Asymmetric Sub-Pixel Circuit Layout for Liquid Crystal Display Transmittance
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Solution Overview
Problem
In very large liquid-crystal display devices with a color-filter-on TFT (COT) structure, the black strip (BS) region at the boundary between sub-pixels increases, reducing the aperture ratio and transmittance, hindering high resolution and meeting customer needs.
Innovation Solution
The design involves disposing two thin-film transistors together in a circuit area of one sub-pixel next to another in a horizontal direction, creating an asymmetric structure that reduces the BS region by expanding the aperture area of adjacent sub-pixels, thereby increasing transmittance and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a color filter is formed on the lower substrate with switching elements (COT structure), then the aperture ratio is improved by reducing margin during substrate attachment, but the black strip region increases at sub-pixel boundaries reducing transmittance
Solution Approach 1:
The patent applies asymmetry by designing adjacent sub-pixels with different configurations. Specifically, in a row of sub-pixels, odd-numbered sub-pixels have circuit areas positioned differently from even-numbered sub-pixels. This asymmetric arrangement allows the black strip regions of adjacent sub-pixels to offset each other, reducing the overall visible black strip width and improving light transmittance while maintaining the COT structure's aperture ratio benefits.
2Reliability
If the black strip region is increased to prevent light leakage at sub-pixel boundaries, then light leakage is prevented, but the aperture ratio is reduced
Solution Approach 1:
The asymmetric design of adjacent sub-pixels causes their black strip regions to be positioned differently. This offset arrangement allows the black strips of neighboring sub-pixels to compensate for each other, maintaining effective light leakage prevention while minimizing the overall black strip visibility and preserving aperture ratio.
Solution Approach 2:
The patent implements local quality by allowing different sub-pixels to have different circuit area positions and black strip configurations. Each sub-pixel is optimized locally with its circuit area positioned to minimize its own black strip impact, while the collective asymmetric arrangement of all sub-pixels achieves global optimization for both light leakage prevention and aperture ratio.
3Area of stationary object
If two thin-film transistors are disposed together in one sub-pixel circuit area, then the aperture area of adjacent sub-pixels is increased, but the sub-pixel structure becomes asymmetric
Solution Approach 1:
The patent embraces asymmetry as a design feature rather than a defect. By intentionally making adjacent sub-pixels asymmetric in their circuit area positioning, the design achieves the benefit of increased aperture area in each sub-pixel. The overall display maintains visual symmetry through the complementary asymmetric arrangements of neighboring sub-pixels, effectively resolving the contradiction between local asymmetry and global symmetry.
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 enhances the display quality by increasing transmittance by approximately 9% or more and improving the aperture ratio in very large models, addressing the limitations of traditional COT structures.
Implementation Method 1
the liquid crystals are aligned by an electric field applied between the common electrode and the pixel electrode
Implementation Method 2
light is refracted in the direction of the orientation of the molecules of the liquid crystals due to optical anisotropy
Data Source
AI summary
Provided is a liquid-crystal display device. The liquid-crystal display device includes gate lines and data lines disposed on a substrate and overlapping with one another to define sub-pixels, two thin-film transistors disposed together in a circuit area of one of two sub-pixels next to each other in a horizontal direction among the sub-pixels; and common electrodes and pixel electrodes disposed alternately in each of the sub-pixels. The two thin-film transistors are connected to the two sub-pixels, respectively.