Normally Closed Piezoelectric Microvalve for Low-Leakage Flow Control
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Solution Overview
Problem
Microvalves used in microfluidic applications often consume high electrical power and are prone to leakage due to the need for constant voltage application, making them unsuitable for portable and wearable devices, as well as small form factor implementations like in-ear headphones or lab-on-a-chip systems.
Innovation Solution
A piezoelectric valve is designed to be biased in a normally closed configuration without an external power source, utilizing a piezoelectric-based actuation layer that retains compressive film stress to maintain closure, reducing power consumption and leakage, and can be actuated open with an external power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant voltage is applied to keep microvalve closed, then leakage is prevented, but electrical power consumption increases
Solution Approach 1:
The piezoelectric actuator layer serves itself by retaining compressive film stress to automatically maintain the valve closed configuration without requiring continuous external power input. The stored mechanical stress in the piezoelectric layer provides the closing force, eliminating the need for continuous electrical power to prevent leakage.
Solution Approach 2:
Instead of continuous voltage application, the system uses periodic or pulsed electrical input only when valve opening is required. The piezoelectric actuator receives electrical signals temporarily to open the valve, then returns to its stress-retained closed state automatically, converting continuous power consumption into periodic action.
2Use of energy by moving object
If piezoelectric actuator layer is designed to retain compressive film stress for normally closed configuration, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The piezoelectric actuator layer combines multiple functions: it serves as both the actuation mechanism and the stress-retaining element that provides the closing force. By merging the actuator and the biasing mechanism into a single integrated layer, the design reduces overall device complexity despite the sophisticated stress retention capability.
Solution Approach 2:
The piezoelectric actuator layer utilizes changes in physical parameters (electrical voltage, mechanical stress, dimensional deformation) to achieve valve control. By changing the electrical state of the piezoelectric material, the system transitions between closed (stress-retained) and open configurations, enabling complex functionality through parameter modulation rather than complex mechanical structures.
3Adaptability or versatility
If microvalve is designed for portable applications with small form factor, then adaptability improves, but power consumption constraints increase
Solution Approach 1:
The piezoelectric valve serves itself by using the retained compressive film stress in the piezoelectric actuator layer to maintain its closed configuration without continuous external power. This self-biasing mechanism is particularly suited for portable applications where power resources are limited, enabling the small form factor device to operate adaptively with minimal power consumption.
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 valve operates with reduced power consumption and minimized leakage, making it suitable for portable and small form factor applications by maintaining a closed configuration without continuous power input.
Implementation Method 1
A piezoelectric valve includes a valve body and a valve vane coupled with the valve body, where a compressive film stress in one or more layers of the valve body biases the valve vane against the valve body in a normally closed configuration without an external power source.
Implementation Method 2
The compressive film stress in the piezoelectric-based actuation layer may be retained through formation of the piezoelectric-based actuation layer with a first electrode and a second electrode, where the compressive film stress is retained through a thickness of the piezoelectric-based actuation layer.
Data Source
AI summary
A piezoelectric valve may be formed using semiconductor processing techniques such that the piezoelectric valve is biased in a normally closed configuration. Actuation of the piezoelectric valve may be achieved through the use of a piezoelectric-based actuation layer of the piezoelectric valve. The piezoelectric valve may be implemented in various use cases, such as a dispensing valve for precise drug delivery, a relief valve to reduce the occlusion effect in speaker-based devices (e.g., in-ear headphones), a pressure control valve, and/or another type of valve that is configured for microfluidic control, among other examples. The normally closed configuration of the piezoelectric valve enables the piezoelectric valve to operate as a normally closed valve with reduced power consumption.