KR20060079740A - Leadframe having a heat sink support ring, fabricating method of the light emitting diode package using the same and light emitting diode package fabrecated by the method - Google Patents

Abstract

A lead frame having a heat sink support ring, a light emitting diode package employing the same, and a method of manufacturing a light emitting diode package using the same are disclosed. The leadframe has a support ring for supporting the heat sink. The outer frame is spaced apart from the support ring to surround the support ring. At least two connection terminals connect the outer frame and the support ring at opposite sides of the support ring. In addition, at least two lead terminals extend toward the support ring in the outer frame. The lead terminals are spaced apart from the support ring. Accordingly, after the heat sink is inserted into the lead frame, the package body may be formed by using an insert molding technique, thereby easily providing a light emitting diode package having excellent heat dissipation characteristics.

Lead frame, heat sink, package body, lead terminal, insert molding technology

Description

Lead frame having a heat sink support ring, a method of manufacturing a light emitting diode package using the same, and a light emitting diode package manufactured by the same BY THE METHOD}

1 is a perspective view for explaining a lead frame according to an embodiment of the present invention.

2 is a flowchart illustrating a light emitting diode package according to an embodiment of the present invention.

3 to 9 are views for explaining a method of manufacturing a light emitting diode package according to the process flow chart of FIG.

(A brief description of the main symbols in the drawings)

10: leadframe, 11: outer frame,

13: heatsink support ring, 15a, 15b: connectors,

17a, 17b, 17c, 19a, 19b, 19c: lead terminals,

20: heatsink, 21: base,

23: projection, 23a: support ring receiving groove,

30, 30a: package body, 40, 41, 43, 45: light emitting diode die

The present invention relates to a lead frame, a method of manufacturing a light emitting diode package using the lead frame, and a light emitting diode package manufactured by the method, and more particularly, to prevent the heat sink from being separated from the package body. A lead frame having a heat sink support ring capable of fixing a heat sink to a lead frame prior to forming the package body using the technique, a method of manufacturing a light emitting diode package using the lead frame, and a light emitting diode package manufactured by the same will be.

In order for a light emitting diode (LED) to be used for a purpose such as an illuminating light source, it is required to have luminous power of several tens of lumens or more. The light output of the light emitting diode is generally proportional to the input power. Therefore, a high light output can be obtained by increasing the power input to the light emitting diode. However, increasing the input power increases the junction temperature of the light emitting diodes. Increasing the junction temperature of a light emitting diode leads to a decrease in photometric efficiency, which indicates the extent to which input energy is converted into visible light. Thus, there is a need for a structure for preventing an increase in junction temperature of a light emitting diode according to an increase in input power.

A light emitting diode package having such a structure is disclosed in US Pat. No. 6,274,924 (B1) (named surface mount LED package). This allows the LED die to be maintained at a low junction temperature because the LED die is thermally coupled onto the heat sink. Therefore, a relatively large input power can be supplied to the LED die, thereby obtaining a high light output.

However, such a structure, that is, a light emitting diode package (hereinafter referred to as an LED package) capable of obtaining high light output with a large input power has not been proposed in various structures and shapes until recently. This is because the LED package has a technical difficulty for commercialization despite its simple configuration, and in particular, the thermal analysis generated from the package itself is not easy and there are few experts, so the development is actually limited. However, the LED package is to be applied not only for lighting but also for large TVs or displays, and its application field is very wide in the future, so that various LED packages having excellent heat dissipation characteristics of structures and shapes different from conventional products are required. It is true.

On the other hand, such a conventional LED package has a structure in which lead terminals and heat sinks are separated, and they have a structure in which they are coupled to each other through a housing made of an insulating material, and thus, manufacturing thereof is relatively difficult.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an LED package having excellent heat dissipation characteristics and preventing an increase in junction temperature of an LED die even when a large input power is input, thereby obtaining a high light output.                         

Another object of the present invention is to provide an LED package that can be easily manufactured in a structure in which a lead terminal and a heat sink are mutually coupled.

Another technical problem to be achieved by the present invention is to provide a lead frame that can easily manufacture an LED package.

In order to achieve the above technical problem, the present invention provides a lead frame having a heat sink support ring, a light emitting diode package manufacturing method using the same, and a light emitting diode package manufactured by the method.

The leadframe according to one aspect of the invention has a heatsink support ring for supporting the heatsink. The outer frame is spaced apart from the support ring to surround the support ring. Meanwhile, at least two connection terminals connect the outer frame and the support ring at opposite sides of the support ring. In addition, at least two lead terminals extend toward the support ring in the outer frame. The lead terminals are spaced apart from the support ring. Accordingly, after inserting the heat sink into the lead frame, it is possible to form the package body using the insert molding technology, it is possible to easily manufacture the LED package.

Preferably, the at least two lead terminals are disposed at one or more sides on opposite sides of the support ring. In addition, the lead terminals may be disposed in a direction orthogonal to the connection terminals.

According to another aspect of the present invention, a method of manufacturing a light emitting diode package includes preparing a lead frame and a heat sink. The lead frame has a heat sink support ring for supporting the heat sink. The outer frame is spaced apart from the support ring to surround the support ring. Meanwhile, at least two connection terminals connect the outer frame and the support ring on opposite sides of the support ring to fix the support ring to the outer frame. In addition, at least two lead terminals extend toward the support ring in the outer frame. The lead terminals are spaced apart from the support ring. On the other hand, the heat sink is prepared to be inserted and fixed to the support ring. The heat sink is inserted into the support ring and fixed. Subsequently, an insert molding technique is used to form a package body that molds and supports portions of the heat sink and the lead terminals and connecting terminals around the heat sink. In this case, the package body has an opening that exposes an upper end portion of the heat sink and portions of the lead terminals. Accordingly, the LED package may be manufactured in a structure in which the heat sink and the lead terminal are coupled to each other.

A light emitting diode package according to another aspect of the present invention includes a heat sink support ring. The heat sink is inserted into the heat sink support ring. On the other hand, at least two lead terminals are disposed on both sides of the support ring spaced apart from the support ring and the heat sink. In addition, a package body molds and supports the heat sink and the lead terminals. The package body has an opening that exposes an upper end of the heat sink and portions of the lead terminals. Accordingly, the heat sink and the support ring are combined to facilitate the manufacture of the LED package, and the heat sink can be prevented from being separated from the package body.

In addition, the bottom surface of the heat sink is exposed to the outside. Thus, heat is released through the bottom surface of the heat sink.

On the other hand, the heat sink may include a base and a protrusion protruding upward from the center portion of the base. At this time, the protrusion is inserted into the support ring. According to this embodiment, the size of the light emitting diode package can be reduced while maintaining the surface area of the heat dissipation surface.

In addition, the heat sink may further include a support ring receiving groove for fastening to the support ring on the side of the protrusion. The support ring is fastened to the receiving groove to strongly fix the heat sink.

The package body is a plastic resin formed by injection molding the heat sink into the support ring. Therefore, a package body having a complicated structure can be easily formed, and the package body and the heat sink are strongly coupled.

The LED package further includes at least one LED die mounted on an upper surface of the heat sink and bonding wires electrically connecting the LED die and the lead terminals.

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

1 is a perspective view for explaining a lead frame 10 according to an embodiment of the present invention.

Referring to FIG. 1, the lead frame 10 has a heat sink support ring 13 through which a heat sink can be inserted. The support ring 13, as shown, may be a circular ring shape, but is not limited to this, it may be a polygonal ring shape.

On the other hand, the outer frame 11 surrounds the support ring 13. The outer frame 11 is spaced apart from the support ring 13. As illustrated, the outer frame 11 may be square, but is not limited thereto, and may be a circular or other polygon.

The outer frame 11 and the support ring 13 are connected by at least two connection terminals 15a and 15b. The connecting terminals 15a and 15b are positioned at opposite sides of the support ring 13 to fix the support ring 13 to the outer frame 11. In addition to the connection terminals 15a and 15b, additional connection terminals may connect the support ring 13 and the outer frame 11.

In addition, at least two lead terminals 17a, 17b, 17c, 19a, 19b, and 19c extend from the outer frame 11 toward the support ring 13. However, the lead terminals are spaced apart from the support ring 13. As shown, the lead terminals 17a, 17b, 17c, 19a, 19b, and 19c may have end portions having a larger area near the support ring 13. On the other hand, it is preferable that the lead terminals are arranged on opposite sides of the support ring 13.

Although the number of lead terminals is determined by the type and number of LED dies to be mounted and the bonding wire connection method, the lead frame 10 preferably has a large number of lead terminals so that they can be used in various cases. As shown, the lead terminals are arranged in a direction orthogonal to the connection terminals 15a and 15b, and a large number of lead terminals may be arranged in the same direction.

Meanwhile, although six lead terminals are shown in FIG. 1, fewer lead terminals may be disposed and additional lead terminals may be further disposed. The additional lead terminals may be arranged in the same direction as the connection terminals 15a and 15b.

The lead frame 10 according to an embodiment of the present invention may be manufactured by pressing a phosphor bronze plate made of copper alloy using a die technique. Meanwhile, although one lead frame 10 is illustrated in FIG. 1, a plurality of lead frames 10 may be manufactured and aligned in one phosphor bronze plate. In particular, a plurality of lead frames 10 manufactured in one phosphor bronze plate are used to mass-produce a light emitting diode package.

2 is a process flowchart illustrating a method of manufacturing a light emitting diode package according to an embodiment of the present invention, Figures 3 to 9 are a perspective view and a plan view for explaining a method of manufacturing a light emitting diode package according to the process flow chart admit.

Referring to FIG. 2, the lead frame 10 described with reference to FIG. 1 is prepared (S01).

The lead frame 10 may be manufactured by pressing a phosphor bronze plate, as described above, and a plurality of lead frames 10 may be manufactured and aligned in the same phosphor bronze plate.

2 and 3, a heat sink 20 that can be inserted into and fixed to the support ring 13 of the lead frame 10 is prepared. The heat sink 20 has an upper surface on which a light emitting diode die can be mounted. The upper surface of the heat sink 20 is preferably smaller than the inner diameter of the support ring 13 to be easily inserted into the support ring 13, the outer diameter of the side surface of the heat sink 20 is the support ring 13 It is preferable that it is larger than the inner diameter of.

In addition, the heat sink 20 may have a support ring receiving groove 23a for fastening to the support ring 13. Moreover, the support ring receiving groove 23a may be provided as a spiral groove to be easily fastened to the support ring 13.

On the other hand, the heat sink 20 may have a base portion 21 and a protrusion 23 protruding upward from the center portion of the base portion. At this time, the support ring receiving groove (23a) is located on the side of the protrusion (23). The base 21 and the protrusion 23 may be cylindrical, as shown, but is not limited thereto, and may be polygonal. The protrusion 23 may have a shape similar to the inner shape of the support ring 13, but is not limited thereto. That is, the support ring 13 is a circular ring shape, the protrusion 23 may be a rectangular cylinder.

The heat sink 20 may be manufactured by using a press working technique or a molding technique with a high thermal conductivity metal or a thermally conductive resin. In addition, the heat sink 20 is manufactured using a process separate from the lead frame 10. Therefore, the step (S01) of preparing the lead frame 10 and the step (S03) of preparing the heat sink 20 may be reversed or may be performed at the same time.

2 and 4, the heat sink 20 is inserted into and fixed to the support ring 13 of the lead frame 10 (S05). Since the outer diameter of the side surface of the heat sink 20 is larger than the inner diameter of the support ring 13, the heat sink 20 may be forcibly inserted and fixed to the support ring 13.

On the other hand, if the support ring receiving groove (13a) is formed, the support ring 13 is accommodated in the support ring receiving groove (13a) to support the heat sink (20). At this time, a portion of the support ring 13 is accommodated in the support ring receiving groove 13a, and the rest is preferably protruded to the outside of the protrusion 23 as shown. In addition, when the support ring receiving groove 13a is a spiral groove, the heat sink 20 may be rotated to be fastened to the support ring 13.

2 and 5A, after fixing the heat sink 20 to the lead frame 10, the package body 30 is formed using an insert molding technique (S07). The package body 30 may be formed by injection molding a thermosetting resin.

The package body 30 is formed around the heat sink 20 to support the support ring 13, the connection terminals 15a and 15b, the lead terminals 17a, 17b, 17c, 19a, 19b and 19c and the heat sink. Support 20. Some of the connection terminals and the lead terminals protrude out of the package body 30. In addition, the package body 30 has an opening for exposing the upper end of the heat sink 10 and the lead terminals.

As shown in FIG. 5A, a portion of the support ring 13 and the connection terminals 15a and 15b may be exposed by the opening. Accordingly, a groove is formed in the upper portion of the package body 30. Alternatively, as shown in FIG. 5B, the package body 30a may cover most of the heat sink 20 except for the upper end of the heat sink 20 and may expose only a portion of the lead terminals. Therefore, the opening may be formed in plural.

Also in this case, it is preferable that a groove formed on the side of the package body is formed in the upper portion of the package body 30a as shown.

In addition, the lower surface of the heat sink 20 is exposed to the outside. In addition, the side surface of the base portion 21 may be exposed. Accordingly, heat dissipation through the heat sink 20 can be promoted.

Meanwhile, the package body 30 may be cylindrical, as shown in FIGS. 5A and 5B, but is not limited thereto, and may be a polygonal cylinder such as a rectangular cylinder.

After the heat sink 20 is coupled to the lead frame 10, a thermosetting resin is injection molded to form the package body 30, so that the heat sink 20 and the package body 30 are strongly coupled to each other.

2 and 6A, the connecting terminals 15a and 15b protruding out of the package body 30 are cut and removed (S09). As a result, the disconnected connecting terminals 16a and 16b remain in the package body 30, and the connecting terminals and the support ring 13 are separated from the heat sink 20 by the package body 30. Prevent further

Meanwhile, while cutting the connection terminals, the other lead terminals may be cut and removed together except for the lead terminals to be used to supply current among the lead terminals protruding out of the package body 30. For example, as shown in FIG. 6B, when only two lead terminals 17c and 19c are needed, the remaining lead terminals 17a, 17b, 19a and 19b are cut off and removed. In addition, as shown in FIG. 6C, if four lead terminals 17a, 17c, 19a, and 19c are needed, the remaining lead terminals 17b and 19b are cut and removed.

Cutting and removing the lead terminals is a process performed when a larger number of lead terminals are provided in the lead frame 10 than the lead terminals required in the LED package. Therefore, when the number of lead terminals required in the LED package and the number of lead terminals provided in the lead frame 10 coincide, the process of cutting and removing the lead terminals is not performed. In addition, even if the extra lead terminals remain, it does not affect the operation of the LED package. Therefore, it is not necessary to cut and remove the extra lead terminals.

2 and 7, a light emitting diode die 40 is mounted on an upper surface of the heat sink 20. The LED die 40 may be a one-bond die having electrodes on the top and bottom surfaces, or a two-bond die having two electrodes on the top surface.

When the light emitting diode die 40 is a one-bond die, the heat sink 20 is preferably made of an electrically conductive metal material. In this case, the die 40 is made of the heat through an electrically conductive adhesive such as silver epoxy. It is mounted on the sink 20. In contrast, when the LED dies 40 mounted on the heat sink 20 are all two bond dies, the heat sink 20 does not need to be electrically conductive, and the LED die 40 is formed of silver. In addition to the epoxy may be mounted on the heat sink 20 through various thermally conductive adhesives.

Meanwhile, a plurality of light emitting diode dies 40 mounted on the heat sink 20 may be provided. In addition, the plurality of light emitting diode dies 40 may be light emitting diode dies that emit light having different wavelengths. For example, as shown in FIG. 7, three light emitting diode dies 40 may be mounted. In this case, the light emitting diode dies 40 may be light emitting diode dies that emit light of red color, green color, and blue color, respectively. Accordingly, the light emitting diode package may emit light of all colors using the light emitting diode dies 40.

2 and 8A, the LED dies 41, 43, and 45 and the lead terminals 17a, 17b, 17c, 19a, 19b, and 19c are electrically connected to each other by bonding wires (S13). When the LED dies 41, 43 and 45 are all two bond dies, each LED die is connected to two lead terminals through two bonding wires. Meanwhile, as illustrated, the LED dies 41, 43, and 45 may be electrically connected to a pair of lead terminals that are different from each other. In addition, one common lead terminal (eg, 17b) and LED dies may be connected to each other by bonding wires, and different lead terminals (eg, 19a, 19b, and 19c) positioned opposite to the common lead terminal may be connected to each other. The light emitting diode dies may be connected to other bonding wires. In this case, the LED dies may be driven by different currents.

Meanwhile, as shown in FIG. 8B, the one bond die 41a and the two bond dies 43 and 45 may be mounted together. At this time, one of the lead terminals 17b is electrically connected to the heat sink 20 through a bonding wire. Accordingly, the lead terminal 17b is electrically connected to the bottom surface of the one bond die 41a through the bonding wire and the heat sink 20. Combinations of one-bond dies and two-bond dies vary, and a variety of ways of connecting the bonding wires may be adopted for each combination.

In addition, a method of connecting the lead terminals and the LED dies may be variously selected, and a plurality of LED dies may be connected in series, in parallel, or in parallel.

Meanwhile, after connecting the LED dies 41, 43, 45 and the lead terminals with bonding wires, the LED dies 41, 43, 45 are sealed using an encapsulant (not shown). (S15). The encapsulant may fill the opening of the package body 30 to seal the LED dies and the bonding wires.

In addition, the encapsulant may contain a phosphor. For example, the phosphor may be a phosphor that converts blue light into yellow or green and red. Therefore, when a light emitting diode die emitting blue color is mounted on the heat sink 20, part of the light emitted from the light emitting diode die is converted into yellow, green, and red colors so that white light is emitted to the outside. A light emitting diode package can be provided. In addition, the encapsulant may further contain a diffusing agent. The diffusing agent disperses the light emitted from the light emitting diode dies to prevent the light emitting diode dies and the bonding wires from being observed from the outside and allows the light to be emitted uniformly to the outside.

After sealing the LED dies with the encapsulant, a lens (not shown) is attached to the package body 30 (S17). The lens is used to emit light within a certain direction angle, and may be omitted if it is not necessary to use the lens. In particular, the encapsulant may be cured into a lens shape to serve as a lens, and the process of attaching the lens is omitted.

2 and 9, the lead terminals 17a, 17b, 17c, 19a, 19b, and 19c are cut and bent from the outer frame 11 (S19). As a result, a light emitting diode package capable of surface mounting is completed. On the other hand, the step (S09) of cutting and removing the connection terminal may be performed together in step (S19).

Hereinafter, a light emitting diode package according to an aspect of the present invention will be described in detail with reference to FIG. 9.

Referring back to FIG. 9, the light emitting diode package includes a heat sink support ring 13. The support ring 13 is made of a copper alloy such as phosphor bronze. The support ring 13, as shown, may be a circular ring shape, but is not limited to this, it may be a polygonal ring shape. The connection terminals 16a and 16b cut out of the support ring 13 are positioned to extend. The cut connection terminals 16a and 16b may be located at opposite sides of the support ring 13.

The heat sink 20 as described above with reference to FIG. 3 is inserted into the support ring 13.

Meanwhile, at least two lead terminals 17a, 17b, 17c, 19a, 19b, and 19c are spaced apart from the support ring 13 and the heat sink 20 and disposed on both sides of the support ring. The lead terminals may be bent to allow surface mounting.

In addition, the package body 30 molds and supports the heat sink 20 and the lead terminals. The package body 30 has an upper portion of the heat sink 20 and an opening for exposing portions of the lead terminals. On the other hand, a part of the lead terminal is protruded to the outside through the side wall of the package body 30.

As described with reference to FIG. 5A, a portion of the support ring 13 and the connection terminals 15a and 15b may be exposed by the opening. Accordingly, a groove is formed in the upper portion of the package body 30. In addition, as described with reference to FIG. 5B, the package body (30a of FIG. 5B) may cover most of the heat sink 20 except for the upper end of the heat sink 20 and may expose only portions of the lead terminals. Therefore, the opening may be formed in plural. Also in this case, the package main body 30a preferably has a groove surrounded by the side wall of the package main body, as shown in Fig. 5B.

The package body 30 is a plastic resin formed by injection molding a thermosetting resin after inserting and fixing the heat sink 20 to the support ring 13.

Meanwhile, light emitting diode dies 41, 43, and 45 are mounted on the top surface of the heat sink 20. The light emitting diode dies shown in FIG. 9 represent two bond dies, but are not limited thereto. The light emitting diode dies may be one bond dies, and may be a combination of one bond die and two bond dies.

The light emitting diode dies are electrically connected to the lead terminals through bonding wires. When the LED dies are two bond dies, each LED die is electrically connected to two lead terminals through two bonding wires. Meanwhile, when at least one of the light emitting diode dies is a one-bond die, the heat sink is electrically connected to at least one lead terminal through a bonding wire.

The method of connecting the LED dies and the lead terminals may vary, and may be selected according to the characteristics of the LED package required.

Meanwhile, an encapsulant (not shown) covers and seals the LED dies. The encapsulant fills the grooves formed in the upper portion of the package body 30. In addition, the encapsulant may contain a phosphor and / or a diffusing agent. On the other hand, the encapsulant may have a lens shape.

In addition, a lens (not shown) may be attached to the package body 30.

According to embodiments of the present invention, it is possible to provide a light emitting diode package having excellent heat dissipation characteristics by adopting a heat sink to obtain a high light output. In addition, after the heat sink is fixed to the lead frame, the package body may be formed using an insert molding technique, so that the LED package may be easily manufactured in a structure in which the lead terminal and the heat sink are coupled to each other. In addition, the heat sink may be fixed before the package body is formed, thereby providing a lead frame that facilitates manufacture of a light emitting diode package.

Claims (11)

A support ring for supporting the heat sink; An outer frame spaced apart from the support ring to surround the support ring; At least two connection terminals connecting the support ring and the outer frame at opposite sides of the support ring; And a heatsink support ring extending from the outer frame toward the support ring and including at least two lead terminals spaced apart from the support ring. The lead frame according to claim 1, wherein the at least two lead terminals are disposed at least one on each of opposite sides of the support ring. The lead frame according to claim 2, wherein the lead terminals are disposed in a direction orthogonal to the connection terminals. Heat sink support ring; A heat sink inserted into the support ring; At least two lead terminals spaced apart from the support ring and the heat sink and disposed at both sides of the support ring; And a package body configured to support the heat sink and the lead terminals, the package body having an upper end of the heat sink and an opening exposing portions of the lead terminals. The light emitting diode package according to claim 4, wherein the heat sink includes a base portion and a protrusion protruding upward from a center portion of the base portion, and the protrusion is inserted into the support ring. The light emitting diode package of claim 5, wherein the heat sink further comprises a support ring receiving groove for fastening to the support ring on the side of the protrusion. The light emitting diode package according to claim 4, wherein the package body is a plastic resin formed by injection molding a thermosetting resin after inserting the heat sink into the support ring. The semiconductor device of claim 4, further comprising: at least one light emitting diode die mounted on an upper surface of the heat sink; And bonding wires electrically connecting the LED die and the lead terminals. Preparing a lead frame of any one of claims 1 to 3, Prepare a heat sink that can be inserted into the support ring and fixed, Insert and fix the heat sink to the support ring, An insert molding technique is used to form a package body for molding and supporting portions of the heat sink and the lead terminals and connecting terminals around the heat sink, wherein the package body is formed of the upper end of the heat sink and the lead terminals. A method of manufacturing a light emitting diode package having an opening for exposing portions. The method of claim 9, further comprising cutting and removing connection terminals external to the package body. 10. The method of claim 9, wherein mounting at least one light emitting diode die on an upper surface of the heat sink and forming bonding wires electrically connecting each light emitting diode die to two of the lead terminals. Method for manufacturing a light emitting diode package further comprising.

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