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:
Sep. 28, 2021
Filed:
Nov. 25, 2016
Itoh Optical Industrial Co., Ltd., Gamagori, JP;
Yasushi Miyajima, Gamagori, JP;
Itoh Optical Industrial Co., Ltd., Gamagori, JP;
Abstract
A corrective lens that can improve contrast sensitivity in a dark place, for example, at night is provided. When an axis in the anteroposterior direction passing through the geometric center of a lens is defined as the z-axis and a direction extending to the rear side of the lens is defined as the positive direction of the z-axis, a focal depth extension component represented by Ar(where r is the distance from the z-axis and A is a constant) is added to the z-coordinate value of a refractive surface determined based on a prescription power to increase the focal depth. The focal depth that decreases (shallows) in a dark place is increased to facilitate focusing on a target object located in front of or behind the original focal point. This can improve contrast sensitivity in a dark place.