Shielding Pattern for Compensation Transistor Channel in OLED Substrates
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Solution Overview
Problem
Existing rigid liquid crystal screens fail to meet user requirements due to lack of flexibility, leading to a need for flexible organic light-emitting diode (OLED) displays that offer advantages such as flexibility, lightness, low power consumption, fast response, and wide viewing angles.
Innovation Solution
A display substrate is designed with a base and multiple sub-pixels, each containing a sub-pixel driving circuit and a light-emitting element. The sub-pixel driving circuit includes a driving transistor and a compensation transistor, where the compensation transistor's channel portion is shielded by a shielding pattern to reduce photo-induced leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the compensation transistor channel is exposed to light, then the display can be viewed, but photo-induced leakage current increases causing residual images and flicker
Solution Approach 1:
The patent introduces a shielding pattern as an intermediary element between the light source and the compensation transistor channel. This shielding pattern selectively blocks light from reaching the channel region while allowing the display to function normally, thereby preventing photo-induced leakage current without compromising display operation.
Solution Approach 2:
The patent extracts the harmful light exposure from the compensation transistor channel by introducing a separate shielding structure. The shielding pattern is positioned to specifically cover the channel region, separating the light-blocking function from the transistor structure itself and eliminating the harmful effect of light-induced leakage.
2Reliability
If a shielding pattern is added to block light from the compensation transistor channel, then photo-induced leakage current is reduced, but device complexity increases
Solution Approach 1:
The patent merges the shielding pattern with existing display structures such as the pixel definition layer or conductive layers. By integrating the light-blocking function into already-present structural elements rather than adding completely separate components, the design reduces overall device complexity while maintaining effective shielding of the compensation transistor channel.
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 shielding of the compensation transistor's channel portion effectively reduces photo-induced leakage current, enhancing the stability of the voltage at the N1 node and improving display quality by preventing residual images and flicker.
Implementation Method 1
at least a portion of the shielding pattern is located between the pixel definition layer and the gate electrode of the compensation transistor, and an orthographic projection of the shielding pattern onto the base at least partially overlaps with an orthographic projection of a channel portion of a corresponding compensation transistor onto the base
Data Source
AI summary
Display substrate and display device are provided. The display substrate includes: a base and sub-pixels thereon, the sub-pixel includes a light-emitting element and a sub-pixel driving circuit including a driving transistor and a compensation transistor; the compensation transistor has a first electrode coupled to a second electrode of the driving transistor, and a second electrode coupled to a gate electrode of the driving transistor; the compensation transistor includes a gate electrode and an active layer including a channel portion; the display substrate includes a pixel definition layer and shielding patterns, at least a portion of the shielding pattern is located between the pixel definition layer and the gate electrode of the compensation transistor, and an orthographic projection of the shielding pattern onto the base at least partially overlaps with an orthographic projection of corresponding channel portion of the compensation transistor onto the base.