KR20090104580A - Light emitting diode package using printed circuit board - Google Patents

Abstract

PURPOSE: A light emitting diode package using a printed circuit board is provided to improve workability and heat radiation by making the light emitting diode package small. CONSTITUTION: A light emitting diode package using a printed circuit board is composed of first metal layer metal layers(17,16a,16b) and the second metal layer(12). A substrate includes at least a metal layer and the insulating layer(14) laminated on the metal layer(13). The substrate has a recessed groove in which the LED chip is received. The first metal layers reflect a light while being spread over the whole surface of the received groove, and the second metal layers are spread at a lower part of the metal layer.

Description

LIGHT EMITTING DIODE PACKAGE USING PRINTED CIRCUIT BOARD

The present invention relates to a light emitting diode package using a printed circuit board, and more particularly, to a light emitting diode package using a printed circuit board having a structure capable of providing high reliability by providing excellent heat dissipation characteristics.

In general, a light emitting diode (hereinafter, referred to as "LED") is an element in which electrons and holes meet and emit light at a PN junction by application of current, and are in the form of a package in which an LED chip is mounted. Is produced. This is referred to as an LED package, which is typically mounted on a printed circuit board (PCB) can be applied to the current to emit light.

In recent years, such LEDs are being greatly highlighted for lighting, and the use of light is gradually increasing due to their excellent efficiency and characteristics compared to other lighting devices, and the manufacturing cost is also lowered, thereby increasing competitiveness.

However, as LEDs become smaller and smaller, they face several important problems. In particular, heat dissipation is a big problem. The heat generated from the LED chip in the LED package has a direct impact on the luminous performance and lifetime of the LED package. The reason is that if the heat generated in the LED chip persists, dislocations and mismatches occur in the crystal structure of the LED chip.

Moreover, in recent years, high power LED packages have been developed. These high power LED packages operate in a high voltage environment, and the high voltage generates more heat from the LED chip, so a plan for effectively dissipating the generated heat is required. do.

In the case of many conventional LED packages, polyphthalamide (hereinafter referred to as "PPA") resin or ceramic is widely used as a material for the housing constituting the package body. This is because the reflectance is high enough that the housing can act as a reflector. Alternatively, the reflective surface may be coated or plated to increase the reflectance.

However, in the case of PPA resin, since the heat dissipation characteristics are not good, it is not only discolored when used for a long time, but also degrades the overall performance of the LED package. In addition, in the case of ceramics, although the heat dissipation characteristics are superior to PPA resins, there are problems such as being restricted in use according to processing characteristics according to the miniaturization of the package.

Since the heat dissipation problem in the LED package is directly related to the reliability of the LED package, a new structure of LED will be required to solve the heat dissipation problem.

Accordingly, an object of the present invention is to improve the above-described conventional problems, and in particular, to improve overall characteristics of an LED package by improving processability or heat dissipation characteristics corresponding to miniaturization of a package.

Another object of the present invention is to provide an LED package using a printed circuit board which can prevent oxidation of the package main material and improve the reliability of the package.

Still another object of the present invention is to provide an LED package using a printed circuit board that directly mounts an LED chip on a metal layer of a printed circuit board to improve heat dissipation and to increase light mixing distance when manufacturing a backlight unit.

A light emitting diode package according to an aspect of the present invention for achieving the above object includes at least a metal layer and an insulating layer stacked thereon, wherein an insulating layer of a predetermined region is formed to form a reflecting cup to accommodate the LED chip. A substrate having a space removed and recessed; A first metal film applied to the entire surface of the recessed space of the substrate to reflect light; And a second metal film applied to the lower portion of the metal layer.

Preferably, the first metal film and the second metal film may be silver or gold.

Preferably, the metal layer may be made of copper, and the insulating layer may be Flame Retardant type 4 (FR4).

A light emitting diode package according to another aspect of the present invention for achieving the above object comprises a metal layer for dissipating heat due to the LED chip; An insulating layer stacked on top of the metal layer, the predetermined layer being removed to provide a predetermined recessed space for forming a reflecting cup to accommodate the LED chip; Two or more package electrodes, each of which is insulated by the insulating layer and to which the LED chip is electrically connected; And a first metal film applied to the entire surface of the recessed space of the insulating layer to reflect light.

Preferably, the first metal film may be further coated on the package electrode.

Preferably, a second metal film may be further applied below the first metal film.

Preferably, a second metal film for protecting the metal layer may be further applied to the lower portion of the metal layer.

The present invention has the effect of improving the overall characteristics of the LED package by providing an LED package using an improved printed circuit board, by improving the workability or heat dissipation characteristics corresponding to the miniaturization of the package. In particular, the present invention can reduce the overall height of the LED package has the effect of greatly improving the light mixing distance when manufacturing the backlight unit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following descriptions are given by way of example only and without limitation, except for the purpose of helping those skilled in the art to understand the present invention to limit the scope of the invention. It should not be used.

1 is a schematic plan view of an LED package using a printed circuit board according to an embodiment of the present invention, FIG. 2 is a bottom view of the LED package corresponding to FIG. 1, and FIG. 3 is along A1 and A2 in FIG. 1. It is a cut section.

First, referring to FIG. 1, the insulating layer 14 constituting a part of the substrate, the first metal layers 17, 16a, 16b, 16c, and 16d, the bonding wire W, the LED chips 11a and 11b, The optical lens 19 and the reflecting cup 18a are shown. 2, the insulating layer 14 and the second metal films 12, 26a, 26b, 26c, and 26d are further seen. The first metal films 17, 16a, 16b, 16c, and 16d are metal films applied to the upper exposed surface of the LED package, and the second metal films 12, 26a, 26b, 26c and 26d are exposed to the lower side of the LED package. It is a metal film applied to the surface. Reference numerals 26a, 26b, 26c, and 26d denote metal films applied to the lower portions of the surfaces of the electrodes 16a, 16b, 16c, and 16d, respectively.

The metal film 17 is applied to the entire surface of the reflective cup 18a. Although will be shown in detail in FIG. 3 later, the reflecting cup is composed of side surfaces 18b and 18c and bottom surface 18a, and the surface is entirely coated with a metal film 17. Application of the metal film 17 to the reflective cups 18a, 18b, and 18c may be by coating or plating, but is not limited to these methods.

The metal layer 17 may be a metal such as silver (Ag) or gold (Au), but is not limited thereto. Preferably, the metal film 17 may be silver (Ag).

The metal film 12 is applied to the lower portion of the metal layer to be described below with reference to FIG. 3 to protect the metal layer. The metal layer is a part serving as a heat sink. The metal film 12 may also be a metal such as silver or gold, but is not limited thereto.

Referring to FIG. 3, the LED chips 11a and 11b, the reflective cups 18a, 18b and 18c, the first metal films 17, 16a and 16b, the electrodes 15a and 15b, the optical lens 19, and the metal layer 13 and insulating layer 14 are shown.

Referring to FIG. 3 together with FIGS. 1 and 2 above, an LED package according to an embodiment of the present invention includes a substrate, which includes a metal layer 13 and an insulating layer 14, and the substrate The insulating layer in a predetermined area is removed to form the reflection cups 18a, 18b, and 18c in which the LED chips 11a and 11b are to be accommodated. Removal of the insulating layer to form a recessed space may be by an etching method. Alternatively, the recessed space may be realized by adhering the cross-sectional PCB of the insulating layer on top of the metal layer, or may be implemented by various methods such as bonding the insulating layer on the top of the metal layer and drilling. have.

The LED chips 11a and 11b are devices in which electrons and holes meet and emit light at a P-N junction by applying an electric current, and are electrically connected to the electrodes 15a and 15b through a wire W.

The electrodes 15a and 15b are made of a metal with good conductivity, and the surface of the electrode can be coated with the metal films 16a and 16b. As described above, the metal films 16a and 16b may be applied to the surfaces of the electrodes 15a and 15b to protect the main materials of the electrodes 15a and 15b. The metal films 16a and 16b may be gold or silver, but are not limited thereto.

The reflection cups 18a, 18b, and 18c serve as reflectors, that is, parts for reflecting light emitted from the LED chips 11a and 11b to further increase reflection efficiency. The reflective cups 18a, 18b, and 18c may be molded in such a way that the upper portion of the metal layer 13 is exposed by removing the insulating layer 14 in the substrate to form a predetermined recessed space. The metal film 17 is applied to the side surface, that is, the side surface of the insulating layer 14 and the entire upper portion of the metal layer 13. As described above, since the metal film 17 is applied to a portion exposed to the upper portion of the package in the same manner as the metal films 16a and 16b applied to the upper portions of the electrodes 15a and 15b, all of them are referred to as first metal films.

The metal layer 13 may function as a heat sink, and preferably may be made of copper, but is not limited thereto.

The metal film 12 may be applied to the lower portion of the metal layer 13 to prevent oxidation or damage of the metal layer 13. The material of the metal film 12 may be gold or silver with good conductivity, but is not limited thereto.

The insulating layer 14 is stacked on top of the metal layer 13 and constitutes a main portion of the substrate together with the metal layer 13, and the insulating layer 14 is, for example, FR4 (Flame Retardant type 4) or the like. It may be a flame retardant material, but is not limited thereto.

Although the LED chips 11a and 11b packaged in FIGS. 1 to 3 are illustrated as two, the number of such LED chips is only an example, and may be one or three or more.

As described above, the LED package using the printed circuit board according to the present invention has a second material at the bottom of the metal layer 13 and the bottom of the electrodes 15a, 15b, 15c, and 15d for functioning as a main material of the package, that is, a heat sink. By applying the metal film (the metal film 12 and the metal films 26a, 26b, 26c, and 26d, respectively), oxidation and damage of the main material can be prevented, thereby improving the reliability of the LED package. .

In addition, by applying the first metal film (metal film 17) to the inside of the reflecting cup to form a reflector in the package, the reliability of the package can be improved by preventing oxidation and damage of the main material.

In addition, an insulating layer 14 such as FR4 constituting the package is removed to form a recessed space, and a metal film directly applied to the metal layer 13 functioning as a heat sink (strictly, the bottom surface of the reflecting cup). (18a)) Since it is mounted, the heat dissipation characteristics are very excellent, and when the backlight unit is manufactured by greatly reducing the overall height of the package, the light mixing distance can be greatly improved.

Furthermore, since the application of the optical lens 19 may be considered from the design stage, the mounting of the lens may be easy, and as shown in FIG. 3, the electrodes 26a, 26b, 26c, and 26d may be formed on the bottom to form a PCB. Despite the package applied, the Surface Mount Technology (SMT) operation is possible.

LED package using a printed circuit board according to the present invention is not limited to the above embodiments, it can be variously designed and applied within the scope without departing from the basic principles of the present invention is common knowledge in the art It will be obvious to those who have.

1 is a schematic plan view of an LED package using a printed circuit board according to an embodiment of the present invention;

2 is a bottom view of the LED package corresponding to FIG. 1, and

3 is a cross-sectional view taken along the lines A1 and A2 of FIG. 1.

Claims (8)

A substrate having at least a metal layer and an insulating layer stacked thereon, the substrate having a recessed space in which the LED chip is to be accommodated; A first metal film applied to the entire surface of the recessed space of the substrate to reflect light; And The light emitting diode package comprising a second metal film applied to the lower portion of the metal layer. The method according to claim 1, The first metal film and the second metal film is a light emitting diode package, characterized in that the silver or gold. The method according to claim 1, The metal layer is a light emitting diode package, characterized in that consisting of copper. The method according to claim 1, The insulating layer is a light emitting diode package, characterized in that FR4 (Flame Retardant type 4). A metal layer for dissipating heat due to the LED chip; An insulating layer stacked on top of the metal layer, the predetermined region being removed to provide a predetermined recessed space for accommodating the LED chip; Two or more package electrodes, each of which is insulated by the insulating layer and the LED chip is wire bonded; And a first metal film applied to an entire surface of the recessed space of the insulating layer to reflect light. The method according to claim 5, The first metal film is a light emitting diode package, characterized in that further applied on top of the package electrode. The method according to claim 5, The LED package of claim 2, wherein the second metal film is further applied to the lower portion of the package electrode. The method according to claim 5, The lower portion of the metal layer is a light emitting diode package, characterized in that further coating a second metal film for protecting the metal layer.

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