LED Lighting Device With Interference Filter For NVG Compatibility
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Solution Overview
Problem
Existing lighting systems for liquid crystal flat screens, particularly those using fluorescent tubes, face issues with obsolescence, high power consumption, and compatibility with environmental standards and night vision goggles (NVG), requiring complex optical filtering to prevent saturation of NVG amplification devices, especially for red light emission.
Innovation Solution
A lighting device using a carpet of light-emitting diodes with an interference filter above the red diodes, allowing adjustment of geometric and photometric parameters to ensure NVG compatibility and maintain correct colorimetry, featuring control means for day and night modes with filtered red diodes only active in night mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If red light-emitting diodes are used to illuminate the flat screen, then the colorimetry is improved and red color is accurately represented, but the night vision goggle compatibility deteriorates due to saturation of the amplification devices
Solution Approach 1:
The patent applies local quality by implementing different operational states for different spectral components of the same light source. The red LED is selectively filtered only during night vision mode, while full spectrum emission is maintained during daytime mode. This spatial and temporal differentiation allows the system to maintain accurate red colorimetry when needed while preventing NVG saturation during nighttime operation.
Solution Approach 2:
The patent implements dynamics by making the optical filtering characteristic changeable based on operational mode. The interference filter is selectively engaged only during night vision operation, allowing the system to dynamically adjust its spectral transmission properties. This enables the red LED to provide full colorimetric performance during daytime while automatically limiting red/near-infrared emission during nighttime to prevent NVG amplification device saturation.
2Object-affected harmful factors
If optical filters are added to fluorescent tube lighting to ensure NVG compatibility, then the NVG saturation problem is resolved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent employs a cost-effective LED-based lighting solution with integrated interference filtering, replacing the more complex and expensive fluorescent tube systems with filters. LEDs have longer operational life and lower maintenance requirements, while the interference filter provides effective NVG compatibility without the complexity of multiple optical components needed in fluorescent systems. The solid-state nature of LEDs simplifies the overall device architecture.
Solution Approach 2:
The patent achieves universality by designing a single lighting device that serves multiple functions: daytime illumination with full colorimetry, nighttime illumination with NVG compatibility, and automatic mode switching. The interference filter integrated with the LED assembly provides both color correction for red emission and NVG saturation prevention, eliminating the need for separate filtering systems and reducing overall device complexity compared to fluorescent tube approaches.
3Illumination intensity
If the intensity of red light is increased to improve colorimetry, then the red color representation is enhanced, but the power consumption increases
Solution Approach 1:
The patent applies partial action by selectively filtering only the problematic red and near-infrared spectral components during night vision mode, rather than attenuating the entire spectrum. This allows the LED to operate at full intensity for optimal colorimetry while the interference filter blocks only the specific wavelengths that cause NVG saturation. During daytime mode, no filtering is applied, maintaining full power efficiency and color accuracy without energy waste.
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 solution provides NVG compatibility and satisfactory colorimetry while reducing power consumption and complexity, adhering to strict standards like MIL STD 3009, ensuring accurate red color representation and efficient operation.
Implementation Method 1
an interference filter arranged above the diode, the filter having a determined diameter
Implementation Method 2
lighting device with light-emitting diodes
Implementation Method 3
light-emitting diodes comprising green diodes DG emitting in a first spectral band
Data Source
Figure 1~2
Figure 3
AI summary
The device has green LEDs (D-G), blue LEDs (D-B) and red LEDs (D-R) emitting light in spectral bands centered on a first wavelength situated in green, a second wavelength situated in blue and a third wavelength situated in red. An optical plate (1) is arranged above the LEDs. Zones of the plate above certain red LEDs comprise an interferential filter (2) whose optical transmission has cutoff wavelength situated in the red near 630 nanometers. Height (H) of the filter above the red LEDs and shape of the filter are chosen in a manner to partially filter light emitted by the red LEDs.