OLED Aging Detection Circuit and Compensation Method
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Solution Overview
Problem
Organic light-emitting diode (OLED) display panels experience decreased luminous brightness due to aging, as increased voltage across the OLED's cathode and anode results in charges being stored in a parasitic capacitor, leading to reduced brightness over time.
Innovation Solution
An aging detection circuit comprising a first and second current mirror circuit, a voltage converter, and an analog-to-digital converter, which detects the charging current of the parasitic capacitor and converts it into a digital signal to determine the OLED's aging degree, and an aging compensation circuit that calculates and applies a data voltage compensation value to maintain optimal brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the OLED is driven for display, then the parasitic capacitor charges first, but the luminous brightness decreases
Solution Approach 1:
The patent extracts the parasitic capacitor charging function from the normal display driving process by introducing a separate detection circuit. The detection circuit includes a detection transistor connected to the anode of the OLED, which can independently detect the anode voltage without interfering with the normal display driving, thus separating the measurement function from the driving function.
Solution Approach 2:
The patent introduces an intermediary detection circuit between the OLED anode and the control circuit. This detection circuit uses a detection transistor and associated components to indirectly measure the anode voltage and aging degree, avoiding direct interference with the OLED's normal operation while providing accurate aging information for compensation.
2Quantity of substance
If the voltage across the OLED increases with aging, then the charge storage in parasitic capacitor increases, but the display brightness decreases
Solution Approach 1:
The patent implements a feedback mechanism where the detection circuit continuously monitors the OLED anode voltage, determines the aging degree, and feeds this information back to the control circuit. The control circuit then adjusts the driving voltage in real-time based on the feedback, creating a closed-loop system that compensates for aging effects and maintains stable brightness.
Solution Approach 2:
The patent changes the driving voltage parameter dynamically based on the detected aging degree. As the OLED ages and the parasitic capacitor charge increases, the control circuit adjusts the driving voltage to compensate for the brightness degradation, thereby maintaining consistent display performance throughout the OLED's lifespan.
3Illumination intensity
If real-time aging detection and compensation is implemented, then brightness consistency is maintained, but the circuit complexity increases
Solution Approach 1:
The patent designs the detection circuit to serve multiple functions: it detects the OLED anode voltage, determines the aging degree, and provides compensation signals. The same detection circuit structure is used across different OLEDs and display panels, making it a universal solution that can be integrated into various display systems without requiring completely separate detection and compensation mechanisms.
Data Source
AI summary
An aging detection circuit, an aging compensation circuit, a display panel, and an aging compensation method are provided. The aging detection circuit includes: a first current mirror circuit, a second current mirror circuit, a voltage converter and an analog-digital converter. An input terminal of the first current mirror circuit is electrically coupled to an initial reference voltage terminal and an anode of a to-be-detected light-emitting diode respectively, and an output terminal of the first current mirror circuit is electrically coupled to an input terminal of the second current mirror circuit. An output terminal of the second current mirror circuit is electrically coupled to an input terminal of the voltage converter.