| Summary: | 碩士 === 國立清華大學 === 光電工程研究所 === 97 === 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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