Bent Data Lines and Auxiliary Capacitor Structure for LCD Aperture Ratio
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Solution Overview
Problem
Liquid crystal displays (LCDs) face issues with variations in coupling capacitance due to misalignment between pixel electrodes and data lines, leading to uneven image quality and reduced aperture ratio, which existing solutions like S-shaped data lines and opaque capacitor electrodes fail to adequately address.
Innovation Solution
The design incorporates bent data lines with auxiliary capacitor lines and a light-shielding matrix, where the extension portion of the auxiliary capacitor lines is covered by the matrix, providing additional storage capacitance without reducing the transparent area, and connection lines are strategically placed to increase the transparent area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If pixel electrodes overlap data lines to increase aperture ratio, then aperture ratio is improved, but coupling capacitance variations occur due to misalignment
Solution Approach 1:
The data line is designed with an S-shape configuration instead of a straight line. This asymmetric design creates symmetrical coupling capacitance regions (Csd1 and Csd2) on both sides of the pixel electrode, making the total coupling capacitance independent of alignment precision between the pixel electrode and data line.
2Reliability
If black matrix is widened to cover S-shaped data lines for assembly precision, then assembly precision is improved, but aperture ratio is reduced
Solution Approach 1:
The light-shielding matrix is designed with different widths in different regions. It has a first width in the first region and a second width (narrower than the first width) in the second region where the extension portion of the auxiliary capacitor line is located. This allows the extension portion to be covered for light leakage prevention while minimizing the impact on aperture ratio.
3Reliability
If opaque capacitor electrode is used for storage capacitor, then storage capacitance is provided, but aperture ratio is reduced
Solution Approach 1:
The auxiliary capacitor line extends in a direction perpendicular to the scanning line, creating an extension portion that can be covered by the light-shielding matrix. This dimensional arrangement allows the capacitor structure to provide storage capacitance while the covered extension portion does not reduce the effective transparent display area.
Data Source
AI summary
Disclosed is a liquid crystal display mainly including a plurality of pixel electrodes, scanning lines, signal lines and auxiliary capacitor lines on a thin film transistor (TFT) substrate, and a light-shielding matrix on a color filter (CF). Each signal line is bent between two adjacent scanning lines, so as to form a first portion, a second portion and two connection portions connecting the first and second portions. The first and the second portions are respectively covered with opposite side portions of two adjacent pixel electrodes. Each auxiliary capacitor line has a main body parallel to the scanning line and an extension portion extending outwardly from the main body. The extension portion of each auxiliary capacitor line is located between the two connection portions of the data line.