Baker Hostetler Patent Watch: In re Hyon

Alerts / May 29, 2012

[The Board may select] an element emphasized by the reference, relying on the reference's suggestion that the selected element was responsible for the improved properties [to gain a] full appreciation of what such reference fairly suggests to one of ordinary skill in the art.

On May 24, 2012, in In re Hyon, the U.S. Court of Appeals for the Federal Circuit (Newman, Bryson,* Fogel) affirmed the USPTO Board of Patent Appeals and Interferences decision upholding the patent examiner's rejection of the claims in U.S. patent application Serial No. 10/643,674 (a reissue of U.S. Patent No. 6,168,626), which related to ultra high molecular weight polyethylene (UHMWPE) for artificial joints, as obvious over U.S. Patent No. 5,030,402 (Zachariades) in view of U.S. Patent No. 3,886,056 (Kitamaru). The Federal Circuit stated:

Hyon argues that one of ordinary skill in the art would not be motivated to combine the references because Zachariades is directed to artificial joints whereas Kitamaru is directed to films or sheets, which Hyon contends represent "fundamentally different material technologies." As noted above, however, both Zachariades and Kitamaru pertain to UHMWPE. Although Zachariades primarily contemplates the use of the polyethylene for artificial joints, it generically discloses "a method for producing an UHMWPE product with enhanced planar mechanical properties." Similarly, although Kitamaru primarily contemplates the use of the polyethylene to generate films and sheets, it generically discloses a "process for producing a high melting temperature polyethylene." Neither reference limits the structure of the UHMWPE product that can be made; artificial joints (Zachariades) and sheets (Kitamaru) are simply embodiments of the polyethylene made by each process. Moreover, the distinction between the final products described in the two references is not as great as Hyon suggests. As the Board noted, Zachariades states that its recited method can be used to create thin products, and discusses products that are "transparent." Accordingly, the Board's conclusion that the references both teach processes directed to making the same class of products is supported by substantial evidence, as is its determination that differences in the UHMWPE products described by the embodiments do not negate the motivation to combine the references.

Substantial evidence also supports the Board's determination that the fact that Zachariades teaches crosslinking after molding does not affect the motivation to combine. Zachariades does not state that UHMWPE products can be made only by crosslinking after compression deformation, nor does it state or suggest that faulty or inferior products will result from crosslinking prior to compression. The Board found that "Kitamaru teaches benefits of . . . crosslinking before deformation of the UHMWPE." It also found that "Kitamaru focuses on crosslinking prior to extending as the reason for providing the improved properties," and that "the art provides the focus on using the crosslinking step prior to molding." As noted above, Kitamaru teaches that its method results in a product that has a higher melting or softening point, improved transparency, and excellent dimensional stability.

For similar reasons, Hyon's argument that the Board improperly relied on the arbitrary selection of a single feature from Kitamaru (pre-compression crosslinking) while ignoring the other features is not persuasive. [T]he Board did not take the teachings of Kitamaru in isolation or out of context. As noted above, the Board found that one of skill in the art would appreciate that the pre-compression crosslinking step could be combined with Zachariades to obtain beneficial results. Both references involve similarly structured UHMWPE, and Zachariades does not disparage pre-compression crosslinking. Kitamaru expressly notes that crosslinking to improve the properties of UHMWPE was known in the art, but that the prior art methods did not result in increased melting point or improved transparency. Kitamaru teaches that its method results in a product with those improved properties. In addition, as found by the Board, Kitamaru "focuses on crosslinking prior to extending as the reason for providing the improved properties." Accordingly, it is clear that the examiner and the Board selected the pre-compression crosslinking step because Kitamaru indicated that pre-compression crosslinking was responsible for the improved properties. Given Kitamaru's discussion of crosslinking in the prior art and its focus on pre-compression crosslinking as a reason for the improved properties of polyethylene produced using its method, we cannot say that the Board "exclud[ed] . . . other parts [of the reference] necessary to the full appreciation of what such reference fairly suggests to one of ordinary skill in the art." The Board merely selected an element emphasized by the reference, relying on the reference's suggestion that the selected element was responsible for the improved properties. Considering the references as a whole, as required by Wesslau, we conclude that the Board's determination regarding motivation to combine is supported by substantial evidence.

Finally, substantial evidence supports the Board's determination that Zachariades teaches post-processing to form a final component, as required by claim 84 of the reissue application. For example, Zachariades states that "[t]he product is simultaneously shaped into the final product"; that the compression-deformed product "can be cut off by stamping or other process"; and that "the so-produced solid-state deformed UHMWPE can be used as a precursor for its machining into a final product." Those statements are sufficient to support the Board's finding that Zachariades teaches post-processing to form a final component.

In sum, substantial evidence supports the Board's finding that a person of ordinary skill in the art would have been motivated to combine the early crosslinking step of Kitamaru with the process of Zachariades to obtain the enhanced properties disclosed by Kitamaru that result from crosslinking prior to deformation. We therefore affirm the Board's determination that the reissue claims would have been obvious in light of the prior art. Accordingly, we need not address whether the reissue claims impermissibly sought to recapture subject matter surrendered during the original prosecution in violation of 35 U.S.C. § 251.

If you have questions about the material presented above, please contact Dr. Lawrence M. Sung (lsung@bakerlaw.com or 202.861.1537) or any member of our Intellectual Property Team.

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