Dual-Mode Infrared Filter for LCD Backlight Night Vision
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Solution Overview
Problem
Standard LCD displays emit high levels of IR radiation, which can interfere with night vision devices, and existing solutions either filter IR but reduce visible light intensity or require separate light sources for day and night modes, leading to inefficiencies.
Innovation Solution
A dual-mode infrared filter system that can be enabled or disabled based on the ambient light conditions, allowing IR filtering during night vision and full spectrum illumination during daylight, with multiple illumination sources for enhanced brightness in strong ambient light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an infrared filter is used to block IR radiation for night vision compatibility, then night vision compatibility is improved, but visible light intensity is reduced
Solution Approach 1:
The infrared filter is made movable between two positions: a first position where it blocks IR radiation for night vision compatibility, and a second position where it allows full visible light transmission. This dynamic repositioning resolves the contradiction by enabling the system to switch between night vision mode (filter enabled) and daylight mode (filter disabled), eliminating the need to permanently sacrifice visible light intensity.
Solution Approach 2:
The operation of the display system is segmented into distinct modes: night vision mode with IR filtering and daylight mode without filtering. The movable filter enables temporal segmentation where different optical configurations are applied at different times based on ambient lighting conditions, allowing both night vision compatibility and full visible light transmission to be achieved in their respective operational contexts.
2Object-affected harmful factors
If separate light sources are used for day and night modes, then night vision compatibility is improved, but device complexity increases
Solution Approach 1:
A single illumination source serves dual purposes: it provides full-spectrum illumination during daylight operation and works in conjunction with the movable IR filter during night vision operation. This eliminates the need for separate day and night light sources, reducing device complexity while maintaining night vision compatibility through the filter mechanism rather than through multiple illumination systems.
Solution Approach 2:
The day and night illumination functions are merged into a single illumination source that operates in both modes. The distinction between day and night operation is achieved not through separate light sources but through the selective application of the movable infrared filter, combining the illumination function with the filtering control mechanism into one integrated system.
3Object-affected harmful factors
If a fixed infrared filter is always positioned in the light path, then night vision compatibility is improved, but visibility during daytime is reduced
Solution Approach 1:
The infrared filter transitions from a fixed position to a dynamic, movable position that allows it to be selectively placed in or out of the light path. This enables the system to adapt to different lighting conditions: the filter is positioned to block IR radiation during night vision operation and repositioned to allow full visible light transmission during daylight operation, resolving the contradiction between night vision compatibility and daytime visibility.
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 efficient use of LCD displays in various lighting conditions by reducing IR interference for night vision while maintaining visibility and brightness during the day, using a dual-mode IR filter and multiple illumination sources.
Implementation Method 1
a dual-mode infrared filter configured to filter an infrared spectrum of light emanating from the illumination source
Implementation Method 2
allowing a complete spectrum of the light to reach the LCD panel
Data Source
AI summary
A backlight layer to be operatively coupled with an LCD panel, the backlight layer comprising: an illumination source configured to illuminate the LCD panel; a dual-mode infrared filter configured to filter an infrared spectrum of light emanating from the illumination source, wherein: when the dual-mode infrared filter is in an enabled mode, the dual-mode infrared filter is positioned in the path of the light emanating from the illumination source and before the light reaches the LCD panel, thereby filtering an infrared spectrum of the light, and when the dual-mode infrared filter is in a disabled mode, the dual-mode infrared filter is positioned out of the path of light emanating from the illumination source, thereby allowing a complete spectrum of the light to reach the LCD panel.