Optics: measuring and testing – For light transmission or absorption
Patent
1998-04-22
2000-01-18
Font, Frank G.
Optics: measuring and testing
For light transmission or absorption
356437, 356442, G01N 2100
Patent
active
060162031
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a gas cell and/or to a gas sensor.
By gas cell we mean a cavity in which a gas sample exists, which gas sample is penetrated by a beam of light or by rays of light, to enable an analysis of the gas structure and concentration by means of the change of the spectrum of the penetrating beam of light, by means of a light source and/or a light detector, which are positioned outside of the cavity, or the unit in which the cavity is formed.
If the unit is permitted to contain said light source, light detector, and/or circuits for evaluating gas structures and/or gas concentrations, then it is called a gas sensor.
For the sake of simplicity, the description that follows and the Claims section use the expression gas sensor for both types of design.
In particular, the present invention relates to a gas sensor that is designed to enable a measurement of a gas sample enclosed in a cavity.
According to the invention, the design of the gas sensor comprises a block, which contains a cavity that serves as a gas cell. As relates to light, the wall or wall sections of the cavity exhibit highly-reflective properties.
Said cavity contains means, such as an opening or section for incoming rays of light or light, and means, such as an opening or section for rays of light or light to be received within or exit the cavity after the light has been reflected one or more times inside the cavity.
In particular, the present invention provides a gas sensor, which is part of a system wherein a gas and/or a portion of gas in a gas sample is analysed with respect to the gas itself and/or to the proportional share (concentration) of the gas in the sample, using an absorption spectrum, which appears in the light spectrum of the exiting light.
To better understand the present invention and its characteristics, we are required to use expressions such as directly-reflected light beam or rays of light, and indirectly-reflected light beam or rays of light.
By directly-reflected light beam or rays of light we mean that a beam of light may pass through the cavity without reflecting in the cavity's delimiting parallel surface sections, except in a mirror surface opposite the beam of light, which reflects the beam of light in the same plane, but in a different direction.
By indirectly-reflected light beam or rays of light we mean that a beam of light may pass through the cavity reflecting one or more times in the mirror structure of the cavity's delimiting surface sections.
BACKGROUND ART
Gas sensors of the kind described above exist in various different embodiments.
These kinds of gas sensors have a cavity or space that functions as a gas cell through which rays of light are allowed to pass. Interacting with the gas cell are light emitting means and light receiving means (light receiver). The light receiver is designed to enable an evaluation of the current lines of absorption in the light spectrum for an exiting beam of light, or rays of light.
Within the cavity, between the light emitting means and the light receiver in the gas cell, is a light path, hereafter called a measuring path or optical measuring path.
In optical applications the terms "geometrical path" and "optical path" are sometimes used, where the geometrical path is a geometrical distance and the optical path is a geometrical distance multiplied with the refractive index of the medium through which the light passes. In so called "standard air", where the refractive index is 1, the optical path is thus equal to the geometrical path.
The terms "measuring path" and "optical measuring path" are used synonymously in this description since the gas concentrations at hand are very low which gives a refractive index very close to 1.
Even if the refractive index would deviate substantially from 1, for example at a measurement of a fluid, these terms could be used synonymously since the used technique is based on reflections of light in a homogeneous medium and not on transmissions of light through various mediums with different refractive i
REFERENCES:
patent: 4756622 (1988-07-01), Wong
patent: 5060508 (1991-10-01), Wong
patent: 5163332 (1992-11-01), Wong
patent: 5340986 (1994-08-01), Wong
patent: 5488227 (1996-01-01), Sweet
patent: 5550375 (1996-08-01), Peters et al.
White, John U., "Long Optical Paths of Large Aperture", J.O.S.A., vol. 32, May, 1942, pp. 285-288.
Font Frank G.
Ratliff Reginald A.
LandOfFree
Gas sensor does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Gas sensor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gas sensor will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-566794