尽管专利权人有时会就其声称的权利要求含义作证，但此类主观的、事后的证词几乎没有分量。事实上，即使权利要求的措辞所表达的并非申请人原本的意图，法院也可能拒绝忽略清晰明确的权利要求语言。例如，某权利要求限定披萨面团在烤箱中加热到 $400-800$ 华氏度，这是一个会让披萨变成焦炭般硬度的温度。专利权人本意是烤箱应达到此高温，而非面团本身。法院拒绝忽略权利要求的措辞，尽管结果十分荒谬：
“我们解释权利要求是依据其所写，而非专利权人希望其所写。”
Sometimes it is difficult to reconcile conflicting evidence on how claim language should be interpreted.For example, the critical term "solder reflow temperature" could have meant the temperature at which solder begins to melt or the higher temperature at which it flows freely. The standard literature in the field supported the former meaning, but the examples disscussed in the patent only seemed consistent with the later. The court had to choose because infringement depended on the proper definition.
有时，对于如何解释权利要求语言，很难调和相互矛盾的证据。例如，关键术语“焊料回流温度”（"solder reflow temperature"）可能指焊料开始熔化的温度，也可能指焊料自由流动的更高温度。该领域内的标准文献支持前一种含义，但专利中讨论的实施例似乎仅与后一种含义一致。由于侵权判定取决于正确的定义，法院必须做出选择。
On various occasions, the Federal Circuit has discussed procedures for weighing conflicting evidence. In Vitronics, the court emphasized "intrinsic" evidence - evidence, that is, found in the patent itself or in the prosecution history. It approved resort to "extrinsic"evidence, like technical dictionaries, only in the rare case that the intrinsic evidence was ambiguious. On the other hand, some later cases -most notably Texas Digital sysyems, Inc. V. Telegenix, Inc.- emphasized the “plain meaning” of claim language, best exemplified by neutral soureces like dictionaries. Following Texas Digital, one might begin the process of claim interpretation with just the kind of extrinsic evidence dismissed in Vitronics.
在不同的案件中，联邦巡回法院（Federal Circuit）对权衡相互矛盾的证据程序进行了讨论。在 Vitronics 案中，法院强调了“内部证据”（intrinsic evidence）——即在专利本身或审查历史中找到的证据。它批准只有在内部证据模棱两可的罕见情况下，才能诉诸“外部证据”（extrinsic evidence），如技术词典。另一方面，一些后来的案件——其中最著名的是 Texas Digital Systems, Inc. V. Telegenix, Inc. 案——强调权利要求语言的“普通含义”，而这最好由像词典这样的中立来源来例证。遵循 Texas Digital 案的思路，权利要求解释程序可以从 Vitronics 案所摈弃的那类外部证据开始。
In Philip V. AWH Corp., the Federal Circuit addressed these contradictions en banc. While the court found the recent emphasis on dictionaries overdone, it refrained from introducing a rigid hierarchy excluding extrinsic evidence in all but the rarest of cases. It admitted that there is "no magic formula or catechism" for construing claim language and no particular sequence of steps that a court must invaribly apply. Rather, one must interpret claim language as it would be understood by persons in the field of the invention, which includes proper regard fro what the patent itself has to say. Extrinsic evidence can be illuminating, but if the patent is perfectly clear one cannot contradict its meaning by resort to other sources of information. In that respect , the court reaffirmed Victronics at the expense of Texas Digital.
在 Philip V. AWH Corp. 案中，联邦巡回法院以全体法官（en banc）的形式审理了这些矛盾。尽管法院认为近期对词典的过度强调并不可取，但它仍未引入僵硬的层级制度，从而避免了在所有情况下（除了最罕见的案例）排除外部证据。它承认，对于解释权利要求语言，“没有万能的公式或教条”，法院也并非必须始终遵循特定的步骤序列。相反，必须根据本领域技术人员的理解来解释权利要求语言，这其中也包括对专利本身内容的适当考量。外部证据可以起到阐明作用，但如果专利内容本身已经非常清晰，则不能通过诉诸其他信息来源来推翻其含义。在这一点上，法院重申了 Vitronics 案的立场，牺牲了 Texas Digital 案的观点。
以上内容来自书 《Patent Law Essential》Fifth edition