Radio age research, manufacturing, communications, broadcasting, television (1941)

form a single image blended in the same colors as the original. Dr. Zworykin, who recently re- ceived the Potts Medal of The Franklin Institute for his outstand- ing contributions to television, pointed out that color television is passing through a series of devel- opment stages similar, in many re- spects, to those that black-and- white television passed through in its progression toward perfection. He said that a great step was made in the advance of television when RCA developed the simultaneous all-electronic color system, which eliminated all mechanical parts and rotating discs. Compatible With Present System "This system is completely com- patible with existing monochrome television and has other important advantages," he continued. "The transition from monochrome to simultaneous color television can be made at a time in the future when color television is ready, without obsolescence of the monochrome re- ceiving and transmitting equip- ment. It can from that time be developed side-by-side with black- and-white television without fear of obsolescence of the latter and without loss of investment by the public, by manufacturers and by television broadcasters. The prog- ress that has been made so far in color television—and it is not in- considerable—has been due to the efforts of many men working in close cooperation." In presenting the demonstration. Dr. Zworykin said that develop- ment of this large-screen color tele- vision system was the result of cooperative efforts of several re- search groups at RCA Laboratories. He said that specific credit should be accorded to the following mem- bers of the staff: R. D. Kell, Tele- vision Section Head, and his asso- ciates, for developing the principles of the system; Dr. D. W. Epstein, Cathode-Ray and Optics Section Head, and his associates, for de- signing and building the receiver- projector; also, for contributing to the optical design of the unit; Dr. F. H. Nicoll, Research Engineer, for developing the necessary special projection kinescopes; Joseph Ford, of the Drafting Department, and R. A. Marple, of the Model Shop, for assisting in completion of the apparatus, and A. C. Schroeder, K. R. Wendt and G. C. Sziklai, of the Television Section, for con- tributing to the development of the flying-spot color pick-up unit. Incorporates "Flying Spot" Dr. Zworykin disclosed that the pick-up unit used in the demonstra- tion incorporates the electronic "flying spot" which has been under development for nearly ten years. In this system, he explained, the flying spot of light is created on the screen of the kinescope by the electron scanning beam. The light from this spot is pro- jected through color slides or films, scanning the entire surface of the scene or object, point by point. As the light beam, then tinted with color, emerges from the film or slide, it passes through a series of filters which separate respectively THIS DRAWING SHOWS HOW THE THREE PROJECTION KINESCOPES ARE ARRANGED WITHIN THE LARGE SCREEN ELECTRONIC COLOR PROJECTOR. the red, green and blue portions of the color in the beam. Each color theli is reflected into photocells which change the light values into electrical signals for transmission to the receiver. The flying spot method, he added, as- sures perfect picture registration by permitting the transmission of the three color values of each pic- ture element simultaneously. Tube Advances Outlined Dr. Zworykin revealed that the special projection kinescopes used in this large screen color television system owed their brightness and effectiveness, in large part, to im- provements achieved by RCA since development of the original kine- scope. "Some of these improvements, such as the design of electron guns to operate at higher voltages and to yield smaller, sharper dots, and the development of efficient phosphors, with a wide range of color, have been practically continuous," Dr. Zworykin said. "Other important contributions of relatively recent date, are the use of metal backing for the fluorescent face of the tube and the utilization of an improved optical system." Television of theater-screen size in life-like colors represents "a spectacular advance in the art of sight-and-sound broadcasting, and holds fascinating prospects for the future," declared E. W. Engstrom, Vice President in Charge of Re- search of the RCA Laboratories Division who cooperated with Dr. Zworykin in the Philadelphia dem- onstration. "The purpose of this demonstra- tion," Mr. Engstrom explained, "is to make known to the public the latest advance in RCA's program of all - electronic simultaneous color television development, first intro- duced in October, 1946. "At that time, we demonstrated two stages of our laboratory time- table when we televised still pic- tures from color slides and motion pictures from color films on a home- receiver screen 15 x 20 inches," said Mr. Engstrom. "The next step was disclosed in January 1947, at Princeton, when RCA transmitted live-action studio scenes in color (Continued on page 29) [20 RADIO AGE]