Display Substrate Pixel Circuit for Fast Charging at High Refresh
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Solution Overview
Problem
Existing display technologies face challenges in achieving high refresh rates due to insufficient charging time, leading to defects such as high black state voltage and poor threshold sensitivity, particularly when increasing the refresh rate to 144 Hz or 165 Hz.
Innovation Solution
A display substrate design incorporating a pixel drive circuit with a compensation transistor, drive transistor, data writing transistor, and storage capacitors, along with a specific electrode and signal line configuration, including a mesh structure for initial signal transmission, to enhance data writing and threshold compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the refresh rate is increased to 144 Hz or 165 Hz, then the display performance is improved, but the charging time becomes insufficient leading to high black state voltage and poor threshold sensitivity
Solution Approach 1:
The pixel drive circuit is divided into multiple functional blocks including first and second storage capacitors (C1, C2), compensation transistors (T2, T6), drive transistors (T3, T7), and data writing transistors (T4, T8). This segmentation allows independent optimization of charging paths and timing control, enabling sufficient charging time even at high refresh rates of 144 Hz or 165 Hz by separating the charging function into multiple staged operations.
Solution Approach 2:
The first storage capacitor C1 performs preliminary charging of the gate electrode of the drive transistor during the data writing period, before the second storage capacitor C2 completes the charging. This preliminary action ensures that the gate electrode receives adequate charge voltage in advance, preventing high black state voltage and poor threshold sensitivity even when the overall charging time is constrained by high refresh rates.
2Speed
If the refresh rate is increased to 144 Hz or 165 Hz, then the display performance is improved, but defects such as high black state voltage and poor threshold sensitivity occur
Solution Approach 1:
The compensation transistors (T2, T6) are configured to perform threshold voltage compensation by comparing the actual threshold voltage of the drive transistor with a reference value and adjusting the gate voltage accordingly. This feedback mechanism ensures that threshold sensitivity is maintained at high refresh rates by continuously compensating for voltage variations and transistor parameter changes that occur during high-speed operation.
Solution Approach 2:
The first storage capacitor C1 performs preliminary charging of the gate electrode during the data writing period, establishing a baseline gate voltage before the emission period begins. This preliminary action prevents high black state voltage by ensuring the gate electrode is properly charged in advance, thereby maintaining reliable threshold sensitivity even at 144 Hz or 165 Hz refresh rates.
3Device complexity
If the pixel drive circuit uses conventional configuration, then the circuit complexity is low, but the data writing efficiency and threshold compensation are insufficient
Solution Approach 1:
The pixel drive circuit is segmented into multiple specialized transistors and capacitors including first and second storage capacitors (C1, C2), compensation transistors (T2, T6), drive transistors (T3, T7), and data writing transistors (T4, T8). This segmentation enables independent optimization of data writing and threshold compensation functions, significantly improving data writing efficiency and compensation accuracy despite the increased circuit complexity.
Solution Approach 2:
The first storage capacitor C1 is configured to perform preliminary charging of the gate electrode during the data writing period, before the emission period begins. This preliminary action improves data writing efficiency by pre-establishing the gate voltage, allowing the second storage capacitor C2 to complete the charging during the emission period, thereby achieving efficient data writing and accurate threshold compensation.
Data Source
AI summary
A display substrate and a driving method therefor, and a display device. The display substrate comprises a plurality of circuit units, at least one circuit unit comprising a pixel driving circuit, which at least comprises a compensation transistor, a driving transistor, a data writing transistor, a first storage capacitor, and a second storage capacitor, wherein a gate electrode of the data writing transistor is connected to a first scan signal line; a gate electrode of the compensation transistor is connected to a second scan signal line; a first end of the first storage capacitor is connected to a gate electrode of the driving transistor; a first end of the second storage capacitor is connected to a first electrode of the driving transistor; and a second end of the first storage capacitor and a second end of the second storage capacitor are connected to a first power line.