JPS62227274A - Horizontal centering adjusting circuit - Google Patents

Abstract

PURPOSE:To decide the moving direction and the moving quantity of a horizontal centering position by the polarity and the size of a current on a horizontal deflecting coil, by performing a horizontal centering adjustment by the first and the second diodes which control a variable shape inductance element and a current direction. CONSTITUTION:A horizontal centering adjusting circuit 30 is equipped with a variable inductance element 31, and the first and the second diodes Da and Db which control the direction of the current on through the element. In the inside of a follow bobbin in the variable inductance element 31, an adjusting magnetic core is loaded movably freely in the upward and downward directions, and inductances La and Lb can be varied by adjusting the position of the magnetic core. For example, when the magnetic core is moved in the right direction, it becomes La< Lb, and the current goes to ia>ib, and the mean value of the current on a horizontal deflecting coil LDY becomes positive, and it is overlapped on a horizontal deflecting current, and the horizontal centering posit ion is moved either in the right or left direction. The moving quantity in a centering is varied by the size of a centering correcting current on the deflecting coil LDY. Consequently, it is practicable to adjust a correcting current value so that the horizontal centering position is coincided with the mechanical center of a cathode ray tube.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a horizontal centering adjustment circuit suitable for application to a cathode ray tube device for terminal monitoring, etc.

[Prior Art] In a cathode ray tube device for a terminal monitor, a cathode ray tube using a deflection coil is provided with a horizontal centering adjustment means in order to align the horizontal deflection center with the mechanical center of the cathode ray tube. It is common that

The horizontal centering adjustment means may be electromagnetic or electrical.

A magnet is used as the electromagnetic means. That is, a magnet for centering adjustment is attached to the neck side of the cathode ray tube, and the position of the magnet is adjusted so that the center of horizontal deflection is located at the mechanical center of the cathode ray tube.

A horizontal centering adjustment circuit is often used as the electrical control stage. In this case, the horizontal centering adjustment circuit is connected to the horizontal deflection circuit, and the direction and direction of the direct current flowing through the horizontal deflection coil, that is, the horizontal centering correction current, is By adjusting the current 16, the horizontal deflection center is adjusted to be located at the mechanical center of the cathode ray tube.

FIG. 6 shows a conventional example.

In the figure, reference numeral 20 denotes a main part of a horizontal output circuit, and a horizontal synchronizing signal having a predetermined frequency is supplied as a switching signal to the base of a horizontal quadrant sister Qo, and between its collector and a power supply Vcc. The primary side of the flyback transformer FBT is connected. A predetermined high voltage HV is output to the secondary side.

A resonance capacitor C and a damper diode D are connected between the collector and emitter of the horizontal output quadrant sister Qo, and a series circuit of a horizontal deflection coil LDY and a three-character correction capacitor Cs is also connected.

A horizontal centering adjustment circuit 30 is connected to a connection point p between the horizontal deflection coil LDY and the three-character correction capacitor Cs.

Horizontal centering circuit 30 is shown.

It has a variable resistor R for adjustment whose both ends are connected to predetermined power supplies V+α and V−α, and its movable terminal is connected to a fixed resistor r
is connected to the connection point p mentioned above.

In this configuration, since a predetermined horizontal centering correction current flows through the horizontal deflection coil LDY via the resistors R and r, this horizontal centering correction current is combined with the horizontal deflection current (sawtooth wave current).

Therefore, by adjusting the IIf resistor R, the direction and current value of the water mocentering correction current flowing through the horizontal deflection coil LDY are changed, thereby aligning the horizontal deflection center with the mechanical center of the cathode ray tube. can be done.

[Problems to be Solved by the Invention] By the way, in the conventional horizontal centering adjustment stage described above, which uses electromagnetic means, it is possible to Since the horizontal centering position is adjusted by 181, it is not only impossible to accurately adjust the horizontal centering, but also the magnet for this adjustment causes deflection distortion.

In the case where the horizontal centering is adjusted by electrical means as shown in FIG. 6, the horizontal centering correction current flows through the variable resistor R to the horizontal deflection coil LDY, so the power loss caused by the variable resistor R is particularly high. This has the disadvantage of increasing power consumption.

In addition, since the power supply voltage applied to the variable resistor R is relatively high, it is necessary to use a resistor with high heat resistance as the variable resistor R, such as a wire-wound i1T transformer. As is well known, in a linear resistor, the resistance value is varied by the sliding of the movable element on the winding, and therefore the movable element cannot be slid smoothly.

As a result, it becomes difficult to finely adjust the resistance value, and a problem arises in that the mizuhiki L centering cannot be precisely adjusted.

Therefore, the present invention proposes a horizontal centering adjustment circuit that can solve these problems with a simple structure.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the horizontal centering adjustment circuit according to the present invention, current directions are opposite to each other at both ends of a variable inductance element for adjusting the horizontal centering position. One ends of the first and second diodes are connected so as to be oriented in the same direction, and the other ends of each of these diodes are commonly connected.

The parabolic wave voltage with a horizontal period obtained at the connection point between the horizontal deflection coil and the three-character correction capacitor is supplied to the above-mentioned variable inductance element.

[Function] In this configuration, the first diode is turned on during the positive period of the parabolic wave voltage, and the second diode is turned on during the negative period. During each on period, current flows through the horizontal deflection coil in a direction determined by the polarity of these diodes.

By adjusting the inductance of a pair of divided coils divided at the midpoint of the variable inductance element, when the horizontal period is set to a medium value, the opposite directions of the current flow to the horizontal deflection coil via the first or second diode can be adjusted. The current direction and current value of the average value of the current (hereinafter this average value current will be referred to as horizontal centering correction current) change.

The direction and amount of movement of the horizontal centering position are determined by the polarity and magnitude of the horizontal centering current flowing through the horizontal deflection coil.

[Embodiment] Next, a case in which an example of the horizontal centering adjustment circuit according to the present invention is applied to the above-mentioned terminal monitor cathode ray tube device will be described in detail with reference to FIG. 1 and subsequent figures.

In FIG. 1, 10 is a horizontal drive circuit, 20 is a horizontal output circuit, and 30 is a horizontal centering adjustment circuit according to the present invention.

In the horizontal drive circuit 10, a horizontal drive pulse S11 of a predetermined frequency is supplied to the base of the horizontal drive transistor QD. When applied to a terminal monitor, the horizontal frequency is selected to be around 53 KHz, but this is only an example.

The primary side of a horizontal drive transformer I (DT) is connected between the collector of the transistor Qo and the power supply vCC.

The horizontal periodic pulse obtained on the secondary side is supplied as a switching signal to the base of the horizontal quadrant sister Qo constituting the horizontal output circuit 20.

Since the horizontal output circuit 20 has the same configuration as described above, detailed explanation thereof will be omitted.

However, this example shows a case where the primary side of the flyback transformer FBT is connected between the emitter of the horizontal quadrant sister QO and the ground.

Horizontal deflection coil LDY1! 1: A horizontal centering adjustment circuit 30 according to the present invention is connected to the connection point P with the S-shaped correction capacitor Cs.

The horizontal centering adjustment circuit 30 includes a variable inductance element 31 for horizontal centering adjustment, and first and second diodes D a and D b that control the current direction of the current flowing through the variable inductance element 31 .

A detailed explanation of the variable inductance element 31 will be given later, but the midpoint q of the variable inductance element 31 is connected to the connection point p mentioned above.

A first diode Da is connected between one terminal 32 of the variable inductance element 31 and ground so that its anode is on the terminal 32 side.

Similarly, the other terminal 33 of the variable inductance element 31
A second diode Db selected to have a polarity opposite to that described above is connected between and ground. These diodes Da, Db
Let S be the common connection point of .

The first and second diodes Da and Db are elements for limiting the current direction.

Note that the capacitor Cx connected between the terminals 32 and 33 functions as a smoothing capacitor for smoothing the current (part of the parabolic wave current) that flows when the first and second diodes Da and Db are conductive. At the same time, it also functions as a resonance capacitor for absorbing spike noise generated when these diodes Da and Db are conductive in cooperation with the variable inductance element 31.

The inductance 31 having the configuration shown in FIG. 2 can be used.

In the figure, 40 indicates a hollow bobbin of a predetermined length, and a coil 41 is wound around the outer periphery of the bobbin with a predetermined number of turns.Both ends of the coil 41 are connected to terminals 32 and 33, respectively, and the midpoint q is connected to terminal 34.

A magnetic core 42 for adjustment is movably mounted inside the hollow bobbin 40, and by adjusting the position of the magnetic core 42, a pair of split coils 41a is formed.

Inductance La and Lb of 41b change.

Now, the operation of the horizontal centering adjustment circuit 30 in the horizontal output circuit 20 configured as described above will be explained next.

First, since the switching signal 'r''f supplied to the horizontal quadrant sister qo is a switching pulse with a horizontal period as shown in FIG. 3A, the horizontal deflection coil L
A sawtooth waveform horizontal deflection current with a horizontal period shown in FIG. 2B flows through DY. Therefore.

A parabolic wave voltage with a horizontal period as shown in C in the same figure is generated in the capacitor Cs for the 3-character correction.

Now, as shown in FIG. 3C, the first diode Da is turned on during the positive period T1 of the parabolic voltage waveform, so the first current ia flows with a waveform corresponding to the period T1 of the parabolic voltage waveform. , during the negative period T2, the second diode D
b turns on, and similarly, period T2 of the parabolic voltage waveform
A second current fb (in the opposite direction to the first current ia) flows with a waveform corresponding to . Of course, these first and second
The currents ia and ib also flow through the horizontal deflection coil LtlY.

Therefore, when the magnetic core 42 is adjusted to be located between the divided coils 4La and 41b, the inductances La and Lb of the minute-'I coils 41a and 41b are both equal. The inductance value at that time is, for example, about 200 gH.

In this adjusted state, as shown in FIG. 4A-C, the current values of the first and second currents ia and ib flowing through the first and second diodes Da and Db (in terms of horizontal period) Since the average values of the first and second currents ia and tb flowing through the horizontal deflection coil LOY become equal (hereinafter, this average value current will be referred to as a horizontal centering correction current), the average value of the first and second currents ia and tb flowing through the horizontal deflection coil LOY becomes zero.

Therefore, in this case, these first and second electric currents? Qja
, tb does not flow, so the horizontal centering position does not move.

Note that the first and second currents ia and ib are respectively connected to capacitors C! The current is smoothed by , so it becomes a direct current, but it is not a perfect direct current and has some ripple components.

The linearity due to this ripple can be suppressed to a negligible level by combining the three-character correction capacitor Cs and a linearity coil (not shown).

Now, if the /a core 42 is moved downward, for example, the equilibrium state between the inductances La and Lb will be disrupted, resulting in La (Lb).
, i b (FIG. 4D), and the current ia flowing through the horizontal deflection coil Lov.

The average value of ib is positive (E in the same figure).

As a result, the horizontal centering correction current becomes positive (current in the direction of arrow ia), and this is superimposed on the horizontal deflection current, causing the horizontal centering position to move in either the left or right direction. The centering movement jij: changes depending on the magnitude of the horizontal centering correction current flowing through the water 1L deflection coil LDY.

Therefore, it is only necessary to adjust the current value of the horizontal centering correction '1L flow so that the horizontal centering position matches the mechanical center of the cathode ray tube. Needless to say, the current value of the horizontal centering correction current can be adjusted by the magnetic core 42. stomach.

Contrary to the above, if the magnetic core 42 is adjusted so that Lb(La), as shown in FIG. 4F and G, the first and second
Since the average value of currents ia and ib is negative, a negative horizontal centering correction current (current in the direction of arrow fb) is superimposed on the horizontal deflection current. Therefore, in this case, the horizontal centering position will be adjusted in the opposite direction to that described above.

By the way, in the embodiment shown in FIG. 1, the connection point P is connected to the midpoint q of the variable inductance element 31, but as shown in FIG. The common connection point S of Da and Db may be connected to the connection point p, and the middle point q of the variable inductance element 31 may be grounded.

Even in this configuration, the horizontal centering adjustment operation is performed in the first
Since it is similar to the 2gl operation explained in the figure, the theory 1-1 is -1,1-loving.

In each of the embodiments described above, the present invention is applied to a cathode ray tube device for a terminal monitor, but it goes without saying that the present invention can be applied to any cathode ray tube device that performs electromagnetic deflection.

[Effects of the Invention] As explained below, in this invention, horizontal centering adjustment is performed using the variable inductance element 31 and the first and second diodes Da and Db that control the current direction. Therefore, compared to the conventional configuration, it has at least the following features.

First, since the horizontal centering is not adjusted by electromagnetic means, deflection distortion does not occur.Of course, it is necessary to attach a magnet for adjusting the centering 3J to the neck side of the cathode ray tube. Therefore, the configuration can be greatly simplified.

Second, since no variable resistor is used, there is no power loss caused by the variable resistor.

Thirdly, the current value of the horizontal centering correction current can be adjusted continuously to any value simply by adjusting the magnetic core 42. Therefore, the horizontal centering position t can be precisely adjusted.

From the above, the present invention can provide an on-water centering adjustment circuit that consumes less power, is inexpensive, and can be finely adjusted.

[Brief explanation of drawings]

FIG. 1 is a connection diagram showing an example of a horizontal centering adjustment circuit according to the present invention, FIG. 2 is a configuration diagram showing an example of a variable inductance element, and FIGS. 3 and 4 respectively correspond to the operation explanation of FIG. 1. Waveform diagram provided. FIG. 5 is a connection diagram similar to FIG. 1 showing still another example of the present invention, and FIG. 6 is a connection diagram showing an example of a conventional horizontal centering 31 rectifying circuit. 10...Horizontal drive circuit 20...Waterside output circuit 30...Horizontal centering adjustment circuit LDY...Horizontal deflection coil Cs...5-character correction capacitor 31...Variable inductance elements Da, Db. ...First and second diode patent applicants [1 Hon Chemi-Con Co., Ltd. Figure 4]

Claims (5)

[Claims] (1) One ends of first and second diodes are connected to both ends of a variable inductance element for adjusting the horizontal centering position so that the current directions are opposite to each other, and the other ends of each of these diodes are connected to both ends of a variable inductance element for adjusting the horizontal centering position. A horizontal centering adjustment circuit, characterized in that the parabolic wave voltage obtained at the connection point between the horizontal deflection coil and the S-shaped correction capacitor is supplied to the variable inductance element. (2) The horizontal centering adjustment circuit according to claim 1, wherein the parabolic wave voltage is supplied to the midpoint of the variable inductance element. (3) The horizontal centering adjustment circuit according to claim 1, wherein the parabolic wave voltage is supplied to a common connection point of the pair of diodes. (4) By adjusting the inductance of a pair of divided coils divided at the midpoint of the variable inductance element, the current direction and current value of the horizontal centering correction current flowing through the horizontal deflection coil can be controlled. A horizontal centering adjustment circuit according to claims 1 to 3. (5) Claims 1 to 4, wherein the inductance value of the divided coil is adjusted by adjusting the magnetic core inserted into the hollow bobbin constituting the variable inductance element. horizontal centering adjustment circuit.