Micro-speaker device
A speaker device comprises a housing having an acoustic aperture, a transducer element in the housing configured to receive a first actuation signal and to generate an acoustic output signal. The speaker device comprises a shutter element in the housing configured to receive a second actuation signal and arranged laterally offset to the transducer in the housing. The shutter element is arranged in an acoustic path between the transducer element and the acoustic aperture and comprises a shutter portion movable in opposite directions in response to the second actuation signal. A controller provides the first actuation signal to the transducer element, while the first actuation signal has an ultrasonic signal component modulated with an audio signal component. The controller provides the second actuation signal to the shutter element that has half the frequency of the ultrasonic signal component.
1 . A speaker device comprising:
a housing having an acoustic aperture;
a transducer element in the housing configured to receive a first actuation signal and to generate an acoustic output signal in response to the first actuation signal;
a shutter element in the housing configured to receive a second actuation signal, wherein the shutter element is arranged in an acoustic path between the transducer element and the acoustic aperture and comprises a movable shutter portion, which is movable in opposite directions in response to the second actuation signal; and
a controller configured to provide the first actuation signal to the transducer element, wherein the first actuation signal has an ultrasonic signal component which is modulated with an audio signal component, and the controller is further configured to provide the second actuation signal to the shutter element, wherein the second actuation signal has a second frequency that is half of a first frequency of the ultrasonic signal component,
wherein the shutter element further comprises a stationary portion surrounding the movable shutter portion,
wherein the movable shutter portion, in a closed condition, is aligned in parallel to or in a common plane with the stationary portion of the shutter element,
wherein the movable shutter portion comprises a first shutter portion and a second shutter portion, which are movable in opposite directions in response to the second actuation signal, wherein the first shutter portion comprises a first cantilever element, and the second shutter portion comprises a second cantilever element, and wherein the first shutter portion and the second shutter portion are arranged laterally adjacent to each other, and
wherein the movable shutter portion comprises a disc element which is tiltable around a tilting axis, wherein the first shutter portion and the second shutter portion extend in opposite directions from the tilting axis.
2 . The speaker device of claim 1 , wherein the shutter element spans the acoustic path.
3 . The speaker device of claim 1 , wherein the movable shutter portion is movable in opposite directions in response to the second actuation signal.
4 . The speaker device of claim 3 , wherein the movable shutter portion comprises a cantilever element.
5 . The speaker device of claim 1 , wherein the tilting axis is a central axis through a center of gravity of the disc element.
6 . The speaker device of claim 1 , wherein the shutter element is configured to provide consecutive open and closed conditions of the acoustic path based on the second actuation signal, wherein the shutter element is configured to comprise two closed conditions during one period of the second actuation signal.
7 . The speaker device of claim 1 , wherein the transducer element comprises a piezo-electrically actuated membrane structure or a cantilever structure.
8 . The speaker device of claim 1 , wherein the transducer element and the shutter element are arranged in the same plane in the housing.
9 . The speaker device of claim 1 , wherein a center distance between the transducer element and the shutter element is less than one quarter of a wavelength of the ultrasonic signal component.
10 . The speaker device of claim 1 , wherein the first frequency corresponds within a range of +/−10% to a first resonance frequency of the transducer element, and wherein the second frequency corresponds within a range of +/−5% to a second resonance frequency of the shutter element.
11 . A speaker device comprising:
a housing having an acoustic aperture;
a transducer element in the housing configured to receive a first actuation signal and to generate an acoustic output signal in response to the first actuation signal;
a shutter element in the housing configured to receive a second actuation signal, and wherein the shutter element is arranged in an acoustic path between the transducer element and the acoustic aperture and comprises at least one movable shutter portion movable in opposite directions in response to the second actuation signal; and
a controller configured to:
provide the first actuation signal to the transducer element, wherein the first actuation signal has an ultrasonic signal component that is modulated with an audio signal component; and
provide the second actuation signal to the shutter element, wherein the second actuation signal has half a frequency of the ultrasonic signal component,
wherein the shutter element is configured to:
provide consecutive open and closed conditions of the acoustic path based on the second actuation signal, and
comprise two closed conditions during one period of the second actuation signal, and
wherein the at least one movable shutter portion is configured to provide the closed condition when arranged in a closing position and to provide open conditions when being moved in either of the opposite directions.
12 . The speaker device of claim 11 , wherein the shutter element spans the acoustic path.
13 . The speaker device of claim 11 , wherein the shutter element further comprises a stationary portion that surrounds the movable shutter portion.
14 . The speaker device of claim 13 , wherein the movable shutter portion of the shutter element is in a closed condition aligned in parallel to or in the same plane with the stationary portion of the shutter element.
15 . The speaker device of claim 11 , wherein the movable shutter portion of the shutter element comprises a single movable shutter portion, which is movable in opposite directions in response to the second actuation signal.
16 . The speaker device of claim 15 , wherein the single movable shutter portion comprises a cantilever element.
17 . The speaker device of claim 11 ,
wherein the movable shutter portion of the shutter element comprises a first movable shutter portion and a second movable shutter portion, which are movable in opposite directions in response to the second actuation signal,
wherein the first movable shutter portion comprises a first cantilever element or a first group of cantilever elements and the second movable shutter portion comprises a second cantilever element or a second group of cantilever elements, and
wherein the first and second movable shutter portions are arranged laterally adjacent to each other.
18 . The speaker device of claim 11 , wherein the movable shutter portion of the shutter element comprises a disc element, which is tiltable around a tilting axis, wherein a first and second movable shutter portions of the disc element extend in opposite directions from the tilting axis.
19 . The speaker device of claim 18 , wherein the tilting axis is a central axis through the center of gravity of the disc element.
20 . The speaker device of claim 11 , wherein the transducer element comprises a piezo-electrically actuated membrane structure or a cantilever structure.