| The spectrometer is an important part of optical instruments. It is basic equipment applying the optical principle for measuring, analyzing and processing the material structure and components. It has the advantages of high precision, large measuring range, fast speed. But the ordinary spectrometer can only detect the wavelength of 400-800nm, and in some special fields, we need detect the UV band whose wavelength is 200-400nm. In the present, many UV spectrometers on the market are using backside thinning or coated CCD as the photosensitive element, so the price is relatively expensive. This paper proposes a design scheme of using the CMOS sensor chip S11639 as the photosensitive element. The design scheme uses fiber for guiding light, and grating for dispersing light. Then the treated light is parallel projected on the surface of the S11639. And the light signal will be converted to electrical signal. Then the data will be uploaded to the PC from USB port for data acquisition and analysis.In this design, in order to make the S11639 sensor to get the parallel beam, an optical system with reasonable structure is needed. This paper adopts the asymmetry Czerny-Turner optical system which can greatly eliminate the aberration by optimizing the optical path. The optical signal is transformed into an electrical signal by S11639. Then the signal will be converted into a digital signal by the high precision A/D converter. Because the output signal data is quite huge, so it will be stored in external RAM temporarily, and then the CPLD (complex programmable logic device) will control the various parts to cooperate with each other to transfer the signal. At last, the data will be uploaded to PC from USB port for data acquisition and analysis, the validity of this design scheme of the compact UV-VIS optical spectroscopy is proved through the designed experiment contrasts. The results show that it has good sensitivity to UV light. Its spectral range is 200nm-900nm and its resolution up to 1.5nm. |
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