Fluidic Lens Piezoelectric Actuation Sagging Correction

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Solution Overview

Problem

Variable-focus fluidic lenses face challenges with sagging due to gravity when aperture size increases and are unable to focus parallel rays of different wavelengths to the same point, limiting their achromatic capabilities.

Innovation Solution

A fluidic lens design featuring optically transparent walls with integrated deformable piezoelectric elements and a pressure-maintained cavity, allowing for voltage-induced shape changes and the use of multiple lenses with different refractive index fluids to achieve variable focus and achromatic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the aperture size is increased to improve light gathering capability, then the light gathering ability is improved, but the lens sags due to gravity

Engineering Contradiction:

Improveaperture areaVSAvoidlens shape stability

Core Design Contradiction:

Area of moving objectVSStability of the object's composition

Solution Approach 1:

The patent replaces the purely mechanical support structure with a piezoelectric actuation system. The piezoelectric element converts electrical signals into mechanical deformation, allowing precise control of the lens shape without relying solely on mechanical support structures that would allow sagging. This substitution enables active compensation for gravitational effects while maintaining structural integrity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces dynamic control capability through the piezoelectric element, allowing the lens shape to be actively adjusted in real-time. The lens transitions from a static, passively supported structure to a dynamically controllable system where the shape can be modified by applying voltage to the piezoelectric element, enabling compensation for sagging and other optical aberrations.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If a simple lens structure is used to reduce complexity, then the manufacturing simplicity is improved, but the lens cannot be achromatic

Engineering Contradiction:

Improvelens structure complexityVSAvoidachromatic focusing capability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent employs composite material structures by combining the piezoelectric element with the lens fluid and container walls. This composite approach allows the integration of multiple functions (actuation, optical focusing, and achromatic correction) within a unified structure, achieving achromatic capability without proportionally increasing overall system complexity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes in the piezoelectric element's physical state (through voltage application) to achieve different optical configurations. By changing the electrical parameter (voltage), the system can adjust the lens shape and focal properties to achieve achromatic focusing, avoiding the need for complex mechanical adjustment mechanisms.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the lens is designed for variable focus to improve adaptability, then the focus adjustment capability is improved, but the sagging problem worsens

Engineering Contradiction:

Improvevariable focus capabilityVSAvoidlens shape stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent replaces passive mechanical support with active piezoelectric actuation, allowing the lens to maintain its shape while achieving variable focus. The piezoelectric element provides precise, controllable deformation that enables focus adjustment without the structural compromises that lead to sagging in purely mechanical designs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent achieves variable focus through dynamic electrical control of the piezoelectric element rather than passive mechanical adjustment. This allows the lens to transition between different focal states while maintaining structural stability, as the piezoelectric actuation can be precisely controlled to achieve the desired optical configuration without compromising shape integrity.

Inventive Principle:

Principle #15Dynamics

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 design prevents sagging and enables achromatic focusing across different wavelengths, allowing for more complex lens configurations and improved optical performance, including correction of static aberrations and use in adaptive optics.

Implementation Method 1

at least one said wall comprising at least one optically transparent piezoelectric element which is deformable so as to change the shape of the cavity

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a cavity containing an optically transparent liquid and bounded by optically transparent walls arranged such that light may pass into the fluid via one said wall and exit from the fluid via another said wall

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS8717681B2Fluidic lens

Publication Date: 2014.05.06 BAE SYSTEMS PLC

AI summary

A fluidic lens includes a cavity 16 containing an optically transparent liquid and bounded by optically transparent walls 10, 32 arranged such that light may pass into the fluid via one wall and exit from the fluid via another wall, at least one said wall including at least one optically transparent piezoelectric element which is deformable so as to change the shape of the cavity.