DE2110459A1 - Cathode ray tube - Google Patents

Description

IH? ..- INO. IXKRUIiIiT PATZOLD 21 10459

¹ I- K .NTAN VVAI.T

8 M UXCH EX 71

H IN DELA XCJ ST R. 3 TtKLKFOK OH 11 / 7.1 77 25 TKLEQKAMM ADUESSE: I ¹ ATITlA MÜXCHEN

Nippon Electric Company, Limited 7-15, Shiba Gochome, Minato-Ku Tokyo / Japan

cathode ray tube

The innovation relates to a cathode ray tube, in particular an equipotential color cathode ray tube an electron beam generating device which, among other things, has a third which can be applied to a high voltage and fifth grid, a low potential fourth grid between the third and fifth Lattice and a & over a cup-shaped convergence device Schirnyf connected to the fifth grid and comprising the fourth and fifth grid.

Such cathode ray tubes require a high voltage for effective operation, which reaches an Ivert of up to 2.7 K ¹ / as the uppermost limit. During such operation, a discharge phenomenon often occurs between the high-voltage electrode and the low-voltage electrode, which is also referred to as "firing". This phenomenon adversely affects the screen surface and is a cause of the open circuit.

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For this reason, the cause is used to remove impurities or protrusions on the surface of electrodes for the arcing during the manufacture of the tubes generally carried out an operation that "as so-called" high-voltage treatment "or" dirt repellency " referred to as. During this operation, a higher voltage than is applied to the high-voltage electrodes the normal operating voltage is applied while the low voltage electrode is connected to earth, so that a discharge treatment going on between the electrodes.

In this high voltage treatment, a discharge phenomenon occurs between a connecting member of two high voltage electrodes and the high voltage side of the electrode, which is located between these high voltage electrodes is located. Becomes the working voltage in high voltage treatment gradually increased, the link eventually melts and is severed. For this Basically, it was previously impossible to keep the working voltage in high voltage treatment above a certain value also increase.

The object of the innovation is to provide a cathode ray tube, in particular a color cathode ray tube of the equipotential type of the type mentioned at the beginning, in which not only the arc phenomenon during normal operation is avoided after the necessary and sufficiently high voltage treatment during the manufacture of the Tube has been carried out, but at the same time the maximum of the normal operating voltage to a value can be increased significantly above that voltage of comparable conventional tubes.

The object is achieved for a cathode ray tube of the initially beaächneten type in such a way that the screen and the third grid are directly connected to one another by a connecting member.

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After the innovation, the link goes to third grid as one of the cooking voltage electrodes from the screen instead of the fifth grid thereby avoiding the proximity of the link to the fourth grid, which it is the low voltage electrode is the. between the third and fifth grids. This eliminates the discharge phenomenon between the high voltage side Link and the low voltage side - Electrode avoided during high voltage treatment. There is therefore no risk of melting and peeling of the link due to the discharge phenomenon and it is thus possible to obtain a sufficiently high To be able to carry out high-voltage treatment, which significantly improves the high-voltage stability of the tubes can be.

The innovation is described in more detail using an exemplary embodiment. In the schematic drawings shows:

Pig. 1 shows a longitudinal section through the tube foot of a conventional color cathode ray tube from Equipotential type, with an electron beam generating device by partially breaking open is visible

Fig. 2 shows a section along the lines A-A in Fig. 1 in a schematic representation and

3 shows a longitudinal section through the tubular foot of an inventive Cathode ray tube with a corresponding electrode beam generating device.

In Fig. 1 is the tube section with the electron beam suction device an equipotential color cathode ray

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tube shown, which contains a conventional screen. The beam generating device 1 consists of a cathode 2, a first grid 3 »a second grid ^, a third grid 5, a fourth grid 6, a fifth grid 7, an electric field, screen 8 and a cup-shaped convergence device 12 as the physical elements, between the cathode 2 ₃ the first grid 3, the second grid Ί, the third grid 5, a forth grid 6, and the fifth grid 7 are flat support elements 11a ... f by which the electrodes within a multi-arm glass stand 9a, 9b are kept exactly in their relative positions to each other. The cup-shaped convergence device 12 is welded to the fifth grid 7. The screen 8 against the effects of a scattered electronic field is welded to the cup-shaped convergence device 12 and the fourth grid 6 and the fifth grid 7 are located near the convergence device 12. Resilient contact arms 13 are welded to the side of the cup-shaped convergence device. Because of their elastic properties, the contact arms 13 fix and hold the beam generating device 1 within the tube neck 16 of the cathode ray tube. In addition, the contact arms are in contact with the graphite layer 1 * 1 on the inside of the glass tube neck. Thus, the resilient contact arms 13 serve as a supply line for the anode voltage to the fifth grid 7 and the screen 8 in connection with the fifth grid 7 and to the cup-shaped convergence device 12. The supply line for the third grid 5 »which belongs to the same high-voltage electrode as the fifth grid , is effected by a connecting member 10a in the form of a wire clip. However, in order to avoid contact with the fourth grid 6, the cable clip 10a is located close to one arm 9b of the glass stand 9a, 9b, as is illustrated in FIG. The leads of the cathode 2, the first grid 3 and

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of the second grid 4 in the form of lead wires 18, 19, 20 connect to the pins 17 in the tube foot 15. The aforementioned high voltage treatment for tubes with such Construction is usually done by discharging the cathode when connecting the first, second and fourth "Grid to earth and connection of the third and fifth grids to a voltage about twice as high as normal Operating voltage. In this case, a main discharge takes place between the wire clip 10a and the End face of the flat support element He of the fourth grid, and when the tension is gradually increased, it melts the conduction clip 10a often through, thereby damaging the tube. Because of this, the working voltage is the high voltage treatment of the tube relatively limited, so that the high-voltage treatment must be discontinued even if the cause for the Arcing has not yet been completely eliminated.

3 shows a cathode ray tube with an electrode construction according to the innovation. The supply line to the third grid 5 takes place through the cable clip 10b, which is connected to the surface of the screen 8 here. In such an arrangement, the conductor bracket 10b is removed from the fourth grid 6 and the support element 11, so that no discharge is caused between the fourth grid 6 and the support element II during the high-voltage treatment. There is thus no longer any possibility of melting through the wire clip 10b, so that the required high-voltage treatment can be made sufficiently high. In this way, the impurities in the electrodes and the protrusions, which are the cause of the arcing, can be completely removed ^. ithoden: jt; r; ihlrUhren dft * «In /": mf »iJ ti Afc zu ai'hMhsui,

Claims (1)

-6- 2110453 T- at: nta η s ρ τ u ο &. Cathode ray tube, in particular equipotential parabkathode ray tube, with an electron beam eye device which, among other things, has a third and fifth grid that can be applied to a high voltage, a fourth grid that can be applied to a low potential and a fifth grid connected to the screen / the fifth grid via a pot-shaped convergence device fourth and fifth grid W , characterized in that the screen (8) and the third grid (5) are directly connected to one another by a connecting member (10b). ■;