Optical lens for correcting astigmatism
US5016977A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 1990 |
| Grant date | May 21, 1991 |
| Priority date | — |
| Expiry date | Feb 5, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C2202/20
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention relates to an optical lens for correcting astigmatism. It includes diffractive components whose outlines are delimited by conic section curves having non-degenerate centers. More precisely, in accordance with the invention, the lens includes adjacent diffractive components having hyperbolic or elliptical outlines with a periodicity in r.sup.2 in two mutually orthogonal directions x and y intersecting on the axis of the lens and coinciding with the main axes of the hyperbolas or of the ellipses, which are determined respectively by the equations: .DELTA.r.sub.x.sup.2 =2.lambda..vertline.f.sub.x .vertline.; and .DELTA.r.sub.y.sup.2 =2.lambda..vertline.f.sub.y .vertline.; in which: .DELTA.r.sub.x.sup.2 represents the periodicity in r.sup.2 along the x direction; .DELTA.r.sub.y.sup.2 represents the periodicity in r.sup.2 along the y direction; .lambda. represents the mean utilization wavelength; f.sub.x represents the desired focal length in the X direction; and f.sub.y represents the desired focal length in the Y direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.