INTRODUCTION
Reviewing previously issued patents (prior art) is an essential step in determining if a seemingly novel invention is patentable. Prior art searches have traditionally been done by searching the paper files of issued patents. With the introduction of on-line services offering searchable databases containing patent information, some prior art searching can now be done with a few computer commands. But how extensive of a search can be done using the on-line databases?
This paper looks at one aspect of that question - how far back can searches be taken using on-line databases. Specifically, this paper explores the tools and methods needed to search for prior art that may exist before 1971. The companion question is how to do prior art searches that are not covered by the on-line services. These questions are answered only for domestic patents, those issued in the United States; similar questions also existed for foreign patents.
BACKGROUND
For an invention to be patentable, it must be novel, useful, and have an inventive step. A novelty, or prior art, search is a necessary step in the patenting process. A prior art search entails finding and reviewing all previously granted patents that may have an impact on the novelty of the invention in question. The search is usually done by the inventor, the applicant (if different than the inventor), a law firm hired to prosecute the patent, or a professional searcher. Both domestic and foreign patents need to be searched because the publication of information anywhere in the world prior to filing a patent application may bar the granting of a patent for an invention (this restriction varies considerably between countries). For some technologies, such as biotechnology or computer related equipment, a novelty search may only need to go back twenty years because the technology did not exist prior to the mid-1970's. Other technology, however, existed when this country was founded and relevant patents dating from the early 1800's may exist; these patents have to be found and reviewed even though the patent has expired (a United States patent may be issued for a maximum of seventeen years from granting or twenty years from the application date).
Prior art searches have traditionally been done at the public search room of the United States Patent and Trademark Office (USPTO). There, a searcher can look up patents by class and subclass and review the relevant patents granted by the USPTO as well as the "file wrapper", the additional paperwork and correspondence the took place during the prosecution of the patent. This information, all in paper form, is kept in containers called the "shoes". The USPTO has all patents granted since the inception of the USPTO (1790).
A newer method for patent searching, using special databases provided by various on-line services, has emerged in the 1990's. These databases can be searched in different ways: keywords, patent number, inventor, class and subclass (as defined by the USPTO) and others. The computer search can be done from a remote location and provide at least the front-page information of a granted patent. Most services also offer some sort of document delivery system that will deliver the entire patent to the searcher. These searches may be quicker than actually searching the "shoes", but these databases have one very large drawback - none of them allow searches all the way back to 1790. In most cases, the databases only include patents back to the early-1970's. As previously discussed, this lack of coverage does not effect some technology areas because of their newness. But for other technologies, this restricted time-frame can be a detriment. Many prior art searches must reach back before 1970. How to do that, then, is the question.
DISCUSSION
The preferred method for prior art searches is using the public search room at the USPTO. Those that are close enough to the Arlington, Virginia, facility may choose to do the search themselves. Others choose to hire a professional searcher. These searchers are involved with prior art searching everyday, have developed an effective and efficient search strategy, and may have cultivated relationships with some the of the examiners so that the examiner will allow the searcher to look at the prior art collected and used by the examiner in the course of their job (these private files are generally more comprehensive than the information that can be found in the public search room). The USPTO has all issued patents back to 1790, when the USPTO was created. The public search room is available to the general public and searches can be done for free.
Another method is to use the satellite libraries, the Patent and Trademark Depository Libraries (PTDLs). Each state has at least one PTDL and many states have multiple libraries. A list of locations can be obtained from the USPTO web-site (http://www.uspto.gov). Searches can be done on text back to 1971 and on patent number or class and subclass back to 1790 although some PTDLs do not have the patent images for the earlier patents. The availability and coverage varies with each PTDL; only some have images of all the patents back to 1790. As with the public search room, there is no cost for using the PTDL (there may be some charges for printing and copying). The PTDLs are also open to the general public.
A third option for off-line searching is the PTDL partnerships, which consists of three PTDLs chosen to become regional centers for disseminating patent information. Two sites are currently operating: the Sunnyvale (CA) Center for Innovation, Invention, and Ideas (SCI3) and the Great Lakes Patent and Trademark Center (GLPTC) in Detroit, MI. The third center will be at Rice University in Houston, TX. These centers use the automated patent image retrieval system similar to the one at the USPTO. All patent information, including file wrapper information, is available at the partnership libraries. Unlike the other PTDLs and the public search room, these centers charge a user fee. More information concerning the partnership libraries can be retrieved from the USPTO web-site.
Prior art can also be searched using specialized databases offered by on-line services such as Dialog (http://Dialogweb.com), Questel/Orbit and Q-Pat (http://www.questel.orbit.com and http://www.qpat.com), Corporate Intelligence (http://www.1790.com), Lexis (http://www.lexis.com), and Westlaw(http://www.westgroup.com). Users must subscribe to these services and fees are charged for use. Each service offers search capabilities for United States patents, provides different information for each patent (each service at a minimum will provide the front page information for a patent) and have different coverage dates. The following discusses the relevant databases and how far back patent searches can be done.
Dialog uses databases provided by Derwent. These databases allow full text searching for farm and agriculture patents back to 1965, chemical abstracts to 1970 and engineering patents to 1974. Questel/Orbit and Q-Pat provides searches back to 1974. Lexis provides searches for utility patents to 1975 and design and plant patents to 1976. Westlaw provides similar coverage.
The one subscriber on-line service that provides searches significantly before 1971 is Corporate Intelligence which allows full text searching for all patents issued since 1945. Additionally, imaged replicas of the patents issued before 1945 can be accessed by patent number or by hyperlink (pre-1945 patents referenced in a patent are linked and can be accessed by clicking on the link). There were reportedly some problems with the titles (possibly caused by scanning problems). For some pricing plans, being able to search pre-1971 patents may be considered an option that incurs an additional charge for use.
In addition to the subscriber services, there are free searchable lists on the internet. Currently, only IBM Patent Server (http://www.ibm.com/patents/) provides text and images for patents. The IBM Patent Server is free and provides for searches back to 1971. The Source Translation and Optimization (STO) site can be searched by using the classes and subclasses maintained by the USPTO or by patent number. The site, http://www.sunsite.unc.edu/patents/intropat.html, retrieves the patent number and title for patents from 1970 to 1995 and patent number only for patents from 1790 to 1969.
In a June, 1998, press release, the USPTO announced plans to introduce an internet site with a searchable database for all United States patents granted from 1976 to the present. The text of the patents will be available in November, 1998 and images will be available early-1999. The full text will be searchable.
CONCLUSION
While some, specific searches for pre-1971 prior art can be done on-line, the databases are limited in number and do not extend back far enough to be of use to the "older" technologies. In these cases, the only way to search prior art is to use the USPTO public search room, either personally or through a professional searcher. Even when on-line searching is possible, the preferred method still appears to be the paper copies at the public search room of the USPTO.