Piezoelectric Capacitor Assembly for Large-Area Touch and Haptics
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Solution Overview
Problem
Existing systems fail to effectively enable touch-sensing over larger areas and concurrently perform force-measuring and haptic functionalities, which are desirable in various applications including MEMS chips with piezoelectric micromechanical ultrasonic transducers.
Innovation Solution
A system comprising a piezoelectric capacitor assembly with piezoelectric force-measuring elements and ultrasonic transducers, coupled with signal processing circuitry, allowing configuration as force-measuring, touch-sensing, and haptic functionalities, and integrated into a cover layer for expanded sensing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a typical MEMS chip with PMUT array is used for touch-sensing, then touch-sensing capability is provided, but the sensing area is limited to the lateral area of the MEMS chip
Solution Approach 1:
The piezoelectric capacitor assembly is designed to perform multiple functions including force-measuring, touch-sensing, and haptic functionalities through configurable piezoelectric force-measuring elements and ultrasonic transducers, allowing a single device to replace multiple separate components and enable comprehensive interaction capabilities across the sensing area
Solution Approach 2:
The piezoelectric member is divided into multiple piezoelectric capacitors located at respective lateral positions, with each capacitor capable of independent configuration as force-measuring elements or ultrasonic transducers, enabling distributed sensing across a larger area while maintaining individual functional control
2Adaptability or versatility
If separate components are used for force-measuring, touch-sensing, and haptic functionalities, then each function can be optimized, but device complexity increases
Solution Approach 1:
Multiple functional elements (piezoelectric force-measuring elements and ultrasonic transducers) are integrated into a single piezoelectric capacitor assembly with a common piezoelectric member, reducing the number of separate components and simplifying the overall system architecture while maintaining all required functionalities
Solution Approach 2:
The piezoelectric capacitor assembly is designed to perform multiple functions including force-measuring, touch-sensing, and haptic functionalities through configurable piezoelectric force-measuring elements and ultrasonic transducers, allowing a single device to replace multiple separate components and enable comprehensive interaction capabilities
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 accurate touch detection and force measurement over larger areas, distinguishing between different touch events, and providing haptic feedback, enhancing the functionality of devices such as smartphones and keyboards.
Implementation Method 1
The piezoelectric capacitors include piezoelectric force-measuring elements (PFEs). The PFEs are configured to output voltage signals between the respective first electrode and the respective second electrode in accordance with a time-varying strain at the respective portion of the piezoelectric member between the respective first electrode and the respective second electrode resulting from a low-frequency mechanical deformation.
Implementation Method 2
a PMUT can be configured as a transmitter (ultrasonic transmitter) or a receiver (ultrasonic receiver). Accordingly, a MEMS chip containing a PMUT array can be configured to sense touch.
Implementation Method 3
a PMUT can be configured as a transmitter (ultrasonic transmitter) or a receiver (ultrasonic receiver). Accordingly, a MEMS chip containing a PMUT array can be configured to sense touch.
Data Source
AI summary
A system includes a piezoelectric capacitor assembly and signal processing circuitry coupled to the piezoelectric capacitor assembly. The piezoelectric capacitor assembly includes a piezoelectric member and piezoelectric capacitors located at respective lateral positions along the piezoelectric member. Each piezoelectric capacitor includes: (1) a respective portion of the piezoelectric member, (2) a first electrode, and (3) a second electrode. The first and second electrodes are positioned on opposite side of the piezoelectric member. The piezoelectric capacitors include piezoelectric force-measuring elements (PFEs). The PFEs are configured to output voltage signals between the respective first electrode and the respective second electrode in accordance with a time-varying strain at the respective portion of the piezoelectric member between the respective first electrode and the respective second electrode resulting from a low-frequency mechanical deformation. The signal processing circuitry is configured to read at least some of the PFE voltage signals.