Display Device Pixel Circuit Initialization and Sensing
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Solution Overview
Problem
Display devices with light emitting diodes face issues of dark lines and bright lines due to uneven initialization and sensing of pixel potentials, leading to variations in luminance across the display panel.
Innovation Solution
A display device with a sensing circuit that samples and initializes pixel potentials during blank periods, using multiple initialization and sampling circuits to ensure consistent potential discharge across the panel, preventing dark and bright lines by adjusting the duration of rewriting and readout periods based on the distance from the sensing circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single initialization circuit is used for all pixels, then the circuit complexity is low, but dark lines and bright lines appear due to non-uniform potential discharge across the panel
Solution Approach 1:
The initialization circuit is divided into multiple independent initialization circuits, each responsible for a specific region or group of pixels. This segmentation allows each circuit to independently discharge potentials to its designated pixels, ensuring uniform potential distribution across different regions of the display panel and preventing dark lines and bright lines.
Solution Approach 2:
Different initialization circuits are configured with different initialization voltages or timing characteristics according to their local requirements. This local quality approach addresses the non-uniform potential distribution problem by tailoring the initialization parameters to specific regions, thereby achieving uniform luminance across the entire display panel.
2Measurement precision
If the sensing period is extended to improve sensing accuracy, then the measurement precision increases, but the display refresh rate decreases
Solution Approach 1:
The sensing operation is performed periodically during blank periods between display frames. By utilizing the blank periods when no display signal is being output, the sensing circuit can conduct pixel characteristic measurements without interfering with the normal display refresh operation, thus maintaining both high measurement precision and high refresh rates.
Solution Approach 2:
Pixel potential sensing and initialization are performed in advance during the blank period before the next display frame begins. This preliminary action ensures that pixel potentials are properly initialized and sensed before display operations start, allowing accurate sensing without compromising the display refresh timing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents dark and bright lines by ensuring uniform initialization and discharge of pixel potentials, improving luminance consistency across the display panel.
Implementation Method 1
the sensing circuit senses a potential of the first node through the corresponding readout line during a blank period
Implementation Method 2
displays an image using a light emitting diode that generates light by recombination of electrons and holes
Data Source
AI summary
In a display device, each of pixels includes a light emitting element and a pixel circuit which is connected to the light emitting element at a first node and drives the light emitting element in response to a corresponding driving scan signal among driving scan signals during a display period. The pixel circuit is connected to a corresponding readout line among readout lines at a second node. The sensing circuit senses a potential of the first node through the corresponding readout line during a blank period, and each of frames includes the display period and the blank period. At least two driving scan signals among the driving scan signals respectively include a plurality of rewriting periods, each of which is activated during the blank period corresponding thereto, and the rewriting periods of the driving scan signals have different durations from each other.