Very High Brightness, High Resolution CMOS Driving Circuit for Microdisplay in Augmented Reality

Abstract : In augmented reality applications, high brightness at high resolution is crucial to guarantee a good user experience. Explorations on efficient light sources have already been undertaken, and GaN µLEDs tend to be a good candidate. Nevertheless, micro-display driving circuits usually do not provide sufficient luminance level to offer good contrast against ambient light. We report the design and fabrication of a GaN LED microdisplay driving circuit enabling, to our knowledge, the highest brightness for such a pixel pitch and resolution. The driving circuit was designed in a 0.18µm CMOS process with 1640x1033 resolution. Each LED is controlled individually by a CMOS pixel of 9.5µm pitch. A monochrome green microdisplay enables more than WSXGA resolution and can reach 3.8MCd/m² for a fully ON micro-LED array.