OLED Repair Line Voltage Initialization Circuit
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices with repair pixel circuits face issues where the OLED connected to the repair line undesirably emits light during power-up due to voltage differences, affecting image quality.
Innovation Solution
Incorporating a switching circuit that applies a second voltage to the repair line before or at the same time as the first voltage during power-up, initializing the repair line to ensure a voltage difference below the OLED's threshold, preventing unwanted light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a repair line is used to connect the OLED to the repair pixel circuit, then the defective pixel circuit can be replaced and the OLED can be driven normally, but the OLED may undesirably emit light during power-up due to voltage differences on the repair line
Solution Approach 1:
The patent applies preliminary action by initializing the repair line with a specific voltage (second voltage) before the OLED is powered on. The switching circuit sets the repair line voltage to a level that prevents unwanted light emission during power-up, and maintains this initialization until the OLED is ready to operate. This preliminary voltage setup eliminates the harmful light emission that would otherwise occur when power is first applied.
2Device complexity
If the repair line is left floating or at default voltage during power-up, then the circuit structure remains simple, but the OLED emits unwanted light due to voltage difference exceeding the threshold voltage
Solution Approach 1:
The patent introduces a switching circuit as an intermediary component between the repair line and the voltage sources. This switching circuit actively controls the voltage on the repair line during power-up, mediating between the power supply and the repair line to prevent unwanted light emission. The intermediary switching circuit adds minimal complexity while effectively solving the light emission problem.
Data Source
AI summary
An organic light emitting diode (OLED) display device includes a display panel having a display region and a peripheral region, an OLED at the display region and including an end connected to a first voltage, a pixel circuit at the display region, a repair pixel circuit at the peripheral region, a repair line for connecting the repair pixel circuit to the OLED, and a switching circuit configured to apply a second voltage to the repair line during a power-up of the OLED display device.