Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalisation of the air volumes above and below the membrane.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalisation of the air volumes above and below the membrane.

Abstract: The application describes a MEMS transducer comprising a layer of conductive material provided on a surface of a layer of membrane material. The layer of conductive material comprises first and second regions, wherein the thickness and/or the conductivity of the/each first and second regions is different.

Abstract: The application describes MEMS transducer having a flexible membrane and which seeks to alleviate and/or redistribute stresses within the membrane layer. A membrane having a first/active region and a second/inactive region is described.

Abstract: The application describes MEMS transducers having a vent structure provided in a flexible membrane of the vent structure The vent structure comprises at least one moveable portion and the vent structure is configured such that, in response to a differential pressure across the vent structure, the moveable portion is rotatable about first and second axes of rotation, which axes of rotation extend in the plane of the membrane.

Abstract: A MEMS transducer configured to operate as a microphone, the MEMS transducer comprising a flexible membrane, the flexible membrane having a first surface and a second surface, wherein the first surface of the flexible membrane is fluidically isolated from the second surface of the flexible membrane. Also, a MEMS device comprising a MEMS transducer, an electronic device comprising a MEMS transducer and/or a MEMS device, and a method for forming a MEMS device.

Abstract: A MEMS transducer structure comprises a substrate comprising a cavity. A membrane layer is supported relative to the substrate to provide a flexible membrane. A peripheral edge of the cavity defines at least one perimeter region that is convex with reference to the center of the cavity. The peripheral edge of the cavity may further define at least one perimeter region that is concave with reference to the center of the cavity.

Abstract: The application describes improvements to (MEMS) transducers (100) having a flexible membrane (301) with a membrane electrode (302), especially where the membrane is crystalline or polycrystalline and the membrane electrode is metal or a metal alloy. Such transducers may typically include a back-plate having at least one back-plate layer (304) coupled to a back-plate electrode (303), with a plurality of holes (314) in the back-plate electrode corresponding to a plurality back-plate holes (312) through the back-plate. In embodiments of the invention the membrane electrode has at least one opening (313) in the membrane electrode wherein, at least part of the area of the opening corresponds to the area of at least one back-plate hole, in a direction normal to the membrane, and there is no hole in the flexible membrane at said opening in the membrane electrode. There may be a plurality of such openings. The openings effectively allow a reduction in the amount of membrane electrode material, e.g.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalisation of the air volumes above and below the membrane.

Abstract: This application relates to MEMS devices, especially MEMS capacitive transducers and to processes for forming such MEMS transducer that provide increased robustness and resilience to acoustic shock. The application describes a MEMS transducer (400) having at least one membrane layer (101) supported so as to define a flexible membrane. A strengthening layer (401; 701) is mechanically coupled to the membrane layer and is disposed around the majority of a peripheral area of the flexible membrane but does not extend over the whole flexible membrane. The strengthening layer, which in some embodiments may be formed from the same material as the membrane electrode (102) being disposed in the peripheral area helps reduce stress in membrane at locations that otherwise may be highly stressed in acoustic shock situations. The membrane may be supported over a substrate cavity and the strengthening layer may be provided in an area of the membrane that could make contact with the edge (202) of the substrate cavity.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalization of the air volumes above and below the membrane.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalization of the air volumes above and below the membrane.

Abstract: A system of nodes may communicate a signal between nodes in a manner that prevents looping the same signal through the same node. When a node receives a signal, it may evaluate whether the signal itself includes an identifier of the receiving node, indicating whether or not the receiving node has previously broadcast the signal. The receiving node may have an internal memory with a record of previously broadcast signals, against which it may compare a received signal to determine if the received signal is one that has been previously broadcast. If the signal has previously been broadcast, then the receiving node may discard the signal. If the signal has not previously been broadcast, then the receiving node may add its own unique identifier to the signal and rebroadcast the signal. The internal memory of the receiving node may also be updated to reflect the broadcast.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalisation of the air volumes above and below the membrane.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalization of the air volumes above and below the membrane.

Abstract: A Roots pump comprises a plurality of multi-toothed rotary pumps, each forming a pump stage, and connection channels connecting respective adjacent pump stages. The invention provides that the connection channels are arranged in partitioning walls separating the adjacent pump stages.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalisation of the air volumes above and below the membrane.

Abstract: A vacuum pump comprises pumping elements arranged in a pumping chamber. An electric motor drives the pumping element. A frequency inverter is provided for changing the rotational speed of the electric motor. The frequency inverter is arranged in a frequency inverter housing immediately connected to the pump housing. An air cooler and a liquid cooler are arranged in the frequency inverter housing to cool the frequency inverter.

Abstract: A MEMS capacitive transducer with increased robustness and resilience to acoustic shock. The transducer structure includes a flexible membrane supported between a first volume and a second volume, and at least one variable vent structure in communication with at least one of the first and second volumes. The variable vent structure includes at least one moveable portion which is moveable in response to a pressure differential across the moveable portion so as to vary the size of a flow path through the vent structure. The variable vent may be formed through the membrane and the moveable portion may be a part of the membrane, defined by one or more channels, that is deflectable away from the surface of the membrane. The variable vent is preferably closed in the normal range of pressure differentials but opens at high pressure differentials to provide more rapid equalization of the air volumes above and below the membrane.