Thermal Reflex Sight Beam Combiner for Low-Light Aiming
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Solution Overview
Problem
Firearm aiming sights face challenges in effectively superimposing thermal or digital images onto a direct view of a target scene, especially under low light conditions, and in providing enhanced visibility through various spectral bands without degrading the direct view.
Innovation Solution
A thermal reflex sight that combines a beam combiner with reflective surfaces and an afocal eyepiece to overlay digital or intensified images onto a direct view, using a shared housing or separate components mounted on a firearm, allowing for unity magnification or attachment to a telescopic sight, and employing digital cameras or image intensifiers sensitive to various spectral ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a thermal imaging camera or image intensifier is used to capture and display images, then night-time vision and detection through obscurants is enhanced, but the direct view of the target scene is degraded or blocked
Solution Approach 1:
The optical system is segmented into multiple optical paths: a direct view path that allows unobstructed viewing of the target scene, and an imaging path that captures thermal or intensified images. The beam combiner prism separates and recombines these paths, allowing both functions to operate simultaneously without interfering with each other.
Solution Approach 2:
A beam combiner prism acts as an intermediary optical element that merges the direct view light path with the imaging path. The prism combines the transmitted light from the target scene with the light from the imaging system, allowing both images to be superimposed without blocking either path.
2Reliability
If an image from a camera or intensifier is superimposed on the direct view image, then target detection is enhanced, but the complexity of the optical system increases
Solution Approach 1:
The direct view optical path and the imaging optical path are merged into a single coaxial alignment using a beam combiner prism. Both the direct view image and the thermal/intensified image are superimposed on the same field of view, allowing the user to see both images simultaneously through a single optical channel.
Solution Approach 2:
The optical system is designed to perform multiple functions through a unified structure: it provides direct viewing capability, thermal imaging capability, and intensified imaging capability all through a single optical path. The beam combiner prism enables the system to handle multiple light paths and superimpose them, creating a multi-functional aiming sight.
3Measurement precision
If magnification is increased to enhance target visibility, then target detail is improved, but the field of view and direct view quality are reduced
Solution Approach 1:
The system provides dynamic viewing options where the user can switch between direct view mode (full field of view, no magnification) and imaging mode (magnified view through the camera or intensifier). The afocal eyepiece system allows for adjustable magnification while maintaining a comfortable eye relief and field of view appropriate for each mode.
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
Enables clear and enhanced visualization of target scenes in low light conditions by superimposing thermal or digital images onto the direct view, maintaining high light transmission and brightness, and accommodating various spectral bands for improved aiming accuracy.
Implementation Method 1
A thermal reflex sight fuses (superimposes) an image of a target scene from a thermal or other digital camera or an image of the target scene from an image intensifier onto a direct view of the target scene. The reflex sight comprises two apertures. One aperture is a direct view optical path of the target scene. The other aperture is the objective lens for the digital camera or image intensifier. A beam combiner with two reflective surfaces (for example, a Bauernfeind, Penta, or other prism bonded to a wedge prism) and an afocal eyepiece overlay the digital image or intensified image of the target scene onto the direct view scene with matched magnification.
Data Source
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AI summary
A reflex sight comprises two apertures. One aperture is a direct view optical path of the target scene. The other aperture is a digital (e.g., thermal) camera or image intensifier. A beam combiner with two reflective surfaces (for example, a Bauernfeind, Penta, or other prism bonded to a wedge prism) and afocal eyepiece optics overlay the digital image or intensified image onto the direct view scene with matched magnification.