Toroidal lens for sunglasses
US4867550A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 1, 1988 |
| Grant date | Sep 19, 1989 |
| Priority date | — |
| Expiry date | Feb 1, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02C7/10
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is a toroidal lens for use in a pair of sunglasses, comprising a unitary pane of transparent material which is curved about each of two substantially perpendicular axes, each having a substantially constant radius such that the lens defines a portion of the surface of a toroid. A cross-section taken along the horizontal axis of the lens reveals an arcuate configuration which may be characterized as having a rfadius R.sub.1. A cross-section taken along a vertical axis reveals an arcuate configuration through the lens having a radius designated R.sub.2. Optimally, R.sub.2 .gtoreq.1.10 R.sub.1, and the length of the lens along the horizontal arcuate cross-section is in the range of from about 51/2 inches to about 7 inches. The lens may have either a uniform thickness throughout, or may taper from a greater thickness in a region centered about the midpoint, generally above the nose of a wearer, to a lesser thickness near the peripheral ends of the lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.