Olympus filed an interesting patent in Japan for removing water drops from a lens by using a vibrating front element:
Here are another four patents applications for the following Olympus m4/3 lenses (also filed in Japan):
- M.Zuiko 17mm F2.8 (already available)
- M.Zuiko 20mm F2.8
- M.Zuiko 14mm F2.8
- M.Zuiko 12mm F3.5