Method and apparatus for providing tactile sensations
The present disclosure concerns a method and apparatus for the creation of an acoustic field for providing tactile sensations. More particularly, but not exclusively, this disclosure concerns a method and apparatus for the creation of an acoustic field providing tactile sensations for use with an interactive device. The disclosure provides a method of generating a tactile sensation. The method comprises the steps of providing a plurality of acoustic transducers arranged to generate a predetermined distribution of pressure patterns, wherein the pressure patterns comprise a first region providing a first tactile sensation and a second region providing a second, different, tactile sensation.
1. A method of generating a tactile sensation comprising the steps of:
providing a plurality of ultrasonic transducers arranged to generate a predetermined distribution of non-surface pressure patterns in mid-air using an ultrasonic carrier frequency modulated at a frequency that is detectable by a human hand;
wherein the pressure patterns comprise a first non-surface region comprising a focal point for a plurality of acoustic waves modulated at a first frequency providing a first tactile mid-air sensation on the human hand, and a second non-surface region comprising a focal point for a plurality of acoustic waves modulated at a second frequency providing a second tactile mid-air sensation on the human hand;
tracking a location of the human hand by a tracking device;
wherein the first frequency is different than the second frequency;
wherein the first tactile mid-air sensation is different than the second tactile mid-air sensation;
wherein the pressure patterns are created using a modeling algorithm having three steps, wherein the first step of the modeling algorithm comprises calculating an acoustic field for a selected transducer within the plurality of ultrasound transducers to create a modeled volume;
wherein the second step of the modeling algorithm comprises defining a plurality of control points within the modeled volume to create a first modeled acoustic field; and
wherein the third step of the modeling algorithm comprises creating a second modeled acoustic field by calculating optimal phases using a minimum norm solver so that the second modeled acoustic field is close to the first modeled acoustic field.
2. The method as in claim 1 , further comprising a gradient in amplitude within the acoustic field to simulate an edge of a virtual shape.
3. The method as in claim 1 , wherein one of the plurality of control points is a point of maximum intensity.
4. The method as in claim 1 , wherein one of the plurality of control points is a null point.
5. The method as in claim 1 , wherein a first of the plurality of control points is defined with a first modulation frequency and a second of the plurality of control points is defined with a second modulation frequency.
6. The method as in claim 1 , wherein the third step further comprises calculating a plurality of iterative optimal phases to determine the highest intensity for the plurality of control points.
7. The method as in claim 1 , wherein the plurality of control points are assigned by a user.
8. The method as in claim 1 , wherein the plurality of control points are assigned by an automated process.