TWI464929B - Light source module with enhanced heat dissipation efficiency and embedded package structure thereof - Google Patents

Description

Light source module for improving heat dissipation efficiency and embedded package structure thereof

The invention relates to a light source module, and in particular to a light source module for improving heat dissipation efficiency and an embedded package structure thereof.

Generally, the bottom of the light-emitting element is thermally insulated by a heat sink, but the heat generated by the light-emitting element must pass through a solder paste, an insulating glue (such as PP glue), and a backing on the circuit substrate to reach the heat sink. Among the three layers of materials, the thermal resistance of the insulating rubber is the largest, and efforts should be made to minimize the use of the insulating adhesive. However, in the thermoelectric separation package structure, the light-emitting and non-conductive insulating glue is conventionally used to electrically isolate the light-emitting element from the heat sink. Therefore, the conventional thermoelectric separation package structure cannot solve the problem of poor heat dissipation. In addition, the package structure assembled on the heat sink often causes the assembler's finger to touch the encapsulant, causing the surface to be stressed and causing the internal gold wire to be broken or damaged. Therefore, the package structure should be avoided to be touched during assembly. The opportunity to arrive.

The invention relates to a light source module for improving heat dissipation efficiency and an embedded package structure thereof, which can directly transmit heat generated by a light-emitting element to a heat sink below to reduce thermal resistance. In addition, the embedded package structure can be embedded in the recess of the heat sink, thereby effectively reducing the chance of the package structure being touched during assembly.

According to an aspect of the invention, a light source module for improving heat dissipation efficiency is proposed. The light source module comprises a light emitting component, a circuit layer, a lead frame, a heat conductive material layer and a heat sink. The lead frame is electrically connected between the light emitting element and the circuit layer. The layer of thermally conductive material is attached to the bottom of the leadframe and the layer of thermally conductive material is electrically insulated from the leadframe. The heat sink has a recess for receiving the light emitting element and the lead frame, wherein the heat conductive material layer is located at the bottom of the groove such that the heat sink is in thermal contact with the bottom of the lead frame by the layer of heat conductive material.

According to another aspect of the present invention, an embedded package structure is provided, which is disposed in a recess, and a pad is disposed on an outer side of the recess. The embedded package structure includes a light emitting component, a lead frame, and a glue. The lead frame is electrically connected to the light emitting element. The recess is configured to receive the light emitting component and the lead frame, and the upper end of the lead frame extends to the outside of the recess and is electrically connected to the pad. The sealant covers the light-emitting component and a part of the lead frame, wherein the lower end of the lead frame extends into the sealant and is electrically connected to the light-emitting element.

In order to better understand the above and other aspects of the present invention, the preferred embodiments are described below, and in conjunction with the drawings, the detailed description is as follows:

The light source module for improving heat dissipation efficiency of the embodiment and the embedded package structure thereof are processed on a heat sink (for example, an aluminum plate) to form a groove-shaped groove, and surface treatment is performed on the lower surface of the groove to form A layer of thermally conductive material is in the recess. With the layer of thermally conductive material, the heat generated by the illuminating element can be directly conducted to the heat sink without passing through the insulating layer to reduce the generation of thermal resistance. In addition, the embedded package structure adopts an upwardly bent lead frame, so that the lead frame can be buried in the groove of the heat sink and can be electrically connected between the light emitting element and the circuit layer by soldering. Therefore, the embedded package structure can be appropriately protected to reduce the chance of being touched during assembly.

Please refer to FIGS. 1A-1E for a schematic diagram of a processing flow of a heat sink of a light source module according to an embodiment. The processing flow includes the following steps (1) to (4). In FIG. 1A, step (1) forms a circuit layer 112 and an insulating layer 114 on the upper surface of the heat sink 116. The insulating layer 114 is located between the circuit layer 112 and the heat sink 116 to electrically isolate the circuit layer 112 from the heat sink 116. In FIG. 1B, step (2) removes a portion of the insulating layer 114 and a portion of the fins 116 by machining or etching to form a recess 116a. The pads 112a, 112b of the circuit layer 112 are located outside of the recess 116a. In Fig. 1C, step (3) forms a metal layer 118 (e.g., copper or nickel) at the bottom of the recess 116a. In FIG. 1D, step (4) forms a layer of thermally conductive material 120 on metal layer 118, and a portion of thermally conductive material layer 122 is formed on pads 112a, 112b of circuit layer 112. In an embodiment, the layer of thermally conductive material 120 is formed, for example, in a coating manner at the bottom of the recess 116a. The material of the heat conductive material layer 120 includes tin, for example, a low-melting tin-lead alloy or a tin-silver-copper alloy. In addition, when the heat conductive material layer 120 is coated on the bottom of the groove 116a with a screen, a portion of the heat conductive material layer 122 may be simultaneously coated on the pads 112a, 112b as a solder material layer. In addition, when the material of the heat sink 116 is aluminum, since the bonding ability of the copper (metal layer 118) and the tin (heat conductive material layer 120) is greater than the bonding ability of the aluminum (the heat sink 116) and the tin (the heat conductive material layer 120), This embodiment can increase the bonding ability of the heat sink 116 and the heat conductive material layer 120 by bonding copper (metal layer 118) between the heat conductive material layer 120 and the heat sink 116.

In addition, referring to FIG. 1E, in the above processing flow, after the step (4), a solder resist layer 124 may be further coated on the insulating layer 114. The solder resist layer 124 covers the insulating layer 114 and exposes a portion of the thermally conductive material layer 122 (a layer of solder material) on the pads 112a, 112b and a layer of thermally conductive material 120 at the bottom of the recess 116a, as shown in FIG. 2A.

Next, please refer to FIGS. 2A and 2B , which are respectively assembled diagrams of the embedded package structure 102 according to an embodiment. The embedded package structure 102 can be assembled into the light source module 100 by being assembled into the recess 116a of the heat sink 116. The heat sinks 116 of the light source module 100 are formed with pads 112a and 112b, an insulating layer 114, a metal layer 118 and a heat conductive material layer 120, which can be fabricated through the processing flow of FIGS. 1A to 1D. Let me repeat. The embedded package structure 102 includes a light emitting element 110, a lead frame 130, and a glue 140. The lead frame 130 is electrically connected between the light emitting element 110 and the pads 112a, 112b. In addition, the heat sink 116 has a recess 116a for receiving the light emitting element 110 and the lead frame 130, wherein the heat conductive material layer 120 is located at the bottom of the recess 116a, so that the heat sink 116 is separated by the heat conductive material layer 120. The bottom of the lead frame 130 is in thermal contact. In addition, the embedded package structure 102 further includes at least one wire 142 electrically connected between the light emitting element 110 and the lead frame 130 to transmit signals.

In the above embodiment, the embedded package structure 102 adopts the upwardly bent lead frame 130, so that the lead frame lower end 130c and the lead frame middle end 130b can be buried in the groove 116a of the heat sink 116. The lead frame upper end 130a extends to the outside of the recess 116a and is electrically connected by bonding the solder material layer to the pads 112a, 112b. In addition, the encapsulant 140 encloses the light emitting element 110 and a portion of the lead frame 130 such that the lead frame lower end 130c extends into the encapsulant 140 and is located around the light emitting element 110. In one embodiment, the light-emitting element 110 is electrically connected to the lower end 130c of the lead frame by a pair of wires 142 to electrically illuminate the light-emitting element 110.

In the above embodiment, the bottom of the lead frame 130 has, for example, a wafer holder 134, and the light-emitting element 110 is disposed on the wafer holder 134, and the upper end 130a of the lead frame extends from the side of the wafer holder 134 in an L shape beyond the sealant 140. And exposed on the top surface of the sealant 140. As shown in FIG. 2B, when the embedded package structure 102 is buried in the recess 116a, the wafer holder 134 at the bottom is directly in contact with the heat conductive material layer 120, and the heat conductive material layer 120 is, for example, solder paste or other metal. The heat generated by the light-emitting element 110 is directly transmitted to the heat sink 116 without passing through the insulating layer 114 to reduce the generation of thermal resistance. In addition, the encapsulant 140 of the embedded package structure 102 does not protrude from the outside of the heat sink 116, but is embedded in the recess 116a, and is not easy to touch during assembly, so that the inner lead 142 can be protected from being pressed. Avoid breakage or damage.

In the above embodiment, the encapsulant 140 is pre-coated with the light-emitting component 110 and a portion of the lead frame 130 before assembly to form an embedded package structure 102, and then the embedded package structure 102 is assembled into the recess 116a to form An integrated light source module 100. In another embodiment, the encapsulant 140 can be filled into the recess 116a after being assembled into the light source module 100, and the light emitting component 110 and the partial lead frame 130 are coated by curing to form an embedded package. Structure 102. In addition, the sealant 140 may have the shape and function of a lens, such as having a convex surface, a concave surface, or a combination thereof, thereby changing the light exit angle of the light emitted by the light emitting element 110.

The light source module and the embedded package structure thereof for improving heat dissipation efficiency disclosed in the above embodiments of the present invention adopt an upwardly bent lead frame, so that the lead frame can be buried in the groove of the heat sink, and can be The solder is soldered and electrically connected between the light emitting element and the circuit layer. Therefore, the embedded package structure can be appropriately protected to reduce the chance of being touched during assembly. In addition, after the light-emitting element is buried, the overall thickness of the light source module is significantly reduced, which is more suitable for thinning. The heat generated by the light-emitting element (for example, a high-power light-emitting diode element) of the present embodiment can be directly transmitted to the underlying heat conductive material layer and the heat sink, insofar as the thermal resistance of the insulating layer of the conventional circuit substrate is too high. It does not need to pass through the insulating layer, so the heat resistance can be effectively reduced to improve the heat dissipation efficiency of the light source module.

In conclusion, the present invention has been disclosed in the above embodiments, but it is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100. . . Light source module

102. . . Embedded package structure

110. . . Light-emitting element

112. . . Circuit layer

112a, 112b. . . Pad

114. . . Insulation

116. . . heat sink

116a. . . Groove

118. . . Metal layer

120. . . Thermally conductive material layer

122. . . Part of the layer of thermal conductive material (welding material layer)

124. . . Solder mask

130. . . Lead frame

130a. . . Upper end of lead frame

130b. . . Middle end of lead frame

130c. . . Lower end of lead frame

134. . . Wafer holder

140. . . Plastic closures

142. . . wire

1A-1E are schematic diagrams showing a processing flow of a heat sink of a light source module according to an embodiment.

2A and 2B are respectively assembled schematic views of an embedded package structure according to an embodiment.

100. . . Light source module

102. . . Embedded package structure

110. . . Light-emitting element

112a, 112b. . . Pad

114. . . Insulation

116. . . heat sink

116a. . . Groove

118. . . Metal layer

120. . . Thermally conductive material layer

122. . . Part of the layer of thermal conductive material (welding material layer)

124. . . Solder mask

130. . . Lead frame

130a. . . Upper end of lead frame

130b. . . Middle end of lead frame

130c. . . Lower end of lead frame

134. . . Wafer holder

140. . . Plastic closures

142. . . wire

Claims (11)

A light source module for improving heat dissipation efficiency, the light source module includes: a heat sink having a groove; a circuit layer disposed on an outer side of the groove; and an embedded package structure disposed in the groove The embedded package structure includes: a light-emitting component; a lead frame disposed in the embedded package structure corresponding to the recess and electrically connected between the light-emitting component and the circuit layer, the recess is configured to receive the a light-emitting element and the lead frame, the upper end of the lead frame extends to the outside of the groove, and is electrically connected to the circuit layer; a glue covers the light-emitting element and a part of the lead frame, wherein the lower end of the lead frame extends to The sealing material is electrically connected to the light emitting element; and a wafer holder is disposed at the bottom of the lead frame, and the light emitting element is disposed on the wafer holder; a layer of heat conductive material is located at the bottom of the groove and is connected to The wafer holder is such that the heat sink is in thermal contact with the wafer holder by the layer of thermally conductive material. The light source module of claim 1, further comprising an insulating layer between the circuit layer and the heat sink, the insulating layer being located outside the groove. The light source module of claim 2, further comprising a solder resist layer coated on the insulating layer and exposed on the outer side of the recess. The light source module of claim 2, wherein the circuit layer comprises at least one pad disposed on an outer side of the groove, the lead frame The upper end extends to the outside of the groove and is electrically connected to the pad. The light source module of claim 1, further comprising a metal layer at the bottom of the groove and bonded between the heat conductive material layer and the heat sink, wherein the metal layer and the heat conductive material layer The bonding ability is greater than the bonding ability of the heat sink to the heat conductive material layer. The light source module of claim 5, wherein the metal layer is made of copper, and the heat sink is made of aluminum. The light source module of claim 1, wherein the layer of thermally conductive material is formed on the bottom of the groove in a coating manner. The light source module of claim 7, wherein the material of the heat conductive material layer comprises tin. An embedded package structure is disposed in a recess, and a pad is disposed on an outer side of the recess, the embedded package structure includes: a light emitting component; and a lead frame disposed in the embedded package corresponding to the recess The structure is electrically connected to the light-emitting component, the recess is configured to receive the light-emitting component and the lead frame, and the upper end of the lead frame extends to the outside of the groove and is electrically connected to the pad; Encapsulating the light-emitting element and a portion of the lead frame, wherein a lower end of the lead frame extends into the sealant and is electrically connected to the light-emitting element; and a wafer holder is located at a bottom of the lead frame, and the light-emitting element is disposed on the light-emitting element On the wafer holder. The embedded package structure of claim 9, wherein the upper end of the lead frame extends from the side of the wafer holder in an L shape. Outside the sealant. The embedded package structure of claim 9, further comprising at least one wire, the light-emitting element being electrically connected to the lower end of the lead frame by the wire.