The principle of reverse equivalence in the determination of patent infringement in the United States is briefly discussed.

The Concept and Nature of 1. Reverse Equivalence Principle

The principle of reverse equivalence (Reverse Doctrine of Equivalents), also known as the principle of reverse equivalence, is a principle of equity established by the Supreme Court of the United States in the judicial practice of patent infringement litigation. Its meaning means that the accused infringing object or method literally falls into the scope of protection of the patent claims, but the accused infringing object or method achieves the same or similar function in a different way in principle compared with the patent claims. In this case, the accused infringing object or method does not constitute infringement of the patent.

As for the nature of this principle, the author thinks that it is a defense means for the accused patent infringer to the same infringement accusation. Specifically, when the plaintiff can prove that the accused infringing object or method falls within the literal scope of the patent claim, that constitutes the same infringement, the defendant can prove by proof that the accused product or method realizes the function of the invention in a substantially different way, which is substantially different from the patent in principle, thus overturning the plaintiff's infringement claim.

The Origin and Development of 2. Reverse Equivalence Principle

It is generally believed that the idea of the principle of reverse equivalence originated in the United States in the case of Boyden Power Brake Co. v. Westinghouse in 1898. Subsequently, the United States Supreme Court decided in 1950 that Graver Tank & Mfg. Co. v. Linde Air Products Co. The principle of reverse equivalence was formally established in the judgment of the case.

In 1869, Westinghouse invented a braking device that uses a central air pressure box to brake the train. A claim of the patent includes a central air pressure box, an auxiliary air pressure box, an air pipe, a brake cylinder, a valve, a piston, etc. Device. In this case, the defendant Boyden's product contains all the components in the plaintiff's patent claims, but the combination method has been greatly improved and a key component has been added to make the train brake device more efficient and faster, adapting to the trend of growing trains in the late 19th century.

The Supreme Court of the United States pointed out in its judgment in this case that even if the alleged infringement is not within the literal scope of the claim, it still constitutes an infringement under certain circumstances. On the contrary, even if the alleged infringement falls into the literal scope of the patent claim, if the alleged infringement has undergone a fundamental change in principle, the alleged infringement is not within the scope of protection of the patent right and does not constitute an infringement of the patent right. In this case, on the surface, Boyden's device contains all the components in the claims, which literally falls into the scope of protection of the Westinghouse patent. However, the specific combination relationship of Boyden's device is essentially different from that of the patent in question, thus making it jump out of the scope of protection of the patent.

1950 Graver Tank & Mfg. Co. v. Linde Air Products Co. The case is another milestone in the history of the development of the principle of reverse equivalence. In this case, the U.S. Supreme Court affirmed the principle of reverse equivalence, finding its role in defending patent infringement and clearly stating that "the principle of equivalence is not always beneficial to the patentee, and sometimes to the detriment of the patentee. When a device is compared with a patent, even if the device falls within the literal scope of the patent claims, but uses substantially different principles and different ways to accomplish the same or similar functions, the accused infringer can still borrow the principle of equivalence to limit the scope of protection of the patent claims and respond to the patentee's infringement allegations." Although the United States Supreme Court still uses the principle of equivalence in its judgment and does not directly introduce the term reverse equivalence, the relationship between the principle of reverse equivalence and the principle of equivalence is clear.

According to the definition of the principle of reverse equivalence and the discussion of the US Supreme Court on the above two cases, the author believes that the application of the principle of reverse equivalence must meet three major requirements, that is, the accused product or method literally falls into the scope of protection of patent claims, there are substantial differences in principle, and achieve the same or similar functions in a substantially different way.

Application of the principle of reverse equivalence in 3.

Tracing back to the reasons for the emergence of the principle of reverse equivalence, the author believes that it is mainly due to the fact that the claim is no longer fully supported by the specification at the time of the alleged infringement, and has become a broader invention than the description of the specification. Among them, there are not only the objective factors of the development of science and technology, but also the human factors of patent writing skills such as the use of functional limited technical characteristics.

In today's era of rapid development of science and technology, new industries continue to rise, new technologies continue to breed, and new achievements continue to emerge, which objectively will lead to the continuous expansion of the literal meaning of patent claims, and even subversive changes. However, the specific technical content recorded in the patent specification may still stay at the technical level at the time of application or the scope of its expansion is not as large as the patent claim, which will cause the literal scope of the claim to be out of line with the specific technical content in the specification and the disconnect will expand over time. Therefore, although the subsequent technology has been fundamentally improved and achieves the same or similar functions in a different manner in principle, it may still fall within the literal scope of the patent claims.

Taking nanotechnology as an example, nanotechnology is not just a reduction in scale. The internal structure, ordering, and interaction of microscopic particles have also undergone fundamental changes compared to macroscopic technology. Imagine that a nano-device in the micro sense falls into the literal scope of a patent in the macro sense, but because the interaction and activity mechanism of micro-particles are quite different from those of the macro world, the designer of the nano-device must consider many characteristics different from those of the macro scale of the material in the design process, and these characteristics will cause significant differences from the previous patent. If, according to the literal meaning of the claim, it is determined that the nano-device infringes the prior patent right of macro-technology, it will greatly affect the enthusiasm of post-technological innovators in the nano-field and is not conducive to the development of science and technology in the nano-field. The principle of reverse equivalence can provide a fair legal shelter for the designers of nanotechnology.

In addition, functional limited technical features have become a trend in patent writing, especially in the field of electricity. Since the writing method of functional limited technical features not only covers the specific implementation methods recorded in the specification, but also covers other methods that can realize the function. Therefore, if the functional limited technical features are used to make the literal scope of the claims exceed the reasonable scope of the technical content recorded in the specification, or when the functional limited technical features are combined with the factors of scientific development, it is also very easy to produce a situation where the literal meaning of the claims is not fully supported by the specification. In this case, when the alleged infringement or method that should not fall within the scope of protection encounters infringement litigation, the principle of reverse equivalence is a better means of defense.