冷陰極螢光燈置入背光模組時，不可避免地在燈管與鋁背板間會產生寄生電容，導致洩漏電流，進而影響各燈管之電流，改變背光源之發光特性。因此，大型背光模組採用多管冷陰極螢光燈時，關鍵在於如何均衡驅動，以達到均勻之面光源輸出。
本論文旨在探討冷陰極螢光燈設置於直下型背光模組所產生的電流洩漏效應，並根據阻抗匹配原理，利用電容所組成之簡單電路，達到均衡多燈管電流之目的。本研究採用半橋串聯諧振並聯負載換流器架構，配合升壓變壓器，產生一交流高壓，同時驅動多支冷陰極螢光燈。此電路架構配合負載共振電路，配置適當大小之電容，可使燈管電流趨於一致，並根據一系列的實驗結果，定出單、雙高壓驅動多燈管系統可達均流目標範圍內之最大總電流誤差及最小阻抗比準則，以便提供後續設計者參考。
本論文針對16支冷陰極螢光燈管應用於32吋液晶顯示器背光模組，藉由模擬設計完成單、雙高壓驅動電路及電容均流電路，並經實驗結果驗證其可行性、實用性及正確性。

When multiple cold cathode fluorescent lamps (CCFLs) are set up in a backlight module, parasitic capacitances are inevitably existent between the lamps and the aluminum back-plank. These parasitic capacitances are different from each other in introducing different leakage currents, and in turn cause current imbalance between lamps with undesired unequal brightness of the backlight module. In order to tackle this current imbalance problem, it relies critically upon a balance driving scheme.
This thesis adopts the impedance-matching principle for a uniform light output. A detailed analysis and design of the balance circuit is implemented in a direct-type backlight module, which employs a series resonant parallel-loaded inverter with a transformer to generate a high AC voltage to drive multiple lamps. Adding appropriate capacitors on the load resonant circuits helps alleviate the discrepancy among lamp currents. Based on the experimental results, the maximum total current deviation is defined as an index of the current imbalance for multiple lamps system. Accordingly, the minimum impedance ratio can be provided for the designers to achieve balance driving.
A prototype of the multi-lamp driving circuit with balance capacitors is designed and built for a backlight module with 16 lamps in a 32-inch liquid crystal display (LCD). Simulation and experimental results demonstrate the effectiveness and feasibility of the current balance scheme.

中文摘要 I
英文摘要 II
目錄 III
圖表目錄 V
第一章 簡介 1
1-1研究背景 1
1-1-1平面顯示器概述 1
1-1-2背光模組概述 3
1-2研究動機 7
1-3本文大綱 9
第二章 冷陰極螢光燈管之驅動電路 10
2-1冷陰極螢光燈之常見驅動架構 10
2-2多燈管均流技術 13
2-3單管冷陰極螢光燈之測試電路 16
2-4多管冷陰極螢光燈之單高壓驅動架構 18
2-5多管冷陰極螢光燈之雙高壓驅動架構 22
第三章 背光模組之特性分析 24
3-1冷陰極螢光燈管之負載特性分析 24
3-1-1負增量電阻特性 24
3-1-2電流控制型負增量電阻之電路穩定特性 25
3-2冷陰極螢光燈管之電氣特性分析 27
3-3背光模組之洩漏特性與等效模型 31
3-3-1 背光模組之電流洩漏特性 31
3-3-2 背光模組之等效模型 32
第四章 多管冷陰極螢光燈之電容均流電路分析與設計 38
4-1多管冷陰極螢光燈之電容均流電路設計 38
4-1-1電容均流電路設計考量 39
4-1-2電容均流電路設計準則 42
4-2多管冷陰極螢光燈之電容均流電路特性分析 43
4-2-1燈管電流與操作頻率對單高壓驅動之均流特性 44
4-2-2均流電容對單高壓驅動之均流特性 46
4-2-3燈管電流與操作頻率對雙高壓驅動之均流特性 53
4-2-4均流電容對雙高壓驅動之均流特性 54
4-2-5單、雙高壓驅動之總電流誤差 61
4-2-6單、雙高壓驅動之最小阻抗比 64
4-3電路模擬與實驗量測 66
4-3-1單高壓驅動電路模擬 66
4-3-2單高壓驅動電路實測波形 71
4-3-3雙高壓驅動電路模擬 76
4-3-4雙高壓驅動電路實測波形 82
第五章 結論與未來研究方向 90
參考文獻 92

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