NVIS Color Filter with Integrated NIR Blocking
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Solution Overview
Problem
Conventional liquid crystal displays (LCDs) used in night vision imaging systems (NVIS) emit energy in the NVIS sensitive region, causing near-infrared sensitive goggles to 'bloom' and reducing their effectiveness, and existing solutions like external NVIS filters are costly and reduce visible light transmission, limiting color gamut and requiring structural modifications.
Innovation Solution
Incorporating a near-infrared (NIR) filter directly into the LCD color filter, which selectively absorbs NIR radiation between 650 nm and 930 nm while maintaining high visible light transmission, thus eliminating the need for external optical filters and dual mode backlights, and allowing for full color spectral output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an external NVIS filter is used to block NIR radiation, then NVIS compatibility is achieved, but visible light transmission is reduced and device complexity increases
Solution Approach 1:
The patent merges the NVIS filtering function with the existing color filter layer by incorporating NIR-absorbing materials into the color filter formulation. This integration eliminates the need for separate external NVIS filters while maintaining both visible light transmission and NIR blocking capabilities through a unified multi-functional layer.
Solution Approach 2:
The patent uses composite materials by formulating the color filter with a combination of conventional colorants and NIR-absorbing materials. This composite formulation enables the single layer to perform both color filtering and NIR radiation blocking, resolving the contradiction between visible light transmission and NIR protection.
2Object-affected harmful factors
If an external NVIS filter is mounted on the LCD panel, then NVIS compatibility is achieved, but device thickness increases and manufacturing cost increases
Solution Approach 1:
The patent combines the NVIS filter function with the existing color filter layer, eliminating the need for additional external filter components. This integration maintains the original display device thickness while achieving NVIS compatibility through the modified color filter formulation.
3Object-affected harmful factors
If conventional absorptive NVIS filters are used, then NIR radiation is blocked, but manufacturing cost increases and assembly complexity increases
Solution Approach 1:
The patent merges NVIS filtering functionality into the existing color filter manufacturing process by incorporating NIR-absorbing materials during the color filter fabrication. This integration eliminates separate NVIS filter assembly steps and reduces manufacturing costs by utilizing the existing production infrastructure.
Solution Approach 2:
The patent makes the color filter layer multi-functional by enabling it to perform both its traditional color separation function and the additional function of NIR radiation blocking. This universality eliminates the need for dedicated NVIS filter components and simplifies the overall manufacturing process.
4Object-affected harmful factors
If a dual mode backlight with NVIS backlight and normal mode backlight is used, then NVIS compatibility is achieved, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent extracts the NIR blocking function from the complex dual-mode backlight system and relocates it to the color filter layer. This extraction simplifies the backlight system to a single normal-mode backlight while achieving NVIS compatibility through the modified color filter, thereby reducing overall system complexity.
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 approach simplifies the design and manufacturing of NVIS-compatible LCDs by enhancing visible light transmittance and chromaticity, reducing costs, and maintaining display luminance without adding thickness, while effectively blocking over 80% of NIR radiation, ensuring compliance with MIL-STD-3009 standards.
Implementation Method 1
The color filter includes a NIR absorbing material, that selectively absorbs light in NVIS sensitive region from approximately 650 nm to 930 nm
Data Source
AI summary
A night vision imaging system (NVIS) compatible liquid crystal display (LCD) includes a backlight and an LCD panel. The LCD panel includes a color filter including a plurality of colored pixels. Each of the colored pixels in the plurality of colored pixels incorporates a near infrared (NIR) filter, capable of substantially blocking emissions from the backlight, including NIR emission between 650 nm and 930 nm, while maintaining high transmission of bands of visible light for producing a full color visual image.