Claim construction in patent infringement litigation
Claim construction to determine the scope of protection of a patent claim is a critical element of patent infringement litigation. The Patent Law sets out the basic principles of claim construction: the scope of protection shall be determined by the claims, and the content of the claims can be interpreted with reference to the specification and the appended drawings.
The Explanations of Several Issues in Application of Laws Relating to Trial of Patent Infringement Disputes, issued by the Supreme People’s Court, provide guidance on the application of these basic principles. A guiding decision of the Supreme People’s Court provides further assistance in cases where claim construction based on the basic principles and the explanations is unsuccessful.
Generally, claim construction shall be done by a person with ordinary skill in the art based on the content of the claims, with consideration of the specification and the appended drawings, relevant claim(s), patent prosecution history, tool books, textbooks and common knowledge in the art.
Intrinsic and extrinsic evidence
The claim sought to be construed, the specification, the appended drawings, the relevant claim(s) and the patent prosecution history files serve as intrinsic evidence for claim construction. Tool books, textbooks and the common knowledge in the art serve as extrinsic evidence for claim construction. Generally, intrinsic evidence has a higher priority than extrinsic evidence. In practice, the courts will consider the intrinsic evidence first, followed by the extrinsic evidence if the scope of protection of the claim cannot be determined based on the intrinsic evidence.
The prosecution history – an important part of the intrinsic evidence – may comprise detailed explanations and/or further limitations for the technical features or the technical solution in the claim to be construed. In particular, the rights holder may allege what should be covered by the claim or what should be excluded from the claim in the prosecution history. Therefore, the prosecution history may serve as a correction to the scope of protection of the claim and usually has a higher priority than other intrinsic evidence. The more recent the prosecution history file, the greater weight it is given.
In 2015 the Shanghai Higher People’s Court issued its final decision in Haldex v Wuhan Yuanfeng. Plaintiff Haldex sued Wuhan Yuanfeng for infringement of its patent relating to a disc brake before the Shanghai Second Intermediate People’s Court. Claim 1 of the patent defined a feature of “the respective push bolts (39) act on a propulsion place (38), such that the caliper (16) separates a cross bar (36) and the propulsion plate (38) by closing a lid (7) of a cavity of the caliper (16)”. In interpreting the feature of “a lid (7) of a cavity of the caliper (16)”, the court referred to a response made by Haldex during the substantive examination proceeding before the State Intellectual Property Office. In its response, Haldex had stated that the lid was located on the brake disc side of the caliper; otherwise, the push bolts would not act on the propulsion plate and thus the caliper would not separate the cross bar and the propulsion plate by closing the lid of the cavity of the caliper. Based on this response, the Shanghai Second Intermediate People’s Court interpreted the term ‘lid (7)’ in the claim to be the same as “a lid which is used to close a cavity of a caliper, and is used to separate a cross bar and a propulsion plate” in the allegedly infringing product, and in turn held that the product fell within the scope of protection of claim 1. Wuhan Yuanfeng appealed to the Shanghai Higher People’s Court, which rejected the appeal on April 22 2015.
The Shanghai Higher People’s Court referred to Haldex’s response during prosecution of the patent to interpret the location and function of the lid so as to determine the protection scope of the claim, and finally decided in favour of Haldex. This departs from the prevailing trend in cases in which prosecution history is considered for claim construction: it is usually used as evidence to oppose the rights holder under the doctrine of prosecution history estoppel.
Interpretation of functional features
The interpretation of functional features is an important part of claim construction and has drawn considerable attention. A ‘functional feature’ usually refers to a feature that is defined by functions or effects, rather than a specific structure. According to the explanations of the Supreme People’s Court, a functional feature of the claim should be interpreted to cover only the specific implementations of the functional feature described in the specification and the appended drawings, as well as equivalents thereof – that is, features which can achieve substantially the same function and have substantially the same effect by substantially the same measure. In other words, the term ‘functional feature’ does not cover implementations that differ from those described in the specification, even if they can realise the same function defined by the functional feature.
In 2015 the Shanghai Higher People’s Court issued its final decision in Xuliangjie v Shanghai Xiangkui. Plaintiff Xuliangjie sued Shanghai Xiangkui before the Shanghai Intellectual Property Court for infringing his patent relating to a push-and-pull automatic shoe cover machine. Claim 1 of the involved patent defined a feature of “a first stop block (8) and a second stop block (9) arranged respectively at a front end and a back end of a hole (2) for inserting a foot”. The Shanghai Intellectual Property Court held that the features of “a first stop block (8)” and “a second stop block (9)” were functional features, and interpreted the first stop block (8) and the second stop block (9) as hinged components with a pendulum structure or elastic blocking strips according to the specification and the appended drawings. In contrast, the allegedly infringing product had a rectangular block arranged at the front end of the hole for inserting a foot and a slideway with an arc at the back end of the hole. Therefore, the Shanghai Intellectual Property Court held that the allegedly infringing product achieved the blocking function through a technical measure that apparently differed from the second stop block (9) in claim 1, although the slideway with the arc at the back end of the hole in the allegedly infringing product had a blocking effect to some extent. The plaintiff appealed to the Shanghai Higher People’s Court, which rejected his appeal on December 15 2015.
The Shanghai Higher People’s Court stated that the arc portion of the slideway in the allegedly infringing product could generate a frictional force due to its contact with a buckle, and the shoe cover was open when the frictional force and a strengthening force of an elastic band were in balance, such that the frictional force could have a similar blocking effect. However, this technical measure was totally different from the technical solution of the “second stop block” in claim 1.
If only the literal meaning of the functional feature “second stop block (9)” were considered, the arc at the back end of the hole in the allegedly infringing product would be covered by the feature “second stop block (9)”, since it also had a blocking or stop effect. However, based on the principles on interpreting functional features as set out in the explanations of the Supreme People’s Court, the functional feature “second stop block (9)” was limited by its specific implementations described in the specification.
Non-infringement due to unsuccessful claim construction
Successful claim construction is a precondition for a determination of infringement. However, in practice, claim construction based on intrinsic evidence and extrinsic evidence under the above principles is not always successful. In such circumstances, a feature comparison between the patent and the allegedly infringing product is impossible. The court hearing the infringement case will generally suspend the proceedings until the Patent Re-examination Board has issued a patent invalidation decision on the clarity of the scope of protection of the involved claim, but will not issue a non-infringement decision directly due to the lack of clarity of the claim. However, this procedure is very inefficient.
In 2015 the Supreme People’s Court issued a guiding decision in Wanqing Bo v Shanghai Tianxiang, confirming that a non-infringement decision may be made directly without a feature comparison if the claim construction still fails based on all available evidence, under the above principles for claim construction.
Plaintiff Wanqing Bo sued Shanghai Tianxiang for infringing his patent relating to an anti-electromagnetic radiation coat before the Chengdu First Intermediate People’s Court. Claim 1 of the involved patent defined a feature of “high magnetic permeability”. However, the meaning of the term ‘high’ here was neither defined in the claim nor described in the specification, and could not be determined by those skilled in the art based on the common knowledge in the art. Therefore, the Chengdu First Intermediate People’s Court alleged that it could not be determined that Shanghai Tainxiang’s product infringed the claim, since the exact value range of the high magnetic permeability could not be determined. It thus issued a non-infringement decision in favour of Shanghai Tainxiang. Bo appealed to the Sichuan Higher People’s Court, which upheld the decision of the Chengdu First Intermediate People’s Court. Bo further appealed to the Supreme People’s Court, which rejected his appeal on December 28 2012.
The Supreme People’s Court has had a major influence on the issue of unclear claims in infringement cases, even before it issued its guiding decision in Bo Wanqing v Shanghai Tianxiang. Another influential case – Nokia v Huaqin, which came before the Shanghai First Intermediate People’s Court and the Shanghai Higher People’s Court from 2011 to 2014 –further reflects the above principle. Nokia v Huaqin also involved claim construction concerning a functional feature.
In Nokia v Huaqin, Nokia sued Huaqin for infringing its patent relating to a terminal device before the Shanghai First Intermediate People’s Court. Claim 7 of the involved patent stated that “the terminal device is configured to selectively apply the data transfer method in a message editor used for entering messages”. The Shanghai First Intermediate People’s Court held that this feature was a functional feature and the scope of protection of claim 7 could not be determined, since no particular implementation was given in the specification and drawings. It thus held that the allegedly infringing product did not infringe claim 7. Nokia appealed to the Shanghai Higher People’s Court, which rejected its appeal on February 24 2014.
The Shanghai Higher People’s Court pointed out that a ‘functional feature’ is a feature defined by its function or effect, except that the technical content of the feature can be directly and clearly determined by those skilled in the art based on the claims, specification and drawings. The court interpreted the above feature in claim 7 as a functional feature based on the above definition. It held that the scope of protection of the claim could not be determined, since the above feature had no particular implementations described in the specification; thus, the allegedly infringing product did not infringe claim 7.
In practice, the Chinese courts abide by the basic principle of claim construction and the explanations of the Supreme People’s Court, such that the scope of protection of a patent is appropriately determined with reference to intrinsic evidence such as the patent document and prosecution history and extrinsic evidence such as textbooks and tool books. A feature comparison between the relevant claim and the allegedly infringing product will be conducted on the basis of successful claim construction. On the other hand, a non-infringement judgment will be directly issued on the basis of unsuccessful claim construction.
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Juan Wang, a senior associate at Liu, Shen & Associates, qualified as a patent attorney in 2007 and as an attorney at law in 2008. Her practice includes patent prosecution, patent invalidation, patent infringement analysis and litigation, and client counselling with a particular focus on image processing, communication and electronics.
Dr Wang received a bachelor’s degree from Northern Jiaotong University in 1999, a PhD in electronic engineering from the Chinese Academy of Sciences in 2004 and an LLM in intellectual property from the John Marshall Law School, Chicago, United States in 2014.
Jinlin Chen, a senior associate at Liu, Shen & Associates, qualified as an attorney at law in 2009 and as a patent attorney in 2011. His practice includes patent prosecution, patent invalidation, patent infringement analysis and litigation, and client counselling in optics and electronics. Dr Chen also lectures on Chinese patent law to clients and new associates.
Dr Chen received a bachelor’s degree in optoelectronics in 2004 and a PhD in optical engineering in 2009 from Huazhong University of Science and Technology, and an LLM in civil and commercial law in 2014 from the China University of Political Science and Law.