JP4003866B2 - Surface mount type light emitting diode and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface-mounted light emitting diode (hereinafter abbreviated as LED) and a method for manufacturing the same.
[0002]
[Prior art]
The LED forms a PN junction on a III-V group compound semiconductor wafer such as GaP or GaN, and emits visible or near-infrared light through a forward current. Widely applied to control and the like. However, such conventional LEDs have only a limited color tone. Therefore, in order to obtain a desired color light source, there has been an attempt to include a fluorescent substance or a colorant in a sealing resin such as an epoxy resin or a silicone resin in a GaN-based LED. An example of such a conventional LED will be described with reference to the drawings.
[0003]
FIG. 5 is a longitudinal sectional view of a conventional LED 50. 51 is a wiring board made of BT resin resin or the like coated with a double-sided copper foil. A plating resist is laminated on the double-sided copper foil portion of the wiring board 51, exposed and developed to form a wiring pattern, and gold plating or the like is further formed thereon. Surface treatment. 52 is one electrode pattern which is a wiring pattern extending from the upper surface electrode 52a via the side electrode 52b to the lower surface electrode 52c, and 53 similarly reaches from the upper surface electrode 53a via the side electrode 53b to the lower surface electrode 53c. It is the other electrode pattern.
[0004]
54 is a die pattern formed on the wiring substrate 51. Reference numeral 55 denotes a GaN-based blue LED element in which one electrode is die-bonded to the upper surface electrode 52a with silver paste. Reference numeral 56 denotes a wire made of Au wire or the like, and by the wire 56, one electrode of the LED element 55 is wire-bonded to the upper surface electrode 52a and the other electrode is bonded to the upper surface electrode 53a. 57 is a translucent epoxy resin or the like that seals the LED element 55, the connection portion of the LED element 55, the wire 56, etc. and seals the LED element 55 to make the light emission effective. Is a sealing resin. The sealing resin 57 contains either one or both of a fluorescent substance (YAG phosphor) and a colorant in advance.
[0005]
If only the fluorescent material is contained in the sealing resin 57, when the LED 50 is caused to emit light, the blue light emitted from the LED element 55 and hitting the fluorescent material changes to yellow and is emitted to the fluorescent material. The light that did not hit is emitted in blue. Therefore, the emitted light is a mixture of yellow and blue and becomes white light. If only the colorant is contained in the sealing resin 57, the emitted light has a color tone in which the blue color of the LED 50 and the color tone of the colorant are mixed. If the sealing resin 57 contains a fluorescent substance and a colorant, a desired emission color can be obtained by mixing the white light with the light of the color tone of the colorant.
[0006]
[Problems to be solved by the invention]
However, in such a conventional LED, since the specific gravity of the fluorescent material is larger than that of the sealing resin, the fluorescent material is precipitated in the process of curing the resin in the curing furnace after being mixed in the resin, and uniform in the resin. Can not diffuse. Further, it is difficult to finely adjust the amount of the colorant, and variations in chromaticity and luminance cannot be avoided in mass production, and a chromaticity selection step is indispensable. Further, since the resin is cured, a colorant cannot be additionally mixed for chromaticity correction. Therefore, since an increase in cost is required to obtain an LED having a desired chromaticity, it has been a problem how to reduce these variations to reduce the cost.
[0007]
The present invention has been made to solve such a conventional problem, and an object thereof is to provide an LED suitable for mass production with improved yield and a method for manufacturing the same.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a surface-mounted light-emitting diode in which a light-emitting element is mounted on a package having external connection terminals, and the package is a substantially cubic package made of a metal core material. a is, has a recess having a light reflecting surface on one side of the package, the package is said concave central a through downward formed over the back-to-back face and said one surface from said one surface is wider two-stage slit The slit is filled with an insulating member, and the light emitting element is mounted across the slit on the bottom surface of the recess, and the recess is sealed with a cover plate. At the same time, the light emitting element is corrected for chromaticity by applying a resin containing either or both of a phosphor and a colorant. And said that you are.
[0009]
The resin is applied to at least one surface of the light emitting element.
[0010]
Further, the resin is applied on the cover plate.
[0011]
The light emitting element is a GaN-based light emitting element.
[0012]
The light emitting element includes In (indium), Ga (gallium), Al (aluminum), and P (phosphorus) elements.
[0013]
Further, another means of the present invention for achieving the above-described object is the method for producing a surface-mount diode according to any one of claims 1 to 5, wherein either one of a phosphor and a colorant is used. Or a step of applying the resin containing both by an ink jet method.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of an LED according to a first embodiment of the present invention, and FIG. 2 is a perspective view of the package of the LED.
[0015]
First, the configuration of this embodiment will be described. In FIG. 1, 10 is a surface-mounted LED. Reference numeral 1 denotes a package in which a metal core material such as Mg, Al, or Cu having a high thermal conductivity of 100 W / (m · K) or more is molded into a substantially cubic shape by injection molding or press molding. The upper surface 1a of the package 1 is formed with a circular bottom surface 1b and a recess 1d having a conical side surface 1c extending from the bottom surface 1b toward the opening. The inner surface of the recess 1d is covered with a reflective film formed by vapor deposition, printing, or plating such as silver plating, except for the element mounting surface.
[0016]
From the upper surface 1a of the package 1 to the upper surface 1a and the lower surface 1e back to back, a slit 1f and a slit 1g wider than the slit 1f are formed so as to divide the package 1 into two vertically. Reference numeral 2 denotes an insulating member such as an adhesive filled in the slit 1f and the slit 1g. The package 1 is divided into two parts in the insulating member 2 to form a pair of electrodes. The bonding portion of the LED element 3 on the bottom surface 1b and the external connection terminal portion of the lower surface 1e are each subjected to surface treatment such as gold plating necessary for bonding.
[0017]
Reference numeral 3 denotes a GaN-based bumped LED element that is a light emitting element formed in advance as a flip chip (FC), and is bonded to both electrode surfaces of the bottom surface 1b of the package 1 by FC bonding across the slit 1f. . 4 is an underfill resin which fills the gap between the LED element 3 and the bottom surface 1b and covers the bonding portion. 5 is a coating resin containing either or both of a phosphor and a colorant, and is applied to at least one surface of the LED element 3. Here, “at least on one surface” is because the chromaticity may be adjusted by simply applying to one surface. Reference numeral 6 denotes a sheet or flat cover plate made of transparent glass or transparent resin which is bonded to the upper surface 1a of the package 1 and sealed inside.
[0018]
Next, the operation of this embodiment will be described. When only the fluorescent material is contained in the coating resin 5, the blue light emitted from the GaN-based LED element 3 hits the fluorescent material in the coating resin 5 and changes to yellow, and is emitted. Since the light that does not fall on the light is emitted as blue, the emitted light becomes white light due to the mixed color of yellow and blue. When the coating resin 5 contains only the colorant, the emitted light is a mixed color of the blue color of the LED element 3 and the color tone of the colorant. Furthermore, when a fluorescent material and a colorant are mixed in the coating resin 5, light emission having a mixed color of white and the color tone of the colorant can be obtained. In this way, an LED having a desired emission color can be obtained.
[0019]
In addition, since it is based on the above effect | action, in order to obtain a desired luminescent color, what is necessary is just to make the coating resin 5 contain either a fluorescent substance or a coloring agent, or both. Moreover, you may mix antioxidant and anti-aging agent suitably as needed. The LED element 3 is not limited to a GaN-based one, but is formed from a compound semiconductor in which four elements of In (indium), Ga (gallium), Al (aluminum), and P (phosphorus) are combined. An LED element may be used, and a desired luminescent color can be obtained by the same action as that of a GaN-based blue LED element.
[0020]
Next, regarding the manufacturing method of this LED 10, the process of applying the coating resin 5 will be described. In FIG. 3, reference numeral 20 denotes a nozzle that discharges the coating resin 5 by an ink jet method. First, the underfill resin 4 is injected and filled into the package 1 after the LED element 3 is mounted, and is cured by heating. Next, the nozzle 20 is brought close to the upper surface of the LED element 3, and the coating resin 5 is discharged and cured by heating. Next, the cover plate 6 is joined to the package 1. In the method of filling the slits 1f and 1g and the slits 1f and 1g with the insulating member 2, first, the slit 1g is processed so as not to reach the bottom surface 1b. Next, the insulating member 2 is filled in 1 g and heated and cured, and then the slit 1 f is processed from the upper surface 1 a until it reaches the slit 1 g. Finally, the procedure is performed in which the insulating member 2 is filled and cured in the slit 1f. In the entire process of manufacturing the LED 10, a simultaneous multiple manufacturing method by batch processing can be adopted using a package substrate in a collective state in which multiple LEDs can be obtained.
[0021]
Next, the effect of LED10 which is this Embodiment is demonstrated. The light extraction efficiency (luminance) is reflected by the inner surface of the recess 1d and is upward in the necessary direction. By using a package substrate which is a collective substrate that can be obtained in large numbers, a large number of processes can be performed at the same time, so that manufacturing costs can be reduced. Since the LED element 3 is joined by FC bonding, it has excellent impact resistance. When sealing is performed using the cover plate 6 having a hygroscopic property and having a linear expansion coefficient similar to that of the package material without using a sealing resin having a large thermal expansion, it is excellent in moisture resistance and heat resistance.
[0022]
Since the package 1 is made of a metal core material with high thermal conductivity, it has far better heat dissipation than conventional LEDs, requires a large current, and is optimal for automotive LEDs that generate a large amount of heat. It is a configuration. Moreover, since it can manufacture by methods, such as injection molding or press molding, a special technique and installation are not required.
[0023]
Since the coating resin 5 is applied by the ink jet method, the resin amount can be finely adjusted, and fine chromaticity adjustment can be performed. As a result, the sorting step based on chromaticity, which was necessary in the past, could be eliminated.
[0024]
Next, a second embodiment of the present invention will be described. FIG. 4 is a cross-sectional view of the LED 20 according to the second embodiment of the present invention. In FIG. 4, the difference from the first embodiment is a place where the coating resin 5 is applied. The coating resin 5 is applied on the cover plate 6. Since the other structure is the same as that of LED10, the same code | symbol and name are provided to the same component, and description is abbreviate | omitted.
[0025]
Next, the effect of the second embodiment will be described. In addition to the same effects as those of the first embodiment, the chromaticity can be easily corrected by replacing the cover plate 6 of the LED 20 with a cover plate 6 newly coated with the coating resin 5. became. In addition, the chromaticity can be adjusted by applying a resin containing a phosphor or a colorant many times to the same product.
[0026]
【The invention's effect】
As described above, according to the present invention, a GaN-based light emitting element is mounted on a package having external connection terminals, and the light emitting element is sealed with a resin containing a phosphor or a colorant. In the LED, the package is a substantially cubic package made of a metal core material, and a concave portion having a light reflecting surface is formed on one surface of the package, and is formed from the one surface to the one surface and the back-to-back surface. A slit that bisects the package is filled with an insulating member, the light emitting element is mounted on the bottom surface of the recess, the package is sealed with a cover plate, and the light emitting diode is phosphor or Since the resin containing either one or both of the colorants is applied, the emission color of the LED can be changed to a desired color, and Time can be improved, excellent heat dissipation, it was possible to obtain a highly reliable surface mounted light emitting LED.
[0027]
Since the ink jet method is used to apply the coating resin to the light emitting element, the resin amount can be finely adjusted, and light emission of an arbitrary color tone can be easily obtained. Further, by applying a coating resin to the cover plate, it becomes easy to change and adjust the emission color of the LED once completed.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an LED according to a first embodiment of the present invention.
FIG. 2 is a perspective view of an LED package according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view showing the LED manufacturing method according to the first embodiment of the present invention.
FIG. 4 is a cross-sectional view of an LED according to a second embodiment of the present invention.
FIG. 5 is a cross-sectional view of a conventional LED.
[Explanation of symbols]
1 Package 1a Upper surface 1b Bottom surface 1c Light reflecting surface 1d Recess 1e Lower surface 2 Insulating member 3 LED element 4 Underfill resin 5 Coating resin 6 Cover plates 10 and 20 LED

Claims (6)

In a surface-mounted light emitting diode in which a light emitting element is mounted and sealed on a package having an external connection terminal, the package is a substantially cubic package made of a metal core material, and has a light reflecting surface on one surface of the package. A recess is formed, and the package is vertically divided into two by a wide two-stage slit from the one surface to the one surface and the back-to-back surface through the center of the recess. The light emitting element is mounted across the slit on the bottom surface of the recess, the recess is sealed with a cover plate, and the light emitting element is either a phosphor or a colorant. The surface mount light emitting diode is characterized in that the chromaticity is corrected by applying a resin containing one or both. .   The surface-mount light-emitting diode according to claim 1, wherein the resin is applied to at least one surface of the light-emitting element.   2. The surface mount light emitting diode according to claim 1, wherein the resin is coated on the cover plate.   The surface-mount diode according to any one of claims 1 to 3, wherein the light-emitting element is a GaN-based light-emitting element.   4. The surface mount diode according to claim 1, wherein the light emitting element includes In (indium), Ga (gallium), Al (aluminum), and P (phosphorus) elements.   6. The method for producing a surface-mounted diode according to claim 1, further comprising a step of applying the resin containing either a phosphor or a colorant or both by an ink jet method. A method for manufacturing a surface-mounted light emitting diode.

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