Optics: measuring and testing – By light interference – For dimensional measurement
Reexamination Certificate
2005-12-13
2005-12-13
Lee, Hwa (Andrew) (Department: 2877)
Optics: measuring and testing
By light interference
For dimensional measurement
Reexamination Certificate
active
06975406
ABSTRACT:
A method and apparatus used to reduce glitches in measurements made by an accumulation of phase changes over a range greater than 2π. Embodiments of the invention feature the use of a glitch filter that receives a phase input indicating a position value. The glitch filter reduces glitches by using a feedback term that has been reduced modulo 2π.The method includes measuring a plurality of values of a measurement signal, determining a current position value based on each of the plurality of measured values, wherein determining includes determining a delta value based on a current measured value and a previous position value, wherein the delta value is reduced modulo 2π to a range of ±π, and determining the current position value based on the determined delta value, and outputting at least one of the determined current position value and a velocity value.
REFERENCES:
patent: 3961138 (1976-06-01), Fellinger
patent: 4083229 (1978-04-01), Anway
patent: 4688940 (1987-08-01), Sommargren et al.
patent: 5200982 (1993-04-01), Weeber
patent: 5249030 (1993-09-01), Field et al.
patent: 5471303 (1995-11-01), Ai et al.
patent: 5530542 (1996-06-01), Kalem et al.
patent: 5608523 (1997-03-01), Kalem et al.
patent: 5767972 (1998-06-01), Demarest
patent: 5835199 (1998-11-01), Phillips et al.
patent: 6072581 (2000-06-01), Stephenson et al.
patent: 6218870 (2001-04-01), Wilson
patent: 6219144 (2001-04-01), Hill et al.
patent: 6424407 (2002-07-01), Kinrot et al.
patent: 6456380 (2002-09-01), Naganuma
patent: 6597459 (2003-07-01), Demarest
patent: 2003/0112444 (2003-06-01), Yang et al.
patent: 0 974 868 (2000-01-01), None
patent: WO98/20623 (1998-05-01), None
F. Demarest, “High-resolution, high-speed, low data age uncertainty, heterodyne displacement measuring interferometer electronics”, pp. 1024-1030 (Meas. Sci. Technol. 9, Apr. 3, 1998).
N. Bobroff, “Recent advances in displacement measuring interferometry”, pp. 907-926 (Meas. Sci. Technol. 4. 1993), no month available.
Oka, K., Tsukada, M. and Ohtsuka, Y., “Real-time phase demodulator for optical heterodyne detection processes”,Meas. Sci. Technol. 2, 106-110 (1991).
Oldham, N.M., Kramar, J.A., Hetrick et al., “Electronic limitations in phase meters for heterodyne interferometry”,Precision Eng. 15, 173-179 (1993).
Fish & Richardson P.C.
Lee Hwa (Andrew)
Zygo Corporation
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