Invention Grant
- Patent Title: Error compensation for multi-touch surfaces
- Patent Title (中): 多点触摸表面的误差补偿
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Application No.: US11650204Application Date: 2007-01-03
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Publication No.: US07692638B2Publication Date: 2010-04-06
- Inventor: Brian Richards Land , Steve Porter Hotelling
- Applicant: Brian Richards Land , Steve Porter Hotelling
- Applicant Address: US CA Cupertino
- Assignee: Apple Inc.
- Current Assignee: Apple Inc.
- Current Assignee Address: US CA Cupertino
- Agency: Morrison & Foerster LLP
- Main IPC: G09G5/00
- IPC: G09G5/00

Abstract:
Normalization of the built-in DC offset error in each analog channel is disclosed to reduce image distortion in multi-event (multi-touch or multi-hover) sensor panels. By eliminating the component-dependent offset error from each analog channel, each analog channel will generate approximately the same output value for a given dynamic input signal. Normalization can include “phantom row” compensation, which involves measuring the static output value of each analog channel when no stimulus is applied to any row of a multi-event sensor panel, and subtracting this value out of any subsequent output value generated by the analog channel. Normalization can also include DAC offset compensation, which involves setting the offset compensation voltage of each analog channel to some fraction of its normal value, measuring the output of the analog channel over temperature, determining a temperature coefficient, and adjusting any subsequent output value generated by the analog channel to account for this drift.
Public/Granted literature
- US20080158184A1 Error compensation for multi-touch surfaces Public/Granted day:2008-07-03
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