Method and apparatus for generating a vibrational stimulus

• US 20060015045A1
• Filed: 07/22/2005
• Published: 01/19/2006
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: Engineering Acoustics Incorporated
• Original Assignee: Engineering Acoustics Incorporated
• Inventors: Zets, Gary A., Chapman, Frank D., Ensign, Thomas H., Mortimer, Bruce J.P.
• Granted Patent: US 7,798,982 B2
• Time in Patent Office: Days
• US Class Current: 601/78
• CPC Class Codes: A61H 2201/5005 for controlling frequency distribution, modulation or interference of a driving signal
• CPC Class Codes: A61H 2201/5007 computer controlled
• CPC Class Codes: A61H 23/0218 with alternating magnetic fields producing a translating or oscillating movement

Abstract

A vibrotactile transducer provides a point-like vibrational stimulus to the body of a user in response to an electrical input. The apparatus includes a housing held in contact with the skin and a moving mechanical contactor protruding through in an opening in said housing and preloaded into skin. The contactor is attached to a torroidal moving magnet assembly suspended by springs in a magnetic circuit assembly consisting of a housing containing a pair of electrical coils. The mass of the magnet/contactor assembly and the compliance of the spring are chosen so that the electromechanical resonance of the motional masses, when loaded by a typical skin site on the human body, are in a frequency band where the human body is most sensitive to vibrational stimuli. By varying the drive signal to the vibrotactile transducer and activating one or more transducer at specific location on the body using an appropriate choice of signal characteristics and/or modulation, different information can be provided to a user in a intuitive, body referenced manner.

Claims

1. A vibrotactile transducer to provide a vibrational stimulus to the body of the user in response to an electrical input, said vibrotactile transducer comprising;

a housing having a skin contacting face with an opening in it;

a toroidal moving magnetic assembly;

at least one spring suspending said assembly in said housing;

a mechanical contactor connected to said magnet assembly for movement therewith, said contactor, in its rest position, protruding from said housing face though said opening whereby, when the housing face is pressed against the skin of the user, the contactor and magnet assembly are displaced with respect to the housing to pre-load the contactor and magnet assembly against the action of the spring, the range of movement of the contactor being such that once pre-loaded it vibrates between a retracted position within the housing and an extended position in which it is in contact with the skin of the user through said opening;

a radial gap between the contactor and a face of the housing which bounds said opening; and

a magnetic circuit including a pair of electrical coils connected in a push-pull configuration whereby magnetic fields induced by current flowing in said coils vibrates said magnetic assembly and said mechanical contactor.

2. The vibrotacticle transducer of claim 1 wherein the area of said skin contacting face of the moving mechanical contactor is between about 0.1 cm sq. and 2 cm sq.

3. The vibrotactile transducer of claim 1 wherein the ratio of the mass of the mechanical contactor to the total mass of the transducer including the contactor, lies in the range 1:

5 to 2;

5.

4. The vibrotactile transducer of claim 1 including means for applying a carrier signal to said coils for vibrating said moving magnetic assembly and said contactor at a frequency of between about 200 Hz and about 300 Hz, and for generating a signal which modulates the carrier signal at a frequency of between about 0.1 Hz and about 70 Hz.

5. The vibrotactile transducer of claim 1 including means for selectively applying signals to said coils to vibrate said assembly and said contactor at a first frequency and at a second frequency, the first and second frequencies being different to one another.

6. The vibrotactile transducer of claim 1 including a plurality of holes in said housing to allow flooding of the housing upon the transducer being immersed in a liquid, said holes covering between about 8% and 15% of the area of the front and rear faces of the transducer.

7. The combination of a plurality of vibrotactile transducers as claimed in claim 1 and means for vibrating the contactors at different frequencies and at different times whereby different parts of the user'"'"'s body can be stimulated in different ways.

8. The combination of a plurality of vibrotactile transducers as claimed in claim 1 and means for vibrating the contactors at different intensities and at different times whereby different parts of the user'"'"'s body can be stimulated in different ways.

9. A vibrotactile transducer to provide a vibrational stimulus to the body of the user in response to an electrical input, said vibrotactile transducer comprising;

a housing having a skin contacting face with an opening in it;

a toroidal moving magnetic assembly;

at least one spring suspending said assembly in said housing;

a mechanical contactor connected to said magnet assembly for movement therewith and positioned in said opening for vibratory movement through said opening, the range of movement of the contactor being such that it vibrates between a retracted position within the housing and an extended position in which it is in contact with a zone of the skin of the user through said opening, said zone being encircled by said face,

a radial gap between the contactor and a surface of the housing which bounds said opening; and

a magnetic circuit including a pair of electrical coils connected in a push-pull configuration whereby magnetic fields induced by current flowing in said coils vibrates said magnetic assembly and said mechanical contactor.

10. The vibrotacticle transducer of claim 9 wherein the area of said skin contacting face of the moving mechanical contactor is between about 0.1 cm sq. and 2 cm sq.

11. The vibrotactile transducer of claim 9 wherein the ratio of the mass of the mechanical contactor to the total mass of the transducer including the contactor, lies in the range 1:

5 to 2;

5.

12. The vibrotactile transducer of claim 9 having means for applying a carrier signal to said coils for vibrating said moving magnetic assembly and said contactor at a frequency of between about 200 Hz and about 300 Hz, and for generating a signal which modulates the carrier signal at a frequency of between about 0.1 Hz and about 70 Hz.

13. The vibrotactile transducer of claim 9 including means for selectively applying signals to said coils to vibrate said assembly and said contactor at a first frequency and at a second frequency, the first and second frequencies being different to one another.

14. The vibrotactile transducer of claim 9 having a plurality of holes in said housing to allow flooding of the housing upon the transducer being immersed in a liquid, said holes covering between about 8% and 15% of the area of the front and rear faces of the transducer.

15. The combination of a plurality of vibrotactile transducers as claimed in claim 9 and means for vibrating the contactors at different frequencies and at different times whereby different parts of the user'"'"'s body can be stimulated in different ways.

16. The combination of a plurality of vibrotactile transducers as claimed in claim 9 and means for vibrating the contactors at different intensities and at different times whereby different parts of the user'"'"'s body can be stimulated in different ways.

17. The vibrotactile transducer of claim 9 including two individual electrical coils that 10 can be connected in series, parallel or independently to present a 4:

1 impedance range to the drive circuitry.

18. The vibrotactile transducer of claim 9 wherein the mass of the moving contactor assembly, the mass of the housing, the compliance of the skin load on the contactor face and housing face, and the compliance of the spring in the direction of motion are chosen so that the electromechanical resonance of the motional masses, when loaded by a typical skin site on the human body, are in a frequency band where the human body is most sensitive to vibrational stimuli.

19. A method for providing a vibrational stimulus to the body of the user in response to an electrical input, said method comprising the steps of:

providing a vibrotactile transducer having a housing with a skin contacting face with an opening in it, a toroidal moving magnetic assembly, at least one spring suspending the assembly in the housing, and a mechanical contactor connected to the magnet assembly for movement therewith and positioned in the opening for vibratory movement through the opening;

providing a magnetic circuit including a pair of electrical coils connected in a push-pull configuration whereby magnetic fields induced by current flowing in the coils vibrates the magnetic assembly and moves the mechanical contactor between a retracted position within the housing and an extended position in contact with a zone of the skin of the user through the opening, the zone being encircled by the face.

20. The method of claim 19 further including the step of applying a carrier signal to the coils for vibrating said moving magnetic assembly and the contactor at a frequency of between about 200 Hz and about 300 Hz, and for generating a signal which modulates the carrier signal at a frequency of between about 0.1 Hz and about 70 Hz.

21. The method of claim 19 further including the step of selectively applying signals to the coils to vibrate the assembly and the contactor at a first frequency and at a second frequency, the first and second frequencies being different to one another.

22. The method of claim 19 further including the step of providing a plurality of vibrotactile transducers, and vibrating the contactors at different frequencies and at different times whereby different parts of the user'"'"'s body can be stimulated in different ways.

23. The method of claim 19 further including the step of providing a plurality of vibrotactile transducers, and vibrating the contactors at different intensities and at different times whereby different parts of the user'"'"'s body can be stimulated in different ways.

24. The method of claim 19 further including the step of choosing the mass of the moving contactor assembly, the mass of the housing, the compliance of the skin load on the contactor face and housing face, and the compliance of the spring in the direction of motion so that the electromechanical resonance of the motional masses, when loaded by a typical skin site on the human body;

are in a frequency band where the human body is most sensitive to vibrational stimuli.