Surface acoustic wave actuator, and magnetic disk device and optical disk device using the same

A surface acoustic wave actuator comprising:

• a vibrator;
• a first unidirectional interdigital transducer disposed on said vibrator for exciting a surface acoustic wave;
• a second unidirectional interdigital transducer disposed on said vibrator for electrically converting the surface acoustic wave;
• an electrical combiner having an input port coupled to an external power supply and said second unidirectional interdigital transducer, and an output port connected to said first unidirectional interdigital transducers;
• a relative movement member for relative movement to said vibrator;
• and
• means for generating contact pressure between said vibrator and said relative movement member.

A surface acoustic wave actuator comprising:

• first and second unidirectional interdigital transducers;
• a vibrator on which said unidirectional interdigital transducers are disposed in a way to have one of said unidirectional interdigital transducers electrically convert surface acoustic waves excited by the other of said unidirectional interdigital transducers;
• a relative movement member for providing relative movement to said vibratory;
• a switch for changing a combination of connections of said first and second unidirectional interdigital transducers to the input and output ports of said electrical combiner;
• an electrical combiner to which said switch is connected, and an external power supply also to be connected to its remaining input port;
• and means for generating contact pressure between said vibrator and said relative movement member.