Apple Inc.

Santosh Pokhrel

Karan S Jain

Supratik Datta

Nandita Venugopal

Touch electrode architectures for reducing the occurrence of negative pixels in mutual capacitance touch sensor panels that are caused by poorly grounded objects are disclosed. A touch electrode architecture can utilize mutual capacitance unit cells, each of which include a drive electrode, a sense electrode, and one or more ground bars. The one or more ground bars can provide an increased capacitive path to ground for a poorly grounded finger, which can result in a larger reduction in mutual capacitance between the drive and sense electrodes, improving touch detection. In addition, the increased capacitive coupling between the object and ground reduces the amount of charge that couples back onto nearby sense electrodes, which can reduce the negative pixel that can occur at those electrodes and reduce the number of touch detection errors. The one or more ground bars can be formed in the same layer as the drive electrode.

Apparatus to reduce negative pixel from capacitive touch

Touch sensor panels/screens can include negative temperature coefficient materials in the stack-up and routing traces with expanded areas to reduce thermal drift and minimize the detection of false touches. In some examples, the touch sensor panels/screens can include a plurality of touch electrodes in a first layer. In some examples, the sensor panels/screens can include one or more dielectric materials in a second layer, the one or more dielectric materials including a negative temperature coefficient material. In some examples, the touch sensor panels/screens can include a plurality of routing traces in a third layer, the plurality of routing traces routing the plurality of touch electrodes to a touch controller chip.

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San Francisco, CA, United States of America

Santosh Pokhrel