From the ZEISS lenses blog:
ZEISS is well-known across the globe and the associations with the brand are positive in every respect. Carl Zeiss is the name of the company’s founder and part of the company name Carl Zeiss AG. However, the brand has been called ZEISS for a long time. In general language usage, “ZEISS” is already well established in many countries and languages when referring to both the logo and the company. ZEISS is now taking this development into account in its decision to create consistency across its brand communications. The goal is to create an even clearer and more consistent image of ZEISS in the perception of its customers. ZEISS will be used as much as possible in future to eliminate the lack of consistency in how Carl Zeiss and ZEISS are used...
...As a result, we have decided to use only the ZEISS logo on the front ring of lenses for all future product families and not, as has been the case up to now, the name of the company “Carl Zeiss.” “ZEISS has been a global brand for a long time and we can all be proud of that,” says Martin Dominicus, Head of Marketing of ZEISS Camera Lenses. “When you go on vacation or on a business trip anywhere in the world and mention you work for ZEISS, you are greeted with a smile.”
The changeover for the lenses will take place at the family level: existing lens families will not be changed after-the-fact, but future families will be labeled with ZEISS.
Having known Nokia's association with the full 'Carl Zeiss' brand for much of my career in the smartphone world, this feels a bit like the end of an era. However, it's obviously just a name change and the optics and partnerships will remain in place. Early leaks of the new Nokia 'EOS' (codename) have shown both the full 'Carl Zeiss' and 'ZEISS' names - the latter is much more likely to be on the final device that gets launched on July 11th.
Carl Zeiss branding on the Nokia Lumia 920 and 808 PureView