145results about "Vacuum gauge using heat conductivity variation" patented technology

A vacuum gauge of the Pirani type for measuring the pressure of vaporized organic or inorganic material used in forming a layer of a device, comprising: an extended filament having a thickness of 5 microns or less and having a temperature coefficient of resistance greater than 0.0035/° C., the filament being subject to the vaporized organic or inorganic material; means for applying a current to the filament so that the temperature of the filament is less than 650° C. so as not to degrade the molecular structure of the organic material; and a structure responsive to a change in resistance or a change in current to determine heat loss from the filament, which is a function of the pressure of the vaporized organic or inorganic material.

A combination vacuum gauge provides simultaneous absolute and differential pressure measurements over a wide range of pressures ranging from atmospheric pressures to ultrahigh vacuum by processing the readings from an absolute high vacuum gauge (e.g., an ionization gauge and/or a heat-loss sensor), a differential low vacuum gauge providing a differential relative to ambient pressure (e.g., a diaphragm sensor), and a barometric absolute pressure sensor exposed to the ambient atmosphere outside the measurement region. The barometric absolute pressure sensor reading is used to convert the differential vacuum gauge reading from uncalibrated differential pressure to calibrated absolute pressure.

A microbolometer IR FPA is provided with in-situ vacuum sensing capability by realizing that the IR sensor microbolometer pixel element itself may be used as a vacuum sensor. The application of an electrical signal to the resistive element heats the bolometer material thereby producing a variable resistance related to vacuum level. The degree of variability for a given material depends on the efficiency of heat transfer from the material to the surrounding environment. In a good vacuum, heat transfer is poor, and thus heat will be retained in the material to produce a relatively large temperature increase and the resistance variability will be large. In a poor vacuum, heat is readily transferred to the environment and the temperature rise will be relatively small and thus resistance variability will be small. Consequently, the variable resistance magnitude can be readout to determine the vacuum level.

A method and apparatus for measuring gas pressure by combining an ionization gauge with at least one other vacuum sensor. Nonvolatile memory coupled to the vacuum gauge contains calibration parameters unique to each individual sensor based on factory calibration. The nonvolatile memory may contain calibration parameters for a heat-sensitive vacuum sensor to compensate for the temperature gradients generated by the ionization gauge. The calibration parameters are a function of calibration data determined when the ionization gauge is both on and off. The nonvolatile memory may store a window of measurement data of the vacuum gauge that is updated at predetermined time intervals and in response to an event, such as an error event, to aid in investigating the cause of vacuum gauge malfunction or failure.

A micro Pirani gage belongs to vacuum degree measuring element of micro electro mechanical system, aiming at overcoming the problems of large volume and not high enough sensibility of the existing micro Pirani gage. In the invention, a groove is arranged on a silicon substrate, a thermal isolation layer is arranged on the surface of the groove, an insulating layer is covered on the surface of the thermal isolation layer, a heating body is sputtered on the insulating layer, and the two ends of the heating body are sputtered with a metal electrode; wherein the heating body is made by platinum or nickel metal in bend shape; the insulating layer material is silicon nitride or silicon oxide; and the thermal isolation layer material is one or two of silicon oxide and silicon nitride. The invention has small volume, light weight and stable performance, the heating body adopts platinum metal, and the platinum metal has good linearity, stable performance, high sensibility and favourable chemical stability; and the invention has simple manufacturing technology, low cost, high yield and high reliability. The invention is applicable to vacuum degree real time detection in various vacuum encapsulation and micro cavities.

A method for sensing gas composition and gas pressure, based on the thermal constants of a variable electrical resistor, is presented. The method for sensing gas composition and pressure includes monitoring a variable electrical resistor whose dynamic thermal response is determined by the thermal conductivity and thermal capacity of the surrounding gas of a given atmospheric environment. In the thermal domain, the sensor has a low-pass characteristic, whose phase delay is determined by the thermodynamic characteristics of the surrounding gas such as composition and pressure. The method can be used for sensing gas composition and can also be used for sensing gas pressure.

An electron-emitting cathode consists of an electrically conducting emitter layer attached to a side wall which consists of stainless steel and a gate which is fixed at a mall distance inside a concave emitter surface of the emitter layer. The cathode surrounds a reaction area containing a cylindrical grid-like anode and a central ion collector which consists of a straight axial filament. An ion collector current reflecting the density of the gas in the reaction region is measured by a current meter while a gate voltage is kept between the ground voltage of the emitter layer and a higher anode voltage and is regulated in such a way that an anode current is kept constant. The emitter layer may consists of carbon nanotubes, diamond-like carbon, a metal or a mixture of metals or a semiconductor material, e.g., silicon which may be coated, e.g., with carbide or molybdenum. The emitter surface can, however, also be a portion of the inside surface of the side wall roughened by, e.g., chemical etching. The gate may be a grid or it may be made up of patches of metal film covering spacers distributed over the emitter area or a metal film covering an electron permeable layer placed on the emitter surface.

The invention provides a three-dimensional vacuum sensor and a manufacturing method of the three-dimensional vacuum sensor. A thermo-electric pile and a heater manufactured by adopting the method are located on different planes, and the thermo-electric pile is arranged on the heater, thus the miniaturization of the thermo-electric vacuum sensor can be further implemented. The shorter vertical distance between the micro heater to a substrate can be obtained by adopting a dry etching release structure through controlling the etching opening and the etching time, the pressure measurement upper limit of a heat conducting vacuum gauge can be improved, the problem of adhesion of a structural layer and the substrate can be avoided, and the rate of finished production of the devices can be improved. Due to the additional arrangement of a silicon cover plate, the thermal conductivity of the gas can be enhanced, and the sensitivity of the heat conducting vacuum gauge on the higher gas pressure end can be improved. In addition, the materials of the semiconductor substrate, the thermo-electric pile and the micro-heater and the preparation technology adopted in the invention are commonly used in the semiconductor process and can be easily compatible with the existing CMOS (complementary metal oxide semiconductor) process.

The invention discloses a vacuum degree on-line detecting system which comprises a display module, a data collection terminal, a vacuum degree on-line detecting module and a vacuum on-line detecting sealing plug, wherein the vacuum on-line detecting sealing plug is used for obtaining vacuum data of vacuum equipment, the vacuum degree on-line detecting module is used for processing the vacuum data obtained by the vacuum on-line detecting sealing plug so that the vacuum degree of a vacuum layer of the vacuum equipment is obtained, and the data collecting terminal is used for obtaining vacuum degree data which is sent by at least one vacuum degree on-line detecting module and conducting alarm notification and / or outputting a signal which can control the vacuum equipment to be shut down according to a comparing result of the vacuum degree data and the preset vacuum degree parameter. The vacuum degree on-line detecting system has the advantages of achieving on-line detection of the vacuum degree of the vacuum equipment, detecting a plurality of targets, effectively playing a role in preventing safety hazard, reducing the rate of vacuum leaking and accidents of the equipment, and guaranteeing the using safety.

A miniature thermal conductivity gauge employs a carbon single-walled-nanotube. The gauge operates on the principle of thermal exchange between the voltage-biased nanotube and the surrounding gas at low levels of power and low temperatures to measure vacuum across a wide dynamic range. The gauge includes two terminals, a source of constant voltage to the terminals, a single-walled carbon nanotube between the terminals, a calibration of measured conductance of the nanotube to magnitudes of surrounding vacuum and a current meter in electrical communication with the source of constant voltage. Employment of the nanotube for measuring vacuum includes calibrating the electrical conductance of the nanotube to magnitudes of vacuum, exposing the nanotube to a vacuum, applying a constant voltage across the nanotube, measuring the electrical conductance of the nanotube in the vacuum with the constant voltage applied and converting the measured electrical conductance to the corresponding calibrated magnitude of vacuum using the calibration. The nanotube may be suspended to minimize heat dissipation through the substrate, increasing sensitivity at even tower pressures.

Method and apparatus for measuring the pressure of a fluid medium, by immersing within the fluid medium an electrical resistor having a resistance varying with temperature; applying electrical current through the electrical resistor to heat it to a predetermined temperature above that of the fluid medium; and measuring the rate of change in resistance of the electrical resistor to produce a measurement of the rate of thermal heat dissipation, varying with the density of the fluid medium in which the electrical resistor is immersed, and thereby a measurement of the pressure of the fluid medium. The electrical resistor is a positive temperature coefficient thermistor driven by a constant voltage source and having a resistance which increases sharply at the predetermined temperature, such that the thermistor is automatically self-controlled to substantially maintain the predetermined temperature, whereby the electrical current drawn by the thermistor is a measurement of the thermal load on the thermistor resulting from the thermal heat dissipation therefrom, and thereby a measurement of the pressure of the fluid medium. Many applications of such method and apparatus are described, including a vacuum gauge, a pressure gauge, a barometer, a Pitot tube type speedometer, and a helicopter blade leak detector.

The invention provides a three-dimensional vacuum sensor and a preparation method of the three-dimensional vacuum sensor, wherein a thermopile and a heater prepared by the method are located on different planes; the thermopile is located below the heater to further implement miniaturization of a thermoelectric vacuum sensor; a dry etching release structure is utilized to avoid a problem that a structural layer is adhered with a substrate in a wet etching release process, and the yield of devices is improved; a silicon cover board is additionally arranged, that is, gas heat conduction between the cover board and the heater is increased so as to be beneficial to improving sensitivity of a thermal radiation vacuum gauge on an end with higher pressure intensity. In additional, the materials and the preparation process of the semiconductor substrate, the thermopile and the micro heater are all frequently used in the semiconductor process, so the three-dimensional vacuum sensor is easily compatible with an existing CMOS (complementary metal oxide semiconductor) process.

A capped microsensor is described. It is suggested that a current conductor, positioned in the cavity and having at least two voltage taps, be provided, this configuration being used for seal testing, e.g., during quality control, by detecting at least one thermodynamic variable of a gaseous medium present inside the cavity via this configuration.

An interoperable vacuum measuring device is presented, which automatically adjusts to one of two or more vacuum sensors having different electrical characteristics. The interoperable vacuum measuring device in a first step detects which type of vacuum sensor it is connected to. In a second step it controls and evaluates the vacuum sensor, using control parameters determined in response to the detection of the first step.

Detection of a vacuum sensor type is achieved by measuring the electrical resistance between any two pins of a vacuum sensor's connector and comparing the measured resistance values with stored resistance values of known vacuum sensors.

Further, a vacuum measuring device is presented, which automatically identifies a vacuum sensor, and associates a vacuum pressure measurement with a vacuum sensor. The identification of a vacuum sensor is facilitated by an identification disk, which is placed onto and operatively connected to the male terminals of a vacuum sensor's connector.

A heat conduction type barometric sensor has high sensitivity and high accuracy that has simple structure and circuit configuration and can measure a barometric pressure in the range of a very low barometric pressure to ≧1 atm using one sensor chip. The sensor includes a cantilever-shaped thin film provided with a thin-film temperature sensor, a heating element, and an excitation element. The excitation element utilizes warpage and bending based on a difference in thermal expansion between two main layers constituting the thin film during intermittent heating by a thin-film heater as the heating element. The two main layers are a silicon layer and a thermally oxidized film of silicon which are significantly different from each other in the coefficient of thermal expansion. A circuit in which the sensitivity is enhanced by the integration of a seebeck current for a predetermined period of time can be also provided.

A tightness testing method for a MEMS or small encapsulated component, the MEMS or small component being housed in a cavity of a carrier. The cavity being sealed and containing a gas having a different density to the density it would have if subjected to the pressure of the medium outside the cavity. The method measures the density of the gas contained in the cavity.