The universal special formal ${\mathcal{O}}_D$-module for $d=2$

A new proof of an old theorem of Drinfeld concerning the representability of the moduli problem of special formal ${\mathcal{O}}_D$-modules by Deligne’s $p$-adic formal model of Drinfeld’s upper half-plane is given for $d=2.$ The display associated to the universal object is constructed explicitly.