A High-Speed, High-Accuracy Optical Position Sensor Integrated with an Analog and Digital Signal-Processing Circuit

This paper describes a high-speed and high-accuracy optical position sensor that detects the positions of multiple light spots illuminated by various types of light sources, such as a light-emitting diode and a laser diode. The applications using these systems usually require the measurement performance to be fast, of high accuracy, and capable of simultaneously detecting multiple points. The applications should also have some intelligence function, such as adaptation of the detection procedure to the environment being measured. We designed a new sensor system using an optical two-dimensional sensor array, an analog parallel scan circuit, and a neural network implemented on a field-programmable gate array (FPGA), which satisfied the above requirements. The experimental results with the prototype sensor system were as follows: (1) the relative error was at most 1.4%; (2) the sampling frequency was about 20 kHz; and (3) the sensor system reduced the influence of background light on the position detection by the neural network. (C) 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(12): 12-21, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10360