MACHINE ET PROCEDE DE LECTURE DE CARTES CONTENANT DES ECHANTILLONS MEDICAUX

Medical specimens suspected of containing certain microorganisms are introduced into cards containing wells having culture media therein. A reduction in the light transmitting characteristics of any well indicates the presence of a microorganism. Each well is examined at periodic intervals by projecting a light through it. This light is monitored by a plurality of detectors located beyond, but nevertheless, in alignment with the well, and each detector provides a signal which is proportional to the intensity of the light cast upon it. If a detector registers an unduly large decrease in light transmission, whereas others associated with the same emitter do not, this probably indicates the presence of a bubble in the well, and the unduly large decrease is ignored. This enables the machine to look around bubbles. Adjustments are made for the change in light transmission caused by distortion of the flexible walls at the ends of the wells. Each card has identification segments which are composed of different bars, and each bar is read by an emitter which projects light through it and a plurality of detectors which are illuminated by the emitter, unless the bar is blocked out with a marking. A predetermined number of the detectors must register a light intensity above a prescribed threshold value to establish the absence of a marking in the bar which is read, and this enables the machine to disregard stray marks and foreign particles on the card. The card is moved incrementally through a reading head as the viewing wells and identification segments on it are read.