Capacitive Data Entry Device with Conductive Traces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing data-entry systems, particularly for visually impaired individuals, face challenges in securely and efficiently entering confidential information on touch panels due to the lack of tactile feedback and increased costs associated with physical keypads, which also pose security risks and aesthetic concerns.
Innovation Solution
A capacitive data-entry device with a matrix of electrodes and a network of conductive tracks that prevents recalibration of the touch panel, allowing for secure and ergonomic entry of information by detecting the device's orientation and position on the touch panel, eliminating the need for physical keypads and reducing reliance on third-party assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a physical keypad is provided for visually impaired persons, then ease of operation is improved, but device complexity and cost increase
Solution Approach 1:
A protective sheet with conductive traces is introduced as an intermediary between the user and the touch panel. This sheet provides tactile feedback through raised conductive traces that form a virtual keypad, enabling visually impaired users to locate keys by touch while the actual key presses are detected capacitively by the touch panel beneath, thus avoiding the need for a separate physical keypad device
Solution Approach 2:
The patent replaces the mechanical switch-based physical keypad with a capacitive touch detection system. The conductive traces on the protective sheet create capacitive coupling with the touch panel electrodes, allowing key detection through electrical field changes rather than mechanical contact, thereby eliminating the need for separate mechanical switching components
2Ease of operation
If a physical keypad is provided for visually impaired persons, then ease of operation is improved, but manufacturing cost increases
Solution Approach 1:
The protective sheet serves multiple functions simultaneously: it protects the touch panel from damage, provides tactile guidance for visually impaired users through raised conductive traces, and acts as the input interface itself by detecting capacitive changes. This multi-functionality eliminates the need for separate physical keypads, reducing overall manufacturing costs while maintaining accessibility
Solution Approach 2:
The patent changes the physical parameters of the protective sheet by incorporating conductive traces with specific capacitance values and raising them to create tactile feedback. These parameter changes enable the sheet to provide both protective and interactive functions using the same base material, avoiding the need for additional expensive components
3Measurement precision
If the touch panel is recalibrated to remove noise, then measurement precision is improved, but the contact pad detection capability deteriorates
Solution Approach 1:
The system dynamically adjusts its detection parameters based on the operational context. When the protective sheet is detected, the system switches to a detection mode that recognizes the capacitive signature of the sheet's conductive traces rather than using fixed recalibration thresholds, allowing continuous operation without losing contact pad detection capability
Solution Approach 2:
The system uses feedback from the capacitive scanning process to identify the presence of the protective sheet and adjust its detection algorithm accordingly. By monitoring the capacitive values and their patterns, the system can distinguish between the protective sheet's traces and actual user inputs, maintaining both noise filtering and contact pad detection reliability
4Reliability
If random display of virtual keypad is used, then security is improved, but ease of operation deteriorates
Solution Approach 1:
The protective sheet provides localized tactile quality through raised conductive traces at specific key positions, creating a consistent tactile map that remains the same regardless of how the virtual keypad is displayed on the screen. This allows visually impaired users to rely on local tactile cues rather than needing to see or remember the global layout of the virtual keypad
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 simple, secure, and ergonomic data entry for visually impaired individuals and others, reducing costs and security risks while maintaining the aesthetic appeal of touch panels, as the device prevents recalibration and ensures accurate detection of user inputs without visible finger marks or additional noise.
Implementation Method 1
a capacitive touch panel comprising electrodes in rows and columns forming a matrix of electrodes comprising nodes and being managed by a control unit configured to carry out cycles of capacitive scanning and measurement of variance of capacitance of the nodes relative to reference values
Implementation Method 2
the network of conductive tracks having a capacitance such that it is not detected as exerting a meaningful touch and occupying a surface area that is, on the one hand, greater than the surface area occupied by said at least one contact pad and, on the other hand, sufficient so that, during the capacitive scanning cycles, the network of conductive tracks interacts with several nodes of the matrix of electrodes in the form of charges that travel back and forth in the network of conductive tracks
Data Source
AI summary
A system of data entry includes a touch panel of a terminal and a data-entry device to be placed on the touch panel. The touch panel includes a matrix of electrodes having nodes and is managed by a control unit configured carrying out cycles of capacitive scanning and measurement of variance of capacitance of the nodes relative to reference values, detecting meaningful touches on the touch panel and recalibrating reference values. The device includes a plate having a lower face for placing the device on the touch panel; and an upper face with a matrix of entry zones having a thickness enabling a detection of a finger by the touch panel; a flat contact pad electrically conductive and fixedly attached to the lower face; and a network of conductive tracks stretching over at least a part of the upper face and being electrically connected to the contact pad.