OLED Cell Diffusion Layer with Hollow Cylinders for Light Extraction

The patent introduces a diffusion layer containing an array of cylindrical pores (hollow cylinders) with specific dimensions (radius R between λ/10 and λ/5, height h between λ/2 and 2λ) into the OLED cell structure. These porous structures act as phase filters that modify the optical path of photons, enabling those emitted at angles greater than the critical angle to be redirected into the light cone and escape the device. This porous architecture transforms the homogeneous high-index medium into a structured composite material that actively manages photon propagation, thereby significantly improving light extraction efficiency while adding controlled structural complexity.

The patent employs parameter changes by precisely controlling the geometric parameters of the cylindrical pores in the diffusion layer. The radius R is set between λ/10 and λ/5, and the height h is set between λ/2 and 2λ, where λ is the wavelength of emitted light. These specific parameter ranges optimize the phase filtering effect, allowing the structure to redirect photons effectively without requiring overly complex designs. By tuning these parameters, the patent achieves improved light extraction efficiency through a relatively simple and manufacturable structure.

The patent divides the diffusion layer into an array of discrete cylindrical pores with regular spacing and uniform dimensions. This segmentation approach allows for systematic manufacturing using standard lithography and etching techniques. Each cylinder acts as an independent phase filter element, and their collective arrangement creates the desired optical effect. The regular geometry and periodic structure simplify fabrication compared to irregular geometric patterns, reducing manufacturing precision requirements while still achieving high light extraction efficiency and enhanced illumination intensity.