KR20120037772A - Light emitting device - Google Patents

Light emitting device Download PDF

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Publication number
KR20120037772A
KR20120037772A KR1020100099429A KR20100099429A KR20120037772A KR 20120037772 A KR20120037772 A KR 20120037772A KR 1020100099429 A KR1020100099429 A KR 1020100099429A KR 20100099429 A KR20100099429 A KR 20100099429A KR 20120037772 A KR20120037772 A KR 20120037772A
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KR
South Korea
Prior art keywords
electron blocking
layer
light emitting
blocking layer
emitting device
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KR1020100099429A
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Korean (ko)
Inventor
박중서
이정식
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엘지이노텍 주식회사
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Priority to KR1020100099429A priority Critical patent/KR20120037772A/en
Publication of KR20120037772A publication Critical patent/KR20120037772A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/025—Physical imperfections, e.g. particular concentration or distribution of impurities
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/14—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a carrier transport control structure, e.g. highly-doped semiconductor layer or current-blocking structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/20—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
    • H01L33/24—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate of the light emitting region, e.g. non-planar junction
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of group III and group V of the periodic system
    • H01L33/32—Materials of the light emitting region containing only elements of group III and group V of the periodic system containing nitrogen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
    • H01L33/40—Materials therefor
    • H01L33/42—Transparent materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
    • H01L2933/0008—Processes
    • H01L2933/0033—Processes relating to semiconductor body packages
    • H01L2933/0058—Processes relating to semiconductor body packages relating to optical field-shaping elements

Abstract

PURPOSE: A light emitting device is provided to efficiently inject holes into an active layer by continuously increasing bandgap energy of an electron blocking layer along a thickness direction of the electron blocking layer. CONSTITUTION: A first conductive semiconductor layer(120) is formed on a substrate(110). An active layer(130) is formed on the first conductive semiconductor layer. An electron blocking layer(140) is formed on the active layer. A second conductive semiconductor layer(150) is formed on the electron blocking layer. The bandgap energy of the electron blocking layer continuously increases along the thickness direction of the electron blocking layer.

Description

Light Emitting Device

The embodiment relates to a light emitting device.

Light Emitting Device (LED) is a device that converts an electric signal into a form of light such as infrared rays, visible rays or ultraviolet rays by using the characteristics of a compound semiconductor, and is used for home appliances, remote controls, electronic displays, indicators, and various automation devices. It is used, and the use area of the light emitting device is gradually increasing.

As the use area of the light emitting device becomes wider as described above, the luminance required for electric light used for living, electric light for rescue signals, and the like is increased. Therefore, it is important to increase the light emission luminance of the light emitting device.

On the other hand, the emission luminance of the light emitting device is due to the recombination of the electron (Electrode) and the hole (Hall) bar, an electron blocking layer (Electron blocking layer) to prevent the separation of the electron can be used, the electron blocking layer Kink phenomenon in which the band gap energy is bent rapidly may occur at the interface between the electroblocking layer and the active layer, which may act as a barrier to holes.

Embodiments provide a light emitting device capable of increasing brightness by improving hole injection effects into an active layer.

The light emitting device according to the embodiment includes a first conductive semiconductor layer, an active layer on the first conductive semiconductor layer, an electron blocking layer on the active layer and a second conductive semiconductor layer on the electron blocking layer, wherein the bandgap energy of the electron blocking layer is It may increase continuously along the thickness direction of the barrier layer.

In addition, the electron blocking layer may have a composition of In x Al y Ga 1- x- y N (0 ≦ x ≦ 0.5, 0 ≦ y ≦ 0.5).

In addition, the composition of Al of In x Al y Ga 1- x- y N (0 ≦ x ≦ 0.5, 0 ≦ y ≦ 0.5) may increase continuously along the thickness direction of the electron blocking layer.

In addition, the bandgap energy of the electron blocking layer may increase in the shape of a parabola.

In addition, the bandgap energy at the top of the active layer and the bandgap energy at the bottom of the electron blocking layer may be the same.

In the light emitting device of the embodiment, as the bandgap energy of the electron blocking layer is continuously increased, light emission luminance of the light emitting device may be improved by effectively injecting holes into the active layer.

1 is a cross-sectional view showing a cross section of a light emitting device according to the embodiment;
2 and 3 are diagrams showing the concentration of electrons and holes according to the shape of the band gap energy of the electron blocking layer included in the light emitting device of FIG.
4 is a diagram illustrating an internal quantum efficiency of a light emitting device according to a shape of a band gap energy of the electron blocking layer of FIGS. 2 and 3;
FIG. 5 is a diagram illustrating an activation rate of p-type impurities according to Al composition change of the electron blocking layer included in the light emitting device of FIG. 1;
6 is a diagram illustrating an internal quantum efficiency according to an increase shape of a band gap energy of an electron blocking layer included in the light emitting device of FIG. 1;
7 is a cross-sectional view showing a light emitting device package according to the embodiment;
8 is a perspective view showing a lighting apparatus according to the embodiment,
9 is a cross-sectional view showing a section AA ′ of the lighting apparatus of FIG. 8;
10 is an exploded perspective view of a liquid crystal display according to an embodiment, and
11 is an exploded perspective view of a liquid crystal display according to an embodiment.

In the description of the embodiments, it is to be understood that each layer (film), region, pattern or structure is formed "on" or "under" a substrate, each layer The terms " on "and " under " encompass both being formed" directly "or" indirectly " In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

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

1 is a cross-sectional view showing a cross section of a light emitting device according to the embodiment, Figures 2 and 3 are a view showing the concentration of electrons and holes according to the shape of the band gap energy of the electron blocking layer included in the light emitting device of FIG. 4 is a diagram illustrating internal quantum efficiency of a light emitting device according to a shape of band gap energy of the electron blocking layer of FIGS. 2 and 3, and FIG. 5 is a change in Al composition of an electron blocking layer included in the light emitting device of FIG. 1. FIG. 6 is a diagram illustrating an activation rate of p-type impurities, and FIG. 6 is a diagram illustrating internal quantum efficiency of a band gap energy of an electron blocking layer included in the light emitting device of FIG. 1.

First, referring to FIG. 1, the light emitting device according to the embodiment includes a substrate 110, a first conductive semiconductor layer 120 on the substrate 110, an active layer 130 on the first conductive semiconductor layer 120, and an active layer ( 130 may include an electron blocking layer 140 and a second conductive semiconductor layer 150 on the electron blocking layer 140, and the band gap energy of the electron blocking layer 150 may be the thickness of the electron blocking layer 150. It can increase continuously along the direction.

The substrate 110 may be selected from the group consisting of sapphire (Al 2 O 3 ), GaN, SiC, ZnO, Si, GaP, InP, and GaAs, and the substrate 110 and the first conductive semiconductor layer 120. The buffer layer 112 may be formed therebetween to mitigate crystal defects due to lattice mismatch.

The buffer layer 112 may be formed of a combination of Group 3 and Group 5 elements, or may be formed of any one of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN, and a dopant may be doped.

An undoped semiconductor layer (not shown) may be formed on the substrate 110 or the buffer layer 112, and either or both of the buffer layer 112 and the undoped semiconductor layer (not shown) may or may not be formed. It may not be, but is not limited to this structure.

The first conductive semiconductor layer 120 is Si, Ge, is doped with n-type dopant, such as Sn, may be implemented as an n-type semiconductor layer, n-type semiconductor layer is for example, In x Al y Ga 1 -x- y It may be selected from a semiconductor material having a composition formula of N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1), for example, GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, or the like. .

The active layer 130 is a region where electrons and holes are recombined. The active layer 130 transitions to a low energy level as the electrons and holes recombine, and may generate light having a corresponding wavelength.

The active layer 130 may be formed of a single or multiple quantum well structure, a quantum-wire structure, or a quantum dot structure using a compound semiconductor material of Group 3 and Group 5 elements.

If the active layer 130 is formed of a quantum well structure, for example, the well having a composition formula of In x Al y Ga 1 -x- y N (0≤x≤1, 0 ≤y≤1, 0≤x + y≤1) Single quantum well structure or multiple quantum wells having a layer and a barrier layer having a compositional formula of In a Al b Ga 1 -a- b N ( 0≤a≤1, 0≤b≤1, 0≤a + b≤1) It may be formed of a structure (MQW: Multi Quantum Well). On the other hand, the well layer may be formed of a material having a band gap lower than the band gap of the barrier layer.

Therefore, more electrons are collected at the lower energy level of the quantum well layer, and as a result, the probability of recombination of electrons and holes can be increased, thereby improving the light emitting effect.

The electron blocking layer 140 may prevent the electrons injected into the active layer 130 from flowing out in the direction of the second conductive semiconductor layer 150.

2 and 3 illustrate concentrations of electrons and holes according to the shape of the band gap energy of the electron blocking layer 140.

FIG. 2 illustrates a case in which the band gap energy of the electron blocking layer 140 has a rectangular shape. Accordingly, a kink in which the band gap energy rapidly changes at an interface with the active layer 130 may occur. have. This acts as a barrier to holes, and as can be seen in FIG. 2, the concentration of holes at point A may be drastically lowered.

In contrast, FIG. 3 illustrates a case where the bandgap energy of the electron blocking layer 140 continuously increases along the thickness direction of the electron blocking layer 140. The balance of the interface between the active layer 130 and the electron blocking layer 140 is shown. It is possible to prevent the bandgap energy from changing discontinuously in the band.

That is, the bandgap energy at the top of the active layer 130 and the bandgap energy at the bottom of the electron blocking layer 140 may be the same.

Accordingly, as shown in B, the concentration of holes at the interface with the active layer 130 does not drop rapidly, and holes may be injected into the active layer 130 effectively.

Meanwhile, FIG. 3 illustrates that the bandgap energy of the electron blocking layer 140 is trapezoidal and increases linearly. However, the present invention is not limited thereto, and the bandgap energy of the electron blocking layer 140 is parabolic ( Parabolic, or increase with an exponential curve, the bandgap energy does not change rapidly at the interface between the electron blocking layer 140 and the active layer 130. Accordingly, the concentration of holes at the interface between the electron blocking layer 140 and the active layer 130 is not drastically reduced, and as a result, the efficiency of the light emitting device 100 may be improved by effectively injecting holes into the active layer 130.

4 is a road illustrating the internal quantum efficiency (IQE) of the light emitting device 100 according to the cases of FIGS. 2 and 3, and FIG. 3 shows that the internal quantum efficiency (IQE) is higher than that of FIG. 2. This is because, as described above, the electron blocking layer 140 has a bandgap energy that continuously increases in the thickness direction, thereby preventing kink phenomenon at the interface between the electron blocking layer 140 and the active layer 130. This is because holes can be injected into the active layer 130 effectively.

The electron blocking layer 140 may be formed of a semiconductor material having a composition of In x Al y Ga 1- x- y N (0 ≦ x ≦ 0.5, 0 ≦ y ≦ 0.5). On the other hand, the higher the composition of Al, the greater the bandgap energy, so that the composition of Al in the electron blocking layer 140 may gradually increase in the thickness direction.

5 is a diagram illustrating an activation rate of p-type impurities according to Al composition change of the electron blocking layer 140, and FIG. 6 is an internal quantum efficiency according to an increase shape of band gap energy of the electron blocking layer 140. Is a diagram showing.

Referring to FIG. 5, it can be seen that as the composition of the electron blocking layer 140 changes from left to right, the Al content increases, and thus the bandgap energy increases.

On the other hand, as can be seen in Figure 5 (a), the hole concentration decreases as the band gap energy increases, it can be seen that the resistance increases as can be seen in (b), which is the content of Al This is because the activation rate of the p-type impurity decreases with increasing.

Wherein the p-type impurity is Mg, and the concentration of Mg is the same at 2 x 10 19 cm -3 for all bandgap energy compositions.

Meanwhile, referring to FIG. 6, when the bandgap energy of the electron blocking layer 140 changes linearly (1), linearly (2) with changing slopes, parabolic (3), and exponential function (4), light emission accordingly The internal quantum efficiency of the device 100 is illustrated, and it can be seen that the efficiency is best when the band gap energy of the electron blocking layer 140 is increased with the shape of the parabolic 3.

That is, as described above, in all cases (1 to 4), the band gap energy is rapidly changed at the interface between the electron blocking layer 140 and the active layer 130 to prevent the kink effect serving as a barrier for holes. Thus, holes may be effectively injected into the active layer 130.

Among them, when the bandgap energy of the electron blocking layer 140 increases with the shape of the parabolic 3, holes can be injected into the active layer 130 more effectively by minimizing the decrease in the activation rate of the p-type impurity. have.

Meanwhile, the second conductive semiconductor layer 150 may be implemented as a p-type semiconductor layer to inject holes into the active layer 130. For example, the p-type semiconductor layer is a semiconductor material having a composition formula of In x Al y Ga 1 -x- y N (0≤x≤1, 0≤y≤1, 0≤x + y≤1), for example GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, or the like, and may be doped with p-type dopants such as Mg, Zn, Ca, Sr, and Ba.

In addition, a semiconductor layer having a polarity opposite to that of the second conductive semiconductor layer 150 may be formed on the second conductive semiconductor layer 150. In other words, when the second conductive semiconductor layer 150 is a P-type semiconductor layer, an N-type semiconductor layer may be further formed. In addition, the first conductive semiconductor layer 160 may be a P-type semiconductor layer, and the second conductive semiconductor layer 150 may be implemented as an N-type semiconductor layer. Accordingly, the light emitting device according to the first embodiment may include at least one of an N-P junction, a P-N junction, an N-P-N junction, and a P-N-P junction structure.

In addition, the first conductive semiconductor layer 120, the active layer 130, the electron blocking layer 140, and the second conductive semiconductor layer 150 may be formed by metal organic chemical vapor deposition (MOCVD) or chemical vapor deposition. (CVD; Chemical Vapor Deposition), Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), Sputtering It may be formed using a method such as, but is not limited thereto.

Referring back to FIG. 1, a transparent electrode layer 160 may be formed on the second conductive semiconductor layer 150, and an outer surface of the transparent electrode layer 160 may include a second electrode pad 152 made of nickel (Ni) or the like. Can be formed.

The transparent electrode layer 160 includes ITO, IZO (In-ZnO), GZO (Ga-ZnO), AZO (Al-ZnO), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), IrOx, RuOx, RuOx At least one of / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO may be formed to emit light generated in the active layer 130 to the outside. In addition, the current group phenomenon can be prevented by being formed on the entire outer surface of the second conductive semiconductor layer 150.

Meanwhile, one region of the first conductive semiconductor layer 120 may be exposed by mesa etching, and a first electrode pad 122 may be formed on the exposed upper surface of the first conductive semiconductor layer 120. That is, the first conductive semiconductor layer 120 includes an upper surface facing the active layer 130 and a lower surface facing the substrate 110, the upper surface includes an exposed region, and the first electrode pad 122 exposes the upper surface. Can be placed in the area.

The above-described embodiment has been described with reference to a light emitting device having a horizontal structure, but is not limited thereto and may be applied to a flip chip type or vertical structure.

7 is a cross-sectional view showing a cross section of a light emitting device package according to the embodiment.

Referring to FIG. 7, the light emitting device package 200 according to the embodiment includes a body 210 in which a cavity is formed, a light source unit 220 mounted on a bottom surface of the body 210, and an encapsulant 230 filled in a cavity. The encapsulant 230 may include the phosphor 240.

The body 210 is made of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photosensitive glass (PSG), polyamide 9T (PA9T) ), Neogeotactic polystyrene (SPS), a metal material, sapphire (Al 2 O 3 ), beryllium oxide (BeO), a printed circuit board (PCB, Printed Circuit Board) may be formed of at least one. The body 210 may be formed by injection molding, etching, or the like, but is not limited thereto.

The inner surface of the body 210 may be formed inclined surface. The angle of reflection of the light emitted from the light source unit 220 may vary according to the angle of the inclined surface, thereby adjusting the directing angle of the light emitted to the outside.

The shape of the cavity formed in the body 210 as viewed from above may be circular, rectangular, polygonal, elliptical, or the like, and in particular, the corner may be curved, but is not limited thereto.

The light source unit 220 may be mounted on the bottom surface of the body 210. For example, the light source unit 220 may be a light emitting device illustrated and described with reference to FIGS. 1 to 5. The light emitting device may be, for example, a colored light emitting device emitting light of red, green, blue, white, or the like, or an ultraviolet (Ultra Violet) light emitting device emitting ultraviolet light, but is not limited thereto. In addition, one or more light emitting devices may be mounted.

The light emitting device includes an electron blocking layer in which the band gap energy continuously increases along the thickness direction, as described above with reference to FIGS. 1 to 6, whereby the band gap energy at the interface between the active layer and the electron blocking layer is discontinuously changed. (Kink) can prevent the phenomenon. Accordingly, the concentration of holes at the interface with the active layer does not drop rapidly, and holes are effectively injected into the active layer, thereby improving efficiency of the light emitting device.

Meanwhile, the body 210 may include a first electrode 252 and a second electrode 254. The first electrode 252 and the second electrode 254 may be electrically connected to the light source unit 220 to supply power to the light source unit 220.

The first electrode 252 and the second electrode 254 are electrically separated from each other, and may reflect light generated from the light source unit 220 to increase light efficiency, and also externally generate heat generated from the light source unit 220. Can be discharged.

The first electrode 252 and the second electrode 254 are made of a metal material, for example, titanium (Ti), copper (Cu), nickel (Ni), gold (Au), chromium (Cr), and tantalum ( Ta, platinum (Pt), tin (Sn), silver (Ag), phosphorus (P), aluminum (Al), indium (In), palladium (Pd), cobalt (Co), silicon (Si), germanium ( Ge), hafnium (Hf), ruthenium (Ru), iron (Fe) may include one or more materials or alloys. In addition, the first electrode 252 and the second electrode 254 may be formed to have a single layer or a multilayer structure, but is not limited thereto.

The encapsulant 230 may be filled in the cavity and may include the phosphor 240. The encapsulant 230 may be formed of transparent silicone, epoxy, and other resin materials, and may be formed by filling in a cavity and then ultraviolet or thermal curing.

The phosphor 240 may be selected according to the wavelength of light emitted from the light source unit 220 so that the light emitting device package 200 may implement white light.

The phosphor 240 included in the encapsulant 230 may be a blue light emitting phosphor, a cyan light emitting phosphor, a green light emitting phosphor, a yellow green light emitting phosphor, a yellow light emitting phosphor, a yellow red light emitting phosphor, according to a wavelength of light emitted from the light source 220. One of an orange light emitting phosphor and a red light emitting phosphor may be applied.

That is, the phosphor 240 may be excited by the light having the first light emitted from the light source unit 220 to generate the second light. For example, when the light source unit 220 is a blue light emitting diode and the phosphor 240 is a yellow phosphor, the yellow phosphor may be excited by blue light to emit yellow light, and blue light and blue light generated from the blue light emitting diode As the yellow light generated by excitation is mixed, the light emitting device package 200 may provide white light.

Similarly, when the light source unit 220 is a green light emitting diode, a magenta phosphor or a blue and red phosphor 240 is mixed. When the light source unit 220 is a red light emitting diode, a cyan phosphor or a blue and green phosphor is used. For example, the case of mixing.

The phosphor 240 may be a known one such as YAG, TAG, sulfide, silicate, aluminate, nitride, carbide, nitridosilicate, borate, fluoride, or phosphate.

FIG. 8 is a perspective view illustrating a lighting device including a light emitting device module according to an embodiment, and FIG. 9 is a cross-sectional view taken along line AA ′ of the lighting device of FIG. 8.

Hereinafter, in order to describe the shape of the lighting apparatus 300 according to the embodiment in more detail, the longitudinal direction (Z) of the lighting apparatus 300, the horizontal direction (Y) perpendicular to the longitudinal direction (Z), and the length The height direction X perpendicular to the direction Z and the horizontal direction Y will be described.

That is, FIG. 9 is a cross-sectional view of the lighting apparatus 300 of FIG. 8 cut in the plane of the longitudinal direction Z and the height direction X, and viewed in the horizontal direction Y. FIG.

8 and 9, the lighting device 300 may include a body 310, a cover 330 fastened to the body 310, and a closing cap 350 positioned at both ends of the body 310. have.

The lower surface of the body 310 is fastened to the light emitting device module 340, the body 310 is conductive so that the heat generated from the light emitting device module 340 can be discharged to the outside through the upper surface of the body 310 And it may be formed of a metal material having an excellent heat dissipation effect.

The light emitting device module 340 may include a PCB substrate 342 and a light emitting device package 344. The light emitting device package 344 may be mounted on the PCB substrate 342 in multiple colors and in multiple rows to form an array. They may be mounted at equal intervals or may be mounted with various separation distances as necessary to adjust brightness. The PCB substrate 342 may be a MCPCB (Metal Core PCB) or a PCB made of FR4.

Meanwhile, as described above with reference to FIGS. 1 to 6, the light emitting device included in the light emitting device package 344 includes an electron blocking layer in which the bandgap energy continuously increases along the thickness direction, thereby preventing the active layer and the electron blocking layer. It is possible to prevent the kink phenomenon in which the band gap energy of the interface is changed discontinuously. Accordingly, the concentration of holes at the interface with the active layer does not drop rapidly, and holes are effectively injected into the active layer, thereby improving efficiency of the light emitting device.

The cover 330 may be formed in a circular shape to surround the lower surface of the body 310, but is not limited thereto.

The cover 330 protects the light emitting device module 340 from the outside and the like. In addition, the cover 330 may include diffusing particles to prevent glare of the light generated from the light emitting device package 344, and to uniformly emit light to the outside, and at least of the inner and outer surfaces of the cover 330 A prism pattern or the like may be formed on either side. In addition, a phosphor may be applied to at least one of an inner surface and an outer surface of the cover 330.

On the other hand, since the light generated from the light emitting device package 344 is emitted to the outside through the cover 330, the cover 330 should have excellent light transmittance, and has sufficient heat resistance to withstand the heat generated by the light emitting device package 344. The cover 330 is preferably formed of a material including polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), or the like. .

Closing cap 350 is located at both ends of the body 310 may be used for sealing the power supply (not shown). In addition, the closing cap 350 is formed with a power pin 352, the lighting device 300 according to the embodiment can be used immediately without a separate device to the terminal from which the existing fluorescent lamps are removed.

10 is an exploded perspective view of a liquid crystal display according to an embodiment.

FIG. 10 illustrates an edge-light method, and the liquid crystal display device 400 may include a liquid crystal display panel 410 and a backlight unit 470 for providing light to the liquid crystal display panel 410.

The liquid crystal display panel 410 may display an image using light provided from the backlight unit 470. The liquid crystal display panel 410 may include a color filter substrate 412 and a thin film transistor substrate 414 facing each other with the liquid crystal interposed therebetween.

The color filter substrate 412 may implement a color of an image displayed through the liquid crystal display panel 410.

The thin film transistor substrate 414 is electrically connected to the printed circuit board 418 on which a plurality of circuit components are mounted through the driving film 417. The thin film transistor substrate 414 may apply a driving voltage provided from the printed circuit board 418 to the liquid crystal in response to a driving signal provided from the printed circuit board 418.

The thin film transistor substrate 414 may include a thin film transistor and a pixel electrode formed of a thin film on another substrate of a transparent material such as glass or plastic.

The backlight unit 470 may convert the light provided from the light emitting device module 420, the light emitting device module 420 into a surface light source, and provide the light guide plate 430 to the liquid crystal display panel 410. Reflective sheet reflecting the light emitted to the light guide plate 430 to the plurality of films 450, 466, 464 and the light guide plate 430 to uniform the luminance distribution of the light provided from the light source 430 and to improve vertical incidence ( 440).

The light emitting device module 420 may include a PCB substrate 322 such that a plurality of light emitting device packages 424 and a plurality of light emitting device packages 424 are mounted to form an array.

Meanwhile, as described above with reference to FIGS. 1 to 6, the light emitting device included in the light emitting device package 424 includes an electron blocking layer in which the bandgap energy continuously increases along the thickness direction, thereby preventing the active layer and the electron blocking layer. It is possible to prevent the kink phenomenon in which the band gap energy of the interface is changed discontinuously. Accordingly, the concentration of holes at the interface with the active layer does not drop rapidly, and holes are effectively injected into the active layer, thereby improving efficiency of the light emitting device.

On the other hand, the backlight unit 470 is a diffusion film 466 for diffusing light incident from the light guide plate 430 toward the liquid crystal display panel 410, and a prism film 450 for condensing the diffused light to improve vertical incidence. It may be configured as), and may include a protective film 464 for protecting the prism film 450.

11 is an exploded perspective view of a liquid crystal display according to an embodiment.

However, the parts shown and described in FIG. 10 will not be repeatedly described in detail.

11 is a direct view, the liquid crystal display 500 may include a liquid crystal display panel 510 and a backlight unit 570 for providing light to the liquid crystal display panel 510.

Since the liquid crystal display panel 510 is the same as that described with reference to FIG. 10, detailed description thereof will be omitted.

The backlight unit 570 includes a plurality of light emitting device modules 523, a reflective sheet 524, a lower chassis 530 in which the light emitting device modules 523 and the reflective sheet 524 are accommodated, and an upper portion of the light emitting device module 523. It may include a diffusion plate 540 and a plurality of optical film 560 disposed in the.

Light emitting device module 523 A plurality of light emitting device packages 522 and a plurality of light emitting device packages 522 may be mounted to include a PCB substrate 521 to form an array.

Meanwhile, as described above with reference to FIGS. 1 to 6, the light emitting device included in the light emitting device package 522 includes an electron blocking layer in which the bandgap energy continuously increases along the thickness direction, thereby preventing the active layer and the electron blocking layer. It is possible to prevent the kink phenomenon in which the band gap energy of the interface is changed discontinuously. Accordingly, the concentration of holes at the interface with the active layer does not drop rapidly, and holes are effectively injected into the active layer, thereby improving efficiency of the light emitting device.

The reflective sheet 524 reflects the light generated from the light emitting device package 522 in the direction in which the liquid crystal display panel 510 is located to improve light utilization efficiency.

Meanwhile, the light generated by the light emitting device module 523 is incident on the diffusion plate 540, and the optical film 560 is disposed on the diffusion plate 540. The optical film 560 may include a diffusion film 566, a prism film 550, and a protective film 564.

The above embodiments are not limited to the configuration and method of the embodiments described as described above, but the embodiments may be configured by selectively combining all or part of the embodiments so that various modifications may be made. It may be.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It should be understood that various modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

100 light emitting element 110 substrate
112: buffer layer 120: first conductive semiconductor layer
122: first electrode pad 130: active layer
140: electron blocking layer 150: second conductive semiconductor layer
152: second electrode pad 160: light transmitting electrode layer

Claims (11)

A first conductive semiconductor layer;
An active layer on the first conductive semiconductor layer;
An electron blocking layer on the active layer; And
A second conductive semiconductor layer on the electron blocking layer;
The band gap energy of the electron blocking layer continuously increases along the thickness direction of the electron blocking layer. The method of claim 1,
The electron blocking layer has a composition of In x Al y Ga 1- x- y N (0 ≦ x ≦ 0.5, 0 ≦ y ≦ 0.5). The method of claim 2,
The composition of Al of In x Al y Ga 1- x- y N (0 ≦ x ≦ 0.5, 0 ≦ y ≦ 0.5) continuously increases along the thickness direction of the electron blocking layer. The method of claim 1,
The band gap energy of the electron blocking layer increases in the shape of a parabola. The method of claim 1,
And a band gap energy at an uppermost end of the active layer and a band gap energy at a lower end of the electron blocking layer. The method of claim 1,
A light emitting device comprising a first electrode pad exposed at a portion of an upper surface of the first conductive semiconductor layer and positioned on the exposed upper surface. The method of claim 1,
A translucent electrode layer on the second conductive semiconductor layer;
A light emitting device comprising a second electrode pad positioned on the transparent electrode layer. Board;
A first conductive semiconductor layer on the substrate;
An active layer on the first conductive semiconductor layer;
An electron blocking layer on the active layer; And
A second conductive semiconductor layer on the electron blocking layer;
The electron blocking layer is In x Al y Ga 1 -x- y N having the composition of (0≤x≤0.5, 0≤y≤0.5), the In x Al y Ga 1 -x- y N (0≤x≤ 0.5, 0≤y≤0.5) The composition of Al increases along the thickness direction of the electron blocking layer. The method of claim 8,
And a band gap energy at an uppermost end of the active layer and a band gap energy at a lower end of the electron blocking layer. The method of claim 8,
The band gap energy of the electron blocking layer continuously increases along the thickness direction of the electron blocking layer. The method of claim 10,
The band gap energy of the electron blocking layer increases in the shape of a parabola.
KR1020100099429A 2010-10-12 2010-10-12 Light emitting device KR20120037772A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20130129683A (en) * 2012-05-21 2013-11-29 포항공과대학교 산학협력단 Semiconductor light emitting device having graded superlattice electron blocking layer
KR101414654B1 (en) * 2012-06-08 2014-07-03 엘지전자 주식회사 Nitride semiconductor light emitting device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20130129683A (en) * 2012-05-21 2013-11-29 포항공과대학교 산학협력단 Semiconductor light emitting device having graded superlattice electron blocking layer
KR101414654B1 (en) * 2012-06-08 2014-07-03 엘지전자 주식회사 Nitride semiconductor light emitting device

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