Kabushiki Kaisha Toshiba

Takashi Awano

Shigeru Sugawara

Junichi Kimiya

Kazunori Satou

Osamu Ono

The electron gun of a cathode ray tube comprises a main electron lens portion consisting of at least four electrodes arranged in the order of first grid ( ), second grid ( ), third grid ( ) and fourth grid ( ). An intermediate first voltage and an anode voltage are applied to the first grid ( ) and the fourth grid ( ), respectively. A resistor ( ) is connected at one end to the second grid ( ) and at the other end to the third grid ( ) positioned adjacent to the second grid, with the result that second and third voltages of substantially the same potential, which are intermediate between the first voltage and the anode voltage, are applied to the second grid and the third grid, respectively. These grids are arranged such that a second electrostatic capacitance between the second and third grids ( ) is smaller than any of a first electrostatic capacitance between the first and second grids ( ) and a third electrostatic capacitance between the third and fourth grids ( ). As a result, the lateral collapse phenomenon of the electron beam, which is brought about in a periphery of the screen by the difference in the lens magnification between the horizontal direction and the vertical direction, can be moderated, (making it possible to provide a cathode ray tube having satisfactory image characteristics over the entire region of the screen.

Cathode ray tube

In the electron gun assembly of a cathode ray tube, a main electron lens portion is formed by a fifth grid to an eighth grid, and incorporates a quadrupole lens. The fifth grid receives a voltage obtained by superposing, on a voltage as a reference voltage, a dynamic voltage that parabolically changes with an increase when the electron beam is deflected amount of the electron beam. The sixth grid receives a voltage obtained by superposing, on a voltage as a reference voltage, a dynamic voltage that parabolically changes with an increase when the electron beam is deflected amount of the electron beam. The seventh grid receives the voltage, while the eighth grid receives an anode voltage.

Cathode ray tube apparatus including an electron gun assembly capable of dynamic astigmatism compensation

An electron gun assembly of a cathode ray tube has a main electron lens section comprising at least four electrodes, provided in a sequence of first, second, third and fourth grids, a middle first voltage is applied to the first grid, and an anode voltage is applied to the fourth grid. The adjacent second grid and third grid are connected by a resistor, and second and third voltages of substantially the same potential, corresponding to voltages higher than the middle first voltage and lower than the anode voltage, are applied thereto. An asymmetrical lens is provided between the adjacent second grid and the third grid second lens region, and a voltage which changes in synchronism with the deflecting magnetic field is applied to the first grid. Therefore, it is possible to provide a cathode ray tube wherein a phenomenon of sideways deviation of an electron beam at the peripheral region of a screen caused by lens magnification difference in the horizontal and vertical directions is reduced, and which has good image characteristics in all regions of the screen.

Cathoderay tube

An electron gun assembly includes a plurality of cathodes arranged in an in-line direction, at least first through fourth grids having electron beam passing holes arranged in an in-line direction, and an insulation support for sandwiching the cathodes and the grids between and fixing the cathodes and the grids from a direction perpendicular to the in-line direction. The second grid and the fourth grid are supplied with substantially the same low potential, the third grid is supplied with a potential higher than the potential of the fourth grid, and the second grid is fixed to the insulation support on a side of the third grid. The third grid has a cup-shaped electrode on a side of the second grid, the cup-shaped electrode including a plane portion having electron beam passing holes, an opening portion, and planting portions planted in the insulation support.

Electron gun structure

An inline type electron gun assembly has a main lens for focusing three electron beams on a phosphor screen. A resistor is arranged in a cathode ray tube. A voltage obtained by dividing a high voltage with the resistor is applied to an intermediate electrode. Voltages of a focusing electrode, the intermediate electrode, and a final accelerating electrode that constitute the main lens are determined to increase sequentially. Electron beam holes in the intermediate electrode on the focusing electrode side, and electron beam holes in the intermediate electrode on the final focusing electrode side form vertically elongated holes longer in the vertical direction than in the horizontal direction. Electron beam holes in the focusing electrode on the intermediate electrode side and electron beam holes in the final accelerating electrode on the intermediate electrode side form open holes having no side wall portions. A color cathode ray tube having an electron gun assembly capable of improving resolving power can be provided.

Growing community of inventors

Fukaya, Japan

Takashi Awano