KR100604408B1 - Light emitting diode package - Google Patents

Abstract

The present invention relates to a light emitting diode package, and has an effect of improving light extraction efficiency.

The LED package according to the present invention for this purpose, a pair of lead frames consisting of a first lead frame and a second lead frame; A package formed by pre-molding to receive a portion of the lead frame therein while defining a molding material filling space; Respective LED chips and zener diodes mounted on the first lead frame and the second lead frame in the package; Bonding wires for electrical connection between each of the lead frame, the LED chip, and the zener diode; A molding material filled in the package to protect the LED chip, the zener diode, and the bonding wire; And a protrusion formed in a space between the first lead frame and the second lead frame.

Light Emitting Diodes, Package, Zener Diodes

Description

Light emitting diode package

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

Figure 2 is a cross-sectional view for explaining the problem of the LED package according to the prior art.

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

4 is a cross-sectional view showing an optical path in the LED package according to the embodiment of the present invention.

5 is a graph showing a radiation pattern of the LED chip.

6 is a diagram illustrating luminance characteristics depending on whether zener diode is applied or not.

<Description of Symbols for Main Parts of Drawings>

200: light emitting diode package 210: lead frame

210a: first lead frame 210b: second lead frame

220: package 230: LED chip

240: Zener diode 250: bonding wire

250a: first bonding wire 250b: second bonding wire

250c: third bonding wire 260: molding material

270: protrusion

The present invention relates to a light emitting diode package, and more particularly, to a light emitting diode package capable of preventing light emitted from an LED chip from being absorbed by a zener diode to improve light extraction efficiency.

In general, a light emitting diode (LED) is an electronic component that generates a minority carrier (electron or hole) injected by using a p-n junction structure of a semiconductor and emits light by recombination thereof. In other words, when a forward voltage is applied to a semiconductor of a specific element, electrons and holes are recombined with each other as the electrons and holes move through the junction portions of the anode and the cathode, which is smaller than when the electrons and holes are separated. Emits.

Such a light emitting diode can be irradiated with high efficiency light at low voltage, and thus is used in home appliances, remote controls, electronic signs, indicators, and various automation devices. In particular, according to the trend toward miniaturization and slimming of information and communication devices, various components such as resistors, capacitors, and noise filters are becoming more miniaturized, and surface-mounted light emitting diodes are directly mounted on a printed circuit board (PCB). It is made by a surface mount device (SMD) method.

SMD type light emitting diode package is mainly used as a backlight unit for liquid crystal display used in mobile phones. In general, light emitting diodes are known to be vulnerable to electrostatic discharge (ESD) characteristics.

Therefore, in order to compensate for the weakness of the light emitting diode, a means for flowing current in a reverse direction is provided, and in such a means, it is preferable to efficiently respond to static electricity by connecting a zener diode in parallel with the light emitting chip. Doing. That is, a light emitting diode and a zener diode are mounted on the anode and the cathode, and the light emitting diode and the zener diode are connected to each other with a gold (Au) wire or the like to have a parallel structure.

1 is a cross-sectional view showing a light emitting diode package according to the related art to which a zener diode is applied.

As shown in FIG. 1, the LED package 100 according to the related art includes a pair of lead frames 110 including a first lead frame 110a and a second lead frame 110b, and the lead frame. A package 120 formed by pre-molding to define a molding material filling space while accommodating a portion of the 110 therein, and a first lead frame 110a and a second lead frame 110b inside the package 120. Each of the LED chip 130 and the zener diode 140 mounted on the LED chip, and the bonding wire 150 for the electrical connection between the lead frame 110, the LED chip 130, and the zener diode 140, respectively. And a molding material 160 filled in the package 120 to protect the LED chip 130, the zener diode 140, and the bonding wire 150.

The package 120 formed by the pre-molding process is generally made of plastic or the like, and PPA (polyphthalamide) resin or the like may be used as the plastic. In addition, the molding material 160 may be made of a light-transmissive resin containing a transparent material or a phosphor according to the color of the LED chip 130 to be implemented.

In addition, the bonding wire 150 may include a first bonding wire 150a electrically connecting the LED chip 130 and the first lead frame 110a, the LED chip 130, and the second lead. A second bonding wire 150b for electrically connecting the frame 110b and a third bonding wire 150c for electrically connecting the zener diode 140 and the first lead frame 110a are included.

The bonding wire 150 is generally made of gold (Au), and allows the LED chip 130 and the zener diode 140 to be connected in parallel. Here, the LED chip of the conventional method is applied to the LED chip 130, preferably a GaN-based LED chip is used. The zener diode 140 is generally made of a material such as silicon (Si).

However, the conventional LED package as described above has the following problems. 2 is a cross-sectional view illustrating a problem of a light emitting diode package according to the related art. As shown in FIG. 2, the zener diode connected in parallel with the LED chip 130 to improve resistance to ESD ( In relation to the case in which the 140 is made of silicon, a portion of the light emitted from the LED chip 130 is absorbed by the zener diode 140 (see reference numeral 'A'), thereby lowering the light extraction efficiency. .

Accordingly, in order to minimize absorption of light by the zener diode 140, the height and size of the zener diode 140 are minimized and used within a range in which required ESD resistance can be secured. However, there is a limit in minimizing the height and size of the zener diode 140, which leads to difficulty in overcoming the problem.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide a light emitting diode package that can improve the light extraction efficiency by preventing the light emitted from the LED chip is absorbed by the Zener diode. .

The light emitting diode package according to the present invention for achieving the above object,

A pair of lead frames consisting of a first lead frame and a second lead frame;

A package formed by pre-molding to receive a portion of the lead frame therein while defining a molding material filling space;

Respective LED chips and zener diodes mounted on the first lead frame and the second lead frame in the package;

Bonding wires for electrical connection between each of the lead frame, the LED chip, and the zener diode;

A molding material filled in the package to protect the LED chip, the zener diode, and the bonding wire; And

And a protrusion formed in a space between the first lead frame and the second lead frame.

Here, the protrusion is characterized in that it has any one cross-sectional shape selected from the group consisting of triangular, square, hemispherical and combinations thereof.

The protrusion may be formed during the pre-molding process for forming the package.

In addition, the protrusion is characterized in that formed by the bonding process.

In addition, the protrusion is characterized in that made of plastic.

In addition, PPA resin is used as the plastic.

In addition, the height of the protrusion is characterized in that 30㎛ or more.

The bonding wire may include a first bonding wire for electrical connection between the LED chip and the first lead frame, a second bonding wire for electrical connection between the LED chip and the second lead frame, and the zener diode. And a third bonding wire for electrical connection of the first lead frame.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

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

As shown in FIG. 3, the LED package 200 according to the embodiment of the present invention includes a pair of lead frames 210 including a first lead frame 210a and a second lead frame 210b, A package 220 formed by pre-molding to define a molding material filling space while accommodating a portion of the lead frame 210 therein, the first lead frame 210a and the first inside of the package 220. Each LED chip 230 and the zener diode 240 mounted on the 2 lead frame 210b, and the electrical connection of each of the lead frame 210 and the LED chip 230 and the zener diode 240, And a molding material 260 filled in the bonding wire 250 and the package 220 to protect the LED chip 230, the zener diode 240, and the bonding wire 250.

Here, the LED chip of the conventional method is applied to the LED chip 230 as described above, preferably a GaN-based LED chip is used. In addition, the zener diode 240 has physical properties having a predetermined static withstand voltage with respect to the reverse current. Therefore, when a reverse current is applied to the LED chip 230 by static electricity or the like, current may be bypassed by the zener diode 240 to prevent damage due to static electricity. The zener diode 240 is generally made of a material such as silicon (Si). In addition, the molding material 260 is made of a light-transmissive resin containing a transparent material or a phosphor according to the color of the LED chip 230 to be implemented.

The package 220 formed by the pre-molding process is generally made of plastic or the like, and PPA (polyphthalamide) resin or the like may be used as the plastic. At this time, in the embodiment of the present invention, in the space between the first lead frame 210a on which the LED chip 230 is mounted and the second lead frame 210b on which the zener diode 240 is mounted, the LED A protrusion 270 is additionally formed to allow light emitted from the side of the chip 230 to be extracted to the outside without being absorbed by the zener diode 240 made of silicon.

The protrusion 270 is formed together with the package 220 during the pre-molding process for forming the package 220. Accordingly, the protrusion 270 is made of the same material as the package 220, that is, plastic such as PPA resin. In addition, the protrusion 270 may be formed through a separate bonding process instead of being formed during the pre-molding process for forming the package 220 as described above. In this case, the protrusion 270 may also be formed. ) Is preferably formed using a plastic such as PPA resin.

In addition, the protrusion 270 may have a triangular cross-sectional shape as shown in the drawing. At this time, the shape of the protrusion 270 is not limited to the shape as described above, and may be variously modified, including, for example, square, hemispherical, and combinations thereof within the technical scope of the present invention.

On the other hand, the bonding wire 250, as described above, the first bonding wire 250a for the electrical connection between the LED chip 230 and the first lead frame 210a, the LED chip 230 And a second bonding wire 250b for electrical connection between the second lead frame 210b and a third bonding wire 250c for electrical connection between the zener diode 240 and the first lead frame 210a. It includes. The bonding wire 250 is generally made of gold (Au) and allows the LED chip 230 and the zener diode 240 to be connected in parallel.

4 is a cross-sectional view illustrating an optical path in the LED package according to the embodiment of the present invention. As shown in FIG. 4, in the present invention, light emitted from the side surface of the LED chip 230 is formed in a space between the first lead frame 210a and the second lead frame 210b. Since the protrusion 270 having a predetermined shape is additionally formed to be extracted to the outside without being absorbed by the 240, the light extraction efficiency may be improved by securing the light that is absorbed and lost by the zener diode 240.

For reference, FIG. 5 is a graph illustrating a radiation pattern of an LED chip, and FIG. 6 is a diagram illustrating luminance characteristics depending on whether a zener diode is applied.

As a result of observing the light emission pattern of the LED chip 230, the light emitted from the LED chip 230 is actually emitted through the side surface of the LED chip 230, as shown in FIG. 5. . Therefore, by applying the protrusion 270 as described above to the light emitting diode package 200, a considerable level of luminance improvement can be expected.

In particular, according to the existing experimental results shown in FIG. 6, when the zener diode 240 is applied to the light emitting diode package 200, light emitted from the LED chip 230 is absorbed by the zener diode 240. As compared with the case where the zener diode 240 is not applied, the luminance characteristic is reduced by about 12%. However, in the present invention, by applying the protrusion 270, an improvement in light extraction efficiency of at least 5% or more can be expected as compared with the conventional case of applying the zener diode 240. In this case, when the height of the protrusion 270 is substantially smaller than 30 μm in consideration of the size of a general LED chip 230, it is difficult to expect a light extraction efficiency improvement effect of a predetermined level or more, and thus the protrusion 270 is 30 It is preferred to have a height of at least mu m.

Although the preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

As described above, according to the light emitting diode package according to the present invention, the LED is additionally formed in a space between the first lead frame on which the LED chip is mounted and the second lead frame on which the Zener diode is mounted, thereby providing the LED. Light emitted from the side of the chip can be extracted to the outside without being absorbed by the zener diode made of silicon. Therefore, the present invention can improve the light extraction efficiency of the light emitting diode device by ensuring the light is absorbed and lost by the zener diode.

Claims (8)

A pair of lead frames consisting of a first lead frame and a second lead frame; A package formed by pre-molding to receive a portion of the lead frame therein while defining a molding material filling space; Respective LED chips and zener diodes mounted on the first lead frame and the second lead frame in the package; Bonding wires for electrical connection between each of the lead frame, the LED chip, and the zener diode; A molding material filled in the package to protect the LED chip, the zener diode, and the bonding wire; And The LED package including a protrusion formed in the space between the first lead frame and the second lead frame. The method of claim 1, The protrusion has a cross-sectional shape of any one selected from the group consisting of triangular, rectangular, hemispherical and combinations thereof. The method of claim 1, The protrusion is a light emitting diode package, characterized in that formed during the pre-molding process for forming the package. The method of claim 1, The protrusion is a light emitting diode package, characterized in that formed by a bonding process. The method of claim 1, The projection LED package, characterized in that made of plastic. The method of claim 5, wherein A light emitting diode package using PPA resin as said plastic. The method of claim 1, The height of the protrusion is a light emitting diode package, characterized in that more than 30 ㎛. The method of claim 1, The bonding wire may include a first bonding wire for electrical connection between the LED chip and the first lead frame, a second bonding wire for electrical connection between the LED chip and the second lead frame, and the zener diode and the first lead wire. A light emitting diode package comprising a third bonding wire for electrical connection of one lead frame.

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