Patent ID: 6104587
Filing Date: 2000-08-15
Classification: H01C,H01L

Abstract:
An electrical device which comprises(A) a resistive element which(1) exhibits PTC behavior,(2) is composed of a conductive polymer composition comprising polyvinylidene fluoride, and dispersed therein, a particulate conductive filler comprising carbon black,(3) has a planar shape with first and second major surfaces, and(4) has a thickness of at most 0.51 mm ; and(B) first and second electrodes, each of which(1) has a thickness of at least 0.060 mm, and(2) comprises(a) a base layer which comprises a first metal,(b) a surface layer which (i) comprises a second metal, (ii) has a center line average roughness R.sub.a of at least 1.3, and (iii) has a reflection density R.sub.d of at least 0.60, and(c) an intermediate metal layer which (i) is positioned between the base layer and the surface layer, and (ii) comprises a metal which is different from the first metal,the first and second electrodes being attached to the first and second major surfaces to sandwich the resistive element so that the surface layers thereof are in direct physical contact with the conductive polymer of the resistive element; andsaid device having(1) a resistivity at 20.degree. C. of at most 5 ohm-cm;(2) a resistance at 20.degree. C. of at most 5 ohms; and(3) a ratio of element thickness to electrode thickness of 6:1 to 10:1.