Pre-strained Membrane Fluid Lens Reduces Actuation Force
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Solution Overview
Problem
Conventional fluid lenses require high actuation forces to adjust optical power, limiting their compactness and efficiency due to significant changes in membrane strain energy during adjustment.
Innovation Solution
The development of a 'zero-strain' fluid lens configuration, where the membrane profile adjustment does not appreciably change the elastic energy, using a pre-strained flexible membrane with a support structure that allows control points to move along guide paths without altering the strain energy, reducing actuation forces by an order of magnitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional fluid lenses use traditional membrane configurations for optical power adjustment, then the lens can change optical power, but high actuation forces are required due to significant changes in membrane strain energy
Solution Approach 1:
The patent applies parameter changes by modifying the membrane configuration from a conventional state to a pre-strained state. The membrane is subjected to controlled strain during fabrication to create a pre-strained configuration where the elastic energy is optimized. This pre-straining parameter change allows the membrane to undergo optical power adjustment with minimal additional strain energy, thereby reducing the actuation force required by an order of magnitude.
Solution Approach 2:
The patent implements preliminary action by pre-straining the membrane during the fabrication process before the lens is put into service. The membrane is stretched and secured in a pre-strained configuration during manufacturing, so that when optical power adjustment is needed during operation, the membrane already has the necessary elastic energy stored. This preliminary straining action eliminates the need for high actuation forces during normal operation.
2Productivity
If high actuation forces are used to adjust optical power, then the membrane can be reconfigured, but the lens becomes less compact and less efficient
Solution Approach 1:
The patent changes the membrane's physical state from unstrained to pre-strained during fabrication. This parameter change creates a configuration where the membrane stores elastic energy in advance, allowing optical power adjustment to occur with minimal additional force. The pre-strained state optimizes the membrane's mechanical properties to enable efficient, low-force actuation during operation.
Solution Approach 2:
The pre-strained membrane configuration allows the lens system to be self-sufficient during operation. The membrane's pre-stored elastic energy enables it to self-adjust to different optical power states without requiring continuous high-force actuation. The system uses the membrane's inherent elastic properties, optimized during fabrication, to provide efficient optical adjustment.
3Force
If the membrane is pre-strained to reduce actuation force, then the actuation force is reduced by an order of magnitude, but the membrane configuration becomes more complex
Solution Approach 1:
The patent applies preliminary action during the fabrication process, where the membrane is pre-strained and secured before the lens is assembled. This preliminary straining is performed as part of the standard manufacturing sequence, integrating the complex membrane configuration step into the existing fabrication workflow. By doing so during manufacturing rather than during operation, the complexity is managed in a controlled manufacturing environment rather than requiring complex operational procedures.
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 configuration significantly reduces the actuation force required, enabling the use of smaller, more efficient actuators, resulting in a more compact and efficient fluid lens design with stable optical properties.
Implementation Method 1
a pre-strained flexible membrane wherein the membrane is pre-strained such that adjustment of the membrane profile does not result in appreciable changes in elastic strain energy within the membrane
Data Source
AI summary
Examples include a device including a fluid lens having a membrane, a substrate, and a fluid at least partially enclosed between the membrane and the substrate. One or more support structures may be configured to provide a guide path for an edge portion of the membrane, which may be an elastic membrane in tension. In some examples, a membrane includes a membrane polymer, such as a thermoplastic urethane polymer, and a polymer additive, such as an acrylate polymer. The polymer additive may reduce or substantially eliminate diffusion of the fluid into the membrane, which may increase the stability and performance of the fluid lens.