Reflex Sight Polarizing Beam Splitter Concealment
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Solution Overview
Problem
Conventional reflex sights allow the red dot to be visible not only to the shooter but also to the intended target, potentially compromising the shooter's safety, especially under low-light conditions, and are not effectively concealed from night vision devices.
Innovation Solution
The reflex visor incorporates a polarizing beam splitter layer or band stop filter between the coupling optics and the viewing opening, ensuring that the target mark is only visible from the viewing opening and not from outside, preventing detection by the target or night vision devices, while maintaining a compact and lightweight design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the target mark is made visible through the viewing opening for the shooter, then the shooter can aim accurately, but the target mark becomes visible to the intended target and compromises shooter safety
Solution Approach 1:
A polarizing beam splitter layer is introduced as an intermediary optical element between the target mark and the viewing opening. This layer allows the shooter to see the target mark through polarized light while blocking the transmission of the target mark image to the exterior, thus mediating between the need for visibility and the need for concealment
Solution Approach 2:
The patent utilizes polarized light properties to create direction-dependent visibility. The target mark appears normally polarized to the shooter viewing through the opening, but appears dark or invisible when viewed from the exterior at certain angles, effectively using optical property changes to resolve the visibility contradiction
2Illumination intensity
If the light source brightness is increased to improve visibility of the target mark, then the shooter can see the target mark clearly, but the target mark becomes more detectable by night vision devices
Solution Approach 1:
The polarizing beam splitter layer acts as a selective intermediary that transmits polarized light from the target mark to the shooter while blocking the transmission of this light to the exterior. This allows the light source to operate at sufficient brightness for shooter visibility without proportionally increasing detectability by external observers including night vision devices
Solution Approach 2:
The patent changes the optical parameters of light transmission by introducing polarization filtering. The target mark is illuminated with sufficient intensity for shooter visibility, but the polarizing layer modifies the light's transmission properties in different directions, reducing the intensity of light reaching external observers while maintaining adequate intensity for the shooter
3Object-affected harmful factors
If a reflective coating is applied to the lens to prevent light deflection towards the viewing opening, then the target mark is concealed from outside, but the device complexity increases
Solution Approach 1:
Instead of using complex reflective coatings, the patent employs a polarizing beam splitter layer that utilizes polarization properties of light. This layer is simpler in construction than reflective coatings while achieving the same concealment function by allowing light transmission in one direction (to the shooter) while blocking it in the opposite direction (to the exterior)
Solution Approach 2:
The patent replaces the mechanical/optical approach of reflective coatings with an optical field-based approach using polarized light. The polarizing beam splitter layer uses the polarization state of light to control direction-dependent visibility, substituting a simpler optical element for a more complex coating system
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
This configuration enhances the shooter's safety by preventing the red dot from being visible to the target, even with night vision devices, and allows for adjustable brightness and easy handling, making it suitable for various lighting conditions and environments.
Implementation Method 1
one of the means is designed such that the target mark is coupled into the beam path along the optical axis only in one direction towards the viewing opening
Implementation Method 2
a polarizing beam splitter layer between the coupling optics and the viewing opening
Implementation Method 3
a band stop filter between the coupling optics and the viewing opening that blocks the wavelength range emitted by the light source in the direction of the viewing opening
Implementation Method 4
projection device with collimation optics that focuses the reticle at infinity
Implementation Method 5
A lens optic (collimator) ensures that this reticle appears to the shooter at infinity
Implementation Method 6
a semi-transparent mirror that reflects the illuminated dot into the shooter's eye while allowing the shooter to see through it to the target
Data Source
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AI summary
A reflex sight (10) has a housing (20) with a viewing aperture (21) and a sighting aperture (22) along an optical axis (A). It also has a projection device (40) that images the light generated by a light source (50) as a target mark (Z), and a coupling optic (60) that couples the target mark (Z) imaged by the projection device (40) into the beam path along the optical axis (A). To prevent the target mark (Z) from being visible from the targeted object, the invention provides for at least one means (61, 62) by which the target mark (Z) imaged by the projection device (40) is essentially only visible from the viewing aperture (21). The means (61, 62) can be a polarizing beam splitter layer (61) configured as a boundary layer (65) between two prisms (63, 64).Alternatively, a bandstop filter (62) can be used, which is arranged between the coupling optics (60) and the viewing aperture (22) and prevents light reflected from the coupling optics (60) from being blocked or filtered out towards the viewing aperture (22). To achieve a cost-effective and easy-to-manufacture design of the sight (10), the components (40, 50, 60, 70, 80, 90, 100) of the sight (10) are designed as prefabricated assemblies that can be quickly and precisely mounted in the housing (20).