Patents by Inventor Carl H. Evans

Carl H. Evans 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: 4199231
    Abstract: A soft contact lens provided with a front surface whose cross section describes the curve whose equation, in polar coordinates, is .rho.=R+kR(1-cos .theta.)/(1+cos .theta.) where R is the radius of curvature of a spherical lens of power equal at least approximately to the most hyperopic (or least myopic) power meridian of the ametropia plus about one-half of any presbyopic addition required by the patient, and k is a constant of eccentricity which may vary with the hydrophilic properties of the lens material and is determined for each material such that the visual acuity for distance and near vision is 20/20 or better with the aforesaid R value. The value of k lies within the range 0.005 to 0.1.
    Type: Grant
    Filed: August 21, 1978
    Date of Patent: April 22, 1980
    Inventor: Carl H. Evans