Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
2006-11-07
2006-11-07
Luu, Thanh X. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C250S231140, C356S617000, C341S013000
Reexamination Certificate
active
07132647
ABSTRACT:
A main scale of an optical displacement measuring apparatus has slits arranged on it at regular intervals, a part of which is a missing slit that does not allow light to pass through used for detecting the original point. An index scale has four sets of windows formed on it. The four windows are arranged with mutual phase differences of ¼ P, where P is the pitch of the arrangement of the slits. When a part of the missing slit overlaps with the index scale, no light reaches to photodiodes from the missing slit and only a partial light flux passes through a window, so that the light quantity decreases. An original point signal associated with the missing slit can be obtained by adding up the outputs of all the photodiodes.
REFERENCES:
patent: 4263506 (1981-04-01), Epstein
patent: 5279044 (1994-01-01), Bremer
patent: 5774074 (1998-06-01), Cooper et al.
patent: 6043483 (2000-03-01), Schreiber
patent: 6198534 (2001-03-01), Hofer et al.
patent: 6342697 (2002-01-01), Nagai et al.
patent: 6392224 (2002-05-01), Holzapfel et al.
patent: 6472658 (2002-10-01), Mayer et al.
patent: 6713756 (2004-03-01), Yamamoto et al.
patent: 6800842 (2004-10-01), Ito
patent: 1 154 242 (2001-11-01), None
patent: 6-56304 (1994-07-01), None
patent: 2002048602 (2002-02-01), None
patent: 2002-323347 (2002-11-01), None
patent: 2003-161645 (2003-06-01), None
European Patent Office Search Report (counterpart EP application 05004593), dated Jul. 15, 2005.
Atsuta Akio
Igaki Masahiko
Canon Kabushiki Kaisha
Luu Thanh X.
Morgan & Finnegan L.L.P.
Yam Stephen
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