JPS6199487A - Convergence or beam spot correcting circuit - Google Patents

Abstract

PURPOSE:To form a beam spot to an approximately perfect circle throughout a screen by flowing an approximately sine wave current of a horizontal period subjected to current clamping to a correcting coil and flowing a prescribed current of a vertical period to the connection point from the external to control the quantity of current clamping and correcting the beam spot. CONSTITUTION:When the current supplied to a vertical period current input terminal 18 is zero, an approximately sine wave correcting current of a horizontal period H which is maximum of positive side nearly at center of the horizontal scanning period and is zero on both sides is flowed to a correcting coil 11. Consequently, the quantity of current clamping of the approximately sine wave correcting current of the horizontal period which is flowed to the correcting coil 11 can be controlled by a correcting current of a vertical period V supplied to the vertical period current input terminal 18, and the beam spot is corrected throughout a screen 17. For example, when the beam spot on the screen distorted vertically long in the upper part, the lower part, and the center of a screen 17 of a color picture receiver is corrected, a parabolic current (i) of the vertical period V having the characteristic opposite to that of the current shown in a figure A is supplied to the vertical period current input terminal 18.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a convergence or beam spot correction circuit for correcting a beam spot on a screen of a color picture tube.

[Conventional technology]

For example, a color picture tube has one gun and three beams, and in a color picture tube with three beams, an electrostatic deflection plate is used to adjust the horizontal electrostatic convergence, and a cap is installed on the outside of the neck of the electrostatic deflection plate as shown in Figure 4. Dynamic convergence correction can be adjusted by arranging two sets around a letter-shaped convergence yoke and supplying a horizontal periodic current (or sine wave current) to a correction coil ◇■ wound around this yoke. I'm doing K.

In-line color picture tubes also have a vertical barrel shape,
Since the shape of the beam spot is distorted due to the use of a horizontal pincushion-shaped deflection magnetic field, which reduces the resolution, a correction yoke is provided on the outside of the neck portion to correct this, as shown in Figure 4, and the beam spot is wound around this. A horizontal parabolic current (or sine wave current) is supplied to the correction coil α~. Supplying horizontally periodic correction currents to these correction coils (11) is nothing but setting the correction amount at the center of the screen to zero and increasing the correction amount toward the periphery. By the way, since the horizontal period correction current is formed based on the horizontal Nockles voltage taken out via the horizontal output quadrangle, it generally does not contain a DC component. Therefore, in the central part of the screen, the opposite correction is made to the peripheral part, which is not originally necessary. For example, in the conventional color picture tube that performs horizontal electrostatic convergence using an electrostatic deflection plate as described above, this unnecessary correction is canceled out by horizontal electrostatic comparance correction. In addition, in picture tubes that do not adjust horizontal static convergence using an electrostatic deflection plate, superimposing a variable DC current from an external DC power supply on the horizontal cycle current for correction causes the unnecessary noise that occurs at the center as described above. I tried to cancel the correction.

According to such a conventional configuration, each time the dynamic convergence or beam spot correction at the periphery of the screen is adjusted, it is necessary to readjust the horizontal static convergence etc. so that the amount of correction becomes zero at the center of the screen. , the adjustment operation was complicated.

Therefore, even when the amount of correction at the periphery of the screen is changed, the amount of correction at the center of the screen remains unchanged, so that the above-mentioned drawbacks can be eliminated as shown in Figure 5. 59-7270).

That is, in FIG.
), a negative Noyals voltage with a horizontal period as shown in FIG. 6A is generated on the high potential side (point A).

The high potential side of the secondary winding (2) is connected to an equinox circuit in which a coil (3), a series circuit of a capacitor (4) and a variable resistor (5) are connected in parallel, and the output (B point)
A sawtooth voltage shown in FIG. 6B is generated.

This sawtooth wave voltage is supplied to the pace of the npn type transistor (6) through a parallel circuit of a capacitor and a resistor, and the transistor (6) is switched by the sawtooth wave voltage.

The emitter of the transistor (6) is grounded, and its collector is connected to the power supply terminal (10B) via the choke coil (7) and variable resistor (8), and a damper J is connected between the collector and the ground. ? - A parallel circuit of diode (9) and capacitor αQ is connected. The variable resistor (8) has one end of its stator open and its slider connected to the power supply terminal (10B) to which positive DC voltage is supplied. The voltage supplied to the other circuit is varied.The collector (point C) of this transistor (6) is connected to the transistor (point C) via the choke coil (7) when the transistor (6) is turned off. The current flowing through the choke coil (7) and the capacitor (<11) now flows into the capacitor (<11), so the horizontal period is wide (30
A pulse voltage with a pulse width of approximately μ8 is generated.

Further, αyu indicates, for example, a correction coil wound around a yoke for convergence correction. As shown in Fig. 4, two correction yokes are provided in a U-shape, and a correction coil is wound around each of them, but the correction coil U is a combination of the correction coils of each yoke. The first series circuit is interrupted by the coil <11) and the first diode (6), and the dummy coil (2) with an inductance value approximately equal to that of the correction coil (11) and the first diode (0) A second series circuit is formed by a second diode (I4) with opposite polarity, these first and second series circuits are connected in parallel, and one end of this parallel circuit is connected to one end of the DC power supply. The other end is connected to the collector of the transistor (6) through a capacitor (T).1, the correction coil α force or the inductance value of the dummy coil (2) of the Hachiyoke coil (7) Compared to that, this correction coil α or dummy coil (6
) and the capacitor (g) are selected so that the series resonance frequency is approximately equal to the horizontal frequency. Furthermore, when these diodes are cut off, between the connection point of the correction coil Ql) and the diode (2) and the connection point of the dummy coil Q3 and the diode (2), the correction coil α force or the dummy coil (2) is connected. ) A capacitor aQ is inserted to protect these diodes against the back electromotive force generated in the diodes. In this case, a capacitor may be connected in parallel between the anode and cathode of diode (2) and q/9, respectively, but since one diode is always in a diode, it is only necessary to connect one capacitor αQ. And the diode's hosai Nanashiro. Moreover, since the capacitance value of this capacitor QQ is sufficiently smaller than that of the capacitor port →, it has almost no effect on the resonant operation of the correction coil α or the dummy coil 0 and the capacitor (A).

In the configuration of the conventional example described above, the pulse voltage with the horizontal period shown in FIG. Therefore, the diode (2) and α→ are turned on alternately, and a sine wave current with a horizontal frequency flows as a whole.
One dummy coil αJ has a maximum positive value at both 9' and 11 of the horizontal scanning period, and approximately at the center, as shown in Figure 6, when the direction indicated by D in Figure 5 is positive. A current with a substantially sinusoidal horizontal period of zero flows. The other correction coil α■ has a maximum positive value approximately at the center of the horizontal scanning period, as shown in FIG. 6, when the direction indicated by E in FIG. A correction current with a substantially sinusoidal horizontal period that becomes zero flows.

In addition, FIG. 6F shows the collector current waveform of the transformer 7 star (6), and the DA/.000 current caused by the DAN/SO diode (9) is shown in broken lines in the same figure.

Furthermore, the waveforms in Figure 6 C and F are slightly out of phase with respect to the center of the horizontal scanning period, but this can be arbitrarily determined by setting the resonant constant ridges of the choke coil (7) and capacitor 1.1q as described above. Therefore, it is of course possible to set it to coincide with the center and heel portions.

As is clear from the above, according to this conventional example, dynamic convergence correction is adjusted by adjusting the chill (TILT)Nu by the variable resistor (5) and the amplifier (AMP) by the variable resistor (8). Even if this is done, the correction current shown in box E is always zero on both sides of the screen, so there is no need to readjust the static convergence correction etc. while adjusting the dynamic convergence correction, and the adjustment work is extremely simple. Simplified fossils are profitable. This also applies to the case where distortion of the shape of the beam spot due to the deflection magnetic field is corrected. In addition, when a variable DC current is used as a correction current using an external 8 DC power supply, loss occurs in the correction current blocking coil of the horizontal period necessary for superimposition, and if the correction amount by the variable DC current is large. for,
The voltage or current of the external DC power supply was very low. However, according to this conventional example, there is no need to add any direct current to the correction current, so efficiency can be improved. In addition, as in the conventional example described above, if a loop voltage is used for a node with a wide pulse width close to 1 of the horizontal period in a switching circuit consisting of 7 transformers (6), etc., a horizontal deflection circuit with a narrow node 1 width can be created. Compared to direct use of flyback pulses, it is more efficient because it contains more of the fundamental wave component of the horizontal frequency sine wave. Furthermore, it is conceivable to form a correction current and then clamp it so that the value on both sides of the screen becomes 4, but in this case, since the correction coil is a load, 1. Such a disadvantage would arise that the configuration of the clamp circuit would be very complicated, but in the example shown in FIG. 5, clamping is performed at the same time as the correction current is generated, so this disadvantage does not occur.

[Problem that the invention seeks to solve]

However, in the convergence or beam spot correction circuit shown in FIG. 5, the correction is made uniformly from the top to the bottom of the screen of the color picture tube, so for example, the top, bottom and center of the screen are corrected uniformly. In correcting the beam spot with respect to the beam spot, an inconvenience arises when attempting to perform optimal correction.

In other words, on the screen (1't) of a color picture tube, the beam spot is generally distorted horizontally at the left and right corners of the upper and lower parts, and vertically at the center of the center, as shown in Figure 7. I'm here. When it is 0, the beam response is lower than when the beam spot is a perfect circle, and the resolution is degraded. When this case is corrected using the correction circuit shown in Figure 5, it is necessary to change the clamp position of the current at the top and bottom of the screen and the center part, but with this conventional correction circuit, the current is fixed uniformly from the top to the bottom of the screen. When the central part is optimally corrected, the upper and lower beam spots are either not improved at all or are even worse.

In view of this, an object of the present invention is to provide a convergence or beam spot correction circuit that can make a beam spot substantially circular over the entire screen.

[Means for solving problems]

According to the present invention, the convergence or beam spot correction circuit has a two-capacitor (
g), convergence or beam spot correction coil α
A dummy coil (to) with an inductance value equal to that of the correction coil αρ is connected in parallel to the series circuit of the correction coil αυ and the diode (6), and this capacitor ( A) and the correction coil (1) are made to resonate in series with a horizontal period, and a current-clamped approximately sinusoidal current with a horizontal period is passed through the correction coil (11), and the correction coil (11) and the diode (B) are A predetermined current with a vertical period is applied to the connection point from the outside to control the amount of current clamping, thereby correcting the beam spot over the entire screen.

[Effect]

According to the present invention, a substantially sinusoidal current with a horizontal period, which is current-clamped to the force of the correction coil α, is passed through the correction coil α.
Since a predetermined current with a vertical period is injected from the outside into the connection point with the diode (2), the amount of current clamping can be well controlled over the entire screen by the predetermined current with a vertical period from the outside. This allows the beam spot to be corrected over the entire screen.

〔Example〕

Hereinafter, one embodiment of the convergence or beam spot correction circuit of the present invention will be described with reference to FIGS. 1, 2, and 3. In FIG. 1, parts corresponding to those in FIG. 5 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In this example, the collector of a switching transistor (6) is connected to a power terminal B to which a positive predetermined voltage is supplied via a choke coil (7), and the collector of this transistor (6) is connected to a capacitor α. →, ground through a series circuit of compar sense or beam spot correction coil αυ and clamping diode (2), and connect the connection point of this capacitor (b) and this six correction coils to this correction coil. It is grounded via a dummy coil (6) with an inductance value equal to the inductance value. In addition, a capacitor C1 for preservation is connected in parallel to the diode (b). In this case, diode (2) α◆ in Figure 5
If one of them is provided, for example, if a diode (2) is provided as shown in Fig. 1, the correction coil 0]) → diode (2)
)→Since it forms a closed circuit with the dummy coil (2), DC regeneration can be performed.@Also, frame a indicates a predetermined current with a vertical period V from the outside, for example, a para day with a vertical period ■ as shown in FIG. This vertical periodic current input terminal α→
is connected to the base of pnp transistor 4 through a capacitor (to), and the base of
Connect the emitter of this transistor wire to the power terminal B through the resistor (C), and connect the base to the power terminal B through the resistor (C). , the collector of this transistor (A) is connected to a correction coil Q1) and a diode (6) via a resistor.
) connection point. The rest of the structure is the same as that shown in FIG.

In this example, when the current supplied to the vertical periodic current input terminal is zero, the correction coil α force has a value approximately at the center of the horizontal scanning period as shown in FIG. 6E, as in FIG. A correction current having a horizontal period H in the form of a substantially sinusoidal wave flows, which reaches a positive maximum at , and becomes zero on both sides thereof. Therefore, in FIG. 1, the same effect as in FIG. 5 can be obtained, and in addition, the correction current with the vertical period V supplied to the vertical period current input terminal α frame flows through the correction coil α■. It is possible to control the amount of current clamping of the correction current having a substantially sinusoidal horizontal period as shown in FIG.

For example, as shown in Fig. 7, the screen of this color picture tube (1f
), the upper and lower left and right corners are distorted horizontally,
When correcting the beam spot of a screen that is vertically distorted in the center of the screen, a parabolic current with a vertical period V of opposite polarity to the current shown in Fig. 2A is applied to this vertical periodic current input terminal α frame. The connection point between the correction coil α and the diode (6) is zero at the center of the vertical period V, as shown in FIG. A parabolic current ff1l is applied so that it is zero at , and maximum at its upper and lower ends. In this case, the approximately sinusoidal correction current flowing through the correction coil α■ with a horizontal period H has a vertical period V supplied to the connection point between the correction coil (b) and the diode (6) in the center of the screen a. Since the correction current il is zero, as shown in FIG. 2B and similar to FIG. The beam spot becomes a circle, and the correction current is zero on both sides of the horizontal scanning period, so that the beam spot is not corrected and maintains a perfect circle. In addition, at the upper and lower ends of the screen (b), the correction current i1 with the vertical period (■) supplied to the correction coil H and the contact α of the diode (6) is at its maximum, and this correction current (
1 determines the amount of current clamping, and this correction coil C
As shown in Fig. 2C, the horizontal period correction current flowing through 1υ is approximately sinusoidal with a horizontal period that is zero at the center of the horizontal scanning period and reaches a negative maximum on both sides. Each beam spot is corrected to become a perfect circle, and the beam spot at the center of the upper and lower ends is not corrected and maintains a perfect circle.

The beam spots at other points on the screen (6) are similarly corrected, and as shown in FIG. 3, the beam spots are corrected over the entire screen to become a perfect circle, thereby improving resolution and the like. Even if the beam spot on the screen (b) is not as shown in Fig. 7, by selecting the current with a vertical period V to be supplied to the vertical period current input terminal (g), the beam spot can be created over the entire screen in the same way. can be corrected.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations can be made without departing from the gist of the present invention.

〔Effect of the invention〕

According to the present invention, a substantially sinusoidal current with a horizontal period, which is current-clamped, is passed through the correction coil α, and an arbitrary correction current with a vertical period is applied externally to the connection point between the correction coil α and the diode (6). Therefore, the amount of current clamping of the approximately sinusoidal current having a horizontal period can be well controlled over the entire surface of the p-screen by using an arbitrary correction current having a vertical period from this external source.
This has the advantage of being able to perform good beam spot correction over the entire screen.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an embodiment of the convergence or beam spot correction circuit of the present invention; FIGS. 2, 3, 6, and 7 are diagrams for explaining the present invention; and FIG. The figure is used to explain an example of a convergence yoke or a beam spot correction yoke, and FIG. 5 is a connection diagram showing an example of a conventional convergence or beam spot correction circuit. (1) is a horizontal suspension quadrence, (6) is a switching transistor, α is a correction coil, (2) is a diode, (13 is a dummy coil, (6) is a capacitor, a → is a vertical periodic current input terminal, The wire is a transistor. Figure 5 Figure 6

Claims (1)

[Claims] A series circuit of a capacitor, a convergence or beam spot correction coil, and a diode is connected between the output terminal of the switching transistor that is intermittent in a horizontal period and one end of the DC power supply, and the series circuit of the correction coil and the diode is connected in parallel with the above. A dummy coil with an inductance value equal to that of the correction coil is connected in parallel, and the capacitor and the correction coil are caused to resonate in series with a horizontal period, and a substantially sinusoidal current with a current clamped horizontal period is passed through the correction coil. A convergence or convergence device characterized in that a predetermined current with a vertical period is applied from the outside to the connection point between the correction coil and the diode to control the amount of the current clamp, thereby correcting the beam spot over the entire screen. Beam spot correction circuit.