OLED Display Driving Method for Brightness Uniformity Compensation
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Solution Overview
Problem
Organic light emitting displays face challenges in maintaining uniform brightness due to variations in threshold voltage and mobility of driving transistors and deterioration of organic light emitting diodes, leading to reduced image quality.
Innovation Solution
The solution involves extracting information on threshold voltage and mobility of driving transistors and OLED deterioration, storing this information in a non-volatile memory, and using it to convert input data into corrected data, which is then used to generate data signals that compensate for brightness variations, thereby improving brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If threshold voltage and mobility variations of driving transistors and OLED deterioration are not compensated, then pixel structure remains simple, but brightness uniformity deteriorates
Solution Approach 1:
The patent extracts compensation information (threshold voltage, mobility, OLED deterioration) from the pixel circuit and stores it in external memory units. This separates the compensation data storage function from the pixel structure itself, allowing simple pixel design while achieving brightness uniformity through external memory-based compensation.
Solution Approach 2:
The patent introduces memory units (first memory unit for threshold voltage/mobility, second memory unit for OLED deterioration) as intermediaries between the pixel circuit and the data processing system. These memory units store compensation information and enable brightness uniformity without adding complexity to the pixel structure itself.
2Reliability
If compensation information is stored in non-volatile memory, then data retention is improved, but access speed deteriorates
Solution Approach 1:
The patent segments the memory storage function into two parts: non-volatile memory for stable retention of compensation information and volatile memory for high-speed access during operation. This segmentation allows the system to benefit from both reliable data retention and fast access speeds by using each memory type for its optimal function.
Solution Approach 2:
The patent adds a temporal dimension to memory usage by storing compensation information in non-volatile memory during non-display periods and loading it into volatile memory for display period operations. This dimensional approach allows the system to achieve both reliable storage and fast access by utilizing different time periods for different memory operations.
3Speed
If compensation information is stored in volatile memory, then access speed is improved, but data retention deteriorates
Solution Approach 1:
The patent performs preliminary action by storing compensation information in non-volatile memory during non-display periods when power is available. This preliminary storage ensures data retention, and then the information is loaded into volatile memory before display operations begin, ensuring both retention and fast access speed are achieved.
Solution Approach 2:
The patent maintains continuity of useful action by continuously managing compensation information between non-volatile and volatile memory during display operations. The system ensures that compensation data is always available in volatile memory for real-time operations while maintaining retention through non-volatile memory, creating a continuous workflow that benefits from both memory types.
4Ease of manufacture
If simple pixel structure is maintained, then manufacturing complexity is reduced, but brightness uniformity compensation capability deteriorates
Solution Approach 1:
The patent makes the memory units serve multiple functions: storing compensation information for threshold voltage, mobility, and OLED deterioration. By consolidating these storage functions into external memory units rather than integrating them into the pixel circuit, the system achieves brightness uniformity compensation without increasing pixel structure complexity or manufacturing difficulty.
Data Source
AI summary
A method of driving an organic light emitting display, includes extracting information on deterioration of an organic light emitting diode (OLED) and information on a threshold voltage and mobility of a driving transistor included in each of the pixels to store the information in a memory unit during a non-display period, converting input data into corrected data using the information items stored in the memory unit, and supplying data signals corresponding to the corrected data to data lines, wherein, extracting the information, includes storing the information on the deterioration of the OLED and the information on the threshold voltage and mobility of the driving transistor in a non-volatile memory, and storing the information in a volatile memory.