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COMPUTING AND THE L AWCOMPUTING AND THE L AW

The Significance of Prior ArtBrian M. Gaff, McDermott Will & Emery, LLP

Bruce Rubinger, Global Prior Art

An understanding of prior art is critical whether you’re writing a patent application or embroiled in patent litigation.

P rior art—historical infor-mation on inventions and discoveries—is an important consideration

when working with patents. It can limit what a patent applicant can claim as an invention. In litigation, it can invalidate a patent that’s being asserted against an accused infringer. Identifying and under-standing prior art is a high-stakes challenge.

For an expanded discus-sion on this topic, listen to the podcast that accompanies this column at www.computer.org/portal/web/computingnow/computing-and-the-law.

WHAT IS PRIOR ART?Generally speaking, the term prior art describes any information about an invention before a certain date. For example, when there’s a patent on an invention, prior art is infor-mation about that invention from before the inventor applied for the patent. Prior art information might be documentary, such as an article in a technical journal; the author might be someone other than the

inventor, which would show that dif-ferent people were working in the same technical area. Another per-son’s earlier patent might be prior art as well.

Products offered for sale and proto types can qualify as prior art. For example, if an inventor sells a product before filing a patent ap-plication on that product, that sale might be prior art. Similarly, sales by another party—such as a competi-tor—might be prior art, too.

For an invention claimed in a US patent that was filed on a cer-tain date (known as the effective date), Section 102 of US Patent Law defines prior art to be any patent issued from anywhere in the world and any printed publication that de-scribes that invention that predates the effective date. Also included as prior art are public use and sales predating the effective date. Prior art under Section 102 is sometimes called anticipatory prior art be-cause it “anticipates” the claimed invention. In other words, this type of prior art discloses the claimed in-vention’s every feature. This shows that the claimed invention isn’t

novel and therefore isn’t entitled to a US patent.

Prior art that isn’t anticipatory can still be relevant. For example, if the differences between the prior art and the claimed invention are minimal in the eyes of a person experienced in the invention’s sub-ject matter, then the invention is considered legally “obvious” and, ac-cording to Section 103 of US Patent Law, that invention isn’t entitled to a patent. This type of “obviousness prior art” must still predate the ef-fective date.

Sometimes a single piece of prior art is used to show obviousness by arguing that the minimal differences could be overcome by simple modi-fications by an experienced person. It’s also common for two or more pieces of obviousness prior art to be combined. The result is a mental unification of what’s disclosed in each, consideration of the aggregate, and comparison of the combina-tion against the claimed invention’s features. Features missing from one piece of prior art are typically found in the other prior art that is part of the combination.

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HOW IS PRIOR ART USED?Prior art is typically considered when writing a patent application and when challenging an issued patent’s validity. Patent applica-tions should be written to show how the invention differs from prior art. In validity challenges, finding prior art that shows that the claimed invention was known before the effective date can be a powerful weapon for an accused infringer in patent litigation.

Prior art and patent applicationsWhen filing a patent application, an engineer or developer tends to believe that minimal searching is preferred because, for example, he or she is unaware of any simi-lar technology. Indeed, there’s no requirement for patent applicants to search for prior art. However, in reality, just about every company operates in a crowded space, thus it’s essential to identify, understand, and distinguish an invention from relevant prior art. By reviewing and understanding prior art, an inventor can ensure that his patent applica-tion has the widest possible scope.

Prior art can’t be ignored—it will eventually surface and un-dermine a patent’s validity and hamper a company’s ability to pro-tect its technology. Thirty years of data collected by Global Prior Art, a company that conducts patent re-search, including worldwide patent searches, shows that a majority of granted patents can be invalidated by an aggressive, competent prior art search.1 So, despite a limited initial search, after a patent issues and its owner attempts to assert it against a competitor, the competi-tor will request a rigorous prior art search. Another instance where prior art is likely to emerge is if a startup seeks funding from ven-ture capitalists or is in acquisition discussions. With such high stakes, it’s quite common for investors to

initiate a solid due diligence search with a professional prior art search firm.

Prior art identification is the first step in creating strong, valuable pat-ents. Understanding prior art allows a patent attorney to draft claims that distinguish over it while pro-tecting and covering critical future products. During this stage, close in-teraction between the attorney and the inventor is important. Claims are typically drafted to ensure nov-elty, broad coverage, and the capture of commercially valuable product space; this transforms an invention into a valuable patent, and ensures that the claims don’t cover prior art, which would result in them being declared invalid.

Prior art and patent challengesIn the US, issued patents are pre-sumed valid. There are, however, ways to challenge validity:

• litigation, either in US Federal District Court or before the Inter-national Trade Commission; or

• ex parte reexamination or an inter partes review (IPR), administrative procedures through the US Patent and Trademark Office.

Challenges to validity generally arise when a party—usually a patent owner or its exclusive licensee— accuses another party of infringing a patent. Usually the accused infringer and/or the infringer’s attorneys look for prior art in the same technical area as the patent. The prior art is compiled and reviewed in a legal context to determine if it anticipates the patent’s claims or renders them obvious. Attorneys might retain an independent technical expert to help with this assessment, especially if there’s a need for an expert to testify in court.

Persuasive arguments of antici-pation and obviousness go a long

way in providing a defense to allega-tions of patent infringement. If the patent can be shown to be invalid because the prior art anticipates or renders the claims obvious, there can’t be any infringement. That is, someone can’t infringe an invalid patent. However, because of the presumption of validity, proving in-validity in court requires “clear and convincing” evidence. That’s stron-ger evidence than what’s needed in other types of civil litigation in which only the “preponderance” standard is used. Preponderance requires that the evidence show at least a 51 percent likelihood of what you’re trying to prove; clear and convincing requires a much higher percentage than that. However, it’s less of a burden than the “beyond a reasonable doubt” standard used in criminal trials.

A party challenging a patent in the US Patent Office usually compiles a collection of prior art ref-erences as its first step. It submits them along with the correspond-ing legal arguments as part of a formal request to initiate a patent reexamination or review, which are administrative procedures that cost less than litigation. The arguments submitted are strengthened when they rely on prior art that the Patent Office didn’t review during the pat-ent’s prosecution. Also, the Patent Office reviews the prior art evidence under the preponderance standard.

HOW IS PRIOR ART FOUND?There are three distinct levels of prior art searching, each offering different levels of coverage and suit-ability. At the low end are low-cost patentability searches, typically achieved with minimal coverage and quality. These efforts usually entail four to five hours of search-ing Patent Office websites using keyword strings. Many patents are based on such limited efforts. The search isn’t intended to be thorough but to pick up low-hanging fruit.

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This approach is more appropri-ate for a company filing low-value patents or when the issued patent quantity is more important than the issued patent quality.

The midpoint level is some-times called the “accelerated exam search,” which has more rigorous coverage and is typically recom-mended for any important patent. The US Patent Office has outlined the requirements of this type of search. It entails five to six days of search effort, including

• between two and three days for a manual search of US and international patents in core patent classes (categories), aug-mented by keyword searching in other classes; and

• between two and three days of an English-language, non–patent literature search that encompasses other kinds of printed publications, such as technical journals.

The high-end level is the invalid-ity search. It extends the coverage of an accelerated exam search on

several fronts. First, the US patent search coverage is expanded to in-clude a manual search of all core classes or subclasses, to pick up im-portant patents filed in secondary categories. This approach typically identifies patents that were missed by a keyword search because they use other terms. Next, the US lit-erature search is extended to other key sources such as databooks or documentation on earlier product introductions. In addition, serious international searching is usu-ally done, including searches of Japanese, German, and European patents. For accuracy, the search should be implemented in the native language (namely, Japanese and German) documents rather than searching English abstracts.

For many patent applications, the coverage that an accelerated exam search provides is sufficient. The broader coverage of an invalid-ity search should be considered for high-risk situations, including when filing strong patents around a com-pany’s core technology or assessing the patent’s strength before assert-ing it against a competitor.

Knowledge of prior art is critical. It’s a prime con-cern when drafting patent

applications, challenging patents, and defending against allegations of patent infringement. It’s advisable to invest the time and resources to understand prior art: turning a blind eye to it often leads to undesirable consequences.

Reference1. B. Rubinger, “Locating Prior

Art Gold: The Five Keys to Successfully Uncovering Strong Prior Art,” Intellectual Property Today, July 2011, pp. 2–4.

Brian M. Gaff is a senior member of IEEE and a partner at the McDer-mott Will & Emery, LLP law firm. Contact him at bgaff@mwe.com.

Bruce Rubinger is a life member of IEEE and the managing director and founder of Global Prior Art. Contact him at rubinger@globalpriorart.com.

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