Pixel Structure with Segmented Electrodes for Wide Viewing Angles

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Solution Overview

Problem

Conventional liquid crystal display (LCD) pixel structures face challenges in balancing wide viewing angles with high aperture ratios, often resulting in light leakage and disclination phenomena due to alignment issues with liquid crystal molecules, which degrade display contrast and efficiency.

Innovation Solution

A pixel structure design featuring a substrate with specific arrangements of scan lines, data lines, and pixel electrodes, including stripe patterns and branches that control the overlap with scan lines and data lines, along with a storage capacitor structure and color filter placement, to minimize light leakage and disclination by optimizing the overlap ratios and electrode connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If alignment protrusions and alignment slits are disposed on electrodes to achieve wide viewing angle, then liquid crystal molecules can tilt in different angles, but light leakage and disclination phenomena occur due to misalignment, degrading display contrast

Engineering Contradiction:
Improveviewing angleVSAvoidlight leakage
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The pixel electrode is divided into multiple segments (first pixel electrode and second pixel electrode) with different alignment structures. Each segment has alignment protrusions oriented in different directions, enabling different liquid crystal tilt angles in different regions. This segmentation allows the display to achieve wide viewing angles while maintaining proper alignment in each segment to reduce light leakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel electrode are given different local properties through varying alignment protrusion orientations. The first pixel electrode has alignment protrusions oriented in one direction while the second pixel electrode has alignment protrusions oriented in another direction. This local differentiation enables each region to optimize its liquid crystal alignment for its specific function, reducing disclination and light leakage while achieving wide viewing angles.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If light shielding layer is disposed to reduce light leakage and disclination, then display contrast improves, but aperture ratio is limited

Engineering Contradiction:
Improvelight leakageVSAvoidaperture ratio
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The invention extracts and removes the light shielding layer from the display structure. Instead of using a separate light shielding layer to prevent light leakage, the patent achieves light leakage prevention through proper alignment of liquid crystal molecules via alignment protrusions and controlled electrode overlapping. This extraction eliminates the need for light shielding layers, thereby increasing the aperture ratio while still preventing light leakage through molecular alignment control.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention converts the potential harmful effect of electrode overlapping (which could cause alignment issues) into a beneficial feature. By carefully designing the overlapping region between first and second pixel electrodes and using alignment protrusions to guide liquid crystal orientation in these overlapping areas, the patent transforms what could be a source of light leakage into a means of achieving wide viewing angles without requiring light shielding layers.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Stability of the object's composition

If pixel electrode overlaps with scan line and data line to control alignment, then liquid crystal orientation is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveliquid crystal orientationVSAvoidoverlap ratio control
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The invention specifies particular parameter ranges for the overlapping regions to optimize both alignment control and manufacturing feasibility. The first overlapping width is set to 10-50 micrometers and the second overlapping width to 5-20 micrometers. These parameter specifications provide a balanced design that ensures sufficient overlap for proper liquid crystal alignment while remaining achievable with standard manufacturing tolerances, thus reducing the stringency of precision requirements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2333606B1Pixel structure
Publication Date: 2016.04.06 AU OPTRONICS CORP
  • EP2333606B1 patent drawingFigure 1
  • EP2333606B1 patent drawingFigure 2A~2B
  • EP2333606B1 patent drawingFigure 3

AI summary

A pixel structure including a substrate, a scan line, a first data line and a first pixel unit is provided. The scan line and the first data line are disposed on the substrate. The first pixel unit includes a first active device and a first pixel electrode. The first active device is electrically connected to the scan line and the first data line. The first pixel electrode electrically connected to the first active device has a first stripe pattern and a plurality of first branches. One side of the first stripe pattern is connected to the first branches extended toward the scan line, and the other side of the first stripe pattern is overlapped with the scan line. The overlapped width of the first stripe pattern with the scan line is substantially equal to 40% to 90% of the width of the first stripe pattern.