WO2008082098A1

WO2008082098A1 - Light emitting diode package

Info

Publication number: WO2008082098A1
Application number: PCT/KR2007/006465
Authority: WO
Inventors: Byoung Ki Pyo
Original assignee: Seoul Semiconductor Co Ltd
Current assignee: Seoul Semiconductor Co Ltd
Priority date: 2006-12-28
Filing date: 2007-12-12
Publication date: 2008-07-10
Anticipated expiration: 2009-06-28
Also published as: KR100788265B1

Abstract

The present invention provides a light emitting diode (LED) package, which comprises a heat transfer slug formed of a conductive material; a plurality of submount substrates formed of an in sulative material, each of the submount substrates having a conductive layer formed thereon and being mounted on the heat transfer slug; a plurality of vertical light emitting devices mounted on the conductive layers of the respective submount substrates, each of the vertical light emitting devices having upper and lower electrodes formed on upper and lower portions thereof, respectively; and a plurality of power supply leads for respectively supplying power to the conductive layers of the submount substrates electrically connected to the lower electrodes of the vertical light emitting devices and to the upper electrodes of the vertical light emitting devices through wire bonding.

Description

Description LIGHT EMITTING DIODE PACKAGE

Technical Field

[1] The present invention relates to a light emitting diode package, and more particularly, to a light emitting diode package, wherein a plurality of vertical light emitting devices are disposed on a heat transfer slug using submount substrates and the power supplied to the respective vertical light emitting devices is individually controlled, so that light of various colors can be emitted. Background Art

[2] A conventional full-color, high-power light emitting diode (LED) package technique may be implemented using vertical red, green and blue LEDs that are referred to as one-bonding light emitting devices.

[3] When vertical light emitting devices are used as all of the red, green and blue LEDs, the red, green and blue LEDs are die -bonded to one heat transfer structure, and four terminals are used through wire bonding. At this time, one of the four terminals is a cathode or anode.

[4] In this case, in order for LED users to freely drive red, green and blue colors, there is a problem in that a circuit may be complicated.

[5] Alternatively, the conventional full-color, high-power LED package technique may be implemented using a one-bonding or two-bonding red LED and two-bonding green and blue LEDs.

[6] In this case, an LED package is configured by die-bonding red, green and blue

LEDs to one heat sink structure, and wire -bonding four terminals including one common terminal or six terminals provided in the respective LEDs in pairs.

[7] However, as a two-bonding LED is generally fabricated based on a sapphire substrate, heat dissipation efficiency is lowered, and an additional zener diode should be provided since green and blue LEDs grown on the sapphire substrate are vulnerable to static electricity. If a zener diode is provided to prevent static electricity, manufacturing costs are increased, and its process also becomes complicated. Disclosure of Invention

Technical Problem

[8] The present invention is conceived to solve the aforementioned problems. Accordingly, an object of the present invention is to provide an LED package having a plurality of vertical light emitting devices that can be individually driven. Technical Solution

[9] According to an aspect of the present invention, there is provided an LED package, which comprises a heat transfer slug formed of a conductive material; a plurality of submount substrates formed of an insulative material, each of the submount substrates having a conductive layer formed thereon and being mounted on the heat transfer slug; a plurality of vertical light emitting devices mounted on the conductive layers of the respective submount substrates, each of the vertical light emitting devices having upper and lower electrodes formed on upper and lower portions thereof, respectively; and a plurality of power supply leads for respectively supplying power to the conductive layers of the submount substrates electrically connected to the lower electrodes of the vertical light emitting devices and to the upper electrodes of the vertical light emitting devices through wire bonding.

[10] Preferably, the power supply leads may be provided in pairs in the respective submount substrates.

[11] Preferably, the plurality of vertical light emitting devices may be a plurality of

LEDs emitting lights of different colors.

Advantageous Effects

[12] According to the present invention, it is possible to fabricate a full-color LED package, wherein a plurality of vertical light emitting devices are arranged on a heat transfer slug using submount substrates and power supplied to the respective vertical light emitting devices is individually controlled, so that light of various colors can be emitted.

[13] Further, it is possible to fabricate a full-color, high-power LED package, wherein a vertical light emitting device with relatively high heat dissipation efficiency as compared with a two-bonding light emitting device is used as a light emitting device in implementing a full-color LED package, thereby enhancing thermal stability and thus improving optical power.

[14] Furthermore, it is possible to fabricate a full-color, high-power LED package, wherein a vertical light emitting device relatively durable to static electricity as compared with a two-bonding light emitting device is used as a light emitting device in implementing a full-color high-power LED package, thereby enhancing electrical stability and thus expanding a lifespan. Brief Description of the Drawings

[15] Fig. 1 is a view showing a submount substrate on which a vertical light emitting device is mounted according to an embodiment of the present invention.

[16] Fig. 2 is a view showing the configuration of a light emitting diode package according to an embodiment of the present invention.

[17] <Explanation of Reference Numerals for Major Portions Shown in Drawings>

[18] 1, 2, 3: Vertical light emitting device Ia: Upper electrode [19] Ib: Lower electrode 10, 20, 30: Submount substrate

[20] 11: Substrate layer 12: Conductive layer

[21] 13: Bonding pad 40: Heat transfer slug

[22] 51 - 56: Power supply lead 70: Wire

Best Mode for Carrying Out the Invention

[23] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided only for illustrative purposes so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the following embodiments but may be implemented in other forms. In the drawings, the widths, lengths, thicknesses and the like of elements are exaggerated for convenience of illustration. Like reference numerals indicate like elements throughout the specification and drawings.

[24] Fig. 1 is a view showing a submount substrate on which a vertical light emitting device is mounted according to an embodiment of the present invention.

[25] Referring to Fig. 1, a vertical light emitting device 1 is mounted on a submount substrate 10.

[26] The vertical light emitting device 1 is provided with an upper electrode Ia and a lower electrode Ib and has a light emitting structure of a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer between the upper and lower electrodes.

[27] When the vertical light emitting device is mounted on a high-power light emitting diode (LED) package having a slug and a lead electrode, the vertical light emitting device is generally mounted on a heat transfer slug made of a conductive material. The lower electrode is connected to a power source through the conductive heat transfer slug, and the upper electrode is connected to the lead electrode connected with the power source through wire bonding.

[28] Thus, the vertical light emitting device 1 is referred to as a one-bonding chip, which is distinguished from a two-bonding chip for which two bonding operations are required since two electrodes are formed on the two-bonding chip.

[29] When power is supplied to the upper and lower electrodes, light is generated in the active layer and emitted to the outside of the vertical light emitting device 1.

[30] The vertical light emitting device 1 may be fabricated using various methods.

[31] For example, the vertical light emitting device 1 may be fabricated by sequentially laminating a buffer layer, a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer on a conductive substrate and then forming an upper electrode on the second conductive semiconductor layer. [32] Alternatively, the vertical light emitting device 1 may be fabricated by sequentially laminating a buffer layer, a first conductive semiconductor layer, an active layer and a second conductive semiconductor layer on a substrate, irradiating the substrate with laser to separate the substrate, forming a lower electrode on the first conductive semiconductor layer, and then forming an upper electrode on the second conductive semiconductor layer.

[33] The submount substrate 10 is formed of an insulative material. For example, the submount substrate 10 may be formed of AlN or SiC. In addition, a variety of substrates formed of an insulative material may be used as the submount substrate. Preferably, a substrate with excellent thermal conductivity is used as the submount substrate.

[34] Although the submount substrate 10 is formed in a square shape in this figure, the shape, size and thickness of the submount substrate 10 may be modified in a variety of ways.

[35] A conductive layer 12 with a predetermined thickness is formed on the submount substrate 10.

[36] The conductive layer 12 may be formed of a conductive metal such as Ag, Al, Au,

AuSn, Ni or W.

[37] The submount substrate 10 comprises a substrate layer 11 formed of an insulative material and a conductive layer 12. The vertical light emitting device 1 is mounted on the conductive layer 12. Thus, the lower electrode Ib of the vertical light emitting device 1 is electrically connected to the conductive layer 12.

[38] The conductive layer 12 is electrically connected to a lead electrode connected to an external power source through wire bonding.

[39] A bonding pad 13 is formed on the conductive layer 12. The wire bonding may be directly performed on the conductive layer 12 such that the conductive layer is connected to the lead electrode. However, if the bonding pad 13 is used, the wire bonding between the conductive layer 12 and the lead electrode can be easily and securely performed.

[40] The position and shape of the bonding pad 13 formed on the submount substrate 10 may be modified without limitation.

[41] Although the vertical light emitting device 1 is mounted on the heat transfer slug made of a conductive material while it is mounted on the submount substrate 10, the vertical light emitting device 1 is electrically disconnected from the corresponding heat transfer slug since the substrate layer 11 of the submount substrate 10 is formed of an insulative material.

[42] Fig. 2 is a view showing the configuration of an LED package according to an embodiment of the present invention. [43] Referring to Fig. 2, the LED package according to the embodiment of the present invention comprises submount substrates 10, 20 and 30 on which red, green and blue LEDs 1, 2 and 3 are respectively mounted, a heat transfer slug 40 and power supply leads 51 to 56.

[44] In this figure, a specific housing structure of the LED package is not shown, but only the submount substrates 10, 20 and 30, heat transfer slug 40 and power supply leads 51 to 56 installed in a housing are selectively shown. Here, the housing structure is omitted, and only respective components provided in the housing are selectively shown for the purpose of more easily illustrating the connection relation between the corresponding components. It is a general practice that the respective components shown in this figure are connected and packaged in a housing structure of a predetermined shape.

[45] The submount substrates 10, 20 and 30 are formed of an insulative material, and a conductive layer is formed on each of the submount substrates. The red, green and blue LEDs 1, 2 and 3 are mounted on the conductive layers, respectively.

[46] The red, green and blue LEDs 1, 2 and 3 respectively mounted on the submount substrates 10, 20 and 30 are vertical light emitting devices.

[47] The heat transfer slug 40 is formed of a material with high thermal conductivity, and a conductive material is preferably used.

[48] The power supply leads 51 to 56 are provided in pairs in the respective submount substrates 10, 20 and 30.

[49] Thus, the first and fourth power supply leads 51 and 54 are connected to the first submount substrate 10 on which the red LED 1 is mounted through wires 70, the second and fifth power supply leads 52 and 55 are connected to the second submount substrate 20 on which the green LED 2 is mounted through wires 70, and the third and sixth power supply leads 53 and 56 are connected to the third submount substrate 30 on which the blue LED 3 is mounted through wires 70.

[50] The positions and distances of the first, second and third submount substrates 10, 20 and 30 disposed on the heat transfer slug 40 and spaced apart from one another may be modified without limitation.

[51] Since the red, green and blue LEDs 1, 2 and 3 are respectively mounted on the submount substrates 10, 20 and 30 formed of an inuslative material to be disposed on the heat transfer slug 40, the respective LEDs are electrically disconnected from one another.

[52] In addition, since each pair of the power supply leads 51 to 56 are provided in each of the submount substrates 10, 20 and 30, power can be separately supplied to the respective power supply leads 51 to 56. Accordingly, the red, green and blue LEDs 1, 2 and 3 can be individually operated. [53] For example, if power is supplied only to the first and fourth power supply leads 51 and 54 but is not supplied to the other power supply leads 51, 53, 55 and 56, only the red LED 1 can be operated to emit red light.

[54] Meanwhile, if power is supplied only to the second and fifth power supply leads 52 and 55, but not supplied to the other power supply leads 51, 53, 54 and 56, only the green LED 2 can be operated to emit green light.

[55] Meanwhile, if power is supplied only to the third and sixth power supply leads 53 and 56 but not supplied to the other power supply leads 51, 52, 54 and 55, only the blue LED 3 can be operated to emit blue light.

[56] In addition, if power is appropriately supplied to the first to sixth power supply leads 51 to 56, the red, green and blue LEDs 1, 2 and 3 are operated as a whole to emit white light.

[57] Alternatively, power supplied to the first to sixth power supply leads 51 to 56 is individually controlled to generate light of a desired color.

[58] The present invention is not limited to the aforementioned embodiments, but various modifications and changes can be made thereto by those skilled in the art. The modifications and changes are includes in the spirit and scope of the invention defined by the appended claims.

[59] For example, according to the embodiment of the present invention, the submount substrates are mounted on the heat transfer slug to be spaced apart from one another while the vertical light emitting device is mounted on each of the submount substrates.

[60] However, the submount substrate may be formed as one substrate on a heat transfer slug such that respective vertical light emitting devices are mounted on the one substrate to be electrically spaced apart from one another. That is, it is possible to modify the invention such that when conductive layers are formed on an insulative material, the conductive layers may be formed to be spaced apart from each other, and a vertical light emitting device is mounted on each of the electrically separated conductive layers.

Claims

[1] A light emitting diode (LED) package, comprising: a heat transfer slug formed of a conductive material; a plurality of submount substrates formed of an insulative material, each of the submount substrates having a conductive layer formed thereon and being mounted on the heat transfer slug; a plurality of vertical light emitting devices mounted on the conductive layers of the respective submount substrates, each of the vertical light emitting devices having upper and lower electrodes formed on upper and lower portions thereof, respectively; and a plurality of power supply leads for respectively supplying power to the conductive layers of the submount substrates electrically connected to the lower electrodes of the vertical light emitting devices and to the upper electrodes of the vertical light emitting devices through wire bonding.

[2] The LED package as claimed in claim 1, wherein the power supply leads are provided in pairs in the respective submount substrates.

[3] The LED package as claimed in claim 1, wherein the plurality of vertical light emitting devices are a plurality of LEDs emitting lights of different colors.

[4] The LED package as claimed in claim 1, wherein the submount substrate is formed of AlN or SiC.

[5] The LED package as claimed in claim 1, wherein the conductive layer is formed of at least one selected from a group consisting of Ag, Al, Au, AuSn, Ni and W.

[6] The LED package as claimed in claim 1, wherein the submount substrates are mounted on the heat transfer slug to be spaced apart from one another while the respective vertical light emitting devices are mounted on the submount substrates.

[7] The LED package as claimed in claim 1, wherein the submount substrates are formed as one substrate, and the plurality of vertical light emitting devices are mounted on the one substrate to be electrically spaced apart from one another.