Piezoelectric Sensor Embedded in Portable Card for Power-Free Input
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Solution Overview
Problem
Conventional portable cards with mechanical domes or membrane switches face issues such as power consumption during operation, deformation leading to power depletion, and production defects, as well as a lack of power-free deformation sensing mechanisms.
Innovation Solution
A portable card equipped with a piezoelectric sensing means that generates power upon deformation, allowing the card to transition between modes without a power source, and is integrated within the card's structure to maintain a flat surface and prevent production defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical domes or membrane switches are used for user input, then the card can be operated to activate the processor, but the switches require current flow during operation and may deplete the power source
Solution Approach 1:
The patent replaces mechanical dome switches and membrane switches with a piezoelectric sensing means. The piezoelectric element converts mechanical deformation directly into electrical signals without requiring continuous current flow, thereby eliminating the power consumption issue associated with conventional mechanical switches while maintaining user input capability.
Solution Approach 2:
The piezoelectric sensing means generates its own electrical signal from the mechanical deformation applied by the user. This self-generating capability means the sensor does not require external power to operate, allowing the processor to remain in sleep mode and conserve battery power while still enabling user interaction when needed.
2Ease of operation
If mechanical domes are used on the card surface, then user input is enabled, but the domes extend from the flat surface and may be rendered useless by production/lamination processes
Solution Approach 1:
The piezoelectric sensing means is embedded within the card structure, nested between the front and back protective layers. This integration allows the sensing element to be fully contained within the card's flat profile, eliminating the need for protruding domes and making the card compatible with standard production and lamination processes while preserving tactile input functionality.
3Speed
If the processor operates continuously to respond to user input, then immediate response is possible, but power consumption increases
Solution Approach 1:
The processor operates in periodic cycles rather than continuously. It alternates between sleep mode (low power consumption) and active mode (processing user input). The piezoelectric sensor triggers the processor to wake from sleep mode only when deformation is detected, enabling immediate response to legitimate user input while conserving power during idle periods.
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 piezoelectric sensor enables power-efficient operation by awakening the processor only when needed, reducing accidental activations through sensitivity adjustment, and allowing for embedded, deformation-based functionality without external power consumption.
Implementation Method 1
The sensor (14) is a piezo electric element in that this additionally has the ability to provide power when deformed or bent
Data Source
Figure 1~3
AI summary
A portable card, such as a credit card, having therein electronics, such as a processor, and a deformable switching element or sensor, where the deformation or bending of the sensor/switch is determined and used for controlling the electronics. In one aspect, bending of a piezo element provides power for bringing a processor out of a sleep mode.