Wavelength-Specific Limiter Stack for Angle-Independent Laser Protection
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Solution Overview
Problem
Conventional wavelength-specific filters for protecting eyes and sensors from damaging lasers are limited by their dependence on the angle of impingement, allowing only 30% of visible light to pass and resulting in poor image quality, and lack independence from impingement angles, making them unsuitable for wide-angle protection.
Innovation Solution
An impingement angle-independent wavelength-specific limiter is developed using a stack of wavelength-specific limiters activated by corresponding wavelengths, employing up-conversion materials to generate UV or short visible light that triggers photochromic dyes to absorb and limit high-intensity laser wavelengths, while maintaining transparency to lower intensity light and allowing full recovery after removal of high-intensity light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thin film interference filter is used to block specific wavelengths, then the filter can effectively block damaging laser wavelengths, but the filter becomes strongly dependent on the angle of impingement and allows only about 30% of visible light to pass, resulting in poor image quality
Solution Approach 1:
The filter is divided into multiple discrete wavelength-specific filter elements, each targeting a specific laser wavelength (e.g., 532nm green, 450nm blue, 650nm red). This segmentation allows each element to be optimized for its specific wavelength while maintaining overall broad-spectrum protection without the angle dependence issues of conventional broad-band filters.
Solution Approach 2:
Different regions of the filter contain different wavelength-specific filter elements with locally optimized properties. Each local region is designed to block a specific wavelength while being transparent to others, allowing the filter to maintain high overall transmission while providing targeted protection where needed.
2Reliability
If a thin film interference filter is used to block specific wavelengths, then the filter can provide wavelength-specific protection, but the filter is strongly dependent on the angle of impingement, limiting its applicability to perpendicular incidence only
Solution Approach 1:
The filter transitions from a conventional two-dimensional thin film structure to a three-dimensional assembly of multiple wavelength-specific filter elements arranged in a stack or array. This dimensional change allows the system to maintain wavelength-specific performance while becoming insensitive to the angle of incident light, as the multiple elements collectively cover the range of incident angles.
3Object-affected harmful factors
If a conventional filter is used to protect against multiple wavelengths (blue, green, red), then the filter can block these wavelengths at angles up to 30°, but only about 30% of visible light can pass through
Solution Approach 1:
The filter is divided into multiple discrete wavelength-specific filter elements, each targeting a specific laser wavelength (e.g., 532nm green, 450nm blue, 650nm red). This segmentation allows each element to be optimized for its specific wavelength while maintaining overall broad-spectrum protection without the angle dependence issues of conventional broad-band filters.
Solution Approach 2:
Different regions of the filter contain different wavelength-specific filter elements with locally optimized properties. Each local region is designed to block a specific wavelength while being transparent to others, allowing the filter to maintain high overall transmission while providing targeted protection where needed.
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 limits high-intensity laser wavelengths across multiple angles without compromising image quality, ensuring protection against damaging laser light while maintaining transparency to lower intensity light and allowing full recovery after high-intensity light removal.
Implementation Method 1
Up-conversion refers to nonlinear optical processes characterized by the successive absorption of two or more pump photons via intermediate long-lived energy states followed by the emission of the output radiation at a shorter wavelength than the pump wavelength
Implementation Method 2
The present disclosure relates to absorption of impingement angle-independent laser light in up-converting materials, and the use of the re-emitted light to tint a photochromic dye, which in turn can limit the transmission of the exciting laser
Data Source
AI summary
An impingement angle-independent wavelength-specific limiter includes a stack of wavelength-specific limiters configured to limit impinging light having a plurality of different wavelengths. The stack includes a plurality of wavelength-specific limiters. Each one of the plurality of wavelength-specific limiters is activated by a corresponding wavelength of the impinging light and is configured to limit the corresponding wavelength of the impinging light.