Ceramic dynamic-pressure bearing, motor having bearing, hard disk drive, polygon scanner, and method for manufacturing ceramic dynamic-pressure bearing

A ceramic dynamic-pressure bearing comprising a spindle having a rotary surface and a bearing having a rotary surface, said bearing being fitted on the spindle with a gap formed therebetween, in which, when either the spindle or the bearing serving as a rotation body rotates relative to the other, the rotary surfaces of the spindle and the bearing come into a non-contacting state, characterized in that

• at least the rotary surface of the spindle and/or the bearing is formed of a ceramic having a surface porosity of 10 to 60%,
• at least a portion of at least either the spindle and the bearing comprises an electrically conductive ceramic, and
• dynamic-pressure grooves are formed on the rotary surface of the spindle and/or the bearing comprising an electrically conductive ceramic such that, on a cross section of a dynamic-pressure groove taken perpendicular to a longitudinal direction of the groove, a curvature portion having a radius of 3-7 μm is formed at a position where a groove sidewall surface and a groove bottom surface meet.