The present invention relates to a high-accuracy wide-range double-layer nano-
grating micro displacement detection device. The micro displacement detection device includes a displacement sensing module, a
processing unit and a display unit; the displacement sensing module is connected with the display unit through the
processing unit; the displacement sensing module comprises double nano-
grating layers which can move relative to each other; the double nano-
grating layers include a movable nano-grating array and fixed nano-gratings; a plurality of nano-grating regions are spliced to form the movable nano-grating array; certain intervals are left between the plurality of nano-grating regions; the
processing unit includes a subdividing circuit; and the subdividing circuit can improve the resolution of the output signals of a
photodetector array. The grating period of the micro displacement detection device is smaller than the grating period of an existing
micrometer-scale device, and therefore, the micro-displacement detection precision of the gratings is improved; the grating regions of the movable nano-grating array are spliced, so that the range of the micro displacement detection device is wider. The micro displacement detection device has the advantages of compact overall structure, high
miniaturization degree and higher practicality.