Variable acoustic grating based on changing acoustic impedances

Patent metadata

Field	Value
Publication number	US-9704473-B2
Application number	US-96579610-A
Country	US
Kind code	B2
Filing date	Dec 10, 2010
Priority date	Dec 10, 2010
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

An embodiment is a variable acoustic grating. Each of the local grating structures in an array of local grating structures has a variable impedance such that the impedance is modified, steering an ultrasonic signal impinging on the array in a reflection or transmission mode through a medium.

First claim

What is claimed is:

1. An apparatus comprising:
an array of local acoustic grating structures, each of the local acoustic grating structures having a variable acoustic impedance such that the acoustic impedance is modified, steering an ultrasonic signal impinging on the array in a transmission mode through a medium, wherein each of the local grating structures comprises a membrane defining a gap or a cavity, the membrane deflecting from an uncollapsed state into the gap or the cavity when an actuation is applied to the membrane.

2. The apparatus of claim 1 further comprising:
a substrate; and
a control layer on the substrate and coupled to the array of the local grating structures, the control layer having a controller that generates the actuation.

3. The apparatus of claim 1 wherein the membrane deflects into the gap or the cavity in a collapsed state when the actuation exceeds a pull-in threshold.

4. The apparatus of claim 1 wherein the membrane is made of metal, plastic, or silicon nitride.

5. The apparatus of claim 1 wherein the substrate is made of glass, quartz, stainless steel, or plastic.

6. The apparatus of claim 2 further comprising:
a transmitter coupled to the substrate to generate the ultrasonic signal, the ultrasonic signal being reflected from the array when the membrane is in the uncollapsed state and transmitted through the medium when the membrane is in the collapsed state.

7. The apparatus of claim 1 wherein the membrane is a single-layer membrane, a multilayer membrane, a patterned membrane, or a bistable membrane.

8. The apparatus of claim 1 wherein the gap or the cavity is filled with gas, liquid, or eutectic material.

9. The apparatus of claim 1 wherein the array is a one-dimensional (1-D) or two-dimensional (2D) array having one of a linear grating, a chirped grating, or a zone/phase plate grating pattern.

10. A system comprising:
a transmitter to generate an ultrasonic signal through a medium; and
an acoustic grating structure coupled to the medium to dynamically steer or focus the ultrasonic signal, the acoustic grating structure comprising:
an array of local acoustic grating structures, each of the local acoustic grating structures having a variable acoustic impedance such that the acoustic impedance is modified steering an ultrasonic signal impinging on the array in a transmission mode through the medium,
wherein each of the grating structures comprises: a membrane defining a gap or a cavity, the membrane deflecting from an uncollapsed state into the gap or the cavity when an actuation is applied to the membrane.

11. The system of claim 10 wherein the grating structure further comprises:
a substrate; and
a control layer on the substrate and coupled to the array of the local grating structures, the control layer having a controller that generates the actuation.

Assignees

• Wong Serena Han Ying
• Lu Jeng Ping
• Apte Raj B
• Palo Alto Res Ct Inc

Inventors

• Wong Serena Han Ying
• Lu Jeng Ping
• Apte Raj B

Classifications

• G02B6/34

  utilising prism or grating {(G02B6/293 takes precedence)} · CPC title

• G10K11/30 Primary

  using refraction, e.g. acoustic lenses · CPC title