Thomson Tubes Electroniques

Yvan Raverdy

Francois Chareyre

Daniel Gally

Christian Marillat

Paul De Grott

The disclosure relates to radiological image intensifier tubes comprising a vacuum electron tube and a luminescent observation screen comprising means to improve the contrast of the image. These means consist of a layer of aluminium with a thickness of at least 1 micrometer, partially absorbent for the incident electrons, placed in the path of the electrons generated by the tube and in the vicinity of the layer of luminophores. The deposited layer has the effect of reducing, firstly, the quantity of electrons re-emitted from the observation screen to the tube and, secondly, the proportion of these electrons that return to strike the layer of luminophores. Application to radiological type image intensifier tubes.

Radiological image intensifier tube having an aluminum layer

The disclosure relates to radiological image intensifier tubes, and more particularly to means to improve the image resolution of these tubes and/or correct their brightness curve at output. The image intensifier tube comprises an input screen comprising a scintillator borne by an aluminium substrate. A porous layer of alumina is interposed between the scintillator and the substrate. The alumina layer is dyed so as to absorb the light emitted by the scintillator towards the substrate.

Radiological image intensifier tube with dyed porous alumina layer

A image intensifier tube, having its brightness curve corrected in a simple way. The image intensifier tube comprises an input window (3), and an output window (4) at which the brightness is measured. The output window (4) bears a device for the attenuation of light (20), the opacity of this device being greater in a central zone (0) than it is towards the edges (21).

Growing community of inventors

Bas Bernin, France

Yvan Raverdy