Invention Grant
- Patent Title: Two axis encoder head assembly
- Patent Title (中): 双轴编码器头组件
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Application No.: US13796316Application Date: 2013-03-12
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Publication No.: US09243896B2Publication Date: 2016-01-26
- Inventor: Eric Peter Goodwin
- Applicant: NIKON CORPORATION
- Applicant Address: JP
- Assignee: Nikon Corporation
- Current Assignee: Nikon Corporation
- Current Assignee Address: JP
- Agency: Roeder & Broder LLP
- Agent Steven G. Roeder
- Main IPC: G03B27/54
- IPC: G03B27/54 ; G03B27/52 ; G01B11/14 ; G03F7/20
Abstract:
A measurement system for measuring the position of a work piece (28) includes a stage grating (234) and an encoder head (236). A first measurement beam (38A) is directed at the stage grating (234) at a first angle, the first measurement beam (38A) being at a first wavelength. A second measurement beam (38B) is directed at the stage grating (234) at a second angle that is different than the first angle, the second measurement beam (38B) being at a second wavelength that is different than the first wavelength. At least a portion of the first measurement beam (38A) and at least a portion of the second measurement beam (38B) are interfered with one another to create a measurement signal along a signal axis.
Public/Granted literature
- US20140049762A1 TWO AXIS ENCODER HEAD ASSEMBLY Public/Granted day:2014-02-20
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