Elastomer Flexures for Fluid Lens Actuation Force Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Adjustable fluid lenses face challenges in reducing the required actuation force for membrane distortion, particularly due to high membrane strain during actuation, which can be exacerbated by the use of simple fixed perimeter eye wire deflectors, leading to inefficiencies in devices like augmented and virtual reality systems.
Innovation Solution
The implementation of a zero-strain actuation profile in fluid lenses using flexures with elastic elements that mechanically couple the membrane to a substrate, allowing control points to follow a predetermined trajectory without significant change in elastic strain energy, thereby reducing the actuation force required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple fixed perimeter eye wire deflectors are used to actuate the membrane, then the device structure is simple, but the membrane strain during actuation becomes high requiring large actuation force
Solution Approach 1:
The patent changes the actuation parameters by guiding control points along specific trajectories that maintain approximately constant elastic strain energy in the membrane. This trajectory-based actuation approach transforms the actuation process from high-strain direct distortion to controlled movement along energy-conserving paths, thereby reducing the required actuation force while maintaining membrane functionality
Solution Approach 2:
The patent introduces flexures as intermediary mechanical elements between the actuator and the membrane. These flexures couple the membrane to the substrate and guide the membrane's control points along predetermined trajectories, acting as a mediator that transforms simple actuator motion into controlled membrane deformation with reduced strain and lower required actuation force
2Ease of operation
If high membrane strain is applied during actuation to achieve membrane distortion, then the membrane can be actuated, but the elastic strain energy increases leading to inefficiency
Solution Approach 1:
The patent transforms the actuation parameters by defining specific trajectories for membrane control points that maintain approximately constant elastic strain energy. This approach changes the actuation mode from high-energy strain-based deformation to low-energy trajectory-following motion, thereby reducing energy consumption while achieving the same membrane distortion effect
Solution Approach 2:
The flexure mechanism is designed to guide the membrane control points along predetermined trajectories automatically, utilizing the mechanical coupling between the flexure and membrane to enforce the energy-conserving path without requiring active control or additional energy input, allowing the system to self-regulate energy usage
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 approach enables low resistance force, long life, and compact device configurations by maintaining approximately constant elastic energy during actuation, improving the efficiency and performance of adjustable fluid lenses in various applications.
Implementation Method 1
The flexure includes an elastomer-based elastic element. The elastomer may include a natural rubber, a synthetic rubber (e.g., a nitrile rubber), or a blend of two or more elastomers.
Data Source
AI summary
In some examples, a device includes a fluid lens having a substrate and a membrane connected to the substrate using a flexure. The fluid lens may include a fluid located within a cavity at least partially defined by the substrate and the membrane. The flexure may include a membrane attachment and an elastic element. The device may be configured so that a displacement of the membrane attachment adjusts a profile of the membrane, and may induce a compression of at least a portion of the elastic member. In some examples, a flexure may include a plurality of elastic elements, which may be attached to the substrate (e.g., through a flexure support), and a rigid element, that may include or be connected to the membrane attachment. Example devices include head-mounted devices, such as augmented reality or virtual reality devices.