Overlay Display Brightness Modulation for Balanced Night Vision
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Solution Overview
Problem
Analog night vision systems face challenges in balancing the intensity of overlay display light with the intensified image, leading to situations where one image overwhelms the other, making it difficult for users to discern both images effectively in varying light environments.
Innovation Solution
The implementation of an optical device with semiconductor chips and electro-optical circuits that include light emitters and detectors, which adjust the intensity of the display light based on the detected intensity of the direct-view light, ensuring balanced relative intensities between the display and intensified images through spatial modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the intensity amplitude of the display light is kept constant, then the display image can be clearly seen in some conditions, but the display light will overwhelm the intensified light in low-light environments, making the intensified image difficult to see
Solution Approach 1:
The display light intensity is made dynamic rather than constant. The system continuously adjusts the intensity amplitude of the display light based on real-time detection of environmental light conditions and intensified light levels, allowing the display to adapt to varying brightness conditions in the night vision environment
Solution Approach 2:
A feedback mechanism is implemented where detectors measure the intensity of the intensified light and this information is used to automatically adjust the display light intensity. The system uses the detected intensified light signal to modulate the display light amplitude, creating a closed-loop control system that balances the two light sources
2Illumination intensity
If the intensity amplitude of the display light is increased to ensure visibility, then the display image becomes clearly visible, but the display light overwhelms the intensified light in low-light areas, making parts of the intensified image difficult to see
Solution Approach 1:
The system applies different intensity levels of display light to different spatial regions based on local conditions. The intensity amplitude is modulated locally across the display area, allowing the display to be brighter in regions where intensified light is stronger and dimmer in regions where intensified light is weaker, preserving information across the entire field of view
Solution Approach 2:
The intensity parameter of the display light is continuously changed based on the detected intensified light signal. The system modulates the amplitude parameter of the display light in response to variations in intensified light intensity, dynamically adjusting the display brightness to maintain visibility balance
3Device complexity
If constant intensity display light is used, then the display structure remains simple, but the system cannot adapt to varying light conditions, making it difficult to see both images effectively
Solution Approach 1:
A feedback control system is implemented where detectors continuously monitor the intensified light intensity and this information feeds back to automatically adjust the display light intensity amplitude. This closed-loop mechanism enables the system to adapt to varying environmental conditions without requiring complex manual controls or multiple discrete 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
This solution allows for a user-friendly combined image by dynamically adjusting the display light intensity to match the intensity of the intensified image, preventing either image from overpowering the other, thereby enhancing visibility of both in diverse lighting conditions.
Implementation Method 1
The image intensifier has a photocathode that emits electrons in response to incident photons
Implementation Method 2
The multiplied electrons then strike a phosphor screen, and, via the phenomenon of luminescence, the phosphor screen emits photons in response to radiant energy
Data Source
AI summary
An apparatus and method are provided for a night vision system including a transparent overlay display that transmit direct-view light representing an intensified image and emits display light representing a display image. The overlay display includes photodetectors arranged to detect an intensity of the incoming direct-view light, and an intensity of the display light depends on the detected intensity. In some embodiments, the intensity of the display light is spatially modulated using an amplitude or envelope of the intensity that is based on the detected local intensity of the direct-view light. In some embodiments, the intensity of the display light is adjusted to correct for loss of the direct-view light. The intensity of the display light may be controlled using control circuitry that receives signals from the photodetectors, and the control circuitry may be located on the same semiconductor chip as the overlay display.