Patents Assigned to Polycore Optical Pte. Ltd.
  • Progressive addition lens
    Patent number: 4426139
    Abstract: A progressive addition lens is provided having a wide transition corridor and an improved balance between astigmatism and distortion in the field of peripheral vision to provide a wide, distortion-free clear view. This is achieved by employing a cosine function in blending the transition corridor with the peripheral area.
    Type: Grant
    Filed: April 8, 1982
    Date of Patent: January 17, 1984
    Assignee: Polycore Optical Pte. Ltd.
    Inventors: Raoul F. van Ligten, Yeo K. Kee