| In the traditional UV spectrophotometers PMTs are used as the receiver, and a wavelength scanning structure is used to realize wavelength scanning. This kind of spectrophotometer features complex structure, large volume and long scanning time, they can't realize multi-wavelengths measurement simultaneously, can't be used for field works and can only be used in the laboratory.In this paper, a method on how to design a multi channel and concave grating UV spectrophotometer is introduced. According to this method, a new kind of UV Spectrophotometer is developed successfully. Compared with the traditional spectrophotometers, this new one has the following characteristics: 1. A multi-channel detector is used as the receiver, a flat field holographic concave grating as the dispersing element and a touch screen as the output and input device. It can realize rapid scanning, in the spectral range from 200nm to 800nm.2. All of the components in the spectrophotometer are fixed, there are not any moving parts, therefore the wavelength repeated error is "zero".3. Rapid scanning takes only 10ms to get a spectrum.4. Its volume is only 190×170×100mm3, much smaller than the traditional one.It can realize multi wavelengths measurement simultaneously.It can be used for on-line and field works. As the development, the following works are finished: 1. Design of a small dispersing system in which there are only two components: a multi channel detector and a flat field holographic concave grating. Its volume is only 100×100×50mm3. 2. Design of a new kind of driving and sampling system for multi channel detector, in this new driving system, highly integrated single chip processor C8051F020 is used as the microprocessor generating the pulse to drive the multi channel detector, the output signal from the multi channel detector is amplified by the amplifier in the microprocessor, then is converted to digital value by the AD converter inside the microprocessor, the AD results are stored in the on chip RAM. The AD results can be transmitted to computer or main microprocessor by the series port. This new driving circuit features less electronic components, high integration and simple tuning. 3. Design of the driving circuit for touch screen, the circuit uses touch screen control chip ADS7843 to control the touch screen. 4. Design of spectral processing software based on C++ builder 6.0. It has the functions such as communicating with the lower micro processor, display, print and calculate the spectrum.The design and development of the new spectrophotometer is supported by the national item of "The tenth five years plan" for scientific instruments, the most of researching and developing works are finished in the Beijing Purkinje General Instruments Ltd. Some fabricated prototypes are finished by the company and passed by the acceptance organized by the National Ministry of Science and Technique. In this paper, the following innovative ideas are presented: 1. Design of a fully integrated portable spectrophotometer, this new one includes all parts needed in it, it is the first one in China, some similar foreign company's products don't integrate lamp. Design of a dispersing system based on a multi channel detector and a flat field holographic concave grating. There are not any moving parts in it, therefore the wavelength repeated error is "zero", its volume is only 100×100×50mm3.Realizing the rapid scanning in the UV range at first in China, the fastest speed is 10ms for getting a spectrum.Design of a driving and sampling circuit for multi channel detector using a high intergrated C8051F020 as the processor, this circuit features high integration and easy tuning.For the first time, touch screen is used as the input and output device in the spectrophotometer.
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