Dynamical pressure bearing device, motor, and recording disc driving device

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.