OLED Shift Register Circuit for Bezel Area Reduction

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Solution Overview

Problem

Existing OLED displays face challenges in reducing the size of the bezel area due to the complexity of the Gate In Panel (GIP) circuit, which increases the size of the scan driving unit and consequently the bezel size.

Innovation Solution

The implementation of a shift register that applies first scan signals simultaneously to pixels along two adjacent horizontal lines and generates emission control signals for fourth and fifth transistors, allowing for a reduced bezel area by simplifying the circuit configuration and sharing scan and emission control signals across adjacent pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional Gate In Panel (GIP) circuit is used to generate scan signals and emission control signals, then the display function is achieved, but the bezel area increases due to the complex circuit configuration

Engineering Contradiction:
Improvebezel areaVSAvoidcircuit complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the functions of generating first scan signals, second scan signals, and emission control signals into a single integrated shift register unit. This consolidation eliminates the need for separate GIP circuits for each signal type, directly reducing the bezel area while maintaining the necessary display functionality through shared signal generation and distribution mechanisms

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shift register is designed to perform multiple functions: generating first scan signals for initialization, second scan signals for data sampling, and emission control signals for light output timing. This multi-functional approach replaces multiple specialized circuits with a single versatile unit, reducing overall circuit complexity and bezel space requirements

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

2Area of stationary object

If separate scan drivers and emission control drivers are used to drive pixels, then precise control is achieved, but the dead space in the display increases

Engineering Contradiction:
Improvedead spaceVSAvoidsignal control precision
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The patent combines separate scan drivers and emission control drivers into a unified shift register architecture that sequentially generates different signal types. This merging eliminates the physical space required for multiple independent driver circuits while maintaining precise control through time-multiplexed signal generation and distribution to respective pixel components

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If the shift register applies first scan signals simultaneously to two adjacent horizontal lines, then the scanning speed is improved, but the signal distribution complexity increases

Engineering Contradiction:
Improvescanning speedVSAvoidsignal distribution complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent extends the signal distribution from a single horizontal line to two adjacent horizontal lines simultaneously by adding vertical dimensionality to the scan signal routing. This allows parallel processing of multiple pixel rows, improving scanning speed while the systematic extension of the shift register architecture manages the increased distribution complexity through organized signal paths

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3151232B1Organic light emitting diode (OLED) display
Publication Date: 2020.05.06 LG DISPLAY CO LTD
  • EP3151232B1 patent drawingFigure 1
  • EP3151232B1 patent drawingFigure 2
  • EP3151232B1 patent drawingFigure 3

AI summary

Disclosed is an Organic Light Emitting Diode (OLED) display including pixels (P) and a shift register for driving transistors (DT) arranged in the pixels (P). The shift register applies first scan signals (Scan1) at the same time to pixels (P) arranged along two adjacent horizontal lines. A second scan signal stage applies second scan signals (Scan2) sequentially to pixels (P) arranged along two adjacent horizontal lines. An emission control signal stage generates emission control signals which are to be applied to fourth and fifth transistors (T4, T5).