JP2770698B2 - Deflection yoke - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-convergence type deflection yoke mounted on an in-line type color picture tube. In particular, it is an object of the present invention to provide a deflection yoke that can easily correct a reverse pattern of cross miss convergence.

[0002]

2. Description of the Related Art In an image display apparatus using a three-electron gun in-line type color picture tube, a method for well converging three electron beams emitted from a three-electron gun on a screen surface (on a screen). As one of the methods, there is a method using a deflection yoke of a self-convergence method. The deflection yoke of the self-convergence method
The saddle-type horizontal deflection coil and the saddle-type vertical deflection coil make the horizontal deflection magnetic field a strong pincushion type and the vertical deflection magnetic field a strong barrel type to obtain good convergence.

However, when the vertical deflection angle on the color picture tube is reduced to about 90 °, the above-mentioned magnetic field distribution for obtaining good convergence indicates that the upper and lower rasters of the screen have pincushion distortion and barrel distortion. Distortion occurs and cannot be put to practical use. Further, when trying to correct the distortion of the upper and lower rasters, the cross-misconvergence shown in FIGS. 5 and 6 occurs, which is not practical. Thus, it has been very difficult to simultaneously satisfy the distortion and convergence of the upper and lower rasters.

Therefore, conventionally, there has been proposed a method of using a saturable reactor or the like in a deflection circuit in order to correct cross-miss convergence and simultaneously satisfy distortion and convergence of upper and lower rasters. However, even if the cross miss convergence is corrected to almost zero by using this method, as shown in FIG.
A so-called cross miss convergence reversal pattern in which a positive cross occurs at the screen intermediate portion b occurs. Therefore, it is not satisfactory as a display device requiring high accuracy.

In a flat face picture tube having a small screen curvature, the above-mentioned inverted pattern is more emphasized, which may cause a problem in general use other than high precision use.

Further, conventionally, in order to correct the reverse pattern of the cross miss convergence, it is necessary to manually add a magnetic piece or the like for each deflection yoke and adjust it for each deflection yoke. It was bad.

From the inversion pattern shown in FIG. 7, the conventional method has the following advantages: the optimum magnetic field distribution (ideal magnetic field distribution that simultaneously satisfies the distortion and convergence of the upper and lower rasters)
It can be seen that the vertical deflection magnetic field deviates in the direction of the pincushion magnetic field at the screen middle part b and in the barrel-type magnetic field direction at the screen peripheral part a.

[0008]

The problem to be solved by the present invention is that it is possible to easily correct the reverse pattern of the cross miss convergence, to achieve both the elimination of the distortion of the raster at the top and bottom of the screen and the convergence, and the convergence quality. What means should be taken to make the deflection yoke capable of greatly improving the deflection yoke?

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a self-convergence type deflection system comprising at least a pair of saddle type horizontal deflection coils and at least a pair of saddle type vertical deflection coils. In York,

A tap is provided in the middle of each of the at least one pair of saddle type vertical deflection coils, and a plurality of taps are connected in parallel with opposite polarities between the tap and the beginning of the winding provided with the tap. And a diode block composed of the above-mentioned diode is connected in parallel with the winding.

[0011]

FIG. 1 shows a main part of a first embodiment. In this embodiment, the saddle-type horizontal deflection coil is the same as a conventional general deflection coil, so that illustration and description of the coil are omitted here.

Taps T1 and T2 are provided between the windings of a pair of saddle type vertical deflection coils L1 and L2 connected in series.
Is provided. Diodes D1, D connected in parallel with opposite polarities between the tap T1 and the winding start S of the coil L1
2 is connected in parallel with the coil L1. Further, diodes D3 and D3 connected in parallel with opposite polarities between the tap T2 and the winding start S of the coil L2.
A diode block composed of D4 is connected in parallel with the coil L2.

As the diodes D1 to D4, those having a characteristic that the vertical deflection angle is such that the diodes are turned on at the position of the substantially middle portion b of the screen shown in FIG. 7 are selected.

L3 and L4 are frame correction coils as in the prior art, R1 and R3 are fixed resistors, and R2 is a variable resistor.

Next, the operation of the deflection yoke will be described. First, in the section from the position where the vertical deflection angle is 0 ° (that is, on the screen x-axis in FIGS. 5 to 7) until the diodes D1 to D4 are turned on (the section from the screen to approximately the middle part b), the saddle type The same current (vertical deflection current) flows between the winding start S of each of the vertical deflection coils L1 and L2 and the taps T1 and T2, and between the winding end F and the taps T1 and T2. At this time, the coils are adjusted in advance so as to form a magnetic field distribution that optimizes (minimizes) the cross-misconvergence in the substantially middle portion b of the screen. Next, in a section in which the vertical deflection angle further increases and the diodes D1 to D4 are turned on and the vertical deflection angle reaches the screen peripheral portion a, an increase in the vertical deflection current between the winding start S and the tap is suppressed (the current is reduced). This is suppressed because the current is diverted to the diode block side), and the magnetomotive force at that portion is also suppressed. Therefore, the magnetic field distribution formed after the diodes D1 to D4 are turned on changes in the pincushion magnetic field distribution direction more than the magnetic field distribution formed before the diodes were turned on. Therefore, the magnetic field distribution which tends to shift in the barrel-shaped magnetic field distribution direction in the peripheral portion a of the screen in the conventional apparatus can be corrected in the present embodiment, and the occurrence of the inversion pattern can be suppressed.

The position at which the diode is turned on is adjusted within the range of the substantially middle portion b of the screen so that the occurrence of the inversion pattern is minimized.

Next, a second embodiment is shown in FIG. In this embodiment, each diode block of the first embodiment has a new 4
The pole correction coils L5 and L6 are connected in series. The frame correction coils L5 and L6 are located at positions where the frame correction coils L3 and L4 are provided as in the related art (that is, positions behind the horizontal and vertical deflection coils (from the electron gun)).
To be provided.

By turning on and off the diodes D1 to D4 described in the first embodiment, currents having a waveform as shown in FIG. 3 (shunted from the vertical deflection current flowing through the vertical deflection coil) are supplied to the frame correction coils L5 and L6. Current). If the generated magnetic fields are formed so that the generated magnetic field has the same polarity as the vertical deflection magnetic field, after the diodes D1 to D4 are turned on, the center of the vertical deflection magnetic field of the deflection yoke is on the electron gun side. (The frame correction coils L5 and L6
Are located behind the horizontal and vertical deflection coils L1 and L2 (from the electron gun). At this time, the horizontal deflection magnetic field distribution does not change, and the vertical deflection magnetic field distribution moves relatively, so that the cross miss convergence changes in the positive cross direction.

Therefore, in the second embodiment, in addition to the change in the vertical magnetic field distribution described in the first embodiment (a change in which the pincushion magnetic field distribution is strengthened at the peripheral portion of the screen), the movement of the center of the vertical deflection magnetic field causes inversion. The effect of correcting the pattern is further enhanced.

Further, the second embodiment has the effect of reducing the phase delay of the current flowing through the vertical deflection coil even for a sudden change in the vertical deflection current immediately after the vertical flyback period. As described above, the present invention is particularly effective for an apparatus in which the period from the vertical blanking period to the display period is short. Further, in the second embodiment, since the current flows through the frame correction coils L5 and L6 from the position where the vertical deflection angle is in the middle of the screen, the tracking of the frame error occurring in the vertical direction can be corrected.

A resistor (either a fixed resistor or a variable resistor) may be provided instead of the frame correction coils L5 and L6 to adjust the amount of current shunted to the diode block side and adjust the effect of correcting the inversion pattern. Is also good.

Next, a third embodiment is shown in FIG. In this embodiment, a resistor R4 and a resistor R6 are connected in series to each diode block, a resistor R5 is connected between the winding start S of the coil L1 and the tap T1, and a resistor R7 is connected to the winding start S of the coil L2. And a tap T2. (Others are the same as in the second embodiment.)

In the third embodiment, the amount of current shunted to each diode block can be adjusted by the resistors R4 to R7 (particularly, the resistors R4 and R6), and the inversion pattern can be corrected more finely. Note that each of the resistors R4 to R7 may be a variable resistor.

Next, a fourth embodiment is shown in FIG. In this embodiment, the winding start S of each of the vertical deflection coils L1 and L2 is connected to each other so that the winding start has the same potential, and diodes D1 and D connected in parallel with opposite polarities between the taps T1 and T2.
2 are connected in parallel with the coils L1 and L2. Then, four-pole frame correction coils L5 and L6 are connected in series to the diode block. The resistor R11 and the coil L7 are elements for adjustment.
Note that, similarly to the second embodiment, the frame correction coils L5 and L6 are located at positions where the frame correction coils L3 and L4 are provided as in the related art (that is, behind the horizontal and vertical deflection coils (from the electron gun)). Position). Also, based on the start, tap, and end of winding of the vertical deflection coils L1 and L2,
For convenience, the winding blocks are divided into four blocks A to D.

The operation of the deflection yoke according to the fourth embodiment will be described. The operation of this embodiment is almost the same as the operation of the second embodiment. First, the position where the vertical deflection angle is 0 ° (that is, FIGS.
In the section (on the screen x-axis in FIG. 7) until the diodes D1 and D2 are turned on (the section up to the substantially middle part b of the screen), the winding start S and the tap T1 of each of the saddle type vertical deflection coils L1 and L2. The same current (vertical deflection current) flows between T2 and between the winding end F and the taps T1 and T2. At this time, the coils are adjusted in advance so as to form a magnetic field distribution that optimizes (minimizes) the cross-misconvergence in the substantially middle portion b of the screen. Next, in a section where the vertical deflection angle further increases and the diodes D1 and D2 are turned on and the vertical deflection angle reaches the peripheral portion a of the screen, an increase in the vertical deflection current between the winding start S and the tap is suppressed (the current is reduced). This is suppressed because the current is diverted to the diode block side), and the magnetomotive force at that portion is also suppressed. Therefore, the magnetic field distribution formed after the diodes D1 and D2 are turned on changes in the direction of the pincushion magnetic field distribution more than the magnetic field distribution formed before the diodes were turned on. Therefore, the magnetic field distribution that tends to shift in the barrel-shaped magnetic field distribution direction at the screen peripheral portion a in the conventional device is
In this embodiment, the correction can be performed, and the occurrence of the inversion pattern can be suppressed.

FIGS. 9A and 9B schematically show the magnetic field distribution before the diode is turned on and after the diode is turned on.
(This figure is a cross-sectional view of a pair of vertical deflection coils L1 and L2). It can also be seen from the figure that the magnetic field distribution that tends to shift in the barrel-shaped magnetic field distribution direction at the periphery of the screen can be corrected by turning on the diode.

The position where the diode is turned on is adjusted within the range of the substantially middle portion b of the screen so that the occurrence of the reverse pattern is minimized.

Here, the frame correction coils L5 and L6 include:
By turning on and off the diodes D1 and D2, a current having a waveform as shown in FIG. 3 (a current shunted from the vertical deflection current flowing through the vertical deflection coil) flows. If the generated magnetic fields are formed so that the generated magnetic field has the same polarity as the vertical deflection magnetic field, after the diodes D1 and D2 are turned on, the center of the vertical deflection magnetic field of the deflection yoke is on the electron gun side. (Because the frame correction coils L5 and L6 are located behind (from the electron gun) the horizontal and vertical deflection coils L1 and L2). At this time, the horizontal deflection magnetic field distribution does not change, and the vertical deflection magnetic field distribution moves relatively, so that the cross miss convergence changes in the positive cross direction.

Therefore, the fourth embodiment is similar to the second embodiment. (1) In addition to the change in the vertical magnetic field distribution described in the first embodiment (the change in which the pincushion-type magnetic field distribution is enhanced around the screen). By moving the center of the vertical deflection magnetic field, the effect of correcting the inverted pattern is further enhanced.

(2) The effect of reducing the phase lag of the current flowing through the vertical deflection coil even for a sudden change in the vertical deflection current immediately after the vertical retrace period is obtained. This is particularly effective for a device in which the period from the period to the display period is short.

(3) Since a current flows through the frame correction coils L5 and L6 from the position where the vertical deflection angle is in the middle of the screen, the tracking of the frame error occurring in the vertical direction can also be corrected.

Next, a fifth embodiment is shown in FIG. In this embodiment, as shown in FIG. 11, taps T1 and T2 (see FIG. 11A) are divided into winding start taps T1S and T2S and winding end taps T1F and T2F, respectively (see FIG. )reference). That is, a pair of saddle type vertical deflection coils L1, L2
The winding start side of the cut end is referred to as a winding start side tap T1S, T2S, and the winding end side of the cut end is referred to as a winding end side tap T1F, T2F. The winding start tap T1S of the vertical deflection coil L1 and the vertical deflection coil L2
And the winding start tap T2S of the vertical deflection coil L2 and the winding end tap T1F of the vertical deflection coil L1 are connected to have the same potential. The winding end F and the winding end F of the vertical deflection coil L2 are connected to have the same potential. Further, a diode block similar to the fourth embodiment and the frame correction coils L5 and L6 are connected between the winding start points S of the pair of vertical deflection coils L1 and L2.

When the winding blocks A to D are considered based on the direction of current flow and corresponding to the fourth embodiment, the order is as shown in FIG. (For example, in the fourth embodiment, the winding block A is a section in which current flows in the tap direction from the winding start S, and the corresponding section in the fifth embodiment is the coil L1.
From the winding start S to the winding start side tap T1S. )

As described above, the fifth embodiment is realized by changing the connection state of the winding blocks A to D of the fourth embodiment, and the operation and effects are the same as those of the fourth embodiment.

In both the fourth and fifth embodiments, a resistor may be connected in series to the diode block as in the third embodiment. At this time, the frame correction coils L5 and L6 can be omitted.

Here, when the deflection yoke body generates a large amount of heat (during high-frequency operation) or when the deflection yoke is used in an environment with a high ambient temperature, such as inside a display device,
The DC resistance of the coils L1 and L2 may significantly increase due to heat (in that case, the DC resistance between the winding start and the tap, which are part of the coils L1 and L2, also significantly increases). Therefore, in the first to fifth embodiments, the coil L
Due to heat, the shunt ratio of the parallel circuit composed of the coil side circuit and the diode block side circuit between the winding start and the tap between L1 and L2 deviates from the value set to optimize the convergence due to heat. Sometimes.

Therefore, the following sixth to eighth embodiments (FIG. 1)
2 to 14) are temperature compensation circuits 21 and 22 in which the DC resistance decreases due to the temperature rise in order to cancel the DC resistance increase due to the temperature rise in the coil side circuit (the portion between the winding start and the tap). This is provided in series with the coil side circuit. As the temperature compensation circuit, a circuit having a DC resistance characteristic in which the resistance is reduced by an amount corresponding to canceling the DC resistance increase of the coil side circuit is used (that is, a DC resistance characteristic capable of always keeping the shunt ratio of the parallel circuit constant). Is used). The temperature compensation circuit includes, for example, a thermistor M1 having a negative polarity and a fixed resistor R21 as shown in FIG.

The sixth embodiment shown in FIG. 12 is obtained by adding a temperature compensation circuit 21 to the first embodiment shown in FIG. FIG.
The seventh embodiment shown in FIG. 3 is obtained by adding the temperature compensation circuit 22 to the fourth embodiment shown in FIG. In the eighth embodiment shown in FIG. 14, a temperature compensation circuit 21 is provided in the fifth embodiment shown in FIG.

The position where the temperature compensation circuit is provided is the coil L
Any coil-side circuit in a parallel circuit composed of a winding portion (coil-side circuit) from the start of winding of 1, L2 to the tap and a diode block may be used. Taking FIG. 14 as an example, the winding start side of the coil L2 may be between the taps T1S and T2S.

In each of the above embodiments, the saddle type vertical deflection coil is shown as a single pair. However, the saddle type vertical deflection coil may have a plurality of pairs. What is necessary is just to provide in one pair. Further, the diode block may be a zener diode block including a plurality of zener diodes connected in series with opposite polarities.

[0041]

As described above, the deflection yoke according to the present invention can easily correct the reverse pattern of the cross miss convergence, and can achieve both the elimination of the distortion of the raster at the top and bottom of the screen and the convergence, and the convergence quality. It can be greatly improved.

Further, since the deflection yoke can easily correct the reversal pattern by adjusting the turn-on position of the diode block, the reversal pattern is corrected by manually adding a magnetic piece or the like for each deflection yoke as in the prior art. The task of doing so is greatly reduced. Therefore, the deflection yoke of the present invention can improve work efficiency and improve productivity.

The deflection yoke provided with the temperature compensating circuit, in addition to the above-mentioned effects, can cancel the DC resistance change in the parallel portion with the diode block of the vertical deflection coil due to the temperature change. The ratio can always be kept at the optimum value, and the optimum convergence can always be obtained even when the device is used in a high temperature state such as during high frequency operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment.

FIG. 2 is a diagram showing a second embodiment.

FIG. 3 is a current waveform diagram of a frame correction coil.

FIG. 4 is a diagram showing a third embodiment.

FIG. 5 is a diagram for explaining cross miss convergence;

FIG. 6 is a diagram for explaining cross miss convergence.

FIG. 7 is a diagram for explaining cross miss convergence;

FIG. 8 is a diagram showing a fourth embodiment.

FIG. 9 is a diagram showing a magnetic field distribution of a fourth embodiment.

FIG. 10 is a diagram showing a fifth embodiment.

FIG. 11 is a diagram for explaining taps.

FIG. 12 is a diagram showing a sixth embodiment.

FIG. 13 is a diagram showing a seventh embodiment.

FIG. 14 is a diagram showing an eighth embodiment.

[Explanation of symbols]

 D1 to D4 Diode L1, L2 Vertical deflection coil L3 to L6 Frame correction coil R1 to R7 Resistance T1, T2 Tap T1S, T2S Winding start tap T1F, T2F Winding end tap 21, 22, Temperature compensation circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) H01J 29/76

Claims (14)

(57) [Claims] 1. A self-convergence type deflection yoke comprising at least a pair of saddle type horizontal deflection coils and at least a pair of saddle type vertical deflection coils, wherein each winding of the at least one pair of saddle type vertical deflection coils is provided. A tap is provided in the middle, and a diode block including a plurality of diodes connected in parallel with opposite polarities is connected in parallel with the winding between the tap and the beginning of winding of the winding provided with the tap. Characteristic deflection yoke. 2. A self-convergence type deflection yoke comprising at least one pair of saddle type horizontal deflection coils and at least one pair of saddle type vertical deflection coils, wherein each winding of said at least one pair of saddle type vertical deflection coils is provided. A tap was provided in the middle, and a Zener diode block consisting of a plurality of Zener diodes connected in series with opposite polarities was connected in parallel with the winding between the tap and the beginning of the winding provided with the tap. A deflection yoke, characterized in that: 3. The deflection yoke according to claim 1, wherein at least one of a resistor and a coma correction coil is connected in series to said diode block. 4. The deflection yoke according to claim 2, wherein at least one of a resistor and a coma correction coil is connected in series to said Zener diode block. 5. A self-convergence type deflection yoke comprising at least one pair of saddle type horizontal deflection coils and at least one pair of saddle type vertical deflection coils, wherein each winding of the at least one pair of saddle type vertical deflection coils is provided. Are connected at the same potential, and a tap is provided in the middle of each winding of the at least one pair of saddle type vertical deflection coils, and a plurality of diodes connected in parallel with opposite polarities between the taps are provided. A deflection yoke to which a diode block comprising: 6. A self-convergence type deflection yoke comprising at least a pair of saddle type horizontal deflection coils and at least a pair of saddle type vertical deflection coils, wherein each winding of the at least one pair of saddle type vertical deflection coils is provided. Are connected at the same potential, and taps are provided in the middle of each winding of the at least one pair of saddle type vertical deflection coils, and a plurality of Zeners connected in series with opposite polarities between the taps are provided. A deflection yoke to which a zener diode block composed of a diode is connected. 7. A deflection yoke according to claim 5, wherein at least one of a resistor and a coma correction coil is connected in series to said diode block. 8. A deflection yoke according to claim 6, wherein at least one of a resistor and a coma correction coil is connected in series to said Zener diode block. 9. A self-convergence type deflection yoke comprising at least one pair of saddle type horizontal deflection coils and at least one pair of saddle type vertical deflection coils, wherein each winding of the at least one pair of saddle type vertical deflection coils is provided. The winding start side of the cut end is taken as a winding start side tap, the winding end side of the cut end is taken as a winding end side tap, and the winding start side tap of one vertical deflection coil and the other vertical deflection coil are cut. And the winding start side tap of the other vertical deflection coil is connected to have the same potential, and the winding start side tap of the other vertical deflection coil is connected to have the same potential. The winding end of one of the vertical deflection coils and the winding end of the other vertical deflection coil are connected to have the same potential, and the winding of each of the at least one pair of vertical deflection coils is connected. During start, the deflection yoke, characterized in that a diode is connected blocks comprising a plurality of diodes connected in parallel with opposite polarities. 10. A self-convergence type deflection yoke comprising at least one pair of saddle type horizontal deflection coils and at least one pair of saddle type vertical deflection coils, wherein each winding of the at least one pair of saddle type vertical deflection coils is provided. The winding start side of the cut end is taken as a winding start side tap, the winding end side of the cut end is taken as a winding end side tap, and the winding start side tap of one vertical deflection coil and the other vertical deflection coil are cut. And the winding start side tap of the other vertical deflection coil is connected to have the same potential, and the winding start side tap of the other vertical deflection coil is connected to have the same potential. The winding end of one vertical deflection coil and the winding end of the other vertical deflection coil are connected to have the same potential, and each winding of the at least one pair of vertical deflection coils is connected. Between the winding start, the deflection yoke, characterized in that connecting the Zener diode block including a plurality of Zener diodes connected in series to the opposite polarity. 11. The deflection yoke according to claim 9, wherein at least one of a resistor and a coma correction coil is connected in series to said diode block. 12. The deflection yoke according to claim 10, wherein at least one of a resistor and a coma correction coil is connected in series to said Zener diode block. 13. The deflection yoke according to claim 1, wherein the diode block and a winding of the at least one pair of saddle type vertical deflection coils are provided. In the parallel circuit, a temperature compensating circuit in which the DC resistance decreases due to a temperature rise is provided in series on the winding side of the at least one pair of saddle type vertical deflection coils, and the temperature compensating circuit includes the winding in the parallel circuit. A deflection yoke having a DC resistance characteristic for canceling an increase in DC resistance due to a temperature rise in a line portion and maintaining a constant current dividing ratio of the parallel circuit. 14. The deflection yoke according to claim 2, wherein the Zener diode block and a winding of the at least one pair of saddle type vertical deflection coils. In the parallel circuit, a temperature compensating circuit in which a DC resistance is reduced by a temperature rise is provided in series on the winding side of the at least one pair of saddle type vertical deflection coils, and the temperature compensating circuit is provided in the parallel circuit. A deflection yoke having a DC resistance characteristic that cancels an increase in DC resistance due to a rise in temperature of a winding portion and keeps a shunt ratio of the parallel circuit constant.