Patents by Inventor Randall S. Lawson

Randall S. Lawson 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: 5444566
    Abstract: A method for controlling a digital micromirror device 40 resulting in decreased mechanical stress, longer device lifetimes, decreased incidence of spontaneous bit reset, and increased pulse-width modulation accuracy. To reduce the device stress, the bias voltage 142 applied to the mirror 50 may be reduced after the mirror 50 has been latched. To prevent premature mirror changes, the address electrode bias voltage 140 may be reduced after the mirror is driven to the desired position. To ensure that the mirror 50 returns to the neutral position during reset, the mirror bias voltage 142 may be raised from ground potential to approximately halfway between the two addressing voltages during the reset period 152. To reduce the effects of hinge memory and to ensure that the mirror 50 rotates toward the proper address electrode, the mirror bias voltage 142 may be gradually increased to allow the mirror 50 time to rotate towards the proper address electrode.
    Type: Grant
    Filed: March 7, 1994
    Date of Patent: August 22, 1995
    Assignee: Texas Instruments Incorporated
    Inventors: Richard O. Gale, Randall S. Lawson, Harlan P. Cleveland, Henry Chu, Carl W. Davis, Scott D. Heimbuch, Claude E. Tew
  • Patent number: 4924974
    Abstract: An elevator system including a door post having inner and outer sides, and a hall lantern assembly fixed to the inner side. The door post includes a jamb defining upper and lower openings, and the hall lantern assembly includes upper and lower lenses which are resiliently biased to project through the upper and lower openings, respectively, in operating positions of the lenses. The upper and lower lenses have service positions achievable by depressing a lens against the bias, and then slidably moving the lens in a vertical direction, with the service positions of the upper and lower lenses enabling the hall lantern assembly to be serviced through the upper and lower openings in the jamb.
    Type: Grant
    Filed: January 11, 1989
    Date of Patent: May 15, 1990
    Assignee: Inventio AG
    Inventors: Karl B. Orndorff, Randall S. Lawson