Optoelectronic sensors based on OLED-on-CMOS
Highly-efficient, low-voltage organic light emitting diodes (OLED) are well suitable for post-processing integration onto the top metal layer of CMOS devices. The use of OLED on CMOS substrates requires a top-emitting, low-voltage and highly efficient OLED structure. So far OLED-on-CMOS application has been limited to microdisplays only. By the use of integrated photodetectors, low-cost CMOS processes and simple packaging, new optoelectronic microsystems with combined sensors and actuating elements can be realized. They can be used for optical integrated circuits (OIC's), for fiber optics, to measure temperature, distance or fill level as well as to transfuse optical signals (optocoupler, optical data communication). Furthermore they can be used for applications which react to failures in optical paths (light barriers) or to capture physical properties of objects by reflection of light (colour-, flow-, contrastor luminescence sensors). We developed an optical microsystem with three different types of sensors: a color, flow and reflection sensor. A corresponding demonstrator shows the functionality of combined sensors and actuating elements based on OLED and CMOS integration. The silicon chip was manufactured in a commercial 1micrometer CMOS technology. The integration of the OLED's takes place in the production line of the IPMS.