Semi-Transparent Detector Array for Night Vision Dynamic Range
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Solution Overview
Problem
Traditional nightvision systems have a limited dynamic range, which causes dimly illuminated objects to be obscured when brightly illuminated objects are present in the same scene, leading to loss of detail and contrast issues.
Innovation Solution
The implementation of a nightvision system that includes a transparent optical device optically coupled to an underlying device, such as an image intensifier. This system uses a semiconductor chip with active elements and transparent regions to transmit light while detecting brightness maps, and a tunable filter array to filter input light based on processed brightness maps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a traditional nightvision system with automatic brightness control is used, then the system can operate in low-light environments, but the dynamic range is limited and dimly illuminated objects are obscured when brightly illuminated objects are present
Solution Approach 1:
The patent segments the optical path into multiple spectral channels using a dispersive element (prism or grating) to separate light into different wavelength ranges. This allows different portions of the spectrum to be processed independently, with bright objects in certain wavelengths not overwhelming dim objects in other wavelengths, thereby expanding the effective dynamic range.
Solution Approach 2:
The patent introduces an intermediary spectral processing stage between the scene and the detector. The dispersive element acts as a mediator that redistributes spectral information across multiple detectors, allowing the system to capture both bright and dim objects simultaneously by assigning different spectral bands to different detection channels.
2Illumination intensity
If automatic brightness control mechanisms are applied, then the system compensates for bright light sources, but extreme automatic dimming causes details to be lost and the scene to be washed out
Solution Approach 1:
By segmenting the spectral information across multiple detectors, the system avoids applying uniform dimming to the entire scene. Instead, each detector channel processes its specific spectral band independently, preserving details in dimly illuminated regions while allowing bright regions to be captured in their appropriate spectral channels without causing overall scene washout.
Solution Approach 2:
The patent changes the parameter being controlled from overall brightness (intensity) to spectral distribution. Rather than uniformly dimming the entire image when bright objects are present, the system redistributes spectral information across multiple channels, maintaining detail preservation through spectral parameter manipulation rather than simple intensity attenuation.
3Measurement precision
If a transparent optical device with active elements is used, then light detection capability is provided, but the device complexity increases with the addition of semiconductor chip structures
Solution Approach 1:
The patent employs a universal semiconductor detector platform that performs multiple functions: it detects light intensity, provides spectral information through the dispersive element, and enables multi-channel processing. This multi-functional approach consolidates what would otherwise require separate components into a single integrated detector array, managing complexity through functional consolidation.
Solution Approach 2:
The patent replaces complex mechanical spectral filtering systems with an integrated semiconductor detector approach combined with a dispersive element. Instead of using multiple mechanical filters or moving parts to achieve spectral separation and detection, the system uses optical dispersion combined with fixed semiconductor detectors, eliminating mechanical complexity while maintaining detection precision.
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 system improves contrast and highlights objects by filtering out excessive light, thereby enhancing the dynamic range and reducing halo obscurance, allowing for better detection and recognition of objects in mixed brightness environments.
Implementation Method 1
When photons strike the photocathode, electrons are emitted into a vacuum tube
Implementation Method 2
The phosphor screen is typically chosen such that it emits human visible light when the amplified electrons strike the phosphor screen
Data Source
AI summary
A nightvision system includes an underlying device that provides output light in a first spectrum. A transparent optical device transmits light in the first spectrum from the underlying device through the transparent optical device. The transparent optical device includes an active area of a semiconductor chip. The active area includes active elements that cause the underlying device to detect light from the underlying device and transparent regions formed in the active area which are transparent to the light in the first spectrum to allow light in the first spectrum to pass through from the underlying device to a user. An image processor processes brightness maps produced using light detected by the first plurality of active elements. A tunable filter array coupled to the image processor filters at least a portion of the input light into the underlying device the underlying device based on brightness map processing.