led | 量子荧光|微型光纤光谱仪-ag贵宾会

there is a need in many resource limited countries and laboratories for a low cost analytical instrument that could provide both qualitative and quantitative chemical information. there are also great needs for low cost autonomous instruments that could help monitor the fragile environment around the world on a global scale.1,2with the advances in modern electronics, microcontrollers could provide great capabilities to acquire and process sensor signals. the development of compound semiconductor manufacturing technology could also produce many leds with wavelengths from ir down to the 365 nm uv range. with its compact size, a wide range of selections of available wavelengths and low power consumption, leds are used extensively in analytical instruments as light sources.3-15 dasgupta et. al. gave a very detailed review for led application in flow injection analyses.3,4 led light sources for sensor applications were also extensively reviewed by kostov et al.5-7 hauser et al.8-10 built a multi-wavelength spectrometer to analyze aluminum, copper, ammonia, calcium, phosphate, chromium, and nitrile. in his work, leds with seven wavelengths and a 2*7 fiber optic coupler were used to construct a multi-wavelength spectrometer. the 2 *7 fiber optic coupler would greatly increase the cost of the spectrometer and would not be suitable for large scale employment. hamilton et al.11 built a four color led photometer with a material cost of about us$ 200. the led photometer was designed with analog circuits and thus was not very flexible or user configurable. knagge et al.12 built a spectrometer with a mini light bulb, diffraction grating and lego block. the material cost was also about us$ 200. this spectrometer was not robust or inexpensive enough for large scale deployment in the field. cantrell et al.13 designed a slim spectrometer with red, yellow, and blue leds. the total cost to construct the slim spectrometer is about us$ 25. a tsl230 programmable light-to-frequency converter from texas advanced optoelectronic solutions (taos) was used as photo-detector for the slim spectrometer. the slim spectrometer is low cost, low power consumption and robust, thus it is very suitable for autonomous instruments employed in the field. the only limitation is the available wavelength in the slim spectrometer.

自有人类文明以来，照明在我们的生活中是那么重要，没有灯光的夜晚整个世界将充斥着黑暗。茫茫大海中的灯塔是航行船只的向导，它指示着礁石，浅滩，港口，尽管后来出现了gps等电子导航定位系统，但仍无法取代灯塔在船员们心中的地位。led是发光二极管的简称，英文全称是light emitting diode。led照明是继鹤丝灯、突光灯、气体放电灯之后的第四代照明产品⑴。

发光二极管(1ight emitting diode，led)是一种利用半导体pn结把电能转换成为光能的光电转换器件，它和白炽灯等其他照明光源相比较，具有体积小、寿命长、功耗低、安全节能等优点，已经成为照明产业新的增长点和发展方向¨l ]。