Mixed-Transistor Pixel Circuit Layout for Capacitive Coupling Control
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Solution Overview
Problem
As display devices with higher resolutions require more complex pixel circuitry, issues such as capacitive coupling between data lines and gate electrodes lead to potential display quality problems.
Innovation Solution
The display device incorporates a specific configuration of transistors and conductive patterns, including oxide transistors and poly-silicon transistors, along with a storage capacitor and conductive patterns to manage scan signals, data signals, and reference voltages, which helps in reducing capacitive coupling and enhancing display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If higher resolution displays are implemented with more complex pixel circuitry, then display resolution is improved, but capacitive coupling between data lines and gate electrodes increases causing display quality degradation
Solution Approach 1:
A shielding member is introduced as an intermediary element positioned between the data line and the gate electrode. This shielding member acts as a mediator that blocks or reduces the capacitive coupling effect between these two conductive elements, thereby preventing signal interference while allowing the high-resolution display structure to be maintained
Solution Approach 2:
The harmful capacitive coupling effect is extracted or isolated by introducing the shielding member that specifically targets and separates the interaction between the data line and gate electrode. This allows the beneficial high-resolution circuitry to remain while removing the detrimental coupling effect
2Measurement precision
If more transistors are added to each pixel for high resolution, then display resolution is improved, but leakage current increases affecting display quality
Solution Approach 1:
Different transistor types are used in different locations within the pixel circuit. Specifically, the fourth transistor connected to the power line is implemented as a poly-silicon transistor while other transistors may be oxide transistors. This local differentiation allows optimization of each transistor's performance characteristics for its specific function, reducing overall leakage current while maintaining high-resolution capability
Data Source
AI summary
A display device may include a plurality of pixels each including a light emitting element. A first scan line and a second scan line, are disposed in each of the pixels. A data line is disposed in each of the pixels. A power line is disposed in each of the pixels. A reference voltage line is disposed in each of the pixels. A first transistor controls a current of the light emitting element. A second transistor is connected between the data line and a first gate electrode of the first transistor. A third transistor is connected between the reference voltage line and a first electrode of the first transistor. A fourth transistor is connected between the power line and a second electrode of the first transistor. The fourth transistor may be a transistor of a type different from that of the first to third transistors.