KR20090100725A - Printed circuit board for high power light emitting diode, and heat dissipation structure of light emitting diode chip using the same - Google Patents

Abstract

PURPOSE: A printed circuit board for a high power light emitting diode and a heat dissipation structure of a light emitting diode chip using the same are provided to improve performance of the light emitting diode by securing thermal reliability. CONSTITUTION: A printed circuit board(24) for a high power light emitting diode includes an insulating layer(24c) and a conductive layer(24a). A circuit is printed on the surface. A part of the conductive layer is exposed on a position arranging a light emitting diode package including a light emitting diode chip(11), a light emitting diode heat sink, and a lead frame(13). A via hole(24b) is formed in the position with the light emitting diode package.

Description

Printed circuit board for high power light emitting diode, and heat dissipation structure of light emitting diode chip using the same}

The present invention relates to a heat dissipation structure of a printed circuit board (PCB) for a high power light emitting diode (LED) and a light emitting diode using the same, and more particularly, to secure high thermal power of a high output light emitting diode. The present invention relates to a printed circuit board for a high output light emitting diode that can improve the performance of a light emitting diode and to be manufactured at low cost, and a heat dissipation structure of the light emitting diode using the same.

Light Emitting Diode (LED) is a diode that emits excess energy as light when the injected electrons and holes recombine, red light emitting diodes using GaAsP, green light emitting diodes using GaP, and InGaN / AlGaN double hetero. and a blue light emitting diode using a double hetero structure. Such light emitting diodes are widely used in various fields such as numeric character display devices, traffic light sensors, light coupling devices, and the like due to their low voltage and low power.

In recent years, high-power LEDs have problems such as brightness degradation, color coordinate shift, and thermal resistance change due to heat generation at junctions.In order to solve these problems, a high thermal conductivity metal PCB (MPCB) is used. I use it.

1 is a view showing a heat dissipation structure of a light emitting diode chip using a conventional MPCB.

As shown in FIG. 1, in the heat dissipation structure 10 of a light emitting diode chip using a conventional MPCB, a heat transfer path in a package of a high power light emitting diode is a light emitting diode heat sink from the light emitting diode chip 11 as a heat source. Heat is transferred to the outside through the heat sink 12 and the lead frame 13. The structure of the MPCB usually forms a conductive layer (for example, copper) 14a on the aluminum base 14, which is arranged to be electrically insulated from the aluminum base 14. In addition, the lead frame 13 and the LED heat sink 12 are electrically insulated. Heat generated by the LED chip 11 is radiated to the outside air through the LED heat sink 12, the conductive layer 14a, and the aluminum base 14. However, due to the high price of metal PCB, there is a problem of increasing the cost of the product when manufacturing a light emitting diode lighting using a high output light emitting diode.

SUMMARY OF THE INVENTION The present invention has been made to solve various problems including the above problems, and an object of the present invention is to secure a thermal output of a high output light emitting diode, thereby improving the performance of the high output light emitting diode and making it possible to manufacture a high output light emitting diode at low cost. It is to provide a heat dissipation structure of a circuit board and a light emitting diode using the same.

The object of the present invention as described above,

A printed circuit board comprising an insulating layer and a conductive layer,

The circuit is printed on the surface

At least a portion of the conductive layer is exposed at the position where the LED package including the LED chip, the LED heat sink, and the lead frame is disposed.

It is achieved by providing a printed circuit board for a high power light emitting diode having at least one via hole penetrating from one surface to the opposite surface at a position where the light emitting diode package is to be disposed.

Here, the via hole is formed on a plane of the printed circuit board at a position outside the position where the light emitting diode chip disposed inside the light emitting diode package is to be disposed so that the position where the light emitting diode chip is to be disposed does not overlap with the position of the via hole. It is preferable not to.

In addition, the cross-sectional area of one via hole occupied on the printed circuit board is preferably smaller than that of the light emitting diode chip.

In addition, the object of the present invention as described above,

A light emitting diode package including a light emitting diode chip; And

A printed circuit board on which a light emitting diode package is disposed, the circuit being printed on a surface thereof;

It is achieved by providing a heat dissipation structure of a light emitting diode chip having one or more via holes formed in a portion of the printed circuit board on which the light emitting diode package is disposed.

Here, the via hole is formed on a plane of the printed circuit board outside the position where the light emitting diode chip disposed inside the light emitting diode package is disposed, so that the position of the light emitting diode chip does not overlap with the position of the via hole. desirable.

In addition, the cross-sectional area of the via hole is preferably smaller than that of the light emitting diode chip.

According to the present invention, it is possible to provide a high power light emitting diode printed circuit board and a heat dissipation structure of the light emitting diode using the same, which can improve the performance of the high power light emitting diode and at low cost by securing the thermal reliability of the high power light emitting diode.

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

2 is a cross-sectional view briefly showing the configuration of a heat dissipation structure of a printed circuit board for a high power light emitting diode and a light emitting diode chip according to the present invention.

As shown in FIG. 2, the heat dissipation structure 20 of the LED chip according to the present invention includes a LED package and a printed circuit board 24.

The light emitting diode package includes a light emitting diode chip 11, a light emitting diode heat sink 12, and a lead frame 13, and a built-in light emitting diode heat sink 12 includes a printed circuit board at a rear side thereof. Heat generated in the light emitting diode chip 11 is mainly emitted through the surface in contact with 24.

The printed circuit board 24 has a circuit printed on its surface, and includes a conductive layer 24a, a conductive layer 24a, and an insulating layer formed in a pattern on one or both surfaces of the insulating layer 24c and the insulating layer 24c. And an insulating coating layer 24d formed to cover at least a portion of the top surface of 24c. The conductive layer 24a is preferably made of a material having high electrical conductivity such as copper, and if necessary, a lead coating layer (not shown) is formed on a portion of the conductive layer 24a to solder the lead frame 13 of the LED package. This can be done well.

At least one via hole 24b is formed in a portion of the printed circuit board 24 in which the LED package is disposed. On the plane of the printed circuit board 24, the via hole 24b is formed at a position outside the position where the light emitting diode chip 11 disposed inside the light emitting diode package is disposed. That is, when looking at the plane of the printed circuit board 24 in a direction perpendicular thereto, the position of the light emitting diode chip 11 and the position of the via hole 24b do not overlap each other. In addition, when looking at the plane of the printed circuit board 24 in a direction perpendicular thereto, the cross-sectional area of the via hole 24b is preferably smaller than that of the light emitting diode chip 11. When the planar area of the LED chip 11 is smaller than the cross-sectional area of the via hole 24b, the LED heat sink 12 inside the LED package is formed on the printed circuit board 24 by using a separate filler. There may be occasions when it is necessary to make contact. Meanwhile, a separate heat sink 25 may be installed on the rear surface of the printed circuit board 24, and the heat sink 25 includes a plurality of plate-shaped fins.

Although not shown, the via hole 24b may be formed to penetrate the heat sink 25 in some cases. In this case, the heat radiation effect can be increased by using natural convection.

The light emitting diode heat dissipation structure 20 of the present invention shown in FIG. 2 is a printed circuit board including an insulating layer 24c and a conductive layer 24a, and a circuit is printed on the surface thereof. At least one conductive layer is exposed at a position where the light emitting diode package including the light emitting diode heat sink 12 and the lead frame 13 is to be disposed, and at least one penetrating surface opposite to one side at the position where the light emitting diode package is to be disposed. A high output light emitting diode printed circuit board 24 having via holes 24b is used. The printed circuit board according to the present invention was directly manufactured and applied to the heat dissipation structure of the light emitting diode, and the effects were examined through the following experiment.

FIG. 3 is a photograph showing a front surface of an experimental example of a high power light emitting diode printed circuit board according to the present invention, and FIG. 4 is a photograph showing a rear surface of an experimental example of a high output light emitting diode printed circuit board shown in FIG. 3. 5 shows a picture showing the front of the MPCB of the comparative example, and FIG. 6 shows a picture showing the back of the MPCB shown in FIG.

3 and 4, in the experimental example of the present invention, a plurality of through holes are formed in a portion where a light emitting diode is attached to a conventional FR-4 printed circuit board. The progress of the comparative experiment conducted with the experimental example of the present invention as shown in Figs. 3 and 4 and the comparative example using the MPCB installed on the back of the aluminum plate as shown in Figs. 4 and 5 are shown in Figs. Is shown.

The light emitting diode used in the experiment was Z power LED, P4 series 32280 of Seoul Semiconductor Co., Ltd., which is a white light emitting diode. The temperature at which the experiment was carried out was 25 ° C., and the measurement time was measured 100 times for 10 seconds at a constant current of 700 mA. CS-100 was used to evaluate the optical characteristics of the light-emitting diodes used in the experiment, SourceMeter 2430 was used to evaluate the electrical characteristics of the light-emitting diodes, and the temperature of the light-emitting diodes was controlled using a TEC controller. That is, the TEC controller controls the temperature of the light emitting diode to be maintained at the initial 25 ℃, during which the output light amount of the light emitting diode was measured to obtain a result as shown in FIG. As shown in FIG. 7, there was little change in the light emitting diode output with time between the experimental example and the comparative example. As shown in FIG. 8, there was a slight difference in the LED input voltage with time, and as shown in FIG. 9, there was a slight difference in the change in the internal resistance of the LED chip with time. It was a level that could appear due to the factor.

Through experiments, even if the present invention does not employ a structure that uses a metal PCB with a high cost, even if a conventional PCB, for example, using a low cost PCB, such as FR-4 metal PCB and It was confirmed that almost the same heat dissipation performance could be obtained.

In the following description of the present invention, the embodiments illustrated in the drawings have been described with reference to the embodiments, which are merely exemplary, and various modifications and equivalent other embodiments of the present invention may be made by those skilled in the art. I will understand the point. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a cross-sectional view briefly showing the configuration of a heat dissipation structure of a light emitting diode chip using a conventional MPCB.

Figure 2 is a cross-sectional view showing briefly the configuration of the heat radiation structure of the LED chip according to the present invention.

Figure 3 is a photograph showing the front of an experimental example of a printed circuit board for a high power light emitting diode according to the present invention.

4 is a photograph showing a rear surface of an experimental example of a printed circuit board for a high power light emitting diode shown in FIG.

Figure 5 is a photograph showing the front of the MPCB of the comparative example.

6 is a photograph showing the back of the MPCB shown in FIG.

7 to 9 are graphs showing the results of experiments comparing the operating characteristics of the light emitting diode in the comparative example using the heat dissipation structure and the MPCB of the light emitting diode chip according to the experimental example of the present invention.

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

10, 20: LED heat dissipation structure 11: LED chip

12: LED heat sink 13: lead frame

14: aluminum base 14a: conductive layer

15: lead wire 24: printed circuit board

24a: conductive layer 24b: via hole

24c: insulation layer 24d: insulation coating layer

Claims (6)

A printed circuit board comprising an insulating layer and a conductive layer, The circuit is printed on the surface At least a portion of the conductive layer is exposed at the position where the LED package including the LED chip, the LED heat sink, and the lead frame is disposed. A printed circuit board for a high power light emitting diode having one or more via holes penetrating from one side to an opposite side at a position where a light emitting diode package is to be disposed. The method of claim 1, On the plane of the printed circuit board, the via hole is formed at a position outside the position where the light emitting diode chip disposed inside the light emitting diode package is to be disposed, so that the position where the light emitting diode chip is to be disposed does not overlap with the position of the via hole. Printed circuit board for high power light emitting diodes. The method of claim 1, And a cross-sectional area of one via hole occupied on the printed circuit board is smaller than a planar area of the light emitting diode chip. A light emitting diode package including a light emitting diode chip; And A printed circuit board on which a light emitting diode package is disposed, the circuit being printed on a surface thereof; The heat dissipation structure of the LED chip having one or more via holes formed in a portion of the printed circuit board in which the LED package is disposed. The method of claim 4, wherein On the plane of the printed circuit board, the via hole is formed at a position outside the position where the light emitting diode chip disposed inside the light emitting diode package is disposed, so that the position of the light emitting diode chip and the position of the via hole do not overlap. Heat dissipation structure of LED chip. The method of claim 4, wherein The cross-sectional area of the via hole is smaller than the planar area of the light emitting diode chip, heat dissipation structure of the light emitting diode chip.

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