Pixel Structure Repairable Capacitor Dielectric Configuration

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Solution Overview

Problem

Conventional laser repairing technologies for TFT-LCD pixel structures often result in differences in feed through voltage after repair, leading to slight bright dots due to abnormal storage capacitances.

Innovation Solution

A pixel structure with specific dielectric layer configurations and a repairing method that involves isolating and welding contact regions to maintain consistent feed through voltage, using a first and second dielectric layer with controlled dielectric constants and thicknesses to match the normal pixel structure's capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional laser repairing technologies are used to repair abnormal pixel structures, then the storage capacitance can be restored, but the feed through voltage becomes different from normal pixel structures, causing slight bright dots

Engineering Contradiction:

Improvestorage capacitance restorationVSAvoidfeed through voltage consistency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by carefully controlling the dielectric constant and thickness of the dielectric layer during repair. By adjusting these parameters, the storage capacitance of the repaired pixel structure is matched to the normal pixel structure, thereby restoring the feed through voltage to its original value and eliminating the bright dot defect.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by using a dielectric layer with specific local properties (controlled dielectric constant and thickness) only in the repaired region. This localized approach ensures that the repair affects only the defective pixel structure while maintaining the original characteristics of surrounding normal pixel structures.

Inventive Principle:

Principle #3Local quality

2Ease of repair

If the storage capacitance is changed during repair, then the dot defect can be fixed, but the feed through voltage difference causes image quality degradation

Engineering Contradiction:

Improvedot defect fixationVSAvoidimage brightness uniformity

Core Design Contradiction:

Ease of repairVSIllumination intensity

Solution Approach 1:

The patent uses parameter changes to restore the storage capacitance to its original value by controlling the dielectric layer properties. This ensures that the feed through voltage remains consistent between repaired and normal pixel structures, preventing brightness non-uniformity in the displayed image.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful effect of capacitance change during repair into a beneficial outcome by precisely controlling the dielectric layer parameters. Instead of causing brightness defects, the controlled parameter changes restore the capacitance while maintaining voltage consistency, thereby eliminating the bright dot defect.

Inventive Principle:

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

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

The method effectively avoids slight bright dots by ensuring the feed through voltage of repaired pixel structures remains insignificantly different from normal pixel structures, enhancing repair efficiency and image quality.

Implementation Method 1

the dielectric constant of the first dielectric layer is ∈1, the thickness of the first dielectric layer is d1; the dielectric constant of the second dielectric layer is ∈2, the thickness of the second dielectric layer is d2, and 0.51·d2·A)/(∈2·d1·B)1·d2·A)/(∈2·d1·B) is between 0.7 and 1.3

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

the first dielectric layer is at least disposed between the bottom electrode and the upper electrodes, and the second dielectric layer is at least disposed between the upper electrodes and the pixel electrode

Methodology Applied

Scientific EffectDielectric: Dielectric

Data Source

PatentUS8169561B2Pixel structures with repairable capacitor structures

Publication Date: 2012.05.01 AU OPTRONICS CORP

AI summary

A pixel structure including an active device, a pixel electrode connected with the active device, a bottom electrode disposed under the pixel electrode, upper electrodes disposed between the pixel electrode and the bottom electrode and connected with the pixel electrode, a first dielectric layer disposed between the bottom electrode and the upper electrodes and a second dielectric layer disposed between the upper electrodes and the pixel electrode is provided. The total area of the upper electrodes overlapping with the bottom electrode is A, and the overlapping portion of the pixel electrode and each upper electrode includes a contact region and a reserved region having total area B. The dielectric constant and thickness of the first dielectric layer is ∈1 and d1; and for second dielectric layer ∈2 and d2, wherein 0.5<(∈1·d2·A)/(∈2·d1·B)<1.5.