Non-Uniform Switchable Shutter Filter for Selective Darkening
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Solution Overview
Problem
Existing darkening filters with uniform arrays of shutters can limit visibility due to inflexible switching, leading to unnecessary darkening and impaired viewing conditions while providing light protection.
Innovation Solution
A non-uniform pattern of switchable shutters with varying sizes, shapes, and spacings, along with a shutter control system that uses light intensity mapping and eye position monitoring to selectively switch shutters between light, dark, and intermediate states, allowing for flexible protection without compromising visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a uniform array of switchable shutters is used in a darkening filter, then sufficient protection from high-intensity light is provided, but visibility is limited due to inflexible switching and unnecessary darkening of large areas
Solution Approach 1:
The filter is divided into multiple independently controllable shutters arranged in a non-uniform pattern, allowing selective activation of only those shutters needed for light protection rather than darkening the entire filter area. This segmentation enables localized protection while preserving visibility in unaffected regions.
Solution Approach 2:
Different regions of the filter are assigned different shutter densities and sizes based on local protection requirements. The non-uniform pattern provides higher shutter density in areas requiring protection while maintaining lower density in areas where visibility is prioritized, creating locally optimized light control.
2Ease of manufacture
If a regular array of equidistantly arranged shutters is used, then manufacturing is simplified, but switching flexibility is reduced leading to larger darkened areas
Solution Approach 1:
The shutter array employs asymmetric spacing and varying shutter sizes rather than uniform equidistant arrangement. This asymmetric configuration allows the control system to selectively activate smaller subsets of shutters for protection, providing greater adaptability in controlling the darkened area while still maintaining manufacturability through systematic positioning.
3Device complexity
If uniform-sized shutters are used throughout the filter, then device complexity is reduced, but the ability to minimize impact on visibility is compromised
Solution Approach 1:
The filter incorporates shutters of varying sizes and densities in different regions, with larger shutters or higher density in areas requiring protection and smaller or sparser shutters in areas prioritizing visibility. This local differentiation optimizes viewing conditions while maintaining protection where needed.
Solution Approach 2:
The shutter pattern varies in multiple dimensions including size, spacing, and density across the filter surface. This multi-dimensional variation allows fine-tuned control over light blocking in different regions, enabling the system to protect against glare while preserving visibility in critical viewing areas.
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 non-uniform pattern and control system provide effective protection from high-intensity light while minimizing impact on viewing conditions, enabling smoother transitions and reduced switching time, thus enhancing user visibility and protection.
Implementation Method 1
The photodetector recognizes the presence of the incident light-to-be-filtered, and an electronic module generates a control voltage that, when applied to the switchable filter, causes the filter to change from the light-transmission-state to the dark-transmission-state
Implementation Method 2
The liquid-crystal molecules orientate themselves in a particular direction when a voltage is applied across the liquid-crystal cell under the control of an electronic module
Implementation Method 3
Automatic darkening filters have been designed which contain liquid-crystal cells located between polarizing films
Implementation Method 4
U.S. Pat. No. 4,240,709 to Hornell describes a switchable filter that has a single-twisted, nematic, liquid-crystal cell sandwiched between a pair of mutually crossed polarizers
Data Source
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AI summary
The present disclosure relates to darkening filters 10, 10' which are suitable for selectively darkening an optically transmissive window 20 for protection from light, in particular from high intensity light. The darkening filter 10, 10' is mounted in a forward-facing optically transmissive window 20 and comprises a non-uniform pattern 30 of switchable shutters 32 capable of being switching to at least a dark state and a light state by a shutter control system 40. The present disclosure also relates to a method of operating such darkening filters 10, 10'. The present disclosure furthermore relates to vision-protective headgears 100, 100', welding shields 110 and panes 120 comprising the darkening filters 10, 10' according to the present disclosure.