公开(公告)号：EP0760932A1

公开(公告)日：1997-03-12

申请号：EP95922098.0

申请日：1995-05-25

申请人： MICROE, INC.

发明人： MITCHELL, Donald, K. ,  THORBURN, William, G.

IPC分类号： G01B11 ,  G01D5

CPC分类号： G01D5/38

摘要： The apparatus disclosed herein employs a grating (13) which concentrates light at preselected wavelength into the positive (33) and negative (35) first orders while minimizing the zeroth order (31). The grating (13) is illuminated with monochromatic light (15) of the selected wavelength and a poly-phase periodic detector (25) has its sensing plane spaced from the grating a distance less than W/2tanυ where υ = arcsin (μ/P), where W is the width of the illuminated region of the grating. The period of the poly-phase detector is equal to P/2 so that each detector element (51) or phase responds principally to the natural interference (37) between the positive redirection of the diffracted light. Preferably, the distance of the sensing plane from the grating (13) is greater than W/2tanζ where ζ = arcsin (3μ/P) so that the detector response does not include substantial components from diffraction orders higher than the first.

公开(公告)号：EP0760932B1

公开(公告)日：2003-02-26

申请号：EP95922098.9

申请日：1995-05-25

申请人： MICROE, INC.

发明人： MITCHELL, Donald, K. ,  THORBURN, William, G.

IPC分类号： G01B9/02 ,  G01D5/38

CPC分类号： G01D5/38