Piezoelectric Force Sensing in Touch Device Stacks
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Solution Overview
Problem
Touch devices primarily rely on positional input, limiting user interaction to x-, y-positioning, and lack additional input modes beyond positional constraints, which restricts the range of user interactions and applications.
Innovation Solution
Incorporating piezoelectric sensors into touch devices to detect force applied, allowing for additional input modes by using deformable device stacks and piezoelectric elements that generate signals representative of the applied force, enabling force sensing in conjunction with capacitive touch sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If piezoelectric sensors are integrated into touch devices, then force detection capability is improved, but device complexity increases
Solution Approach 1:
The piezoelectric sensor is integrated within the existing touch display stack, merging force sensing functionality with the touch sensing structure. The sensor is positioned between layers of the display stack (such as between the touch sensor and liquid crystal display layers), allowing force detection without adding a completely separate external component system.
Solution Approach 2:
The piezoelectric sensor serves multiple functions: it detects force applied to the display surface, generates electrical signals from mechanical deformation, and can work in conjunction with existing capacitive touch sensors to provide both position and force information through a unified sensing system.
2Measurement precision
If piezoelectric elements are added to detect force, then measurement precision for force is improved, but manufacturing complexity increases
Solution Approach 1:
The piezoelectric element's physical state changes in response to applied force, transforming mechanical stress into electrical signals through the piezoelectric effect. This parameter change enables precise force measurement while allowing the sensor to be manufactured as part of the display stack using existing thin-film fabrication processes.
Solution Approach 2:
The piezoelectric sensor is nested within the existing touch display stack structure, positioned between functional layers such as the touch sensor and liquid crystal display. This nested configuration allows the sensor to utilize existing manufacturing infrastructure and assembly processes without requiring entirely separate production lines.
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 enhanced user interaction capabilities by allowing users to differentiate between lighter and more forceful touches, expanding the range of inputs that can be detected and processed by touch devices, thereby increasing their functionality.
Implementation Method 1
a piezoelectric element positioned relative to the deformable device stack such that the piezoelectric element deforms with the deformable stack. Deformation of the piezoelectric element generates a signal having a magnitude discernable as representative of an amount of force applied to the touch device.
Data Source
AI summary
Systems and methods related to piezoelectric based force sensing in touch devices are presented. One embodiment, for example, may take the form of an apparatus including a touch device having a deformable device stack and a piezoelectric element positioned relative to the deformable device stack such that the piezoelectric element deforms with the deformable stack. Deformation of the piezoelectric element generates a signal having a magnitude discernable as representative of an amount of force applied to the touch device.