Patents by Inventor Dwight W. Berreman

Dwight W. Berreman 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).

  • Matrix addressed bistable liquid crystal display
    Patent number: 4529271
    Abstract: A matrix addressed, bistable liquid crystal optical display is disclosed. The display includes a liquid crystal twist cell which has at least two states which are stable in the presence of a single given holding voltage. A form of 3:1 matrix addressing is used in the display which enhances operational characteristics.
    Type: Grant
    Filed: March 12, 1982
    Date of Patent: July 16, 1985
    Assignee: AT&T Bell Laboratories
    Inventors: Dwight W. Berreman, William R. Heffner, Allan R. Kmetz
  • Bistable liquid crystal twist cell
    Patent number: 4505548
    Abstract: A bistable liquid crystal twist cell is disclosed. The cell has at least two states which are stable in the presence of a single given holding voltage. The states may be switched from one to the other by short-term variation in the magnitude of the applied voltage.
    Type: Grant
    Filed: October 12, 1983
    Date of Patent: March 19, 1985
    Assignee: AT&T Bell Laboratories
    Inventors: Dwight W. Berreman, William R. Heffner
  • Bistable liquid crystal twist cell
    Patent number: 4239345
    Abstract: A bistable liquid crystal twist cell is disclosed. The cell is characterized by at least two stable states which exist indefinitely as long as not external energy is applied to the cell. External energy is necessary only for switching the cell between the stable states. Cell configurations which permit the fabrication of patterned displays are additionally disclosed. Specific embodiments include new techniques for switching the cell between the stable states.
    Type: Grant
    Filed: April 16, 1979
    Date of Patent: December 16, 1980
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventors: Dwight W. Berreman, William R. Heffner
  • Variable focus liquid crystal lens system
    Patent number: 4190330
    Abstract: An optical lens system is disclosed which comprises a body of a nematic liquid crystal material placed in a variable electric or magnetic field. In response to variation of the field strength from zero to an upper limit, the focal length of the lens system changes continuously from a first focal length to a second focal length. The new lens system may be used, e.g., in cameras, telescopes, binoculars, projectors, and eyeglasses.
    Type: Grant
    Filed: December 27, 1977
    Date of Patent: February 26, 1980
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Dwight W. Berreman