Common Electrode Overlapping Capacitor and Pixel Electrodes

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Solution Overview

Problem

Display devices with small-sized sub-pixels face issues of current leakage and insufficient storage capacitance, making it difficult to reduce frame rate and increase usage time, especially in high-resolution displays.

Innovation Solution

The display device incorporates a common electrode that overlaps with capacitor and pixel electrodes, using a transparent conductive material to reduce voltage differences between sub-drains and sub-sources through main-capacitors, maintaining pixel voltage even when the driving elements are turned off, thereby reducing energy loss and improving current leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the size of sub-pixels is reduced to increase display resolution, then the resolution is improved, but the storage capacitance becomes insufficient causing current leakage and making it difficult to reduce frame rate

Engineering Contradiction:

Improvedisplay resolutionVSAvoidcurrent leakage

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a dual-capacitance structure with main-capacitor and sub-capacitor arranged in parallel, effectively increasing the storage capacitance in the vertical dimension without expanding the horizontal sub-pixel area. This dimensional approach allows maintaining high resolution while sufficient capacitance for voltage holding.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The sub-capacitor is nested within the structure of the main-capacitor, with the common electrode serving as a shared element between both capacitors. This nested arrangement maximizes the use of available space within the sub-pixel, increasing total capacitance without proportionally increasing area.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Use of energy by moving object

If the frame rate is reduced to decrease power consumption and increase usage time, then energy efficiency is improved, but insufficient storage capacitance prevents voltage maintenance

Engineering Contradiction:

Improvepower consumptionVSAvoidvoltage maintenance capability

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The dual-capacitance structure is pre-configured to store sufficient charge before the driving elements turn off. The main-capacitor and sub-capacitor work together to maintain voltage during the off-period, enabling reduced frame rates without compromising display performance or voltage stability.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If a dual-capacitance structure with common electrode is introduced to improve voltage holding, then storage capacitance is increased, but device structure becomes more complex

Engineering Contradiction:

Improvevoltage holding capabilityVSAvoidelectrode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The common electrode serves multiple functions simultaneously: it acts as one electrode for the main-capacitor, another electrode for the sub-capacitor, and provides a shared reference potential. This multi-functionality increases capacitance while minimizing the number of additional electrode structures required.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances the sustainability of pixel voltages, reduces energy loss, and extends the usage time of high-resolution display devices by minimizing current leakage and frame rate reduction.

Implementation Method 1

The common electrode and the first capacitor electrode have a first main-capacitor therebetween

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

A material of the first capacitor electrode, the first pixel electrode and the common electrode includes a transparent conductive material

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS11264413B2Display device having common electrode overlapping capacitor electrode and pixel electrode

Publication Date: 2022.03.01 AU OPTRONICS CORP

AI summary

A display device includes a substrate, a first data line, a scan line, a first sub-pixel, a passivation layer, and a common electrode. The first sub-pixel includes a first main-driving element, a first sub-driving element, a first capacitor electrode, and a first pixel electrode. The first main-driving element includes a first main-gate, a first main-channel layer, a first main-source, and a first main-drain. The first sub-driving element includes a first sub-gate, a first sub-channel layer, a first sub-source, and a first sub-drain. The first capacitor electrode is electrically connected with the first main-drain and the first sub-source. The first pixel electrode is electrically connected with the first sub-drain. The common electrode and the first capacitor electrode have a first main capacitor therebetween. The common electrode and the first pixel electrode have a first sub capacitor therebetween.