arrangement for generating electrical signals using a aufnahmeroehre with fangelektrode of ladungsspeichertyp

摘要

760,950. Television pick-up tubes. ELECTRIC & MUSICAL INDUSTRIES, Ltd. Nov. 18, 1954 [Nov. 26, 1953], No. 32797/53. Class 39(1). [Also in Group XL(b)] A television pick-up tube arrangement has a scanning light spot for generating signals and electron beam scanning for stabilizing the target to datum level, the latter performed in the period between the light spot scanning intervals. In Fig. 1, the mosaic target 2, 3 receives both the image scene 12 and the light spot from scanner tube 13, the latter reflected by a half silvered mirror 14. The stabilizing beam from gun 5, 6, 7 is scanned over the target and focussed by coils 8, 9. A grid 11 limits the potential to which the target can be charged. In Fig. 2 (not shown), an electron beam is produced by scanning a photo cathode with a light spot, thereby avoiding the use of scanning coils. A reference signal at the end of each line scansion representing peak white is obtained by switching off the light scanner 13. In a further modification, Fig. 4 (not shown), an electron multiplier section e.g., an apertured dynode adjacent a ring electrode, is positioned near the gun 5, 6, and receives the electrons liberated by the light spot under the control of the scanning coils. The signal is taken from the multiplier and not from the signal plate. In Fig. 5, the tube is cathode potential stabilized, with a photo cathode 26 receiving the scene and the scanning light spot. A wall anode 33 directs the photo electrons at high velocity onto a target 27 comprising a then semi-conducting glass sheet, the secondary electrons liberated at the target being collected by mesh electrode 28 from which the signal is taken. The beam from gun 5, 6, 7, discharges the target, and a blanking circuit is included in the amplifier 30 of the output, to suppress the signal due to the discharging current. Reference signals are obtained from the border region of the photo-cathode, by flooding with light from a lamp 32 through a slotted mask 31. In all examples, the stabilizing may be performed only once during every few such line periods using a defocussed beam or by causing the beam to oscillate across several lines. Alternatively the cathode is a strip giving a flat deflected beam. The specification describes the grid action of the dielectric surface between the mosaic elements and control of the potential of the wall anode to prevent the potentials of the mosaic elements rising above the first cross-over potential.