KR101861635B1 - Light emitting device amd light emitting device package including the same - Google Patents

Abstract

The embodiment includes a first conductivity type semiconductor layer; An active layer disposed on the first conductive semiconductor layer; An undoped semiconductor layer disposed on the active layer and having irregularities formed on the surface thereof; And a second conductive type semiconductor layer disposed on the undoped semiconductor layer and having concave and convex portions formed on the surface thereof.

Description

[0001] The present invention relates to a light emitting device and a light emitting device package including the light emitting device.

Embodiments provide a light emitting device and a light emitting device package including the same.

BACKGROUND ART Light emitting devices such as a light emitting diode (LD) or a laser diode using semiconductor materials of Group 3-5 or 2-6 group semiconductors are widely used for various colors such as red, green, blue, and ultraviolet And it is possible to realize white light rays with high efficiency by using fluorescent materials or colors, and it is possible to realize low energy consumption, semi-permanent life time, quick response speed, safety and environment friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps .

Therefore, a transmission module of the optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, a white light emitting element capable of replacing a fluorescent lamp or an incandescent lamp Diode lighting, automotive headlights, and traffic lights.

In the light emitting device, electrons injected through the first conductive type semiconductor layer and holes injected through the second conductive type semiconductor layer meet each other to emit light having energy determined by a specific energy band of the material forming the active layer (light emitting layer) do. In the light emitting device package, the phosphor is excited by the light emitted from the light emitting device to emit light in a longer wavelength range than the light emitted from the active layer.

Light emitted from the active layer can be emitted to the outside of the light emitting structure through the second conductivity type semiconductor layer. At this time, some light may be totally reflected due to a difference in refractive index between the light emitting structure and the outside, or the path of light emitted to the outside may not be uniform.

That is, when light generated in the active layer exits to the outside, a total reflection condition occurs due to a difference in refractive index between the light emitting structure, which is a nitride semiconductor material, and the outside, so that light incident at an angle greater than a critical angle of total reflection can not escape to the outside The light is reflected back to the inside of the device and consumed, thereby deteriorating the light extraction efficiency.

In order to solve such a problem, there is an attempt to form irregularities on the surface of the light emitting structure, particularly the second conductivity type semiconductor layer. However, if unevenness is formed on the surface of the light emitting structure by a method such as selective etching, the quality of the light emitting structure which is a nitride semiconductor may be deteriorated. Irregular irregularities may be formed on the surface due to irregular growth of the nitride semiconductor if the growth temperature is increased, but the light emitting structure including the active layer may be particularly deteriorated at high temperature growth. In addition, the additional etching process complicates the manufacturing process and takes a long time to manufacture.

The embodiment attempts to provide a light emitting device which is excellent in light extraction efficiency and in which the quality of the light emitting structure is not deteriorated.

The embodiment includes a first conductivity type semiconductor layer; An active layer disposed on the first conductive semiconductor layer; An undoped semiconductor layer disposed on the active layer and having irregularities formed on the surface thereof; And a second conductive type semiconductor layer disposed on the undoped semiconductor layer and having concave and convex portions formed on the surface thereof.

The unevenness of the surface of the second conductivity type semiconductor layer may be the same as the unevenness and the pattern of the surface of the undoped semiconductor layer.

The height of the unevenness of the surface of the second conductivity type semiconductor layer may be smaller than the height of the unevenness of the surface of the undoped semiconductor layer.

The thickness of the undoped semiconductor layer is 2.5 to 5 nanometers, and the height of the unevenness in the undoped semiconductor layer may be 0.5 to 1 micrometer.

The thickness of the second conductivity type semiconductor layer may be 90 to 110 nanometers, and the height of the concavities and convexities in the second conductivity type semiconductor layer may be 0.4 to 0.8 micrometers.

The shape of the irregularities may be at least one of a cone, a pyramid and a polygonal horn.

Another embodiment includes a first lead frame and a second lead frame; The above-described light emitting device electrically connected to the first lead frame and the second lead frame, respectively; And a phosphor layer that is excited by light of a first wavelength range emitted from the light emitting device to emit light of a second wavelength range.

According to the embodiment, irregularities on the surface of the light emitting structure in the light emitting device, that is, irregularities on the surface of the second conductivity type semiconductor layer are naturally grown along the surface of the undoped semiconductor layer, Can be improved.

1 is a view illustrating an embodiment of a light emitting device,
FIG. 2 is an enlarged view of 'A' in FIG. 1,
3 is a view showing another embodiment of the light emitting device,
4 to 8 are views showing a method of manufacturing the light emitting device of FIG. 1,
FIG. 9 is a view showing the operation of the light emitting device of FIG. 1,
10 is a view showing another embodiment of the light emitting device,
11 is a view illustrating an embodiment of a light emitting device package including a light emitting device,
12 is a view showing an embodiment of a headlamp including a light emitting device package,
13 is a view showing an embodiment of a video display device including a light emitting device package.

In the description of the embodiment according to the present invention, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram showing a first embodiment of the present invention; Fig.

FIG. 1 is a view showing an embodiment of a light emitting device, and FIG. 2 is an enlarged view of 'A' in FIG.

The light emitting device 100 of FIG. 1 includes a substrate 110, a buffer layer 120, a light emitting structure and an undoped semiconductor layer 150, a first electrode 180 and a second electrode 185 .

The substrate 110 may be formed of a carrier wafer, a material suitable for semiconductor material growth. May be formed of a highly thermally conductive material, includes a conductive substrate or an insulating substrate such as sapphire (Al ₂ O _3), SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, Ge and Ga ₂ 0 ₃ can be used.

The buffer layer 120 is intended to alleviate the difference in lattice mismatch and thermal expansion coefficient of the material between the substrate 110 and the light emitting structure. The material of the buffer layer 120 may be at least one of Group III-V compound semiconductor such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN.

The light emitting structure includes a first conductive semiconductor layer 132, an active layer 134, and a second conductive semiconductor layer 136. Since a portion of the first conductive semiconductor layer 132 is mesa-etched, electrodes such as a sapphire substrate can not be formed under the insulating substrate. Therefore, the first electrode 180 is disposed in the etched region .

The first conductive semiconductor layer 132 may be formed of a semiconductor compound. Group 3-Group 5, Group 2-Group 6, and the like, and the first conductive type dopant may be doped. When the first conductivity type semiconductor layer 132 is an n-type semiconductor layer, the first conductivity type dopant may include Si, Ge, Sn, Se, and Te as an n-type dopant.

The first conductive semiconductor layer 132 includes a semiconductor material having a composition formula of Al _x In _y Ga _(1-xy) N (0? X? 1, 0? _Y? 1, 0? _X + y? 1) can do. The first conductive semiconductor layer 132 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP and InP.

Electrons injected through the first conductivity-type semiconductor layer 132 and holes injected through the second conductivity-type semiconductor layer 136, which are formed later, are in contact with each other to form an active layer 134, It is a layer that emits light with energy determined by the band.

The active layer 134 may be formed of a material selected from the group consisting of a double heterojunction structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure Or at least one of them may be formed. For example, the active layer 120 may be formed with multiple quantum well structures by injecting trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) But is not limited thereto.

The well layer / barrier layer of the active layer 134 may be formed of any one of InGaN / GaN, InGaN / InGaN, GaN / AlGaN, InAlGaN / GaN, InAlGaN / InAlGaN, GaAs (InGaAs) / AlGaAs, GaP But it is not limited thereto. The well layer may be formed of a material having a band gap lower than the band gap of the barrier layer.

A conductive clad layer (not shown) may be formed on and / or below the active layer 134. The conductive cladding layer may be formed of a semiconductor having a band gap wider than the barrier layer or the band gap of the active layer 134. For example, the conductive clad layer may include GaN, AlGaN, InAlGaN, superlattice structure, or the like. Further, the conductive clad layer may be doped with n-type or p-type.

On the active layer 134, an undoped semiconductor layer 150 and a second conductivity type semiconductor layer 136 are disposed. The undoped semiconductor layer 150 has irregularities formed on the surface thereof and concave and convex portions are formed on the surface of the second conductivity type semiconductor layer 136 in accordance with the irregularities on the surface of the undoped semiconductor layer 150.

The irregularities on the surface of the undoped semiconductor layer 150 and the irregularities on the surface of the second conductivity type semiconductor layer 136 may be formed in the same pattern, which is formed according to a manufacturing method described later.

The thickness t of the undoped semiconductor layer 150 may be 2.5 to 5 nanometers and the height h of the unevenness in the undoped semiconductor layer 150 may be 0.5 to 1 micrometer. May be twice the height (h) of the unevenness. Here, the thickness t means the thickness of the undoped semiconductor layer 150 in the portion where the unevenness is not formed, and the shape of the unevenness may be a cone, a pyramid and a polygonal horn, If this circle is a circle, it means diameter. If the cross-section is polygonal, it means the length of the side.

The thickness of the second conductivity type semiconductor layer 136 may be 90 to 110 nm, and the height of the irregularities in the second conductivity type semiconductor layer 136 may be 0.4 to 0.8 micrometer. The height of the concave and convex in the second conductivity type semiconductor layer 136 is not less than 80% of the height of the concave and convex in the undoped semiconductor layer 150, Respectively.

The undoped semiconductor layer 150 may be formed of a nitride semiconductor layer such as InAlGaN or AlGaN. Unlike the first and second conductivity-type semiconductor layers 132 and 136, the undoped semiconductor layer 150 does not include a dopant.

The second conductive semiconductor layer 136 may be formed of a semiconductor compound. 3-group-5, group-2-group-6, and the like, and the second conductivity type dopant may be doped. For example, it may include 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? When the second conductive semiconductor layer 136 is a p-type semiconductor layer, the second conductive dopant may include Mg, Zn, Ca, Sr, and Ba as p-type dopants.

The first and second electrodes 180 and 185 may include at least one of aluminum (Al), titanium (Ti), chrome (Cr), nickel (Ni), copper (Cu), and gold As shown in FIG.

In this embodiment, the first conductivity type semiconductor layer 132 may be a p-type semiconductor layer, and the second conductivity type semiconductor layer 136 may be an n-type semiconductor layer. Further, on the second conductivity type semiconductor layer 136, a semiconductor layer including an n-type or p-type semiconductor layer may be further formed. Accordingly, the light emitting structure may have any one of np, pn, npn, and pnp junction structures.

The light emitting device 100 according to the embodiment has a structure in which irregularities on the surface of the light emitting structure, that is, irregularities on the surface of the second conductivity type semiconductor layer 136 are naturally grown along the surface of the undoped semiconductor layer 150, The light extraction efficiency on the surface of the light emitting structure can be improved.

3 is a view showing another embodiment of the light emitting device. 1, an electron blocking layer 140 is disposed between the active layer 134 and the undoped semiconductor layer 150. The electron blocking layer 140 is formed on the active layer 134 and the undoped semiconductor layer 150, have. The electron blocking layer 140 may be formed of a semiconductor containing nitrogen and may include AlGaN. The electron blocking layer 140 may be formed of AlGaN in the direction of the undoped semiconductor layer 150 and the second conductivity type semiconductor layer 136 from the active layer 134 It is possible to prevent electrons from moving. In this embodiment, the first conductivity type semiconductor layer 132 may be an n-type semiconductor layer, and the second conductivity type semiconductor layer 136 may be a p-type semiconductor layer.

4 to 8 are views showing a method of manufacturing the light emitting device of FIG.

4, a buffer layer 120, a first conductivity type semiconductor layer 132, and an active layer 134 are grown on a substrate 110.

The light emitting structure 130 including the first conductivity type semiconductor layer 132, the active layer 134 and the second conductivity type semiconductor layer 136 to be described later may be formed, for example, by metal organic chemical vapor deposition (MOCVD) (CVD), a plasma enhanced chemical vapor deposition (PECVD), a molecular beam epitaxy (MBE), a hydride vapor phase epitaxy (HVPE) ), And the like, but the present invention is not limited thereto.

The substrate 110 may be formed of a carrier wafer, a material suitable for semiconductor material growth. Or may be formed of a material having excellent thermal conductivity, and may include a conductive substrate or an insulating substrate. For example, at least one of sapphire (Al ₂ O ₃ ), SiC, GaAs, GaN, ZnO, Si, GaP, InP, Ge, and Ga ₂ O ₃ can be used. A concave-convex structure may be formed on the substrate 110, but the present invention is not limited thereto. The substrate 110 may be wet-cleaned to remove impurities on the surface.

A buffer layer 120 may be grown between the first conductive semiconductor layer 132 and the substrate 110 to mitigate the difference in lattice mismatch and thermal expansion coefficient of the material. The material of the buffer layer 120 is as described in FIG.

The composition of the first conductivity type semiconductor layer 132 is the same as that described above and the composition of the first conductivity type semiconductor layer 132 is the same as that of the first conductivity type semiconductor layer 132 by using a chemical vapor deposition method (CVD) A GaN layer can be formed. The first conductivity type semiconductor layer 132 is formed by depositing a silane gas containing an n-type impurity such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ) (SiH ₄ ) may be implanted.

The composition of the active layer 134 is the same as described above. For example, the trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas A well structure may be formed, but is not limited thereto.

Then, the undoped semiconductor layer 150 is grown on the active layer 134 as shown in FIG. The composition of the undoped semiconductor layer 150 is as described above and can be grown by chemical vapor deposition (CVD) or molecular beam epitaxy (MBE), sputtering, or vapor phase epitaxy (HVPE). The light emitting structure including the undoped semiconductor layer 150 can be grown at a temperature of 950 캜 to 1050 캜.

As shown in FIG. 6, unevenness is formed on the surface of the undoped semiconductor layer 150. For example, when hydrogen and nitrogen are injected into the chamber, hydrogen and / or nitrogen gas collide with the surface of the undoped semiconductor layer 150 to form recesses and protrusions on the surface of the undoped semiconductor layer 150, Can be formed. Alternatively, the surface of the undoped semiconductor layer 150 may be selectively etched to form irregularities, but the present invention is not limited thereto.

After the irregularities are formed on the surface of the undoped semiconductor layer 150 as described above, the second conductivity type semiconductor layer 136 is grown on the surface of the undoped semiconductor layer 150 as shown in FIG. The composition of the second conductivity type semiconductor layer 136 is the same as that described above. The composition of the second conductivity type semiconductor layer 136 is the same as that described above, and a p-type semiconductor such as trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and magnesium Bisei including impurities butyl cyclopentadienyl magnesium _{(EtCp 2 Mg) {Mg (} C 2 H 5 C 5 H 4) 2} is injected may be a p-type GaN layer formed, but the embodiment is not limited thereto.

At this time, the second conductive semiconductor layer 136 is formed to have a concavo-convex structure according to the concavo-convex shape of the surface of the undoped semiconductor layer 150. When the second conductivity type semiconductor layer 136 is grown in the process chamber, the height of the concave and convex in the second conductivity type semiconductor layer 136 may be smaller than the height of the concave and the convex on the surface of the undoped semiconductor layer 150, This is because the material constituting the second conductivity type semiconductor layer 136 can be grown by first filling the depressed portion of the unevenness on the surface of the undoped semiconductor layer 150.

8, the undoped semiconductor layer 150, the active layer 134, and a part of the first conductivity type semiconductor layer 132 are mesa-etched from the second conductivity type semiconductor layer 136, Thereby securing a space to be formed.

When the first and second electrodes are formed on the structure shown in FIG. 8, the horizontal light emitting device shown in FIG. 1 is completed.

9 is a view showing the operation of the light emitting device of FIG. The light emitting device 100 may have a structure in which irregularities are formed on the surface of the undoped semiconductor layer 150 and the second conductive semiconductor layer 136 is also formed in the same pattern according to the irregularities on the surface of the undoped semiconductor layer 150 So that irregularities are formed. Therefore, among the light emitted from the active layer 134, light traveling in the direction of the undoped semiconductor layer 150 is refracted at the interface between the undoped semiconductor layer 150 and the second conductivity type semiconductor layer 136, The light extraction efficiency of the entire light emitting device 100 can be improved by refracting the conductive semiconductor layer 136 from the light emitting device 100 to the outside. The unevenness of the surface of the second conductivity type semiconductor layer 136 is naturally patterned according to the shape of the undoped semiconductor layer 150, so that the quality thereof is not deteriorated.

10 is a view showing another embodiment of the light emitting device, which shows a vertical light emitting device.

The light emitting device 200 according to the embodiment includes the bonding layer 270, the reflection layer 265, the ohmic layer 260, the light emitting structure 230, and the undoped semiconductor layer 250 on the conductive supporting substrate 275 .

Since the conductive supporting substrate 275 can serve as the second electrode, a metal having excellent electrical conductivity can be used and a metal having a high thermal conductivity can be used since heat generated during operation of the light emitting device can be sufficiently radiated.

The conductive support substrate 275 may be made of a material selected from the group consisting of molybdenum (Mo), silicon (Si), tungsten (W), copper (Cu), and aluminum (Al) gold (Au), copper alloy (Cu alloy), nickel (Ni), copper-tungsten (Cu-W), carrier wafer (for example: GaN, Si, Ge, GaAs , ZnO, SiGe, SiC, SiGe, Ga 2 O _3, etc.), and the like.

In addition, the conductive supporting substrate 275 may have a mechanical strength enough to be separated into separate chips through a scribing process and a breaking process without causing warping of the entire nitride semiconductor have.

The bonding layer 270 may bond the reflective layer 265 to the conductive supporting substrate 275 and the reflective layer 265 may function as an adhesion layer. The bonding layer is formed from a group consisting of (Au), Sn, In, Al, Si, Ag, Ni and Cu. The material to be selected or an alloy thereof.

The reflective layer 265 may be about 2500 Angstroms thick. The reflective layer 265 may be formed of a metal layer containing aluminum (Al), silver (Ag), nickel (Ni), platinum (Pt), rhodium (Rh), or an alloy containing Al, Ag, Pt, . Aluminum, silver, and the like can effectively reflect the light generated in the active layer 234, thereby greatly improving the light extraction efficiency of the light emitting device.

The ohmic characteristics of the light emitting structure 230, particularly, the second conductive semiconductor layer 236 may be low because of low impurity doping concentration and high contact resistance. Therefore, in order to improve the ohmic characteristics, the ohmic layer 260 A transparent electrode or the like can be formed.

The ohmic layer 260 may be disposed on the concavo-convex shape of the surface of the second conductivity type semiconductor layer 236 and may have a thickness of about 200 angstroms. The ohmic layer 260 may be formed of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide ), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO nitride), AGZO (Al- Ga ZnO), IGZO , NiO, RuOx / ITO, Ni / IrOx / Au, and Ni / IrOx / Au / ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Sn, In, Ru, Au, and Hf, and is not limited to such a material.

The structures of the light emitting structure 230 and the undoped semiconductor layer 250 are the same as those described in FIG. However, in this embodiment, the surface of the first conductivity type semiconductor layer 232 may have irregularities to improve the light extraction efficiency.

The unevenness of the surface of the undoped semiconductor layer 250 and the unevenness of the surface of the second conductivity type semiconductor layer 236 formed thereby increase the light extracting angle of light traveling to the lower portion of the light emitting device 200 So that the light extracting angle of the light reflected by the reflective layer 265 can also be increased.

A first electrode 280 is disposed on the first conductive semiconductor layer 232 and a passivation layer 290 may be formed on a side surface of the light emitting structure 230. The passivation layer 290 may be made of an insulating material, and the insulating material may be made of a non-conductive oxide or nitride. For example, the passivation layer 290 may include a silicon oxide (SiO ₂ ) layer, an oxynitride layer, .

11 is a view showing an embodiment of a light emitting device package including a light emitting device.

The light emitting device package 300 according to the embodiment includes a package body 310, a first lead frame 321 and a second lead frame 322 provided on the package body 310, The light emitting device 100 described above that is installed to be electrically connected to the first lead frame 321 and the second lead frame 322 and the molding part 350 that covers the surface or the side surface of the light emitting device 100 .

The package body 310 may be formed of a silicon material, a synthetic resin material, or a metal material. A sloped surface may be formed around the light emitting device 100 to increase light extraction efficiency.

The first lead frame 321 and the second lead frame 322 are electrically separated from each other and provide power to the light emitting device 100. [ The first lead frame 321 and the second lead frame 322 may increase the light efficiency by reflecting the light generated from the light emitting device 100. The heat generated from the light emitting device 100 To the outside.

The light emitting device 100 may be a horizontal light emitting device or a vertical light emitting device and may be mounted on the package body 310 or installed on the first lead frame 321 or the second lead frame 322 . The light emitting device 100 may be electrically connected to the first lead frame 321 and the second lead frame 322 by any one of wire, flip chip, and die bonding methods. In this embodiment, the light emitting device 100 is connected to the first lead frame 321 through the conductive adhesive layer 330, and the second lead frame 322 and the wires 340 are bonded.

The molding part 350 surrounds and protects the light emitting device 100. The phosphor 350 may be included in the molding part 350 to change the wavelength of the light emitted from the light emitting device 100.

In the light emitting device package 300 according to the embodiment, the light emitting device 100 disposed inside is naturally grown along the surface of the undoped semiconductor layer, that is, the unevenness of the surface of the light emitting structure, that is, the unevenness of the surface of the second conductivity type semiconductor layer The damage is small and the light extraction efficiency on the surface of the light emitting structure can be improved.

The light emitting device package 300 may be mounted on one or a plurality of light emitting devices according to the embodiments described above, but the present invention is not limited thereto.

A plurality of light emitting device packages according to embodiments may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, and the like may be disposed on the light path of the light emitting device package. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Still another embodiment may be implemented as a display device, an indicating device, a lighting system including the semiconductor light emitting device or the light emitting device package described in the above embodiments, for example, the lighting system may include a lamp, a streetlight . Hereinafter, a head lamp and a backlight unit will be described as an embodiment of an illumination system in which the above-described light emitting device package is disposed.

12 is a view showing an embodiment of a headlamp including a light emitting device package.

The light emitted from the light emitting device module 401 in which the light emitting device package is disposed is reflected by the reflector 402 and the shade 403 and then transmitted through the lens 404 to the front of the vehicle body You can head.

As described above, irregularities on the surface of the light emitting structure in the light emitting device used for the light emitting element module 401, that is, irregularities on the surface of the second conductivity type semiconductor layer are naturally grown along the surface of the undoped semiconductor layer, And light extraction efficiency on the surface of the light emitting structure can be improved.

13 is a view showing an embodiment of a video display device including a light emitting device package.

As shown in the drawing, the image display apparatus 500 according to the present embodiment includes a light source module, a reflection plate 520 on the bottom cover 510, and a reflection plate 520 disposed in front of the reflection plate 520, A first prism sheet 550 and a second prism sheet 560 disposed in front of the light guide plate 540 and a second prism sheet 560 disposed between the first prism sheet 560 and the second prism sheet 560, A panel 570 disposed in front of the panel 570 and a color filter 580 disposed in the front of the panel 570.

The light source module comprises a light emitting device package 535 on a circuit board 530. Here, the circuit board 530 may be a PCB or the like, and the light emitting device package 535 is the same as that described with reference to FIG.

The bottom cover 510 can house the components in the image display apparatus 500. The reflective plate 520 may be formed as a separate component as shown in the drawing, or may be provided on the rear surface of the light guide plate 540 or on the front surface of the bottom cover 510 with a highly reflective material.

The reflector 520 can be made of a material having a high reflectance and can be used in an ultra-thin shape, and a polyethylene terephthalate (PET) can be used.

The light guide plate 540 scatters the light emitted from the light emitting device package module so that the light is uniformly distributed over the entire screen area of the LCD. Accordingly, the light guide plate 530 is made of a material having a good refractive index and transmittance. The light guide plate 530 may be formed of poly methylmethacrylate (PMMA), polycarbonate (PC), or polyethylene (PE). Also, if the light guide plate 540 is omitted, an air guide display device can be realized.

The first prism sheet 550 is formed on one side of the support film with a translucent and elastic polymer material. The polymer may have a prism layer in which a plurality of steric structures are repeatedly formed. As shown in the drawings, the plurality of patterns may be repeatedly provided with a stripe pattern.

In the second prism sheet 560, a direction of a floor and a valley of one side of the supporting film may be perpendicular to a direction of a floor and a valley of one side of the supporting film in the first prism sheet 550. This is for evenly distributing the light transmitted from the light source module and the reflective sheet in all directions of the panel 570.

In this embodiment, the first prism sheet 550 and the second prism sheet 560 constitute an optical sheet, which may be made of other combinations, for example, a microlens array or a combination of a diffusion sheet and a microlens array Or a combination of one prism sheet and a microlens array, or the like.

The panel 570 may include a liquid crystal display (LCD) panel, and may include other types of display devices that require a light source in addition to the liquid crystal display panel.

In the panel 570, a liquid crystal is positioned between glass bodies, and a polarizing plate is placed on both glass bodies to utilize the polarization of light. Here, the liquid crystal has an intermediate property between a liquid and a solid, and liquid crystals, which are organic molecules having fluidity like a liquid, are regularly arranged like crystals. The liquid crystal has a structure in which the molecular arrangement is changed by an external electric field And displays an image.

A liquid crystal display panel used in a display device is an active matrix type, and a transistor is used as a switch for controlling a voltage supplied to each pixel.

A color filter 580 is provided on the front surface of the panel 570 so that only the red, green, and blue light is transmitted through the panel 570 for each pixel.

The irregularities on the surface of the light emitting structure in the light emitting device disposed in the image display device according to the present embodiment, that is, irregularities on the surface of the second conductivity type semiconductor layer are naturally grown along the surface of the undoped semiconductor layer, The light extraction efficiency on the surface of the light emitting structure can be improved.

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 will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

100, 200: light emitting device 120: buffer layer
132, 232: first conductivity type semiconductor layers 134, 234: active layer
136, and 236: a second conductivity type semiconductor layer 150, 250: an undoped semiconductor layer
140: electron blocking layer 180, 185: first and second electrodes
260: ohmic layer 265: reflective layer
270: bonding layer 275: conductive support substrate
300: light emitting device package 310: package body
321, 322: first and second lead frames 330: conductive adhesive layer
340: wire 350: molding part
360: phosphor 400: head lamp
410: light emitting device module 420: reflector
430: Shade 440: Lens
800: Display device 810: Bottom cover
820: reflector 830: circuit board module
840: light guide plate 850, 860: first and second prism sheets
870: Panel 880: Color filter

Claims (7)

A first conductivity type semiconductor layer in which a part of the region is etched;
An active layer disposed on the first conductive semiconductor layer;
An undoped semiconductor layer disposed on the active layer and having irregularities formed on the surface thereof;
A first electrode disposed on the etched region of the first conductive semiconductor layer;
A second conductivity type semiconductor layer disposed on the undoped semiconductor layer and having recesses and protrusions on the surface thereof; And
And a second electrode disposed on a part of the surface of the second conductivity type semiconductor layer,
The thickness of the undoped semiconductor layer is 2.5 to 5 nanometers, the height of the unevenness in the undoped semiconductor layer is 0.5 to 1 micrometer,
Wherein the thickness of the second conductivity type semiconductor layer is 90 to 110 nanometers, and the height of the concave and the convex in the second conductivity type semiconductor layer is 0.4 to 0.8 micrometers. The method according to claim 1,
Wherein the concavities and convexities on the surface of the second conductivity type semiconductor layer are the same as the concavities and convexities on the surface of the undoped semiconductor layer. delete delete delete The method according to claim 1,
Wherein the shape of the irregularities includes at least one of a cone, a pyramid and a polygonal horn. A first lead frame and a second lead frame;
A light emitting element according to any one of claims 1, 2, and 6 electrically connected to the first lead frame and the second lead frame, respectively; And
And a phosphor layer which is excited by the light of the first wavelength range emitted from the light emitting device and emits light of the second wavelength range.

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