×

Capacitance detection apparatus

  • US 20060170411A1
  • Filed: 01/24/2006
  • Published: 08/03/2006
  • Est. Priority Date: 01/28/2005
  • Status: Active Grant
First Claim
Patent Images

1. A capacitance detection apparatus for detecting approach of an object on the basis of a change of capacitance, comprising:

  • a detection electrode for detecting the change of the capacitance bby approaching the object;

    a calculating circuit for calculating a value associated with the change of the capacitance detected by the detection electrode;

    a judging circuit for judging whether the value calculated by the calculating circuit is a normal value which is calculated after a predetermined period of time lapse from a start time of the capacitance detection apparatus or an initial value which is calculated before the predetermined period of time lapse from the start time of the capacitance detection apparatus;

    an initial reference value-determining circuit for determining an initial reference value for the value judged by the judging circuit as the initial value;

    a difference calculating circuit for calculating a difference between the value judged by the judging circuit as the normal value and a value calculated at a time earlier than a time when the value judged by the judging circuit as the normal value is calculated by the predetermined period of time or longer, or a difference between the value judged by the judging circuit as the initial value and the initial reference value determined by the initial reference value-determining circuit; and

    a determining circuit for determining whether or not the object is approaching by comparing the difference calculated by the difference calculating circuit with a predetermined threshold value.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×