Defenses to Patent Infringement

Patent law is one of the most specialized branches of the law.

If you have been named in a patent infringement case or believe that you may have a case to pursue compensation and relief for patent infringement on a patent that you hold, a firm of experienced patent infringement lawyers is your best resource for information.

There are, however, a few principles of patent infringement litigation that are helpful to know. Among the most helpful to understand in building your case are the defenses to patent infringement that are most often used in patent infringement cases. The two basic defenses to a patent infringement lawsuit are non-infringement and invalid patent.

Non-infringement defense to patent infringement lawsuits:

In the first, the defendant tries to prove that their product or process does not infringe upon the existing valid patent for one or more reasons. It is usually the first line of defense to be considered. There is an infringement upon a patent when each "claim" in the patent is matched by an element of the infringing product. If the item that is claimed to be infringing does not match each of the claims in the patent, the case may be dismissed because no infringement exists.

In order to prove whether a device or process infringes upon the named patent, the judge or other examiner will first do a careful reading of the claims of the patent. Suppose the patent is for a device that has the purpose of extending the waistband of a skirt by means of an extension of fabric that is fitted with a buttonhole on one end of the extension and a button on the other.

A second company produces a product which consists of a fabric extension that has a buttonhole on one end, and three buttons at various points on the extension so that it can be adjusted to fit the waistband more accurately. The examiner must examine each of the "claims" made in the patent and then match them to the elements of the device in question. In this case, the examiner may find that patent infringement does exist because each of the claims in the patent is matched to an element in the infringing device, which is actually a modification of the patented process.

Invalid patent defense to patent infringement lawsuits
The other most common tack in patent infringement lawsuits is an attempt to invalidate the patent on one or more grounds. In order for there to be a judgment of infringement, their must exist a valid patent; it must be in force at the time of the alleged infringement; and it must meet all the conditions for obtaining a valid patent.

While one might assume that the very issuance of a patent would substantiate its validity, that's often not the case. There are a number of things that might invalidate an existing patent.

1. A prior art or novelty search may turn up descriptions or depictions of the patented application that existed before the date of invention. In this case, the patent may be invalidated because the application or item was not the first depiction of the device. The description or depiction must give enough detail that a person of "reasonable skill" could make or work the device based on that description.

2. The defense may hold that the patent is for a use or device that would have been obvious to anyone with reasonable knowledge or skill. If obviousness can be proved, then the patent may be invalidated and no infringement can have taken place.

3. The defense may charge that the patent holder did not exercise diligence in pursuing the patent application process. Most often, this charge will be brought if the patent's original application was outside the grace period allowed after publication of the patented idea or device.

4. The defense may argue that the subject of the patent is not a suitable subject for patenting.

Those are the most commonly claimed grounds to invalidate a patent in patent infringement cases, but there are many other grounds which could be used to defend against a charge of patent infringement.

In addition, the interpretation of patent law and the definitions of the elements of patent law frequently undergo changes during the course of court cases. As the number of patent infringement cases continues to mount, new defenses are being tried and old ones struck down.

If you are involved in a patent infringement lawsuit or are considering one yourself, it's important to have an experienced professional on your side.

Consult a law firm that specializes in patent infringement cases to get a thoughtful and realistic evaluation of your chances.