The Enforcement Rules of the Patent Act permit a combination of multiple technical features of an invention to be defined in “means-plus-function” or “step-plus-function” language. In general, “means-plus-function” language shall be construed to cover “the structure, material or acts corresponding to the function” described in the specification and the equivalents thereof.
While it is worthwhile to have a close look at how the above-noted rules are applied to actual cases, the IP Court has recently expressed its opinion regarding the construction of means-plus-function claims. This precedent case is summarized as follows:
Two invalidation actions against a patent were filed with the Taiwan Intellectual Property Office (hereinafter referred as the TIPO) in a row. In the first invalidation action, after the Petitioner filed an appeal with the Board of Appeals and, in turn, an administrative litigation with the IP Court against the Decision rendered by the TIPO deeming the patent at issue to be valid, the IP Court concurred with the TIPO and expressed in its Judgment that:
The element, “immediate stop unit”, recited in the claims of the patent, is defined by the function of “generating a control signal to make two ends of the magnetic poles of the stator have the same electric potential so as to immediately stop the fan system” without a structure to perform the function recited in the means-plus-function limitation. Therefore, it is kind of a means-plus-function language and needs to be construed based on the circuit of the unit as disclosed in the one and only embodiment of the specification. As the references cited by the Petitioner to establish reasons for invalidity of the patent did not disclose an “immediate stop unit” capable of “making two ends of the magnetic poles of the stator have the same electric potential,” recited in the claims of the patent, the patent apparently has an inventive step and is valid.
A second invalidation action was then filed with the TIPO by another party. While the Patentee amended the claims during the invalidation proceedings, the definition for the “immediate stop unit” was left unchanged. Therefore, the TIPO took a stance similar to the IP Court in its Judgment rendered in the first invalidation action, i.e. the “immediate stop unit”, a means-plus-function language, needs to be construed based on the circuit of the unit described in the one and only embodiment of the specification, including two switches, an energy storage and a resistor, where the energy storage and the resistor are electrically connected “in parallel”. Since the cited references disclosed an energy storage and resistor in “series connection” rather than in “parallel connection,” the TIPO found the patent to be valid.
The Petitioner was dissatisfied with the TIPO’s decision and filed an appeal with the Board of Appeals and subsequently an administrative litigation with the IP Court. Prior to the oral proceedings, the Patentee amended the claims, this time, changing “the immediate stop unit” to include “two switches, an energy storage and a resistor, wherein the energy storage and the resistor are electrically connected,” a move that incorporated into the claims the elements disclosed in the embodiment of the specification. The IP Court agreed to review the case based on the amended claims.
The main issue that ought to be addressed then was whether the claims of the patent, as a result of the post-grant amendment, are still the so-called “plus-means-function” claims. In other words, consideration should be given to whether the energy storage and resistor that are electrically connected can be interpreted as being equivalent to “the energy storage and the resistor are electrically connected in parallel”.
The IP Court expressed that means-plus-function language ought to be interpreted to cover the structure, material or acts described in the specification and equivalents thereof that can perform the function recited in the means-plus-function limitation. Given that the granted invention does need two switches and an energy storage to function, including a resistor in the circuit that does not perform the function recited in the means-plus-function limitation, and that a resistor allows an energy storage to rapidly discharge electricity, the manner in which the TIPO interpreted the claims of the patent was improper.
Further, the IP Court opined that the amended claims, in which the complete structure of the immediate stop unit is recited, no longer falls under “means-plus-function” language. Thus, the scope of the amended claims needs to be construed based on the literal wording of the claims, rather than the structure described in the embodiment of the specification. In view of this finding, the IP court held that the patent is invalid for lack of inventive step. The Supreme Administrative Court affirmed the judgment of the IP court.
It can be learnt from this case that, when drafting a means-plus-function claim, a practitioner should give elaborate care to the function of each separate element and avoid incorporating into the claims all the elements of an invention without heeding function. The rationale underlying this is that, as a more stringent criterion may be applied to construct means-plus-function claim, if the claims of a patent drafted in means-plus-function language, are revised to include the structure of the elements disclosed in the specification, the claims could be more strictly interpreted on the basis of the literal wording of the claims.