Dynamic Channel Assignment in Touch Sensors for Signal Separation
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Solution Overview
Problem
Existing touch sensors struggle to distinguish between touch points generated by different hands, users, or objects with high accuracy and low latency, particularly in capacitive touch sensors using multiplexing schemes like FDM and CDM, leading to interference and false measurements.
Innovation Solution
Implement orthogonal signaling in capacitive touch sensors using frequency-division multiplexing (FDM), code-division multiplexing (CDM), or hybrid modulation techniques to separate and distinguish touch signals, combined with low-latency signal processing and optical sensing methods, enabling dynamic channel assignment and interference reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiplexing schemes (FDM/CDM) are used to increase scan rate, then productivity is improved, but measurement precision deteriorates due to signal interference
Solution Approach 1:
The touch sensor surface is divided into multiple independent zones, each with its own dedicated signal channels. This segmentation allows simultaneous scanning of multiple zones without signal interference, maintaining high scan rates while improving measurement precision through spatial separation of measurement paths.
Solution Approach 2:
A signal processing intermediary layer is introduced that dynamically assigns and manages communication channels between touch zones and processing units. This intermediary optimizes signal routing and reduces interference by coordinating channel usage across multiple multiplexed zones.
2Measurement precision
If dynamic channel assignment is implemented to reduce interference, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system employs dynamic channel assignment where signal pathways are adaptively configured based on current touch conditions. Channels are reassigned in real-time to optimize measurement precision for active touch zones while reducing complexity by deactivating or simplifying pathways for inactive zones.
Solution Approach 2:
The system performs preliminary channel configuration and signal pathway setup before touch events occur. By pre-establishing optimal signal routes and assigning channels in advance based on predicted touch patterns, the system reduces the complexity of real-time decision-making during actual touch measurement.
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 solution effectively differentiates touch points with high accuracy and low latency, reducing interference and enabling robust, economical manufacturing of touch-sensitive devices, including transparent displays.
Implementation Method 1
combined with low-latency signal processing and optical sensing methods
Data Source
AI summary
Methods are disclosed for dynamic assignment of possible channels in a touch sensitive device having rows and columns. In an embodiment, a method determines a first signal space in which to generate signals for use in the touch sensor. Signals are then generated in the first signal space on separate ones of the rows and a column signal is sensed on a column. The first signal space is replaced with a second signal space, and a second plurality of signals is generated for use in the touch sensor in the second frequency space. The second plurality of signals is sensed to identify a touch event in the touch sensitive device.