Brief Introduction

On June 27, 2013, the Jiangsu Province High People’s Court made a final judgment for a patent infringement litigation relating to nickel foam (hereinafter shortened as “nickel foam patent infringement litigation”) [i]. During the first instance, the second instance and the retrial procedure, one of the main controversy focuses lies in: whether the difference of vacuum pressures in 10 times shall be considered as equivalents and equivalent infringement could be constituted accordingly.

The Jiangsu Province High People’s Court held an opinion that, based on the evidences and statements of the two parties during the proceedings, the base vacuum pressure and the operating vacuum pressure in the alleged infringing solution respectively differ from those in the patented solution in a magnitude, i.e., 10 times, they were apparently different values. The two types of vacuum pressures interact on their functions and/or effects in the magnetron sputtering process. It shall not be easily determined that the different base vacuum pressures and operating vacuum pressures could achieve substantially the same effect. The features relating to “base vacuum pressure” and “operating vacuum pressure” in the alleged infringing technical solution are neither identical nor equivalent to the corresponding necessary technical features in the involved patent. Therefore, the alleged infringing technical solution does not fall within the protection scope of the involved patent right and does not infringe the patent right.

With development of technology and raise of legal awareness, the number of literal infringement litigation in which the alleged infringing solution has completely identical features with the involved patent right becomes less, while infringement of similar features takes a majority. Then, how to determine whether similar features are equivalents? We will briefly discuss this question hereinafter.

2.Principle for equivalent infringement judgment

According to the provision of Article 7 of the Interpretation of the Supreme People's Court on Several Issues concerning the Application of Law in the Trial of Patent Infringement Dispute Cases, patent infringement exists where the alleged infringing solution contains technical features identical or equivalent to all the essential technical features described in a claim of a patent. During a patent infringement lawsuit, if the alleged infringing technical solution contains one or more technical features which are neither identical nor equivalent to any essential technical feature of the involved patent claims, it shall be determined that the alleged infringing technical solution does not infringe the patent right.

In addition, according to the provision of Article 17 of the Interpretation of the Supreme People's Court on Several Provisions of Application of Law in the Trial of Patent Disputes, equivalent features refer to those use substantially the same means, perform substantially the same function, produce substantially the same effect as the technical features in the claim of the patent and can be easily contemplated by an ordinarily skilled person in the art without inventive work.

From the above two provisions, it can be seen that equivalent infringement has the following characteristics:

  1. “Equivalent” refers to equivalent of two technical features but not two technical solutions.

According to the provisions of the Interpretations, the prerequisite to infringement determination is that the alleged infringing technical solution contains technical features identical or equivalent to all the essential technical features in a claim of the patent. Thus, if there is one or more technical feature which is neither identical nor equivalent, the infringement shall not be determined. In other words, this provision takes a separate technical feature as a judgment unit. Thus, during the infringement judgment, the two technical solutions to be compared shall be respectively dissected into separate technical features with the same manner and then the technical features are compared one by one. The reason for comparing separate technical features is that: where the whole technical solutions are equivalent, several technical features therein which are neither identical nor equivalent may solve the same problem and achieve the same effect due to their interactions. This will expand the claim coverage of the patentee and damages the public’s benefit. Therefore, the “technical feature equivalent judgment” is a relatively fair manner.

  1. Prerequisites to equivalent technical features

According to the above Interpretations, the equivalent features refer to those use substantially the same means, perform substantially the same function, produce substantially the same effect as the technical features recited in a claim of a patent and can be easily contemplated by an ordinarily skilled person in the art without inventive work.

That is to say, prerequisites to determining equivalent technical features include: three “substantially the same” and one “can be easily contemplated”. This is similar to principles for examining inventive step. But during the judgment of equivalent technical features, comparison of separate features is more emphasized. In other words, if feature A in the alleged infringing solution is obvious as compared with the corresponding feature A’ in the involved patent, and there is merely simple literal modification or equivalent replacement of normal means, the two features shall be determined as equivalents. Otherwise, if the technical feature in the alleged technical solution is non-obvious as compared with the corresponding technical feature in the involved patent, they shall not be determined as equivalents.

In the above-mentioned nickel foam patent infringement litigation, in the patent, the base vacuum pressure is (1.1~4.7) ×10-3 Pa and the operating vacuum pressure is (2.7~4.7) ×10-2 Pa, whereas those in the alleged infringing technical solution are respectively 2×10-2 Pa and (2.0~2.5) ×10-1 Pa. The parameters respectively differ in one magnitude (10 times). In the vacuum sputtering field, approximately 10-time change in pressure shall be considered as an obvious difference.

According to the prior art, the higher the base vacuum pressure, the higher the purity of the sputtering film. Accordingly, requirements such as pressure-resistance ability and sealing performance of the equipment have a corresponding increase. What’s more, since it requires more time to increase the vacuum pressure, the production efficiency may be reduced. The lower the operating vacuum pressure, the more argon is inputted, and the higher the sputtering efficiency gets. Therefore, as to the two types of vacuum pressures with obvious differences, there is no evidence to prove that they will achieve substantially the same sputtering film purity and sputtering efficiency. Further, the obviously different vacuum pressures certainly have different requirements for relevant power source and pressure-resistance equipment. In view of the above, the feature associated with the vacuum pressure in the alleged infringing solution is non-obvious as compared with the corresponding feature in the involved patent. Based on this, the court of final appeal concluded that the two features are not equivalents and the patent right is not infringed.

In addition, as to comparison relating to number ranges, if the number ranges of two solutions have clear endpoints and are obviously different, it should not be easily determined that they are equivalents. This is important information that we get from this case.

Certainly, the association of the equivalent feature judgment with the inventive examination principle may simplify the judgment. But in practice, some other principles shall also be considered to judge whether the features are equivalents, e.g., the principle of estoppel, the principle of prior art defense, so as to accurately determine whether the infringement exists.