Compact Night Vision System Using Freeform Optics
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Solution Overview
Problem
Existing night vision systems are bulky due to their optimization for resolution and sensitivity rather than size and weight, limiting their portability and compactness.
Innovation Solution
The use of freeform optics and a compact integration of detectors and displays, including wedge-shaped lenses and a light detector module with a photocathode, microchannel plate, and phosphor-coated microlens array, allows for a direct line of sight and reduced size, enabling a portable night vision system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If state-of-the-art night vision devices are optimized for resolution and sensitivity, then image quality is improved, but size and weight increase making the system bulky
Solution Approach 1:
The optical system is divided into separate functional modules: objective lens, beam splitter, image intensifier, and eyepiece. This segmentation allows each component to be optimized independently and enables compact arrangement of the overall system, reducing total size while maintaining high resolution and sensitivity performance
Solution Approach 2:
The patent employs a nested configuration where the image intensifier is positioned within the optical path between the objective lens and eyepiece. The beam splitter is integrated into this nested structure, allowing multiple optical components to occupy overlapping spatial volumes, thereby minimizing the overall system footprint while preserving image quality
2Measurement precision
If state-of-the-art night vision devices are optimized for resolution and sensitivity, then image quality is improved, but the system becomes bulky
Solution Approach 1:
The patent utilizes a folded optical path design where light travels through multiple reflections and refractions in a non-linear trajectory. The beam splitter introduces angular deviations that fold the optical path into a compact three-dimensional arrangement, reducing the linear dimensions of the system while maintaining the required optical resolution and sensitivity
3Ease of manufacture
If conventional optics are used in night vision systems, then ease of manufacture is maintained, but portability and compactness are limited
Solution Approach 1:
The patent employs asymmetric optical designs in the objective lens and eyepiece configurations, deviating from conventional symmetric arrangements. This asymmetry allows for more efficient use of space and enables compact folding of the optical path, improving portability while using standard manufacturing techniques for each individual component
Solution Approach 2:
The beam splitter serves as an intermediary optical element that redirects light paths without requiring complex mechanical adjustments. This intermediary component enables compact system arrangement while maintaining ease of manufacture, as the beam splitter can be integrated using standard optical mounting techniques
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 results in a significantly more compact and portable night vision system with improved usability, reducing the overall volume and weight while maintaining effective image intensification and detection capabilities.
Implementation Method 1
Light is absorbed by the photocathode and converted to electrons
Implementation Method 2
electrons are amplified by the microchannel plate
Implementation Method 3
The electrons are then accelerated to the phosphor screen at high voltage (∼600-900V), resulting in the generation of more light
Implementation Method 4
a wedge-shaped, freeform objective as the collection optics and a wedge-shaped, freeform eyepiece as the display optics
Implementation Method 5
a second freeform surface configured to receive the light transmitted into the body of the eyepiece from the first freeform surface and configured to reflect the received light at the second surface
Data Source
AI summary
Night vision systems that are compact in size due to one or more of the design of the optical system and light detector module.