July 30, 2021by Yanhong Hu1

What does “up to at least 150 volts” mean? Does it mean 150 volts is a maximum voltage due to the use of the words “up to” or a minimum voltage due to the use of the words “at least”? This was the problem the Patent Trial and Appeal Board (“Board”) in Ex parte Bagehorn (Appeal 2020-004760) had to solve.

Claim 1 was the sole independent claim on appeal and was directed to a method for the electrolytic polishing of a metallic substrate. The claimed method included a step of “applying a current at a voltage of 270 to 315 volts.”

The Examiner rejected claim 1 as obvious over Clasquin in view of Kodera. Regarding the claimed voltage of “270 to 315 volts,” the Examiner believed Clasquin described an overlapping voltage range based on Clasquin’s disclosure in ¶ 49 that “it has been found that higher voltage up to at least 150 volts can be used.” The Examiner interpreted the phrase “up to at least 150 volts” as teaching a range of “at least 150 volts” and pointed to Clasquin’s disclosure in ¶ 63 that “[c]urrent densities as high as at least 225,000 A/m2 can be used at applied voltages of 150 volts or more” for “nickel based alloy 718” as a support.

Appellant argued the Examiner’s interpretation of the phrase indicated that he ignored the preceding words “up to” and failed to read Clasquin’s disclosure in ¶¶ 49 and 63 in the context of Clasquin as a whole. In particular, Appellant argued “up to at least 150 volts” implied a ceiling of 150V, while the words “at least” provided some flexibility to that ceiling so that Clasquin suggested a maximum voltage that is slightly higher than 150V, but not as high as the lower boundary of 270V recited by claim 1. Appellant further argued that the disclosure in ¶ 49 served as an umbrella disclosure and that Clasquin’s specific working examples, including ¶ 63, would be understood by a skilled artisan as falling within that umbrella. In addition, Appellant noted Table 5 of Clasquin, which disclosed more than two dozen examples, used a maximum voltage of 150V.

The Board sided with the Appellant. The Board agreed that the Examiner’s interpretation of the phrase did not adequately account for the words “up to,” which, by their plain meaning, suggested a maximum, not a minimum. The Board noted Clasquin disclosed in ¶ 49 that for certain metals, polishing with voltages above 40V was undesirable because voltages above 40V resulted in loss of luster; however, certain other metals did not demonstrate the same problem and it was for those metals that “higher voltages up to at least 150 volts can be used.” Therefore, the Board held that, in context, the words “at least” did not wholly negate the preceding words “up to” but rather suggested the ceiling indicated by the words “up to” may be somewhat higher than 150V. The Board agreed with the Appellant that this interpretation was supported by the examples disclosed in Table 5 of Clasquin and was consistent with Clasquin’s other disclosures in, for example, ¶¶ 57 and 95.

Regarding Clasquin’s disclosure in ¶ 63, the Board noted “150 volts or more” – in isolation – was consistent with the Examiner’s understanding of Clasquin. However, the Board found that when it was read in view of Clasquin’s other disclosures, a skilled artisan would not have understood ¶ 63 as suggesting that any voltage above 150V could be used even for nickel 718, as evidenced by the dozen nickel 718 based compositions disclosed in Table 5, for which voltages only ranged from 9.7V to 150V.

Therefore, the Board agreed with the Appellant and found Clasquin as a whole as suggesting a voltage ceiling of approximately 150V, with some flexibility. Because 270V, the recited lower boundary of the voltage range, was 80% greater than the 150V suggested by Clasquin and because the Examiner did not establish a person of ordinary skill in the art would have understood Clasquin as teaching or suggesting voltages as high as those of claim 1, the Board reversed the Examiner’s obviousness rejection.

Takeaway:  Although the term at issue in Bagehorn is not a claim term but a phrase in a cited reference, the interpretation principle is the same. That is, terms and phrases should be given the interpretation as understood by a person of ordinary skill in the art in light of the disclosure as a whole. Nevertheless, the confusion could have been avoided if a phrase such as “up to around 150 volts” had used instead of “up to at least 150 volts.”

Judges:  J. C. Housel, C. C. Kennedy, and J. E. Inglese

by Yanhong Hu

Yanhong (Claire) Hu, Ph.D., is a patent attorney and partner at Element IP. She is active in patent preparation and prosecution, post-grant proceedings, and legal opinions and counseling. Her knowledge and experience in a wide variety of technical fields, combined with her legal expertise, allow her to appreciate various technologies to successfully and efficiently assist her clients.