# US 2021/0242393 A1 · System including piezoelectric capacitor assembly having force-measuring, touch-sensing, and haptic functionalities

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- Number: US 2021/0242393 A1
- Document ID: US20210242393A1
- Status: Published application
- Kind: A1
- Application number: 17/161,591
- Filed: 2021-01-28
- Published: 2021-08-05
- Earliest claimed: 2020-01-30
- Assignees: UltraSense Systems, Inc.
- Applicants: UltraSense Systems, Inc.
- Inventors: Hao-Yen Tang; Sina Akhbari; Mo Maghsoudnia
- Web page: https://patentgrep.com/patent/US20210242393A1

## CPC

- G01L 1/146: {for measuring force distributions, e.g. using force arrays (G01L1/148 takes precedence)}
- H10N 30/40: with electrical input and electrical output, e.g. functioning as transformers
- G01L 1/148: {using semiconductive material, e.g. silicon}
- G01L 1/16: using properties of piezoelectric devices
- G06F 3/016: {Input arrangements with force or tactile feedback as computer generated output to the user}
- G06F 3/04144: {using an array of force sensing means (position sensing using the local deformation of sensor cells G06F3/0447)}
- G06F 3/044: by capacitive means
- H03K 17/962: {Capacitive touch switches}
- H03K 17/964: {Piezoelectric touch switches}
- H04R 17/00: Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00})
- H10N 30/302: {Sensors}
- H10N 30/8542: {Alkali metal based oxides, e.g. lithium, sodium or potassium niobates}
- H10N 30/87: Electrodes or interconnections, e.g. leads or terminals
- H03K 2217/96023: Details of electro-mechanic connections between different elements, e.g.: sensing plate and integrated circuit containing electronics
- H03K 2217/96062: with tactile or haptic feedback
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- 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)

## Abstract

A system includes a piezoelectric capacitor assembly and signal processing circuitry coupled to the piezoelectric capacitor assembly. The piezoelectric capacitor assembly includes a piezoelectric member and piezoelectric capacitors located at respective lateral positions along the piezoelectric member. Each piezoelectric capacitor includes: (1) a respective portion of the piezoelectric member, (2) a first electrode, and (3) a second electrode. The first and second electrodes are positioned on opposite side of the piezoelectric member. The piezoelectric capacitors include piezoelectric force-measuring elements (PFEs). The PFEs are configured to output voltage signals between the respective first electrode and the respective second electrode in accordance with a time-varying strain at the respective portion of the piezoelectric member between the respective first electrode and the respective second electrode resulting from a low-frequency mechanical deformation. The signal processing circuitry is configured to read at least some of the PFE voltage signals.

## Claims

### Claim 1

A system, comprising:
a piezoelectric capacitor assembly comprising:
a piezoelectric member; and
a plurality of piezoelectric capacitors located at respective lateral positions along the piezoelectric member, each of the piezoelectric capacitors comprising: (1) a respective portion of the piezoelectric member, (2) a first electrode, and (3) a second electrode, the first electrode and the second electrode being positioned on opposite sides of the piezoelectric member at the respective portion of the piezoelectric member; and
a signal processing circuitry coupled to the piezoelectric capacitor assembly;
wherein the piezoelectric capacitors comprise a plurality of piezoelectric force-measuring elements (PFEs), configured to output voltage signals between the respective first electrode and the respective second electrode (PFE voltage signals) in accordance with a time-varying strain at the respective portion of the piezoelectric member between the respective first electrode and the respective second electrode resulting from a low-frequency mechanical deformation; and
the signal processing circuitry is configured to read at least some of the PFE voltage signals.

### Claim 2 (depends on 1)

The system of claim 1, wherein the low-frequency mechanical deformation is induced by an excitation having a repetition rate of 100 Hz or less.

### Claim 3 (depends on 2)

The system of claim 2, wherein the repetition rate is 10 Hz or less.

### Claim 4 (depends on 1)

The system of claim 1, wherein the low-frequency mechanical deformation is induced by one or more of the following: touching, pressing, bending, twisting, typing, tapping, and pinching.

### Claim 5 (depends on 1)

The system of claim 1, wherein the low-frequency mechanical deformation comprises a deformation of an entirety of the piezoelectric capacitor assembly.

### Claim 6 (depends on 1)

The system of claim 1, wherein the low-frequency mechanical deformation comprises a compression and expansion of the piezoelectric member along a normal direction approximately normal to the piezoelectric member.

### Claim 7 (depends on 1)

The system of claim 1, wherein the low-frequency mechanical deformation comprises elastic wave oscillations.

### Claim 8 (depends on 1)

The system of claim 1, wherein the low-frequency mechanical deformation comprises expansion and/or compression of the piezoelectric member along a lateral direction approximately parallel to the piezoelectric member.

### Claim 9 (depends on 1)

The system of claim 1, wherein the signal processing circuitry comprises amplifier circuitry for amplifying PFE voltage signals and analog-to-digital converter circuitry for converting amplified PFE voltage signals to PFE digital data.

### Claim 10 (depends on 1)

The system of claim 1, wherein the piezoelectric capacitor assembly additionally comprises a mechanical layer coupled to the piezoelectric member.

### Claim 11 (depends on 10)

The system of claim 10, wherein the mechanical layer comprises silicon, silicon oxide, silicon nitride, aluminum nitride, or a material that is included in the piezoelectric member.

### Claim 12 (depends on 1)

The system of claim 1, wherein the piezoelectric member comprises aluminum nitride, scandium-doped aluminum nitride, polyvinylidene fluoride (PVDF), lead zirconate titanate (PZT), KxNa1−xNbO3 (KNN), quartz, zinc oxide, lithium niobate, or Bi0.5Na0.5TiO3 (BNT).

### Claim 13 (depends on 1)

The system of claim 1, wherein the piezoelectric member is a piezoelectric film.

### Claim 14 (depends on 13)

The system of claim 13, wherein the piezoelectric film comprises lead zirconate titanate (PZT).

### Claim 15 (depends on 1)

The system of claim 1, wherein at least a portion of the signal processing circuitry is an integrated circuit.

### Claim 16 (depends on 1)

The system of claim 1, additionally comprising a cover layer comprising an outer surface which can be touched by a digit and an inner surface opposite the outer surface, wherein the piezoelectric capacitor assembly is coupled to the inner surface, the piezoelectric capacitor assembly being oriented such that the piezoelectric member faces toward the cover layer.

### Claim 17 (depends on 16)

The system of claim 16, wherein the piezoelectric capacitor assembly is oriented such that the piezoelectric member and the cover layer are approximately parallel.

### Claim 18 (depends on 16)

The system of claim 16, wherein the cover layer comprises a material selected from the following: wood, glass, metal, plastic, leather, fabric, and ceramic.

### Claim 19 (depends on 1)

The system of claim 1, wherein:
the piezoelectric capacitors comprise one or more piezoelectric ultrasonic transducers (PUTs), each of the PUTs being configured as a transmitter (PUT transmitter) and/or a receiver (PUT receiver), there being at least one PUT transmitter and at least one PUT receiver;
for at least one of the PUT transmitters (first PUT transmitter(s)), the signal processing circuitry is configured to generate first transmitter voltage signals that are applied between the respective first electrode and the respective second electrode of the respective first PUT transmitter, upon which the respective first PUT transmitter transmits ultrasound signals of a first frequency F1, in longitudinal mode(s) propagating along a normal direction approximately normal to the piezoelectric member towards a sense region;
at least one of the PUT receivers (first PUT receiver(s)) is configured to output, in response to ultrasound signals of the first frequency F1 arriving along the normal direction, first receiver voltage signals between the respective first electrode and the respective second electrode; and
the signal processing circuitry is configured to read at least some of the first receiver voltage signals.

### Claim 20 (depends on 19)

The system of claim 19, wherein the respective portions of the piezoelectric member at the first PUT receivers oscillate at the first frequency F1 in response to ultrasound signals of the first frequency F1 arriving along the normal direction.

### Claim 21 (depends on 19)

The system of claim 19, wherein the first frequency F1 is in a range of 0.1 MHz to 25 MHz.

### Claim 22 (depends on 19)

The system of claim 19, wherein the signal processing circuitry comprises a high-voltage transceiver circuitry configured to output voltage pulses of 3.3 V or greater, the high-voltage transceiver circuitry being configured to generate the first transmitter voltage signals.

### Claim 23 (depends on 19)

The system of claim 19, wherein at least one of the PFEs and at least one of the PUTs are concentric.

### Claim 24 (depends on 19)

The system of claim 19, additionally comprising a cover layer comprising an outer surface which can be touched by a digit and an inner surface opposite the outer surface, wherein the piezoelectric capacitor assembly is coupled to the inner surface, the piezoelectric capacitor assembly being oriented such that the piezoelectric member faces toward the cover layer, the sense region being at the outer surface.

### Claim 25 (depends on 19)

The system of claim 19, wherein:
for at least one of the PUT transmitters (second PUT transmitter(s)), the signal processing circuitry is additionally configured to generate second transmitter voltage signals that are applied between the respective first electrode and the respective second electrode of the respective second PUT transmitter, upon which the respective second PUT transmitter transmits ultrasound signals of a second frequency F2, in longitudinal mode(s) propagating along the normal direction towards the sense region;
at least one of the PUT receivers (second PUT receiver(s)) is configured to output, in response to ultrasound signals of the second frequency F2 arriving along the normal direction, second receiver voltage signals between the respective first electrode and the respective second electrode; and
the signal processing circuitry is configured to read at least some of the second receiver voltage signals.

### Claim 26 (depends on 25)

The system of claim 25, wherein the respective portions of the piezoelectric member at the second PUT receivers oscillate at the second frequency F2 in response to ultrasound signals of the second frequency F2 arriving along the normal direction.

### Claim 27 (depends on 25)

The system of claim 25, wherein the second frequency F2 is in a range of 0.1 MHz to 25 MHz.

### Claim 28 (depends on 25)

The system of claim 25, wherein the signal processing circuitry comprises a high-voltage transceiver circuitry configured to output voltage pulses of 3.3 V or greater, the high-voltage transceiver circuitry being configured to generate the second transmitter voltage signals.

### Claim 29 (depends on 1)

The system of claim 1, wherein the PFEs are arranged in an array (PFE array).

### Claim 30 (depends on 29)

The system of claim 29, wherein the PFE array is two-dimensional.

### Claim 31 (depends on 30)

The system of claim 30, wherein the piezoelectric capacitors comprise piezoelectric ultrasonic transducers (PUTs) arranged in a two-dimensional array (PUT array), and the PFE array and PUT array overlap.

### Claim 32 (depends on 1)

The system of claim 1, wherein the PFEs are arranged into at least one set of PFEs (PFE set), and the at least one PFE set comprises a plurality of PFEs connected in series.

### Claim 33 (depends on 32)

The system of claim 32, wherein outermost electrodes of the PFEs in the series are connected as differential inputs to an amplifier circuitry of the signal processing circuitry.

### Claim 34 (depends on 33)

The system of claim 33, wherein a node between two adjacent PFEs in the series is a common node.

### Claim 35 (depends on 1)

The system of claim 1, wherein the PFEs are arranged into sets of PFEs (PFE sets), each PFE set comprises two PFEs connected in series, and a node between the two PFEs is a common node.

### Claim 36 (depends on 1)

The system of claim 1, wherein:
the piezoelectric capacitors comprise a haptic transmitter; and
the signal processing circuitry is configured to generate haptic voltage signals that are applied between the respective first electrode and the respective second electrode of the haptic transmitter, upon which the haptic transmitter vibrates at a haptic vibration frequency FH, the haptic vibration frequency FH being in a range of 100 Hz to 1 kHz, the signal processing circuitry generating the haptic voltage signals in accordance with voltage signals read from at least some of the piezoelectric capacitors.

### Claim 37 (depends on 36)

The system of claim 36, wherein the signal processing circuitry comprises a high-voltage transceiver circuitry configured to output voltage pulses of 3.3 V or greater, the high-voltage transceiver circuitry being configured to generate the haptic voltage signals.

### Claim 38 (depends on 1)

The system of claim 1, additionally comprising a touch-sensing subsystem.

### Claim 39 (depends on 38)

The system of claim 38, wherein the touch-sensing subsystem comprises one or more of the following: piezoelectric ultrasonic transducer, capacitive ultrasonic transducer, and capacitive touch panel.

### Claim 40 (depends on 38)

The system of claim 38, additionally comprising a haptic actuator subsystem, wherein the haptic actuator subsystem is actuated in accordance with voltage signals read from at least some of the piezoelectric capacitors and/or inputs received by the touch-sensing subsystem.

### Claim 41 (depends on 40)

The system of claim 40, wherein the haptic actuator subsystem comprises one or more of the following: eccentric rotating mass actuator, linear resonant actuator, and piezoelectric actuator.

### Claim 42

A system, comprising:
a cover layer comprising an outer surface which can be touched by a digit and an inner surface opposite the outer surface;
a piezoelectric capacitor assembly coupled to the inner surface; and
a signal processing circuitry coupled to the piezoelectric capacitor assembly;
wherein the piezoelectric capacitor assembly comprises:
a piezoelectric member; and
a plurality of piezoelectric capacitors located at respective lateral positions along the piezoelectric member, each of the piezoelectric capacitors comprising: (1) a respective portion of the piezoelectric member, (2) a first electrode, and (3) a second electrode, the first electrode and the second electrode being positioned on opposite sides of the piezoelectric member at the respective portion of the piezoelectric member;
wherein the piezoelectric capacitors comprise one or more piezoelectric force-measuring elements (PFEs) and one or more piezoelectric ultrasonic transducers (PUTs);
wherein each of the PFEs is configured to output voltage signals between the respective first electrode and the respective second electrode (PFE voltage signals) in accordance with a time-varying strain at the respective portion of the piezoelectric member between the respective first electrode and the respective second electrode resulting from a low-frequency mechanical deformation;
wherein for at least one of the PUTs, the signal processing circuitry is configured to generate first transmitter voltage signals that are applied between the respective first electrode and the respective second electrode of the respective PUT, upon which the respective PUT transmits ultrasound signals of a first frequency F1, in longitudinal mode(s) propagating along a normal direction approximately normal to the piezoelectric member, at least some of the ultrasound signals propagating towards a sense region of the outer surface;
wherein at least one of the PUTs is configured to output, in response to ultrasound signals of the first frequency F1 arriving along the normal direction, first receiver voltage signals between the respective first electrode and the respective second electrode; and
the signal processing circuitry is configured to read at least some of the PFE voltage signals and at least some of the first receiver voltage signals.

### Claim 43 (depends on 42)

The system of claim 42, wherein the cover layer comprises a material selected from the following: wood, glass, metal, plastic, leather, fabric, and ceramic.

### Claim 44 (depends on 42)

The system of claim 42, wherein the low-frequency mechanical deformation is induced by an excitation at the outer surface having a repetition rate of 100 Hz or less.

### Claim 45 (depends on 44)

The system of claim 44, wherein the repetition rate is 10 Hz or less.

### Claim 46 (depends on 44)

The system of claim 44, wherein the excitation occurs at the outer surface of the cover layer.

### Claim 47 (depends on 44)

The system of claim 44, wherein the excitation occurs at a portion of the system mechanically coupled to the cover layer.

### Claim 48 (depends on 42)

The system of claim 42, wherein the low-frequency mechanical deformation is induced by one or more of the following: touching, pressing, bending, twisting, typing, tapping, and pinching.

### Claim 49 (depends on 42)

The system of claim 42, wherein the low-frequency mechanical deformation is induced by deflection of the cover layer.

### Claim 50

A system, comprising:
a piezoelectric capacitor assembly comprising:
a piezoelectric member; and
one or more piezoelectric capacitors located at respective lateral positions along the piezoelectric member, each of the piezoelectric capacitors comprising: (1) a respective portion of the piezoelectric member, (2) a first electrode, and (3) a second electrode, the first electrode and the second electrode being positioned on opposite sides of the piezoelectric member at the respective portion of the piezoelectric member; and
a signal processing circuitry coupled to the piezoelectric capacitor assembly;
wherein each of the piezoelectric capacitors is configurable by the signal processing circuitry as one or more of the following: piezoelectric force-measuring element (PFE), piezoelectric ultrasonic transducer (PUT) in transmit mode, PUT in receive mode, and haptic transmitter;
when configured as a PFE, the respective piezoelectric capacitor is configured to output voltage signals between the respective first electrode and the respective second electrode (PFE voltage signals) in accordance with a time-varying strain at the respective portion of the piezoelectric member between the respective first electrode and the respective second electrode resulting from a low-frequency mechanical deformation, the signal processing circuitry being configured to read at least some of the PFE voltage signals;
when the respective piezoelectric capacitor is configured as a PUT in transmit mode, the signal processing circuitry is configured to generate first transmitter voltage signals that are applied between the respective first electrode and the second electrode of the respective piezoelectric capacitor, upon which the respective piezoelectric capacitor transmits ultrasound signals of a first frequency F1, in longitudinal mode(s) propagating along a normal direction approximately normal to the piezoelectric member;
when configured as a PUT in receive mode, the respective piezoelectric capacitor is configured to output, in response to ultrasound signals of the first frequency F1 arriving along the normal direction, first receiver voltage signals between the respective first electrode and the respective second electrode, the signal processing circuitry being configured to read at least some of the first receiver voltage signals; and
when the respective piezoelectric capacitor is configured as a haptic transmitter, the signal processing circuitry is configured to generate haptic voltage signals that are applied between the respective first electrode and the respective second electrode of the respective piezoelectric capacitor, upon which the respective haptic transmitter vibrates at a haptic vibration frequency FH, the haptic vibration frequency FH being in a range of 100 Hz to 1 kHz.

### Claim 51

A system, comprising a force-measuring subsystem, a touch-sensing subsystem, and a haptic actuator subsystem, wherein the haptic actuator subsystem is actuated in response to inputs received by the force-measuring subsystem and/or inputs received by the touch-sensing subsystem.

### Claim 52 (depends on 51)

The system of claim 51, wherein the force-measuring subsystem comprises one or more of the following: piezoelectric capacitor force-measuring element and piezoresistive element.

### Claim 53 (depends on 51)

The system of claim 51, wherein the touch-sensing subsystem comprises one or more of the following: piezoelectric ultrasonic transducer, capacitive ultrasonic transducer, and capacitive touch panel.

### Claim 54 (depends on 51)

The system of claim 51, wherein the haptic actuator subsystem comprises one or more of the following: eccentric rotating mass actuator, linear resonant actuator, and piezoelectric actuator.