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35 USC § 112(b) requires that the specification of a patent “conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention". The failure of a claim to particularly point out and distinctly claim the inventive subject matter, as required by 35 USC 112(b), is frequently referred to as indefiniteness, and will result in the claim being held invalid.

In Nautilus, Inc. v. Biosig Instruments, Inc., the U.S. Supreme Court held that:

“a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.”

One word that practitioners should avoid when drafting claims is "can." Although the word itself is not complicated, it is frequently rejected by U.S. Patent Examiners as being indefinite. For example, if a claim intends to show the capabilities of a device, it might say "the device can perform the function of…" A common reaction by the Examiner is that such language is indefinite because "even if the device can perform the function, there may be situations when the device does not perform the function." Although I have never understood the logic of this type of rejection, it is fortunately easy to avoid that rejection by using words that Examiners are not trained to reject. For example, if the language was changed to "the device is configured to perform the function of…," the Examiner will almost always accept it, even though, in my mind, the meaning is identical.

There are a few recent cases that illustrate problems with using functional language to define the capabilities of structure in U.S. claims.

Ex Parte Breed

In Ex parte Breed, the Patent Trial and Appeal Board (Board) considered the definiteness of a claim in S.N. 12/020,684. The claim at issue was directed to a driving condition monitoring system for a vehicle on a roadway. The last paragraph recited:

“whereby roadway conditions from multiple roadways can be obtained and processed at the remote facility via multiple vehicles travelling on different roadways or different portions of the same roadway and can be directed from the remote facility to other vehicles on the roadway or roadways from which the information is obtained.”

During examination, the Examiner rejected claim 1 as indefinite. The Examiner stated that it is not clear if Appellants intended the "can be" claim limitation to be optional or that the phrase should be interpreted as a definite statement. The Board found that:

“The verb form of the word "can" carries multiple meanings in the English language. It can be used to indicate a physical ability or some other specified capability.  It can also be used to indicate a possibility or probability.”

The Board concluded that:

“We agree with the Examiner that "can be" is indefinite, because it is susceptible to more than one plausible construction. It is unclear whether the limitation refers to a capability that is required to be present in the invention or whether it refers to a system capability that is a mere possibility that is not required.  In other words, it is unclear whether a vehicle monitoring system can practice the invention of claim 1 by satisfying all of the other limitations of claim 1, without necessarily being required to possess the capability to obtain and process roadway conditions at a remote facility or to direct information from a remote facility to other vehicles on a roadway.”

In re Giannelli

In In re Giannelli, the Court of Appeals reviewed the patentability of a device claim:

1. A row exercise machine comprising an input assembly including a first handle portion adapted to be moved from a first position to a second position by a pulling force exerted by a user on the first handle portion in a rowing motion, the input assembly defining a substantially linear path for the first handle portion from the first position to the second position.

The USPTO Patent Trial and Appeal Board (Board) construed the phrase "adapted to be" as meaning "can" or "capable of." In other words, the Board construed the claim as merely requiring that the first handle portion can "be moved from a first position to a second position…in a rowing motion". In affirming the Examiner's rejection, the Board found that the applied prior art had a handle that could in fact be moved from a first position to a second position in a rowing motion.

In reality, the prior art had a handle that was designed to be pushed, not pulled. In reversing the Board's decision, the Court of Appeals found that the phrase "adapted to" is frequently used to mean "made to," "designed to" or "configured to." Based on this analysis, the Court stated that "the relevant question before the Board was whether the apparatus described in the [prior art] was “made to,” “designed to” or “configured to" allow the user to perform a rowing exercise by pulling on the handles as claimed. Finding that the prior art structure was not so designed, the Court reversed the rejection.

The Giannelli decision illustrates the subtle, but very important difference between defining a structure that "can" perform a recited function versus a structure that is "adapted to", "made to," "designed to," or "configured to" perform a recited function.

As a cautionary note, the Court did explain that:

“Although the phrase can also mean “‘capable of’ or ‘suitable for,’” id., here the written description makes clear that “adapted to,” as used in the ’261 application, has a narrower meaning, viz., that the claimed machine is designed or constructed to be used as a rowing machine whereby a pulling force is exerted on the handles.”

Accordingly, it is important to be sure that the specification, as well as the claim language, supports the intended meaning. The decision also points out that "adapted to" may have a broader meaning than intended, and thus may encompass "can." Accordingly, it is preferable to use a term such as is "made to," "designed to" or "configured to" rather than the broader term "can."

Medgraph, Inc. v. Medtronic, Inc.

Although the issue with the claim did not arise from the word "can," the case highlights the importance in being careful when describing the capabilities of a claimed structure.

Medgraph owns patents directed to a method for improving and facilitating diagnosis and treatment of patients, whereby data relating to medically-important variables, such as blood sugar levels, for example, are uploaded to a computer and transmitted to a central storage device. The data can then be accessed remotely by medical professionals treating the patient. Medgraph filed a suit for infringement of the '124 patent against Medtronic

Claim 16 recites (in part):

“A system for improving and facilitating diagnosis and treatment of patients having medical conditions requiring long-term profiles of at least one predetermined medically important variable, comprising...

means for inputting said at least one predetermined medically important variable as raw data into a primary computer comprising software and hardware enabling said primary computer system to operate as at least one of a web server, a dial-up host, a network server, and a telephone answering and data collection device whereby raw data can be communicated from a remote computer proximate a patient comprising an ordinary general purpose personal computer and from an ordinary telephone wherein data is transmitted as one of spoken data and touch-tone data;..

means to transmit said requested data in the form of at least one of a chart and graph generated from said data from said primary computer to a remote computer proximate said practitioner whereby said primary computer is one of a web server, a dial-up host, and a network server and means to transmit said requested data by facsimile through a faxmodem integrated with said primary computer... (Emphasis added).”

An issue on appeal before the U.S. Court of Appeals for the Federal Circuit was the definiteness of claim 16. The primary issue with regard to claim 16 was whether the claim required both computer and telephone capabilities for receiving and transmitting data, or whether it required only one of the capabilities. Medgraph argued that the written description supports a disjunctive construction (i.e., that the claim required only one of computer and telephone capabilities). In support for this position, Medgraph pointed out that the specification states that the invention transmits data either over telephone lines or over the Internet.

Medtronic argued that "and" means "and" and not "or" because claim terms are to be given their plain and ordinary meaning. In addition, Medtronic argued that the written description teaches that the invention could possess both computer and telephonic capabilities, but only use one at a time.

The Federal Circuit held that "and" will only be interpreted as "or" when the specification compels a disjunctive ("or") construction. Because the written description of the '124 patent does not compel a disjunctive construction for "and”, the claim term was given its plain and ordinary meaning. Thus, in order to infringe, the Medtronic device must have possessed both computer and telephonic capabilities. Because the Medtronic system is not capable of transmitting patient data by telephone, the Federal Circuit held that the District Court correctly granted summary judgment of noninfringement of claim 16 of the '124 patent.


It is both common and permissible to define a structural element by reference to the function it performs rather than solely by structural language. See, e.g., section 2173.05(g) of the M.P.E.P.:

“A claim term is functional when it recites a feature “by what it does rather than by what it is” (e.g., as evidenced by its specific structure or specific ingredients). In re Swinehart, 439 F.2d 210, 212, 169 USPQ 226, 229 (CCPA 1971). There is nothing inherently wrong with defining some part of an invention in functional terms. Functional language does not, in and of itself, render a claim improper. Id. In fact, 35 U.S.C. 112(f) and pre-AIA 35 U.S.C. 112, sixth paragraph, expressly authorize a form of functional claiming (means- (or step-) plus- function claim limitations discussed in MPEP § 2181et seq.). Functional language may also be employed to limit the claims without using the means-plus-function format. See, e.g., K-2 Corp. v. Salomon S.A., 191 F.3d 1356, 1363 (Fed. Cir. 1999). Unlike means-plus-function claim language that applies only to purely functional limitations,… functional claiming often involves the recitation of some structure followed by its function. For example, in In re Schreiber, the claims were directed to a conical spout (the structure) that “allow[ed] several kernels of popped popcorn to pass through at the same time” (the function). In re Schreiber, 128 F.3d 1473, 1478 (Fed. Cir. 1997). As noted by the court in Schreiber, “[a] patent applicant is free to recite features of an apparatus either structurally or functionally.” Id.”

However, as is clear from the cases discussed above, one must be careful in doing so. And it is preferable to use a term such as is "made to," "designed to," or "configured to" rather than the broader term "can."