U.S. Philips Corporation

Pierre Dolizy

Francoise Groliere

Francois Maniguet

Photoelectric detection device comprising a vacuum chamber provided with a window having a substrate which bears a photocathode on the internal surface of the vacuum chamber is sensitive to incident light radiation between a short wavelength .lambda..sub.1 bottom threshold and a longer wavelength .lambda..sub.2 upper threshold. Electrons emitted by the photocathode are focused, accelerated and deflected by electronic means to deliver signals or an image representative of luminous events projected onto the photocathode. Window is provided with at least one light filter which determines the wavelength range for which the detection device is operational, eliminating wavelengths greater than a wavelength .lambda..sub.f such that .lambda..sub.1 &lt;.lambda..sub.f &lt;.lambda..sub.2. This light filter can be a pass-band filter which also eliminates wavelengths lower than a wavelength .lambda.'.sub.f such that .lambda..sub.1 &lt;.lambda.'.sub.f &lt;.lambda..sub.f. This filter is preferably an interference filter, arranged on the outside and/or the inside of the vacuum chamber, constituted by a series of thin layers applied to the substrate. The invention has its principal application in image dissector tubes.

Image dissector tube with light filter

A photoelectric detection structure of the present invention comprises a photosensitive layer deposited on a substrate consisting of a material transparent to radiation of visible light and of the near infrared light. The substrate has a refractive index for this radiation in the order of 2 with the substrate comprising on its surface incident to the radiation a structure to reduce the reflection of the radiation on that surface.

Photoelectric detection structure having substrate with controlled

The photoelectric device comprises a photosensitive layer on a substrate which is transparent to incident radiation. An intermediate layer for optically adapting the photosensitive layer to the substrate is provided therebetween. The respective thicknesses of the intermediate layer and the photosensitive layer are proportioned so that photon absorption takes place in the photosensitive layer near the output of the layer within a distance on the order of magnitude of the escaping depth of the electrons. Photon absorption takes place in such manner that the efficiency of the photoemission of the structure is optimum taking into account the nature of the materials of the layers.

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Ris Orangis, France

Pierre Dolizy