Patents by Inventor Amitava Gupta

Amitava Gupta has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5406341
    Abstract: A method for making a finished aspheric single vision, spherical or aspheric bifocal, multifocal or progressive addition contact lens includes the step of fitting a patient requiring a near correction with a single vision spherical or aspheric contact lens for optimal distance vision and comfortable fit. The patient is then over-refracted to determine the required near correction to be embodied in the contact lens. A portion of the optic corresponding to the center location of the pupil is marked on the convex side of the optic to form an optical preform. The optical preform is removed from the eye of the patient and the concave side of the optical preform is marked at a position corresponding to the mark on the convex side that denotes the center of the pupil. The mark disposed on the convex side of the optical preform is removed.
    Type: Grant
    Filed: November 23, 1992
    Date of Patent: April 11, 1995
    Assignee: Innotech, Inc.
    Inventors: Ronald D. Blum, Amitava Gupta
  • Patent number: 5319023
    Abstract: Optical lens bodies and haptics therefore are prepared from polymeric materials wherein all surfaces of the materials are substantially biologically inert to occular tissue, all surfaces are substantially free of surface defects when viewed through a 10 power optical microscope, the materials have a contact angle with water of at least 85.degree., a contact angle with glycerol of least 75.degree. and a surface energy less than 30 erg/cm.sup.2.
    Type: Grant
    Filed: June 26, 1992
    Date of Patent: June 7, 1994
    Assignee: Ioptex Research Inc.
    Inventor: Amitava Gupta
  • Patent number: 5316702
    Abstract: A method of casting an ophthalmic optic is described. A mold, an optical preform and a polymerizable resin are provided. The resin is disposed between the mold and the optical preform. The preform and the resin interact to produce a contact angle between the resin and preform of from about 20 degrees to about 45 degrees; or the mold and the resin interact to produce a contact angle between the mold and the resin of from about 45 to about 75 degrees; or both. The polymerizable resin is then cured.Another method of casting an ophthalmic optic is also described. A mold, an optical preform and a polymerizable resin are provided. The optical preform is supplied with a surface having a regular pattern of grooves that comprise a grid formed by intersecting curves or lines imprinted on the surface of the optical preform. The polymerizable resin is provided between the optical preform and the mold such that the polymerizable resin contacts the regular pattern of grooves on the optical preform.
    Type: Grant
    Filed: July 20, 1992
    Date of Patent: May 31, 1994
    Assignee: InnoTech, Inc.
    Inventors: Ronald D. Blum, Amitava Gupta, Steve Bennington
  • Patent number: 5274038
    Abstract: An optical lens of an acrylic polymer having an outermost surface modified in morphology to possess desired characteristics of low surface energy and high biological inertness. The modified surface is achieved by removing only molecular level irregularities in the outermost surface of an acrylic polymer optical lens body. The surface removal and smoothing process involves the steps of surface preparation and surface passivation. In surface preparation, the surface of the lens body is treated to render it wettable by a surface passivation reagent. In surface passivation, the surface prepared optical lens body is immersed in a surface passivation reagent which removes weakly bound water molecules from the outermost surface of the lens body and reorganizes or smoothes at the molecular level irregularities at the surface of the optical lens body.
    Type: Grant
    Filed: January 30, 1991
    Date of Patent: December 28, 1993
    Assignee: Ioptex Research Inc.
    Inventor: Amitava Gupta
  • Patent number: 5194456
    Abstract: The novel compound of the formula ##STR1## has been found to be useful as a UV absorber. A novel PMMA material has incorporated therein a UV absorbing amount of the novel UV absorber. Intraocular lenses and contact lenses are produced from PMMA having incorporated therein a UV absorbing amount of the novel UV absorber.Eyeglasses are produced having lenses of a polycarbonate material which has incorporated therein a UV absorbing amount of the novel UV absorbed.
    Type: Grant
    Filed: May 22, 1990
    Date of Patent: March 16, 1993
    Assignee: Ioptex Research, Inc.
    Inventor: Amitava Gupta
  • Patent number: 5141990
    Abstract: In-situ development of an ultraviolet absorber is provided by a compound such as a hydroxy-phenyl-triazole containing a group which protects the absorber during actinically activated polymerization by light at first frequency. After polymerization the protective group is removed by actinic reaction at a second frequency lower than the first frequency. The protective group is formed by replacing the hydrogen of the hydroxyl group with an acyl group containing 1 to 3 carbon atoms or an acryloxy group of the formula: ##STR1## where R.sup.1 is either an alkyl containing 1 to 6 carbon atoms or --CH.dbd.CH.sub.2.
    Type: Grant
    Filed: October 25, 1989
    Date of Patent: August 25, 1992
    Assignee: California Institute of Technology
    Inventors: Vincent B. McKoy, Amitava Gupta
  • Patent number: 5112351
    Abstract: A multifocal intraocular lens is produced which comprises a lens body having a plurality of optical zones which comprises an aspheric optical zone between each add and base power zone thereby providing a gradual transition in the curvature of the optic surface and avoiding abrupt changes in the curvature of the optic.
    Type: Grant
    Filed: October 12, 1990
    Date of Patent: May 12, 1992
    Assignee: Ioptex Research Inc.
    Inventors: Bruce Christie, Amitava Gupta
  • Patent number: 5106930
    Abstract: A contact lens material which is lipophobic, easily machined and is oxygen permeable which comprises a copolymer comprising from 25% to 50% by weight of a polysiloxanylalkyl ester of acrylic or methacrylic acid, from 40% to 69% by weight of a fluorinated styrene, from 4% to 7% of a hydrophilic monomer, from 2% to 5% of a suitable cross-linking agent and from 0% to 2% of a UV absorber.
    Type: Grant
    Filed: July 21, 1989
    Date of Patent: April 21, 1992
    Assignee: Ioptex Research Inc.
    Inventor: Amitava Gupta
  • Patent number: 5080472
    Abstract: A multifocal lens useful as a contact lens or implantable as an intraocular lens which comprises at least 3 zones, the first zone comprising a polymer of a specified refractive index, the second zone comprising a polymer having the same repeating units as the polymer comprising the first zone and having a specified refractive index differing from the refractive index of the polymer comprising the first zone by not more than 0.1 units and by not less than 0.01 units and the third zone between the first and second zones comprising a polymer having the same repeating units as the polymers comprising the first and second zones and having a refractive index continuously variable between that of the polymer comprising the first zone and that of the polymer comprising the second zone, the at least three zones being transparent and having no discontinuities visible to the human eye between the zones.
    Type: Grant
    Filed: July 21, 1989
    Date of Patent: January 14, 1992
    Assignee: Ioptex Research Inc.
    Inventor: Amitava Gupta
  • Patent number: 4945001
    Abstract: A new polycarbonate copolymer resin is formed by internal generation of stabilizers bound to the polymer chain. Irradiation of a solid piece or a deoxygenated solution of the resin at a first frequency below 300 nm generates 2 to 8 mol percent of phenyl salicylate groups which are rearranged to dihydroxybenzophenone groups by irradiating the resin under oxygen excluding conditions at a second frequency from 300 to 320 nm.
    Type: Grant
    Filed: May 31, 1988
    Date of Patent: July 31, 1990
    Assignee: California Institute of Technology
    Inventors: Amitava Gupta, Ranty H. Liang, Andre H. Yavrouian
  • Patent number: 4834750
    Abstract: A deformable-elastic intraocular lens comprising a deformable-elastic lens body of crosslinked acrylic material formed of copolymers of methacrylate and acrylate esters which are relatively hard and relatively soft at body temperature, crosslinked with a diacrylate ester to produce an acrylic copolymer having a substantially tack-free surface, a crosslink density of between 0.5.times.10.sup.-2 and 1.5 .times.10.sup.-2 moles per liter, and glass transition temperature in the range of -30.degree. C. to 25.degree. C., a tensile modulus between 1000 and 3000 psi and a elongation a break of 100% or greater.
    Type: Grant
    Filed: September 17, 1987
    Date of Patent: May 30, 1989
    Assignee: Ioptex Research, Inc.
    Inventor: Amitava Gupta
  • Patent number: 4813956
    Abstract: A method of forming single-piece intraocular lenses comprising the steps of forming a thin sheet of colored polymethyl methacrylate, coring the sheet to form holes therein, filling the holes with a clear or differently colored PMMA material, polymerizing the colored and clear or differently colored PMMA material comprising the sheet and filled holes, cutting core members from the polymerized sheet each having an inner circular region of PMMA material and an outer region of colored PMMA material and machining a single-piece intraocular lens from a core member to have a central lens body of PMMA material and colored PMMA positioning loops extending from and integral with the central lens body.
    Type: Grant
    Filed: April 3, 1987
    Date of Patent: March 21, 1989
    Assignee: Ioptex Research, Inc.
    Inventor: Amitava Gupta
  • Patent number: 4749726
    Abstract: A new polycarbonate copolymer resin is formed by internal generation of stabilizers bound to the polymer chain. Irradiation of a solid piece or a deoxygenated solution of the resin at a first frequency below 300 nm generates 2 to 8 mol percent of phenyl salicylate groups which are rearranged to dihydroxybenzophenone groups by irradiating the resin under oxygen excluding conditions at a second frequency from 300 to 320 nm.
    Type: Grant
    Filed: December 8, 1986
    Date of Patent: June 7, 1988
    Assignee: California Institute of Technology
    Inventors: Amitava Gupta, Ranty H. Liang, Andre H. Yavrouian
  • Patent number: 4655770
    Abstract: An intraocular lens is treated to form a modified passivated outer surface for reducing or eliminating biological reactions of inflammatory origin when the lens is implanted into an eye. The lens is formed from a conventional lens implant material, such as polymethyl methacrylate (PMMA), which is treated as required to create an outer surface region including a relatively high density of hydroxyl groups. This outer surface region is reacted with a selected fluorocarbon carried in a solution with a primer including bonding agents for bonding the fluorocarbon with respect to the hydroxyl groups, thereby creating a thin, substantially inert or passivated outer surface resistant to irritative reaction with tissue or cells when the lens is implanted into the eye.
    Type: Grant
    Filed: June 6, 1985
    Date of Patent: April 7, 1987
    Assignee: Ioptex, Inc.
    Inventors: Amitava Gupta, Robert L. Van Osdel
  • Patent number: 4383129
    Abstract: A polymer syrup for encapsulating solar cell assemblies. The syrup includes uncrosslinked poly(n-butyl)acrylate dissolved in n-butyl acrylate monomer. Preparation of the poly(n-butyl)acrylate and preparation of the polymer syrup is disclosed.Methods for applying the polymer syrup to solar cell assemblies as an encapsulating pottant are described. Also included is a method for solar cell construction utilizing the polymer syrup as a dual purpose adhesive and encapsulating material.
    Type: Grant
    Filed: May 21, 1982
    Date of Patent: May 10, 1983
    Assignee: California Institute of Technology
    Inventors: Amitava Gupta, John D. Ingham, Andre H. Yavrouian
  • Patent number: 4374955
    Abstract: A polymer syrup for encapsulating solar cell assemblies. The syrup includes uncrosslinked poly(n-butyl)acrylate dissolved in n-butyl acrylate monomer. Preparation of the poly(n-butyl)acrylate and preparation of the polymer syrup is disclosed.Methods for applying the polymer syrup to solar cell assemblies as an encapsulating pottant are described. Also included is a method for solar cell construction utilizing the polymer syrup as a dual purpose adhesive and encapsulating material.
    Type: Grant
    Filed: June 11, 1980
    Date of Patent: February 22, 1983
    Assignee: California Institute of Technology
    Inventors: Amitava Gupta, John D. Ingham, Andre H. Yavrouian
  • Patent number: 4362895
    Abstract: Photostable and weather stable absorping copolymers have been prepared from acrylic esters such as methyl methacrylate containing 0.1 to 5% of an 2-hydroxy-allyl benzophenone, preferably the 4,4' dimethoxy derivative thereof. The pendant benzophenone chromophores protect the acrylic backbone and when photoexcited do not degrade the ester side chain, nor abstract hydrogen from the backbone.
    Type: Grant
    Filed: September 21, 1981
    Date of Patent: December 7, 1982
    Assignee: California Institute of Technology
    Inventors: Amitava Gupta, Andre H. Yavrouian
  • Patent number: 4310650
    Abstract: Photostable and weather stable absorping copolymers have been prepared from acrylic esters such as methyl methacrylate containing 0.1 to 5% of an 2-hydroxy-allyl benzophenone, preferably the 4,4' dimethoxy derivative thereof. The pendant benzophenone chromophores protect the acrylic backbone and when photoexcited do not degrade the ester side chain, nor abstract hydrogen from the backbone.
    Type: Grant
    Filed: March 3, 1980
    Date of Patent: January 12, 1982
    Assignee: California Institute of Technology
    Inventors: Amitava Gupta, Andre H. Yavrouian
  • Patent number: 4262198
    Abstract: A method and apparatus for detecting optical radiation by optically monitoring temperature changes in a microvolume caused by absorption of optical radiation to be detected. More specifically, a thermal lens-forming material is provided which has first and second opposite, substantially parallel surfaces. A reflective coating is formed on the first surface, and a radiation-absorbing coating is formed on the reflective coating. Chopped, incoming optical radiation to be detected is directed to irradiate a small portion of the radiation-absorbing coating. Heat generated in this small area is conducted to the lens-forming material through the reflective coating, thereby raising the temperature of a small portion of the lens-forming material and causing a thermal lens to be formed therein. The thus-formed thermal lens is optically detected by irradiating the thermal lens by a collimated light beam.
    Type: Grant
    Filed: July 30, 1979
    Date of Patent: April 14, 1981
    Assignee: California Institute of Technology
    Inventors: Amitava Gupta, Su-Don Hong, Jovan Moacanin
  • Patent number: 4259223
    Abstract: Microspheres are produced by cobalt gamma radiation initiated polymerization of a dilute aqueous vinyl pyridine solution. Addition of cross-linking agent provides higher surface area beads. Addition of monomers such as hydroxyethylmethacrylate acrylamide or methacrylamide increases hydrophilic properties and surface area of the beads. High surface area catalytic supports are formed in the presence of controlled pore glass substrate.
    Type: Grant
    Filed: October 2, 1978
    Date of Patent: March 31, 1981
    Assignee: California Institute of Technology
    Inventors: Alan Rembaum, Amitava Gupta, Willi Volksen