Conjunctions and/or Patent Claims

As the late Judge Rich famously wrote in 1990, “the name of the game is the claim.”  Extent of Protection and Interpretation of Claims—American Perspectives, 21 Int’l Rev. Indus. Prop. & Copyright L. 497, 499.  That is, a beautifully-written Detailed Description section of a patent’s specification is pointless if the patent’s claims are drafted in a manner that renders their infringement remote or even near impossible!  Okay, so why is this important?  Well, let’s start with one of the Patent Bar’s best-kept secrets: not all of us, despite having earned our USPTO registration numbers, are truly gifted at drafting claims!  With that said, we have taken a keen interest in studying the specific issue of how practitioners employ the conjunctions “and” and “or” in patent claims.

For those of us of a certain age, we can probably remember the School House Rock series of musically-animated, educational short films produced by the American Broadcasting Company from 1973 to 1985.  One of the more well-known titles of the series, “Conjunction Junction: What’s Your Function,” sought to teach grade school children how to use conjunctions to connect words, phrases and clauses.  (For older readers seeking some nostalgia, or younger readers wondering what we are talking about, the three-and-a-half minute film can be found here.)  Fast forward a decade or two, now that we are registered patent attorneys, is a refresher course in order?  More specifically, when writing patent claims, have we mastered when to use the conjunctions “and” and “or”?  Have we even recognized the difference in the two?

Illustrative of the importance of claim drafting, and the perils attached to the improper use of “or” within a claim, is Kustom Signals, Inc. v. Applied Concepts, Inc., 264 F. 3d 1326 (Fed. Cir. 2001).  In Kustom Signals, the Federal Circuit upheld a district court’s decision to grant summary judgment of non-infringement where the issue of infringement centered on the use of the conjunction “or.”   The case involved US Patent No. 5,528,246, entitled “Traffic Radar with Digital Signal Processing.” The ‘246 patent involved a traffic radar system that integrated digital signal processing for use by law enforcement and related applications. The ‘246 patent’s traffic radar system had two user-selectable modes of operation.

The claims at issue included representative independent Claim 1, which reads:

A method of processing Doppler return information in a traffic radar comprising the steps of:

(a) receiving Doppler return information containing at least one return signal derived from a target vehicle,

(b) presenting said Doppler return information as digital data,

(c) transforming said data into the frequency domain to provide a spectrum that includes frequency components corresponding to Doppler return signals contained in said information,

(d) storing said components in a memory,

(e) searching said components in memory for the component that meets preselected magnitude or frequency criteria, and

(f) indicating the speed of the target vehicle corresponding to the component that meets said criteria.

(Emphasis added.)


The U.S. District Court for the District of Kansas construed the word “or” in clause (e) of Claim 1 to mean “a choice between either one of two alternatives, but not both.”  This claim construction was significant because the accused device performed an analysis of both the strongest and fastest signals (i.e., a user could not select between a magnitude or frequency mode).  Therefore, because the accused device always performed both options, the court held that it did not infringe the ‘246 patent.

Before the Federal Circuit, the patentee argued that the correct interpretation of the term “or” should be consistent with its technical (computer) definition where a logical OR operator returns a true value when one or both operands are true (as distinguished from the AND logical operator, which returns a true value only when both operands are true).  After reviewing the specification and prosecution history of the ‘246 patent, however, the Federal Circuit found no indication that Kustom had used the word “or” in any manner other than its usual, common sense meaning as stating alternatives (i.e., there was no indication that the patentee had used “or” in a technical sense).

Then-Chief Judge Mayer dissented from the majority opinion because his reading of the specification and prosecution history of the ‘246 patent supported Kustom’s argument.  Judge Mayer understood the plain meaning of “or” to mean “either or both.”  His reasoning was that if a store owner says: “‘If it hails or snows today, we will close the store,’ then the owner will still close the store if it happens to hail and snow.”

Within a mere two weeks after Kustom Signals, the use of conjunctions once again played a controversial role in claim construction in Brown v. 3M, 265 F.3d 1349 (Fed. Cir. 2001).  At issue was Claim 16 of US Patent No. 5,852,824, entitled “Apparatus and Method for Processing Year-Date Data in Computer Systems.”  The ‘824 patent was directed to solving the Y2K two-digit year problem. (Was that really thirteen years ago!?  Time really flies when you’re drafting cases!)

Claim 16 of the ‘824 patent reads as follows:

An apparatus for processing year-date data in a computer system, the apparatus comprising:

a CPU; a bus coupled to the CPU;

a memory coupled to the bus;

a system clock coupled to the bus, wherein the system clock is set to an offset time wherein the offset time is a time other than the actual time;

at least one application program stored in the memory and being executed by the CPU;

at least one database file stored in the memory containing records with year-date  data with years being represented by at least one of two-digit, three-digit, or four-digit year-data representations; and

a mechanism for converting the year-date data representations in the database file to a two-digit year-date data representation.

(Emphasis added.)

The U.S. District Court for the District of Arizona interpreted the conjunction “or” in the penultimate clause of Claim 16 as meaning that the apparatus was capable of converting “only two-digit, only three-digit, only four-digit, or any combination of two-, three-, and four-digit date-data.”  Thus, the alleged infringer argued that the ‘824 patent was invalid as being anticipated by a prior U.S. patent that undisputedly taught remediation of two-digit year dates.  The patentee argued, however, that its system had the capability to act on a combination of two-, three-, and four-digit data that was not shown in the prior art reference (which was before the Examiner during prosecution).

The Federal Circuit declined to adopt the patentee’s rationale, instead holding that: “By claiming his invention in the alternative, [the patentee] has presented a claim for which infringement would lie whether or not there were also offset of three-digit or four-digit year dates. … [A]s written [Claim 16] would be literally infringed by a system that offsets year dates only in two-digit formats such as the [prior art] system.  Thus the district court correctly ruled [on summary judgment] that claim 16 was anticipated, and invalid for lack of novelty.”  Interestingly, then-Chief Judge Mayer dissented from the majority opinion once again, finding that “this is not a case of a species anticipating a genus, or of a combination claimed in the alternative.”

Before we begin to think that only the “or” conjunction is evil, the use of the conjunction “and” has also been problematic for patentees on occasion.  One such occasion presented itself in Joao v. Sleepy Hollow Bank, 348 F. Supp.2d 120 (S.D.N.Y. 2004), involving U.S. Patent No. 6,529,725, entitled “Transaction Security Apparatus and Method.”  The ‘725 patent discloses a device that provides an online alert if a transaction involving a person’s bank account is taking place, thereby giving the person an opportunity to decline any fraudulent transactions.

The ‘725 patent contained eight separate claims using the phrase “at least one of … and ….”  For example, Claims 108, 135, 138 and 164 of the ‘725 patent all included the following phrase:

“… wherein the limitation or restriction prohibits a withdrawal form at least one of a checking account, a savings account, and an automated teller account, or prohibits use of at least one of a checking account, a savings account, and an automated teller machine account.”

(Emphasis added.)

During the Markman hearing, the patentee argued that the disputed phrase, “at least one of … and …,” when combined with a list of items, means a single item from the list or any combination of items in the list.  Using the example phrase “at least one of A, B and C,” the patentee clarified that the phrase means “only A, or only B, or only C, or any combination of A, B and C.”  The alleged infringer, however, argued that the phrase means “one or more of A, one or more of B, and one or more of C,” (i.e., the net effect is the conjunctive, and not the disjunctive).


The district court found that if looking only to the plain meaning of the disputed phrase, the defendants would be correct “as a simple matter of good English grammar (admittedly, a lost art).”  Why?  Well, Strunk & White’s The Elements of Style (4th  ed. 2000) – the classic authority on English grammar – states that “[a]n article of a preposition applying to all the members of the series must either be used only before the first term or else be repeated before each term.”  In this particular case, however, interpreting the phrase according to proper English grammar would render the claims senseless.  In referring to the specification for guidance, the court found that the patentee “substitute[d] either the word ‘or’ or the phrase ‘and/or’ for the word ‘and’ every time they describe an embodiment of the claim.” Thus, the court accepted the patentee’s proposed interpretation and concluded that the only way the claims made sense was to substitute the word “or” for “and.”  The court, however, highlighted the fact that the change was made solely for the ‘725 patent in light of the claim language and specification and that the decision was to have “absolutely no precedential value for any other patent.”

The same patentee ran into the same problem some nine years later in Joao Bock Transaction Systems, LLC v. First National Bank, 2013 WL 3199981 (N.D. Ill., June 24, 2013), involving U.S. Patent No. 6,047,270, entitled “Apparatus and Method for Providing Account Security.”  Representative Claim 9 of the ‘270 patent reads:

A method for providing account security, comprising:

receiving one of a limitation and a restriction on usage of an electronic money account, wherein said one of a limitation and a restriction are received from an account holder;

storing said one of a limitation and a restriction;

processing a transaction on the electronic money account in conjunction with said one of a limitation and a restriction; and

generating a first signal, wherein said first signal contains information for one of approving and disapproving the transaction.

(Emphasis added.)

During the Markman hearing, the patentee, relying on Sleepy Hollow, argued that the disputed phrase, “one of A, B, and C means “only A or only B or only C.”  The defendant, however, argued that Sleepy Hollow was inapplicable because the term in that case was distinguishable (“at least one of A, B, and C” versus “one of A, B and C”), and that the phrase should be read according to its plain meaning.  Thus, the defendant proffered that “one of A, B, and C” means “one A, one B and one C.”  While recognizing that English grammar demanded defendant’s interpretation of the disputed phrase, the court reasoned that such “plain meaning” would render the claims senseless.  Thus, the court concluded the phrase, “one ofand …” means “‘one or more of the items in the list’ or ‘either or both of the items in the list.’” Like Sleepy Hollow, the court found guidance in the specification of the patent-in-suit: “It is clear from the specification that Joao Bock intended the words ‘limitation’ and ‘restriction’ to be used interchangeably. Particularly persuasive is the fact that the two words are separated frequently by the article ‘and/or.’”

Given the problems that may arise when a practitioner uses “and” or “or”, is it safe just to forget grammar, hedge one’s bets and simply use “and/or” in the hopes that a district court (and even maybe the Federal Circuit) will save the day!?  After all, District Court Judge Colleen McMahon stated it nicely:

“One of the things I have learned in my brief but intensive introduction to patent law is that plain English grammar and syntax are not always endorsed by either patent examiners or courts interpreting patents. … So I accept the proposition that it is perfectly proper to ignore English grammar and syntax when interpreting patent claim language – at least, when context renders a different reading more sensible.”

Sleepy Hollow at **11-12.  This is, no doubt, an interesting question.  We think the right answer is probably “no”!

In the law in general, the use of the conjunction/disjunction (i.e., “and/or” and even “or/and”) has been widely criticized as a “freakish fad,” an “accuracy-destroying symbol,” and “meaningless.”  A Wisconsin Supreme Court opinion referred to the “and/or” construction as “the child of a brain of someone too lazy or too dull to know what he did mean.”  Employers Mutual Liability Insurance Co. v. Tollefson, 263 N.W. 376, 377 (1935).  Moreover, the Florida Supreme Court has held that use of “and/or” results in a nullity, stating:

We take our position with that distinguished company of lawyers who have condemned its use. It is one of those inexcusable barbarisms which were sired by indolence and damned by indifference, and has no more place in legal terminology than the vernacular of Uncle Remus has in Holy Writ. I am unable to divine how such senseless jargon becomes current. The coiner of it certainly had no appreciation for terse and concise law English.

Cochrane v. Fla. E. Coast Rwy. Co., 145 So. 217 (1932).  Wow!

So have many patent practitioners been guilty of such “inexcusable barbarisms”?  To be sure, we looked at the USPTO database and found a not insignificant amount of use of the “and/or” construct – about 5% of issued utility patents since 1976 and about 10% of published utility applications since 2001!  We even found a surprising number of uses of the “or/and” construct. (See the accompanying infographic.  Admittedly, some – perhaps small – percentage of these claims probably refer to compound logic gates, but you get the point!)

When we were first-year associates, while learning the art of claims drafting from patent attorneys whose USPTO registration numbers were in the 20,000’s, we learned never to use “or” in a patent claim.  Rather, we were told to always use “and,” really think about what we were claiming (e.g., “wherein the device comprises at least one of: A, B, C and D,” versus “wherein the device comprises at least one or more of: A, B, C and D,” etc.), and to consider drafting separate claims to cover alternatives rather than simply presenting a list of items joined by the conjunction “or.”  Put in Judge Mayer’s words, perhaps the lesson to be learned from the foregoing cited cases is – when possible – not to use alternative language (i.e., “or”) but rather write entirely separate claims, one claim dealing with “hail” and a separate claim dealing with “snow”!

Judge James Randall Durfee observed over 45 years ago that: “Things are not made for the sake of words, but words for things.” Autogiro Co. of Am. v. United States, 384 F.2d 391, 397 (Ct. Cl. 1967).  So, members of the patent bar, be reminded to pick your words (especially conjunctions) wisely, know the function of each of said chosen words, and happy claims drafting.



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Join the Discussion

9 comments so far.

  • [Avatar for Pro Se]
    Pro Se
    October 20, 2013 02:35 am

    Place a $20, a $50, and $100 in front of someone and ask them “take at least one of a $20, $50, or $100” nothing stops the person from taking the full $170, unless they are told “take only one of a $20, $50, or $100”..

  • [Avatar for Pro Se]
    Pro Se
    October 20, 2013 02:29 am

    If I ever had to argue this in court, I would ask the judge:

    “If a man got stuck on a deserted island with over 100 beautiful women and was told to pick at least one woman to live forever with, would that instruction limit him to only picking 1 or all 100?

  • [Avatar for Pro Se]
    Pro Se
    October 20, 2013 02:19 am

    Here is the danger of using “and” to somehow really represent “or” in a claim (which by just common sense is weird):

    What if one day a judge constructs by the real meaning of “at least one of A, B, and C” as meaning:
    Combinations of A+C or B+C are the only possible ways to infringe?

    Outside of claiming strict Markush style claims, I’m sticking with “or” in structures where it’s engineering accurate.

  • [Avatar for Anon]
    October 19, 2013 07:04 am


    I do not think the difference you point out in 5 is the aim of the discussion.

    Your first phrase yields at least one of each, while your second yields at least one of the one or at least one of the other – what is being aimed for is at least one of ‘a’ or at least one of ‘b’ without necessarily distinguishing between ‘a’ or ”b’ and without having at least one of each ‘a’ and ‘b.’

    A further point is that judges will throw out grammar lessons in claim constructions on occasion.

    I will (half-jokingly) nominate the (somewhat) wordy – quadrupling down on the ‘or’:
    “at least one of A, B, or C, or at least one of any combination of A, B or C (with each species in singular or multiple possibility)”.

  • [Avatar for Sid Bennett]
    Sid Bennett
    October 18, 2013 10:54 am

    This article is way out of date. The FedCkt in Superguide v Tivo gave the grammar lesson that is controlling.
    For example, “at least one one of a and b” is very different than “at least one of a or b.”

  • [Avatar for Ray]
    October 18, 2013 08:32 am

    @Solo Inventor: I like your “at least one from the group…” construct. As for dropping the “and”, I guess Judge McMahon said it best: “[I]t is perfectly proper to ignore English grammar and syntax when interpreting patent claim language.” 🙂

  • [Avatar for Solo Inventor]
    Solo Inventor
    October 17, 2013 09:50 pm

    What about dropping the risky word “and” entirely; such that:

    “at least one of A, B, C”

    Not proper English; but perhaps safer claim drafting.

    Personally, I like: “at least one from the group consisting (or comprising, depending on what you’re trying to claim) A, B, and C.”

  • [Avatar for Ray]
    October 17, 2013 03:27 pm

    I think the point is that “at least one of A, B and C” is the preferred syntax, so long as the specification is clear that it means “either A, B, C or any combination of A, B and C.”

  • [Avatar for Helen]
    October 17, 2013 11:39 am

    Wow! I am getting so confused here. When learning patent drafting, I was thought by my mentor to use the expression “at least one of A, B and C” when I wanted to say “A, B or C” with the “or” being non-exclusive. This is because “A, B or C” would most probably be construed at being exclusive. Then, if, according to Sleepy Hollow Bank, “at least one of A, B and C” means “at least one of A, at least one of B and at least one of C”, what expression should I use if want I want to claim is “either A, B, C or any combination of A, B and C”?

    I thought of “at least one of A, B or C” but then, if we follow Sleepy Hollow Bank, this should be construed as “at least one of A, at least one of B or at least one of C”. This is again different form “either A, B, C or any combination of A, B and C”.

    It seems that a number of patent claims that I have drafted in the past may not be construed in the US as I intended them to be…