Patent ID: 8416209

Claim:
A computer system comprising: a processor configured to execute instructions and to carry out operations associated with the computer system; a display device that is operatively coupled to the processor; a touch screen that is operatively coupled to the processor, the touch screen being a substantially transparent panel that is positioned in front of the display device, the touch screen being configured to track multiple objects, which rest on, tap on or move across the touch screen at the same time, the touch screen comprising: a first layer having a plurality of first transparent conductive lines that are electrically isolated from one another; and a second layer spatially separated from the first layer by one or more non-conducting members and having a plurality of second transparent conductive lines that are electrically isolated from one another, the plurality of second transparent conductive lines being positioned transverse to the plurality of first transparent conductive lines, the intersection of the plurality of first transparent conductive lines and the plurality of second transparent conductive lines forming mutual capacitance sensing nodes positioned at different locations in the plane of the touch screen; one of the plurality of first transparent conductive lines and the plurality of second transparent conductive lines being driving lines and the other being sensing lines; the sensing lines being coupled to filters; the filters coupled to capacitive sensing circuitry; and wherein the filters includes at least a virtual ground charge amplifier.