Acoustic touch position sensor using higher order horizontally polarized shear wave propagation

A touch sensor comprising:

• a substrate capable of propagating a horizontally polarized shear-type wave having an order greater than zero, said substrate having at least one touch surface, a touch on said substrate causing a perturbation of said horizontally polarized shear-type wave;
• a transducer producing a vertically polarized transverse wave having a longitudinal component in a wave propagating area;
• means for converting said vertically polarized transverse wave having a longitudinal component propagating in said wave propagating area into said horizontally polarized shear-type wave having an order greater than zero propagating in said substrate;
• and
• means for sensing a touch-induced perturbation of said horizontally polarized shear-type wave.

A touch position sensor comprising:

• a substrate having at least one touch surface and being capable of propagating an acoustic wave having a horizontal shear-type component substantially parallel to said surface, having a non-uniform volumetric energy density along a vertical axis normal to said surface and having energy at said surface;
• means for reflecting portions of a wave having a longitudinal component as at least an acoustic wave having a horizontal shear-type component substantially parallel to said surface, having a non-uniform volumetric energy density along a vertical axis normal to said surface and having energy at said surface, having an axis, along paths having differing displacements along said axis, said reflecting means being disposed on said substrate;
• means for generating a wave having longitudinal component, propagating in said substrate in a direction along said axis of said reflecting means, a touch on said substrate touch surface perturbing said acoustic wave;
• and
• means for sensing the time of occurrence of a perturbation.

A touch sensor comprising:

• a substrate having at least one touch surface and being capable of propagating an acoustic wave having a horizontal shear-type component substantially parallel to said surface, having a non-uniform volumetric energy density along a vertical axis normal to said surface and having energy at said surface;
• first means for reflecting portions of a wave having a longitudinal component as a first acoustic wave having a horizontal shear-type component substantially parallel to said surface, having a non-uniform volumetric energy density along a vertical axis normal to said surface and having energy at said surface along first paths having differing displacement along a first axis of said first reflecting means;
• and
• second means for reflecting portions of a wave having a longitudinal component as a second acoustic wave having a horizontal shear-type component substantially parallel to said surface, having a non-uniform volumetric energy density along a vertical axis normal to said surface and having energy at said surface along first paths having differing displacement along a second axis of said second reflecting means.

An object proximity sensor comprising:

• a substrate having first and second generally parallel edges, and a top touch surface and being capable of propagating an acoustic wave having a horizontal shear-type component substantially parallel to said surface, having a non-uniform volumetric energy density along a vertical axis normal to said surface and having energy at said surface;
• a first transmitting transducer coupled to a surface of said substrate and responsive to a drive signal for imparting a wave having a longitudinal wave component into said substrate, said wave propagating along a first axis parallel to said first edge;
• a first array of reflective elements disposed along said first axis and adjacent to said first edge, said reflective elements being positioned to reflect portions of said wave having a longitudinal wave component along first, substantially parallel paths as an acoustic wave having a horizontal shear-type component substantially parallel to said surface, having a non-uniform volumetric energy density along a vertical axis normal to said surface and having energy at said surface, a touch on said substrate top touch surface forming a perturbation in said acoustic wave propagating along a first path intersecting the position of the touch;
• and
• a drive signal generator connected to said first transmitting transducer.

A method of detecting an object, comprising:

• providing a substrate having at least one touch surface and being capable of propagating an acoustic wave having a horizontal shear-type energy component substantially parallel to said surface, having a nonuniform volumetric energy density along a vertical axis normal to said surface and having energy at said surface;
• inducing a first acoustic wave having a longitudinal component along a first axis in the substrate, the first axis being parallel to said surface;
• reflecting, as a second acoustic wave, portions of the energy of the first acoustic wave, the second acoustic wave having a horizontal shear-type energy component substantially parallel to the surface, having a nonuniform volumetric energy density along a vertical axis normal to the surface, and having energy at the surface, the second acoustic wave being directed along a second axis in the substrate, different than the first axis, and being parallel to said surface;
• perturbing said second acoustic wave by placing an object in proximity to said surface of the substrate;
• and
• detecting the perturbed second acoustic wave.