Iwatsu Electric Company Ltd.

Takefumi Kato

Osamu Akizuki

Hajime Takita

Haruo Abe

Toshihiro Harada

A cathode ray tube comprises a series of quadrupolar lenses for focusing a beam of electrons, emitted from a cathode at one end of an evacuated envelope under the control of a control electrode, at a target screen at the other end of the envelope. After having been focused at the target by adjustment of electric potentials on the quadrupolar lenses, the electron beam will defocus upon change in a potential on the control electrode because then the crossover or initial focusing point of the electron beam will be displaced along the central axis of the envelope. With a view to ready refocusing of the beam at the target, a refocusing lens is provided between the crossover point and the quadrupolar lenses for providing a convering lens action of radial symmetry about the envelope axis. The beam can be refocused through adjustment of a single potential on the refocusing lens rather than through adjustment of several different potentials on the quadrupolar lenses.

Cathode ray tube having an electron gun constructed for ready refocusing

A generally box-shaped electron lens system for use in an oscilloscopic or storage cathode-ray tube for the amplification of both vertical and horizontal deflections of the electron beam from the gun to the target of the CRT. The lens system comprises two electrodes at least partly displaced from each other along the CRT tube axis, with a gap therebetween for electrically insulating one from the other. A pair of tongues extend either from the gun-side electrode into the target-side electrode, or from the target-side electrode into the gun-side electrode, or two such pairs of tongues extend from both electrodes into interdigitating relation to each other. Upon application of prescribed potentials to the two electrodes, a quadrupolar lens field is created in the space between the pair or pairs of tongues for deflection amplification in both directions. On having been deflected vertically, the beam has its deflection amplified by having its traveling direction inverted with respect to the tube axis. The beam that has been deflected horizontally has its deflection magnified without having its traveling direction inverted.

Electron lens system for deflection amplification in a cathode-ray tube

A scan converter storage tube has a storage target comprising at least two collector electrodes on a storage surface of a storage substrate. Each collector electrode has a multiplicity of parallel spaced strips which are electrically interconnected and which are arranged alternately with the strips of the other collector electrode, leaving exposed parts of the storage surface through the spacings therebetween. The establishment of a potential difference between the collector electrodes makes it possible to write information on the storage target at a high rate without necessitating an increase in an erase potential difference between the collector electrodes and the storage surface. The dual collector storage target also allows writing with a zero erase potential difference, dispensing with the erase mode preparatory to writing. There are also disclosed herein storage targets having three and four collector electrodes respectively.

Scan converter storage tube with a multiple collector storage target,

A storage target is disclosed for use in a scan converter storage tube, direct view storage tube, etc. Included are a storage substrate in the form of a single crystal of sapphire, and a collector electrode in the shape of a directional pattern on a storage surface of the storage substrate. In order to afford a high writing speed the directional pattern of the collector electrode is oriented at an angle ranging from -45 degrees to +45 degrees with respect to the projection of the c axis of the single sapphire crystal on the storage surface of the substrate. The collector electrode is preferably in the form of electrically interconnected parallel stripes extending in the direction of the projected c axis.

Storage target for storage tubes and method of fabrication

A method for ready and thorough erasure of information in a scan converter storage tube of the class including an electron gun of an electrostatic focus and deflection variety and a storage target having a substrate made from sapphire or like monocrystalline insulator. The storage surface of the substrate is first primed by a scanning electron beam from the electron gun while the potential of a collector electrode on the storage surface is set higher than the value which is lower than the potential of the field mesh electrode of the electron gun by up to about 100 volts. Then the storage surface is again scanned after setting the collector electrode potential higher than the potential of the cathode included in the electron gun and at such a value that the storage surface potential with respect to the cathode potential becomes less than a potential at which the secondary emission ratio of the monocrystalline substrate first becomes unity. Thus, as the storage surface acquires the cathode potential as a result of the scanning, a prewrite potential difference is established between storage surface and collector electrode.

Method of erasing information in a scan converter storage tube

A storage target includes a dielectric storage medium in the form of a relatively rigid sheet of insulating material having high density, such as a single crystal sheet of sapphire. A film electrode is formed, as by vapor deposition of nickel or like conductive material, on one of the surfaces of the storage medium. An array of openings are defined by and extend through the storage medium and film electrode. In some embodiments the collector electrode of a direct-view storage tube is formed on the other surface of the storage medium, also as by vapor deposition of nickel and subsequent etching.

Storage target for direct-view storage tubes

A storage target having a collector electrode formed in a striped or latticed pattern on a storage substrate which is fabricated from a single crystal of electrically insulating material. Preferably, the storage substrate is of a single rhombohedral crystal of aluminum oxide or of a single isometric crystal of magnesium oxide, spinel, or calcium fluoride.

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Hinode, Japan

Takefumi Kato