Fluid Lens Membrane Thermal Expansion Mitigation

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Solution Overview

Problem

Fluid lens element based optical systems face challenges in maintaining stable optical characteristics due to thermal expansion, as materials expand with temperature changes, leading to unwanted surface perturbations that deviate image-forming light rays from their intended path.

Innovation Solution

A fluid lens element with a deformable membrane featuring a formation, such as an accordion structure or sinusoidal pattern, that allows the membrane to expand preferentially at the formation, minimizing curvature changes and surface perturbations caused by thermal expansion, thereby maintaining optical stability across a range of temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fluid lens element is used to vary optical characteristics, then the optical system can adapt to different conditions, but thermal expansion of the membrane causes surface perturbations that degrade optical stability

Engineering Contradiction:

Improveoptical characteristic variabilityVSAvoidoptical stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The membrane is designed with non-uniform thickness, being thinner at the periphery and thicker at the center. This local variation in thickness allows the peripheral regions to expand more readily with thermal changes while the central region maintains structural stability, thereby accommodating thermal expansion without creating surface perturbations that would degrade optical quality

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention explicitly accounts for thermal expansion by designing the membrane thickness profile to match the expected thermal expansion characteristics. The thinner peripheral regions are designed to expand with temperature changes while maintaining optical surface integrity, converting the potentially harmful thermal expansion effect into a controlled design feature

Inventive Principle:

Principle #37Thermal expansion

2Reliability

If the membrane is made thinner to reduce thermal expansion effects, then thermal stability improves, but the membrane strength and ability to maintain optical quality deteriorates

Engineering Contradiction:

Improvethermal stabilityVSAvoidmembrane strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The membrane thickness is optimized locally: thinner at the periphery where thermal expansion occurs and thicker at the center where structural strength and optical quality are critical. This local differentiation allows the membrane to simultaneously achieve thermal stability through peripheral thinning while maintaining sufficient strength through central thickening

Inventive Principle:

Principle #3Local quality

3Reliability

If a formation is added to the membrane to accommodate thermal expansion, then optical stability improves, but the device complexity increases

Engineering Contradiction:

Improveoptical stabilityVSAvoidmembrane structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The formation is integrated directly into the membrane structure as a molded feature rather than adding separate components. The membrane itself is formed with the thickness variation pattern during manufacturing, creating an integrated flexible structure that accommodates thermal expansion without requiring additional parts or complex assembly

Inventive Principle:

Principle #30Flexible shells and thin films

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 surface perturbations and maintains optical stability, ensuring that image-forming light rays follow their intended path even with temperature changes, enhancing the performance of fluid lens elements in various environmental conditions.

Implementation Method 1

Most materials tend to expand at higher temperature and optical materials for use in fluid lens elements are no exception... accommodate changes in characteristics of the lens element attributable to changes in temperature so that an amount of perturbations in the lens element which would otherwise be exhibited with thermal expansion of the membrane are minimized

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS8305691B2Fluid lens element for use in changing thermal operating environment

Publication Date: 2012.11.06 HAND HELD PRODS INC

AI summary

There is provided a lens element configured so that optical characteristics thereof remain substantially stable over a range of operating temperatures. In one embodiment, a fluid lens element can be provided that includes a membrane having a formation formed thereon for accommodating changes in characteristics of the lens element attributable to changes in temperature so that an amount of perturbations in the lens element which would otherwise be exhibited with thermal expansion of the membrane are minimized.