OLED Power Voltage Adjustment via Measured Current Feedback
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Solution Overview
Problem
Organic light emitting display devices face issues with luminance changes due to degradation of organic light emitting diodes and ambient temperature variations, leading to inefficiencies in current-voltage characteristics and digital driving techniques.
Innovation Solution
A method of driving the organic light emitting display device involves generating a target voltage signal based on input image data, measuring and compensating the output current, and adjusting the power voltage using a simple circuit configuration to maintain target current levels, employing a first-order linear equation and differential amplification to control the current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constant voltage driving is performed with higher data voltage considering degradation, then the display device can maintain operation, but current efficiency is lowered
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual current flowing through the OLED and comparing it with the target current value. Based on this comparison, the power voltage is dynamically adjusted to compensate for device degradation and maintain both reliable operation and optimal current efficiency.
Solution Approach 2:
The patent transitions from static constant voltage driving to dynamic voltage adjustment. The power voltage is continuously modified based on measured current values and target current requirements, allowing the system to adapt to degradation while optimizing energy efficiency.
2Illumination intensity
If higher data voltage is applied to compensate for degradation, then luminance can be maintained, but power consumption increases
Solution Approach 1:
The system measures the actual current through the OLED and uses this feedback to adjust the power voltage, ensuring that luminance is maintained through optimal current control rather than simply increasing voltage, thereby reducing unnecessary power consumption.
Solution Approach 2:
The patent dynamically changes the power voltage parameter based on measured current and target current requirements, optimizing the balance between luminance output and power consumption rather than using fixed high voltage.
3Device complexity
If simple circuit configuration is used, then device complexity is reduced, but compensation speed may be limited
Solution Approach 1:
The patent pre-calculates target current values based on image data and stores them for quick retrieval. This preliminary preparation allows the simple circuit to respond quickly to luminance changes without requiring complex real-time calculations.
Solution Approach 2:
The patent replaces complex mechanical or analog compensation circuits with a digital control approach, using digital signal processing and lookup tables to achieve fast compensation with minimal circuit complexity.
Data Source
AI summary
A method of driving an organic light emitting display device includes performing a digital driving on a display panel supplied with a first power voltage through a first power supply line, generating a target voltage signal of the first power voltage by analyzing input image data provided to the display panel, measuring an output current that flows through the first power supply line, and changing the first power voltage based on a measured output current and the target voltage signal.