Pixel Electrode Cell Gap Design for Display Color Shift

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Solution Overview

Problem

Current wide viewing angle liquid crystal display technologies face issues of color shift and insufficient color saturation due to birefringence properties of liquid crystal molecules, which are exacerbated by the need for additional transistors and scan lines, leading to lower process yield rates and aperture ratios.

Innovation Solution

The design features pixel electrodes with the same electric potential but different distances to the common electrode layer, achieved through a varying interlayer configuration, allowing for distinct electric fields and tilt angles without increasing active components, thereby mitigating color shift and enhancing color saturation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If separate pixel electrodes with different voltages are used to mitigate color shift, then color shift is reduced, but the number of thin film transistors and scan lines increases

Engineering Contradiction:
Improvecolor shiftVSAvoidnumber of thin film transistors and scan lines
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating different cell gaps at different locations within the same pixel electrode structure. Specifically, a first cell gap is formed between the pixel electrode and common electrode in a first region, while a second cell gap is formed in a second region, allowing different tilt angles and optical properties in different areas without requiring separate pixel electrodes or additional transistors

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent transitions from controlling different pixels through separate voltage channels (electrical dimension) to controlling different regions through structural geometry (spatial dimension). By varying the cell gap distance in different spatial regions, the patent achieves different liquid crystal tilt angles and optical responses without increasing the number of electrical control lines or transistors

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If additional transistors and scan lines are added to control pixel electrodes, then color shift is mitigated, but process yield rate decreases

Engineering Contradiction:
Improvecolor shiftVSAvoidprocess yield rate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent implements local quality by forming different cell gaps in different regions of the pixel structure. A first cell gap exists between the pixel electrode and common electrode in a first region, while a second cell gap exists in a second region, enabling localized control of liquid crystal orientation and optical properties without adding complex circuitry that would reduce manufacturing yield

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If separate pixel electrodes with different voltages are used, then color saturation is improved, but aperture ratio decreases

Engineering Contradiction:
Improvecolor saturationVSAvoidaperture ratio
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent applies local quality by creating region-specific cell gaps within a single pixel electrode structure. The first cell gap in the first region and the second cell gap in the second region enable different liquid crystal tilt angles and optical responses, improving color saturation and viewing angle characteristics while maintaining a compact structure that preserves aperture ratio

Inventive Principle:
Principle #3Local quality

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 improves the process yield rate and aperture ratio by reducing color shift and enhancing color saturation without additional active components or driving circuits, while maintaining a wide viewing angle effect.

Implementation Method 1

due to the birefringence properties of liquid crystal molecules, there exists a phenomenon where colors seen from a side viewing angle are different from those seen from a direct viewing angle

Methodology Applied
Scientific EffectBirefringence: Birefringence

Implementation Method 2

Through an electric field generated by a voltage difference between the pixel electrode and the common electrode, the display medium layer is driven

Methodology Applied
Scientific EffectElectric field: Electric Field

Data Source

PatentEP3187924B1Display device
Publication Date: 2021.03.31 INNOLUX CORP
  • EP3187924B1 patent drawingFigure 1
  • EP3187924B1 patent drawingFigure 2
  • EP3187924B1 patent drawingFigure 3A~3B

AI summary

The disclosure provides a display device. The pixel electrode of the display device includes a first pixel electrode and a second pixel electrode having the same electric potential. The first interlayer is formed between the first substrate and the first pixel electrode. Adjacent two of the first strip-shaped branches of the first interlayer form a first gap to expose part of the first substrate. The common electrode layer is disposed over the second substrate. The pixel electrode is positioned between the first substrate and the display medium layer. The first pixel electrode extends to cover the first gap. A difference between a maximum distance between the first pixel electrode and the common electrode layer and a maximum distance between the second pixel electrode and the common electrode layer is 0.1 µm to 0.4 µm.