Patent attributes
Ophthalmic lenses and methods for their design and use involve displacement functions based on the sum of a continuous cosine function and a continuous sine function, optionally over a plurality of echelettes. Exemplary monofocal and multifocal diffractive ophthalmic lenses provide reduced light scatter and/or improved light energy distribution properties. Such properties can be provided by diffractive profiles, often having subtlety shaped echelettes with appropriately curving profiles. Light scatter may be generated by the sharp corners associated with vertical steps between adjacent conventional diffractive echelettes. Smooth diffractive profiles of the invention reduce light scatter. Light energy directed toward non-viewing diffractive orders may have a unwanted effects on vision quality. Diffractive profiles as described herein may limit the light energy in certain, selected orders, thereby improving viewing quality and mitigating unwanted effects such as dysphotopsia. Diffractive profiles may also vary the light energy distributed between individual echelettes, providing additional advantages in various viewing situations.
