# US 10,307,792 B2 · Ultrasonic transducer, ultrasonic finger recognition sensor and electronic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,307,792 B2 - Document ID: US10307792B2 - Status: Granted - Kind: B2 - Application number: 15/491,041 - Filed: 2017-04-19 - Published: 2018-03-08 - Granted: 2019-06-04 - Earliest claimed: 2016-09-05 - Assignees: Nanchang O-Film Bio-Identification Technology Co., Ltd. - Applicants: Nanchang O-Film Bio-Identification Technology Co., Ltd. - Inventors: Anpeng Bai; Wensi Sun - Web page: https://patentgrep.com/patent/US10307792B2 ## CPC - B06B 1/0629: {Square array} - G06V 40/1306: {non-optical, e.g. ultrasonic or capacitive sensing} - H10N 30/092: Forming composite materials - H10N 30/101: {with electrical and mechanical input and output, e.g. having combined actuator and sensor parts} - H10N 30/852: {Composite materials, e.g. having 1-3 or 2-2 type connectivity} - B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R) - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract The present disclosure discloses an ultrasonic transducer. The ultrasonic transducer includes an active layer. The active layer includes an array of piezoelectric pillars configured for emitting and receiving ultrasound and an attenuation portion surrounding sidewalls of the piezoelectric pillars and configured for attenuating a part of the ultrasound emitted from the sidewalls of the piezoelectric pillars. The present disclosure also relates to an ultrasonic fingerprint recognition sensor and an electronic device having the ultrasonic transducer. ## Claims ### Claim 1 An ultrasonic transducer comprising: an active layer comprising: an array of piezoelectric pillars configured for emitting and receiving ultrasound; and an attenuation portion surrounding sidewalls of the piezoelectric pillars and configured for attenuating a part of the ultrasound emitted from the sidewalls of the piezoelectric pillars; wherein the attenuation portion is made of a material with an acoustic impedance substantially lower than about 4.53 M Rayls. ### Claim 2 (depends on 1) The ultrasonic transducer of claim 1, wherein the piezoelectric pillars are made of piezoelectric material selected from the group consisting of: monocrystalline ceramics, polycrystalline ceramics, polymers, and compound thereof. ### Claim 3 (depends on 1) The ultrasonic transducer of claim 1, wherein the piezoelectric pillars are made of lead zirconate titanate piezoelectric ceramics. ### Claim 4 (depends on 1) The ultrasonic transducer of claim 1, wherein each of the piezoelectric pillars is a rectangular pillar. ### Claim 5 (depends on 1) The ultrasonic transducer of claim 1, wherein the piezoelectric pillars runs through the active layer substantially along a height direction of the active layer. ### Claim 6 (depends on 1) The ultrasonic transducer of claim 1, wherein the attenuation portion is made of silica gel. ### Claim 7 (depends on 1) The ultrasonic transducer of claim 1, wherein the attenuation portion is integrally formed by filling a material of the attenuation portion among the piezoelectric pillars. ### Claim 8 (depends on 1) The ultrasonic transducer of claim 1, wherein the attenuation portion is integrally formed by cutting a layer of the material of the attenuation portion to form an array of holes for receiving the piezoelectric pillars respectively. ### Claim 9 (depends on 1) The ultrasonic transducer of claim 1, wherein the attenuation portion is in contact with the piezoelectric pillars. ### Claim 10 (depends on 1) The ultrasonic transducer of claim 1, wherein the attenuation portion is spaced away from the piezoelectric pillars. ### Claim 11 (depends on 10) The ultrasonic transducer of claim 10, wherein gaps formed between the attenuation portion and the piezoelectric pillars are of constant uniform width. ### Claim 12 (depends on 1) The ultrasonic transducer of claim 1, wherein the attenuation portion comprises a first portion surrounding the piezoelectric pillars and a second portion surrounding the first portion. ### Claim 13 (depends on 12) The ultrasonic transducer of claim 12, wherein the second portions are of constant uniform width. ### Claim 14 (depends on 12) The ultrasonic transducer of claim 12, wherein at least one of the first portion and the second portion is made of a material with an acoustic impedance substantially lower than about 4.53 M Rayls. ### Claim 15 (depends on 1) The ultrasonic transducer of claim 1, wherein the piezoelectric pillars run through the active layer along a height direction of the active layer, the ultrasonic transducer further comprises a plurality of receiving electrode lines formed on the active layer and each of the receiving electrode lines is connected to a column of the piezoelectric pillar, and a plurality of emitting electrode lines formed on the active layer and each of the emitting electrode lines is connected to a column of the piezoelectric pillars. ### Claim 16 (depends on 15) The ultrasonic transducer of claim 15, wherein the ultrasonic transducer further comprises a top protective layer formed on the upper surface that covers the active layer 12 and the receiving electrode lines, and a bottom protective layer formed on the lower surface and covers the active layer and the emitting electrode lines. ### Claim 17 (depends on 16) The ultrasonic transducer of claim 16, wherein an acoustic resistance of the top protective layer is substantially greater than an acoustic resistance of the attenuation portion. ### Claim 18 (depends on 16) The ultrasonic transducer of claim 16, wherein an acoustic resistance of the low protective layer is substantially greater than an acoustic resistance of the top protective layer 18n. ### Claim 19 (depends on 1) An ultrasonic fingerprint recognition device, comprising: a substrate; a control chip positioned on and electrically connected to the substrate; the ultrasonic transducer of claim 1, positioned on and electrically connected to the control chip; and a package packing the substrate, the control chip, and the ultrasonic transducer as a module. ### Claim 20 (depends on 19) An electronic device comprising: a casing; and the ultrasonic fingerprint recognition device of claim 19 positioned in the casing for fingerprint recognition or authorization.