(1) In terms of prosecution history estoppel, although a prosecution disclaimer requires “clear and unambiguous disavowal of claim scope,” the court has recognized that “applicants rarely submit affirmative disclaimers along the lines of ‘I hereby disclaim the following …’ during prosecution and need not do so to meet the applicable standard.” In practice, anything you say can and will be used against you. Further, contrary to the accepted practice in many foreign jurisdictions that do not have prosecution history estoppel, in the U.S. it is generally better to pursue only one line of argument at a time (at least up to the appeal stage) as “an applicant’s argument that a prior art reference is distinguishable on a particular ground can serve as a disclaimer of claim scope even if the applicant distinguishes the reference on other grounds as well.” (2) In terms of means-plus-function claim scope, this case is another reminder that means-plus-function elements are interpreted narrowly as the specific embodiments disclosed in your specification, rather than the broader type of embodiments they may correspond to. “We have held that structure disclosed in the specification is ‘corresponding’ structure only if the specification or prosecution history clearly links or associates that structure to the function recited in the claim. This duty to link or associate structure to function is the quid pro quo for the convenience of employing § 112, ¶ 6.”
Background / Facts: The patent here is directed to treating injured tissues by sequestering particles and macromolecules in a defined space using a selectively permeable barrier. To improve the treatment of complex fracture injuries, the patent discloses “a unique method of fracture stabilization and a means to restrain interfragmentary macromolecules using a single, flexible minimally porous sheet.” Despite statements like this and that “[t]he invention is a unique method … to restrain interfragmentary macromolecules using a single, flexible minimally porous sheet,” the claims make no mention of a “sheet” and recite only generically a “device” that is “capable of substantially restricting the through passage of at least one type of macromolecule therethrough.” Further, despite a similarly narrow description in the specification that mentions only a “hydrolysable bond” to achieve a directional drug release, the claims recite “means for release of an at least one treating material in a directional manner.”
Issue(s): (1) Whether the claim term “device” should be construed broadly to mean any “device having the limitations called out by the body of the claim” as found by the district court. (2) Whether the specification supports the district court’s broad reading of the structure corresponding to the means-plus-function term “release means” as encompassing all “chemical bonds and linkages.”
Holding(s): (1) No. “We conclude that Saffran’s statements during prosecution of the ’760 patent limit ‘device’ to a continuous sheet. On multiple occasions during prosecution, Saffran sought to distinguish prior art by representing to the examiner that ‘[t]he device used is a sheet rather than a pre formed chamber (Gaskill).’” While recognizing that prosecution disclaimer requires a “clear and unambiguous disavowal of claim scope,” the court latched onto the fact that “Saffran’s unqualified assertion that ‘the device used is a sheet’ extends beyond illuminating how the inventor understood the invention … to provide an affirmative definition for the disputed term. Given such definitive statements during prosecution, the interested public was entitled to conclude that the ‘device’ recited in the claims of the ’760 patent is a continuous sheet.” (2) No. “We conclude that although the district court correctly identified the claimed function as ‘to release a drug preferentially toward the damaged tissue,’ it erred in identifying the corresponding structure disclosed in the specification. The claimed structure for the ‘release means’ limitation is correctly construed as a hydrolyzable bond,” rather than encompassing all “chemical bonds and linkages.” “The ’760 patent does not, however, link any additional structures to the release function with sufficient specificity to satisfy § 112, ¶ 6. … No non-hydrolyzable bonds are discussed or suggested. … Accordingly, we are not persuaded that the specification’s scattered use of the generic phrase ‘chemical bonds’ conveys additional, specific corresponding structures separate and apart from hydrolyzable bonds.”