Maxim Integrated Products, Inc.

Qualcomm Technologies, Inc.

Muhammad Umair

Roberto Alini

Lee Coleman

Paul Nickson

Arshad Suhail Farooqui

Guozhong Shen

Kenneth W Knox

Bart Decanne

Syed Fawad Ahmad

Transducers formed as part of a touchscreen system emulate the motion of a pushbutton or other mechanical elements. A touchscreen system positions a transducer adjacent to an icon displayed on the touchscreen surface. When a user touches the icon, the transducer senses the touch and is then deformed in a pattern that emulates a mechanical motion, giving the user the sensation of touching a mechanical button. An excitation signal applied to the transducer is compared to a target excitation signal that, when applied to the transducer, causes the transducer to emulate the desired motion. When any differences between the two signals are detected, the excitation signal is adjusted so that the motion is corrected. The target excitation signal, or time and voltage segments defining it, are stored in memory and retrieved for comparison. The excitation signal is also selected to reduce any acoustic artifacts that can cause the transducer to generate audible clicks.

Method and apparatus for generating piezoelectric transducer excitation waveforms using a boost converter

A capacitive touch panel is tested for the presence or absence of short and open circuits in drive and sense lines without the use of a tool that touches the surface of the panel. During a first stage of testing, drive lines of the touch panel are sequentially driven while the remaining drive lines are floated. Sense lines are read to indicate whether a driven drive line is shorted to an adjacent drive line, an open circuit, or coupled to a sense line that is an open circuit. During a second stage of testing, drive lines are driven while alternate sense lines are floated or enabled. The signals on the enabled sense lines are acquired to indicate whether the enabled sense lines are shorted to adjacent sense lines. This second stage can be repeated, switching the roles of the sense lines, to determine the locations of short and/or open circuits.

Touch panel testing using mutual capacitor measurements

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Santa Clara, CA, United States of America

Muhammad Umair