Light Conversion Sheet Edge Compensation for LCD Blue Light Leakage
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Solution Overview
Problem
Liquid crystal display (LCD) devices suffer from bluish light leakage at the edges due to insufficient conversion of blue light into red and green light, leading to image quality deterioration and uneven color gamut.
Innovation Solution
A backlight unit with a light guide plate and a light conversion sheet featuring a light compensation pattern along its edges, where the light conversion sheet has varying thickness and includes quantum dots to enhance the conversion of blue light into red and green light, thereby reducing bluish light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a light guide plate with edge-type LED backlight is used, then the LCD device becomes thinner and lighter with lower power consumption, but bluish light leakage occurs at the edges due to insufficient blue light conversion
Solution Approach 1:
The patent applies local quality by positioning light compensation patterns specifically at the edge regions of the light conversion sheet where bluish light leakage occurs. These patterns have different optical properties (higher refractive index) than the surrounding areas, creating localized light recycling zones that convert excess blue light into red and green wavelengths only where needed, rather than modifying the entire light conversion sheet
Solution Approach 2:
The light compensation patterns act as an intermediary element between the light guide plate and the liquid crystal display panel. These patterns mediate the interaction by capturing leaked blue light through total internal reflection and converting it into red and green light through quantum dot fluorescence, thereby preventing direct blue light leakage while maintaining overall white balance
2Illumination intensity
If quantum dots are used for light conversion, then color gamut is enhanced, but blue light leakage at edges persists due to uneven light conversion distribution
Solution Approach 1:
The patent addresses uniformity issues by creating local variations in the light conversion sheet structure. Light compensation patterns with different refractive indices are positioned specifically at edge regions where blue light leakage occurs, creating localized zones of enhanced light conversion without affecting the uniformity of the main display area
Solution Approach 2:
The patent introduces a new dimension of control by varying the thickness of the light conversion sheet at different locations. The light compensation patterns create localized thickness variations that enhance light conversion efficiency at edges where blue light leakage occurs, while maintaining uniform thickness in the central display area
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 solution enhances image quality and color gamut by effectively recycling and refracting blue light into white light, improving light efficiency and achieving better white balance across the display screen.
Implementation Method 1
a light conversion sheet having a first thickness within a first area and a second thickness within a second area, wherein the second area is the edges of the first area and the second thickness is thicker than the first thickness, wherein the light conversion layer including a first light conversion element configured to convert a portion of the blue light into a portion of green light and a second light conversion element configured to convert another portion of the blue light into a portion of a red light
Implementation Method 2
the edge type backlight unit includes a light guide plate disposed under the LCD panel and a light source disposed at least one side surface or edge of the light guide plate. In such an edge type backlight unit, light emitted from the light source is indirectly applied to the LCD panel as a result of the total internal reflection through the light guide plate
Data Source
AI summary
A liquid crystal display device is disclosed. The liquid crystal display device includes a liquid crystal display panel, a light guide plate configured to guide blue light from a blue light source to the liquid crystal display panel and a light conversion sheet comprising a light conversion layer and a light compensation pattern positioned on edges of the light conversion layer configured to compensate blue light leakage at the edges of the light conversion sheet, wherein the light conversion sheet is positioned between the liquid crystal display panel and the light guide panel.