Curved Automatic-Darkening Filter With Flexible Glass
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Solution Overview
Problem
Existing automatic darkening filters, typically made with flat glass substrates, are heavy and limit the user's field of view due to their rectangular configuration, which can cause discomfort and restrict peripheral vision.
Innovation Solution
A switchable filter using flexible, curved glass substrates with liquid-crystal cells between polarizers, allowing for a lighter and more versatile design that can be shaped to accommodate the user's face, providing an expanded viewing area and improved ergonomics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If flat glass substrates are used in automatic darkening filters, then the filter structure is simple and easy to manufacture, but the weight increases and causes stress and tension in the user's neck and shoulders
Solution Approach 1:
The patent applies curvature to the glass substrates, transforming them from flat to curved surfaces. This curvature enables the filter to conform to the contours of the user's face while reducing the overall weight of the assembly. The curved geometry allows for a more ergonomic design that distributes weight more effectively and provides a larger field of view without increasing mass.
2Ease of manufacture
If rectangular configuration is used in automatic darkening filters, then the manufacturing process is simplified, but the user's field of view is limited and peripheral vision is restricted
Solution Approach 1:
The rectangular configuration is replaced with a curved geometry that follows the natural contours of the face. This curved design expands the field of view by allowing light to pass through the filter at various angles while maintaining structural integrity. The curved shape eliminates the hard edges of rectangular designs, providing a more natural viewing experience with enhanced peripheral vision.
3Weight of moving object
If flexible curved glass substrates are used, then weight is reduced and field of view is enhanced, but the manufacturing complexity increases due to difficulties in scribing and breaking rigid glass substrates
Solution Approach 1:
The patent employs flexible glass substrates that can be bent and shaped without breaking. These thin, flexible glass layers allow the filter to be formed into curved configurations that conform to facial contours. The flexibility of the glass substrates enables complex shaping processes that would be impossible with rigid glass, thereby reducing weight and enhancing field of view while managing manufacturing complexity through advanced material properties.
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 flexible, curved design reduces overall weight and enhances the user's field of view, allowing for a larger viewing area with less weight, and can be configured to fit various shapes, including goggles or helmets, improving comfort and usability.
Implementation Method 1
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 2
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 3
U.S. Patent 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
Figure 1~2
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AI summary
A switchable filter (10, 10') that comprises: a first polarizer (14) having a first polarization direction; a second polarizer (18) having a second polarization direction, which may be the same or different from the first polarization direction; and a first liquid-crystal cell (16) disposed between the first and second polarizers, the liquid crystal cell containing first and second optically-transparent flexible glass layers (40, 42) that are curved and that have a first liquid crystal layer (48) located between them. The switchable filter may be included in an automatic darkening filter (60), said automatic darkening filter further comprising a control circuitry (66) and a sensor (64) that detects incident light and that causes a signal to be sent to the switchable filter via the control circuitry, which signal causes molecular rotation within the liquid crystal layer.