Warner-Jenkinson Company, Inc. v. Hilton Davis Chemical Co., 520 U.S. 17 (1997)
案件概述：
均等論( doctrine of equivalents)的設計是為了讓專利範圍不被請求項的文字所綁死，以使專利權人能獲得合理的權利範圍。但在實務上，均等論的不當使用可能讓專利權人獲得過大的範圍，或是造成權利的不確定性，與專利公示(public notice)原則產生衝突。1 因此，如何調和這些衝突便成為法院的重要工作。在本案中，上訴人希望法院能宣告Graver Tank案中所確立的均等論已經實質”死亡”，但最終最高法院確定均等論依舊存在，但也適度限制其適用範圍，例如個別比對的原則及歷史禁反言的適用。
判決重點：
- 均等論依舊存在。2
- 必須就每一要件個別判斷均等(element by element)，，而非就整體發明判斷的整體比對(as a whole)。因為每一個要件對於權利範圍的界定皆是重要的。只要均等論的適用不會廣泛到可以排除某一要件，請求項的核心功能就不會失效。3
- 若均等論會使請求項中的某一要件完全無效，法院應作出部分或全部判決，因為已經沒有進一步的實質問題要給陪審團處理，這也就是新的請求項破壞原則(claim vitiation doctrine)。 4
- 歷史禁反言(Prosecution history estoppel)仍然可以作為侵權的抗辯。若專利權人可證明修改與專利性無關，法院必須判斷歷史禁反言是否適用；若沒有說明原因，法院可假定修改的部分適用歷史禁反言。5
- 訴訟雙方及 CAFC耗費許多經歷討論三部測試法(triple identity test)及非實質差異法(insubstantial differences test)的優劣。最高法院的總結是，三部測試法適用於機械裝置，但常不足以分析其他產品或製程；非實質差異法對於差異是否”非實質”(insubstantial)則沒有提供充分的指引，所以重點是”被控侵權之產品或製程是否包括與請求項中每一個要件相同或均等的元件” 6。SCOTUS無意介入CAFC分析均等的文字使用，並希望CAFC可以在不同判決中完善均等論的判斷框架。
本案歷程：
專利權人(Hilton Davis Chemical)及被告(Warner-Jenkinson)皆為染劑黃色 6 號及紅色 40 號的製造商。相較於傳統的鹽析法，Hilton Davis所研發的超過濾法更加進步，並可得到高純度的染劑。
系爭專利(US4,560,746)為一美國部分連續案(CIP)，於 1985 年公告。主張的權利範圍是以約 5-15 埃孔徑的薄膜，在壓力約 200 至 400p.s.i.g.、pH值約 6.0-9.0 將染劑進行過濾的方法。在申請過程中曾經對權利範圍進行修正(前案US4,189,380 的pH值為 9.0 以上，故’746 專利將pH值限制在 6.0-9.0 之間以與其區隔)。7
Warner-Jenkinson使用的過濾條件與’746 類似，但操作的pH值為 5.0，專利權人承認被告並無文義侵害(literal infringement)，是故主要議題聚焦在均等論上(pH值 9.0 的上限由於禁反言應無均等空間，但pH值 6.0 的下限是否可適用均等論則為爭議點之一)。被告認為pH值 6.0 的下限是為了避免起泡的問題，且此專利方法無法在低於此酸鹼值的環境下操作；專利權人則堅持其方法可以在低至pH2.2 的環境下操作，且不會有起泡的影響，但並未說明當初加入此下限的原因。
一審地院基於均等論判決被告侵權，因為兩者同樣都是使用壓力迫使溶液透過薄膜進行過濾，其間並無實質差異。地院亦對被告發出禁制令；但由於Warner-Jenkinson並非故意侵權，裁定其僅需付出專利權人要求賠償金的 20%。
本案一路上訴至最高法院，最高法院指出請求項中的化學元素與替代元素之間的差別是”似是而非的”，而地院基於均等論所做出的侵權判決是正確的。8 但由於專利權人並沒有說明為什麼加入pH值 6.0 下限的限制，法院不可能得知此修改是否可避免造成禁反言，再加上CAFC對於均等論的判斷並未符合最高法院的解釋，因此將本案發還CAFC更審。9
- “There can be no denying that the doctrine of equivalents, when applied broadly, conflicts with the definitional and public notice functions of the statutory claiming requirement.”
- “Today we adhere to the doctrine of equivalents. The determination of equivalence should be applied as an objective inquiry on an element by element basis.”
- “[e]ach element contained in a patent claim is deemed aterial to defining the scope of the patented invention, . . . the doctrine of equivalents must be applied to individual elements of the claim, not to the invention as a whole.”
- “if a theory of equivalence would entirely vitiate a particular claim element, partial or complete judgment should be rendered by the court, as there would be no further material issue for the jury.”
- “Prosecution history estoppel continues to be available as a defense to infringement, but if the patent holder demonstrates that an amendment required during prosecution had a purpose unrelated to patentability, a court must consider that purpose in order to decide whether an estoppel is precluded. Where the patent holder is unable to establish such a purpose, a court should presume that the purpose behind the required amendment is such that prosecution history estoppel would apply.”
- “Does the accused product or process contain elements identical or equivalent to each claimed element of the patented invention?”
- 獨立項 1：In a process for the purification of a dye selected from the group consisting of the disodium salt of 1-[(6-methoxy-4-sulfo-3-methylphenyl)azo]-2-naphthol-6-sulfonic acid, the disodium salt of 1-[(4-sulfophenyl)azo]-2-naphthol-6-sulfonic acid, the trisodium salt of 1-[1-(4-sulfonaphthyl)azo]-2-naphthol-3,6-disulfonic acid, the disodium salt of 2-[1-(4-sulfonaphthyl)azo]-1-naphthol-4-sulfonic acid and the sodium salt of 2-(2-quinolyl)-1,3-indanedione-sulfonic acid as the products resulting, respectively, from the diazotization of 5-methoxy-2-methylsulfanilic acid in water with sodium nitrite in the presence of hydrochloric acid followed by the coupling under alkaline conditions of the resulting 5-methoxy-4-sulfo-2-methylphenyldiazonium chloride with sodium 2-naphthol-6-sulfonate; the diazotization of sulfanilic acid in water with sodium nitrite in the presence of hydrochloric acid followed by the coupling under alkaline conditions of the resulting 4-sulfophenyldiazonium chloride with sodium 2-naphthol-6-sulfonate; the diazotization of 4-aminonaphthalene-1-sulfonic acid in water with sodium nitrite in the presence of hydrochloric acid followed by the coupling under alkaline conditions of the resulting 1-sulfonaphthyl-4-diazonium chloride with disodium 2-naphthol-3,6-disulfonate; the diazotization of 4-aminonaphthalene-1-sulfonic acid in water with sodium nitrite in the presence of hydrochloric acid followed by the coupling under alkaline conditions of the resulting 1-sulfonaphthyl-4-diazonium chloride with sodium 1-naphthol-4-sulfonate; and the condensation of 2-quinaldine with phthalic anhydride followed by sulfonation of the resulting 2-(2-quinolyl)-1,3-indanedione, said dye being present in the resulting reaction mixtures, along with impurities, the improvement which comprises: subjecting an aqueous solution of the reaction mixture resulting from said coupling or said sulfonation to ultrafiltration through a membrane having a nominal pore diameter of 5-15 Angstroms under a hydrostatic pressure of approximately 200 to 400 p.s.i.g., at a pH from approximately 6.0 to 9.0, to thereby cause separation of said impurities from said dye, said impurities of a molecular size smaller than the nominal pore diameter passing into the permeate on the downstream side of said membrane and said dye remaining in the concentrate, and when substantially all said impurities have been removed from said concentrate, as evidenced by their essential absence in said permeate, recovering said dye, in approximately 90% purity from said concentrate by evaporation of said concentrate to dryness.
- “Considering those factors, the Court viewed the difference between the chemical element claimed in the patent and the substitute element to be “colorable only,” and concluded that the trial court’s judgment of infringement under the doctrine of equivalents was proper.”
- “Because the Court of Appeals for the Federal Circuit did not consider all of the requirements as described by us today, particularly as related to prosecution history estoppel and the preservation of some meaning for each element in a claim, we reverse its judgment and remand the case for further proceedings consistent with this opinion.”