Microfluidic Membrane Pump Using Rigid Diaphragm Bonding
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Solution Overview
Problem
Current microfluidic systems face challenges with high manufacturing costs and low yields due to the distortion or blocking of microfluidic pathways during bonding, requiring complex and expensive fabrication processes, and lack of seamlessly integrated active components like pumps and valves that are compatible with polymeric materials.
Innovation Solution
The development of microfluidic structures with a substantially rigid diaphragm that can be actuated between a relaxed and an actuated state, using a weak organic solvent for bonding between a rigid plastic membrane and substrate, allowing for easy fabrication and integration of components like valves and pumps, with features such as bonded and unbonded regions for fluid flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional bonding techniques (thermal, ultrasonic, solvent bonding) are used to assemble multilayer microfluidic structures, then the device can be manufactured, but the microfluidic pathways become distorted or blocked due to low dimensional rigidity of polymeric materials
Solution Approach 1:
The patent applies preliminary action by pre-forming recesses in the substrate before bonding the membrane. These recesses are created in advance to accommodate the membrane in a predetermined configuration, ensuring that the membrane maintains proper positioning and does not block microfluidic pathways during bonding. This preliminary structuring prevents distortion while enabling conventional bonding techniques.
Solution Approach 2:
The patent implements local quality by creating localized recesses only in specific areas where the membrane needs to be positioned. The substrate has different geometries in different regions: recessed areas for membrane accommodation and flat areas for bonding. This localized modification allows the membrane to be properly positioned without affecting the overall structural integrity of the microfluidic pathways.
2Adaptability or versatility
If each microfluidic device is independently designed for each application with specially designed components, then the device can be optimized for specific functions, but the manufacturing cost increases significantly
Solution Approach 1:
The patent applies universality by designing a standardized substrate-membrane assembly structure that can serve multiple functions across different applications. The recess-formed configuration provides a universal platform that can accommodate various membrane types and configurations while maintaining the same basic manufacturing process. This allows the same manufacturing approach to be used for different microfluidic applications, reducing per-device costs while maintaining application-specific optimization capabilities.
3Ease of operation
If exterior pumps and valves are used to induce fluid flow, then the system can achieve fluid control, but the system volume becomes much larger than the microfluidic system
Solution Approach 1:
The patent applies merging by integrating the pump or valve functionality directly into the microfluidic device structure itself. The membrane, when deformed, serves dual purposes: it seals the microfluidic pathways and simultaneously acts as the actuating element for fluid flow control. This eliminates the need for separate exterior pumps and valves, reducing system volume while maintaining fluid control capabilities.
Solution Approach 2:
The patent implements nesting by placing the membrane within the microfluidic device structure, specifically within recesses formed in the substrate. The membrane is nested within the device housing, and its deformation is contained within the device boundaries. This nested configuration allows the actuating mechanism to be compact and integrated, avoiding external components that would increase system volume.
4Manufacturing precision
If complex fabrication sequences are used to produce active microfluidic components, then the components can be produced with required precision, but very little window is left to integrate the rest of the microfluidic system
Solution Approach 1:
The patent applies extraction by removing the complex fabrication steps from the overall manufacturing process. Instead of using complex fabrication sequences to create the active components, the invention extracts the complexity by using simple recess formation in the substrate followed by straightforward membrane bonding. This simplifies the fabrication sequence while maintaining precision through the geometric constraints provided by the recesses.
Solution Approach 2:
The patent implements parameter changes by transitioning from complex multi-step fabrication processes to a simplified process based on geometric parameters. The recess depth, width, and shape are controlled as key parameters during molding or machining, and these parameter specifications ensure precise membrane positioning without requiring complex subsequent fabrication steps. This parameter-driven approach reduces device complexity while maintaining manufacturing precision.
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
This approach results in robust, easy-to-manufacture microfluidic systems with improved yield and reduced costs, enabling the integration of active components like pumps and valves within the microfluidic system without interfering with the intended process, thus enhancing the functionality and cost-effectiveness of microfluidic devices.
Implementation Method 1
bonded to the upper surface of the first substrate with a weak organic solvent
Implementation Method 2
pneumatic pressure or force is applied through the chamber to deform the membrane
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3C
AI summary
Plastic microfluidic structures having a substantially rigid diaphragm that actuates between a relaxed state wherein the diaphragm sits against the surface of a substrate and an actuated state wherein the diaphragm is moved away from the substrate. As will be seen from the following description, the microfluidic structures formed with this diaphragm provide easy to manufacture and robust systems, as well readily made components such as valves and pumps.