LCD Electrode Layout to Prevent Subpixel Light Leakage

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Solution Overview

Problem

Existing liquid crystal display devices face challenges in achieving high definition, high aperture ratio, high contrast ratio, low voltage operation, low power consumption, and high reliability, particularly due to issues with horizontal electric fields causing alignment defects and light leakage between subpixels.

Innovation Solution

The display device incorporates a structure where the first common electrode overlaps with the second common electrode only between adjacent subpixels of different colors, with openings in the display region, and a liquid crystal layer thickness optimized to prevent horizontal electric fields, while using an oxide semiconductor transistor for improved performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional liquid crystal display device is used, then it can display images, but horizontal electric fields cause alignment defects and light leakage between subpixels

Engineering Contradiction:

Improvedisplay qualityVSAvoidlight leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and eliminates the harmful horizontal electric field component by designing the common electrode to overlap with the pixel electrode only in non-display regions. This configuration removes the source of horizontal electric fields that cause alignment defects and light leakage, while maintaining the necessary vertical electric field for liquid crystal operation.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The common electrode is segmented into multiple regions with different functions: a first common electrode in the display region that overlaps with the pixel electrode, and a second common electrode in the non-display region that extends beyond the pixel electrode. This segmentation allows the device to maintain vertical electric fields for display while avoiding horizontal electric fields at subpixel boundaries.

Inventive Principle:

Principle #1Segmentation

2Illumination intensity

If the aperture ratio is increased, then more light can pass through, but the risk of light leakage between subpixels increases

Engineering Contradiction:

Improveaperture ratioVSAvoidlight leakage

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the horizontal electric field component that causes light leakage by configuring the common electrode to extend into non-display regions. This allows the display region to have a high aperture ratio without the accompanying problem of light leakage between subpixels, as the harmful electric field is extracted from the display region and confined to non-display regions.

Inventive Principle:

Principle #2Taking out (Extraction)

3Power

If the display device operates at higher voltage, then it can drive the liquid crystal more effectively, but power consumption increases

Engineering Contradiction:

Improvedriving voltageVSAvoidpower consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The patent applies different electrode configurations to different regions: in the display region, the first common electrode overlaps with the pixel electrode to provide effective vertical electric fields for liquid crystal switching; in the non-display region, the second common electrode extends beyond the pixel electrode to prevent horizontal electric fields. This local differentiation allows effective display operation at lower voltages without the power penalty of higher voltage operation.

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 design enhances display quality by reducing light leakage, increasing contrast ratio, and lowering power consumption while maintaining a high aperture ratio and allowing low-voltage operation, thus providing a highly reliable liquid crystal display.

Implementation Method 1

a liquid crystal layer. The pixel electrode and the first common electrode are positioned between the liquid crystal layer and one of the substrates

Methodology Applied

Scientific EffectLiquid crystal electrophoresis: Electrophoresis

Implementation Method 2

techniques in which a metal oxide that exhibits semiconductor characteristics is used instead of a silicon semiconductor in a transistor have attracted attention

Methodology Applied

Scientific EffectSemiconductor field effect:

Data Source

PatentUS20260010041A1Display device, module, and electronic device

Publication Date: 2026.01.08 SEMICON ENERGY LAB CO LTD

AI summary

A high-definition liquid crystal display device is provided. A liquid crystal display device with a high aperture ratio is provided. A liquid crystal display device with a high contrast ratio and display quality is provided. A liquid crystal display device capable of being driven at a low voltage is provided. The display device includes, between a pair of substrates, a pixel electrode, a first common electrode, a second common electrode, and a liquid crystal layer. The pixel electrode and the first common electrode are positioned between the liquid crystal layer and one of the substrates. The second common electrode is positioned between the liquid crystal layer and the other substrate. The same potential is supplied to the first common electrode and the second common electrode. The first common electrode includes a portion overlapping with the second common electrode between the display regions of two adjacent subpixels that exhibit different colors. At least one of the pixel electrode and the first common electrode includes a portion that does not overlap with the second common electrode in the display region of the subpixel.