Curved OLED microdisplays

Technical background for CMOS substrate thinning of CEA-LETI (historically developed for through silicon via technology as well as for more recent activity to provide curved image sensors, for IR as well as for visible spectra) has been applied to realize curved OLED-based microdisplays. It will be shown that test OLEDs made onto silicon wafers as well as 873 x 500 WVGA, 0.38 " diagonal, and an innovative 1920 x 1200 WUXGA, 1 " diagonal, CMOS-based microdisplays can be curved at R = 45 mm radius of curvature (1D) with no negative impact onto the circuit electrical characteristics. This feature can allow significant innovation on the system and application because it can help to redesign simpler and lighter optical engine systems, in the same manner as for curved image sensors. These results can be obtained owing to the integration of a new protective hard coat layer that has been used in conjunction with a robust thin-film encapsulation to protect OLEDs from mechanical ingress (from process steps and handling) and oxidizing gas of the atmosphere, respectively. Results have been produced within the framework of the EU-funded, H2020 project, called Large cost-effective OLED MIcroDisplays (LOMID and their applications).