Integrated Grating and Filter for Holographic Sight Glare Reduction
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Solution Overview
Problem
Existing holographic sights face issues with environmental durability and lack of angular and wavelength selectivity, as well as interference from unfiltered ambient light causing glare, which affects the visibility of the reticle image.
Innovation Solution
An integrated grating and filter device is used within the holographic sight, comprising a base substrate, transparent substrate, and dyed epoxy, with a reflective coating that diffracts light and inhibits certain wavelengths of ambient light from reaching the hologram, reducing glare without increasing the sight's size or weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If emulsion-based holographic volume phase gratings are used to achieve wavelength selectivity, then angular and wavelength selectivity are improved, but environmental durability deteriorates
Solution Approach 1:
The patent combines a durable ruled metal-on-glass grating with an emulsion-based holographic volume phase grating to create a composite structure. The metal-on-glass grating provides environmental durability while the holographic VPG layer provides wavelength selectivity. This composite approach allows both functions to coexist without compromising either durability or selectivity.
2Reliability
If ruled metal-on-glass gratings are used to achieve durability, then environmental durability is improved, but angular and wavelength selectivity deteriorates
Solution Approach 1:
The patent combines a durable ruled metal-on-glass grating with an emulsion-based holographic volume phase grating to create a composite structure. The metal-on-glass grating provides environmental durability while the holographic VPG layer provides wavelength selectivity. This composite approach allows both functions to coexist without compromising either durability or selectivity.
3Measurement precision
If order-sorting filters are added to eliminate higher diffraction orders, then angular selectivity is improved, but device complexity increases
Solution Approach 1:
The patent merges the grating and filter functions into a single integrated component. The holographic VPG layer is applied directly to the metal-on-glass grating, combining the diffraction function with the wavelength selection function in one element. This eliminates the need for separate order-sorting filters and reduces the overall number of parts in the optical system.
4Device complexity
If unfiltered ambient light enters the housing, then the sight remains simple and compact, but harmful factors increase due to glare and rainbow effects
Solution Approach 1:
The patent uses the ambient light itself to create the filtering effect. The holographic VPG layer is designed to diffract and separate wavelengths, causing the ambient light to create interference patterns that naturally block certain wavelengths from reaching the user's eye. This converts the potentially harmful ambient light into a useful filtering mechanism without adding separate filter components.
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 integrated grating and filter device effectively reduces ambient light interference, enhancing the visibility of the reticle image by filtering out unwanted wavelengths, thereby improving the sight's durability and performance while maintaining a compact design.
Implementation Method 1
The diffraction grating spatially directs light in the laser beam as the wavelength changes with temperature
Implementation Method 2
The dyed epoxy is adapted to inhibit at least a portion of the light from reflecting to the hologram
Data Source
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AI summary
A holographic sight is provided having a housing that includes a plurality of holograph sight components. A laser diode mounted in the housing is configured to emit a laser light beam. The light beam is transmitted to an integrated diffraction grating and filter unit which includes a grating and a filter in a single device. The diffraction grating has a grating surface for diffracting the light beam and also diffracting unwanted ambient light transmitted into the housing. The filter is an optical filter contacting at least a portion of the grating. The optical filter is adapted to absorb at least one wavelength of the ambient light to inhibit the ambient light from diffracting into a visible spectrum that might otherwise be viewable to a user looking into the holographic sight.