QLED Reverse Driving Signal Suppresses Charge Accumulation

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Solution Overview

Problem

The long-term accumulation of electric charges at the interface of quantum dot light-emitting diodes (QLEDs) in video display panels leads to reduced luminous intensity and shortened lifetime, affecting the brightness and longevity of the display.

Innovation Solution

A preconfigured reverse driving method is applied in the video display process, where a reverse driving signal is added before the forward driving signal to suppress electric charge accumulation, with the intensity and waveform of the reverse signal proportional to the forward signal, and applied even when pixels are not illuminated, to alter the defect potential well and reduce charge density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If forward driving signal is continuously applied to drive video display content, then the luminous intensity and brightness are maintained, but electric charges accumulate at the interface between layers, reducing lifetime and affecting display quality

Engineering Contradiction:
Improveluminous intensityVSAvoidlifetime
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies periodic reverse driving signals at different frequencies (first frequency for charge suppression, second frequency for water resonance) to the quantum dot light-emitting diode. This periodic action creates time-varying electric fields that prevent charge accumulation while maintaining luminous output, resolving the contradiction between sustained brightness and device lifetime

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes the electrical parameters by switching between forward driving signals and reverse driving signals with different frequencies and polarities. By dynamically adjusting the driving signal parameters (frequency, polarity, amplitude), the system maintains optimal luminous intensity while preventing charge accumulation that would otherwise reduce lifetime

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If forward driving signal is applied to maintain video display brightness, then the display quality is maintained, but electric charges are confined at energy level interfaces, shortening device lifetime

Engineering Contradiction:
ImprovebrightnessVSAvoiddevice lifetime
Core Design Contradiction:
Illumination intensityVSDuration of action of stationary object

Solution Approach 1:

The patent employs periodic reverse driving signals with specific frequencies to create oscillating electric fields that prevent charge confinement at interfaces. The first frequency targets charge suppression while the second frequency (water resonance frequency) enhances the effect, thereby extending device lifetime without compromising brightness

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent converts the harmful effect of applied electric fields (which cause charge accumulation) into a beneficial effect by using reverse polarity signals. The same electric field mechanism that causes charge confinement is inverted to create charge suppression, transforming the harmful forward driving into beneficial reverse driving that extends lifetime while maintaining display quality

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

3Reliability

If reverse driving signal is applied to suppress charge accumulation, then the lifetime is extended, but additional signal processing and timing control are required

Engineering Contradiction:
ImprovelifetimeVSAvoidsignal control complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses periodic reverse driving signals with predetermined frequencies that can be implemented through standard display timing controllers. The periodic nature allows synchronization with existing display refresh cycles, minimizing additional control complexity while achieving charge suppression and lifetime extension

Inventive Principle:
Principle #19Periodic action

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 method effectively reduces electric charge confinement, enhancing the brightness and extending the lifetime of the video display panel by eliminating charge accumulation and altering the potential well barrier.

Implementation Method 1

adding a reverse driving signal before each forward driving signal for driving the display content of the plurality of frames, to suppress accumulation of electric charges on the pixels in the video display panel in advance

Methodology Applied
Scientific EffectElectric Field: Electric Field

Implementation Method 2

the reverse driving signal changes the barrier of the defect potential well, eliminates confinement and accumulation of the electric charges in the potential well

Methodology Applied
Scientific EffectPotential Well: Potential Well

Data Source

PatentEP3633659B1Preset reverse drive method applied in video displaying process
Publication Date: 2023.12.06 TCL TECHNOLOGY GROUP CORPORATION
  • EP3633659B1 patent drawingFigure 1~2
  • EP3633659B1 patent drawingFigure 3~4
  • EP3633659B1 patent drawingFigure 5~6

AI summary

Disclosed in the present disclosure is a preconfigured reverse drive method applied in a video displaying process. The method comprises the steps of: pre-obtaining display content of several frames behind lit pixels in a video by means of content loading; and adding a reverse drive signal before each forward drive signal used for driving the display content of the several frames, to suppress electric charge concentration on pixel in a video display panel in advance. The reverse drive signal changes the potential barrier of the detect potential well, removes electric charges confined and concentrated in the potential well, and reduces the density of confined electric charges. Thus, the video display brightness is improved, and the service life of the video display panel is prolonged.