摘 要 在白光二極體之藍光溢漏之研究 的論文中，我們提出並演示了解決熒光粉時藍光洩漏相關問題（例如，眼睛損傷）的解決方案- 轉換後的白光發光二極管 (pcW-LED) 過熱。發現在正常運行期間溫度高於設定值時，熒光粉嚴重熱猝滅時會出現潛在的藍光。高溫會導致熒光粉降解，使相關色溫升高，藍光和黃光的比例也會升高。這將導致用戶眼睛不可避免地暴露在低質量或藍光洩漏的白光中。需要找到解決藍光洩漏問題的方法。原則上，當發生過熱時，可以通過停止 pcW-LED 的工作來防止這種藍光洩漏。可以通過以下方式之一完成： (1) 發生過熱時，通過減小電路中的電流來消除過熱現象。 (2) 當發生過熱時，使封裝體積變暗以抑制白色 LED 的亮度。 當由於老化而發生過熱時，電流的減少和封裝體積的變暗將抑制白色 LED 的亮度。由於輸出通量顯著衰減並且燈變得更暗。用戶可以理解更換禁用的白色 LED。 本研究重點介紹了兩種有效的方法，即被動法和主動法來防止藍光洩漏的影響。 在主動防藍光漏光的方法中，我們會開始設計主動保險絲，引入合適的熱敏電阻電子元件，具有合適的熱特性，以保護用戶免受老化白光LED的藍光危害。過熱狀態下產生的熱量將用於開啟熱敏電阻的高阻模式，以降低電路中的電流。對應電流的減小，過熱消失，產生低電平輸出光通量。至此，過熱問題得到解決。同時，低水平的光通量通知用戶更換新的 LED 燈。 在被動防藍光洩漏的方法中，將研究名為晶體納米纖維素（CNCs）的熱致變色材料的性能並進行精確表徵。基於封裝體積結構中過熱和藍光洩漏的溫度行為和CNCs的熱光學特性，將CNC引入pcW-LED的封裝體積結構中。過熱時CNCs會變暗，然後吸收藍光並導致燈的亮度受到抑制。低水平的光通量有助於用戶的眼睛避免暴露在藍光下，並通知用戶更換新的 LED 燈。在正常操作條件下，CNCs 不會顯著影響燈的亮度。 ;Abstract In the dissertation of “Study of blue light leakage of white light light emitting diode”, we proposed and demonstrated solutions for solving problems related to blue light leakage (e.g., eye damage) when phosphor-converted white light-emitting diodes (pcW-LEDs) overheat. It was discovered that a potential bluish light occurs when serious thermal quenching for phosphor as the temperature is higher than the set value in a normal operation duration. The high temperature will cause degradation of phosphor so that the correlated color temperature will increase, and so does the ratio between blue and yellow light. This will cause unavoidable exposure to the low-quality or blue light leakage white light for the eyes of the user. It is demand to find the solution for the problem of blue light leakage. In principle, this exposure to blue light leakage can be prevented by stopping the working of pcW-LEDs when overheating happens. It can be done by one of the following ways: (1) Remove the overheating phenomenon by reducing the current in the circuit when overheating happens. (2) Darkening the packaging volume to suppress the brightness of a white LED when overheating happens. The reduction of electrical current and darkening of packaging volume will suppress the brightness of a white LED when overheating is taking place due to aging. Since the output flux is significantly decayed and the lamp becomes dimmer. The user can understand to replace the disabled white LED. This research focuses on two effective methods called passive method and active method for preventing the effect of blue leakage. In the method of actively anti-blue light leakage, we will start to design an active fuse by introducing an appropriate electronic element of the thermistor with a suitable thermal characteristic to protect the user from the blue hazard of the aging white LED. The heat generated in an overheated state will be used to turn on the mode of high resistance of the thermistor to make reduce the current in the circuit. Corresponding to the decrease of current, the overheated will vanish and a low-level output luminous flux is generated. Thus, the overheating was solved. At the same time, the low level of luminous flux informs the user to replace a new LED lamp. In the method of passively anti-blue light leakage, the property of the thermochromic material named crystal nanocellulose (CNC) will be investigated and making precise characterization. Based on the temperature behavior of overheating and blue light leakage in the packaging volume structures and thermal-optical properties of CNC, the CNC will be introduced in the packaging volume structures of pcW-LEDs. CNC will be darkened when overheating happen, then absorbing the blue light and causing the suppression in the brightness of the lamp. The low level of luminous flux helps the user′s eyes to avoid exposure to bluish light and informs the user to replace a new LED lamp. Under the normal operation condition, CNC do not significantly affect the brightness of the lamp.
