OLED Display Current-to-Voltage Compensation Circuit
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Solution Overview
Problem
Existing OLED displays face delays and low reliability in initial driving due to sensing pixel characteristics using small current amplitudes, requiring frame memory and complex compensation methods.
Innovation Solution
The OLED display employs a compensator that converts output currents from pixels into output voltages, allowing for simplified circuit structure and improved compensation reliability by supplying data signals in two phases within a horizontal period, using a data driver and scan driver to manage scan and emission control signals, and a pixel circuit with storage capacitors and transistors to manage current and voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pixel characteristics are sensed using current in initial driving, then compensation can be performed, but the amplitude of current is small resulting in low reliability of compensation
Solution Approach 1:
The patent introduces a conversion circuit as an intermediary component that transforms the small current signal into a voltage signal. This conversion circuit acts as a mediator between the pixel circuit and the compensation mechanism, amplifying the signal strength and improving measurement precision while maintaining the original functional flow.
Solution Approach 2:
The patent changes the parameter of signal representation from current to voltage through the conversion circuit. By transforming the signal parameter, the system achieves better measurement precision and reliability in compensation without fundamentally altering the pixel circuit operation, thus resolving the contradiction between small current amplitude and compensation reliability.
2Reliability
If entire pixel characteristic is sensed in initial driving, then compensation can be stored in frame memory, but a delay occurs and frame memory is required increasing circuit complexity
Solution Approach 1:
The patent extracts the essential compensation information from the full pixel characteristic sensing process. Instead of storing complete pixel characteristics in frame memory, the system extracts only the necessary compensation data through the conversion circuit and processing mechanism, simplifying the circuit structure while maintaining compensation accuracy.
Solution Approach 2:
The patent creates a simplified copy of the pixel characteristic information through the conversion circuit. Rather than storing the complete original characteristic data in frame memory, the system generates a processed copy that contains only the essential compensation information, reducing circuit complexity while preserving the needed functionality.
3Reliability
If data signals are supplied in two phases within horizontal period, then compensation reliability is improved, but the timing control complexity increases
Solution Approach 1:
The patent implements periodic action by supplying data signals in two distinct phases within the horizontal period. This periodic supply mechanism improves compensation reliability by allowing proper signal conversion and processing timing, while the phased approach is integrated into the existing scanning sequence to minimize additional control complexity.
Data Source
AI summary
An organic light emitting diode (OLED) display and a method for driving the same, which can display an image with more uniform luminance is disclosed. In one aspect, the OLED display includes a plurality of pixels arranged in a matrix of a plurality of rows and a plurality of columns; a data driver supplying second data signals corresponding to a second data obtained by converting a first data, in response to first data signals corresponding to the first data or a data control signal; and a compensator converting output currents output from the pixels, corresponding to the first data signals into a output voltages, and supplying, to the data driver, the data control signal for converting the first data into the second data, corresponding to the output voltages and the first data based on the output voltages and the first data.