Abstract: A method for measuring pressure differences in different premises of a building, in which the pressure difference is measured using one or more sensors (2) that measure absolute pressure. The measurement results obtained from the sensors (2) are combined with information on the efficiency of the ventilation of the building, and the pressure difference caused by ventilation is mathematically separated from the measurement result by making use of information on the ventilation efficiency at any one time.

Abstract: The invention relates to a method for measuring pressure differences in different premises of a building, in which the pressure difference is measured by means of one or more sensors (2) that measure absolute pressure. The measurement results obtained from the sensors (2) are combined with information on the efficiency of the ventilation of the building, and the pressure difference caused by ventilation is mathematically separated from the measurement result by making use of information on the ventilation efficiency at any one time.

Abstract: An exemplary method for measuring a refractive index of a substance being measured through an optical window, includes arranging the optical window in contact with the substance being measured, directing light to the interface of the optical window and substance being measured, where part of the light is absorbed by the substance being measured and part of it is reflected from the substance being measured to form an image, in which the location of the boundary of light and dark areas expresses a critical angle of the total reflection dependent on the refractive index of the substance being measured, and examining the formed image. Light is directed on a first structure and to desired angles on an interface between the optical window and substance being measured. Light reflected from the interface of the optical window and substance being measured is directed on a second structure.

Abstract: An exemplary method for measuring a refractive index of a substance being measured through an optical window, includes arranging the optical window in contact with the substance being measured, directing light to the interface of the optical window and substance being measured, where part of the light is absorbed by the substance being measured and part of it is reflected from the substance being measured to form an image, in which the location of the boundary of light and dark areas expresses a critical angle of the total reflection dependent on the refractive index of the substance being measured, and examining the formed image. Light is directed on a first structure and to desired angles on an interface between the optical window and substance being measured. Light reflected from the interface of the optical window and substance being measured is directed on a second structure.

Abstract: The invention relates to a method for in-line measuring the active KOH concentration in a KOH etching process in which process silicon hydroxide is produced by a reduction reaction according to the formula: 2K+ (aq.)+2OH? (aq.)+2H2O+Si?2K+ (aq.)+H2SiO42? (aq.)+2H2 (g). The total concentration of KOH bath is measured by using a refractometer and the measurement result is corrected by the estimated K2H2SiO4 concentration.

Abstract: A method and an arrangement of measuring acidity or other chemical or physical property of a gas. The invention comprises a membrane having optical indicator molecules bound to a microporous matrix arranged to be placed into contact with the gas to be measured, the optical indicator molecules changing their colour in response to the acidity or other chemical or physical property of the gas, a light source, and a detector. The light source is arranged to emit and direct light to the membrane, the light being transmitted through the membrane, whereby a part of the light is absorbed into the optical indicator molecules, and the rest of the light emitted is guided to the detector, where it is measured.

Abstract: The invention relates to a method for in-line measuring the active KOH concentration in a KOH etching process in which process silicon hydroxide is produced by a reduction reaction according to the formula: 2K+ (aq.)+2OH? (aq.)+2H2O+Si->2K+ (aq.)+H2SiO42? (aq.)+2H2 (g). The total concentration of KOH bath is measured by using a refractometer and the measurement result is corrected by the estimated K2H2SiO4 concentration.

Abstract: A method and an arrangement of measuring acidity or other chemical or physical property of a gas. The invention comprises a membrane having optical indicator molecules bound to a microporous matrix arranged to be placed into contact with the gas to be measured, the optical indicator molecules changing their colour in response to the acidity or other chemical or physical property of the gas, a light source, and a detector. The light source is arranged to emit and direct light to the membrane, the light being transmitted through the membrane, whereby a part of the light is absorbed into the optical indicator molecules, and the rest of the light emitted is guided to the detector, where it is measured.

Abstract: An optical conductor comprising a rod-like part made of a light-conducting material. To accomplish a mechanically durable structure, a side surface of the rod-like part is provided with a groove, at least one side surface of which is arranged to form a surface acting as a reflective or permeable surface for light.

Abstract: A method for manufacturing thin film and a thin film. The method comprises dipping a substrate in a solution that dries up forming a layer on the surface of the substrate and controlling layer thickness by changing the rate of dipping the substrate in the solution. Before the next dipping after the first dipping, the position of the substrate is changed such that the next dipping will be carried out in a direction which is at an angle to the direction of the previous dipping.

Abstract: An optical conductor comprising a rod-like part made of a light-conducting material. To accomplish a mechanically durable structure, a side surface of the rod-like part is provided with a groove, at least one side surface of which is arranged to form a surface acting as a reflective or permeable surface for light.

Abstract: A method for manufacturing thin film and a thin film. The method comprises dipping a substrate in a solution that dries up forming a layer on the surface of the substrate and controlling layer thickness by changing the rate of dipping the substrate in the solution. Before the next dipping after the first dipping, the position of the substrate is changed such that the next dipping will be carried out in a direction which is at an angle to the direction of the previous dipping.

Abstract: The invention relates to an arrangement at measurement of pH or another chemical property detectable by dye indicators. To provide a simple and safe solution, the measuring part is formed of a glass sheet or a similar substrate, the substrate being coated with a dye film, which is arranged to change its color in a manner known per se when a chemical property of the environment changes. The dye film is arranged to serve as a light reflective surface, whereby the chemical property of the solution to be measured can be measured as light reflection measurement.

Abstract: A colorimeter for measuring colour of process medium comprising two light sources and two detectors both light sources being arranged to emit a beam through the process medium and the windows adjoining the process medium to both detectors. In order to achieve a solution functioning reliably the windows adjoining the process medium at both light sources are formed from a triangular prism, the two surfaces of which being at an angle to each other, are arranged to divide the beam arriving from the light source into two beams travelling in different directions so that both beams proceed to the process medium through the same part of the window surface formed by a third surface of the prism. Mirror surfaces arranged to gather radiation arriving form both light sources to a sensor of the detector are formed at both detectors.