Night Vision Compatible Display Backlight Using Selective LED Arrays
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Solution Overview
Problem
Existing LCD display backlights, particularly those using fluorescent tubes, face issues such as high voltage requirements, fragility, unexpected failures, limited brightness control, and increased costs due to the need for filters to comply with night vision standards, which also reduce display intensity and affect visible light transmission.
Innovation Solution
A backlight system utilizing an array of LEDs, including orange, green, and blue LEDs, with a controller to selectively illuminate different sets of LEDs based on operating modes, eliminating the need for filters by adjusting the spectral output to meet night vision standards without compromising display intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If filters are used to meet night vision standards, then night vision compatibility is improved, but display intensity is reduced by 10 to 20 percent
Solution Approach 1:
The patent extracts and removes the harmful infrared radiation component from the backlight spectrum by selecting LEDs with specific wavelength characteristics that do not emit in the 620-930nm range. This eliminates the need for filters while preserving full visible light output intensity.
Solution Approach 2:
The patent applies local quality by using LEDs with specific spectral characteristics tailored for night vision compatibility. The backlight uses orange LEDs (590-650nm) that emit in the visible range but stop before entering the harmful infrared band, providing localized spectral optimization without affecting overall display brightness.
2Object-affected harmful factors
If filters are used to meet night vision standards, then night vision compatibility is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts and removes the harmful infrared radiation component from the backlight spectrum by selecting LEDs with specific wavelength characteristics that do not emit in the 620-930nm range. This eliminates the need for filters while preserving full visible light output intensity.
Solution Approach 2:
The patent replaces expensive optical filters with relatively inexpensive LED components that inherently provide the desired spectral characteristics. The use of standard orange, green, and blue LEDs is more cost-effective than implementing complex filter systems.
3Illumination intensity
If fluorescent tube backlights are used, then broad color spectrum output is achieved, but high voltage power supply and fragility issues occur
Solution Approach 1:
The patent replaces the mechanical fluorescent tube system with solid-state LED technology. This substitution eliminates fragile glass tubes and high voltage power supplies while providing equivalent or superior color spectrum output through combinations of orange, green, and blue LEDs.
Solution Approach 2:
The patent changes the fundamental operating parameters from high voltage fluorescent excitation to low voltage LED electroluminescence. The color spectrum is achieved through selective LED wavelength emission rather than broad fluorescent emission, providing both reliability and color quality.
4Object-affected harmful factors
If automatic gain control is activated to protect from bloom, then night vision system is protected, but sensitivity to nighttime objects decreases
Solution Approach 1:
The patent applies preliminary anti-action by preventing the harmful radiation from occurring in the first place. By using LEDs that do not emit in the 620-930nm range, the system preemptively eliminates the cause of bloom, making AGC protection unnecessary and preserving full NVS sensitivity.
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 LED-based backlight system meets night vision standards without requiring filters, maintaining display intensity and reducing power consumption, thus avoiding the heat and cost issues associated with filter usage, while providing adjustable illumination for various viewing conditions.
Implementation Method 1
A backlight for an LCD screen includes an array of LEDs and a controller
Implementation Method 2
a controller to selectively illuminate different sets of LEDs based on operating modes
Data Source
AI summary
A system and method of backlighting a display using LEDs is night vision viewing compatible and requires no filters. The backlight includes an array of LEDs and a controller configured to selectively illuminate the LEDs in the array. The array of LEDs includes orange LEDs that are illuminated during a night vision viewing mode and may include red LEDs that are illuminated in a non-night vision viewing mode.