Flexible Electrowetting Lens for Curved Surfaces
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Solution Overview
Problem
Existing microlenses are either limited to tunable variable-focus on flat surfaces or require complex mechanical systems for curved surfaces, lacking flexibility and efficient response time.
Innovation Solution
A variable-focus lens system with an electrowetting liquid lens on a flexible substrate that can be wrapped onto curved surfaces, using immiscible liquids and low-temperature fabrication processes to achieve a compact, responsive, and flexible design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrowetting microlenses are fabricated on rigid flat substrates, then the lens structure is stable and easy to manufacture, but the lens cannot be integrated onto curved surfaces
Solution Approach 1:
The patent employs a flexible substrate (such as a flexible circuit board or thin polymer film) to replace the traditional rigid flat substrate. This flexible substrate can be conformally mounted onto curved surfaces while maintaining the electrowetting lens functionality. The flexible substrate acts as a carrier that adapts to the curved geometry without compromising the lens structure or requiring complex fabrication processes.
2Adaptability or versatility
If thermo-sensitive hydrogels are used for actuation on curved surfaces, then the lens can be tuned on curved surfaces, but the response time becomes long due to temperature dependant actuation
Solution Approach 1:
The patent replaces the thermal actuation mechanism (thermo-sensitive hydrogels) with an electrical actuation mechanism (electrowetting). The electrowetting lens uses voltage-controlled changes in interfacial tension between immiscible liquids to achieve rapid focal length tuning. This electrical actuation method eliminates the slow thermal diffusion process, providing response times in the millisecond range while maintaining compatibility with curved surface integration.
3Ease of operation
If phase modulation is used for variable-focus tuning, then the lens can be tuned, but the magnitude of change in focal length is limited due to material properties
Solution Approach 1:
The patent employs electrowetting to dynamically change the interfacial tension parameter between two immiscible liquids (typically a water-based liquid and an oil-based liquid). By applying voltage, the interfacial tension changes, which directly alters the curvature of the liquid-liquid interface and thus the focal length. This parameter change mechanism allows for a large tuning range of focal lengths, overcoming the limitations of phase modulation materials.
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
Enables flexible integration onto curved surfaces like camera lenses or contact lenses with improved field of view and three-dimensional effects, while reducing fabrication stress and enhancing response speed.
Implementation Method 1
The curved interface defines a radius of curvature responsive to an electrical stimulus to vary the radius of curvature for tuning a focal length of the electrowetting liquid lens
Data Source
AI summary
A variable-focus lens system that includes a lens assembly having an electrowetting liquid lens that can be wrapped onto a curved surface such as a lens without distorting a chamber holding the electrowetting liquid lens is provided. The lens assembly includes a container body having a cup, in which the chamber is defined, and supports that extend in different directions from the cup. A flexible base substrate is arranged under the container body. Both the container body and flexible base substrate may be made from a soft polymer material and made using low-temperature fabrication processes. The flexible base substrate may be thinner than the container body and provide a relatively large surface area that engages the curved surface such that the stresses associated with wrapping a micro lens assembly onto the curved surface may be primarily absorbed by the flexible base substrate.