Abstract: The present invention provides a process of fabricating a capacitive microphone such as a MEMS microphone with two capacitors. The two capacitors may be so fabricated that the signal output from the first capacitor is additive inverse of that from the second capacitor, and a total signal output is a difference between the two outputs. In at least one of the two capacitors, a movable or deflectable membrane/diaphragm moves in a lateral manner relative to the fixed capacitor plate, instead of moving toward/from the fixed plate. The squeeze film damping, and the noise are substantially avoided, and the performances of the microphone are significantly improved.

Abstract: A Coriolis mass flow sensor uses a multiple-loops form of sensing tube and combined it with a middle post. The resulted sensing tube has high swing stiffness and low twist stiffness and this increases the sensitivity of the sensor tremendously.

Abstract: The present invention provides a process for fabricating a capacitive microphone such as a MEMS microphone. In the microphone, a movable or deflectable membrane/diaphragm may be so fabricated that it moves in a lateral manner relative to a fixed backplate, instead of moving toward/from the fixed backplate. The fixed backplate may be so fabricated that it includes an electrical insulator sandwiched between two sub-conductors to cancel systematic/background noise. The squeeze film damping is substantially avoided, and the performance, such as signal to noise ratio, of the fabricated microphone is significantly improved.

Abstract: A plug restrictor has surface channel(s) made by etching or other means. The plug is either tapered to match with the tapered bore in the flow apparatus or straight to match with the straight bore of the flow apparatus. By pressing the plug restrictor into the bore of the flow apparatus, the restricting passageway(s) is(are) formed between the channel(s) on the plug surface and the inner peripheral surface of the bore of the flow apparatus.

Abstract: A U-shaped tube is used to measure the mass flow rate of the fluid using both thermal method and the Coriolis principle simultaneously. Two resistant coils are wound on the tube to do the thermal measurement and an excitation coil and two optical sensors are used to do the Coriolis flow measurement. It takes the advantages of both technologies and create a flow sensor which is super accurate, gas type insensitive, long-term stable and fast responsive without too much pressure drop.

Abstract: The present invention provides a general MEMS device having a pair of quadrilateral insert and trench. An air channel/space includes a first internal wall and a second internal wall for air to flow between. A quadrilateral trench is recessed from the first internal wall, and a quadrilateral insert is extended from the second internal wall and inserted into the trench. In capacitive MEMS microphone, the spatial relationship between the insert and the trench can vary or oscillate. The quadrilateral insert & trench serve as an air flow restrictor or a leakage prevention structure which keeps the sound frequency response plot of the microphone flatter in the range of 20 Hz to 1000 Hz. The level of the air resistance may be controlled e.g. by the depth of quadrilateral trench/slot etched on the substrate.

Abstract: The present invention provides a MEMS device such as a capacitive MEMS microphone that comprises a new design of air flow restrictor having a pair of continuous looped insert and trench. An air channel/space includes a first internal wall and a second internal wall for air to flow between. A continuous looped trench is recessed from the first internal wall, and a continuous looped insert is extended from the second internal wall and inserted into the trench. The spatial relationship between the insert and the trench can vary or oscillate. Air resistance of the channel/space may be controlled by the trench's depth. The invention has a significant effect on, for example, keeping the sound frequency response plot more flat on the low frequency part ranging from 20 Hz to 1000 Hz.

Abstract: The present invention provides a capacitive microphone such as a MEMS microphone with two capacitors. The signal output from the first capacitor is additive inverse of that from the second capacitor, and a total signal output is a difference between the two outputs. In at least one of the two capacitors, a movable or deflectable membrane/diaphragm moves in a lateral manner relative to the fixed capacitor plate, instead of moving toward/from the fixed plate. The squeeze film damping, and the noise are substantially avoided, and the performances of the microphone is significantly improved.

Abstract: The present invention provides a capacitive microphone such as a MEMS microphone with two capacitors. The signal output from the first capacitor is additive inverse of that from the second capacitor, and a total signal output is a difference between the two outputs. In at least one of the two capacitors, a movable or deflectable membrane/diaphragm moves in a lateral manner relative to the fixed capacitor plate, instead of moving toward/from the fixed plate. The squeeze film damping, and the noise are substantially avoided, and the performances of the microphone is significantly improved.

Abstract: The present invention provides a process of fabricating a capacitive microphone such as a MEMS microphone. In the process, one electrically conductive layer is deposited on a removable layer, and then divided or cut into two divided layers, both of which remain in contact with the removable layer as they were. One of the two divided layers will become or include a movable or deflectable membrane/diaphragm that moves in a lateral manner relative to another layer, instead of moving toward/from another layer. A motional sensor is optionally fabricated within the microphone to estimate the noise introduced from acceleration or vibration of the microphone for the purpose of compensating the microphone output through a signal subtraction operation.

Abstract: The present invention provides a process of fabricating a capacitive microphone such as a MEMS microphone. In the process, one electrically conductive layer is deposited on a removable layer, and then divided or cut into two divided layers, both of which remain in contact with the removable layer as they were. One of the two divided layers will become or include a movable or deflectable membrane/diaphragm that moves in a lateral manner relative to another layer, instead of moving toward/from another layer. A motional sensor is optionally fabricated within the microphone to estimate the noise introduced from acceleration or vibration of the microphone for the purpose of compensating the microphone output through a signal subtraction operation.

Abstract: The present invention provides a capacitive microphone including a MEMS microphone. In the microphone, a movable or deflectable membrane/diaphragm moves in a lateral manner relative to a fixed backplate, instead of moving toward/from the fixed backplate. The fixed backplate includes an electrical insulator sandwiched between two sub-conductors to cancel systematic/background noise. The squeeze film damping is substantially avoided, and the performance, such as signal to noise ratio, of the microphone is significantly improved.

Abstract: A wound foil restrictor is fabricated by winding isolating foil and flow foil on a mandrel. The flow foil is made by etching multiple through flow channels for one or more restrictors; in the latter case, the restrictors will be wound at once and cut into several restrictors by laser, plasma or water jet.

Abstract: A valve apparatus has both solenoid and pneumatic drivers. Solenoid controls the flow rate, and pneumatic driver will provide a seal force to realize near zero sealing wherever needed. Pneumatic driver uses welded diaphragm cylinder structure so the whole system is small enough to fit into the case of a mass flow controller. The valve apparatus uses a diaphragm structure and the diaphragm is directly over the valve seat, so all other valve components will not expose to process gases. The valve apparatus is equipped with means to adjust air gap and preload force. A spacing spring is used to keep the centering of the plunger to avoid the friction between plunger and bearing as the conventional solenoid valves have. The solenoid driver can work alone with pneumatic driver removed wherever there is no close to zero sealing needed.

Abstract: The present invention provides a capacitive microphone having a capability of acceleration noise cancelation. The microphone includes (1) a moveable functional membrane comprising a basic functional membrane with an area Ao; and (2) a moveable reference membrane comprising a basic reference membrane. The basic reference membrane has one or more holes through the membrane's thickness, and the moveable reference membrane would be identical to the moveable functional membrane if the basic reference membrane does not have said one or more holes. The total area of said one or more holes is Ah, and a hole density HD is defined as Ah/Ao (%), and HD is in the range of e.g. from 0.012% to 2.647%.

Abstract: A variable capacitance type pressure transducer is constructed by electrically conductive diaphragm and electrode disposed on the surface of a dielectric disk. The gap between electrode and diaphragm is formed and solely decided by a spacer made of Super Invar or Invar, which has extra low thermal expansion coefficient. The gap between the electrode and the diaphragm is formed easily and almost no change when temperature of the transducer changes. The dielectric disk is centered with diaphragm radically by a mating between a pin made on the top lid of the pressure transducer and a center hole on the dielectric disk.

Abstract: A variable capacitance type pressure sensor is constructed by only using semi-conductor industry accepted metals and materials in the wetted surface. PCTFE or PTFE by injection molding or compression molding is used to join components together and provide sealing and electrical isolation. No oil filling is needed. The sensor can measure both differential pressure and line pressure. Implanted temperature sensor is used to do thermal calibration and temperature compensation.

Abstract: The present invention provides a MEMS device such as a capacitive MEMS microphone that comprises a new design of air flow restrictor having a pair of continuous looped insert and trench. An air channel/space includes a first internal wall and a second internal wall for air to flow between. A continuous looped trench is recessed from the first internal wall, and a continuous looped insert is extended from the second internal wall and inserted into the trench. The spatial relationship between the insert and the trench can vary or oscillate. Air resistance of the channel/space may be controlled by the trench's depth. The invention has a significant effect on, for example, keeping the sound frequency response plot more flat on the low frequency part ranging from 20 Hz to 1000 Hz.

Abstract: The present invention provides a MEMS device such as a capacitive MEMS microphone that comprises a new design of air flow restrictor. An air channel includes a first internal wall and a second internal wall for air to flow between. A trench is recessed from the first internal wall, and an insert is extended from the second internal wall and inserted into the trench. The spatial relationship between the insert and the trench can vary or oscillate. Air resistance of the channel may be controlled by the trench depth. The air resistance is higher with a deeper trench. The invention has a significant effect on, for example, keeping the sound frequency response plot more flat on the low frequency part ranging from 20 Hz to 1000 Hz.

Abstract: The present invention provides a capacitive microphone having a capability of acceleration noise cancelation. The microphone includes (1) a moveable functional membrane comprising a basic functional membrane with an area Ao; and (2) a moveable reference membrane comprising a basic reference membrane. The basic reference membrane has one or more holes through the membrane's thickness, and the moveable reference membrane would be identical to the moveable functional membrane if the basic reference membrane does not have said one or more holes. The total area of said one or more holes is Ah, and a hole density HD is defined as Ah/Ao (%), and HD is in the range of e.g. from 0.012% to 2.647%.