When do patent claim preambles limit a claim? Should an Applicant merely recite the statutory classification in the preamble (e.g., “an apparatus comprising” or “a method comprising”) without anything further, or should the patent practitioner include a limited description of the invention along with a statement of purpose? What about statements of purpose or intended use that are included in a claim preamble?
Overview and General Rule for Patent Claim Preambles
The Federal Circuit has held that “No litmus test defines when a preamble limits claim scope.” Corning Glass Works v. Sumitomo Elec. U.S.A., Inc., 868 F.2d 1251, 1257, 9 USPQ2d 1962, 1966 (Fed. Cir. 1989). Instead, the court has held that whether to treat a preamble as a limitation is a determination “resolved only on review of the entirety of the patent to gain an understanding of what the inventors actually invented and intended to encompass by the claim.” Id. Catalina Mktg. Int’l v. Coolsavings.com, Inc., 289 F.3d 801, 808, 62 USPQ2d 1781, 1785 (Fed. Cir. 2002).
The general “rule” (as indicated in MPEP 2111.02 – Effect of Preamble) is that a patent claim preamble limits a claim when the preamble includes recitations limiting structure or when the preamble “breaths life and meaning into the claim.” Further, the Federal Circuit has held in at least one other case that a preamble may be limiting when the prosecution history indicates that the Applicant distinguished cited art on the basis of the citation in the preamble. Bass Pro Trademarks v. Cabela’s (Fed. Cir. 2007). Additionally, the preamble may be held as limiting if the specification or prosecution history of the subject application states that the recitation in the preamble is essential to the application. Conversely, if the preamble recitation is only a statement related to the purpose or use of the claimed invention, the preamble recitation is usually not considered to limit the patent claim.
Recitations Limiting Structure – Considered Limiting
Regarding the first limiting instance, the aforementioned citation to the MPEP states, “any terminology in the preamble that limits the structure of the claimed invention must be treated as a claim limitation. See, e.g., Corning Glass Works v. Sumitomo Elec. U.S.A., Inc., 868 F.2d 1251, 1257, 9 USPQ2d 1962, 1966 (Fed. Cir. 1989).” Accordingly, the preamble may be considered as limiting when a recitation in the preamble of the claim provides antecedent support to recitations in the main body of the claim.
Statements Reciting Purpose or Intended Use – Considered Not Limiting
The above citation to the MPEP additionally states, “the determination of whether preamble recitations are structural limitations or mere statements of purpose or use ‘can be resolved only on review of the entirety of the [record] to gain an understanding of what the inventors actually invented and intended to encompass by the claim.’ Corning Glass Works, 868 F.2d at 1257, 9 USPQ2d at 1966. If the body of a claim fully and intrinsically sets forth all of the limitations of the claimed invention, and the preamble merely states, for example, the purpose or intended use of the invention, rather than any distinct definition of any of the claimed invention’s limitations, then the preamble is not considered a limitation and is of no significance to claim construction. Pitney Bowes, Inc. v. Hewlett-Packard Co., 182 F.3d 1298, 1305, 51 USPQ2d 1161, 1165 (Fed. Cir. 1999).”
Preamble Drafting Strategies
A quick review of a number of patents reveals that there is no set or preferred method employed in drafting patent claim preambles. More specifically, while some patent claim preambles are drafted having a broad scope (e.g., “an apparatus comprising” or “a method comprising”), others are drafted with a more narrow scope with some specifics regarding the claimed invention, and possibly including language related to purpose or use. I prefer employing a mix of the aforementioned approaches, drafting claim preambles with varied scope, and including at least one independent claim having a preamble with a broad scope (e.g., “an apparatus comprising”) during the claim drafting process.
My overall view is that essential claim recitations should preferably be recited only in the main body of the claim. Failing to follow the aforementioned advice may result in unnecessary headaches during patent prosecution as many Examiners will not consider recitations included in the claim preamble as limitations of the claim. Additionally, as every term of a claim will be scrutinized during litigation, don’t include any language in the preamble which is unnecessary, as such language could be construed adversely against the Patentee.
Although there is persuasive authority as indicated above which describes various situations where a claim preamble is considered limiting, why risk having to assert this argument during patent prosecution, possibly generating unnecessary prosecution history estoppel and costs (monetary and time-related) for the client?