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.