Vibration actuator with improved contact surface

Abstract

A vibration actuator has a vibration element which generates vibrations and has a contact surface. The vibration actuator further has a relative motion member which moves in a movement direction with respect to the vibration element upon generation of vibrations by the vibration element. The relative motion member has a contact surface which is in compressive contact with the contact surface of the vibration element. At least one of the contact surface of the vibration element and the contact surface of the relative motion member is polished to have a plural streaky scratches. The plural streaky scratches may be in a principle direction which is in a direction other than a direction at a right angle with respect to the movement direction. In this case, the principle direction may be at angle with respect to the movement direction. Alternatively, the principle direction may be approximately parallel to the movement direction. As an alternative to being formed in the principle direction, the plural streaky scratches may be formed in irregular directions or formed in irregular circular arcs. The at least one contact surface polished to have streaky scratches may have center line average height Ra which is a maximum in a rough direction and is within the range 0.05 .mu.m.ltoreq.Ra.ltoreq.1.0 .mu.m.