OLED Display Control Circuit for Green Pixel Color Dragging
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Solution Overview
Problem
Organic light emitting display devices experience a color dragging phenomenon where green pixels emit light later than red and blue pixels when transitioning from low to high grayscale, degrading display quality.
Innovation Solution
A control circuit that includes an image determiner, boot-up area determiner, and data compensator to identify moving images and compensate low-grayscale values in specific areas of the display panel, using an offset value to generate output image data that mitigates the color dragging phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the green organic light emitting diode uses a large capacitance to achieve high response speed, then the response speed is improved, but the green diode emits light later than red and blue diodes causing color dragging phenomenon
Solution Approach 1:
The control circuit performs preliminary compensation on the green sub-pixel data before display. When transitioning from low grayscale to high grayscale, the control circuit pre-increases the driving current for green sub-pixels based on the grayscale difference, allowing the green diode to reach its emission threshold earlier and synchronize with red and blue diodes, thus eliminating the color dragging phenomenon while maintaining the high response speed advantage
2Reliability
If the control circuit compensates all grayscale values to eliminate color dragging, then display quality is improved, but power consumption increases
Solution Approach 1:
The control circuit applies compensation selectively rather than uniformly across all pixels and grayscale transitions. It identifies specific scenarios where color dragging occurs (low to high grayscale transitions in green sub-pixels) and applies compensation only in those cases. The compensation magnitude is adjusted based on the grayscale difference, applying larger compensation only when needed, thus improving display quality while minimizing unnecessary power consumption
3Reliability
If the control circuit processes and compensates image data in real-time, then color dragging is reduced, but processing complexity increases
Solution Approach 1:
The control circuit extracts and processes only the green sub-pixel data for compensation, separating it from the red and blue sub-pixel processing. This selective approach allows the circuit to focus computational resources on the specific channel causing color dragging, implementing the compensation logic only where needed, thus reducing the overall processing complexity while still achieving color synchronization
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 reduces the color dragging phenomenon, enhancing display quality by ensuring synchronized emission of pixels across different grayscales.
Implementation Method 1
The organic light emitting display device displays an image using an organic light emitting diode that generates light by recombination of electrons and holes
Data Source
AI summary
A display device includes a display panel, a control circuit, and a data driving circuit. The display panel displays an image based on data voltages, and includes a display area divided into a plurality of blocks. The control circuit receives input image data, determines a boot-up area among the blocks when the input image data is a moving image, and generates output image data by increasing low-grayscale values lower than a threshold grayscale among input grayscale values of the input image data in the boot-up area. The data driving circuit generates the data voltages based on the output image data.