# US 10,503,309 B2 · Drive scheme for ultrasonic transducer pixel readout > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,503,309 B2 - Document ID: US10503309B2 - Status: Granted - Kind: B2 - Application number: 15/474,084 - Filed: 2017-03-30 - Published: 2017-10-05 - Granted: 2019-12-10 - Earliest claimed: 2016-04-04 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Ashish Hinger - Web page: https://patentgrep.com/patent/US10503309B2 ## CPC - G06F 3/0416: {Control or interface arrangements specially adapted for digitisers} - A61B 5/1172: using fingerprinting - B06B 1/0622: {on one surface} - G01N 29/2437: {Piezoelectric probes} - G01N 29/26: Arrangements for orientation or scanning {by relative movement of the head and the sensor (mechanical steering of sound transducers or their beams G10K11/35)} - G06F 3/043: using propagating acoustic waves - G06V 40/1306: {non-optical, e.g. ultrasonic or capacitive sensing} - H03K 17/74: by the use, as active elements, of diodes (by the use of more than one type of semiconductor device H03K17/567; by the use of tunnel diodes H03K17/58; by the use of negative resistance diodes H03K17/70) - H04R 17/005: {using a piezoelectric polymer} - G01H 1/00: Measuring {characteristics of} vibrations in solids by using direct conduction to the detector (G01H9/00, G01H11/00 take precedence) - G06F 3/03547: {Touch pads, in which fingers can move on a surface} - G06F 2203/0338: Fingerprint track pad, i.e. fingerprint sensor used as pointing device tracking the fingertip image - H04R 17/10: Resonant transducers, i.e. adapted to produce maximum output at a predetermined frequency - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - 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) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES ## Abstract This disclosure provides some implementations of systems, methods and apparatus associated with a drive scheme for ultrasonic transducer pixel readout. In some implementations, a piezoelectric ultrasonic transducer has a first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes. The second electrode is coupled with a sampling node. A sampling diode has an input and an output. The input is coupled to receive a diode bias signal. The output is coupled with the sampling node. Controller circuitry is configured to control the diode bias signal to at least partially drive a voltage at the sampling node. Read circuitry is coupled with the sampling node to read the voltage. ## Claims ### Claim 1 An apparatus comprising: a piezoelectric ultrasonic transducer having a first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes, the second electrode being coupled with a sampling node, wherein the first electrode is configured to receive a receive bias signal; a sampling diode having an input and an output, the input coupled to receive a diode bias signal, the output coupled with the sampling node; controller circuitry configured to control the diode bias signal to at least partially drive a voltage at the sampling node; and read circuitry coupled with the sampling node to read the voltage, wherein the controller circuitry is configured to control the diode bias signal to switch between two voltage levels comprising a first level and a second level, the first level being a non-zero voltage level that corresponds to a normal mode of operation of the read circuitry and the second level being a non-zero voltage level that corresponds to a sampling mode of operation of the read circuitry, and wherein the first level is different from the second level and from a voltage level of the receive bias signal, and wherein the second level is different from the first level and from the voltage level of the receive bias signal. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the controller circuitry is configured to assert the second level during a sampling window corresponding to activation of the read circuitry. ### Claim 3 (depends on 1) The apparatus of claim 1, further comprising a substrate disposed adjacent to the second electrode opposite the piezoelectric layer, the substrate being a thin-film transistor (TFT) layer and comprising the sampling diode. ### Claim 4 (depends on 3) The apparatus of claim 3, further comprising a reset transistor formed in the TFT layer and coupled with the sampling diode to control resetting of the voltage. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the first electrode is coupled with one of: a ground terminal, a DC voltage source or a fixed AC voltage source. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the first electrode is floating. ### Claim 7 (depends on 1) The apparatus of claim 1, further comprising a touch controller coupled with the first electrode, the touch controller configured to provide touch control of the piezoelectric layer. ### Claim 8 (depends on 1) The apparatus of claim 1, further comprising a platen disposed adjacent to the first electrode opposite the piezoelectric layer. ### Claim 9 A method comprising: providing a diode bias signal to a sampling diode coupled with a sampling node; providing a receive bias signal to a first electrode; initiating transmission of an ultrasonic signal using a piezoelectric ultrasonic transducer having the first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes, the second electrode being coupled with the sampling node, the piezoelectric ultrasonic transducer capable of receiving a reflected portion of the ultrasonic signal and generating a response characteristic based on the reflected portion of the ultrasonic signal; controlling the diode bias signal to bias the diode in association with a temporary transition of a mode of operation from a normal mode to a sampling mode, the diode bias signal being driven to a first level corresponding to the normal mode and a second level corresponding to the sampling mode, wherein the first level is a non-zero voltage level that is different from the second level and from a voltage level of the receive bias signal, and wherein the second level is a non-zero voltage level that is different from the first level and from the voltage level of the receive bias signal; and enabling sampling, during the sampling mode of operation, of an electrical signal at the sampling node. ### Claim 10 (depends on 9) The method of claim 9, wherein read circuitry is controlled to perform the sampling during the sampling mode of operation. ### Claim 11 (depends on 9) The method of claim 9, further comprising: resetting a voltage at the sampling node using a reset switch coupled with the diode. ### Claim 12 (depends on 9) The method of claim 9, wherein a substrate is disposed adjacent to the second electrode opposite the piezoelectric layer, the substrate being a thin-film transistor (TFT) layer and comprising the sampling diode. ### Claim 13 A non-transitory computer readable medium storing program code to be executed by one or more processors, the program code comprising instructions configured to cause: providing a diode bias signal to a sampling diode coupled with a sampling node; providing a receive bias signal to a first electrode; initiating transmission of an ultrasonic signal using a piezoelectric ultrasonic transducer having the first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes, the second electrode being coupled with the sampling node, the piezoelectric ultrasonic transducer capable of receiving a reflected portion of the ultrasonic signal and generating a response characteristic based on the reflected portion of the ultrasonic signal; controlling the diode bias signal to bias the diode in association with a temporary transition of a mode of operation from a normal mode to a sampling mode, the diode bias signal being driven to a first level corresponding to the normal mode and a second level corresponding to the sampling mode, wherein the first level is a non-zero voltage level that is different from the second level and from a voltage level of the receive bias signal, and wherein the second level is a non-zero voltage level that is different from the first level and from the voltage level of the receive bias signal; and enabling sampling, during the sampling mode of operation, of an electrical signal at the sampling node. ### Claim 14 (depends on 13) The computer readable medium of claim 13, the instructions further configured to cause: resetting a voltage at the sampling node using a reset switch coupled to the diode. ### Claim 15 An apparatus comprising: transducer means for generating an ultrasonic wave and receiving a reflected portion of the wave, the transducer means having a first electrode, a second electrode, and a piezoelectric layer disposed between the first and second electrodes, the first electrode configured to receive a receive bias signal, the second electrode being coupled with a sampling node; diode bias means for at least partially driving an electrical signal at the sampling node, the diode bias means coupled with the sampling node, the diode bias means providing a diode bias signal to a sampling diode at a first level corresponding to a normal mode of operation and a second level corresponding to a sampling mode of operation, wherein the first level is a non-zero voltage level that is different from the second level and from a voltage level of the receive bias signal, and wherein the second level is a non-zero voltage level that is different from the first level and from the voltage level of the receive bias signal; and reading means for reading the electrical signal, the reading means coupled with the sampling node.