MEMS sound transducer having recesses and projections

1 . A method for manufacturing an MEMS sound transducer for generating sound, comprising:

providing an actuator and a surrounding structure, wherein the actuator is separated from the surrounding structure by one or more gaps and is configured to execute a relative movement between the actuator and the surrounding structure, and

wherein the actuator and the surrounding structure comprise a plurality of recesses and projections, wherein the plurality of projections belonging to the actuator are arranged to interdigitate into the plurality of recesses belonging to the surrounding structure, and/or the plurality of projections belonging to the surrounding structure to interdigitate into the plurality of recesses belonging to the actuator,

forming the interdigitating elements such that the interdigitating elements are thus separated by the one or more gaps, and such that overlapping areas of the plurality of recesses and projections are configured such that the interdigitating elements comprise a frequency-depending attenuation function with a relative movement between the actuator and the surrounding structure to suppress harmonic distortions; and

wherein the overlapping areas are directly opposite areas moving past each other by the relative movement.

2 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein an aspect ratio of height/width of the plurality of recesses and projections, the overlapping areas of actuator and surrounding structure which move past each other by the relative movement, and the distance of the overlapping areas of actuator and surrounding structure are configured to adjust a frequency-dependent attenuation to suppress harmonic distortions,

wherein the height is a height orthogonally to a surface of the actuator or the surrounding structure on which the projection is arranged, and wherein the width is a width in parallel to the surface of the actuator or the surrounding structure on which the projection is arranged.

3 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the surrounding structure is formed by a substrate.

4 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the plurality of recesses and projections are implemented as microstructures comprising an aspect ratio between height/width of more than 5, wherein the height is a height orthogonally to a surface of the actuator or the surrounding structure on which the projection is arranged; and

wherein the width is a width in parallel to the surface of the actuator or the surrounding structure on which the projection is arranged.

5 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the actuator comprises a piezoelectric or magnetic or electrostatic drive; and/or

wherein the actuator is formed by a bending transducer.

6 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the projections of the plurality of projections comprise a height of more than 50 μm, and wherein the height is a height orthogonally to a surface of the actuator or the surrounding structure on which the respective projection is arranged.

7 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the plurality of projections are implemented as columns and/or combs, and wherein the plurality of recesses are implemented as holes and/or slots.

8 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the plurality of recesses and projections are made of at least one of silicon, silicon compounds, metals or polymers.

9 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the MEMS sound transducer is configured to generate signals in a frequency range of at least 20 Hz and/or up to 20 kHz; and/or

wherein the MEMS sound transducer is an MEMS ultrasonic transducer, the MEMS ultrasonic transducer being configured to generate signals in a frequency range of at least 20 kHz and/or up to 100 MHz.

10 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the one or more gaps comprise a width of less than 20 μm, less than 10 μm or less than 5 μm, or, generally, comprise a width in a range between 0.1 and 20 μm.

11 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the actuator is implemented as a bending actuator, and wherein the bending actuator and the surrounding structure are laterally opposite each other in a plane; and

wherein the bending actuator is suspended relative to the surrounding structure at least on one side; and

wherein the bending actuator is configured to execute, with an end of the bending actuator, the relative movement between the bending actuator and the surrounding structure at least partially perpendicularly to the plane; and

wherein, at the moveable end of the bending actuator, a plurality of recesses and/or projections in the form of a first comb structure are implemented, in the common plane of the bending actuator and the surrounding structure; and

wherein the surrounding structure comprises a plurality of recesses and/or projections in the form of a second comb structure on a side facing the movable end of the bending actuator, wherein the first and second comb structures are configured to interdigitate.

12 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the actuator is implemented as a lifting actuator, and wherein the lifting actuator and the surrounding structure are arranged in a plane; and

wherein the lifting actuator is configured to execute the relative movement between the lifting actuator and the surrounding structure perpendicularly to the plane; and

wherein the lifting actuator comprises a plurality of recesses and/or projections in the form of a first comb structure along its periphery in the plane; and

wherein the surrounding structure comprises a plurality of recesses and/or projections in the form of a second comb structure on a side facing the first comb structure; and

wherein the first and the second comb structures are configured to interdigitate.

13 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the actuator is arranged in a first plane, and wherein the surrounding structure is arranged in a second plane, the first and second planes being parallel to each other; and

wherein the actuator is configured to execute the relative movement between the actuator and the surrounding structure perpendicularly to the first and second planes; and

wherein the actuator comprises a plurality of projections in the form of columns and/or combs, wherein the columns and/or combs are arranged on a surface of the actuator facing the surrounding structure, perpendicularly to the parallel planes; and

wherein the surrounding structure comprises a plurality of recesses in the form of holes and/or slots; and

wherein the columns and/or combs of the actuator and the holes and/or slots of the surrounding structure are configured to interdigitate.

14 . The method for manufacturing an MEMS sound transducer in accordance with claim 1 , wherein the surrounding structure is arranged in a first plane, and wherein the actuator is arranged in a second plane, the first and second planes being parallel to each other; and

wherein the actuator is configured to execute the relative movement between the actuator and the surrounding structure perpendicularly to the first and second planes; and

wherein the surrounding structure comprises a plurality of projections in the form of columns and/or combs, wherein the columns and/or combs are arranged on a surface of the surrounding structure facing the actuator, perpendicularly to the parallel planes; and

wherein the actuator comprises a plurality of recesses in the form of holes and/or slots; and

wherein the columns and/or combs of the surrounding structure and the holes and/or slots of the actuator are configured to interdigitate.

15 . An MEMS sound transducer for generating sound, comprising:

an actuator, wherein the actuator is separated from a surrounding structure by one or more gaps and is configured to execute a relative movement between the actuator and the surrounding structure, and

the surrounding structure, wherein the actuator and the surrounding structure comprise a plurality of recesses and projections, wherein the plurality of projections belonging to the actuator are arranged to interdigitate into the plurality of recesses belonging to the surrounding structure, and/or the plurality of projections belonging to the surrounding structure to interdigitate into the plurality of recesses belonging to the actuator, wherein the interdigitating elements are separated by one or more gaps, and

wherein the interdigitating elements are separated by one or more gaps such that the interdigitating elements comprise an attenuation function with a relative movement between the actuator and the surrounding structure; and

wherein the actuator is arranged in a first plane, and wherein the surrounding structure is arranged in a second plane, the first and second planes being parallel to each other, and

wherein the actuator comprises a plurality of projections in the form of columns and/or combs, wherein the columns and/or combs are arranged on a surface of the actuator facing the surrounding structure, perpendicularly to the parallel planes, and

wherein the surrounding structure comprises a plurality of recesses in the form of holes and/or slots, and

wherein the columns and/or combs of the actuator and the holes and/or slots of the surrounding structure are configured to interdigitate, and

wherein the actuator is configured to execute the relative movement between the actuator and the surrounding structure perpendicularly to the first and second planes and perpendicularly to the surface of the actuator on which the columns and/or combs are arranged; and/or

wherein the surrounding structure is arranged in a first plane, and wherein the actuator is arranged in a second plane, the first and second planes being parallel to each other, and

wherein the surrounding structure comprises a plurality of projections in the form of columns and/or combs, wherein the columns and/or combs are arranged on a surface of the surrounding structure facing the actuator, perpendicularly to the parallel planes, and

wherein the actuator comprises a plurality of recesses in the form of holes and/or slots, and

wherein the columns and/or combs of the surrounding structure and the holes and/or slots of the actuator are configured to interdigitate,

wherein the actuator is configured to execute the relative movement between the actuator and the surrounding structure perpendicularly to the first and second planes and perpendicularly to the surface of the surrounding structure on which the columns and/or combs are arranged.