Abstract: An auto-stereoscopic display device comprises a plane viewing screen, a plane cathode, and a plane permanent magnet. A two dimensional array of rows and columns of channels extends between opposite poles of the magnet for receiving electrons from the cathode. A phosphor layer is disposed between the screen and the magnet and having a plurality of pixels each corresponding to a different channel. Grid electrode means is disposed between the cathode and the magnet for selectively controlling flow of electrons from the cathode through each channel to the corresponding pixel in response to input video data. Deflection anode means is disposed on the side of the magnet remote from the cathode for sequentially deflecting, orthogonally to the columns, each electron beam to different parts of the corresponding pixel in response to an input video clock signal.

Abstract: Raster demodulation apparatus for a raster-scanned cathode ray tube display comprises control means (400) for varying the shape of at least one scanned electron beam spot (661-663) in a direction perpendicular to scan lines of the raster. The control means (400) comprises an electro-magnet (700) for mounting on the neck of the cathode ray tube. The magnet (700) has eight pole pieces (720-790) spaced around the neck of the cathode ray tube (210). A winding (710) passes around each of the pole pieces (720-790) in succession in opposite directions so that, when an electrical current (I) is passed through the winding, adjacent pole pieces (720-790) around the neck of the cathode ray tube have different magnetic polarity to generate, within the neck of the cathode ray tube (210), a magnetic field in which magnetic lines of force (680) pass through the or each electron beam (661-663) only in a direction parallel to the scan lines of the raster.

Abstract: A vacuum electron device comprises an evacuated envelope containing a cathode for supplying electrons to form an electron beam, an anode spaced from the cathode for receiving the electron beam, and a sensor electrode located between the cathode and the anode.

Abstract: A vacuum electron device comprises an evacuated envelope containing a cathode for supplying electrons to form an electron beam, an anode spaced from the cathode for receiving the electron beam, and a sensor electrode located between the cathode and the anode.

Abstract: A display device comprises a substrate, cathode means for emitting electrons, a permanent magnet and one or more supports between the substrate and the magnet. A two dimensional array of channels extends between opposite poles of the magnet, the magnet generating, in each channel, a magnetic field for forming electrons from the cathode means into an electron beam. A screen receives an electron beam from each channel, the screen having a phosphor coating facing the side of the magnet remote from the cathode, the phosphor coating comprising a plurality of pixels each corresponding to a different channel. Grid electrode means is disposed between the cathode means and the magnet for controlling flow of electrons from the cathode means into each channel, the grid electrode means having a plurality of apertures, each aperture corresponding to one of the channels.

Abstract: A magnet for use in a magnetic matrix display has a two dimensional array of apertures between opposite poles of the magnet. The direction of the magnetic field is such that the magnet generates, in each channel, a collimating magnet field for forming electrons from a cathode into an electron beam. A `keeper`, area around the periphery of the magnet is used to improve the linearity of the field strength in the apertures from apertures at the center of the magnet to apertures at the periphery of the magnet. The `keeper`, area may have control circuits placed on the surface of that area of the magnet. The keeper area may contain apertures which are not used for collimation and into which electrons are prevented from entering by a grid electrode or by a physical blocking means.

Abstract: A display system comprises a display screen and drive means for scanning a picture onto the display screen in response to a video signal. Image scanning apparatus in the display system comprises photo-detection means optically coupled to the display screen for generating an image signal on detection of any light from the scanned picture reflected back into the display screen by an external article and subsequently internally reflected within the display screen. Storage means stores the image signal detected by the photo-detection means.

Abstract: An electron source having a cathode and a permanent magnet having perforated channels extending between opposite poles of the magnet. Each channel forms electrons received from the cathode into an electron beam for guidance towards a target. The electron source has applications in a wide range of technologies, including display technology and printer technology.

Abstract: Area cathode device for generating free electrons in a first evacuated chamber comprises a back plate; a silica glass substrate peripherally sealed to the back plate to produce a second chamber; a gas contained in the second chamber; a layer of photo-sensitive material disposed on the surface of the substrate external to the first chamber; a cathode phosphor layer disposed between the back plate and the substrate; and a pair of electrodes facing each other from opposite sides of the second chamber for energizing the gas to generate a plasma for exciting the cathode phosphor layer to generate light energy for producing electron emissions from the photo-sensitive material.

Abstract: An electron source includes a photocathode (20) for emitting electrons on excitation by incident light radiation. A permanent magnet (60) is perforated by a plurality of channels extending between opposite poles of the magnet (60). The magnet (60) generates, in each channel, a magnetic field which forms electrons received from the photocathode (20) into an electron beam for guidance towards a target (90). A shutter device (22) is provided having an array of addressable shutter elements, each selectively actuable to alternately admit and block passage of light radiation onto the photocathode (20) in response to an address signal.

Abstract: A display device comprises a cathode means for emitting electrons and a permanent magnet having a two dimensional array of channels extending between opposite poles of the magnet. The magnet generates, in each channel, a magnetic field for forming electrons from the cathode means into an electron beam. A screen receives an electron beam from each channel, the screen having a phosphor coating facing the side of the magnet remote from the cathode, the phosphor coating comprising a plurality of areas, each area being capable of illumination, at least one of the areas being capable of illumination by a plurality of the electron beams. Grid electrode means are disposed between the cathode means and the magnet for controlling flow of electrons from the cathode means into each channel, the grid electrode means comprising a plurality of elements each element corresponding to a different area of the phosphor capable of illumination.

Abstract: A method of forming an electron source having a cathode and a permanent magnet having perforated channels extending between opposite poles of the magnet. The perforated channel magnet is formed by pressing an array of pins into a moldable mass of powder confined in a mold, solidifying and magnetizing the molded mass. Electrodes may be provided at each end of the channels. Each channel forms electrons received from the cathode into an electron beam for guidance towards a target. The electron source has applications in a wide range of technologies, including display technology and printer technology.

Abstract: A display device includes a cathode for emitting electrons and a permanent magnet. A two dimensional array of channels extends between opposite poles of the magnet. The magnet generates, in each channel, a magnetic field for forming electrons from the cathode into an electron beam. A screen receives an electron beam from each channel. The screen has a phosphor coating facing the side of the magnet remote from the cathode. The phosphor coating comprises a plurality of pixels each corresponding to a different channel. A grid electrode is disposed between the cathode and the magnet for controlling flow of electrons from the cathode into each channel. A deflection sequentially addresses the electron beam from each channel to each pixel of the corresponding group. Rotational alignment APPARATUS aligns electron beams from the channels with corresponding pixels of the phosphor coating.

Abstract: A cathode ray tube display comprises a cathode ray tube (10) having a screen (11) connected to a neck portion (12) via a bell portion (13). Cancellation coil means (160,160') are arranged to receive a signal based on a scanning signal for the cathode ray tube and arranged to reduce stray magnetic fields radiating from the display. The cancellation coil means comprises a first cancellation coil (160) and a second cancellation coil (160') located on each of opposite sides of the cathode ray tube. The first cancellation coil (160) are located adjacent the bell portion and the second cancellation coil (160') being located adjacent the neck portion. The first and second cancellation coils each being contained in a plane substantially perpendicular to the screen of the cathode ray tube.

Abstract: A virtual remote cathode has the position of a space charge cloud associated with it fixed by the geometry of a fixed insulating plate. The plate can be made to accurate dimensions and hence the cathode to control grid dimension can be accurately controlled and will not change as a result of any mechanical, electrical or physical changes in the construction. The fixed insulating plate is located on a surface of the control grid facing the cathode.

Abstract: A chemically-machinable glass-magnet composition comprising a photosensitive chemically machinable glass having a magnetic material in admit therewith, wherein the photosensitive chemically machinable glass is formed of SiO.sub.2 --Li.sub.2 O--Al.sub.2 O.sub.3 containing photosensitive materials selected from silver, gold and copper and a cerium dioxide sensitizer; and the magnetic material is a Ni-Cu-Zn ferrite.

Abstract: A display system comprises a display screen including a matrix of display elements and a permanent magnet having an array of channels formed therein. Each channel corresponds to a different display element. Each display element comprises a phosphor target, an electron source and a device for controlling flow of electrons from the source through the corresponding channel in the magnet onto the target. Addressing device comprises first and second orthogonal conductors defining a grid. Each display element is located at the intersection of a different pair of first and second conductors. Each first conductor is connected to a first control electrode of the control device of each display element in a corresponding line of display elements and each second conductor is connected to a second control electrode of the control device of each display element in a corresponding line of display elements.

Abstract: An electron source having a cathode and a permanent magnet having perforated channels extending between opposite poles of the magnet. Each channel forms electrons received from the cathode into an electron beam for guidance towards a target. The electron source has applications in a wide range of technologies, including display technology and printer technology.

Abstract: A display device having a screen is provided in which a back-plate is sealed to the screen to form an evacuated chamber. An area cathode is disposed between the back-plate and the screen. A permanent magnet is disposed between the cathode and the screen. A two dimensional array of rows and columns of channels extends between opposite poles of the magnet for receiving electrons from the cathode. An anode phosphor layer is disposed between the screen and the magnet for receiving electrons from the channels. A grid electrode between the area cathode and the magnet controls flow of electrons from the cathode into the channels, whereas an anode between the magnet and the anode phosphor layer controls flow of electrons from the channels towards the screen. In a preferred embodiment, the cathode means comprises the backplate and a silica glass substrate peripherally sealed to the back-plate to produce a chamber in which a gas is contained.

Abstract: A display device includes field emission cathode apparatus for emitting electrons. A plurality of electron beams are formed from the field emission cathode apparatus. A screen, which has a phosphor coating facing the cathode receives the plurality of electron beams. The phosphor coating includes a plurality of pixels each corresponding to a different one of said plurality of electron beams. A grid electrode is disposed between the cathode and the screen for controlling the flow of electrons from the cathode. The field emission cathode includes extractor grid means, having a plurality of separately addressable portions associated with each of said plurality of pixels. A gamma transfer function between input data value and beam current is provided in order to emulate a conventional CRT. This can be achieved by use of a lookup table.