OLED Driving Current Uniformity in Low Frequency Mode
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Solution Overview
Problem
Organic light emitting display (OLED) devices face display defects such as flicker when operated in low frequency driving mode, due to non-uniform driving current, which affects brightness and stability.
Innovation Solution
The OLED device divides high power voltage into two levels, with a second power provider including a static current circuit and voltage compensator to maintain uniform driving current by adjusting voltage levels based on detected current, and a switch block to toggle between normal and low frequency modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If OLED device operates in low frequency driving mode, then power consumption is reduced, but display stability deteriorates due to non-uniform driving current causing flicker
Solution Approach 1:
The patent changes the voltage parameter dynamically by introducing a voltage compensator that adjusts the voltage level based on detected driving current. In low frequency mode, the compensator increases voltage to counteract current non-uniformity, thereby maintaining display stability while preserving low power consumption benefits
Solution Approach 2:
The patent implements a feedback mechanism through the sensing block that continuously monitors driving current and feeds this information to the voltage compensator. This closed-loop control enables real-time adjustment of voltage to maintain uniform driving current and prevent flicker in low frequency operating conditions
2Stability of the object's composition
If voltage level is increased to compensate for current decrease, then driving current uniformity is improved, but power consumption increases
Solution Approach 1:
The patent applies partial compensation by introducing a second power provider that provides only the compensatory voltage portion rather than full voltage. The voltage compensator adjusts voltage only to the extent necessary to compensate for current non-uniformity, avoiding excessive voltage increase and associated power consumption
Data Source
AI summary
An organic light emitting display device includes a display panel including pixels that includes an organic light emitting diode that emits light based on a driving current, a data driver providing a data signal to the pixels through a data line, a scan driver providing a scan signal to the pixels through a scan line, an emission control driver providing an emission control signal to the pixels through an emission control line, a first power provider providing a first high power voltage to the pixels through a first power providing line and a second power provider providing a second high power voltage to the pixels through a second power providing line and coupled to the first power provider. The second power provider includes a static current circuit that maintains the driving current having uniform value when the display panel is operated in a low frequency driving mode.