Bidirectional OLED microdisplay: Combining display and image sensor functionality into a monolithic CMOS chip

Abstract

Microdisplays based on organic light-emitting diodes (OLEDs) achieve high optical performance with excellent contrast ratio and large dynamic range at low power consumption. The direct light emission from the OLED enables small devices without additional backlight, making them suitable for mobile near-to-eye (NTE) applications such as viewfinders or head-mounted displays (HMD). In these applications the microdisplay acts typically as a purely unidirectional output device [1-3]. With the integration of an additional image sensor, the functionality of the microdisplay can be extended to a bidirectional optical input/output device. The major aim is the implementation of eye-tracking capabilities in see-through HMD applications to achieve gaze-based human-display-interaction

Aspects of a head-mounted eye-tracker based on a bidirectional OLED microdisplay

“…A bidirectional microdisplay combines camera and display functionalities into one application-specific integrated circuit (ASIC) [1]. It is an active-matrix OLED display that can also capture images.…”

Optical system designs based on bi-directional sensor devices

“…6,9 This display technology benefits from small geometrical size, low weight, low power consumption and potentially high resolution. 14 High brightness OLED microdisplays (>2.000cd/m 2 ) can also be applied as image generating devices in pico-projectors (e.g.…”

“…Further information can be found in. 9,11,15 With this device, either simultaneous or sequential emission (OLED projection) and detection (photo diode) can be realized. 15 Futher, there are two different kind of BiMiDs.…”

“…Such a bi-directional OLED microdisplay (BiMiD) is realized using OLEDon-CMOS-technology by Fraunhofer IPMS. [8][9][10] The image generating element is placed in the same plane as the detector matrix. The bi-directional display used in these system designs consists of an AM-OLED microdisplay with an integrated photo diode matrix.…”

“…First applications which are based on a similar working bi-directional OLED sensor are a flow-, color-, and reflex sensor which presented in Reckziegel et.al. 8 A further metrology application of a distance and inclination sensor is mentioned in Grossmann et al 11 Another application based on a BiMiD which works in different wavelength ranges for the OLED imaging and photo diode detection is a HMD presented by in Richter et al 9 and Herold. 12 This system can be used in the automotive, engineering and multimedia sector.…”