Multi-bar capacitive sense electrode wobble error reduction
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Solution Overview
Problem
Touch sensitive devices experience wobble error in position detection when a stylus or finger is positioned between sense electrodes, due to non-linear signal profiles, leading to inaccuracies in calculating the object's position on a touch sensor panel.
Innovation Solution
Configuring sense electrodes with multiple bars extending along their length, connected at ends, and employing non-uniform spacing and split-bar configurations to create more linear signal profiles, thereby reducing wobble error and improving position calculation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional single-bar sense electrodes are used, then the device structure is simple, but wobble error increases and position detection accuracy deteriorates
Solution Approach 1:
The sense electrode is divided into multiple bars (first bar, second bar, third bar, etc.) arranged along the length of the electrode. Each bar independently contributes to the capacitive signal, creating a more distributed and linear signal profile that reduces wobble error when the touch object is positioned between electrodes.
Solution Approach 2:
Different bars within the same electrode are positioned at different locations to create a more uniform signal distribution across the electrode length. This local variation in bar positioning optimizes the signal profile shape to be more linear, improving position detection accuracy without requiring a complete redesign of the entire electrode system.
2Measurement precision
If signal profile is narrowed for higher resolution, then electrode spacing can be reduced, but wobble error increases due to non-linearity
Solution Approach 1:
Instead of simply widening the signal profile in one dimension, the invention distributes multiple bars along the length of the electrode, transforming the signal distribution from a single-peaked narrow profile to a more extended linear profile across multiple positions, thereby improving linearity without excessive width expansion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed electrode configurations result in lower wobble error and more accurate position detection by creating a more linear signal profile, enhancing the performance of touch sensor panels, particularly when using styluses or fingers.
Implementation Method 1
Multi-bar capacitive sense electrode... Touch sensor panel can include a first electrode including a first plurality of electrically connected bars... and a second electrode
Data Source
AI summary
Electrode configurations for reducing wobble error for a stylus translating on a surface of a touch sensor panel is disclosed. Electrodes associated with a more linear signal profile can correlate to lower wobble error. In some examples, electrodes can be configured such that the signal profile associated with each electrode is spread to be wider, and thus, more linear. In some configurations, electrodes can include two or more bars extending along the length of the electrode with each bar electrically connected to one another at one or both ends. Bars can be of non-uniform width or spacing. Some configurations can include a “split bar,” which can divide a bar lengthwise in order to improve optical uniformity. In some examples, electrodes can include projections which can interleave with corresponding projections in adjacent electrodes.