특허유효추정원칙: Microsoft v. i4i 판례 평석

The U.S. Patent Act provides that “[a] patent shall be presumed valid” and that “[t]he burden of establishing invalidity of a patent or any claim thereof shall rest on the party asserting such invalidity.” 35 U.S.C. § 282. However the provision is silent on whether the asserting party shall prove invalidity by “clear and convincing evidence” or by “preponderance evidence”. This paper analyzes Microsoft v. i4i case, which dealt with the choice between the two rules. In the case, two parties argued four main issues: (1) case law; (2) legislative intent of the Congress; (3) need for deference on expertise of the examiner; and (4) protection of trust interest of a patentee. The U.S. Supreme Court held: (1) precedents preferred clear and convincing evidence rule regardless of whether or not the prior art was considered by the examiner, (2) the Congress chose clear and convincing evidence rule through the 1952 amendment, (3) even though there is doubt on the quality of examinations, the expertise of examiner still must be deferred, and (4) considering the investment made by the patentee, the trust interest of the patentee better be protected. Microsoft v. i4i decision supports clear and convincing evidence rule and further supports patent effectiveness and patentee’s trust interest, thereby consequently enhancing strength of patent right. In 2011 in Korea, the patentees’ winning rate in patent litigations is too low. Some statistics indicates the winning rate between 20% and 26%. Considering such situation, it is claimed that the U.S. clear and convincing evidence rule may be imported to the Korean patent jurisprudence. It is authors’ hope that this paper may give some guidance in such importation.