KR20070076075A - Printed circuit board for setting light-emitting diode thereon - Google Patents

Abstract

A printed circuit board for setting a light-emitting diode thereon is provided to reduce a unit cost by using an insulation substrate and to obtain a high heat dissipation performance by a heat dissipation conductive pad. A printed circuit board for mounting a light-emitting diode includes a first heat dissipation conductive pad(3a), a second heat dissipation conductive pad(3b), a plurality of light emitting diodes(11), a first electrode(13a), and a second electrode(13b). The first and second heat radiating conductive pads(3a,3b) have an enough area to discharge the heat generated from the light emitting diodes(11). The plurality of light emitting diodes(11) are mounted on the insulation substrate(1). The light emitting diode(11) includes the first and second electrodes(13a,13b). The first and second heat dissipation conductive pads(3a,3b) are located at a lower part of each light emitting diode(11).

Description

Printed circuit board for setting light-emitting diode thereon}

1 shows a top view of a printed circuit board according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1.

3 is a view illustrating a light emitting diode mounted on the printed circuit board of FIG. 2.

4 is a view illustrating a light emitting diode separated from a printed circuit board of FIG. 2.

The present invention relates to a printed circuit board, and more particularly to a printed circuit board for mounting a light emitting diode.

In general, light emitting diodes (LEDs) are widely used as light sources due to various advantages such as low power consumption and high brightness. In particular, recently, light emitting diodes are used as backlight devices for lighting devices and large liquid crystal displays (LCDs). do.

On the other hand, a printed circuit board on which a light emitting diode is mounted also requires heat dissipation performance for dissipating heat generated from the light emitting diode. High heat dissipation performance is a more important condition in the field where high power light emitting diodes such as backlighting for general lighting devices and large LCDs are required.

As a structure to maximize the heat dissipation performance according to the prior art there is a structure to replace the entire surface of one side of the printed board with a metal plate. However, when the metal plate is used on the front surface, the cost of the printed circuit board increases. In addition, light emitting diodes are mounted on a printed circuit board by soldering, which mainly uses heat. However, if a bad light emitting diode is present among the mounted light emitting diodes, the bad light emitting diode must be separated from the printed circuit board. Heat is applied to the metal plate of the printed circuit board to melt the solder (solder) in order to separate the defective LED from the printed circuit board. However, since one side of the printed circuit board is all made of a metal plate, heat is easily transferred to the entire metal plate, thereby melting not only the solder under the defective LED but also the solder under the normal LED. Therefore, it is not easy to remove only one specific bad light emitting diode.

Accordingly, an aspect of the present invention is to provide a printed circuit board having excellent heat dissipation characteristics and easy to separate or mount a light emitting diode.

The printed circuit board according to the present invention for achieving the above technical problem is characterized in that provided with heat radiation conductive pads corresponding to the individual light emitting diodes on the insulating substrate. By using an insulated substrate, the unit cost of the product can be lowered and excellent heat dissipation performance can be exhibited by the heat dissipation conductive pad. In addition, it is easy to separate only the desired light emitting diode from the printed circuit board by applying heat to the heat radiation conductive pad corresponding to the desired light emitting diode to melt the solder.

More specifically, the printed circuit board is an insulating substrate; A plurality of light emitting diodes mounted on the insulating substrate and having a first electrode and a second electrode; A first heat dissipation conductive pad electrically connected to the first electrode of each light emitting diode and positioned between the first electrode and the insulating substrate; A second heat radiation conductive pad electrically connected to the second electrode of each light emitting diode and positioned between the second electrode and the insulating substrate and spaced apart from the first heat radiation conductive pad; And covering upper and side surfaces of the first and second heat dissipating conductive pads and an upper surface of the insulating substrate adjacent to the first and second heat dissipating conductive pads, and exposing a portion of the first heat dissipating conductive pads. And an insulating layer including a first heating hole spaced apart from the light emitting diode and a second heating hole spaced apart from the light emitting diode to expose a portion of the second heat dissipation conductive pad.

The insulating layer may further include a first connector spaced apart from the first heating port and exposing the first heat radiation conductive pad, and a second connector spaced apart from the second heating port and exposing the second heat radiation conductive pad. The first electrode and the second electrode contact the first and second heat dissipation conductive pads through the first connector and the second connector, respectively.

Solder may be interposed between the first electrode and the first heat dissipation conductive pad and between the second electrode and the second conductive pad.

Heat is applied to the first and second heat dissipation conductive pads exposed by the first and second heat dissipation holes, respectively, so that the solder melts to separate the light emitting diodes from the first and second heat dissipation conductive pads. have. Thereby, the predetermined light emitting diode can be easily separated from the insulating substrate without affecting neighboring light emitting diodes.

The first and second heat dissipation conductive pads may be made of copper. The sum of the area of the first heat dissipation conductive pad and the area of the second heat dissipation conductive pad is preferably larger than the area of the light emitting diode.

Hereinafter, 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 described herein and may be applied and modified in various forms. Rather, the following examples are provided to clarify the technical spirit disclosed by the present invention and to further convey the technical spirit of the present invention to those skilled in the art having an average knowledge in the field to which the present invention belongs. Therefore, the scope of the present invention should not be construed as limited by the embodiments described below. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. Portions denoted by like reference numerals denote like elements throughout the specification.

1 shows a top view of a printed circuit board according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II ′ of FIG. 1.

1 and 2, the printed circuit board 100 according to the present embodiment includes an insulating substrate 1. The insulating substrate 1 is made of an insulating material such as epoxy. The first heat dissipation conductive pad 3a and the second heat dissipation conductive pad 3b are positioned on the insulating substrate 1. The first and second heat dissipation conductive pads 3a and 3b are spaced apart from each other, for example, made of copper. One first heat dissipation conductive pad 3a and one second heat dissipation conductive pad 3b neighboring each other overlap one light emitting diode 11 in a pair. The sum of the areas of the first and second heat dissipation conductive pads 3a and 3b is larger than that of the light emitting diodes 11 and has a sufficient area to dissipate heat generated from the light emitting diodes 11. The light emitting diodes 11 are mounted on the insulating substrate 1. The light emitting diode 11 has a first electrode 13a and a second electrode 13b. Underneath each light emitting diode 11 are corresponding first and second heat dissipation conductive pads 3a and 3b. The first heat dissipation conductive pad 3a may be connected to the second heat dissipation conductive pad 3b by a conductive line 3c. The conductive lines 3c may be provided in plural to connect the first heat dissipation conductive pads 3a and the second heat dissipation conductive pads 3b to other corresponding circuit elements (not shown). The conductive line 3c may be formed of the same material on the insulating substrate 1 together with the first and second heat dissipation conductive pads 3a and 3b. The conductive line 3c is sufficient to electrically connect the first and second heat dissipation conductive pads 3a to the circuit elements (not shown), respectively, but to adjacent heat dissipation conductive pads 3a and 3b. It has a certain thickness and width which is very insufficient to transfer heat.

1 and 2, the insulating substrate 1 on which the first and second heat dissipating conductive pads 3a and 3b and the conductive line 3c are formed covers the insulating film 5. The insulating layer 5 overlaps the first electrode 13a and exposes the first heat dissipation conductive pad 3a, and the second heat dissipation overlaps with the second electrode 13b. It has a 2nd connector 9b which exposes the conductive pad 3b. In addition, the insulating layer 5 is spaced apart from the first connector 9a and is spaced apart from the first heating port 7a exposing the first heat dissipation conductive pad 3a and the second connector 9b. It has a 2nd heating opening 7b which exposes the 2nd heat radiation conductive pad 3b.

Meanwhile, a method of mounting the light emitting diode 11 to the printed circuit board 100 of FIGS. 1 and 2 will be described with reference to FIG. 3.

Referring to FIG. 3, the first and second heat-dissipating conductive pads 3a and 3b exposed to the first and second connectors 9a and 9b or the first and second portions of the light emitting diodes 11 are provided. Solders 15a and 15b are formed on the second electrodes 13a and 13b. The light emitting diode 11 is positioned, pressurized, and cooled so that the first and second electrodes 13a and 13b overlap the first and second connectors 9a and 9b.

Meanwhile, when a bad light emitting diode is generated among the light emitting diodes 11 mounted on the printed circuit board 100 as shown in FIG. 3, a method of separating it from the printed circuit board 100 is described with reference to FIG. 4. Let's explain.

Referring to Fig. 4, a heating mechanism 17 is connected to the first and second heat dissipation conductive pads 3a and 3b exposed by the first and second heating ports 7a and 7b. As a result, heat is transferred from the first and second heat dissipation conductive pads 3a and 3b in the direction of the arrow to melt the solders 9a and 9b. Therefore, the light emitting diode 11 may be separated from the printed circuit board 1. At this time, the periphery of the first and second heat dissipation conductive pads 3a and 3b are all surrounded by the insulating substrate 1 and the insulating film 5, and thus the first and second heat dissipation conductive pads 3a and 3b. The heat is not transferred to the solders 9a and 9b of the neighboring light emitting diodes 11. Accordingly, only the desired light emitting diode 11 may be separated from the printed circuit board 100 by applying heat only to the first and second heat dissipating conductive pads 3a and 3b disposed under the desired light emitting diode 11.

The printed circuit board 100 may be applied to a backlight unit for an LCD (Liquid Crystal Display).

Therefore, the printed circuit board according to the present invention is characterized in that the heat radiation conductive pads corresponding to the individual light emitting diodes on the insulating substrate. By using an insulated substrate, the unit cost of the product can be lowered and excellent heat dissipation performance can be exhibited by the heat dissipation conductive pad. In addition, it is easy to separate only the desired light emitting diode from the printed circuit board by applying heat to the heat radiation conductive pad corresponding to the desired light emitting diode to melt the solder.

Claims (6)

Insulating substrate; A plurality of light emitting diodes mounted on the insulating substrate and having a first electrode and a second electrode; A first heat dissipation conductive pad electrically connected to the first electrode of the light emitting diode and positioned between the first electrode and the insulating substrate; A second heat dissipation conductive pad electrically connected to the second electrode of the light emitting diode and positioned between the second electrode and the insulating substrate and spaced apart from the first heat dissipation conductive pad; And Covering top and side surfaces of the first and second heat dissipation conductive pads and the top surface of the insulating substrate adjacent to the first and second heat dissipation conductive pads, and exposing a portion of the first heat dissipation conductive pads to emit light. And an insulating film having a first heating hole spaced apart from the diode and a second heating hole spaced apart from the light emitting diode while exposing a portion of the second heat dissipation conductive pad. The method of claim 1, The insulating layer further includes a first connector spaced apart from the first heating port and exposing the first heat dissipation conductive pad, and a second connector spaced apart from the second heating port and exposing the second heat dissipation conductive pad, And the first electrode and the second electrode are electrically connected to the first and second heat dissipation conductive pads through the first connector and the second connector, respectively. The method of claim 2, Solder is interposed between the first electrode and the first heat dissipation conductive pad and between the second electrode and the second heat dissipation conductive pad so that the first and second electrodes are respectively exposed to the first and second heat dissipation conductive. A printed circuit board, electrically connected to the pad. The method of claim 1, And the first and second heat dissipation conductive pads are made of copper. The method of claim 1, The sum of the area of the first heat dissipation conductive pad and the area of the second heat dissipation conductive pad is larger than the area of the light emitting diode. Insulating substrate; A plurality of light emitting diodes mounted on the insulating substrate and having a first electrode and a second electrode; A first heat radiation conductive pad electrically connected to the first electrode of the light emitting diode via a solder and positioned between the first electrode and the insulating substrate; A second heat radiation conductive pad electrically connected to the second electrode of the light emitting diode via a solder and positioned between the second electrode and the insulating substrate and spaced apart from the first heat radiation conductive pad; And covering upper and side surfaces of the first and second heat dissipating conductive pads and an upper surface of the insulating substrate adjacent to the first and second heat dissipating conductive pads, and exposing a portion of the first heat dissipating conductive pads. A method of separating a light emitting diode from a printed circuit board comprising an insulating film having a first heating hole spaced apart from the light emitting diode and a second heating hole spaced apart from the light emitting diode while exposing a portion of the second heat dissipation conductive pad. to, Applying heat to the first and second heat dissipation conductive pads exposed by the first and second heating holes, respectively, to melt the solder to separate the light emitting diodes from the first and second heat dissipation conductive pads. .

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