OLED Power Source Voltage Adjustment for Grayscale-Dependent Current Control
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Solution Overview
Problem
In organic light emitting diode (OLED) displays, the driving voltage needs to be adjusted due to temperature changes and degradation over time, leading to increased power consumption and variability in current supply to subpixels, especially when operating in saturation and linear regions.
Innovation Solution
A power source controller calculates a reference power source voltage based on the distribution of grayscale values for each subpixel, modeling voltage drops and adjusting the second power source voltage to optimize the driving voltage, using equivalent resistors and lookup tables to predict and adjust the voltage in real time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driving transistor operates in the saturation region with a fixed power source voltage, then the current control is stable, but the power consumption increases and the driving voltage margin is insufficient when grayscale varies
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed power source voltage to a dynamically adjustable power source voltage that changes according to the grayscale level. The power source controller calculates and adjusts the power source voltage in real-time based on image data grayscale distribution, allowing the system to adapt its voltage level to the actual display requirements, thereby reducing power consumption while maintaining current control stability.
Solution Approach 2:
The patent implements parameter changes by modifying the power source voltage parameter based on grayscale levels. The system calculates the grayscale distribution of image data and adjusts the power source voltage accordingly - using lower voltages for low grayscale values and higher voltages for high grayscale values. This parameter adaptation resolves the contradiction by optimizing power consumption across different display conditions while maintaining adequate driving voltage margin.
2Reliability
If the power source voltage is increased to maintain driving voltage margin for all grayscale levels, then the driving voltage margin is sufficient, but the power consumption increases unnecessarily for low grayscale levels
Solution Approach 1:
The patent applies parameter changes by adjusting the power source voltage according to the grayscale level requirements. Instead of using a high fixed voltage for all cases, the system dynamically changes the voltage parameter - using lower voltages when grayscale levels are low and higher voltages when grayscale levels are high. This resolves the contradiction by providing adequate driving voltage margin only when necessary, thereby reducing unnecessary power consumption.
Solution Approach 2:
The system implements dynamics by making the power source voltage adjustable and responsive to grayscale variations. The power source controller continuously monitors the grayscale distribution and adjusts the voltage in real-time, creating a dynamic system that adapts its power consumption characteristics to the actual display demands while maintaining sufficient driving voltage margin for OLED saturation operation.
3Ease of operation
If a fixed power source voltage is used, then the system is simple to operate, but the current supply to subpixels varies due to OLED degradation and temperature changes
Solution Approach 1:
The patent implements feedback by introducing a power source controller that monitors grayscale distribution and adjusts the power source voltage accordingly. The system receives feedback from the image data characteristics and OLED performance variations due to degradation or temperature changes, and automatically compensates by adjusting the voltage to maintain consistent current supply to subpixels, thereby improving reliability while maintaining ease of operation through automated control.
Solution Approach 2:
The system applies self-service by enabling the power source controller to automatically adjust the power source voltage without manual intervention. The controller autonomously calculates the optimal voltage based on grayscale distribution and OLED characteristics, compensating for degradation and temperature effects automatically. This maintains current supply consistency while preserving operational simplicity, as the system self-regulates without requiring user involvement.
4Use of energy by moving object
If the power source voltage is adjusted dynamically based on grayscale distribution, then the power consumption is reduced, but the device complexity increases due to additional control circuitry
Solution Approach 1:
The patent applies universality by designing the power source controller to perform multiple functions: calculating grayscale distribution, determining optimal power source voltage, and adjusting the voltage output. This multi-functional approach consolidates control operations into a single integrated component, reducing the need for separate dedicated circuits for each function. The controller serves as a universal solution that handles both low and high grayscale scenarios, thereby reducing overall system complexity while achieving power consumption reduction through dynamic voltage adjustment.
Data Source
AI summary
A power system for an organic light emitting diode (OLED) display includes a power supplier and a power source controller. The power supplier respectively supplies a first power source voltage and a second power source voltage to first and second power source voltage application lines. The power source controller calculates a reference power source voltage corresponding to a maximum average grayscale using a distribution for each grayscale of first to third image data, models each voltage drop of the first and second power source voltages for first to third subpixels, and reflects the voltage drop to the reference power source voltage to change the second power source voltage.