JPS6218888A - Convergence correcting device - Google Patents

Abstract

PURPOSE:To correct a residual convergence pattern nearly over the entire screen by producing a hexapolar magnetic field in the neck of an image receiving tube with a correcting current obtained by superposing the current obtained by modulating a parabolic wave in a horizontal deflection period by a vertical deflection period a parabolic wave in a horizontal deflection period upon a vertical deflecting current. CONSTITUTION:A horizontal deflection output means 12 generates a saw-tooth horizontal deflection current IH and supplies it to horizontal control windings 11b and 11c of a saturable reactor 11. The correcting current I is generated by the saturable reactor 11, a coil L, and a capacitor C by superposing the parabolic wave current in a horizontal deflection period on the vertical deflecting current IV and flowed to coils 6a and 6b. Here, the level of the vertical deflecting current IV flowing to a vertical control winding 11a is adjusted properly by a variable resistance 9 and the winding ratio of the vertical and horizontal control windings 11a, and 11b and 11c is selected properly to generate the correcting current I from which a vertical deflection current component is almost removed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a convergence correction device, and more particularly to a convergence correction device for correcting a residual convergence pattern due to coma aberration in a self-convergence type color picture tube having an in-line electron gun. .

Conventional technology Conventionally, self-convergence type electron guns for blue (B), green (G), and red (R) are arranged in a row in the horizontal scanning direction inside the neck of the receiving tube. There is a color picture tube.

In such color picture tubes, convergence is achieved by appropriately adjusting the deflection yoke to change the vertical deflection magnetic field to a barrel magnetic field and the horizontal deflection magnetic field to a bottle cushion magnetic field. However, complete convergence cannot be obtained only by the magnetic field generated by the deflection yoke of the color picture tube, and as is well known, a residual convergence pattern as shown in FIG. 4 occurs. That is, a convergence shift occurs between the red and blue beam rasters R, B and the green beam raster G due to so-called coma aberration.

Conventionally, in order to correct the residual convergence pattern, for example, as shown in FIG. , 3b. This is done by suppressing the rear leakage magnetic field of deflection yaw for the blue and red beams by the field controller 3a, and by increasing the leakage magnetic field for the green beam by the field controller 3b, the coma aberration is corrected. It is something.

Further, as another residual convergence correction means, there is a method of generating a six-pole magnetic field near the neck 1, as shown in FIG. That is, coils 5a to 5d are wound around E-shaped cores 4a and 4b arranged symmetrically with respect to neck 1,
And the coil 5a.

5b and the coils 5c and 5d are connected so that their respective winding directions are opposite to each other. Here,] 5a to 5d
A vertical deflection current Iv is flowing in the , and when a current 1v flows in the direction shown in FIG. A six-pole magnetic field is generated. In this case, the blue and red beams B
, R are deflected downward under the action of electromagnetic forces Bs and Rs.

Further, when the current 1V flows in the opposite direction to that in FIG. 6, the blue and red beams B and R are deflected upward.

In this way, the residual convergence pattern shown in FIG. 4 can be corrected.

Problems to be Solved by the Invention However, in both cases of the coma aberration correction method using the doma field controller and the hexapole magnetic field, the center beam (green beam G) and side beams (blue and red beams B)
, R), and when the correction of comatic aberration on the vertical axis F of the screen is optimized, a convergence shift occurs in which the center beam shifts inward at the corner of the screen as shown in Figure 7. (hereinafter referred to as "green droop") occurs.

In addition, in order to partially minimize the range of convergence deviation in this case, as shown in Figure 8, the coma correction is overcorrected on the vertical axis of the screen, and the side beam of the center beam at the corner of the screen is A method is used to minimize the amount of deviation from the However, the above method also has a problem in that it is not possible to completely correct the convergence shift at the corner of the screen.

Therefore, the present invention solves the above problem by passing a correction current obtained by superimposing a current obtained by modulating a horizontal deflection synchronized parabolic wave with a vertical deflection period on the vertical deflection current through the coil that generates the six-pole magnetic field. The purpose of the present invention is to provide a convergence correction device that solves the problem.

Means for Solving the Problems This Invention] The interference correction device uses a modulated current obtained by modulating a parabolic wave with a horizontal deflection period with a vertical deflection period, or a current obtained by superimposing a vertical deflection current on the modulated current. and means for generating a hexapole magnetic field in the neck of the picture tube in accordance with the correction current to which the supplementary iE current is supplied.

Effect The correction current has a larger current value when the electron beam is deflected toward the periphery of the screen than when it is deflected toward the center of the screen. Furthermore, the six-pole magnetic field acts on the side beams, as is well known.

Therefore, while keeping the green beam raster substantially constant, the blue and red beam rasters are corrected by a six-pole magnetic field corresponding to the correction current, thereby making them coincide with the green beam raster.

Embodiment FIG. 1 shows a circuit diagram of an embodiment of the convergence correction device according to the present invention. In the figure, coils 6a and 6b are the coils 5a shown in FIG. 6, respectively.

5b, 5c, and 5d, and are coils for generating a six-pole limit in the neck 1 as described above by the flowing current.

In FIG. 1, the vertical deflection output stage 7 generates a sawtooth vertical deflection current [v which is transmitted to the neck of the picture tube (not shown).
A vertical deflection coil 8a mounted on the vertical deflection coil 8a.

8b to deflect the image receiving screen in the vertical direction, and also supplied to the variable resistor 9. The vertical deflection current Iv whose level has been appropriately adjusted by the variable resistor 9 is passed through the vertical control winding 11 of the saturable reactor 11 via the slider 10.
supplied to a.

This vertical control winding 11a includes a coil L and a capacitor C.
are connected in parallel. This parallel circuit consisting of coil L and capacitor C is tuned to the horizontal deflection frequency,
This is a resonant circuit for converting a sawtooth horizontal deflection current IH superimposed on a vertical deflection current Iv, which will be described later, into a sine wave and approximating it to a parabola.

On the other hand, the horizontal deflection output stage 12 has a sawtooth horizontal deflection current IH.
horizontal control winding 11b of saturable reactor 11.
, 11G.

FIG. 2 shows a specific configuration diagram of an example of the saturable reactor 11 in the circuit system shown in FIG. In the figure, 13 is a ferrite E-shaped core, 14 is a ferrite I-shaped core, and 15 is a permanent magnet, and a gap is provided between the central leg of the E-shaped core 13 and the I-shaped core 14. . Further, the horizontal control windings 11b and 11c wound around both outer legs of the E-shaped core 13 have the same number of turns, and are wound with polarity so as to form a closed magnetic path through the I-shaped core 14. . On the other hand, E-type core 1
A vertical control winding 11a is wound around the center leg of the motor.

Furthermore, the ■-shaped core 14 is biased by the permanent magnet 15 until just before saturation due to its magnetic saturation characteristics.

Now, assuming that the horizontal deflection current 1+ is flowing in the horizontal control windings 11b and 11c in the direction shown in FIG. A closed magnetic path is formed through .14. On the other hand, the magnetic flux φ diagram due to the permanent magnet 15 is always generated in the direction shown by the broken line.

In this state, the electron beam is deflected to the center of the screen, and a vertical deflection current of 1 V flows through the vertical control winding 11a.
When becomes zero, the magnetic flux φH is canceled in the central leg, so no current in the horizontal deflection period is induced in the vertical control winding 11a.

Next, when a vertical deflection current 1v flows through the vertical control winding 11a in the direction shown in FIG. 2, a magnetic flux φV is generated in the center leg in the direction shown by the solid line. Therefore, the magnetic flux φ and φV become (φN+φV) at (1) fill of the ■-shaped core 14, resulting in a saturated state and a large magnetic resistance. On the other hand, (II
) side, the distance between φ and φV becomes〉, and they cancel each other out, resulting in a non-saturated state and the magnetic resistance becomes small. Therefore, the magnetic flux φH' caused by the horizontal control winding 11C passes through the center leg, and a current having a horizontal deflection period is induced in the vertical control winding 11a.

Note that the vertical deflection current 1 flowing through the vertical control winding 11a
If v flows in the opposite direction to that shown in FIG. 2, the polarity of the current induced by this in the horizontal deflection period will naturally be opposite to that in the above case.

In this way, as shown in FIG. 3(A), the saturable reactor 11 and the coil and capacitor C are used.
A correction current ■ in which a parabolic wave current with a horizontal deflection period is superimposed on a vertical deflection current Iv is generated, and the coils 6a, 6
be swept away by b.

Here, the level of the vertical deflection current 1v flowing through the vertical control winding 11a is appropriately adjusted by the variable resistor 9, and the vertical and horizontal control windings 11a and 11b.

By appropriately selecting the turns ratio of 11c, for example, the above correction current 1 can be made into a correction current 1, as shown in FIG. ′ can also be generated.

Next, the coma correction operation using the above correction current will be explained. Nowadays, there is no field controller installed in the electron gun,
In addition, when a six-pole magnetic field is generated by a correction current as in this embodiment, the variable resistor 9 and the like are adjusted so that the correction current has a waveform as shown in FIG. 3(A). At this time, the amount of coma correction increases as the electron beam is deflected vertically on the vertical axis of the screen and as it is horizontally deflected. Therefore, by appropriately selecting the waveform of the correction current, it is possible to perform optimal coma correction without the green droop.

Next, as shown in FIG. 5, a field controller is provided in the electron gun to perform the optimal coma correction on the vertical axis of the screen, and as in this embodiment, the 6
When generating a polar magnetic field, the variable resistor 9 is adjusted so that the correction current has a waveform as shown in FIG. 3(B). At this time, the coma correction is zero on the vertical axis of the screen, and the coma correction 11Effi increases as the image is deflected from the vertical axis in the horizontal direction, making it possible to perform optimal coma correction.

Furthermore, it goes without saying that optimal coma correction can be achieved by creating correction waveforms other than the correction current waveforms shown in FIGS. 3A and 3B that match the correction amount of the field controller.

In this embodiment, the saturable reactor 11 is used to adjust the correction current to l! l! Of course, the correction current Iζ is not limited to this method, and the above correction current can also be obtained by using a semiconductor or the like, for example.

Effects of the Invention As described above, according to the present invention, a hexapole magnetic field is created in the neck of the picture tube by a correction current obtained by superimposing a current obtained by modulating a parabolic wave with a horizontal deflection period with a vertical deflection period on a vertical deflection current. By generating this, the residual convergence pattern due to coma aberration, which degrades the screen quality of televisions, display devices, etc., can be corrected over almost the entire screen regardless of the presence or absence of a field controller.

[Brief explanation of the drawing]

FIG. 1 is a circuit system diagram showing an embodiment of the convergence correction device according to the present invention, FIG. 2 is a specific configuration diagram showing an example of the saturable reactor in the circuit system shown in FIG. 1, and FIG. 3 (A)
, (B) are waveform diagrams of the correction current, FIG. 4, FIG. 7, and FIG. 8 are diagrams showing residual convergence patterns due to coma aberration in a conventional device, and FIGS. 5 and 6.
Each figure is a diagram explaining a conventional residual convergence pattern correction method using coma aberration. 5a, 5b... Coil, 7... Vertical deflection output stage, 3
a, 8b... Vertical deflection coil, 9... Variable resistor, 10... Slider, 11... Saturable reactor,
11a...Vertical control winding, 11b, 11c...Horizontal control @winding, 12...Horizontal deflection output stage, 13...E type core, 14...I type core, 15... Permanent magnet, C.
...Capacitor, L...Coil. Patent applicant: Victor Japan Co., Ltd. Figure 1 v Figure 2 Dan Figure 3 Figure 4

Claims (1)

[Claims] In a convergence correction device for a color picture tube equipped with an in-line electron gun, a modulated current obtained by modulating a parabolic wave with a horizontal deflection period with a vertical deflection period, or a current obtained by superimposing a vertical deflection current on the modulated current is used. A convergence correction device comprising means for generating a correction current, and means to which the correction current is supplied and generating a hexapole magnetic field in accordance with the correction current in the neck of a picture tube.