Assignor Estoppel Prevents an Inventor From Testifying that the Patent He Assigned Was Invalid

Case: Pandrol v. Airboss Railway Prod. , No. 04-1069 (Fed Cir. 9/19/05)

The One Sentence Summary: The district court properly ruled on summary judgment that (1) the patent satisfied the written description requirement of 35 U.S.C. § 112 because the description showed that the inventor possessed the claimed invention at the time of filing; and (2) the inventor was barred by the assignor estoppel doctrine from testifying that the patent he assigned was invalid.


What They Were Fighting About: On this case's third trip to the Federal Circuit, the Federal Circuit panel affirmed the district court's summary judgment of patent validity. The description adequately disclosed the adhering means for a railroad tie abrasion-resistant plate.

Federal Circuit Holdings:

• The district court correctly ruled that the patent satisfied the written description requirement of 35 U.S.C. § 112 because the original specification (before amendment) showed that the inventor possessed the claimed invention. "A patent specification must contain an adequate written description. 35 U.S.C. § 112, ¶ 1 (1994). In 1967, this court’s predecessor inaugurated use of § 112 to prevent the addition of new matter to claims. In re Ruschig, 379 F.2d 990 (CCPA 1967). Thus, in a recent application of the written description doctrine, this court noted: "The purpose of the written description requirement is to prevent an applicant from later asserting that he invented that which he did not; the applicant for a patent is therefore required ‘to recount his invention in such detail that his future claims can be determined to be encompassed within his original creation.’" Amgen Inc. v. Hoechst Marion Roussel Inc., 314 F.3d 1313, 1330 (Fed. Cir. 2003) (citing Vas-Cath Inc. v. Mahurkar, 935 F.2d 1555, 1561 (Fed. Cir. 1991)).
  Compliance with § 112 requires sufficient information in the specification to show that the inventor possessed the invention at the time of that original disclosure. See Vas-Cath, 935 F.2d at 1561 ("Adequate description of the invention guards against the inventor’s overreaching by insisting that he recount his invention in such detail that his future claims can be determined to be encompassed within his original creation."). The possession test requires assessment from the viewpoint of one of skill in the art. Id. at 1563-64 ("[T]he applicant must . . . convey with reasonable clarity to those skilled in the art that, as of the filing date sought, he or she was in possession of the invention." (emphasis in original)); Union Oil Co. of Cal. v. Atl. Richfield Co., 208 F.3d 989, 997 (Fed. Cir. 2000) ("The written description requirement does not require the applicant ‘to describe exactly the subject matter claimed, [instead] the description must clearly allow persons of ordinary skill in the art to recognize that [the inventor] invented what is claimed.’" (citation omitted))."
• The district court properly applied the doctrine of assignor estoppel to prevent the inventor from testifying that the patent was invalid: "Assignor estoppel is an equitable doctrine that prevents one who has assigned the rights to a patent (or patent application) from later contending that what was assigned is a nullity." Diamond Scientific Co. v. Ambico, Inc., 848 F.2d 1220, 1224 (Fed. Cir. 1988). Thus, an assignor and parties in privity with the assignor are estopped or barred from asserting invalidity defenses. Id. In this case, the district court invoked that doctrine to bar an assignor from testifying against the validity of its own patent. Courts frequently mention four justifications for the doctrine of assignor estoppel: "(1) to prevent unfairness and injustice; (2) to prevent one [from] benefiting from his own wrong; (3) [to adopt the] analogy [of]. . . estoppel by deed in real estate; and (4) [to adopt the] analogy to a landlord-tenant relationship." Id. (quoting Hal Cooper, Estoppel to Challenge Patent Validity: The Case of Private Good Faith vs. Public Policy, 18 Case W. Res. 1122, 1128 (1967))."
• The district court correctly excluded the declaration of Mr. Young, one of the inventors, because he had not submitted an expert report as required by Rule 26(a)(2) of the Federal Rules of Civil Procedure and the declaration included expert opinions.
• The district court properly refused to consider obviousness arguments based upon late-submitted prior art when the proponent had not proposed obviousness jury instructions and had earlier stated that it did not seek a finding of obviousness.