MEMS Check Valve Structure With Bubble-Driven Fluid Ejection
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Solution Overview
Problem
Current microfluidic systems face challenges in designing efficient check valves and unidirectional pumps for micro electromechanical systems (MEMS) due to complexities in fabrication and fluid control within microfluidic devices.
Innovation Solution
A fluidic MEMS device is developed with a check valve leaf that pivots about a nonparallel axis, utilizing a 'living hinge' and a resistive device to create a bubble for fluid ejection and control, integrated within a single unitary layer, facilitating fabrication and operation as part of a microfluidic system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional check valves and unidirectional pumps are designed for microfluidic systems, then fluid control functionality is achieved, but fabrication complexity and device design difficulty increase significantly
Solution Approach 1:
The patent combines the check valve leaf, pivot axis, and bubble generation chamber into a single integrated structure formed from one continuous layer of photoresist material. This merging eliminates the need for separate fabrication steps for multiple components, reducing overall device complexity while maintaining reliable fluid control functionality through the integrated design.
Solution Approach 2:
The single unitary layer structure serves multiple functions simultaneously: it forms the check valve leaf for unidirectional flow control, provides the pivot axis for valve operation, creates the bubble generation chamber for fluid ejection, and acts as the structural substrate. This multi-functionality reduces the number of fabrication steps and components needed.
2Manufacturing precision
If multiple layers and components are used to create check valves and pumps, then fluid control precision is improved, but manufacturing difficulty and fabrication steps increase
Solution Approach 1:
The invention merges multiple functional components into a single layer of photoresist material that is patterned using standard photolithography techniques. The check valve leaf, pivot axis, and bubble chamber are all formed in one layer, allowing precise fluid control to be achieved through a single fabrication process rather than requiring multiple layered structures.
Solution Approach 2:
The patent utilizes the physical and chemical properties of photoresist material, which can be precisely patterned through photolithography. By changing the material state from liquid photoresist to solidified structured layer through UV exposure and development, the invention achieves high manufacturing precision using standard semiconductor fabrication techniques.
3Ease of manufacture
If a unitary layer structure is used for the check valve, then fabrication complexity is reduced and ease of manufacture is improved, but device functionality must be maintained
Solution Approach 1:
The single unitary layer of photoresist is designed to contain all necessary functional elements: the check valve leaf for flow direction control, the pivot axis for mechanical operation, and the bubble generation chamber for fluid ejection. This integration maintains full device functionality while simplifying fabrication to a single photolithography step.
Solution Approach 2:
The check valve leaf is designed with a pivot axis that allows it to dynamically change position between open and closed states. The living hinge structure enables the leaf to flex and pivot smoothly, maintaining reliable unidirectional flow control while being formed from the same continuous photoresist layer.
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 device effectively seals and directs fluid flow, preventing backflow and enabling controlled ejection and refilling, enhancing the functionality of microfluidic systems by using a polymer-based structure and resistive heating for fluid manipulation.
Implementation Method 1
a resistive device to create a bubble for fluid ejection and control
Data Source
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AI summary
An example fluidic micro electromechanical system may include a substrate and a first layer supported by the substrate. The first layer forms sides of a chamber, a passage through one of the sides and a chamber and a check valve leaf. The check valve leaf is pivotable about an axis nonparallel to the substrate to open and close the passage. The system may further include a second layer over the chamber, an opening into the chamber and a resistor supported within the chamber.