TW201336111A - Surface treatment methods for LED housing packages - Google Patents

Abstract

Surface treatment methods for light-emitting diode (LED) housing packages are presented. In one embodiment, a surface treatment method includes forming an LED housing with fluoro-containing polymer coating. The LED housing is subsequently performed by surface treatments to improve surface properties of the fluoro-containing polymer coating. An LED chip is bound on the LED housing and mounted by filler covering the LED chip, wherein interfacial adhesion between the fluoro-containing polymer coating and the filler has been due to surface treatments.

Description

Surface treatment method of light-emitting diode housing

The present invention relates to a light-emitting diode structure, particularly a light-emitting diode housing having a surface coating of a fluorinated polymer and a light-emitting diode structure thereof.

Improving light extraction efficiency has always been an important issue in the development of light-emitting diodes. One reason why the light extraction efficiency is difficult to increase is that the internal reflection or refraction of the interface between the light-emitting diode wafer itself and the peripheral elements causes the light emitted by the wafer to be absorbed by the peripheral elements instead. In order to solve this problem, a casing containing titanium oxide is usually used to coat the light-emitting diode. Titanium dioxide can increase the reflectance of visible light. Generally such shells are made of polyphenylhydrazine (PPA) engineering plastics. However, the disadvantage of such a method is that titanium dioxide gradually turns the color of the outer shell of the polyphenylene hydrazine from white to yellow, so the light extraction efficiency also gradually decreases.

The prior art provides another solution, as described in U.S. Patent Publication No. US 20100032702, which replaces polyphenylphthalide with a fluorine-containing engineering plastic. The technique of this patent consists in shaping the fluorinated polymer into an integral shell of the light-emitting diode by injection molding. Although this technology can solve the problem of yellowing of polyphenylene benzoquinone, since the price of fluorinated polymer is very expensive, the overall outer casing of the light-emitting diode will greatly increase the cost, and it is difficult to implement it universally in various light-emitting diodes. On the body component.

The Republic of China Patent Publication No. TW 201135981 discloses the use of a light-emitting diode housing having a fluorinated polymer surface coating, which is covered by a fluoropolymer surface coating covering a non-fluoropolymer engineering plastic. Light extraction efficiency, increase the overall brightness of the LED device and reduce manufacturing costs.

In the subsequent packaging process, the package filling used is epoxy or silicone. The bond between the package filler and the light-emitting diode housing having a fluorinated polymer surface coating is poor, and peeling of the package filler is liable to occur due to the surface characteristics of the fluorine compound.

In order to solve the dilemma faced by the prior art, embodiments of the present invention provide a surface treatment method for a surface of a light-emitting diode of a fluorine-containing polymer. The fluorinated polymer surface coating covers a housing made of a non-fluoropolymer engineering plastic. The adhesion between the fluorinated polymer and the filler is significantly enhanced after the surface treatment step.

According to an embodiment of the invention, a surface treatment method for a light-emitting diode housing, the surface of the light-emitting diode housing containing a fluorine-containing polymer, comprising: providing a casing made of a non-fluorinated polymer; a surface coating covering at least a portion of the housing, the surface coating being made of a fluorinated polymer dispersion and for reflecting light emitted by the LED substrate disposed on the housing; The diode housing is surface-treated to improve the surface properties of the fluorinated polymer; a light-emitting diode chip is packaged on the light-emitting diode housing, and the light-emitting diode wafer is covered with a filler. The surface bonding step significantly improves the bondability between the fluorinated polymer and the filler.

In another embodiment, the step of applying a surface treatment comprises applying a corona treatment or a laser treatment, a high concentration alkali treatment, a fire treatment, or a combination of the above steps, wherein the high concentration alkali treatment step comprises applying It is treated with a commercially available Teflon surface treatment lye.

In order to make the invention more apparent, the following detailed description of the embodiments and the accompanying drawings are as follows:

The following is a detailed description of the embodiments and examples accompanying the drawings, which are the basis of the present invention. In the drawings or the description of the specification, the same drawing numbers are used for similar or identical parts. In the drawings, the shape or thickness of the embodiment may be expanded and simplified or conveniently indicated. In addition, the components of the drawings will be described separately, and it is noted that the components not shown or described in the drawings are known to those of ordinary skill in the art, and in particular, The examples are merely illustrative of specific ways of using the invention and are not intended to limit the invention.

A primary embodiment and feature of the present invention is a surface treatment method for a light-emitting diode housing that provides a surface fluorinated polymer. The shell made of engineering plastic coated with a non-fluoropolymer on the surface of the fluorinated polymer surface significantly improves the bondability between the fluorinated polymer and the filler after the surface treatment step. In accordance with an embodiment of the present invention, the outer casing of the light emitting diode package can have a variety of functions. In general, it can be used as a package for carrying LED chips, providing LED chip chip package suitable position and alignment, thereby electrically connecting to the circuit board. For example, the package may contain phosphors, and the blue LED chip may be combined with a green phosphor and a red phosphor to generate white light.

First, for the light-emitting diode housing suitable for the embodiment of the present invention, and with the drawings, the detailed description is as follows:

1A through 1D show various embodiments of an outer casing of a light-emitting diode wafer having a recess of the present invention. As shown in FIG. 1A, the outer casing 100 for carrying the light-emitting diode chip includes a metal frame 101 and a casing 102 connecting the metal frame 101. The metal frame 101 can selectively penetrate the housing 102 as indicated by the dashed lines in the figure. The metal frame 101 is made of an electrically conductive metal. The housing 102 is formed of a non-fluorinated polymer such as polyphenylene hydrazine (PPA), liquid crystal polymer (LCP) or other suitable engineering plastic. The housing 102 forms a recess 103 as a location for carrying the LED wafer. A recess 103 can place one or more LED wafers. The groove 103 allows the light to be reflected at a desired angle, and the depth, the angle of the wall, the size, and the like can be determined by the designer.

Referring also to FIG. 1A, the outer casing 100 further includes a surface coating 104 covering at least a portion of the surface of the housing 102. The surface coating 104 is made of a fluorinated polymer dispersion for reflecting light emitted by a light-emitting diode wafer placed on the housing 102. The surface coating 104 shown in FIG. 1A covers the surface of the housing 102 above the metal frame 101. The surface coating 104 further includes an extension portion 104a covering one end of the metal frame 101. 1B shows an outer casing 110 of a light-emitting diode wafer according to another embodiment, which differs from FIG. 1A in that the surface coating 114 covers only the surface of the recess 103. 1C shows a housing 120 of a light-emitting diode wafer according to another embodiment, which differs from FIG. 1B in that the surface coating 124 covers a portion of the top surface 102a of the housing 102 in addition to the surface covering the recess 103. A portion of the housing 102 above the metal frame 101 is exposed and not covered by the surface coating 124. 1D shows an outer casing 130 of a light-emitting diode wafer according to another embodiment, which differs from FIG. 1A in that a surface coating 134 covers the entire surface of the housing 102.

1A through 1D illustrate various variations of the surface coating in embodiments of the present invention which are related to the formation process of each surface coating. The various aspects of the invention can be accomplished after the metal frame and housing have been fabricated using suitable coating techniques, such as sputtering, spraying or impregnation, through a suitable mask, or by etching to remove excess coating after coating. Surface coating of the aspect. 2 is a non-recessed planar light-emitting diode chip housing 200 that includes a metal frame 101 that covers the entire surface of the housing 202 above the metal frame 101. Embodiments of the invention are not limited to the above, and those skilled in the art will appreciate that the surface coating of the present invention includes various embodiments of light that can be reflected by a light-emitting diode wafer disposed on the housing.

As described above, the surface coating is made of a fluorinated polymer dispersion. According to an embodiment of the present invention, the fluorinated polymer surface coating is stable in color, can reflect visible light, and has solder resistance capable of withstanding a soldering process of 260 ° C to 280 ° C for more than 3 minutes. In accordance with an embodiment of the present invention, the fluorinated polymer surface coating has a photopic reflectance in the wavelength range of 380 nm to 780 nm of at least about 80%.

The fluorinated polymer dispersion comprises a fluorinated polymer and other suitable fillers. The fluorinated polymer dispersion has the property of being subjected to a coating process to deposit it on the casing, and the coating process can be by spraying, impregnation or other various suitable techniques.

The fluorinated polymer in the fluorinated polymer dispersion contains polymers of various molecular weights, and the monomers of the polymer may have from 2 to 8 carbons. The fluorinated polymer may be a homopolymer of a single monomer or a copolymer of a plurality of monomers, or a combination of the two. The monomer may or may not contain fluorine. For example, the fluorine-free monomer may be ethylene or propylene; the fluorine-containing monomer may be tetrafluoroethylene (TFE), vinyl fluoride (VF), vinylidene fluoride (VDF). , hexafluoroisobutylene (HFIB), hexafluoropropylene (HFP) or perfluoro(alkyl vinyl ether (PAVE), which is not limited thereto. The perfluoroalkyl group of the above PAVE comprises 1 Up to 5 carbon atoms, which may be linear or branched, such as perfluoro(methyl vinyl ether, PMVE), perfluoro(ethyl vinyl ether) , PEVE), perfluoro(propyl vinyl ether, PPVE), and perfluoro(butyl vinyl ether (PBVE). Various fluorination polymerizations of the present invention are illustrated by way of example The material may be selected from the following and various combinations thereof, but is not limited thereto: a copolymer of TFE and HFP, called perfluorinated ethylene-propylene (FEP); a copolymer of TFE and PAVE, Perfluoroalkoxy fluorocarbon (perfluoroalkoxy fluorocarbon resin, PFA); a uniform polymer of VDF, called PVDF; a copolymer of ethylene and TFE, called ethylene tetrafluoroethylene (ETFE); a homopolymer of VF, called PVF A homopolymer of chlorotrifluoroethylene, known as PCTFE; a copolymer of chlorotrifluoroethylene and ethylene, known as ECTFE.

Next, the light-emitting diode housing of the fluorine-containing polymer described in the above examples was subjected to surface treatment. Generally, the filler used in the package mainly contains epoxy or sillcon, and the bonding property between the package filler and the fluorinated polymer is poor, and the surface treatment step can improve the subsequent process. LED chip package process yield.

According to an embodiment of the present invention, a suitable surface treatment method mainly includes, but is not limited to, the following surface treatment methods: corona treatment or laser treatment, high concentration alkali treatment, and commercially available Teflon surface treatment alkali. Liquid treatment, and fire baking treatment. For example, the efficacy of corona treatment or laser processing mainly focuses on the applied power multiplication and the multiplication effect of the processing time. For example, a processing time in which the applied power is large is short, or a processing time in which the applied power is small is long.

None of the above three surface treatment methods change the appearance of the light-emitting diode casing, but the O/C value (carbon-oxygen ratio) of the surface can be changed. The O/C value after surface treatment can be measured by Electron Spectroscopy for Chemical Analysis (ESCA) instrument measurement. In a specific example, after the above three methods are moderately treated, the surface of the LED housing may be more likely to adhere to other substances. If the surface treatment is not carried out, the consequence is that the moisture in the air will affect the performance of the LED structure in the interface. Seriously, any material contacting the surface will peel off the surface characteristics of the fluorine compound.

In areas with high sulfur-containing moisture, sulfur molecules may penetrate into the package and combine with the Ag bonded to the LED wafer, producing black AgS, which in turn leads to reduced LED performance.

If the encapsulating filler is directly peeled off from the surface of the LED housing, the phosphor is doped in the silicone and forced to leave its active position. The white LED will not be generated and the LED wafer will also be in direct contact with the air to disable the LED mechanism. It should be noted that although the above disclosed embodiments only exemplify three surface treatment methods, but are not intended to limit the present invention, other surface modification process steps having the same effect can be applied to improve the LED housing and filler. Interfaciality.

3 is a diagram showing a package structure including a surface-treated LED housing and an LED chip according to an embodiment of the present invention. Referring to FIG. 3, the LED housing 310 of the present embodiment can be used as an alternative to the LED housing shown in FIGS. 1A-1D, and subjected to surface treatment (for example, corona treatment, high concentration) as described in the above embodiments. Alkali treatment and/or fire treatment) improve surface properties. The outer casing 310 includes a pedestal having a recess on which the LED wafer 350 is carried. The LED wafer 350 can be any suitable LED wafer, such as an LED wafer that emits light in the range of UV light to infrared light. The LED chip 350 is connected to the lead frame 320 by a metal wire 340. Filler 330 fills the recess in the housing base and covers the LED wafer 350. The bottom of the housing base is in contact with a heat sink 360. The LED housing 310 is bonded to a substrate (for example, the LED substrate 380 covering the dielectric layer 370) via solder 365 to form a reliable LED package structure 300.

The present invention has been disclosed in the above various embodiments, and is not intended to limit the scope of the present invention. Any one of ordinary skill in the art can make a few changes and refinements without departing from the spirit and scope of the invention. . The scope of the invention is defined by the scope of the appended claims.

100. . . shell

101. . . metal rack

102. . . case

103. . . Groove

104. . . Surface coating

104a. . . Extension

110. . . shell

114. . . Surface coating

120. . . shell

124. . . Surface coating

102a. . . Top surface

130. . . shell

134. . . Surface coating

300. . . LED package structure

310. . . Light-emitting diode housing

320. . . Lead frame

330. . . Filler

340. . . Metal wiring

350. . . LED chip

360. . . Heat sink

365. . . solder

370. . . Dielectric layer

380. . . LED substrate

1A through 1D are cross-sectional views showing an outer casing of various light emitting diodes having grooves in accordance with an embodiment of the present invention.

2 is a cross-sectional view showing an outer casing of a light-emitting diode having no grooves in accordance with an embodiment of the present invention.

3 is a diagram showing a package structure including a surface-treated LED housing and an LED chip according to an embodiment of the present invention.

300. . . LED package structure

310. . . Surface treated light-emitting diode housing

320. . . Lead frame

330. . . Filler

340. . . Metal wiring

350. . . LED chip

360. . . Heat sink

365. . . solder

370. . . Dielectric layer

380. . . LED substrate

Claims (9)

A surface treatment method for a light-emitting diode housing, comprising: forming a light-emitting diode housing of a surface fluorine-containing polymer; applying a surface treatment to the light-emitting diode housing to improve surface properties of the fluorinated polymer Packaging a light-emitting diode chip on the light-emitting diode housing, and covering the light-emitting diode wafer with a filler; wherein the surface treatment step significantly increases the relationship between the fluorine-containing polymer and the filler Bonding. The surface treatment method of the light-emitting diode housing of claim 1, wherein the step of forming the light-emitting diode housing comprises: providing a casing made of a non-fluorinated polymer; and forming a surface A coating covers at least a portion of the housing, the surface coating being formed from a fluorinated polymer dispersion and used to reflect light from a light emitting diode wafer disposed on the housing. The surface treatment method of the light-emitting diode housing according to claim 2, wherein the housing is made of PPA engineering plastic. The surface treatment method of the light-emitting diode housing of claim 3, wherein the housing further comprises a recess for placing the light-emitting diode wafer, the surface coating covering only the surface of the recess . The surface treatment method for a light-emitting diode housing according to claim 1, wherein the fluorinated polymer comprises a vinyl polymer of a vinyl floride, a perfluoroalkoxy fluorocarbon resin. a homopolymer or a homopolymer of vinylidene fluoride. The surface treatment method of the light-emitting diode housing according to claim 1, wherein the step of applying the surface treatment comprises applying a corona treatment or a laser treatment, a high-concentration alkali treatment, a fire treatment, or the above The combination of steps. The surface treatment method of the light-emitting diode housing according to claim 6, wherein the surface coating of the fluorinated polymer is subjected to a surface treatment step, thereby causing the fluorinated polymer to be lifted between the filler and the filler. Jointability. A surface treatment method for a light-emitting diode housing according to claim 1, wherein the filler comprises a filler capable of dispersing visible light. The surface treatment method of the light-emitting diode housing of claim 1, wherein the filler comprises an epoxy resin, a silicone rubber, or a combination thereof.