OLED Burn-in Prevention via Equivalent Cumulative Energy Correction
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Solution Overview
Problem
Existing organic EL display devices face challenges in preventing burn-in and suppressing time degradation of OLEDs, particularly due to increased drive currents, which accelerate degradation and require a large number of wires for compensation.
Innovation Solution
A data processing device that calculates an equivalent cumulative value of energy for each pixel circuit, using a correction coefficient to adjust gradation data, thereby reducing drive current and minimizing time degradation, while also considering temperature-induced degradation and integrating current measurements to optimize luminance compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a large drive current is applied to compensate for time degradation, then luminance is maintained, but time degradation accelerates and burn-in occurs
Solution Approach 1:
The patent applies preliminary action by calculating the equivalent cumulative value and determining correction coefficients in advance before actual display output. The data processing device pre-processes the image data to determine appropriate current adjustments for each pixel based on historical degradation patterns, preventing burn-in before it occurs rather than reacting to it later
Solution Approach 2:
The patent changes parameters by introducing an equivalent cumulative value parameter that reflects both current magnitude and duration, and by using correction coefficients to adjust drive currents. This transforms the simple luminance control into a multi-parameter optimization problem that balances luminance maintenance with degradation prevention
2Measurement precision
If correction data is stored for each pixel circuit, then luminance compensation precision is improved, but memory capacity increases
Solution Approach 1:
The patent applies universality by making the correction coefficient applicable to multiple pixels with similar degradation characteristics. Instead of storing separate correction data for every pixel, the system uses a limited number of correction coefficients that can be applied to groups of pixels based on their equivalent cumulative values, reducing memory requirements while maintaining compensation effectiveness
Solution Approach 2:
The patent applies local quality by providing differentiated correction coefficients to different pixels or pixel groups based on their specific equivalent cumulative values. Pixels with higher equivalent cumulative values receive different correction levels than those with lower values, optimizing compensation precision locally while managing overall memory usage
3Device complexity
If a simple matrix system is used, then device structure is simplified, but large size and high precision are difficult to realize
Solution Approach 1:
The patent applies parameter changes by introducing equivalent cumulative values and correction coefficients to the simple matrix system. This transforms the control parameters from simple voltage signals to multi-dimensional data including historical degradation information, enabling high precision compensation without changing the physical matrix structure
4Illumination intensity
If drive current is increased to maintain luminance, then display brightness is maintained, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating equivalent cumulative values and determining correction coefficients before actual display operation. This allows the system to optimize power consumption in advance by selecting the minimum necessary current adjustments to maintain luminance, rather than using excessive current margins
Solution Approach 2:
The patent changes parameters by using equivalent cumulative values that incorporate both current magnitude and time duration. This allows the system to maintain luminance with lower instantaneous currents by spreading the energy delivery over time, reducing peak power consumption while achieving the same visual result
Data Source
AI summary
A unit equivalent value acquiring unit acquires a normal-temperature unit equivalent use time Δtn by using a temperature sensor, first to third LUTs, and a first multiplying unit. An integration unit acquires an equivalent cumulative use time to by integrating the normal-temperature unit equivalent use time Δtn. A maximum value detecting unit detects a maximum equivalent cumulative use time tnmax. A dividing unit acquires a correction coefficient Kcmp by dividing total degradation E(tnmax,Tn) acquired by a fourth LUT by total degradation E(tn,Tn) acquired by a fifth LUT. Accordingly, there is provided a data processing device for a display device capable of preventing burn-in while suppressing time degradation of an electro-optical element and increase in the number of wires.