Transfer printing using ultrasound

Abstract

Embodiments of the invention pertain to methods useful in transfer printing of small objects, like micro-LEDs from one substrate to another using acoustic or ultrasonic energy. The pickup of objects from a substrate is performed by transfer head equipped with sticky polymer and an array of ultrasonic transducers, and the high efficiency and selectivity of pickup of selected objects is done using ultrasonic energy directed towards the object. The disposing of objects to another substrate from a transfer head is done by directing an ultrasonic energy toward an object, which enable effective and selective detachment of an object from a sticky polymer. Yet another embodiment also uses a UV light source, which directs the light to the UV curable liquid disposed around the object on receiving substrate, thus curing this liquid would attach an object to receiving substrate.