Patent GB-1172412-A (GB)
Title: Improvements in Methods of and Apparatus for Transducing Radiation
Inventor: COZMAN LATIF MORKOS
IPC: H04N5/30
Filed: 1967-01-14
Abstract: 1,172,412. Television. L. M. COZMAN. 4 Jan., 1968 [14 Jan., 1967], No. 2102/67. Heading H4F. [Also in Division G5] An image converter or light-amplifier similar to that described in Specification 996,414, or light-transducer which converts the light from each picture area of a scene simultaneously into electric currents, comprises a conductive glass disc 1, a photo-conductive semi-conductor layer 2, a first mosaic 3 of small conductive glass elements arranged in checker-board pattern and insulated from each other by horizontal and vertical thin linings, a layer 4 of colloidal graphite crystals suspended in a radiationpermeable electrically-insulating liquid, e.g. thin mineral oil, a second mosaic 5 of small conductive glass elements embedded in insulating material and arranged to be symmetrical with the first mosaic, and an electrode 7; glass disc 1 and electrode 7 (effectively mosaic 5, see later) being connected to the positive and negative HT poles of a source of E.M.F. When a visible, infra-red, ultra-violet or X-ray image is incident on disc 1 a corresponding electrical charge image is built up on photo-conductive layer 2 and transmitted via mosaic 3 to layer 4 wherein the graphite crystals align along the lines of force. For the more intense parts of the original scene the voltage is greatest and the liquid suspension will transform from being opaque to being transparent. Intermediate voltages give rise to intermediate orientations of the crystals to corresponding intermediate transparencies. Light from electric lamp bulbs 6 traverses the suspensoid cell 3, 4, 5 and falls on the photo-conductive layer 2 increasing its conductivity and consequently the voltage on its surface, and thus increases the transparency in the cell (equivalent to amplification by feedback). Since the colloidal graphite is a conductor of electricity, the resistance of which decreases as the crystals align, i.e. as layer 4 becomes more transparent, currents will traverse the device from the HT + to the HT- in those unit cells (elements of the mosaic) that are illuminated by light, each current being proportional to the intensity of the light. The device thus converts the impinging light image into discrete electric currents belonging to the various picture-elements represented by the unit cells, and amplifies these currents by feedback. The device may be used to enable a blind person to obtain an impression of his surroundings by attaching the device 1-6 and the electrode 7 to the forehead and to the back of the head respectively by means of an elastic band, Fig. 3 (not shown), the position of the mosaic 5 and electrode 7 on the head being such that the minute electric currents are injected into the relevant brain lobes. The device may be used to read punched cards into a computer (each of the elements of mosaic 5 being provided with a conducting wire) and convert their data into storage systems, e.g. magnetic discs, drums or tapes. Punched data may be transmitted thereby on a light beam and recorded on photographic material by allowing the mosaic 5 to make contact with a disc of conducting glass connected to HT-. Since semi-conductor layer 2 has rectifying properties alternating or rectified current may be used.