GB382326A - Improvements in or relating to television systems - Google Patents

Abstract

382,326. Television. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., Strand, and DOWSETT, H. M., 47, Drayton Gardens, Winchmore Hill, both in London. July 27, 1931, No. 21452. [Class 40 (iii). ] With the object of reducing flicker and improving definition, the received picture has superposed upon it a light grid or frame so that, in observing a picture, the intensity of each elementary area is visually compared with the intensity of the adjacent grid lines as a basis. The mesh of the grid preferably corresponds to the number of elements, and its lines lie on the dividing lines between the elements, but a single grid or frame completely surrounding the complete picture may be employed. Preferably the intensity of the illumination in the grid lines approximates to the average intensity of the picture elements, and may either be constant or may be modulated in an opposite sense to the picture modulation. In the arrangement shown in Fig. 1, the picture signals are applied to a bank of lamps 1 situated behind a ground glass or like screen 2, and a number of small lamps 3 of uniform intensity is arranged between the lamps 1 to form the grid. In another arrangement, Fig. 3, the picture elements 7 are displayed by means of a television projector 5 upon the front of a translucent screen 4, which is viewed from the front by reflected light, while a lantern slide or equivalent device 6 having a grid marked thereon is projected upon the rear of the screen. Alternatively, both the picture elements and the grid may be projected on the same side of the screen and be viewed together either by reflected or transmitted light.