DE1206012B - Device that can be switched off to suppress the line structure in a television receiver - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. σ .:

Number:
File number:
Registration date:
Display day:

H04n

German class: 21 al -34/11

T 24019 VIII a / 21 al

May 18, 1963

December 2, 1965

The main patent relates to a disconnectable device for suppressing the line structure in a television receiver, in which the light spot of the electron beam through a permanent magnetic and / or an electromagnetic deflection system is deformed into an ellipse perpendicular to the row direction and the shutdown takes place in that the arranged on both sides of the tube neck Permanent magnets are short-circuited by a magnetic shunt or the current is interrupted or reversed in polarity in an electromagnet. The invention according to the main patent exists in that when switching the device, the electron beam is influenced so that for one For a short period of time, especially a few tenths of a second, there is no visible image on the screen or the deformation of the light spot takes place so slowly that that caused by the deformation Rotation of the image is not perceived by the observer. Preferably, during ao switching with a sliding contact to a control electrode of the picture tube for a short time Voltage applied so that the electron beam is blanked.

With the invention, the short-term application as this tension simplified.

The invention consists in that between a control electrode of the picture tube and a point more firmly Voltage that is less than the bias voltage of the control electrode, a capacitor is connected, and that the polarity of this capacitor is reversed when the device is operated with a changeover switch. The capacitor is preferably connected between the control electrode and earth. During the The time that the capacitor needs to recharge, the picture tube is then blanked.

The circuit according to the invention has the advantage that the sliding contact previously required for briefly applying the voltage to the control electrode is omitted. In the known switchover with sliding contact, when the switch is operated quickly it can happen that the picture tube, in particular when the brightness is set to high, is not darkened at all or is not darkened for long enough. In the case of the invention, the time of the blanking of the picture tube is not at all dependent on the speed of the switchover. This time is determined by the time constant that the capacitor forms with the resistors in the control path for the control electrode. By eliminating the sliding contact, the switching path of the switch can also be reduced. In a particularly advantageous disconnectable device for suppression
the line structure in a television receiver

Addendum to the patent: 1147 624

Applicant:
Telefunken

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

Named as inventor:
Hans-Günter Schulze,
Hans-Karl Kuhn, Hanover

The duration of the charge reversal of the capacitor and thus the duration of the blanking is more important depends on the brightness that has been changed in each case. The blanking is when the Line suppression is effective in the same way.

The invention is explained in more detail below with reference to the drawings.

F i g. 1 shows an embodiment of the invention; in

F i g. 2 shows the curve of the control voltage at the control electrode of the picture tube.

A picture tube 1 is controlled in terms of brightness by a video output tube 2 at the cathode. One The control electrode 21 of the picture tube 1 is connected to the grinder via resistors 22, 28 for adjustment the brightness serving potentiometer 4 connected in series with a resistor 3 between a positive operating voltage and earth is connected. The connection point 23 of the resistors 22 and 28 is connected to earth via a changeover switch 24 and a capacitor 25. The switch 24 enables it to reverse the polarity of the capacitor 25. With the switch 24, a switch 6 is coupled with the an electromagnet 5 serving to suppress the line structure via a current limiting resistor 7 can be connected to the positive operating voltage.

In the steady state, with the line suppression switched on or off, the voltage U _C25 on the capacitor 25 or the voltage on the connection point 23 or on the control electrode 21 has the positive value 26 in FIG. 2. When entering or

, -... ■ - ,. 509 740/304

Claims (1)

3 4 The line suppression is switched off with the switch in the case of the light spot of the electron beam ter 6 at the moment t0, the polarity of the capacitor 25 is reversed by a permanent magnetic and / or electrical switch 24. Since the capacitor tromagnetic deflection system initially maintains its voltage to a perpendicular 25, the ellipse standing to the line direction jumps deformed voltage at the connection point 23 to the negative 5 and the switch-off takes place by the value 27, so that the picture tube 1 is darkened. which are arranged on both sides of the tube neck with a time constant, which is given by the capacitor Neten permanent magnets by a magnet 25 and the resistors 3, 4, 28, loads see shunt short-circuited or the capacitor 25 to until the voltage at the point the current in an electromagnet falls below the positive value 26 again. The image is broken or polarized, according to patent tube 1 remains, for example during the duration D, 1147624, characterized in that dark. If the image brightness is set high, i. H. between a control electrode (21) of the picture tube of high voltage 26 at point 23 is the duration D of (1) and a point of fixed voltage, which is smaller and smaller than the bias of the control electrode (1), brightness is small. i5 a capacitor (25) is connected, and that in a practically tested embodiment of this capacitor (25) each time the invention is actuated, the switching elements have the following values of the device (switch 6) with a changeover switch: (24) polarity is reversed. Resistor 22 390 kß 2. Disconnectable device according to claim 1, resistor 3 750 kß 20, characterized in that the capacitor n.,. ,. 1 Λ, “(25) is connected between the control electrode (21) and earth resistor 4 1ΜΩ. Capacitor 25 68 nF. 3 Disconnectable device according to claim 1, characterized in that the changeover switch (24) claims: a5 ^ dem mr interruption of the current in the elec- 1. Disconnectable device for suppressing solenoids (5) serving switch (6) mechanical the line structure in a television receiver, nisch coupled. 1 sheet of drawings 509 740/304 11.65 ® Bundesdruckerei Berlin