Semi-Transparent UV Detector Array for Night Vision Image Sensing
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Solution Overview
Problem
Analog night vision systems face the challenge of detecting the NV image without attenuating the image provided to the user, as detecting the image requires intercepting or diverting light, which degrades the image quality.
Innovation Solution
The implementation of a photodetector that is transmissive to visible light and detects ultraviolet photons emitted by the phosphor screen, allowing the visible portion of the NV image to be transmitted without degradation, using a stacked microelectronic device with a transparent display that superimposes heads-up display information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a photodetector is placed in the optical pathway to detect the NV image, then the NV image can be detected and recorded, but the image quality provided to the user is attenuated due to light interception
Solution Approach 1:
The photodetector is designed with wavelength-selective properties, being highly absorptive to ultraviolet wavelengths (300-400 nm) while highly transmissive to visible wavelengths (400-750 nm). This local quality differentiation allows the detector to selectively detect UV photons from the phosphor screen without intercepting visible light that forms the NV image for the user, thereby resolving the contradiction between detection capability and image quality
Solution Approach 2:
The photodetector exhibits different optical properties at different wavelengths - it appears opaque to UV light (allowing detection) but transparent to visible light (allowing image transmission). This wavelength-dependent transparency/opacity behavior enables simultaneous UV detection and visible light transmission, eliminating the trade-off between detection and image quality
2Measurement precision
If conventional photodetectors are used to detect UV light, then UV photons can be detected, but visible light is also absorbed, degrading the NV image
Solution Approach 1:
The photodetector's optical properties are localized to specific wavelength ranges, with high UV absorptivity confined to the 300-400 nm range and high visible transmissivity in the 400-750 nm range. This spectral localization allows UV detection without visible light interference, resolving the contradiction between UV detection accuracy and visible light transmission
Solution Approach 2:
The photodetector is constructed using a composite structure including a semiconductor layer (such as silicon carbide or gallium nitride) that inherently provides wavelength-selective absorption characteristics. This composite material approach enables simultaneous UV sensitivity and visible transparency, eliminating the harmful effect of visible light attenuation
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 the detection of the NV image without adversely affecting the image quality seen by the user, by preferentially absorbing ultraviolet light and transmitting visible light, thus maintaining the intensity of the NV image provided to the user.
Implementation Method 1
the detector detects light within a second range of wavelengths (e.g., UV light) and transmits the light within the first range of wavelengths
Implementation Method 2
via the phenomenon of luminescence, the phosphor screen emits photons in response to radiant energy (e.g., the electrons)
Data Source
AI summary
An apparatus and method are provided for a night vision system that integrates functions of detecting an intensified image and transmitting the intensified image superimposed with a heads-up display. The night vision system includes an optical device having a transparent display configured with pixels emitting display light (i.e., the heads-up display), and the transparent display has transmission regions arranged among the pixels for transmitting light representing an intensified image (e.g., luminescent light from a phosphor screen). Light rays passing through the transmission regions also pass through detectors, which detect light outside of the visible spectrum (e.g., UV light). By detecting light outside of the visible spectrum, the detectors detect the intensified image without degrading the image in the visible spectrum that is provided to users.