EL Display Panel Coupling Capacitor Voltage Reset

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Solution Overview

Problem

Existing organic EL display technologies face challenges in achieving uniform display due to variations in transistor characteristics, leading to increased power consumption when high-frequency data line driving is required to compensate for threshold voltage irregularities and mobility variations.

Innovation Solution

The method involves using a coupling capacitor to reset and set the voltage independently of transistor characteristics, reducing the voltage amplitude difference between high and low states, thereby reducing power consumption by allowing for lower voltage amplitudes on data lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If transistors are driven with constant voltage in digital driving method to compensate for threshold voltage variations, then display uniformity is improved, but power consumption increases due to high-frequency data line charging and discharging

Engineering Contradiction:
Improvedisplay uniformityVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-charging the data line to an intermediate potential before data writing. This preliminary charging reduces the voltage swing required during subsequent data writing operations, thereby reducing power consumption while maintaining the ability to compensate for transistor threshold voltage variations and achieve display uniformity.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If high-frequency driving is used to access pixels multiple times per frame period, then display uniformity is improved through multiple data line updates, but power consumption increases due to frequent charging and discharging of data lines

Engineering Contradiction:
Improvedisplay uniformityVSAvoidpower consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by stationary object

Solution Approach 1:

The patent applies preliminary action by pre-charging the data line to an intermediate potential before data writing. This preliminary charging reduces the voltage swing required during subsequent data writing operations, thereby reducing power consumption while maintaining the ability to compensate for transistor threshold voltage variations and achieve display uniformity.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If large voltage amplitude is applied to data lines to ensure sufficient signal amplitude for reliable transistor switching, then reliability is improved, but power consumption increases

Engineering Contradiction:
Improvetransistor switching reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by pre-charging the data line to an intermediate potential before data writing. This preliminary charging reduces the voltage swing required during subsequent data writing operations, thereby reducing power consumption while maintaining the ability to compensate for transistor threshold voltage variations and achieve display uniformity.

Inventive Principle:
Principle #10Preliminary 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 approach enables reduced power consumption while maintaining display uniformity by allowing for lower voltage amplitudes and eliminating the need for frequent charging and discharging of data lines, achieving efficient power management and improved display performance.

Implementation Method 1

a coupling capacitor 6 having the other terminal thereof connected to a data line 7

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2272059B1Display panel
Publication Date: 2019.06.12 GLOBAL OLED TECHNOLOGY LLC
  • EP2272059B1 patent drawingFigure 1
  • EP2272059B1 patent drawingFigure 2
  • EP2272059B1 patent drawingFigure 3

AI summary

An EL light-emitting element is driven digitally to reduce power consumption using a pixel having three transistors and two capacitors. A reset transistor for diode connection writes the threshold voltage of the drive transistor onto a coupling capacitor. The data voltage plus threshold voltage is then written onto the gate of the drive transistor. This reduces the amplitude of the data voltage required, further reducing power consumption.