Projected Capacitive Touch Sensing for Multi-User Ghost Rejection
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Solution Overview
Problem
Existing projected capacitive touch (PCAP) sensors struggle to accurately distinguish between multiple concurrent touches from different users, leading to ghosting and interference in multi-user multi-touch interactions.
Innovation Solution
The system determines whether concurrent touches share anti-ghosts, associating them with a common touch entity based on shared anti-ghosts, and initiates appropriate interaction modes for multi-user multi-touch functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the touch sensor uses traditional PCAP technology to detect multiple concurrent touches, then multi-touch functionality is enabled, but ghosting and interference occur when multiple users touch simultaneously
Solution Approach 1:
The patent segments the touch detection process by introducing separate sensing arrays for different users, allowing independent detection of touches from different users. This segmentation enables the system to distinguish between genuine touches and ghosting effects by analyzing signals from multiple independent sensing arrays simultaneously.
Solution Approach 2:
The patent introduces an intermediary processing layer that analyzes capacitance changes across multiple sensing arrays to distinguish between real touches and ghosting effects. This intermediary processing layer correlates signals from different arrays to identify genuine touch events while filtering out interference.
2Productivity
If the touch sensor attempts to detect all concurrent touches without user differentiation, then multi-touch functionality is provided, but interference between different users' touches increases
Solution Approach 1:
The patent segments touch detection by implementing separate sensing arrays positioned to detect touches from different users independently. This allows the system to process touches from multiple users simultaneously without interference, as each sensing array captures signals specific to its designated user zone.
Solution Approach 2:
The patent applies local quality by optimizing each sensing array's characteristics for its specific user zone. Each sensing array is configured with local parameters tailored to detect touches from a particular user, improving overall system performance while minimizing cross-user interference.
3Device complexity
If the touch sensor uses a single sensing array to detect multiple touches, then device complexity is reduced, but the ability to differentiate between different users' touches is compromised
Solution Approach 1:
The patent divides the sensing system into multiple independent sensing arrays, each responsible for detecting touches from a specific user. This segmentation improves measurement precision by allowing each array to be optimized for its designated user, while the overall system complexity remains manageable through modular architecture.
Solution Approach 2:
The patent implements multi-functionality by designing sensing arrays that can simultaneously serve multiple purposes: detecting touches from their primary user, providing ghosting detection for adjacent users, and contributing to overall multi-touch functionality. This universal approach enhances differentiation capability 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
Enhances the ability of touch sensors to differentiate between touches from different users, enabling accurate multi-user multi-touch interactions and improving the reliability of touch-based inputs.
Implementation Method 1
Projected capacitive touch (PCAP) technology uses electric fields from embedded electrodes projected through glass layers that are influenced by finger touches with the result of changes in measured capacitances
Data Source
AI summary
Techniques for providing multi-user multi-touch projected capacitive touch sensors are disclosed herein. Some embodiments may include a method that includes receiving a first sense signal from a first sensing array, the first sensing array configured to provide the first sense signal indicating a first touch on a first touch surface of a touch substrate as well as receiving a second sense signal from a second sensing array, the second sensing array configured to provide the second sense signal indicating a second touch on a second touch surface of a second touch substrate occurring concurrently to the first touch. The method may further include determining whether the first touch and the second touch share at least one anti-ghost. The method may also include associating the first touch and the second touch with a common touch entity in response to determining that the first touch and the second touch share the at least one anti-ghost.