Articles > Many Patents Are Now Subject to a New Ground for Attack

Many Patents Are Now Subject to a New Ground for Attack

by David L. Principe

The practice of filing continuation applications has been used by patent attorneys as a part of filing strategies on behalf of their clients for many years. A continuation application is a patent application that contains the same written description as an earlier-filed patent application by the same inventor, but it usually contains different claims and it is treated for examination purposes as though it were filed on the same date as the original application.

A recent decision by the Federal Circuit has cast a shadow over many continuation practices. In Symbol Technologies, Inc. v. Lemelson, 277 F.3d 1361 (Fed. Cir. 2002), a three-judge panel of the Federal Circuit held that the equitable doctrine of laches may be applied to bar enforcement of patent claims even though the applicant complied with pertinent statutes and rules if there was an “unreasonable” and “unexplained” delay in prosecution. The case involved patents covering machine vision and automatic identification technology and claimed benefit of the filing date of two applications filed in 1954 and 1956. A rehearing en banc was denied, and a writ of certiorari to the United States Supreme Court was also denied. Accordingly, prosecution laches as an equitable defense to patent infringement will be used to attack many patents issuing from continuation applications and will undoubtedly increase the costs of litigation and provide additional uncertainty for those litigants.

Continuation strategies

Continuation applications are filed for many reasons. For example, continuation applications are sometimes used when the patent owner obtains an allowance of narrow claims and decides to allow a first patent to issue quickly and to pursue broader claims in a subsequently filed
continuation application. Another continuation strategy is the “submarine patent,” in which a number of continuation patent applications are filed in succession in a daisy-chain fashion. Each successive continuation application is filed before the preceding application becomes abandoned. In this manner, the continuation applications can be kept alive for many years and in some instances for decades until a patent finally issues and pops to the surface to become a nuisance for unsuspecting competitors.

Another strategy employed by some patent applicants is to repeatedly file the same set of claims in successive continuations in order to stall prosecution. This strategy involves the following steps:

1) a continuation application is filed;

2) a first office action is received from the Patent Office;

3) a second continuation with the same set of claims is filed (including a petition for a three-month extension of time); and the process is repeated until the applicant decides to begin prosecution in earnest. If the applicant is willing to spend the money, this type of pattern can be continued for years for the sole purpose of keeping an application pending in order to respond to developments in the marketplace.

Don’t get “designed around”

In some instances continuation practice is used as an insurance policy to guard against a competitor designing a product that provides the benefits of the invention without falling under the specific language of the claims of the patent (a.k.a. “designing around”). For example, if the original patent claims turn out to be too narrow or the competitor designs around the patent, the patent owner can present broader claims through continuation practice in order to better protect the invention. In fact, the patent attorney can have the competitor’s product right in front of him or her while writing patent claims for examination by the Patent Office.

Prior to the most recent change in the patent term, a continuation patent was entitled to a full 17-year term from its date of issue. This term provided a great incentive for submarine patents and, in the opinion of many, provided too much of an advantage. In the mid-1990s, the patent term was changed to 20 years from the filing date of the earliest patent application, thus fixing the expiration of all the continuation patents to that of the original patent.  This change allowed the submarine strategy to continue but reduced its impact significantly. Now a typical submarine patent strategy may only result in five to 10 years of patent term as opposed to 17 years.

Patent owners will undoubtedly continue to use continuations as part of a comprehensive patent strategy.  However, the decision in Symbol will have to be considered carefully when planning continuation strategies in the future.