Flexible 3D Display Touch Sensing with Strain-Capacitance Feedback
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Solution Overview
Problem
Existing display devices struggle to accurately detect touch inputs on flexible and deformable surfaces, particularly in three-dimensional configurations, due to the challenges of sensing deformations and capacitance changes effectively.
Innovation Solution
Incorporation of strain sensors and touch electrodes in a display device, with a touch detector that senses touch inputs by comparing measured elongation rates and capacitance of sub-areas to reference data, utilizing a Wheatstone bridge configuration and serpentine conductive lines to enhance sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain sensors and touch electrodes are integrated in the display area, then touch input detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines strain sensors and touch electrodes into a single integrated structure within the display area. The strain sensors are positioned to detect deformation of the flexible substrate, while touch electrodes detect capacitive changes from finger contact. This merging allows simultaneous measurement of both mechanical deformation and electrical capacitance, improving touch detection accuracy without requiring separate sensor systems.
Solution Approach 2:
The display device structure serves multiple functions: it acts as both the display surface and the sensor substrate. The flexible substrate itself becomes the sensing element for strain sensors, while the same substrate deformation affects touch electrode capacitance. This multi-functionality reduces the need for additional dedicated sensor layers, thereby improving measurement precision without proportionally increasing device complexity.
2Adaptability or versatility
If the display device is made flexible and deformable, then adaptability is improved, but measurement precision of touch inputs deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the touch detector measures both the capacitance of touch electrodes and the deformation of strain sensors, then uses this combined information to compensate for measurement errors. By continuously monitoring substrate deformation through strain sensors and adjusting touch detection algorithms accordingly, the system maintains high measurement precision even when the flexible substrate is deformed into various three-dimensional shapes.
Solution Approach 2:
The system dynamically adjusts detection parameters based on substrate deformation state. When the flexible display is deformed, the strain sensors detect the deformation magnitude and direction, and the touch detector modifies its capacitance measurement thresholds and sensitivity settings accordingly. This parameter adjustment compensates for the effects of flexibility-induced deformation, maintaining touch detection accuracy across different display configurations.
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 precise detection of touch inputs on deformable display surfaces by accounting for three-dimensional deformations, improving user interaction capabilities in flexible and stretchable display devices.
Implementation Method 1
strain sensors in the display area...sense a touch input based on a relationship between an elongation rate and capacitance
Implementation Method 2
touch electrodes...measured capacitance of the touch electrodes corresponding to the sub-areas
Data Source
AI summary
A display device includes a substrate, light-emitting elements above the substrate, and defining a display area capable of providing a three-dimensional image plane, a touch layer above the light-emitting elements, and including touch electrodes, strain sensors in the display area, and a touch detector electrically connected to the touch layer and to the strain sensors, and configured to sense a touch input based on a relationship between an elongation rate and capacitance of the display area.