公开(公告)号：EP1729097A4

公开(公告)日：2008-02-27

申请号：EP05721111

申请日：2005-03-18

申请人： MITUTOYO CORP

发明人： SHIMOMURA TOSHITAKA ,  NIHOMMORI SHINGO ,  MIZUTANI MIYAKO ,  ALTENDORF ERIC HERBERT ,  TOBIASON JOSEPH DANIEL

IPC分类号： G01D5/36 ,  G01D5/347 ,  G02B13/22

CPC分类号： G01D5/38 ,  G01D5/00 ,  G01D5/34715 ,  G01D5/36

摘要： A photoelectric encoder has a telecentric optical system in which a first lens and an aperture located at a focal position of the first lens are interposed between a main scale and a photoreceptor. At least a second lens is interposed between the aperture and the photoreceptor with a focus of the second lens on the aperture, thereby constituting a bilateral telecentric optical system. This makes it possible to improve the signal detection efficiency and increase the assembly tolerance.