OLED Display Compensation Circuit for Luminance Uniformity
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Solution Overview
Problem
Active matrix OLED displays face luminance differences among pixels due to temperature changes and degradation, affecting the characteristics of driving transistors, which complicates the display device hardware with the need for exponentiation or division operations.
Innovation Solution
An organic light emitting diode display with a compensator that senses driving currents, compares reference and actual currents, updates compensation data, and adjusts mobility and threshold voltage characteristics to generate corrected data signals, simplifying the hardware configuration and reducing compensation processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If exponentiation operation or division operation is used to compensate data signal, then luminance difference among pixels can be reduced, but display device hardware becomes complicated
Solution Approach 1:
The patent replaces complex floating point operation circuits with simple lookup tables that store pre-calculated compensation values. These lookup tables act as simplified, static substitutes for complex real-time calculation hardware, reducing circuit complexity while maintaining compensation effectiveness.
Solution Approach 2:
The patent pre-calculates compensation values for various threshold voltage and mobility parameter combinations and stores them in lookup tables before operation. This preliminary action eliminates the need for complex real-time exponentiation and division operations, simplifying the hardware while achieving the same compensation goal.
2Manufacturing precision
If floating point operation circuit or lookup table is used, then luminance difference can be compensated, but compensation processing time increases
Solution Approach 1:
The patent uses simplified lookup tables instead of complex floating point operation circuits, which reduces processing time despite the additional data retrieval step. The lookup tables provide direct access to pre-calculated values, avoiding time-consuming exponentiation and division operations.
3Stability of the object's composition
If driving transistor characteristics change due to temperature and degradation, then pixel luminance consistency deteriorates, but compensation complexity increases
Solution Approach 1:
The patent implements a compensation system that senses actual pixel characteristics, compares them with reference values, and adjusts data signals accordingly. This feedback mechanism continuously corrects for temperature and degradation effects, maintaining luminance consistency without requiring overly complex hardware.
Solution Approach 2:
The patent replaces complex real-time calculation systems with pre-calculated lookup tables that store compensation values for various operating conditions. This approach handles temperature and degradation variations efficiently without increasing hardware complexity.
Data Source
AI summary
An organic light emitting diode display including a display including data lines, scan lines, sense lines, and pixels electrically coupled to the data, scan, and sense lines, a compensator for sensing first and second driving currents flowing to the pixels corresponding to first and second test data in a compensation mode, to compare first and second reference currents with the first and second driving currents, respectively, and to update compensation data, a signal controller for compensating input data according to the compensation data to generate image data, and for changing the input data into the first and second test data in the compensation mode; and a data driver for generating a plurality of data signals by using one of the image data, the first and second test data, and to supply the data signals to the data lines.