A Simple Package Technique of Light Emitting Diode for Enhancing Illuminant Quality
The purpose of this thesis is to fabricate an LED module with low half intensity angle(HIA) ,and to use this module to form a line source with optical performance comparable to that of a CCFL .In addition ,heat dissipation of the LED module on different sub-mounts is also investigated .
The LED modules were formed by first etching a through si via on silicon substrate using wet etching technology for light confining .Then a thin layer of metal was deposited on to the via to reflect the lights emitted from the LED .The LED die was attached to the Si sub-mount with electrodes ,and the connections between the LED and the Si sub-mount were completed by wire bonding .Finally ,the LED modules were obtained by positioning the Si substrates onto the Si sub-mounts using UV epoxy .
The optical performance of the LED module was simulated by Lighttools .For the si substrate with a thickness of 400 £gm ,a simulated HIA of 36 o was obtained .Using six-LED package ,a 3-cm line source with 84.8% output uniformity was simulated .On the other hand ,the measured HIA of a LED module ,and the uniformity of 3-cm line source are 38 o and 84.8% ,respectively.
The thermal resistance of the si sub-mounts were also investigated .The different structures of the sub-mount were proposed ,namely ,LED to Copper case ,LED to Si sub-mount to Copper case ,and LED to Si sub-mount with Copper filled via to Copper case .The estimated thermal resistance of the sub-mounts are 13 W/mk¡B19.4 W/mk and 34.7 W/mk .We believe that the large thermal resistance of the Si sub-mount with Copper filled via is primarily caused by 800 £gm thick substrate .
Advisor:Mei-Ying CHang; Yi-Jen Chiu; Ting-Chang Chang; Ann-Kuo Chu
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:package light emitting diode led
Date of Publication:06/20/2008