Chapter §16.04 Reverse Doctrine of Equivalents

• Jurisdiction: United States

§16.04 Reverse Doctrine of Equivalents

The "wholesome realism" of the doctrine of equivalents, as the Supreme Court euphemistically termed it in Graver Tank & Mfg. Co. v. Linde Air Prods. Co.,¹³⁸ is that the doctrine, which is almost always asserted in its conventional (or "forward") formulation to benefit a patent owner by expanding the scope of exclusive rights beyond those literally encompassed by the patent claims, also can operate (at least theoretically) in "reverse" to assist an accused infringer.

The reverse doctrine of equivalents acts as a defense to a charge of literal infringement.¹³⁹ The doctrine absolves an accused infringer from infringement liability when the accused device, although literally falling within the scope of an asserted patent claim, is so far changed in principle from the claimed invention that a finding of liability cannot be justified as a policy matter.¹⁴⁰ The reverse doctrine of equivalents is "equitably applied based upon underlying questions of fact."¹⁴¹ It seeks "to prevent unwanted extension of the claims beyond a fair scope of the patentee's invention."¹⁴² The reverse doctrine applies "when the accused infringer proves that, despite the asserted claims literally reading on the accused device, 'it has been so changed that it is no longer the same invention.' "¹⁴³

Despite attracting favorable academic attention,¹⁴⁴ courts have rarely applied the reverse doctrine of equivalents to excuse liability.¹⁴⁵ For example, in Roche Palo Alto LLC v. Apotex, Inc., the Federal Circuit observed that application of the doctrine is "rare[]" and emphasized that the Federal Circuit "has never affirmed a finding of non-infringement under the reverse doctrine of equivalents."¹⁴⁶ In 2009 the Federal Circuit stated that "[b]ecause the reverse doctrine of equivalents requires a fundamental change in the basic principle by which the device operates, the doctrine is rarely invoked and virtually never sustained."¹⁴⁷

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Notes:

^[138] 339 U.S. 605, 608 (1950) (stating that "[t]he wholesome realism of this doctrine is not always applied in favor of a patentee but is sometimes used against him").

^[139] See Graver Tank, 309 U.S. at 608–609 ("where a device is so far changed in principle from a patented article that it performs the same or similar function in a substantially different way, but nevertheless falls within the literal words of the claim, the doctrine of equivalents may be used to restrict the claim and defeat the patentee's action for...