Three-Stack Storage Capacitor for OLED Aperture Ratio

The patent transitions from a conventional planar two-electrode capacitor to a three-dimensional four-electrode stacked capacitor structure. By stacking multiple capacitor units vertically (adding the Z-dimension), the storage capacity is increased without expanding the planar area, thus maintaining the aperture ratio. The four electrodes are arranged in two stacks, creating multiple overlapping capacitor regions that provide sufficient storage capacity within the same pixel area.

The patent implements a nested capacitor structure where multiple capacitor units are contained within a single pixel region. The first and second capacitors are nested vertically, with their electrodes overlapping in a stacked configuration. This nesting allows the storage capacity to be multiplied while the occupied planar area remains confined to the pixel region, preventing aperture ratio reduction.

The patent designs the four electrodes to serve multiple functions simultaneously. The same electrode structures form both the thin film transistor components and the storage capacitor components. For example, the first and second electrodes serve as both transistor electrodes and capacitor electrodes, eliminating the need for separate capacitor electrode fabrication processes and reducing the total number of mask steps required.

The patent merges the formation of the thin film transistor and storage capacitor into a unified fabrication process. The four electrodes are patterned and formed in the same process sequence, combining what would traditionally be separate fabrication steps into one integrated process flow. This merging reduces manufacturing complexity while achieving the desired high-capacity capacitor structure.