OLED Display Panel Bias Compensation for Brightness Stability
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Solution Overview
Problem
Existing OLED displays face issues with image brightness stability during transitions, leading to darker regions and poor display quality due to hysteresis effects in driving transistors, which affect the threshold voltage and driving current.
Innovation Solution
A display panel with a switch device connected to a biased compensation voltage terminal, which adjusts the threshold voltage of the driving transistor by providing a biased compensation voltage, stabilizing the electrical performance and ensuring accurate brightness control during image updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional OLED display is used without bias compensation, then the device complexity is low, but the brightness stability during image switching deteriorates and darker regions appear
Solution Approach 1:
The patent applies preliminary action by providing bias compensation voltage to the driving transistor before the light emitting element is driven. This pre-compensation adjusts the threshold voltage of the driving transistor in advance, ensuring that when the image switches from dark to bright, the transistor is already in the correct operating state, preventing the hysteresis effect and brightness instability that would otherwise occur during the transition.
2Speed
If image switching is performed in conventional OLED displays, then the display can show different images, but the brightness changes slowly and takes a long period of time causing poor display quality
Solution Approach 1:
The patent applies preliminary anti-action by using the bias compensation voltage to counteract the hysteresis effect before it manifests as poor display quality. The compensation voltage is specifically designed to offset the threshold voltage shift that occurs during image switching, thereby preventing the slow brightness change and ensuring high display quality from the moment of switching.
3Reliability
If the driving transistor threshold voltage is not compensated, then the circuit is simpler, but the driving current becomes unstable during image switching
Solution Approach 1:
The patent introduces a bias compensation voltage terminal and switch as intermediary elements between the power supply and the driving transistor. These intermediaries provide the necessary threshold voltage compensation without directly complicating the core driving circuit. The switch device acts as a mediator that selectively applies the compensation voltage only when needed during image switching, maintaining driving current stability while minimizing circuit complexity.
Data Source
AI summary
Provided are a display panel, a driving method and a display device. The display panel includes a substrate, a sub-pixel disposed on one side of the substrate and a switch device. A first terminal of the switch device is electrically connected to a first terminal of a driving device, and a second terminal of the switch device is connected to a biased compensation voltage terminal. An image update period includes a data writing stage and a holding stage, and the holding stage includes a first stage and a second stage. The driving device generates a driving current according to a data voltage transmitted by the data writing device in the data writing stage; and the driving device provides the driving current to a light emitting element in the second stage. The switch device provides a biased compensation voltage to the first terminal of the driving device in the first stage.