OLED Display Panel Dummy Sub-Pixel Threshold Drift Compensation
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Solution Overview
Problem
The threshold value drift in transistors of OLED display panels due to environmental influences affects the control of scan signals, leading to inconsistent display effects.
Innovation Solution
A display panel design incorporating a dummy sub-pixel with the same internal configuration as display sub-pixels, connected through feedback and compensation lines to a driver chip, which generates compensation signals to maintain current signals at preset threshold values, ensuring consistent light emission across the panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a scan driver circuit is used to control transistors in the pixel driving circuit, then the display panel can operate with a standard driving structure, but the threshold value drift of transistors causes the scan signal to fail in controlling transistors to turn off, resulting in poor display effect
Solution Approach 1:
The patent introduces a feedback mechanism where the current signal from the light-emitting element is fed back to the driver chip. The driver chip compares this feedback signal with a preset threshold and generates a compensation signal when the threshold is not met, thereby compensating for the transistor threshold drift and ensuring reliable transistor control.
Solution Approach 2:
The patent introduces a driver chip as an intermediary component between the scan driver circuit and the pixel driving circuit. This driver chip processes the feedback signal and generates compensation signals to correct transistor threshold drift, thereby improving control reliability without changing the overall standard driving structure.
2Measurement precision
If a dummy sub-pixel with the same internal configuration as display sub-pixels is added, then the current signal feedback and compensation can be achieved, but the device complexity increases due to additional components and connections
Solution Approach 1:
The patent creates a dummy sub-pixel that is a copy of the display sub-pixel structure, containing the same light-emitting element and pixel driving circuit configuration. This copy allows for accurate measurement of current signals under the same environmental conditions without requiring complex external measurement equipment.
Solution Approach 2:
The dummy sub-pixel serves multiple functions: it acts as a reference for threshold drift measurement, provides a feedback signal source, and enables compensation signal generation. This multi-functionality reduces the need for separate measurement and control systems, thereby limiting the increase in device complexity.
Data Source
AI summary
A display panel includes a display area and a non-display area surrounding the display area. The display area includes a plurality of display lines and a plurality of display sub-pixels arranged in arrays. The non-display area further includes a dummy sub-pixel, a driver chip, a feedback line and a compensation line. The driver chip is used for acquiring a current signal of a light-emitting element in the dummy sub-pixel through the feedback line, and generating a compensation signal when the current signal fed back by the feedback line is not equal to the preset threshold value, and also for generating a display compensation signal when the current signal fed back by the feedback line is equal to the preset threshold value, and the display compensation signal is transmitted to the pixel driving circuit of the display sub-pixel through the display line.