Research On The Aiming Signal Processing Of The Optical Probe Measurement System

Surface metrology is an important field of geometry metrology. With the rapid development of such technologies as miniaturized machining, micro-optical, micro-electronics and micro-mechanics, the 3-D measurement of many specimens require high accuracy. As well as the request of the measurement accuracy for the large size object is much higher. How to measure the 3-D surface topography of specimens quickly and accurately has become a challenge in field of modern micro-measurement.This research on aiming signals measuring and processing system is based on the project"Multi-Probe Topography Measurement System". Based on the differential confocal microscopy technology, the project is to develop a surface measurement technique with high accuracy, resolving power and non-contact mode. Moreover, the aiming probe as the device for signals collection plays an important part in the high accuracy topography measurement system.Firstly, this paper explains the measurement principle of differential confocal optical probe measurement system particularly, and analyses the loss of the light intensity of the light beam through the optical devices. It also brings out the light signal take-over and transformation circuit design, and the electricity signal processing method.It describes the design of the aiming signals measuring and processing, especially the characteristic of the electrophotonic detector and its preamplifier, which is used for I-V transformation. Afterwards, it shows the variable gain amplifier, the low-pass filter, the subtracter, adder and comparator design in detail, introducing the knowledge about the data acquisition, the software program of the data acquisition.Finally, every part of the system is tested by simulative experiments. It proves that all the parts are available for the optical probe measurement system.