electrodes 130 and 140 , the insulating layers 150 and 160 , the first and second bulk electrodes 181 and 183 , and the insulating support 190 are all Since they are different, the extent to which each of the components is expanded by heat generated when the light emitting device 100 is driven is different. Accordingly, stress may be applied to the components, and strain may be generated in at least one component by the stress, and further, cracks or fractures may occur. In addition, when on/off of the light emitting device is repeated, stress is repeatedly generated, and fatigue failure of at least one of the components may also occur. In particular, when the light emitting device is driven with a high current, a relatively high driving heat is generated and the probability of failure or deterioration of the light emitting device is higher, and thus the reliability of the light emitting device is low.

On the other hand, the light emitting device 100 of the present embodiment may further include a stress buffer layer 170 to reduce stress and strain applied to the components. The stress buffer layer 170 may have a relatively large Young's modulus, and thus exhibit a low strain behavior even at high stress. Accordingly, energy is absorbed by the stress buffer layer 170 , so that the light emitting structure 120 , the first and second contact electrodes 130 and 140 , the insulating layers 150 and 160 , and the first and second bulk The stress applied to the electrodes 181 and 183 and the insulating support 190 may be reduced. The stress applied to the other components by the stress buffer layer 170 is relieved, and the mechanical stability of the light emitting device 100 is improved, and the probability of cracks and destruction is reduced, so that the reliability of the light emitting device 100 is improved. do.

In addition, the stress buffer layer 170 may have a lower residual stress (generated by a predetermined stress) than the insulating layers 150 and 160 and/or the insulating support 190 . Accordingly, the stress buffer layer 170 may relieve stress applied to the other components due to residual stress in the process of repeatedly turning on/off the light emitting device 100 . That is, since the light emitting device 100 includes the stress buffer layer 170 , the fatigue fracture strength of the light emitting device 100 is also increased, so that the reliability of the light emitting device 100 is improved.

In addition, the stress buffer layer 170 may have relatively excellent moisture absorption properties. In particular, the hygroscopicity of the stress buffer layer 170 may be lower than that of the insulating support 190 . Since the stress buffer layer 170 has relatively low hygroscopicity, it is possible to prevent cracks and peeling caused by moisture penetrating into the light emitting device 100 . In particular, when the insulating support 190 is formed of an epoxy molding compound (EMC), moisture permeates into the light emitting device 100 due to the high hygroscopicity of EMC, thereby causing peeling and cracking at the interface. According to the present embodiment, the stress buffer layer 170 prevents moisture absorption to prevent damage to the light emitting device 100 due to moisture, thereby improving the reliability of the light emitting device 100 .

In addition, adhesion between the stress buffer layer 170 and the insulating support 190 may be higher than that between the insulating layers 150 and 160 and the insulating support 190 . Therefore, compared to the case in which the insulating support 190 is formed on the second insulating layer 160, when the insulating support 190 is formed on the stress buffer layer 170, the probability of occurrence of separation or delamination at the interface is greatly reduced. . Accordingly, damage to the light emitting device 100 due to peeling of the insulating support 190 may be prevented, and reliability of the light emitting device 100 may be improved.

The stress buffer layer 170 having the above-described effects may include an insulating material having a stress relaxation behavior and further, an effect of preventing moisture permeation and improving adhesion. For example, the stress buffer layer may include at least one of polyimide, Teflon, benzocyclobutyne (BCB), and parylene. In particular, the stress buffer layer 170 may include a photosensitive material (eg, polyimide), and when the stress buffer layer 170 includes a photosensitive material, the stress buffer layer 170 may be formed only by the process of developing the photosensitive material. can Accordingly, a separate additional patterning process may be omitted, and thus the manufacturing process of the light emitting device 100 may be simplified. The stress buffer layer 170 may be in contact with the first bulk electrode 181 , the second bulk electrode 183 , and the insulating support 190 .

The thickness of the stress buffer layer 170 is not limited as long as it can obtain an effective stress relaxation behavior and moisture permeation prevention effect, and may have a thickness of, for example, about 2 to 30 μm. However, the present invention is not limited thereto.

The stress buffer layer 170 may be formed through deposition and patterning processes. Furthermore, the stress buffer layer 170 and the second insulating layer 160 may be simultaneously patterned. For example, first, the second insulating layer 160 covering the first contact electrode 130 is formed, and after the stress buffer layer 170 is formed on the second insulating layer 160 , the second insulating layer ( By simultaneously patterning 160 and the stress buffering layer 170 , the stress buffering layer 170 as shown may be provided. However, the present invention is not limited thereto.

The first bulk electrode 181 and the second bulk electrode 183 may be positioned on the light emitting structure 120 , and the first bulk electrode 181 and the second bulk electrode 183 may each be a first contact electrode ( 130 ) and the second contact electrode 140 . In particular, the first bulk electrode 181 and the second bulk electrode 183 may be electrically connected to each other by directly contacting the first and second contact electrodes 130 and 140 . In this case, the first bulk electrode 181 and the second bulk electrode 183 may be electrically connected to the first and second contact electrodes 130 and 140 through the first and second openings 160a and 160b, respectively. .

The first bulk electrode 181 and the second bulk electrode 183 may have a thickness of several tens of μm or more, for example, about 70 to 80 μm. Since the bulk electrodes 171 and 173 have a thickness in the above-described range, the light emitting device itself may be used as a chip scale package.

The first bulk electrode 181 and the second bulk electrode 183 may be formed of a single layer or multiple layers, and may include a material having electrical conductivity. For example, each of the first bulk electrode 181 and the second bulk electrode 183 may include Cu, Pt, Au, Ti, Ni, Al, Ag, or the like. Alternatively, the sintered metal particles and a non-metallic material interposed between the metal particles may be included. The first and second bulk electrodes 181 and 183 may be formed using plating, deposition, dotting, or screen printing.

Specifically, a case in which the first and second bulk electrodes 181 and 183 are formed using plating will be described first. A seed metal is formed on the entire surface of the stress buffer layer 170 , the first opening 160a and the second opening 160b by a method such as sputtering. The seed metal may include Ti, Cu, Au, Cr, or the like, and the seed metal may serve as an under bump metallization layer (UBM). For example, the seed metal may have a Ti/Cu stacked structure. Then, a mask is formed on the seed metal, wherein the mask masks a portion corresponding to the region where the insulating support 190 is formed, and opens the region where the first and second bulk electrodes 181 and 183 are formed. do. Next, first and second bulk electrodes 181 and 183 are formed in the open region of the mask through a plating process, and then the mask and the seed metal are removed through an etching process to remove the first and second bulk electrodes 181 . , 183) may be provided.

In addition, the case of forming the first and second bulk electrodes 181 and 183 using the screen printing method is as follows. A UBM layer is formed on at least a portion of the stress buffer layer 170 , the first opening 160a and the second opening 160b through a deposition and patterning method such as sputtering, or a deposition and lift-off method. The UBM layer may be formed on the region where the first and second bulk electrodes 181 and 183 are to be formed, and may include a (Ti or TiW) layer and a (Cu, Ni, Au single layer or a combination) layer. have. For example, the UBM layer may have a Ti/Cu stacked structure. Next, a mask is formed, but the mask masks a portion corresponding to the region where the insulating support 190 is formed, and opens the region where the first and second bulk electrodes 181 and 183 are formed. Next, a material such as Ag paste, Au paste, or Cu paste is formed in the open region through a screen printing process, and the material is cured. Thereafter, the first and second bulk electrodes 181 and 183 may be provided by removing the mask through an etching process.

The insulating support 190 is positioned on the light emitting structure 120 and at least partially covers side surfaces of the bulk electrodes 171 and 173 . The insulating support 190 has electrical insulation and covers the side surfaces of the first bulk electrode 181 and the second bulk electrode 183 to effectively insulate them from each other. At the same time, the insulating support 190 may serve to support the first bulk electrode 181 and the second bulk electrode 183 . The insulating support 190 may include, for example, a material such as an EMC (Epoxy Molding Compound) or a Si resin. In addition, the insulating support 190 may include light reflective and light scattering particles such as _{TiO 2 particles.} In particular, when the insulating support 190 includes EMC, as described above, the stress buffer layer 170 prevents the insulating support 190 from being separated and prevents moisture from penetrating into the insulating support 190 . have.

Meanwhile, the insulating support 190 and the first and second bulk electrodes 181 and 183 may contact the stress buffer layer 170 . Accordingly, when the light emitting device 100 is driven, the stress applied to the insulating support 190 and the first and second bulk electrodes 181 and 183 is more effectively relieved. As the stress is relieved, cracks or breakages in the insulating support 190 and the first and second bulk electrodes 181 and 183 may be prevented from occurring, and further, the insulating support 190, the first and second bulk electrodes may be prevented from occurring. The interface between the electrodes 181 and 183 may be peeled off to prevent the light emitting device 100 from being damaged.

In some embodiments, unlike illustrated, the insulating support 190 may cover the side surface of the light emitting structure 120 , and in this case, the light emission angle of the light emitted from the light emitting structure 120 may vary. For example, when the insulating support 190 further covers at least a portion of the side surface of the light emitting structure 120 , some of the light emitted to the side of the light emitting structure 120 may be reflected to the lower surface of the light emitting structure 120 . . In this way, by adjusting the region in which the insulating support 190 is disposed, the light emission angle of the light emitting device 100 can be adjusted.

Meanwhile, the light emitting device 100 may further include a pad electrode (not shown) positioned on the first and second bulk electrodes 181 and 183 . The pad electrode may serve to facilitate the mounting of the light emitting device 100 .

2A and 2B are cross-sectional and plan views illustrating a light emitting device according to another embodiment of the present invention. FIG. 2B shows a cross-section of a portion corresponding to line B-B' of FIG. 2A. The light emitting device 200 of FIGS. 2A and 2B is different from the light emitting device 100 of FIGS. 1A and 1B in the stress buffer layer 170, the first and second bulk electrodes 181 and 183, In addition, there is a difference in that it further includes a wavelength converter 210 . Hereinafter, the light emitting device 200 of the present embodiment will be described with a focus on the differences, and a detailed description of the overlapping configuration will be omitted below.

2A and 2B , the light emitting device 200 includes a light emitting structure 120 , a first contact electrode 130 , a second contact electrode 140 , insulating layers 150 and 160 , and a stress buffer layer 170 . , first and second bulk electrodes 181 and 183 and an insulating support 190 . Furthermore, the light emitting device 200 may further include a growth substrate (not shown), a connection electrode 145 , and a wavelength converter 210 .

In this embodiment, the stress buffer layer 170 may have a roughened surface 170R. That is, the surface, particularly, the upper surface of the stress buffer layer 170 may have an increased roughness through additional surface treatment. The roughness of the surface 170R of the stress buffer layer 170 may be increased through wet treatment and/or dry treatment, for example, wet treatment using KOH solution and/or _{dry treatment using O 2} and Ar plasma. A roughened surface 170R may be formed through the . By increasing the surface roughness of the stress buffer layer 170, the adhesiveness between the stress buffer layer 170 and the insulating support 190 on the stress buffer layer 170 and the first and second bulk electrodes 181 and 183 can be improved. have. Due to the improved adhesion, the light emitting device 200 with improved reliability is provided.

Furthermore, the first and second bulk electrodes 181 and 183 of the present embodiment may include surface-treated side surfaces 181s and 183s, respectively. By the surface treatment, at least one of the first and second bulk electrodes 181 and 183 may include a roughened surface formed on the side surface and/or an oxide film formed on the side surface. For example, by wet-treating the side surfaces of the first and second bulk electrodes 181 and 183 , a metal oxide film is formed on the side surfaces 181s and 183s of the first and second bulk electrodes 181 and 183 , or the side surface The roughness of (181s, 183s) can be increased. Accordingly, the adhesion between the first and second bulk electrodes 181 and 183 and the insulating support 190 is improved, thereby improving the mechanical stability of the light emitting device 200 .

Meanwhile, the light emitting device 200 may further include a wavelength conversion unit 210 . The wavelength converter 210 may be disposed on the lower surface of the light emitting structure 120 . Light emitted from the light emitting structure 120 by the wavelength conversion unit 210 is wavelength-converted to provide a light emitting device 200 capable of realizing light of various colors. In addition, the wavelength conversion unit 210 may be formed to extend not only to the lower surface of the light emitting structure 120 , but also to the side surface of the light emitting structure 120 , and further extend to the side surface of the insulating support 190 . have.

The wavelength converter 210 may include a material capable of converting a wavelength of light, for example, the wavelength converter 210 may be provided in a form in which a phosphor is dispersed in a carrier, or a single crystal phosphor sheet It may be provided in a form, or may be provided in a form including a quantum dot material. However, the present invention is not limited thereto.

Since the light emitting device 200 includes the wavelength converter 210 , a chip scale package capable of emitting white light may be provided.

3A and 3B are cross-sectional and plan views illustrating a light emitting device according to another embodiment of the present invention. FIG. 3B shows a cross-section of a portion corresponding to line C-C' of FIG. 3A. The light emitting device 300 of FIGS. 3A and 3B is different from the light emitting device 100 of FIGS. 1A and 1B in the structures of the first contact electrode 130 and the insulating layer 155 . Hereinafter, the light emitting device 200 of the present embodiment will be described with a focus on the differences, and a detailed description of the overlapping configuration will be omitted below.

3A and 3B , the light emitting device 300 includes a light emitting structure 120 , a first contact electrode 130 , a second contact electrode 140 , an insulating layer 155 , a stress buffer layer 170 , and a first It includes first and second bulk electrodes 181 and 183 and an insulating support 190 . Furthermore, the light emitting device 100 may further include a growth substrate (not shown) and a connection electrode 145 .

The light emitting device 300 includes a light emitting structure 120 , wherein the light emitting structure 120 includes a first conductivity type semiconductor layer 121 in which the second conductivity type semiconductor layer 125 and the active layer 123 are partially removed. This includes the exposed area. As the first conductivity type semiconductor layer 121 is exposed, the light emitting structure 120 may have a mesa including the second conductivity type semiconductor layer 125 and the active layer 123 . The location of the mesa is not limited, and for example, as illustrated, the mesa may be at least partially surrounded by the exposed region of the first conductivity-type semiconductor layer 121 .

The first contact electrode 130 may be in ohmic contact with the first conductivity type semiconductor layer 121 by being positioned on the region where the first conductivity type semiconductor layer 121 is exposed. In particular, unlike the exemplary embodiment of FIGS. 1A and 1B , the first contact electrode 130 is located in a region where the first conductivity-type semiconductor layer 121 is exposed. Accordingly, the first contact electrode 130 and the second contact electrode 140 may be spaced apart from each other.

The insulating layer 155 partially covers the first contact electrode 130 and the second contact electrode 140 , and a first opening partially exposing the first contact electrode 130 and the second contact electrode 140 , respectively. 155a and a second opening 155b. According to the present embodiment, since the first contact electrode 130 is located in the region where the first conductivity-type semiconductor layer 121 is exposed, the insulating layer 155 is formed between the first contact electrode 130 and the second contact electrode ( 140) may not be formed in a sandwiched form. In addition, since the insulating layer 155 may be formed in a single process without being separated into the first insulating layer and the second insulating layer, the manufacturing process of the light emitting device 200 may be further simplified. In particular, when the insulating layer is divided into the first insulating layer and the second insulating layer, a mask pattern forming process for patterning each insulating layer is required at least twice or more. On the other hand, in the present embodiment, since the insulating layer 155 is formed of a single insulating layer 155 , the mask pattern forming process may be omitted at least once.

Meanwhile, the connection electrode 145 may be positioned on the second contact electrode 140 . In addition, the side surface of the connection electrode 145 may be covered by the insulating layer 155 . According to the present embodiment, since the insulating layer 155 is formed of a single insulating layer 155 , the connection electrode 145 may be positioned under the insulating layer 155 .

However, the fact that the insulating layer 155 is formed of a single insulating layer 155 in this embodiment does not mean that the insulating layer 155 is formed of a single layer, and the insulating layer 155 is formed of a multilayer. can be done

4A and 4B are cross-sectional and plan views illustrating a light emitting device according to another embodiment of the present invention.

The structure of the light emitting structure 120 of the light emitting device 400 of this embodiment is different from that of the light emitting device 100 of FIGS. 1A and 1B . Accordingly, there is a difference in the mutual structural relationship of the other components, and the following will be described in detail focusing on the differences. A detailed description of the same configuration will be omitted.

4A (a) is a plan view of the light emitting device according to the present embodiment, (b) is a plan view for explaining the position of the hole (120h) and the position of the first opening (160a) and the second opening (160b), , FIG. 4B is a cross-sectional view showing a cross section of a region corresponding to the line D-D' of FIGS. 4A (a) and (b).

4A and 4B , the light emitting device 400 includes a light emitting structure 120 , a first contact electrode 130 , a second contact electrode 140 , insulating layers 150 and 160 , and a stress buffer layer 170 . , first and second bulk electrodes 181 and 183 and an insulating support 190 . Furthermore, the light emitting device 400 may further include a growth substrate (not shown) and a wavelength converter (not shown).

The light emitting structure 120 may include a region in which the second conductivity type semiconductor layer 125 and the active layer 123 are partially removed and the first conductivity type semiconductor layer 121 is partially exposed. For example, as shown, the light emitting structure 120 has a plurality of holes 120h penetrating through the second conductivity type semiconductor layer 125 and the active layer 123 to expose the first conductivity type semiconductor layer 121 . may include. The holes 120h may be located generally regularly throughout the light emitting structure 120 . However, the present invention is not limited thereto, and the arrangement shape and number of the holes 120h may be variously modified.

In addition, the shape in which the first conductivity type semiconductor layer 121 is exposed is not limited to the shape of the hole 120h. For example, the exposed region of the first conductivity-type semiconductor layer 121 may be formed in a line shape, a combination of holes and lines, or the like.

The second contact electrode 140 may be positioned on the second conductivity-type semiconductor layer 125 to make an ohmic contact. The second contact electrode 140 may be disposed to entirely cover the upper surface of the second conductivity-type semiconductor layer 125 , and further, may be formed to almost completely cover the upper surface of the second conductivity-type semiconductor layer 125 . have. The second contact electrode 140 may be formed as a single body throughout the light emitting structure 120 . In this case, the second contact electrode 140 may include opening regions corresponding to positions of the plurality of holes 120h. can Accordingly, current may be uniformly supplied to the entire light emitting structure 120 , and current dispersion efficiency may be improved.

However, the present invention is not limited thereto, and the second contact electrode 140 may be formed of a plurality of unit units.

The first insulating layer 150 may partially cover the upper surface of the light emitting structure 120 and the second contact electrode 140 . The first insulating layer 150 may cover side surfaces of the plurality of holes 120h and include openings for partially exposing the first conductivity-type semiconductor layer 121 positioned on the lower surface of the holes 120h. Accordingly, the opening may be positioned to correspond to a position where the plurality of holes 120h are disposed. Also, the first insulating layer 150 may include an opening exposing a portion of the second contact electrode 140 . Furthermore, the first insulating layer 150 may further cover at least a portion of the side surface of the light emitting structure 120 .

The first contact electrode 130 may partially cover the light emitting structure 120 , and through the openings of the holes 120h and the first insulating layer 150 positioned at portions corresponding to the holes 120h, the first contact electrode 130 may It may be in ohmic contact with the conductive semiconductor layer 121 . Also, unlike illustrated, the first contact electrode 130 may be formed to cover the side surface of the light emitting structure 120 .

The second insulating layer 160 may partially cover the first contact electrode 130 , and may form a first opening 160a partially exposing the first contact electrode 130 and a second contact electrode 140 . A second opening 160b partially exposed may be included. One or more of the first and second openings 160a and 160b may be formed. In addition, the openings 160a and 160b may be positioned to be biased on side surfaces positioned opposite to each other, respectively.

The stress buffer layer 170 may be positioned on the second insulating layer 160 and at least partially cover the surface of the second insulating layer 160 .

The first bulk electrode 181 and the second bulk electrode 183 may be positioned on the light emitting structure 120 , and the first bulk electrode 181 and the second bulk electrode 183 may each be a first contact electrode ( 130 ) and the second contact electrode 140 . The insulating support 190 is positioned on the light emitting structure 120 and at least partially covers side surfaces of the bulk electrodes 171 and 173 . In addition, the insulating support 190 and the first and second bulk electrodes 181 and 183 may contact the stress buffer layer 170 .

5 is an exploded perspective view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a lighting device.

Referring to FIG. 5 , the lighting device according to the present embodiment includes a diffusion cover 1010 , a light emitting device module 1020 , and a body portion 1030 . The body 1030 may accommodate the light emitting device module 1020 , and the diffusion cover 1010 may be disposed on the body 1030 to cover the upper portion of the light emitting device module 1020 .

The body portion 1030 is not limited as long as it can accommodate and support the light emitting device module 1020 and supply electrical power to the light emitting device module 1020 . For example, as shown, the body 1030 may include a body case 1031 , a power supply device 1033 , a power case 1035 , and a power connection unit 1037 .

The power supply device 1033 is accommodated in the power case 1035 , is electrically connected to the light emitting device module 1020 , and may include at least one IC chip. The IC chip may adjust, convert, or control characteristics of power supplied to the light emitting device module 1020 . The power case 1035 may accommodate and support the power supply 1033 , and the power case 1035 to which the power supply 1033 is fixed therein may be located inside the body case 1031 . . The power connection part 115 may be disposed at the lower end of the power case 1035 to be bound to the power case 1035 . Accordingly, the power connection unit 115 may be electrically connected to the power supply unit 1033 inside the power case 1035 , and may serve as a passage through which external power may be supplied to the power supply unit 1033 .

The light emitting device module 1020 includes a substrate 1023 and a light emitting device 1021 disposed on the substrate 1023 . The light emitting device module 1020 may be provided on the body case 1031 and electrically connected to the power supply 1033 .

The substrate 1023 is not limited as long as it is a substrate capable of supporting the light emitting device 1021 , and may be, for example, a printed circuit board including wiring. The substrate 1023 may have a shape corresponding to the fixing portion of the upper portion of the body case 1031 so as to be stably fixed to the body case 1031 . The light emitting device 1021 may include at least one of the light emitting devices according to the above-described embodiments of the present invention.

The diffusion cover 1010 may be disposed on the light emitting device 1021 , and may be fixed to the body case 1031 to cover the light emitting device 1021 . The diffusion cover 1010 may have a light-transmitting material, and by adjusting the shape and light transmittance of the diffusion cover 1010 , the directional characteristics of the lighting device may be adjusted. Therefore, the diffusion cover 1010 may be modified in various forms according to the purpose of use of the lighting device and the application aspect.

Since the lighting device of the present embodiment includes the light emitting device according to the embodiments of the present invention, a highly reliable high-power lighting device can be provided.

6A and 6B are exploded perspective and cross-sectional views, respectively, for explaining an example in which a light emitting device according to an embodiment of the present invention is applied to a display device. The cross-sectional view of FIG. 6(b) schematically shows a cross-section of a portion corresponding to the line I-I' of FIG. 6(a).

The display device of the present embodiment includes a display panel 2110 , a backlight unit BLU1 providing light to the display panel 2110 , and a panel guide 2100 supporting a lower edge of the display panel 2110 .

The display panel 2110 is not particularly limited and may be, for example, a liquid crystal display panel including a liquid crystal layer. The liquid crystal display panel may include a thin film transistor substrate and a color filter substrate bonded to face each other to maintain a uniform cell gap, and a liquid crystal layer interposed between the two substrates. Gate driving PCBs 2112 and 2113 for supplying driving signals to the gate lines may be further positioned at edges of the display panel 2110 . Here, the gate driving PCBs 2112 and 2113 are not formed on a separate PCB, but may be formed on a thin film transistor substrate. The gate driving PCBs 2112 and 2113 are electrically connected to the liquid crystal display panel 2110 by, for example, a chip on film (COF).

The backlight unit BLU1 includes a light source module including at least one substrate 2150 and a plurality of light emitting devices 2160 . Furthermore, the backlight unit BLU1 may further include a bottom cover 2180 , a reflective sheet 2170 , a diffusion plate 2131 , and optical sheets 2130 .

The bottom cover 2180 may be opened upward to accommodate the substrate 2150 , the light emitting device 2160 , the reflective sheet 2170 , the diffusion plate 2131 , and the optical sheets 2130 . Also, the bottom cover 2180 may be coupled to the panel guide 2100 . The substrate 2150 may be disposed under the reflective sheet 2170 to be surrounded by the reflective sheet 2170 . However, the present invention is not limited thereto, and when the reflective material is coated on the surface, it may be positioned on the reflective sheet 2170 . In addition, a plurality of substrates 2150 may be formed so that the plurality of substrates 2150 are arranged side by side, but the present invention is not limited thereto, and may be formed of a single substrate 2150 .

The light emitting device 2160 may include at least one of the light emitting devices according to the above-described embodiments of the present invention. The light emitting devices 2160 may be regularly arranged in a predetermined pattern on the substrate 2150 . In addition, a lens 2210 may be disposed on each light emitting device 2160 to improve uniformity of light emitted from the plurality of light emitting devices 2160 .

The diffusion plate 2131 and the optical sheets 2130 are positioned on the light emitting device 2160 . The light emitted from the light emitting device 2160 may be supplied to the display panel 2110 in the form of a surface light source through the diffusion plate 2131 and the optical sheets 2130 .

In this way, the light emitting device according to the embodiments of the present invention can be applied to the direct type display device as in the present embodiment.

7A and 7B are exploded perspective and cross-sectional views, respectively, for explaining an example in which a light emitting device according to an embodiment of the present invention is applied to a display device. The cross-sectional view of Fig. 7(b) schematically shows a cross-section of a portion corresponding to the line II-II' of Fig. 7(a).

The display device provided with the backlight unit according to the present embodiment includes a display panel 3210 on which an image is displayed, and a backlight unit BLU2 disposed on the rear surface of the display panel 3210 to irradiate light. Furthermore, the display device includes a frame 240 supporting the display panel 3210 and accommodating the backlight unit BLU2 , and covers 3240 and 3280 surrounding the display panel 3210 .

The display panel 3210 is not particularly limited, and may be, for example, a liquid crystal display panel including a liquid crystal layer. The liquid crystal display panel may include a thin film transistor substrate and a color filter substrate bonded to face each other to maintain a uniform cell gap, and a liquid crystal layer interposed between the two substrates. A gate driving PCB for supplying a driving signal to the gate line may be further positioned at an edge of the display panel 3210 . Here, the gate driving PCB is not formed on a separate PCB, but may be formed on the thin film transistor substrate. The gate driving PCB is electrically connected to the liquid crystal display panel 3210 by, for example, a chip on film (COF). The display panel 3210 is fixed by covers 3240 and 3280 positioned at upper and lower portions thereof, and the lower cover 3280 may be coupled to the backlight unit BLU2 .

The backlight unit BLU2 providing light to the display panel 3210 includes a lower cover 3270 having a partially opened upper surface, a light source module disposed on one side of the inner side of the lower cover 3270, and positioned in parallel with the light source module. and a light guide plate 3250 for converting point light into surface light. In addition, the backlight unit BLU2 of the present embodiment is disposed on the light guide plate 3250 and the optical sheets 3230 for diffusing and condensing light, and is disposed under the light guide plate 3250 and proceeds in the lower direction of the light guide plate 3250 . It may further include a reflective sheet 3260 for reflecting the light to the display panel 3210 direction.

The light source module includes a substrate 3220 and a plurality of light emitting devices 3110 spaced apart from each other at regular intervals on one surface of the substrate 3220 . The substrate 3220 is not limited as long as it supports the light emitting device 3110 and is electrically connected to the light emitting device 3110, and may be, for example, a printed circuit board. The light emitting device 3110 may include at least one light emitting device according to the above-described embodiments of the present invention. Light emitted from the light source module is incident on the light guide plate 3250 and is supplied to the display panel 3210 through the optical sheets 3230 . Through the light guide plate 3250 and the optical sheets 3230 , the point light source emitted from the light emitting devices 3110 may be transformed into a surface light source.

In this way, the light emitting device according to the embodiments of the present invention can be applied to the edge type display device as in the present embodiment.

According to the above-described embodiments of FIGS. 6 and 7 , a high-reliability light emitting device is included as a backlight unit of the display device. Accordingly, the luminance of the display device may be improved, and an output similar to that of a conventional backlight unit may be generated using only a relatively small number of light emitting devices, thereby simplifying the manufacturing process and reducing the manufacturing cost.

8 is a cross-sectional view illustrating an example in which a light emitting device according to an embodiment of the present invention is applied to a head lamp.

Referring to FIG. 8 , the head lamp includes a lamp body 4070 , a substrate 4020 , a light emitting device 4010 , and a cover lens 4050 . Furthermore, the head lamp may further include a heat dissipation unit 4030 , a support rack 4060 , and a connection member 4040 .

The substrate 4020 is fixed by the support rack 4060 and spaced apart from the lamp body 4070 . The substrate 4020 is not limited as long as it is a substrate capable of supporting the light emitting device 4010 , and may be, for example, a substrate having a conductive pattern such as a printed circuit board. The light emitting device 4010 is positioned on the substrate 4020 , and may be supported and fixed by the substrate 4020 . Also, the light emitting device 4010 may be electrically connected to an external power source through the conductive pattern of the substrate 4020 . In addition, the light emitting device 4010 may include at least one light emitting device according to the above-described embodiments of the present invention.

The cover lens 4050 is positioned on a path through which light emitted from the light emitting device 4010 travels. For example, as shown, the cover lens 4050 may be disposed to be spaced apart from the light emitting device 4010 by the connecting member 4040 and may be disposed in a direction in which the light emitted from the light emitting device 4010 is to be provided. can A beam angle and/or color of light emitted from the headlamp to the outside may be adjusted by the cover lens 4050 . Meanwhile, the connection member 4040 may serve as a light guide for fixing the cover lens 4050 to the substrate 4020 , as well as surrounding the light emitting device 4010 to provide a light emitting path 4045 . In this case, the connection member 4040 may be formed of a light reflective material or coated with a light reflective material. Meanwhile, the heat dissipation unit 4030 may include a heat dissipation fin 4031 and/or a heat dissipation fan 4033 , and radiates heat generated when the light emitting device 4010 is driven to the outside.

In this way, the light emitting device according to the embodiments of the present invention may be applied to the head lamp as in the present embodiment, in particular, a vehicle head lamp.

Since the headlamp of the present embodiment includes the light emitting device according to the embodiments of the present invention, a highly reliable high-power headlamp can be provided.

In the above, various embodiments of the present invention have been described, but the present invention is not limited to each of the above-described embodiments and features. The invention changed through the combination and substitution of technical features described in the embodiments is also included in the scope of the present invention, and various modifications and changes are possible within the scope without departing from the technical spirit of the claims of the present invention.

Claims (18)

a light emitting structure including a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, and an active layer positioned between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer;
first and second contact electrodes disposed on the light emitting structure and electrically connected to the first and second conductivity-type semiconductor layers, respectively;
an insulating material insulating the first contact electrode and the second contact electrode from each other;
a connection electrode positioned on the second contact electrode;
a stress buffer layer positioned on the insulating material; and
a first bulk electrode and a second bulk electrode disposed on the light emitting structure and the stress buffer layer and electrically connected to the first and second contact electrodes, respectively;
the connection electrode is positioned between the second bulk electrode and the second contact electrode;
The stress buffer layer is located between the insulating material and the bulk electrodes,
The stress buffer layer is a light emitting device having a roughened surface. The method according to claim 1,
The insulating material is a light emitting device comprising Si. The method according to claim 1,
The stress buffer layer is in contact with the first bulk electrode and the second bulk electrode. The light emitting device of claim 1, wherein the stress buffering layer comprises at least one selected from polyimide, Teflon, benzocyclobutyne, and parillin. The method according to claim 1,
The stress buffer layer is a light emitting device comprising a photosensitive material. The method according to claim 1,
The first and second bulk electrodes each include Cu, Pt, Au, Ti, Ni, Al, or Ag. The method according to claim 1,
and the connection electrode includes the same material as the first contact electrode. The method according to claim 1,
Further comprising an insulating support covering side surfaces of the first and second bulk electrodes and at least partially exposing upper surfaces of the first and second bulk electrodes;
The stress buffer layer is a light emitting device in contact with the first bulk electrode, the second bulk electrode, and the insulating support. 9. The method of claim 8,
The insulating support is positioned on the light emitting structure and at least partially covers the first and second bulk electrodes. 9. The method of claim 8,
The insulating support is a light emitting device comprising an EMC (Epoxy Molding Compound) or a silicone resin. 9. The method of claim 8,
The insulating support is a light emitting device comprising light scattering particles. 12. The method of claim 11,
The light scattering particles include TiO ₂ A light emitting device. 9. The method of claim 8,
The insulating support is a light emitting device covering a side surface of the light emitting structure. The method according to claim 1,
The light emitting device further comprising a wavelength conversion unit covering the lower surface of the light emitting structure. 15. The method of claim 14,
The wavelength conversion unit is formed to extend to a side surface of the light emitting structure. 15. The method of claim 14,
The wavelength conversion unit is a light emitting device comprising a carrier and a phosphor dispersed in the carrier. 15. The method of claim 14,
The wavelength converter includes a single-crystal phosphor sheet. 15. The method of claim 14,
The wavelength conversion unit is a light emitting device comprising a quantum dot material.

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