METHOD FOR CALIBRATING AND MANUFACTURING A FORCE-SENSING TOUCH SCREEN PANEL

摘要

A method and apparatus for calibrating a force sensing touch screen panel includes determining calibration factors for the position sensing layers of the touch screen panel, and applying those calibration factors to adjust nominal resistance values for resistance components of the position sensing layers when force is applied to the touch screen panel. The calibration factors result in a more accurate determination of the resistance of a force sensing layer which changes resistance as a function of force applied to the touch screen panel. The resistance of the force sensing layer can be used to determine the force applied based on a curve relating force to resistance.

主权项

1. A method of calibrating a pressure metric for touch screen panel, comprising:
measuring an electrical resistance of a upper calibration trace of an upper position sensing layer of the touch screen panel, and measuring an electrical resistance of a lower calibration trace of a lower position sensing layer of the touch screen panel; determining an upper calibration factor as a ratio of the measured electrical resistance of the upper calibration trace to a nominal upper resistance, and determining a lower calibration factor as a ratio of the measured electrical resistance of the lower calibration trace to a nominal lower resistance; determining a total resistance through a point at which a force is applied on the touch screen panel, the total resistance including an upper layer component, a lower layer component, and a force sensing layer component, wherein the force sensing layer component is a resistance of a compressible material between the upper and lower component layers; determining an electrical resistance of the force sensing layer component by subtracting a corrected upper layer component and a corrected lower layer component from the total resistance, wherein the corrected upper layer component and corrected lower layer components are produced by applying the upper calibration factor and lower calibration factor to the upper layer component and lower layer component, respectively; and determining the force applied on the touch screen panel by mapping the electrical resistance of the force sensing layer to the force applied on a curve of force sensing layer resistance over force.