Abstract: A cathode ray tube comprising an electron source and an electron beam guidance cavity having an input aperture and an output aperture, wherein at least a part of the wall of the electron beam guidance cavity near the output aperture comprises an insulating material having a secondary emission coefficient &dgr;1 for cooperation with the cathode. Furthermore, the cathode ray tube comprises a first electrode connectable to a first voltage source for applying, in operation, an electric field with a first field strength E1 between the cathode and the output aperture. &dgr;1 and E1 have values which enable electron transport through the electron beam guidance cavity. A second electrode is placed between the cathode and the cavity. The second electrode is connected to a second voltage source for applying, in operation, an electric field with a second field strength E2 between the cathode and the second electrode for controlling the emission of electrons.

Abstract: Picture display device having a vacuum envelope with a face plate whose inner side is provided with a luminescent screen having a repetitive pattern of triplets of red, green and blue-luminescing phosphor elements, a rear plate at a short distance therefrom and in the space therebetween a plurality of electron emitters and juxtaposed, electron ducts cooperating therewith and having walls of substantially electrically insulating material having a secondary emission coefficient suitable for electron transport for transporting, through vacuum, produced electrons in the form of electron currents. Means are provided for withdrawing each electron current at predetermined locations from its duct and for directing this current towards a desired location on the luminescent screen for producing a picture composed of pixels.

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 Electrons are withdrawn from the ducts by means of an addressing system, whereafter these electrons are directed towards desired locations on the luminescent screen.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: A picture display device has a vacuum envelope and is provided with a face plate whose inner side supports a luminescent screen, a rear wall situated at a short distance therefrom, and the space in-between accommodating a plurality of electron sources, which cooperate with a plurality of electron transport duct including dielectric walls fro transporting, through vacuum, the produced electrons towards positions at a small distance from the luminescent screen. The display device further includes means for reducing the effects of undesired charge transfer of the duct walls, which are provided to improve the start-up and/or steady state electron transport conditions. Specifically, the outer sides of the duct rear walls are provided with a conductor to which an initiation potential is applied, which is equal to or higher than the potential applied for producing the electron transport field.

Abstract: A picture display device having a flat vacuum envelope which is provided with a transparent face plate with a luminescent screen and with a rear wall, which display device has an electron supply section with an electron source for emitting electron currents in a direction parallel to the face plate, and an active selection electrode section with first, preselection, electrodes and second, fine-selection, electrodes, located closer to the screen, for directing each electron current towards desired pixels on the luminescent screen. The fine-selection electrodes are divided into groups and corresponding fine-selection electrodes of at least two groups are interconnected in a series or parallel arrangement in such a way that the technology of providing these electrodes is as simple as possible and/or the possible fine-selection electrode patterns are such that the number of required selection drivers can be reduced considerably.

Abstract: A picture display device has a vacuum envelope and is provided with a face plate whose inner side supports a luminescent screen, a rear wall situated at a short distance therefrom, and the space in-between accommodating a plurality of electron sources, which cooperate with a plurality of electron transport ducts including dielectric walls for transporting, through vacuum, the produced electrons towards positions at a small distance from the luminescent screen. The display device further includes means for reducing the effects of undesired charge transfer of the duct walls, which are provided to improve the start-up and/or steady state electron transport conditions. Specifically, the outer sides of the duct rear walls are provided with a conductor to which an initiation potential is applied, which is equal to or higher than the potential applied for producing the electron transport field.

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: The thin-type display device (1) with a vacuum envelope has a transparent front wall (3), which is provided with a display screen, and at least an electron source (5) and a duct structure, which cooperates with the electron source (5) and which extends substantially parallel to the front wall (3). Ducts (6, 6', 6") of the duct structure serve as electron-propagation means and are provided with walls (11, 11', 11") of an electrically insulating material having a secondary emission coefficient which is suitable for electron propagation. In the display device (1) 1.ltoreq.s/w.ltoreq.5 and s.multidot.w.gtoreq.5 mm.sup.2, where s is the depth of the ducts (6, 6', 6") and w is the width of the ducts (6, 6', 6"). Preferably, the width w.gtoreq.1.5 mm and the depth 3.5.ltoreq.s.ltoreq.15 mm. The voltage difference over the length of the ducts (6, 6', 6"), measured parallel to the front wall (3), is less than 75 V/cm, preferably less than 40 V/cm.

Abstract: A display device including a vacuum envelope having an electroluminescent screen, an electron source and a branched network of electron-transport ducts having at least one entrance for electrons and at least two exits at end portions of the network. An electron current flows from the entrance to a desired one of the exits via nodes in the network. The network exits corresponding to one entrance form a two or three dimensional array of exits. Preferably, the distance, via the network, between an entrance and its corresponding exits is equal.

Abstract: A flat display device is provided with a wire cathode or wire cathodes and with apertures which allow passage of electrons emitted by the wire cathode. The wire cathode is stretched in a wire-cathode support having positioning grooves for the wire cathode. This support engages the element in which the passages are made. The support and the element are provided with corresponding contacting surfaces.

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 face plate with a luminescent screen at the inner side and, arranged at a short distance therefrom, a rear plate adjoined by a large number of electron transport ducts operating by means of wall interaction of electrons. An active selection structure for directing electrons from transport ducts towards pixels on the luminescent screen comprises an apertured preselection plate and an apertured fine-selection plate, each preselection aperture being associated with at least two fine-selection apertures. Special auxiliary (or dummy) electrodes between the preselection plate and the selection plate, and/or a special geometry of the preselection apertures ensure that colour purity and contrast are maximal.

Abstract: A flat-panel type picture display device having a face plate with a luminescent screen at the inner side and, arranged at a short distance therefrom, a rear wall adjoined by a large number of electron transport ducts operating by means of wall interaction of electrons. A selection structure for withdrawing electrons from transport ducts and for directing them towards pixels on the luminescent screen comprises a preselection structure provided with preselection locations and a fine-selection plate provided with fine-selection apertures, each preselection location being associated with at least two fine-selection apertures. To improve contrast and/or color purity, an apertured obstruction plate forming chicanes in the electron paths is arranged between the preselection plate and the fine-selection plate.

Abstract: A display device comprising electron-transport ducts having entrance apertures for electrons and means for generating electrons and injecting electrons into the transport ducts via the entrance apertures. Measures have been taken to improve the picture quality. For example, the location of the entrance aperture is not the same for each transport duct, but instead shows a variation. This enables an improved control of the electron flow in the transport ducts to be achieved; in particular crosstalk between the transport ducts can be reduced.

Abstract: A display device comprising electron-transport ducts having entrance apertures for electrons and means for generating electrons and injecting electrons into the transport ducts via the entrance apertures. Measures have been taken to improve the picture quality. For example, the location of the entrance aperture is not the same for each transport duct, but instead shows a variation. This enables an improved control of the electron flow in the transport ducts to be achieved; in particular crosstalk between the transport ducts can be reduced.

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. At a given resolution, hexagonal phosphor dot patterns in which dots are horizontally staggered generally produce fewer artefacts than in a 90.degree. tilted orientation. An addressing system for withdrawing electrons from the propagation ducts and for directing them towards the luminescent screen is preferably formed as a multistepped structure with a preselection structure of rows of preselection electrodes and a fine-selection structure of rows of fine-selection electrodes. To interconnect the fine-selection electrodes in parallel in a minimal number of groups, it is advantageous when the fine-selection electrodes are arranged parallel to the preselection electrodes.

Abstract: Picture display device includes a display unit having a vacuum envelope which is provided with a transparent face plate with a luminescent screen and a rear plate. The display unit includes a plurality of juxtaposed sources for emitting electrons, a plurality of electron transport ducts cooperating with the sources and extending substantially parallel to the face plate for transporting the electrons in the form of electron currents, and an active selection structure for withdrawing each electron current at predetermined locations from its transport duct and for directing the current towards desired pixels of the luminescent screen.The picture display device further includes a video signal processing circuit for receiving an incoming video signal having a given line number, for processing the video signal to a video signal which is suitable for the luminescent screen, and for applying the processed video signal to a video drive circuit coupled to the sources.

Abstract: A picture display device having a vacuum envelope whose inner wall is provided with a luminescent screen. The device is a plurality has a of juxtaposed sources for producing electrons, local transport ducts having walls of electrically substantially insulating material having a secondary emission coefficient which is suitable for transporting, through a vacuum, electron beams, preselection means for withdrawing electrons from the transport ducts at predetermined extraction locations and for directing them towards the luminescent screen for producing a picture composed of pixels. A structure of distribution ducts having selection apertures is positioned between the transport ducts and the luminescent screen for fine selection of electrons withdrawn from the transport ducts.