DE1220525B - Cathode ray tube with an electrode consisting of a metal grid and arranged transversely to the beam direction - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

HOIj

German class: 21 g -13/21

Number:
File number:
Registration date:
Display day:

S 75031 VIII c / 21g
27. Wed 1961
July 7, 1966

The invention relates to a cathode ray tube with an electrode beam deflection device, a first anode, a fluorescent screen, arranged within the tube neck, one with the fluorescent screen connected to the second anode and one consisting of a metal grid and Electrode arranged transversely to the beam direction, the potential of which is lower than the potentials of the two Anodes is.

It is an object of the invention to provide a cathode ray tube with an electron beam deflecting tube and to provide a reinforcing grid electrode which hardly emits secondary electrons.

This makes the image on the fluorescent screen of the cathode ray tube clear because none Secondary electrons emitted by the grid that amplifies and deflects the electron beam will hit the screen.

It is known that the deflection of the electron beam can be increased by attaching a metal grid in the cone of the picture tube. In this case, especially when the electron transmission factor of the grid is increased, some electron beams strike the metal of the grid, so that secondary electrons e 'are emitted. These now become free electrons in the immediate vicinity of the grid and prevent the electron beam e from reaching the fluorescent screen; rather, these secondary electrons hit the fluorescent screen, which is what is desired. Due to this disadvantage, a clear picture cannot be expected.

This disadvantage is avoided if, according to the invention, the metal grid in the vicinity of the first anode arranged electrode on the side facing the cathode with one made of glass Insulating layer is covered, the glass having a secondary electron emission factor, which is smaller than that of the metal used for the grid.

In the figure, 1 is the tube with a conical part 2 and a neck part 3. The electron gun, which is not shown here is arranged inside the tube 1 in the holding part 3. the Electron beam deflection arrangement is usually provided outside the neck part 3 of the tube 1. An electron beam e coming from the electron gun traverses the central axis of the tube is an electron beam deflecting generated by the deflection device 4 electromagnetic field.

In the tube cone, the grid electrode 5 is pre-cathode ray tube with one of one
Metal grille existing and across
Electrode arranged in the direction of the beam

Applicant:

Sony Corporation, Tokyo

Representative:

Dr. F. Zumstein, Dr. E. Assmann

and Dr. R. Koenigsberger, patent attorneys,

Munich 2, Bräuhausstr. 4th

Named as inventor:

Susumu Yoshida,

Akio Okoshi, Tokyo;

Yasuyoshi Nemoto, Kawasaki-shi (Japan)

Claimed priority:

Japan 8 August 1960 (34 398)

seen, which has an insulating layer 5 b on the side of the surface of a metallic grid 5 a, which is directed towards the electron gun. Means are also provided which ensure suitable potentials between the grid 5 and a first anode 6 and a second anode 7. In this exemplary embodiment, these means are potentiometers P ₁ , P ₂ and P ₃ , which are connected to the connection terminal of a DC voltage source S. The connection of this potentiometer is chosen so that the metal grid 5 a receives an electrical potential V which is a little smaller than a potential V _{1 of} the first anode 6, which is arranged in the neck part of the tube and is also significantly lower than the potential of the fluorescent screen , which is equal to the potential V _{2 of} the second anode 7. For example, if the first anode has an electrical potential of 5 kV and the second has a potential of 10 kV, the grid receives a potential of 4.9 kV. In order to obtain such a grid, glass is used as an insulating material, which is processed into a grid by a mechanical process. But it is also possible to use the glass of an electric

609 588/306

Subject to treatment, e.g. B. that an electron beam acts on the glass and from the thin Glass plate melts out perforations. Following this, the now Lattice-shaped glass plate, vapor-deposited metal.

The design described above makes it possible to reduce the secondary electron emission even if only part of the electron beam strikes the grid 5, so that the number of free electrons in the immediate vicinity of the grid is considerably reduced because of the insulating layer 5b.

In this way, one of the main undesirable influences which is caused by the secondary electrons e ' is eliminated.

As soon as secondary electrons occur even to a small extent, they become electrical as a result of an electrical one Field which is generated by the first anode 6 and extends over the surface of the insulating layer of the grid, accelerated by the electrical potential of this first anode and from this attracted so that they can not migrate to the fluorescent screen.

Claims (1)

Claim: Cathode ray tube with an electron beam deflection device, a first anode arranged within the tube neck, a fluorescent screen, a second anode connected to the fluorescent screen and an electrode consisting of a metal grid and arranged transversely to the beam direction, the potential of which is lower than the potentials of the two anodes, characterized in that, that the metal grid (5 a) of the electrode (5) arranged in the vicinity of the first anode (6) is covered on the side facing the cathode with an insulating layer (Sa) made of glass, the glass having a secondary electron emission factor which is smaller than that of the metal used for the grid (5 ä). Considered publications:
Landolt-Börnstein: Physikalisch-Chemische Tables, 6th edition, II / 6, p. 1007, tab. 1, and p. 1009, tab. 2. 1 sheet of drawings 609 588/306 6.66 © Bundesdruckerei Berlin