Can my patent protect me from liability for infringing other patents?
One of the most common misconceptions regarding patents has to do with the difference between patentability (or novelty) and infringement. A patent does not give its owner the right to make an invention free from liability. Instead, a patent provides the owner with the right to exclude or license others to use the patented invention.
What is the difference between patentability (novelty) and infringement?
To be patentable, an invention has to be new and unique over the prior art. Prior art generally consists of prior patents, printed publications, devices and methods in public use, etc. Basically, whether or not you can patent your invention depends on whether your invention is new over what has already been done.
Even if you own a patent, you might still infringe someone else’s patent. Infringement relates to whether your product or method contains all the limitations (i.e., features) of at least one claim in a patent.
Consider the following:
The prior art discloses the combination AB. Your invention is comprised of the combination ABC.
To be patentable, your invention must be new and unique over the prior art. In our hypothetical above, the prior art shows a combination of AB (such as a prior art patent showing a structure with two features). Your invention consists of ABC. In other words, you add a new feature C. In this example, your invention would be patentable because it includes a new feature (aka “point of novelty”) that is not shown or suggested in the prior art.
Let’s turn to infringement. If every limitation of at least one independent patent claim must be found in the accused device, you have “literal” infringement. In the example above, if you made a product with features ABC, would this product infringe the prior art patent that claims AB? Notice that we said product, and not invention. Infringement activities involve using, making, selling or offering for sale (advertising). Mere abstract ideas do not infringe.
In the above example, your product would infringe the patent literally. A helpful way to analyze literal infringement is to list each limitation or element of each independent claim in a chart. Then go through each element, and place a check next to each element that is found in your product. If you check off each element in an independent claim, you have “literal infringement.” If one or more elements are not checked, then you do not have literal infringement.
Doctrine of Equivalents (DOE)
To be thorough, however, infringement under the doctrine of equivalents should also be considered. This is a much more in-depth analysis that generally requires review of the file history, or prosecution history, of the patent, including the cited prior art and the back-and-forth communications between the patent examiner and the applicant.
If in doubt, consult your patent attorney. You may want to have a non-infringement opinion prepared in order to minimize the chances of enhanced damages (multiple money damages, up to three times).