Thomson-csf

Thomson Tubes Electroniques

Gerard Vieux

Paul De Groot

Henri Rougeot

Francois Chareyre

Jean-Luc Ricaud

Francis Diaz

Didier Monin

Gilbert-Rene Colomb

Yves Raverdy

Alain Tranchant

Daniel Boisson

Paul De Croot

Disclosed is a improvement in the fabrication of a scintillator, notably for the input screen of an X-ray image intensifier tube. According to the disclosure, the substrate on which a layer of scintillating material such as cesium iodide deposited in is made to grow is subjected to a treatment resulting in the formation of an alveolate structure or surface state, the consequence of which is the formation of thinner needles. The reduction of the mean diameter of the needles results in a improvement of the resolution of the device.

Method for the fabrication of a scintillator and scintillator obtained

An input screen scintillator for an X-ray image intensifier tube. The tube includes light conductive cesium iodide needles formed on an electrically conductive substrate. Each needle is entirely coated with a material such as a metal or a semiconductor which reflects the light travelling within the needle toward the inside of the needle. This coating can enhance the efficiency and resolution of the image intensifier tube.

Input screen scintillator for an X-ray image intensifier tube and

An image intensifying tube, such as a image intensifying tube which converts X-rays into a visible image, comprises a curved input screen which comprises a substrate that receives input radiation and a photocathode supported on the substrate, and an output screen which converts the electrons emitted by the photocathode into a visible image. In order to compensate for changes in luminosity due to the curvature of the input screen, an intermediary layer of radially variable thickness is deposited between the substrate and the photocathode. The intermediary layer is made from a material, such as indium oxide (In.sub.2 O.sub.3), which modifies the electron emitting characteristics of the photocathode as a function of the thickness the intermediary layer. Thus, a thicker intermediary layer near the center of the input screen will compensate for reduced luminosity at the edges of the screen.

Input screen of a radiographic image intensifying tube having a radially

The disclosure concerns television cameras having an image pick-up electron tube. The signal input plate of the tube according to the invention is made by molding and a connection pin is embedded in the glass during the molding operation itself. When the internal and external faces of the input plate are then polished, the end of the pin on the internal side of the pin is levelled down at the same time. All that remains to be done then is to deposit a transparent conductive layer and a photoconductive target on this perfectly plane face. Furthermore, the unpolished edges of the input plate and, more particularly, its lateral edges are covered with a light-absorbing black layer which is produced not by the deposition of a black paint but by chemical reduction of the metal oxides contained in the glass. This blackening is preferably obtained during the molding operation itself, by placing the mold in a hydrogen-reducing atmosphere.

Image pick-up electron tube with molded signal input plate and

An improved scintillator for an input screen of an X-ray image intensifier tube is disclosed which has a substrate on which there is deposited the scintillating material in the form of thin parallel needles. The face of the substrate having the scintillating materials has an alveolate surface state or has an alveolate structure. As a result of this structure there are thinner needles formed and the reduction in the diameter of the needles results in an improvement of the resolution of the device.

Scintillator with alveolate structured substrate

The invention concerns an input screen scintillator for an X-ray image intensifier tube. This tube comprises light-conductive cesium iodide needles formed on an electrically conductive substrate. According to the invention, each needle is entirely coated with a material such as a metal or a semiconductor which reflects the light travelling within the needles and allows an identical potential level in the coating material as in the substrate towards the inside of said needles. The coating can enhance the efficiency and resolution of image intensifier tubes. The invention has applications in the field of X-ray imagery.

The invention concerns a manufacturing process of a photocathode for an image intensifier tube. According to this process, the photocathode is made within the tube by depositing a photoelectric material on a conductive substrate by vacuum evaporation. During this operation, the optical transparency of the deposit is checked by illumination of this deposit by a light source. According to the invention, this light source is located within the tube and is protected from the vapors of the photoelectric material. In the prior art, this light source was located outside the tube and the illumination of the deposit was not sufficient. The invention has applications in the field of image intensifier tubes.

Manufacturing process of a photocathode for an image intensifier tube

Before being introduced within the intensifier, the grid which is nearest the anode is coated with a layer of electrically conductive material having the property of oxidizing alkali metals. This has the effect of elininating any parasitic illumination of the viewing screen caused by alkali metals unintentionally deposited on the grid at the time of formation of the photocathode.

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Grenoble, France

Gerard Vieux