OLED Degradation Compensation via Gradual Wake-up Factor Adjustment
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Solution Overview
Problem
Organic light emitting display devices experience luminance variations and image blur due to degradation of organic light emitting diodes and differences in threshold voltage/mobility of driving transistors, leading to noticeable changes in image quality when power is turned on, as compensation factors are calculated after a specific display time.
Innovation Solution
A degradation compensating device that gradually changes the compensation factor during the wake-up period after power on, using an accumulator to accumulate stress data, a memory to load accumulated data, a compensation factor calculator to determine a target compensation factor, and a data compensator to generate image compensation data, ensuring a smooth transition in image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If compensation factor is calculated after loading accumulated data from flash memory, then compensation accuracy is improved, but image quality changes dramatically during wake-up period
Solution Approach 1:
The patent applies preliminary action by pre-calculating the target compensation factor based on accumulated stress data from flash memory before the wake-up period begins. During the wake-up period, the compensation factor is then gradually adjusted from an initial value to the target value, preventing dramatic image quality changes while ensuring accurate compensation is ultimately applied.
Solution Approach 2:
The patent implements dynamics by making the compensation factor adjustable and time-dependent during the wake-up period. The compensation factor transitions dynamically from an initial compensation factor to a target compensation factor based on elapsed time or frame count, allowing smooth adaptation of image quality without abrupt changes.
2Loss of time
If compensation factor is applied immediately after power on, then response time is improved, but compensation accuracy deteriorates due to incomplete data loading
Solution Approach 1:
The system performs preliminary loading of accumulated stress data from flash memory into internal memory before the wake-up period begins. This preliminary action ensures data is ready for immediate processing while the compensation factor is gradually adjusted during the wake-up period, balancing fast response with accurate compensation.
Solution Approach 2:
The compensation factor is made dynamic during the wake-up period, transitioning from an initial value to a target value as data loading and processing progresses. This dynamic adjustment allows the system to respond quickly while progressively achieving accurate compensation based on the loaded accumulated data.
3Reliability
If target compensation factor is applied directly, then compensation effectiveness is improved, but image quality transitions abruptly causing user discomfort
Solution Approach 1:
The patent applies dynamics by implementing a gradual transition mechanism where the compensation factor changes progressively from an initial value to the target value during the wake-up period. This dynamic adjustment maintains compensation effectiveness while ensuring smooth, gradual changes in image quality that are imperceptible to users.
Solution Approach 2:
The system applies beforehand cushioning by preparing a gradual transition schedule during the wake-up period that cushions the transition from initial to target compensation factor. This prevents abrupt changes in image quality that would cause user discomfort, while still achieving the full compensation effect by the end of the wake-up period.
Data Source
AI summary
A degradation compensating device includes an accumulator configured to accumulate stress data every pixel block, a memory configured to receive the stress data from the accumulator, and to load accumulated data from an external flash memory when a display device power is turned on, the accumulated data being a total sum of the stress data, a compensation factor calculator configured to determine a target compensation factor based on the accumulated data to compensate image data, and to apply an initial compensation factor to the target compensation factor during a wake-up period after loading the accumulated data is completed, the initial compensation factor being changed gradually during the wake-up period, and a data compensator configured to generate image compensation data based on the target compensation factor, and to generate initial image data based on a wake-up factor that is an adjusted target compensation factor based on the initial compensation factor.