Prior Art Defense in Patent Infringement Disputes

Prior Art (“PA”) defense is one of defenses in patent infringement disputes. It’s claimed by the defendant with regard to plaintiff’s claim of cessation of the infringement, compensation for damages, which aims at affirming the legality of defendant’s act, rather than denying the novelty of the patent or its scope of protection. In short, it functions as a veto of infringement.

According to Article 22 of Patent Law (revised vision of 2008), the term “PA” refers to the technologies known to the general public both domestic and foreign prior to the date of application. Thus the judge of PA involves two elements: (1) time. Be prior to the date of application; (2) disclosure. It has been publicly disclosed in domestic or foreign publications or has been publicly used or made known to the public by any other means. However, when any alleged infringers are justified of their defense of prior use, other defendants still can’t claim for PA defense on it as they have to provide evidence that it has been publicly disclosed.

In judicial practice, there exists many issues concerning whether the PA defense can be justified. We’ll discuss on two of them below.
Firstly, can PA defense be applied in “literal Infringement”?

Opinion of Beijing Higher People’s Court on Several Issues Concerning the Infringement Determination of Patent (Trial, 2001) limits PA defense within “Infringement under the Doctrine of Equivalents”, and excludes its application in “literal Infringement”. But in the judgment of Gao Min Zhong, No. 571, 2006, Beijing Higher People’s Court points out that although the allegedly infringing product falls within the plaintiff’s scope of patent protection, and constitutes “literal Infringement”, its technical solution constitutes “Infringement Under the Doctrine of Equivalents” with PA….the PA defense should be justified. In the notice of disallowing the request for a new trial in case Min 3 Jian, No. 51-1, 2007, the Supreme People’s Court deems that principle of PA defense can also apply to “literal Infringement”. The revised Patent Law (2008) stipulates in Article 62 that, if the accused infringer has evidence to prove that the technology or design he exploits is PA…. It is generally understood that the judge of PA defense needs only to compare the allegedly infringing technology with PA, which means that the application of PA defense is no longer limited to “Infringement under the Doctrine of Equivalents”, but extends to “literal Infringement”. This change is, of course, favorable to the defendant.

Secondly, how to decide whether the allegedly infringing technology belongs to PA?

According to Article 14 of Interpretation of the Supreme People’s Court on Several Issues concerning the Application of Law in the Trial of Patent Infringement Dispute Cases (Fa Shi [2009], No. 21), “if all the alleged technical characteristics that fall within the scope of patent protection, are identical or not substantively different from the corresponding technical characteristics in PA, then people’s court should affirm that the technology implemented by the accused infringer belongs to PA stipulated in Article 62 of Patent Law.” This is the general rule on judging PA currently.

According to this article, two aspects are important on deciding whether the allegedly infringing technology belongs to PA:

1.The allegedly infringing technology is identical or not substantively different from PA. This can be clarified from technical field, technical problems planned to solve, technical solution, aim and effect (similar to requirement of “Infringement under the Doctrine of Equivalents”). It is generally considered that if difference does exist between the two, but yet belongs to “direct replacement of conventional techniques in the field”, it can be affirmed as “not substantively different”. Besides, if the difference belongs to “Widely-known Technology of the specified field”, PA defense shall be justified, as it can come up with technician without creative work. In practice, as there is much controversy in judge of substantive difference in individual cases, the defendant has to enhance his evidence to improve its persuasion.

2.The quoted technical solution is limited to one item. Although the combination of several technical solutions is not acceptable, when “the allegedly infringing technology is a simple combination of PA and “Widely-known Technology of the specified field”, generally PA defense can be justified. (The Speech in 2010.4.28 by the Vice-President of the Supreme People’s Court Xiaoming Xi on Symposium of Judicial Work of Courts Nationwide on Intellectual Property Case; and Guidelines of Shanghai Higher People’s Court on Trial of Patent Infringement Disputes in 2011).

Besides the issues aforementioned, when the defendant claims PA defense, the party has to pay attention to many other issues, such as, the object of such comparison is limited to allegedly infringing technology and PA; or compare whether the alleged technical characteristics falls into the scope of patent protection; and the relationship between PA defense and non-infringement defense, etc. For parties in individual cases, cognition and utilization of rules of PA defense is of great significance to make litigation strategy and arrange specific evidence, and therefore affects the whole case.