OLED Pixel Power-Line Muxing for Faster Gate Voltage Settling
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Solution Overview
Problem
In OLED display devices, hysteresis in the driving transistor occurs due to voltage differences during the initialization and sampling periods, leading to reduced response speed and inadequate luminance of the light-emitting diode.
Innovation Solution
A mux signal with a voltage close to the data signal is supplied to the gate electrode of the driving transistor during the initialization period, and a method is implemented to minimize hysteresis and improve response speed by using a timing controlling circuit, data driving circuit, and gate driving circuit to generate specific signals for the display device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a high level voltage signal is supplied to the gate electrode during initialization period, then the transistor is fully turned on for initialization, but hysteresis occurs due to voltage difference with data signal
Solution Approach 1:
The patent applies preliminary action by initializing the gate electrode with a voltage close to the data signal voltage (rather than a high level voltage) before the data signal is applied. This preliminary initialization at a similar voltage level prevents the formation of hysteresis, allowing the transistor to respond quickly and accurately to the data signal without voltage transition delays.
2Stability of the object's composition
If a high level voltage signal is supplied to the gate electrode during initialization period, then the transistor is fully turned on, but the gate electrode does not reach target voltage during sampling period
Solution Approach 1:
The patent changes the voltage parameter used for initialization from a high level voltage to a voltage close to the data signal voltage. This parameter change ensures that when the data signal is applied during the sampling period, the gate electrode is already at a similar voltage level, minimizing the voltage difference and enabling the gate to reach the target voltage quickly without hysteresis-induced delays.
3Stability of the object's composition
If a high level voltage signal is supplied to the gate electrode, then initialization is performed, but the light emitting diode does not emit light of predetermined luminance
Solution Approach 1:
The patent performs preliminary initialization of the gate electrode at a voltage close to the data signal voltage before the data signal is applied. This preliminary action ensures that the transistor operates in a stable region without hysteresis effects, allowing it to accurately control the current through the light emitting diode and achieve the predetermined luminance specified by the data signal.
Data Source
AI summary
A display device includes a timing controlling circuit configured to generate image data, a data control signal and a gate control signal; a data driving circuit configured to generate a data signal using the image data and the data control signal and generate a mux signal using an offset signal, a high level voltage signal and the data signal; a gate driving circuit configured to generate gate signals, emission signals using the gate control signal; and a display panel including pixels that are configured to display an image using the data signal, the mux signal, the gate signals, and the emission signals, wherein the mux signal is one of the high level voltage signal and voltage that is a sum of the data signal and the offset signal, and the mux signal is supplied to a power line that is connected to a pixel included in the display panel.