The invention relates to a two-slit interference fringe decoding spectrum
confocal displacement sensor and a displacement measurement method thereof. A
grating spectrometer is used in a spectrum analyzing unit of a
current spectrum confocal displacement sensor, the beam split principle is complex, cost is high, detected
wavelength can drift along with time and environment, and the measuring accuracy of the sensor is affected. The sensor comprises a
broadband point light source, a non-aberration spectroscope, a dispersing lens group, a
confocal pinhole, a non-aberration collimating lens, an interference two-slit screen, an adaptive lens, a rectangular diaphragm and a
linear array CCD. Reflected light of the surface of a measured object is subjected to filtering through the confocal pinhole, then quasi-monochromatic light is formed, after non-aberration collimating, the quasi-monochromatic light is divided into two sub column face light sources by two slits, interference is formed, the widths of the interference fringes and the
wavelength of the reflected light of the surface of the measured object are in good
linear relation, and by interpreting the widths of the interference fringes, measuring of object displacement is achieved. The displacement sensor and the method have the advantages of being low in cost, good in
linearity and high in resolution ratio, and meanwhile an instrument is simple in structure and easy to
machine.