KR101078061B1 - Light emitting diode having a plurality of light emitting cells - Google Patents

Abstract

A light emitting diode having a plurality of light emitting cells is disclosed. The light emitting diode includes a plurality of light emitting cells positioned on a substrate and wirings connecting the plurality of light emitting cells. The plurality of light emitting cells may include external light emitting cells disposed near edges of the substrate and internal light emitting cells surrounded by external light emitting cells. Meanwhile, a horizontal cross section of each of the inner light emitting cells has a rectangular shape, and a horizontal cross section of each of the outer light emitting cells includes an inner edge positioned adjacent to a neighboring light emitting cell and an outer edge connected to the inner edge. The outer edges of the light emitting cells are non-parallel to any edge of the horizontal cross section of the inner light emitting cells. Accordingly, it is possible to provide a light emitting diode capable of reducing light loss due to total internal reflection in terms of external light emitting cells, thereby improving light extraction efficiency.

Description

LIGHT EMITTING DIODE HAVING A PLURALITY OF LIGHT EMITTING CELLS

The present invention relates to a light emitting diode, and more particularly to a light emitting diode having a plurality of light emitting cells.

A light emitting diode is an electroluminescent semiconductor device and emits light by recombination of electrons and holes. Such a light emitting diode is widely used as a display device and a backlight, and has a shorter power consumption and a longer life than a conventional light bulb or a fluorescent lamp, thereby replacing the incandescent lamp and the fluorescent lamp, thereby expanding its use area for general lighting.

In general, since the light emitting diode is driven when a forward current flows, the light emitting diode is repeatedly turned on and off according to the direction of the current under an AC power supply. Accordingly, when the light emitting diode is directly connected to an AC power source, the light emitting diode does not emit light continuously and is easily broken by reverse current. Furthermore, since a single light emitting diode is driven under a constant forward voltage, there is a problem that it cannot be driven under high voltage.

In order to solve the problem of the light emitting diode, a light emitting diode which can be directly connected to a high voltage AC power source is disclosed in International Publication No. WO 2004/023568 (Al) "Light-Emitting Device Having Light-Emitting Components" (LIGHT-EMITTING DEVICE HAVING LIGHT- EMITTING ELEMENTS has been disclosed by SAKAI et al., And other light emitting diodes have been developed.

According to WO 2004/023568 (Al), LED elements having a generally rectangular shape (hereinafter referred to as light emitting cells) form LED arrays connected two-dimensionally in series by metallization on a sapphire substrate and a single substrate. . These two LED arrays are connected in anti-parallel on the substrate, which can emit light continuously by an AC power supply, and can be driven under relatively high voltage by connecting a plurality of light emitting cells in series.

However, WO 2004/023568 (Al) uses rectangular shaped light emitting cells, whereby total internal reflection occurs when light generated in the light emitting cells is emitted through the side of the light emitting cells, thereby reducing the light loss. It is easy to occur.

Patent Document 1: International Publication No. WO 2004/023568 (Al)

An object of the present invention is to provide a light emitting diode that can improve the light extraction efficiency by reducing the light loss due to total internal reflection generated from the side of the light emitting cell.

Another object of the present invention is to provide a high voltage driving light emitting diode capable of improving light extraction efficiency by reducing light loss due to total internal reflection.

A light emitting diode according to embodiments of the present invention includes a substrate; A plurality of light emitting cells on the substrate; And wires connecting the plurality of light emitting cells. The plurality of light emitting cells may include external light emitting cells disposed near edges of the substrate and internal light emitting cells surrounded by the external light emitting cells. Meanwhile, a horizontal cross section of each of the internal light emitting cells has a rectangular shape. Further, the horizontal cross section of each of the external light emitting cells includes an inner edge positioned adjacent to a neighboring light emitting cell and an outer edge connected to the inner edge, and the outer edge of the external light emitting cells is a horizontal cross section of the inner light emitting cell. It is antiparallel to either edge of.

The light emitted through the side surface of the inner light emitting cell may proceed to the light emitting cell adjacent to the inner light emitting cell, for example, the external light emitting cell, and may be incident to the external light emitting cell. Light incident to the external light emitting cell may be emitted to the outside through the external light emitting cell, but may be absorbed and lost by the external light emitting cell. Therefore, the horizontal cross section of the internal light emitting cell is maintained in a rectangular shape to suppress light emission through the side surface. On the other hand, since the outer edge of the horizontal cross section of the external light emitting cell is non-parallel to the edge of the internal light emitting cell, it is possible to reduce the light loss due to total internal reflection at the outer side of the external light emitting cell, thus improving the light extraction efficiency of the light emitting diode. Can be improved.

The substrate may also have a rectangular shape, and the plurality of light emitting cells may be positioned on an area surrounded by an edge of the substrate. Further, edges of the substrate may be parallel to corresponding edges of the horizontal cross section of the internal light emitting cell, respectively. Thus, the outer edge of the outer light emitting cells is also non-parallel with respect to the edge of the substrate adjacent thereto.

On the other hand, the inner edge of the outer light emitting cells may be parallel to at least one of the edges of the horizontal cross section of the inner light emitting cell. Therefore, light generated in the external light emitting cells can be suppressed from being emitted through the inner side surface thereof and incident to the adjacent light emitting cells.

In some embodiments, outer edges of the outer light emitting cells may have a convex shape. Further, the outer edges of the external light emitting cells may form a circular or elliptical shape as a whole. By making the outer edge have a convex shape, total internal reflection generated at the outer side of the outer light emitting cell can be significantly reduced.

The light emitting diode may further include electrode pads. The electrode pads may be located inside the circular or oval shape, and the electrode pads may form part of the circular or oval shape.

In some embodiments, an outer edge of each of the external light emitting cells may have a straight shape. Furthermore, the outer edge of one external light emitting cell may be inclined in an opposite direction with respect to the outer edge of the external light emitting cell adjacent to the outer light emitting cells so that the outer edges of the external light emitting cells may form an uneven shape as a whole. On the other hand, the outer edge of one external light emitting cell is inclined in the same direction with respect to the outer edge of the outer light emitting cell adjacent to it so that the outer edges of the external light emitting cells may form a sawtooth shape as a whole.

In some embodiments, an outer edge of each of the external light emitting cells may have a recessed or concave shape, and an external light emitting cell having a concave outer edge and an outer light emitting cell having a concave outer edge may be alternately arranged. have. The recessed portion and the convex shape may have a curved shape, and outer edges of the external light emitting cells may have a wavy shape as a whole. Alternatively, the recessed portion and the convex shape may be an angular shape.

In some embodiments, electrode pads may surround the inner light emitting cells together with the outer light emitting cells.

Furthermore, between the electrode pads, the external light emitting cells and the internal light emitting cells may be connected in series with each other by the wirings, and thus a light emitting diode that may be driven at a high voltage may be provided.

In addition, the external light emitting cells and the internal light emitting cells may be connected by the wires to form at least two series arrays, and the at least two series arrays may be connected in parallel to each other between the electrode pads. . In contrast, the external light emitting cells may constitute a bridge rectifying circuit, and the internal light emitting cells may be connected in series with each other to be connected between two nodes of the bridge rectifying circuit. Accordingly, a light emitting diode that can be driven by being connected to an AC power source can be provided.

In some embodiments, the plurality of light emitting cells may include at least one full-wave light emitting cell and half-wave light emitting cells. Here, the "half wave light emitting cell" means a light emitting cell to which a forward voltage is applied during a half cycle of AC power and a reverse voltage is applied for another half cycle, or a reverse voltage is applied during a half cycle of AC power and a forward voltage is applied for another half cycle. In addition, the propagation light emitting cell refers to a light emitting cell to which a forward voltage is applied during the entire period of the AC power supply. The use of the light emitting cell can increase the use efficiency of the light emitting cell.

Furthermore, two adjacent half-wave light emitting cells may share an n-electrode or a p-electrode. The light emitting cells sharing the n-electrode or p-electrode are referred to as 'common light emitting cells'. By sharing the n-electrode or the p-electrode, the light emitting area of the half-wave light emitting cells can be increased, and there is no need to electrically separate the half-wave light emitting cells, thereby improving stability of the manufacturing process and device reliability.

According to the present invention, it is possible to use a smaller number of light emitting cells in order to provide the same amount of light by increasing the use efficiency of the light emitting cells, it is possible to provide an excellent light emitting diode in terms of productivity and cost reduction.

In addition, according to the present invention, by minimizing the reverse voltage applied to a single light emitting cell, it is possible to reduce the risk of breakage of the light emitting diode and to stabilize the light emitting diode against the reverse voltage.

In addition, the number of light emitting cells driven under a specific driving voltage may be increased.

1 is a schematic plan view illustrating a light emitting diode according to an embodiment of the present invention.
2 is a cross-sectional view taken along the line AA of FIG. 1.
3 is an equivalent circuit diagram of the light emitting diode of FIG. 1.
4 is a schematic plan view illustrating a light emitting diode according to still another embodiment of the present invention.
5 is a cross-sectional view taken along the line BB of FIG. 4.
6 is an equivalent circuit diagram of the light emitting diode of FIG. 3.
7 is a schematic plan view illustrating a light emitting diode according to still another embodiment of the present invention.
8 is an equivalent circuit diagram of the light emitting diode of FIG. 7.
9 is a schematic plan view illustrating a light emitting diode according to still another embodiment of the present invention.
FIG. 10 is an equivalent circuit diagram of the light emitting diode of FIG. 9.
11 is a schematic plan view for describing a light emitting diode according to still another embodiment of the present invention.
12 is a schematic plan view for describing a light emitting diode according to still another embodiment of the present invention.
FIG. 13 is a schematic plan view illustrating a light emitting diode according to still another embodiment of the present invention. FIG.
14 is a schematic plan view illustrating a light emitting diode according to still another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to ensure that the spirit of the present invention to those skilled in the art will fully convey. Accordingly, the present invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, lengths, thicknesses, and the like of layers and regions may be exaggerated for convenience. Like numbers refer to like elements throughout the specification.

In the embodiments of the present invention, the "half-wave light emitting cell" is applied with a forward voltage for half a period of an AC power source and a reverse voltage for another half period, or a reverse voltage for a half period of an AC power source and a forward voltage for another half period. This means a light emitting cell to be applied, and a radio wave light emitting cell means a light emitting cell to which a forward voltage is applied during the entire period of the AC power.

1 is a plan view illustrating a light emitting diode according to an exemplary embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line A-A of FIG. 1, and FIG. 3 is an equivalent circuit diagram of FIG. 1.

1 and 2, the light emitting diode includes a substrate 21, a plurality of light emitting cells 30 and 40, and wires 55. In addition, the light emitting diode may include first and second electrode pads 50a and 50b, and a transparent electrode layer (not shown), a p-electrode 53a, and n− may be disposed on the light emitting cells. An electrode 53b may be disposed, and the light emitting diode may include an insulating layer 29 or a protective layer (not shown).

The substrate 21 may be an insulating substrate such as sapphire, but is not limited thereto and may be a conductive substrate having an insulating layer thereon. In addition, the substrate 21 may be a growth substrate for growing the compound semiconductor layers, but is not limited thereto. The substrate 21 may be a support substrate attached to the grown compound semiconductor layer. The substrate 21 has a generally rectangular shape and may have a rectangular shape as shown.

The plurality of light emitting cells include external light emitting cells 30a to 30j disposed near the edge of the substrate 21 and internal light emitting cells 40a to 40d surrounded by the external light emitting cells. Here, four internal light emitting cells and 10 external light emitting cells are illustrated, but the number of internal light emitting cells and external light emitting cells is not particularly limited.

Each of the internal light emitting cells 40a to 40d is surrounded by adjacent other light emitting cells, for example, an external light emitting cell or another internal light emitting cell. Each of the internal light emitting cells 40a to 40d has a horizontal cross section of a rectangular shape. The edges of the horizontal cross sections of the internal light emitting cells 40a to 40d may be parallel to the edges of the substrate 21, respectively, as shown.

Meanwhile, a horizontal cross section of each of the external light emitting cells 30a to 30j includes an inner edge positioned adjacent to a neighboring light emitting cell and an outer edge connected to the inner edge. Here, the 'inner edge' means an edge facing the edge of the neighboring light emitting cell, and the 'outer edge' means an edge located at the edge side of the substrate 21. Therefore, the light emitted horizontally to the substrate toward the inner edge side will be incident to the neighboring light emitting cells, but the light emitted horizontally to the substrate toward the outer edge side can be emitted to the outside without interference from the neighboring light emitting cells. In addition, an inner edge of the outer light emitting cells 30a to 30j may be parallel to any one of edges of a horizontal cross section of the inner light emitting cells 40a to 40d. In contrast, the outer edges of the external light emitting cells 30a to 30d are non-parallel to any edge of the horizontal cross section of the internal light emitting cells 40a to 40d. Furthermore, the outer edges of the external light emitting cells 30a-30d are also nonparallel to the edges of the substrate 21.

In addition, the outer edges of the outer light emitting cells may have a convex shape as shown in FIG. 1, and the outer edges of the outer light emitting cells 30a to 30j may form a circular shape as a whole. Therefore, light emitted in the horizontal direction with respect to the substrate 21 can be easily emitted through the outer edges of the external light emitting cells 30a to 30j, thereby improving light extraction efficiency.

Furthermore, the electrode pads 50a and 50b may be located inside a circular shape formed by outer edges of the external light emitting cells. As illustrated, the electrode pads 50a and 50b may be the external light emitting cells 30a to 30j. ) May surround the inner light emitting cells 40a to 40d. That is, horizontal cross sections of the electrode pads 50a and 50b may constitute a part of the circular shape.

As shown in FIG. 2, the light emitting cells include a first conductive lower semiconductor layer 23, an active layer 25, and a second conductive upper semiconductor layer 27. The active layer 25 may be a single quantum well structure or a multi quantum well structure, and its material and composition are selected according to the emission wavelength required. For example, the active layer may be formed of an AlInGaN-based compound semiconductor, such as InGaN. The lower and upper semiconductor layers 23 and 27 may be formed of a material having a larger band gap than the active layer 25, and may be formed of an AlInGaN-based compound semiconductor such as GaN.

Meanwhile, a buffer layer (not shown) may be interposed between the lower semiconductor layer 23 and the substrate 21. The buffer layers may be spaced apart from each other, but are not limited thereto. When the buffer layers are formed of an insulating material or a high resistance material, the buffer layers may be continuous to each other.

As illustrated, the upper semiconductor layer 27 is positioned above a portion of the lower semiconductor layer 25, and the active layer 23 is disposed between the upper semiconductor layer 27 and the lower semiconductor layer 23. It is interposed. In addition, a transparent electrode layer (not shown) may be disposed on the upper semiconductor layer 27. The transparent electrode layer may be formed of an indium tin oxide (ITO) material or Ni / Au.

The lower semiconductor layer 23 and the upper semiconductor layer 27 may be n-type semiconductor layers and p-type semiconductor layers, respectively, or vice versa. In the present embodiment, the lower semiconductor layer 23 is an n-type semiconductor layer, and the upper semiconductor layer 27 is described as a p-type semiconductor layer. Accordingly, the n-electrode 53b is positioned on the lower semiconductor layer 23, and the p-electrode 53a is positioned on the upper semiconductor layer 27.

The first and second electrode pads 50a and 50b are pads for supplying power from an external power source, for example, pads to which a bonding wire may be bonded. The light emitting diode is driven by electric power applied to the first and second electrode pads 50a and 50b. The first and second electrode pads 50a and 50b may be positioned on the lower semiconductor layer 23 as illustrated, but are not limited thereto. The first and second electrode pads 50a and 50b may be disposed on the substrate 21 or on the upper semiconductor layer 27. It can also be located at.

The wirings 55 electrically connect adjacent light emitting cells to each other. That is, the wirings 55 connect the n-electrode 53b of one light emitting cell to the p-electrode 53a of the adjacent light emitting cell. Meanwhile, the insulating layer 29 is formed on side surfaces of the light emitting cells to prevent the upper semiconductor layer 27 and the lower semiconductor layer 23 from being shorted by the wiring 55. In this way, a plurality of light emitting cells may be connected in series.

1 and 3, the wirings 55 connect the light emitting cells 30 and 30 to each other to form a unidirectional light emitting cell array between the first electrode pad 50a and the second electrode pad 50b. do. The external light emitting cells and the internal light emitting cells may be connected in various ways using the wires 55. 1 illustrates that external light emitting cells and internal light emitting cells are sequentially connected in a row unit. For example, the first electrode pad 50a, the external light emitting cell 30a, the external light emitting cell 30b, the external light emitting cell 30c, the external light emitting cell 30d, the internal light emitting cell 40a, and the internal light emitting cell 40b. ), External light emitting cell 30e, external light emitting cell 30f, internal light emitting cell 40c, internal light emitting cell 40d, external light emitting cell 30g, external light emitting cell 30h, external light emitting cell 30i In this order, the external light emitting cells 30j and the second electrode pads 50b are sequentially connected through the wirings 55. Accordingly, a current flows from the first electrode pad 50a to the second electrode pad 50b via the external light emitting cell and the internal light emitting cell, and a plurality of light emitting cells are connected in series to provide a light emitting diode capable of driving at high voltage.

In the present embodiment, although the electrode pads 50a and 50b are illustrated and described as forming a circular shape together with the external light emitting cells 30a to 30j, the electrode pads 50a and 50b are formed in the circular shape. It may be located outside. For example, electrode pads 50a and 50b may be disposed near the edge of the substrate.

In addition, in the present embodiment, it has been described that the outer edges of the external light emitting cells 30a to 30j form a circular shape as a whole, but the present invention is not limited thereto. For example, an elliptic shape may be achieved.

4 is a schematic plan view illustrating a light emitting diode according to still another embodiment of the present invention, FIG. 5 is a cross-sectional view taken along the cutting line B-B of FIG. 4, and FIG. 6 is an equivalent circuit diagram of the light emitting diode of FIG. 4.

4 to 6, the light emitting diode according to the present embodiment includes external light emitting cells 60a to 60j and internal light emitting cells 70a to 70d on the substrate 21. The wires 85 are connected to each other. The light emitting diode according to the present embodiment is generally similar to the light emitting diode described with reference to FIGS. 1 to 3, but emits light by the wirings 85 between the first electrode pad 80a and the second electrode pad 80b. The difference is that two serial arrays of cells are formed and these serial arrays are connected in parallel with each other.

That is, the first electrode pad 80a, the external light emitting cell 60a, the internal light emitting cell 70a, the internal light emitting cell 70b, the external light emitting cell 60b, the external light emitting cell 60c, and the external light emitting cell 60d. ), The external light emitting cell 60e and the second electrode pad 80b are sequentially connected by the wirings 85 to form an array. In addition, the second electrode pad 80b, the external light emitting cell 60f, the internal light emitting cell 70c, the internal light emitting cell 70d, the external light emitting cell 70g, the external light emitting cell 60h, and the external light emitting cell 60i. ), The external light emitting cell 60j and the first electrode pad 80a are sequentially connected through the wirings 85 to form another array. These arrays are connected in anti-parallel between the first electrode pad 80a and the second electrode pad 80b, and thus can be bidirectionally driven under AC power.

The wires 85 may connect light emitting cells in series by connecting the p-electrode 83a of one light emitting cell and the n-electrode 83b of a light emitting cell adjacent to the light emitting cell. The wiring 85 may include an n-electrode 83b of one light emitting cell (eg 60b) and an n-electrode 83b of a light emitting cell (eg 60g) adjacent to the light emitting cell.

7 is a schematic plan view illustrating a light emitting diode according to still another embodiment of the present invention, and FIG. 8 is an equivalent circuit diagram of the light emitting diode of FIG. 7.

7 and 8, the light emitting diode according to the present embodiment is generally similar to the light emitting diode described with reference to FIGS. 1 to 3, but the external light emitting cells 110, 120, 130, and 140 are bridge rectified. There is a difference in that a circuit is formed and internal light emitting cells 100 are connected in series between two nodes of a bridge rectifying circuit constituted by the external light emitting cells.

That is, the external light emitting cells 110a to 110d; 110, the external light emitting cells 120a to 120c; 120, the external light emitting cells 130a to 130c; 130, and the external light emitting cells 140a to 140d; A bridge rectifying circuit is configured between the first electrode pad 150a and the second electrode pad 150b. The external light emitting cell 110 and the external light emitting cell 140 are connected to the first electrode pad 150a, and the external light emitting cell 120 and the external light emitting cell 130 are connected to the second electrode pad 150b. Meanwhile, the external light emitting cell 110 and the external light emitting cell 130 are connected at one node, and the external light emitting cell 120 and the external light emitting cell 140 are connected at the other node. Meanwhile, the internal light emitting cells 100 are connected to each other in series and are connected to the one node and the other node.

According to the present embodiment, a light emitting diode that can be driven under an AC power supply may be provided by configuring a bridge rectifying circuit using the external light emitting cells 110 to 140.

9 is a schematic plan view illustrating a light emitting diode according to another embodiment of the present invention, and FIG. 10 is an equivalent circuit diagram of the light emitting diode of FIG. 9.

9 and 10, the light emitting diode of this embodiment has a circular shape as a whole, similar to the light emitting diode described with reference to FIGS. 1 to 3. However, in the present embodiment, the electrode pads 180a and 180b are illustrated as being disposed outside the circular shape. However, in the present invention, as described with reference to FIGS. 1 to 3, the electrode pads 180a and 180b may be disposed in a circular shape.

Meanwhile, in the light emitting diode according to the present embodiment, two antiparallel arrays are formed between the first electrode pad 180a and the second electrode pad 180b similarly to the AC light emitting diode described with reference to FIGS. 4 to 6. However, these two anti-parallel arrays are connected by the wirings 185 in a structure sharing the propagation light emitting cells 160a, 170a, and 160b. That is, the light emitting cells 160a, 170a, and 160b may emit light during the entire period of the AC power supply as shown in FIG. 10. Therefore, the use efficiency of the light emitting cell can be increased in comparison with the light emitting diode described with reference to FIGS. 4 to 6.

Meanwhile, in the present embodiment, the half-wave light emitting cells 161a and 161b, 163a and 163b, 165a and 165b, 167a and 167b, 169a and 169b, and 171a and 171b are n-electrodes 183b or p-electrodes ( It consists of a common light emitting cell sharing 183a). Therefore, the area required to form the n-electrode or p-electrode can be reduced, and in addition, since the half-wave light emitting cells do not need to be separated, the area of the light emitting cells can be relatively large. However, the present invention is not limited thereto, and the half-wave light emitting cells may be configured as individual light emitting cells instead of the common light emitting cells.

In this embodiment, two half-wave light emitting cells are connected in series between the light emitting cells. Therefore, in the AC driving, the reverse voltage applied to the two half-wave light emitting cells between the full-wave light emitting cells is the same as the forward voltage applied to the two full-wave light emitting cells and the two half-wave light emitting cells. Therefore, the reverse voltage applied to each of the half-wave light emitting cells corresponds to the magnitude of the forward voltage applied to the two light emitting cells. That is, the reverse voltage corresponds to 2Vf. However, the present invention is not limited to a structure in which the reverse voltage is 2Vf, and one half-wave light emitting cell is connected in series between the light emitting cells, for example, to have a 3Vf structure.

11 to 14 are plan views illustrating light emitting diodes according to various embodiments of the present disclosure. In these drawings, electrode pads, electrodes, and wirings are omitted for clarity of illustration, and the cross-sectional shape of the light emitting cells is illustrated.

Referring to FIG. 11, the light emitting diode according to the present embodiment includes the external light emitting cells 230 disposed near the edge of the substrate 21 and the internal light emitting cells 240 surrounded by the external light emitting cells 230. It includes. The internal light emitting cells 240 have a horizontal cross section of a rectangular shape. On the other hand, the outer edge of each of the external light emitting cells 230 is a straight line shape, the outer edge of one external light emitting cell is inclined in the opposite direction with respect to the outer edge of the external light emitting cell adjacent to it. Accordingly, the outer edges of the external light emitting cells 230 form an uneven shape as a whole. The external light emitting cells 230 and the internal light emitting cells 240 may be formed to have substantially the same light emitting area as each other.

The external light emitting cells 230 and the internal light emitting cells 240 are connected to each other in various ways through wires (not shown), for example, as shown in the embodiments of FIGS. 1, 4, 7, or 9. Can be electrically connected.

Referring to FIG. 12, the light emitting diode according to the present exemplary embodiment is generally similar to the light emitting diode described with reference to FIG. 11, but the outer edge of one external light emitting cell 250 is opposite to the outer edge of the external light emitting cell adjacent thereto. There is a difference between inclined in the same direction. Accordingly, the outer edges of the external light emitting cells 250 form a sawtooth shape as a whole.

Referring to FIG. 13, the light emitting diode according to the present exemplary embodiment is generally similar to the light emitting diode described with reference to FIG. 11, except that an outer edge of each of the external light emitting cells 260 has a recessed or convex shape. In the present embodiment, the recessed portion and the convex shape are curved, and the outer light emitting cell having the outer edge of the concave portion and the outer light emitting cell having the outer edge of the concave shape are alternately arranged so that the outer edge of the outer light emitting cells They are all wavy.

Referring to FIG. 14, the light emitting diode according to the present exemplary embodiment is generally similar to the light emitting diode described with reference to FIG. 13, but the outer edges of the external light emitting cells 270 have a mountain-shaped recess or a valley-shaped convex shape. The outer light emitting cells having the outer edges of the concave portion and the outer light emitting cells having the outer edges of the convex shape are alternately arranged so that the outer edges of the outer light emitting cells form an uneven shape as a whole.

While some embodiments of the present invention have been described above by way of example, those skilled in the art will appreciate that various modifications and variations can be made without departing from the essential features of the present invention. Therefore, the embodiments described above should not be construed as limiting the technical spirit of the present invention but merely for better understanding. The scope of the present invention is not limited by these embodiments, and should be interpreted by the following claims, and the technical spirit equivalent to the scope of the present invention should be construed as being included in the scope of the present invention.

Claims (17)

Board;
A plurality of light emitting cells on the substrate; And
Including wires for connecting the plurality of light emitting cells,
The plurality of light emitting cells may include external light emitting cells disposed near edges of the substrate and internal light emitting cells surrounded by the external light emitting cells.
The horizontal cross section of each of the internal light emitting cells has a rectangular shape,
A horizontal cross section of each of the external light emitting cells includes an inner edge positioned adjacent to a neighboring light emitting cell and an outer edge connected to the inner edge;
The outer edges of the outer light emitting cells are non-parallel to any edge of the horizontal cross section of the inner light emitting cells. The method according to claim 1,
An inner edge of the outer light emitting cells is parallel to at least one of the edges of the horizontal cross-section of the inner light emitting cell. The method according to claim 1,
An outer edge of the outer light emitting cells has a convex shape. The method according to claim 3,
The outer edges of the outer light emitting cells of the light emitting diode having a circular or elliptical shape as a whole. The method of claim 4,
The light emitting diode further comprises electrode pads, wherein the electrode pads are located inside the circular or elliptical shape. The method according to claim 1,
The outer edge of each of the external light emitting cells is a light emitting diode, characterized in that the straight shape. The method of claim 6,
The outer edge of one external light emitting cell is inclined in the opposite direction with respect to the outer edge of the adjacent external light emitting cell so that the outer edges of the external light emitting cells as a whole have an uneven shape. The method of claim 6,
An outer edge of one outer light emitting cell is inclined in the same direction with respect to the outer edge of the outer light emitting cell adjacent to the light emitting diode so that the outer edges of the outer light emitting cells as a whole sawtooth shape. The method according to claim 1,
The outer edge of each of the external light emitting cells is a recess or convex shape, the outer light emitting cell having an outer edge of the recess shape and the outer light emitting cell having an outer edge of the concave shape alternately arranged. The method according to claim 9,
The recessed portion and the convex shape may have a curved shape, and the outer edges of the outer light emitting cells may have a wavy shape as a whole. The method according to claim 1,
Light emitting diodes further comprising electrode pads surrounding the inner light emitting cells together with the outer light emitting cells. The method of claim 11,
The external light emitting cells and the internal light emitting cells are connected to each other in series by the wirings between the electrode pads. The method of claim 11,
And the external light emitting cells and the internal light emitting cells are connected by the wirings to form at least two series arrays, and the at least two series arrays are anti-parallel to each other between the electrode pads. The method of claim 11,
The external light emitting cells constitute a bridge rectifying circuit, and the internal light emitting cells are connected to each other in series and connected between two nodes of the bridge rectifying circuit. The method according to claim 1,
The plurality of light emitting cells include at least one full-wave light emitting cell. The method according to claim 1,
The plurality of light emitting cells include at least one common light emitting cell. The method according to claim 16,
The common light emitting cell shares a p-electrode.

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