Lee International

[Procedural History] In a patent invalidation trial against the patent entitled “Ceramic Backing Materials” (the “Subject Patent”), the Intellectual Property Trial and Appeal Board (IPTAB) rendered a decision invalidating the patent. On an appeal, the Patent Court upheld the decision issued by the IPTAB.  However, the Supreme Court reversed the original decision on the ground that it was improper to deny the inventive step of the Subject Patent (see Supreme Court Case No. 2018 Hu 11728 issued on December 10, 2021).

[Case Summary] The Subject Patent is directed to a support for ceramic welding comprising SiO₂, Al₂O₃, MgO and CaO as the main components, having a refractory index of S.K8 to S.K12, a plastic density of 2.0 to 2.4 g/cm³ and an absorption rate of less than 3%.

In contrast, the prior art discloses a support for welding having the same main components as the Subject Patent, having a refractory index of S.K11 to S.K15 and a porosity of 20 to 40%.  That is, the Subject Patent is different from the prior art in terms of the scope of the refractory index, and the prior art does not disclose the plastic density or the absorption rate.

The prior art discloses that the porosity less than 20% is not preferred, which teaches away from the Subject Patent.  Further, the proportional relationship between the porosity and absorption rate is known in the art.  Thus, one of ordinary skill in the art could not have easily conceived lowering the porosity to less than 20% in view of the prior art, thereby lowering the absorption rate, which is proportional to the porosity, to less than 3%.

In addition, one of ordinary skill in the art could not have easily selected a low absorption rate as defined in the Subject Patent, as it would harm the connective relationship between the refractory index and the porosity in the prior art.  Further, there is no evidence supporting the effect that can be predicted from the low adsorption rate of the Subject Patent.

Accordingly, it is improper to deny the inventive step of the Subject Patent.

[Significance] It appears that the Supreme Court issued the decision with the intention of emphasizing the importance of considering the connective relationship between components in the claimed invention and the disclosure of the prior art that teaches away from the claimed invention when determining the inventive step of the claimed invention to avoid issuance of a decision based on hindsight bias.