Display Timing Control for OLED Afterimage Compensation
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Solution Overview
Problem
Display devices, such as liquid crystal or organic light emitting displays, experience afterimages due to the deterioration of light emitting elements over time, which affects image quality and reliability.
Innovation Solution
A display device and method that accumulates age information based on current supplied to light emitting elements, using a timing controller to generate corrected data and apply compensation factors to enhance afterimage compensation, including a current sensor to measure global current values and a scale factor generator to adjust pixel luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If age information is accumulated based on current amount supplied to light emitting elements, then reliability of afterimage compensation is improved, but device complexity increases due to additional sensors and control circuits
Solution Approach 1:
The display device uses its own driving current as the basis for age information accumulation, eliminating the need for external sensors or separate measurement systems. The current amount supplied to light emitting elements is already available from the driving circuit, so no additional sensing components are required.
Solution Approach 2:
The existing driving circuit that supplies current to light emitting elements is made to serve dual purposes: both driving the elements and providing age information for compensation. The same current path is used for both operation and aging tracking.
2Manufacturing precision
If current sensor and scale factor generator are added to measure and adjust current, then luminance consistency is improved, but manufacturing complexity increases
Solution Approach 1:
The system uses the existing driving current as the reference for age information, eliminating the need for separate current sensors. The current already flowing through the light emitting elements during normal operation is utilized directly for compensation calculations.
Solution Approach 2:
Age information is extracted from the driving current that is already present in the system, rather than adding separate measurement infrastructure. The compensation mechanism extracts and utilizes existing electrical parameters for its purpose.
Data Source
AI summary
A display device includes pixels connected to scan lines and data lines, each pixel including a driving transistor and at least one light emitting element, and a timing controller configured to generate output data using external input data. The timing controller includes a first compensator configured generate first data by correcting the external input data using at least one of optical measurement information, a threshold voltage of each of the driving transistors, mobility information, dimming information, and temperature information, and an afterimage compensator configured to generate second data based on age information of each light emitting element and the first data, generate third data based on a current amount corresponding to the first data and a current amount corresponding to the second data, and generate the age information by accumulating the third data.