JPH03182172A - Raster distortion correction circuit - Google Patents

Abstract

PURPOSE:To correct left right raster distortion such as inner barrel and inner pin in an excellent way by winding a vertical winding onto a saturable reactor for horizontal S-shape correction and varying the S-shape correction quantity dynamically with a vertical control current. CONSTITUTION:A saturable reactor 5 with a horizontal winding 5H and a vertical winding 5V wound thereto is inserted in series with a horizontal deflection coil 4 in a horizontal deflection output circuit. The horizontal S-shape correction quantity is changed dynamically at the vertical period by supplying a correction current of the vertical period to the vertical winding 5V of the saturable reactor 5 to correct the inner barrel and inner pin distortion. Thus, a left right pin cushion distortion correction circuit is obtained, by correcting left right raster distortion in an excellent way on the entire pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a raster distortion correction circuit in the left and right direction used in color television receivers and the like.

[Conventional technology]

The left-right pincushion distortion of a television receiver is determined by the magnetic field distribution characteristics of the deflection yoke, the deflection angle of the picture tube, and the curvature of the face plate of the picture tube, and usually exhibits pincushion distortion characteristics.

This is corrected by a well-known left and right pincushion distortion correction circuit, and the pincushion distortion is corrected by parabolically modulating the amplitude of the horizontal deflection current with a vertical period. Various left and right pincushion distortion correction circuits have been proposed, including (11 saturable reactor system, (2) power supply modulation system, and (3+ diode modulator system), but recent wide-angle deflection large color picture tubes, etc. ) diode modulator method is widely used.

In recent years, there has been a strong trend toward flattening the face plates of color picture tubes, but in view of the doming characteristics of color picture tubes, the flattening tends to take the form of an aspherical structure.

The left-right pincushion distortion of a color picture tube using such an aspherical structure panel is shown in Figure 2 (al), and in the horizontal direction, from the center of the screen to the middle part on the horizontal (or the pincushion distortion is large as shown by the broken line), and the pincushion distortion (hereinafter referred to as pin strain) increases rapidly near the x ring end as shown by the solid line (or the pin distortion is small as shown by the broken line). It's located around 1.

If this is corrected using the conventional left and right pincushion distortion correction circuit described above, in the solid line example of ta+ in Fig. 2, if the pin distortion at the X-axis end is corrected, the intermediate part will be In this case, left-right distortion due to the so-called inner barrel tendency is left behind due to over-correction.

In addition, in the example of pin distortion before correction shown by the broken line in Fig. 2 (al),
When correcting with the conventional left and right pincushion distortion correction circuit, the distortion shown in Fig. 2 (C
As shown in No. 1, there is a drawback that left-right distortion with a so-called inner pin tendency, which is under-corrected in the middle portion, remains.

[Problem to be solved by the invention]

In this way, raster nonlinear left-right pincushion distortion, which is determined by the magnetic field distribution characteristics of the face plate and deflection yoke of a picture tube that aims to flatten it, can be solved using the existing saturable reactor method, power modulation method, or diode modulator method. Even if left and right pincushion distortion correction circuits such as the above are used, satisfactory correction cannot be achieved, and the reality is that a compromise correction is performed that balances the distortion in the middle on the X-axis and the distortion at the ends of the X-axis.

This invention was made to solve the above-mentioned problem. It is an object of the present invention to provide a left-right pincushion distortion correction circuit that can satisfactorily correct left-right pincushion distortion or raster distortion over the entire screen.

[Means to solve the problem]

The raster distortion correction circuit according to the present invention includes a horizontal winding and a vertical split gJ in series with the horizontal deflection coil in the horizontal deflection output circuit.
A saturable reactor with a winding is inserted.

[For production]

In this invention, the inner barrel and inner pin distortions are corrected by dynamically changing the horizontal three-figure correction amount in the vertical period by flowing a correction current with a vertical period through the vertical winding of the saturable reactor.

〔Example〕

Embodiments of the raster distortion correction circuit of the present invention will be described below with reference to the drawings. FIG. 1+8) is a circuit diagram showing the configuration of one embodiment.

The embodiment shown in FIG. 1+a) exemplifies a case where a known diode modulator type left and right pincushion distortion correction circuit is included in the horizontal deflection output circuit.

In this Figure 1 (al), 1 is a horizontal output transistor, the base of which is grounded via the secondary winding 2 of the transformer.The primary @ line of the transformer is not shown, but the An oscillation signal is applied, and this 1
The horizontal oscillation signal applied to the secondary winding is induced in the secondary winding 2 and supplied to the base of the horizontal output transistor 1.

The emitter of the horizontal output transistor 1 is grounded, and the collector is connected to a 10B power supply via a flybank transformer 3. The connection point between this flyback transformer 3 and the collector of the horizontal output transistor 1 is the horizontal Jlv between the horizontal deflection coil 4 and the terminals a and b of the saturable reactor 5.
It is grounded via A5H, capacitor 6, coil 7 and capacitor 8. The saturable reactor 5 has terminal c,
It also has a vertical winding 5■ connected to d.

Further, a capacitor 9. is connected between the collector and emitter of the horizontal output transistor l. A series circuit of IO and a series circuit of diodes 11 and 12 are connected.

Connection point between capacitors 9 and 10 and diodes 11 and 12
A capacitor 13 is connected between the connection points with
Also, the connection point between diodes 11 and 12 and the capacitor 6
The connection points between the coil 7 and the coil 7 are directly connected.

The connection point between the coil 7 and the capacitor 8 is connected to the collector of the vertical modulation output transistor 14 of the diode modulator circuit.

This vertical modulation output transistor 14, capacitors 8 to 1
3, coil 7, etc., form a diode modulator circuit, but detailed explanation thereof will be omitted here. Further, it is assumed that the left-right pincushion distortion in the absence of the saturable reactor 5 is corrected by the diode modulator described above up to FIG. 2(b).

Furthermore, the saturable reactor 5 is a single coil as shown in FIG. It is a reactor.

That is, 5a and 5b are saturable cores and are made of ferrite or the like. These saturable cores 5a, 5b
A magnet 15 with a magnetic pole N-3 is inserted between them to apply a magnetic bias to the saturable cores 5a and 5b.

The saturable cores 5a and 5b have the horizontal t! The wire 5H and the vertical winding 5v are wound, and the terminal c of the vertical winding 5v
, d with a vertical period.

Next, the operation will be explained. A magnetic bias is applied to the saturable coils 5a and 5b of the saturable reactor 5 by a magnet 15, and the inductance characteristics between terminals a and b of the horizontal winding 5H, that is, the saturable coils 5a and 5b for this three-character correction The superposition characteristic of the reactor 5 is, for example, shown in FIG.
become that way.

In other words, if the horizontal deflection current increases (both +/-)
, the inductance between terminals a and b increases, and the deflection current is suppressed in the large current region, that is, the amount of deflection at the left and right edges of the screen due to the increase in inductance, showing a shrinkage (figure 8 correction) effect at both ends. The bias is a constant amount due to the magnet 15.

In addition, if the terminals c and d of the vertical winding & 1I5V are wound as shown in Fig. 1 (bl) and the polarity current is applied to the terminal d (g) and the terminal C (g), the magnetic bias of the magnet 15 will be further increased. It becomes larger, and the characteristics become as shown in Fig. 1.

Conversely, if the current is applied, the magnetic bias of the magnet 15 will be canceled out, resulting in characteristic C.

In the state of characteristic A, almost no S-shape correction is performed, and in the state of characteristic C, an 8-shape correction that is greater than the S-shape correction of characteristic a is performed.

Here, we pay attention to the state of Fig. 2 (bl).
As is clear from bl, since the upper and lower ends of the screen (beginning and end of vertical period scanning) are elongated at both ends, the figure 8 correction amount of the horizontal deflection current is increased, and conversely, at the middle part of the screen during vertical scanning, That is, in the vicinity of the X-axis, by reducing the figure-8 correction amount, the inner barrel state will be corrected.

In other words, the vertical winding of Fig. 1 (mountain) & 115V terminal C1d
By dynamically changing the vertical cycle control current in between (in this case, the upper and lower parts of the screen are set to a state of characteristic a, and the center of the screen is set to a state of characteristic A), raster distortion can be ideally It is corrected to

Of course, after the dynamic correction in the vertical direction by the saturable reactor 5, it may be necessary to slightly increase or decrease the correction amount of the left and right pincushion distortion correction circuits from the original state, but this does not pose any problem.

In the above embodiment, an example of correction for the inner barrel state has been explained, but it is possible to similarly correct the inner pin state in FIG. 2 (C1) by changing the polarity of the vertical I!!5V. .

Further, in the above embodiment, explanation was given on the premise that the correction is combined with the correction by the left and right pincushion distortion correction circuit, but the present invention also applies to inner pin and inner barrel distortion in a pin-free deflection system that does not require a left and right pincushion distortion correction circuit. This can be corrected using the method.

Furthermore, in the above embodiment, although the explanation is omitted, the asymmetrical horizontal linearity between the left and right sides of the screen may require the insertion of a normal horizontal linearity coil in series with the horizontal deflection coil.

In addition, the 1st V! Since the saturable reactor 5 of this invention of J(bl) is provided with a vertical 5g5V, the magnet 15 is not necessarily required, and it is possible to use it with or without the magnet 15.

〔Effect of the invention〕

As described above, according to the present invention, the vertical winding is wound around the saturable reactor for horizontal figure-8 correction, and the figure-8 correction amount is dynamically changed by the vertical control current. It is now possible to correct left and right raster distortions such as the following, and it is possible to form a good raster with very good linearity.

[Brief explanation of drawings]

1I(a+ is a circuit diagram of a Rusk distortion correction circuit according to an embodiment of the present invention, LV!J(b) is an explanatory diagram of the configuration of a saturable reactor in the same embodiment, and FIG.
Superposition characteristic diagram of the saturable reactor of bl, Fig. 2 ia+ to Fig. 2 (C1 is an explanatory diagram showing each state before conventional Rask distortion correction. l...Horizontal output transistor, 3... Fly Bank transformer, 4...Horizontal deflection coil, 5...Saturable reactor, 5H...Horizontal winding, 5V...Vertical winding, 6
．． 8-10.13... Capacitor, 11.12...
Diode, 14... Vertical output transistor, 15.
··magnet. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A horizontal deflection output circuit that supplies a deflection current to a horizontal deflection coil, and a horizontal winding for horizontal S-shaped correction inserted in series with the horizontal deflection coil, and a vertical period correction current is passed through the vertical winding. A raster distortion correction circuit comprising a saturable reactor that dynamically changes a horizontal S-curve correction amount in a vertical cycle.