Abstract: Flat-panel type picture display device having a luminescent screen and a large number of electron propagation ducts operating by means of electron wall interaction. Electrons are withdrawn from the ducts by means of an addressing system, whereafter these electrons are directed towards desired locations on the luminescent screen. An apertured spacer plate of electrically insulating material for passing electrons is arranged between the addressing system and the screen. To enable large voltage differences to be applied across the dimension of thickness of the spacer plate, the spacer plate is provided with a high-ohmic layer, or with a pattern of a low-ohmic material, or with an equalization layer at one side and with a low-ohmic layer at the other side, and at least the walls of the apertures are preferably coated with a material having a low secondary emission.

Abstract: Flat-panel type picture display device having a luminescent screen and a large number of electron propagation ducts operating by means of electron wall interaction. Electrons are withdrawn from the ducts by means of an addressing system, whereafter these electrons are directed towards desired locations on the luminescent screen. An apertured spacer plate of electrically insulating material for passing electrons is arranged between the addressing system and the screen. To enable large voltage differences to be applied across the dimension of thickness of the spacer plate, the spacer plate is provided with a high-ohmic layer, or with a pattern of a low-ohmic material, or with an equalization layer at one side and with a low-ohmic layer at the other side, and at least the walls of the apertures are preferably coated with a material having a low secondary emission.

Abstract: Flat-panel type picture display device having a luminescent screen and a large number of electron propagation ducts operating by means of electron wall interaction. Electrons are withdrawn from the ducts by means of an addressing system, whereafter these electrons are directed towards desired locations on the luminescent screen. An apertured spacer plate of electrically insulating material for passing electrons is arranged between the addressing system and the screen. To enable large voltage differences to be applied across the dimension of thickness of the spacer plate, the spacer plate is provided with a high-ohmic layer, or with a pattern of a low-ohmic material, or with an equalization layer at one side and with a low-ohmic layer at the other side, and at least the walls of the apertures are preferably coated with a material having a low secondary emission.

Abstract: An electron-beam-pumped laser includes a cathode ray tube containing a laser crystal, an electron gun for producing an electron beam including a multi-element focusing electrode layer on an inner surface of the tube for effecting focusing of the beam on the laser crystal, and a multi-element deflection electrode layer on an inner surface of the tube for effecting scanning of the beam across the laser crystal. The laser crystal is disposed on a metal heat-conductive support which is adapted for accurately positioning the laser crystal in closely spaced relationship with respect to the electron gun and to a laser light emitting window of the tube.

Abstract: Flat-panel type picture display device having a luminescent screen and a large number of electron propagation ducts operating by means of electron wall interaction. Electrons are withdrawn from the ducts by means of an addressing system, whereafter these electrons are directed towards desired locations on the luminescent screen. An apertured spacer plate of electrically insulating material for passing electrons is arranged between the addressing system and the screen. To enable large voltage differences to be applied across the dimension of thickness of the spacer plate, the spacer plate is provided with a high-ohmic layer, or with a pattern of a low-ohmic material, or with an equalization layer at one side and with a low-ohmic layer at the other side, and at least the walls of the apertures are preferably coated with a material having a low secondary emission.

Abstract: Flat-panel type picture display device having a luminescent screen and a large number of electron propagation ducts operating by means of electron wall interaction. Electrons are withdrawn from the ducts by means of an addressing system, whereafter these electrons are directed towards desired locations on the luminescent screen. An apertured spacer plate of electrically insulating material for passing electrons is arranged between the addressing system and the screen. To enable large voltage differences to be applied across the dimension of thickness of the spacer plate, the spacer plate is provided with a high-ohmic layer, or with a pattern of a low-ohmic material, or with an equalization layer at one side and with a low-ohmic layer at the other side, and at least the walls of the apertures are preferably coated with a material having a low secondary emission.

Abstract: Electrically insulating surfaces of a cathode ray tube are covered with a film of an organic material (211). This improves the high-voltage behavior of the cathode ray tube. The film is applied by a method in which a solution comprising an organic material is applied, which is allowed to dry and is subsequently caused to decompose partly.

Abstract: Electrically insulating surfaces of an image intensifier are covered with a film of an organic material. This improves the high-voltage behavior of the image intensifier. The image intensifier further has an anode hung by means of insulating rods, which rods are covered by the film.

Abstract: An electron-optical display device includes a cathode ray tube having a cylindrical neck of very small external diameter, such as .ltoreq.15 mm, the inner surface of the neck having thereon a helical multi-element layer electrode formed of a high ohmic resistance material, which electrode constitutes a focusing lens. In combination with a deflection system of correspondingly small diameter and operating at high scanning frequencies, this makes it possible to use a very small scanning spot of high luminance and without requiring excessive deflection energy. The device may be used as a television image projection tube or as an electron beam pumped scanning laser.

Abstract: Electrodes of an electron gun are etched in an electrochemical bath. The electrodes to be etched serve as the anode in the bath. The side of the electrode to be etched which faces the cathode in the chemical bath, faces an electrode at a higher potential in the assembled electron gun.

Abstract: Picture display device having a vacuum envelope with a front wall supporting a luminescent screen at its inner side and a rear wall at a short distance therefrom, connected by side walls. The envelope accommodates a plurality of adjacent electron sources and juxtaposed, local electron ducts cooperating with these sources and having walls of substantially electrically insulating material having a secondary emission coefficient which is suitable for transporting, through vacuum, produced electrons in the form of electron currents. Means are provided to make each electron current substantially travel along a particular wall of its electron duct, as well as means for withdrawing each electron current at predetermined locations from its duct and directing it towards the luminescent screen for producing a picture composed of pixels.

Abstract: Picture display device comprising a display tube with an electron gun having a hollow tubular structure with an inner surface on which a resistance structure of a material having a high electrical resistance is provided, which structure constitutes a focusing lens. The resistance structure is connected to at least two axially spaced electric contacts for connecting an anode voltage and at least one electric contact located in between for applying a focusing voltage. An electrode means of low-ohmic material for controlling the focusing lens by means of a dynamic correction signal is arranged in the region of the connection for the focusing voltage. Upon energization, the low-ohmic electrode means particularly exercises a non-rotationally symmetrical effect on the electron beam.

Abstract: The invention relates to a cathode-ray tube 1 having an electron gun 3 positioned in a neck portion 2. The electron gun 3 is provided with a focusing structure 10 which includes a hollow tube 12 of electrically insulating material. A layer 14 of a material having a high resistance is applied to the inner surface of the hollow tube. The resistance layer 14 is shielded from a getter arrangement 44 positioned in the cathode ray tube 1.

Abstract: Picture display device comprising a display tube with an electron gun having a tubular structure with an outer surface and an inner surface on which a helical resistance structure is provided in a layer of a material having a high electrical resistance for constituting a focusing lens. In the layer is also formed a coaxial correction element for generating an electric multi-pole field. The outer surface is provided with electrodes of readily electrically conducting material arranged opposite the correction element for capacitively coupling a dynamic correction signal into the correction element.

Abstract: Picture display device comprising a display tube having an electron gun with an electrostatic focusing lens for generating a focusing lens field, which tube further comprises deflection means for generating a deflection field. The focusing lens field partly overlaps the deflection field. The focusing lens comprises a tubular structure having an inner surface on which a helical resistance structure of a material having a high electrical resistance is provided, which tubular structure has a coaxial input portion and a coaxial output portion, the output portion having dimensions which prevent the deflected electron beam from impinging upon the glass of the inner wall. Correction means may be provided for correcting errors caused by the advanced position of the focusing lens.

Abstract: Picture display device comprising a display tube with an electron gun having a tubular structure with an outer surface and an inner surface on which a helical resistance structure of a material having a high electrical resistance constituting a focusing lens is provided. The outer surface is provided with an electrode of readily electrically conducting material arranged opposite at least a part of the focusing lens for capacitively controlling the focusing lens by means of a dynamically variable voltage the amplitude of which is a function of the position of the electron beam spot on the display screen.

Abstract: A display tube comprising an electron gun having a beam-shaping part and a focusing structure. The focusing structure comprises an elongate hollow structure with a high-ohmic resistive layer provided on the inner and/or outer surface and comprises means for forming a non-rotationally symmetrical lens element in the area of the focusing structure. This may be a structure generating an electric multipole (for example, dipole or quadrupole) which may be incorporated particularly in the high-ohmic resistive layer.

Abstract: Cathode ray tube having an electron gun which comprises a beam-shaping part and a focusing structure, which structure comprises a hollow tube with a helical electrically conducting glass-enamel layer on the inner surface. Together with the hollow tube, the components of the beam-shaping part are secured to axial mounting rods via metal supporting elements. The tube has a first and a second end face each of which is fixedly connected in one embodiment to a metal plate having a coaxial opening provided with a flange, which flange projects into the tube and is fused in an electrically conducting manner to the electrically conducting glass-enamel layer of the focusing structure.

Abstract: Cathode ray tube having an electron gun positioned in the neck portion, the gun comprising a beam-forming part and a focusing structure and the beam-forming part comprising at least a cathode and a metal electrode plate provided with a central aperture, and the focusing structure comprising a hollow tube of an electrically insulating material with inner and outer surfaces and with a layer of high-ohmic resistive material on at least one of the surfaces. The electrodes of the beam-forming part of the electron gun are secured via metal pins to rods for forming an assembly. The hollow tube is directly secured to the metal electrode plate for the purpose of correct alignment. The tube has a first and a second end face, the first end face in one embodiment having a metal plate with a coaxial aperture, and the said metal plate is fixedly connected to the metal electrode plate of the beam-shaping part of the electron gun in such a way that their apertures are coaxial.

Abstract: In a color display tube including an envelope, a display screen, an electron gun system for producing and focusing a plurality of electron beams directed at the display screen, and coils for deflecting the beams, convergence of the beams independently of focusing is effected by a helically wound resistive element disposed in the envelope between the electron gun system and the deflection coils. The element surrounds the electron beams and is dimensioned such that, when predetermined potentials are applied thereto, a potential gradient is produced along its length which establishes a relatively large diameter, strong convergence lens through which the beams pass.