Chemical vapor sensor
First Claim
1. A chemical vapor sensor comprising:
- an infrared source for generating infrared waves;
an infrared detector for measuring the intensity of the infrared waves generated from the infrared source; and
a vapor concentrator including a vapor adsorber and a heating source to heat the vapor adsorber, for transferring concentrated vapor into a path of the infrared waves.
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Accused Products
Abstract
A chemical vapor sensor is provided that passively measures a chemical species of interest with high sensitivity and chemical specificity. In an aspect, ethanol vapor in a vehicle cabin is measured, and sufficient sensitivity is provided to passively detect a motor vehicle driver that exceeds a legal limit of blood alcohol concentration (BAC), for use with vehicle safety systems. The sensor can be situated in an inconspicuous vehicle cabin location and operate independently without requiring active involvement by a driver. A vapor concentrator is utilized to amplify a sampled vapor concentration to a detectible level for use with an infrared (IR) detector. In an aspect, in comparison to conventional chemical sensors, the sensitivity of detection of ethanol vapor is increased by a factor of about 1,000. Further, a single channel of infrared detection is utilized avoiding spurious infrared absorption and making the chemical vapor sensor less costly to implement.
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Citations
22 Claims
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1. A chemical vapor sensor comprising:
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an infrared source for generating infrared waves;
an infrared detector for measuring the intensity of the infrared waves generated from the infrared source; and
a vapor concentrator including a vapor adsorber and a heating source to heat the vapor adsorber, for transferring concentrated vapor into a path of the infrared waves. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A passive chemical vapor sensor for sampling ethanol vapor from a vehicle cabin comprising:
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an infrared source for generating infrared waves;
an infrared detector for measuring the intensity of the infrared waves generated from the infrared source;
an infrared filter for selecting a range of infrared frequency or wavelength that is adsorbed by a predetermined chemical species of interest;
an infrared absorption cell defining an inlet for taking in air, and an outlet for expelling air;
a vapor concentrator including a vapor adsorber and a heating source to heat the vapor adsorber, for transferring concentrated vapor into a path of the infrared waves; and
an air flow source for controlling air flow through the vapor adsorber and through the infrared absorption cell. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method of measuring a chemical vapor concentration comprising:
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passing air, including sample vapor, through an adsorber;
measuring an output (designated Voff) of an infrared detector, with an infrared source deactivated;
heating the adsorber;
measuring an output (designated Von) of the infrared detector, with the infrared source activated;
passing concentrated sample vapor from the adsorber into and through the infrared absorption cell at a predetermined time;
measuring a change in an output (designated Vsig) of the infrared detector; and
calculating the ratio Vsig/(Von−
Voff). - View Dependent Claims (17, 18, 19, 20, 21, 22)
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Specification