OLED Display Substrate Electrode Layout for Gate Voltage Stability
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Solution Overview
Problem
In OLED display technology, the increased pixel density and signal line width in high-resolution displays lead to increased resistance and parasitic capacitance, causing signal delay, voltage drop, and voltage rise, which affect display quality. Additionally, instability in the gate voltage of drive transistors due to gate leakage results in uneven brightness and display uniformity issues.
Innovation Solution
A display substrate with a base substrate and sub-pixels arranged in an array, each comprising a pixel circuit with a drive sub-circuit and a compensation sub-circuit. The compensation sub-circuit performs threshold compensation, and the light-emitting element's drive electrode is designed to block the connection portion between the electrodes, improving voltage stability and display uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixel density is increased to achieve high-resolution display, then display quality is improved, but resistance and parasitic capacitance increase causing signal delay and voltage drop
Solution Approach 1:
The patent applies preliminary action by introducing a compensation sub-circuit that performs threshold voltage compensation before the drive transistor operates. The compensation sub-circuit includes a compensation transistor and capacitor that pre-adjust the gate voltage to account for expected threshold voltage variations, thereby compensating for signal degradation before it affects display quality.
Solution Approach 2:
The patent implements feedback through the compensation sub-circuit that monitors and adjusts the gate voltage of the drive transistor. The compensation transistor is controlled by a compensation signal that feedbacks threshold voltage information, allowing the system to dynamically adjust and maintain stable operation despite increased resistance and parasitic capacitance from higher pixel density.
2Reliability
If signal line width is increased to reduce resistance, then voltage drop is reduced, but parasitic capacitance increases causing voltage rise
Solution Approach 1:
The patent applies segmentation by dividing the pixel circuit into distinct functional sub-circuits: a drive sub-circuit and a compensation sub-circuit. This segmentation allows the compensation sub-circuit to specifically address parasitic capacitance effects through dedicated compensation transistors and capacitors, while the drive sub-circuit handles the primary driving function, thereby managing the trade-off between voltage stability and parasitic capacitance.
3Reliability
If gate voltage stability is improved to reduce brightness unevenness, then display uniformity is improved, but threshold voltage offset impact increases
Solution Approach 1:
The patent implements feedback through the compensation sub-circuit that monitors and adjusts the gate voltage of the drive transistor. The compensation transistor is controlled by a compensation signal that feedbacks threshold voltage information, allowing the system to dynamically adjust and maintain stable operation despite increased resistance and parasitic capacitance from higher pixel density.
Solution Approach 2:
The patent applies preliminary action by introducing a compensation sub-circuit that performs threshold voltage compensation before the drive transistor operates. The compensation sub-circuit includes a compensation transistor and capacitor that pre-adjust the gate voltage to account for expected threshold voltage variations, thereby compensating for signal degradation before it affects display quality.
Data Source
AI summary
A display substrate and a display device. The display substrate includes a base substrate and a plurality of sub-pixels on the base substrate. Each sub-pixels includes a pixel circuit. The plurality of sub-pixels include a first sub-pixel. The compensation sub-circuit of the first sub-pixel includes a first electrode, a second electrode, and a connection portion between the first electrode and the second electrode. The first drive electrode of the light-emitting element of the first sub-pixel includes a first main body portion including a first side parallel to a certain direction, and a first protruding portion protruding from the first side of the first main body portion. The first protruding portion at least partially overlaps with the connection portion of the compensation sub-circuit of the first sub-pixel in a direction perpendicular to the base substrate. The light-emitting element of the first sub-pixel is configured to emit green light.