CAPACITIVE PROXIMITY DETECTION SYSTEM AND METHOD

摘要

A touch screen controller system for controlling a touch screen having row conductors and column conductors includes analog-digital circuitry coupled to the row conductors and column conductors to produce digital signals representative of self capacitance changes of one of the column conductors during an element proximity scanning mode and also representative of mutual changes of the touch screen during an element location scanning mode. The analog-digital circuitry indicates the influence of an element on the self-capacitance during the element proximity scanning. Proximity-determining circuitry operates on the digital signal changes during the element proximity scanning to determine if the element is proximate to the touch screen, and also to determine if the element is a specific kind of element by comparing the digital signal changes to a predetermined data profile.

主权项

1. A touch screen controller system for controlling a touch screen having a first number of row conductors and a second number of column conductors, comprising:
(a) analog-digital circuitry coupled to the row conductors and the column conductors of a touch screen for producing a first digital signal representative of a self capacitance of one of the column conductors during an element proximity scanning mode and also representative of mutual capacitances of the touch screen during an element location scanning mode, the analog-digital circuitry operating to produce information representative of the influence of an element on the self-capacitance during the element proximity scanning mode; (b) touch presence monitoring circuitry for operating on a second digital signal representative of a change in the first digital signal during the element proximity scanning mode to determine if the element is touching the touch screen; and (c) specific-element proximity-determining circuitry for operating on the second digital signal during the element proximity scanning mode to determine if the element is proximate to the touch screen, and also to determine whether the element is a specific kind of element by comparing the second digital signal to a predetermined data profile corresponding to the specific kind of element.