[co-author: Shanji Fang]

Guangzhou Intellectual Property Court has recently made first-instance judgment on an infringement case over 2 patents for invention of zippers where we served as the agent of the plaintiff YKK Co. Ltd. and concluded that the behavior of the defendant, a local company, constituted infringement.

In the above cases, the defendant mainly presented the defense to infringement based on prior use and submitted a large amount of evidential materials including purchase vouchers of relevant machines, sample products as exhibits on exhibitions, and correspondence with customers, and the like, with multiple pieces of notary preserved evidence.

We thoroughly studied the contents and mutual corroboration of the evidence materials, and found out that the evidence submitted by the defendant included merely partial information of the manufacturing equipment and the product, and was silent on the specific technical features defined by the claims of the involved patents and the corresponding relation between the manufacturing equipment and the product. On this basis, we argued that the evidence submitted by the defendant was inadequate to prove that the defendant had already made necessary preparations for making or using the alleged infringing product before the filing date of the patent in dispute. The court agreed and determined that the prior us defense of the defendant could not hold and the defendant infringed the patent right of YKK.

Prior use defense is very common in infringement disputes before court. In the preparation of evidence for prior use defense, consideration should be given from the following perspectives.

1. Evidence for prior use defense not only should meet with statutory and regulatory requirements, but should satisfy the three characteristics of evidence.

Prior use defense in infringement disputes mainly aims to prove implementation prior to the filing date of the involved patent. However, an alleged infringer seldom preserves evidence of use prior to the filing date of the involved patent. It is a rather common case that the alleged infringer only starts to collect evidence of use prior to the filing date upon the occurrence of dispute. Further, the collected evidence is mostly proof of implementation by the unilateral party of the alleged infringer which, without corroboration of third-party evidence or evidence preservation by notarization before the filing date of the involved patent, can hardly be recognized to be effective.

In view of this, in addition to effective security measures, a company may preserve evidence for a technology for which a patent has not yet been applied by notarizing the specific implementation or by other measures, so as to enable appealing for misappropriation of trade secret or defense based on prior use in disputes over patent infringement arising from trade secret leakage or patent enforcement by another company. On the other hand, when disputes arise, if the company does not make effective preservation on the evidence prior to the filing date, the applicant may prepare for example the original blueprint, working process, production record, product test record, and the like. These documents provided solely by the company would be relatively weak, and should be accompanied by supporting documents provided by a third party or an authority or by evidential materials proving that the preserved blueprint has not been altered, forming a complete and credible evidence chain.

In this case, although the defendant submitted multiple pieces of notary preserved evidence including purchase vouchers of relevant machines, sample products as exhibits on exhibitions, and correspondence with customers in order to improve the effectiveness of evidence, the dates of notarization were all later than the filing date of the involved patent. Thus, the evidence, although notarized, cannot verify the implementation prior to the filing date of the involved patent. Further, the email correspondence containing purchase orders were from the memory of a server of the defendant and could be easily altered. Hence, the authenticity of the correspondence was questionable insomuch as the defendant could not provide the original correspondence records.

2. Evidence for implementation prior to filing date

It is desired to prove that, before the filing date of the patent in dispute, the identical product has been made, the identical process has been used or necessary preparations for such making or using has been made.

In practice, it is difficult to provide direct evidence proving that the identical product has been made or the identical process has been used before the filing date of the patent in dispute. Therefore, in most cases, the alleged infringer submits the blueprint of its primary technology or equipment as proof that it has made necessary preparations for its making or using before the filing date. In such case, it is necessary to prove that the submitted design paper or technological file is indeed the primary drawing of the alleged infringing product. That said, if it is evident that the alleged infringer has already arrived at the design of the key part of the alleged infringing product while the rest of the product is formed by generic parts, for example in the case No. 89 ZMZ (2019), the Supreme People’s Court recognized the submitted drawing as the primary technological drawing. As to the equipment, at least evidence of key equipment or primary raw material for making the alleged infringing product should be provided. Purchase of generic devices or generic materials is inadequate to prove that necessary preparations have been made.

In the afore-mentioned case, the defendant submitted the purchase vouchers of equipment to prove that it made necessary preparations before the date of filing. However, the purchased equipment is generic rather than special for producing the alleged infringing product. In order to produce the alleged infringing product, the purchased equipment needs to be subjected to necessary modification and improvement. Therefore, the purchase vouchers submitted by the defendant cannot prove that it has made necessary preparations before the date of filing.

3. The product or method the evidence for prior use defense is directed to should embody the technical features of the alleged infringing product or method.

The product claimed to be made or prepared for making or the method claimed to be used or prepared for using prior to the filing date should be identical or equivalent to the alleged infringing product or method. Determination of identical product should be based on the technical solution directed to the product, regardless of the name and model type of the product. The term “identical product” means that the alleged infringing product and the product that has been made before the filing date of the patent are the same with the patented product, including a case where alleged infringing product and the product that has been made before the filing date are the same product or a case where although alleged infringing product and the product that has been made before the filing date are not the same product, they are essentially the same with the corresponding part of the involved patent; that is, the corresponding technical features of the products are the same or do not differ from each other fundamentally.

It is common in practice that an alleged infringer fails to present a technical solution that is identical to the alleged infringing product, which results in the submitted evidence being denied. In the above case, the defendant submitted the purchase vouchers of manufacturing equipment dated prior to the filing date and correspondence with clients including purchase orders dated prior to the filing date. However, since the evidence did not include disclosure of the technical solution of the alleged infringing product, it was inadequate to prove that the defendant has already arrive at the technical solution directed to the alleged infringing product before the filing date of the involved patent.

4. Evidence of the scope of prior use

Prior use defense is limited to an “original scope”. Implementation beyond the original scope will still be determined as infringing the patent right. The original scope includes the existing production scale or the production scale achievable by the available manufacturing equipment or based on the existing production preparations before the filing date.

In practice, the company may provide evidence of manufacturing equipment and production orders existing before the filing date to prove the original scope. Where the company cannot submit evidence of the precise production scale, in absence of disproof, the court will acknowledge a production scale that is primarily proven not expanded at a high probability. For example, in the case No. 508 ZMZ (2021), the Supreme People’s Court set forth the opinion that it was inappropriate to set a strict bar for the evidence of “original scope”; when the prior user has submitted all available evidence and the submitted evidence primarily prove a reasonable original scope, if the patentee cannot provide disproof to overturn the statement of the prior user, the court should determine that the prior user does not make or use the alleged infringing product/method beyond the original scope.

As shown above, a key to prior use defense is to form a complete evidence chain. The author’s firm, Beijing Wei Chixue Law Firm, has handled dozens of cases involving the evidence preservation for prior use defense. We have effectively defended the interests of our clients by gathering evidence materials in a comprehensive manner in view of the practical prior use.