Patent ID: 7789566

Claim:
A dynamical pressure bearing device, comprising: a shaft having a first bearing surface and a first portion exteriorly adjacent to the first bearing surface; a sleeve having a second bearing surface and a second portion exteriorly adjacent to the second bearing surface, the sleeve being rotatably engaged with the shaft with a clearance; a dynamical pressure generation groove formed on at least one of the first bearing surface and the second bearing surface; a lubricant filled in the clearance; and an oil repellent film formed on at least one of the first portion and the second portion, the oil repellent film comprising: a fluorine polymer having a perfluoroalkyl group; and a chromogenic substance which makes color development in blue at UV irradiation, wherein the fluorine polymer is included at an amount of 0.05 to 30 weight % in the total amount of the fluorine polymer, the chromogenic substance and the solvent, wherein the chromogenic substance is included at an amount of 500 to 10000 wt ppm in the total amount of the fluorine polymer, the chromogenic substance and the solvent, wherein the chromogenic substance is represented by Formula (A) or Formula (B): wherein R 1 to R 8 independently represent hydrogen, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6 , an aryl group having an aryl carbon number of 6 to 18, and hydroxyl group, or wherein R 1 to R 14 independently represent hydrogen, an alkyl group having a carbon number of 1 to 6, an alkoxy group having a carbon number of 1 to 6, an aryl group having an aryl carbon number of 6 to 18, and hydroxyl group.