145 results about "Reference cavity" patented technology

Methods of bulk manufacturing high temperature sensor sub-assembly packages are disclosed and claimed. Sensors are sandwiched between a top cover and a bottom cover so as to enable the peripheries of the top covers, sensors and bottom covers to be sealed and bound securely together are disclosed and claimed. Sensors are placed on the bottom covers leaving the periphery of the bottom cover exposed. Likewise, top covers are placed on the sensors leaving the periphery of the sensor exposed. Individual sensor sub-assemblies are inserted into final packaging elements which are also disclosed and claimed. Methods of directly attaching wires or pins to contact pads on the sensors are disclosed and claimed. Sensors, such as pressure sensors and accelerometers, and headers made out of silicon carbide and aluminum nitride are disclosed and claimed. Reference cavities are formed in some embodiments disclosed and claimed herein where top covers are not employed.

The invention relates to an integrated silicon chip for testing acceleration, pressure and temperature, and the manufacturing method thereof. The invention is characterized in manufacturing the pressure sensor, temperature sensor and accelerometers of thermoelectric pile on to one chip by the same micro processing technology. The acceleration is detected by adopting thermal convection type accelerometers, using polysilicon resistor as heater, using a thermoelectric pile composed of two pairs of metals (such as aluminium and tungsten-titanium) and P type or N type polysilicon to detect the temperature difference in the sealed cavity caused by acceleration. The high accurate absolute pressure sensor is manufactured by using silicon nitride film with low stress as the core structure layer of the pressure sensor chip, and forming force sensitive resistor track by polysilicon film, forming vacuum reference cavity by TEOS bolt in LPCVD furnace. At the same time, the temperature sensor is composed by using polysilicon thermistor to detect temperature change. The integrated chip achieves the advantages of microminiaturization, low cost, high precision, high reliability and high stability.

A fiber laser gas detection system with a double wavelength combination using reference cavity compensation is provided. The system comprises an optical fiber laser respectively emitting beams having a first and second wavelengths, which consists of a laser diode pump source, a first wavelength division multiplexer, an active optical fiber, a first fiber bragg grating and a second fiber bragg grating connected successively; an optical isolator; a coupler for dividing the beams according to power ratio, the divided beams is introduced into a reference gas chamber and a detecting gas chamber respectively; a second wavelength division multiplexer connecting the reference room and a third wavelength division multiplexer connecting the detecting gas chamber; a first, a second, a third and a fourth photoelectric detector; a feedback control unit, receiving the first to fourth light intensity signals and adjusting the fiber laser using the comparison results as a feedback signal.

The invention discloses a tire pressure monitoring alarm device, which comprises a bottom nut which is screwed at a valve core and a shell which is screwed on the nut, the top of the shell is sealed by a lens, and the shell is internally provided with an alarm circuit board, a battery, an elastic metal sheet, a reference cavity component and an inflating valve spring sequentially from top to bottom; the anode of the alarm circuit board is connected with the anode of the battery, and the cathode of the alarm circuit board is connected with the elastic metal sheet below the cathode of the battery; and the elastic metal sheet attaches to another elastic metal sheet on the top surface of a reference cavity at the top of the reference cavity component, and the space above the reference cavity inside the shell is sealed as a monitoring cavity. The pressure of the reference cavity and the initial pressure of the tire are the same, the pressure in the monitoring cavity and the real-time pressure of the tire are the same, and when the pressure difference of the reference cavity and the monitoring cavity reaches a certain value, the elastic metal sheets are deformed to contact with the cathode of the battery, thus conducting the alarm circuit board. By adopting the monitoring device, the tire pressure can be known in real time, and pressure can be timely supplemented to the tire with low pressure, thus keeping good manipulability and safety performance of an automobile.

The invention provides a continuous variable quantum entanglement source generating device. The device comprises a laser module, a beam split coupling module, a laser reference cavity module, a phase modulator, an optical parametric amplifier locking module, an anti-phase regulating and locking module, an isolator and beam shaping module, an optical parametric amplifier module, a detection system module and a Bell state direct detection system module, wherein the modules are all fixed on each base plate, and after being subjected to sealing treatment, the modules are sequentially fixed at corresponding positions of an entanglement source total base plate, and a polysulfone cover covers nonlinear crystals in the optical parametric amplifier module for heat preservation. The entanglement source generating device is beneficial to improvement of stability, reliability, operability and exchangeability and is easy for productization, mass production, and the like.

A Micro-Electro-Mechanical System (MEMS) pressure sensor is disclosed, comprising a gauge wafer, comprising a micromachined structure comprising a membrane region and a pedestal region, wherein a first surface of the micromachined structure is configured to be exposed to a pressure medium that exerts a pressure resulting in a deflection of the membrane region. The gauge wafer also comprises a plurality of sensing elements patterned on the electrical insulation layer on a second surface in the membrane region, wherein a thermal expansion coefficient of the material of the sensing elements substantially matches with a thermal expansion coefficient of the material of the gauge wafer. The pressure sensor comprises a cap wafer coupled to the gauge wafer, which includes a recess on an inner surface of the cap wafer facing the gauge wafer that defines a sealed reference cavity that encloses and prevents exposure of the sensing elements to an external environment.

The invention discloses a low-permeability rock particle penetration rate measuring system and measuring method. The penetration rate measuring system comprises a high-pressure air source device, a reference cavity, a sample cavity, an inlet pressure intensity detecting device, an automatic valve, a ball valve, a pressure difference detecting device and a control device, wherein the automatic valve and the ball valve are sequentially arranged on a pipeline communicating the reference cavity and the sample cavity; the pressure difference detecting device and the automatic valve are connected in parallel; the control device is respectively connected with the automatic valve and the pressure difference detecting device; an output pipeline of the high-pressure air source device communicates with the reference cavity or the sample cavity; the inlet pressure intensity detecting device is arranged on the output pipeline of the high-pressure air source device; an air exhaust opening is formed in a pipeline of the inlet pressure intensity detecting device and the high-pressure air source device. The high-pressure air source device is connected with the reference cavity or the sample cavity; the change of the pressure intensity inside the reference cavity and the sample cavity can be controlled; the pressure intensity difference is detected through the pressure difference detecting device, so that the control device can accurately obtain a pressure intensity change curve and the particle penetration rate of rock to be measured.

The invention provides a permeability measurement system and method for low-permeability rock ore particles. The permeability measurement system comprises a high-pressure air source device, a reference cavity, a suction and exhaust valve and two symmetrically-arranged sample side devices; each sample side device comprises a sample cavity, an isolation valve and a balance valve, the sample cavity is communicated with the reference cavity through a circulation pipeline to receive high pressure air transmitted from the reference cavity; the isolation valve is arranged at the position of the circulation pipeline and close to the sample cavity; the balance valve is arranged at the position of the circulation pipeline and close to the reference cavity; the two sample cavities are respectively used for accommodating to-be-detected low-permeability rock ore particles and impermeable solids, the impermeable solids and the to-be-detected low-permeability rock ore particles are identical in particle size and volume, and the sample side devices are arranged at the same height. The permeability measurement system is simple and easy to maintain, small in dimension and high in safety; the permeability measurement system and method has the advantages that credibility and measurement precision of permeability of low-permeability rock ores are remarkably increased.

A gas detection system using a semiconductor laser with a reference gas cavity compensation is provided, said system comprising a first light source emitting a first beam of a first wavelength as a detection beam; a second light source emitting a second beam of a second wavelength, which is different from the first wavelength, as a reference beam; a first wavelength division multiplexer connected with said first light source and said second light source; a broadband coupler connected with said first wavelength division multiplexer; a reference gas chamber, which is introduced with reference gas of the same composition as that of the gas to be detected and of a known concentration; a detection gas chamber, which is introduced with the gas to be detected.

A semiconductor laser based intra-cavity optical micro-fluidic biosensor comprises a coupled-cavity semiconductor laser, a 2×2 coupler and a phase adjustment section on one input port of the coupler. The dominant mode of the coupled-cavity laser appears in one output port of the coupler, while the adjacent mode comes out from the other output port of the coupler. The resonant frequency interval of the sensing cavity is slightly larger or smaller than one half of that of the reference cavity. Part of the sensing cavity is the sensing section which is covered by an analyte. The refractive index change of the analyte will cause the lasing mode of the coupled cavity to switch to an adjacent mode, resulting in a π-phase change in the phase difference between the two output ports of the two resonance cavities. By applying the Vernier effect, the power ratio of the two output ports of the coupler will change and the refractive index change of the analyte can be derived. A detection limit of 10⁻⁸ RIU or smaller can be achieved.

The invention discloses a narrow-linewidth and long-time-stable frequency dye laser. The narrow-linewidth and long-time-stable frequency dye laser includes a reference-used laser generator, a dye laser, a reference cavity, a polarization beam splitter, a transmission cavity, a light detector, a data acquisition card, a processor, a signal adder and a function generator. According to the narrow-linewidth and long-time-stable frequency dye laser of the invention, two kinds of frequency stabilization methods are combined together to generate a narrow-linewidth and long-time-stable frequency laser beam, and the linewidth of the laser beam is 200kHz, and the frequency long-time drift of the laser beam is smaller than 2MHz. The narrow-linewidth and long-time-stable frequency dye laser of the invention has the advantages of simple circuit design, convenient realization and high scalability. The invention also provides a frequency stabilization method of the dye laser and is suitable for improving the long-time stability of the frequency of any dye lasers.

A system and method detect the presence of an unacceptable quantity of gas molecules in the reference vacuum cavity of a capacitance diaphragm gauge (CDG). An independent pressure transducer has an active portion exposed to the reference vacuum cavity. The transducer includes a ring anode, a cylindrical inner wall surface that forms at least one cathode, and a magnet positioned with respect to the ring anode such that the magnetic flux of the magnet is generally aligned with the central axis of the ring anode. A high voltage source applies a voltage between the ring anode and the cathode. A current sensor senses a magnitude of any current flowing between the ring anode and the cathode via ionized gas molecules. A monitoring unit monitors the magnitude of the current sensed by the current sensor and activates an alarm when the magnitude of the current exceeds an acceptable magnitude.

The invention provides a coronary artery load detecting system and a coronary artery load detecting method. The coronary artery load detecting method comprises the following steps: S1, acquiring the cross sectional area of a reference cavity, and acquiring voltage values of a main device at a position corresponding to the cross sectional area of the reference cavity under the lower frequency state and the high frequency state respectively; S2, acquiring the voltage values of the main device at positions of the bottom end or top end of a to-be-tested object under the lower frequency state and the high frequency state respectively under the same current; S3, driving the main device to move at uniform speed, and acquiring the voltage value of the main device in the movement process under the same current and under the lower frequency state; and S4, acquiring the cross sectional areas of all the positions of the to-be-tested object according to the preset fixed current value, the cross sectional area of the cavity, and the acquired voltage values. According to the system and the method, the voltage values of all the positions of the to-be-tested object are acquired through the frequency conversion manner, and further, the cross sectional areas of all the positions of the to-be-tested object are analyzed; and the parameters including the plaque parameters and the FFR of all the positions of the to-be-tested object are acquired according to the cross sectional areas, the operation and processing processes are greatly simplified, and the detection cost is reduced.

The invention relates to a seawater salinity detection device with a prism model capable of refracting for multiple times, which comprises an upper computer, a right-angle prism and a signal acquisition and processing module; optical glass which is perpendicular to an emitting light path of a laser and two pieces of optical glass which form a group of prism models in a mode of forming an acute angle alpha 1 and an obtuse angle beta 1 with the emitting light path of the laser are arranged below the laser and a position sensitive device, and two pieces of optical glass, which form a group of prism models and form an acute angle alpha 2 and an obtuse angle beta 2 with the opposite direction of the emitting light path of the laser respectively, are arranged above the right-angle prism sequentially; and the optical glass and a shell of the device enclose an upper closed reference cavity filled with reference liquid, and the optical glass and a shell at the bottom end of the device enclose a lower closed reference cavity which is provided with the right-angle prism and filled with the reference liquid. The seawater salinity detection device has a simple structure and is convenient to use, and due to the adoption of the prism models, the deflection angles of light rays are expanded, the resolution, accuracy and interference resistant capacity are improved, the length of the instrument is shortened, and the equipment cost and measuring cost are reduced.

The invention discloses a transmission cavity frequency stabilizing system and method for realizing long-term laser frequency stabilization and belongs to the field of precise laser frequency stabilization. The frequency stabilizing system mainly comprises a plurality of Ti-doped sapphire lasers, reference cavities, control boxes, a reference laser (helium-noon laser) with stable frequency, a polarization beam splitter, a Fabry-Perot transmission cavity, a photoelectric detector, a function signal generator, an adder, a data acquisition card, a computer and the like. The frequency stabilizing method comprises steps as follows: firstly, two Ti-doped sapphire lasers are locked on the respective reference cavities, and then the reference cavities are locked on the reference laser with stable frequency, so that two Ti-doped sapphire lasers with laser line width smaller than 100 kHz and long-term frequency drift smaller than plus/minus 1 MHz are obtained. The system and the method have the advantages that only one reference laser is used for locking the plurality of Ti-doped sapphire lasers with frequency to be stabilized simultaneously and can lock the Ti-doped sapphire lasers at any frequency within the tunable range, and the extensibility and the frequency stability are very high.

The invention discloses an automatic locking and relocking system of an ultra-stable laser device and a working method thereof. The system comprises an electro-optical modulator, a first wave plate, apolarization splitting prism, a second wave plate, an optical reference cavity, a monitoring unit, a photoelectric detector, an operation control unit, a frequency discrimination unit, a proportionalintegral control circuit (PI) and a voltage driver, wherein resonance is generated through the output frequency of the laser device and the optical reference cavity, parameters of the proportional-integral control circuit (PI) are adjusted through the operation control unit, so automatic locking of the ultra-stable laser device is realized, moreover, the monitoring unit is used for monitoring a locking state of the ultra-stable laser, so the unlocked laser device can be locked again. The system is advantaged in that the probability of successful locking of the laser device is improved, the time required by the locking process of the laser device is shortened, the locking quality of the laser device is guaranteed, and the commercialization and space application process of the ultra-stablelaser device is accelerated.

The design and manufacture method of a pressure sensor utilizing thermal field sensing with a thermal isolated membrane of a diaphragm structure is disclosed in the present invention. This device is made with silicon micromachining (a.k.a. MEMS, Micro Electro Mechanical Systems) process for applications of pressure measurement with large dynamic range, high accuracy and high stability during temperature variation. This device is applicable for all types of pressure metrology. The said thermal field pressure sensing device operates with thermistors on a membrane of the diaphragm structure made of silicon nitride with a heat isolation cavity underneath or a single side thermal isolated silicon nitride membrane with a reference cavity. This device can be seamlessly integrated with a thermal flow sensor with the same process.

The invention discloses a conveyable super-stable optical reference cavity for space application. The conveyable super-stable optical reference cavity comprises a globoid and a ring for fixing the globoid. The globoid is provided with a light through hole passing the center of the globoid, optical lenses are arranged at the two ends of the light through hole and made by utilizing an ultralow expanding material as a substrate material, and the globoid is further provided with a vacuum vent hole and a fixing hole. The ultralow expanding material is ULE, single crystal silicon, ceramic, microcrystalline glass or fused quartz. The conveyable super-stable optical reference cavity for space application is designed in a mode of combining a sphere and the ring. As shown in the background technology, the conveyable super-stable optical reference cavity for space application can well protect sphere space structural mechanics integrity, not only can achieve good vibration sensitivity in the three-dimensional direction, but also can meet the harsh conditions of space vibration impact and is simple to assemble and adjust on the whole.