OLED Emission-Control Circuit for Overheating Prevention

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Solution Overview

Problem

Organic Light Emitting Diode (OLED) displays face a reduction in life span due to overheating from prolonged high-intensity light emission, leading to instability and uniformity issues in image display.

Innovation Solution

An emission-control circuit is introduced, comprising a light sensor, multiple thin-film transistors (TFTs), and capacitors, which detects light intensity and generates an emission control signal to temporarily turn off the OLED during high-intensity periods, preventing overheating and extending the OLED's life span.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If OLED continuously emits light at high intensity, then display brightness is maintained, but OLED life span is reduced due to overheating

Engineering Contradiction:
Improvedisplay brightnessVSAvoidOLED life span
Core Design Contradiction:
Illumination intensityVSDuration of action of stationary object

Solution Approach 1:

The emission control circuit implements periodic action by intermittently turning off the OLED during high-intensity light emission periods. The circuit detects when the OLED has been emitting light continuously and generates control signals to temporarily stop emission, then resumes it after a predetermined period. This periodic on-off cycling prevents cumulative overheating while maintaining overall display brightness, thereby extending OLED life span without sacrificing display performance.

Inventive Principle:
Principle #19Periodic action

2Duration of action of stationary object

If emission control circuit intermittently turns off OLED, then OLED life span is extended, but display continuity is interrupted

Engineering Contradiction:
ImproveOLED life spanVSAvoiddisplay continuity
Core Design Contradiction:
Duration of action of stationary objectVSDuration of action of moving object

Solution Approach 1:

The emission control circuit applies partial action by selectively interrupting OLED emission only during periods of continuous high-intensity operation, rather than continuously or randomly. The circuit uses a detection mechanism to identify when interruption is necessary (after predetermined continuous emission periods) and applies the control signal only in those specific cases. This selective approach minimizes disruptions to display continuity while still providing protective interruptions to extend OLED life span.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If light sensor and control circuit are added, then OLED overheating is prevented, but device complexity increases

Engineering Contradiction:
Improveoverheating preventionVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The emission control circuit merges multiple functions into a single integrated circuit block. The circuit combines the light emission detection capability, continuous operation timing measurement, and emission control signal generation functions all within one circuit unit that is coupled to the OLED. This merging approach prevents overheating through intelligent control while minimizing the increase in device complexity by consolidating control functions rather than adding separate independent components for each function.

Inventive Principle:
Principle #5Merging (Combining)

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 emission-control circuit effectively prolongs the OLED's life span by intermittently turning off the OLED during high-intensity light emission, maintaining stability and uniformity in image display.

Implementation Method 1

a light sensor PN configured to detect an intensity of emitted light of the OLED

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP3488436B1Emission-control circuit, display apparatus having the same, and driving method thereof
Publication Date: 2024.09.04 BOE TECHNOLOGY GROUP CO LTD
  • EP3488436B1 patent drawingFigure 1~2
  • EP3488436B1 patent drawingFigure 3~4
  • EP3488436B1 patent drawingFigure 5A~5B

AI summary

An emission-control circuit for controlling light emission of an OLED, including a light sensor (PN) configured to detect an intensity of emitted light of the OLED; a first TFT (T1); a second TFT (T2); a third TFT (T3); a fourth TFT (T4); a fifth TFT (T5); a sixth TFT (T6); a first capacitor (C11); and a second capacitor (C12).