Abstract:
An illumination device is provided with a light source, a photodetector, and a support structure. The light source, which emits light, has light distribution in which a reference axis serves as an axis of symmetry or light distribution in which a plane including the reference axis serves as a plane of symmetry. A first light beam in the light is guided to the object to be illuminated. A second light beam in the light is guided to the photodetector. The photodetector detects intensity of the second light beam. The light source and the photodetector are supported by the support structure in positions and postures that allow the first light beam and the second light beam to be guided in an aforementioned manner. A traveling direction of the first light beam and a traveling direction of the second light beam make the same angle with the reference axis.
Abstract:
A dual wavelength optical sensor for measuring chemical properties of a particular quantity, the optical sensor including a sensor probe having a thin sensing film whose optical characteristics are responsive to the chemical properties of the measured quantityThe United States Government has certain rights in this invention pursuant to Contract No. ITA87-02 between the U.S. Department of Commerce and Iowa State University.
Abstract:
Color changes in a target, such as a chemical sensor using a colorchanging indicator reagent to detect the presence of a poisonous gas, are continuously monitored by reflecting the target (10) on to a sensor (16) light originating from first one and then another light source (12a, 12b, etc), each having a different, known emission wavelength. In each cycle, direct light from the appropriate source is also collected by another sensor (14), connected in a closed loop (26) with circuitry in which the emission intensity is compared with a known reference value (38) and which adjusts the emission intensity so as to stabilize it at this constant reference value. Once this is stabilized, the reflected light intensity signal is passed to a data store (20), after which a divider (22) produces an output signal (36) representing the ratio of the reflected light intensities in two separate cycles originating from two different light sources (12a, 12b, etc). The conduct of each cycle is controlled by timing means (18). Where there are two light sources, the wavelength of the second (12b) is outside the response range of the target, that of the first (12a) being at or near the peak target response, so that all the divider output signals represent successive values of actual reflected light intensity. These signals can be processed to show the rate of color change in the target and used to operate e.g. an alarm.
Abstract:
An apparatus for measurement of optical reflection density of a surface of an article, such as a color developed analytical tape for clinical test. The apparatus comprises a support for supporting the article, a source of pulsed light and two light detectors. An optical guide directs the pulsed light to the surface of the article in a direction at an angle other than 90.degree. to the surface of the article. A light-transmissive flat plate is arranged between the optical guide and the surface of the article and may be oriented at an angle from 0.degree. to 90.degree. with the surface of the article to be measured. One of the light-detectors detects a portion of the pulsed light reflected from the surface of the light-transmissive flat plate as reference light, and the second light-detector detects a vertically reflected portion of the pulsed light diffusely reflected on the surface of the article. Light detected from the second detector may be provided for analysis after comparison with respect to the reference light of the first detector.
Abstract:
Instrumentation for measuring the amount of material dissolved in a liquid solution which utilizes electro-optic technology based on the Beer-Lambert Law is implemented either as a portable, battery powered model or integrated in an automated process monitoring system. In the portable, battery powered model, a sample probe (14) is inserted into a solution to be measured. The results of the measurement are displayed on a display (22). The displayed results are frozen for a predetermined period of time at the expiration of which, the power is turned off to conserve battery power. In the automated process monitoring model, a solution loading analyzer (100) is supplied with a sample of solution to be analyzed. A probe (14) positioned in a measurement well (200) is used to determine the ratio of incident light to light transmitted through the sample. A spray nozzle (212) is used for cleaning the probe head (16).
Abstract:
The invention is directed to a reflectance measuring apparatus for making contactless measurements on structured test objects wherein the measuring result is independent of the distance of the test object within a difference range (d). The illumination arrangement and the measuring arrangement have a common center axis (z) which extends perpendicularly to the surface of the test object. At least the illumination arrangement or the measuring arrangement includes at least three radiation transmitters or three radiation receivers having optical axes arranged on at least one cone (c) concentric with respect to the common center axis (z). Of the set of radiation transmitters and the set of radiation receivers, one of the sets is configured to have a parallel ray bundle with a core area (k) and the other one of the sets is configured to have a bundle having a limited aperture with the area (m) covered by the limited aperture or apertures being smaller than the core area (k) within a distance range (d).
Abstract:
A spectrofluorophotometer enabling spectrum correcting treatment to be done highly accurately, including an intercepter the incident light in a fluorescence detecting system, and an interceptor intercepting the incident light in a monitoring detecting system, so as to carry out zero point correction for both of these detecting systems.
Abstract:
The extinction coefficient of atmospheric aerosol is measured by an instrument in which a single light beam from a graybody source is alternately directed through two similar optical paths to a detector. Each optical path traverses an equal length region of ambient air. Aerosols are filtered from the ambient air region of one optical path .The detector measures the modulation of the incident radiation and its output is a function of the extinction coefficient of the ambient air under test. A second detector is used to monitor the beam power. Processing electronics compute the extinction coefficient of the ambient air under test from the detector outputs. The ambient air regions of the two beam paths are alternately filtered for improved performance.
Abstract:
In a exhaust smoke sensor a light emitter generates a light beam which passes through a region containing the exhaust gas to a first light sensor. To reduce interference the light emitter is driven by a near square wave signal produced by passing a square wave through a low pass filter.
Abstract:
Apparatus and method for spectroscopic analysis of scattering media. Subtle differences in materials have been found to be detectable from plots of intensity as a function of wavelength of collected emitted and scattered light versus wavelength of excitation light.