| 摘要 |
An optical relay transmits light in dependence on an electric field parallel to the direction of propagation of the light toward a target having a first face which is scanned by an electron beam. An anode collects the secondary electrons emitted by the beam, and an optically transparent and electrically conducting plate is arranged at the second face of the target, the plate receiving the electric video information signal, thereby forming a control electrode. The target is an electrically insulating material which becomes ferroelectric below a certain temperature, called the Curie temperature, in the proximity of which the optical relay operates. In order to keep the target at the required operating temperature the optical relay is provided with a heat exchanger which acts on the target, such that in normal operation the target has a useful central area where the target exhibits a single domain ferro-electric phase, and a neutral peripheral area at a temperature which is higher than the Curie temperature, where the target exhibits a paraelectric phase. The optical relay is used for the production of television pictures on a large screen.
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