September, 2020｜News Letter

1. How should Support Requirement be Examined?

JFE Steel Corporation v. Nippon Steel Corporation; Case No. 2019 (Gyo-Ke) 10128 (Decision rendered on September 29, 2020)

The Patentee, Nippon Steel (NS), obtained a patent relating to a low core loss grain-oriented electromagnetic steel sheet in 2013. Against the NS’s patent, JFE Steel (JFES) filed an invalidation trial with the JPO in 2018. The JPO dismissed the JFES’s demand in 2019. JFES filed an appeal against the JPO's decision to the IPHC in 2019.

Claim 1 of the NS’s patent at issue claims as follows:
A low core loss grain-oriented electromagnetic steel sheet, wherein regions, where stress in the thickness direction being a tensile stress, and having a maximum value of 40 MPa or more and equal to or less than the yield stress value of the steel sheet material exists, are formed at an interval of 7.0 mm or less in the rolling direction of the steel sheet in one or more locations in the inner part of the thickness of the steel sheet.

One of the main issues in this case related to how the support requirement should be examined. The IPHC answered to the issue as follows:

First, having reviewed the disclosure of the detailed description of the invention in the specification of the patent at issue in detail, the IPHC found (a) that it is recognized that the problem to be solved by the invention of providing “an excellent grain-oriented magnetic steel sheet“ is resolved,
(i) by adopting a constitution of forming regions, where stress in the thickness direction being a tensile stress, and having a maximum value of 40 MPa or more and equal to or less than the yield stress value of the steel sheet material exists, are formed at an interval of 7.0 mm or less in the rolling direction of the steel sheet in the inner part of the thickness of the steel sheet, and (ii) by controlling the distortion and stress distribution not only in the surface, but also in the inner part of the thickness under quantitatively adequate conditions by separating the core loss of the grain-oriented magnetic steel sheet into hysteresis loss and eddy current loss, in particular,
from the viewpoint of eddy current loss due to magnetic domain subdivision; (b) that Claim 1 of the patent at issue is intended to reduce the core loss of the grain-oriented magnetic steel sheet from two points of view, namely, hysteresis loss and eddy current loss, and, in particular, it can be understood that the reduction of eddy current loss is due to magnetic domain subdivision, and that the introduction of the tensile stress results in an excellent core loss characteristics; and (c) that the "excellent grain-oriented magnetic steel sheet” is construed to mean a grain-oriented magnetic steel sheet with excellent core loss characteristics,
in light of the descriptions of the entire specification of the patent at issue, in particular, the description of "[being] able to provide a grain-oriented magnetic steel sheet with very excellent core loss characteristics”, and the description that the grain-oriented magnetic steel sheets of the examples were excellent in low core loss characteristics compared with those of the comparative examples.

On the basis of the above findings, the IPHC decided that a person skilled in the art could have recognized that the problem to be solved by each of the inventions of the patent at issue could be solved from the descriptions of the detailed description of the specification of the patent at issue. In addition, the recitation of Claim 1 of the patent at issue is described in the detailed description.

In this connection, during the court proceedings, JFES asserted that the "maximum value of the tensile stress in the thickness direction of the steel sheet is 40 MPa or more" is derived on the basis of Figure 5 of the specification of the patent at issue, and that it cannot be generalized to each of the inventions of the patent at issue on the basis of a value obtained under such specific conditions.

However, the IPHC rejected the JFES's assertion by pointing out as below:

In general, when magnetization and stress are present, an interaction energy between magnetization and stress in an electromagnetic steel sheet generates according to the following formula:
Interaction energy = -C×M×σ×cos2θ
(where C: a positive constant, M: magnitude of magnetization, σ: magnitude of stress, θ: an angle between magnetization and stress).
Further, it is theoretically explained using the above mentioned formula in the specification of the patent at issue that the interaction energy between magnetization and stress of the electromagnetic steel sheet becomes low and becomes energetically stable when θ is 0° or 180°, and that, when tensile stress is introduced in the thickness direction of the steel sheet, the magnetization becomes energetically stable if the magnetization trends in the direction of the stress, that is, in the thickness direction of the steel sheet, since σ is positive, and as a result, a closure domain is formed,
reconstruction of the magnetic domain of the entire steel sheet is promoted, the domain width is subdivided by 180 degrees, and the eddy current loss is reduced.
Of course, Figure 5 and the examples are each examples obtained under specific conditions, and considering that the above equation does not include factors of thickness and distribution width, of the magnetic steel sheet, irradiation trace width, laser spot shape, irradiation intervals, angle of the strip area with respect to the rolling direction, tensile stress in the rolling direction, composition, and contribution of irradiation conditions (air or water), interaction energy is not affected by these factors.
Further, concurrently considering the mechanism of each of the inventions of the patent at issue, even if experiments are conducted with samples where any of the various conditions, such as sheet thickness, distribution width, irradiation trace width is changed as pointed out by JFES, the interaction energy between magnetization and stress of the electromagnetic steel sheet is not affected, and therefore it cannot be considered that circumstances where mechanism of the means to solve the above mentioned problem of each of the inventions of the patent at issue is greatly impeded, or the mechanism is changed to a completely different one, would arise.
Moreover, the mechanism of suppressing the increase in hysteresis loss is that there is a relation that, when the value of the tensile stress increases above the stress in a plastic region, that is, the yield stress, the plastic region in the inner thickness of the steel sheet functions as a pinning site of a magnetic wall, and the hysteresis loss, which is a portion of the core loss increases, and therefore that the increase of the hysteresis loss can be suppressed when the maximum value of the tensile stress is not more than the yield stress, and this can be similarly understood from the descriptions of the detailed description of the invention.
As such, it can be understood that the reduction of core loss can be implemented when the “maximum value of the tensile stress in the thickness direction of the steel sheet is 40 MPa or more and equal to or less than the yield stress value of the steel sheet material”.

Conclusively, the IPHC dismissed the JFES’s appeal and upheld the JPO’s decision.

An appeal to the Supreme Court was NOT filed against this decision, and thus the decision is made final and binding.

K&P’s Comments As shown above, it would be very useful to theoretically explain the characteristic feature(s) and/or the mechanism of the claimed invention at issue in the description of the specification as filed in order to satisfy the support requirement, in particular, in the case where there are only a small number of working examples, even if it is rather uncorroborated.

(by Katsumasa OSAKI, Patent Attorney)

In September, 2020, the IPHC handed down 10 decisions including the above case on patent, and overturned the previous decision in 3 cases.

In September, 2020, the IPHC handed down 5 decisions on trademark, and maintained all the previous decisions.

In September, 2020, the IPHC handed down no decision on industrial design.