Layer for inducing varying delays in ultrasonic signals propagating in ultrasonic sensor

Patent metadata

Field	Value
Publication number	US-11086453-B2
Application number	US-201715827529-A
Country	US
Kind code	B2
Filing date	Nov 30, 2017
Priority date	Sep 29, 2017
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

An apparatus includes an ultrasonic transmitter, an ultrasonic receiver, and an acoustic delay gradient layer disposed in an acoustic path between the ultrasonic transmitter and the ultrasonic receiver. The acoustic delay gradient layer is configured to cause a reflection from a platen interface of the transmitted ultrasonic signal to reach the first receiver region at a first time and the reflection from the platen interface of the transmitted ultrasonic signal to reach the second receiver region at a second time that is different from the first time. The apparatus can further include a controller configured to set for a first region or portion of the receiver, a first range gate window (RGW). The controller is also configured to set, for a second region or portion of the receiver, a second RGW, and to establish a first temporal delay between the first RGW and the second RGW.

First claim

What is claimed is:

1. An apparatus comprising:
an ultrasonic transmitter configured to transmit an ultrasonic signal towards a platen interface;
an ultrasonic receiver comprising a plurality of receiver regions within the ultrasonic receiver, the plurality of receiver regions including at least a first receiver region and a second receiver region, the ultrasonic receiver configured to receive a reflection of the transmitted ultrasonic signal from the platen interface; and
an acoustic delay gradient layer disposed in an acoustic path between the ultrasonic transmitter and the ultrasonic receiver, the acoustic delay gradient layer configured to cause the reflection from the platen interface of the transmitted ultrasonic signal to reach the first receiver region at a first time and the reflection from the platen interface of the transmitted ultrasonic signal to reach the second receiver region at a second time that is different from the first time.

2. The apparatus of claim 1 , wherein the acoustic delay gradient layer comprises a tapered layer having a taper angle, the taper angle of the tapered layer causing the reflection from the platen interface to reach the first receiver region after propagating over a first physical distance and the tapered layer causing the reflection from the platen interface to reach the second receiver region after propagating over a second physical distance different from the first physical distance.

3. The apparatus of claim 2 , wherein the taper angle is less than a ten degree angle.

4. The apparatus of claim 1 , wherein the acoustic delay gradient layer comprises a first acoustic delay gradient layer region corresponding to the first receiver region and a second acoustic delay gradient layer region corresponding to the second receiver region and wherein a first speed of sound propagating in the first acoustic delay gradient layer region and a second speed of sound propagating in the second acoustic delay gradient layer region are different.

5. The apparatus of claim 4 , wherein the acoustic delay gradient layer comprises a first material in the first acoustic delay gradient layer region and a second material in the second acoustic delay gradient layer region.

6. The apparatus of claim 4 , wherein the acoustic delay gradient layer comprises a glass layer and the glass layer in the first acoustic delay gradient layer region has a doping that is different from a doping of the glass layer in the second acoustic delay gradient layer region.

7. The apparatus of claim 1 , wherein the acoustic delay gradient layer is disposed between the ultrasonic transmitter and the ultrasonic receiver.

8. The apparatus of claim 1 , wherein the receiver is closer to the platen interface than the ultrasonic transmitter.

9. The apparatus of claim 1 , wherein the ultrasonic transmitter is a non-segmented transmitter configured to transmit the ultrasonic signal towards the platen interface across an entirety of the non-segmented transmitter simultaneously.

10. The apparatus of claim 1 , further comprising a controller configured to enable the first receiver region to measure the reflection of the transmitted ultrasonic signal during a first window beginning at a first window begin time and to enable the second receiver region to measure the reflection of the transmitted ultrasonic signal during a second window beginning at a second window begin time different from the first window begin time.

11. The apparatus of claim 10 , wherein
the controller configured to enable the first receiver region to measure the reflection of the transmitted ultrasonic signal during a first window beginning at the first window begin time comprises the controller configured to control an application of a sample voltage to a receiver bias electrode corresponding to the first receiver region during a first range gate window beginning at the first window begin time, and
the controller configured to enable the second receiver region to measure the reflection of the transmitted ultrasonic signal during a second window beginning at the second window begin time comprises the controller configured to control the application of the sample voltage to a receiver bias electrode corresponding to the second receiver region during a second range gate window beginning at the second window begin time.

12. The apparatus of claim 1 , wherein the apparatus is disposed within a mobile device.

13. A method for operating an ultrasonic sensor, the method comprising:
transmitting, by an ultrasonic transmitter of the ultrasonic sensor, an ultrasonic signal toward a platen interface of the ultrasonic sensor along an acoustic path that includes an acoustic delay gradient layer;
receiving a reflection of the transmitted ultrasonic signal reflected from the platen interface at a first receiver region of an ultrasonic receiver of the ultrasonic sensor at a first time; and
receiving the reflection of the transmitted ultrasonic signal reflected from the platen interface at a second receiver region of the ultrasonic receiver at a second time different from the first time.

14. The method of claim 13 , wherein the transmitting the ultrasonic signal towards the platen interface comprises transmitting the ultrasonic signal through a tapered acoustic delay gradient layer having a taper angle, the taper angle causing the reflection from the platen interface to reach the first receiver region after propagating over a first physical distance and the tapered angle causing the reflection from the platen interface to reach the second receiver region after propagating over a second physical distance different from the first physical distance.

15. The method of claim 13 , wherein the transmitting the ultrasonic signal toward the platen interface comprises transmitting the ultrasonic signal through a first acoustic delay gradient layer region corresponding to the first receiver region at a first speed of sound and transmitting the ultrasonic signal through a second acoustic delay gradient layer region corresponding to the second receiver region at a second speed of sound different from the first speed of sound.

16. The method of claim 13 , wherein the transmitting the ultrasonic signal toward the platen interface comprises transmitting the ultrasonic signal through the acoustic delay gradient layer disposed between the ultrasonic transmitter and the ultrasonic receiver.

17. The method of claim 13 , wherein the transmitting the ultrasonic signal toward the platen interface comprises transmitting the ultrasonic transmitter using a non-segmented transmitter configured to transmit the ultrasonic signal towards the platen interface across an entirety of the non-segmented transmitter simultaneously.

18. The method of claim 13 , wherein
the receiving the reflection of the transmitted ultrasonic signal at the first receiver region at the first time comprises enabling the first receiver region to measure the reflection of the transmitted ultrasonic signal during a first window beginning at a first window begin time; and
the receiving the reflection of the transmitted ultrasonic signal at the second receiver region at the second time comprises enabling the second receiver region to measure the reflection of the transmitted ultrasonic signal during a second window beginning at a second window begin time different from the first window begin time.

19. The method of claim 18 , wherein
enabling the first receiver region to measure the reflection of the transmitted ultrasonic signal during the first window beginning at t

Assignees

• Qualcomm Inc

Inventors

• Miranto James Anthony
• Kitchens Jack Conway
• Gojevic Stephen Michael
• Campbell Todd
• Potter Stephen James
• Pezanoski Steven

Classifications

• G06V40/1306

  non-optical, e.g. ultrasonic or capacitive sensing · CPC title

• G01H11/08

  using piezoelectric devices · CPC title

• G06F3/0436 Primary

  in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate · CPC title

• G06F1/169

  the I/O peripheral being an integrated pointing device, e.g. trackball in the palm rest area, mini-joystick integrated between keyboard keys, touch pads or touch stripes (G06F1/1643 takes precedence; constructional details of pointing devices G06F3/033) · CPC title

• B06B2201/56

  Foil type, e.g. PVDF · CPC title