Opinion ID: 174530
Heading Depth: 3
Heading Rank: 1

Heading: “Insulating Material”

Text: The district court construed “insulating material” as follows: a material with poor electrical conduction that acts to suppress switching noise generated by a pulse width modulation control of the direct driving motor, thereby suppressing the video screen and audio noise caused by electrical noise produced by the capstan motor. Daewoo argues that the court’s definition of insulating material as a material having “poor electrical conduction” renders the claim construction fatally flawed because it improperly uses comparative language. Daewoo states that the district court in its claim construction merely replaced one vague term (“insulating”) with an even vaguer term (“poor electrical conduction”). Daewoo argues that the word “poor” is a comparative term, raising but not answering the question of “poor relative to what?” Daewoo states that an adequate definition of “insulating material” requires a numerical resistivity limit, such as 107 ohm-cm or greater, 13 FUNAI ELECTRIC v. DAEWOO ELECTRONICS which corresponds to the resistivity of materials illustrated in the ’210 specification, in order to provide certainty and clarity to the claims. Funai responds that “poor electrical conduction” adequately describes the insulating material used in this context, and that a person of ordinary skill in the field of insulating motors and reading the specification would have no trouble understanding what is covered by the claim. Daewoo also argues that the district court’s further description of “insulating material” as a material that “acts to suppress switching noise generated by a pulse width modulation control of the direct driving motor” is “functional” and therefore “circular,” and thus improper. In response Funai points to the specification’s statement that the insulating material suppresses such noise, as supporting the court’s construction. The use of comparative and functional language to construe and explain a claim term is not improper. A description of what a component does may add clarity and understanding to the meaning and scope of the claim. The criterion is whether the explanation aids the court and the jury in understanding the term as it is used in the claimed invention. There was evidence in the district court that persons experienced in this field would understand this description of the insulating material, in the context in which it is used, as a poor electrical conductor serving the function set forth in the claim. No error can be attributed to this use of comparative and functional explanation in construing these claims.