Test methods for capacitive touch screens, and capacitive touch screen assemblies

A method of testing a capacitive touch screen, during the operation of which a respectively unique drive signal is applied to each of a first plurality of lines, and each of a second plurality of lines is responsive to each of the respectively unique signals, wherein a change in a response on a one of the second plurality of lines to a one of the unique drives signals is indicative of a touch event at a cross-point of the respective one of the first plurality of lines with the respective one of the second plurality of lines, the method comprising:

• modifying an amplitude of the respective unique drive signal applied to each of the first plurality of lines;
• and
• in the event of identifying a response to each modified amplitude, on each of the second plurality of lines,
• determining that the touch screen does not have a fault,
• and otherwise determining that the touch screen has a fault.

A capacitive touch screen assembly, comprising:

• a first plurality of lines, each having a driver therefor;
• a second plurality of lines each having a receiver therefor;
• a respective cross-point between each of the first plurality of lines;
• and a controller;
• wherein the drivers are each configured to apply a respectively unique drive signal to the respective line of the first plurality;
• wherein a change in a response at a one of the receivers to a one of the unique drives signals is indicative of a touch event at a corresponding cross-point;
• wherein the controller is configured to:
• control the drivers to modify an amplitude of the respective unique drive signal applied to each of the first plurality of lines;
• and
• in the event of identifying a response to each modified amplitude, on each of the second plurality of read lines,
• determine that the touch screen does not have a fault,
• and otherwise determine that the touch screen has a fault.