Opinion ID: 210077
Heading Depth: 2
Heading Rank: 1

Heading: Adjoining Claims

Text: IXYS contends that the district court overstepped its authority under our mandate in IR I when it conducted a jury trial as to infringement under the doctrine of equivalents of the claims containing the adjoining limitation, i.e., independent claim 19 and dependent claims 22, 24, and 27 of the '699 patent. In the alternative, it argues that IR is foreclosed by prosecution history estoppel from resorting to the doctrine of equivalents. Because the latter argument is squarely presented for the first time and its resolution may affect future cases, we conclude that the most prudent course of action is to decide the case on this basis. In so doing, we expressly decline to decide the scope of our prior mandate with respect to the doctrine of equivalents. [P]rosecution history estoppel limits the broad application of the doctrine of equivalents by barring an equivalents argument for subject matter relinquished when a patent claim is narrowed during prosecution. Conoco, Inc. v. Energy & Envtl. Int'l, L.C., 460 F.3d 1349, 1363 (Fed.Cir.2006). [W]e review issues relating to the application of prosecution history estoppel de novo.  Id. at 1357. During the prosecution of the '699 patent, IXYS argues, IR added the adjoining limitation in order to overcome rejections under 35 U.S.C. § 112, paras. 1-2. IXYS argues that the examiner rejected claim 43 (which later issued as claim 19) because the applicants claimed, but failed to disclose, an IGBT mode of operation for the device. The addition of an adjoining limitation; in IXYS's view, limits the claimed structure to one that can operate as a MOSFET, and prosecution history estoppel therefore applies to prevent claim 19 and its dependent claims from reaching IGBTs under the doctrine of equivalents. [] IR makes two arguments in response. First, it asserts that prosecution history estoppel does not apply to its addition of the term adjoining because the resulting change in claim language was broadening, not narrowing. The claims, IR argues, are directed to structure rather than function, and the adjoining limitation simply clarified what structure was claimed. Second, IR argues that prosecution history estoppel does not apply because the amendment in question is only tangentially related to the asserted equivalent. See Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 740, 122 S.Ct. 1831, 152 L.Ed.2d 944 (2002) (There are some cases . . . where the amendment cannot reasonably be viewed as surrendering a particular equivalent. . . . [T]he rationale underlying the amendment may bear no more than a tangential relation to the equivalent in question.). We agree with IXYS that these arguments fail. As to IR's first argument, IR is correct that the amendment broadened the claim in certain respects  for instance, it eliminated the requirement that the conductive electrode at the bottom of the wafer be coupled to the drain conductive region, a requirement that the examiner described as unsupported by neither [sic] the technology nor the specification. At the same time, however, IR chose to introduce the term adjoining. This term excludes structures that might have been covered by the original claim language, because the support body of the old claim  apparently the further region of opposite conductivity type of the amended claim  was only required to support[] said lightly doped major body portion, not necessarily to touch it. The amendment therefore narrowed the scope of the claim, at least with respect to the addition of the term adjoining. Under such circumstances, IR cannot argue that the amendment was broadening merely because it eliminated some claim limitations. As to IR's second argument, we disagree with IR that the purpose of the amendment was tangential to the asserted equivalent. It is true that the reason given by the examiner for the rejection was that not all of the limitations in the original claim 43 were supported by the specification, and that IR overcame the rejection by amending the claim to contain only the structural limitations disclosed in the text of the specification and the drawing that became '699 patent figure 8. In this regard, IR is correct that the claim is not necessarily limited to a particular mode of operation, but rather covers a particular structure that, in practice, may or may not function in unexpected ways. However, IR's decision to claim that structure using the limiting term adjoining, whether or not required to overcome the rejection, cannot be described as only tangentially related to the equivalency of a structure with non-adjoining regions. With the amended language, IR recited precisely the structure it disclosed, and thereby overcame the examiner's § 112 rejection. See Schwarz Pharma, Inc. v. Paddock Labs., Inc., 504 F.3d 1371, 1377 (Fed.Cir. 2007) (The fact that the inventors may have thought after the fact that they could have relied on other distinctions in order to defend their claims is irrelevant and speculative. . . . ). Accordingly, we hold that prosecution history estoppel bars IR from asserting infringement of the adjoining limitation under the doctrine of equivalents, and we reverse the district court's entry of judgment as to the adjoining claims.