Claim Drafting – Transitional Phrases
This post was first published on July 17, 2014.
A transitional phrase is a part of the claim that connects the preamble and the body. The Transitional phrase determines as to whether a claim is “Open” “Partially Open” or “Closed.”
An Open claim includes additional unrecited elements i.e., if a claim, which is Open, recites elements A, B, C and D, then an article which includes elements A, B, C, D and E infringes the Open claim irrespective of the fact that the article has an extra element E which is not recited in the Open claim.
The term “comprising” in a claim makes the claim Open.
In, Gillette Co. v. Energizer Holdings, Inc., 405 F.3d 1367 (Fed. Cir 2005), a famous and much talked about case, the claim at issue recited “A safety razor blade unit comprising a guard, a cap, and a group of first, second and third blades. ” The accused infringing product included four blades. The court said that the word “comprising” makes the claim Open and hence, the scope of the claim encompasses all safety razors satisfying the elements set forth in the claim thus concluding that the accused product infringed the claim.
In another case, Power MOSFET Techs., LLC v. Siemens AG., 378 F.3d 1396, 1409 (Fed. Cir. 2004), where the term “comprising” was used as a transitional phrase, the claim element required a contact layer contacting with all the first and second semiconductor regions to form an interface. One of the issues here was to determine whether “contacting” required actual physical contact or whether electrical contact would suffice. It was agreed that the word “interface” used in the claimed element required physical contact. The patentee argued that the use of the term “comprising” as a transitional phrase signified that different forms of contact could be allowed and hence electrical contact would meet the claim term. However, the court said that using the term “comprising” as a transitional phrase does not remove the limitations that are present in the claim.
Terms such as “having,” “including,” “containing” and so on are mostly being used as alternatives to the term “comprising.” Although, there are some case laws in which it was said that the words such as “including” and containing” are synonymous with the word “comprising” it is almost always recommended that the word “comprising” be used as a transitional phrase if one intends to make the claim open.
Partially Open Claim
A partially open claim, like an Open claim, includes additional unrecited elements, but such additional unrecited elements do not materially affect the basic and novel characteristics of the claimed invention. The Partially Open claim defines a middle ground between completely open and completely closed claims.
The term “consisting essentially of” in a claim makes the claim Partially Open
In In re De Lajarte, 337 F.2d 870 (C.C.P.A 1964), the invention was directed to improving electrical insulation characteristic of a glass. The claim used the term “consisting essentially of” as the transition phrase and set out composition of many compounds. The applied reference, in addition to the compounds, had sulfur and carbon. The court held that the reference did not map onto the claimed invention as the Applicants had emphasized the fact the claimed invention gave improved electrical insulation.
In In re Janakirama Rao, 317 F. 2d 951 (C.C.P.A 1963), the claim at issue was directed to an optical glass consisting essentially of up to 75% cadmium oxide, 20-95% bismuth and 0.5 to 20 % silica. The applied reference(s) disclosed optical glass having the compounds as mention in the claim. The applicant argued that the transition phrase “consisting essentially of” distinguished his claim over the applied art. The court said that the only change allowed by using such transition phrase was the inclusion of ingredients, which would not materially affect the basic and novel characteristics of the appellant’s composition as defined in the claim. The claim rejection was upheld.
“Closed” claim, as opposed to the Open claim, has restricted scope i.e., if a claim, which is “Closed” recites elements A, B, C and D, then an article which includes elements A, B, C, D and E will not infringe the “Closed” claim.
The term “consisting of” in a claim makes the claim Closed.
- If the subject matter being claimed is directed to mechanical and/or electrical/electronics, using the transition phrase “comprising” is strongly recommended;
- Try and avoid using the terms “having,” “containing,” “including” and the like as much as possible;
- If the subject matter being claimed is directed to chemical art or biotechnology, considering using the transition phrase “consisting” or “consisting essentially of”;
- While using “consisting essentially of” consider additional unrecited elements which materially affect the basic characteristics of the claimed invention.