Backlight Unit Air Gap Prevents Green Light Absorption
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Solution Overview
Problem
In liquid crystal display devices, the overlap of green and red light emission areas leads to reduced luminance due to absorption of green light by red fluorescent materials, resulting in inefficient light utilization and reduced brightness.
Innovation Solution
A backlight unit with a color conversion layer that converts blue light into green light, using a green light emitting material, and an air gap between the color conversion layer and optical sheet to prevent overlap with green pixels, ensuring that green light is not absorbed by red pixels, thereby increasing luminance and spatially separating red and green light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If green fluorescent material is used to generate green light by absorbing blue light, then green light emission is achieved, but the green light is absorbed by red fluorescent material in the overlapping area, reducing luminance
Solution Approach 1:
The patent divides the backlight unit into distinct regions: a first region with blue light sources and green fluorescent material, and a second region with red fluorescent material. This spatial segmentation prevents the overlap between green light emission and red fluorescent material absorption areas, eliminating the energy loss while maintaining green light emission intensity.
Solution Approach 2:
The patent applies different fluorescent materials with specific spectral characteristics to different locations within the backlight unit. The green fluorescent material is positioned where blue light is emitted, while the red fluorescent material is positioned in a separate area. This local optimization ensures that each material operates in its optimal spectral environment without interfering with other light emissions.
2Illumination intensity
If red fluorescent material is used to generate red light by absorbing blue light, then red light emission is achieved, but it absorbs green light in the overlapping area, reducing overall luminance
Solution Approach 1:
The patent spatially separates the red fluorescent material from the green light emission area by creating distinct first and second regions. This segmentation ensures that the red fluorescent material only receives blue light for conversion to red light, without being exposed to green light that would be absorbed, thereby eliminating the harmful effect while maintaining red light emission.
Solution Approach 2:
The patent introduces a structural intermediary (the spatial arrangement and positioning of fluorescent materials) that prevents direct interaction between green light and red fluorescent material. This intermediary configuration allows both red and green light emissions to coexist without mutual interference, resolving the harmful absorption effect.
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 configuration enhances light efficiency by preventing the absorption of green light by red light emitting materials, increasing the brightness and color reproduction range of the liquid crystal display device, while maintaining high luminance and adhering to BT.2020 color reproduction standards.
Implementation Method 1
the green light is generated by absorbing, by a green fluorescent material, the blue light
Implementation Method 2
the red light is generated by absorbing, by a red fluorescent material, the blue light
Data Source
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AI summary
The present disclosure relates to a backlight unit and a liquid crystal display device. The liquid crystal display device includes a display panel including a red pixel, a green pixel, and a blue pixel; and a backlight unit which emits light to the display panel, wherein the backlight unit includes: a light source providing a first color light; a color conversion layer disposed on the light source and converting a part of the first color light into a second color light; an optical sheet between the display panel and the color conversion layer; and an air gap between the color conversion layer and the optical sheet.