[When a patent issues] with its terminal disclaimer in effect, that disclaimer [becomes part of the "original patent" for purposes of 35 U.S.C. § 251 and serves] to define its term, regardless of any further term that might have been otherwise available in the absence of the disclaimer.

On December 6, 2012, in In re Yamazaki, the U.S. Court of Appeals for the Federal Circuit (Lourie,* Reyna, Krieger) affirmed the USPTO Board of Patent Appeals and Interferences decision upholding the patent examiner's rejection of U.S. reissue application No. 10/045.902 (seeking reissue of U.S. Patent No. 6,180,991), which related to an improved semiconductor having low phosphorus concentration, for lack of error correctable under 35 U.S.C. § 251. During the prosecution of the application that resulted in the '991 patent, a terminal disclaimer to Yamazaki's earlier-issued U.S. Patent No. 4,581,476 was filed to overcome an obviousness-type double patenting rejection. The Federal Circuit stated:

Yamazaki contends that the Board erred in rejecting his reissue application for failure to state an error correctable by reissue under § 251. Specifically, Yamazaki points to errors of his own and of the PTO that, by allowing the '991 patent to issue with the Petition to Withdraw still pending, see supra note 1, rendered the '991 patent wholly or partially inoperative and caused him to claim less than he was entitled to by unnecessarily disclaiming part of the '991 patent's full term. Yamazaki argues further that "the term of the original patent," as used in § 251, refers to the maximum statutory grant of exclusivity under 35 U.S.C. § 154(a), which provides that "such grant shall be for a term beginning on the date on which the patent issues and ending 20 years from the date on which the application for the patent was filed." According to Yamazaki, a terminal disclaimer does not alter that statutorily defined term but merely adjusts the patent's expiration date without altering the statutory term itself. Yamazaki thus maintains that any disclaimed portion of the base statutory term remains available and subject to reissue as part of the "term of the original patent" specified in § 251.

The PTO counters that once a patent has issued, a recorded terminal disclaimer becomes part of the original patent and defines its term, so that the patent must be treated as if the disclaimed term never existed. In the PTO's view, Yamazaki's request to reissue the '991 patent without its terminal disclaimer would thus violate § 251 by expanding the term of the reissue beyond "the term of the original patent." In the alternative, the PTO contends that § 251 also precludes Yamazaki's reissue request because no "unexpired part of the term of the original patent" remains, the '991 patent having expired with the '476 patent in 2003.

The parties thus agree that the "term of the original patent" defines the outer limit of the PTO's reissue authority under § 251, i.e., the term of a reissued patent may not extend beyond that of the original. We therefore must determine the effect of Yamazaki's terminal disclaimer on the term of the original '991 patent for purposes of § 251. If, as Yamazaki argues, the terminal disclaimer merely shifted the '991 patent's expiration date within an "absolute" statutory term that extends to 2018, the PTO could reset the expiration date anywhere within that term through reissue without exceeding the term of the original '991 patent. On the other hand, if the terminal disclaimer defined the original '991 patent's term based on the expiration date of the '476 patent, any reissue of the '991 patent would be confined to that reduced term under § 251. We agree with the PTO and conclude that when the '991 patent issued with its terminal disclaimer in effect, that disclaimer became part of the original '991 patent and served to define its term, regardless of any further term that might have been otherwise available in the absence of the disclaimer.

To examine the effect of a terminal disclaimer on the term of an original patent, we turn first to 35 U.S.C. § 253, which governs both terminal disclaimers and subject-matter disclaimers. . . . Two aspects of § 253 are important to our analysis. First, the statute dictates that a terminal disclaimer is treated as part of the original patent -- the same benchmark used to fix the maximum term for reissued patents in § 251. More specifically, § 253 describes terminal disclaimers and disclaimers of patent claims in parallel, first describing subject-matter disclaimers and then instructing that terminal disclaimers operate "[i]n like manner." Section 253 thus indicates that the provisions describing disclaimers of patent claims -- including that such disclaimers "shall thereafter be considered as part of the original patent" -- apply with equal force to disclaimers of patent term. As such, it is apparent that a terminal disclaimer's effects on patent term, whatever those effects might be, must apply to "the term of the original patent" as recited in § 251.

Next, because the disclaimer of any issued claim inheres in the original patent, we have interpreted § 253 to mean that after such disclaimer "the patent is treated as though the disclaimed claims never existed." We conclude that the same holds true for Yamazaki's disclaimer of patent term. If a patentee's post-hoc disclaimer of an issued patent claim applies as part of the "original patent" such that the disclaimed subject matter is treated as if it never existed, we see little reason why a terminal disclaimer filed before the issue date should not be afforded the same effect.

Our conclusion finds added support in other provisions of the Patent Act relating to patent term. For example, 35 U.S.C. §§ 155, 155A, and 156 codify additional mechanisms for varying the "term" of an "original patent" relative to that provided under § 154(a). To be sure, § 154(a) establishes a baseline term for original U.S. Patents, but Yamazaki's contention that § 154(a) provides the sole basis for defining the "term" of a patent is undermined by the appearance of the same language in other statutes. Had Congress intended to distinguish the concept of patent "term" established in § 154(a) from the mechanisms for adjustment provided under §§ 155, 155A, 156, and 253, it surely could have done so-for example, by casting the latter statutes as affecting the expiration date rather than the term of affected patents. Instead, each of those statutes, like § 251, uses the word "term." To hold that § 251 uses "term" in a sense consistent with § 154(a) but distinct from §§ 155, 155A, 156, and 253 would be to endorse an untenable reading of the statutory scheme, which we decline to do.

We thus cannot agree with Yamazaki's view of patent term as an absolute, immutable statutory grant under § 154(a) -- patent term calculations begin but do not necessarily end with that section. Various statutory devices, including a recorded terminal disclaimer, can redefine the term of an original patent. When a patent issues subject to a terminal disclaimer, the patentee therefore has not just agreed to forgo some amount of its enforceable term, but has in fact reduced the term itself by effectively eliminating the disclaimed portion from the original patent. Accordingly, Yamazaki's terminal disclaimer eliminated any term from the original '991 patent beyond December 22, 2003. The intended and undisputed language of the terminal disclaimer tied the original term of the '991 patent to that of the commonly owned '476 patent, and there is no question that the '476 patent lawfully expired in 2003. Given the '991 patent's truncated term, the Board correctly recognized that reissue "never existed as a remedy to withdraw the terminal disclaimer." Once the '991 patent issued with the terminal disclaimer in place, and the terminal disclaimer consequently became part of the original patent, the PTO was foreclosed from later reissuing the patent for a term greater than that of the original '991 patent -- in this case, for a term extending beyond December 22, 2003. Yet that is precisely the result Yamazaki sought to achieve. The PTO thus had no choice but to reject the Reissue Application, as the alternative would have contravened the express conditions of § 251.