DE1165763B - Cathode ray tubes with two deflection means arranged in different planes perpendicular to the tube axis - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Kl .: HOIj

German class: 21 g - 13/23

Number:
File number:
Registration date:
Display day:

T 17841 VIII c / 21 g
February 6, 1960
March 19, 1964

The invention relates to a cathode ray tube with two perpendicular in different planes deflection means arranged to the tube axis for deflecting the electron beam in two to one another perpendicular directions, of which at least the deflecting means near the cathode has a magnetic one deflection coils arranged outside the tube wall and arranged inside the tube wall Deflection pole shoes is.

When deflecting the electron beam of a television picture tube with deflection coils through which current flows, a certain switching capacity must be applied. As is well known, the switching capacity is understood to be the product of the maximum deflection current /, and the return voltage U _R. For a given return duration, it is proportional to the product of the maximum flow rate D _1n = W ■ I _m (W = number of turns of the deflection coil) and the maximum magnetic base Φ _η . The application of the required switching power makes difficulties in particular in the case of line deflection circuits which work with transistors.

For this purpose it is already known to reduce the switching capacity by installing ferromagnetic pole pieces in the picture tube. The pole pieces can significantly reduce both the flow rate required for a specific maximum deflection angle and - given a suitable shape of the pole pieces on the side facing the electron beam - the maximum magnetic flux. It is also known, in cathode ray tubes whose electron beam is magnetically focused and has a high current density, that the part of the vacuum envelope surrounding the beam generation system is made of ferromagnetic! » Form material that this part of the vacuum envelope forms a pole piece of the magnetic focusing system. Ferrites are generally known as ferromagnetic materials, whose specific resistance is approximately ΙΟ ¹⁰ Ω and whose permeability is between 5 and 10.

The object of the invention is now to provide for the passage of the magnetic flux from the outer deflection coils in the inner deflection pole pieces of the tube required part of the flow to reduce even further.

According to the invention it is proposed that between the outer deflection coils and the inner Deflection pole shoes in the area of the passage of the magnetic flux through the tube wall in this one or more ferromagnetic bodies are inserted in a vacuum-tight manner.

Since the ferromagnetic body inside cathode ray tube with two in different
Deflection means arranged perpendicular to the tube axis

Applicant:
Telefunken

Patentverwertungsgesellschaft mb H.,
Ulm / Danube, Elisabethenstr. 3

Named as inventor:

Dr. Eberhard Gundert, Neu-Ulm / Danube,

Dr. Walter Schaffernicht,

Helmut Lotsch, Ulm / Danube

parts of the tube are close to the anode voltage and outside of the tube near the deflection coil, which is usually earth potential with DC voltage, between which voltage differences of 10 to 20 kV usually occur during operation, it is usually necessary to make the ferromagnetic body from a well insulating body Material, e.g. B. to produce a ferrite with a specific resistance of 10 ¹⁰ Ω · cm and more, the expansion coefficients of the ferrite body and the bulb glass must be matched to one another for the purpose of good fusibility.

The device described should be based on the F i g. 1 and 3 are explained in more detail.

1 shows two ferrite bodies 12 which are melted into the tube neck 11 in the region of the deflecting means near the cathode and which are brought as pole shoes close to the electron beam. With such an arrangement, the manufacture of the luminescent screen and the inner piston lining will generally be more difficult. FIGS. 2 and 2a therefore show an arrangement in which the two pole shoes are connected to the system and separated from two melted-down ferromagnetic bodies serving to carry the magnetic flux into the interior of the tube.

In the F i g. 2 and 2 a, the F i g. 2a represents a section through FIG. 2, 21 denotes the ferromagnetic pole shoes which are rigidly connected to the system structure rods 23 via tabs 22.

Further electrodes 24, 25 and 26 are attached to these system build-up bars, which are merely pure are shown schematically. At 27, the glass

409 539/377

wall of the tube in which the described ferrite parts 28 are melted.

In the arrangements according to FIGS. 1 and 2 the melted-down ferromagnetic bodies do not have any increase in the deflection required magnetic flux result. Their permeability can be as high as desired, but it is particularly effective in the case of the arrangement according to FIG. 2, there is also a permeability of the melted Body of about 10 a near optimal reduction in the required flow when the Permeability of the built-in pole pieces is higher. With high permeability of the melted ferromagnetic Body can have its cross-section and thus also the cross-section of the built-in pole pieces remain small near the implementation, whereby the weight of the pole pieces can be reduced. One can also use one to carry the magnetic flux to the built-in pole pieces closed ring made of ferromagnetic material according to the F i g. Insert 3 and 3 a into the tube neck. Then an additional magnetic flux occurs along the ring, which is created by the use of a the thinnest possible ring and a ferromagnetic material with sufficiently low permeability (from about 5 to 10) can be kept small compared to the flow required anyway for the deflection got to. The required blood flow can be reduced so far that the product is out total flow and flooding and thus the switching capacity is reduced. This effect can be supported by longitudinal grooves in the ferromagnetic ring. An improvement on this arrangement is obtained with a ferromagnetic ring, in which the permeability in the radial direction is high, but is small in the tangential direction.

In FIG. 3, the parts which are the same as the parts in the other figures are given the same reference numerals. The one melted into the tube neck ferromagnetic ring is denoted by 31. Furthermore, the outer yoke 32 is still with the Pole pieces 33 and the deflection coils 34 are shown. To have a high insulation resistance and a To obtain good vacuum tightness, it can be useful to use ferrite powder with a non-magnetic Mixing the material (e.g. glass powder) and sintering it together.

Since when the line deflection flow passes through A relatively thin and poorly conductive sheet metal only incurs low losses, one can also accordingly F i g. 4 provide 27 openings on the glass neck, which are melted on the inside of the neck Metal sheets 35 made of a suitable non-ferromagnetic material are sealed in a vacuum-tight manner and are filled on the outside by well-insulating ferrite bodies 28. The ferrite bodies can to achieve a good dielectric strength between the internally melted sheet and the outside on the tube neck arranged deflection coil (not shown) by means of a well-insulating Resin 36 or other suitable potting compound cemented into the openings on the glass neck will.

Claims (7)

Patent claims: 1. Cathode ray tube with two arranged in different planes perpendicular to the tube axis Deflection means for deflecting the electron beam in two mutually perpendicular Directions of which at least the deflecting means close to the cathode is a magnetic one with outside the tube wall arranged deflection ¹ S coils and deflection pole shoes arranged within the tube wall, characterized in that one or more ferromagnetic bodies are inserted in a vacuum-tight manner between the outer deflection coils and the inner deflection pole shoes in the region of the passage of the magnetic flux through the tube wall. 2. Cathode ray tube according to claim 1, characterized in that the (the) inserted into the tube wall (s) ferromagnetic body (s) consists of a ferrite with a specific resistance of the order of 10 ¹⁰ Ω · cm and above. 3. Cathode ray tube according to claim 1 or 2, characterized in that in the Tube neck a ferromagnetic ring is inserted vacuum-tight. its permeability approximately 5 to 10. 4. Cathode ray tube according to claim 3, characterized in that the permeability of the ferromagnetic ring is larger in the radial direction than in the tangential direction. 5. Cathode ray tube according to one or more of claims 1 to 4, characterized in that that the ferromagnetic body consists of a mixture of a ferromagnetic powder and a non-magnetic material, that is sintered together. 6. Cathode ray tube according to claim 1, 2 or 4, characterized in that openings are covered vacuum-tight in the tube neck with the help of sheet metal parts and that at least the The cavities created by the different material thicknesses are filled with ferrite parts are. 7. Cathode ray tube according to claim 6, characterized in that the ferrite parts with Help from kittens are used. Documents considered: German Auslegeschrift No. 1 005 199; Swiss Patent No. 185 511; "Frequency" magazine, Vol. 5, No. 6, June 1951, Pp. 145 to 155. 1 sheet of drawings