JP3880115B2 - Surface mount type light emitting diode - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mounting structure for a surface-mounted light emitting diode.
[0002]
[Prior art]
The structure and manufacturing method of a surface-mounted light-emitting diode having an anode and a cathode electrode plate on a surface parallel to the PN junction of a light-emitting diode and having a side surface coated with an insulator is disclosed in JP-A-6-275684, JP-A-6-326365, JP-A-7-283439, etc., all of which are processed and manufactured in the state of a semiconductor wafer, each of which constitutes an electrode part, and an insulating core is provided on a side part. It is devised so that it is subjected to dicing and divided into dicing and used for surface mount type parts (SMD). Among them, JP-A-6-326365 forms a coating layer with a thin insulating material on the wafer element cut surface, and there is a problem in handling the same as a normal component chip in mechanical strength. Since Kaihei 7-283439 has a structure in which the wafer portion on the side surface other than the PN junction is exposed, there is a problem in handling the same as a normal part. Japanese Patent Laid-Open No. 6-275684 discloses a method for molding an insulating material layer in a groove of a mesa structure, but it requires a special structure called a mesa structure. Further, in any of the above-mentioned inventions, no special consideration is given to a structure that enables the electrode plate to be automatically identified and processed at the same level as a chip component such as a normal resistor or capacitor.
[0003]
The present inventor's own patent application already filed, Japanese Patent Application No. 8-308674 relates to a method of manufacturing a surface-mounted semiconductor device including a light-emitting diode and a surface-mounted light-emitting diode formed thereby. FIG. 5 is a perspective view showing the structure of a surface-mounted light emitting diode manufactured by this manufacturing method.
In this manufacturing method, a light emitting diode element wafer adhered on a dicing sheet is subjected to full dicing to a desired chip size in the vertical, horizontal, and respective light emitting diode element chips, and this full dicing is performed. The dicing sheet with each semiconductor element chip attached is expanded to a desired size, and the cathode side of each light emitting diode element chip on the expanded dicing sheet is bonded to the cathode electrode plate. After curing, the dicing sheet was peeled off, and the anode side of each of the peeled light emitting diode element chips was bonded and cured in the same manner to the anode electrode plate, and then between the light emitting diode element chips. Translucent resin is filled and cured, and the anode and cathode electrode plates and the filled translucent resin are sliced vertically and horizontally and separated into individual light emitting diodes. As shown in FIG. 5, the structure of the light emitting diode formed by this manufacturing method is such that the gap portion sandwiched between the two electrode plates 2 and 5 of the light emitting diode element chip 1 is formed by a translucent resin 6. It had a robust structure that filled and molded to thickness. As shown in FIG. 5, in the above Japanese Patent Application No. 8-308674, the thickness of the translucent resin 6 can be adjusted to a desired size, thereby eliminating the weak point of the above-mentioned prior art called mechanical strength. Although it was a chip-size package component, it had a robust structure and pursued the possibility of handling like chip components such as resistors and capacitors, but still left some problems in polarity discrimination etc. It was.
[0004]
[Problems to be solved by the invention]
The present invention further advances the prior art disclosed in the above-mentioned Japanese Patent Application Laid-Open Nos. 6-275684, 6-326365 and 7-283439, and the invention of the above-mentioned Japanese Patent Application No. 8-308674, which is an ultra-small chip. By making the surface-mount type light-emitting diode of the size package (CSP) so that the polarity can be discriminated, it can be handled as easily as chip components such as ordinary resistors and capacitors, preventing reverse mounting and miswiring. It is intended to enable automatic assembly, measurement and the like by being able to convey and supply by automatic supply means such as a part feeder.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the surface-mounted light-emitting diode of the present invention is a surface-mounted light-emitting diode having an anode and a cathode electrode plate on a plane parallel to the PN junction portion of the light-emitting diode element chip. In the diode, the anode electrode plate and the cathode electrode plate are formed of metal plates having different thicknesses, and the anode electrode plate and the cathode electrode plate have at least a thin side. A concave mark for identifying the polarity of the electrode plate is formed on the metal plate.
Further, in the surface-mount type light emitting diode having an anode and a cathode electrode plate on a surface parallel to the PN junction portion of the light emitting diode element chip, the anode electrode plate and the cathode electrode are provided. The plate is formed of a metal plate having a different thickness, and at least one of the anode electrode plate and the cathode electrode plate is a metal plate formed into a concave shape, and a convex dowel is formed inside the metal plate. The concave mark is formed on a metal plate having a smaller thickness among the metal plates having different thicknesses, and the convex dowel is formed on a side surface portion of the light emitting diode element chip on the PN junction side. It is connected to a part of the center.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
1 to 4 are explanatory views for explaining the structure of a surface-mounted light emitting diode according to the present invention. FIG. 1 is a front view, FIG. 2 is a perspective view seen from the anode side, and FIG. FIG. 4 is a perspective view as seen from the cathode side, and FIG.
As can be seen from the figure, the light-emitting diode element chip 1 exists in the middle, and anode electrodes are provided at both end portions 1b (anod electrode side) and 1c (cathode electrode side) parallel to the PN junction 1a. 2 and the cathode electrode 5 are bonded and fixed so as to sandwich the conductive sheet or silver paste 3 and 4 therebetween, the anode electrode plate 2, the cathode electrode plate 5 and The gap formed by the light-emitting diode element chip 1 is filled and molded to a desired thickness by the translucent epoxy resin 6, and the side surface of the light-emitting diode element chip 1 has both electrode plates 2, 5 and It is mechanically protected from the outside by the translucent epoxy resin 6 and has a solid block structure which is a rectangular parallelepiped as a whole.
The anode electrode plate 2 is made of copper or a copper alloy plate, and is formed into a concave portion 2a on the outer side and a convex portion 2b (dubbed portion) on the inner side by half punching press processing. The cathode electrode plate 5 is also made of copper or a copper alloy, and a minus mark (−) 5a is formed on the outside by press working. Then, the dowel portion 2a of the anode electrode plate and the anode electrode side 1b of the light-emitting diode element chip 1 and the silver paste or the like so as to substantially coincide with the center line CL of the light-emitting diode element chip 1. The side 5b of the cathode electrode plate 5 which is bonded by the conductive sheet 3 and does not have a negative mark is attached to the cathode of the light emitting diode element chip 1 by the silver paste or the conductive sheet 4. It is bonded to the electrode side 1c. As described above, the gap formed by the light-emitting diode element chip 1 and the two electrode plates 2 and 5 is filled with the translucent epoxy resin 6, and the light-emitting diode element chip 1 has the both electrode plates 2. 5 and the translucent epoxy resin 6 are protected from the outside and are generally symmetrical with respect to the center line CL perpendicular to the PN junction 1a as a whole. The four side surfaces have the same rectangular shape. The surface of each electrode plate is coated with solder or gold plating 7 or 8 so that it can be surface-mounted.
In the case of this embodiment, the anode electrode 2 is a 500 micron × 500 micron square with a thickness of 200 microns, and the cathode electrode 5 is a 500 micron × 500 micron square with a thickness of 300 microns. The cross section of the photo-epoxy resin 6 mold is 500 μm × 500 μm square, the same as the two electrode plates 2, 5, and all sides are rectangular of 500 μm × 400 μm. The light emitting diode as a whole is 500 μm. A rectangle of × 900 microns. It goes without saying that these numerical values are merely examples of this embodiment and the present invention is not limited thereto. In this embodiment, the anode electrode plate is formed in a concave shape. This indicates that the electrode plate formed in the concave shape is an anode (type) and a positive pole. In short, since the concave shape is for distinguishing one from the other, the cathode electrode plate may be formed in a concave shape. In this case, the portion formed in a concave shape is a cathode (type) and represents a negative pole. By forming such a concave shape, the polarity can be displayed even if there is no + -mark display. In this embodiment, the cathode electrode plate is positively minus-marked (-) to display the polarity. The cathode electrode plate may be formed in a concave shape, and a positive mark (+) may be positively provided only on the anode electrode plate. Except for the identification processing of these electrode plates, the molding method using the translucent epoxy resin 6 is basically the same as that described in Japanese Patent Application No. 8-308674. The operation of the above structure will be described below.
[0007]
Since the surface of the anode electrode plate 2 is formed of a metal plate formed into a concave shape 2a, the shape can be distinguished from the cathode electrode plate 5 at the same time, and at the same time the polarity of the electrode can be discriminated. Can be prevented.
In this embodiment, the anode electrode plate 2 has a thickness of 200 microns, and the cathode electrode plate 5 has a thickness of 300 microns, so that it can be distinguished from the cathode electrode in shape, and at the same time, the polarity of the electrode It can be discriminated, and similarly reverse mounting and miswiring can be prevented.
Since a minus mark (-) is formed on the cathode electrode, the discrimination function can be further increased visually. As a result, shape discrimination and electrode discrimination became extremely easy, and assembly work and wiring work were remarkably improved.
Further, it is determined whether or not the half-cut dowel portion 2b (convex portion) having a size equal to or smaller than the chip size of the anode electrode plate 2 substantially coincides with the center line CL of the light emitting diode element chip. Since it can be seen through the surface of the translucent epoxy resin 6, it is possible to easily determine whether or not the light emitting diode element chip 1 is misaligned. Judgment and assembly quality stability can be obtained.
In addition to these electrode identifiable structures, both sides have the same rectangular shape of 500 microns × 900 microns, so that any of the four surfaces can be mounted and fixed, and the characteristics of the light emitting diode And is not affected by reliability.
Further, even if the light emission characteristics are measured, it is the same regardless of which of the four surfaces, so that it is not necessary to select a surface, and the setting operation for measurement is facilitated.
Similarly, since both the above-described structure and side surfaces of the electrode plate have the same rectangular shape, it can be easily aligned and transported by a part feeder or the like as usual parts. Assembly work has become easier.
For the same reason, the direction of application of the measurement voltage and the direction of measurement of the light emission characteristics are also determined, so that the measurement selection operation can be performed automatically and continuously in the same manner as normal chip components such as resistors and capacitors.
In the above, the optimum embodiment of the present invention has been described mainly as a development form of Japanese Patent Application No. 8-308674. However, in so-called chip size package parts, a recess is formed in the electrode plate, and the thickness of the electrode plate is varied. Of course, the technique of forming a polar mark on the electrode plate can be effectively applied to any side-coating or molding light-emitting diode as long as it is of a type having both electrode plates. It is.
[0008]
【The invention's effect】
As is apparent from the above description, the surface-mounted light-emitting diode of the present invention has a shape that enables polarity identification in itself even though it is an ultra-small chip-size package component. Therefore, it is easy to handle. For both the manufacturing manufacturer and the set manufacturer, the same parts as resistors, capacitors, etc., as well as automatic transport and supply by parts feeders, etc. The automatic assembly measurement and sorting can be easily performed, and thus can be used without the need to change the conventional assembly line, and the effect on the improvement of yield and productivity is enormous.
[Brief description of the drawings]
FIG. 1 is a front view of a surface-mounted light-emitting diode according to the present invention.
FIG. 2 is a perspective view of a surface-mounted light emitting diode according to the present invention as viewed from the anode side.
FIG. 3 is a perspective view of a surface-mounted light-emitting diode according to the present invention as viewed from the cathode side.
4 is a cross-sectional view taken along the line IV-IV in FIG. 2;
FIG. 5 is a perspective view showing the structure of a surface-mounted light emitting diode manufactured by the manufacturing method of Japanese Patent Application No. 8-308674.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Light emitting diode element chip 1a PN junction 1b The anode electrode side 1c of the light emitting diode element chip 2 The cathode electrode side 2 of the light emitting diode element chip 2 Anode electrode plate 2a Recessed part 2b Dowel part (convex) Section)
3 Silver paste or conductive sheet 4 Silver paste or conductive sheet 5 Cathode electrode plate 5a Minus mark 5b Side where no minus mark exists 6 Translucent epoxy resin 7 Solder or gold plating 8 Solder or gold plating

Claims (2)

In a surface mount type light emitting diode having an anode and a cathode electrode plate on a surface parallel to a PN junction of a light emitting diode element chip,
The anode electrode plate and the cathode electrode plate are formed of metal plates having different thicknesses,
A surface-mount type light emitting diode characterized in that a concave mark for identifying the polarity of the electrode plate is formed on at least a metal plate on the side of the anode electrode plate and the cathode electrode plate which are thin. . In a surface mount type light emitting diode having an anode and a cathode electrode plate on a surface parallel to a PN junction of a light emitting diode element chip,
The anode electrode plate and the cathode electrode plate are formed of metal plates having different thicknesses,
The outer side of at least one of the anode electrode plate and the cathode electrode plate is made of a metal plate formed into a concave shape, and a convex dowel is formed on the inner side,
The concave mark is formed on a thin metal plate among the metal plates having different thicknesses, and the convex dowel is formed at the center of the side surface of the light emitting diode element chip on the PN junction side. A surface-mounted light-emitting diode characterized by being connected to a part of

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