Patents Assigned to Varitronix Limited
  • Conductive touch pad with capacitive blocking filter
    Patent number: 5499026
    Abstract: A touch sensitive pad consists of a number of electrical conductive pads (10) surrounded by a conductive pad (11). Each pad (10) is connected via a respective capacitive blocking filter to a multiplexer (13) and an oscillator (14). When the touch pad is touched directly to effectively bridge between one of the pads (10) and the surrounding pad (11), a change in effective impedance is detected by a resultant variation in the frequency of the oscillator (14).
    Type: Grant
    Filed: September 30, 1994
    Date of Patent: March 12, 1996
    Assignee: Varitronix Limited
    Inventors: York Liao, Michael Y. S. Chan