Thanks again Yoshi.
Pops - most of the big camera makers in Japan have medical imaging divisions. Olympus is the world leader in endoscopes and famously developed a pill-sized wireless camera that you swallow
It's Olympus' lucrative medical imaging business that is the attraction rather than the camera division which has been a loss-maker in recent years. Indeed, although Olympus is best known for cameras the company first started as a manufacturer of microscopes before WW2.
When Hoya bought Pentax they were only interested in the Pentax medical imaging division and the acquisition of Pentax Cameras by Ricoh was minus the medical division.
Sony is not a major player in medical imaging, and neither is Panasonic so Olympus is attractive to them for those reasons but Panasonic is going through a bad patch with very poor sales of TVs and associated products, so Panasonic can't currently afford a stake in Olympus. Sony has also suffered with the problematical TV sector, but seems more focused on Olympus.