KR20080088140A - Heat-sink board and light emitting diode having the same - Google Patents

Abstract

A heat-radiating substrate and a light emitting element including the same are provided to enhance heat-radiating performance by attaching or coating a carbon complex on a base plate. A heat-radiating substrate(100) includes a base plate(110) and a carbon complex(130). The carbon complex is attached or coated on one surface of the base plate. The carbon complex includes one of a carbon nano tube sheet, a carbon sheet, and a carbon paint. A heat-conducting coating layer is formed between the base plate and the carbon complex. A light emitting chip(240) is mounted on the other surface of the base plate. A heat slug is formed between the base plate and the light emitting chip.

Description

Heat dissipation substrate and light emitting device including the same {HEAT-SINK BOARD AND LIGHT EMITTING DIODE HAVING THE SAME}

1 is a schematic perspective view of a light emitting device according to a first embodiment of the present invention;

FIG. 2 is a schematic cross sectional view taken on line A-A in FIG. 1; FIG.

3 is a schematic cross-sectional view of a light emitting device according to a modification of the first embodiment of the present invention;

4 is a schematic perspective view of a light emitting device according to a second embodiment of the present invention;

5 is a schematic cross-sectional view taken on the line B-B in FIG.

<Explanation of symbols for main parts of the drawings>

100: substrate 110: base plate

120: thermal conductive coating layer 130: carbon composite

140: lead pattern 200: heat slug

220: housing 240: light emitting chip

260: lead frame 280: wiring

300: molding part

The present invention relates to a substrate and a light emitting device including the same, and more particularly, to a high-efficiency heat dissipation substrate having a carbon composite and a light emitting device including the same.

A light emitting diode (LED) refers to a device that generates a small number of carriers (electrons or holes) injected using a P-N junction structure of a compound semiconductor, and emits predetermined light by recombination thereof. The light emitting device using the light emitting diode as described above has a small power consumption and a lifetime of several to several tens of times compared to a conventional light bulb or a fluorescent lamp, and is superior in terms of power consumption reduction and durability. In the light emitting device package according to the related art, the light emitting device in which the light emitting diode is mounted is mounted on the substrate.

However, as the technology of the light emitting diodes, that is, the light emitting chips as described above, the brightness of the light emitting devices is also getting brighter. Since the brightness of the light emitting chip is proportional to the current, more current is required to make the light emitting chip brighter. However, the light emitting device package according to the related art, in which a separate heat dissipation structure is not formed, discharges most of the heat generated during the operation of the light emitting chip through the substrate. However, in the case of using a light emitting chip such as a high power power chip as the light emitting chip, there is a limit in the area of the substrate to radiate heat only by the substrate. That is, the higher the current is applied, the more the light emitting chip emits more heat, and thus there is a problem in that the light emitting chip is damaged and its life is reduced.

In addition, in order to solve this problem, metal vias such as copper (Cu) are bonded to the substrate, but the substrate is not only a cumbersome work process but also a very complicated structure. Moreover, since the substrate having such a structure cannot exhibit the thermal spreading effect of the carbon composite material, the heat dissipation performance is limited.

An object of the present invention is to solve the problems of the prior art described above, to provide a high-efficiency heat dissipation substrate and a light emitting device including the same having a simple structure and can be easily manufactured.

In order to achieve the above object, the present invention provides a heat dissipation substrate comprising a base plate and a carbon composite bonded or coated to one surface of the base plate.

In this case, the carbon composite material may include at least one of a carbon nanotube sheet, a carbon sheet, and a carbon paint, and a thermally conductive coating layer may be formed between the base plate and the carbon composite material.

The present invention also provides a light emitting device comprising a heat dissipation substrate on which one side of the base plate is bonded or coated with a carbon composite, and a light emitting chip mounted on the other side of the base plate.

In this case, a heat slug provided between the base plate and the light emitting chip may be further included, and a carbon composite may also be formed between the heat slug and the base plate.

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

However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Like reference numerals in the drawings refer to like elements.

1 is a schematic perspective view of a light emitting device according to a first embodiment of the present invention, FIG. 2 is a schematic cross-sectional view taken on line AA of FIG. 1, and FIG. 3 is a view of a light emitting device according to a modification of the first embodiment of the present invention. It is a schematic cross section.

As shown in FIGS. 1 and 2, the light emitting device according to the first exemplary embodiment of the present invention may include a substrate 100 having a base plate 110 and a carbon composite material 130, and on the substrate 100. It includes a light emitting chip 240 mounted. In this case, the light emitting device according to the present embodiment may further include a molding part (not shown) encapsulating the light emitting chip 240.

The substrate 100 supports the light emitting chip 240 and quickly discharges heat generated by the light emitting chip 240 to the outside. The base plate 110 and the carbon composite formed on one surface of the base plate 110 are provided. 130.

The base plate 110 is for supporting the light emitting chip 240 and applying power, and the base plate 110 may have a lead pattern 140 for applying external power to the light emitting chip 240. The lead pattern 140 may be connected to the electrode of the light emitting chip 240 by a predetermined wiring 280. FR4, a metal core printed circuit board (MCPCB), BT-Resin, or the like may be used as the base plate 110. In the present embodiment, a substrate made of FR4 is used.

Of course, the base plate 110 may be a housing in the form of a substrate. That is, the base plate 110 may be a housing in the form of a substrate made of a resin such as polyphthalamid (PPA) or liquid crystal polymer (LCP).

The carbon composite 130 is for quickly discharging heat transferred from the light emitting chip 240 to the base plate 110 to the outside, and is formed on one surface of the base plate 110. Of course, the carbon composite 130 may be formed between one surface of the base plate 100 and the light emitting chip 240 and the base plate 110, respectively. In this case, the carbon composite 130 may use a carbon nanotube sheet or a carbon sheet manufactured in the form of a sheet. However, the present invention is not limited thereto, and the carbon composite material 130 may be in the form of a paint in which carbon powder is mixed with a predetermined paint. In this case, the carbon composite sheet 130 in the form of a sheet may be bonded to one surface of the base plate 110 using an adhesive member (not shown), and the carbon composite sheet 130 in the form of paint may be coated or sprayed on the base plate. It may be formed on one surface of the (110). In addition, by incorporating a thin carbon composite (CNT) in the carbon composite sheet to improve the heat transfer coefficient (heat transfer coefficient) can be maximized heat dissipation performance.

Table 1 measures the maximum value of the heat generated during operation of the light emitting device according to the prior art and the light emitting device according to the present embodiment does not form a carbon composite. In this case, the light emitting device according to the prior art used a FR4 substrate as a substrate, the light emitting device according to the present embodiment used a FR4 base plate as a base plate, the light emitting chip used a light emitting chip of 1W. In addition, when measuring the maximum value of the heat generated by the light emitting device, the ambient temperature was measured at room temperature (about 25 degrees Celsius), the maximum temperature (Tmax) of the light emitting device is a light emitting chip junction temperature value measured directly from the light emitting chip.

<Table 1>

division Tmax (℃) Light emitting chip 150 Light emitting chip + FR4 138 Light Emitting Chip + FR4 + Carbon Composite 73.5

Referring to Table 1, when only the light emitting chip is driven without using the substrate, the light emitting chip junction temperature is 150 degrees Celsius. When such a light emitting chip is mounted on an FR4 substrate as in the prior art, the maximum temperature of the light emitting chip is 138 degrees Celsius, and when the light emitting chip is mounted on an FR4 substrate having a carbon composite, the maximum temperature of the light emitting chip is It is 73.5 degrees Celsius. Thus, when the same FR4 substrate is used, the present invention in which the carbon composite is formed shows that the maximum temperature of the light emitting chip is 64.5 degrees Celsius lower than that of the light emitting device according to the prior art.

As described above, the light emitting device according to the present invention can quickly discharge heat generated from the light emitting chip 240 to the outside using the substrate 100 on which the carbon composite 130 is formed, thereby providing a high output light emitting device. can do. In addition, the light emitting device according to the present invention forms a carbon composite 130 on one surface of the base plate 110 without processing the base plate 110, so the structure is not complicated and the manufacturing process is simple.

In this embodiment, the base plate of a single layer has been described as an example, but is not limited thereto. The base plate may be a multilayer of two or more layers. That is, a double-sided substrate having lead patterns formed on one surface and the other surface of the base plate may be used as the base plate, and a substrate formed of multiple layers or more may be used as the base plate.

In this case, as shown in FIG. 3, when the substrate 100 having two or more layers is used as the base plate 110, the insulation and the lead pattern are prevented from being oxidized between the base plate 110 and the carbon composite 130 and the base plate. In order to improve the bonding property of the 110 and the carbon composite 130, it is effective to form a thermally conductive coating layer, for example, a ceramic coating layer. Of course, such a thermally conductive coating layer may be formed to improve the bonding properties even when using a single base plate.

Meanwhile, the light emitting chip 240 uses a phenomenon in which the light emitting chip 240 emits light by recombination of minority carriers (electrons or holes) as a compound semiconductor stacked structure having a p-n junction structure. The light emitting chip 240 may include first and second semiconductor layers (not shown) and active layers (not shown) formed between the first and second semiconductor layers. In this embodiment, the first semiconductor layer is a P-type semiconductor layer, and the second semiconductor layer is an N-type semiconductor layer. In addition, a P-type electrode (not shown) is formed on one side of the upper surface of the light emitting chip 240, that is, a P-type semiconductor layer, and an N-type surface on the other side of the upper surface of the light emitting chip 240, that is, an N-type semiconductor layer. An electrode (not shown) is formed. In this case, the N-type electrode and the P-type electrode are connected to the lead pattern 140 including the first and second lead patterns 140a and 140b, and the N-type electrode is in contact with the first lead pattern 140a, The P-type electrode may be electrically connected to the second lead pattern 140b by the wiring 280. However, the present invention is not limited thereto, and the light emitting chip 240 according to the present invention may use a vertical light emitting chip in addition to the horizontal light emitting chip 240 as described above, and may use various types of light emitting chips emitting visible light or ultraviolet light. Can be used. Of course, it is also possible to use a phosphor for converting such a light emitting chip into light of a specific wavelength. Meanwhile, in the present exemplary embodiment, the light emitting chip 240 is mounted on the first lead pattern 140 as an example. However, the present invention is not limited thereto, and the light emitting chip 240 includes the second lead pattern 140. It may also be mounted on the top. Of course, the light emitting chip 240 may be mounted on the base plate 110 to connect the light emitting chip 240 and the first and second lead patterns with two wires.

The wire 280 is for electrically connecting the light emitting chip 240 and the second lead pattern 140b and may be formed of gold (Au), aluminum (Al), or the like through a process such as a wire bonding process. .

The molding part encapsulates the light emitting chip 240 and fixes the wiring 280 connected to the light emitting chip 240. Since the molding part transmits the light emitted from the light emitting chip 240 to the outside, an epoxy resin is usually used. Or it may be formed of a transparent resin such as silicone resin.

In addition, the light emitting device according to the present invention may further include a diffusion agent (not shown) to uniformly emit light by diffusing light emitted from the light emitting chip 240 by scattering in the molding part. As the diffusion agent, barium titanate, titanium oxide, aluminum oxide, silicon oxide, or the like may be used. In addition, the molding unit may further include a phosphor (not shown). The phosphor absorbs a part of the light emitted from the light emitting chip 240 and emits light having a wavelength different from that of the absorbed light. The phosphor is composed of active ions in which impurities are mixed at appropriate positions of the host crystal. The role of the active ions determines the emission color by determining the energy level involved in the emission process, the emission color is determined by the energy gap between the ground state and the excited state of the active ion in the crystal structure.

Next, a light emitting device according to a second exemplary embodiment of the present invention will be described with reference to the accompanying drawings. Duplicated descriptions of the first embodiment of the present invention described above will be omitted or briefly described.

4 is a schematic perspective view of a light emitting device according to a second embodiment of the present invention, and FIG. 5 is a schematic cross-sectional view taken on line B-B of FIG. 4.

As shown in FIG. 4 and FIG. 5, the light emitting device according to the second exemplary embodiment of the present invention includes a substrate 100 having a base plate 110 and a carbon composite material 130, and on the substrate 100. The formed heat slug 200 and the light emitting chip 240 mounted on the heat slug 200 are included. In this case, the light emitting device according to the present embodiment may further include a housing 220 mounted on the periphery of the heat slug 200 and a molding part 300 encapsulating the light emitting chip 240. In addition, a lead pattern (not shown) is formed on the substrate 100 according to the present embodiment, and the lead pattern and the light emitting chip 240 may be electrically connected by the lead frame 260 and the wiring 280.

The heat slug 200 absorbs heat generated from the light emitting chip 240 and transmits the heat slug to the substrate 100. The heat slug 200 may use a material having a high heat transfer rate, for example, a metal material. The heat slug 200 according to the present embodiment has a cylindrical shape, and grooves are formed along the outer circumference thereof so that the housing 220 mounted on the outside thereof may be firmly fixed to the heat slug 200. . The overall shape of the heat slug 200 is not limited to a cylindrical shape but may have various shapes such as an elliptic cylinder and a polygonal pillar. At this time, the heat slug 200 is effective that the light emitting chip 240 has a larger area than the mounting surface in contact with the light emitting chip 240 and the base plate 110.

The substrate 100 supports the heat slug 200 formed on one surface and rapidly transfers heat generated by the light emitting chip 240 and transferred to the heat slug 200 to the outside, the base plate 110, It includes a carbon composite 130 formed on the base plate 110.

The carbon composite 130 is for quickly discharging heat transferred from the light emitting chip 240 to the base plate 110 to the outside. In this embodiment, the carbon composite 130 is formed between the heat slug 200 and the base plate 110. The first carbon composite material 130a and the second carbon composite material 130b formed on the surface of the base plate 110 facing the first carbon composite material 130 are included.

The light emitting device according to the present embodiment includes a heat slug 200 between the light emitting chip 240 and the first carbon composite material 130a so that heat generated from the light emitting chip 240 has a heat dissipation area than that of the light emitting chip 240. To be transferred to this wide heat slug 200. In addition, the heat slug 200 having a large heat dissipation area may transmit more heat to the first carbon composite material 130a, and the heat transferred to the first carbon composite material 130a may be the base plate 110 and the second material. It is discharged to the outside through the carbon composite (130b). In this case, the first carbon composite material 130a may be omitted.

The housing 220 is for fixing the lead frame 260, and may be mounted on an outer circumference of the heat slug 200. In this case, an opening is formed at a side of the housing 220, and the lead frame 260 may be mounted and fixed to the opening.

In addition, the housing 300 is a material having high thermal conductivity, for example, liquid crystal polymer (LCP), thermoplastic polyimide (TPI), polyether imide (Poly Ether Imide) PEI), Poly Ether Sulfone (PES), Poly Sulphone (PSU), Polyamide 6T (PA6T), Thermally Conductive Liquid Crystal Polymer (TCLCP) Can be used. However, the material is not limited thereto, and any material may be used as long as it has a strength sufficient to fix the lead frame 260 and has a high thermal conductivity so as to quickly discharge heat generated from the light emitting chip 240 to the outside. Can be used. Of course, the housing 300 may use a material having a low thermal conductivity so that the user is not burned by the heat slug 200 having a high temperature because the heat generated by the light emitting chip 240 is directly transmitted.

The lead frame 260 is for applying external power to the light emitting chip 240, and is inserted into and fixed to the first lead frame 260a inserted into one opening of the housing 220 and the other opening of the housing 220. A fixed second lead frame 260b is included. At this time, each of the first lead frame 260a and the second lead frame 260b is connected to the light emitting chip 240 and the wiring 280 and the lead pattern 140 formed on the other side of the base plate 110. And can be connected and fixed by soldering or the like.

As described above, the light emitting device according to the present exemplary embodiment may further include a heat slug 200 having a large heat dissipation area between the light emitting chip 240 and the base plate 110 to further increase heat dissipation performance. In addition, by forming a carbon composite between the heat slug 200 and the base plate 110 can maximize the heat dissipation performance.

Although described above with reference to the drawings and embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit of the invention described in the claims below. I can understand.

For example, in the illustrated embodiment, a substrate or a substrate in which a carbon composite is formed on one surface of a housing in the form of a substrate has been described as an example. However, the present invention is not limited thereto, and the present invention is not limited thereto. It can be applied to all light emitting devices that can use the substrate on which the composite is formed, for example, a light emitting device for a backlight unit in which a plurality of light emitting chips are arranged.

As described above, the present invention can provide a high-efficiency heat dissipation substrate and a light emitting device including the same, which can be easily manufactured by attaching or coating a carbon composite to a base plate.

Claims (6)

With base plate, A heat radiation substrate comprising a carbon composite bonded or coated on one surface of the base plate. The method according to claim 1, The carbon composite material is a heat radiation substrate comprising at least one of carbon nanotube sheet, carbon sheet, carbon coating. The method according to claim 1 or 2, A heat dissipation substrate further comprising a thermally conductive coating layer formed between the base plate and the carbon composite. A heat radiation substrate having a carbon composite bonded or coated to one surface of the base plate, Light emitting device comprising a light emitting chip mounted on the other surface of the base plate. The method according to claim 4, Light emitting element further comprises a heat slug provided between the base plate and the light emitting chip. The method according to claim 5, Light emitting device further comprises a carbon composite formed between the heat slug and the base plate.

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