Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2001-12-14
2004-07-06
Vo, Peter (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S843000, C029S855000, C029S876000, C029S883000, C029S884000, C257S100000, C264S272150
Reexamination Certificate
active
06757969
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to method of fabricating LED assembly, and more particularly, to method of fabricating a string of original colored (E,G,B) high intensity LEDS (Light Emitting Diodes) to be displayed on a screen or used as a traffic light source.
2. Description of the Prior Art
In conventional method of fabricating LED assembly, an epoxy resin added with a hardener molded by baking at high temperature (90° C.~110° C.) is a commonly adopted procedure. For example, in a cited case herein, which was patented by NO3 11269 in Taiwan, a fabrication method by plastic packaging was employed. The material used for fabrication was a plastic resin (an hardener was required to cure its softness at room temperature) applied to the micro structure of a semiconductor surface by coating or spraying, them the later fabricating steps were successively carried out after hardening of the plastic resin. As the package was performed by coating or spraying, the finished surface of the product was somewhat uneven. In addition, such a fabrication method provided by the cited case is only applicable for semiconductor packaging owing to the fact that it is unable to withstand ejecting pressure higher than 40 psi.
Since high intensity blue colored LED has come to practical use, it soon becomes a favorite of multi-media world. Further innovation on precision of light emission angle and uniformity in tint are asked that can not be attained with a conventional resin treatment.
Filling epoxy resin or silicone rubber in a LED assembly housing by heating at a temperature above 120° C. in an oven, the rate of yield scarcely exceeds 90% with disqualified results in disorganized disposal of elements, inadequate quantity of resin attachment, and unevenness of surface. Besides, a cracked resin package is not repairable and inadvertent spattering of resin in the front of surface an unit LED causes degrading of brightness.
High intensity blue or green LED lighting source should be reliably made watertight if it is to be installed outdoor. However, such an aim is hard to be attained by a conventional method of driving in an oven after instilling a resin with a low cost.
In order to overcome the shortcomings inherent to the conventional technique described above, the present inventor has delved into this matter with a long time efforts and came to realization of the present invention.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide method of fabricating LED assembly by using polyacrylic resin as a essential packaging material and applying a pressure above 40 psi to integrally form a watertight contour of a string of LED assembly by injection molding process so as to obtain a good looking, smooth surfaced appearance of the product.
It is another object of the present invention to provide method of fabricating LED assembly by using an innovative plastic resin injection machine to save 50% time needed in the whole stages of fabrication so as to minimize production cost internationally competitive with other leading countries in this field of technology.
In the method of the present invention, the time duration required for polyacrylic resin injection per round is only about 40 sec with temperature descending from 110° C. down to below 60° C. fully in compliance with internationally standardized LED fabrication specification and increase of 130 times production speed compared with general conventional method of fabrication. Besides, in case the housing of the LED assembly is cracked, it is 99% repairable by fusing plastic resin of the housing.
To enable a further understanding of the innovative and technological content of the invention herein, refer to the detailed description of the invention and the accompanying brief description of the drawings appended below. Furthermore, the attached drawings are provided for purposes of reference and explanation, and shall not be construed as limitations applicable to the invention herein.
REFERENCES:
patent: 5036248 (1991-07-01), McEwan et al.
patent: 5278235 (1994-01-01), Tajima et al.
patent: 5313729 (1994-05-01), Sakai et al.
patent: 5382811 (1995-01-01), Takahashi
patent: 5808592 (1998-09-01), Mizutani et al.
patent: 08-202290 (1996-09-01), None
Nguyen Donghai D.
Rosenberg , Klein & Lee
Vo Peter
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