Browse Prior Art Database

Non-Contact Interferometric Technique of Measuring the Centering Accuracy of Cylindrical Lens

IP.com Disclosure Number: IPCOM000061523D
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 128K

Publishing Venue

IBM

Related People

Arnold, RC: AUTHOR

Abstract

Mechanical methods for measuring centering accuracy used today, such as gauge fittings and test plates, are undesirable because of the highly polished and usually coated surfaces of today's lenses. This non-contact, double-pass interferometric technique will accurately measure the center of curvature without damaging the lens. A gauge fitting or a test plate fitting are methods used in fabricating the lens in an optical shop, during the lapping, grinding, and polishing steps. However, to measure a completed lens today, a non- contact method is mandatory because of the highly polished surfaces and the coatings. The contact methods can damage the surface or a portion of a surface (pinhole-slit effect). A non-contact technique of measurement cannot damage the lens.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 2

Non-Contact Interferometric Technique of Measuring the Centering Accuracy of Cylindrical Lens

Mechanical methods for measuring centering accuracy used today, such as gauge fittings and test plates, are undesirable because of the highly polished and usually coated surfaces of today's lenses. This non-contact, double-pass interferometric technique will accurately measure the center of curvature without damaging the lens. A gauge fitting or a test plate fitting are methods used in fabricating the lens in an optical shop, during the lapping, grinding, and polishing steps. However, to measure a completed lens today, a non- contact method is mandatory because of the highly polished surfaces and the coatings. The contact methods can damage the surface or a portion of a surface (pinhole-slit effect). A non-contact technique of measurement cannot damage the lens. In an optical system the optical axis is determined by the center of curvature of each radius on every element. This optical axis is defined as a straight line passing through the center of the source and the center of the detector. All elements of an optical system are arranged with the center upon and with principle plane normal to the optical axis. The mechanical axis of a lens is that continuous straight line in space perpendicular to the plane of the flange or locating surface of the lens mounts and passing through the center of symmetry of the flange or locating surface. The term centering is defined as the act of causing the mechanical and optical centers of a lens to coincide. The methodology of non-contact measurement of centering accuracy of highly transmissive cylindrical lenses is the subject of this article. In the experiment which developed these methods, a double-pass interferometer was used. The measurement beam in a double- pass-type interferometer, transverses the lens under test once and is then reflected back through the lens under test a secon...