Conflict and Harmonization of "Estoppel" in Patent Law

Author | Attorney Zhang Bowen, Intellectual Property Center

Under the binary system, based on different interpretation purposes and interpretation methods, the patentee is prone to inconsistent interpretation of the claims in the process of interpreting the claims. For example, in the examination stage of the patent, in order to obtain authorization and obtain a patent certificate, the patent applicant often hopes to constrict the interpretation of the claims to avoid conflicts between the protection scope of the patent and the prior art, so as to hope for quick authorization.

However, in patent infringement proceedings, since a stable and effective patent right has been obtained, the patentee may include the technical features that have been excluded at the examination stage into the protection scope of the patent right in order to seize the market. In order to ensure the consistency of the interpretation of the claims and the stability of the protection scope of the patent right, the protection scope of the patent from "birth to death" remains unchanged.

The current patent system has derived the principle of estoppel, which avoids the situation of secondary profit for the patentee.

(I) The concept of estoppel

In the field of contract law in common law countries, there is a principle called the "principle of estoppel of promise", which requires that the parties must not go back during the trial of the case, and must implement or abide by the promises made by the promisor in legal activities. This principle is implemented through a series of cases1.

At present, the principle of estoppel exists in various countries' patent systems, although the rules are different, but its origin is probably the principle of estoppel.

The relevant judicial interpretation of our country stipulates 2: The technical solution that the patent applicant or the patentee explicitly abandons the claim in the administrative stage, and the waiver has not been denied by the administrative organ, if the patentee in the patent infringement stage has clearly abandoned the technical solution into the scope of patent protection, hoping to expand the scope of patent protection, should not be supported by the people's court.

This clause is often referred to as the "estoppel principle". Since the estoppel principle spans the stage of patent authorization and patent infringement trial, it emphasizes the consistency of claim interpretation under the binary system. Therefore, in the process of studying the consistency of claim interpretation under the binary system, it will inevitably involve the study of the principle of estoppel.

(2) Understanding and application of the principle of estoppel

In the current patent theory, there are two understandings of the application of estoppel principle, namely the narrow estoppel principle and the broad estoppel principle. The narrow estoppel principle is the technical solution that the patent applicant or patentee expressly waives the claim in the administrative stage, and the waiver is not denied by the administrative organ. If the patentee includes the technical solution that has been clearly waived in the patent infringement stage into the scope of patent protection, hoping to expand the scope of patent protection, it should not be supported by the people's court.

In the narrow sense of estoppel principle, the author of the opinion is required to modify the claims or specifications by means of express exclusion before the principle of estoppel can be applied.

The broad estoppel principle is not limited to modifying claims or specifications by means of express exclusion, but also includes exclusion methods that can be derived by reasoning. The broad estoppel principle needs to be deeply understood in conjunction with the process of generating patent application documents, which are developed based on stimulating technological advancement3.

Existing patent documents include abstracts, abstract drawings, claims, specifications and accompanying drawings. The claims can be called the core content of the entire invention application text, which is a combination of law and technology; while the description is closer to the technology itself, focusing more on the implementation of the technical field where the invention is located and the rules of the invention technology itself.

If the principle of estoppel is placed in the generation process of the entire patent application document, according to the three modules of the patent application document, technical problems, technical solutions and technical effects. In the content of the technical problems solved, it is necessary to explain the existing technical difficulties to be overcome by the patent involved, and then it is necessary to list the technical background of the research and development of the patent involved.

For example, if a technical problem cannot be overcome by the prior art in the description of the background art, then the technical solutions of the prior art mentioned in the background art should be excluded and should not be included in the protection scope of the patent involved. Some local judicial interpretations 4 record: If the technical feature of the defendant is recorded in the background art, that is, the technical feature is a defective technical feature in the prior art, and the purpose of applying for a patent is to solve the defective technical feature, from the purpose of applying for a patent, the technical feature should not be included in the scope of patent protection.

The application of estoppel principle has been explored by all walks of life in recent years, and there are also some controversial issues, such as: in the application process of estoppel principle, what is the timing and prerequisite for activating the estoppel principle, and what is the "clear" in the "clear exclusion" in the principle of estoppel? 5.

(3) Problems existing in the application of the principle of estoppel

Some common problems in the application of the principle of estoppel in combination with judicial cases are discussed. In a case, the patentee applied to the State Patent Office for "a drug for the prevention and treatment of calcium defects and its preparation method" invention patent 6. The content of claim 1 of the patent application document is: "A drug for the prevention and treatment of calcium defects,...: 4-8 parts of soluble calcium,...".

In the patent examination stage, the examiner believes that "soluble calcium" can include various calcium agents, and its own meaning is too broad, which is a very high-level concept. If such a concept is written in the patent claims, the protection scope of the patent will undoubtedly be greatly expanded. However, the specification of the patent application document does not fully explain such a large range, but only selects "calcium gluconate" and "active calcium" for specification and demonstration, which are recorded in specific embodiments. Therefore, the writing method of the patent application document results in the claims not being supported by the specification, and the claims in the application document should be revised.

After receiving the review opinion, the applicant made amendments to the claims according to the requirements of the review opinion, the most critical of which was to accept the review opinion that "the claims are not supported by the description". In order to ensure the authorization of the patent document, the "soluble calcium" was specially modified to "active calcium", which is to modify a superior concept to a subordinate concept.

From the results of this modification, it seems that the applicant has explicitly excluded the technical feature of "calcium gluconate", and has explicitly excluded the technical feature of "calcium gluconate" from the scope of patent protection. The content of claim 1 of the post-patent authorization announcement text is: "A drug for preventing and treating calcium defects,...: 4-8 parts of active calcium,...

The patentee then commissioned a notary to collect evidence for the accused product, and then identified the ingredients of the accused product. The results of the identification were as follows: each milliliter contained 60 milligrams of calcium gluconate, 3 milligrams of zinc gluconate, and

10milligrams of lysine hydrochloride.

The first instance court and the second-instance court agreed that in the process of applying the principle of estoppel, only those technical features that are expressly excluded in order to make the patent application document innovative can be activated. If the technical features explicitly excluded are not based on making the patent document innovative, the principle of estoppel does not apply, that is, not all patent technical solutions that are expressly abandoned can be applied to the principle of estoppel.

In this case, the applicant's modification during the patent application process was not based on novelty, so such modification cannot be subject to estoppel.

The retrial court overturned the arguments of the first instance and the second-instance court, holding that under the current legal system, estoppel is not limited to the premise of novelty and inventiveness. In this case, the patent applicant abandoned the technical feature "calcium gluconate" during the patent examination process, regardless of the purpose of such modification, regardless of whether the technical feature was expressly excluded because of novelty and inventiveness.

According to the principle of estoppel, the patent text authorized and announced shall prevail. At this time, the scope of protection of the patent has clearly excluded the technical characteristics of "calcium gluconate". Since the alleged technical solution of the alleged infringing product is "calcium gluconate", and "calcium gluconate" belongs to the technical solution that the patent applicant has explicitly excluded.

Therefore, the alleged technical solution does not fall within the scope of protection of the patent in question.

In another Supreme People's Court case8, the judge held that the focus of this case was whether the "estoppel" principle applies to the patent owner's express exclusion statement. According to the provisions of relevant judicial interpretations 9, the "express denial" is regarded as an exception to the application of the "estoppel principle". When the judge explicitly rejects the statement of opinion, the express exclusion made by the applicant is invalid, and the express exclusion made by the applicant should not trigger the principle of estoppel.

In the patent grant stage of this case, the patent examination department rejected the express exclusion opinion stated by the patent applicant, and held a clear negative opinion. Later, there was no objection to this negative opinion in the oral examination stage of patent invalidation, so it can be said that the denial has been unanimously recognized by the State Intellectual Property Office.

Therefore, since the express exclusion statement made by the patent applicant is explicitly rejected at the examination stage and the oral examination stage of patent invalidation, in this case, it should be determined that the patent applicant's express exclusion opinion has been explicitly rejected, and the express exclusion opinion has expired, and the principle of estoppel should not be activated.

The invalidation of the patent applicant's express exclusion here does not conflict with the normal application of the "estoppel" principle. Therefore, the patent applicant's express exclusion opinion on feature A has no legal effect. According to relevant judicial interpretations, the "estoppel" principle should not be applied in this case.

During the trial process, the second-instance Court failed to grasp the methods of patent examination, patent invalidation oral examination, and overall observation of patent infringement judgment, and ignored the fact that in the patent examination stage, the statement of opinion made by the patent applicant has been "clearly rejected", and the clear denial has also been recognized by the patent invalidation oral examination stage. As a result, the determination of technical characteristics of the patent is not consistent and continuous, and the situation of "clear denial" in the patent examination stage cannot be deeply grasped. It is believed that there is no "clear denial" of the examination opinion to the right holder.

The second-instance Court's argument does not conform to the provisions of judicial interpretation, and draws the wrong conclusion that the principle of "estoppel" should be applied in the process of patent infringement judgment.

conclusion

From the above typical cases, it can be seen that the current judicial practice has the following conclusions about the principle of estoppel: if the parties explicitly exclude a certain technical feature in the administrative stage so that the application documents are patentable (including but not limited to overcoming the lack of novelty, unclear protection scope, and the claims are not supported by the specification), then in the patent infringement judgment stage, in the process of applying equivalent infringement, if the patentee attempts to include the technical features that have been explicitly excluded in its scope of protection, the principle of estoppel should be applied.

If the patent applicant only states the meaning of a technical feature in general at the administrative stage, but does not specify the waiver of a technical feature, the principle of estoppel shall not apply. If the party's statement of opinion expressly excluding a technical feature is "expressly rejected", the above-mentioned opinion expressly excluding a technical feature shall not apply estoppel principle.

1 Sun Li. A comparative study of the rule of estoppel and the principle of estoppel [J]. China Development, 2006 (02): 65-69.

Article 6 of the Interpretation of the Supreme People's Court on Several Issues Concerning the Application of Law in the Trial of Patent Infringement Disputes.

3. O'Illich Kauf, Translated by Clement: The Economics of the Patent System, Peking University Press, 2005, pp. 57-64.

4 Intellectual Property Division of Beijing Higher People's Court. Understanding and Application of the Guidelines for Patent Infringement Judgment (2017) of Beijing Higher People's Court [M]. Beijing: Intellectual Property Press, 2017:246-247.

5 Li Yunzhi. On the principle of estoppel and its application research [D]. Huazhong University of Science and Technology, 2006.

6-Kong Yanping. A medicine for preventing and treating calcium deficiency and its preparation method: China, invention patent. CN1060336C [P] .2008:2-14.

7 Supreme People's Court (2009) Mintizi No. 20 court verdict.

8 Supreme People's Court (2017) Supreme Court Minshen No. 1826 court verdict.

9 Article 13 of the Interpretation of the Supreme People's Court on Several Issues Concerning the Application of Law in the Trial of Patent Infringement Disputes (II).

Lawyer Profile

Zhang Bowen, lawyer

Attorney of

Deputy Director of the Patent Law Professional Committee of Zhiheng Intellectual Property Center

Patent Agent

Areas of expertise:

Focusing on patent business, including patent layout, patent invalidation oral examination, patent infringement litigation, patent search analysis, etc.

The case has been selected as one of the "Top Ten Typical Cases of Guangzhou Intellectual Property Court's 2022 Service and Protection of Scientific and Technological Innovation".

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