COVER LAYER WITH HIGH THERMAL RESISTANCE AND HIGH REFLECTIVITY FOR A PRINTED CIRCUIT BOARD

摘要

A cover layer of a printed circuit board has a polymer film, a reflective composite layer and an adhesive layer. The polymer film has a melting point greater than 260° C. The reflective composite layer is mounted on one side surface of the polymer film and has a first reflective pigment. The adhesive layer is mounted on another side surface of the polymer film. Also, at a range of wavelength where a reflectivity of the cover layer is greater than 89%, absorption of the polymer film to the same range of wavelength is less than 35%. The cover layer is laminated on a printed circuit board and after surface mount technology process at a temperature ranging from 160° C. to 320° C., the cover layer has a reflectivity over 89% without yellowing and delamination.

主权项

1. A cover layer with high thermal resistance and high reflectivity for a printed circuit board, the cover layer having:
1) a polymer film having
a thickness ranging from 2 μm to 125 μm;a melting point greater than 260° C.; andtwo side surfaces opposite to each other; 2) a reflective composite layer mounted on one of the side surfaces of said polymer film and having
a thickness ranging from 2 μm to 30 μm; anda first reflective pigment with a refractive index greater than 1; and 3) an adhesive layer mounted on the other side surface of the said polymer film and having
a thickness ranging from 10 μm to 75 μm; wherein from wavelength 415 nm to 700 nm, the reflectivity of the cover layer of the printed circuit board is greater than 89% and absorptivity of the polymer film is less than 35%.