November, 2015｜News Letter

1. How should Claimed Element Corresponding to Conventional Art be Interpreted?Nippon Steel & Sumitomo Metal Corporation. v. Dow Corning Toray Co., Ltd., Case No. 2014 (Ne) 10082 (Decision rendered on November 5, 2015)

The Patentee, Nippon Steel & Sumitomo Metal (NSSM), obtained a patent relating to a method for producing 4H type single-crystalline silicon carbide in 2004, and filed an infringement suit based on the patent against Dow Corning Toray (DCT) with the Tokyo District Court in 2011. The Tokyo District Court dismissed the NSSM's demand on the grounds of non-infringement of the patent in 2014. NSSM appealed against the Tokyo District Court's decision to the IPHC in 2014.

Claim 1 of the NSSM's patent at issue claims as follows:
A method for producing an ingot of 4H type single-crystalline silicon carbide, comprising introducing 5 x 10¹⁸ cm^-3 or more and 5 x 10¹⁹ cm^-3 or less of nitrogen at the positions of carbon atoms when single-crystalline silicon carbide is grown by a sublimation-recrystallization method using a seed crystal.

One of the main issues in this case lied in how a claimed element corresponding to a conventional art should be interpreted in an infringement suit. The IPHC answered to the issue as follows:

In the decision of the 1st instance, the Tokyo District Court interpreted the claimed term "sublimation-recrystallization method" as meaning sublimating a polycrystalline solid material which consisted of the same substance as the product, and then crystallizing the material again to obtain a single-crystalline product; and decided that DCT did not infringe the patent at issue since the accused DCT's method did not fall into the claimed "sublimation-recrystallization method".

However, having reviewed the specification of the patent at issue and prior art references in detail, the IPHC made two findings. First, the claimed invention of the patent at issue corresponded to a conventional growth method of 4H type single-crystalline silicon carbide except for the technical feature of "introducing a specific amount of nitrogen at the positions of carbon atoms". Second, it had been known at the time of filing the patent at issue to use silicon and carbon as the starting material, react them to produce crystalline silicon carbide, and then sublimate the produced silicon carbide to form single-crystalline silicon carbide on the seed crystal, although it was acknowledged that an embodiment using silicon carbide solid (powder) as the starting material was a general one and only an embodiment using silicon carbide was demonstrated as a working example in the specification of the patent at issue. On the basis of the above findings, the IPHC interpreted the claimed term as including not only an embodiment using silicon carbide solid (powder) as the starting material, which was demonstrated in the specification of the patent at issue, but also an embodiment using silicon and carbon as the starting material, reacting them to produce a crystalline silicon carbide, and then sublimating the produced silicon carbide to form a single-crystalline silicon carbide on the seed crystal. Accordingly, the IPHC decided that the accused DCT's method fell into the patent at issue since the accused DCT's method used silicon and carbon as the starting material and it was experimentally confirmed that silicon carbide was produced during the accused DCT's method.

Conclusively, the IPHC overturned the Tokyo District Court's decision and judged that DCT infringed the patent at issue.

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

K&P’s CommentsAs seen from the above decision, a claimed element corresponding to a conventional art is likely to be interpreted broadly even if the disclosures of the specification of a patent including working examples are not so detailed.

In November 2015, the IPHC handed down 17 decisions including the above case on patent, and overturned the previous decisions in 5 cases.

In November 2015, the IPHC handed down 4 decisions on trademark, and overturned the previous decisions in 2 cases.