Complete digitisation 4 quadrant detector detecting laser beam deflection angle device and method

Abstract

The invention relates to a device and a method of the detection of a laser-beam deflection angle by a full digital four quadrant detector, and comprises a preposed amplifying electric circuit (12), a filtering electric circuit(13), an AD switching electric circuit(16), an offset display module(18), a four quadrant detector(1), a secondary amplifying electric circuit module(14), a variable gain amplifying electric circuit module(15) and a high speed micro processor module(17). The invention solves the problem of reduced measurement precision by using a full digital processing method; the model adopts the auto adaptation and the variable gain amplifying electric circuit to maintain the strength of signals entering an AD collecting unit by the automatic variation of the gain according to strengths of input signals; the model overcomes a reduced resolving precision caused by a reduced signal to noise ratio resulting from the variation of input light intensity. The invention overcomes the defect of a slow resolving speed caused by using a single chip for resolving by using the high speed micro processor to resolve the beam reflection angles.

Description

Technical field [0001] The invention belongs to the field of photoelectric measurement technology, and is a device and method for detecting the deflection angle of a laser beam with a fully digital four-quadrant detector. Background technique [0002] At present, the photodetectors mainly used to measure the deflection angle of laser beams include charge-coupled devices (CCD), position sensors (PSD) and four-quadrant detectors (QD). Although the data output by the charge-coupled device (CCD) can directly reflect the position of the light spot on the photosensitive surface, the deflection angle of the laser beam (relative to the optical axis) can be obtained according to its offset from the center of the photosensitive surface, but the charge-coupled device (CCD) The device (CCD) has too many pixels, and the amount of data to be processed is too large, which is not suitable for the measurement of the laser beam deflection angle with high dynamic range; while the position sensor (P...

AI Technical Summary

Problems solved by technology

Because it uses a sum-difference circuit, it will cause crosstalk between the four-way signals of the four-quadrant detector and introduce additional common-mode noise, and it is not convenient to compensate the unbalanced performance between channels through software, reducing the resolution accuracy ; Because it uses a single-chip microcomputer, its calculation accuracy and calculation speed are limited. In this system, the fastest speed is 90 times / S

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