OLED Display Anode Discharge Circuit for Sleep Mode Flickering
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Solution Overview
Problem
Existing OLED displays experience abnormal screen flickering when transitioning from sleep-in mode to sleep-out mode due to excessive charging of pixels, leading to unwanted light emission.
Innovation Solution
The OLED display incorporates a panel driving circuit that reduces the reference voltage applied to the anode of the OLED to a ground level in sleep-out mode and adjusts it to a voltage greater than ground in normal driving mode, preventing abnormal light emission by discharging the anode in sleep-out mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operation mode is converted from sleep-in mode to sleep-out mode, then the display panel transitions to operational state, but each pixel is overly charged to anode voltage and emits light abnormally causing screen flickering
Solution Approach 1:
The patent applies preliminary action by discharging the anode of each pixel to ground level voltage before the sleep-out mode is activated. This is achieved through a discharge circuit that is enabled during mode transition to remove excess charge from the anode, preventing the abnormal light emission that would otherwise occur when the display panel transitions from sleep-in to sleep-out mode.
2Adaptability or versatility
If voltage driving is used to control OLED pixels, then the display can operate in different modes, but excessive charging of anode voltage causes abnormal light emission during mode transition
Solution Approach 1:
The patent introduces an intermediary discharge circuit that mediates the voltage transition during mode conversion. This circuit includes discharge transistors that are activated during the transition from sleep-in to sleep-out mode to provide a controlled discharge path for the anode voltage, preventing excessive charging and the resulting screen flickering while maintaining the ability to operate in different modes.
3Speed
If the anode voltage is maintained at driving level during sleep-out mode, then the display can respond quickly to input, but pixels are overly charged and emit light abnormally
Solution Approach 1:
The patent implements periodic action through controlled voltage transitions. The anode voltage is periodically discharged to ground level during mode transitions (specifically during sleep-out mode activation) and then restored to driving level for normal operation. This periodic discharge prevents excessive charging and abnormal light emission while maintaining the capability for quick response during normal driving mode.
Data Source
AI summary
An organic light emitting diode (OLED) display includes a display panel including data lines, scan lines crossing the data lines, and light emitting cells, which are arranged in a matrix form and each include an OLED, and a panel driving circuit, which reduces a reference voltage applied to an anode of the OLED to a ground level voltage in a sleep-out mode and adjusts the reference voltage at a voltage level greater than the ground level voltage. The reference voltage is held at a voltage level greater than the ground level voltage in a normal driving mode.