Public use evidence presents difficulties in invalidation proceedings
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Public use evidence presents difficulties in invalidation proceedings


Jun Qiu of Liu Shen & Associates analyses the difficulties of presenting acceptable public use evidence and details the PRB’s requirements for such evidence


In an invalidation proceeding at the China National Intellectual Property Administration (CNIPA), prior art evidence typically includes two forms of evidence: publication evidence and public use evidence. However, public use evidence is much less popular than publication evidence due to difficulties in proving publicness, the publication date and the integrity of the evidence chain. As a result, it is a challenge for practitioners to utilise this type of evidence effectively in China in circumstances where publication evidence is lacking.

Requirements for public use evidence

According to the Guidelines for Examination of the CNIPA, public use evidence must satisfy the following conditions:

  • Public use includes an act of manufacture, use, sale, import, exchange, demonstration, exhibit or giving as a present etc.

  • The publicness of a public act is dependent on public availability of evidence, not actual knowledge of such evidence by the public. Even public production or sales of a product in small quantity can constitute public use. However, technical information about products exchanged in a closed confidential environment which is not available to the public, such as during collaborative development, cannot be considered as an act of public use, no matter the frequency or scale of such an act.

  • Demonstration of a product does not necessarily disclose the structure of a product or composition of a material, but the sale or use of a product or an apparatus can be considered an act of public use for the structure and functions, even if such information could only be extracted by destructive measures.

For example, if an external photo of a product predates the filing date of a patent, claiming detailed internal structure of the product, such a photo alone is not an effective piece of public use evidence, since such a photo does not reveal any internal structural details of the product. However, if such a product was sold to a customer before the filing date of the patent, such an act might be considered as public use evidence, since the product could be subjected to any reverse engineering measures to reveal the information.

In another example of a well-known decision 4W105655 of the Patent Reexamination Board (PRB) in 2007, the petitioner stated that a clinical trial predating the filing date of a pharmaceutical patent should be considered as an act of public use. The PRB disagreed. It held that during the clinical trial, a doctor or a pharmacist administers the medicine to a patient in order to test the effect of the treatment. Based on such a purpose, the doctor or the pharmacist typically does not perform additional tests to obtain structural information about the medicine in addition to the information disclosed in the spec. It is even less likely that the patient under the treatment could perform such a test. Therefore, the clinical trial does not necessarily constitute an act of public use.

In a nutshell, no matter the type of act that discloses the information, an act can only be considered as an act of public use, if the act can make the technical information contained in the patent available to the public. The mere knowledge of existence of such technical information alone does not constitute public use.

Regional restrictions of previous patent law

The Patent Law of China was amended in 2008, changing from a relative novelty standard to an absolute novelty standard. According to the amendment, for any Chinese patents filed before October 1 2009, an act which amounts to public use is restricted to a domestic region. The act must take place within Chinese jurisdiction. However, for Chinese patents filed on or after October 1 2009, there is no regional restriction for public use.

For example, even if a product was sold in a foreign market outside China before the filing date, such evidence cannot be used to nullify a Chinese patent with a similar technical solution and a filing date before October 1 2009.

Practical tips for PRB proceedings

For public use evidence in invalidation proceedings before the PRB, the facts that must be proved include:

  • publicness of the technical solution of the patent; and

  • act of public use predating the filing date of the patent.

In practice, the evidence chains for the above two acts are often broken due to various defects either in individual evidence or in the nexus between different evidence. Therefore, the petitioner needs to be creative in evidence preparation in order to increase the credibility of public use evidence.

The most common scenario in which public use evidence would arise in an invalidation proceeding is when a petitioner claims that a party sold a product containing the technical solution of a targeted patent before the filing date of the patent, and provides the product or the technical drawings bearing the technical solution. In such a case, the facts below need to be proved.

1. Determination of sale date

The petitioner often can find a product labelled with a date. However, such a date on either a nameplate or a tag without clear definition of a sale date cannot be considered a sale date. In most circumstances, it might be a date of manufacture, maintenance or inventory. In such cases, a combination of a dated sale contract and invoice(s) with dates later than the contract date can clearly prove the date of the sale. However, if the contract and invoice are not available, the petitioner would need to look for additional evidence from third parties with credibility, such as the bank or customs. For example, such evidence includes bank transfer vouchers, custom clearance forms, or records from a state certification agency.

2. Determination of sale

The petitioner often provides a sale contract for proving the act of sale. However, if such a contract is only an agreement of intent such as a price agreement, the contract alone cannot prove the actual delivery of the products referenced in the contract. Therefore, the PRB prefers a purchase and sale contract containing details such as specific type, quantity and amount of money, with other complementary evidence such as invoices, receipts and inventory records, as this evidence could form a good evidence chain for proving the act of sale.

3. Consistency between product and product referenced in sale

The petitioner further needs to prove that the product or the drawing embodying the claimed technical solution of the patent is consistent with the products referenced in the evidence for proving the date of sale, such as a sale contract.

If the purchase and sale contract includes a technical drawing of the product, it would be easy for the petitioner to establish the connection. However, in most cases, the petitioner can only provide the product in addition to the evidence, such as invoices or receipts for proving the date of sale. In this case, the petitioner needs to provide further evidence to show that the relevant part of the product sealed up during evidence collection is not changed or substituted when compared with the product at the time of the sale. Such further evidence could be warranty cards free of repair records, a statement from the customer stating the same, or a product that is still sealed from the time of the sale.

4. Reasonable defects in evidence

In some circumstances, the PRB might affirm the public use evidence even if there are some defects in the individual evidence or in the evidence chain.

For example, during evidence collection, there are different evidence sources which might lead to slight differences in product information regarding product details in the evidence chain. For instance, the product model type in the purchase and sale agreement might not be exactly the same as the product model type written in the invoice or labelled in the nameplate of the product. However, as long as this slight difference in details between evidence complies with common commercial practice, the difference will be considered a reasonable defect permitted by the PRB, taking into account the difficulty of obtaining evidence and the degree of collaboration between various parties in commercial practice.

In a nutshell, no matter the type of act that discloses the information, an act can only be considered as an act of public use, if the act can make the technical information contained in the patent available to the public

In another example, for the sale of consumer products, in most cases, the product would not be delivered to the customer with an accompanying drawing showing the technical contents of the product. Most of the customers will not keep the warranty card after the warranty period. In this case, if the petitioner can only provide a product as a piece of public use evidence, it would be difficult for the petitioner to prove that there is no change in the product from the date of the sale until the date of collecting the evidence. In such instances, the petitioner can consider circumstantial evidence which has credibility. For example, the petitioner can obtain multiple products from different geographical locations and different third party sources. Although the petitioner cannot prove directly that the products have not changed since the date of the sale, if all the products from different locations and sources have the same structure, the PRB might reach the conclusion that the products are not likely to have changed since the date of the sale, thereby affirming the authenticity of the public use evidence. The petitioner might also consider seeking a collaborative statement from the customers in order to increase the weight of the proof.

In a further example, a petitioner provides a purchase and sale contract of a product without any technical drawings of the product. If the product was actually manufactured by a third party, the petitioner could ask the third party to provide a technical drawing of the product with a collaborative statement that the product was manufactured based on the drawing. In such circumstances, the PRB might affirm the authenticity of the public use evidence if there is no counter evidence.

Utilising public use evidence in Chinese invalidation proceedings is difficult in practice, but it might be decisive for difficult cases where publication evidence is not readily available. In such circumstances, the petitioner has to be creative in preparing public use evidence in order to satisfy the requirements of the PRB as well as finding connections between collaborative evidence based on the commercial practice of the industry in order to increase the credibility of public use evidence. The PRB public use evidence requirements also demand manufacturers and vendors in the market to regulate their documents of sale during their daily business operations and to keep relevant records intact in order to defend their lawful rights and interests when under threat from a patent infringement lawsuit.

Jun Qiu



Mr Jun QIU is an attorney at law and patent attorney in China, and a partner at Liu Shen & Associates. Mr QIU specialises in patent litigation, invalidation and dispute resolution before SIPO and the courts, and advises on IP strategies and patent due diligence work. Mr QIU works in fields such as semiconductor processing, lithography, display technology, materials, medical apparatus and mechanical engineering. He also presents on various topics regarding Chinese patent litigation in international IP conferences. Mr QIU graduated from Tsinghua University with a bachelor’s degree and a master’s degree in engineering. He also studied and worked at the University of Michigan and graduated from John Marshall Law School with a Master of Laws degree.

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