Reflecting Filter on Absorbing Substrate for Laser Protection
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Solution Overview
Problem
Current laser protective devices, such as eyewear and surveillance camera filters, face challenges in effectively blocking high power laser wavelengths without significantly reducing visible light transmission or causing color discrimination issues, and often suffer from degradation due to high intensity light exposure.
Innovation Solution
A laser protective device featuring a transparent substrate with a reflecting filter coated on one or both sides, designed to reflect specific laser wavelengths while transmitting most non-laser wavelengths, ensuring good color discrimination and minimal impact on normal operation, and optionally incorporating an absorbing substrate for enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If absorbing substrates or lenses with dyes are used to block laser wavelengths, then laser blocking protection is achieved, but visible light transmission and color discrimination are significantly reduced
Solution Approach 1:
The optical filter is segmented into multiple functional layers: a first optical layer with first dye absorbing at a first laser wavelength, and a second optical layer with second dye absorbing at a second laser wavelength. Each layer is optimized for specific wavelength ranges, allowing selective blocking of laser lines while maintaining transmission in other spectral regions. This segmentation enables targeted protection without broad-spectrum visible light loss.
Solution Approach 2:
Different regions of the optical filter have different absorption characteristics tailored to specific needs. The first and second optical layers have distinct dye compositions and absorption spectra, creating local quality variations that block specific laser wavelengths while preserving visible light transmission in other wavelength regions. This allows the filter to have high optical density at laser wavelengths while maintaining good luminance transmittance overall.
2Object-affected harmful factors
If absorbing substrates with dyes are used to block laser wavelengths, then laser blocking is achieved, but the absorption material breaks down after high intensity light exposure
Solution Approach 1:
The patent employs multiple optical layers with different dye compositions as a preemptive measure against dye breakdown. When one dye layer degrades from high intensity exposure, the other layers continue to provide protection. This redundant multi-layer structure cushions against the reliability issue of individual dye breakdown, ensuring sustained laser blocking protection over time.
Solution Approach 2:
The optical filter uses composite material structure with multiple dye-containing layers, each with different absorption characteristics. This composite approach combines the advantages of different dye materials while mitigating their individual weaknesses, particularly regarding photostability. The layered composite structure provides both laser blocking protection and improved durability through material diversity.
3Object-affected harmful factors
If absorbing substrates are used to block laser wavelengths, then laser blocking is achieved, but reflection of ambient light back into the user's eye is not reduced
Solution Approach 1:
Instead of relying solely on absorption to block light, the patent inverts the approach by using reflective coatings on the outer surfaces of the substrate. These reflective layers bounce ambient light away before it can enter the eye, while the absorbing dyes inside the substrate handle laser wavelength blocking. This inverted combination of reflection and absorption addresses both harmful factors effectively.
4Ease of manufacture
If a single optical layer with dye is used, then manufacturing is simple, but wavelength selectivity is poor
Solution Approach 1:
The optical filter is divided into multiple discrete optical layers, each containing dyes with specific absorption characteristics for particular wavelength ranges. This segmentation allows each layer to be optimized for specific laser line blocking, achieving high wavelength selectivity. While more complex than a single layer, the modular segmented structure maintains reasonable manufacturing feasibility through standardized layer deposition processes.
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 minimizes the intensity of laser light reaching the eye or device, maintaining high luminance and color discrimination, and reduces the risk of impairment from high power lasers, allowing users to function normally in various light conditions and ensuring devices like surveillance cameras can operate effectively.
Implementation Method 1
a reflecting filter deposited on one or both sides of the transparent substrate configured to substantially reflect one or more laser wavelengths while substantially transmitting most non-laser wavelengths
Implementation Method 2
absorbing substrates or lenses, typically based on dyes introduced into glass or plastic substrate material which are formulated to provide some blocking at one or more laser wavelengths through absorption
Data Source
AI summary
A laser reflecting has a low transmittance at one or more laser wavelengths while substantially transmitting all other wavelengths in the spectral range of interest, is coated on one or both sides of an absorbing or non-absorbing substrate. A laser reflecting filter on both sides of an absorbing substrate can result in an enhancement of the absorption of laser light by multiple reflections of the laser light in the absorbing substrate. The high transmittance of the laser-reflecting filter at non-laser wavelengths results in a relatively high overall transmittance through the coated substrate. In the specific case of laser reflecting coatings on a lens to protect an eye, this allows a high luminous transmittance and good color discrimination.