The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 26, 1990
Filed:
Aug. 08, 1989
John A Futhey, Petaluma, CA (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A diffractive lens has a plurality of diffractive zones at least one of which has an optical step having an optical height equal to j.lambda. and at least one of which has an optical step having an optical height equal to k.lambda. where .lambda. is a design wavelength of the lens and j and k are unequal nonzero integers. Alternatively stated at least one of the optical steps induces a relative phase shift of 2j.pi. at the back conjugate point between two light rays emerging from a point source at the front conjugate point and striking the lens immediately on opposite sides of the step and at least one of the steps induces a relative phase shift of 2k.pi. at the back conjugate point between two light rays emerging from a point source at the front conjugate point and striking the lens immediately on opposite sides of that step.