OLED Gamma Correction Unit for Luminance Consistency
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Solution Overview
Problem
Variations in manufacturing processes for organic light emitting displays result in inconsistent luminance and color across the display, leading to defective products and reduced yield, as the same gamma correction value may not adequately address differences in light emitting layer thickness, efficiency, and thin film transistor characteristics.
Innovation Solution
An organic light emitting display with a gamma correction unit, circuit, and drivers that include a first and second register unit, a booster unit, and multiplexers to generate and correct gamma correction signals, allowing for a wider range of gamma correction and improved image quality by adjusting gray level voltages and selecting appropriate signals for each pixel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed gamma correction value is used, then the device complexity is reduced, but the manufacturing precision deteriorates due to variations in light emitting layer thickness and efficiency
Solution Approach 1:
The patent implements dynamic gamma correction by replacing a fixed gamma correction value with a variable gamma correction signal that can be adjusted based on manufacturing variations. The gamma correction unit generates different gamma correction signals corresponding to different luminance levels, allowing the system to adapt to variations in light emitting layer thickness and efficiency, thereby maintaining consistent image quality across different manufactured displays.
Solution Approach 2:
The patent changes the gamma correction parameter from a fixed value to a variable signal with multiple levels. By introducing a gamma correction signal that can take different values (first gamma correction signal and second gamma correction signal) based on the actual display characteristics, the system can compensate for manufacturing variations in light emitting layer properties and thin film transistor characteristics, improving luminance and color consistency.
2Device complexity
If manufacturing variations are not compensated, then the device complexity remains low, but the productivity decreases due to reduced yield from defective goods
Solution Approach 1:
The patent applies preliminary correction by incorporating gamma correction signals into the display system before final assembly and testing. By pre-establishing multiple gamma correction signals that correspond to different manufacturing conditions, the system can compensate for variations in light emitting layer thickness and efficiency before the display is deemed defective, thereby reducing waste and improving production yield.
3Device complexity
If gamma correction range is limited, then the device complexity is reduced, but the adaptability deteriorates for handling manufacturing variations
Solution Approach 1:
The patent extends the gamma correction range by implementing a dynamic correction system that can adapt to different manufacturing conditions. The gamma correction unit generates multiple gamma correction signals (first and second signals) that can be selected based on the actual display characteristics, allowing the system to handle a wider range of manufacturing variations in light emitting layer thickness, efficiency, and thin film transistor characteristics.
Data Source
AI summary
An organic light emitting display and a driving method thereof, capable of increasing manufacturing yield by widening a range of gamma correction. An exemplary organic light emitting display includes a display region with pixels at crossings of data and scan lines; a gamma correction unit; a gamma correction circuit; a data driver; and a scan driver. The gamma correction unit includes first and second register units for storing first and second gamma correction signals, the second gamma correction signal comprising a corrected first gamma correction signal; a booster unit for correcting the second gamma correction signal to generate a third gamma correction signal; and a multiplexer for selecting the second gamma correction signal or the third gamma correction signal outputted from the booster unit, and for transferring it to the gamma correction circuit.