42 (2) (1990), p. 59.
JOM is a publication of The Minerals, Metals & Materials Society
Prior to committing the resources of time and money to the preparation and filing of a patent application, it makes good sense to first undertake a patentability search. While inventors often tell patent attorneys that there is nothing like their product on the market, patentability involves much more than what is on the market alone. Specifically, an amazing array of ideas have been patented, but for some reasonfor example, bad timing, lack of suitable materials, financial difficulties or whateverthey have not yet found their way into the marketplace.
By researching the records of what has already been patented (i.e., a patentability search), an inventor not only reduces the risk of expending effort and money on an invention that is not new, but he or she also aids the preparer of a patent application in emphasizing the true novelty of the invention. Unfortunately, the patentability search is not without its limitations. It is useful, therefore, to examine the search process so that its value and shortcomings can be appreciated.
The number of U.S. patents is rapidly approaching five million. Obviously, it is not reasonable or even desirable to examine every patent for relevance to a new invention. While the long-term goal of the U.S. Patent and Trademark Office is to automate the patent search, attempts at automation have met with limited success and thus far involve only a small percentage of U.S. patents. Not the least of the problems of automating patent searches is that much of the disclosure of many patents is contained in the drawingsa factor which imposes large demands on the memory capabilities of current computer systems.
As a result, patent searching has remained largely unchanged over the years. To aid in conducting a search, the Patent and Trademark Office employs a patent classification system, the primary characteristic of which classifies patents according to the utility of the invention. For example, arts and instruments having like functions, producing like products or achieving like results are classified together. Subject matter is divided into major classes, each with a hierarchy of subclasses. Overall, there are over t00,000 classifications. Copies of the patents are arranged in the public search room of the Patent and Trademark Office according to this classification system in row upon row of "shoe" boxes, with most subclasses requiring several such boxes. Conveniently, most patents are classified in more than one subclass, so the public search file ultimately includes many more than the five million original patents.
Performing a good patent search is an art. Economics dictate that only limited time can be spent on the search and analysis of the selected patents. The patent examiners are, for the most part, helpful in suggesting likely classifications to search in their areas of expertise if a dead end is reached. Ultimately though, only the most pertinent subclasses can be searched. Of course, with files containing millions of pieces of paper, there is a certain risk that pertinent art could be missing or misfiled in the public search room. However, since each examining group within the Patent and Trademark Office has its own search files, it is possible that an examiner could cite, during examination of a patent application, a patent that was missing from the public search files.
The patent examiners often make their own subdivisions of the official subclasses. This can be useful where a subclass includes an unusually large number of patents. The examiners) files can be used for a search with the permission of a primary examiner. However, an examiner will perform a patentability search or give an opinion on patentability prior to the filing of an application. Many examiners also maintain within the classification system additional "shoes" containing miscellaneous art such as foreign patents and other publications, but these collections tend to be rather haphazard.
The Patent and Trademark Office also maintains copies of the patents issued by the other major industrial countries, but these patents are arranged numerically and are not classified as to subject matter. Hence, patent searches for the most part only include U.S. patents. Likewise, the patent examiners search only U.S. patents except for the miscellaneous materials that they may have accumulated.
While many libraries around the country maintain copies of U.S. patents, like the foreign patents in the Patent and Trademark Office, they are arranged in numerical order only. It is possible to obtain from the Patent and Trademark Office a list of patents classified in particular subclasses which could be used to identify patents arranged numerically, but this is a very inefficient way to perform a search.
There are some on- line services which provide the capability of searching patents through a computer terminal. Such services are of limited usefulness, however. First, they only have patents issued in the last few years. While some have full text of the patents in their system, they do not include the drawings. They also require selection of key words which appear in the text.
Of course, prior art which could affect the patentability of an invention
includes not only United States patents, but all other publications, and, in
fact, just about all forms of public knowledge including public uses by others.
There is no economical, systematic way that all sources of prior art can be
searched. However, a patent search performed by a skilled searcher is a cost
effective means for locating pertinent prior art prior to filing a patent
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