Hitachi, Ltd.

Hitachi Video Engineering, Incorporated

Kosuke Ozeki

Michitaka Ohsawa

Kuninori Matsumi

Makoto Shiomi

Kenji Sato

Toshiyuki Sakamoto

Ikuo Yuki

Tadahiro Kawagishi

A digital convergence correcting device effecting convergence correction by using convergence correcting data stored in a memory which includes an address fixing device which, in the case where convergence correcting data are insufficient, reads out in succession the correcting data corresponding to the last horizontal scanning line for the portion lacking in the data so that the correcting data are used repeatedly, and which, in the case where convergence correcting data are excessive, only necessary convergence correcting data are used.

Correcting data reading device in a digital convergence correcting device

A convergence correcting apparatus is used in a projection television receiver including a CRT having an aspherical fluorescent screen and a projection lens apparatus which is attached to the display screen of the CRT and has aspherical plastic lenses. In the digital convergence correcting apparatus, a digital memory stores digital correction data corresponding to correction values of convergence adjustments points indicative of a plurality of points on the display screens divided in the horizontal and vertical directions. A multiplexer reads out predetermined digital correction data from the digital memory and time sharingly multiplexes. At least one digital/analog converter receives the time sharingly multiplexed data from the multiplexer and generates an analog signal. Sample and hold circuits extract a predetermined correction signal from the analog output of the digital/analog converter and sample and hold them. The convergence correcting apparatus is driven in accordance with the respective correction signals held by the sample and hold circuits.

Digital convergence correcting apparatus

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Yokohama, Japan

Kosuke Ozeki