Applications of acoustic waves in data storage devices

1 . A device, comprising:

a head, having an interfacing surface that faces a medium surface, to couple energy between said interfacing surface and the medium surface; and

an acoustic transducer, engaged to said head, to generate an acoustic wave that propagates to at least a portion of said interfacing surface, said transducer configured to produce acoustic waves which reduce particles adhered to said interfacing surface.

2 . The device as in claim 1 , wherein said acoustic transducer is a type that generates a surface acoustic wave on said interfacing surface.

3 . The device as in claim 2 , wherein said acoustic transducer includes a piezoelectric layer and an interdigital electrode layer in contact with said piezoelectric layer.

4 . The device as in claim 3 , wherein said interdigital electrode layer includes concentric interdigital electrodes.

5 . The device as in claim 4 , wherein said interdigital electrodes have different arc angles with respect to a center of curvature common to said electrodes.

6 . The device as in claim 2 , wherein said acoustic transducer is engaged to said interfacing surface.

7 . The device as in claim 6 , further comprising an acoustic sensor engaged to said interfacing surface to detect a change in said acoustic wave.

8 . The device as in claim 6 , further comprising an acoustic reflector engaged to said interfacing surface to reflect said acoustic wave back to said acoustic transducer.

9 . The device as in claim 1 , wherein said acoustic transducer is a type that generates a bulk acoustic wave.

10 . The device as in claim 1 , further comprising an acoustic sensor engaged in said head at a position to detect a change in the acoustic field produced by said acoustic transducer.

12 . The device as in claim 1 , wherein said energy includes an optical signal.

13 . The device as in claim 1 , wherein said energy includes a magnetic signal.

14 . The device as in claim 1 , wherein said head has a structure to couple said energy via an evanescent field between said interfacing surface and the medium surface.

15 . The device as in claim 1 , wherein said head includes a solid immersion lens having a spherical surface to receive an optical beam and a flat surface to couple said optical beam to the medium surface.

16 . The device as in claim 15 , wherein said acoustic transducer is engaged to said spherical surface.

17 . The device as in claim 15 , wherein said acoustic transducer is engaged to said flat surface.

18 . A device, comprising:

an optical head, having an optically transparent interfacing surface that faces a medium surface of an optical storage disk, to couple radiation energy between said interfacing surface and the medium surface through a location on the interfacing surface; and

an acoustic transducer formed adjacent said interfacing surface of said optical head to generate a surface acoustic wave and to focus the surface acoustic wave to said location on said interfacing surface at an acoustic intensity greater than an acoustic intensity at said acoustic transducer.

19 . The device as in claim 18 , wherein said acoustic transducer includes a piezoelectric layer and an interdigital electrode layer of multiple interdigital electrodes in contact with said piezoelectric layer.

20 . The device as in claim 19 , wherein said interdigital electrodes are arc shaped and are concentric with respect to a center near or at said location on said interfacing surface where the radiation energy passes through.

21 . The device as in claim 20 , wherein said interdigital electrodes have different electrode lengths.

22 . The device as in claim 20 , wherein said electrode lengths are set to reduce a spatial variation of the acoustic intensity near said location on said interfacing surface.

23 . The device as in claim 20 , wherein ends of said interdigital electrodes on one side of said acoustic transducer have a shape to form a curved contour.

24 . The device as in claim 20 , wherein said interdigital electrodes respectively form different arc angels with respect to said center.

25 . The device as in claim 24 , wherein said arc angles of said interdigital electrodes linearly increase with the radius of curvature.

26 . The device as in claim 24 , wherein said arc angles of said interdigital electrodes nonlinearly increase with the radius of curvature.

27 . The device as in claim 18 , further comprising an acoustic sensor to detect a change in said surface acoustic wave on said interfacing surface to determine whether said optical head is in contact with the medium surface.

28 . The device as in claim 18 , wherein said optical head is configured to also couple a magnetic signal to and from the medium surface.

29 . The device as in claim 18 , wherein said optical head includes a solid immersion lens which has a spherical surface and an opposing flat surface.

30 . The device as in claim 29 , wherein said interfacing surface is a portion of said flat surface.

31 . The device as in claim 29 , further comprising a transparent mesa formed on said fat surface and having a flat surface as said interfacing surface.

32 . The device as in claim 31 , further comprising a magnetic coil formed over said flat surface to surround said mesa.

33 . The device as in claim 18 , said optical head produces a numerical aperture that is greater than unity with respect to the storage disk.

34 . A device, comprising:

an optical head, having an optically transparent interfacing surface that faces a medium surface of an optical storage disk, to couple radiation energy between said interfacing surface and the medium surface through a location on the interfacing surface, said optical head including a solid immersion lens which has a spherical surface and an opposing flat surface, said flat surfacing facing the medium surface; and

an acoustic transducer engaged to said spherical surface of said solid immersion lens to generate an acoustic wave to propagate through said solid immersion lens to said flat surface.

35 . The device as in claim 34 , wherein said head produces a numerical aperture that is greater than unity with respect to the storage disk.

36 . The device as in claim 34 , wherein said acoustic transducer includes a piezoelectric layer and an interdigital electrode layer of multiple interdigital electrodes in contact with said piezoelectric layer.

37 . The device as in claim 36 , wherein said interdigital electrodes conform to said spherical surface.

38 . The device as in claim 34 , wherein said acoustic transducer has an opening to allow transmission of the radiation energy in said solid immersion lens.

39 . The device as in claim 34 , further comprising an acoustic sensor to detect a change in said acoustic wave to determine whether said optical head is in contact with the medium surface.

40 . The device as in claim 34 , wherein said optical head is configured to also couple a magnetic signal to and from the medium surface.

41 . The device as in claim 34 , wherein said interfacing surface is a portion of said flat surface.

42 . The device as in claim 34 , further comprising a transparent mesa formed on said flat surface and having a flat surface as said interfacing surface.

43 . The device as in claim 42 , further comprising a magnetic coil formed over said flat surface to surround said mesa.

44 . A method, comprising:

using a recording head, which has an interfacing surface that faces a medium surface, to couple energy between said interfacing surface and the medium surface; and

generating an acoustic wave, by using an acoustic transducer engaged to said head, to propagate to at least a portion of said interfacing surface to reduce particles adhered to said interfacing surface.

45 . The method as in claim 44 , further comprising controlling an acoustic frequency of said acoustic wave to control a normal displacement of a portion of said interfacing surface to contact the medium surface.

46 . The method as in claim 44 , further comprising modulating the acoustic frequency between a high frequency at which the normal displacement is sufficient to cause the contact and a low frequency at which the normal displacement is not sufficient to cause the contact.

47 . The method as in claim 44 , wherein the acoustic wave is pulsed.

48 . The method as in claim 44 , wherein the acoustic wave is continuous.

49 . The method as in claim 44 , further comprising detecting a change in the field of the acoustic wave to determine whether the recording head is in contact with the medium surface.

50 . The method as in claim 44 , wherein the acoustic wave is a surface wave on said interfacing surface.

51 . The method as in claim 50 , wherein the acoustic transducer includes a piezoelectric layer and an interdigital electrode layer of multiple interdigital electrodes in contact with said piezoelectric layer, and wherein said interdigital electrodes are arc shaped and are concentric with respect to a center near or at said location on said interfacing surface where the radiation energy passes through.

52 . The method as in claim 51 , wherein said interdigital electrodes have different electrode lengths.

53 . The method as in claim 51 , wherein said electrode lengths are set to reduce a spatial variation of the acoustic intensity near said location on said interfacing surface.

54 . The method as in claim 51 , further comprising making ends of said interdigital electrodes on one side of said acoustic transducer a curved contour.

55 . The method as in claim 51 , further comprising making said interdigital electrodes respectively form different arc angles with respect to said center.

56 . The method as in claim 55 , wherein said arc angles of said interdigital electrodes linearly increase with the radius of curvature.

57 . The method as in claim 55 , wherein said arc angles of said interdigital electrodes nonlinearly increase with the radius of curvature.

58 . The method as in claim 44 , wherein the acoustic wave is a bulk wave.