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The Designof High Stable Current Sourceand Temperature Controller For Semiconductor Laser Diode

Posted on:2016-06-12Degree:MasterType:Thesis
Country:ChinaCandidate:L W MengFull Text:PDF
GTID:2348330479954679Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
Laser speckle imaging contrast analysis is a non-contact, wide field and fast two-dimensional blood flow detection technology, which is widely concerned in the field of biomedicine in recent years. Semiconductor laser has the advantages of small size, high efficiency, long life, easy to control, etc., and it is used as the light source of laser speckle blood flow imaging instrument. However, when the injection current and the working temperature of the laserdiode changed,the output optical power, the central wavelength and the spectrum characteristics of the laserdiode will change accordingly. For laser speckle imaging, the change of the wavelength and spectrum characteristics of the light source can affect the blood flow detection. In this paper, for the specific requirements of laser speckle blood flow imaging, a high stability of constant current, constant temperature control system was designed and developed. The main content is listed as follows:(1) Developed a set of high precision constant current source circuit, realized 100 mA operating current under long time,the stability is better than 4 ?A. And developed electrostatic protection, delay start-off andover voltage protection diode laser protection circuit.Developed theelectrical isolation circuit to avoid external interference to ensure constant current source circuit and the accuracy and stability.(2) Developed a constant temperature control system of laserdiodebased on thermoelectric cooler, the system includes the temperature collection circuit, feedback circuit and PID temperature controller. The requirement of the working temperature of 25? was realized, the fluctuation oftarget temperature for a long time is less than ±0. 006?.(3)In this paper, the system for laser speckle imaging instrumentwith the high Stable CurrentSourceandTemperatureControllerforlaserdiode driver was tested.The results showed that the static contrast fluctuation was less than 0. 4% in 15 minutes.
Keywords/Search Tags:Laser diodePrecision, constant current, source, Temperature control, PID controller
PDF Full Text Request
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