Multifunctional Polarizing Filter Integral Structure Vignetting

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Solution Overview

Problem

Existing polarizing filters for digital cameras, when combined with ultraviolet cut and near-infrared cut filters, result in increased thickness leading to vignetting phenomena that adversely affect image quality, particularly in medical and testing applications where clear images are critical.

Innovation Solution

A multifunctional polarizing filter with an integral structure and minimal thickness is achieved by using a glass substrate with a dielectric multilayer film and an antireflection coating, bonded with adhesives, allowing for efficient ultraviolet and near-infrared ray blocking without the need for multiple filters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple filters (polarizing filter, ultraviolet cut filter, near-infrared cut filter) are attached separately to the front side of the lens, then each filter can perform its specific function, but the total thickness of the filters considerably increases causing vignetting phenomenon

Engineering Contradiction:
Improvefilter functionalityVSAvoidtotal thickness of filters
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent merges multiple separate filters (polarizing filter, ultraviolet cut filter, and near-infrared cut filter) into a single integrated multifunctional filter. The filter includes a polarizing film layer, an ultraviolet cut filter layer, and a near-infrared cut filter layer all combined in one structure that attaches to the lens front side, thereby reducing total thickness while maintaining all filter functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal filter that performs multiple functions simultaneously: polarization control, ultraviolet ray blocking, and near-infrared ray blocking. This multifunctional filter replaces the need for multiple separate filters, achieving space efficiency while providing comprehensive optical control for digital camera applications.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Length of stationary object

If a multifunctional polarizing filter with integral structure is created, then vignetting is prevented and image clarity is improved, but production challenges arise due to heat sensitivity and manufacturing complexity

Engineering Contradiction:
Improvefilter thicknessVSAvoidmanufacturing process
Core Design Contradiction:
Length of stationary objectVSEase of manufacture

Solution Approach 1:

The patent segments the manufacturing process into distinct sequential steps: first forming the polarizing film on a substrate, then separately forming the ultraviolet cut filter layer, and finally forming the near-infrared cut filter layer. This segmented approach allows each layer to be manufactured and optimized independently before integration, simplifying the overall production process despite the multifunctional nature of the final product.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs parameter changes in the manufacturing process, specifically controlling temperature parameters during the formation of each filter layer. By adjusting thermal parameters and using appropriate adhesives with suitable temperature ranges, the patent overcomes heat sensitivity issues during manufacturing while maintaining the integral structure of the multifunctional filter.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If separate filters are used, then manufacturing is simpler for each individual filter, but the combined thickness causes the captured image to be adversely affected by the frame of the filter

Engineering Contradiction:
Improveindividual filter productionVSAvoidvignetting phenomenon
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent combines multiple individual filters into one integrated unit, maintaining the manufacturing simplicity of producing each filter layer separately through sequential processing, while eliminating the cumulative thickness problem. The merged structure ensures that the overall filter assembly does not protrude enough to cause vignetting or frame interference in captured images.

Inventive Principle:
Principle #5Merging (Combining)

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 prevents vignetting, ensuring clear and accurate images by maintaining a thin profile while effectively blocking ultraviolet and near-infrared rays, overcoming production challenges related to heat sensitivity and mass production limitations.

Implementation Method 1

an ultraviolet cut thin film formed of a dielectric multilayer film being stacked on a surface of the ultraviolet cut glass substrate positioned on the camera side

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 2

coated with an antireflection coating

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 3

the main body being bonded by only a first and second adhesive

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2590013B1Polarising filter with multifunction and method for manufacturing polarising filter with multifunction
Publication Date: 2015.06.24 MARUMI OPTICAL
  • EP2590013B1 patent drawingFigure 1~2
  • EP2590013B1 patent drawingFigure 3~4
  • EP2590013B1 patent drawingFigure 5~6

AI summary

A multifunctional polarizing filter is used for a digital camera, and is produced by advanced optical technology to have a very small thickness and an integral structure in order to prevent a vignetting phenomenon in which the captured image is adversely affected by the frame of the filter.