Abstract: A propeller formed along the lines of a vortex, i.e. a Fibonacci spiral projected onto a surface formed by a square hyperbola. Fluid flows evenly along the length of the propeller with less turbulence allowing it to operate at a higher pitch without stalling and resulting in reduced power requirements for a given flow rate. The underlying geometric shape of a vortex is an equiangular logarithmic spiral also known as golden spiral or Fibonacci spiral as is often found in natural objects ranging from sea shells to spiral galaxies. When viewed three dimensionally, the fluid flow in a vortex can be drawn as a projection of a golden spiral onto a surface of revolution of a square hyperbola where the vertex is equal to one and the focus is equal to the square root of 2.

Abstract: A method of manufacturing a detector capable of detecting a wavelength range [?8; ?14] centered on a wavelength ?10, including: forming said device on a substrate by depositing a sacrificial layer totally embedding said device; forming, on the sacrificial layer, a cap including first, second, and third optical structures transparent in said range [?8; ?14], the second and third optical structures having equivalent refraction indexes at wavelength ?10 respectively greater than or equal to 3.4 and smaller than or equal to 2.3; forming a vent of access to the sacrificial layer through a portion of the cap, and then applying, through the vent, an etching to totally remove the sacrificial layer.

Abstract: A method of manufacturing a detector capable of detecting a wavelength range [?8; ?14] centered on a wavelength ?10, including: forming said device on a substrate by depositing a sacrificial layer totally embedding said device; forming, on the sacrificial layer, a cap including first, second, and third optical structures transparent in said range [?8; ?14], the second and third optical structures having equivalent refraction indexes at wavelength ?10 respectively greater than or equal to 3.4 and smaller than or equal to 2.3; forming a vent of access to the sacrificial layer through a portion of the cap, and then applying, through the vent, an etching to totally remove the sacrificial layer.

Abstract: A method of assembling and hermetically sealing a package including a side wall mounted on a substrate, with the space thus defined accommodating a component that operates in a controlled atmosphere, the space being closed off by a hermetic sealing cover mounted on said side wall. This method involves depositing a metallic connector element, also referred to as a brazing preform, on the upper face of the side wall; depositing the upper cover on, and in contact with, the brazing preform; subjecting the assembly thus obtained to the desired environment in terms of the kind of gas and operating pressure of the component; increasing the temperature to a value that is at least in excess of the melting temperature of the material that constitutes the brazing preform; then lowering said temperature in order to cause solidification of said brazing material and, consequently, sealing of the cover on the side wall.

Abstract: An infrared radiation detection device comprising: a substrate; a matrix of at least one line of elements for detecting the radiation, each comprising a resistive imaging bolometer, the matrix being formed above the substrate; a bolometer reading circuit, a temperature measuring device for measuring the temperature in at least one point of the substrate; and a compensation circuit and data processing device for correcting the signal formed from each bolometer as a function of the temperature measured in at least one point of the substrate. The compensation circuit and data processing device capable of correcting the signal formed from the imaging bolometer by using a predetermined physical model of the temperature behavior of the signal.

Abstract: A device for detecting infrared radiation comprising an array of bolometers for detecting radiation; and in order to read each bolometer, a signal shaping circuitry comprising: a circuitry capable of biasing the bolometer at a predetermined voltage in order to make current flow therethrough; a circuitry capable of generating a common-mode current; and a circuitry capable of integrating the difference between the current that flows through the bolometer and the common-mode current. According to the invention, the device comprises a circuitry capable of injecting current into each bolometer in order to shift its resistance by a predetermined quantity that depends on its offset, current injection being performed prior to readout biasing of the bolometer and the shift being performed according to the direction in which the bolometer's resistance varies as a function of temperature. In addition, correction circuitry is capable of shifting the resistances of bolometers towards a common value.

Abstract: The invention relates to a device for detecting electromagnetic radiation comprising: a resistive bolometer, a biasing circuit capable of biasing said bolometer with a predetermined bias voltage, a rejection module capable of generating a common mode current, a measuring circuit capable of being connected to a bolometer and a rejection module in order to measure the difference between the current flowing through the bolometer when it is biased and the common mode current generated by the rejection module. According to the invention, rejection module comprises: a module for estimating a current that flows through resistive bolometer when it is subjected to the bias voltage and made insensitive to the electromagnetic radiation; and a current generator which is controlled by the estimation module and generates the current estimated by the latter as a common mode current.

Abstract: An infrared radiation detection device comprising: a substrate; a matrix of at least one line of elements for detecting said radiation, each comprising a resistive imaging bolometer, said matrix being formed above the substrate; means for reading the bolometers of the matrix, means for measuring the temperature in at least one point of the substrate; and means for correcting the signal formed from each bolometer as a function of the temperature measured in at least one point of the substrate. The correcting means are capable of correcting the signal formed from the imaging bolometer by means of a predetermined physical model of the temperature behaviour of said signal.

Abstract: A device for detecting infrared radiation including a matrix of resistive imaging bolometers above a substrate, a read circuit forming an analog electrical signal constituting an image of the infrared radiation impinging on the matrix, a probe for measuring the temperature of the substrate, an ADC for converting the analogue electrical signals from the read circuit and probe, and a data processing unit for correcting the signal formed by the read circuit according digital values NC(i,j) corresponding to electrical signals from the bolometers exposed to a uniform scene at the measured temperature of the substrate. The data processing unit including a unit for computing the digital values NC(i,j) based on a single set of parameters of a predetermined physical model of the read circuit electrical signals and corresponding to the exposure of the matrix of imaging bolometers to a temperature substantially equal to the measured substrate temperature.

Abstract: A device for detecting infrared radiation comprising an array of bolometers for detecting radiation; and in order to read each bolometer, a signal shaping circuitry comprising: a circuitry capable of biasing the bolometer at a predetermined voltage in order to make current flow therethrough; a circuitry capable of generating a common-mode current; and a circuitry capable of integrating the difference between the current that flows through the bolometer and the common-mode current. According to the invention, the device comprises a circuitry capable of injecting current into each bolometer in order to shift its resistance by a predetermined quantity that depends on its offset, current injection being performed prior to readout biasing of the bolometer and the shift being performed according to the direction in which the bolometer's resistance varies as a function of temperature. In addition, correction circuitry is capable of shifting the resistances of bolometers towards a common value.

Abstract: A device for detecting infrared radiation comprising an array of bolometric detectors which are sensitive to incident radiation and are referred to as “active” and a bolometer which is insensitive to said radiation and is referred to as “blind” formed on a substrate in which a read circuit is produced for sequentially addressing each of the rows of detectors of the array, each of the active bolometers in a single row being biased simultaneously. The read circuit also comprises means of producing a reference current (Iref) based on the blind bolometer; means of simultaneously copying the reference current (Iref) for each column of the array; and a plurality of current integrators, each associated with one column of the array and each designed to integrate the difference between the current flowing through the active bolometer of the row which is currently being read and said thus copied reference current.

Abstract: An infrared radiation detection device comprising: a substrate; a matrix of at least one line of elements for detecting said radiation, each comprising a resistive imaging bolometer, said matrix being formed above the substrate; means for reading the bolometers of the matrix, means for measuring the temperature in at least one point of the substrate; and means for correcting the signal formed from each bolometer as a function of the temperature measured in at least one point of the substrate. The correcting means are capable of correcting the signal formed from the imaging bolometer by means of a predetermined physical model of the temperature behaviour of said signal.

Abstract: The invention relates to a passive microbolometer (12), comprising a reflective screen (17) and a suspended membrane with the function of radiation absorber, thermometer and electrical connection. The membrane is supported by at least two anchor elements (15) fixed to a support substrate (16). The reflective screen (17) may be embodied by at least one layer (18) of metallic material with a thickness of the order of 500 ? to 2000 ?. The screen (17) is arranged beneath the membrane in electrical contact with the membrane absorber element (13) such as to reduce the area resistance of the unit made up of the screen (17) and the absorbing element (13) and to avoid the absorption of radiation by the latter.

Abstract: An infrared detection device including a matrix of bolometric detectors electrically connected to a reading circuit. Each of the detectors includes at least two electrically conductive thermal insulation structures insulated from one another and fitted in contact at one of their ends with an active zone consisting of a bolometric material. One of the structures is electrically connected at its other end to the reading circuit by a cold electrical connection that is kept at a substantially constant potential. The other structure is electrically connected at its other end to the reading circuit by a hot electrical connection, which is connected in series with a switch integrated into the reading circuit. At least two adjacent bolometric detectors are connected by a common electrical connection to the substantially constant potential of the reading circuit.

Abstract: A bolometric detector including a sensitive part having one or more layers of a sensitive material, the resistivity of which varies with temperature, electrodes isolated from one another, also acting as infrared radiation absorbers, the electrodes being in contact with the sensitive material over at least part of their surface, at least one support region for supporting the sensitive part, acting so as to position the sensitive part, and acting as an electrical conductor, in relation to a read circuit associated with the bolometric detector, and at least one thermal insulation structure electrically and mechanically connecting each support region to the sensitive part. The regions of sensitive material not in contact with the electrodes have at least one corrugation oriented along the direction perpendicular to the plane containing the sensitive part of the bolometric detector.

Abstract: An infrared detection device including a matrix of bolometric detectors electrically connected to a reading circuit. Each of the detectors includes at least two electrically conductive thermal insulation structures insulated from one another and fitted in contact at one of their ends with an active zone consisting of a bolometric material. One of the structures is electrically connected at its other end to the reading circuit by a cold electrical connection that is kept at a substantially constant potential. The other structure is electrically connected at its other end to the reading circuit by a hot electrical connection, which is connected in series with a switch integrated into the reading circuit. At least two adjacent bolometric detectors are connected by a common electrical connection to the substantially constant potential of the reading circuit.

Abstract: A bolometric detector including a sensitive part having one or more layers of a sensitive material, the resistivity of which varies with temperature, electrodes isolated from one another, also acting as infrared radiation absorbers, the electrodes being in contact with the sensitive material over at least part of their surface, at least one support region for supporting the sensitive part, acting so as to position the sensitive part, and acting as an electrical conductor, in relation to a read circuit associated with the bolometric detector, and at least one thermal insulation structure electrically and mechanically connecting each support region to the sensitive part. The regions of sensitive material not in contact with the electrodes have at least one corrugation oriented along the direction perpendicular to the plane containing the sensitive part of the bolometric detector.

Abstract: The thread (15) of a wood or the like screw has pairs of V-shaped recesses (22, 23) in the edge of a selected intermediate length of the thread (17). Each pair defines a W-shaped cutout (19, 20, 11). The cutouts (19-21) extend into only a part of radial width of the thread (15). There are only about five cutouts (19-21) at each convolute (17) of the limited length. The lengths of the thread portion (16) at the tip and the thread portion (18) at the head (13) of the screw are devoid of the cutouts. Each cutout defines a cutting tooth (24) which facilitates the driving of the screw into the workpiece. The recesses (22, 23) provide cavities for fibrous debris generated by the respective tooth (24). When the screw is in place, the teeth (24) are pressed axially toward the thread produced in the workpiece to reduce the loosening tendency of the installed screw. The disposition and size of the cutouts (19-21), is about three cutouts per one convolute so as not to unduly impede the torque strength of the screw.

Abstract: In a method and apparatus for regenerating a primary cell, voltage pulses of a predetermined amplitude and a predetermined duration in the range of 10.sup.-3 to 2.times.10.sup.-3 seconds are applied to the primary cell at a frequency of 2 Hz to 200 Hz whereby primary cells which cannot be recharged can be reconditioned for a greatly extended life. The apparatus includes a switching device with a low voltage input connected to a low resistance DC voltage source, an output delivering a sequence of voltage pulses to a primary cell, and a timing generator for timing the switching device.