Author：Xiaobin ZONG

Beijing Jerrat Springs Damper Technology Research Center v. Beijing JZTH Buffer Technology Co., Ltd. et al. (Civil Ruling (2013) Min Shen Zi No. 1146 by the Supreme People’s Court on November 18, 2013)

In determining whether a patent infringement is established based on the doctrine of equivalents (“DOE”), attention should be paid to which feature in a claim is compared against which feature of an accused infringing product. Only those features of a product that are not identical to their counterparts in the claim should be taken into consideration for the purpose of DOE. Determination under DOE is different from the determination on inventiveness during patent prosecution – the requirement of “three substantially, one ordinarily” should be met.

The patentee in this case has a utility model patent entitled “fast-advancing and slow-returning damper of viscoelastic fluid type,” which was filed on December 28, 2001 and issued on December 18, 2002. Independent claim 1 of the patent reads: “a fast-advancing and slow-returning damper of viscoelastic fluid type, mainly comprised of an outer housing (1), an inner housing (2), a piston (3), a viscoelastic fluid (4) and a sealing member (5), characterized in: the viscoelastic fluid (4) being filled in an inner chamber (22) of the inner housing (2), the piston (3) and a piston pole (31) being coupled and put into the inner chamber (22) of the inner housing (2), a cover (21) being coupled to the inner housing (2) to form an integral body, one-way limiting devices (32) being circumferentially provided on the piston (3), the one-way limiting devices (32) being opened during a compression phase and closed during a returning phase, and a clearance being provided between the piston (3) and the inner chamber (22).” The patentee filed a lawsuit on September 11, 2009 alleging that one of the defendants[1] made and sold a product that infringed the patent right.

The accused infringing product is a damper device that appears to have a similar structure. As a primary difference from claim 1, the accused infringing product has one-way valves provided circumferentially on the piston which, however, are configured in an opposite manner – the valves are closed during the compression phase while opened during the returning phase. Both the first instance and second instance courts decided that the product did not infringe the patentee’s right. The patentee then filed a request for retrial before the Supreme People’s Court alleging that the manner of providing the one-way valves in the product is equivalent, though not identical, to the manner of providing the one-way limiting devices in claim 1, because both manners of configuration for the one-way valves would be easily conceivable for a person ordinarily skilled in the art.

It is found through the retrial that the description of the patent explains: “an object of the utility model is to provide a fast-advancing and slow-returning damper of viscoelastic fluid type, which can rapidly damp, when an impact loading is applied, to absorb most of the impact energies for protection of the apparatus, and which then slowly and stably returns to relieve snapback for protection of the apparatus and for a lowered noise,” “the utility model utilizes the following technical solution to achieve the above object: … one-way limiting devices (32) are circumferentially provided on the piston (3), the one-way limiting devices (32) being opened during a compression phase and closed during a returning phase,” “owing to the technical solution above, the utility model has the following advantages and effects: … 2. the utility mode can withstand a large impact loading: the inner housing advances fast while returns slowly, returning is achieved automatically after the external loading is released without the need to provide a returning mechanism, the apparatus is effectively protected and noise is lowered.”

The Supreme People’s Court holds: “according to the record in the description of the patent, the object of the patent at issue is to provide a fast-advancing and slow-returning damper of viscoelastic fluid type. In order to achieve this object, the patent at issue applies such a manner of configuration on the one-way limiting devices that they are opened during the compression phase and closed during the returning phase in order to achieve the effect that the inner housing will advance fast but return slowly. In this regard, claim 1 of the patent at issue provides an express limitation on the manner of configuration of the one-way limiting devices. The accused infringing product applies however a manner of configuration on the one-way limiting devices that are closed during the compression phase and opened during the returning phase, and achieves an effect that the inner housing will advance slowly but return fast. Therefore, the manner of configuration of the one-way limiting devices in the accused infringing product is neither identical nor equivalent to the manner of configuration defined in claim 1 of the patent at issue.” Accordingly, the Supreme People’s Court rejects the request for a retrial.

Fig. 1 of the patent at issue

Interpretation and Analysis

If an accused infringing action (product or method) includes all the technical features stated in a claim, then it is determined to fall within the extent of the claim. Based on the aforesaid, nevertheless, the DOE can extend, to some degree, the degree of protection expressly described in a claim[2]. Article 17 of the Several Provisions of the Supreme People’s Court on Issues Relating to Application of Law to Adjudication of Cases of Patent Disputes (Judicial Interpretation [2001] No. 21)[3] provides that, “the first paragraph ‘the extent of protection of the right for invention or utility model shall be determined by the terms of the claims. Article 56 of the Chinese Patent Law provides that the appended drawings may be used to interpret the claims’ of means that the extent of protection of the patent right should be determined by the necessary technical features expressly stated in the claims, including the extent as determined by the features equivalent to the necessary technical features. The equivalent features refer to the features which use substantially the same means, perform substantially the same function, and produce substantially the same effect as the stated technical features, which can be contemplated by a person ordinarily skilled in the art without inventive labor.” Therefore, even if an accused infringing product or method does not include some technical features in a claim (i.e. no “literal infringement” is established), the product or method is still regarded as falling within the extent of protection of the claim provided that it includes a feature equivalent to that technical feature.

Acting as one of the attorneys represented the defendant in this case, the author would like to point out the following two points in determination of a patent infringement under the DOE.

First, must ascertain as to which feature in a claim is compared against which feature of an accused infringing product. Only those features of the product that are not identical to its counterparts in the claim should be taken into consideration for the purpose of the DOE. It should be especially avoided to compare the accused infringing technical solution as a whole with the whole technical solution of the claim. For this case, the patentee alleged that both the patent and the accused infringing product use the means of providing one-way valves, perform the function of speed adjustment of the viscoelastic fluid, and produce the effect of absorption of the impact energies, and its interchanging are obvious to a person ordinarily skilled in the art. In fact, however, the feature of the accused infringing product that is different from the corresponding technical feature in the claim is not the “one-way valves,” but their manner of configuration. The alleged function of “speed adjustment” is introduced by the “one-way passing” property of the valves themselves, and the alleged effect of “absorption of the impact energies” is achieved by the property of material from the viscoelastic fluid. In other words, such function and effect are not brought by the exact feature to be compared, i.e. by the manner of configuration of the one-way valves. In determining whether equivalent infringement is established, comparison should be made between the technical feature of “the one-way limiting devices being opened during a compression phase and closed during a returning phase” stated in the claim and the corresponding feature of “the one-way valves being closed during a compression phase and opened during a returning phase” in the accused infringing product, same as what the Supreme People’s Court has done.

Second, determination under the DOE is different from the determination on inventiveness during patent prosecution – the requirement of the “three substantially, one ordinarily” should be met. For this case, if merely the manner of configuration of the one-way limiting devices is considered, a person ordinarily skilled in the art might be able to conceive of the manner of configuration in the accused infringing product when this person is aware of the manner of configuration in the patent at issue, without an inventive labor – if one-way valves are to be provided circumferentially on the piston, the two manners of configurations would be the only available options. After the publication of the patent at issue, if an invention patent application were filed directed to the technical solution of the accused infringing product, it could be questioned whether the application is inventive. However, as to determination on infringement, the functions performed and the effects produced are not “substantially the same” at all for the two manners of configurations of the one-way valves – the manner of configuration of the one-way limiting devices in the patent at issue performs the function of allowing a wider flow path of the viscoelastic fluid in the compression phase than in the returning phase, and produces the effect of fast-advancing and slow-returning of the inner housing, while the manner of configuration of the one-way valves in the accused infringing product performs the function of allowing a wider flow path of the viscoelastic fluid in the returning phase than in the compression phase, and produces the effect of slow-advancing and fast-returning of the inner housing. Therefore the corresponding feature in the accused infringing product is not an “equivalent feature” under the judicial interpretation above. Likewise, in another invention patent infringement lawsuit[4] the Supreme People’s Court found that the accused infringing method included steps No. 6, 7, 8 and 10 which perform the same actions as steps No. 7, 6, 11 and 10 of the claimed method respectively; the Supreme People’s Court decided that steps No. 6 and 7 in the accused infringing method were equivalent to steps No. 7 and 6 in the claimed method, while steps No. 8 and 10 in the accused infringing method were not equivalent to steps No. 11 and 10 in the claimed method – the underlying reason is that interchanging steps No. 10 and 11 produces a technical effect that is substantially different, whereas interchanging steps No. 6 and 7 does not.

With the above two points in mind, one should be able to reasonably draw a conclusion for this case that no infringement under the DOE is established.

The Opinions of the Supreme People’s Court on Issues concerning Maximizing the Role of Intellectual Property Right Trials in Boosting the Great Development and Great Prosperity of Socialist Culture and Promoting the Independent and Coordinated Development of Economy requires that “having substantially the same means, function and effect, and being obvious to a person ordinarily skilled in the art should be the prerequisite to an infringement under the DOE; this should be avoided to apply to an infringement under the DOE in a simple and mechanical manner or to inappropriately extend its applicability.” The ruling of the Supreme People’s Court on the case discussed fully reflects these prerequisites, and the case is listed by the Supreme People’s Court as one of the 2013 Top 50 typical intellectual property cases in China courts.

Moreover, it is expressly provided in the Guidelines for Patent Infringement Determination[5] issued by the Beijing High People’s Court in 2013 that the application of the DOE is restrained, for example, by the dedication rule, rule of estoppels, etc. In practice, Jiangsu High People’s Court held in Hunan Corun New Energy Co., Ltd. v. Alantum Advanced Technology Materials (Dalian) Co., Ltd.^[6] that for a numerical range with clear endpoints in a claim, application of the DOE should be strictly controlled, especially in case where a technical feature is significantly different from the range defined in the claim. It can be understand that the courts may begin assuming a prudent attitude to situations where the DOE should be applied. If a patent infringement is to be established under the DOE, one should make careful technical analysis according to the requirement of the “three substantially, one ordinarily.”

[1] This case actually involves co-defendants. Another defendant is not related to the subject of this article and his actions will not be discussed.

[2] Xintian Yin, Introduction to the Patent Law of the People’s Republic of China, 598 Intellectual Property Publishing House Co., Ltd. 2011.

[3] Article 17 of the Several Provisions of the Supreme People’s Court on Issues Relating to Application of Law to Adjudication of Cases of Patent Disputes (Judicial Interpretation [2005] No. 4) has been amended to “the first paragraph ‘the extent of protection of the right for invention or utility model shall be determined by the terms of the claims. The description and the appended drawings may be used to interpret the terms of the claims’ of Article 59 of the Patent Law means that the extent of protection of patent right should be determined by all the technical features stated in the claims, including the extent as determined by the features equivalent to the technical features. The equivalent features refer to the features which use substantially the same means, perform substantially the same function and produce substantially the same effect as the stated technical features and which can be contemplated by a person of ordinary skill in the art at the time of occurrence of the accused infringing action without inventive labor.”

[4] Chen Shundi v. Zhejiang Lesheros Household Articles Co., Ltd. et al., Civil Judgment (2013) Min Ti Zi No. 225 by the Supreme People’s Court

[5] Cf. Articles 56 and 57.

[6] Civil Judgment (2011) Su Zhi Min Zai Zhong No. 0001 by Jiangsu High People’s Court