KR20130074081A - Light emitting device - Google Patents

Abstract

PURPOSE: A light emitting device is provided to emit inner light to the outside by forming a light extraction layer including dielectric layers and metal layers. CONSTITUTION: A light emitting structure (19) generates light. The light emitting structure includes a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer. A light extraction layer (27) is formed on the light emitting structure. The light extraction layer includes dielectric layers (25) and metal layers (23a,23b). The dielectric layers and the metal layers are laminated alternatively.

Description

[0001]

An embodiment relates to a light emitting device.

Light-emitting diodes (LEDs) are semiconductor light emitting devices that convert current into light.

BACKGROUND ART A semiconductor light emitting device can obtain light having high luminance and is widely used as a light source for a display, a light source for an automobile, and a light source for an illumination.

However, the semiconductor light emitting device has a problem in that light is not emitted to the outside, so the light extraction efficiency is low.

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

According to an embodiment, the light emitting device comprises: a light emitting structure for generating light; And a light extraction layer on the light emitting structure, wherein the light extraction layer includes a plurality of dielectric layers and a plurality of metal layers alternately stacked with each other to have a negative refractive index.

The embodiment can maximize light extraction efficiency by forming a light extraction layer in which a metal layer and a dielectric layer are stacked such that light is not reflected inside but reflected outside.

1 is a cross-sectional view illustrating a horizontal light emitting device according to a first embodiment.
FIG. 2 is a view illustrating the light extraction layer of FIG. 1.
3a and 3b are views showing the progress of light according to the refractive index.
4A, 4B and 4C are graphs illustrating the light traveling mechanism.
FIG. 5 is a view illustrating another light extraction layer of FIG. 1.
6 is a view showing a flip type light emitting device according to the second embodiment.
7 is a view showing a vertical light emitting device according to the third embodiment.
8 is an exploded perspective view of a display device according to an exemplary embodiment.
9 is a diagram illustrating a display device according to an exemplary embodiment.
10 is a perspective view of a lighting apparatus according to an embodiment.

In describing an embodiment according to the invention, in the case of being described as being formed "above" or "below" each element, the upper (upper) or lower (lower) Directly contacted or formed such that one or more other components are disposed between the two components. In addition, when expressed as "up (up) or down (down)" may include the meaning of the down direction as well as the up direction based on one component.

In the following description, "external" may mean air.

1 is a cross-sectional view illustrating a horizontal light emitting device according to a first embodiment.

Referring to FIG. 1, the horizontal light emitting device 10 according to the first embodiment may include a substrate 11, a light emitting structure 19, a transparent electrode layer 21, a light extraction layer 27, and first and second electrodes. (31, 33).

The light emitting structure 19 may include a first conductive semiconductor layer 13, an active layer 15, and a second conductive semiconductor layer 17.

The light emitting device 10 may reduce the lattice mismatch caused by the lattice constant difference between the substrate 11 and the first conductivity-type semiconductor layer 13, and thus the substrate 11 and the first conductivity-type semiconductor layer. A buffer layer may be further included between the (13), but is not limited thereto.

Defects such as cracks, voids, grains and bowing do not occur in the light emitting structure 19 formed on the substrate 11 by the buffer layer.

Although not shown, a non-conductive semiconductor layer containing no dopant may be further included between the buffer layer and the first conductive semiconductor layer 13, but embodiments are not limited thereto.

The buffer layer, the first conductive semiconductor layer 13, the active layer 15, and the second conductive semiconductor layer 17 may be formed of Group III and Group V compound semiconductor materials, but are not limited thereto.

The compound semiconductor material may include, for example, Al, In, Ga, and N, but is not limited thereto.

The substrate 11 may be formed of a material having excellent thermal conductivity and / or transmittance, but is not limited thereto. For example, the substrate 11 may be formed of at least one selected from the group consisting of sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, and Ge, but is not limited thereto. .

The first conductivity type semiconductor layer 13 may be formed under the substrate 11 or the buffer layer.

The first conductivity-type semiconductor layer 13 may be, for example, an n-type semiconductor layer including an n-type dopant, but is not limited thereto. The first conductivity type semiconductor layer 13 may include, for example, AlGaN or GaN, but is not limited thereto. The n-type dopant may include Si, Ge, or Sn, but is not limited thereto.

The first conductive semiconductor layer 13 serves as a conductive layer for supplying a first carrier, for example, electrons, to the active layer 15, and a second carrier, for example, a hole, of the active layer 15. It can serve as a barrier layer to prevent holes from falling into the buffer layer.

The dopant having a high concentration is doped into the first conductive semiconductor layer 13, and thus may serve as a conductive layer through which electrons can move freely.

The first conductivity-type semiconductor layer 13 is formed of a compound semiconductor material having a band gap greater than or equal to that of the active layer 15, and thus serves as a barrier layer to prevent holes of the active layer 15 from falling into the buffer layer. can do.

The active layer 15 may be formed under the first conductive semiconductor layer 13.

For example, the active layer 15 may recombine electrons supplied from the first conductive semiconductor layer 13 and holes supplied from the second conductive semiconductor layer 17 to emit ultraviolet light. In order to generate ultraviolet light, the active layer 15 should have at least a wide bandgap.

The active layer 15 may include any one of a single quantum well structure (SQW), a multiple quantum well structure (MQW), a quantum dot structure, and a quantum line structure.

The active layer 15 may be formed by one or a periodic repetition thereof selected from GaN, InGaN, AlGaN, and AlInGaN.

The active layer 15 of the embodiment may generate light having a wavelength of 365 nm to 488 nm, but is not limited thereto.

For example, the active layer 15 may generate light of any one of 365 nm wavelength light, 405 nm wavelength light, and 488 nm wavelength light.

The second conductivity type semiconductor layer 17 may be formed under the active layer 15.

The second conductive semiconductor layer 17 may be, for example, a p-type semiconductor layer including a p-type dopant, but is not limited thereto. The second conductivity type semiconductor layer 17 may be, for example, AlGaN or GaN, but is not limited thereto. The p-type dopant may include Mg, Zn, Ca, Sr or Ba, but is not limited thereto.

The second conductive semiconductor layer 17 may serve as a conductive layer for supplying holes to the active layer 15.

A high concentration of dopant is doped into the second conductive semiconductor layer 17, and thus may serve as a conductive layer through which holes may freely move.

A third conductivity type semiconductor layer is formed between the active layer 15 and the second conductivity type semiconductor layer 17 to prevent electrons of the active layer 15 from falling into the second conductivity type semiconductor layer 17. However, the present invention is not limited thereto.

In order to more reliably prevent electrons in the active layer 15 from being transferred to the second conductivity type semiconductor layer 17, the active layer 15 and the second conductivity type semiconductor layer 17 or the third conductivity type semiconductor. An electron blocking layer may be formed between the layers, but is not limited thereto.

For example, the third conductivity type semiconductor layer and the electron blocking layer may be formed of AlGaN, but are not limited thereto.

For example, the electron blocking layer may have a band gap larger than at least the third conductivity type semiconductor layer, but is not limited thereto.

For example, when the third conductivity type semiconductor layer and the electron blocking layer are formed of AlGaN, the electron blocking layer is formed in the third layer so that the electron blocking layer has a larger band gap than the third conductivity type semiconductor layer. It may have a higher Al content than the conductive semiconductor layer, but is not limited thereto.

The transparent electrode layer 21 may be formed on the second conductive semiconductor layer 17. The transparent electrode layer 21 may serve as a conductive layer to obtain a spreading effect of supplying power to a wider area of the second conductive semiconductor layer 17. In addition, the transparent electrode layer 21 may be formed of a material having excellent transparency in order to emit light to the outside.

The transparent electrode layer 21 may include ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx, At least one selected from the group consisting of RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO may be included, but is not limited thereto.

The light extraction layer 27 may be formed on the transparent electrode layer 21.

The light extraction layer 27 may serve to improve light extraction efficiency by allowing the light to be emitted to the outside without allowing the light to stay inside the light emitting device 10.

Typically, light generated in the active layer 15 may travel in all directions. Some light may travel to the substrate 11 via the first conductive semiconductor layer 13, and some light may travel to the transparent electrode layer 21 via the second conductive semiconductor layer 17. have.

The light emitting structure 19 has a higher refractive index than outside air. Therefore, the light propagated to the second conductive semiconductor layer 17 or the transparent electrode layer 21 may be emitted to the outside or reflected to the inside.

That is, light incident at an angle of incidence greater than or equal to a predetermined angle with respect to the second conductivity-type semiconductor layer 17 or the transparent electrode layer 21 may be totally internally reflected without being emitted to the outside.

In other words, as shown in FIG. 3A, when light is incident on a medium having a refractive index greater than zero, the light incident at an angle of 17 ° or more may be totally internally reflected.

In contrast, when light is incident on a medium having a refractive index smaller than zero (hereinafter referred to as negative refractive index), only light incident at an angle of 90 ° or more may be totally reflected.

3A and 3B, when using a medium having a negative refractive index, it can be seen that most of the light is emitted to the outside.

The light extraction layer 27 of the embodiment is designed to have a negative refractive index, thereby maximizing light extraction efficiency.

As illustrated in FIG. 2, the light extraction layer 27 may include a multi-layer in which metal layers 23a and 23b and dielectric layers 25 are stacked.

Metal materials are used as the metal layers 23a and 23b, for example, aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), platinum (Pt), gold (Au), and tungsten (W). One selected from the group consisting of copper (Cu) and molybdenum (Mo) may be used, but is not limited thereto.

As the dielectric layer 25, a transparent oxide based material, a transparent nitride based material, or a carbide based material may be used.

For example, transparent oxide-based materials include ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx One selected from the group consisting of SiO 2 and SiO _x can be used, but is not limited thereto.

Among these oxide-based materials, ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, and RuOx are conductive. As a result, it can serve as a current spreading.

For example, the transparent nitride-based material may be Si ₃ N ₄ or Si _x N _y , but is not limited thereto.

For example, the transparent carbide-based material may be SiC, but is not limited thereto.

Although only the three-layer structure of the first metal layer 23a, the dielectric layer 25, and the second metal layer 23b is shown in FIG. 2, the light extraction layer 27 of the embodiment may be three or more layers.

That is, as shown in FIG. 5, the light extraction layer 27A of the embodiment may include a multi-layer in which a plurality of metal layers 101 and a plurality of dielectric layers 103 are alternately arranged.

In this multi-layer, the lowermost layer and the uppermost layer may be the metal layer 10.

The metal layer 101 may serve to determine the transmission of light. That is, depending on the design of the metal layer 101, light may be transmitted or light may be absorbed.

In the following embodiments, for convenience of description, the metal layers 23a and 23b and the dielectric layer 25 of FIG. 2 will be described.

As shown in Figs. 4A to 4C, the metal layers 23a and 23b have a unique plasma frequency ω _p and a unique plasma momentum k _p according to the metal material type.

In contrast, light may have its own wavelength frequency ω depending on the type of material of the active layer 15.

In addition, there is momentum k _z in the z-axis direction in the direction parallel to the plane of the metal layers 23a and 23b or the dielectric layer 25 in the light extraction layer 27, and the metal layers 23a and 23b or the dielectric layer 25 are present. Momentum k _x in the x-axis direction may exist in a direction perpendicular to the plane of.

In this case, as shown in FIG. 4, the ratio of the frequency ω of light at the plasma frequency ω _p of the metal layers 23a and 23b is about 0.6 according to the z-axis momentum k _z as in the band II region. It can be seen that it has a negative refractive index characteristic at.

Figure 4c is the horizontal axis shows the plasma momentum momentum (k _z) z-axis of the (k _p), and the vertical axis shows the momentum along the x axis _(x k) for a plasma momentum (k _p).

As shown in FIG. 4C, it has a negative refractive index characteristic for the z-axis momentum.

Due to the negative refractive index characteristic, even though the light is incident on the light extraction layer 27 at an incident angle of about 90 °, the light may be emitted to the outside without being reflected inside.

The light extraction layer 27 of the embodiment may have a thickness of 0.2 lambda _p , but the metal layers 23a and 23b and the dielectric layer 25 may have a thickness of 0.2 lambda _p in order to have such a refractive index characteristic. Here, λ _p may represent the wavelength of the plasma frequency (ω _p) of the metal layer (23a, 23b).

Since λ _p depends on the type of material of the metal layers 23a and 23b, the thicknesses of the metal layers 23a and 23b and the dielectric layer 25 also depend on which metal material the metal layers 23a and 23b are used as. Can be.

For example, when silver (Ag) is used as the metal material, the plasma wavelength λ _p of silver (Ag) may be approximately 137.61 nm. In this case, the thicknesses of the metal layers 23a and 23b and the dielectric layer 25 may be 0.2 * 137.61 = 27.522 nm.

The thicknesses of the metal layers 23a and 23b and the dielectric layer 25 may be the same as or different from each other.

For example, the thickness of the metal layers 23a and 23b is 0.2 lambda _p , whereas the thickness of the dielectric layer 25 may be designed to be larger or smaller than 0.2 lambda _p , but is not limited thereto.

Accordingly, the material of the metal layers 23a and 23b and the material of the dielectric layer 25 are selected according to the wavelength of the light of the active layer 15, and the thicknesses of the metal layers 23a and 23b and the dielectric layer 25 are selected. Although the extraction layer 27 is regarded as a medium having a single negative refractive index characteristic, light may be transmitted despite the opaque metal layers 23a and 23b. Since the light is emitted to the outside instead of totally internally reflected by the light extraction layer 27 having the negative refractive index characteristic, the light extraction efficiency may be remarkably improved.

For example, when the light having a wavelength of 365 nm or the light having a wavelength of 405 nm is used as silver (Ag) as the metal layers 23a and 23b and ITO or Si ₃ N ₄ is used as the dielectric layer 25, the metal layers 23a and 23b and the dielectric layer are used. 25 may be emitted to the outside through the stacked light extraction layers 27.

For example, when light of 488 nm is used as silver (Ag) as the metal layers 23a and 23b and SiC is used as the dielectric layer 25, the light extraction layer in which the metal layers 23a and 23b and the dielectric layer 25 are stacked ( 27) can be emitted to the outside.

The light incident on the light extraction layer 27 may be reflected to the outside based on a boundary surface set in a direction perpendicular to the plane of the light extraction layer 27.

For example, when the light is incident in the left and right diagonal directions of the light extraction layer 27, the light may be reflected to the left and right diagonal directions with respect to the vertical boundary of the light extraction layer 27 and may be emitted to the outside.

A first electrode 31 is formed on the first conductive semiconductor layer 13, and a second electrode 33 is formed on the light emitting structure 19, that is, the second conductive semiconductor layer 17. Can be.

When the material of the dielectric layer 25 of the light extraction layer 27, for example, ITO is conductive, the second electrode 33 may be formed on the light extraction layer 27.

In contrast, when the material of the dielectric layer 25 of the light extraction layer 27, for example, SiC, is not conductive, the rear surface of the second electrode 33 is in contact with at least the second conductivity type semiconductor layer 17. It can be formed to. In this case, the second electrode 33 may be connected to the second conductive semiconductor layer 17 by passing through the light extraction layer 27 and the transparent electrode layer 21, for example.

Since the upper surface of the second electrode 33 should serve as a pad for supplying power, the second electrode 33 may have a size at least larger than that of the through-holes of the light extraction layer 27 or the transparent electrode layer 21.

The second electrode 33 may have first and second back surfaces, and the first back surface penetrates the light extraction layer 27 and the transparent electrode layer 21 to form the second conductive semiconductor layer 17. The second back surface may be formed to contact a portion of the upper surface of the light extraction layer 27, specifically, the metal layers 23a and 23b on the uppermost layer.

As the second electrode 33 is formed to penetrate the light extraction layer 27 or the transparent electrode layer 21, the bonding force of the second electrode 33 may be further improved.

Meanwhile, at least a side surface of the light emitting structure 19, that is, at least a side surface of the light emitting structure 19 in order to prevent electrical short between the first conductive semiconductor layer 13 and the second conductive semiconductor layer 17. The protective layer 29 may be formed.

The protective layer 29 may be formed of a material having excellent transparency and low conductivity or an insulating material, for example, SiO ₂ , Si _x O _y , Si ₃ N ₄ , Si _x N _y , Al ₂ O _3, and TiO ₂ . At least one selected from the group consisting of, but is not limited thereto.

In the first exemplary embodiment, the light extraction layer 27 in which the metal layers 23a and 23b and the dielectric layer 25 are stacked may be maximized so that light is not reflected inside but reflected outside.

Although not shown in the drawings for the first embodiment, the light of the active layer 15 proceeds to the substrate 11 and is reflected from the substrate 11 to form the first conductive semiconductor layer (1) formed of the first electrode 31 ( 13, a light extraction layer 27 may be further formed on the first conductivity-type semiconductor layer 13 on which the first electrode 31 is formed so as to emit more light to the outside. That is, the light extraction layer 27 may be formed on all upper surfaces of the first conductive semiconductor layer 13 except for the first electrode 31.

If the light extraction layer 27 is formed on the first conductive semiconductor layer 13 on which the first electrode 31 is formed, the first conductive semiconductor layer 13 on which the first electrode 31 is formed It may not be formed on the phase. In this case, the passivation layer 29 may be formed in the edge region of the side surface of the light emitting structure 19 and the upper surface of the light extraction layer 27 in which the second electrode 33 is formed.

6 is a view showing a flip type light emitting device according to the second embodiment.

In the second embodiment, the reflective layer 35 is used instead of the transparent electrode layer 21 of the first embodiment, and the light extraction layer 27 is formed on the substrate 11 layer on the substrate 11, while the light emitting element is turned over. It is almost the same as the first embodiment except that it is used.

In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

Referring to FIG. 6, the flip type light emitting device 10A according to the second embodiment may include a substrate 11, a light emitting structure 19, a reflective layer 35, a light extraction layer 27, and first and second electrodes 31. , 33).

Although not shown, as in the first embodiment, the protective layer 29 may be formed to prevent electrical short of the side surface of the light emitting structure 19.

The light emitting device 10 according to the first exemplary embodiment may have a structure in which light is emitted to the outside through the second conductive semiconductor layer 17 or the transparent electrode layer 21.

In contrast, the light emitting device 10A according to the second embodiment may have a structure in which light is emitted to the outside through the substrate 11.

Therefore, in order to emit more light traveling to the substrate 11 to the outside, a light extraction layer 27 may be formed on the substrate 11.

Since the configuration and the operation function of the light extraction layer 27 have already been described in detail in the first embodiment, further description thereof will be omitted.

As the light extraction layer 27 is formed on the substrate 11, the light propagated from the active layer 15 through the substrate 11 to the light extraction layer 27 is not totally internally reflected and the light extraction is performed. It may be reflected to the outside based on the boundary surface set in the direction perpendicular to the plane of the layer 27.

The reflective layer 35 may be formed of, for example, a metal material having excellent conductivity and reflectivity, and one selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf. Or an alloy thereof, but is not limited thereto.

When the reflective layer 35 is not excellent in conductivity, the power supplied to the second electrode 33 may be difficult to be supplied to the second conductive semiconductor layer 17 by the reflective layer 35.

In the second embodiment, the light extraction layer 27 in which the metal layers 23a and 23b and the dielectric layer 25 are stacked may be maximized so that the light is not reflected inside but reflected outside.

7 is a view showing a vertical light emitting device according to the third embodiment.

Referring to FIG. 7, in the horizontal light emitting device 10 according to the first embodiment, the channel layer 43, the electrode layer 45, the bonding layer 47, and the conductive support are formed on the second conductive semiconductor layer 17. The member 49 may be formed and flipped 180 degrees, and then the substrate 11 may be removed. Subsequently, a side surface of the light emitting structure 19 may be inclined through mesa etching, and a light extraction layer 27 may be formed on the top surface of the first conductivity type semiconductor layer 13 to improve light extraction. Subsequently, in order to protect the light emitting structure 19, a protective layer 51 is formed on a side surface of the light emitting structure 19, an upper surface of the channel layer 43, and a portion of the upper surface of the light emitting structure 19. The electrode 53 may be formed on the 27. In this manner, the vertical light emitting device 10B according to the third embodiment may be manufactured.

Since the structure and function of the light extraction layer 27 are the same as those of the first embodiment, detailed description thereof will be omitted.

The electrode layer 45 may be formed of a material having reflective properties for reflecting light and conductive properties for supplying power to the light emitting structure 19. The electrode layer 45 may be formed of at least one or an alloy thereof, for example, selected from the group consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf. It is not limited.

The conductive support member is formed of a conductive material through which electricity can flow. For example, the conductive support member may be formed of at least one selected from the group consisting of Cu, Au, Ni, Mo, and Cu-W, but is not limited thereto.

The protective layer 51 may be formed of the same material as the channel layer 43, but is not limited thereto.

The channel layer 43 and the protective layer 51 may be formed of one of an oxide, a nitride, and an insulating material. The channel layer 43 and the protective layer 51 may include, for example, ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, ATO, GZO, SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , At least one selected from the group consisting of Al ₂ O ₃ , and TiO ₂ .

The electrode 53 may be formed through the light extraction layer 27 like the second electrode 33 of the first embodiment. That is, the electrode 53 includes first and second rear surfaces, and the first rear surface penetrates through the light extraction layer 27 to contact the first conductive semiconductor layer 13. The second back surface may be formed to contact a portion of the upper surface of the light extraction layer 27, specifically, the metal layers 23a and 23b, which are uppermost layers of the light extraction layer 27.

As such, the first rear surface of the electrode 53 is in contact with the inner side surface of the light extraction layer 27 and the surface of the first conductive semiconductor layer 13, and the second rear surface of the electrode 53 is the light. The adhesion performance of the electrode 53 can be improved by making contact with a partial region of the upper surface of the metal layers 23a and 23b which is the uppermost layer of the extraction layer 27.

On the other hand, the current blocking layer 41 for preventing the concentration of the current in the vertical direction may be formed to overlap the electrode 53 in the vertical direction.

The current blocking layer 41 may be formed of the same material as the protective layer 51 and the channel layer 43, but is not limited thereto.

The light emitting device 10 according to the embodiment may be applied to a light unit. The light unit includes a structure in which a plurality of light emitting elements 10 are arranged, and includes a display device shown in FIGS. 8 and 9 and a lighting device shown in FIG. 10, and includes a lighting lamp, a traffic light, a vehicle headlamp, and an electric sign. Can be applied to units such as indicators.

8 is an exploded perspective view of the display device according to the embodiment.

Referring to FIG. 8, the display device 1000 includes a light guide plate 1041, a light emitting module 1031 providing light to the light guide plate 1041, a reflective member 1022 under the light guide plate 1041, and A bottom cover 1011 that houses an optical sheet 1051 on the light guide plate 1041, a display panel 1061 on the optical sheet 1051, the light guide plate 1041, a light emitting module 1031, and a reflective member 1022. ), But is not limited thereto.

The bottom cover 1011, the reflective sheet 1022, the light guide plate 1041, and the optical sheet 1051 can be defined as a light unit 1050.

The light guide plate 1041 serves to diffuse the light provided from the light emitting module 1031 to make a surface light source. The light guide plate 1041 is made of a transparent material, for example, acrylic resin-based such as polymethyl metaacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphthalate (PEN). It may include one of the resins.

The light emitting module 1031 is disposed on at least one side of the light guide plate 1041 to provide light to at least one side of the light guide plate 1041, and ultimately serves as a light source of the display device.

At least one light emitting module 1031 may be disposed in the bottom cover, and may provide light directly or indirectly at one side of the light guide plate 1041. The light emitting module 1031 may include a substrate 1033 and a light emitting device 10 according to the embodiment disclosed above, and the light emitting device 10 may be arranged on the substrate 1033 at predetermined intervals. The substrate may be a printed circuit board, but is not limited thereto. In addition, the substrate 1033 may include a metal core PCB (MCPCB, Metal Core PCB), flexible PCB (FPCB, Flexible PCB) and the like, but is not limited thereto. When the light emitting device 10 is mounted on the side surface of the bottom cover 1011 or the heat dissipation plate, the substrate 1033 may be removed. A part of the heat radiation plate may be in contact with the upper surface of the bottom cover 1011. Therefore, heat generated in the light emitting device 10 may be discharged to the bottom cover 1011 via the heat dissipation plate.

The plurality of light emitting devices 10 may be mounted on the substrate 1033 such that an emission surface from which light is emitted is spaced apart from the light guide plate 1041 by a predetermined distance, but is not limited thereto. The light emitting device 10 may directly or indirectly provide light to a light incident part, which is one side of the light guide plate 1041, but is not limited thereto.

The reflective member 1022 may be disposed under the light guide plate 1041. The reflective member 1022 reflects the light incident on the lower surface of the light guide plate 1041 and supplies the reflected light to the display panel 1061 to improve the brightness of the display panel 1061. The reflective member 1022 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto. The reflective member 1022 may be an upper surface of the bottom cover 1011, but is not limited thereto.

The bottom cover 1011 may house the light guide plate 1041, the light emitting module 1031, the reflective member 1022, and the like. To this end, the bottom cover 1011 may be provided with a housing portion 1012 having a box-like shape with an opened upper surface, but the present invention is not limited thereto. The bottom cover 1011 may be coupled to a top cover (not shown), but is not limited thereto.

The bottom cover 1011 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. In addition, the bottom cover 1011 may include a metal or a non-metal material having good thermal conductivity, but the present invention is not limited thereto.

The display panel 1061 is, for example, an LCD panel, and includes a first and second substrates of transparent materials facing each other, and a liquid crystal layer interposed between the first and second substrates. A polarizing plate may be attached to at least one surface of the display panel 1061, but the present invention is not limited thereto. The display panel 1061 displays information by transmitting or blocking light provided from the light emitting module 1031. The display device 1000 can be applied to video display devices such as portable terminals, monitors of notebook computers, monitors of laptop computers, and televisions.

The optical sheet 1051 is disposed between the display panel 1061 and the light guide plate 1041 and includes at least one light-transmitting sheet. The optical sheet 1051 may include at least one of a sheet such as a diffusion sheet, a horizontal / vertical prism sheet, a brightness enhanced sheet, and the like. The diffusion sheet diffuses incident light, and the horizontal and / or vertical prism sheet concentrates incident light on the display panel 1061. The brightness enhancing sheet reuses the lost light to improve the brightness I will. A protective sheet may be disposed on the display panel 1061, but the present invention is not limited thereto.

The light guide plate 1041 and the optical sheet 1051 may be included as an optical member on the optical path of the light emitting module 1031, but are not limited thereto.

9 is a view showing a display device having a light emitting device according to an embodiment.

Referring to FIG. 9, the display device 1100 includes a bottom cover 1152, a substrate 1120 on which the light emitting device 10 disclosed above is arranged, an optical member 1154, and a display panel 1155.

The substrate 1120 and the light emitting device 10 may be defined as a light emitting module 1160. The bottom cover 1152, the at least one light emitting module 1160, and the optical member 1154 may be defined as a light unit (not shown).

The bottom cover 1152 may include a receiving portion 1153, but the present invention is not limited thereto.

The optical member 1154 may include at least one of a lens, a light guide plate, a diffusion sheet, a horizontal and vertical prism sheet, and a brightness enhancement sheet. The light guide plate may be made of a PC material or a PMMA (poly methy methacrylate) material, and such a light guide plate may be removed. The diffusion sheet diffuses the incident light, and the horizontal and vertical prism sheets condense the incident light onto the display panel 1155. The brightness enhancing sheet reuses the lost light to improve the brightness .

The optical member 1154 is disposed on the light emitting module 1060, and performs surface light source, diffusion, and light condensation of the light emitted from the light emitting module 1060.

10 is a perspective view of a lighting apparatus according to an embodiment.

Referring to FIG. 10, the lighting device 1500 may include a case 1510, a light emitting module 1530 installed in the case 1510, and a connection terminal installed in the case 1510 and receiving power from an external power source. 1520).

The case 1510 may be formed of a material having good heat dissipation, for example, may be formed of a metal material or a resin material.

The light emitting module 1530 may include a substrate 1532 and a light emitting device 10 according to an embodiment mounted on the substrate 1532. The plurality of light emitting devices 10 may be arranged in a matrix form or spaced apart at predetermined intervals.

The substrate 1532 may be a circuit pattern printed on an insulator. For example, a general printed circuit board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB, FR-4 substrates and the like.

In addition, the substrate 1532 may be formed of a material that reflects light efficiently, or a surface may be coated with a color, for example, white or silver, in which the light is efficiently reflected.

At least one light emitting device 10 may be mounted on the substrate 1532. Each of the light emitting devices 10 may include at least one light emitting diode (LED) chip. The LED chip may include a light emitting diode in a visible light band such as red, green, blue, or white, or a UV light emitting diode emitting ultraviolet (UV) light.

The light emitting module 1530 may be arranged to have a combination of various light emitting devices 10 to obtain color and luminance. For example, a white light emitting diode, a red light emitting diode, and a green light emitting diode may be combined to secure high color rendering (CRI).

The connection terminal 1520 may be electrically connected to the light emitting module 1530 to supply power. The connection terminal 1520 is inserted into and coupled to an external power source in a socket manner, but is not limited thereto. For example, the connection terminal 1520 may be formed in a pin shape and inserted into an external power source, or may be connected to the external power source by a wire.

10, 10A, 10B: light emitting element
11: substrate
13: First conductive type semiconductor layer
15:
17: second conductivity type semiconductor layer
19: light emitting structure
21: transparent electrode layer
23a, 23b, 101: metal layer
25, 103: dielectric layer
27, 27A: light extraction layer
29, 51: protective layer
31: first electrode
33: Second electrode
35: reflective layer
41: current blocking layer
43: channel layer
45: electrode layer
47: bonding layer
49: conductive support member
53: electrode

Claims (20)

A light emitting structure for generating light; And
A light extraction layer on the light emitting structure,
The light extraction layer,
A light emitting device comprising a plurality of dielectric layers and a plurality of metal layers alternately stacked on each other to have a negative refractive index. The method of claim 1,
The light emitting structure,
A first conductive semiconductor layer;
An active layer formed on the first conductive semiconductor layer; And
A light emitting device comprising a second conductivity type semiconductor layer formed on the active layer. The method of claim 2,
The light extraction layer is formed on the second conductivity type semiconductor layer,
A first electrode formed on the first conductive semiconductor layer; And
The light emitting device further comprises a second electrode formed on the light extraction layer. The method of claim 3,
The second electrode is formed to penetrate the light extraction layer to contact the second conductive semiconductor layer. The method of claim 3,
The light emitting device further comprises a transparent electrode layer formed between the second conductivity-type semiconductor layer and the light extraction layer. The method of claim 1,
The metal layer is formed in contact with the upper surface of the second conductive semiconductor layer. The method of claim 2,
Further comprising a substrate formed under the first conductive semiconductor layer,
The light extracting layer is formed under the substrate. The method of claim 7, wherein
A reflective layer formed on the second conductive semiconductor layer;
A first electrode formed on the first conductive semiconductor layer; And
The light emitting device further comprises a second electrode formed on the reflective layer. The method of claim 7, wherein
The metal layer of the light extraction layer is formed in contact with the back of the substrate. The method of claim 2,
The light extraction layer is formed under the first conductivity type semiconductor layer,
An electrode formed under the light extraction layer;
An electrode layer on the second conductivity type semiconductor layer; And
And a channel layer formed along an outer edge region of the second conductive semiconductor layer. The method of claim 10,
The metal layer of the light extraction layer is formed in contact with the back surface of the first conductivity type semiconductor layer. The method of claim 1,
The lowermost layer and the uppermost layer of the light extraction layer is a metal layer. The method of claim 1,
The dielectric layer is one of an oxide-based material, a nitride-based material and a carbide-based material. The method of claim 1,
The metal layer is made of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), platinum (Pt), gold (Au), tungsten (W), copper (Cu), and molybdenum (Mo). A light emitting device comprising one selected from the group consisting of. The method of claim 1,
And the dielectric layer and the metal layer have the same thickness. 17. The method of claim 16,
Wherein the thickness is 0.2λ _p and λ _p is the intrinsic wavelength of the material of the metal layer. The method of claim 2,
And a material of the dielectric layer and a material of the metal layer are determined according to the wavelength of light generated in the active layer. 18. The method of claim 17,
When the light has a wavelength of 365 nm, the dielectric layer is one of ITO and Si ₃ N ₄ , and the dielectric layer is silver (Ag). 18. The method of claim 17,
Wherein when the light has a wavelength of 405 nm, the dielectric layer is one of ITO and Si ₃ N ₄ , and the dielectric layer is silver (Ag). 18. The method of claim 17,
Wherein the light has a wavelength of 488 nm, the dielectric layer is SiC and the metal layer is silver (Ag).

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