JP2551161B2 - Convergence correction device - Google Patents

Description

The present invention relates to a convergence correction device that corrects horizontal misconvergence X _H on the X axis of a screen of a color cathode ray tube.

[Conventional technology]

In recent years, the screen of a cathode ray tube (hereinafter, referred to as a television screen) in a color television receiver or a color display device has been tending to have a higher definition and a larger size. In addition, the magnetic field distribution of the horizontal deflection coil tends to be more linear. However, if the magnetic field distribution of the horizontal deflection coil is made linear, the color misregistration between blue B and red R on the X axis, that is, the horizontal under-miss convergence X _H as shown in FIG. 6B appears. Therefore, it is desired to make this correction. In addition, when designing the color deflection yoke, the convergence trilemma is misconverged X _H
It may aggregate, this case also it is necessary to correct the aggregated misconvergence X _H.

In order to perform the correction of the misconvergence X _H is,
An electron gun G _B of blue B, and the electron gun G _G of the green G, and an electron gun G _R of the red R, in the cathode ray tube from the left as viewed from the screen side are in-line array to the right, blue B
The four-pole correction coil, which is connected so that the correction magnetic field that crosses the red beam and the red R beam is generated upside down, is arranged at the neck of the color deflection yoke, and this correction coil is synchronized with the horizontal deflection pulse. It is known that a parabola current may be applied.

As a circuit for generating this parabolic current, the circuits shown in FIGS. 7 and 8 can be considered. In the circuit shown in FIG. 7, the first correction coil 2 and the second correction coil 3 are connected to the inductance connected in series with the horizontal deflection coil 1, and the parabolic current is generated by utilizing the resonance of the resonance circuit. Then, this is added to the correction coils 2 and 3 as a correction current.

Further, in the circuit shown in FIG. 8, four saturable coils 4 are connected to a bridge and the parabolic current generated by this bridge circuit is applied to the correction coils 2 and 3.

[Problems to be Solved by the Invention]

However, since the circuit shown in FIG. 7 generates a correction current by resonance, the waveform of the generated current has a waveform portion between peaks of a sine waveform as shown by the solid line in FIG. Will be taken out. For this reason, the peak portions 5 at both ends of the waveform are blunted, a current having a sharp rise at both ends as shown by a chain line cannot be obtained, and there is a problem that the correct misconvergence X _H cannot be corrected.

Further, in the circuit shown in FIG. 8, the correction current is generated by the bridge circuit. This method has a problem that the sensitivity of correction is generally poor. of course,
The sensitivity can be increased by increasing the number of turns of the correction coils 2 and 3. However, if this is done, the inductance of the correction coils 2 and 3 becomes unnecessarily large, and the deflection current flowing in the horizontal deflection coil 1 is reduced to reduce the deflection amplitude. A new problem arises that

This invention has been made in view of the above circumstances, and its object is almost ideal parabolic waveform misconvergence X _H precision based on capable convergence correction device that corrects its on X-axis by the current To provide.

[Means for solving the problem]

The present invention is configured as follows to achieve the above object. That is, according to the present invention, a four-pole correction coil for correcting horizontal misconvergence on the X-axis of the screen of the cathode ray tube is arranged in the net portion of the color deflection yoke, and the horizontal deflection current is applied to the correction coil. What is claimed is: 1. A convergence correction device, comprising: a full-wave rectification circuit for full-wave rectifying and supplying a correction current of a parabolic waveform synchronized with a horizontal deflection cycle, wherein the full-wave rectification circuit comprises a positive pulse rise of a horizontal deflection voltage. ON operation at the position, having a peak value on the positive side at the start position of the scanning period and producing a correction current on one side of the parabolic waveform that becomes zero at the middle position of the scanning period, and the sawtooth wave of the horizontal deflection current. A transistor element that is turned on at the positive inrush position and creates a correction current on the other side of the parabolic waveform having a peak value on the positive side at the end position of the scanning period, and the diode. Ri is configured as characterized by being configured to have an inductance element to balance the peak value of the correction current produced by the transistor element and the peak value of the correction current issued.

[Action]

In the present invention, when a horizontal deflection voltage is applied to the diode, the diode turns on at the position where the horizontal deflection voltage becomes positive, that is, at the start position of the blanking period and turns off at the end position of the blanking period. When this is turned off, a current that tries to prevent a decrease in the current flows in the correction coil.Therefore, this diode has a peak value on the positive side at the end position of the blanking period, that is, the start position of the scanning period, A correction current for the left half of the parabolic waveform that is 0 at the center position is created. On the other hand, a horizontal deflection current is supplied to the transistor element, which is turned on at a position where the sawtooth wave of the horizontal deflection current rushes to the positive side, that is, at an intermediate position of the scanning period, and at the end position of the scanning period, the positive side is turned on. A correction current of the right half waveform of the parabolic waveform having a peak value at is generated. The inductance element balances the inductance of the path in which the horizontal deflection current flows to the diode side and the inductance of the path to the transistor side, and adjusts the peak value created by the diode and the peak value created by the transistor element to the same, Creates an ideal parabolic waveform correction current with a balanced left and right. This correction current is applied to the correction coil to correct the misconvergence X _H.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration of an embodiment of the convergence correction device according to the present invention, and FIG. 2 shows the arrangement of the correction coil with respect to the color deflection yoke. The convergence correction device of this embodiment includes a full-wave rectifier circuit 18 and correction coils 14a and 14b.
Reference numeral 8 includes resistors 6 and 7, a differential coil 8 as an inductance element, diodes 10 and 11, and a transistor 12 as a transistor element. The diodes 10, 11
Are connected to each other on the anode side, and the cathode side of the diode 10 is connected to one end side of the differential coil 8. The other end of the differential coil 8 is connected to the base of the transistor 12 via a resistor 7 that protects the transistor 12. The collector side of the transistor 12 is connected to the cathode side of the diode 11, and the emitter side is connected to the resistor 6
Is connected to the other end side of the differential coil 8, that is, to the resonance connection portion between the resistor 7 and the differential coil 8. The connection between the emitter side of the transistor 12 and the resistor 6 is connected to the cold side of the horizontal deflection coil 13 that constitutes the color deflection yoke. The correction coils 14a and 14b are connected in series, one end side of which is connected to the anode side of the diodes 10 and 11 and the other end side of which is connected to the extraction tap 15 of the differential coil 8.

As shown in FIG. 2, the correction coils 14a and 14b are windings wound around U-shaped cores 16a and 16b. In this embodiment, the correction coils 14a and 14b are color deflection yokes. Are arranged opposite to each other on the left and right sides of the neck portion 17.
Then, the correction coils 14a, when the parabolic current is applied to 14b, toward the bottom side correction magnetic field B _S in the beam side of blue B is from the top side, the correction magnetic field B _S in the beam side of the red R is from the bottom side The wiring directions of the correction coils 14a and 14b are determined so as to be directed to the top side. The color deflection yoke has a horizontal deflection coil 13 and a vertical deflection coil (not shown) mounted on an annular core (not shown) via a bobbin (not shown). Since the structure of the color deflection yoke is known, its description is omitted.

This embodiment is configured as described above, and its operation will be described below.

When driving the color deflection yoke, the horizontal deflection current of the sawtooth wave is supplied from the horizontal deflection coil 13 to the full-wave rectifier circuit 18. At this time, the horizontal deflection voltage shown in FIG. Has been done. Therefore, the diode 10 in the forward direction turns on at the position where this horizontal deflection voltage is positive, that is, at the start position t ₁ of the blanking period, and passes the current of the _peak value i _H1 at the end position t ₂ of the blanking period. Let This diode 10 is turned off at the end point t ₂ of the blanking period, but at this time, the current that tries to maintain the current in the correction coils 14a and 14b, that is, the current that tries to prevent the reduction of the current is the scanning period. flow over the intermediate position t _3, as shown in FIG. 3 (a), the correction current i ₁ in the left half of the waveform of the parabolic waveform is produced.

On the other hand, the base side of the transistor 12 is shown in FIG.
A sawtooth horizontal deflection current as shown in
When this horizontal deflection current rushes from the negative side to the positive side, the transistor 12 is turned on, and the collector current shown by the chain line in the figure flows. This collector current is 0 at the intermediate position t ₃ of the scanning period.
Then, the correction current i ₂ of the right half of the parabolic waveform having the peak value i _H2 at the end point t ₄ of the scanning period is generated.

In this way, the diode 10 and the transistor 12 produce a correction current having a parabolic waveform as shown in FIG. 3 (c). In the state shown in FIG. 3 (c), the peak value i _H1 is larger than i _H2 and is unbalanced. Such an imbalance between the _peak values i _H1 and i _H2 is corrected by adjusting the inductance of the differential coil 8. That is, by moving the core of the differential coil 8 back and forth, the inductance L ₁ between the extraction tap 15 and the base side of the transistor 12, the extraction tap 15 and the diode 10
It is possible to variably adjust the magnitude of the inductance L ₂ on the cathode side of the. With this variable adjustment, the inductance
If L ₁ is decreased and L ₂ is increased, the current flowing to the diode 10 side increases and the peak value i _H1 increases. On the other hand, if the inductance L ₁ is increased and L ₂ is decreased,
The current flowing through the transistor 12 increases and the peak value i _H2 increases. In this way, the peak values i _H1 and i _H2 can be adjusted by variably adjusting the ratio of L ₁ and L ₂ of the differential coil 8, and as a result, as shown in FIG. 3 (d). In addition, a correction current having an ideal parabolic waveform that is symmetrical and balanced and has the same crest values i _H1 and i _H2 is created. The parabolic current of this ideal waveform is corrected by the correction coils 14a, 14a.
Added to b.

When a correction current is applied to the correction coils 14a and 14b, the second
As shown in the figure, an N pole is formed on one side of the cores 16a and 16b, and an S pole is formed on the other side, so that a correction magnetic field B _{S of} four poles is generated. This correction magnetic field crosses the blue B beam from the top side to the bottom side, and exerts a force on the blue B beam in the left direction as viewed from the screen side to move in that direction. On the other hand, the red R beam is traversed by the correction magnetic field B _S traveling from the bottom side to the top side, and exerts a rightward force on the red R beam as viewed from the screen side to move it in the direction of the force. That is, on the television screen, the blue B moves to the left and the red R moves to the right, and as shown in FIG. 6 (a), the misconvergence X _{H is in} the overdirection (in the same direction as the electron gun color arrangement direction). Blue B and red R are misaligned with each other in the direction of misconvergence X _H ), and the reverse pattern of the undertype misconvergence X _H as shown in FIG. 6 (b) is effectively corrected. Of.

Further, in the present embodiment, if the connections of the correction coils 14a, 14b are made to have opposite polarities, the directions of the currents flowing through the correction coils 14a, 14b become opposite, so the direction of the correction magnetic field B _S becomes opposite, and therefore, The moving directions of the blue B beam and the red R beam are also opposite, and the over-type misconvergence X _H as shown in FIG. 6A is effectively corrected.

The present invention is not limited to the above embodiment,
Various embodiments can be adopted. For example, in the above embodiment, as shown in FIG. 2, the correction coils 14a, 14b
Are arranged at the left and right positions of the neck portion 17 of the color deflection yoke. For example, as shown in FIG.
It may be arranged so as to face each other in the vertical direction and the correction magnetic field B _S of four poles is similarly generated to correct the misconvergence X _H.

In the above embodiment, the full-wave rectifier circuit 18 has a diode.
Although 11 is provided, this diode 11 can be omitted. Further, the diode 10 can be designed in a circuit with its direction reversed.

Further, in the above embodiment, the inductance element is constituted by the differential coil 8. However, as shown in FIG. 5, for example, the terminal side of the correction coil 14a, the cathode side of the diode 10 and the base side of the transistor 12 are provided. It is also possible to provide coils 20 and 21 as inductance elements and adjust the inductances L ₁ and L ₂ of the coils 20 and 21 to balance the _peak values i _H1 and i _H2 .

Furthermore, although the transistor element is constituted by the transistor 12 in the above embodiment, it may be constituted by a FET (field effect transistor).

Further, although the correction coils 14a and 14b are connected in series in the above embodiment, they may be connected in parallel, and in the present embodiment, the horizontal deflection coil 13 is connected in parallel. You may connect.

〔The invention's effect〕

The present invention is configured such that a diode produces a correction current on one side of a parabolic waveform and a transistor element produces a waveform on the other side of a parabolic waveform to form a correction current of the parabolic waveform, and the correction of the parabolic waveform is performed. Since the size of the peak value at the start position and the peak value at the end point of the current scanning period is adjusted by an inductance element, it is necessary to create a parabola correction current of an ideal waveform with a balanced left and right. Is possible, which allows misconvergence X _H
Can be corrected with high accuracy.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of a convergence correction device according to the present invention, FIG. 2 is a diagram showing an arrangement of correction coils in the embodiment, and FIG. 3 is an example of forming a correction current in the device of the embodiment. Explanatory diagram, FIG. 4 is an explanatory diagram showing another arrangement example of the correction coil, FIG. 5 is a circuit diagram of another embodiment of the convergence correction device according to the present invention, and FIG. 6 is a pattern example of misconvergence X _H. FIG. 6 (a) is a pattern diagram of over-type misconvergence X _H , FIG. 6 (b) is a pattern diagram of under-type misconvergence X _H , and FIGS. 7 and 8 are misconvergence.
A circuit diagram generally considered as a circuit for generating a correction current of X _H , and FIG. 9 is a waveform diagram showing the correction current generated by the circuit of FIG. 7 in comparison with an ideal waveform parabolic current. 1 ... Horizontal deflection coil, 2 ... First correction coil, 3 ...
… Second correction coil, 4 …… saturable coil, 5 …… peak part, 6,7 …… resistor, 8 …… differential coil, 10,11 ……
Diode, 12 ... Transistor, 13 ... Horizontal deflection coil, 14a, 14b ... Correction coil, 15 ... Extraction tap, 1
6a, 16b …… Core, 17 …… Neck part, 18 …… Full wave rectifier circuit, 20,21 …… Coil.

Claims (1)

(57) [Claims] 1. A 4-pole correction coil for correcting horizontal misconvergence on the X-axis of the screen of a cathode ray tube is arranged at the neck portion of a color deflection yoke, and the horizontal deflection current is supplied to this correction coil. A convergence correction device provided with a full-wave rectification circuit that rectifies waves and supplies a correction current of a parabolic waveform synchronized with a horizontal deflection period, wherein the full-wave rectification circuit comprises a positive pulse rising position of a horizontal deflection voltage. ON, the diode has a peak value on the positive side at the start position of the scanning period and produces a correction current on one side of the parabolic waveform that becomes zero at the middle position of the scanning period, and the positive sawtooth wave of the horizontal deflection current. The transistor element that is turned on at the inrush position and that generates the correction current on the other side of the parabolic waveform that has the peak value on the positive side at the end position of the scanning period and the diode. Convergence correction apparatus characterized by being configured to have an inductance element to balance the peak value of the correction current produced by the peak value and the transistor of that correction current.