MULTI-APERTURE ACOUSTIC HORN

• US 20100109481A1
• Filed: 10/30/2008
• Published: 05/06/2010
• Est. Priority Date: 10/30/2008
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies Limited (Broadcom, Inc.)
• Inventors: BUCCAFUSCA, Osvaldo
• Granted Patent: US 8,199,953 B2
• Time in Patent Office: Days
• US Class Current: 310/335
• CPC Class Codes: G10K 11/025 horns for impedance matching see provisionally also G10K11/28

Abstract

A device, for transmitting or receiving ultrasonic signals, includes a transducer and an acoustic horn. The transducer is configured to convert between electrical energy and the ultrasonic signals, and may be a micro electromechanical system (MEMS) transducer. The acoustic horn is coupled to the transducer, and includes multiple apertures through which the ultrasonic signals are transmitted or received in order to manipulate at least one of a radiation pattern, frequency response or magnitude of the ultrasonic signals. The multiple apertures have different sizes.

Claims

1. A device for transmitting or receiving ultrasonic signals, the device comprising:

a transducer configured to convert between electrical energy and the ultrasonic signals; and

an acoustic horn coupled to the transducer, the acoustic horn comprising a plurality of apertures through which the ultrasonic signals are transmitted or received in order to manipulate at least one of a radiation pattern, frequency response or magnitude of the ultrasonic signals,

wherein the plurality of apertures comprise a corresponding plurality of different aperture sizes.

2. The device of claim 1, wherein the transducer comprises a micro electro-mechanical system (MEMS) transducer.

3. The device of claim 1, wherein the acoustic horn comprises a plurality of horn structures having a common throat opening adjacent to the transducer and a plurality of mouth openings corresponding to the plurality of apertures.

4. The device of claim 3, wherein the plurality of horn structures comprise a center horn structure and at least two adjacent peripheral horn structures aligned in a linear form.

5. The device of claim 3, wherein the plurality of apertures are aligned in a two-dimensional form.

6. The device of claim 4, wherein the center horn structure has a different length than the at least two adjacent peripheral horn structures to manipulate relative phases of the ultrasonic signals respectively emitted from the corresponding plurality of apertures.

7. The device of claim 4, wherein a radiation pattern of the ultrasonic signals transmitted from the device comprise two or more lobes extending at different angles from the transducer.

8. The device of claims 4, wherein a radiation pattern of the ultrasonic signals transmitted from the device comprises one lobe at a non-zero angle from the transducer.

9. The device of claim 1, wherein the acoustic horn comprises an acoustic lens fixed to a mouth opening of the acoustic horn, the lens defining a pattern comprising the plurality of apertures.

10. The device of claim 9, wherein the plurality of apertures comprise a plurality of concentric circles.

11. The device of claim 9, wherein the pattern comprises a Fresnel pattern.

12. The device of claim 11, wherein the plurality of concentric circles define alternating zones in which portions of the ultrasonic signals are blocked.

13. The device of claim 12, wherein boundaries of the alternating zones are approximated by the following formula, in which R_n is a radius of boundary n, λ

is transducer and a focal point of the lens, respectively;

$R_n=\sqrt{n<br><br><br><br>\mathrm{\lambda <br><br>}<br><br>\left(\frac{z_1<br><br>z_2}{z_1+z_{21}}\right)}$

14. A device for transmitting ultrasonic signals, the device comprising:

a micro electromechanical system (MEMS) transducer configured to convert electrical energy into acoustic signals; and

an acoustic horn coupled to the transducer for amplifying the ultrasonic signals, the acoustic horn comprising a plurality of horn structures having a common throat opening for receiving the ultrasonic signals from the transducer, the plurality of horn structures comprising a center horn structure and a plurality of peripheral horn structures,

wherein dimensions of at least two of the plurality of horn structures being different.

15. The device of claim 14, wherein at least one of the plurality of horn structures comprises a tubular inner portion and a conical outer portion.

16. The device of claim 15, wherein the center horn structure creates a delay of about a half wavelength of a portion of the ultrasonic signals transmitted through each of the plurality of peripheral horn structures.

17. The device of claim 14, wherein a center point of the mouth aperture of the center horn structure is the same distance from a center point of mouth apertures of each of the plurality of peripheral horn structures.

18. A device for transmitting ultrasonic signals, the device comprising:

a micro electromechanical system (MEMS) transducer configured to convert electrical energy to the ultrasonic signals;

an acoustic horn coupled to the transducer for amplifying the ultrasonic signals, the acoustic horn comprising a throat portion adjacent to the MEMS transducer for receiving the ultrasonic signals and mouth portion larger in area than the throat portion; and

an acoustic lens structure attached to the mouth portion of the acoustic horn, the lens structure defining a predetermined pattern of openings, through which the ultrasonic signals are transmitted, for manipulating a radiation pattern of the ultrasonic signals.

19. The device of claim 18, wherein the predetermined pattern comprises a Fresnel pattern.

20. The device of claim 19, further comprising:

a pressure chamber configured to connect the MEMS transducer and the input portion of the acoustic horn.