<P> As the electron gun is tilted compared to the screen, its image of the screen is not as a rectangular plate, but a keystone shape . Additionally, the time needed for the electrons to reach the upper portions of the screen was longer than the lower areas, which were closer to the gun . Electronics in the camera adjusted for this effect by slightly changing the scanning rates . </P> <P> The accumulation and storage of photoelectric charges during each scanning cycle greatly increased the electrical output of the iconoscope relative to non-storage type image scanning devices . In the 1931 version, the electron beam scanned the granules; while in the 1925 version, the electron beam scanned the back of the image plate . </P> <P> The problem of low sensitivity to light resulting in low electrical output from transmitting or "camera" tubes would be solved with the introduction of charge - storage technology by the Hungarian engineer Kálmán Tihanyi in the beginning of 1925 . His solution was a camera tube that accumulated and stored electrical charges ("photoelectrons") within the tube throughout each scanning cycle . The device was first described in a patent application he filed in Hungary in March 1926 for a television system he dubbed "Radioskop". After further refinements included in a 1928 patent application, Tihanyi's patent was declared void in Great Britain in 1930, and so he applied for patents in the United States . </P> <P> Zworykin presented in 1923 his project for a totally electronic television system to the general manager of Westinghouse . In July 1925, Zworykin submitted a patent application for a "Television System" that includes a charge storage plate constructed of a thin layer of isolating material (aluminum oxide) sandwiched between a screen (300 mesh) and a colloidal deposit of photoelectric material (potassium hydride) consisting of isolated globules . The following description can be read between lines 1 and 9 in page 2: The photoelectric material, such as potassium hydride, is evaporated on the aluminum oxide, or other insulating medium, and treated so as to form a colloidal deposit of potassium hydride consisting of minute globules . Each globule is very active photoelectrically and constitutes, to all intents and purposes, a minute individual photoelectric cell . Its first image was transmitted in late summer of 1925, and a patent was issued in 1928 . However the quality of the transmitted image failed to impress to HP Davis, the general manager of Westinghouse, and Zworykin was asked to work on something useful . A patent for a television system was also filed by Zworykin in 1923, but this file is not a reliable bibliographic source because extensive revisions were done before a patent was issued fifteen years later and the file itself was divided into two patents in 1931 . </P>

Who invented and patented the inconoscope pickup tube for tv