Displacement measuring device based on position-sensitive detector and application method of displacement measuring device

Abstract

The invention provides a displacement measuring device based on a position-sensitive detector and an application method of the displacement measuring device. The position-sensitive detector adopted in the invention is a two-dimensional PSD (phase-sensitive detector); a signal processing module in the existing displacement measurement device based on the position-sensitive detector is improved in a focused manner, and adaptability improvement is performed for a signal pre-processing module, so as to ensure that a phase method can be applied in the method for processing digital signals. The application method comprises steps of: performing multiple beam modulation, signal pre-process and transformation, subsequent digital process and transformation and the like for applying the phase method; and calculating the phase information corresponding to various frequency signals by utilizing an FFT (fast Fourier transformation) algorithm, further processing the various phase information to obtain the displacement information of a plurality of light spots on a PSD photosensitive surface, thereby realizing the precise measurement for the light spot positions of a plurality of beams. The device and the method provided by the invention have the characteristics of high precision, good flexibility, stable system, simple signal processing circuit, low cost and the like.

Description

technical field [0001] The invention relates to a displacement measuring device and its application, in particular to a displacement measuring device based on a position sensitive detector and its application. Background technique [0002] Position Sensitive Detector (PSD for short) is a semiconductor optoelectronic device that is sensitive to the center of gravity of the incident light spot. It has high position resolution, fast response speed, wide spectral response range, high reliability, and relatively simple processing circuit. It has been widely used in the detection of position, displacement, distance, angle and related quantities. The displacement measurement device based on the position sensitive detector is composed of four parts, which are PSD, semiconductor laser source, electronic processing unit and bracket for fixing the relative position of PSD and semiconductor laser source. Among them, PSD is divided into one-dimensional and two-dimensional. One-dimensio...

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Problems solved by technology

[0005] It can be seen from the above formula that because the amplitude method processes the output signal amplitude, it is very sensitive to noise signals, so it has the disadvantages of being sensitive to background light, poor anti-interference ability, and high requirements for light sources.

Since in the method of digital signal processing, the calculation method adopts the amplitude method to bring so many deficiencies, why not use other calculation methods? The reason is that the existing displacement measurement devices based on position-sensitive detectors are only suitable for the amplitude method

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