美国联邦上诉法院（CAFC）的首席法官Rader在JOHNSON JOHNSTON ASSOCIATES INC v. SERVICE CO INC一案的协同意见中，提出了等同侵权的可预见性限制：专利撰写者理应将申请专利时可以预见的技术方案写在权利要求内，否则不应将其纳入等同保护范围。判决书中认为，可预见性为评估何时应用等同原则设定了客观标准。如果在申请过程中变更是不可预见的，那么专利权人仍然可以获得等同原则的保护。反对意见则认为可预见性与显而易见性接近而令专利权人左右为难。
翻译参见：《北京高级人民法院专利侵权判定指南理解与适用》（ISBN 978-7-5093-5627-2，2014年9月第1版，北京高级人民法院知识产权审判庭编）第220页，原文为： the doctrine of equivalents does not capture subject matter that the patent drafter reasonably could have foreseen during the application process and included in the claims.
原文为： foreseeability sets an objective standard for assessing when to apply the doctrine of equivalents.
原文为：In reaching this result, the court suggested that if variation had been unforeseeable during the application process, the doctrine of equivalents would still have been available to the patentee.
原文提出：Moreover, the concept of foreseeability seems akin to obviousness. Assuming that the concepts are similar, and that foreseeability or obviousness precludes equivalence, would not a plaintiff asserting equivalence have to show that the accused device would not have been obvious, or foreseeable, in order to avoid a finding of nonequivalence? And would not a defendant have to assert that his device was obvious and hence ineligible for equivalence protection in order to escape liability for patent infringement? It seems counterintuitive for a patentee to have to assert that an accused device was nonobvious or for the accused to have to assert that it was obvious. A patentee seeking to establish equivalence wants to show that the accused is merely making a minor variation of his invention, an obvious one, not a nonobvious improvement. One accused of infringement wants to show that he has made an important advance, not that he is a copier, and that his device was obvious over the patented invention, or foreseeable.《北京高级人民法院专利侵权判定指南理解与适用》（ISBN 978-7-5093-5627-2，2014年9月第1版，北京高级人民法院知识产权审判庭编）第220页也提出了类似的观点。
见于专利文件第5栏第5-9行，原文为：While aluminum is currently the preferred material for the substrate, other metals, such as stainless steel or nickel alloys, may be used. In some instances, such as in laminating plastic credit cards, polypropelene can be used.
原文为：1. A component for use in manufacturing articles such as printed circuit boards comprising:
a laminate constructed of a sheet of copper foil which, in a finished printed circuit board, constitutes a functional element and a sheet of aluminum which constitutes a discardable element;
one surface of each of the copper sheet and the aluminum sheet being essentially uncontaminated and engageable with each other at an interface, a band of flexible adhesive joining the uncontaminated surfaces of the sheets together at their borders and defining a substantially uncontaminated central zone inwardly of the edges of the sheets and unjoined at the interface.