Dynamic SVDD Voltage Control for OLED Display Power Optimization
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Solution Overview
Problem
Existing organic light emitting display devices face issues with non-uniform image quality due to threshold voltage and mobility deviations in driving TFTs, leading to wasted power consumption and inefficient compensation schemes, particularly in the internal compensation method where a fixed SVDD voltage is used regardless of pixel characteristics.
Innovation Solution
An organic light emitting display device and method that optimize the driving voltage by generating an initial and sequential compensation voltage based on the driving time of the TFT, allowing the data driver to reflect these voltages in the data voltage to create a pixel driving voltage, thereby reducing wasted power and improving compensation accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed SVDD voltage is used regardless of pixel characteristics, then the device complexity is reduced, but power consumption increases due to wasted energy
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed SVDD voltage to a dynamic voltage control system. The data driver now dynamically adjusts the SVDD voltage based on real-time compensation voltage values generated by the compensation circuit, allowing the system to adapt to varying pixel characteristics and reduce power consumption accordingly.
Solution Approach 2:
The patent implements parameter changes by modifying the SVDD voltage parameter based on compensation voltage values. The data driver changes the voltage parameter dynamically according to the compensation circuit's output, which reflects the actual characteristics of each pixel's driving TFT, thereby optimizing power consumption.
2Manufacturing precision
If an internal compensation scheme is used with a compensation circuit inside each pixel, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the compensation circuit from the pixel interior and relocates it to the data driver. This extraction maintains the compensation functionality while reducing the complexity within each pixel circuit, as the compensation calculations are now performed externally at the data driver level.
Solution Approach 2:
The data driver is enhanced with multi-functionality by integrating the compensation circuit functionality directly into it. The data driver now performs both data signal generation and compensation voltage generation, consolidating multiple functions into a single component to reduce overall system complexity.
3Ease of operation
If the same data voltage is applied to all driving TFTs, then ease of operation is improved, but manufacturing precision deteriorates due to non-uniform pixel characteristics
Solution Approach 1:
The patent applies local quality by customizing the gate voltage for each pixel's driving TFT based on its specific characteristics. Instead of using a uniform data voltage, the system generates pixel-specific voltages by adding compensation voltages tailored to each pixel's TFT characteristics, ensuring uniform image quality across the display.
Solution Approach 2:
The compensation circuit implements feedback by sensing the actual characteristics of each driving TFT (such as threshold voltage and mobility) and using this information to generate appropriate compensation voltages. This feedback mechanism ensures that each pixel receives the correct voltage to achieve uniform operation.
Data Source
AI summary
Discussed is an organic light emitting display device. The organic light emitting display device includes a display panel configured to include a plurality of pixels that each include an OLED and a pixel circuit for emitting light from the OLED, a compensation circuit configured to generate an initial compensation voltage of a driving TFT and a sequential compensation voltage based on an elapse of a driving time of the driving TFT, a data driver configured to reflect the compensation voltage in a data voltage based on an image signal to generate a driving voltage that is used to drive the driving TFT included in the pixel circuit, and supply the driving voltage of the driving TFT to each of the plurality of pixels, and a timing controller configured to set a driving voltage of the data driver, based on a sequential compensation voltage at a current time.