Display-controlling means for cathode ray tubes
United States Patent 2718608

736,557. Photo-electric waveform generators. ELLIOTT BROS. (LONDON), Ltd. May 14, 1954 [May 18, 1953], No. 13954/53. Class 40 (3). [Also in Group XL (c)] In an arrangement for displaying predetermined patterns or symbols on the screen of a display cathode-ray tube by simultaneously varying the displacement voltages applied simultaneously to the X and Y plates of the tube, the X displacement voltage is generated by rotating a transparent disc 1 between an auxiliary C.R.T. 12 and a photo-cell 13, the disc having an opaque annular track 2 whose outer contour corresponds to the required variation of the displacement voltage and the output from the photo-cell 13 being applied through an amplifier 14 to control the deflection of the beam of C.R.T. 12 so that the luminous spot on the screen of C.R.T. 12 is maintained at the outer edge of the track 2 ; the output from amplifier 14 thus constitutes the required displacement voltage and is also applied to the X plates of the display C.R.T. (not shown). The Y displacement voltage is generated by a similar arrangement comprising a disc 1a, discs 1 and 1a being driven by a single motor 11. When a plurality of different patterns are to be displayed sequentially in displaced positions, the pattern contours 3 ... 8 are arranged end-toend along the track and disc 1a includes an additional track 15 comprising alternate opaque and transparent areas which in conjunction with lamp 16 and photo-cell 17 produces a control voltage which operates switches for applying the shift voltages to the plates of the display C.R.T. ; alternatively the switches may be controlled by a further contour-following C.R.T. Brightening pulses may be generated in a similar manner.

Alfred, Laws Cecil
Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
250/237R, 250/549
International Classes:
G06K11/02; G09G1/12
View Patent Images:
US Patent References: