Liquid Lens Gravity Sag Correction via Pre-Distorted Membrane
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Solution Overview
Problem
Liquid lenses suffer from gravity sag distortion, leading to optical aberrations, particularly in large lenses oriented perpendicular to gravity, which existing methods attempt to mitigate by increasing membrane stiffness or using fluids with different refractive indices, but these solutions either increase energy requirements or lens thickness, reducing optical power and transition speed.
Innovation Solution
A liquid lens with a pre-distorted, rotationally asymmetric membrane that adopts a substantially rotationally symmetric shape when filled with fluid and oriented vertically, utilizing a flexible membrane with an electroactive layer that can change shape in response to an electric field, counteracting gravity-induced distortions and maintaining optical power within a predetermined range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If membrane stiffness is increased to reduce gravity sag distortion, then optical error is reduced, but energy requirements increase
Solution Approach 1:
The membrane is pre-distorted during manufacturing to have an asymmetric shape that anticipates and counteracts the symmetric distortion caused by gravity when filled. This preliminary action eliminates the need for continuous active correction, reducing energy requirements while maintaining optical precision.
Solution Approach 2:
The invention introduces asymmetric pre-distortion to the membrane shape to compensate for symmetric gravity-induced distortion. By making the membrane inherently asymmetric in its resting state, the system achieves optical correction without requiring additional energy input.
2Manufacturing precision
If fluids with different refractive indices are used to mitigate gravity sag, then optical power is maintained, but lens thickness increases
Solution Approach 1:
The membrane is pre-shaped during manufacturing to counteract gravity distortion before the lens is assembled and used. This preliminary geometric correction eliminates the need for additional optical elements or fluid layers, maintaining optical power without increasing lens thickness.
3Manufacturing precision
If membrane stiffness is increased to reduce gravity sag, then optical error is reduced, but transition speed decreases
Solution Approach 1:
The membrane is pre-distorted during manufacturing to have an asymmetric shape that automatically compensates for gravity-induced symmetric distortion. This passive geometric correction maintains optical precision without requiring a stiffer membrane, thereby preserving fast transition speeds.
4Manufacturing precision
If pre-distortion is applied to counteract gravity sag, then optical power uniformity is improved, but device complexity increases
Solution Approach 1:
The pre-distortion is applied during the membrane manufacturing process itself, integrating the correction function into the base component rather than adding separate active correction systems. This approach improves optical uniformity while minimizing increases in overall device complexity.
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 reduces gravity sag distortion, maintaining low optical error across a broad range of optical powers and allowing for compact, efficient design, with improved optical power uniformity and reduced aberrations, even at non-zero tilt angles.
Implementation Method 1
a flexible membrane with an electroactive layer that can change shape in response to an electric field
Implementation Method 2
when the cavity is filled with the fluid and the substrate is disposed vertically w.r.t. gravity at a pre-defined clocking angle, the membrane adopts a substantially rotationally symmetric shape
Data Source
AI summary
A liquid lens includes a substrate, a transparent elastic membrane forming a cavity with the substrate, and a transparent fluid filling the cavity between the substrate and the membrane. The membrane has a pre-distorted, rotationally asymmetric shape in absence of the fluid in the cavity. When the cavity is filled with the fluid and the substrate is disposed vertically w.r.t. gravity at a pre-defined clocking angle, the membrane adopts a substantially rotationally symmetric shape due to elasticity of the membrane counteracting gravity exerting a downward force on the fluid in the cavity, reducing the effect of the gravity sag on optical performance of the liquid lens.