[Update] -The general consensus is that the OM-D E-M5 uses a Sony made sensor, and that is interesting for a number of reasons. When I attended the launch of the Pen E-P3 in Vienna, Austria the rumor beforehand was that sensor was made by a rival to Panasonic, but when it was subsequently announced at 12-megapixel, everyone (me included) assumed the sensor was from the same source. But what if it wasn't? And what if the sensor used a four-colour filter array; R, Gr, B and Gb (emerald)? Who might have made that?
At first I discounted reports that the Olympus OM-D E-M5 carried a Sony made sensor, simply because it requires a huge investment to fabricate a new format like this for a single camera manufacturer, let alone a single model. But the Japan based site, DC Watch are reporting the comments made about Sony as the fab-maker by the Olympus President were directed towards the camera and not a microscope, which was apparently the subject being discussed at that time. Sony is a supplier of sensors for the maker's digital compact cameras, as well as their microscopes it seems, but we're still really none the wiser concerning the origins of the sensor in the OM-D EM-5. A spokesperson for Olympus UK declined to comment.