OLED Pixel Compensation Using Return-Line Characterization
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Solution Overview
Problem
Display devices using organic light-emitting diodes (OLEDs) face issues with luminance uniformity due to variations in transistor characteristics across pixels, leading to inconsistent current flow and image quality degradation.
Innovation Solution
A display device and method that includes a data driver to apply a measurement reference voltage, measure pixel characteristics, and generate compensation voltages based on pixel-specific data to ensure uniform luminance by compensating data signals using pixel characteristic data and ideal co-relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a voltage corresponding to the same data is applied to multiple pixels, then the data transmission is simplified, but the currents flowing through the pixels become different due to transistor characteristic variations, resulting in deteriorated luminance uniformity
Solution Approach 1:
The patent applies local quality by measuring and compensating for pixel-specific characteristics. Each pixel's transistor characteristics are individually measured using return lines to obtain pixel-specific data, and compensation values are calculated and applied to each pixel's data signal. This ensures that each pixel receives a customized data signal tailored to its specific characteristics, thereby achieving uniform luminance across the display panel while maintaining simplified overall data transmission architecture.
2Illumination intensity
If pixel characteristics are measured and compensated for each pixel, then luminance uniformity is improved, but the device complexity and measurement operations increase
Solution Approach 1:
The patent introduces return lines as intermediary elements that enable pixel characteristic measurement without adding significant complexity. These return lines are used to measure the characteristics of light-emitting elements by providing a path for measurement currents. The measurement results are then used to generate compensation values that are applied to the data signals. This intermediary approach allows for accurate pixel-specific compensation while maintaining a relatively simple overall system architecture.
3Measurement precision
If pixel characteristics are measured using return lines, then accurate pixel-specific data is obtained, but the measurement process and data processing time increase
Solution Approach 1:
The patent applies preliminary action by measuring pixel characteristics in advance during a dedicated measurement period before normal display operation begins. The pixel-specific data obtained from these preliminary measurements is stored and used to generate compensation values that are applied during subsequent display operations. This approach allows for accurate measurement without continuously interrupting normal display functionality, thereby minimizing time loss while maintaining high measurement precision.
Data Source
AI summary
A display device includes a display panel including a plurality of pixels connected to a plurality of data lines and a plurality of return lines; a timing controller that generates a first image data corresponding to a first selection pixel connected to a first data line among the plurality of data lines and a first return line among the plurality of return lines; and a data driver that applies a first data signal corresponding to a measurement reference voltage to the first selection pixel through the first data line, measures a characteristic of the first selection pixel based on a first return signal received through the first return line, and generates a second data signal corresponding to the first image data based on the characteristic of the first selection pixel.