A system of overcoming the time lag in a selenium or other light-sensitive cell used in a television or like system

摘要

235,619. Baird, J. L., and Day, W. E. L. March 12, 1924. Drawings to Specification. Television apparatus; selenium cells.-Inertia effects in a selenium or like cell used at the transmitting station of a television or like system are minimized by the provision of means for interrupting at high frequency the light incident on the cell. The interrupter may comprise two coaxial discs rotated at high speeds in opposite directions, the edges of the discs being either finely serrated radially or provided with narrow radial strips alternately opaque and transparent. Alternatively one such disc may be rotated with its edge adjacent to a grid with bars spaced similarly to the serration. According to the Provisional Specification an image to be transmitted may be focused on a stationary or moving grid, and successive areas of the image be projected on to the cell by spirally arranged perforations or lenses in a rotating disc, the cell being in series with a battery and the primary of an induction coil, and the current from the secondary of this coil being transmitted.