CN1228863C - Encapsulation molding method and finished product structure of light emitting diode - Google Patents

Abstract

A packaging forming method of Light Emitting Diode (LED) and finished product structure, make a platelike frame with conductive metal first, there are several forming areas on the frame, each forming area has a main slice and a separation arm; adhering an LED crystal grain on the top surface of each main sheet respectively, and molding a reflection ring respectively, wherein the crystal grain is positioned in the center of the reflection ring; then, a wire is drawn between the top surface of the crystal grain and the top surface of the separation arm by a wire bonding machine; then, forming a dome-shaped transparent packaging body on each forming area, wherein the packaging body encapsulates the crystal grain, the reflecting ring and the conducting wire, the bottom of the packaging body covers the main sheet and the separating arm, and the gap between the main sheet and the separating arm is filled to maintain the relative relation between the main sheet and the separating arm; finally, the LED is cut according to the size of the forming area of the plate-shaped frame to obtain a plurality of LEDs.

Description

Encapsulation molding method and finished product structure of light emitting diode

technical field

The present invention relates to optoelectronic semiconductors, in particular to an LED (Light-Emitting Diode; light-emitting diode) encapsulation molding method and finished product structure.

Background technique

The traditional "Lamp type" LED manufacturing method is to first make a frame with conductive metal. The frame includes a number of parallel and juxtaposed branches and a connecting strip that runs through the branches. A group of two is used as a positive terminal and a negative terminal of an LED. The front end of one of the terminals (usually the negative terminal) is formed into a cup and saucer shape (for reflecting light), and then an LED crystal is adhered by silver glue in the cup and saucer shape. One of the electrodes (n pole) of the grain is directly connected to the terminal, and the other electrode (p pole) of the grain is connected with the other end (positive terminal) with a wire bonding machine. A gold wire, and then form a dome-shaped (dome) package that wraps the crystal grain with epoxy resin at the front end of the two terminals by molding technology, and finally cut off the aforementioned connecting strips that are connected between the terminals, so That is, LEDs are produced one by one.

Although compared with other light-emitting devices (such as fluorescent lamps and incandescent lamps), the heat generated by LEDs is extremely low, but because LEDs emit bright light by passing current through semiconductors, their operating current generally ranges from tens to hundreds The milliamps are different, so the crystal grains will generate a certain degree of heat energy while emitting light, and this heat energy is often the biggest cause of damage to LEDs. Therefore, how to reduce heat energy generation or improve heat dissipation efficiency is the research and development improvement of LEDs today. One of the key points. For the above-mentioned commonly used LEDs, since the die is encapsulated in a package (epoxy resin) with poor thermal conductivity, and the contact surface between the die and the metal terminal is extremely small, and the terminal protrudes out of the package. Some are in the shape of thin rods, so the heat dissipation effect is extremely poor, and further improvement is needed.

Contents of the invention

The main purpose of the present invention is to provide an LED encapsulation molding method and a finished product structure. The LED produced by the method has a better heat dissipation effect and can prolong the service life of the LED.

In order to achieve the above-mentioned purpose, the encapsulation and molding method of LED provided by the present invention includes the following steps:

Step a: first make a plate-shaped frame with conductive metal, and there are several forming areas on the frame, and each forming area has a main piece and a partition arm, and the space between the separation arm and the main piece is not connected ;

Step b: Adhere an LED chip on the top surface of each main chip of the plate frame, so that an electrode on the bottom surface of the chip is electrically connected to the main chip; A reflective ring is formed on the sheet respectively, the reflective ring is opaque white plastic, and the inner peripheral surface forms an upward slope; the crystal grain is located in the center of the reflective ring;

Step c: Then use a wire bonding machine to draw a wire between another electrode on the top surface of the die and the top surface of the spacer arm;

Step d: Then, by molding technology, a package is molded on each of the molding areas of the plate frame with epoxy resin, the package encapsulates the chip, the reflective ring and the wire, and the package The bottom covers the main chip and the separation arm, and fills the gap between them to maintain the relative relationship between the main chip and the separation arm. In addition, the top of the package forms a dome shape;

Step e: Finally, cutting roughly according to the size of the forming area of the plate-shaped frame to obtain a number of the aforementioned LEDs.

Wherein in step b, the crystal grains are adhered first, and then the reflective ring is formed.

Wherein in step a, the molding areas on the plate-like frame are arranged neatly in a matrix, each of the molding areas is a hollowed-out rectangular window, and the central part of each of the molding areas has a rectangular main piece, and the main pieces are opposite to each other. The middle positions of the two sides are respectively connected with a connecting arm bridged to the edge of the forming area, and the middle position of the other side of the main sheet is connected with a protruding arm bridged to the edge of the forming area. The opposite side of the arm; in step b, a connecting strip is connected between two adjacent reflection rings in the same row, and the connecting strips are laid and glued on the connecting arm of the plate-like frame.

Wherein in step b, each of the crystal grains is a white light LED crystal grain.

Wherein in step b, the inner peripheral surface of each reflective ring faces upward at 45°.

The finished structure of the LED provided by the present invention includes:

a first terminal, generally in the form of a plate, made of conductive metal;

A second terminal, made of the same conductive metal as the first terminal, located on the side of the first terminal and separated from the first terminal by an appropriate distance;

An LED crystal grain, with its bottom surface flatly adhered to the top surface of the first terminal, so that an electrode on the bottom surface of the crystal grain is electrically connected to the first terminal;

a reflective ring formed on the top surface of the first terminal by molding technology, made of opaque white plastic, surrounding the periphery of the crystal grain, and the inner peripheral surface is an upward slope;

a wire connected between another electrode on the top surface of the die and the top surface of the second terminal; and

A package made of epoxy resin with high light transmittance and insulation, encapsulating the die, the reflective ring and the wire, and the bottom of the package covers the first terminal and the second terminal, and is embedded The relative relationship between the two terminals is maintained by keeping the space therebetween. In addition, the top of the package forms a dome shape.

Wherein the first terminal has a main piece, the crystal grain and the reflection ring are arranged on the top surface of the main piece, and the other side of the main piece opposite to the second terminal is connected with a protruding arm.

Wherein the grain is a white LED grain.

Wherein the inner peripheral surface of the reflective ring faces upward at 45°.

Description of drawings

Below in conjunction with accompanying drawing, give a preferred embodiment and describe the present invention in detail, wherein:

Fig. 1 is the flowchart of the LED encapsulation molding method of a preferred embodiment of the present invention;

Fig. 2 is the semi-finished product of the first step in a preferred embodiment of the present invention;

Fig. 3 is a sectional view along section line 3-3 in Fig. 2;

Fig. 4 is the semi-finished product of the second step in a preferred embodiment of the present invention;

Fig. 5 is a sectional view along section line 5-5 in Fig. 4;

Fig. 6 is the semi-finished product of the third step in a preferred embodiment of the present invention;

Fig. 7 is a sectional view along line 7-7 in Fig. 6;

Fig. 8 is the semi-finished product of the 4th step in a preferred embodiment of the present invention;

Fig. 9 is a sectional view along line 9-9 in Fig. 8;

Fig. 10 is the semi-finished product of the fifth step in a preferred embodiment of the present invention;

Figure 11 is a cross-sectional view along line 11-11 in Figure 10; and

Fig. 12 is a finished product of a single IED manufactured by a preferred embodiment of the present invention.

Detailed ways

A preferred embodiment of the present invention provides a packaging and molding method for "white LED" (note: the manufacturing method and finished product of the present invention are not limited to white LED), please refer to the flow chart of the method shown in Figure 1, as shown in the figure As shown, the method includes six major steps: "setting the plate frame", "sticking the die", "forming the reflective ring", "bonding", "forming the package" and "cutting"; with other drawings one by one described as follows:

Step 1: Please refer to Figure 2 and Figure 3, first make a plate-shaped frame (10) with conductive metal (usually copper), the frame (10) is roughly rectangular, and there are several molding areas that are hollow rectangular windows on the plate surface (11), the forming areas (11) are neatly arranged in a matrix, that is, the left and right sides and the upper and lower sides of the plate frame (10) form a frame to surround the forming areas ( 11) the longitudinal side strips (12) and the transverse side strips (13), and the forming areas (11) are separated by a number of (linked with the side strips (12) (13)) longitudinal spacers (14) and horizontal spacer (15) are divided; the hollow shapes inside each molding area (11) are exactly the same, that is: the central part of the molding area (11) has a rectangular main sheet (16), and the inside of the molding area (11) The upper and lower sides of the upper and lower sides each have a connecting arm (17) that simultaneously connects the main sheet (16) and the transverse spacer (15) (or transverse edge strip (13)) at the middle position, and the inner right side of the molding area (11) The side has a protruding arm (18) that simultaneously connects the main sheet (16) and the longitudinal spacer (14) (or longitudinal side strip (12)) at the middle position, and on the opposite side, that is, the forming area (11 ) inner left side, then form a spacer arm (19) that is only connected with the longitudinal spacer (14) (or longitudinal side bar (12)) in the middle position, but is separated from the main sheet (16) by an appropriate spacing.

Step 2: Please refer to Fig. 4 and Fig. 5, a white light LED crystal grain (20) is adhered to the top surface of each main piece (16) of the plate frame (10) respectively by silver glue (Note: LED crystal grain is a known technology , its epitaxial structure and light-emitting principle are not the key points of the present invention, and will not be described in detail; in addition, the "dic bon" technology is also a known technology), and each crystal grain (20) is flatly attached to the main chip (16) with the bottom surface ) top surface, an electrode on the bottom surface of the crystal grain (20) is directly attached to the metal main sheet (16) (through conductive silver glue) to form an electrical connection.

Step 3: Please refer to Fig. 6 and Fig. 7, by molding (injection molding) technology, plastic materials are used to form a reflector sticking on the top surface of each main piece (16) of the plate frame (10). Ring (30), each reflection ring (30) surrounds the periphery of crystal grain (20), its axial height is approximately equal to the height of crystal grain (20), and its inner peripheral surface (31) is an upward 45 ° slope ( Fig. 7) is used to refract the bright light emitted by the middle grain (20) upwards, for this reason, the reflective ring (30) itself is made of opaque white material; in addition, in order to facilitate the molding operation in production practice , the reflective rings (30) in the present embodiment have a vertical connection relationship, that is, a connecting strip (32) is connected between adjacent two reflecting rings (30) in the same column, and the connecting strips (32) Lay on the connecting arm (17) of the plate frame (10). It must be pointed out that, in fact, the two operations of "forming the reflective ring" and the aforementioned "die sticking" can be done in any order. In other words, the present invention can also mold the reflective ring (30) on the plate frame (10) first. ), and then stick a crystal grain (20) in each reflection ring (30).

Step 4: Please refer to Fig. 8 and Fig. 9, and then implicate a gold (99% Au) wires (40) (note: "wire bond" technology is also a known technology), so that another electrode on the top surface of the crystal grain (20) is electrically connected to the separator arm (19).

Step 5: Please refer to Fig. 10 and Fig. 11, and then use molding technology to form a package (50) on each molding area (11) of the plate frame (10) with epoxy resin (Epoxy) , each package (50) has a rectangular base (51) corresponding to the molding area (11), the base (51) not only fills the original vacant space inside the molding area (11), but also covers the board with a predetermined thickness on the top side The top surface of the frame (10) (note: the bases (51) of all packages (50) are connected together at present, so except for the main piece (16), the connecting arm (17), the convex Outrigger (18), spacer arm (19), also cover on the spacer (14) (15) of plate frame (10)), in the present embodiment, base (51) exceeds plate frame (10) The height of the top surface is approximately equal to the height of the reflective ring (30); each package (50) is integrally connected with a hemispherical raised portion (52) above the rectangular base (51), except for the overmolding The crystal grain (20), reflective ring (30) and wire (40) on the area (11) are used to maintain the mechanical structure of the crystal grain (20) and prevent moisture intrusion, and the package body (50) itself has a light transmittance Excellent transparent material, so that the light emitted by the crystal grain (20) can be refracted to the spherical surface at the top of the protrusion (52) through the inner peripheral surface (31) of the refraction ring (30); in addition, the package (50) has an insulating Effect.

Step 6: Finally, cut according to the size (or slightly smaller) of the molding area (11) of the plate-shaped frame (10) (meaning the side bars (12) (13) and spacers (14) of the frame (10) ( 15) are all planted), and obtain some LEDs (60) as shown in Figure 12.

As shown in Figures 11 and 12, the IED (60) obtained according to the above-mentioned method comprises respectively in structure: a first terminal (70), which is connected to the main sheet (16) by the aforementioned main sheet (16) The protruding arm (18) on the right side is composed of two connecting arms (17) connected to the upper and lower sides of the main sheet (16) respectively, and the material is conductive metal; a second terminal (80), namely the aforementioned The separation arm (19) is located on the left side of the first terminal (70) and is separated from the first terminal by an appropriate distance, and the material is the same conductive metal as the first terminal (70); an LED crystal grain (20), with Its bottom surface is flatly adhered to the top surface of the main sheet (16) of the first terminal (70), so that an electrode on the bottom surface of the crystal grain (20) is electrically connected to the first terminal (70); a reflective ring (30), Formed on the top surface of the main piece (16) of the first terminal (70) by molding technology, the material is opaque white plastic, surrounds the periphery of the crystal grain (20), and the inner peripheral surface is an upward slope; A wire (40) connected between another electrode on the top surface of the crystal grain (20) and the top surface of the second terminal (80); a package (50) made of epoxy with high light transmittance and insulation Resin encapsulates the die (20), the reflection ring (30) and the wire (40), and the bottom of the package (50) (ie the base (51)) covers the first terminal (70) and the second terminal (80) the top surface, and fill the space therebetween to maintain the relative relationship between the two terminals (70) (80). In addition, the top of the package (50) forms a dome shape (that is, the raised portion (52)). When in use, use the two terminals (70) (80) to couple the positive and negative poles of the power supply (Note: The polarity distinction is different according to the type of the crystal (20). Generally speaking, the first terminal (70) As an anode, and the second terminal (80) as a cathode), the current passes through the LED grain (20) to make the grain emit white light, which is refracted to the packaging body through the inner peripheral surface (31) of the refraction ring (30) (50) spherical surface at the top.

It can be seen from the above description that the LED (60) produced by the method of the present invention has a relatively large contact area because the LED grain (20) is flatly attached to the top surface of the metal main sheet (16). The main chip (16) (more precisely, the first terminal (70)) itself is also a large-area plate, and its bottom surface is completely exposed to the outside. Therefore, when the LED (60) is in use, the crystal grain (20) The generated heat can be quickly conducted to the first terminal (70), and then dissipated to the outside from the bottom surface of the terminal (70), so that the LED (60) produced by the present invention has a good heat dissipation effect and a long service life. life.

Claims (9)

1, a kind of encapsulated moulding method of light-emitting diode includes the following step:

Step a: make a plate-shaped frame with conducting metal, have some shaping areas on this framework, respectively have a main leaf and a divider arms in this shaping area, have the space between this divider arms and this main leaf and be not connected;

Step b: the adhesive LED crystal particle of respectively this main leaf end face difference at this plate-shaped frame makes an electrode of this crystal grain bottom surface and this main leaf form electric connection; And, respectively distinguishing moulding one tore of reflection on this main leaf by molded technology, this tore of reflection is lighttight white plastic, and inner peripheral surface forms inclined-plane up; This crystal grain position is in these tore of reflection central authorities;

Step c: between another electrode of this crystal grain end face and this divider arms end face, involve a lead with wire bonder;

Steps d: by molded technology, with epoxy resin moulding one packaging body on respectively this shaping area of this plate-shaped frame, this packaging body envelope is wrapped up in this crystal grain, this tore of reflection and this lead, and package bottom covers this main leaf and this divider arms, and pointing space and keep the relativeness of main leaf and divider arms therebetween, in addition, cheese is formed on the packaging body top;

Step e: roughly the shaping area size according to this plate-shaped frame cuts, and obtains some aforementioned light-emitting diodes.

2, according to the described encapsulated moulding method of claim 1, it is characterized in that, wherein in step b, adhesive this crystal grain earlier, this tore of reflection of reshaping.

3, according to the described encapsulated moulding method of claim 1, it is characterized in that, wherein in step a, this shaping area on this plate-shaped frame is rectangular proper alignment, respectively this shaping area is hollow out square window, respectively the central part of this shaping area has a rectangle main leaf, this main leaf wherein relatively the dual side-edge centre position respectively link an armite that bridges to the shaping area rim, another side centre position binding one of this main leaf bridges to the arm that protrudes out of shaping area rim, and aforementioned divider arms position is protruding out another relative side of arm with this; In step b, all linking between adjacent two these tores of reflection of same array has a linking strip, and this linking strip shop sticks on the armite of this plate-shaped frame.

According to the described encapsulated moulding method of claim 1, it is characterized in that 4, wherein in step b, respectively this crystal grain is white light LEDs crystal grain.

5, according to the described encapsulated moulding method of claim 1, it is characterized in that, wherein in step b, respectively the inner peripheral surface of this tore of reflection be 45 ° up.

6, a kind of finished product structure of light-emitting diode includes:

One the first terminal generally is en plaque, and material is a conducting metal;

One second terminal, material are the conducting metal that is same as this first terminal, the position this first terminal side and with the first terminal suitable spacing of being separated by;

One LED crystal particle, smooth adhesive with its bottom surface in this first terminal end face, make an electrode of crystal grain bottom surface and this first terminal form electric connection;

One tore of reflection takes shape in this first terminal end face with molding technology, and material is lighttight white plastic, be surrounded on this crystal grain periphery, and inner peripheral surface is inclined-plane up;

One lead is connected between another electrode and this second terminal end face of this crystal grain end face; And

One packaging body, material is the epoxy resin that light transmittance is high and insulate, envelope is wrapped up in this crystal grain, this tore of reflection and this lead, and this package bottom covers this first terminal and this second terminal, and pointing space and keep the relativeness of this two-terminal therebetween, in addition, cheese is formed on this packaging body top.

7, according to the described finished product structure of claim 6, it is characterized in that wherein this first terminal has a main leaf, this crystal grain and this tore of reflection are located at this main leaf end face, and this main leaf another side binding one of this second terminal relatively protrudes out arm.

According to the described finished product structure of claim 6, it is characterized in that 8, wherein this crystal grain is white light emitting diode crystal grain.

9, according to the described finished product structure of claim 6, it is characterized in that, wherein the inner peripheral surface of this tore of reflection be 45 ° up.

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