Multi-Channel Touch Sensing with Switched Sensor Groups
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Solution Overview
Problem
Touch sensing systems face challenges in accurately detecting touches while minimizing power consumption and reducing the area required for sensor arrays, especially in large touch panels, due to increased parasitic components and routing congestion.
Innovation Solution
A touch sensing apparatus utilizing a multi-channel approach with a sensor array divided into groups, where each group is connected to either a first or second channel via switch circuits, allowing for efficient signal processing and reduced signal lines, enabling quick detection of touches across a wide area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a sensor array is used for large touch panels, then the sensing area is increased, but parasitic components and routing congestion increase
Solution Approach 1:
The sensor array is divided into multiple sensor groups, where each group shares common signal lines. This segmentation reduces the total number of independent signal lines required, thereby reducing routing congestion while maintaining large sensing area coverage.
Solution Approach 2:
Common signal lines are designed to serve multiple sensor groups simultaneously. These signal lines perform multiple functions by routing signals to different sensor groups based on control signals, reducing the overall number of signal lines needed and simplifying the routing structure.
2Area of stationary object
If a sensor array is used for large touch panels, then the sensing area is increased, but power consumption increases
Solution Approach 1:
The sensor array is divided into multiple sensor groups that can be independently controlled. This allows the controller to activate only the sensor groups currently needed for touch detection, reducing the overall power consumption while maintaining large sensing area capability.
Solution Approach 2:
The system employs periodic scanning of sensor groups through control signals that sequentially activate different groups. This periodic activation pattern reduces average power consumption compared to continuous activation of all sensors, while still providing comprehensive touch detection coverage.
3Measurement precision
If individual signal lines are used for each sensor, then sensing precision is improved, but the number of signal lines and routing complexity increase
Solution Approach 1:
Sensors are grouped into sensor groups where sensors within each group share common signal lines. This segmentation maintains sufficient sensing precision for each group while significantly reducing the total number of signal lines required compared to individual line connections.
Solution Approach 2:
Switch circuits are introduced as intermediary components between sensor groups and the controller. These switches enable multiple sensor groups to share common signal lines by dynamically connecting the appropriate group to the active signal line, reducing routing complexity while preserving sensing precision.
Data Source
AI summary
An apparatus for sensing a touch includes: a sensor array including a plurality of sensor groups, each of the plurality of sensor groups including sensors adjacent to each other; a first switch circuit configured to connect each of the plurality of sensor groups to a first channel or a second channel according to a first control signal; and a second switch circuit configured to select one of the first channel and the second channel according to a second control signal, wherein the first channel includes first signal lines connected to respective sensors included in a first sensor group of the plurality of sensor groups by the first switch circuit, and the second channel includes a second signal line commonly connected to the sensors included in the first sensor group by the first switch circuit.