Introduction of Precedent on Inventive Step Related to Inventions Defined by Numerical Limitation [Review of Supreme Court’s judgment 2016hu380 announced on July 12, 2018]
1. Introduction A recent Supreme Court precedent in relation to deciding inventive step of an invention defined by numerical limitation was decided as follows, so a path has been opened for inventive step to be recognized without the following stipulation regarding critical significance: “In the case that a numerical limitation in a patent invention is merely a supplementary matter since another composition that can be recognized for inventive step is added to the patent invention, or even if the compositions of two inventions are the same besides a numerical limitation, if such numerical limitation has its meaning as a technical means in order to achieve a task which is totally different from that of the disclosed invention and the effect therefrom is also different, the numerical limitation has no critical significance so that the inventive step of the patent invention will not be denied (refer to Supreme Court judgment 2008hu4998 announced on August 19, 2010).” However, unlike such precedent, in practice it is very rare that inventive step is recognized for an invention defined by a numerical limitation during the actual examination phase or by court decision. Moreover, a recent Supreme Court precedent was established in a decision to deny the inventive step of an invention defined by numerical limitation. The matter is reviewed in detail below. 2. Court’s decision 2-1. Invention (patent application No. 10-2011-7025884/ title: Method for Producing Resin for Optical Material) [Claim 1] A manufacturing method which comprises the distribution of or a process (1) which distills ; and reduces the content of the total of moisture among a polythiol compound by 20 to 600ppm, and the polythiol compound in which the moisture content is 20~600ppm obtained by process (1), and mixes it with a polyiso(thio)cyanate compound; and obtains a polymerizable composition in which the moisture is 10 to 300ppm at process (2), in which the moisture content obtains the polymerizable composition of 10~300ppm, and including a process (3) which mixes; and obtains a resin for optical material as a result of the content of the moisture obtaining polymerization of the polymerizable composition of 10~300ppm through the process
2-2. Reference The Reference relates to a method for producing plastic lenses and the plastic lens disclosed in Japanese Publication No. 2006-162926 (published on June 22, 2006). 2-3. Decision on detailed matters 2-3-1. Inventive step will be denied for a patent invention announced before the filing thereof in which component range is limited by numerical value in the case that the invention’s task and effect are to the extent of the disclosed invention and only have difference in existence of a numerical limitation and also there is no significant effect without occurrance of the significant effect within that limited numerical range, as such invention is merely a simple numerical limitation which could have easily been chosen by a person having ordinary skill in the art to which the inventions pertain (hereinafter “a skilled person”) (refer to Supreme Court decision 2007hu1299 announced on November 16, 2007). 2-3-2. Claim 1 of the subject case’s invention and the reference have in common that they relate to a method for producing resin for optical materials which polymerize a polymeric composition that is acheived by mixture of a polythiol compound and a polyisocyanate compound. However, Claim 1 made a numerical limitation in relation to the water content of a ‘polymeric composition’, in which the polythiol compound and the polyisocyanate compound are mixed from ’10 to 300pm’, while a countermeasure constitution of the reference does not limit the water content of ‘polymeric composition’ specifically, but limits the ambient water content of the mixing polymeric composition to below ‘5 g/m3’. Also, Claim 1 of the subject case includes the process of reducing the water content of the ‘polythiol compound’ from 20 to 600pm through distillation or distribution of nitrogen under reduced pressure; however, a countermeasure process is not expressly described in the Reference. 2-3-3. There is no description in the specification of the subject invention to recognize that the water content of the ‘polythiol compound’ or the ‘polymeric composition’ revealed in Claim 1 has significant effect in relation to not developing lens straie or white turbidity within the numerical range. 2-3-4. In manufacturing a compound which includes isocyanate reacting sensitively to water, a moisture removal reactant, solvent or filler, etc. is used to suppress a side reaction of isocyanate and water, and also a method of distributing or distilling nitrogen under reduced pressure is used in order to remove water from the reactant. Such methods of usage were widely used technology before the filing of the subject invention, so a skilled person could have easily deduced ‘the process of reducing the content of the total of moisture among the polythiol compound and distribution of nitrogen by 20 to 600ppm’ of Claim 1 by applying well-known or commonly used art to the Reference. 2-3-5. The effect of inhibiting development of lens straie or white turbidity which Claim 1 pursues achieving by adjusting the numerical value of the water content of a polymeric composition is identically described in the Reference or is merely confirming the effect which was inherent in the technical idea of the Reference. 3. Discussion and implication Regarding the inventive step of a numerical limitation invention, the subject decision also presents “whether the distinction of a totally different or significant action effect occurs within the limited numerical range” as a standard of judgment, as have several other precedents on deciding inventive step of numerical limitation inventions (Supreme Court decision 2007hu1299 announced on November 16, 2007). If there is no description in a specification to be recognized for significant effect and it is merely confirming the effect inherent in a technical idea in a reference, inventive step will be denied. As stated above, an invention defined by numerical limitation has a high possibility of being pointed out for lack of inventive step since such invention is considered to be a simple change of design of a prior invention. Accordingly, it is considered that an invention related to the above should be prepared concretely at the stage of filing an application. Specifically, in order for such invention to be recognized for its inventive step as an invention defined by a numerical limitation of which the effect is identical with a prior invention, the technical meaning of the numerical limitation should be sufficiently described in the specification from the filing stage, along with a description of the action, effect of limitation value and data which support such effect. The Supreme Court made a decision regarding the detailed matter of the case in the same year as follows: “There are no descriptions or implication of reducing core loss by setting discharge current in both reference 2 or reference 1. Furthermore, Claim 1 of the subject case has clearly different effect compared to references which relates to reduction of core loss. Thus, even if the critical significance of a numerical limitation is not clearly shown in the specification of Claim 1 of the subject case, the technical meaning of the numerical limitation of the range of discharge current in constitution 5 of Claim 1 of the subject case will not be denied.” Namely, the Supreme Court recognized the inventive step of the case by mentioning that the effect of reduction of core loss by limiting discharge current to 2 amperes or more in the corresponding patent invention is a different effect in comparison to the references.