Oleophobic Coating for Electrowetting Lens Fluid Stability
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Solution Overview
Problem
Implantable devices with electrowetting lenses containing immiscible fluids face challenges during implantation due to fluid dispersion and unwanted wetting of internal surfaces, leading to reduced efficacy and operational lifetime.
Innovation Solution
The use of a flexible polymeric material with an underwater oleophobic layer and immiscible fluids, where the oleophobic layer prevents the second fluid from wetting internal surfaces, and surfactants are added to control interfacial tensions and prevent fluid dispersion, allowing for controlled manipulation and deployment of the lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the adjustable lens is made flexible to enable folding or rolling for implantation, then the ease of implantation is improved, but the reliability of fluid containment deteriorates due to fluid dispersion and unwanted wetting
Solution Approach 1:
The lens housing is constructed from flexible polymeric material that can be folded or rolled to facilitate implantation through small incisions. The flexibility is achieved while maintaining structural integrity through careful material selection and design of the housing geometry.
Solution Approach 2:
An oleophobic coating is applied to the internal surfaces of the lens housing to act as an intermediary layer between the immiscible fluids and the polymer surface. This coating prevents unwanted wetting by the oil-based fluid while allowing the water-based fluid to maintain proper contact, thereby maintaining fluid containment stability during flexible manipulation.
2Adaptability or versatility
If immiscible fluids are used to provide adjustable optical power, then the optical functionality is improved, but the reliability deteriorates due to fluid mixing and wetting of improper surfaces
Solution Approach 1:
The patent uses immiscible fluid combinations where the oil-based fluid serves as a temporary, controllable element that can be easily manipulated in and out of contact with the optical path. The fluids are contained in a sealed system that prevents mixing, allowing reliable optical power adjustment without long-term degradation from fluid interaction.
Solution Approach 2:
The oleophobic coating on internal surfaces acts as a mediator that selectively interacts with the immiscible fluids. It prevents the oil-based fluid from wetting the polymer surface while allowing controlled contact through electrowetting actuation, maintaining fluid separation stability throughout operation.
3Duration of action of stationary object
If the lens materials are made durable and resistant to wetting, then the operational lifetime is extended, but the manufacturing complexity increases due to the need for specialized coatings
Solution Approach 1:
The lens housing employs a composite structure combining a flexible polymeric base material with an oleophobic coating layer. This composite approach provides both the flexibility needed for implantation and the wetting resistance required for long-term reliability, balancing manufacturing complexity with performance benefits.
Solution Approach 2:
The oleophobic coating is applied selectively to specific internal surfaces of the lens housing where fluid contact occurs, rather than coating the entire device. This localized application reduces manufacturing complexity while providing protection where it is most needed to extend operational lifetime.
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 solution enables the flexible deployment of the lens through smaller incisions, maintains optical clarity, and extends the operational lifetime by preventing fouling and dispersion of fluids, ensuring consistent optical power delivery.
Implementation Method 1
an underwater oleophobic layer having a contact angle with an oil, when submerged in water or another polar fluid, that is greater than 90 degrees
Implementation Method 2
surfactants are added to control interfacial tensions and prevent fluid dispersion
Implementation Method 3
the adjustable lens can contain two or more immiscible fluids (e.g., an oil and a saline fluid) and the relative locations and/or shapes of the fluids could be controlled to adjust the overall optical power of the immiscible fluids (e.g., by applying an electrical field)
Implementation Method 4
a second fluid that is disposed within the adjustable lens, that is immiscible with the first fluid, and that has a refractive index that differs from a refractive index of the first fluid
Data Source
Figure 1A~1C
Figure 1D
Figure 2A~2B
AI summary
An eye-implantable electrowetting lens can be operated to control an overall optical power of an eye in which the device is implanted. A lens chamber of the electrowetting lens contains first and second fluids that are immiscible with each other and have different refractive indexes. By applying a voltage to electrodes of the lens, the optical power of the lens can be controlled by affecting the geometry of the interface between the fluids. To prevent fouling the surface due to folding or other manipulation of the lens during the insertion process, one or more surfaces within the lens chamber is highly underwater oleophobic.