Some more recent Ricoh Patent activity...

http://egami.blog.so-net.ne.jp/2014-11-27
For an adjustable translucent mirror where the amount of reflected and transmitted light can be adjusted (0-50%; 50-100%).

And

http://egami.blog.so-net.ne.jp/2014-12-01
For an 18.3mm F2.8 RF Lens

The RF lens is interesting, either it's for a new GR or they are going to produce some sort of mirrorless camera...

Thank you for the info, great share