Systems and methods for improving cartilage conduction technology via functionally graded materials

1. A cartilage conduction system comprising:

a transducer that generates mechanical energy; and

a functionally graded material (FGM) interface dimensioned to be coupled between the transducer and cartilage located on an outer ear of a user, wherein the FGM interface:

exhibits a gradation of at least one characteristic from one side of the FGM interface that is impedance-matched to the transducer to another side of the FGM interface that is impedance-matched to the cartilage located on the outer ear of the user; and

facilitates transferring the mechanical energy across the gradation of the characteristic from the transducer to the cartilage.

2. The cartilage conduction system of claim 1 , wherein the FGM interface comprises a plurality of discrete material layers that collectively form the gradation of the characteristic exhibited by the FGM interface.

3. The cartilage conduction system of claim 1 , wherein the gradation of the characteristic exhibited by the FGM interface comprises a specific gradient of the characteristic from the one side to the another side along one dimension of the FGM interface.

4. The cartilage conduction system of claim 1 , wherein the characteristic comprises at least one of:

stiffness;

loss factor;

density;

lattice spacing;

porosity;

Poisson's ratio; or

filler content.

5. The cartilage conduction system of claim 1 , wherein:

the one side of the FGM interface is coupled to the transducer;

the another side of the FGM interface is dimensioned to be coupled to the cartilage located on the outer ear of the user;

the one side of the FGM interface has a first stiffness modulus; and

the another side of the FGM interface has a second stiffness modulus that is lower than the first stiffness modulus.

6. The cartilage conduction system of claim 1 , wherein the another side of the FGM interface contours to the cartilage located on the outer ear of the user.

7. The cartilage conduction system of claim 1 , wherein the FGM interface is dimensioned to be coupled between the transducer and at least one of:

a portion of a helix of the user;

a tragus of the user;

an antihelix of the user;

a scapha of the user;

a scaphoid fossa of the user; or

a concha of the user.

8. The cartilage conduction system of claim 1 , wherein the transducer generates vibrations that:

are transferred to the cartilage located on the outer ear of the user via the FGM interface; and

cause the cartilage to generate sound pressure that propagates to an eardrum of the user.

9. The cartilage conduction system of claim 1 , wherein the FGM interface is anisotropic such that:

the FGM interface exhibits a first level of transmissibility in a direction from the transducer to the cartilage; and

the FGM interface exhibits a second level of transmissibility in an opposite direction from the cartilage to the transducer, the second level of transmissibility being lower than the first level of transmissibility.

10. The cartilage conduction system of claim 9 , wherein:

the mechanical energy comprises vibrations;

the cartilage generates sound pressure from the vibrations; and

the FGM interface prevents at least some of the vibrations from returning to the transducer in the opposite direction due at least in part to the second level of transmissibility being lower than the first level of transmissibility.

11. The cartilage conduction system of claim 1 , further comprising an FGM suppressor that at least partially encompasses a portion of the transducer coupled to the FGM interface, wherein the FGM suppressor:

exhibits an additional gradation of at least one additional characteristic from the one side of the FGM suppressor to the another side of the FGM suppressor; and

mitigates leakage of the mechanical energy generated by the transducer to an environment of the user.

12. The cartilage conduction system of claim 11 , wherein the gradation of the characteristic exhibited by the FGM interface and the additional gradation of the characteristic exhibited by the FGM suppressor differ from one another.

13. The cartilage conduction system of claim 11 , wherein the additional gradation of the characteristic exhibited by the FGM suppressor comprises a specific gradient of loss factor from the one side of the FGM suppressor to the another side of the FGM suppressor along one dimension.

14. The cartilage conduction system of claim 1 , wherein the FGM interface is 3D-printed.

15. An artificial reality system comprising:

a head-mounted display; and

a cartilage conduction device communicatively coupled to the head-mounted display, wherein the cartilage conduction device comprises:

a transducer that generates mechanical energy; and

a functionally graded material (FGM) interface dimensioned to be coupled between the transducer and cartilage located on an outer ear of a user, wherein the FGM interface:

exhibits a gradation of at least one characteristic from one side of the FGM interface that is impedance-matched to the transducer to another side of the FGM interface that is impedance-matched to the cartilage located on the outer ear of the user; and

facilitates transferring the mechanical energy across the gradation of the characteristic from the transducer to the cartilage.

16. The artificial reality system of claim 15 , wherein the FGM interface comprises a plurality of discrete material layers that form the gradation of the characteristic exhibited by the FGM interface.

17. The artificial reality system of claim 15 , wherein the gradation of the characteristic exhibited by the FGM interface comprises a specific gradient of the characteristic from the one side to the another side along one dimension of the FGM interface.

18. The artificial reality system of claim 15 , wherein the characteristic comprises at least one of:

stiffness;

loss factor;

density;

lattice spacing;

porosity;

Poisson's ratio; or

filler content.

19. A method comprising:

manufacturing a functionally graded material (FGM) interface that:

exhibits a gradation of at least one characteristic from one side of the FGM interface that is impedance-matched to a transducer that generates mechanical energy to another side of the FGM interface that is impedance-matched to cartilage located on an outer ear of a user; and

is dimensioned to be coupled to the cartilage located on the outer ear of the user; and

coupling the FGM interface to the transducer to enable the FGM interface to facilitate transferring the mechanical energy across the gradation of the characteristic from the transducer to the cartilage.