ENCODER, OPTICAL DEVICE, EXPOSURE DEVICE, EXPOSURE METHOD, AND METHOD OF MANUFACTURING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a compact encoder in which utilization efficiency of the amount of diffraction light reflected and diffracted on a grating is high as compared with prior art.

SOLUTION: An encoder head 20 comprises a first corner cube 21 which reflects +1st order diffraction light, produced when a scale 5 (grating) is irradiated with illumination light from a light source and the illumination light is reflected and diffracted on the scale 5, to impinge on the scale 5 again at an angle equal to the diffraction angle of the +1st order diffraction light, and a second corner cube 23 which reflects -1st order diffraction light reflected and diffracted on the scale 5 to impinge on the scale 5 again at an angle equal to the diffraction angle of the -1st order diffraction light.

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