By Christine Norris, Michelle E. O’Brien, and Tom Irving
The simple one letter word, “a” continues to spawn significant ambiguity in U.S. patent claim construction. We have seen the Federal Circuit interpret the term “a” open-endedly to leave room for plural claim elements (one or more), or as inferring a singular claim element (one). The Federal Circuit in Salazar v. AT&T Mobility LLC, No. 21-2320; -2376 (Fed. Cir. Apr. 5, 2023) provides further guidance on how to construe “said” term that some may argue is clarifying, while others may argue simply adds to the confusion.
The claim terms at issue in claim 1 and multiple other asserted claims of Salazar’s U.S. Patent No. 5,802,467 patent reads:
- A communications, command, control and sensing system for communicating with a plurality of external devices comprising:
a microprocessor for generating a plurality of control signals used to operate said system, said microprocessor creating a plurality of reprogrammable communication protocols, for transmission to said external devices wherein each communication protocol includes a command code set that defines the signals that are employed to communicate with each one of said external devices;
a memory device coupled to said microprocessor configured to store a plurality of parameter sets retrieved by said microprocessor so as to recreate a desired command code set….
The U.S. District Court for the Eastern District of Texas construed the claim term “a microprocessor” as requiring at least one microprocessor that is capable of performing all of the recited functional (and relational) limitations recited for “said microprocessor,” such as the recited “creating,” “retrieving,” and “generating” functions. See id. at 4-5.
The Federal Circuit affirmed the district court in its de novo review, holding that Salazar’s claims require a singular element—“a” microprocessor—to be capable of performing all of the recited functionality. See id. at 11. Appellant argued that the claims should be construed as reciting “one or more microprocessor(s)” and any subsequent reference to “said microprocessor” with a recited function should be construed as referring to “any one of the one or more” microprocessors, but the court declined to do so. Id. (emphasis added). In coming to this conclusion, the court compared and contrasted the following precedential decisions which addressed the question of whether “a” means “one or more” or “one and only one.”
The General Rule: “A” Means “One or More”
To start, the Federal Circuit made clear that “the indefinite article ‘a’ [generally] means ‘one or more’ in open-ended claims containing the transitional phrase ‘comprising.’” Id. at 7 (emphasis added) (citing Convolve, Inc. v. Compaq Computer Corp., 812 F.3d 1313, 1321 (Fed. Cir. 2016) (quoting KCJ Corp. v. Kinetic Concepts, Inc., 223 F.3d 1351, 1356 (Fed. Cir. 2000))). The court also explained that “the subsequent use of [the] definite article[]… ‘said’ in a claim to refer back to the same claim term does not change the general plural rule, but simply reinvokes that non-singular meaning” of the indefinite article “a.” Id. at 7 (citing Baldwin Graphic Sys., Inc. v. Siebert, Inc., 512 F.3d 1338, 1342 (Fed. Cir. 2008)).
The court provided the following example claim where “a pre-soaked fabric roll” means “one or more pre-soaked fabric rolls” when providing antecedent basis for the term “said”:
- A pre-packaged, pre-soaked cleaning system for use to clean the cylinder of printing machines comprising in combination:
(1) a pre-soaked fabric roll saturated to equilibrium with cleaning solvent disposed around a core, said fabric roll having a sealed sleeve which can be opened or removed from said fabric roll for use of said fabric roll, … and said system including
(2) means for locating said fabric roll adjacent to and operatively associated with a cylinder to be cleaned.
See id. at 7-8 (emphases added) (citing Baldwin, 512 F.3d at 1340).
The Exception: “A” Means “One and Only One”
The Federal Circuit, however, made clear that “Baldwin … does not set a hard and fast rule that ‘a’ always means one or more than one.” Id. at pp. 7-9 (citing Baldwin, 512 F.3d at 1342-43). The court stipulated that “[a]n exception to the general rule that ‘a’ … means more than one only arises where the language of the claims themselves, the specification, or the prosecution history necessitate a departure from the rule.” Id. (emphasis added). The court then summarized several precedential claim construction decisions that necessitated a departure from the rule, leading to a finding that “a” meant one and only one:
- Claim language at issue in Harari v. Lee, 656 F.3d 1331 (Fed. Cir. 2011):
A method of treating at least one erased EEprom cell, comprising:
[(1)] accessing a number of control gates and accessing a bit line, thereby activating a number of memory cells,…; [and]
[(2)] subsequent to accessing said bit line, sensing the presence of at least one activated cell from said number of memory cells.
The court in Harari held that given the “plain language of the claim”… “the correct and only reasonable construction of the claim terms ‘a bit line’ and ‘said bit line’ … requires that a single bit line activates multiple memory cells.” Salazar, slip op. at 9 (emphases added) (citing Harari, 656 F.3d at 1342).
- Claim language at issue in Convolve, Inc. v. Compaq Computer Corp., 812 F.3d 1313 (Fed. Cir. 2016):
1. User interface for operatively working with a processor to affect operation of a data storage device, the user interface comprising … means for causing the processor to output commands to the data storage device … to reduce selected unwanted frequencies from a plurality of frequencies in accordance with the altered settings in the user interface.
9. Apparatus for controlling operation of a data storage device, the apparatus comprising: … a processor which executes the process steps so as (i)….
The Federal Circuit in Convolve reasoned that the body of claim 1 recites “‘the processor,’ and referring back to the ‘a processor’ recited in [the] preamble, supports a conclusion that the recited user interface is ‘operatively working with’ the same processor to perform all of the recited steps,” thus requiring one “processor associated with the user interface to issue the shaped commands of the claims.” Salazar, slip op. at 9-10 (emphasis added) (citing Convolve, 812 F.3d at 1321).
- Claim language at issue in Varma v. Int’l Bus. Machs. Corp., 816 F.3d 1352 (Fed. Cir. 2016):
22. A system for providing statistical analysis of investment information over an information network comprising: … a plurality of processors collectively arranged to perform a parallel processing computation, wherein the plurality of processors is adapted to:
receive a statistical analysis request corresponding to two or more selected investments;
based upon investment data pertaining to the two or more selected investments, ….
The Federal Circuit explained that the claimed “system must be adapted to receive a [single] request that itself corresponds to at least two investments.” Salazar, slip op. at 10-11 (emphasis added) (citing Varma, 816 F.3d at 1362-63).
Salazar’s claims
Thus, relying on the aforementioned cases, the Federal Circuit concluded while Salazar’s claims may comprise “one or more microprocessors,” at least one of the microprocessors must be configured to perform all of the “creating, retrieving, and generating functions.” Id.
The court compared Salazar’s claims to the claims in Varma and claims 1, 3, and 4 in Convolve, which required that a “singular element” perform all of the recited functions. The Federal Circuit, quoting itself in Varma, analogized that “[f]or a dog owner to have ‘a dog that rolls over and fetches sticks,’ it does not suffice that he have two dogs, each able to perform just one of the tasks.” Id. at 12 (quoting Varma, 816 F.3d at 1363). In contrast, Convolve’s claim 9 “had no subsequent reference to ‘the’ or ‘said’ processor, and thus did not require a single processor.” Id.
Takeaways
As demonstrated time and again, construing “a” to mean “one or more” or “at least one” is not a hard and fast rule. Indeed, as noted in Judge Mayer’s and Judge Newman’s dissent in Phillips almost 20 years ago, purely legal claim construction rules are difficult to make and fairly enforce, as questions, e.g., regarding the skill of one of ordinary skill in the art, the state of the art at the time of invention, or the meaning of patent terms, which are critical to the correct interpretation of a claim, are inherently factual. See Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Circ. 2004). Thus, the judges aptly noted that “[f]act-bound resolutions cannot be made uniform through appellate review, de novo or otherwise.” Id. at 1331 (quoting Mars Steel Corp. v. Cont’l Bank N.A., 880 F.2d 928, 936 (7th Cir. 1989)). Baldwin, Harani, and now Salazar keenly acknowledge this problem when holding that an exception to the general rule for “a” exists only when “the language of the claims themselves, the specification, or the prosecution history necessitate a departure from the rule” to provide for “the correct and only reasonable construction.” Salazar, slip op. at 7, 9 (emphasis added) (quoting Baldwin Graphic Sys., 512 F.3d at 1343; Harari, 656 F.3d at 1342).
Practitioners should keep these warnings in mind when drafting claims to avoid narrow judicial claim constructions that may open the door for easy, non-infringing design arounds. One option would be to utilize the phrases “at least one” or “one or more” instead of “a” or “an,” thinking carefully whether the context of the claim, as interpreted in Phillips to require consideration of the “intrinsic evidence,” i.e., the specification, the claim language itself, and the prosecution history, evidences that “a” means one and only one or one or more.
Similarly, practitioners should be careful when using the term “said,” and consider whether references back to the original term change the plurality, or singularity, of the term. Special care should be taken when “said” is preceded or followed by multiple steps, functions, or discrete limitations to the term, or where the term “said” is used repeatedly in the same claim to refer to the same term.
In other words, it might behoove an indulgent child approaching the Federal Circuit bench to request “a cookie jar” comprising “at least one cookie,” if the child would potentially desire more than one cookie. However, the child’s parent should request “a cookie jar” comprising “one and only one cookie” if the parent wants to limit their child’s sugar intake.