Olympus mZD 5-20mm f/1.8-2.8 lens
see also:
a catalogue of Micro Four Thirds lenses
introduction
patent
only as of Feb 2015 gives various options of configurations including:
5-20mm f/1.8-2.8
5-20mm f/2.0-f/3.0
5-24mm f/1.8-f/3.0
5-24mm f/2-f/3.1
5-24mm f/1.9-3.0