On Monday, the Federal Circuit decided American Medical Systems, Inc. v. Biolitec, Inc. The issue in this case was the construction of claim 31 of U.S. Patent No. 6,986,764. The particular issue was whether the preamble limited the claim.
A method for photoselective vaporization of tissue, comprising:
delivering laser radiation to a treatment area on the tissue, the laser radiation having a wave-length and having irradiance in the treatment area sufficient to cause vaporization of a substantially greater volume of tissue than a volume of residual coagulated tissue caused by the laser radiation, wherein the delivered laser radiation has an average irradiance in the treatment area greater than 10 kiloWatts/cm2 in a spot size at least 0.05 mm2.
The defendant in this case asserted that it did not perform “photoselective vaporization” of tissue as recited in the preamble. The district court agreed and entered summary judgment of non-infringement. The court held that the term “photoselective vaporization” referred to a specific wavelength for the laser radiation. The Federal Circuit reversed, holding that the preamble did not limit the claim.
The court began with the standard statements that there is no hard and fast rule as to when the preamble limits the claims, but that it is to be determined based on the facts of the particular invention described in the patent. Generally, however, a claim’s preamble does not limit the claim unless it recites essential structure or steps or is “necessary to give life, meaning, and vitality” to the claim. Whatever that means.
Based on the court’s standard jurisprudence on claim preambles, it reversed the district court and held that the preamble did not limit claim 31. All of the necessary steps to practice the invention are contained within the claims such that resorting to the preamble is not necessary.
Judge Dyk dissented in this case as he would hold that the preamble is a limitation of the claim. He suggests that the Federal Circuit’s claim preamble jurisprudence is a mess and that it is difficult to determine whether the preamble is limiting in any particular case. He further suggests that the court should revisit this issue en banc to make a clear rule that claim preambles are always limiting.
Judge Dyk presents a good point. What is the purpose of a claim preamble if it does not limit the claim? Due to the confusion on this issue, many practitioners do not use a claim preamble. Thus, you will see claims that simply recite “A method comprising: . . .” or “An apparatus comprising: . . .” Given that it is a bit of a crap shoot as to whether the preamble will be construed as a claim limitation, this seems to be a prudent course of action. If the description in the preamble is necessary for patentability of the claim, it should be placed in the body of the claim.
