Board Affirms Obviousness of Overlapping Ranges

March 2, 2012 – Blog Post

In Ex parte Bouzekri (Appeal 2010-005203), the BPAI affirmed the examiner’s finding of obviousness and reiterated some important points which often arise in patenting:

  • overlapping ranges are prima facie obvious;
  • preferable ranges are not dispositive of non-obviousness (e.g., do not necessarily provide a “teaching away”); and
  • attorney argument alone that a claim element is different from a similar element described in the art may not overcome an Examiner’s finding of inherency.

The first claim of the application recited a cold-rolled aluminum killed sheet steel, comprising, by weight, between 0.053 and 0.080 % carbon, between 0.15 and 0.424% manganese, between 0.010 and 0.100% aluminum, between 0.0020 and 0.0060% nitrogen, the remainder being iron and impurities resulting from production, and wherein the steel has a content of carbon in solid solution (Css) of at least 50 ppm, wherein the sheet has a rate of elongation of between 3 and 8%.

The primary reference applied by the Examiner, JP H06-093329 A (Kobayashi), described a carbon content, in a certain intra-steel form, of 50 to 200 ppm, and a carbon content of 0.03 to 0.3 wt.% (i.e. 300 to 3000 ppm). Regarding the range of carbon in solid solution claimed (at least 50 ppm), the applicants had argued that the carbon “in solid solution” was distinct from those ranges taught in Kobayashi, and that Kobayashi taught “a goal range of 4-11 ppm” of such carbon.

The examiner had nonetheless pointed to a figure in Kobayashi, disclosing a range of 0 to 50 ppm of the allegedly identical sort of carbon, (Css), a point which was not challenged by the Appellant.

The examiner argued that adjusting the content within a range up to 50 ppm would have been obvious for the purpose of adjusting or maximizing the bake curability of the steel. That is, there was an overlap of the range of solid solution carbon content at 50 ppm.

The BPAI concluded that even if the carbon range 50 to 250 ppm was to a different carbon, the solid solution carbon range derived from Figure 1 of the prior art had an endpoint at 50 ppm (notwithstanding the preferred range of 4 to 11 ppm) was sufficient to render the range “at least 50 ppm” obvious based on this point of overlap. The Board explained that, “in ‘cases involving overlapping ranges, we and our predecessor court have consistently held that even a slight overlap in range establishes a prima facie case of obviousness’ In re Peterson, 315 F.3d 1325, 1329 (Fed. Cir. 2003). Furthermore, ‘in a section 103 inquiry, ‘the fact that a specific [embodiment] is taught to be preferred is not controlling, since all disclosures of the prior art, including unpreferred embodiments, must be considered.’’ Merck & Co.Inc. v. Biocraft Labs., Inc., 874 F.2d 804, 807 (Fed. Cir. 1989) (quoting In re Lamberti, 545 F.2d 747, 750 (CCPA 1976).)”

The Board further acknowledged that Kobayashi clearly preferred that the solid solution carbon content was in a range of 4 to 11 ppm, but affirmed the Examiner’s position that there would have been a motivation to increase the content to 50 ppm (well beyond the preferred range) based on the theory of optimizing a result effective variable so as to maximize the bake curability.

Practice tips to be derived from this are that preferable ranges and fallback limits for ranges should be included in applications whenever possible. Here, a preferable range of “greater than 50 ppm,” or “at least 55 ppm,” may have distinguished this application over Kobayashi. Also, it is generally not persuasive to rely on a “teaching away” in the prior art based on a preferable range. Rather, the a reference should best indicate that the modification will render the prior art substance unfit for its intended use, or, in a best case scenario, unfit for any use.