EHD結構製備與其在LED散熱應用( I )

Abstract

本計劃預計以陶瓷材料為LED基板製備Electrohydrodynamics (EHD)結構之散熱模組，利用施加於EHD結構電壓來產生離子風，將散熱模式轉為強制對流、可大幅提升其散熱能力，更可解決介電層導熱性不佳所造成導熱的瓶頸。由於陶瓷材料與LED晶片的熱膨脹係數差異較小，更可確保散熱模組之穩定性及可靠度。另外、由於以EHD結構取代傳統散熱鰭片更可降體整體散熱模組體積、重量及成本，更可使其應用場合更具彈性。在LED模組的基板製作電極更可將電極間距降低至數十微米，可有效降低操作電壓並增加熱傳效果。故本計劃將針對EHD電路與LED製程之整合進行研究，並針對此散熱機制進行製作、量測與分析。規劃之研究流程共分為兩年執行並包含兩個主要執行工作：[第一年] 陶瓷基板微電極技術開發與單晶LED模組數值模擬、 [第二年] 具微電極結構之單晶及陣列式多晶LED模組與製程開發，並針對低密度鰭片散熱模組開發。開發過程中將使用下述四樣分析方法來進行研究開發：[第一年]（一）數值分析及最佳化、（二）實驗系統量測與分析 [第二年]（三）紅外線測溫儀分析比對、（四）流場可視系統量測與比對分析。期能藉由此設計解決高溫問題對相關產品所造成其效率、穩定性及壽命性能低落之問題。

The present project proposes an embedded Electrohydrodynamics (EHD) structure upon ceramic package to augment the heat transfer performance of the whole heat sink module. The proposed EHD electrode can generate ionic wind to turn the major heat transfer mechanism from natural convection into force convection, leading to a significant rise of heat dissipation without the penalty of noise. Moreover, the present method can lift the low heat dissipation problem caused by the dielectric layer. This design can be easily implemented into the ceramic package to ensure the reliability of thermal module. In addition, the much lower weight of the present EHD device can substantially reduce the weight of the thermal module, and becomes more flexible in practical thermal design. With the help of a much closer EHD electrode design (around tens of m), the supplied voltage of the present EHD design can be further lower. The overall project is to develop a high power LED module integrated with the EHD thermal module, including the thermal design and the real LED module. The project includes two phases. In the first year, the objective is to develop the ceramic package having EHD cooling mean along with numerical simulation for the single chip module. The second year is to fabricate the single-chip thermal module and extend its use to multi LED array chip and the whole thermal module. The present project plan to adopt four kinds of analyzing methods to explore the fundamental characteristics of EHD LED module, including numerical analysis and its associated optimization, experimental verification and its further improvement, IR flow field examination, and systematic comparison and adjustment amid measurements and simulation. Through the foregoing approaches, high efficient and reliable LED module can be fabricated