Cross-Purpose Prior Art and Obviousness

While prosecuting a patent application before the USPTO, an Examiner may reject the application's claims as obvious under 35 U.S.C. § 103. A claim is obvious if the differences between it and the prior art are such that the claimed invention would have been obvious to a person of ordinary skill in the art (POSITA) at the time of the invention. The Examiner may base an obviousness rejection on either the combination of prior art references and by modifying the references or their resulting combination.

However, the Examiner must identify a reason or rationale for why combining or modifying the identified prior art references would have been obvious to the POSITA, the rationale being based on the references themselves or general knowledge in the field of the claimed invention.

The Examiner's rationale for combining or modifying the identified references must be grounded in those references or common knowledge. However, that rationale does not have to be the same as the motivation that led the inventor to the claimed combination. According to MPEP 2144.IV, "[t]he reason or motivation to modify the references may often suggest what the inventor has done, but for a different purpose or to solve a different problem," and "[i]t is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant."

For example, if an invention combines elements disclosed in two different references to achieve a particular benefit not acknowledged in those references, the Examiner may still make an obviousness-based rejection by asserting that it would have been obvious for a person of ordinary skill in the art (POSITA) to combine the two references for a different reason than the inventor's original reason for combining the disclosed elements.

However, a recent ruling by the Patent Trial and Appeal Board (PTAB) provides insight into a limitation on the Examiner's stated reasoning when the invention and the cited prior art references operate at cross-purposes.

In U.S. Application No. 15/759,234 ("234 Application"), representative independent claim 1 recites:

1. A sensor sheet for biological information measurement, the sensor sheet comprising:

a first adhesive sheet to be applied to a skin of a subject;

a second adhesive sheet to be stuck to a front surface of the first sheet; and

an electrical circuit comprising a plurality of electrodes and wires connected to the plurality of electrodes, the electric circuit provided in an area in the second adhesive sheet, wherein,

the second adhesive sheet is thicker than the first adhesive sheet,

the first adhesive sheet is higher in stretchability than the second adhesive sheet,

the stretchability of a peripheral edge area of the second adhesive sheet is higher than of a center area of the second adhesive sheet, and

the second adhesive sheet comprising slits extending to a peripheral edge of the second adhesive sheet.

During the prosecution of the 234 application, the Examiner rejected all the claims as obvious based on a combination of four references. Specifically, in the final office action, the Examiner cited Patent No. 5,438,984 to Schoendorfer, as disclosing the slits along the peripheral edge of the second sheet recited in independent claim 1. The Applicant appealed.

In the Appeal Brief, the Appellant claimed that the slits described in independent claim 1 function to minimize the difference in "stretchability" between the first and second sheets, thereby making it more difficult to separate the sheets. This differs from the slits disclosed in Schoendorfer, which, according to the Appellant, are intended to make the adhesive sheet easier to tear off. Consequently, the Appellant argues that the Examiner's combination of prior art references, including Schoendorfer, does not disclose the second (upper) adhesive sheet of independent claim 1.

The Examiner justified the proposed combination of references, including Schoendorfer, by stating a need to determine whether the wearer has likely tampered with the second (outer) adhesive sheet. In response to the Appellant's argument, the Examiner explains that Schoendorfer is a secondary reference used only to modify the second adhesive sheet disclosed by the primary reference for slits and that the entirety of Schoendorfer's disclosed sheet is not to be incorporated into the proposed combination.

In its decision, the Patent Trial and Appeal Board (Board) noted that there must be some form of motivation shown from a reliable source to explain why a person with ordinary skill in the relevant field would have thought of combining two or more references or modifying one to achieve the claimed invention. Keeping this requirement in mind, the Board held that a person of ordinary skill in the art would not have had the necessary motivation to combine the prior art in the manner proposed by the Examiner.

Specifically, the Board noted that "the slits of Appellant's invention and Schoendorfer operate at cross-purposes to each other." (emphasis added). As a result, it "makes Schoendorfer an unlikely reference to combine with Examiner's other applied art to achieve the claimed invention." The Board reaffirmed these cross-purposes as Appellant's use of slits to moderate a sharp stretchability change to prevent the upper sheet from coming off of the lower sheet and Schoendorfer's use of slits to facilitate tearing upon removal in the context of conducting drug testing.

Concerning the Examiner's rationale for combining the cited references, the Board stated that they "are not persuaded that a person of ordinary skill in eth art, in designing a biological sensor, would have any need or motivation to put slits in the peripheral edge to prevent a wearer from tampering with the sensor," especially since such tampering would be detected from an analysis of the captured data.

Given these findings, the Board held that a preponderance of the evidence does not support the Examiner's motivation to combine and, as such, the rejection of independent claim 1 is not sustained.

Clearly, it is a good idea to include a discussion in the specification of the purpose of each element recited in the claims. Notably, the purpose of the slits in the application is not recited in the claim itself. However, sufficient discussion in the specification provided the necessary preponderance of the evidence to support an argument against the appropriateness of the Examiner's motivation to combine the cited references.

Moreover, it is notable that the stated operative purpose is to influence another structural limitation recited in the claim. Specifically, the slits operate to reduce the claimed difference in stretchability between the first and second sheets. This interdependence between claimed limitations makes the disclosed purposes much more effective in combating a motive to combine references that seem to counter the invention's operative purpose.

If you need assistance preparing a response to an obviousness rejection or with any other patent issue, please contact TCP Law at info@tcplawfirm.com or 917-612-1059.