KR100632205B1 - Light emitting diode having light guide part and manufacturing method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode having a light guide portion and a method of manufacturing the same. In particular, in a light emitting diode including light emitting cells arranged in a matrix, light incident on a substrate in a horizontal direction is collected from adjacent light emitting cells. The present invention relates to a light emitting diode having a light guide portion having improved light emission efficiency by a light guide portion guiding to be emitted in a direction, and a method of manufacturing the same.

To this end, the present invention provides a light emitting diode including light emitting cells arranged in a matrix between first and second bonding pads, comprising: a substrate having the light emitting cells on an upper surface thereof; A light guide part formed on the substrate, the light guide part collecting light incident to the adjacent light emitting cells through an outer peripheral part and guiding the collected light through an inner peripheral part in a predetermined direction; Provide a diode.

Description

Light emitting diode having light guide part and manufacturing method thereof {light emitting diode having light guide part and method for fabricating the same}

1 is a circuit diagram of a light emitting diode according to an embodiment of the present invention.

2 is a plan view of a light emitting diode according to an embodiment of the present invention.

3 is a partial cross-sectional view taken along the line AA ′ of FIG. 2 to illustrate a light emitting diode according to an embodiment of the present invention.

4 is a partial cross-sectional view taken along the line BB ′ of FIG. 2 to illustrate a light emitting diode according to an embodiment of the present invention.

5A is a cross-sectional view of an optical guide unit according to an embodiment of the present invention.

5B is a cross-sectional view of an optical guide unit according to another exemplary embodiment of the present invention.

6 to 9 are cross-sectional views illustrating a method of manufacturing a light emitting diode according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: light emitting diode 20: buffer layer

30: semiconductor layers 31: n-type layer

32: active layer 33: p-type layer

40: transparent electrode layer 50a, 50b: first electrode, second electrode

60a, 60b: electrode pad 70: light reflection prevention layer

100: substrate 200: light emitting cells

300a, 300b: bonding pad 400: metal wiring

500: light guide part 510: outer peripheral part

520: inner peripheral portion 530: groove portion

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode having a light guide portion and a method of manufacturing the same. In particular, in a light emitting diode including light emitting cells arranged in a matrix, light incident on a substrate in a horizontal direction is collected from adjacent light emitting cells. The present invention relates to a light emitting diode having a light guide portion having improved light emission efficiency by a light guide portion guiding to be emitted in a direction, and a method of manufacturing the same.

A light emitting diode is a photoelectric conversion semiconductor device having a structure in which an N-type semiconductor and a P-type semiconductor are bonded to each other, and emit light by recombination of electrons and holes. Such light emitting diodes are widely used as display devices and backlights. In addition, the light emitting diode consumes less power and has a longer lifespan than existing light bulbs or fluorescent lamps, thereby replacing its incandescent lamps and fluorescent lamps, thereby expanding its use area for general lighting.

The light emitting diode is repeatedly turned on and off in accordance with the direction of the current under AC power. Therefore, 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 damaged by reverse current.

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 (A1) "Light-Emitting Device Having Light-Emitting Component" (LIGHT-EMITTING DEVICE HAVING LIGHT- EMITTING ELEMENTS, which was disclosed by SAKAI et. Al.

According to WO 2004/023568 (A1), the LEDs form LED arrays two-dimensionally connected in series with metal wires on an insulating substrate such as a sapphire substrate. These two LED arrays are connected in anti-parallel on the substrate. As a result, the AC power supply causes the arrays to alternately turn on and off each other to emit light.

However, as disclosed in WO 2004/023568 (A1), when using a plurality of light emitting cells arranged in a two-dimensional matrix proceeds in a horizontal direction with respect to the light emitting cells of the light emitted by the light emitting cells As the light is emitted through the other adjacent light emitting cells to the outside there is a problem that the brightness of the light emitted is low.

SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting diode having improved luminous efficiency by including a light guide unit for collecting the light traveling in a horizontal direction with respect to the substrate of the emitted light to the outside.

Another object of the present invention is to provide a light emitting diode in which the light guide portion is regularly and effectively arranged.

Still another object of the present invention is to provide a method of manufacturing the light emitting diode.

According to an aspect of the present invention for achieving the above object, a light emitting diode comprising light emitting cells arranged in a matrix between the first and second bonding pads, comprising: a substrate having the light emitting cells on the upper surface; A light guide part formed on the substrate, the light guide part collecting light incident to the adjacent light emitting cells through an outer peripheral part and guiding the collected light through an inner peripheral part in a predetermined direction; It is a diode.

Preferably, the optical guide part includes an N-type semiconductor layer, an active layer formed on a portion of the N-type semiconductor layer, a P-type semiconductor layer formed on the active layer, and an electrode layer formed on the P-type semiconductor layer, A groove portion having a is formed.

More preferably, the inner circumferential portion is formed to be inclined at a predetermined angle with respect to the substrate.

More preferably, the inner circumferential portion is formed in a direction perpendicular to the substrate.

More preferably, further includes a light reflection prevention layer covering the surface of the light guide portion except for the outer peripheral portion in order to increase the light transmittance of the incident light.

More preferably, the light reflection prevention layer has a thickness of λ / 4n.

More preferably, the light reflection prevention layer is made of any one of SiO ₂ , Al ₂ O ₃ or Si ₃ N ₄ .

According to another aspect of the present invention for achieving the above object, a substrate is prepared, and the semiconductor layer including a buffer layer, an N-type semiconductor layer, an active layer and a P-type semiconductor layer on the substrate and located on the semiconductor layers Forming an electrode layer, patterning the semiconductor layers and the electrode layer to form a semiconductor pattern spaced apart from each other, and forming a plurality of light emitting cells by patterning a portion of the semiconductor pattern; An optical guide part having metal outer lines electrically connected to each other, and patterning the semiconductor pattern, the light guide part having an outer circumferential portion through which light is incident from adjacent light emitting cells and an inner circumference portion guiding the incident light in a predetermined direction. It is a light emitting diode manufacturing method which has a light guide part to form, It is characterized by the above-mentioned.

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

1 is a circuit diagram illustrating a light emitting diode according to an embodiment of the present invention, and FIG. 2 is a plan view illustrating a light emitting diode according to an embodiment of the present invention.

1 and 2, a light emitting diode 1 according to an embodiment of the present invention may include a substrate 100, light emitting cells 200, first and second bonding pads 300a and 300b, Metal wires 400 and light guide parts 500.

The substrate 100 may be formed of a material such as SiC having a higher thermal conductivity than sapphire or sapphire, and a plurality of patterned light emitting cells 200 are formed on the substrate 100.

Each of the light emitting cells 200 has a structure in which an N-type semiconductor layer 31, an active layer 32, and a P-type semiconductor layer 33 are sequentially stacked. The active layer 32 is formed on a portion of the N-type semiconductor layer 31, and a P-type semiconductor layer 33 is formed on the active layer 32. Accordingly, a portion of the upper surface of the N-type semiconductor layer 31 is bonded to the active layer 32, and the remaining portion of the upper surface of the N-type semiconductor layer 31 is exposed to the outside.

As shown in FIGS. 1 and 2, the light emitting cells 200 are arranged in a matrix, for example, in a square matrix, between the first bonding pad 300a and the second bonding pad 300b.

The first and second bonding pads 300a and 300b are pads for connecting the light emitting diode 1 to an external power source. The first and second bonding pads 300a and 300b may be connected to an external power source through bonding wires (not shown).

The metal wires 400 electrically connect the light emitting cells 200. The metal wires 400 connect the first electrode 50a of one light emitting cell 200 and the second electrode 50b of another light emitting cell 200 adjacent to the light emitting cell 200 to emit adjacent light. The P-type semiconductor layer 33 and the N-type semiconductor layer 31 of the cells 200 are electrically connected to each other.

The metal wires 400 each of the first electrode 50a and the second electrode 50b of the light emitting cell 200 located at the intersection where the row and the column meet each other, the second of the light emitting cells 200 adjacent thereto. Each of the electrode 50b and the first electrode 50a is electrically connected to the first bonding pad 300a or the second bonding pad 300b.

In particular, the first electrode 50a of the light emitting cell 200 positioned at an intersection point adjacent to two light emitting cells 200 among the light emitting cells 200 is the second electrode (1) of one light emitting cell 200 adjacent thereto. 50b) and the second electrode 50b is electrically connected to the first electrode 50a of the other adjacent light emitting cell 200.

In addition, the first electrode 50a of the light emitting cell 200 positioned at an intersection point adjacent to three light emitting cells 200 among the light emitting cells 200 is a second electrode (1) of one adjacent light emitting cell 200 ( 50b) and the second electrode 50b is electrically connected to the first electrode 50a of two other adjacent light emitting cells 200, or the first electrode 50a of the corresponding light emitting cell 200 is The second electrode 50b of the two adjacent light emitting cells 200 is electrically connected, and the second electrode 50b is electrically connected to the first electrode 50a of the other adjacent light emitting cell 200.

In addition, the first electrode 50a of the light emitting cell 200 positioned at an intersection point adjacent to four light emitting cells 200 among the light emitting cells 200 is a second electrode of the two adjacent light emitting cells 200 ( 50b) is electrically connected, and the second electrode 50b is electrically connected to the first electrode 50a of the two other adjacent light emitting cells 200.

The light guide part 500 is located in an area formed of four light emitting cells 200 positioned at the adjacent intersections, and concentrates the light emitted from the adjacent light emitting cells 200 to guide the light emitted to the outside. Play a role. In particular, as shown in FIGS. 1 and 2, the light guide unit 500 is regularly arranged at predetermined intervals to simplify the manufacturing process of the light emitting diode 1 and reduce manufacturing costs. desirable.

The light guide part 500 may have a circular shape as shown in FIG. 2, but may have an angular shape such as a square or a pentagon.

3 is a partial cross-sectional view taken along the line AA ′ of FIG. 2 to illustrate a light emitting diode according to an embodiment of the present invention.

Referring to FIG. 3, light emitting cells 200 spaced apart from each other are disposed on a substrate 100. Each of the light emitting cells 200 includes an N-type semiconductor layer 31, a P-type semiconductor layer 33 and an N-type semiconductor layer 31 positioned on a portion of the N-type semiconductor layer 31. An active layer 32 is interposed between the P-type semiconductor layers 33.

Here, the N-type semiconductor layer 31 serves as the first electrode 50a. On the other hand, the second electrode 50b is formed on the P-type semiconductor layer 33. The second electrode 50b may be a transparent electrode layer 40 through which light can pass.

The light emitting cells 200 may be formed by forming each of the semiconductor layers 30 and the transparent electrode layer 40 on the substrate 100 and then patterning the same using a photolithography and an etching process.

An electrode pad 60a may be formed on one region of the N-type semiconductor layer 31, and an electrode pad 60b may be formed on the second electrode 40. The electrode pads 60a and 60b may be formed at a desired position by using a lift-off method.

The metal wires 400 may be formed together using an air-bridge process or a step-cover process.

4 is a partial cross-sectional view taken along the line B-B ′ of FIG. 2 to illustrate a light emitting diode according to an embodiment of the present invention.

Referring to FIG. 4, light emitting cells 200 spaced apart from each other are positioned on a substrate 100, and an optical guide part 500 is positioned between the light emitting cells 200.

The light emitting cells 200 have the same configuration as the light emitting cells 200 shown in FIG. 3.

After forming the semiconductor layers 30 and the transparent electrode layer 40, the optical guide part 500 etches the center part to expose the substrate 100 so as to form the groove part 530 having the inner circumferential part 520. Form. The light guide part 500 may be etched such that the inner circumferential part 520 is inclined with respect to the substrate 100 as shown in FIG. 5A or perpendicular to the substrate 100 as shown in FIG. 5B. Can be. The light guide part 500 collects the light emitted from adjacent light emitting cells 200 through the outer circumferential part 510 and emits the light in a predetermined direction, for example, perpendicular to the substrate 100. It plays a role.

When arranging the light emitting cells 200 in rows and columns, for example, a two-dimensional square, when only the light emitting cells 200 are disposed without the light guide part 500, the light emitting cells 200 are emitted from the light emitting cells 200. Among the lights, the light traveling in the horizontal direction with respect to the substrate 100 passes through adjacent light emitting cells 200, and the luminance thereof decreases, thereby lowering the overall luminous efficiency of the light emitting diode 1. Accordingly, as shown in FIGS. 1 and 2, the light guide unit 500 is disposed at a predetermined interval to emit light incident from the light emitting cells 200 adjacent to the light guide unit 500 in a horizontal direction. The light emitting efficiency of the light emitting diode 1 is improved by collecting and emitting the light in the vertical direction.

In addition, the light reflection prevention layer 70 may be formed on the light guide part 500 by coating a light reflection prevention material for increasing the light transmittance of the light guide part 500. The thickness of the light reflection prevention layer is preferably λ / 4n. Is the wavelength of light incident from the adjacent light emitting cells, and n is the refractive index of the light reflection preventing material. The anti-reflective material is preferably a material having a refractive index of 1.3 to 1.7, and may be, for example, SiO ₂ , Al ₂ O _3, or Si ₃ N ₄ . The light reflection prevention layer 70 may be formed by sputtering the light reflection material on the light guide part 500.

Hereinafter, a light emitting diode manufacturing method according to the present embodiments will be described in detail.

6 to 9 are cross-sectional views illustrating a method of manufacturing a light emitting diode according to an embodiment of the present invention.

Referring to FIG. 6, a buffer layer 20 is formed on a substrate 100, and an N-type semiconductor layer 31, an active layer 32, a P-type semiconductor layer 33, and a transparent electrode layer are formed on the buffer layer 20. 40 are formed in sequence.

The buffer layer 20 and the semiconductor layers 30 may be formed using metal organic chemical vapor deposition (MOCVD), molecular beam growth (MBE) or vapor phase growth (HVPE). In addition, the semiconductor layers 30 may be continuously formed in the same process chamber. The buffer layer 20 may be formed of an insulating material film, such as an AlN or semi-insulating GaN layer, but may be formed of a conductive material film, for example, an N-type GaN layer.

The transparent electrode layer 40 may be a transparent electrode layer formed of Ni / Au or indium tin oxide (ITO).

Referring to FIG. 7, after the transparent electrode layer 40 is formed, the semiconductor patterns 30 are spaced apart from each other by patterning the semiconductor layers 30 and the transparent electrode layer 40 by using a photolithography and etching process. 200, 500).

Referring to FIG. 8, after the semiconductor patterns 200 and 500 are formed, the P-type semiconductor layer 33 and the active layer of the semiconductor patterns to be made of the light emitting cells 200 are photographed and etched using a photolithography process. The 32 is patterned to expose a portion of the upper portion of the N-type semiconductor layer 31.

Thereafter, patterning is performed on semiconductor patterns to be manufactured by the light guide part 500 of the semiconductor patterns so that the light emits the outer circumferential part of the light emitting cells 200 and the incident light is emitted in a predetermined direction. An optical guide part 500 having an inner circumference to guide is formed.

Thereafter, an electrode pad 60a is formed on the exposed N-type semiconductor layer 31. The electrode pad 60a may be formed using a lift-off method. Thereafter, the electrode pad 60b and the electrode pad 60a of the adjacent light emitting cell are connected to the metal wires 400. The metal wires 400 may be formed through an air bridge or step cover process.

Referring to FIG. 9, after the light guide part 500 is formed, sputtering a light reflection preventing material on the light guide part 500 to increase the light transmittance of light incident on the light guide part 500. ) To form a light reflection prevention layer 70 covering the surface of the light guide portion except for the outer circumferential portion. The anti-reflective material may be SiO ₂ , Al ₂ O _3, or Si ₃ N ₄ , and the thickness of the anti-reflective layer 70 may be λ / 4n. Here, λ denotes the wavelength of light incident from the adjacent light emitting cell 200, and n denotes the refractive index of the light reflection preventing material.

In the present invention, the optical guide part 500 is described as being formed after the transparent electrode layer 40 is formed. However, the optical guide part 500 may be formed after the semiconductor layers 30 are formed. Of course you can.

The present invention is not limited to the embodiments described above, and various modifications and changes can be made by those skilled in the art, which are included in the spirit and scope of the present invention as defined in the appended claims.

According to the present invention as described above has an effect of providing a light emitting diode having improved luminous efficiency by having a light guide unit for collecting the light traveling in a horizontal direction with respect to the substrate of the emitted light to the outside.

In addition, according to the present invention as described above there is an effect that can provide a light emitting diode in which the light guide portion is regularly and effectively arranged.

In addition, according to the present invention as described above there is an effect that can provide a method for manufacturing the light emitting diode.

Claims (14)

A light emitting diode comprising light emitting cells arranged in a matrix between first and second bonding pads. A substrate having the light emitting cells on an upper surface thereof; An optical guide unit formed on the substrate and configured to collect light incident from the light emitting cells adjacent through the outer circumferential part and to emit the collected light in a predetermined direction through the inner circumferential part; Light-emitting diode having a light guide portion comprising a. The semiconductor device of claim 1, wherein the light guide part comprises an N-type semiconductor layer, an active layer formed on a portion of the N-type semiconductor layer, a P-type semiconductor layer formed on the active layer, and an electrode layer formed on the P-type semiconductor layer. A light emitting diode having a light guide portion, characterized in that the groove portion having an inner peripheral portion is formed. The light emitting diode of claim 1, wherein the inner circumferential portion is formed to be inclined at a predetermined angle with respect to the substrate. The light emitting diode of claim 1, wherein the inner circumferential portion is formed in a direction perpendicular to the substrate. The light emitting diode of claim 1, further comprising a light reflection prevention layer covering a surface of the light guide part except the outer circumference to increase the light transmittance of the incident light. The light emitting diode of claim 5, wherein the light reflection prevention layer has a thickness of? / 4n. (Λ is the wavelength of light incident from the adjacent light emitting cell, n is the refractive index of the light reflection preventing material) The light emitting diode of claim 5, wherein the light reflection prevention layer is made of any one of SiO ₂ , Al ₂ O _3, or Si ₃ N ₄ . Prepare the substrate, Forming semiconductor layers including a buffer layer, an N-type semiconductor layer, an active layer, and a P-type semiconductor layer on the substrate, and electrode layers positioned on the semiconductor layers, Patterning the semiconductor layers and the electrode layers to form semiconductor patterns spaced apart from each other and arranged in a matrix; Patterning a portion of the semiconductor pattern to form a plurality of light emitting cells and forming metal wires electrically connecting the light emitting cells; Patterning the semiconductor pattern to form an optical guide having an outer circumferential portion to which light is incident from adjacent light emitting cells and an inner circumferential portion to guide the incident light in a predetermined direction; Method of manufacturing light emitting diodes. The semiconductor device of claim 8, wherein the light guide part comprises an N-type semiconductor layer, an active layer formed on a portion of the N-type semiconductor layer, a P-type semiconductor layer formed on the active layer, and an electrode layer formed on the P-type semiconductor layer. A light emitting diode manufacturing method having a light guide portion, characterized in that a groove portion having an inner circumference is formed. The method of claim 8, wherein the inner circumferential portion is formed to be inclined at a predetermined angle with respect to the substrate. The method of claim 8, wherein the inner circumferential portion is formed in a direction perpendicular to the substrate. The light emitting diode manufacturing method of claim 8, further comprising a light reflection prevention layer covering a surface of the light guide part except the outer circumference to increase the light transmittance of the incident light. The method of claim 12, wherein the light reflection prevention layer has a thickness of λ / 4n. (Λ is the wavelength of light incident from the adjacent light emitting cell, n is the refractive index of the light reflection preventing material) The method of claim 12, wherein the anti-reflective layer is formed of any one of SiO ₂ , Al ₂ O _3, or Si ₃ N ₄ .

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