China: The Determination Of Obvious Mistakes In Patent Application Liang HONG v. Patent Reexamination Boardent Reexamination Board

Precise Rotating Compensator

HONG Liang v. Patent Reexamination Board -The Determination of Obvious Mistakes in Patent Application (Administrative Judgment (2011) Xing Ti Zi No.13 by the Supreme People's Court on May 11, 2012)

In patent invalidation procedure, if the technical solution defined by a claim fails to be clearly described in the detailed description, the claim would be invalidated because the claim fails to be supported by the description. In practice, particularly, with respect to patent application for utility model, which does not experience substantive examination, sometimes typing mistakes made when drafting claims is difficult be discovered and corrected. In some instances, although the patentee argues that these typing mistakes can be correctly understood by a person skilled in the art because they are obviously, the arguments usually would not be accepted by the Patent Reexamination Board without support of sufficient evidence. This eventually leads to invalidation of several valuable patents. The judge held in this case that, if, by looking into the nature and degree of the typing mistakes, the person skilled in the art can naturally identify the typing mistakes and appreciate the corrected meaning of the typing mistakes, the typing mistakes shall be interpreted in a corrected manner. Consequently, negative effect of the typing mistakes on validity of valuable patents can be reduced, especially in the current circumstance where there exists no post-grant correction procedure for correcting typos and other clerk errors.

The patentee, HONG Liang, owns a utility model patent No.ZL200720128801.1 titled "Precise Rotating Compensator." The patent relates to a rotating compensator, which absorbs the axial thrust and displacement through the relative rotation of an internal pipe and an external casing of the compensator. Claim 1 is reproduced as follows:

"A precise rotating compensator comprises an external casing, an internal pipe, a swaging flange, an extension pipe and a sealing material, wherein a flexible graphite packing is arranged between the internal pipe and the external casing; the butt of the packing is equipped with the swaging flange; the end of the swaging flange and a flange at an end of the external casing is connected by a bolt; a steel ball is positioned between an internal convex ring of the external casing and an external convex ring of the internal casing; the other end of the external casing is connected with the extension pipe, a clearance is left between the components; the characteristics is that, the extension pipe is a straight pipe, the internal diameter of which is the same as the internal diameter of the internal pipe, and they are in coaxial; the external side of the swaging flange is closely matched with the internal side of the external casing."(as illustrated below).

The Patent Reexamination Board (hereinafter, the "PRB") made a decision to invalid the patent upon a request filed before the PRB for invalidation of the patent. The PRB held that, the feature "the other end of the external casing is connected with the extension pipe, a clearance is left between the components" in claim 1 is inconsistent with the corresponding content described in the detailed description, i.e., "the straight extension pipe 5 is external to the external casing, ..., a clearance is left between the extension pipe 5 and the internal pipe 1." Because there exists no clearance between "the components" defined in claim 1 as "the components" were interpreted into the external casing and the extension pipe, which are firmly connected together, (actually, there exists a clearance left between the extension pipe 5 and the internal pipe 1), the technical solution of claim 1 cannot be obtained directly or generalized from the disclosure of detailed description. Claim 1 is thus invalidated for lack of support of the detailed description under Article 26.4 of the Chinese Patent Law (2001).

After reviewing the case, both the court of first instance and second instance affirmed the decision of the PRB. Both courts held that claim 1 fails to be supported by the detailed description because the technical solution defined in claim 1cannot be undoubtedly obtained from the disclosure of the detailed description. Additionally, the courts did not accept the patentee's argument that "the components" in claim 1 is a typo and can be correctly appreciated by the person skilled in the art.

The patentee initiated the retrial proceedings before the Supreme People's Court, arguing that "the components" defined in claim 1 is an obvious mistake that can be identified and correctly understood by the person skilled in the art after comprehending the detailed description.

The main question presented to the Supreme People's Court is that whether claim 1 fails to be supported by the detailed description because of the typing mistake in claim 1.

The judge held that, Article 26.4 of the Chinese Patent Law (2001) was enacted to ensure that the scope of protection of a claim should match the scope of disclosure of detailed description, wherein the protection scope shall not be broadened as exceeding the original disclosure of the detailed description, and shall not be narrowed as being limited to specific embodiments of the disclosed invention.

The judge pointed out that, in practice, the typing mistakes may be left in claims when drafting patent application documents. The typing mistakes can be classified into obvious mistakes and non-obvious mistakes based on the nature and degree of the mistakes. Regarding obvious mistakes, the person skilled in the art can identify these mistakes upon reading the claims, and understand relevant context and the whole description in a corrected manner correspondingly. Further, the person skilled in the art would not rigidly apply the identified obvious mistakes when practicing the technical solution defined in claim. As a result, where the person skilled in the art can understand correctly the intended meaning to be conveyed by the context of a claim in which there exists obvious typing mistake, it is improper to invalidate the whole claim under Article 26.4 of the Chinese Patent Law (2001), because this would result in imbalance between the protection conferred to the patentee and the contribution that the invention made over the prior arts.

The judge ascertained the following facts. In this case, the precise rotating compensator recited in claim 1 comprises an external casing, an internal pipe, a swaging flange, an extension pipe, and a sealing material, wherein an end of the external casing is connected to the internal pipe by the swaging flange, the other end is connected to the extension pipe. The rotating compensator absorbs the axial thrust and displacement through the relative rotation of the internal pipe and the external casing. It is impossible to connect the internal pipe to the external casing or connect the external casing to the extension pipe while leaving a clearance between them simultaneously. Therefore, "the components" in the feature "a clearance is left between the components" defined in claim 1 refer to the internal pipe and the extension pipe, instead of the external casing and the extension pipe. This interpretation complies with the detailed description, which recites, "the straight extension pipe 5 is external to the external casing 4 of which the inner diameter is the same to the internal pipe, a suitable clearance of 1-10mm is left between the extension pipe 5 and the internal pipe 1."

Finally, the Supreme People's Court reversed the court decisions of first and second instances, holding that claim 1 is valid under Article 26.4 of the Chinese Patent Law (2001), because the technical solution of claim 1 can be obtained from the disclosure of the detailed description.


Drafting patent application documents is challenging. Sometimes people may make errors when drafting application documents because of subjective reasons like immature drafting skills, and objective reasons like restriction of language itself for describing the technical feature. If the mistakes were discovered in examination procedure, they can be properly corrected. But, if the mistakes were left in the issued patent documents, they are quite harmful to the validity of the patent due to the limited manner under current Chinese legal framework for amending patent documents after granting of the patent right.

Other than China, many countries and regions provide sufficient remedies for correcting mistakes found in the granted patent documents, to balance between the protection granted to the patentee and the public's interest.

For example, in U.S., the patentee can amend the mistakes in claims caused by carelessness after the application has been granted through Reissue Procedure under 35 U.S.C. §251; in Europe, the patentee can amend the granted claims in narrowing manner through Limitation Procedure under EPC Art. 105b; in Japan, with respect to invention patent, the patentee can request an individual "Revised Review" Procedure before the JPO to amend the granted patent documents, with respect to utility model, the patentee can amend the registered utility model patent documents in a certain period after the technical search report has been made or the invalidation appeal has been requested, wherein the requirement of amendment for invention is identical to the requirement for utility model. The requirements both include narrowing the scope of claims, revising typos or mistranslation, interpreting ambiguous record.

In contrast, the granted Chinese patent documents can hardly be amended under current legal framework. Only the claims can be amended for both invention patent and utility model patent through invalidation procedure. Because the claims can only be amended in the manner of deletion of a claim, combination of claims and deletion of a technical solution, most of the mistakes cannot actually be amended through the invalidation procedure. In particular, because preliminary examination is applied to utility model in China, the patentee cannot amend the application documents in the preliminary examination period, making the amount of utility model patents having drafting mistakes substantively exceed the amount of invention patents. In the earlier examining procedure, besides the three manners of amendment in invalidation procedure, the PRB and the People's Court usually allow the patentee to interpret the meaning of obvious typos only, so almost all of the other mistakes cause the patent to be invalided or partial invalided due to ambiguity or being inconsistent with the description.

The outcome of the decision shows that, the patentee can clarify the meaning of certain drafting mistakes, expending the scope of the drafting mistakes which can be understood correctly. In this case, "the components" in the feature "a clearance is left between the components" recited in claim 1 literally refers to the external casing and the extension pipe. However, according to the mechanism of the external casing, the internal pipe and the extension pipe of the compensator and the corresponding content in the detailed description, "the components" refers to only the internal pipe and the extension pipe, rather than the external casing and the internal pipe or the external casing and the extension pipe. Obviously, the reason that the interpretation of "the components" cannot be understood as an obvious typo is based on logical analysis.

What type of drafting mistakes can be interpreted correctly? From the judge's viewpoint, the drafting mistakes can be classified into obvious mistakes and non-obvious mistakes according to their nature and degree. With respect to the obvious mistakes, a person skilled in the art will not improperly understand the literal meaning, but correct the meaning of the mistakes without damaging the public interest. In fact, it is necessary to correctly modify or interpret the obvious mistakes. Compared to the obvious mistakes, it is difficult to interpret the non-obvious mistakes in exclusive and certain manner, because no one knows what the mistakes should be. The amendment or interpretation of non-obvious mistakes should be limited strictly.

How can a person determine that a drafting mistake is obvious or not? A person may take into considerations the following two respects. First, the drafting mistake is obviously incorrect and inconsistent with the objective facts described in the detailed description. Second, a person skilled in the art can arrive only at the correct answer according to the general knowledge in the art, and the content of the patent documents on the basis of logical reasoning.

Although the outcome of the decision has a positive effect on the enforcement of patent right, especially utility model patent right in China, the applicant, especially foreign applicant should pay full attention to the drafting quality of utility model application documents. It is necessary to estimate the stability of the claims and correspondingly limit the scope of claims, and to avoid subjecting the challenge of validity due to the drafting mistake. On the other hand, the drafting mistakes are likely to present in the utility model patent documents filed by foreign applicants because of language translation, literal expression, etc. When dealing with mistakes which may affect the validity of patent, a person can try to find the correct meaning of the mistakes from the patent documents on the basis of logical analysis.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on

Click to Login as an existing user or Register so you can print this article.

Some comments from our readers…
“The articles are extremely timely and highly applicable”
“I often find critical information not available elsewhere”
“As in-house counsel, Mondaq’s service is of great value”

Mondaq Advice Centre (MACs)
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at and we will use commercially reasonable efforts to determine and correct the problem promptly.