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Patent

Phase shift multifocal zone plate

TLDR
In this article, a phase shift multifocal zone plate is designed to provide multiple focii with bright images, by adjusting the zone plate spacings such that some of the zone plates foci actually coincide with the multifocal Fresnel lens foci.
Abstract
A multifocal zone plate construction suitable for use in optical systems with multifocal requirements. It is designed as a phase shift multifocal zone plate to provide multiple focii with bright images. This is accomplished by adjusting the zone plate spacings such that some of the zone plate focii actually coincide with some of the multifocal Fresnel lens focii.

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Patent

Multifocal ophthalmic lens

TL;DR: In this article, a multifocal ophthalmic lens, having outer annular zones with vision correction powers less than the far vision correction power of the patient, was disclosed, and the net effect of the additional near vision annular zone and the additional annular node having power less than far vision power is to shift the best quality image from in front of the retina to an area on the retina of the eye, to thereby reduce halo effects and improve contrast.
Patent

Multi-focal diffractive ophthalmic lenses

TL;DR: In this paper, a lens according to the invention has diffractive power and two primary foci, where one focus is associated with the first diffractive order and one with the second order.
Patent

Optical element employing aspherical and binary grating optical surfaces

TL;DR: In this article, a negative meniscus optical element (107) and a positive power lens (112) are affixed to a common housing (124), which is removable from the telescope system.
Patent

Multifocal contact lenses utilizing diffraction and refraction

TL;DR: In this paper, a bifocal contact lens has diffractive power added to the basic refractive power provided by the material of the lens and the basic curvature of its front and rear surfaces to direct design wavelength light predominantly into a required order and sign of diffraction, while other wavelength light is predominantly transmitted at zero order.
Patent

Accommodating multifocal intraocular lens

TL;DR: Intraocular lenses include a lens body sized and adapted for placement in a mammalian eye and having a plurality of different optical powers, and a movement assembly joined to the lens body and adapted to cooperate with the mammalian eye to effect accommodating movement.
References
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Patent

Multiple focal length lens

Ruhle Hans