No doubt that the rules of patent claim construction are drawn heavily from the rules for construing contract and statutory provisions. Words cannot be ignored, each term has meaning, both as a word and in the context of the whole. Does this apply or not to interpreting the statute on certificates of correction.
In CAPS v. Advanced Cardiac, (CAFC 04/03/07), the panel put its gloss on the statutory terms, then recast the statutory standard, to invalidate a duly-granted certificate correcting what might well have been a typo. The statute, §255, encompasses mistakes in issued patents of a clerical or typographical nature, or of minor character. Use of or in the statute might be construed as separating disjunctive terms, to mean either a typographical mistake of the applicant, or a mistake of minor character. The CAFC interpreted the statute to reach only mistakes that are both typographical and not minor.
The CAPS patent used the term osmolarity instead of osmolality. The patent office granted the correction, apparently having applied the statute to what was either a good faith mistake of a clerical or typographical nature, or [a mistake] of minor character. Although the mistake did not need be both typographical and minor, it was one letter different, and the correction caused a minor broadening of the literal range of a claimed element.
The Federal Circuit either fused the minor character and the no new matter aspects in the statute into an overarching requirement, or it ignored one of those two separte aspects in favor of a standard nowhere stated in the statute. Instead of ascertaining the sort of mistake, and that it occurred in good faith, and that correcting it would not introduce new matter or require reexamination, the CAFC applied its own standards. First, they adopt typographical mistakes as a legal issue of claim interpretation (not a matter decided administratively by the Patent Office), and they measure it from what hypothetically is clearly evident to one of skill in the art (without a statutory basis).
Had the Congress wanted the statute to require typographical and minor mistakes, and intended for the §103(a) or §112 skill in the art standards to apply, then the statute would state as much. Whether a correction would have been clearly evident, whether there is clear and convincing reason to invalidate it, whether issuance by the patent office should be reviewed for clear error or for substantial evidence, are all clearly known and knowable to the Federal Circuit, exclusively. This is another instance where all the work done in the patent office and the district court, applying the clear terms of a statute, are needless, since only the CAFC can decide these matters de novo.