Patent GB-833501-A (GB)
Title: Method of and apparatus for producing direct records on paper or other material of the trace of a light spot or spots
IPC: G01R13/04
Filed: 1956-06-22
Abstract: 833,501. Photo-electric apparatus. FRISCHEN, F. June 22, 1956 [July 8, 1955], No. 19480/56. Class 40 (3). In an arrangement for producing a permanent record of the trace on an oscilloscope the moving light spot 1 (Fig. 1), of the latter is directed on to a photo-electric device 44 via a rotating disc 19 having a number of slots 21a ... 21d, thus producing a sequence of electric pulses which after amplification at 6 are supplied to a contact disc 19a rotating synchronously with disc 19 and provided with contact arms 22a ... 22d co-ordinated with respective ones of the slots in disc 19 and co-operating with a series of fixed contacts 23 extending spatially over a distance equal to the maximum sweep of spot 1 individual contacts of the series being connected over separate conductors to individual ones of a series of recording beads 16 which produce the required record on a moving recoil strip 12a. The recording arrangement may consist of (1) a number of hammer relays which print coloured dots on a (paper) record strip; (2) a series of spark gaps which produce perforations in a paper sheet having a carbon base; or (3) a series of electrodes producing discoloration of a suitably prepared record strip by electro-chemical action, the record trace in each case approximating more closely to a continuous trace as the speed of the discs increases in relation to the velocity of spot 1. When it is desired to produce a continuous record trace the embodiment shown in Fig. 2 may be employed. In this arrangement light from one or more spots on the oscilloscope 3 is directed on to the photo-electric device 44 via a prismatic optical wedge 26 and a rotating mirror drum 24 the individual mirrors 25 on which are set obliquely in relation to the wedge so that as the drum rotates light is reflected towards lens 28 and device 44 from the spot 3, the position of which coincides with the position of the point of (effective) intersection of a mirror 25 and the wedge 26. The resulting pulse output of 44 may be employed to produce the record by utilizing the recording arrangement described in connection with the embodiment of Fig. 1, or, as shown in Fig. 2 an electro-chemical record may be produced on a strip of suitably prepared paper which is fed between a fixed wedge contact 10 and a drum 29 provided with metallic strip elements 30 inclined with respect to wedge 10 in similar manner to mirrors 25 and optical wedge 26 on drum 24, the two drums being driven in synchronism. To make the trace to be recorded visible independently of the record strip a revolving viewing drum 27 the surface of which is coated with a fluorescent substance is positioned to receive light reflected from the wedge 26. Alternatively, a stationary viewing window, also coated with a fluorescent substance and across which the light spots are swept by means of a revolving mirror drum may be employed. Reference is made to the use of electromagnetic and electronic means for producing the discrete light pulses from the oscilloscope trace and for converting such pulses into corresponding electrical pulses. It is also stated that a plurality of light spots corresponding to the image obtained by scanning a picture may be recorded.