Means plus function claims
Citing a Federal Circuit decision in Intellectual Science and Technology v. Sony Electronics earlier this week, Dennis Crouch (Patently-O) first says that there is a "a long line of cases warning against the use of means-plus-function claim language," but then notes that "[t]here is nothing 'wrong' with writing means-plus-function claim language -- especially to accompany a well drafted specification."
I think the second position is probably better than the first. While means+function claims can be narrowly construed during litigation, they can nevertheless be valuable during licensing and assertion.
However, from a patent prosecution perspective, they can be difficult to appeal to the Board of Patent Appeals and Interferences because of the additional requirements the appeals rules impose on such claims. As a result, some patent practitioners prefer to avoid such claims, while others add them to broaden out the claims in applications.
The case demonstrates, however, that asserting a means+function claim requires a clear explanation of infringement on the record.
