Patent Law

Drafting "consisting essentially of" claims to overcome unknown anticipatory prior art

By DC Patent Associate

In the original claims of U.S. Patent Application No. 10/314,993 (now U.S. Patent No. 6,946,097) is recited,

Claim 1. A soft magnetic Fe-Co alloy comprising, in weight %,

Fe and Co such that the difference between the Fe and Co is at least 2%,

at least 35% Co, and

2.5% =< (V+Mo+Nb), wherein 0.4% =< Mo and/or 0.4% =< Nb.

In the First Office Action, claims 1, 2, 4-11, 13-15, 19-21, 28 and 29 were rejected as being anticipated by JP 09-228007 to Nagasaki et al.  Specifically, Nagasaki disclosed exemplary alloy no. 35 having the composition by weight %:  49% Co, 2% V, 0.1% C, 2% Al, 2% Si, 2% Ga, 2% Cr, 2% Mo, 2% W, 2% Ti, 2% Nb, 2% Ni and 2% Cu, with the balance of ~29% being Fe, thereby unarguably anticipating claims 1, 2 and 4-9.  Accordingly, claim 1 was amended and eventually allowed and issued.

Suppose the following hypothetical.  Suppose the Examiner never discovered Nagasaki and allowed and issued the original claims.  Suppose the patentee sued an infringer and the opposing party discovered Nagasaki.  Or suppose the patentee wished to sue an infringer and discovered Nagasaki before filing suit.  In these instances, the invalidity of claims 1, 2 and 4-9 due to Nagasaki would significantly reduce the enforceable claim scope.

One possible solution to this problematic hypothetical would have been to draft additional claim(s) including the transitional phrase "consisting essentially of".  {The transitional phrase "consisting essentially of" limits the scope of a claim to the specified materials or steps "and those that do not materially affect the basic and novel characteristic(s)" of the claimed invention. In re Herz, 537 F.2d 549, 551-52, 190 USPQ 461, 463 (CCPA 1976) (emphasis in original).}  Thereby, the patentee gains the opportunity to argue that the differences in the composition of alloy no. 35 somehow results in not achieving the basic and novel characteristics of the claimed invention.  If the argument is successful, then the claim(s) including "consisting essentially of" would not be anticipated (although could still be deemed obvious, but at least the patentee may get to the jury).

It seems to me that with alloy composition claims such as in this case, the risk of anticipatory prior art not being discovered by the Examiner is high.  At the very least, including one dependent claim including "consisting essentially of" seems well worth the excess claim fee and would not require much extra work on the part of attorneys.

Yet only approximately one quarter of applications to new alloy compositions filed this decade include "consisting essentially of" claims.  {A first search in class 420 (Alloy and Metallic Compositions) for "inevitable impurities" (an indicator of patents with novelty relying on composition) resulted in 176 applications. A second search also including the term "consisting essentially" resulted in 33 applications.  The USPTO Published Applications Database includes all applications published since March 15, 2001.}

Do you believe "consisting essentially of" claims would be helpful during litigation to overcome otherwise anticipatory prior art?  Should "consisting essentially of" claims be included in every application directed to a new alloy composition?  To every application directed to a new composition?  What other types of applications should routinely include "consisting essentially of" claims?

Full post as published by Benefit of Hindsight on January 09, 2008 (boomark / email).