OLED Subpixel Gate Line Structure for Aperture Ratio and Brightness Uniformity

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Solution Overview

Problem

Existing organic light emitting display devices face challenges in maintaining uniform brightness due to characteristic variations in circuit elements within subpixels, leading to reduced picture quality. Additionally, current technologies require multiple gate lines per subpixel line, which deteriorates the aperture ratio.

Innovation Solution

The proposed solution involves a subpixel structure and gate line connection structure that allows for individual control of two types of scan transistors within each subpixel using only one gate line per subpixel line. This enables sensing and compensation for degradation of organic light emitting diodes and driving transistors, while maintaining a high aperture ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple gate lines are used per subpixel line to individually control scan transistors, then individual control of transistors is achieved, but the aperture ratio deteriorates

Engineering Contradiction:
Improveindividual control of scan transistorsVSAvoidaperture ratio
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent merges the control of multiple scan transistors (first scan transistor and second scan transistor) into a single gate line structure. The gate electrode of the first scan transistor and the gate electrode of the second scan transistor are connected to the same gate line, allowing both transistors to be controlled through a single signal line, thus avoiding the need for multiple separate gate lines that would reduce the aperture ratio.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs periodic control of the scan transistors through timing-based signal switching. The first scan transistor is turned on during a first period to transfer data voltage, while the second scan transistor is turned on during a second period for sensing operations. This periodic action allows individual control of each transistor through a single shared gate line without requiring simultaneous separate control lines.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If two transistors are used to separately control voltage states of gate node and source node, then degradation sensing is enabled, but the device complexity increases

Engineering Contradiction:
Improvedegradation sensing capabilityVSAvoidtransistor count and control structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the single gate line serve multiple functions: it controls both the first scan transistor for data transfer and the second scan transistor for sensing operations. This multi-functional design enables degradation sensing capability while avoiding the complexity of separate dedicated control lines for each transistor function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent segments the control timing into distinct periods: a first period for data transfer operation and a second period for sensing operation. By dividing the control timeline into separate segments, the system can individually control different transistor functions through a single shared gate line, reducing structural complexity while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

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 allows for increased aperture ratio and effective image driving and sensing, thereby improving picture quality by maintaining uniform brightness across subpixels. It also enables the sensing of organic light emitting diode degradation within each subpixel through a single gate line, enhancing the overall performance of the organic light emitting display device.

Implementation Method 1

an organic light emitting diode which emits light by itself

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3188177B1Organic light emitting display panel, organic light emitting display device, and method of driving organic light emitting display device
Publication Date: 2025.04.23 LG DISPLAY CO LTD
  • EP3188177B1 patent drawingFigure 1
  • EP3188177B1 patent drawingFigure 2
  • EP3188177B1 patent drawingFigure 3

AI summary

Disclosed are an organic light emitting display panel, an organic light emitting display device, and a method of driving the organic light emitting display device. The organic light emitting display panel, the organic light emitting display device, and the method of driving the organic light emitting display device having a subpixel structure and a gate line connection structure in which two types of scan transistors within each subpixel can be individually turned on and off and image driving and various types of sensing driving can be performed while the aperture ratio increases through the individual on and off of the scan transistors.