An New (Old) Perspective on Claim Construction

In Century Electric Co. v. Westinghouse Electric & Mfg. Co., 191 F. 350 (8th Cir. 1911), the Eighth Circuit had in interesting perspective on claim construction. The Eighth Circuit said that a patent “is a contract made by the acceptance by the government of the offer which the patentee by his application makes to disclose his invention, in consideration that the United States will secure to him the exclusive use and sale of it for 17 years,”

The Court continued:

The offer embodied in the application becomes the specification of his patent, if his offer is accepted, and with his claims evidences the terms of the agreement. Such an agreement is interpreted by the same rules that determine other contracts. The court, should, as far as possible, place itself in the situation of the parties when they made their agreement and then seek to ascertain from the terms of their contract, in the light of the circumstances then surrounding them, what their intention was.

This intention should be deduced from the entire contract and not from any part of it or without any part of it, because they did not agree to it, or to any part of it, without every other part of it. The specification which forms a part of the same application as the claims must be read and interpreted with them, not for the purpose of limiting, or of contracting, or of expanding, the latter, but for the purpose of ascertaining from the entire agreement, of which each is a part, the actual intention of the parties and that intention when ascertained should prevail over the dry words and inapt expressions of the contract evidenced by the patent, its specification and claims.

Modern claim construction seem more rule-bound, and might be improved if animated by the purpose to determine what the inventor invented, not what the claims literally say.

Earth Day 2023

Earth Day has been the inspiration for numerous environmental initiatives, including the EPA. and it has also been the motivation for many inventions:

U.S. Patent No. 5505114 protects a Simulated Musical Rainmaker, which the patent describes as the “perfect toy to celebrate Earth Day.

U.S. Patent No. D407127 protects the ornamental design for a baseball. which can include an Earth Day logo:

U.S. Patent No. 10,712,723 on a System and Method of Compiling and Organizing Power Consumption Data and Converting such Data into One or More User Actionable Formats, suggests that the invention “could include real-time feedback as events like Earth Day occur, to demonstrate the en-masse savings and conservation, the environmental impact, etc.”

U.S. Patent No. 9336540 on a Method and System for use of Game for Charity Donations suggests that it can be used to raise funds for Earth Day:

On this this 54th Earth Day, the world has accomplished a lot, but there is much more to be done; hopefully with creativity and inventiveness we can continue to make progress.numer

Computer-Readable Recording Medium Is Not a Transitory Medium

In Sequoia Technology, LLC v. Dell, Inc., [2021-2263, 2021-2264, 2021-2265, 2021-2266] (April 12, 2022), the Federal Circuit disagreed with the district court’s claim construction for “computer-readable recording medium,” and thus reverses the district court’s ineligibility determination under 35 U.S.C. § 101. In addition, the Federal Circuit agreed with the district court’s claim construction for “disk partition” and “logical volume,” and thus affirmed the district court’s noninfringement determination.

The magistrate judge adopted and construed “computer-readable recording medium” to include transitory media (i.e., signals or waves),base upon the specification, which discusses “computer readable medium” as “including” a list of items—none of which are transitory— and interpreted that language as leaving the door open for media that could be transitory.

The Federal Circuit noted at the outset that the claim language does not actually recite a “computer-readable medium” or CRM. Instead, it more narrowly recites “computer-readable recording medium storing instructions. The Court said that a person of ordinary skill would not understand transitory signals, such as carrier waves, to record or store instructions in memory systems. This is because transitory signals, by their very nature, are fleeting and do not persist over time. Other elements in the claim confirm that the claim is directed to hardware as opposed to transitory waves or signals.  The Federal Circuit found that the claim language demonstrates that claim 8 is not directed to a transient signal, but rather to a non-transient storage medium.

The Federal Circuit then turned to the specification, which discloses only non-transitory media.  The Court said the use of a term denoting a nonexhaustive list does not eviscerate our obligation to construe terms in the context of the entire patent. The context

here makes clear that the term “computer-readable recording medium” cannot encompass transitory media.

The Federal Circuit declared that its decision rests solely on the intrinsic evidence, and that it was unpersuaded by arguments to the contrary, which rest on extrinsic evidence.  The Court further noted that not only was this extrinsic evidence was inconsistent with the intrinsic evidence and also based on different express definitions of CRM in patent specifications directed to different inventions.

The Federal Circuit disagreed with the district court’s claim construction and, consequently, reversed the district court’s holding that claims 8–10 are ineligible under § 101.

How Many?

An often critical issue in determining patent infringement is how many of a specified claim element are required by the claim. This issue can arise in a variety of ways:

A or An

The general rule is that “a” or “an” means one or more. In KCJ Corp. v. Kinetic Concepts, Inc., 223 F.3d 1351 (Fed. Cir. 2000), the Federal Circuit observed:

an indefinite article “a” or “an” in patent parlance carries the meaning of “one or more” in open-ended claims containing the transitional phrase “comprising.” … Unless the claim is specific as to the number of elements, the article “a” receives a singular interpretation only in rare circumstances when the patentee evinces a clear intent to so limit the article. … Under this conventional rule, the claim limitation “a,” without more, requires at least one.

See, also  Baldwin Graphic Sys., Inc. v. Siebert, Inc., 512 F.3d 1338 (Fed. Cir. 2008).

However, the Federal Circuit indicated that there are situations where “a” or “an” can mean “only one.” See, for example, Harari v. Lee, 656 F.3d 1331 (Fed. Cir. 2011), and Insituform Techs., Inc. v. CAT Contr., Inc., 99 F.3d 1098, 1106 (Fed. Cir. 1996).

How can the careful prosecutor ensure the interpretation he or she wants? One way is to provide a definition in the specification. Thousands of patents do.

  1.  As used herein, “a” or “an” or “the” can mean one or more than one. For example, “a” widget can mean one widget or a plurality of widgets. See, e.g., U.S. Patent No. 1082263.9
  2. As used herein, “a” or “an” may mean one or more than one. See, e.g., U.S. Patent No. 10525082.
  3. Unless otherwise indicated or the context suggests otherwise, as used herein, “a” or “an” means “at least one” or “one or more.” See, e.g., U.S. Patent No. 10546223.
  4.  As used herein, “a” or “an” means “at least one” or “one or more” unless otherwise indicated. See, e.g., U.S. Patent No.7465758.
  5. As used herein, “a” or “an” means at least one, unless clearly indicated otherwise. See, e.g., U.S. Patent No.11275080.
  6. As used herein, “a” or “an” means one or more unless otherwise specified. See, e.g., U.S. Patent No. 9540312.

A problem with definitions is that the prosecutor has to commit to a meaning, and do so by the time of filing. In the examples above definitions #1 and #2 aren’t really definitions at all – they merely state a possible meaning. No options are foreclosed, buy no certainty is achieved. Definitions #3 expresses a preference, but there is still some uncertainty. Definitions #4 – #6 provides a definition that is only superseded by an “indication” or a “specification” otherwise.

More certainty is obtained by specifying “one” or “at least one” when the element is described and claimed.


The simple word “or” has multiple, inconsistent meanings. In some contexts, “or” can express exclusive alternatives. In these cases “A or B” means either A and not B, or B and not A. See, Kustom Signals, Inc. v. Applied Concepts, 264 F.3d. 1326 (Fed. Cir. 2001). In other contexts, “or” can express non-exclusive alternatives. In these cases “A or B” means just A, A and B, or just B. Brown v. 3M, 265 F.3d 1349 (Fed. Cir. 2001).

As discussed above, definitions can help provide some certainty. There are numerous examples:

  1. The term “or” as used in this disclosure is to be understood to refer a logically inclusive or not a logically exclusive or, where for example the logical phrase (if A or B) is satisfied when A is present, when B is present or where both A and B are present (contrary to the logically exclusive or where when A and B are present the if statement is not satisfied). See, e.g., U.S. Patent No. 9747910.
  2. As used herein, “or” is understood to mean “inclusively or,” i.e., the inclusion of at least one, but including more than one, of a number or list of elements. In contrast, the term “exclusively or” refers to the inclusion of exactly one element of a number or list of elements. See, e.g., U.S. Patent No. 10639598.

The examples above provide definitions of an inclusive “or,” but also provide a template of how to define an exclusive “or.”

Alternatively, the careful prosecutor can be more precise in the specification and claims. One way is to claim “A and/or B” for an inclusive “or”, and “either A or B” for an exclusive “or.”


“And” has also caused problems for patent owners.  In Super Guide Corp. v. DirecTV Enters., Inc., 358 F.3d 870, 885-86 (Fed. Cir. 2004), the patent owner and the accused infringer disagreed over the effect of “and” in the claim limitation “first means for storing at least one of a desired program start time, a desired program end time, a desired program service, and a desired program type.” The patent owner argued that this language required at least one of any of the four list categories. The accused infringer argued that this language required at least one from each of the four listed categories. The Federal Circuit agreed with the accused infringer, noting that the phrase “at least one of” preceded a series of categories of criteria, and the patentee used the term “and” to separate the categories of criteria, which connotes a conjunctive list. The Federal Circuit cited William Strunk, Jr. & E.B. White, The Elements of Style 27 (4th ed. 2000). The TTAB has reached a similar result in Ex Parte Jung, Appeal 2016-008290 at 2 (P.T.A.B. Mar. 22, 2017).

Thus when enumerating a list, the careful prosecutor must be mindful choosing whether to join the list with “and” or “or”


If “or” and “and” can cause problems, it would seem that “and/or” can likewise cause problems. As Wikipedia notes, “and/or” has come under criticism in the courts. Judges have called it a “freakish fad”, an “accuracy-destroying symbol”, and “meaningless”. In Ex Parte Gross, Application No. 11/565,411, the Examiner rejected claim 1 as indefinite based upon the use of “and/or.” However, the PTAB reversed – finding that “A and/or B” does have a meaning and that meaning is A alone, B alone, or A and B together. The Board noted the “preferred verbiage” should be more simply “at least one of A and B.”

While not popular with legal purists, “and/or” may be the best choice to get the intended claim scope.

Protection for Non-Literal Portions of Code Filtered Out by the Abstraction-Filtration-Comparison Test

SAS Institute, Inc., v. World Programming Limited, [2021-1542] (April 6, 2023), the Federal Circuit affirmed the district court’s determination that SAS failed to establish the copyrightability of its software.

SAS creates and sells a suite of software used for data access, data management, data analysis, and data presentation.  Users of the SAS System write commands in a SAS programming language .  World Programming Limited (“WPL”) created a competing system that uses the SAS programming language to allow users to complete analytics tasks.

Whether a particular component or element of a program is protected by a copyright depends on whether it qualifies as an expression of an idea, rather than the idea itself.  Other doctrines of copyright law detail what elements are not protectable, including scènes à faire elements, material in the public domain, factual material, and elements under the merger doctrine.  The literal elements of computer programs, for example: source and object codes, can be the subject of copyright protection, and as a general matter, and to varying degrees, copyright protection can extend beyond literal elements to nonliteral elements.

The appeal involves only nonliteral elements of the SAS System, i.e., those aspects that are not reduced to written code. These elements include the program architecture, structure, sequence and organization, operational modules, and user interface.  The Federal Circuit explained that using a literary novel as an analogy, the novel’s written words would be the literal elements (e.g., code) and the organization of the chapters, characters, and plot would be the nonliteral elements.  The Federal Circuit observed, that as one moves away from the literal elements to more general levels of a computer program, it becomes “more difficult” to distinguish between unprotectible ideas, processes, methods or functions, on the one hand, and copyrightable expression, on the other.

The Federal Circuit observed that the Second, Fifth, and Tenth Circuits, have adopted the abstraction-filtration comparison test, or method, to determine the scope of copyright protection for computer programs, including their nonliteral elements.  The abstraction-filtration-comparison method involves three steps: First, the court breaks down the allegedly infringed program into its constituent structural parts—abstraction. This step helps a court separate ideas and processes from expression and eliminate those portions of the work that are not eligible for protection.  Second, the court sifts out all non-protectable material—filtration.  The court examines the structural components at each level of abstraction” and “defining the scope of plaintiff’s copyright”.  Third, the trier of fact compares any remaining “core of protectable expression” with the allegedly infringing program to determine if there is in fact a substantial similarity—comparison. SAS contended that the district court legally erred in its application of the abstraction-filtration-comparison test.  The Federal Circuit rejected SAS’ argument that it satisfied its evidentiary burden once it demonstrated that the SAS System was covered by registered copyrights. The Federal Circuit also rejected SAS argument that the district court erred when it shifted the burden to SAS to establish that its asserted elements are protected by copyright law, noting that any plaintiff has to respond to any proof advanced by defendant.

“A Processor” Can Mean More Than One Processor, But At Least One of Multiple Processors Has to be Capable of Performing All of “Said” Processor’s Functions

In Salazar v. AT&T Mobility LLC, [2021-2320, 2021-2376] (April 5, 2023), the Federal Circuit affirmed judgment of noninfringement of U.S. Patent No. 5,802,467 describing technology for wireless and wired communications.

Claim 1 of the ‘467 patent required “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.”  The district court construed the court construed “a microprocessor” to mean one microprocessor.”

On appeal, Salazar argued that the court should have interpreted a microprocessor” to require one or more microprocessors, any one of which may be capable of performing each of the “generating,” “creating,” and “retrieving” functions recited in the claims.

The Federal Circuit explained that the indefinite article “a” means “‘one or more’ in open-ended claims containing the transitional phrase ‘comprising.’” The Court said an 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.”   The Federal Circuit further explained that the use of the term “said” indicates that this portion of the claim limitation is a reference back to the previously claimed” term.  The claim term “said” is an “anaphoric phrase, referring to the initial antecedent phrase”. 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.”

The Federal Circuit reviewed prior cases interpreting “a” and noted in particular In re Varma, 816

F.3d 1352 (Fed. Cir. 2016), which the district court had explained that the claim term provided certain functions that the “said microprocessor” must be “necessarily configured to perform as well as the structural relationship between ‘said microprocessor’ and other structural elements.”  Thus, the district court reasoned, “at least one microprocessor must satisfy all the functional (and relational) limitations recited for ‘said microprocessor.’ On appeal, Salazar’s argued that a correct claim construction would encompass one microprocessor capable of performing one claimed function and another microprocessor capable of performing a different claimed function, even if no one microprocessor could perform all of the recited functions.  The Federal Circuit rejected this argument, agreeing with the district court that while the claim term “a microprocessor” does not require there be only one microprocessor, the subsequent limitations referring back to “said microprocessor” require that at least one microprocessor be capable of performing each of the claimed functions, which the Court said was “entirely consistent” with it precedents. The Court noted that, as it stated in Varma, for 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.