LCD Shield Electrode Convex Region Light Leakage
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Solution Overview
Problem
Liquid crystal display (LCD) devices with color filters on array (CFOA) type suffer from light leakage due to non-uniform cell gaps between pixels, leading to reduced contrast ratio and altered black color coordinates, as liquid crystals on boundaries are not affected by electric fields and emit light externally.
Innovation Solution
The implementation of a shield electrode with a convex region and a light blocking layer on the boundaries between pixels, where the third sub color filter forms convex regions and the light blocking layer is positioned to direct residual light leakage into the least visible color, reducing external light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If color filters are formed on the first substrate in CFOA type LCD devices, then color display capability is improved, but light leakage occurs at boundaries between pixels due to non-uniform cell gaps
Solution Approach 1:
A shield electrode is introduced as an intermediary element between the color filters and the liquid crystal layer. This shield electrode receives a common voltage and is disposed substantially parallel to the data line along the boundary between adjacent pixels, preventing light leakage by blocking the path of light that would otherwise escape through the non-uniform cell gaps at pixel boundaries.
2Device complexity
If liquid crystals are disposed on boundaries between pixels without pixel electrodes, then manufacturing complexity is reduced, but liquid crystals sustain initial alignment and are not affected by electric fields, causing light leakage
Solution Approach 1:
The shield electrode serves as a mediator that compensates for the absence of pixel electrodes at boundary regions. By receiving a common voltage and being positioned parallel to the data line, it creates an electric field that controls the liquid crystal orientation at boundaries, preventing light leakage without requiring additional pixel electrode structures.
3Object-generated harmful factors
If convex region is formed by third sub color filter protruding toward second substrate, then light leakage is minimized by tinting residual light into blue color, but manufacturing precision requirements increase
Solution Approach 1:
The convex region is formed specifically in the third sub color filter (blue color filter) at the boundary between pixels, rather than uniformly across all color filters. This localized formation creates a protrusion that tints residual light leakage into blue, the least visible color to human eyes, thereby minimizing perceived light leakage while requiring precision only in specific 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 configuration effectively minimizes light leakage by tinting residual light emitted between pixels into blue, the least visible color, thereby enhancing contrast ratio and maintaining accurate black color coordinates.
Implementation Method 1
The LCD device displays images by applying electric fields to the liquid crystal layer, which changes the orientation of liquid crystal molecules in the liquid crystal layer, which in turn varies the transmittance of light through the liquid crystal layer.
Implementation Method 2
a color filter which includes a first sub color filter, a second sub color filter and a third sub color filter, each of the first, second and third sub color filters including a different color
Data Source
AI summary
A liquid crystal display device includes; a first substrate, a second substrate facing the first substrate and having a common electrode, and a liquid crystal layer, the first substrate including; a plurality of pixels, a thin film transistor, a pixel electrode, a color filter including a first sub color filter, a second sub color filter and a third sub color filter, each sub color filter including a different color, and a shield electrode receiving a common voltage and disposed substantially parallel to the data line along a boundary between adjacent pixels on the color filter, wherein the color filter disposed below the shield electrode comprises a convex region which protrudes toward the second substrate, the plurality of pixels comprise a first pixel having the first sub color filter, a second pixel having the second sub color filter and a third pixel having the third sub color filter, and the third sub color filter forms the convex region.