×

Capacitive position sensor

  • US 8,217,915 B2
  • Filed: 08/12/2004
  • Issued: 07/10/2012
  • Est. Priority Date: 08/21/2003
  • Status: Active Grant
First Claim
Patent Images

1. A capacitive position sensor comprising:

  • a substrate;

    a single resistive sensing element forming a continuous resistor supported by the substrate in an angular route; and

    three spaced-apart terminals disposed along the single resistive sensing element to couple to separate sensing channels, wherein signals from the three spaced-apart terminals are representative of a position of a touch along the single resistive sensing element;

    each sensing channel being operable to generate a signal indicative of a capacitance for a respective terminal coupled to the sensing channel, the position of the touch along the single resistive sensing element being determinable by performing operations comprising;

    determining a section of the single resistive sensing element corresponding to the touch, the determined section being between a first terminal and an adjacent second terminal;

    subtracting a signal of a respective sensing channel coupled to a third terminal from each of signals taken from respective sensing channels coupled to the first and the second terminals to generate first and second reduced signals; and

    determining the position of the touch within the determined section using a ratiometric analysis of the first and second reduced signals.

View all claims
  • 18 Assignments
Timeline View
Assignment View
    ×
    ×