Split NVIS Interference Filters for Lower-Layer Aviation Displays
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Solution Overview
Problem
Conventional NVIS filters for aviation displays are complex and expensive due to their multi-layered structure, which impairs pilot vision and increases production costs.
Innovation Solution
A split NVIS filter design is implemented, comprising two interference filters positioned before and after a diffuser in the display, reducing the number of layers to 30 each, thereby simplifying manufacturing and lowering costs while maintaining high performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single high-performance NVIS filter with more than 80 coating layers is used, then infrared filtering performance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent divides a single complex NVIS filter (80+ layers) into two separate interference filters with fewer layers each. The first filter is positioned between the backlight and diffuser, and the second filter is positioned between the diffuser and LCD stack. This segmentation reduces manufacturing complexity while maintaining the required infrared filtering performance through distributed wavelength blocking.
2Reliability
If a single high-performance NVIS filter with more than 80 coating layers is used, then infrared filtering performance is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the complex filter into two simpler filters that are easier to manufacture with fewer coating layers each. This reduces production time, material costs, and manufacturing difficulty while achieving the same NVIS compliance through the combined effect of both filters in the optical path.
3Object-affected harmful factors
If conventional NVIS filters are used, then bloom effect is reduced, but visibility through goggles is impaired
Solution Approach 1:
The patent applies different filtering characteristics to different parts of the optical path by positioning two filters with complementary wavelength blocking profiles. The first filter blocks certain infrared wavelengths while the second filter blocks overlapping and adjacent wavelengths, creating a distributed filtering system that reduces bloom while preserving visible light transmission for goggle compatibility.
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 split filter design achieves superior NVIS performance with reduced material costs and improved visibility, meeting NVIS compliance standards while minimizing interference with night vision goggles.
Implementation Method 1
The first interference filter comprises a first cutoff wavelength and a second cutoff wavelength. The second cutoff wavelength of the first interference filter is greater than the first cutoff wavelength of the first interference filter.
Implementation Method 2
The second interference filter comprises a first cutoff wavelength. The first cutoff wavelength of the second interference filter is between the first cutoff wavelength of the first interference filter and the second cutoff wavelength of the first interference filter.
Implementation Method 3
A display is disclosed, in accordance with one or more embodiments of the present disclosure. The display includes a backlight comprising one or more light emitting diodes (LEDs) configured to generate light.
Data Source
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AI summary
A display includes a split night visions imaging system (NVIS) filter, including a first and second interference filter (208). The first interference filter (204) is disposed between a backlight (202) and a diffuser (206) of the display. The second interference filter (208) is disposed between the diffuser (206) and an LCD stack of the display. A cutoff wavelength of the second interference filter (208) is between cutoff wavelengths of the first interference filter (204).