OLED Cathode Segmentation and Oxide Barrier for Transmittance

The cathode is divided into multiple thin layers (e.g., first cathode layer with Al, second cathode layer with Ag) instead of using a single thick layer. Each layer has optimized thickness to balance electrical conductivity and light transmittance, resolving the contradiction between these two properties.

The cathode uses composite material structure combining different metals (Al, Ag, Mg, Ca, etc.) in multiple layers. Each material contributes different properties - Al provides good conductivity, Ag enhances transmittance and conductivity, Mg/Ca improve electron injection. This composite approach achieves both high conductivity and high transmittance simultaneously.

The thin cathode is segmented into multiple ultra-thin layers (each layer can be 10-100 Å thick). The cumulative effect of multiple layers provides sufficient conductivity while maintaining high transmittance. The segmentation allows optimization of each layer's thickness to balance both requirements.

Composite material structure with low-resistance materials (Ag, Mg, Ca) combined in multiple layers achieves high conductivity even at reduced total thickness. The synergistic effect of different materials ensures both transmittance and brightness uniformity are maintained.

An oxide layer is introduced as an intermediary between the anode and cathode. This oxide layer acts as an insulating barrier that prevents electrical shorts caused by particles, while allowing the fabrication process to remain simple by not requiring particle removal steps. The oxide layer mediates the interaction between electrodes, eliminating the harmful effect of particles.

The oxide layer is formed beforehand (through exposure to oxygen or ozone before cathode deposition) to cushion against potential electrical shorts. This preventive measure ensures that even if particles remain, they cannot cause short circuits, thus protecting reliability without complicating manufacturing.

The cathode replaces pure Al with composite materials including Ag, Mg, Ca, or their alloys. These materials have superior properties - Ag provides both high conductivity and high transmittance, Mg and Ca enhance electron injection. The composite structure achieves low sheet resistance with much thinner total thickness, maintaining transmittance above 15%.

The cathode is segmented into multiple functional layers with different materials. The first layer (e.g., Al 50-150 Å) provides initial conductivity, the second layer (e.g., Ag 100-300 Å) enhances both conductivity and transmittance. This segmentation allows each layer to be optimized for specific functions, achieving overall low resistance with high transmittance.