Identifying common knowledge evidence for patent claims
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Identifying common knowledge evidence for patent claims


Quan Kang of DEQI assesses which evidence can be used to establish common knowledge when determining inventive step


The Guidelines for Patent Examination (hereinafter referred to as the examination guidelines) introduce the concept of "common knowledge" in determining the inventive step of a claimed invention. Specifically, when the distinguishing feature between the claimed invention and the closest prior art is common knowledge, it is usually thought a technical motivation exists in the prior art.

What is common knowledge? There is no clear definition of this concept in current Chinese laws and regulations, including the Patent Law and the Rules for the Implementation of the Patent Law. However, what can be regarded as common knowledge is stipulated in Guidelines for Patent Examination. The details are as follows:

Part II, Chapter IV, Section, "The said distinguishing feature is common knowledge, such as a customary means in the art to solve the re-determined technical problem, or a technical means disclosed in a textbook or reference book to solve the re-determined technical problem."

Part IV, Chapter II, Section 4.1, "During the collegiate examination, the panel may introduce common knowledge of the skilled art into the examination, or supplement the evidence by providing common knowledge such as those in a technical dictionary, a technical manual, or a textbook."

Part IV, Chapter VIII, Section 4.3.3, "(in the invalidation procedure), the party concerned may prove that certain technical means are common knowledge in the art with reference to the technical contents recorded in a reference book such as a textbook, a technical dictionary, or a technical manual."

According to the above provisions, during patent substantive examination, reexamination, invalidation, and litigation, there are generally three forms of common knowledge: 1. a textbook; 2. a technical dictionary; 3. a technical manual.

Two other forms of common knowledge evidence

In the invalidation and litigation procedures, could other forms of literature be cited to prove that a technical feature is common knowledge?

At present, two other forms of literature might be accepted by the Reexamination Board and the court as common knowledge evidences. A number of patent documents each disclosing the same technical feature(s), can be regarded as one piece of common knowledge evidence.

According to Article 13 of the "Administrative Litigation Cases for Patent Right Granting/Confirmation" in the New Development of Intellectual Property Trials of Beijing Higher People's Court (2016), a number of patent documents commonly known and accepted by those skilled in the art can be used to prove that a technical feature belongs to common knowledge.

The reason for such a form of common knowledge evidence is that more and more techniques are developing very rapidly and updating very fast. Thus many new techniques have already been widely used in the industry, and accepted and applied by technicians in this field. These have already become common knowledge, but are not written in textbooks, technical manuals and technical dictionaries. Considering such characteristics, Beijing Higher People's Court proposed that this kind of common knowledge evidence should consist of a number of patent documents disclosed before the filing date to be used together as one piece of evidence. In addition, in practice, such patent documents should preferably be owned by different applicants in order to corroborate the fact that the technique is already widely known by those skilled in the art.

National standards are documents that are formulated and approved through consultation between authoritative organisations in order to obtain the best order within a certain range and are used and reused in the art. These standards should be followed by those skilled in the art. In particular, national standards usually refer to relevant international standards, and are issued upon the approval of the competent authority through investigation, review, summary, adjustment and other work by many institutions at different phases. All regions in China adopt and comply with the standards when dealing with relevant technical issues. Therefore, national standards can be used alone as common knowledge evidence.

Example 1

Case No.: (2016) J. X. Z. Judgment No. 3766

Date of issue: December 6 2016

Application no. of the desired patent: CN200720109764.X

Filing date of the desired patent: May 25 2007

One of the distinguishing technical features is "a photoresistor is provided in the power supply circuit of the motor". The Reexamination Board provided four Chinese patents in the litigation procedure, each disclosing related contents about the photoresistor and the power supply circuit, to prove the above distinguishing technical feature belongs to common knowledge.

The judge held the opinion that common knowledge refers to what is known and grasped by those skilled in the art. Common knowledge is usually proved by means of textbooks, technical manuals and other forms of documents. If the technical facts had been disclosed by several professional journals, patent documents and other technical documents before the filing date of the patent application, they would also be regarded as common knowledge. Therefore, in the case that four patent documents each disclose the above distinguishing technical feature, it should be recognised as common knowledge. That is to say, the four patent documents could be used simultaneously to constitute a piece of common knowledge evidence.

Example 2

Case No.: (2015) J. Z. X. C. Z. Judgment No. 275

Date of issue: August 18 2015

Application no. of the desired patent: CN200920075414.5

Filing date of the desired patent: July 28 2009

The additional feature in claim 2 is "a thread angle of the screw body is 65 degrees", which was claimed as common knowledge by the third party (the petitioner for invalidation) with Evidence 6th.

Evidence 6th is a national standard GB/T5280-2002 for self-tapping screw thread. Its publication date is December 5 2002, earlier than the filing date of the desired patent. It is recorded in this evidence that the thread angle in sheet metal is 60 degrees.

The judge held the opinion that Evidence 6th is a national standard already implemented in the field before the filing date of the desired patent. Although the angle in claim 2 differed by five degrees from that in Evidence 6th, no evidence showed that there is an unexpected technical effect brought about by these five degrees. Therefore, the additional technical feature of claim 2 belongs to common knowledge. That is to say, the court considered that national standards could be used as common knowledge evidence.

Example 3

Case No.: (2015) J. Z. X. C. Z. Judgment No. 3495

Date of issue: July 19 2016

Application no. of the desired patent application: CN200810132469.5

Filing date of the desired patent application: July 11 2008

There are two distinguishing technical features between the between the patent application and the closest prior art. The applicant deems that since the two distinguishing technical features are not recorded in any 3GPP protocol document, they do not belong to common knowledge.

The judge held the opinion that 3GPP protocol does not meet the requirement of common knowledge evidence in the sense of Chinese Patent Law, and not all common knowledge in the telecommunication field shall be recorded in the 3GPP protocol, thus the applicant's claim on this lacks factual basis and cannot be supported.

Can 3GPP protocols be used as common knowledge evidence?

3GPP protocol is one of the most frequently used technical standards. Can it be used as common knowledge evidence?

Beijing Intellectual Property Court holds the opinion that the scope of common knowledge is obviously smaller than that of the prior art. A certain prior art can be recognised as common knowledge only when its technological development level in the field prior to the filing date (or priority date) has been already widely accepted and applied by those skilled in the art, and the prior art has reached the level of well known to the public in this field. Therefore, a prudent attitude and an objective and fair criteria should be applied to determine common knowledge.

Specifically, 3GPP is a major organisation in the field of global wireless communication. It focuses on formulating technical specifications and technical reports instead of technical standards, with the purpose of ensuring the interchangeability, compatibility, and versatility of telecommunication products or services. However, according to the above judgment, not all prior art is common knowledge, thus 3GPP standard documents are not definitely common knowledge. Whether or not the technical scheme recorded in the 3GPP protocol is common knowledge will depend on the specific circumstances including the technology per se, its useable range, and so on. Therefore, 3GPP standard documents alone cannot prove that the recorded technologies are of course common knowledge in this field. Instead, such 3GPP protocol documents will be combined with other documentary evidence to prove whether or not the technical feature is well known to the public.

Generally, common knowledge evidence includes:

  • common knowledge evidence that could be used alone: textbooks, technical manuals, technical dictionaries, and national standards;

  • common knowledge that shall be used together: multiple patent documents, 3GPP protocol (used with other documentary evidence).

Kang Quan



Kang Quan is a patent attorney at DEQI IP Law Corporation and has practised IP law for 15 years. She represents clients in the IP court. She earned a BSc degree in mechanical engineering and automatisation and an MSc degree in mechanism and automation engineering from Beijing Institute of Technology.

She focuses on drafting and prosecuting patent applications, re-examinations, and invalidations. She was named a Beijing Outstanding Patent Attorney in 2015, and was elected as a teacher at Capital Patent Agency Teacher Library. She is a member of the All-China Patent Agents Association.

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