Variable-Stiffness Fluid Lens Support for Gravity Sag Control

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Solution Overview

Problem

Existing liquid lenses suffer from gravity-induced distortion due to pressure gradients, leading to undesirable lens surface tilting and visual aberrations, especially when not actuated, which affects the optical performance.

Innovation Solution

Incorporation of a dynamic actuator supported by a variable-stiffness spring member that minimizes aberrations caused by gravity sag in the unactuated state while enabling the formation of a spherical lens shape in the actuated state, using electroactive materials like piezoelectric polymers and ceramics to apply an electric field for actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a liquid lens is not actuated, then it should remain in a stable unactuated state, but gravity causes pressure gradients that lead to lens surface tilting and visual aberrations

Engineering Contradiction:

Improvelens surface stabilityVSAvoidgravity-induced distortion

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent employs a spring member that provides an upward elastic force to counterbalance the downward gravitational force acting on the liquid lens. This counterweight mechanism prevents gravity-induced pressure gradients and lens surface tilting, maintaining optical quality in the unactuated state without requiring active power consumption.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The spring member's elastic properties are specifically designed to provide appropriate support force that changes with compression, allowing the lens to maintain optimal optical parameters in both unactuated and actuated states. The spring constant and pre-compression are tuned to compensate for gravity while enabling full actuation range.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If spring support is added to counteract gravity, then gravity-induced distortion is reduced, but device complexity increases

Engineering Contradiction:

Improvegravity sagVSAvoidsupport structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The spring member is implemented as a thin, flexible elastic element that provides necessary mechanical support with minimal structural complexity. This flexible support mechanism efficiently counteracts gravity while maintaining a compact, simple device architecture compared to rigid support structures.

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If uniform spring support is used around the lens periphery, then manufacturing is simplified, but optical performance deteriorates due to inability to correct localized aberrations

Engineering Contradiction:

Improvespring support uniformityVSAvoidoptical quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The spring member is designed with spatially varying properties, including regions of different stiffness and positioning, to provide localized support that compensates for specific optical aberrations. This non-uniform spring configuration optimizes optical performance by addressing localized deformation needs while maintaining overall structural integrity.

Inventive Principle:

Principle #3Local quality

4Shape

If the lens is actuated to form a spherical shape, then optical power is achieved, but gravity causes cylinder formation and visual aberrations

Engineering Contradiction:

Improvelens curvatureVSAvoidcylinder formation

Core Design Contradiction:

ShapeVSObject-affected harmful factors

Solution Approach 1:

The spring member continuously counteracts gravitational force during actuation, preventing the formation of unwanted cylindrical distortions and maintaining pure spherical lens shapes. This ensures that optical power is achieved without introducing visual aberrations from gravity-induced deformations.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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-induced distortion, maintaining high optical quality by allowing the lens to form a desired shape, correcting visual aberrations and ensuring clear vision across different states.

Implementation Method 1

The optical element may include one or more layers of an electroactive material where each layer is individually electroded and independently oriented in-plane

Methodology Applied

Scientific EffectElectroactive material response to electric field: Electroactive Polymer

Implementation Method 2

using electroactive materials like piezoelectric polymers and ceramics to apply an electric field for actuation

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS20250321366A1Fluid lens having variable-stiffness support

Publication Date: 2025.10.16 META PLATFORMS TECHNOLOGIES LLC

AI summary

A variable-stiffness spring member may be integrated into a deformable optical element, such as a fluid lens. An example fluid lens may include a substrate, an actuator, a fluid layer disposed between the substrate and the actuator, and a spring member disposed between the substrate and the actuator. The spring member may include a flexure that at least partially surrounds the fluid layer and a spring stiffness of the flexure may differ at each of at least two peripheral locations around the fluid layer. Various other devices, systems, and methods are also disclosed.