Circular Touch Sensor Radial Electrode Arrangement
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Solution Overview
Problem
Conventional touch sensor devices with quadrangular touch sensing areas are limited in their ability to precisely sense multiple touches and do not offer enhanced price competitiveness.
Innovation Solution
A touch sensor device with a non-quadrangular touch sensing area, such as circular or elliptical, where touch sensors are disposed radially from an imaginary central point, with varying widths and areas, and touch wires connected to touch drivers, allowing for precise touch position detection using polar coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a quadrangular touch sensing area is used, then the manufacturing process is simple, but the ability to precisely sense multiple touches is limited
Solution Approach 1:
The touch sensing area is divided into multiple domains with imaginary boundary lines, and touch sensors are segmented and disposed in each domain. This segmentation allows precise detection of multiple touch positions by determining which domain each touch occurs in, thereby improving measurement precision while maintaining manageable structural complexity.
Solution Approach 2:
The patent transitions from a conventional quadrangular coordinate system to a polar coordinate system with an imaginary central point. Touch sensors are disposed radially from this central point, and touch positions are determined using radial distance and angular position. This dimensional change enables more precise multi-touch sensing by utilizing angular information in addition to radial distance.
2Ease of manufacture
If a non-quadrangular touch sensing area is used, then price competitiveness increases, but the manufacturing process becomes more complex
Solution Approach 1:
The patent employs asymmetric arrangement of touch sensors in radial directions from the imaginary central point, with each domain having specific angular boundaries. This asymmetric polar arrangement allows the use of non-quadrangular sensing areas (circular, elliptical, or irregular shapes) while maintaining manufacturing feasibility through systematic domain division and standardized sensor placement within each domain.
Solution Approach 2:
The patent changes the coordinate system parameters from Cartesian (x, y) to polar (r, θ), allowing flexible definition of the touch sensing area shape. By defining domains through angular ranges and radial distances, the system can accommodate various shapes (circular, elliptical, irregular) without fundamentally changing the manufacturing approach, thus balancing manufacturing ease with precision requirements.
3Reliability
If touch sensors are disposed radially from a central point with varying areas, then multiple touches can be precisely sensed, but the device structure becomes more complex
Solution Approach 1:
Each touch sensor domain is assigned specific local characteristics including angular boundaries, radial extent, and sensor area size. The area of touch sensors gradually increases as distance from the imaginary central point increases, optimizing sensing capability in different regions. This localized optimization improves multi-touch sensing reliability while keeping the overall structure manageable through systematic domain assignment.
Solution Approach 2:
The radial-polar touch sensor arrangement serves multiple functions simultaneously: it enables precise single-touch detection, accurate multi-touch position identification, and determination of touch direction relative to the central point. The same sensor configuration handles various touch scenarios (single touch, multiple touches, light touches, heavy presses) without requiring separate detection mechanisms, thereby improving reliability without proportionally increasing complexity.
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
Enables precise sensing of multiple touches and increased price competitiveness by simplifying the manufacturing process and improving user interface experience with a circular or elliptical touch sensing area.
Implementation Method 1
The capacitive touch sensor may include a sensing capacitor formed by a sensing electrode that may transfer a sensing signal, and sense a change in capacitance of the sensing capacitor generated when a conductor such as a finger approaches the touch sensor
Data Source
AI summary
A touch sensor device includes a touch sensing area including touch sensors sequentially disposed in a first direction extending away from an imaginary central point, in which an area of each touch sensors gradually increases as a distance thereof away from the imaginary center point increases, at least one of the touch sensors includes a first touch electrode and a second touch electrode adjacent to each other, a width of the first touch electrode decreases along a second direction, and a width of the second touch electrode increases along the second direction.