OLED Power Supply Voltage Adjustment for Display Quality
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Solution Overview
Problem
Organic light emitting display devices face issues with color blurring and color shift due to variations in light emitting efficiency and response speed among pixels, which are exacerbated by ambient temperature and brightness changes, leading to visibility defects during frame-to-frame image conversion.
Innovation Solution
An organic light emitting display device that includes a power supply system capable of adjusting voltage levels of power supply voltages based on ambient temperature and brightness changes, using a second power supply voltage determiner, delta voltage determiner, and third power supply voltage determiner to optimize the voltage levels for each pixel, ensuring consistent emission characteristics across different conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed power supply voltage is applied to all pixels, then the device structure is simple and power consumption is low, but color blurring and color shift occur due to variations in light emitting efficiency and response speed among pixels under different ambient temperature and brightness conditions
Solution Approach 1:
The patent applies local quality by dividing the display panel into multiple zones (e.g., first, second, and third zones) with different gamma correction characteristics. Each zone has its own gamma correction table that is specifically optimized for its local characteristics, allowing each region to be corrected independently according to its specific performance variations, thereby resolving the color blurring and color shift issues while maintaining manageable system complexity.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the gamma correction values in the gamma correction tables based on ambient temperature and brightness conditions. The system stores multiple gamma correction tables corresponding to different temperature and brightness conditions, and selects or interpolates the appropriate parameters to compensate for pixel variations under specific environmental conditions, thus maintaining display quality consistency without requiring complex real-time control mechanisms.
2Reliability
If gamma correction is applied to compensate for pixel variations, then display quality consistency is improved, but power consumption increases due to additional processing and multiple power supply voltages
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple gamma correction tables that correspond to different ambient temperature and brightness conditions. Instead of performing complex real-time calculations during operation, the system prepares the correction parameters in advance and simply selects or interpolates between the pre-computed tables based on current conditions, significantly reducing processing power requirements and power consumption while maintaining color accuracy.
3Speed
If multiple power supply voltages are used to control different zones, then response speed and display quality are improved, but the device structure and control system become more complex
Solution Approach 1:
The patent applies segmentation by dividing the display panel into multiple independent zones (first zone, second zone, third zone) that can be controlled separately. Each zone has its own gamma correction table and can be adjusted independently based on its specific characteristics, allowing for optimized response speed and display quality in each region without requiring complex inter-zone coordination, thus managing control system complexity effectively.
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 addresses color blurring and color shift by applying optimal forward bias to organic light emitting diodes, maintaining stable black image brightness and improving response speed, thereby enhancing display quality without excessive power consumption.
Implementation Method 1
The organic light emitting diode emits light when a voltage greater than a threshold voltage of the organic light emitting layer is applied between the anode and the cathode
Data Source
AI summary
An organic light emitting display device includes a display panel, a display panel driver, and a power supply. The display panel includes pixels. Each of the pixels includes an organic light emitting diode configured to emit light in an emission period based on a first power supply voltage and a second power supply voltage. The display panel driver is configured to apply a scan signal, an emission control signal, and a data signal to the pixels. The power supply is configured to: generate the first power supply voltage, the second power supply voltage, and a third power supply voltage applied to the pixels in a non-emission period; and adjust a voltage level of the second power supply voltage and a voltage level of the third power supply voltage based on an ambient temperature and a brightness of the display panel.