摘要
本文在探討LED牙科燈之光學設計，並要求符合國際的標準BS EN ISO 9680 (1996)。由於一般傳統牙科燈採用鹵素燈，其光源含有紫外線到紅外線波段的光譜，若長期照射紫外線可能導致病人的皮膚受到傷害，長期照射紅外線則讓病人感到灼熱與不適，並且使得醫生的專注力下降。LED光源為冷光光源，不但可免除這些缺點，同時具有低耗電、長壽命、波長、強度、色溫可調控等優點，故本研究探討以LED光源為牙科燈應用之研究和設計。 在光學設計中，利用TracePro光學模擬軟體來建構及分析我們的設計。本文之LED牙科燈主要利用4顆LED光源，搭配反射杯來提升均勻度及縮短收光空間，再經由橢圓反射鏡完全地收斂0度到45度的光線，並且以多段式橢圓反射鏡來達到無影的條件。模擬中利用發光效率與均勻度來作為選定參數的標準。首先，利用發光效率與均勻度對橢圓反射鏡焦距（f1）變動的曲線找出交點為起始參數，其次，增加反射杯來收斂大於45度以上之光線，再調整4個光源的相對位置來達到所需的光形，最後以多段式橢圓反射鏡來達到無影的要求。根據此方法，在距離牙科燈700 mm處之直徑50 mm圓內做出最佳化之設計。此LED牙科燈整體的尺寸為107 × 114 × 67 mm3。
並列摘要
In this article, we report a design of a new shadow-free dental operating light using light-emitting diode (LED) sources, which conforms to the internal standard – BS EN ISO 9680 (1996). Traditional dental light uses a halogen lamp which includes UV to infrared radiation, so when a patient is exposed to a halogen lamp over an extended period of time, the patient would feel uncomfortable because of heat. Furthermore, it has been observed the heat generated from the halogen light would make doctors feel less focused. In addition, LEDs have many advantages like cold light, low power consumption, long lifetime, wavelength controllable and no mercury. For these reasons, LEDs are employed as light sources to reduce heat in a dental operating light. In our design, four white LEDs with small cups and multi-level elliptical reflectors were employed to produce an efficient and shadow-free dental light by a commercial simulator, TracePro. According to the efficiency and uniformity, the parameters of elliptical reflector, including f1, f2, and L, are determined. The elliptical reflector converges light from 0 degree to 45 degree, however, it does not completely converge light beyond an angle of 45 degree so that a small cup is needed to converge light and increase the uniformity. In order to achieve shadow-free illumination, a multi-level reflector has been used. Total size of the LED dental lamp is 107 × 114 × 67 mm3.
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