Skip to content

A claim’s “negative limitation” defines the invention in terms of what it is not, rather than with an affirmative description. In contrast, consider the following two cases:

  1. a claim with the limitation “said homo-polymer being free from the proteins, soaps, resins, and sugars present in natural Hevea rubber” in order to exclude the characteristics of a prior art product, was ruled to be definite because each recited limitation was definite. In re Wakefield, 422 F.2d 897; 164 USPQ 636, 638, 641 (CCPA 1970); and
  2. a negative limitation “incapable of forming a dye with said oxidized developing agent” was deemed definite because the boundaries of the patent protection sought were clear. In re Barr, 444 F.2d 588, 170 USPQ 330 (CCPA 1971).

Back to Patent Dictionary