KR101374898B1 - Led package with its interfacial delamination reduced - Google Patents

Abstract

 Disclosed is an LED package which exists in an LED package, in particular, in which the separation phenomenon at the interface between the leadframe and the encapsulant is reduced. The disclosed LED package includes a base on which an LED chip is mounted, a reflector formed by molding a resin on the base to define a cavity around the LED chip, an encapsulant made of a light-transmissive resin material formed in the cavity, and And a stepped structure formed to widen the bonding area with the encapsulant on the inner side of the reflector.

Reflector, stepped structure, LED. Package, Encapsulant, Interface, Separation

Description

LED package with reduced interface separation {LED PACKAGE WITH ITS INTERFACIAL DELAMINATION REDUCED}

The present invention relates to an LED package, and more particularly, to an LED package that reduces the separation phenomenon at the interface, in particular, the interface between the lead frame and the encapsulant present in the LED package.

A light emitting diode (LED) is a device in which electrons and holes meet and emit light in a p-n semiconductor junction structure of a semiconductor by application of a current. Such LEDs are generally manufactured in the structure of a package on which an LED chip is mounted, and are commonly referred to as an 'LED package'. A typical LED package is generally mounted on a printed circuit board (PCB) and configured to emit light by receiving current from an electrode formed on the printed circuit board.

A typical LED package includes at least two lead frames for applying current to an LED chip, a housing that supports the lead frame and functions as a reflector, and is formed in a cavity formed in the housing to protect the LED chip from the outside. It consists of a structure containing a transparent sealing material. The LED package having the above structure has a problem in that the production yield is low due to a complicated process of injection molding resin on a lead frame.

In contrast, conventionally, instead of omitting a housing formed by injection molding, for example, a resin is directly formed on a lead frame to form a reflector, and the sealing material is doted into a cavity formed by the reflector. The LED package that is formed and manufactured by the method has been developed. Such a conventional LED package has the advantage that the manufacturing process is simple and its production yield is high.

However, the conventional LED package, there is a problem that the interface separation phenomenon occurs between the lead frame and the encapsulant having a material material significantly different. Even such an interface separation phenomenon causes the bonding wire connected between the LED chip and the lead frame to be separated from the lead frame together with the encapsulant, resulting in a failure of the LED package not to light up.

Therefore, the technical problem of the present invention is produced by forming a reflector and an encapsulant on a lead frame or any base corresponding thereto, and the encapsulant is interfacially separated from the reflector or a corresponding base by increasing the bonding force between the reflector and the encapsulant. It is to provide an LED package in which the phenomenon is suppressed or reduced.

According to an aspect of the present invention, a base on which an LED chip is mounted, a reflector formed by molding a resin on the base so as to define a cavity around the LED chip, and a light-transmissive encapsulant formed in the cavity And, there is provided an LED package including a stepped structure formed to widen the bonding area with the encapsulant on the inner side of the reflector.

Preferably, the base includes plate-shaped first and second lead frames spaced apart from each other, and the resin forming the reflector fills the gap between the first lead frame and the second lead frame.

According to an embodiment of the present invention, the stepped structure may include stepped steps.

According to another embodiment of the invention, the reflector may comprise a first molding member and a second molding member which are molded in turn and separately. In this case, the stepped structure includes a stepped groove formed between the first molding member and the second molding member and filled by the encapsulant.

In addition, a groove filled with the resin forming the reflector may be formed on an upper surface of the base. The reflector may be made of an opaque epoxy or a PPA resin (most preferably, an opaque epoxy resin), and the encapsulant may be made of an epoxy resin having properties similar to those of the reflector.

According to the present invention, in a LED package in which a reflector having a cavity is molded on a base (particularly a leadframe) and an interface with the leadframe is formed in the cavity, the reflector fixed on the base fixes the encapsulant with a strong bonding force. By doing so, the interface separation phenomenon between the encapsulant and the lead frame is suppressed, which solves the problem of the bonding wire being separated by the encapsulation material separation and the lighting failure of the LED package.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, and the like of the components may be exaggerated for convenience. Like numbers refer to like elements throughout.

1 is a plan view showing an LED package according to an embodiment of the present invention, Figure 2 is a cross-sectional view taken along the line I-I of FIG.

1 and 2, the LED package 1 of the present embodiment includes a base 12 composed of plate-shaped first and second lead frames 12a and 12b. The first lead frame 12a and the second lead frame 12b are separated from each other by a gap G therebetween (see FIG. 3). The LED chip 2 is mounted on the first lead frame 12a. In addition, the electrode of the LED chip 2 and the second lead frame 12b are electrically connected by a bonding wire 3.

Reflectors 20 are formed on the upper surfaces of the first and second lead frames 12a and 12b, that is, the upper surface of the base 12 to partition the cavity 21 around the LED chip 2. At this time, the reflector 20 is formed by molding an opaque epoxy or PPA resin. In the present embodiment, the reflector 20 is formed on the upper surfaces of the first and second lead frames 12a and 12b by transfer molding using a mold. In addition, a substantially annular groove 121 (shown only in FIG. 2) is formed on the base 12 over the first and second lead frames 12a and 12b, and the groove 121 is a reflector ( At the time of molding 20, it is filled with resin to firmly fix between the lead frames 12a and 12b and the reflector 20.

On the other hand, the cavity 21 is filled with a translucent resin, for example, by a dotting method, and an encapsulant 30 for protecting the LED chip 2 and the like from the outside is formed. The encapsulant 30 is in contact with the first and second lead frames 12a and 12b to form an interface at a position in contact with the encapsulant 30.

In addition, the cavity of the reflector 20 has a structure in which the encapsulant 30 prevents the interface separation of the encapsulant 30 against a force falling from the first and second lead frames 12a and 12b. It is formed on the inner side. At this time, the structure is a stepped structure 24 formed on the inner surface of the cavity so that the junction area between the reflector 20 and the encapsulant 30 is increased. When the bonding force between the reflector 20 and the encapsulant 30 is increased by the stepped structure 24, the encapsulant 30 is not separated from the first and second lead frames 12a and 12b. Hold firmly to the encapsulant (30). In the present embodiment, the stepped structure 24 consists of stepped steps, which can be clearly seen from the one shown in FIG.

The step structure 24 is a stepped shape because the reflector's cavity 21 extends upwards, so that after molding (especially transfer molding), the mold used for the molding can be easily separated upwards. To make it work.

In addition, the gap G between the first leadframe 12a and the second leadframe 12b (see FIG. 3) is filled by the reflector 20 during the transfer molding, which is illustrated in FIG. And (b) will be clearly understood. FIG. 3A illustrates the bottom surfaces of the first and second lead frames 12a and 12b before transfer molding, and FIG. 3B illustrates the first and second lead frames 12a after transfer molding. 12b) is shown. The gap G shown to Fig.3 (a) is filled with resin which comprises the reflector 20, as shown to Fig.3 (b).

Hereinafter, an LED package according to another embodiment of the present invention will be described with reference to FIGS. 4 and 5. In the following description of the embodiment, the description will be omitted for the matters described in detail in the previous embodiment, and the member number used in the description of the previous embodiment is used as it is for components having the same function.

4 is a cross-sectional view of an LED package according to another embodiment of the present invention, and FIG. 5 illustrates a reflector forming process of the LED package shown in FIG. 4.

Referring to FIG. 4, the reflector 20 of the LED package 1 includes a first molding member 201 of the “L” type and a second molding member 202 of the “−” type. The first molding member 201 and the second molding member 202 are joined to each other in a continuous arrangement. In addition, a stepped structure 24 is formed on the inner surface of the cavity of the reflector 20 by the first molding member 201 and the second molding member 202 disposed continuously.

The stepped structure 24 includes a stepped groove 242 (see FIG. 5) formed between the first molding member 201 and the second molding member 202, and the stepped groove 242 is encapsulated. Ash 30 is filled. Therefore, the reflector 20 and the encapsulant 30 are structured to be engaged with each other by the step groove 242 and a portion of the encapsulant 30 filled therein, which reflects the reflector 20 and the encapsulant. Bonding force between the 30 is further strengthened, thereby more reliably preventing the interface separation phenomenon of the encapsulant 30 with respect to the first and second lead frames 12a and 12b.

Reflector molding in which the step grooves 242 are formed is possible by double molding (particularly, double transfer molding) in which the first and second molding members 201 and 202 are sequentially and individually formed. 5 is a view for explaining the double molding.

Referring to FIG. 5A, a first molding member constituting a lower part of the reflector 20 is formed on a base 12 composed of first and second lead frames 12a and 12b by molding, in particular, transfer molding. 201) is formed first. In this case, since a part of the cavity defined by the first molding member 201 is widened upward, the mold used for the transfer molding may be easily separated after molding.

Next, as shown in FIG. 5B, a second molding member 202 is formed on the first molding member 201. Since the second molding member 202 is made of the same material as or similar to that of the first molding member 201, the second molding member 202 may be joined by molding alone. By forming the second molding member 202, a step groove 242 may be formed between the first molding member 201 and the second molding member 202.

Before the formation of the second molding member 202, a portion of the encapsulant 30 (see FIG. 4) may be previously formed in the cavity defined by the first molding member 201, or the blocking material may be filled. The mold used in the second molding member 202 can be easily separated from the cavity of the reflector despite the presence of the step groove 242.

4 and 5 show a reflector 20 comprising only two molding members 201 and 202 for the formation of a stepped structure 24 with one stepped groove 242, but three or more moldings. The design of the reflector including the stepped structure having two or more stepped grooves using the member may also be considered.

When the material of the reflector 20 is made of an opaque epoxy or PPA resin containing a reflective color (for example, white), and the material of the encapsulant 30 is made of an epoxy resin having similar properties to that of the reflector resin, the reflector 20 ) And the encapsulant 30 are firmly bonded. However, the present invention should not be limited only by the material of the reflector or the encapsulant, and various kinds of resins may be used as the material of the reflector or encapsulant.

1 is a plan view showing an LED package according to an embodiment of the present invention.

2 is a sectional view taken along the line I-I of FIG.

3 (a) and 3 (b) are diagrams illustrating a bottom surface of a base composed of a first lead frame and a second lead frame divided into before and after the reflector formation.

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

5A and 5B are views for explaining a process of forming the reflector of the LED package shown in FIG.

Claims (7)

A base on which the LED chip is mounted; A reflector formed by molding a resin on the base to define a cavity around the LED chip; An encapsulant made of a light-transmissive resin material formed in the cavity; A stepped structure formed to widen the bonding area with the encapsulant on the inner side of the reflector, The reflector includes a first and a second molding member, the LED package including a step groove which is located between the first and second molding member is filled by the encapsulant. The method of claim 1, wherein the base includes a plate-like first and second lead frame spaced apart from each other, the resin forming the reflector, characterized in that the gap between the first lead frame and the second lead frame. LED package. The LED package of claim 1, wherein the stepped structure includes stepped steps. delete delete The LED package according to claim 1, wherein a groove is formed on the upper surface of the base by resin forming the reflector. The LED package according to claim 1, wherein the reflector is made of opaque epoxy or PPA resin, and the encapsulant is made of epoxy resin.

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