Transparent Force Sensing Touch Screen with Resistance Scanning
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Solution Overview
Problem
Existing multi-touch force-sensing touch-screen displays are cost-prohibitive and slow due to their complexity, requiring multiple scans of each pixel for every frame, making them unsuitable for certain applications.
Innovation Solution
A low-cost, easy-to-manufacture analog touch sensing display system using a touch panel with conductive patterns and a transparent force sensing sheet, where the system determines force location and magnitude by scanning resistance across the sheets, allowing for fast touch detection and adaptation for signature capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-touch force-sensing touch-screen displays use two sets of perpendicular electrodes arranged on opposite surfaces of a transparent force sensing layer, then multi-touch sensing capability and simultaneous force detection are achieved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent extracts only the essential force-sensing functionality from complex multi-touch technology. Instead of implementing full multi-touch capability with multiple electrode sets, the invention uses a single transparent force sensing layer with simplified electrode configuration, taking out only the core force detection feature while eliminating unnecessary complexity for full multi-touch support.
Solution Approach 2:
The patent employs cost-effective materials and manufacturing approaches for the transparent force sensing layer. By using readily available transparent conducting materials and standard fabrication processes rather than specialized multi-touch components, the solution achieves force sensing at a fraction of the cost of full multi-touch displays.
2Measurement precision
If multi-touch displays scan each pixel multiple times for every frame, then accurate force detection is achieved, but response speed decreases making the display slow
Solution Approach 1:
The patent performs preliminary scanning of the force sensing layer to establish baseline resistance values before actual touch detection. This pre-scanning allows the system to quickly compare subsequent measurements against known references, achieving accurate force detection without requiring multiple slow scans per frame, thereby improving response speed while maintaining precision.
Solution Approach 2:
Instead of scanning every pixel multiple times for each frame, the patent implements periodic scanning at optimized intervals. The system scans the force sensing layer at specific periods based on touch dynamics, performing frequent scans only when touch events are detected and using less frequent scans during idle periods, thus balancing accuracy requirements with speed requirements.
3Measurement precision
If a transparent force sensing layer with variable resistance is used to detect contact force, then force magnitude detection is achieved, but the system requires complex scanning and control mechanisms
Solution Approach 1:
The patent replaces complex mechanical scanning mechanisms with electrical measurement techniques. Instead of physically scanning the force sensing layer with moving components, the system uses electrical resistance measurements through the transparent force sensing layer to detect force magnitude, substituting mechanical complexity with simpler electrical sensing that leverages the inherent variable resistance properties of the TFS material.
Solution Approach 2:
The transparent force sensing layer inherently provides its own sensing mechanism through its variable resistance property. The material itself changes resistance in response to applied force, eliminating the need for external sensing elements or complex control mechanisms. The system leverages the self-changing electrical properties of the TFS layer to provide force detection without requiring additional active components.
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 system provides a cost-effective, fast, and accurate touch detection solution suitable for single-touch applications, improving manufacturing efficiency and reducing the complexity of control systems, enabling efficient signature capture and potentially supporting multi-touch gestures.
Implementation Method 1
A transparent force sensing (TFS) sheet having opposed major surfaces and a variable resistance may be situated between the first and second sheets
Data Source
AI summary
A touch-screen display apparatus, the apparatus may include first and second sheets having opposed major surfaces and a size and shape defined by a periphery. The periphery may be defined by opposed ends and opposed edges. The first and second sheets may each have a conductive pattern including a pair of opposed busbars and a plurality of traces electrically coupled to, and extending between, corresponding pairs of opposed busbars. The transparent force sensing (TFS) sheet may have opposed major surfaces and a variable resistance which is related to a force exerted upon one or more of its major surfaces. The TFS sheet may be situated between the first and second sheets. The apparatus may also include one or more separation portions situated between the TFS sheet and the first or second sheet to bias the TFS sheet apart from the first or second sheet.