OLED Pixel Electrode Extension for Low-Frequency Flicker Control
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Solution Overview
Problem
In OLED displays, low frequency driving leads to increased storage capacitor voltage hold times, causing charge leakage and flicker phenomena due to external light or leakage light exposure, which affects luminance and display quality.
Innovation Solution
The OLED display incorporates a first electrode extension part that blocks target transistors from light, including initialization and compensation transistors, to minimize charge leakage and flicker, while maintaining a low power consumption mode with extended voltage hold times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low frequency driving is used to reduce power consumption, then power consumption is reduced, but the storage capacitor voltage hold time increases causing charge leakage and flicker phenomena
Solution Approach 1:
A light blocking structure is introduced as an intermediary element between the external light source and the transistor. This structure blocks light from reaching the transistor, preventing photo-leakage currents while allowing the low frequency driving mode to continue operating with extended voltage hold times
2Loss of time
If the storage capacitor holds voltage for extended periods, then power consumption is reduced, but external light or leakage light causes photo-leakage currents in transistors
Solution Approach 1:
The light blocking structure serves as a mediator that prevents harmful light from reaching the transistor. This allows the storage capacitor to maintain voltage for extended periods without generating photo-leakage currents in the transistor
3Reliability
If transistors are exposed to light, then photo-leakage currents flow causing flicker, but blocking light requires additional structural elements
Solution Approach 1:
The first electrode is designed to perform multiple functions: it serves as the functional electrode for the organic light emitting element while simultaneously acting as a light blocking structure. By extending the electrode to cover the transistor area, it blocks light from reaching the transistor without requiring separate blocking components
Solution Approach 2:
The light blocking function is merged with the electrode structure. The first electrode is extended to overlap with the transistor area, combining the electrical function with the light blocking function in a single integrated structure
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 configuration effectively reduces flicker phenomena even at low frequency driving, maintaining display quality and luminance by blocking light exposure to critical transistors, thus preventing charge leakage and ensuring stable voltage retention.
Implementation Method 1
a first electrode extension part formed so as to block at least a part of the target transistor from light
Implementation Method 2
Electrons injected from one electrode and holes injected from the other electrode are coupled in the organic light emitting layer so as to form exciton and the exciton discharges energy to thereby emit light
Data Source
AI summary
An organic light-emitting diode display is disclosed. In one aspect, the display includes a plurality of pixels formed in a plurality of intersection areas of a plurality of data lines and a plurality of scan lines. Each of the pixels includes a storage capacitor configured to store a data voltage, at least one target transistor having one end electrically connected to a current path of the storage capacitor, an organic light emitting layer, and a first electrode of an OLED formed over the organic light emitting layer. The first electrode includes a first electrode extension configured to block at least a portion of the target transistor from light.