K&P's Intellectual Property High Court Decision Report in September, 2013

Kuraray Co., Ltd. v. Sekisui Chemical Co., Ltd., Case No. 2012 (Gyo-Ke) 10451 (Decision rendered on September 26, 2013)

The Patentee, Sekisui, obtained a patent relating to an interliner for a laminated glass in 2008, against which Kuraray filed an invalidation trial before the JPO in 2012 on the grounds of not satisfying the clarity requirement and the support requirement. The JPO dismissed Kuraray's demand in 2012, followed by Kuraray's appeal against the JPO's decision to the IPHC in 2012.

Claim 1 of the patent at issue claims as follows:

"An interliner for a laminated glass mainly comprising 100 parts by weight of a polyvinyl acetal resin and 20-60 parts by weights of triethylene glycol di-2-ethylhexanoate containing 0.1-5.0% by weight of triethylene glycol mono-2-ethylhexanoate, and containing 5-50 ppm of sodium (Na) and/or 5-100 ppm of potassium (K)".

The main issue in this case was how the meaning of the term "and/or" in the claim should be construed. The IPHC answered to the issue as follows.

First, the IPHC found (i) that the term "and/or" was recognized to be used to collectively mean three cases where two parallel items were present, where either one of the items were present, and where the other of the items were present, with reference to the Japanese Industry Standard (JIS), and thus (ii) that the phrase "5-50 ppm of sodium (Na) and/or 5-100 ppm of potassium (K)" in Claim 1 included (a) the case where 5-50 ppm of Na and 5-100 ppm of K were contained, (b) the case where 5-50 ppm of Na was contained, and (c) the case where 5-100 ppm of K was contained.

On the basis of the above findings, the IPHC decided (i) that it was clear that the case (a) specifically meant the case where both Na and K were contained with the amount of Na present being within the numerical range of 5-50 ppm and that of K present being within the numerical range of 5-100 ppm, and thus (ii) that it was literally natural to construe the case (b) as the case where K was NOT contained, and the case (c) as the case where Na was NOT contained, and therefore (iii) that the term "and/or" in the claim satisfied the clarity requirement.

Conclusively, the IPHC dismissed Kuraray's appeal, and upheld the conclusion of the JPO's decision.

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

Under the Japanese practice, the phrase "A and/or B" as a claim language has been construed to collectively mean "A and B", "A" in which B may or may not be contained, and "B" in which A may or may not be contained, for a long time. The Board of JPO also adopted this construction in their decision. To the contrary, the IPHC adopted the restrictive construction in the subject case as shown above. To avoid such a restrictive construction on "A and/or B", it would be advisable to separately define "A" and "B" in different claims, respectively, instead of using the phrase "A and/or B", provided that the unity of invention is satisfied.