DE1113039B - Magnetic deflection device for cathode ray tubes - Google Patents

Description

GERMAN

PATENT OFFICE

REGISTRATION DATE: OCTOBER 2 E R 1958

NOTICE THE REGISTRATION ANDOUTPUTE

EDITED: AUGUST 24, 1961

The invention relates to a deflection device for cathode ray tubes with an electron beam enclosing, annular yoke made of ferromagnetic material on which at least one Deflection coil set is wound with at least two toroidal part coils.

In the case of deflection devices for the electromagnetic deflection of the electron beam, the difficulty arises that the deflection coils not only from the sawtooth deflection current, but also from the anode direct current of the deflection tube are traversed. This experiences the electron beam an additional deflection that must be compensated for by special centering magnets. To avoid this disadvantage is known in vertical deflection circuits, mostly in series or in parallel deflection coils connected to one another via 'eiöefl Coupling the transformer to the output tube and at the same time the necessary resistance adjustment or when connected directly to the anode circuit of the deflection tube in series with a capacitor To connect a deflection coil in parallel to this a choke. With horizontal deflection circuits For this purpose, additional windings or windings switched in opposite directions have been used so far, to compensate the anode direct current with regard to the magnetic field.

Deflection yokes are already known in which the pole shoes are used to suppress the flow of direct current of the yoke are connected by two bars, with a coil on one bar and a coil on the other on the other hand a short-circuit ring sits. The coil is powered by an alternating current superimposed on the direct current flows through, then the magnetic direct flux is short-circuited via the bridge with the short-circuit ring, while the magnetic coupling in the short-circuit ring induces a current and an opposing field is generated, so that the web with short-circuit ring has a large magnetic resistance for the Represents alternating flow.

With these deflection yokes, however, it is not possible between the time course of the deflection current and that of the deflection field to achieve absolute similarity, since for practical reasons the Resistance of the short-circuit ring is not infinitely small and its time constant is not infinitely large can be.

The above-mentioned disadvantage is avoided if, according to the invention, the partial coils of the deflection device the windings of a transformer form the secondary winding either directly or is short-circuited via a resistor.

Magnetic deflector
for cathode ray tubes

Applicant:
Telefunken

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

Friedrich Kratochvil, Hanover-Ricklingen,

and Hans Richter, Hanover,
have been named as inventors

If an alternating current superimposed on a direct current flows through one of the sub-coils, then the constant flow will close over the highly permeable toroidal core without leaving it. Due to the magnetic coupling of the two coils, an alternating flux is generated in the secondary coil Induced current, which in turn results in a counterflow in the opposite direction, whereby the Lines of force? emerge from the ring and thus form the deflection field.

Here, the anode of the end tube, z. B. the vertical deflection stage, via one of the Sub-coils connected to the operating voltage source, while the other sub-coil connected to the former is coupled via the ferromagnetic core surrounding the beam, is short-circuited. Of the The course of the field inside the cavity enclosed by the core remains unchanged, when the coil sections usually have the same copper cross-section.

For a more detailed explanation of the device described, an exemplary embodiment is given below described on the basis of the drawing. This shows in cross section the neck 1 of a cathode ray tube, which is enclosed by an annular core 2 made of ferromagnetic material. On the Core 2 are two deflection coils 3 and 4 wound in a toroidal shape, of which coil 3 is short-circuited, while the coil 4 is between the operating voltage source and the anode of a deflection tube 5

is switched, the control grid of which the sawtooth-shaped current 6 required for deflection in the usual Way is fed. The ones with such circuits

109 679/176

usual negative feedback circuits for linearizing the deflection current are to simplify the Circuit not shown, but can easily be used with this circuit will.

When a sawtooth-shaped rising current flows through the coil 4, which is transformed into the Coil 3 is transmitted, a magnetic one is formed in the usual way between the units 3 and 4 Field 7, which runs in the interior of the tube neck 1 essentially linear. As a result of the transformational Coupling of the partial coils; only the anode direct current of a partial sink can pass through the core close so that the field lines of the constant field do not emerge from the core and cause a shift of the electron beam can cause. As with the usual circuit of the deflection coils, it is also here possible to adapt the deflection coil set to the deflection tube by choosing an appropriate one To achieve transmission ratio of the two sub-coils 3 and 4. Here you can easily the primary winding high resistance and the secondary winding, d. H. the short-circuited sub-coil 3, designed with low resistance and by means of a geometry control, as shown in the drawing, automatically continuously regulating resistor 8 are loaded. To achieve a satisfactory linear To deflect it, it is only necessary to provide both coil sections with the same copper weight. When using several sub-coils, it is also possible to separate the individual secondary windings short-circuit.

The device described can not only be used in tube circuits, but is It can also be used particularly advantageously with transistors, because the deflection coils there have a very low resistance can be.

Claims (3)

PATENT CLAIMS: 1. Deflection device for cathode ray tubes with an annular yoke surrounding the beam made of ferromagnetic material, on which at least one deflection coil set with at least two toroidal partial coils is wound, characterized in that the partial coils form the windings of a transformer, the secondary winding of which either directly or via a resistor is shorted. 2. Deflection device according to claim 1, characterized in that with a direct short circuit the coil sections have the same copper weight. 3. deflection device according to claim 1, characterized in that when short-circuiting via a resistance this is an automatically and continuously regulating one. Considered publications:
German patent specification No. 810 792. For this purpose, 1 sheet of drawings © 109 679/176 8.61