PHOTOCOLORIMETER-REFLECTOMETER Russian patent published in 2002 - IPC

FIELD: opticomechanical electron equipment for spectral analysis. SUBSTANCE: invention specifically refers to photocolorimers-reflectometers measuring passage of liquids ( in ampoules, dishes, test tubes ) and diffuse reflection of solid test means ( in the form of paper, tablets, films ) capable of changing color while exposed to action of various substances. Proposed photocolorimeter-reflectometer can be used as tool for proximity quantitative determination of microcomponents in liquid and gaseous media at point of sample taking, for instance, in the field. Photocolorimeter-reflectometer incorporates two optrons comprising radiation sources and photodetectors connected in differential circuit and forming two optical channels, one being employed as reflection channel to form reflectometer in which longitudinal axis of photodetector is located at angle 2α with longitudinal axis of radiation source and shortest distances ≪r₁≫ from center of butt of radiation source to center of light spot on examined surface and ≪r₂≫ from center of light spot on examined surface to center of butt of radiation source satisfy relationship ctgα = r₁/(0.5d₁+a₁) = r₂/(0.5d₂+a₂) and consequently r₁,r₂= r₁x(0.5d₁+a₂)/(0.5d₁+a₂), where α is angle included between direction of radiation propagation and perpendicular to examined surface ( preferably, α > 45^° ); d₁ is width of light beam of radiation source ( preferably, 2-6 mm ); d₂ is width of light beam from radiation source to photodetector; a₁ is distance from butt of light-emitting diode to point of crossing of perpendicular to examined surface in center of light spot with plane in which butt of light-emitting diode is located; a₂ is distance from crossing point of perpendicular to examined surface in center of light spot with plane in which butt of photodetector is located. In this case set of switchable light-emitting diodes is used as radiation sources and photodetector is connected via operational current amplifier to measurement unit incorporating microprocessor connected by system bus to analog-to-digital converter of transfer of response of photodiode to digital form of indicator, on-line storage, permanent storage recording algorithms of measurement unit and controller of liquid-crystal indicator. EFFECT: simplified measurement circuit, expanded application field. 10 dwg