Array Substrate Light-Shielding Electrode Capacitance
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Solution Overview
Problem
Existing array substrates for display panels face challenges in achieving optimal capacitance for pixel circuits while minimizing space, leading to potential display issues such as uneven brightness and leakage currents due to variations in threshold voltages of driving transistors and the presence of leakage currents.
Innovation Solution
The array substrate incorporates a base substrate with a light-shielding portion, a thin-film transistor, and a capacitor, where the first capacitive electrode is formed in the same layer as the light-shielding portion, and the second capacitive electrode is formed in the same layer as the active layer, with both electrodes being partially opposite to each other, allowing for increased capacitance without occupying additional space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the capacitor is formed with traditional separate-layer structure, then the fabrication process is simpler, but the capacitance value is insufficient and occupies more space
Solution Approach 1:
The patent merges the first capacitive electrode with the light-shielding portion by forming them in the same layer, and merges the second capacitive electrode with the active layer. This combining approach increases the effective capacitance area without adding separate fabrication steps, thus improving capacitance value while maintaining fabrication simplicity.
Solution Approach 2:
The light-shielding portion serves dual functions: it blocks light from reaching the active layer to prevent unwanted photoconduction, and simultaneously acts as the first capacitive electrode for the storage capacitor. This multi-functionality increases capacitance without occupying additional space or requiring extra fabrication steps.
2Reliability
If the capacitor occupies more space to achieve larger capacitance, then the capacitance value increases, but the display resolution and pixel density decrease
Solution Approach 1:
By merging the capacitive electrodes with existing structural elements (light-shielding portion and active layer), the patent achieves larger capacitance within the same pixel area, thereby increasing capacitance value without sacrificing display resolution or pixel density.
Solution Approach 2:
The patent utilizes the vertical dimension by forming capacitive electrodes in overlapping configurations across different layers (light-shielding portion at bottom, active layer at top), creating a three-dimensional capacitor structure that increases capacitance without expanding the horizontal pixel area.
3Area of stationary object
If the first capacitive electrode is formed in the same layer as the light-shielding portion, then the space utilization is improved, but the fabrication precision requirements increase
Solution Approach 1:
The patent combines the formation of the first capacitive electrode with the light-shielding portion into a single fabrication step, using the same conductive material and patterning process. This approach improves space utilization while actually reducing precision requirements compared to separate formation steps.
Data Source
AI summary
An array substrate, a display panel including the array substrate, and a fabrication method of the array substrate are provided. The array substrate includes a base substrate, a light-shielding portion, a thin-film transistor and a capacitor. The light-shielding portion is formed on a first surface of the base substrate. The thin-film transistor is formed on a side of the light-shielding portion away from the base substrate, and includes an active layer. The capacitor is formed on the first surface of the base substrate, and includes a first capacitive electrode and a second capacitive electrode. The first capacitive electrode and the second capacitive electrode are at least partially arranged opposite to each other in a direction perpendicular to the first surface of the base substrate. The first capacitive electrode is provided in a same layer as the light-shielding portion.