Power Manager Voltage Compensation for OLED Luminance Uniformity
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Solution Overview
Problem
Organic light-emitting display devices face issues with voltage IR drop, which affects the luminance and discharge characteristics of light-emitting elements, leading to potential delays in light emission and afterimages due to changes in initialization and supply voltages.
Innovation Solution
A display device and method that include a power manager with voltage change and difference sensors, a supply voltage compensator, and a generator to sense and correct voltage drops in the pixel area, maintaining a preset voltage difference between initialization and supply voltages, thereby stabilizing the discharge characteristics of light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If voltage is supplied to the pixel area without compensation, then the display device can operate, but voltage IR drop occurs causing non-uniform luminance and discharge characteristics
Solution Approach 1:
The power manager pre-calculates and compensates for the voltage IR drop before supplying voltage to the pixel area. By measuring the current through the EL and predicting the voltage drop using stored resistance information, the system adjusts the supply voltage in advance to ensure uniform luminance across the display panel.
Solution Approach 2:
The system implements a feedback mechanism where the power manager continuously monitors the current through the light-emitting element and adjusts the supply voltage accordingly. The measured current information is fed back to the power manager, which uses this data to calculate and compensate for voltage drops in real-time, maintaining consistent luminance output.
2Reliability
If initialization voltage and supply voltage are supplied without compensation, then the pixel can be driven, but the voltage difference changes causing delays in light emission and afterimages
Solution Approach 1:
The power manager pre-establishes the correct voltage difference between initialization voltage and supply voltage by compensating for IR drops in both voltage lines. This preliminary compensation ensures that when the pixel operates, the voltage difference remains constant, preventing light emission delays and afterimage effects without requiring complex real-time adjustments.
3Manufacturing precision
If voltage compensation is implemented using sensors and compensators, then luminance uniformity is improved, but the device complexity increases
Solution Approach 1:
The voltage compensation function is merged with the existing power manager that supplies voltages to the pixel area. Rather than adding a separate compensation circuit, the invention integrates the compensation logic into the power management system by storing resistance information and using it to calculate compensated voltages, thereby reducing overall device complexity.
Solution Approach 2:
The power manager performs self-compensation by using its own current measurement capabilities and stored resistance data to calculate and adjust the supply voltage. The system serves its own voltage regulation needs internally without requiring external compensation circuits, reducing the overall system complexity while maintaining luminance uniformity.
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
The solution effectively compensates for voltage IR drops, maintaining uniform discharge characteristics and preventing luminance issues, facilitating the implementation of High Dynamic Range (HDR) and improving optical performance.
Implementation Method 1
a voltage change sensor configured to output a first offset voltage based on a first sensing voltage, wherein the first sensing voltage is a voltage difference between an input and an output of the first supply voltage
Implementation Method 2
a first supply voltage generator configured to change the first supply voltage based on the reference feedback voltage and supply the same to the pixel area
Implementation Method 3
An organic light-emitting display device displays an image using an organic light-emitting diode (OLED) that generates light through recombination of electrons and holes
Data Source
AI summary
Provided herein may be a display device and a driving method thereof. The display device may include a pixel area including multiple pixels, a timing controller configured to generate a control signal based on an input image, a data driver configured to supply a data voltage to data lines coupled to the pixel area depending on the control signal, a scan driver configured to supply scan signals to scan lines coupled to the pixel area depending on the control signal, and a power manager configured to supply an initialization voltage for initializing the multiple pixels and a first supply voltage for driving the multiple pixels to the pixel area. The power manager senses a voltage change in the first supply voltage supplied to the pixel area, and changes the first supply voltage and supplies the same to the pixel area in order to compensate for the sensed voltage change.