Abstract: An apparatus for determining the flow of matter passing through a boundary surface, which is provided with at least one sensing layer corresponding to the boundary surface, and presents a known or predetermined, finite resistance to the material flow, and wherein an optical indicator is provided in the sensing layer for obtaining a first measured value of a quantity dependent on the mean concentration of matter in the sensing layer, and wherein a second measured value of this quantity is known on one side of the sensing layer, or can be determined by means of another optical indicator provided in a second sensing layer, and, further, wherein an evaluation unit is provided for inferring the material flow from the difference of the two values measured.

Abstract: In a sensor arrangement for direct or indirect optical determination of physical or chemical parameters, in human and animal bodies, the sensor arrangement including an indicator cell which is permeable to the chemical substance or physical quantity to be measured and which contains one or more indicators, a radiation source supplying the excitation radiation for the indicator, and a detector for detection of the response radiation emitted by the indicator, the indicator cell is configured as a capsule which may be introduced into body cavities, such as mouth, nose, stomach, intestine, blood vessels, bronchial tubes, urinary bladder, or which may be implanted in the tissue, and the material used for this capsule is transparent to excitation radiation and to the response radiation emitted by the indicator in the range of wavelengths between 600 and 1,300 nm, and the material of the capsule, or rather, its outer layer, is bio-compatible.

Abstract: In order to simultaneously determine the concentrations of different analytes in several places in a tissue by means of a thin, biocompatible tube or cannula which is inserted into the tissue, the tube is provided with several areas along its length which contain either identical or different optically excitable and readable, preferably luminescence-optical, indicating substances for measuring the local distribution of one parameter, such as O.sub.2 concentration or O.sub.2 partial pressure, or for simultaneous measurement of at least two different parameters, e.g., pO.sub.2, pCO.sub.2 or pH.

Abstract: An arrangement for optical measuring concentration of substances has a measuring space which is composed of a material selectively permeable for particles to be measured, acting back on the particles and transparent for a measuring radiation, and a measuring space is arranged in working connection with the object to be measured and the measuring radiation passes through the measuring space. The measuring space has a layer that is a water-insoluble solvent or made of poly(ethylene terephthalate) or polytetrafluoroethylene. The layer excludes a reaction from the particles to be measured.

Abstract: An optode designed to prevent washing away of the indicator and reagent from a membrane is located within an optical device that measures substance concentrations. The reagent and indicator materials are covalently bound on the membrane. The membrane can be a polysaccharide, especially cellulose, an acid glycol ester, or it can contain silicon. The indicator and/or reagent can be covalently bound to the membrane by a bridge molecular, particularly a multifunctional aldehyde, glutaraldehyde or a silane.

Abstract: A sensing arrangement for measuring physical parameters or concentration of particles is assembled of a laminar source of luminescent radiation. Fluorescent indicating particles are arranged in an indicator layer adjoining one major side of the laminar light source. The indicator layer adjoins a measuring space containing the object of measurement whose particles enter the indicator layer by diffusion. Fluorescent indicating particles are arranged in the indicator layer to emit fluorescent light when illuminated by the laminar light source. Photoelectric receiver is adjacent the opposite side of the laminar light source to measure the intensity of the fluorescent radiation. In a modification, luminescent phosphors and fluorescent particles are arranged in a common matrix.

Abstract: To measure potential differences in second-class conductors without interference potentials, there are provided a potential generator cooperating with a potential-measuring structure. This structure includes a substrate of electrically highly insulating and chemically inert material embedding optical indicators whose optical properties change as a function of the applied electric potential difference. Both the potential generator and the potential-measuring structure have boundary surfaces which are in contact with the second-class conductor and opposite surfaces interconnected by an equalizing conductor. A light-measuring device is arranged for intercepting light changes in the indicators, thus measuring the potential difference.

Abstract: In order to increase measuring sensitivity of a fluorometer, a transmitter of monochromatic test light beam is arranged opposite a receiver of a measuring light beam. A measuring chamber including a fluorescent indicator space is arranged between the transmitter and the receiver. The distance between the transmitter and the receiver is adjustable to match to the thickness of the measuring chamber.

Abstract: An optical indicator device for the remote indication and measurement of physical changes in a living body includes at least one source of light disposed remote from the test subject and at least one indicator disposed in direct contact with the test subject. This indicator includes a fluid-tight, light-permeable membrane which encloses an inner space. A liquid crystal compound is disposed in the inner space. This compound is of the opto-electrical type adapted to respond to light waves from said source of light and furthermore responsive to physical changes in the space surrounding said indicator. Detector means are provided for indicating and measuring the response of said liquid crystal compound to said light rays and physical changes. Preferably, the indicator device is combined with a similar device containing a different liquid crystal for measuring the glucose concentration.

Abstract: An arrangement for measuring diffusing particles has at least one monochromatic radiation source and a light measuring device, as well as at least one material limited particle-permeable indicator chamber provided with an optical fluorescent indicator which is optically changeable by the particles to be measured, and a carrier body having a surface which is arranged to face an eyelid and has depressions in which the indicator chambers are arranged.

Abstract: Process and apparatus for directly measuring the ion strength of an electrolyte solution is disclosed. The pH value of the electrolyte is measured by means of a first measurement with a first indicator dependent on the ion strength and by means of a second measurement with a second indicator dependent on ion strength in a manner different from the first indicator whereby the ion strength is computed by means of the approximation ##EQU1## J=ion strength Jo=ion strength upon calibrationpH'(N)=pH value, measured with a first indicator N dependent on the ion strength (HPTS)pH'(X)=pH value, measured with a second indicator X dependent on the ion strength, the ion strength dependence of which is different from that of the first indicatorW(N)=valency of the first indicatorW(X)=valency of the second indicatorwith ##EQU2## The ion strengths of other ions and of unknown electrolyte may also be computed.

Abstract: A light conductor wherein one of its opposite ends is divided in a plurality of separated strands, each of which is coordinated with a specific one of a plurality of regions at the other end arranged in any desired pattern and a method for producing such a light conductor.

Abstract: The concentration of a substance of interest is measured by exposing a peable-membrane face of an indicator chamber containing an indicator to the substance, monochromator radiation being incident upon the indicator through a transparent wall of the indicator chamber, the exiting radiation being received by a light-metering unit for ascertainment of the effect upon the indicator's absorbence of fluorescence of the substance of interest. The indicator substance is additionally exposed to a reference substance of known concentration which is permitted to engage the indicator substance by diffusion through such permeable membrane, in order that the indicator be calibrated.

Abstract: A spectral photometer emits light towards an object of interest, receives e light reflected back from the object of interest, and includes a timer or synchronizer operative for causing the spectral photometer to produce an output signal whose successive values correspond to the intensity of the spectrum derived from the object of interest at successive wavelengths. The spectral photometer output signal is applied to an oscilloscope for display of the thusly generated spectrum. The oscilloscope screen is provided with interpretation marks at characteristic points of the displayed spectrum, either by providing such marks on a transparent plate mounted in front of the screen, or by applying to the oscilloscope signals causing the scope itself to generate these marks. These marks may be curves shaped and located to be intersected by both maxima of an oxygenated-hemoglobin spectrum irrespective of the degree of oxygenation.

Abstract: In an indicator chamber (e.g., optode) arrangement including an indicator d a membrane which surrounds it and is impermeable to it, a carrier substance is provided within said membrane for transport of particles to be measured into the indicator chamber. Said carrier is mobile within said membrane. This improvement allows for the preparation of highly selective indicator arrangements and broadens the range of applicability of the method of measurement.

Abstract: In order to improve the selectivity of an indicator chamber or optode conting of an indicator and a membrane impermeable to the indicator and surrounding it, for use in the measurement of concentration of component particles by means of an optical light measurement system including a light source, a light receiver and a readout device, a substance which reacts with the particle to be measured is provided within the indicator chamber, and the reaction product then modifies the optical properties of the indicator.

Abstract: Monochromatic excitation light penetrates an indicator in an indicator sp. The indicator space is closed off at the side to be brought into contact with the substance to be analyzed by means of a membrane permeable for the component of the substance whose concentration is to be ascertained. The side of the indicator space facing the light-measuring unit of the device is radiation-transmissive. The indicator is set into motion during the measurement operation. Alternatively, the substance to be analyzed, on the other side of the permeable membrane, is set into convective motion during the measurement operation. As a further alternative, both the indicator and the substance to be analyzed are set into motion in mutually perpendicular directions, which however are both parallel to the permeable membrane.

Abstract: An apparatus for an optical measurement of the concentration of substances ncluding at least one monochromator means, one photometer means and one optometric means. A further reference indicator means is added to the indicator means. This further indicator means changes the measuring light and will not be changed by the concentration of the substance to be measured.

Abstract: A housing contains a light source, a monochromator, a photosensitive unit and an oscilloscope-type display. A flexible bundle of fiber-optic elements extends from within the housing out, and is provided at its outer end with a spacing ring. The spacing ring is placed against a skin surface, holding the ends of the fiber-optical bundle properly spaced and oriented relative to the skin surface. At the other end of the bundle, the bundle is subdivided into one branch which receives light from the source, and another branch which emits light refleced from the skin surface into the monochromator. The monochromator projects the spectrum of the skin-reflected light onto the photosensitive unit. The output signal of the photosensitive unit, in a sequential and periodic manner, contains information concerning successive spectral components of the skin-reflected light. The sweep of the display is synchronized with this periodic sequence, so as to display a spectral analysis of the skin-reflected light.

Abstract: A method and an arrangement for measuring the concentration of gases in a sample includes the generation of a monochromatic light beam having predetermined color characteristic. An indicator generates light signals indicative of the concentration of the gases in a sample to be measured and includes a light-transmissive surface positioned to be impinged by the monochromatic light beam, a diffusion membrane adapted to be placed in the proximity of a sample and being permeable to a selected gas component thereof, and an indicating substance positioned to be impinged by the monochromatic light beam penetrating the light-transmissive surface and by the gas component penetrating the diffusion membrane. The indicating substance reacts when illuminated by the incident monochromatic light by emitting a resultant light beam having an emitted component which has a color characteristic different from the predetermined color characteristic of the monochromatic light beam.