Searching Deeper for
Patents and Literature...

Timeline
Go FORWARD and BACKWARD in TIME by searching for later patents which reference the one in question, or the references to prior patents contained in the patent itself. This information is available and linked on the major government patent sites. For the most part these references will be extraneous, because they may be drawn from completely unrelated technology areas, or may address extremely fine points of similarity. Usually a quick look at the title and abstract will be all that is necessary. There will often be wheat among the chaff, however. The odd patents that seem to show up as references are a result of the way the US patent system classes are constructed. Patents are related to one another because of their similarity of functional elements, not because they belong to a particular area of technology.

Inventors
Search for additional patents by the same inventor(s) to see if there has been earlier or later work. You will generally find strong continuity for individuals: People work on things for a long time.

It may also be useful to search for papers by the individuals. Try Mom - The Mother of All RP Bibliographies first. Papers can also sometimes be fortuitously located directly on the web by searching on the inventor's name, or by searching on the inventor's name within an affiliated corporate or institutional site.

If you don't have full web access to the resources of an engineering college library, many local libraries now provide academic databases within their web sites. These often go back 15 years or more. You will likely need a library card account, however. These databases are adequate for many study purposes, but engineering databases with greater depth may be necessary to be definitive.

Local engineering colleges will have subscriptions to the ENGINEERING INDEX or the COMPENDEX. The INSPEC INDEX and the APPLIED SCIENCE AND TECHNOLOGY INDEX may also be helpful. The INSPEC has a strong electronic / optical slant and the ASTI covers some trade press that the EI does not. Neither is as complete as the EI for rapid prototyping, but both may uncover sources that the EI misses. Almost all academic institutions are happy to have civilians in their midst, and at any rate, this is where to find the papers themselves.

Assignees
Development often stays within a company or an institution, but may be supplemented by other individuals. Search on the ASSIGNEE to find similar work. Note that the literature indexes mentioned above can also be searched by institution or affiliation.

Some assignees are difficult and tedious to search because they have thousands of patents, or because their names have many variations, or words in common with many other institutions. Also some corporations obtain patents under the names of subsidiaries and/or umbrella or holding-company names. Universities often assign patents to a sub-organization, as well. Use Boolean logic and keywords for large companies and institutions. It is usually helpful to use a Boolean form such as UNIV* < NEAR > TEXAS for large universities.

The assignee field is frequently missing in the in the published patent applications database. This is intentional and is one method attorneys use to bury information. Try searching the entire full-text database, rather than just assignee field, for the assignee's name. It's also useful to search for all the inventors from that assignee and any attorneys the organization uses indicated on other patents or applications. These field searches can be done quickly. Searching full-text across all applications for an assignee name can be time-consuming, however.

RP Patent Classes
Search the PATENT CLASS for additional pertinent information. This can be more work than it sounds. Many classes have thousands of patents assigned to them over the course of many years. One's head may explode if too much of this material is taken in all at once. The search can be narrowed by searching the Class/Subclass, but there is a likelihood that some pertinent material will be missed. It may also be possible in some cases to narrow the search by limiting the time period in question. A better way of limiting the search may be to bomb the class with your keywords.

Here again, be forewarned that it is possible to miss significant material if the attorney or applicant has intentionally buried it. The US Patent Classification system also is not carved in stone. It frequently changes as new classes are added, combined or eliminated.

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