JP2006179541A - Lead frame for power led and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead frame for power LED in which assembling work of components is not required, the occurrence rate of defective products is lower and manufacturing cost is relatively low, and to provide a manufacturing process of a lead frame for power LED in which assembling work of components is not required, the occurrence rate of defective products is low, manufacturing cost is relatively low and processing speed is high. <P>SOLUTION: A lead frame for power LED in which a heat sink portion 1 and a lead portion 3 at least on one side are made integrally of the same metal material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power LED lead frame which is a high power consumption light emitting diode and a method for manufacturing the same.

  Since power LEDs have high power consumption and a large amount of heat generation, high electrical conductivity and high heat dissipation are required, and therefore metal lead frames are used as power LED lead frames.

  In the conventional power LED lead frame, the heat sink portion and the lead portion are completely different parts. 9 and 10 are schematic views of a conventional lead frame for power LED, (a) is a plan view thereof, and (b) is a front view thereof.

  A semiconductor body (LED) chip 4 is die-bonded and bonded to the heat sink portion 1 after a resin body is attached and molded to a metal lead frame by injection molding. Therefore, the heat sink portion 1 is designed to have a large plate thickness using copper or copper alloy having high thermal conductivity in order to easily release heat generated from the semiconductor chip.

  On the other hand, since the lead portions 2 and 3 do not need to release heat, and workability such as conductivity, strength, punching, and bending is required, various copper alloys, iron alloys and their plating materials are used. The plate thickness is also designed to be thin.

  The lead portions 2 and 3 are successively subjected to processing such as punching, bending, and tapping a long metal material using a transfer press. That is, a large number of lead portions 2 and 3 are connected to connection portions and feed holes (not shown), are long and can be automatically fed.

  On the other hand, the heat sink portion 1 is formed as individual parts by forming the upper surface 11, the inner surface 12, the lower surface 13, the bottom surface 14, and the outer surface 15 by processing such as coining and drawing. A rectangular protrusion is formed on the bottom surface 14 in order to improve heat dissipation and mounting ease.

  In the conventional power LED lead frame shown in FIG. 9, the heat sink portion 1 and the lead portions 2 and 3 are separated, but in the conventional power LED lead frame shown in FIG. Are caulked and joined by caulking 8. For caulking, a cylindrical pin is formed at a predetermined position on the upper surface 11 of the heat sink part 1, and on the other hand, a circular through hole is formed at a predetermined position on the lead part 3. After passing through, pin the head of the pin and crush it.

  As another conventional technique, after the heat sink part and the lead part are set at predetermined positions, spot welding or the like is performed to join them.

  11 and 12 are schematic views showing a state in which a resin body portion is formed on a conventional power LED lead frame, (a) is a plan view thereof, and (b) is a front view thereof.

  In FIG. 11, in a state where the heat sink part 1 and the lead parts 2 and 3 are not joined, the mold is closed after being placed at a predetermined position in the mold of the injection molding machine or the mold, and the heat-melting resin is made of gold. After being pressure-injected into the mold, it is cooled and solidified, and the resin body 6 is attached and formed on the metal lead frame.

  On the other hand, in FIG. 12, the heat sink portion 1 and the lead portion 3 are crimped and joined, but are not joined to the lead portion 2, and a predetermined position in the mold or mold of the injection molding machine. 9 is different from the prior art shown in FIGS. 9 and 11 in other points, but is almost the same in other points.

  In any of the conventional techniques, the shape of the resin body 6 is the same, but it is a substantially rectangular parallelepiped surrounded by the upper surface 61, the side surfaces 65, 66, 67, 68, and the bottom surface 69, and the upper surface 61 has a circular upper edge. 60 is recessed toward the lower edge 63 of the rhombus with rounded corners, and an inclined surface 62 is formed. From the lower edge 63 toward the boundary between the lead portions 2 and 3 and the upper surface of the heat sink portion 1, the surface is further recessed and inclined. Is formed. A positioning mark 64 is provided at one corner of the upper surface 61.

  However, in the prior art, since the heat sink part and the lead part are separate parts, if there is any error in the dimensional accuracy or alignment of each part, it becomes a defective product, so the defect rate is high and high precision. Alignment is necessary and the cost is high.

  Moreover, even if an automatic supply set machine for the heat sink part is used, the processing speed is significantly slower than the processing speed in the other steps, which leads to a decrease in the manufacturing speed as a whole.

  Accordingly, an object of the present invention is to provide a lead frame for a power LED that does not require assembly of parts, has a low defective product generation rate, and is relatively low in cost, and does not require assembly of components, and has a low defective product generation rate. A method of manufacturing a power LED lead frame that is relatively low cost and has a high processing speed is provided.

  The above object is achieved by the power LED lead frame according to claim 1, that is, the heat LED lead frame, wherein the heat sink part and at least one lead part are integrally manufactured of the same metal material. Achieved.

  Further, the above object is to provide a power LED lead frame manufacturing method according to claim 2, that is, a length in which a thickness portion having a thickness ratio of 4: 1 to 6: 1 and a normal portion are arranged in the longitudinal direction. It is also achieved by a power LED lead frame manufacturing method in which an irregularly shaped metal material is passed through a transfer press and an injection molding machine to perform punching, bending, and resin molding of the metal material.

  In the power LED lead frame according to the present invention, since the heat sink part and at least one lead part are integrally manufactured from the same metal material, there is no need to combine and join the heat sink part and the lead part. Thus, an effect that no combination failure or bonding failure occurs is obtained.

  Moreover, the manufacturing method of the lead frame for power LED according to the present invention performs the punching process, bending process and resin molding process of the metal material by passing the long irregular metal material through a transfer press and an injection molding machine. In addition to the above effect, the metal lead frame can be passed through at a high processing speed in the pressing process and the insert molding process, and the processing line speed can be kept high.

  Hereinafter, lead frames for power LEDs according to various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 8 is a perspective view of a long irregular metal cut material used for manufacturing the power LED lead frame of the embodiment. It is an irregularly shaped long plate material having a length L and a width (W1 + W2 + W3 + W4 + W5), and the material is oxygen-free copper, oxygen-free copper, phosphor bronze or the like. The length L is 400-1800 mm. The thick portions 72 and 74 and the thin portions 71, 73, and 75 are arranged in the length direction. The thicknesses t2 and t4 of the thick portions 72 and 74 are equal, and the thicknesses t1, t3, and t5 of the thin portions 71, 73, and 75 are equal, and t1: t2 = 1: 4 to 1: 6.

  A groove roll rolling method and a cutting method are preferable as a method for producing a long irregular cut material, but an etching removal method, an extrusion method, and a drawing method are also conceivable.

  The long irregular shaped cut material shown in the figure has two rows of thick portions, but may be one row or three rows.

In the thin portions 71 and 75, lead portions are formed by a press process in a later step, and feed holes for sequentially feeding the long irregularly shaped cut materials are also formed.
First embodiment

  1A and 1B are schematic views of a power LED lead frame according to the first embodiment. FIG. 1A is a plan view thereof, and FIG. 1B is a front view thereof.

  The heat sink part 1 is formed by punching a thick part of a deformed material and coining, and the lead parts 2 and 3 are formed by punching a thin part of a deformed material. The heat sink part 1 and the lead part 3 Is directly continuous and is manufactured in one piece. The lead portion 2 is also indirectly connected to the heat sink portion 1 by a fishing lead or a frame (not shown), but the tip surface 22 of the lead portion 2 and the outer surface 15 of the heat sink portion 1 are separated from each other. The heat sink portion 1 is formed with a truncated cone-shaped recess composed of a lower surface 13 and an inner surface 12 by pressing. The semiconductor chip 4 is bonded to the lower surface 13 in a subsequent process. Since the recess is provided in the heat sink portion 1, the position of the upper surface of the semiconductor chip 4 and the position of the upper surface 21 of the lead portions 2 and 3 are almost the same level, so the length of the Au wire 5 for wire bonding is shortened. Can save cost.

  The planar shape of the heat sink portion is a rectangle in the first embodiment.

  2A and 2B are schematic views of the power LED lead frame of the first embodiment in which a resin body portion is formed. FIG. 2A is a plan view thereof, and FIG. 2B is a front view thereof.

The resin body 6 is a substantially rectangular parallelepiped surrounded by an upper surface 61, side surfaces 65, 66, 67, 68 and a bottom surface 69. The upper surface 61 is recessed from the upper edge 60 of the circle toward the lower edge 63 of the rhombus with rounded corners, and an inclined surface 62 is formed from the lower edge 63 to the upper surfaces of the lead portions 2 and 3 and the heat sink portion 1. Towards the border, a further depression and inclined surface are formed. A positioning mark 64 is provided at one corner of the upper surface 61.
Second embodiment

  3A and 3B are schematic views of a power LED lead frame according to a second embodiment in which a resin body portion is formed. FIG. 3A is a plan view thereof, and FIG. 3B is a front view thereof.

The difference from the first embodiment is that the upper surface 11 of the heat sink portion 1 is flat and no depression is formed. Therefore, the thickness of the heat sink part 1 is almost equal to the thickness of the thick part of the material, and the heat dissipation performance is excellent. On the other hand, when the semiconductor chip 4 is bonded to the upper surface 11 of the heat sink portion 1, the position of the upper surface of the semiconductor chip 4 becomes higher than the position of the upper surface 21 of the lead portion 2 by the height of the semiconductor chip 4. Therefore, the Au wire to be wire-bonded becomes long and the cost becomes high.
Third embodiment

  FIG. 4 is an explanatory view showing various shapes of the lower edge of the resin body portion.

  (A) is a shape in which two small semicircles are added to the great circle 180 degrees apart around the center of the great circle. (B) is a large circle. (C) is a shape in which a small semicircle is added to each pair of opposite corners of the rhombus. (D) is a rectangular shape with four rounded corners. (E) is a shape obtained by adding an angle of about 120 ° to a great circle at a position 180 ° away from the center of the great circle. (F) is a shape obtained by adding a square to a great circle at a position 180 ° away from the center of the great circle. (G) is a shape in which two ellipses are combined such that their long axes are orthogonal to each other and have a common center. (H) is a shape in which ellipses close to two circles are combined such that their long axes are orthogonal and the centers are common.

If the shape of the lower edge of the resin body part is changed, the way in which the light generated from the LED spreads is different, and the light source can have various impressions and atmospheres.
Fourth embodiment

  5A and 5B are schematic views of a power LED lead frame according to the fourth embodiment. FIG. 5A is a plan view thereof, and FIG. 5B is a front view thereof.

The heat sink portion 1 is formed by punching and coining a thick portion of an irregularly shaped material. However, the planar shape is different from the first embodiment in that it is a quadrangle with rounded corners, and is substantially the same in other points. is there.
Fifth embodiment

  6A and 6B are schematic views of a power LED lead frame according to a fifth embodiment. FIG. 6A is a plan view thereof, and FIG. 6B is a front view thereof.

The heat sink part 1 is formed by punching and coining a thick part of an irregularly shaped material, but the planar shape is a shape obtained by cutting a circle by two parallel straight lines, and is a combination of an arc and a straight line. Unlike the first embodiment, the other points are almost the same.
Sixth embodiment

  7A and 7B are schematic views of a power LED lead frame according to the sixth embodiment. FIG. 7A is a plan view thereof, and FIG. 7B is a front view thereof.

  The heat sink portion 1 is formed by punching and coining a thick portion of an irregularly shaped material, but the planar shape is the first in that the rectangular corner is cut by a straight line that forms an angle of 45 ° with respect to the side. Unlike the embodiment, the other points are almost the same.

It is the schematic of the lead frame for power LEDs of 1st Embodiment, (a) is the top view, (b) is the front view. It is the schematic of the lead frame for power LEDs of 1st Embodiment which formed the resin-made body parts, (a) is the top view, (b) is the front view. It is the schematic of the lead frame for power LEDs of 2nd Embodiment which formed the resin-made body part, (a) is the top view, (b) is the front view. It is explanatory drawing which shows the various shapes of the lower edge of a resin-made body part. It is the schematic of the lead frame for power LEDs of 4th Embodiment, (a) is the top view, (b) is the front view. It is the schematic of the lead frame for power LEDs of 5th Embodiment, (a) is the top view, (b) is the front view. It is the schematic of the lead frame for power LEDs of 6th Embodiment, (a) is the top view, (b) is the front view. It is a perspective view of the long irregular-shaped metal cutting material used for manufacture of the lead frame for power LEDs of embodiment. It is the schematic of the conventional lead frame for power LEDs, (a) is the top view, (b) is the front view. It is the schematic of the conventional lead frame for power LEDs, (a) is the top view, (b) is the front view. It is the schematic which shows the state which formed the resin-made body part in the conventional lead frame for power LEDs, (a) is the top view, (b) is the front view. It is the schematic which shows the state which formed the resin-made body part in the conventional lead frame for power LEDs, (a) is the top view, (b) is the front view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat sink part 11 Upper surface 12 Inner side surface 13 Lower surface 14 Bottom surface 15 Outer side surface 2 Lead part 21 Upper surface 22 Front end surface 3 Lead part 4 Semiconductor (LED) chip 5 Au wire 6 Resin body part 60 Upper edge 61 Upper surface 62 Inclined surface 63 Lower edge 64 Positioning mark 65 Side surface 66 Side surface 67 Side surface 68 Side surface 69 Bottom surface 71 Thin portion 72 Thick portion 73 Thin portion 74 Thick portion 75 Thin portion 8 Caulking

Claims (4)

A power LED lead frame, wherein the heat sink part and at least one lead part are integrally made of the same metal material. Punching and bending of metal material through a transfer press and an injection molding machine, a long irregular metal material with a thickness ratio of 4: 1 to 6: 1 and a normal part aligned in the longitudinal direction. A method for manufacturing a lead frame for power LEDs that performs processing and resin molding. The method for producing a lead frame for a power LED according to claim 2, wherein the long irregular metal material is a coil material rolled using a grooved rolling roller. The method for manufacturing a lead frame for a power LED according to claim 2, wherein the long irregular metal material is a cut material obtained by partially cutting a long plate material.

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