Three wavelength optical measurement apparatus and method

Details Three wavelength optical measurement apparatus and method Three wavelength optical measurement apparatus and method

1991-03-27

1992-10-06

Turner, Samuel A.

Optics: measuring and testing

By particle light scattering

With photocell detection

356357, 356355, 356360, G01B 902

Patent

active

051536692

ABSTRACT:
Optical metrology method and apparatus wherein three optical wavelengths are generated and separated into a reference beam (RB) and an object beam (OB) having substantially equal optical path lengths. After reflecting from a surface being measured OB is combined with RB and provided to sensors which measure the intensity associated with each of the wavelengths. Any difference between the intensities is indicative of a difference in the optical path lengths of OB and RB and is a function of the polarization state of each of the three returned wavelengths. Differences in optical path length are shown to be indicative of a displacement of the object being measured. Preferably, two multimode laser diodes (12,14) are provided for generating the three optical wavelengths. Two synthetic wavelengths are derived from the three optical wavelengths and are employed to improve the precision of measurement while retaining a large dynamic range made possible by the use of a large synthetic wavelength.

REFERENCES:
patent: 4886362 (1989-12-01), Oono

Affiliated with

Also associated with

Rating

Three wavelength optical measurement apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Three wavelength optical measurement apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three wavelength optical measurement apparatus and method will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1193473