Recently, the U.S. Court of Appeals for the Federal Circuit issued an opinion in Sigray, Inc. v. Carl Zeiss X-Ray Microscopy, Inc., No. 23-2211 (May 23, 2025), reviewing a decision by the Patent Trial and Appeal Board concerning the validity of U.S. Patent No. 7,400,704.
The '704 patent claims an X-ray imaging system that incorporates projection magnification to enlarge images generated by X-ray beams. Sigray filed a petition for inter partes review (IPR), challenging all claims of the ‘704 patent based on prior art, specifically the Jorgensen reference. The Board initially found that Sigray demonstrated a reasonable likelihood that at least one claim was unpatentable and instituted the IPR, but it ultimately declined to hold any of the asserted claims unpatentable.
Sigray appealed only with respect to the Board’s determination that claims 1–6 were not unpatentable. In particular, Sigray contested the Board's decision that claims 1, 3, and 4 were not anticipated by the Jorgenson reference and that claims 1–6 were not obvious over Jorgensen, either alone or in combination with other references. Jorgenson describes using an X-ray beam to image rodent organs and references a process known as collimation, which has the potential to reduce beam divergence and, consequently, magnification. There was no dispute that Jorgenson explicitly disclosed all elements of claim 1, except for the projection magnification limitation: “a magnification of the projection X ray stage . . . between 1 and 10 times.”
The Court considered whether Jorgenson inherently disclosed a diverging X-ray beam producing magnifications within the claimed range. The Court noted that the Board impermissibly narrowed the scope of claim 1 in determining that Sigray “fail[ed] to show that the . . . X-ray beam in Jorgensen diverges enough to result in projection magnification ‘between 1 and 10 times’,” implicitly construing “between 1 and 10” to exclude small amounts of magnification. The Board’s narrowing construction and the evidence of some divergence disclosed in Jorgenson led the Court to ultimately reverse the Board's decision concerning the lack of anticipation of claims 1, 3, and 4, finding that Jorgensen disclosed all elements of claim 1 and dependent claims 3 and 4. However, the Court did not make a final determination on the validity of claims 2, 5, and 6, and remanded the case to the Board for further proceedings to assess whether these claims would have been obvious in light of the Court's opinion.
