OLED Display Substrate Vertical Electrode Overlap
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Solution Overview
Problem
In high-resolution OLED displays, the increased density of sub-pixels and signal lines leads to higher resistance and parasitic capacitance, causing signal delay, voltage drop, and uneven display quality due to threshold voltage offset in pixel circuits.
Innovation Solution
A display substrate with a base substrate and an array of sub-pixels, each comprising a pixel circuit with a drive sub-circuit and a compensation sub-circuit. The compensation sub-circuit performs threshold compensation and includes a connection portion that overlaps with the drive electrode of the light-emitting element, improving voltage stability and display uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the density of sub-pixels and signal lines is increased to achieve high-resolution display, then the display resolution is improved, but the resistance and parasitic capacitance increase causing signal delay and voltage drop
Solution Approach 1:
The patent introduces a new spatial dimension by extending the drive electrode to overlap with the connection portion of the compensation sub-circuit in the vertical direction (perpendicular to the base substrate). This three-dimensional electrode configuration increases the effective overlapping area without expanding the planar footprint, thereby enhancing capacitance compensation and voltage stability while maintaining high sub-pixel density for high-resolution display.
2Measurement precision
If the density of sub-pixels and signal lines is increased to achieve high-resolution display, then the display resolution is improved, but signal delay and voltage drop occur
Solution Approach 1:
The extended drive electrode creates additional overlapping area with the compensation sub-circuit connection portion in the vertical dimension, increasing capacitance compensation effectiveness. This reduces the RC time constant by enhancing the compensating charge storage capacity, thereby mitigating signal delay effects while maintaining the high sub-pixel density required for high-resolution displays.
3Reliability
If threshold compensation is performed to improve display uniformity, then the voltage stability is improved, but the device complexity increases
Solution Approach 1:
The patent integrates the compensation function directly into the existing drive electrode structure by extending it to overlap with the connection portion of the compensation sub-circuit. This merging of the drive electrode with the compensation mechanism eliminates the need for separate compensation electrodes or additional circuit layers, thereby achieving effective threshold compensation and voltage stability without proportionally increasing device complexity.
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.