Abstract:
The invention relates to a radiation source which comprises: a support (400) provided with a wall (410); a membrane (200) comprising two faces, the membrane (200) being adapted to emit an infrared radiation according to one and the other of its faces, and maintained in suspension with respect to the support (400), the rear face (220) in line with and at a distance D from the wall (410); electrostatic actuating means (300) adapted to vary the distance D; the membrane (200) and the means (300) being laid out such that, for each wavelength, the infrared radiation emitted by the rear face (220) is reflected by the wall (410), passes through the membrane (200) and interferes with the infrared radiation emitted by the front face (210).
Abstract:
A light emitter device includes an emitter component including a heater structure arranged on a membrane structure. The membrane structure is located above a first cavity. Additionally, the first cavity is located between the membrane structure and at least a portion of a supporting substrate of the emitter component. Further, the heater structure is configured to emit light, if a predefined current flows through the heater structure. Additionally, the light emitter device includes a lid substrate having a recess. The lid substrate is attached to the emitter component so that the recess forms a second cavity between the membrane structure and the lid substrate. Further, a pressure in the second cavity is less than 100 mbar.
Abstract:
A light source and a method for its use in an optical sensor are provided, the light source including a resistively heated element. The light source includes a power circuit configured to provide a pulse width modulated voltage to the resistively heated element, the pulse width modulated voltage including: a duty cycle with a first voltage; and a pulse period including a period with a second voltage, wherein: the duty cycle, the first voltage, and the pulse period are selected so that the resistively heated element is heated to a first temperature; and the first temperature is selected to emit black body radiation in a continuum spectral range. Also provided is an optical sensor for determining a chemical composition including a light source as above.
Abstract:
A light source and a method for its use in an optical sensor are provided, the light source including a resistively heated element. The light source includes a power circuit configured to provide a pulse width modulated voltage to the resistively heated element, the pulse width modulated voltage including: a duty cycle with a first voltage; and a pulse period including a period with a second voltage, wherein: the duty cycle, the first voltage, and the pulse period are selected so that the resistively heated element is heated to a first temperature; and the first temperature is selected to emit black body radiation in a continuum spectral range. Also provided is an optical sensor for determining a chemical composition including a light source as above.
Abstract:
A light source and a method for its use in an optical sensor are provided, the light source including a resistively heated element. The light source includes a power circuit configured to provide a pulse width modulated voltage to the resistively heated element, the pulse width modulated voltage including: a duty cycle with a first voltage; and a pulse period including a period with a second voltage, wherein: the duty cycle, the first voltage, and the pulse period are selected so that the resistively heated element is heated to a first temperature; and the first temperature is selected to emit black body radiation in a continuum spectral range. Also provided is an optical sensor for determining a chemical composition including a light source as above.
Abstract:
A system for the detection and analysis of at least one volatile substance in breath samples of a subject, including at least one source of infrared radiation adapted to the wavelength range of specific absorption peaks of said substances, a plurality of reflecting surfaces of said radiation adapted for collimation onto at least one detector providing a plurality of electrical output signals corresponding to the transmission of said radiation within wavelength intervals corresponding to said absorption peaks, at least one measuring cell including a mechanical support structure defining the position of said source, reflecting surfaces and detector, adapted to the reception and disposal of said breath sample, and exposing it to said radiation, at least one electronic signal processing unit with capacity to analyse said signals with respect to pre-programmed information concerning infrared absorption spectra of said substances. The response of the system being displayed or otherwise communicated, and perceived as essentially instantaneous.
Abstract:
Thermally tunable optical sensors are used in sampling tools for analysis of samples from a wellbore. The thermally tunable optical sensors generate a series passbands of wavelength emissions and detect attenuation in a signal thereof. The attenuation detected is processed and used to determine aspects of the samples. Analysis may be completed remotely (outside of the wellbore), within the wellbore (during drilling or otherwise), or as a part of another process such as fluid management, transport and refinement.
Abstract:
Pulsating infrared radiation source 50, which is so thin as to make its thermally stored energy less than the energy radiated during each pulse. This makes the source cooled by its own heat emission. Such sources have thicknesses commensurate with the wavelengths of infrared radiation. To avoid interference effects, the source's optical thickness may be made to equal a multiple of half wavelengths of the desired radiation. With the source mounted in a housing 53, efficient radiative cooling is obtained using windows 54 and 55 to each side. This makes it possible to extract infrared radiation from either face of the source.
Abstract:
A system for detecting fires uses at least two carbon dioxide sensors positioned at spaced locations in a room. Each sensor produces an electrical output signal representative of the carbon dioxide concentration in its vicinity. A computer calculates the ratio of the concentration sensed by each sensor to the concentration sensed by each of the other sensors, and any imbalance in the distribution of carbon dioxide will be reflected in these ratios. Random variations prevent the ratios from being equal, and the magnitude of the random variations is quantized by calculating the standard deviation of the ratios. The ratios are then normalized and compared to a threshold level that corresponds to a chosen false alarm rate.
Abstract:
A sample chamber for use in measuring the absorption of radiation as it passes through a gas within the chamber includes a block having an extended serpentine passage through it. The walls of the extended passage are coated with a highly reflective material so that the extended passage acts as a light pipe for transmitting the radiation. A number of smaller passages permit gases in the space surrounding the sample chamber to diffuse into the extended passage through which the radiation is conducted. The sampling chamber is made by joining two halves, each of which has a planar face in which an elongated groove is produced. The halves are molded of plastic and in quantity the chamber is quite inexpensive.