Should you conduct a prior art search before filing a patent application?

The USPTO will only grant a patent if it’s convinced that the subject matter of the patent application is novel and non-obvious over anything publicly disclosed before the filing date of your patent application. In most cases, the Examiner’s issues with your patent application will center around issues of novelty and non-obviousness, which necessarily involve comparing your invention to publicly-available prior art – documents that already disclosed your invention before you did, or where your invention is merely an obvious variation of one or more such documents.

A prior art search, also known as a patentability search, involves a professional searcher reviewing draft claims that you send them, using a number of proprietary databases. The search often tries to replicate the search a USPTO Examiners would conduct, in the hopes of finding the same prior art.

Prior art consists of other patent applications, patents, scientific journals, instruction manuals, brochures, advertisements, PhD theses, Amazon product blurbs, and any other public material that was available before you filed your patent application. These documents are called prior art references or sometimes just references. Typically, the majority of the difficulty in getting a patent application granted by the PTO involves getting over references identified by the Examiner, either by making argument or amending the claims of the invention to distinguish from the references (so that as amended, the invention is no longer non-novel or obvious over the cited references).

A search therefore should give you a representative knowledge of what prior art is already out there floating around in the world, and gives you a chance to address that art in your patent application up front, before it gets rejected by the PTO. If there’s a lot of prior art in the field that reads on the elements of your invention, you are operating in a crowded field and may have to thread the needle to find a patentable niche that you can patent.

Conversely, if there is not much prior art, then you have breathing room to write your claims a little broader, and maybe you can expand the claims and cast a wider net to stave off future potential infringers.

Another benefit of a prior art search is that it gives you valuable information that you can use to collect additional data or include technical information in the patent application that directly rebuts the prior art. It’s not uncommon for patent application to specifically reference previous art, and to expressly state how it is different from the claimed invention and does not solve the same problems, or solves them in an inferior way.

However, searches have limitations. Primarily, there’s just a massive amount of publicly available information in the world, and much of it is not easy to find. Thus, even a highly thorough prior art search cannot guarantee that everything relevant is found. In addition, a search cannot predict the combinations of prior art references an Examiner might use to argue that the invention is merely obvious in view of these references.

Nevertheless, prior art searches can often answer the threshold question of whether the invention has a high probability of getting a patent, and to what extent the claims may have to be narrowed. Hence, it can be a relatively inexpensive tool to make a decision about whether to go forward with the more expensive and rigorous task of obtaining a patent.

Mechanics of conducting a prior art search

Generally, the patent attorney or agent will not perform the search him/herself. Instead, specialized search firms exist whose sole expertise is conducting literature searches. These firms have purchased access to several databases and are proficient in conducting literature searches.

However, at the outset of the search, a patent attorney will prepare a few sentences or claims describing the invention—these have the important keywords of the invention. The patent attorney will then send the claims to a search firm, along with any drawings, and the search firm will conduct the search and deliver a report, typically within 1-2 weeks.

The search results will usually consist of anywhere from about 5-15 different references. A good search firm will also provide detailed tables, identifying the key terms of the invention and connecting it to each reference. A table may look something like this:

In the above heat map, a red box means that the reference clearly discloses or teaches the invention element, yellow means the reference arguably or maybe discloses or suggests it, and green means that the reference does not teach or suggest it.

From glancing at the above heat map, an inventor can quickly see that element 4 appears to be in the clear and can support patentability, and possibly element 3 as well. Thus, this invention may have a good chance of being patentable.

Note that the search firms also do not analyze the actual probability that the component meets the legal standards of patentability. After the search, the patent attorney can review the references and provide a professional opinion about patentability. The attorney can also provide recommendations about how to draft the claims in order to evade the references as prior art.