Electrostatic Microvalve Structure for Low-Power Fluid Discharge
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Solution Overview
Problem
Existing valve elements driven by electrostatic attractive force face challenges in achieving miniaturization and low power consumption while maintaining good fluid discharge characteristics, and their manufacturing process is complicated due to the need for accurate wafer alignment and dual-surface wiring.
Innovation Solution
A valve element configuration with a first and second movable electrode portion separated by a spacer, supported by a frame, allowing for increased electrode distance using electrostatic attraction without increasing voltage, and manufactured through thin film layering on a single semiconductor substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the distance between electrodes is increased to improve fluid discharge characteristics, then fluid discharge efficiency is improved, but the electrostatic attractive force becomes remarkably weak
Solution Approach 1:
The patent changes the physical parameters of the electrode structure by introducing a frame portion that supports the first movable electrode portion at a predetermined distance from the second movable electrode portion. This structural parameter change allows maintaining a larger inter-electrode distance for improved fluid discharge while the frame provides mechanical support to preserve the electrostatic attractive force necessary for valve operation.
Solution Approach 2:
The patent transitions from a planar electrode structure to a three-dimensional structure by adding a frame portion that extends in the vertical dimension. This dimensional change allows the first movable electrode portion to be supported at a predetermined distance from the second movable electrode portion, enabling simultaneous optimization of fluid discharge characteristics and electrostatic attractive force.
2Force
If the electrode area is increased to strengthen the electrostatic attractive force, then the driving force for the valve is improved, but the valve element size increases
Solution Approach 1:
The patent changes the structural parameters by introducing a frame portion that provides mechanical support, allowing the electrode area to be reduced while maintaining sufficient electrostatic attractive force. The frame's structural support compensates for the reduced electrode area, enabling miniaturization without sacrificing driving force.
Solution Approach 2:
The patent segments the valve element into distinct functional components: a frame portion for mechanical support, a first movable electrode portion for electrostatic actuation, and a second movable electrode portion for sealing. This segmentation allows optimization of each component's function independently, reducing overall size while maintaining performance.
3Force
If the applied voltage is increased to strengthen the electrostatic attractive force, then the driving force for the valve is improved, but the power consumption increases
Solution Approach 1:
The patent changes the structural parameters by introducing a frame portion that provides mechanical support, allowing the electrostatic attractive force to be maintained at lower applied voltages. The frame's structural support enables the valve to operate with reduced power consumption while preserving sufficient driving force for valve actuation.
4Productivity
If two semiconductor substrates are bonded together to form a normally closed microvalve, then good fluid discharge characteristics are achieved, but the manufacturing process becomes complicated
Solution Approach 1:
The patent merges multiple functions into a single semiconductor substrate structure. The frame portion, first movable electrode portion, and second movable electrode portion are all formed on one substrate, eliminating the need for bonding two substrates together. This simplifies the manufacturing process while maintaining good fluid discharge characteristics.
Solution Approach 2:
The single semiconductor substrate serves multiple functions: it provides the frame structure for mechanical support, forms the first movable electrode portion for electrostatic actuation, and supports the second movable electrode portion for sealing. This multi-functionality eliminates the need for substrate bonding while achieving the desired fluid discharge characteristics.
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 configuration enables miniaturization and low power consumption with improved fluid discharge characteristics, facilitated by a simple manufacturing process.
Implementation Method 1
an electrostatic attractive force is generated by applying a voltage to each electrode of the two electrode portions
Data Source
AI summary
Valve element for controlling flow of fluid, including: a first movable electrode portion including a fluid introduction port through which the fluid flows; a second movable electrode portion including a discharge port through which the fluid is discharged, the second movable electrode portion being disposed to cover the fluid introduction port, with an interval between the second movable electrode portion and the first movable electrode portion; a spacer portion configured to secure the interval between the first movable electrode portion and the second movable electrode portion; and a frame portion configured to form a back chamber that communicates with the fluid introduction port and configured to support the first movable electrode portion, wherein the first movable electrode portion and the second movable electrode portion can be drawn together by an electrostatic attractive force generated by applying a voltage to the first and second movable electrode, sealing the fluid introduction port.