A set of inclination measurement-based high-resolution liquid-level laser detecting system is developed to detect the liquid-level of stereolithography apparatus
where a brightness-variable laser source is adopted to remove the computational error of divider
and a closed-loop circuit is set to measure the terminal voltage directly proportional to the output current of position sensitive device and hence the position of laser beam can be accurately indicated. An AC-modulated laser enables to separate background light and dark current to effectively eliminate the influence of stray light and dark current on the detection accuracy. By means of the precision calibration of detecting system
the resolution of this system can reach to 1.5 μm in the liquid-level varying range of 1-7 mm.
WANG Xiaodong, ZHAO Jie, CAI Hegao. The design of non-contact laser range finder by using PSD and its performance analysis [J]. Journal of Harbin Institute of Technology, 1996,28(4):100-104.
WANG Guangzhi, DING Haishu, DING Hui. Light disturbance to position sensitive detectors:pattern and methods to overcome [J]. Journal of Tsinghua University, 1997, 37(1):61-64.
LIU Ganfeng, XIE Feng, LOU Wei, et al. An automatic fitting method of the sensor's characteristic curve [J]. Control and Instruments in Chemical Industry, 2002,29(4):45-47.