Auxiliary Electrode on Overcoating Layer for OLED Aperture Ratio

The auxiliary electrode is moved from the same layer as the anode to a different layer (overcoating layer), changing the spatial arrangement from two-dimensional co-planar to three-dimensional stacked configuration. This allows the anode opening width to be increased without direct interference from the auxiliary electrode, thereby improving aperture ratio while maintaining manufacturing simplicity through layer-based separation.

By transitioning the auxiliary electrode to a different layer (overcoating layer), the patent utilizes the third dimension (vertical stacking) to maintain device compactness while freeing up horizontal pixel area. The anode can now extend to larger dimensions within the pixel area without conflicting with the auxiliary electrode, as they occupy different vertical levels.

The layer separation approach allows for broader anode openings and better optical characteristics without significantly increasing manufacturing complexity. The auxiliary electrode on the overcoating layer can still be formed using standard photolithography and deposition processes, maintaining manufacturing efficiency while achieving improved image quality through enhanced aperture ratio and light emission characteristics.

By placing the auxiliary electrode on the overcoating layer rather than the same layer as the anode, the patent achieves better device lifetime without substantially increasing structural complexity. The separation allows for optimized electrical fields and reduced stress concentrations, extending device operational life while maintaining a relatively simple multi-layer structure that is still manufacturable using conventional processes.