We haven't seen truly flexible curved display yet, though some of the more drastically curved displays has already arrive. LG G Flex and Samsung Galaxy Round are the instances of this type. Now, we all are waiting for true curved display, as per the latest rumors suggests 2015 will be the year.
Industry sources claimed that during CES 2014 Samsung secretly showed off a 5.64'' flexible display but only to some analysts, VIPs, and potential clients. The clients who attended this secret presentation reported that Samsung's display technology has really got advanced.
Currently we don't know when Samsung will reveal this technology globally. Its said that Samsung will use this true display technology in its next-gen curved display smartphone. Hope we see it in this year only.