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Why Patent Claims Language Must Be Clearly Written

Posted on Sep 27, 2017 in Articles

This article originally appeared in The Legal Intelligencer on September 27, 2017.

Everyday business communication is hard enough. With all of the ­­subtleties and nuances of language, the message received by an individual may not match what was intended. But with patent claims, the need for definiteness is far greater. Convince the Patent Office to allow your patent claim with understandable meaning, and the resulting patent may (emphasis “may”) have value. If, however, the language of your patent claim is unclear, your patent may never issue (and even if it does, it may be very difficult to assert).

Consider the purchase of real estate property. There should be no question as to exactly what the purchaser is getting. The deed sets out with great precision where the property lines are located. The larger the area of the property, the greater the value of the property. And at any time, a surveyor can survey the property and identify its metes and bounds.

While there are considerable differences between real estate property and patent rights, there are strong analogies as well. When patent claims are broader (and cover more area), their value is greater. At the same time, patent claims provide important (and sometimes very significant) legal rights. The “lines” of the patent must be clear. Without knowing exactly what rights are being sought, the Patent Office will not issue a patent. If it does, the courts will be reluctant to enforce the patent.

That is why the words of a patent claim should be chosen with extreme care, and language that is not understandable should be excluded. Take the words “close” and “far,” words that are very imprecise and, as a result not advisable to put into a patent claim. The sidewalk is “close” to the front door of my house, but New York City is “far” from my home in suburban Philadelphia. On the other hand, New York City is “close” while Tokyo Japan is “far.” These words provide comparative information, but by themselves do not have clear meaning. That is why the Patent Office and the courts frown upon their use.

The Patent Office issued a precedential opinion last month (Ex parte McAward, 2015-006416, PTAB 2017) that deals with this very issue. Honeywell applied for a patent for a water detector that shuts off a water valve when flooding is detected. After appealing a claim rejection over indefinite language, the Patent Trial and Appeal Board affirmed the rejection.

The patent claim under appeal included many of the physical features that one would expect to find in such a product: a housing, a water sensor and a valve. The patent claim also included some unusual language: ” … the water detector is configured to be reliably installed by an untrained installer or a homeowner and to not require the services of a plumber or electrician to perform installation, thereby permitting widespread and cost effective adoption.”

It is impossible to determine exactly what this claim language is trying to ­protect. Words such as “reliably,” “untrained,” “widespread,” and “cost effective” are simply too vague for a patent claim. The courts would never enforce such a patent claim because the legal coverage is murky.

The relevant statute, 35 U.S.C. Section 112, is known as the definiteness requirement and (in the words of the precedential McAward opinion) “secures to the patentee all to which he is entitled” and “apprises the public of what is still open to them.” Patent Office examiners will reject a claim “if the metes and bounds of the claimed invention are not clear.” If patent claim language does not have definitive meaning, then the Patent Office “is justified in requiring the applicant to more precisely define the metes and bounds of the claimed invention by holding the claim unpatentable … as indefinite.” In this manner, patent claims “once fixed and issued, are as precise, clear, correct, and unambiguous as possible.”

The bottom line is that your patent claims must meet the definiteness requirement in order for you to receive an enforceable ­patent. Unfortunately there is a small problem. Is there a legal standard for ­determining whether the definiteness has been met?

Well, there was. The issue was previously addressed by the U.S. Supreme Court (Nautilus v. Biosig Instruments, 572 U.S. ____,134 S. Ct. 2120 (2014)), namely, that “a patent’s claims, viewed in light of the specification and prosecution history, inform those skilled in the art about the scope of the invention with reasonable certainty.” The phrase “skilled in the art” is key. Computer-based claims should be evaluated from the perspective of a computer engineer with several years of experience in the industry. Chemical claims should be evaluated from the perspective of a chemist with a good amount of time in the chemical industry, etc.

To this author, the Supreme Court’s ­standard was clear, until Ex parte McAward stated that the Patent Office would not follow that standard. The McAward ­standard is that a claim “is indefinite when it contains words or phrases whose ­meaning is unclear.” Thus, the perspective of a ­person “skilled in the art” may or may not be relevant. How did the McAward opinion justify the ­deviation from the U.S. Supreme Court? Because of various differences in the way the courts and the Patent Office interpret claims—the result of different burdens, standards of proof, and ability to modify claims in courts and the Patent Office (claims before the Patent Office can be modified, while claims before a court are 

The McAward decision is seen as 
controversial by the Patent Bar, with many attorneys insisting that the Patent Office is required to follow Nautilus. Nevertheless, after McAward, patent applicants may need to live with a more difficult standard than what Nautilus required.

If you are in the process of procuring patent protection, it is important that your claims include language that can be clearly understood. At the same time, ­patent claim language needs to be written as broadly as possible in order to maximize the value of your patent. These two goals can sometimes be conflicting; broadness of language may lead to ­unacceptable ambiguity. Yet both goals need to be pursued in order to obtain a ­patent that is enforceable and is as valuable as 

– By Lawrence E. Ashery


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