KR20170010119A - Edge light emitting diode, surface light having the same and method for fabricating the same - Google Patents

Edge light emitting diode, surface light having the same and method for fabricating the same Download PDF

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KR20170010119A
KR20170010119A KR1020150097173A KR20150097173A KR20170010119A KR 20170010119 A KR20170010119 A KR 20170010119A KR 1020150097173 A KR1020150097173 A KR 1020150097173A KR 20150097173 A KR20150097173 A KR 20150097173A KR 20170010119 A KR20170010119 A KR 20170010119A
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South Korea
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light
substrate
emitting diode
light emitting
emitted
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KR1020150097173A
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Korean (ko)
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KR101731489B1 (en
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곽준섭
오승규
박현정
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순천대학교 산학협력단
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
    • F21K9/61—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction using light guides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/60—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction
    • F21K9/64—Optical arrangements integrated in the light source, e.g. for improving the colour rendering index or the light extraction using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F21K9/90—Methods of manufacture
    • 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
    • H01L33/10—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 light reflecting structure, e.g. semiconductor Bragg reflector
    • 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
    • H01L33/48—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 body packages
    • H01L33/50—Wavelength conversion elements
    • H01L33/501—Wavelength conversion elements characterised by the materials, e.g. binder
    • H01L33/502—Wavelength conversion materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2105/00—Planar light sources
    • F21Y2105/10—Planar light sources comprising a two-dimensional array of point-like light-generating elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]

Abstract

The present invention relates to an edge-type light-emitting diode, a surface light source comprising edge-type light-emitting diodes, and a method for manufacturing an edge-type light-emitting diode. More specifically, the present invention relates to an edge-type light-emitting diode in which efficiency of extraction of light in a lateral direction is improved, and also relates to a surface light source comprising edge-type light-emitting diodes and a method for manufacturing an edge-type light-emitting diode. An edge-type light-emitting diode according to an embodiment of the present invention comprises: a substrate on which first light extraction structures are formed on respective sides thereof; a first reflection layer which is formed on one surface of the substrate; a semiconductor stack structure which is formed on an opposite surface of the substrate facing the one surface of the substrate, and which includes an n-type semiconductor layer, an active layer, and a p-type semiconductor layer; and a second reflection layer which is formed on the semiconductor stack structure. In this case, light emitted from the active layer may be emitted through the sides of the substrate or sides of the semiconductor stack structure.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side light emitting diode (LED), a planar light source including the same,

The present invention relates to a side light emitting diode, a planar light source including the planar light source, and a method of manufacturing the same. More particularly, the present invention relates to a side light emitting diode with improved light extraction efficiency in a lateral direction, a planar light source including the planar light source, and a method of manufacturing the same.

A liquid crystal display (LCD) requiring a separate light source uses a plurality of fluorescent lamps such as a cold cathode fluorescent lamp (CCFL) and an external electrode fluorescent lamp (EEFL) as a light source Or a plurality of light emitting diodes (LEDs) are used. These light sources are provided in a backlight unit (BLU) such as a light guide plate, a plurality of optical sheets, and a reflection plate.

In particular, a semiconductor light emitting device such as a light emitting diode (LED) used as a light source by exchanging electricity by converting electricity into infrared rays or light using the characteristics of a compound semiconductor is widely used as a light source, a display device and a light source, It is possible to emit light of a desired wavelength with power and to suppress the emission of environmentally harmful substances such as mercury, and the development thereof is accelerating in consideration of energy saving and environmental protection aspects.

However, when a light emitting diode is used as a light source, light tends to concentrate and diverge into a narrow area. In order to apply this to a surface light source such as a display device, it is necessary to distribute the light evenly over a wide area.

The backlight unit (BLU) is roughly divided into an edge type and a direct type according to the position of the lamp relative to the display surface. Of these, the direct-type backlight unit is widely used in large-sized liquid crystal display devices because it has high light utilization rate, is easy to handle, and has no limitation on the size of the display surface.

A light emitting diode used in a direct-type backlight unit is divided into top emitting, bottom emitting or edge emitting according to the light emitting method. Due to the light efficiency of the light emitting diode, A bottom emission scheme is generally used. However, the light emitting diode backlight unit of the upper emission type or the lower emission type has a disadvantage that the light distribution and the light uniformity are lower than that of the side emission type.

A light emitting diode of a general side emitting type includes a lens for emitting light emitted from a light emitting diode chip in a lateral direction. Such a lens includes a funnel-shaped total internal reflection surface and a refracting surface which are symmetrical with respect to the central axis of the lens, And the refracting surface is formed in a serrated shape to refract light in a direction perpendicular to the central axis and emit.

The light emitting diode of the general side emission type is mounted inside the holes formed in the light guide plate, and the light emitted from the light emitting diode chip is emitted to the side of the lens and incident on the light guide plate. A light emitting diode of a general side emission type requires a lens having a very large height as compared with the height of the LED chip so that the thickness of the light emitting diode is determined by the thickness of the lens. Accordingly, there is a limit in reducing the thickness of the direct-type backlight unit (BLU) or the planar light source including the side-emitting type light emitting diode. These technical limitations are a fatal drawback to efforts to reduce the thickness of flat panel displays in recent years.

In addition, when light emitted from the light emitting diode chip is incident on the lens, a part of the light is reflected from the lower surface of the lens, and it is difficult to precisely process the total reflection surface and the refracting surface of the lens, There is a problem that the light extraction efficiency emitted from the light source is reduced.

Korean Patent Registration No. 10-1299528

The present invention relates to a side light emitting diode capable of improving light extraction efficiency to a side by reflecting light emitted to an upper portion or a lower portion side by side using a reflection layer and forming a light extracting structure on a side thereof to effectively emit light, A planar light source and a method of manufacturing the planar light source are provided.

A side light emitting diode according to an embodiment of the present invention includes a substrate having a first light extracting structure formed on a side surface thereof; A first reflective layer formed on one surface of the substrate; A semiconductor stacked structure formed on the other surface of the substrate opposite to the one surface of the substrate and including an n-type semiconductor layer, an active layer, and a p-type semiconductor layer; And a second reflective layer formed on the semiconductor stacked structure, and light emitted from the active layer may be emitted to the side of the substrate or the semiconductor stacked structure.

The first light extracting structure may be a protrusion or a concave portion formed by patterning a side surface of the substrate.

The first light extracting structure may be formed on a side surface of the substrate in a direction parallel to one surface of the substrate.

A second light extracting structure may be formed on a side surface of the semiconductor stacked structure.

The second light extracting structure may be formed on a side surface of the semiconductor multilayer structure in a direction parallel to the other surface of the substrate.

The substrate may have a concavo-convex structure on at least one of the one surface and the other surface.

According to another aspect of the present invention, there is provided a planar light source comprising: a plurality of the side light emitting diodes; A bottom plate on which wiring lines for providing electrical signals to the side light emitting diodes are formed; And a light guide plate provided on the lower plate and having a plurality of receiving portions for receiving the side light emitting diodes.

The receiving portion may have a side wall perpendicular to an upper surface of the light guide plate, and the side light emitting diode may be received in the receiving portion such that the side surface thereof is perpendicular to the upper surface of the light guide plate.

And a diffusion plate provided on the light guide plate and uniformly emitting light emitted from the side light emitting diode.

The lower plate may include a reflecting surface for reflecting incident light upward.

The phosphor may be provided in the space of the receiving portion in which the side light emitting diodes are housed.

At least one reflective layer of the first reflective layer and the second reflective layer may include a light exit port for emitting light emitted from the active layer to the outside.

According to another aspect of the present invention, there is provided a method of fabricating a side light emitting diode, comprising: forming a first light extracting structure by patterning a protrusion or a recess on a side surface of a substrate; Forming a first reflective layer on one surface of the substrate; Forming a semiconductor stacked structure including an n-type semiconductor layer, an active layer, and a p-type semiconductor layer on the other surface of the substrate opposite to the one surface of the substrate; And forming a second reflective layer on the semiconductor stacked structure.

And forming a second light extracting structure by patterning a protrusion or a recess on a side surface of the semiconductor multilayer structure.

The method may further include forming a concavo-convex structure on at least one of a first surface and a second surface of the substrate.

The first light extracting structure or the second light extracting structure may be formed on a side surface of the substrate or the semiconductor stacked structure in a direction parallel to one surface of the substrate.

The side light emitting diode according to the present invention may form a light extracting structure on a side surface of the substrate or the semiconductor stacked structure to effectively emit light emitted through the side surface of the light emitting diode. In addition, since the light extracting structure can improve the intensity of light emitted to the side center portion of the side light emitting diode, the surface light source including such a side light emitting diode has a large amount of light incident perpendicularly to the incident surface of the light pipe The reflectance is reduced and the light distribution characteristic can be improved.

In addition, since the side light emitting diode of the present invention can form a reflective layer on the top and bottom of the semiconductor stacked structure, light can be emitted directly to the side of the light emitting diode, so that a lens which is essentially used in the conventional side emitting type light emitting diode The thickness of the side light emitting diode can be remarkably reduced. Accordingly, the thickness of the planar light source including the side light emitting diode can be effectively reduced, and even if a plurality of light sources are disposed immediately below the light emitting surface, the planar light source is not directly emitted to the upper portion but emitted through the light guide plate. And it is possible to use a larger number of light emitting diodes than to arrange the light emitting diodes on the side surfaces, thereby providing a high luminance.

In addition, in the present invention, the light extracting efficiency to the side can be improved by forming the concavo-convex structure on at least one side of the both surfaces of the substrate to effectively extract the light emitted from the semiconductor stacked structure through the side surface of the light emitting diode, It is possible to improve the optical characteristics of the surface light source including the side light emitting diode or the direct-type backlight unit (BLU).

Meanwhile, in the present invention, not only the thickness of the planar light source can be reduced by stacking the planes constituting the planar light source, but also the planar light source can be modularized, which is convenient to use and can be easily packaged.

1 is a cross-sectional view illustrating a side light emitting diode according to an embodiment of the present invention;
2 is a perspective view illustrating a shape of a side light emitting diode according to an embodiment of the present invention;
3 is a view illustrating an effect of a light extracting structure of a side light emitting diode according to an embodiment of the present invention.
4 is an exploded perspective view showing a structure of a planar light source according to another embodiment of the present invention.
5 is a view illustrating a receiving portion and a side light emitting diode formed in a light guide plate of a planar light source according to another embodiment of the present invention.
6 is a flowchart showing a method of manufacturing a side light emitting diode according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. In the description, the same components are denoted by the same reference numerals, and the drawings are partially exaggerated in size to accurately describe the embodiments of the present invention, and the same reference numerals denote the same elements in the drawings.

1 is a cross-sectional view illustrating a side light emitting diode according to an embodiment of the present invention.

Referring to FIG. 1, a side light emitting diode 100 according to an embodiment of the present invention includes a substrate 110 having a first light extracting structure 111 formed on a side surface thereof; A first reflective layer 120 formed on one surface of the substrate 110; An active layer 132 and a p-type semiconductor layer 133, which are formed on the other surface of the substrate 110 facing the one surface of the substrate 110, and which include an n-type semiconductor layer 131, an active layer 132, ); And a second reflective layer 140 formed on the semiconductor laminated structure 130. The light emitted from the active layer 132 may be incident on the substrate 110 or the side surface of the semiconductor laminated structure 130 Can be released.

The substrate 110 may be formed of a substrate suitable for growing a compound semiconductor in a single crystal or an epitaxial manner and may be formed of a material such as sapphire, gallium nitride (GaN), zinc oxide (ZnO), silicon carbide (SiC), aluminum nitride Glass, silicon or PET (polyethylene terephthalate (PET)). However, the material is not particularly limited to these materials.

Table 1 is a table showing characteristics of each side light emitting diode according to one embodiment of the present invention.

shape triangle Square hexagon 12 square Top surface area 436,484 탆 2 435,600 탆 2 436,737 탆 2 437,811 탆 2 + 0.2% REF + 0.26% + 0.51% Side area 391,560 탆 2 343, 200 탆 2 319,800 탆 2 308,412 탆 2 + 14.09% REF -6.82% -10.14% Light extraction efficiency 38.5% 32.38% 33.3% 31.03%

FIG. 2 is a perspective view illustrating a side light emitting diode according to an embodiment of the present invention. FIG. 2 (a) is a side light emitting diode having no light extracting structure, and FIG. 2 (b) FIG. 2 (c) is a side-view light-emitting diode having a light extracting structure with two recesses.

Referring to Table 1 and FIG. 2, the substrate 110 may be a polygonal plate such as a triangular (FIG. 2), hexagonal, or hexagonal shape in addition to a general REF shape. The light extraction efficiency can be controlled by varying the shape of the substrate 110 because the side surface area varies depending on the shape of the substrate 110 and thus the light extraction efficiency is changed. Among the shapes of the polygonal substrate to which the upper surface area is similarly applied, the triangular shape can have the widest side surface area, and the rectangular shape side surface area can be widened by about 14%. As described above, when the side surface area is widened, the light extraction efficiency in the lateral direction can be improved. On the other hand, in the hexagonal shape, the light extracting efficiency is 0.92% higher than that of the square shape, and the possibility of light escape by various side angles can be increased.

The first light extracting structure 111 may be formed on a side surface of the substrate 110. The first light extracting structure 111 may be formed on the side surface of the substrate 110. The light may be refracted or scattered on the side surface of the substrate 110 to reduce the internal reflection of light, It is also possible to improve the light distribution characteristic by adjusting the light output direction.

The first light extracting structure 111 may be a protruding portion or a concave portion formed by patterning the side surface of the substrate 110. As shown in FIG. 2 (b), the protrusions or recesses may be formed as one or two as shown in FIG. 2 (c), but the number of the protrusions or recesses is not limited thereto. When the first light extracting structure 111, which is a protrusion or a recess, is formed on the side surface of the substrate 110, the light is refracted or scattered at the side surface of the substrate 110, It can be effectively emitted and the light extraction efficiency can be improved.

The first light extracting structure 111 may be formed on a side surface of the substrate 110 in a direction parallel to one surface of the substrate 110. When the first light extracting structure 111 is formed in a direction perpendicular to one surface of the substrate 110, light is refracted from the side surface of the substrate 110, and light is dispersed right and left in a direction perpendicular to one surface of the substrate 110 Accordingly, the light in the lateral direction can not be condensed and the uniformity of light may be lowered. Further, the number of protrusions or recesses may be increased for effective light extraction.

However, if the first light extracting structure 111 is formed long in a direction parallel to one surface of the substrate 110 as in the present invention, it is possible to prevent the light from being dispersed to the right and left in a direction perpendicular to the surface of the substrate 110 The number of protrusions or recesses can be reduced by the thickness of the substrate 110 and protrusions or recesses can be continuously formed on all sides of the substrate 110 to easily form the first light extracting structure 111 . Further, according to the shape and number of the first light extracting structure 111, the light dispersed on the side surface and the lower surface can be condensed to the side central portion, and the light uniformity of the light emitted to the side surface can be increased to improve the light distribution characteristic.

FIG. 3 is a view showing the effect of the light extracting structure of the side light emitting diode according to the embodiment of the present invention. FIG. 3 (a) shows the light extracting efficiency of the side light emitting diode according to the shape of the light extracting structure, 3 (b) shows the light intensity of the side light emitting diode according to the shape of the light extracting structure, and FIG. 3 (c) shows the light distribution shape of the side light emitting diode according to the shape of the light extracting structure.

3, it can be seen that B and C in which the first light extracting structure 111 is formed rather than A in which the first light extracting structure 111 is not formed have improved light extraction efficiency. In this manner, when the first light extracting structure 111 is formed, light extraction efficiency can be improved. 3A, the light extraction efficiency is further improved in the case where there are two concave portions (C) in the case of one concave portion (B), but the light extraction efficiency is not proportional to the number of concave portions, The extraction efficiency of light was 46.87%, which was lower than that of the case with two recesses.

As shown in FIG. 3B, in the case where the first light extracting structure 111 is not formed, a light leaking phenomenon occurs on a side surface and a lower surface, while B and C, in which the first light extracting structure 111 is formed, The intensity of light emitted to the side center portion of the light emitting diode 100 is increased and the uniformity of the light emitted to the side is improved. This allows the first light extracting structure 111 to efficiently emit light to the side center portion of the side light emitting diode 100 and improve the uniformity of the light emitted to the side, The characteristics can be improved. This seems to be an effect depending on the shape of the first light extracting structure 111 formed to be long in a direction parallel to one surface of the substrate 110. Since the uniformity of the light emitted to the side is improved by increasing the intensity of the light emitted to the side center portion of the side light emitting diode 100 and the light distribution characteristic of the side light emitting diode 100 is improved, The light incident on the incident surface of the light guide plate at a high angle (for example, vertical) can be increased in the surface light source of the side light emitting diode 100. Therefore, if the reflectance of the light emitted from the side light emitting diode 100 is reduced, . On the other hand, in the case of one concave portion (B), the intensity of light emitted to the center portion of the side surface of the side light emitting diode 100 is further increased in the case of two concave portions (C) The intensity of outgoing light was not proportional to the number of concave parts, but the number of concave parts was lower than that of two concave parts.

3C, it can be confirmed that light is uniformly emitted to the side surface of the side light emitting diode 100 when the first light extracting structure 111 is formed (C). A, in which the first light extracting structure 111 is not formed, is a phenomenon in which light leaks toward the upper side and the lower side of the side light emitting diode 100 and the side central portion (a portion corresponding to angles of 90 ° and 270 ° in FIG. The light is almost not emitted, and a deviation occurs on the side and the bottom, and light is emitted while maintaining the shape of the substrate 110. The planar light source including the light emitting diode having the same structure as that of the first light extracting structure 111 is difficult to achieve uniform surface light emission by most light emitted to the side and the bottom of the light emitting diode.

However, in the case of C formed with the first light extracting structure 111, light can be emitted most from the side center portion of the side light emitting diode 100, light is uniformly emitted from the side of the side light emitting diode 100, So that the light distribution characteristic of the side light emitting diode 100 can be improved. The surface light source including the side light emitting diode 100 having the structure of C formed with the first light extracting structure 111 (for example, two concave portions) is disposed on the side of the center of the side surface of the side light emitting diode 100 So that the emitted light can easily enter into the light guide plate, so that uniform surface light emission can be stably provided.

Accordingly, the first light extracting structure 111 not only improves the light extraction efficiency, but also can emit light uniformly to the side surface of the side light emitting diode 100. In addition, since light incident perpendicularly to the incident surface of the light guide plate can be increased in the surface light source including the side light emitting diode 100, the reflectance of the light emitted from the side light emitting diode 100 is reduced, . Since the thickness of the substrate 110 is as thin as about 100 μm, the number of the first light extracting structures 111 can be reduced by the ease of forming the light extracting structure, the light extraction efficiency and the light extraction efficiency of the light emitted to the central portion of the side light emitting diode 100 It can be determined in consideration of the strength.

In the case of the protruding portion, the light extraction efficiency is improved compared with the case where the light extraction efficiency is formed by the concave portion. However, the intensity of the light emitted to the side center portion of the side light emitting diode 100 The uniformity of the light emitted to the side surface of the side light emitting diode 100 is lower than that in the case of the recessed portion. The reason why the light extraction efficiency is higher is that the light emitted to the air may be incident on the side surface of the substrate 110 when the light emitting diode 100 is formed as a concave portion, The reason why the intensity of the light is low is because the light spreads up and down by the convex shape. The height of the concave portion and the protruding portion is not greater than the thickness of the substrate 110, and the height of the concave portion and the protruding portion of the substrate 110 The height of the concave portion and the protrusion can be determined depending on the thickness. Therefore, the shape of the first light extracting structure 111 can be determined in consideration of the light extraction efficiency and the intensity of the light emitted toward the center of the side surface of the side light emitting diode 100.

The semiconductor stacked structure 130 may be formed on the other surface of the substrate 110 opposite to one surface of the substrate 110 on which the first reflective layer 120 is formed and may include an n-type semiconductor layer 131, an active layer 132, And the p-type semiconductor layer 133. The n-type semiconductor layer 131, the active layer 132 and the p-type semiconductor layer 133 may be formed of a compound semiconductor material doped with each conductive impurity , For example, a gallium nitride compound semiconductor material having a composition formula of In x Al y Ga 1 -x- y N (where 0? X? 1 , 0? Y? 1, 0? X + y? 1) But is not particularly limited to these materials.

The n-type semiconductor layer 131 may be formed of a compound semiconductor layer doped with an n-type conductive impurity, and examples of the n-type conductive impurity include Si, Ge, and Sn. Si can be used. The active layer 132 may be formed of a single quantum well layer or a multi-quantum well layer composed of a double heterostructure or an InGaN / GaN layer. The p-type semiconductor layer 133 may be formed of a GaN layer or a GaN / AlGaN layer doped with a p-type conductivity type impurity. For example, Mg, Zn, Be or the like may be used as the p- And Mg can be mainly used. On the other hand, the semiconductor stacked structure 130 has various functions such as a GaN buffer layer, an n-type / p-type clad layer, and a p-type cap layer for improving lattice matching with a substrate formed of a material such as sapphire on the substrate 110 And may further include functional layers to perform. The n-type semiconductor layer 131 and the p-type semiconductor layer 133 are exposed to an n-type electrode (not shown) and a p-type electrode (not shown) by removing a part of the semiconductor stacked structure 130 through the etching process. May be formed to be in ohmic contact with each other.

In addition, the semiconductor light emitting structure 130 may have a second light extracting structure 135 formed on a side surface thereof. The light emitted from the active layer 132 is refracted or scattered by the side of the semiconductor stack structure 130 so as to reduce the internal reflection of the light so that the light is efficiently reflected by the semiconductor stack structure 130 And the light extraction efficiency to the side surface of the side light emitting diode 100 can be improved.

The second light extracting structure 135 may be formed on a side surface of the semiconductor stacked structure 130 in a direction parallel to the other surface of the substrate 110. If the second light extracting structure 135 is elongated in a direction parallel to the other surface (or one surface) of the substrate 110 like the first light extracting structure 111, the same effect as that of the first light extracting structure 111 It is possible to prevent the light from being dispersed right and left in a direction perpendicular to the other surface (or one surface) of the substrate 110 and to reduce the number of projections or recesses by the thickness of the semiconductor stacked structure 130 And protrusions or recesses can be continuously formed on all sides, so that the second light extracting structure 135 can be formed easily.

The second light extracting structure 135 may be formed together with the first light extracting structure 111 after the light emitting diode chip is formed or may be formed on the substrate 110 on which the first light extracting structure 111 is formed, 130 may be formed. Here, when the second light extracting structure 135 is formed together with the first light extracting structure 111 after the light emitting diode chip is formed, the first light extracting structure 111 and the second light extracting structure 135 are formed on the side of the light emitting diode chip, The extraction structure 135 may be formed of a single light extracting structure. Since the semiconductor laminated structure 130 is thin, it is difficult to form the second light extracting structure 135 only on the semiconductor laminated structure 130, so that the semiconductor laminated structure 130 is formed on the relatively thick substrate 110 The first light extracting structure 111 and the second light extracting structure 135 are formed as a single light extracting structure on the sides of the substrate 110 and the semiconductor stacked structure 130 to form a light extracting structure . On the other hand, if the second light extracting structure 135 is formed only on the semiconductor stacked structure 130, the light extracting structure can be formed on the substrate 110 and the semiconductor stacked structure 130 having different refractive indexes, Accordingly, the light extraction structure can be formed, and the light extraction can be performed more effectively according to the position of the light emission.

When the first light extracting structure 111 and the second light extracting structure 135 are formed together, the light extraction efficiency and the intensity of light emitted to the center of the side surface of the side light emitting diode 100 are further improved.

The first light extracting structure 111 and the second light extracting structure 135 may be formed by wet etching, femtosecond laser, laser scribing, or the like. Wet etching is an etching method using a liquid medicine having a property of dissolving only a target metal in a corrosive manner. The wet etching is a method of etching a first light extracting structure 111 and the second light extracting structure 135, respectively. Femtosecond lasers eliminate the localized part of the material in a very short time and do not cause thermal diffusion phenomenon in general laser processing. It is possible to process more precisely than thermal processing of existing laser. The thermal damage and structural change of the material may not occur. Using this femtosecond laser, the first light extracting structure 111 and the second light extracting structure 135 can be precisely formed on the side surfaces of the substrate 110 and the semiconductor stacked structure 130, which are thin. Laser scribing can be used to create break points for cutting semiconductors or ceramics where the first and second light extracting structures 111 and 135 are separated by laser scribing . Among the methods of forming the first light extracting structure 111 and the second light extracting structure 135, the thickness of the substrate 110 or the side light emitting diode chip and the thicknesses of the first light extracting structure 111 and the second light extracting structure 135 ) Can be determined in consideration of the shape of the surface.

The first reflective layer 120 and the second reflective layer 140 included in the side light emitting diode 100 may prevent light emitted from the active layer 132 of the semiconductor stack 130 from being emitted to the upper surface or the lower surface, A layer that reflects light to the inside and is emitted only from the side, and includes a metal reflection layer made of a metal and forming a mirror surface, or oxide layers having different refractive indices (e.g., SiO 2 and TiO 2 ) And may be a distributed Bragg reflection (DBR) layer formed by stacking. The first reflective layer 120 formed in contact with the substrate 110 may further include a buffer layer (e.g., SiO 2 layer) between the metal reflective layer and the substrate 110 to improve bonding properties, or may include a dispersed Bragg reflection (DBR) For example, the SiO 2 layer may be formed on the substrate 110, and may be formed on at least one of the upper surface and the lower surface of the substrate 110. If the SiO 2 layer is located below the semiconductor stack 130 It suffices. Meanwhile, a transparent electrode (for example, ITO) may be formed between the semiconductor stacked structure 130 and the second reflective layer 140.

The side light emitting diode 100 according to the present invention may emit light emitted from the active layer 132 directly to the side of the substrate 110 or the semiconductor stacked structure 130. The light emitted from the active layer 132 is not emitted to the upper surface or the lower surface of the side light emitting diode 100 of the present invention through the first reflective layer 120 and the second reflective layer 140, It can be directly discharged to the side. Therefore, the lens which is essentially used in the light emitting diode of the conventional side emission type is not required, and the thickness of the side light emitting diode 100 can be remarkably reduced.

The substrate 110 has a concavo-convex structure 150 formed on at least one of the one surface and the other surface of the substrate 110 so as to scatter light emitted from the active layer 132 and emit the light to the side surface of the light emitting diode 100 more effectively . The concave and convex structure 150 has a refractive index different from that of the compound semiconductor stacked structure 130 or has a reflective surface so that light emitted from the active layer 132 passes through the compound semiconductor stacked structure 130 The light path is refracted or light scattering occurs on the reflecting surface so that light is effectively emitted to the side of the light emitting diode. The shape of the light emitting diode may be hemispherical, pyramidal, cone, wedge, triangular, And the like.

The concavo-convex structure 150 formed on the other surface of the substrate 110 may have a protrusion protruding from the other surface of the substrate 110 toward the semiconductor stacked structure 130 when the first reflective layer 120 is formed on one surface of the substrate 110 151 may be formed of the same material as the substrate 110 by forming the substrate 110 by dry or wet patterning using an etching mask. For example, in the case of the sapphire substrate 110, the projecting portion 151, which is the concave-convex structure 150, is also made of sapphire and has a refractive index of 1.7, so that the light passes through the gallium nitride-based semiconductor stacked structure 130 having a refractive index of 2.4 When the light reaches the protrusion 151, the path of the light is refracted by the protrusion 151 due to the difference in refractive index. The protrusion 151 as the concavo-convex structure 150 formed on the other surface of the substrate 110 is formed by forming an oxide layer (for example, an SiO 2 layer having a refractive index of 1.4) on the substrate 110, May be formed by patterning using an etching mask. The protrusion 151 which is the concave-convex structure 150 formed on the other surface of the substrate 110 can reduce the dislocation density of the semiconductor stack 130 so that the thin film can be well grown on the substrate 110 , And may be provided apart from each other to provide nucleation sites for growth of the semiconductor stack structure 130 formed on the substrate 110. When the semiconductor stack structure 130 is formed on the substrate 110 partially exposed between the protrusions 151 as described above, the semiconductor stack structure 130 does not form an empty space between the protrusions 151 It can grow into single crystal or epitaxial.

The concavo-convex structure 150 formed on the other surface of the substrate 110 may be formed as a concave portion (not shown) recessed inside the substrate 110 from the other surface of the substrate 110. The recess (not shown) may be filled with at least one of air (refractive index 1), oxide (for example, SiO 2 having a refractive index of 1.4), or a semiconductor layer. When a concave portion (not shown) is formed on the other surface of the substrate 110, when light reaches the concave portion through the gallium nitride-based semiconductor laminated structure 130 having a refractive index of 2.4, the air / semiconductor, , The light path is refracted in the recess due to the refractive index difference between the semiconductor and the substrate.

An uneven structure 150 may be formed on one surface of the substrate 110, which is an insert 152 inserted into one surface of the substrate 110. An etch mask having an opening having a desired shape is formed on the lower surface of the substrate 110 and a recess (not shown) is formed by patterning the substrate 110 by a wet etching or a dry etching method, When the first reflective layer 120 is formed on one side of the substrate 110, the material forming the first reflective layer 120 may fill at least a part of the concave portion in the process of forming the first reflective layer 120, The protrusion structure 150 is formed as an insert 152 (or a protrusion extending from the first reflection layer) inserted into one surface of the base plate 150. In addition, one surface of the substrate 110 may be patterned to form an uneven structure 150 as a protrusion (not shown).

Since the insert 152 is formed by filling the material forming the first reflective layer 120 while forming the first reflective layer 120 after patterning the substrate 110, The light emitted from the light emitting diode 132 may be reflected and effectively extracted through the side surface of the side light emitting diode 100.

The conventional side light emitting diode (or the light emitting diode of the side emitting type) does not emit light directly from the side of the light emitting diode chip but uses light emitted from the upper or lower emitting type general LED chip Emitting diode in a lateral direction. In such a conventional side light-emitting diode, a lens for changing the direction of light is necessarily required. Since such a lens has a very large height compared with the height of the LED chip, The total thickness of the side light emitting diodes has to be thick depending on the thickness. However, the side light emitting diode 100 according to the present invention is a side light emitting diode chip in which light can be emitted directly from the side of the light emitting diode chip without a lens. Unlike the conventional side light emitting diode, The thickness of the substrate 100 can be significantly reduced.

4 is an exploded perspective view illustrating a structure of a planar light source according to another embodiment of the present invention.

Referring to FIG. 4, the planar light source according to another embodiment of the present invention will be described in more detail. However, the elements overlapping with those described above in connection with the side light emitting diode according to an embodiment of the present invention will be omitted.

A planar light source 1000 according to another embodiment of the present invention includes a plurality of side light emitting diodes 100 according to an embodiment of the present invention; A bottom plate 200 having a wiring for providing an electrical signal to the side light emitting diode 100; And a light guide plate 300 provided on the lower plate 200 and having a plurality of receiving portions 310 in which the side light emitting diodes 100 are received.

The side light emitting diode 100 may include a plurality of side light emitting diodes 100 according to an embodiment of the present invention. The light emitting diodes 100 may directly emit light emitted from the side light emitting diodes 100. In addition, since the side light emitting diode 100 forms a reflection layer on the upper and lower sides, the light emitted from the inside is directly emitted to the side of the light emitting diode without the lens for emitting the light to the side in the light emitting diode of the side emitting type. The thickness of the light guide plate 300 can be effectively reduced. The side light emitting diode 100 may include n-type and p-type bonding metals 160 (or bonding pads) and may be electrically connected to the bottom plate 200 by bonding n-type and p- . Here, the side light emitting diode 100 may be flip-chip bonded and electrically connected or may be electrically connected by a bonding wire.

The bottom plate 200 may be electrically connected to the external power source 500 by electrically connecting the plurality of side light emitting diodes 100 to the side light emitting diodes 100. Further, the light guide plate 300 may be a basic base on which the light guide plate 300 can be stacked.

The lower plate 200 may include a connection portion 210 that can be electrically connected to an external device. The connection part 210 is a part electrically connected to the side light emitting diode 100. The connection part 210 can easily be electrically connected to the connection part 210 by bonding the side light emitting diode 100 to the electrode without complicated structure or additional process have. The connection part 210 may be formed in the form of a connection pad or the like so that the n-type and p-type bonding metal 160 of the side light emitting diode 100 are aligned with the electrodes and bonded to the connection part 210, And the shape and the formation method are not limited.

The lower plate 200 may be made thin to reduce the thickness of the entire surface light source 1000. In order to reduce the thickness of the lower plate 200, the wiring may be formed by a printing process using conductive ink, Ions may be deposited, and there is no particular limitation on the wiring method for reducing the thickness. The lower plate 200 may be made of a soft material using a flexible material or may be made of a metal plate capable of reflecting light.

The lower plate 200 may include a reflective surface that reflects incident light upward. The reflective surface may be a light incident on the lower plate 200 through the light guide plate 300, The light incident on the bottom plate 200 directly from the side light emitting diode 100 can be reflected to the top (or the light emitting surface direction) without being incident on the light emitting device 300. The reflective surface reflects the light incident from the bottom surface of the light guide plate 300 so that the reflected light can be emitted to the upper surface (or the light emitting surface) via the light guide plate 300, The reflection plate may be formed of a metal plate such as aluminum or the like that is formed as a reflection layer or can reflect light. The reflection plate may be formed only on the surface contacting the light guide plate 300, ), Or may be formed on all the surfaces, but there is no particular limitation on the material and the forming method.

In addition, the bottom plate 200 may be formed of a light-transmissive material capable of transmitting light. When the light-transmissive material is formed, a double-side emission type planar light source capable of emitting light from both the front and rear sides can be manufactured. The translucent material may be, for example, glass or a transparent polymer, but the material is not particularly limited.

The light guide plate 300 may be provided on the lower plate 200 and forms a uniform planar light source while guiding light from one side or both sides by using refraction and reflection of light. Can be used to make a surface light source. The light guide plate 300 may be made of polymethyl methacrylate (PMMA) or polycarbonate (PC). The light guide plate 300 may be formed by injection molding or by extruding the molten resin composition using an extruder, It can be manufactured by forming a disk by cooling and then cutting it to a predetermined size. However, there is no particular limitation on the material and the method.

In addition, the light guide plate 300 may include a plurality of spaced apart receiving portions 310 capable of receiving a plurality of light sources, and a plurality of the side light emitting diodes 100 may be accommodated. Here, the side light emitting diodes 100 may be accommodated in the plurality of accommodating portions 310 such that the side surfaces of the side light emitting diodes 100 oppose the inner surface (or the incident surface) of the light guide plate 300. The receiving portion 310 may be formed as an open portion having an open top and bottom or a concave portion having only one side opened for electrical connection with the bottom plate 200. The forming method is not limited. The receiving portion 310 may have various shapes such as a square, a circle, a triangle, a diamond, and the like. The receiving portion 310 may have a size equal to or larger than the size of the light source to accommodate the light source, It is preferable that the size of the light source is larger than the size of the light source for inserting the phosphor for making. Further, the shape of the receiving portion 310 may be changed for controlling the light distribution characteristic of the surface light source (or the side light emitting diode) according to the present invention.

The receiving portion 310 may have a side wall vertical to the upper surface of the light guide plate 300 and the side light emitting diode 100 may be accommodated in the receiving portion 310 such that the side surface thereof is perpendicular to the upper surface of the light guide plate 300 . At this time, the side surface of the side light emitting diode 100 may face the inner surface (or the incident surface) of the light guide plate 300. In this case, since light incident on the incident surface of the light guide plate 300 at a high angle (for example, vertical) may be increased in the light emitted from the side light emitting diode 100, The light distribution characteristic of the light source 1000 can be improved if the reflectance of light is reduced.

The thickness of the light guide plate 300 may be equal to or greater than the thickness of the side light emitting diode 100. The thickness of the light guide plate 300 may be at least thicker than the thickness of the side light emitting diode 100 Most of the light emitted from the side light emitting diode 100 can be supplied to the light guide plate 300. However, when the thickness of the light guide plate 300 is thinner than the thickness of the side light emitting diode 100, the light emitted from the side light emitting diode 100 is emitted to a portion of the light guide plate 300, And is lost to the external space. When the thickness of the side light emitting diode 100 is greater than the thickness of the light guide plate 300, the side light emitting diode 100 protrudes and the upper or lower surface of the light guide plate 300 becomes uneven, It becomes difficult to stack other layers. Since the thickness of the light guide plate 300 depends on the thickness of the side light emitting diode 100, it is necessary to reduce the thickness of the side light emitting diode 100 in order to reduce the thickness of the light guide plate 300, The thickness of the planar light source 1000 can be reduced by reducing the thickness of the light guide plate 300 which occupies most of the entire thickness.

The planar light source 1000 may further include a diffusion plate 400 provided on the light guide plate 300 and uniformly emitting the light emitted from the side light emitting diode 100. The diffuser plate 400 may emit light uniformly from the plurality of side light emitting diodes 100 and diffuse and diffuse the light incident on the diffuser plate 400 and diffuse the light uniformly So that the brightness of the light can be improved. Polyethylene terephthalate (PET) or polycarbonate (PC) resin can be used as the material of the diffusion plate 400, and a particle coating layer serving as a diffusion is formed on the diffusion plate 400 However, there is no particular limitation on the material and the form. In addition, the diffusion plate 400 may form an optical pattern so that a light blocking effect may be realized to prevent the phenomenon that the intensity of the light is excessively deteriorated or the yellow light is led out. The optical pattern may be generally printed on the lower surface or the upper surface of the diffuser plate 400 or may be printed in a light shielding pattern using light shielding ink so that light is not concentrated, Is not a function that completely blocks light but may be implemented to adjust the light shielding degree or diffusivity of light with one optical pattern capable of performing a function of shielding and diffusing part of light.

The planar light source 1000 may further include an optical sheet such as a prism film, a brightness enhancement film (BEF), a protective film, a micro lens sheet, or a dual brightness enhancement film (DBEF) can do.

On the other hand, all the layers including the bottom plate 200 and the light guide plate 300 may be stacked. When all the layers are stacked, it is possible to reduce the total thickness of the planar light source 1000 and to thin the planar light source 1000, which is advantageous in developing a flexible planar light source that can be flexibly bent. In addition, a modular surface light source can be combined and simply packaged to be applicable to a backlight unit (BLU) or a lighting device. In addition, for a flexible planar light source, the components can be formed using a flexible material, and all the layers of the planar light source 1000 have flexibility, so that the planar light source 1000 as a whole is flexible ).

As described above, when the planar light source 1000 is manufactured with a small thickness and is flexible, it can be used as a backlight unit (BLU), can be used as an illumination device having excellent mobility and portability and easy installation . The backlight unit (BLU) is a surface light source for irradiating light from the back side of a liquid crystal display (LCD), and supplies light to a liquid crystal display (LCD) as a non-light emitting type electronic display device to display clear, It is an essential device which is indispensable for a liquid crystal display (LCD) because it can be realized with high quality. Recently, liquid crystal displays (LCDs) have been widely used from mobile phones to portable computers, monitors for computers, wall-mounted televisions, flexible displays, and the like, and thinner, lighter, and flexible If the planar light source 100 according to the present invention is used as a backlight unit (BLU), the requirement can be satisfied.

5A and 5B are schematic views showing a receiving portion and a side light emitting diode formed on a light guide plate of a planar light source according to another embodiment of the present invention, Is a sectional view showing a receiving portion and a side light emitting diode.

Referring to FIG. 5, a phosphor 312 may be provided in an empty space of the receiving portion 310 in which the side light emitting diode 100 is housed. The phosphor 312 serves to convert the light emitted from the side light emitting diode 100 into white light and may be implemented using a phosphor having a color complementary to the light emitted from the side light emitting diode 100. In one embodiment, a yellow phosphor may be used when the blue side light emitting diode is used. The blue phosphor (B) of 350 to 450 nm emitted from the blue side light emitting diode and the blue light (Y = R + G) in the wavelength region may be mixed to emit the white light W in the wavelength region of 480 to 530 nm. As the yellow phosphor, materials such as InGaN, YAG: Ce, and ZnS: Mn can be used.

The fluorescent material 312 may be provided in such a manner that it is mixed with a liquid epoxy or silicon or a combination of the transparent resin 311 to fill a clearance space and the fluorescent material 312, When the layer is formed of the fluorescent layer, the layer may be formed by coating, printing, spraying, or vapor deposition. There is no particular limitation on the manner of providing the layer. When the phosphor 312 is provided, it is preferable that the receiving portion 310 is completely filled with the surface of the light guide plate 300. In this case, the upper surface or the lower surface of the light guide plate 300 may be flat, Lt; RTI ID = 0.0 > 300 < / RTI >

At least one reflective layer of the first reflective layer 120 and the second reflective layer 140 may include a light emission port 170 that emits light emitted from the active layer 132 to the outside. At this time, the thickness of the light guide plate 300 may be thicker than the thickness of the side light emitting diode 100. The light emitting apertures 170 are formed to improve the light uniformity of the surface light source 1000. When the plurality of side light emitting diodes 100 are disposed directly under the surface light source, The upper or lower portion of the side light emitting diode 100 which is not emitted is relatively lower in brightness than the other portions. This problem can be solved by using the first reflective layer 120 or the second reflective layer 140 of the side light emitting diode 100, And a light output port 170 is formed in the light output port 170 to emit a certain amount of light upward or downward. The light output port 170 may be provided by forming one or more open portions in at least one of the first and second reflective layers 120 and 140. When two or more open portions are formed, However, the shape and the formation method are not particularly limited. The total width of the plurality of light output ports 170 is larger than the total width of the light output ports 170 formed on the upper surface or the lower surface of the side light emitting diode 100 That is, the first reflective layer or the second reflective layer) is preferably about 10% of the total area. However, the total area of the light emission apertures 170 can be determined in consideration of various factors. At this time, the light emitted from the light output port 170 may be much smaller than the light emitted from the side surface of the side light emitting diode 100.

When the light emitting orifice 170 is formed in the first reflective layer 120 or the second reflective layer 140 of the side light emitting diode 100, the depth of the receiving portion 310 is set to be greater than the thickness of the side light emitting diode 100 The light emitting portion 170 must be formed so that the phosphor 312 can be provided on the upper surface or the lower surface from which light is emitted. At this time, the phosphor 312 may be provided by a method of coating, printing, spraying, vapor deposition, or the like, and may be provided by the above-described providing method. It is important to flatten the upper surface (or lower surface) of the light guide plate 300. When the upper surface (or lower surface) of the light guide plate 300 is flattened, other layers can be easily stacked on the light guide plate 300. [

6 is a flowchart illustrating a method of manufacturing a side light emitting diode according to another embodiment of the present invention.

Referring to FIG. 6, a method of fabricating a side light emitting diode according to another embodiment of the present invention will be described in detail. The aspects of the side light emitting diode and the planar light source according to the embodiments of the present invention, Omit it.

According to another aspect of the present invention, there is provided a method of fabricating a side light emitting diode, comprising: forming a first light extracting structure by patterning protrusions or recesses on a side surface of a substrate; Forming a first reflective layer on one side of the substrate (S200); Forming a semiconductor stacked structure including an n-type semiconductor layer, an active layer, and a p-type semiconductor layer on the other surface of the substrate opposite to the one surface of the substrate (S300); And forming a second reflective layer on the semiconductor stacked structure (S400).

The above steps are not limited to the above procedure, and may be changed as necessary. In the manufacturing of the side light emitting diode, the above steps may be included. The above procedures represent one embodiment, which will be described below with reference to an embodiment.

First, a first light extracting structure is formed by patterning with protrusions or recesses on a side surface of a substrate (S100). When the first light extracting structure is formed on the substrate, the light is refracted or scattered at the side of the substrate, thereby reducing the internal reflection of the light, so that light can be effectively emitted and the light extraction efficiency to the side can be improved .

Next, a first reflective layer is formed on one side of the substrate (S200). The first reflective layer may be formed on one surface of the substrate, and may be formed on one of the upper surface and the lower surface of the substrate. The first reflective layer reflects light incident on the substrate among the light emitted from the active layer of the semiconductor stacked structure to allow light to be emitted only from a side surface of the side light emitting diode.

Next, a semiconductor stacked structure including an n-type semiconductor layer, an active layer, and a p-type semiconductor layer is formed on the other surface of the substrate opposite to the one surface of the substrate (S300). The semiconductor laminated structure may be formed on the other surface of the substrate, and the upper surface and the lower surface of the substrate may be formed on a surface facing the surface on which the first reflective layer is formed. The semiconductor laminated structure may be formed by stacking an n-type semiconductor layer, an active layer, and a p-type semiconductor layer, and light is emitted from the active layer.

Then, a second reflective layer is formed on the semiconductor stacked structure (S400). The second reflective layer reflects light emitted in a direction opposite to the substrate among the light emitted from the active layer of the semiconductor multilayer structure to the inside so as to emit light only from a side surface of the side light emitting diode.

Therefore, the first reflective layer and the second reflective layer may prevent light emitted from the active layer of the semiconductor stacked structure from being emitted to the upper surface or the lower surface, and may allow light to be reflected to the inside and be emitted only from the side. Therefore, the thickness of the side light emitting diode can be significantly reduced since a lens which has been essentially used in the conventional side emitting type light emitting diode is not required.

And forming a second light extracting structure by patterning a protrusion or a recess on a side surface of the semiconductor multilayer structure. When the second light extracting structure is formed on the side surface of the semiconductor laminated structure, light is refracted or scattered at the side surface of the semiconductor laminated structure, thereby reducing internal reflection of light. Therefore, light can be effectively emitted, The efficiency can be improved.

Meanwhile, the forming of the second light extracting structure may include forming the first light reflecting layer (S200), forming the second light reflecting layer (S400), and then forming the first light extracting structure May be performed simultaneously with step S100. The second light extracting structure may be formed together with the first light extracting structure after the light emitting diode chip is formed or may be formed after the semiconductor stacked structure is formed on the substrate on which the first light extracting structure is formed . Here, when the second light extracting structure is formed together with the first light extracting structure after the light emitting diode chip is formed, the first light extracting structure and the second light extracting structure may be formed on one side of the light emitting diode chip Or may be formed by a light extracting structure.

The method may further include forming a concavo-convex structure on at least one of a first surface and a second surface of the substrate. When the concave-convex structure is formed, light emitted from the active layer may be scattered to be more effectively emitted to the side surface of the side light emitting diode.

The first light extracting structure or the second light extracting structure may be formed on a side surface of the substrate or the semiconductor stacked structure in a direction parallel to one surface of the substrate. When the first light extracting structure or the second light extracting structure is formed long in a direction parallel to one surface of the substrate, it is possible to prevent the light from being dispersed to the right and left in a direction perpendicular to the one surface of the substrate, It is possible to reduce the number of protrusions or recesses by the thickness of the first light extracting structure or the second light extracting structure and to form the protrusions or recesses continuously on all sides.

As described above, in the present invention, the light extracting structure is formed on the side surface of the substrate or the semiconductor stacked structure, and the emitted light can be effectively emitted through the side surface of the light emitting diode. In addition, since the light extracting structure can improve the intensity of light emitted to the side center portion of the side light emitting diode, the surface light source including such a side light emitting diode has a large amount of light incident perpendicularly to the incident surface of the light pipe If the reflectance of light is reduced, the light distribution characteristic of the light source can be improved. Since a reflective layer is formed on the upper and lower portions of the semiconductor stacked structure, light can be emitted directly to the side of the LED, so that a lens that is essentially used in the conventional side emitting type LED is not needed. Can be significantly reduced. Accordingly, the thickness of the planar light source including the side light emitting diode can be effectively reduced, and even if a plurality of light sources are disposed immediately below the light emitting surface, the planar light source is not directly emitted to the upper portion but emitted through the light guide plate. And it is possible to use a larger number of light emitting diodes than to arrange the light emitting diodes on the side surfaces, thereby providing a high luminance. In addition, in the present invention, the light extracting efficiency to the side can be improved by forming the concavo-convex structure on at least one side of the both surfaces of the substrate to effectively extract the light emitted from the semiconductor stacked structure through the side surface of the light emitting diode, It is possible to improve the optical characteristics of the surface light source including the side light emitting diode or the direct-type backlight unit (BLU). Meanwhile, in the present invention, not only the thickness of the planar light source can be reduced by stacking the planes constituting the planar light source, but also the planar light source can be modularized, which is convenient to use and can be easily packaged. And the brightness of the upper or lower portion of the side light emitting diode is relatively lower than other portions through the light output port formed in the first reflective layer or the second reflective layer of the side light emitting diode.

As used in the above description, the term " on " means not only a direct contact but also a case of being opposed to the upper or lower surface, It is also possible to position them facing each other, and they are used to mean facing away from each other or coming into direct contact with the upper or lower surface. Thus, " on substrate " may be the surface (upper surface or lower surface) of the substrate, or it may be the surface of the film deposited on the surface of the substrate.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limited to the embodiments set forth herein. Those skilled in the art will appreciate that various modifications and equivalent embodiments may be possible. Accordingly, the technical scope of the present invention should be defined by the following claims.

100: side light emitting diode 110: substrate
111: first light extracting structure 120: first reflecting layer
130: semiconductor laminated structure 131: n-type semiconductor layer
132: active layer 133: p-type semiconductor layer
135: second light extracting structure 140: second reflective layer
150: concave / convex structure 151:
152: insert 160: n-type and p-type bonding metal
170: light output port 200:
210: connection part 300: light guide plate
310: accommodating portion 311: transparent resin
312: phosphor 400: diffuser plate
500: External power source 1000: Surface light source

Claims (15)

A substrate having a first light extracting structure formed on a side surface thereof;
A first reflective layer formed on one surface of the substrate;
A semiconductor stacked structure formed on the other surface of the substrate opposite to the one surface of the substrate and including an n-type semiconductor layer, an active layer, and a p-type semiconductor layer; And
And a second reflective layer formed on the semiconductor stacked structure,
And the light emitted from the active layer is emitted to the side of the substrate or the semiconductor stacked structure.
The method according to claim 1,
Wherein the first light extracting structure is a protrusion or a recess formed by patterning a side surface of the substrate.
The method according to claim 1,
Wherein the first light extracting structure is formed on a side surface of the substrate in a direction parallel to one surface of the substrate.
The method according to claim 1,
Wherein the semiconductor laminated structure has a second light extracting structure formed on a side surface thereof.
The method of claim 4,
Wherein the second light extracting structure is formed on a side surface of the semiconductor multilayer structure in a direction parallel to the other surface of the substrate.
The method according to claim 1,
Wherein the substrate has a concavo-convex structure on at least one of the one surface and the other surface.
A plurality of side light emitting diodes according to any one of claims 1 to 6;
A bottom plate on which wiring lines for providing electrical signals to the side light emitting diodes are formed; And
And a light guide plate provided on the lower plate and having a plurality of receiving portions for receiving the side light emitting diodes.
The method of claim 7,
Wherein the receiving portion has a side wall perpendicular to an upper surface of the light guide plate,
Wherein the side light emitting diode is housed in the accommodating portion such that a side surface thereof is perpendicular to an upper surface of the light guide plate.
The method of claim 7,
And a diffusion plate provided on the light guide plate and uniformly emitting light emitted from the side light emitting diode.
The method of claim 7,
Wherein a phosphor is provided in a clearance space of the containing portion in which the side light emitting diodes are housed.
The method of claim 7,
Wherein at least one of the first reflective layer and the second reflective layer includes a light exit port for emitting light emitted from the active layer to the outside.
Forming a first light extracting structure by patterning a protrusion or a recess on a side surface of the substrate;
Forming a first reflective layer on one surface of the substrate;
Forming a semiconductor stacked structure including an n-type semiconductor layer, an active layer, and a p-type semiconductor layer on the other surface of the substrate opposite to the one surface of the substrate; And
And forming a second reflective layer on the semiconductor stacked structure.
The method of claim 12,
And forming a second light extracting structure by patterning the semiconductor laminated structure with protrusions or recesses on a side surface of the semiconductor laminated structure.
The method of claim 12,
Further comprising the step of forming a concavo-convex structure on at least one of the one surface and the other surface of the substrate.
The method of claim 12,
Wherein the first light extracting structure or the second light extracting structure is formed on a side surface of the substrate or the semiconductor stacked structure in a direction parallel to one surface of the substrate.
KR1020150097173A 2015-07-08 2015-07-08 Edge light emitting diode, surface light having the same and method for fabricating the same KR101731489B1 (en)

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KR101299528B1 (en) 2012-12-18 2013-08-23 (주)애니캐스팅 Side emitting light emitting diode lens, back light unit and display device including the same

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