Optical Sheet Luminance Equalization for LCD Bright Line Prevention
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Solution Overview
Problem
Reducing the width of the frame in liquid crystal display devices to increase the display screen area is hindered by the visibility issues caused by the bright line prevention region, which appears on the display screen due to expansion and contraction of the optical sheet and dimensional tolerances during assembly.
Innovation Solution
An optical sheet with a luminance equalization region on one surface, featuring a colored portion and a light-transmitting portion that surrounds the colored portion, is used to absorb high-intensity light and hot spots, with the colored portion having a width of 10 μm to 40 μm and an area of 50 μm² to 1300 μm², and the light-transmitting portion being difficult to visually recognize, thus minimizing the visibility of the bright line prevention region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the width of the frame is reduced to increase the display screen area, then the display screen area is increased, but the bright line prevention region becomes visually recognizable and reduces visibility
Solution Approach 1:
The luminance equalization region is divided into multiple dots arranged in a matrix pattern, with each dot containing colored particles distributed within a light-transmitting resin layer. This segmentation allows the bright line prevention function to be distributed across many small elements rather than a single continuous region, reducing visual recognizability while maintaining effectiveness.
Solution Approach 2:
The dots are arranged with different densities in different regions: a first density in the end region and a second density in the visible region, where the second density is lower than the first. This local quality variation ensures effective light absorption near the light source while minimizing visual impact in the visible display area.
Solution Approach 3:
Colored particles are used within the dots to absorb light with extremely high intensity caused by light leaking from the light source or hot spots. The colored portions provide the necessary light absorption function while the light-transmitting resin surrounding them reduces visual recognizability.
2Object-affected harmful factors
If a frame-shaped bright line prevention region is provided at peripheral sides to absorb light leakage and hot spots, then light leakage and hot spots are reduced, but the bright line prevention region appears on the display screen due to expansion and contraction and dimensional tolerances
Solution Approach 1:
The continuous frame-shaped bright line prevention region is segmented into discrete dots arranged in a matrix. This segmentation provides tolerance to dimensional variations and positional inaccuracies, as the distributed dot pattern maintains its light absorption function even when individual dot positions vary due to manufacturing tolerances.
Solution Approach 2:
The dot density parameter is varied across different regions: a higher first density in the end region and a lower second density in the visible region. This parameter change allows the system to maintain effective light absorption near the light source while reducing the visual impact in the visible display area, compensating for variations in assembly precision.
3Loss of information
If the bright line prevention region is made smaller to reduce visibility, then visibility is maintained, but the ability to absorb light leakage and hot spots is reduced
Solution Approach 1:
Different regions of the optical sheet are assigned different dot densities according to their functional requirements: the end region (near the light source) uses a higher first density to maximize light absorption, while the visible region uses a lower second density to minimize visual recognizability. This local quality differentiation resolves the contradiction between absorption effectiveness and visual clarity.
Solution Approach 2:
The use of colored particles within the dots provides high light absorption capability in a compact form. The colored portions absorb light with extremely high intensity from light leakage and hot spots, while the surrounding light-transmitting resin reduces the overall visual impact, allowing effective absorption without requiring large visible regions.
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 solution effectively prevents a reduction in visibility while reducing the influence of light leakage and hot spots, allowing for a smaller frame size without compromising the display quality, thereby increasing the visible screen area.
Implementation Method 1
the colored portion has a width of 10 μm to 40 μm and an area of 50 μm² to 1300 μm², and the light-transmitting portion is difficult to visually recognize, thus minimizing the visibility of the bright line prevention region
Data Source
AI summary
A luminance equalization region is formed on one surface of an optical sheet incorporated into a liquid crystal display device to equalize luminance of a visible region of the liquid crystal display device. The luminance equalization region is in at least the visible region in a state in which the optical sheet is incorporated into the liquid crystal display device. The luminance equalization region in the visible region has a colored portion and a light-transmitting portion that surrounds the colored portion. The distance from an end of a display surface of the liquid crystal display device to an end of the visible region is 10 mm or less.