KR20090001037A - Light emitting diode package employing carbon nano tube substrate - Google Patents

Abstract

A light-emitting diode package is provided to improve heat emitting efficiency of a package by perpendicularly transmitting and horizontally dispersing heat generated in a light emitting diode chip through a carbon nanotube substrate having high thermal conductivity. A chip mounting member(M) comprises a mounting surface for setting up a light emitting diode chip and two or more leads which are insulated from each other. A carbon nanotube substrate(23) is located between the mounting surface of the chip mounting member and a light emitting diode chip(25). The carbon nanotube substrate is formed by compression of carbon nanotube powder. The light emitting diode chip is electrically connected the two or more leads. A buffer adhesive(24) is located between the carbon nanotube substrate and the light emitting diode chip. The upper side and lower side of the carbon nanotube substrate are surface-treated in order to have an adhesive property.

Description

LIGHT EMITTING DIODE PACKAGE EMPLOYING CARBON NANO TUBE SUBSTRATE}

1 is a cross-sectional view illustrating a chip type light emitting diode package according to the prior art.

2 is a schematic cross-sectional view illustrating a light emitting diode package according to embodiments of the present invention.

3 is a cross-sectional view for describing a chip type light emitting diode package according to an embodiment of the present invention.

4 is a cross-sectional view for describing a tower light emitting diode package according to another exemplary embodiment of the present invention.

5 is a front view illustrating a side light emitting diode package according to another embodiment of the present invention.

6 is a cross-sectional view for describing a power light emitting diode package according to another embodiment of the present invention.

7 is a cross-sectional view for describing a lamp type LED package according to still another embodiment of the present invention.

The present invention relates to a light emitting diode package, and more particularly to a light emitting diode package employing a carbon nanotube substrate.

LEDs are widely used for indicators, electronic signs, and displays because they can implement colors, and are also used for general lighting because they can implement white light. In addition, the light emitting diode may implement a region other than the visible light region, that is, ultraviolet rays or infrared rays, and thus is used for various purposes such as optical communication. Such light emitting diodes have high efficiency, long life, and eco-friendliness, and the field of using them continues to increase.

Inorganic light emitting diodes such as gallium nitride, gallium arsenide, gallium phosphorus and the like are generally manufactured in chip form and assembled into packages of various structures for protection from the external environment and for specific applications. Light emitting diode packages are known, for example, in the form of chip, top-view, side-view, power and lamp-type light emitting diode packages.

1 is a cross-sectional view illustrating a conventional chip type light emitting diode package 10.

Referring to FIG. 1, the chip type LED package 10 generally includes a printed circuit board 11 on which leads 11a and 11b are printed. The light emitting diode chip 15 is mounted on the printed circuit board 11 and electrically connected to the leads 11a and 11b. For example, the light emitting diode chip 15 is die bonded on the pad region of the lead 11a and electrically connected to the lead 11b by a bonding wire. Meanwhile, the resin molding part 19 covers the light emitting diode chip 15. The resin molding unit 19 may contain a phosphor that converts a wavelength of light emitted from the light emitting diode chip 15. Light of various colors may be implemented by the light emitting diode chip 15 and the phosphor, for example, white light.

In addition, in order to mount the light emitting diode chip 15 on a chip mounting member such as a printed circuit board 11, an adhesive 13 is generally used. The adhesive 13 is generally a polymer material such as epoxy, and may be an insulating epoxy (white epoxy) or a conductive epoxy containing silver (Ag). Epoxy containing silver is conductive unlike the white epoxy, and electrically connects the LED chip 15 to the lead 11a.

On the other hand, during operation of the light emitting diode chip 15, heat is generated in the light emitting diode chip. Heat generated in the light emitting diode chip 15 is discharged to the outside through the resin molding 19 and the printed circuit board 11 around it. However, since the resin molding portion 19 generally has a relatively low thermal conductivity, heat is mainly emitted to the outside through the printed circuit board 11, especially the lid 11a. However, since the adhesive 13 interposed between the light emitting diode chip 15 and the printed circuit board 11 has a relatively low thermal conductivity, heat generated in the light emitting diode chip 15 is transferred to the printed circuit board 11. Interfere with being. Accordingly, the junction temperature of the light emitting diode chip 15 is increased, which results in a decrease in light efficiency and a change in wavelength of emitted light. In addition, when the LED chip is exposed to high heat, the life of the chip is shortened, and the chip may be destroyed by heat.

It is an object of the present invention to provide a light emitting diode package having improved heat dissipation performance.

In order to achieve the above technical problem, the present invention provides a light emitting diode package employing carbon nanotubes. The LED package according to an embodiment of the present invention includes a chip mounting member, at least one LED chip, and a carbon nanotube substrate. The chip mounting member has a mounting surface for mounting the LED chip and includes at least two leads insulated from each other. On the other hand, the carbon nanotube substrate is formed by compressing the carbon nanotube powder, it is interposed between the mounting surface of the chip mounting member and the light emitting diode chip. In addition, the at least one light emitting diode chip is electrically connected to the at least two leads. Accordingly, the heat dissipation performance of the light emitting diode package is improved by adopting a carbon nanotube substrate having a high thermal conductivity.

Here, the "chip mounting member" is a structure having a mounting surface for mounting a light emitting diode chip, the structure is not limited to a specific material or shape. For example, the chip mounting member may include a printed circuit board on which leads are printed in a chip type LED package, a package body having leads in a top or side emitting type LED package, and leads and a heat sink in a power type LED package. It may be a package body having, and may be leads in a lamp type light emitting diode package.

Meanwhile, the "carbon nanotube" powder is short fiber and / or long fiber powder having a diameter of 100 nm or less. Carbon nanotubes have a structure in which a carbon hexagonal network sheet is closed in a cylindrical shape and has a single layer or a multilayer structure. In addition, the carbon nanotubes include a carbon material having a structure of carbon nanotubes partially. Such carbon nanotubes may be manufactured by an arc discharge method, a laser ablation method, a vapor phase growth method, a pyrolysis method, and the like, and may have conductive or semiconducting properties, depending on the structure.

The carbon nanotube substrate may be formed by compressing carbon nanotube powder using a conventional powder compression technique, and may be formed by compressing while applying heat. In general, a technique for producing a carbon nanotube sheet by dispersing the carbon nanotube powder in a matrix such as an organic binder is known, but the thermal conductivity of the carbon nanotube sheet is dependent on the thermal conductivity of the matrix and Because of their dependence, their thermal conductivity is relatively low and uneven. On the contrary, according to the embodiments of the present invention, since the carbon nanotube powder is compressed to form a substrate without using a matrix such as a binder, it is possible to provide a carbon nanotube substrate having a relatively high thermal conductivity and uniformity.

On the other hand, the carbon nanotube substrate has an upper surface and / or a lower surface may be surface-adhesive. Such surface treatment can be carried out, for example, by coating an adhesive or coupling agent on the top and / or bottom surfaces of the carbon nanotube substrate. Accordingly, the carbon nanotube substrate has adhesiveness like a single-sided tape or a double-sided tape.

The lower surface of the carbon nanotube substrate may be attached to the chip mounting member by having an adhesive property. In addition, the upper surface of the carbon nanotube substrate has adhesiveness so that the LED chip may be attached to the carbon nanotube substrate.

Meanwhile, a buffer adhesive may be interposed between the carbon nanotube substrate and the light emitting diode chip. The carbon nanotube substrate according to the embodiments of the present invention is formed by compressing carbon nanotube powder, and may have a tendency to be easily broken or split according to a direction. The buffer adhesive is interposed between the carbon nanotube substrate and the light emitting diode chip to prevent the carbon nanotube substrate from being broken or split.

The buffer adhesive may be a conductive adhesive, for example, silver (Ag) paste.

When the buffer adhesive is conductive and the carbon nanotube substrate is conductive, the light emitting diode chip may be electrically connected to one lead of the chip mounting member through the buffer adhesive and the carbon nanotube substrate.

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

2 is a cross-sectional view illustrating a light emitting diode package according to embodiments of the present invention.

Referring to FIG. 2, the light emitting diode package may include a chip mounting member M, a carbon nanotube substrate 23, and a light emitting diode chip 25, and may further include an adhesive 24. The chip mounting member M has a mounting surface for mounting a chip. The chip mounting member M may be used without any limitation in any material and structure used to mount the LED chip in a conventional LED package. The chip mounting member has leads (not shown) for electrically connecting the LED chip 25 to an external power source, and the LED chip 25 is electrically connected to the leads. Specific examples of the chip mounting member M are described below with reference to FIGS. 3 to 7.

The light emitting diode chip 25 may be formed of a compound semiconductor of gallium nitride, gallium arsenide, and gallium, and may emit light in an ultraviolet to infrared region according to the type of compound semiconductor selected. In particular, the gallium nitride-based light emitting diode chip may emit light in a short wavelength region of ultraviolet to blue light. Since the gallium nitride-based light emitting diode chip emits light of relatively high energy, heat generated during operation is also relatively higher than that of other light emitting diode chips.

The carbon nanotube substrate 23 is formed by compressing (or thermally compressing) carbon nanotube powder and is interposed between the light emitting diode chip and the chip mounting member (M). The carbon nanotube substrate 23 may have a larger area than the light emitting diode chip 25, but is not limited thereto, and may be the same or smaller. The carbon nanotube powder is a nano-sized carbon fiber powder having a diameter of 100 nm or less, and is a short fiber and / or a long fiber powder. Such carbon nanotubes may be manufactured by an arc discharge method, a laser ablation method, a vapor deposition method or a pyrolysis method. The carbon nanotubes may be conductive or semiconductor depending on their structure.

The carbon nanotube substrate 23 may also be adhered to its upper surface or lower surface, or both surfaces thereof. For example, an adhesive or a coupling agent (eg, a silane coupling agent) may be coated on the upper surface and / or the lower surface of the carbon nanotube substrate 23 to have adhesiveness. Accordingly, the carbon nanotube substrate 23 has adhesiveness on at least one side thereof, such as a single sided tape or a double sided tape.

When the lower surface of the carbon nanotube substrate 23 is adhesive, the lower surface is attached to the chip mounting member (M). In addition, when the upper surface thereof is adhesive, the light emitting diode 25 may be attached to the upper surface of the carbon nanotube substrate 23.

Meanwhile, when the carbon nanotube substrate 23 compresses the powder, the carbon nanotubes may be disposed in a vertical or horizontal direction, and when the carbon nanotube substrate 23 is disposed in a specific direction, the carbon nanotube substrate 23 may be external force or It can easily break or split by heat stress. In order to prevent this, the buffer adhesive 24 may be interposed between the light emitting diode chip 25 and the carbon nanotube substrate 23. The buffer adhesive 24 relieves thermal stress applied to the carbon nanotube substrate 23 from the light emitting diode chip 25 and disperses external force applied to the substrate 23 so that the carbon nanotube substrate 23 is split or broken. Prevent it. When the buffer adhesive 24 is used, the upper surface of the carbon nanobute substrate 23 is not required to be surface treated to be adhesive.

As the buffer adhesive 24, a conventional adhesive may be used without particular limitation. In certain embodiments, the buffer adhesive 24 may be a conductive adhesive, for example silver (Ag) paste.

When the buffer adhesive 24 is a conductive adhesive and the carbon nanotube substrate 23 is conductive, the light emitting diode chip 25 is a chip mounting member through the buffer adhesive 24 and the carbon nanotube substrate 23. It can be electrically connected to (M).

The light emitting diode chip 25 may be covered by a resin molding part (not shown), for example, silicon or epoxy. The resin molding protects the LED chip 25 from moisture or external force. In addition, a phosphor for converting at least a portion of the light emitted from the light emitting diode chip 25 may be included in the package. For example, the phosphor may be coated on the light emitting diode chip, contained in the resin molding part, or coated on the resin molding part. Various colors of light may be realized by various combinations of the light emitting diode chip 25 and the phosphor, for example, white light.

The carbon nanotube substrate 23 according to the embodiments of the present invention has a relatively high thermal conductivity in the vertical direction and the horizontal direction compared to the general adhesive. Therefore, heat generated in the light emitting diode chip 25 is dispersed not only in the vertical direction but also in the horizontal direction to reduce the thermal resistance of the heat emitted from the light emitting diode chip 25.

In particular, when the total thicknesses of the carbon nanotube substrate 23 and the buffer adhesive 24 are the same as those of the conventional adhesive, the thermal resistance in the vertical direction can be reduced, thereby further improving the heat dissipation performance of the package. .

Hereinafter, a light emitting diode package according to specific embodiments of the present invention will be described.

3 is a cross-sectional view for describing a chip type light emitting diode package according to an embodiment of the present invention.

Referring to FIG. 3, the chip type light emitting diode package 20 includes a printed circuit board PCB 21 on which leads 21a and 21b are printed, and the printed circuit board 21 is a chip mounting member (see FIG. 2). Corresponds to M). The printed circuit board is not particularly limited, and may be a general PCB or metal-PCB (MPCB) having excellent heat dissipation performance.

At least one LED chip 25 is mounted on the printed circuit board 21 and electrically connected to the leads 21a and 21b. Meanwhile, as described with reference to FIG. 2, a carbon nanotube substrate 23 may be interposed between the light emitting diode chip 25 and the printed circuit board 21. In addition, the buffer adhesive 24 may include carbon nanoparticles. It may be interposed between the tube substrate 23 and the light emitting diode chip 25.

The light emitting diode chip 25 is electrically connected to the pad region of the lead 21a through the conductive buffer adhesive 24 and the carbon nanotube substrate 23 and electrically connected to the lead 21b by a bonding wire. do. Alternatively, the LED chip 25 may be electrically connected to the leads 21a and 21b by two bonding wires, respectively.

Meanwhile, the resin molding part 29 covers the light emitting diode chip 25. The resin molding part 29 may be formed of epoxy or silicon, and may have various shapes according to the directivity angle characteristic of the required light, and may include a phosphor for converting the wavelength of light emitted from the LED chip 25. have.

According to the present embodiment, heat generated in the light emitting diode chip 25 is transferred to the printed circuit board 21 through the carbon nanotube substrate 23 and discharged to the outside. Since carbon nanotubes have a thermal conductivity similar to that of diamond, they have a relatively higher thermal conductivity than conventional adhesives such as epoxy or silver (Ag) epoxy. Therefore, heat generated in the light emitting diode chip can be quickly transferred through the carbon nanotube substrate 23, thereby improving heat dissipation performance. In addition, the carbon nanotube substrate 23 has a relatively high thermal conductivity in the horizontal direction as compared with the conventional adhesive. Accordingly, the carbon nanotube substrate 23 disperses heat generated in the light emitting diode chip 25 in the horizontal direction and discharges the heat to the peripheral resin molding part 29 through the side surface thereof. Accordingly, the heat generated by the LED chip 25 can be quickly dispersed to the surroundings, thereby reducing the thermal resistance to the heat generated by the LED chip 25.

4 is a cross-sectional view illustrating a tower light emitting diode package according to an embodiment of the present invention.

Referring to FIG. 4, in the top LED package, the chip mounting member M is a package body 31 having at least two leads 31a and 31b. The package body 31 has a recess that exposes the leads 31a and 31b, and the sidewall of the recess may be inclined to reflect light. The package body 31 may be formed of a plastic material, such as PPA, in a leadframe having leads 31a, 31b using insert molding techniques. In addition, the package body 31 may be formed by forming a reflective cup made of a plastic material on the printed circuit board as described with reference to FIG. 3.

At least one light emitting diode chip 25 is mounted on the mounting surface of the package body 31 and electrically connected to the leads 31a and 31b. In addition, a carbon nanotube substrate 23 is interposed between the mounting surface of the light emitting diode chip 25 and the package main body 31. In addition, the buffer adhesive 24 includes a carbon nanotube substrate 23 and a light emitting diode chip ( 25). The light emitting diode chip 25 is electrically connected to the lead 31b by a bonding wire and electrically connected to the lead 31a through the conductive buffer adhesive 24 and the carbon nanotube substrate 23, as shown. Can be connected. In addition, the LED chip 25 may be electrically connected to the leads 31a and 31b through bonding wires, respectively.

On the other hand, the resin molding 39 covers the light emitting diode chip 25. The resin molding 39 may be formed of epoxy or silicon, and may be molded into a required shape using a mold die. In addition, the resin encapsulant 35 can fill in the recesses of the package body 31. The resin encapsulant 35 may be formed by using a dispenser and then hardened or formed using a transfer molding technique, and may be formed of an epoxy or silicone resin. Meanwhile, the tower LED package may further include a phosphor positioned on or on the LED chip 25 to wavelength convert at least a portion of the light emitted from the LED chip 25. The phosphor may be contained, for example, in the resin molding part and / or the resin encapsulant 35.

According to the present embodiment, heat generated in the light emitting diode chip 25 is discharged to the outside through the package body 31 or the leads 31a and 31b through the carbon nanotube substrate 23 having high thermal conductivity and is horizontal. Since it is distributed in the direction, heat dissipation performance is improved as compared with the conventional top-shaped LED package.

5 is a front view illustrating a side-view light emitting diode package 40 according to another embodiment of the present invention.

Referring to FIG. 5, in the side-emitting type LED package 40, the chip mounting member M is a package body 41 having leads 41a and 41b. The package body 41 has a recess in which the leads 41a and 41b are exposed. The LED chip 25 is mounted in the recess and electrically connected to the leads 41a and 41b. In this case, a carbon nanotube substrate 23 is interposed between the light emitting diode chip 25 and the bottom surface of the recess, and a buffer adhesive 24 is added to the carbon nanotube substrate 23 and the light emitting diode chip 25. It can be intervened in between. On the other hand, a resin molding portion (not shown) is formed in the groove portion to cover the light emitting diode chip 25.

According to the present embodiment, since the heat generated from the light emitting diode chip 25 is emitted in the vertical direction and the horizontal direction through the carbon nanotube substrate 23 having high thermal conductivity, heat is emitted as compared to the conventional side light emitting diode package. Performance is improved.

6 is a cross-sectional view for describing a power light emitting diode package according to another embodiment of the present invention.

Referring to FIG. 6, in the power type LED package 50, the chip mounting member M is a package body 51 having leads 51a and 51b and a heat sink 51c. The package body 51 has a recess in which the leads 51a and 51b are exposed. The heat sink 51c is exposed to the recess portion. In addition, the heat sink 51c may protrude above the recess. The LED chip 25 is mounted on the heat sink 51c and electrically connected to the leads 51a and 51b. In this case, a carbon nanotube substrate 23 is interposed between the light emitting diode chip 25 and the heat sink 51c, and a buffer adhesive 24 is added to the carbon nanotube substrate 23 and the light emitting diode chip 25. May be intervened).

Meanwhile, the resin molding part 59 may cover the light emitting diode chip 23, and the resin encapsulant 55 may fill the recess. In addition, the package 50 may include a phosphor. The phosphor may be disposed in various forms, and for example, may be contained in the resin encapsulant 55 and / or the resin molding 59.

7 is a cross-sectional view for describing a lamp type LED package 60 according to another embodiment of the present invention.

Referring to FIG. 7, in the lamp type LED package 60, the chip mounting member M may be leads 61a and 61b. The lid 61a may have a recess in an upper portion thereof. The light emitting diode chip 25 is mounted in the recess of the lead 61a and electrically connected to the leads 61a and 61b. In this case, a carbon nanotube substrate 23 is interposed between the light emitting diode chip 25 and the lead 61a, and a buffer adhesive 24 is added to the carbon nanotube substrate 23 and the light emitting diode chip 25. It can be intervened in between.

The LED chip 25 may be electrically connected to the lead 61a through the conductive buffer adhesive 24 and the carbon nanotube substrate 23, and may be electrically connected to the lead 61b by a bonding wire. In addition, the LED chip 25 may be electrically connected to the leads 61a and 61b through bonding wires, respectively.

Meanwhile, the resin encapsulant 65 may encapsulate the light emitting diode chip 25, and the resin molding 69 encapsulates portions of the leads 61a and 61b. In addition, the package 60 may include a phosphor, and the phosphor may be variously disposed as described above. For example, the phosphor may be formed on the LED chip 25 or contained in the resin encapsulant 65 and / or the resin molding part 69.

According to the present embodiment, heat generated in the light emitting diode chip 25 is transmitted in the vertical direction and the horizontal direction through the carbon nanotube substrate 23 having high thermal conductivity and is emitted to the outside. Is improved.

According to embodiments of the present invention, by adopting a carbon nanotube substrate having a relatively high thermal conductivity, heat generated from the light emitting diode chip can be transferred in a vertical direction through the carbon nanotube substrate and can be distributed in a horizontal direction. It can improve heat dissipation performance.

Claims (6)

A chip mounting member having a mounting surface for mounting a light emitting diode chip and including at least two leads insulated from each other; At least one light emitting diode chip; A carbon nanotube substrate interposed between the mounting surface of the chip mounting member and the light emitting diode chip and formed by compressing carbon nanotube powder; The at least one light emitting diode chip is electrically connected to the at least two leads. The method according to claim 1, The carbon nanotube substrate has a bottom surface is surface-treated light emitting diode package. The method according to claim 2, The carbon nanotube substrate has a surface-treated upper surface of the light emitting diode package. The method according to claim 2 or 3, The lower surface or the upper surface of the carbon nanotube substrate is surface-treated by coating an adhesive or coupling agent. The method according to claim 1, The light emitting diode package further comprises a buffer adhesive interposed between the carbon nanotube substrate and the light emitting diode chip. The method according to claim 5, The buffer adhesive is a light emitting diode package, characterized in that the silver (Ag) paste.

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