Abstract:
A sensor (14) having a nanotube (15) grown on and supported by thermal bimorph structures (11, 12). The nanotube (15) rests on a heat sink (13) during sensing gas or a liquid and is moved from the heat sink when the nanotube is heated to desorb gas or liquid from it. The heatsink (13) may function as a gate along with the bimorph structures (11, 12) as the other terminals of a transistor. Current-voltage and current-gate voltage characteristics may be obtained of the nanotube as a device like a transistor. These characteristics may provide information on a gas or liquid absorbed by the nanotube.
Abstract:
Infrared scene projectors are useful in testing infrared surveillance and guidance equipment which identify and track objects, such as enemy missiles, based on their infrared emissions or heat-generation characteristics. Infrared scene projectors typically include a thermal or infrared image. One problem with conventional thermal pixel arrays is that each pixel has a unique ground voltage based on its point of connection to a ground terminal running through the array, making it difficult to precisely control the pixels. Accordingly, the present inventors devised not only innovative infrared pixel arrays and related control methods, but also infrared scene projectors incorporating them. In one exemplary pixed array, each pixel includes a resistor and a current-mirror circuit which enables control. Operating the array entails receiving a pixel-control voltage, converting the pixel-control voltage to a current, and then coupling the current to the current-mirror circuit in one or the pixels. The current mirror applies an appropriate control current to the resistor and thus enables operation of the pixedl independent of ground-voltage variations.
Abstract:
A system having a flow channel for conveying a sample and having fluid light guides for projecting light to the sample target area and collecting light from the sample target area. The system may have fluid light guides on or off the card containing the flow channel. Accurate alignment may be provided by the fluid light guides in lieu of requiring precise alignment for the light source and detectors. The flow channel may be a part of a cytometer system.
Abstract:
A microcathode which integrates both an electron emitter, or cathode, and an extractor electrode. The electron emitter is attached to the back side of a thin film microstructure on a first surface of a substrate. Electrons are emitted from the electron emitter and into a via extending through the substrate. An electron beam is formed which is pulled through the via and out of the microcathode by an extractor electrode on a second surface of the substrate. The extractor electrode modulates the electron beam current, defines the beam profile, and accelerates the electrons toward an anode located outside of the microcathode. Microcathode of this invention are particularly suitable as electron emitting devices useful for various types of electron beam utilizing equipment such as flat cathode ray tube displays, microelectronic vacuum tube amplifiers, electron beam exposure devices and the like.
Abstract:
A microbolometer array has pixels with a thin platform of silicon dioxide having a metal absorber layer, and having a resonant gap with a substrate reflector. The pixel resistor of vanadium oxide has low total resistance with metal contacts on opposite edges.
Abstract:
A system for detecting a flame. The system may discriminate between a detected hot object and flame. The system may be a camera-like structure incorporating an infrared sensor, a lens, and an element that could filter out some of the long-wave infrared radiation. The sensor may receive radiation of a scene which forms images on the sensor. The images may be provided to a processor that incorporates one or more modules to determine whether a flame is present in the scene.
Abstract:
The invention is a method and apparatus capable of detecting constituents of a gas at extremely low concentrations comprising providing a medium that is absorbent of at least a first particular gas under a first environmental condition and desorbent of the particular gas under a second environmental condition, exposing the medium to a sample gas for a first period of time under the first environmental condition, during a second period of time after the first period of time, exposing the medium to the second environmental condition to cause the medium to desorb gas into an optical cavity of a cavity ring down spectrometer and introducing electromagnetic radiation into the cavity, during a third period of time after the second period of time, ceasing introduction of the electromagnetic radiation into the cavity and detecting the decay of the electromagnetic radiation in the cavity, and analyzing the decay of the light in the cavity to obtain a spectral analysis of the sample gas.
Abstract:
A low power gas sensor is provided for detecting one or more gases in a gas sample. The gas sensor includes a sensor for sensing a desired gas and a heater for heating the sensor. During operation, a controller provides power to the heater to heat the sensor to an operating temperature during a first period of time. Once at the operating temperature, the controller may read the sensor to determine a measure of the detected gas in the gas sample. Once a measurement is taken, and to conserve power, the controller removes the power to the heater allowing the heater and sensor to cool to at or near the ambient temperature for a second period of time. The second to period of time may be longer than the first period of time, and in some cases, substantially longer. In some embodiments, the sensor and heater may be thermally isolated from some or all of the remainder of the gas sensor, such as the sensor substrate. This may also help reduce the amount of power that is required to heat the heater and sensor to the operating temperature. The gas sensor of the present invention may be ideally suited for battery powered and/or wireless applications.
Abstract:
An infrared detector has a window in a cover having a cavity for exposing detector pixels to incident radiation. The window has an antireflective element formed within the cavity as a field of posts. The field of post structures is formed in a cavity by etching the posts in a desired pattern first, and forming the cavity by a general etch over the whole field afterward.
Abstract:
Heavier noble gases such as xenon and argon can reduce the run-in period for vacuum tubes and in particular flame detector tubes. The tubes can be filled with a run-in gas and then run-in. The run-in gas can then be exchanged for an end gas, such as neon, and the tube sealed. A final conditioning step of running in the tube with the end gas can further smooth the tube's anode and cathode to thereby improve performance and operating life.