Virtual Deformation for Force-Sensing Touch Screens
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Force-sensing touch screens face non-linearity issues when sufficient force is applied, causing deformation that interferes with algorithms relying on linear responses, particularly when the screen contacts device components or rough surfaces, leading to inaccurate force detection and location identification.
Innovation Solution
A method and system that measure actual deformation and sensed force using a deformation sensing layer and residual force sensor, with a processor determining expected deformation based on applied force and subtracting counter-force effects to calculate virtual deformation, ensuring linear response and accurate force detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sufficient force is applied to the touch screen, then force detection capability is improved, but the deformation becomes non-linear due to contact with internal components
Solution Approach 1:
The patent replaces the direct mechanical measurement of deformation with an optical measurement system. By using optical interferometry to measure the actual deformation of the touch screen, the system can accurately detect force-induced deformation without being affected by the mechanical contact with internal components that causes non-linearity. This substitution allows the system to maintain measurement accuracy while operating in the non-linear regime.
Solution Approach 2:
The patent changes the measurement parameter from assuming linear deformation to measuring actual deformation. By using optical interferometry to directly measure the displacement of the touch screen surface, the system can capture the true deformation state regardless of whether it is linear or non-linear. This parameter change enables accurate force detection even when the deformation-nonlinear relationship occurs due to contact with internal components.
2Adaptability or versatility
If the touch screen deforms to contact internal components, then force sensing range is extended, but algorithm accuracy deteriorates due to non-linear response
Solution Approach 1:
The patent replaces algorithm-based force reconstruction with direct optical measurement. Instead of using algorithms that assume linear deformation to reconstruct force from deformation data, the system uses optical interferometry to directly measure the deformation with high precision. This substitution eliminates the dependency on linear assumptions and maintains algorithm accuracy across the extended force sensing range.
Solution Approach 2:
The patent implements a feedback mechanism where the measured deformation data is used to correct the force sensing calculations. By continuously monitoring the actual deformation through optical measurement and comparing it with the expected linear deformation, the system can identify when non-linear effects occur and adjust its calculations accordingly, maintaining accuracy across the full sensing range.
3Strength
If rough surfaces or protrusions are present in contacted portions, then structural support is provided, but deformation uniformity deteriorates
Solution Approach 1:
The patent replaces assumptions about uniform deformation with direct optical measurement of actual deformation. The optical interferometry system measures the deformation at each point on the touch screen surface, capturing the non-uniform deformation patterns caused by rough surfaces or protrusions. This allows the system to accurately detect force even when deformation uniformity deteriorates due to structural support features.
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
Restores linearity in force-deformation relationships, enabling accurate detection and separation of multiple forces, and corrects for non-linearities caused by internal obstructions, allowing standard algorithms to interpret forces effectively.
Implementation Method 1
The deformation sensing layer can be an air gap or other compressible system and configured to operate as a capacitance sensor, and measuring the actual deformation can comprise measuring capacitance across the compressible deformation sensing layer
Data Source
AI summary
A force applied to a force-sensing touch screen device may be determined as follows. A deformation sensing layer of the device may measure an actual deformation of a touch screen of the device. A force sensor of the device may measure a sensed force applied by the touch screen to the force sensor of the device. A processor circuit of the device may determine an expected deformation expected to be imparted to the touch screen by the sensed force. The processor circuit may determine a virtual deformation based on the expected deformation due to the sensed force and the measured actual deformation. The virtual deformation may indicate the force applied to the force-sensing touch screen.