Invention Grant
- Patent Title: Location-based swing compensation for touch channel attenuation
-
Application No.: US15698471Application Date: 2017-09-07
-
Publication No.: US11137858B2Publication Date: 2021-10-05
- Inventor: Albert Lin , Shwetabh Verma , Sumant Ranganathan
- Applicant: Apple Inc.
- Applicant Address: US CA Cupertino
- Assignee: Apple Inc.
- Current Assignee: Apple Inc.
- Current Assignee Address: US CA Cupertino
- Agency: Kubota & Basol LLP
- Main IPC: G06F3/041
- IPC: G06F3/041 ; G06F3/044

Abstract:
Location-based swing compensation for touch sensor panels can improve touch sensing performance. Due to differences in impedance characteristics of touch nodes at different locations in a touch sensor panel (due to differences in routing to touch nodes and due to differences in impedance with respect to ground (loading effects) of touch nodes), touch nodes can have non-uniform bandwidth characteristics which can manifest as non-uniform signal and signal-to-noise ratio (SNR) across the touch sensor panel. Additionally, the non-uniform signal can reduce the effectiveness of bootstrapping. Swing compensated stimulation signals can be applied to various touch nodes based on location and/or impedance characteristics of the various touch nodes. For example, the stimulation voltage can be increased for touch nodes with longer and/or thinner routing traces so that the signal at the touch node can be uniform with other touch nodes whose routing may be shorter and/or thicker. In some examples, a touch sensing system can include a swing compensation memory including swing compensation parameters to select stimulation signal swing for transmit channels.
Public/Granted literature
- US20180088735A1 LOCATION-BASED SWING COMPENSATION FOR TOUCH CHANNEL ATTENUATION Public/Granted day:2018-03-29
Information query