In 2007, the Federal Circuit in Festo Corp. v. Shoketsu Kinzoku Kogyo Ka-bushiki Co. (“Festo 2007”)236 rejected a “foreseeability test [which] requires application of the function/way/result or insubstantial differences test.”237 The Federal Circuit clarified that an alleged equivalent “is foreseeable if it is disclosed in the pertinent prior art in the field of the invention.”238The Federal Circuit also held that an alleged equivalent “is foreseeable if it is known in
225 See id. at 1347.
226 Id.
227 Id.
228 See U.S. Patent No. 4,879,749, col. 1 l. 5 (filed Feb. 12, 1988). A divisional ap-plication is a patent apap-plication divided from its parent apap-plication. See David V. Radack, Understanding “Related” U.S. Patent Applications, http://www.tms.org/pubs/journals/JOM/
matters/matters-0406.html (last visited Aug. 14, 2015).
229 See Energy Transp. Group, 697 F.3d at 1358.
230 Id. at 1359 (internal quotation marks omitted).
231 Id. (emphasis omitted).
232 Id. at 1360 (internal quotation marks omitted).
233 See id.
234 See id. at 1347.
235 See id. at 1360.
236 493 F.3d 1368 (Fed. Cir. 2007) [hereinafter “Festo 2007”].
237 Id. at 1379.
238 Id.
the field of the invention as reflected in the claim scope before amendment.”239 This rule applies “even if the suitability of the alternative for the particular purposes defined by the amended claim scope were unknown.”240
In Festo 2007, the patent-in-suit related to a motor assembly.241 The claim at dispute originally did not include a sleeve bearing (or “sleeve” as a term used in the patent), however, it was included in a dependent claim.242 When submitting to the USPTO a German patent as a prior art, showing the use of a sleeve [bearing] made of non-magnetic material, the applicant amended the claim at dispute to recite “a cylindrical sleeve made of a magnetizable material.”243 On the other hand, the alleged equivalent was a sleeve made of
“a non-magnetizable material, aluminum alloy.”244
The Federal Circuit held that “use of non-magnetizable sleeves (including aluminum sleeves) was foreseeable under the original broader claim[.]”245 The patentee argued that “sleeve” was used to “shield against magnetic field leakage[,]”246 but the Federal Circuit found that the claimed sleeve “was not designed to shield the magnetic field but rather to enclose the magnets.”247 The German patent that the applicant submitted also indicated that a sleeve bearing could be made of a non-magnetic material.248 In addition, the speci-fication of the patent-in-suit showed “the possibility of using a non-magnetic material for the sleeve.”249 While describing that the use of magnetic material for the sleeve could reduce undesirable braking forces, the specification did not mandate such use.250 Therefore, the Federal Circuit concluded that “use of an aluminum alloy sleeve was foreseeable at the time of amendment” and, therefore, PHE applied.251
Under Festo 2007, whether a field relates to unforeseeability should be determined in view of the original claim. However, the technology in Festo 2007 could not show the difference between the fields of the original claim and amended claim because the claimed sleeve bearings in the original form and amended form were in the same or similar field.
239 Id. (emphasis added).
240 Id. at 1382.
241 See id. at 1371–72.
242 See id. at 1372.
243 Id. at 1373 (internal quotation marks omitted).
244 Id. at 1374.
245 Id. at 1382.
246 Id.
247 Id.
248 See id.
249 Id.
250 See id. at 1383.
251 Id.
Schwarz Pharma, Inc. v. Paddock Laboratories, Inc.252 may be a good example for illustrating the determination of unforeseeability under “the field of the invention as reflected in the claim scope before amendment.” There, the patent-in-suit related to pharmaceutical compositions containing Angiotensin Converting Enzyme (‘ACE’) inhibitors as an active ingredient and certain stabilizers as an ingredient that can prevent certain types of degradation of ACE inhibitors.253 Two claims were involved, and each claim recited a stabilizer limitation.254 One claim recited a “metal containing stabilizer” and the other claim recited “an alkali or alkaline earth-metal salt[.]”255 During the prosecu-tion, because of the examiner’s rejecprosecu-tion, those two stablizer limitations were amended as “an alkali or alkaline earth metal carbonate.”256 On the other hand, the alleged equivalent was magnesium oxide (“MgO”).257 Eventually, the Federal Circuit found that MgO fell within the definition of a “metal containing stabilizer” and that the patentee’s expert described “an alkali or alkaline earth-metal salt” as embracing MgO.258 Therefore, the Federal Circuit held that MgO clearly fell within “the territory between the language of the original and the amended claims.”259
Moreover, the Federal Circuit rejected the patentee’s argument that MgO was unforeseeable because MgO was not known as a stabilizer against one of those claimed degradations or was not used for the claimed ACE inhibitors.260 The ultimate question was whether the alleged equivalent was within the field of the invention.261 The Federal Circuit cautioned that “care must be taken not to sweep too broadly in defining the field of an invention[.]”262 That is, if the field of the invention is defined broadly, many objects may be considered as an equivalent. However, the Federal Circuit concluded that the patentee offered a very narrow definition of the field of the claimed invention.263 Re-ferring to the claim language, the Federal Circuit found that before being amended, the claims at dispute began with the phrase“[a] pharmaceutical composition which contains[.]”264 So, the Federal Circuit upheld that the
252 504 F.3d 1371 (Fed. Cir. 2007).
253 See id. at 1372.
254 See id. at 1372–73.
255 Id. at 1373 (internal quotation marks omitted).
256 Id. (internal quotation marks omitted).
257 See id.
258 Id. at 1376.
259 Id. at 1376–77.
260 See id. at 1377.
261 See id.
262 Id.
263 Id.
264 Id. (alteration in original).
field of invention should be “pharmaceutical compositions” in general rather than “pharmaceutical stabilizers that inhibit cyclization in ACE inhibitors.”265 Therefore, the Federal Circuit concluded that “MgO was known as a stabilizer in the field of pharmaceutical compositions,”266 and that the patentee failed to rebut the presumption.267