Hidden ultrasonic sensor assembly

1. An ultrasonic sensor assembly configured to be placed against an inside surface of a panel for sensing objects on an opposite side of the panel, the ultrasonic sensor assembly comprising:

an ultrasonic sensor;

a preload structure having the ultrasonic sensor attached thereto, the preload structure configured for applying a preload on the ultrasonic sensor toward the inside surface;

a coupling element that interfaces between the ultrasonic sensor and the inside surface of the panel; and

a damping material placed against the inside surface and not where the coupling element interfaces between the ultrasonic sensor and the inside surface; and

an acoustic foam placed in contact with the damping material, the acoustic foam configured for absorbing airborne acoustic waves.

2. The ultrasonic sensor assembly of claim 1 , wherein the acoustic foam is placed on top of the damping material.

3. The ultrasonic sensor assembly of claim 2 , wherein the damping material has an opening in which the coupling element interfaces between the ultrasonic sensor and the inside surface, wherein the opening is larger than the coupling element forming an area of the inside surface between the coupling element and the damping material, and wherein the acoustic foam is positioned so as to substantially cover the area of the inside surface between the coupling element and the damping material.

4. The ultrasonic sensor assembly of claim 1 , the coupling element comprises a matrix material that is reinforced with a filler.

5. The ultrasonic sensor assembly of claim 4 , wherein the matrix material comprises an elastomer or a viscoelastic material.

6. The ultrasonic sensor assembly of claim 5 , wherein the matrix material comprises Silicone.

7. The ultrasonic sensor assembly of claim 4 , wherein the filler comprises a mesh.

8. The ultrasonic sensor assembly of claim 4 , wherein the filler comprises fiberglass.

9. The ultrasonic sensor assembly of claim 1 , wherein the panel is part of a door on a vehicle.

10. The ultrasonic sensor assembly of claim 9 , wherein the door is a dual hinge door configured for opening and closing substantially in a vertical direction.

11. The ultrasonic sensor assembly of claim 1 , wherein the preload structure is configured for being attached to the inside surface.

12. A method comprising:

generating ultrasonic waves through a panel by an ultrasonic sensor, the ultrasonic sensor having a coupling element that interfaces between the ultrasonic sensor and an inside surface of the panel, the coupling element comprising a matrix material that is reinforced with a filler;

damping acoustic waves in the panel using a damping material placed against the inside surface and not where the coupling element interfaces between the ultrasonic sensor and the inside surface;

absorbing airborne acoustic waves using an acoustic foam, wherein the damping material has an opening in which the coupling element interfaces between the ultrasonic sensor and the inside surface, wherein the opening is larger than the coupling element forming an area of the inside surface between the coupling element and the damping material, and wherein the acoustic foam is positioned so as to substantially cover the area of the inside surface between the coupling element and the damping material; and

receiving an echo return wave through the panel using the ultrasonic sensor.

13. The method of claim 12 , wherein the acoustic foam is placed on top of the damping material.

14. The method of claim 12 , wherein the matrix material comprises an elastomer or a viscoelastic material.

15. The method of claim 12 , wherein the matrix material comprises Silicone.

16. The method of claim 12 , wherein the filler comprises one or more of a mesh or fiberglass.