Pilkington Pe Limited

Pilkington Diffractive Lenses Limited

Pilkington Barnes Hind, Inc.

Pilkington Visioncare Holdings, Inc.

Optics and Vision Limited

Michael H Freeman

Colin M Perrott

William E Meyers

Multifocal contact lens

Optical systems, telescopes and binoculars

A method of fitting rigid gas permeable contact lenses comprising the steps of:

Rigid gas permeable lenses

A consumable laser mask for forming a visual lens, especially a contact lens, in which at least a portion of the light passing through the lens is focussed by diffractive means. The laser mask is shaped to provide the diffractive means in the finished lens, and is made from a polymeric material with a thickness such that no residue is left at the completion of the laser ablation process. The invention also includes a method of manufacturing a lens using a consumable laser mask in accordance with the present invention.

Manufacture of visual lenses

A method of correcting or alleviating presbyopia in humans comprising (a) fitting a first contact lens to a first eye, and (b) fitting a second contact lens to the other eye. Each of the lenses has a first power provided by the shape, curvature and material of the lens to provide a refractive corrected image and a second power provided by diffractive means to provide a second corrected image, the second power being additive to (or subtracted from) the first power. The lenses are fitted so that one has a refractive near image optical power and the other has a refractive distance image optical power, and the diffractive means of the lenses are arranged so that the amount of the light directed into the near image by one lens is substantially greater than that directed into the far image by that lens, and the amount of light directed into the far image by the other lens is substantially greater than that directed into the near image by that other lens. In this way the wearer sees an image of relatively high intensity and retains a large amount of stereoscopic vision.

Method and contact lenses for treating presbyopia

An artificial eye lens such as a contact lens or intra-ocular lens corrects astigmatism by two sets of substantially linear parallel zones arranged to diffract light predominantly into one order at one orientation, the spacing of the zones diminishing on either side of the linear axis. In addition circular diffraction zones may be provided to give both spherical and cylindrical power for astigmatism correction.

Diffractive ophthalmic lens for correcting astigmatism

A contact or spectacle or implant lens has positive diffractive power which introduces negative longitudinal chromatic aberration that more than counteracts, and is preferably greater than twice, the natural positive longitudinal chromatic aberration of the eye. The residual negative longitudinal chromatic aberration enables the eye/brain system to perform tasks by concentrating on the appropriate color component at the different respective distances without need to accommodate.

Ophthalmic lenses with diffractive power

A contact lens has a transmission hologram which provides diffractive power on a wavelength and/or amplitude selective basis whereby light from near and distant objects can be focussed on the retina of a presbyopic wearer. Similarly an implant lens can have a transmission hologram to correct for non-accommodative vision. The invention is particularly useful in providing an artificial eye lens with a bi-focal action without need for distinct near and far vision zones.

Artificial eye lenses

An ophthalmic lens incorporates a transmission hologram which has negative diffractive power and introduces positive longitudinal chromatic aberration to add to the natural longitudinal chromatic aberration of the human eye, thereby reducing the need to accommodate. The lens also has refractive power to balance the diffractive power or to give a desired overall or residual power.

Ophthalmic lens with diffractive power

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. The diffractive power arises from concentric zones, each providing an asymmetric retardation of light across the zone width to direct design wavelength light predominantly into a required order and sign of diffraction, while other wavelength light is predominantly transmitted at zero order. Design wavelength light from an object at one distance can then be focused by way of diffraction of that order and sign, and other wavelength light from an object at another distance can be focused by way of zero order transmission. Preferably the zones are defined, and the asymmetric retardation provided, by a rear surface contour having steps but which approximates to the required basic curvature.

Multifocal contact lenses utilizing diffraction and refraction

A system for biocular viewing of a distant scene or object especially under daylight conditions comprises an objective lens which produces an initial image, one or two relay lenses with associated reflectors which produce from that initial image a pair of tilted images, and a biocular magnifying eyepiece lens through which an observer views so that each eye receives light from a respective one of the tilted images. The system can be incorporated in a combined day and night viewing system employing common objective lens and eyepiece lens components for the day and night viewing paths.

Biocular viewing apparatus

Optical apparatus for biocular viewing which is small and of light weight comprises a solid optical element having a face which internally reflects light from an image surface to internally concave reflecting areas which reflect the light back to the face to emerge as two beams travelling towards respective eye positions via a corrector lens. The apparatus can be used in night vision goggles having a single image intensifier tube providing the image surface.

Optical apparatus

Optical apparatus, such as head-up display apparatus, for superimposing visual information on an observer's view of a scene or object comprises a substantially flat transmission hologram through which the observer views the scene or object, the hologram being disposed substantially orthogonally to and midway along an axis between the observer's eye position and projection optics so as to deviate light from an image produced by the projection optics to the observer's eye position with minimal field aberrations.

The invention provides a portable reader for reading, by way of a magnified image, microform material such as microfiche or microfilm. The reader has a support for the microform material and a light source to pass light through the material. A projection lens is provided to project an image of the material on to a screen and there is also a biocular magnifier lens through which an observer can view a magnified version of the image. A partial reflector is disposed in the light paths between the projection lens and the screen and between the screen and the biocular magnifier lens so that light travels from the projection lens to the screen via the partial reflector and from the screen to the biocular magnifier lens via the partial reflector. In a convenient arrangement light travelling from the projection lens is reflected by the partial reflector towards the screen, and light travelling from the screen is transmitted through the partial reflector to the biocular magnifier lens. On the other hand the arrangement may be reversed so that light from the projection lens is transmitted through the partial reflector to the screen while light from the screen is reflected by the partial reflector towards the biocular magnifier lens.

Growing community of inventors

Denbigh, United Kingdom

Michael H Freeman