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US 4,393,403 AGranted
Rotating diaphragm for a dynamic pick-up device having a pyroelectric layer
AssigneeU.S. Philips Corporation
InventorsHans P. Geis, Holger Helber
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AssigneeU.S. Philips Corporation
InventorsHans P. Geis, Holger Helber
Estimating the term…
By rotating a diaphragm in front of a pickup device, for example a pyroelectric vidicon, eddy currents are generated in the diaphragm if the diaphragm is made of a metal. These eddy currents are generated as a result of the interaction between the moving diaphragm and the magnetic field of the deflection coils of the vidicon. If the diaphragm is instead made of an insulating material, separation of charges occurs on it as a result electrostatic generation, due to the interaction between the diaphragm and the electrostatic field of the vidicon. Compensation of the charge separation causes interference in the video signal. According to the invention a diaphragm of an insulating material is used which is covered with a pattern of electrically conductive tracks or a very high resistance layer. As a result of this no eddy currents and no noteworthy electrostatic charges can occur, so that an interference-free video signal is obtained.
A rotating diaphragm for a pickup device having a pyroelectric target, in operation said diaphragm rotating about an axis and periodically interrupting thermal radiation which is incident on the pyroelectric target, characterized in that said diaphragm comprises:
A rotating diaphragm for a pickup device having a pyroelectric target, in operation said diaphragm rotating about an axis and periodically interrupting thermal radiation which is incident on the pyroelectric target, characterized in that said diaphragm comprises:
Dependencies are inferred from the claim text.