Claim Construction of Means-plus-function Claim, Based on the Judgments of the Taiwan Intellectual Property Court

07 September 2015

Claim Construction of Means-plus-function Claim, Based on the Judgments of the Taiwan Intellectual Property Court

Claim construction is always an important issue either for an invalidation action or an infringement assessment. In particular, the issue would be more complicated and disputable when the claim is written in means-plus-function or step-plus-function language.

The Taiwan Patent Act allows patent applicants to draft their claims in means-plus-function or step-plusfunction language. According to Rule 19 of the Enforcement Rules of the Patent Act, when constructing a means-plusfunction or step-plus-function claim, “… [s]uch claim shall be interpreted to cover the corresponding structure, material, or acts described in the description and equivalents thereof.”

Means-plus-function or step-plusfunction language may help patent applicants to define their inventions in a concise manner since such language merely describes the functions of the means or step while covering all of the possible examples for practicing the function. However, many issues including definiteness, support by description, whether the technical feature fulfills the definition of meansplus- function or step-plus-function language, the claim construction of means-plus-function or step-plusfunction language, etc., may arise during either patent prosecution or patent litigation against possible infringing production.

Oerlikon Heberlein Temco Wattwill Inc. (Oerlikon) filed a civil action against Dong Hong Textile Co., Ltd. (Dong Hong) claiming Dong Hong infringed Oerlikon’s Taiwan Patent No. I260354, which includes the claims written in means-plus-function language. The case is considered a representative case for constructing the scope of the claim written in means-plus-function language in Taiwan.

The patent at issue is related to a device for the air treatment of yarn in a yarn canal. The inventive concept of the device is using a “release-aid means” to release the spring pressure applied to the lever holding an insert (such as an air jet nozzle for interlacing, gyrating and winding yarn) during the operation of the apparatus treating yarn. Claim 1 of the patent at issue comprises the technical feature “release-aid means” in means-plus-function language. Two embodiments are disclosed in the specification of the patent at issue. The case went through two instances in the IP Court; in both instances, claim construction of the “release-aid means” was thoroughly discussed. To decide whether the possibly infringing product falls into the scope of the claims of the patent at issue, the IP Court first confirmed which of the embodiments is infringed by the product, and then constructed the claims of the patent at issue.

In the first instance, the IP Court considered that the possible infringing product did not literally infringe the patent at issue; however, infringement under the doctrine of equivalence was found. In the second instance, the IP Court held that the product literally infringes the patent at issue. The interpretations of the means-plus-function features are also different in the two instances. Only the first embodiment was included in the claim construction in the first instance; while in the second instance, the claim was constructed based on both of the embodiments described in the specification of the patent at issue. Moreover, in the second instance, the IP Court further indicated that the scope of the “release-aid means” shall include the equivalent scope derivable beyond any doubt by a person having ordinary skill in the art.

During the second instance, the plaintiff argued that the description “a pivotal axis (20) mounted to the upper carrier (31), and a sliding lever (21) is maintained on the pivotal axis (20)”, which was read into the “release-aid means” in the first instance, should not be included in the claim scope since the description does not carry out the specific function. That is to say, such limitation does not have any link or association with the function. The IP Court agreed with the plaintiff at this point and removed the description from the scope of the “release-aid means”.

Based on the foregoing judgment rendered in the second instance, one may conclude that the claim construction of the technical feature written in means-plus-function or stepplus- function language shall be made based on the following:

 

(1) The claim construction shall be based on all of the embodiments or working examples described in the specification of the patent at issue.

 

(2) The limitations read into the construction should be clearly linked to or associated with the function described in the technical feature.

 

(3) The scope of the technical feature shall include the equivalent scope derivable by a person having ordinary skill in the art without any doubts.

 

In the foregoing case, the Taiwan Intellectual Property Office (TIPO) did not present any opinions as to the claim construction of the technical feature written in means-plus-function language either during patent prosecution or the examination of the invalidation action. More cases would be needed to determine the extent of influence of TIPO’s examination opinions on the IP Court’s claim construction.

Due to the complicated nature of constructing a means-plus-function or step-plus-function claim, special care should be put on the links or associations of the embodiment and the specific function when drafting patent application. Furthermore, the description should disclose the embodiments for the means-plusfunction or at least as many as possible so as to obtain the most extensive scope of protection.


About the author

 Harriet Chen

Harriet Chen

Harriet Chen is a patent attorney at Tai E International Patent & Law Office in Taiwan. She counsels clients on intellectual property issues, including patent prosecution and patent strategy in mechanical engineering and design patents.

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