Gate Driver Segmentation for OLED Luminance Uniformity
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Solution Overview
Problem
In organic light emitting display devices, luminance differences are noticeable when using the split drive mode due to non-uniform characteristics of drive transistors across different areas of the display panel, especially when transitioning from split drive to full drive mode.
Innovation Solution
The implementation of a gate driver with multiple stage groups and initiation signals (first, second, and third stage initiation signals) that control the activation of gate signals and light emission across different areas of the display panel, ensuring uniformity in data voltage charging and light emission control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If split drive mode is used to display image on only part of display area, then power consumption is reduced and driving efficiency is improved, but luminance difference becomes noticeable between different areas due to non-uniform drive transistor characteristics
Solution Approach 1:
The gate driver is divided into multiple stage groups (first stage group, second stage group, third stage group) that can be independently controlled through separate initiation signals. This segmentation allows different areas of the display panel to be driven independently, enabling the system to address luminance non-uniformity in specific regions while maintaining overall driving efficiency in split drive mode.
Solution Approach 2:
Different stage groups are assigned to control different areas of the display panel (first area, second area, third area). By locally controlling each area with dedicated stage groups and initiation signals, the system can compensate for area-specific luminance differences caused by non-uniform transistor characteristics, ensuring uniform display quality across the entire panel even when using split drive mode.
2Use of energy by stationary object
If split drive mode is used, then power consumption is reduced, but luminance difference between displayed and non-displayed areas becomes visually recognizable
Solution Approach 1:
The gate driver is segmented into multiple independently controllable stage groups, each receiving initiation signals for specific areas. This allows the system to maintain uniform luminance characteristics across all areas including those not currently displaying images, while still achieving power savings through selective area driving.
Solution Approach 2:
The initiation signals are designed to pre-charge data voltages and prepare transistor characteristics in advance for all areas before actual image display. This preliminary action ensures that even areas not displaying images maintain uniform transistor characteristics, preventing visible luminance differences when transitioning between split drive mode and full drive mode.
3Illumination intensity
If multiple stage groups with separate initiation signals are implemented, then luminance uniformity is improved across different areas, but device complexity increases
Solution Approach 1:
The gate driver is divided into multiple stage groups that can be independently controlled. While this increases structural complexity, each stage group follows the same operational pattern, allowing for modular design and simplified manufacturing. The segmentation enables precise control over luminance uniformity in each display area.
Solution Approach 2:
Multiple stage groups are designed with identical functional characteristics and can be universally applied to different display areas. Each stage group can serve multiple purposes: driving active display areas, maintaining inactive areas, and preparing for mode transitions. This universality reduces the need for area-specific custom circuits, balancing complexity with functionality.
Data Source
AI summary
An organic light emitting display device including: a display panel including a plurality of pixels; a gate driver including a plurality of stage groups each including at least one stage providing a gate signal to the pixels; a timing controller providing a first stage initiation signal or a second stage initiation signal to the at least one stage; and a first stage initiation line and a second stage initiation line transmitting the first stage initiation signal and the second stage initiation signal from the timing controller to the gate driver.