Touch Sensor Electrode Layout for Pen and Palm Signal Separation
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Solution Overview
Problem
Existing touch screens, particularly capacitive touch screens, suffer from operation errors due to unintentional hand contact and abnormal touch signals in non-touched areas, and significant capacitance increases when pen driving and receiving electrodes are grounded, leading to coupling capacitance and mutual capacitance issues.
Innovation Solution
The electronic device employs a sensor unit with multiple patterns of electrodes, including touch driving and receiving electrodes, and a control unit that operates in mutual-sensing and self-sensing modes to prevent abnormal touch signals and reduce capacitance by grounding pen driving and receiving electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a C-type touch screen is used to detect touch position, then touch operation can be performed, but operation errors occur due to unintentional hand contact and difficulty in distinguishing hand from pen
Solution Approach 1:
The touch sensor is divided into multiple independent sensing lines arranged in parallel, with each line capable of detecting touch position independently. This segmentation allows the system to distinguish between hand contact and pen contact by analyzing the spatial distribution of touch signals across multiple sensing lines, thereby improving operation accuracy while maintaining ease of use.
Solution Approach 2:
A driving signal is introduced as an intermediary to activate the sensing lines. The driving signal is applied to alternating sensing lines in a sequential manner, creating a time-multiplexed sensing mechanism. This allows the system to distinguish between continuous hand contact and discrete pen contact based on the temporal pattern of signal activation, resolving the ambiguity between hand and pen identification.
2Object-generated harmful factors
If pen driving electrode and pen receiving electrode are grounded to prevent abnormal signals, then coupling capacitance and mutual capacitance are reduced, but capacitance of touch electrodes increases significantly
Solution Approach 1:
The sensing lines are activated in a periodic sequential manner rather than simultaneously. The driving signal is applied to one sensing line, then switched to the next line in sequence. This periodic activation pattern reduces the simultaneous capacitance coupling between adjacent electrodes while maintaining the ability to detect touch position accurately through temporal sequencing of the sensing process.
3Measurement precision
If multiple sensing lines are used to improve touch detection accuracy, then abnormal touch signals in non-touched areas are reduced, but device complexity increases
Solution Approach 1:
Multiple sensing lines are merged into a single integrated touch sensor structure that can be controlled by a unified control mechanism. The sensing lines are electrically connected and controlled through a common driving circuit that sequentially activates them. This merging approach allows the system to achieve high measurement precision through multiple sensing lines while avoiding the complexity of independent control circuits for each line.
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
This solution effectively prevents abnormal touch signals in non-touched areas and minimizes capacitance increases, ensuring accurate touch detection and reducing signal interference.
Implementation Method 1
the C-type touch screen is a touch screen which operates by detecting a difference in capacitance of a transparent electrode caused by contacting an object
Implementation Method 2
preventing coupling capacitance and mutual capacitance from occurring when a pen driving electrode and a pen receiving electrode are grounded
Data Source
AI summary
Disclosed is an electronic device comprising: a sensor unit; and a control unit, wherein the sensor unit comprises a plurality of first patterns extending in a first direction; a plurality of second patterns extending in the first direction, wherein the plurality of second patterns are disposed adjacent to the plurality of first patterns and have one ends that are electrically connected to each other; a plurality of third patterns extending in a second direction perpendicular to the first direction; and a plurality of fourth patterns extending in the second direction, wherein the plurality of fourth patterns are disposed adjacent to the plurality of third patterns and have one ends that are electrically connected to each other.