Ultrasound sensor with resonance frequency adjustment portion

Patent metadata

Field	Value
Publication number	US-10488370-B2
Application number	US-201515323662-A
Country	US
Kind code	B2
Filing date	Jul 6, 2015
Priority date	Jul 4, 2014
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

An ultrasound sensor includes a substrate having an opening portion, a diaphragm that blocks the opening portion, and an ultrasound element including a first electrode, a piezoelectric layer, and a second electrode that is laminated on the substrate. The first electrode, piezoelectric layer, and the second electrode are laminated onto the substrate on a side opposite of the opening portion of the diaphragm and overlap to form an active portion. A movable portion of the diaphragm is oscillatable by the active portion and a resonance frequency adjustment portion for adjusting a resonance frequency of the movable portion is provided on a lateral side of the active portion opposing the movable portion.

First claim

The invention claimed is:

1. An ultrasound sensor, comprising:
a substrate on which an opening portion is formed;
a diaphragm which is provided on the substrate so as to block the opening portion; and
ultrasound elements which include a first electrode, a piezoelectric layer and a second electrode and which are laminated on an opposite side to the opening portion of the diaphragm, wherein
when a direction in which the first electrode, the piezoelectric layer and the second electrode are laminated is referred to as a Z-direction, a portion in which the first electrode, the piezoelectric layer and the second electrode are overlapped in the Z-direction is referred to as an active portion, and a portion which is a range to the extent that the diaphragm is oscillatable by driving the active portion is referred to as a movable portion,
the active portion is arranged opposite to the movable portion;
the active portion has a smaller profile than that of the movable portion in a plan view; and
a resonance frequency adjustment portion for adjusting a resonance frequency is provided on a lateral side of the active portion, at least in a region opposite to the movable portion such that a majority of the resonance frequency adjustment portion is located outside of the movable portion in the plan view,
wherein the resonance frequency adjustment portion includes a length that extends in a y-direction and a width that extends in an x-direction, the width overlaps an edge of the opening portion that extends in the y-direction, and the length of the resonance frequency adjustment portion is less than a length of the edge of the opening portion that extends in the y-direction.

2. The ultrasound sensor according to claim 1 ,
wherein, in plan view, the active portion is in a rectangle shape, and
the resonance frequency adjustment portion is provided on a lateral side of a long side of the rectangle shape.

3. The ultrasound sensor according to claim 1 ,
wherein a plurality of the movable portions and the active portions are arranged in at least one of the X-direction and Y-direction.

4. The ultrasound sensor according to claim 3 ,
wherein the resonance frequency adjustment portions are provided on lateral sides of a portion of the plurality of the active portions, while the resonance frequency adjustment portions are not provided on lateral sides of other portion of the plurality of the active portions.

5. The ultrasound sensor according to claim 3 , wherein two or more types of the active portions are provided, each of which has the piezoelectric layer having a different width such that the width is a length of any one of the sides in the X-direction or the Y-direction in a case where the active portion is in a square shape and the width is a length of a short side in a case where the active portion is in a rectangle shape, in plan view.

6. The ultrasound sensor according to claim 3 , wherein two or more types of the active portions are provided, each of which has the piezoelectric layer having a different thickness.

7. The ultrasound sensor according to claim 3 , wherein the plurality of ultrasound elements include the ultrasound element set as a dedicated reception type and the ultrasound element set as a dedicated transmission type.

8. The ultrasound sensor according to claim 1 , wherein the resonance frequency adjustment portion is composed of a material different from those of the first electrode, the piezoelectric layer and the second electrode.

9. The ultrasound sensor according to claim 1 , wherein the second electrode extends continuously along a surface of the diaphragm facing away from the substrate.

10. The ultrasound sensor according to claim 9 , wherein the resonance frequency adjustment portion is positioned on an exposed surface of the second electrode.

11. The ultrasound sensor according to claim 9 , wherein the piezoelectric layer comprises manganese (Mn).

Assignees

• Seiko Epson Corp

Inventors

• Kojima Chikara

Classifications

• G01N29/2437

  Piezoelectric probes · CPC title

• G01N29/34 Primary

  Generating the ultrasonic, sonic or infrasonic waves {, e.g. electronic circuits specially adapted therefor} · CPC title

• B06B1/0629

  Square array · CPC title

• G01N29/12

  by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)} · CPC title

• G01N2291/014

  Resonance or resonant frequency · CPC title