Source Driver ICs for OLED Luminance Uniformity
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Solution Overview
Problem
Organic light-emitting display devices experience luminance deviations due to voltage drops and resistance differences in the display panel, particularly at the edges, leading to inconsistent light emission and errors in sensing data.
Innovation Solution
The implementation of an organic light-emitting display device with a display panel featuring both driving and sensing transistors, along with source driver ICs that generate and supply sensing voltages, data voltages, and reference voltages, ensuring uniform voltage levels across the panel through a timing controller and digital video data compensator, which adjusts voltages based on area characteristics to prevent voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensing voltage is supplied from C-PCB to the display panel, then the display device can perform external compensation method, but voltage drops occur due to line resistance causing luminance deviation between different areas
Solution Approach 1:
The display panel is divided into multiple areas (first area closer to C-PCB, second area farther from C-PCB), and each area is supplied with different sensing voltages through separate control circuits. This segmentation allows compensation for the voltage drops that occur in different regions, ensuring accurate sensing and uniform luminance across the entire display panel.
Solution Approach 2:
Different sensing voltages are applied to different areas of the display panel based on their specific characteristics. The first area receives a first sensing voltage while the second area receives a second sensing voltage, tailored to compensate for the distance-related voltage drops from the C-PCB, thereby maintaining consistent sensing accuracy and luminance output across all regions.
2Ease of operation
If data voltage and reference voltage are supplied from C-PCB to distant areas of the display panel, then the display device can operate, but high line resistance causes voltage drops leading to luminance reduction at edges
Solution Approach 1:
The system performs preliminary compensation by adjusting the sensing voltages supplied to different areas before actual sensing and display operations. By pre-compensating for the expected voltage drops in distant areas through the timing controller and control circuits, the system ensures that both near and far areas receive appropriate voltages, preventing luminance reduction at edges while maintaining simple operation.
3Device complexity
If the same sensing voltage is supplied to all areas of the display panel, then the voltage supply circuit is simple, but compensation is performed differently due to voltage drops causing luminance deviation
Solution Approach 1:
The sensing voltage supply system transitions from a static, uniform voltage approach to a dynamic, area-specific voltage approach. The timing controller and control circuits dynamically adjust the sensing voltages supplied to different areas based on their distance from the C-PCB, enabling the system to adapt to varying electrical characteristics and maintain luminance uniformity without excessive circuit complexity.
Data Source
AI summary
An organic light-emitting display device includes: a display panel including: a plurality of pixels configured to display an image, each pixel among the plurality of pixels including a driving transistor and a sensing transistor, a plurality of data lines respectively connected to each driving transistor, and a plurality of sensing signal lines respectively connected to each sensing transistor, a plurality of source drive integrated circuits (ICs) configured to: supply data voltages to the plurality of data lines, and supply sensing voltages to the plurality of sensing signal lines, and a timing controller configured to supply digital video data and a data timing control signal to the source driver ICs, wherein each of the plurality of source driver ICs includes a sensing voltage supply unit configured to generate the sensing voltages.