Laser Joining Microfluidic Substrates Without Adhesives
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Solution Overview
Problem
Existing methods for joining materials in microfluidic devices often require additives or externally applied adhesives, which can be limiting in precision and reliability, especially when forming joints without external forces.
Innovation Solution
A method involving the use of laser irradiation to increase the absorbance of one substrate, followed by contact with another substrate and subsequent irradiation with a different wavelength laser to achieve localized melting and joining, potentially combined with ultrasonic energy to facilitate bonding without external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure sensitive adhesives are used for joining substrates, then the joining process is simple and fast, but the reliability and precision of the joint are insufficient
Solution Approach 1:
The patent replaces mechanical joining methods (pressure sensitive adhesives requiring external force) with laser-induced acoustic wave joining. The laser beam generates acoustic waves that propagate through the substrate and create joining at the interface without requiring external mechanical pressure, thus maintaining simplicity while improving reliability.
Solution Approach 2:
The patent changes the physical state of the substrate by using laser irradiation to generate acoustic waves. The laser parameters (wavelength, power, pulse duration) are controlled to generate acoustic waves of specific frequencies that resonate with the substrate structure, creating reliable joints without external adhesives or forces.
2Ease of manufacture
If externally applied adhesives are used, then joining can be achieved, but the precision and control of the joint formation are limited
Solution Approach 1:
The patent replaces chemical joining methods (adhesives) with a physical field-based method using laser and acoustic waves. This substitution enables precise control of the joining process through laser parameter adjustment, achieving both ease of manufacture and high manufacturing precision without external adhesives.
Solution Approach 2:
The substrate itself serves as the joining medium through its acoustic wave propagation characteristics. The laser-induced acoustic waves utilize the substrate's own mechanical properties to create the joint, eliminating the need for external adhesives and enabling precise control through laser parameter management.
3Manufacturing precision
If laser irradiation is used to increase absorbance, then localized melting and joining precision are improved, but the process complexity increases
Solution Approach 1:
The patent merges laser irradiation and acoustic wave generation into a single integrated process. The laser beam serves dual functions: heating the substrate to increase absorbance and generating acoustic waves for joining. This combination achieves high precision while managing complexity through process integration rather than separate steps.
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 allows for precise and reliable joining of substrates without the need for external adhesives or forces, enhancing the reproducibility and reliability of microfluidic device assembly by creating strong, leak-proof joints with controlled gap distances.
Implementation Method 1
irradiating a portion of a first substrate with a laser having a first wavelength and intensity sufficient to increase the absorbance of the first substrate to light having a second, different wavelength
Implementation Method 2
increase the absorbance of the first substrate to light having a second, different wavelength
Implementation Method 3
irradiating the contacted portions of the first and second substrates with light having the second wavelength and an intensity sufficient to join the first and second substrates
Implementation Method 4
the irradiated portion of the first substrate is irradiated with a second laser having a second wavelength, different from the first wavelength
Implementation Method 5
applying ultrasonic energy to facilitate bonding without external forces
Data Source
Figure 1~2
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AI summary
The present invention relates to methods for joining materials as well as articles manufactured using such processes. The invention pertains to a process for joining a first substrate to a second substrate. The process includes irradiating a portion of a first substrate with a laser beam having a first wavelength and intensity sufficient to increase the absorbance of the first substrate to light having a second, different wavelength. The laser beam may carbonize at least a portion of the irradiated portion of the first substrate imparting a higher absorbance to light than non-irradiated portions of the first substrate. A second substrate is then placed in contact with the irradiated portion of the first substrate. The first substrate is then irradiated with a second laser having a second wavelength, different to the first wavelength; with a sufficient intensity to heat and, preferably melt, the irradiated portion of the first substrate.