Optical Filter Film Thermal Drawing for Scalable Spectral Tuning

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Solution Overview

Problem

Existing methods for producing variable optical filters are expensive, lack scalability, and are sub-optimal for lightweight or compact optical systems due to their reliance on thick glass substrates and complex vacuum deposition processes.

Innovation Solution

A method of thermally drawing a multilayer polymeric preform using varying environmental conditions such as heat, pressure, tension, and drawing speed to create optical filters with varying optical properties, allowing for the production of flexible, thin-film filters with spatially or temporally varying spectral characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional vacuum deposition process is used to make variable optical filters, then optical filter performance is achieved, but production cost increases significantly and scalability is limited

Engineering Contradiction:
Improveoptical filter performanceVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the filter layer from the traditional vacuum deposition process and forms it separately through solution processing, then transfers it to the substrate. This separates the complex vacuum deposition step from the filter formation, allowing simpler, more scalable manufacturing while maintaining optical performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical vacuum deposition system with a solution-based chemical process. The filter is formed by depositing material from solution and then transferred, substituting complex mechanical vacuum equipment with simpler solution processing and transfer mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If traditional vacuum deposition process is used to make variable optical filters, then optical filter performance is achieved, but device complexity increases due to sophisticated motion or lithographical steps

Engineering Contradiction:
Improveoptical filter performanceVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the filter layer formation from the complex vacuum deposition process and performs it separately through solution processing. This removes the need for sophisticated motion control or lithographical steps during deposition, significantly simplifying the overall device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If thick glass substrates are used for traditional variable filters, then structural stability is maintained, but weight increases and compactness is reduced

Engineering Contradiction:
Improvestructural stabilityVSAvoidfilter weight
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The patent uses thin-film filters formed through solution processing and transfer, replacing thick glass substrates. The thin-film structure maintains sufficient structural stability for optical applications while dramatically reducing weight and enabling compact, flexible designs.

Inventive Principle:
Principle #30Flexible shells and thin films

4Stability of the object's composition

If thick glass substrates are used for traditional variable filters, then structural stability is maintained, but compactness is reduced

Engineering Contradiction:
Improvestructural stabilityVSAvoidfilter volume
Core Design Contradiction:
Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The patent employs thin-film structures formed by solution processing and transfer, replacing bulky thick glass substrates. This maintains the necessary structural stability for optical function while achieving compact, space-efficient designs suitable for modern optical systems.

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

This approach reduces production costs and enhances scalability, enabling the creation of lightweight, flexible filters with tunable optical properties suitable for a range of applications, including multi-spectral and hyperspectral imaging.

Implementation Method 1

the preform is drawn through a furnace subjecting the preform to a heating power that varies across a width of the furnace or over time or both across the width and over time

Methodology Applied
Scientific EffectThermal softening: Heating

Data Source

PatentEP3635452B1A method of making an optical filter film
Publication Date: 2025.11.05 EVERIX INC
  • EP3635452B1 patent drawingFigure 1~2B
  • EP3635452B1 patent drawingFigure 3A~4C
  • EP3635452B1 patent drawingFigure 5A~6B

AI summary

A method of making an optical filter film with varying optical properties includes the step of drawing a multilayer polymeric preform into an optical filter and varying at least one environmental condition being a member of the group including of heat, pressure, tension, and a drawing speed, the at least one environmental condition being varied over time or over a distance, or both, and causing a variation in layer thickness within the optical filter. The preform may be drawn through a furnace subjecting the preform to a heating power that varies across a width of the furnace or over time or both across the width and over time. The preform may also be drawn through the furnace while the drawing speed varies across a width of the furnace or over time or both across the width and over time.