OLED microdisplays: Advanced functionality and systems
OLED-on-CMOS microdisplays can be used for near-to-eye (NTE) applications such as viewfinders of cameras or head-mounted displays (HMD). Especially in see-through HMD applications it would be helpful if the user has a possibility to interact with the display content in an augmented reality setting while preserving hands-free operation. Such user interaction can be handled by an eye-tracker based on an integrated near-infrared (NIR) camera. Therefore integration of NIR camera photodetectors and AMOLED microdisplay into a single device will lead to a highly integrated, very light-weight, small-sized bi-directional microdisplay ("OLEDCAM"), which can be used as visual Input-/Output-Device (I/O) For personal information management (PIM) (see Fig. 1). Applications could be in mobile communication (connected to smartphone), industry (worker assistance), medicine (surgeon assistance), security (surveillance, pilots), barrier-free operation (handicapped people), travel/transport (driver assistance, tourist information), or others). The use of OLEDs in active matrix CMOS substrates requires a top-emitting, low voltage and highly efficient OLED stack. Bi-directional AMOLED microdisplays potentially require high-speed OLED switching behaviour (<100µs), since display and eye tracker camera, and to minimise distortion in the eye-tracker camera. A first prototype of a bi-directional OLED microdisplay device has been designed, that combines both display and camera functionality on a single CMOS chip (OLED-on-CMOS). Major aim of this integration is to provide small form-factor display and eye-tracking for see-trough HMD applications (augmented reality).