# US 2019/0174229 A1 · System and Method for a Pumping Speaker

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- Number: US 2019/0174229 A1
- Document ID: US20190174229A1
- Status: Published application
- Kind: A1
- Application number: 16/268,122
- Filed: 2019-02-05
- Published: 2019-06-06
- Earliest claimed: 2015-08-05
- Assignees: Infineon Technologies AG
- Applicants: Infineon Technologies AG
- Inventors: Stefan Barzen
- Web page: https://patentgrep.com/patent/US20190174229A1

## CPC

- H04R 3/06: of electrostatic transducers
- G10K 15/04: Sound-producing devices (G10K15/02 takes precedence)
- H04R 19/005: {using semiconductor materials}
- H04R 29/001: {for loudspeakers (H04R29/007 takes precedence)}
- H04R 2201/003: Mems transducers or their use
- 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)
- G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR

## Abstract

According to an embodiment, a microspeaker includes an acoustic micropump structure configured to pump at a first frequency above an upper audible frequency limit. The acoustic micropump structure is further configured to generate an acoustic signal having a second frequency by adjusting the pumping. Adjusting the pumping includes adjusting a direction of pumping for the acoustic micropump structure according to the second frequency. Adjusting the direction of pumping includes changing a direction of flow of an elastic medium through the acoustic micropump structure from a first direction to a second direction. The second frequency is below the upper audible frequency limit.

## Claims

### Claim 1

A microspeaker comprising:
an acoustic micropump structure configured to
pump at a first frequency above an upper audible frequency limit; and
generate an acoustic signal having a second frequency by adjusting the pumping, wherein
adjusting the pumping comprises adjusting a direction of pumping for the acoustic micropump structure according to the second frequency,
adjusting the direction of pumping comprises changing a direction of flow of an elastic medium through the acoustic micropump structure from a first direction to a second direction, and
the second frequency is below the upper audible frequency limit.

### Claim 2 (depends on 1)

The microspeaker of claim 1, wherein generating the acoustic signal by adjusting the direction of pumping comprises adjusting a magnitude of the pumping according to the second frequency.

### Claim 3 (depends on 1)

The microspeaker of claim 1, wherein
the second frequency comprises a plurality of frequencies below the upper audible frequency limit; and
the acoustic signal comprises a plurality of sounds having the plurality of frequencies below the upper audible frequency limit.

### Claim 4 (depends on 1)

The microspeaker of claim 1, wherein the first frequency is selected to match a resonant frequency of the acoustic micropump structure.

### Claim 5 (depends on 1)

The microspeaker of claim 1, wherein the first frequency is held constant and the second frequency is varied.

### Claim 6 (depends on 1)

The microspeaker of claim 1, further comprising an integrated circuit coupled to the acoustic micropump structure and configured to:
excite the acoustic micropump structure at a plurality of frequencies;
measure a plurality of responses of the acoustic micropump structure corresponding to the plurality of frequencies; and
determine a resonant frequency of the acoustic micropump structure based on measuring the plurality of responses.

### Claim 7

A microspeaker comprising:
a plurality of electrodes comprising a first electrode and a second electrode;
an upper backplate comprising
a first set of electrical partitions electrically coupled to the first electrode, and
a second set of electrical partitions electrically coupled to the second electrode;
a lower backplate;
a flexible membrane disposed between the upper backplate and the lower backplate;
wherein the plurality of electrodes are configured to cause the flexible membrane to oscillate at a first frequency above an upper audible frequency limit; and
wherein the plurality of electrodes are configured to generate an acoustic signal having a second frequency below the upper audible frequency limit by adjusting the oscillating of the flexible membrane; and
wherein adjusting the oscillating of the flexible membrane comprises simultaneously applying different voltages to the first electrode and the second electrode.

### Claim 8 (depends on 7)

The microspeaker of claim 7, wherein:
the plurality of electrodes further comprises a third electrode and a fourth electrode;
the lower backplate comprises
a third set of electrical partitions electrically coupled to the third electrode, and
a fourth set of electrical partitions electrically coupled to the fourth electrode; and
the adjusting the oscillating of the flexible membrane further comprises simultaneously applying different voltages to the third electrode and the fourth electrode.

### Claim 9 (depends on 8)

The microspeaker of claim 8, wherein:
the flexible membrane is a partitioned membrane comprising a first set of membrane partitions and a second set of membrane partitions;
the first electrode and the third electrode are each configured to generate attractive forces on the first set of membrane partitions; and
the second electrode and the fourth electrode are each configured to generate attractive forces on the second set of membrane partitions.

### Claim 10 (depends on 9)

The microspeaker of claim 9, wherein the partitioned membrane further comprises slits separating ones of the first set of membrane partitions from adjacent ones of the second set of membrane partitions, and wherein each of the first set of membrane partitions and each of the second set of membrane partitions are configured to move separately.

### Claim 11 (depends on 7)

The microspeaker of claim 7, wherein the flexible membrane further comprises valves, and wherein generating the acoustic signal further comprises controlling opening and closing of the valves.

### Claim 12 (depends on 7)

The microspeaker of claim 7, wherein:
the upper backplate further comprises an upper perforated section;
the lower backplate further comprises a lower perforated section vertically misaligned with the upper perforated section; and
the plurality of electrodes is further configured to generate a serpentine movement of the flexible membrane horizontally between the upper perforated section and the lower perforated section.

### Claim 13 (depends on 7)

The microspeaker of claim 7, wherein generating the acoustic signal further comprises changing a direction of flow of an elastic medium through the microspeaker from a first direction to a second direction.

### Claim 14

A method of operating a microspeaker, the method comprising:
pumping at a first frequency above an upper audible frequency limit by causing a flexible membrane to oscillate using a plurality of electrodes, wherein
the plurality of electrodes comprise a first electrode and a second electrode,
the first electrode is electrically coupled to a first set of electrical partitions of an upper backplate of the microspeaker, and
the second electrode is electrically coupled to a second set of electrical partitions of the upper backplate; and
simultaneously applying different voltages to the first electrode and the second electrode to adjust the pumping of the flexible membrane to generate an acoustic signal having a second frequency below the upper audible frequency limit.

### Claim 15 (depends on 14)

The method of claim 14, further comprising:
simultaneously applying different voltages to a third electrode and a fourth electrode to adjust the oscillating of the flexible membrane, wherein
the plurality of electrodes further comprises the third electrode and the fourth electrode,
the third electrode is electrically coupled to a third set of electrical partitions of a lower backplate of the microspeaker, and
the fourth electrode is electrically coupled to a fourth set of electrical partitions of the lower backplate.

### Claim 16 (depends on 15)

The method of claim 15, further comprising:
generating a serpentine movement of the flexible membrane using the plurality of electrodes, wherein
the upper backplate comprises an upper perforated section,
the lower backplate comprises a lower perforated section vertically misaligned with the upper perforated section, and
the serpentine movement comprises horizontal movement between the upper perforated section and the lower perforated section.

### Claim 17 (depends on 14)

The method of claim 14, further comprising:
generating a first attractive force on a first set of membrane partitions of the flexible membrane using the first electrode; and
generating a second attractive force on a second set of membrane partitions of the flexible membrane using the second electrode.

### Claim 18 (depends on 17)

The method of claim 17, wherein:
the flexible membrane further comprises slits separating ones of the first set of membrane partitions from adjacent ones of the second set of membrane partitions;
generating the first attractive force on the first set of membrane partitions comprises moving the first set of membrane partitions separately from the second set of membrane partitions; and
generating the second attractive force on the second set of membrane partitions comprises moving the second set of membrane partitions separately from the first set of membrane partitions.

### Claim 19 (depends on 14)

The method of claim 14, further comprising:
controlling opening and closing of valves of the flexible membrane to generate the acoustic signal.

### Claim 20 (depends on 14)

The method of claim 14, wherein generating the acoustic signal further comprises changing a direction of flow of an elastic medium through the microspeaker from a first direction to a second direction.