TFT Drain Electrode Double-Wall Structure for Luminance Uniformity

The drain electrode is divided into three distinct segments (first drain electrode overlapping the gate electrode, second drain electrode extending from the first, and third drain electrode surrounding the second) to create a double-wall structure around the contact hole. This segmentation allows each part to contribute differently to capacitance stabilization, ensuring uniform luminance even when color filters collapse.

The invention transitions from a conventional single-layer drain electrode to a three-dimensional double-wall structure by adding vertical and radial dimensions. The first drain electrode provides top-layer capacitance, while the second and third drain electrodes form a surrounding wall structure that maintains capacitance from multiple spatial dimensions, compensating for color filter collapse.

The invention extracts the capacitance stabilization function from the color filter structure and relocates it to the drain electrode structure. By forming the double-wall drain electrode structure around the contact hole, the capacitance maintenance function is separated from the color filter, allowing the color filter to be simpler and easier to manufacture while the drain electrode handles the capacitance stabilization.

The first drain electrode overlapping the gate electrode acts as an intermediary structure that provides additional capacitance between the gate and source/drain regions. This intermediary capacitance compensates for the collapse of the color filter, maintaining the electrical characteristics needed for uniform luminance without requiring a complex color filter structure.

The invention merges multiple functions into the drain electrode structure: the first drain electrode provides capacitance enhancement by overlapping the gate electrode, the second drain electrode extends to maintain electrical connection, and the third drain electrode surrounds to provide additional capacitance. This merged structure achieves capacitance compensation and electrical connectivity in a single integrated design.

The double-wall drain electrode structure serves multiple functions simultaneously: it provides electrical connection between source and drain, maintains capacitance between gate and drain, compensates for color filter collapse, and ensures uniform luminance output. This multi-functional design achieves capacitance compensation without proportionally increasing device complexity.