Gamma Setting System for Emissive Displays Using Transfer Functions
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Solution Overview
Problem
Conventional gamma setting methods for emissive display devices of the source current driving type face challenges in accuracy and efficiency due to reliance on lookup tables, leading to deviations in fabrication processes, increased operation time, and limited applicability to various samples, resulting in reduced yield and productivity.
Innovation Solution
A gamma setting system that directly sets gamma resistance and voltage using current efficiency measurements, employing an optical measuring unit, control center, and system driving unit to calculate transfer functions and generate codes for precise luminance and chromaticity adjustments, reducing measurement time and expanding the setting range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional lookup table methods are used for gamma setting, then the process is simple to implement, but the accuracy is limited and fabrication time increases
Solution Approach 1:
The patent changes the fundamental parameter from using fixed lookup tables to using dynamically calculated transfer functions based on measured current efficiency. This allows the gamma setting to adapt to actual device characteristics, improving accuracy while reducing the need for iterative adjustments that consume fabrication time.
Solution Approach 2:
The patent replaces the empirical lookup table approach with a mathematical model (transfer function) that directly calculates gamma settings from measured parameters. This substitution of calculation-based methods for measurement-based methods reduces time loss while improving precision.
2Adaptability or versatility
If lookup table methods are used, then the setting process is straightforward, but the applicability to various samples is limited
Solution Approach 1:
The transfer function approach serves multiple functions: it can handle different device types (OLED, QD-OLED), different gray level ranges, and different efficiency characteristics. This universal method replaces multiple device-specific lookup tables, improving versatility without proportionally increasing complexity.
Solution Approach 2:
The system performs self-characterization by measuring the current efficiency of each device and automatically generating the appropriate transfer function. This eliminates the need for manual calibration and makes the method adaptable to various samples without requiring complex pre-programmed lookup tables for each device type.
3Reliability
If conventional compensation methods are used, then the process is established and reliable, but the yield is reduced due to accuracy limitations
Solution Approach 1:
The patent implements a feedback mechanism where the measured current efficiency directly influences the gamma setting calculation. This closed-loop approach ensures that each device is compensated based on its actual performance, improving yield by reducing defects while maintaining process reliability through systematic measurement and calculation.
Solution Approach 2:
The transfer function is calculated and stored in advance during the fabrication process, allowing gamma settings to be pre-determined before final assembly. This preliminary calculation of compensation parameters ensures accurate settings are ready when needed, improving yield without compromising reliability.
Data Source
AI summary
The present invention provides a gamma setting system for a display device including: an optical measuring unit measuring an optical property of a display device including an emissive display panel having red, green and blue sub-pixels; a control center performing a null setting step and an automatic setting step using the optical property of the display device; a system driving unit transmitting a result data between the display device and the control center; a first display unit displaying a TW target luminance, a TW target chromaticity and an RGB inherent chromaticity registered for the null setting step and the automatic setting step, a graph of a gray level voltage and a luminance of an RGB and a TW with respect to a gray level, a high level cell driving voltage (PVDD) and a low level cell driving voltage (PVEE) applied to an emitting element, a high level gamma source voltage (VDDH) and a low level gamma source voltage (VDDL) applied to a driving IC, a gamma slope, a contrast ratio, a driving type of the system, a gamma setting, an instruction on an execution command, and a progress state of the display device.