Luminance and image quality analysis of an organic electroluminescent panel with a patterned microlens array attachment

Abstract

Luminance and image quality observed from the normal direction of a commercial 2.0 inch panel based on organic electroluminescence (OEL) technology attached to regular and patterned microlens array films (MAFs) were studied and analyzed. When applying the regularly arranged MAF on the panel, a luminance enhancement of 23% was observed, accompanied by a reduction of the image quality index as low as 74%. By removing the microlenses on the emitting areas, the patterned MAF enhances the luminance efficiency of the OEL by 52% keeping the image quality index of the display as high as 94%, due to the effective light extraction in the glass substrate being less than the critical angle. 3D simulation based on a ray-tracing model was also established to investigate the spatial distribution of light rays radiated from an OEL pixel with different microstructures which showed consistent results with the experimental results.

Curved Mirror Arrays for Light Extraction in Top-Emitting Organic Light-Emitting Diodes

“…An ideal TEOLED design for light extraction should minimize the SPP modes while extracting light from the waveguide modes using microlens arrays ,, and scattering layers. − Unfortunately, the use of a microlens array can lead to pixel blurring due to redirected light propagating out of the device in the non-emitting area . In addition, as the organic layers are soft, attaching microlens on top could damage the OLED pixels.…”

“…31−35 Unfortunately, the use of a microlens array can lead to pixel blurring due to redirected light propagating out of the device in the nonemitting area. 36 In addition, as the organic layers are soft, attaching microlens on top could damage the OLED pixels. To address these issues as well as reduce the SPP loss, one successful scheme is to replace the bottom electrode with a transparent electrode, a spacer layer, and a reflective scattering layer.…”