Filling Micrometer Cavities with Dual-Weight Polymer Solution
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Solution Overview
Problem
Filling micrometric-sized cavities with a solution containing a solvent and polymer is challenging due to capillarity issues and solvent evaporation problems, which lead to incomplete filling and structural deformation, hindering the formation of a well-structured composite material for light conversion applications.
Innovation Solution
A solution comprising a first solvent, a first polymer of low molecular weight, a second polymer of high molecular weight, luminophores, and a surfactant, where the second molecular weight is 10 to 50 times greater than the first, allowing for homogeneous filling and preventing capillary phenomena, ensuring a stable solid structure after solvent evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a solution containing solvent and polymer is deposited in micrometric cavities, then the cavities can be filled with conversion material, but capillary forces cause the liquid to rise along the cavity walls and deform the air/solid interface, leading to incomplete filling and poor structural organization
Solution Approach 1:
The patent changes the physical-chemical parameters of the solution by incorporating surfactants that modify surface tension and interfacial properties. This parameter change allows the liquid to resist capillary rise along the walls and maintains a horizontal air/solid interface during evaporation, thereby achieving complete and organized filling of micrometric cavities
Solution Approach 2:
The patent introduces surfactants as intermediary substances between the liquid solution and the cavity walls. These surfactants mediate the interaction by reducing surface tension and preventing excessive capillary adhesion, allowing the liquid to fill the cavity uniformly without rising along the walls or deforming the interface
2Stability of the object's composition
If the solvent evaporates during filling, then the solid composite material forms, but the evaporation deforms the air/solid interface and creates porosity, preventing well-structured material formation
Solution Approach 1:
The patent modifies the evaporation parameters by using surfactants that stabilize the air/solid interface during the evaporation process. This prevents interface deformation and maintains structural organization throughout the drying phase, eliminating porosity and ensuring uniform solid composite material formation
Solution Approach 2:
The patent applies surfactants beforehand to the solution to create a protective effect during evaporation. This pre-treatment cushions against interface deformation by maintaining surface stability, preventing the formation of pores and ensuring the solid material maintains its organized structure as the solvent evaporates
3Manufacturing precision
If the cavity size is reduced to micrometric dimensions, then the resolution and luminous flux are improved, but capillary forces and surface forces dominate over gravitational and inertial forces, making filling difficult
Solution Approach 1:
The patent changes the surface tension parameters of the filling solution by adding surfactants, which enables the liquid to overcome dominant capillary forces at micrometric scales. This parameter modification allows complete cavity filling despite the small dimensions where surface forces prevail over gravitational forces
Solution Approach 2:
The patent introduces surfactants as intermediary agents that facilitate filling at micrometric scales. These intermediaries modify the liquid's interaction with the cavity walls, reducing capillary adhesion and enabling uniform filling in dimensions where traditional filling methods fail due to dominant surface forces
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 solution effectively fills micrometric cavities with a composite material that maintains a horizontal air/solid interface, preventing deformation and ensuring homogeneous phosphor dispersion, thus achieving efficient light conversion and maintaining structural integrity.
Implementation Method 1
Capillarity is an interaction phenomenon that can occur at the interfaces between a liquid and a surface. Capillarity is due to surface tension forces between the different phases present. Because of capillary forces on the cavity walls, the free surface of a liquid is not horizontal.
Implementation Method 2
Capillarity is due to surface tension forces between the different phases present. The surface tension force F and the liquid height h are defined, respectively, by the following equations in the case where the cavity is a tube
Implementation Method 3
This effect is due to the fact that the curvature of the interface is greatly reduced at the angle and that the Laplace pressure is low there, causing the liquid to move forward along the angle.
Implementation Method 4
Wetting walls lead to a concave liquid surface, while non-wetting walls produce a convex surface. In the case of a non-wetting wall, there is a limit beyond which the liquid completely separates from the angle.
Implementation Method 5
As the solvent evaporates, it deforms the air/solid interface, potentially creating porosity in the material. This phenomenon depends primarily on the solvent vapor pressure near the cavities, which determines the solvent evaporation rate
Data Source
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AI summary
Solution for use in filling micrometer-size cavities (10), the solution comprising a first solvent, a first polymer (102) having a first molecular weight, a second polymer (103) having a second molecular weight, phosphors (101) and a surfactant, the second molecular weight being 10 to 50 times greater than the first molecular weight.