OLED Pixel Current Measurement Using Shared Data Line Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In organic light emitting diode (OLED) displays, variations in transistor characteristics across pixels due to process deviations lead to differences in luminance, making it difficult to accurately measure and compensate for pixel currents, especially with noise interference from parasitic components.
Innovation Solution
A display device and driving method that uses a sensor to detect pixel currents by comparing sensing currents from adjacent pixels without a separate feedback line, allowing for accurate measurement and compensation of pixel currents through a sensing capacitor and comparator, and a data compensator to adjust data signals based on detected currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate feedback line is used to measure pixel current, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the pixel current measurement function with the existing data line structure. The sensor is integrated into the data line circuit, allowing the same data line to serve both data transmission and current measurement purposes. This eliminates the need for a separate feedback line while maintaining measurement capability through the sensing capacitor and comparator circuitry embedded in the data line path.
Solution Approach 2:
The data line is designed to perform multiple functions: it transmits data signals to pixels and simultaneously serves as the measurement path for sensing pixel current. The sensor circuitry shared by adjacent pixels enables the data line to carry both functional loads without requiring dedicated separate lines for each function.
2Manufacturing precision
If current measurement is performed to compensate for luminance differences, then display uniformity is improved, but device complexity increases due to feedback lines
Solution Approach 1:
The patent combines the current measurement function with the data line infrastructure. By integrating the sensor into the data line circuit and using shared sensing capacitor and comparator resources from adjacent pixels, the system achieves current measurement capability without adding separate feedback line infrastructure, thus maintaining manufacturing precision while controlling device complexity.
3Measurement precision
If noise from parasitic components is present, then measurement precision deteriorates, but adding filtering circuits increases device complexity
Solution Approach 1:
The patent uses the sensing capacitor to create a copy of the pixel current signal. By capturing the current information in the sensing capacitor and then using the comparator to compare this copied signal with reference values, the system can process the measurement data without being directly exposed to continuous noise interference, improving measurement precision without requiring complex filtering circuits.
Solution Approach 2:
The sensor performs the current measurement and stores the result in the sensing capacitor before the actual compensation process. This preliminary action separates the measurement phase from the compensation phase, allowing noise present during measurement to be captured and processed separately, thereby improving measurement precision without adding complex filtering.
Data Source
AI summary
A display device includes: a plurality of pixels, each being coupled to a corresponding data line among a plurality of data lines and a corresponding scan line among a plurality of scan lines; a scan driver to supply a scan signal to the scan lines; a sensor coupled to the pixels and the data lines and configured to detect a sensing current according to a test signal input to the data lines; and a controller configured to detect a pixel current of a pixel corresponding to a scan line to which the scan signal is supplied, by using a first sensing current corresponding to a first pixel and a second sensing current corresponding to a second pixel, when the scan signal is selectively supplied to a first scan line coupled to the first pixel and a second scan line coupled to the second pixel.