- 學位論文
固晶膠導熱係數與PCB板材設計對於LED封裝體之影響
The Effects of Die Attach and PCB on LED Package
摘要
本論文研製之固晶膠與PCB基板對於LED封裝體之影響，其中熱阻是指材料對溫度傳導的阻礙效果。熱阻的單位為℃/W，係指當發光二極體點亮後，熱傳導達到穩定狀態的時候，晶片表面每W所耗散的溫度，發光二極體PN接面的溫度與導線架每W溫度差，或連接PCB基板至環境溫度之間每W的溫度差就是LED的熱阻。 文中分別提到接面至導線架每W溫度差為Rj-s、接面至環境溫度每W溫度差為Rj-a。其中Tj為發光二極體PN接面的溫度，Ts、Ta分別為導線架與PCB接點溫度與環境溫度。以有限原素法建立模型加以分析，再以熱阻測試儀，分別針對使用四種不同導熱係數固晶方式與三種PCB材質分析量測其Tj，探討其對於發光二極體Rj-s、Rj-a的差異，進而影響不同封裝發光二極體之Tj、光效與壽命。研究中Tj最大差異約100℃，穩態亮度最大差異達26％，CIE Shift ccx、ccy相差分別約0.0245、0.0296。壽命約可由23,000hrs提升至73,000hrs。由實驗結果得知導熱係數的差異確實會影響光效與壽命。且模擬之溫度影響驅勢與實驗結果接近，後續如有新材料可以模擬方式先行確認其效果。
並列摘要
In this paper, the effects of Die attach and PCB on LED package. Thermal conductivity is the material obstacles to the temperature effect. Thermal resistance units of ℃/W. It means when driven light emitting diodes, steady-state heat conduction, wafer surface temperature dissipation per W. Light-emitting diodes PN junction temperature and the temperature difference between the lead frame per W, or connection PCB substrate the temperature difference between ambient temperature per W, it is LED’s thermal resistance. Mentioned in this paper were junction to lead frame temperature difference per W call Rj-s, junction to ambient temperature difference per W call Rj-a. Wherein Tj is a light-emitting diode PN junction temperature, Ts is the temperature of the lead frame with PCB contacts, Ta is the ambient temperature. To modeled using the finite elements method to analyze. then use Thermal resistance tester, Respectively, use four different thermal conductivity of die bonding process with the three kinds of PCB material analysis measurements which Tj. Explore for light-emitting diodes Rj-s, Rj-a difference, thereby affecting different package emitting diodes, Tj and optical efficiency and lifetime. The maximum difference between the study Tj about 100 ℃, the steady-state maximum difference of brightness 26%, CIE Shift ccx, ccy difference of approximately 0.0245,0.0296. Approximately 23,000 hrs lifetime may increase to 73,000 hrs. The experimental results show that the thermal conductivity difference does affect the luminous efficiency and lifetime. And temperature simulation and experimental results are close, the follow-up if the new material can simulate the ways ahead to confirm its effectiveness.