JPH02142036A - Deflecting yoke with misconvergence correction circuit - Google Patents

Abstract

PURPOSE:To perform correction of misconvergence on a horizontal axis by providing a first and second correction coils alternately opposed to each other sandwiching a deflecting magnetic field, so as to let run correction parabora current of almost ideal wave shape in them. CONSTITUTION:On one side of a deflecting magnetic field, a first correction coil 2 is provided so as to generate a magnetic field in a direction where it is convoluted with the deflecting magnetic field, and on the other side, a second correction coil 3, so as to generate a magnetic field in a direction where it is offset with the deflecting magnetic field, both of the correction coils being connected with a horizontal deflecting coil 1. Between the first correction coil 2 and the second correction coil 3, a correction coil actuation circuit is connected in parallel so as to short-circuit the first correction coil 2 and the second correction coil 3, being turned off when a horizontal deflecting pulse becomes voltage in forward direction. By the short-circuit, current of transient phenomena runs in both of the correction coils 2 and 3, while parabora correction current runs in the first correction coil 2 and the second correction coil 3 for a scanning period. Correction of misconvergence on a horizontal axis can thus be performed with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a deflection yoke with a misconvergence correction circuit that includes means for correcting misconvergence in the horizontal direction on the X-axis of a television screen.

[Conventional technology]

As a correction of the so-called trilemma of the color deflection yoke,
Loss misconvergence correction as shown in FIG. 10, and misconvergence Y caused by horizontal color shift between red R and blue B on the Y axis of the television screen as shown in FIG.

Correction of misconvergence XH caused by a color shift between blue B and red R on the X axis as shown in FIG. 12 has been considered. Conventionally, in general, cross-mistake convergence correction and correction of convergence YH on the Y-axis have been widely carried out, but correction of convergence Xtt on the X-axis is based on the ideal signal for the correction. This has not been done for reasons such as the inability to obtain waveforms.

However, in recent years, the image quality of TV screens has become more sophisticated and the screen size has become larger.As a result, the beam drive has become wider-angle deflection, and in order to improve focus characteristics, the magnetic field distribution of the horizontal deflection coil has to be improved. There is a IIJI direction to make a linear magnetic field. However, if the magnetic field distribution of the horizontal deflection coil is made linear, horizontal misconvergence X on the X-axis inevitably appears, and there is a strong need to correct this.

In order to correct this misconvergence XH,
Connect a correction coil connected to the horizontal deflection coil so that magnetic fields in opposite directions are generated, and apply an ideal parabolic current to the correction coil synchronized with the horizontal deflection pulse as shown by the solid line in Figure 6. It is known that it is good.

By the way, when correcting the misconvergence XIl as shown in FIG. 6, the amount of color shift between red R and blue B increases as the distance from the center of the screen to the left and right increases. Therefore, by passing a parabolic current shown by the solid line through the correction coil, when the beam is swung on the left side of the screen, the blue B electron gun G, the green G electron gun G6, and the red R electrons are arranged inline. Among the electron guns G and G, the sensitivity of the blue B beam emitted from the closer electron gun G1 is higher than the sensitivity of the red R beam emitted from the far electron gun Ga, so blue B is Red R moves toward the center along the X-axis.

As a result, red R and blue B match at the green G position. Similarly, when swinging the beam on the right side of the screen, the sensitivity of the red R beam emitted from the nearby electron gun G1 is greater than the sensitivity of the blue B beam emitted from the electron gun Gl, so the red R is on the X axis. As a result, Blue B moves toward the center along the X axis.
Blue B and red R match at the position of green G. In this way, by making red R and blue B coincide, horizontal misconvergence X and I on the X axis are corrected.

During this correction, as mentioned above, the amount of color shift between red R and blue B increases as it moves away from the center, so the current flowing through the correction coil also has a parabolic current that increases as it moves outward from the center of the screen. By flowing, a perfect X correction will be performed.

However, for boat fishing, it is extremely difficult to make the current flowing through the correction coil an ideal parabola. As a circuit for generating this parabolic current, the circuits shown in FIGS. 7 and 8 can be considered. The circuit shown in FIG. 7 connects a first correction coil 2 and a second correction coil 3 to a horizontal deflection coil 1, generates a parabolic current using the resonance of the resonant circuit, and uses this as a correction current. This is added to the correction coils 2 and 3.

Further, the circuit shown in FIG. 8 connects four saturable coils 4 to a bridge, and attempts to apply the parabolic current generated by this bridge circuit to the correction coil 2.3.

[Problem 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 is a waveform portion between the peaks of the sine waveform as shown by the solid line in FIG. It is the one taken out. As a result, the peak portions 5 at both ends of the waveform become dull, making it impossible to obtain a parabolic current as shown by the chain line, resulting in a problem that accurate misconvergence XH cannot be corrected.

Furthermore, in the circuit shown in Figure 8, since the correction current is generated by a bridge circuit, it is difficult to obtain a balanced waveform on the left and right sides, and the sensitivity of the correction is generally poor (
The problem is that there is no. Of course, the sensitivity can be increased by increasing the number of turns of the correction coils 2 and 3, but in this case, the inductance of the correction coils 2 and 3 becomes larger than necessary, and the deflection current flowing through the horizontal deflection coil 1 decreases. A new problem arises in that the deflection amplitude decreases.

The present invention was made in view of the above circumstances, and its purpose is to provide a deflection yoke with a misconvergence correction circuit that can perfectly correct the misconvergence XN on the X-axis using a nearly ideal parabolic current. It is about providing.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured as follows. That is, the deflection yoke with a misconvergence correction circuit of the present invention has a first correction coil that generates a magnetic field in a direction superimposed on the deflection magnetic field on one side of the deflection magnetic field, and a first correction coil that generates a magnetic field in a direction superimposed with the deflection magnetic field on the other side. Second correction coils that generate magnetic fields in canceling directions are connected to the horizontal deflection coils, and the horizontal deflection pulse becomes a forward voltage between the first correction coil and the second correction coil. The structure is characterized in that a correction coil operating circuit that is turned on and short-circuits the first correction coil and the second correction coil is connected in parallel.

[Effect]

In the present invention, when the horizontal deflection pulse is in the forward direction, that is, when the horizontal deflection pulse is at the pulse rising position during the retrace period, the correction coil operation circuit is turned on and the first correction coil and the second correction coil are turned on. Short circuit. This seat allows the re-correction coil to receive transient phenomena of −(,
A current of A, e 4/(L/l) flows. Here, I and AX are the maximum negative current values of the horizontal deflection currents, time is time, L is the inductance of the correction coil, and R is the resistance value of the correction coil. Due to such a transient phenomenon, a parabolic correction current flows through the first correction coil and the second correction coil during the scanning period, resulting in misconvergence on the X axis of the TV screen due to the ideal current waveform. Corrections are made.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings. 1 to 3 show embodiments of a deflection yoke with a misconvergence correction circuit according to the present invention.

In FIG. 1, the deflection yoke is provided with a pair of horizontal deflection coils on the top side and the bottom side, and when the horizontal deflection coils are driven, a horizontal deflection magnetic field B is generated in the vertical direction. At the left and right positions on the neck side of the deflection yoke 9 with this horizontal deflection magnetic field B in between, a pair of U-shaped cores 6.
7 are arranged facing each other, the first correction coil 2 is wound around the core 6, and the second correction coil 3 is wound around the core 7. As shown in FIG. 2, this re-correction coil 2.3 is connected in series to a parallel circuit of a top side horizontal deflection coil Ia and a bottom side horizontal deflection coil 1b. A diode 8 as a correction coil operation circuit is connected in parallel between the first correction coil 2 and the second correction coil 3 with its anode side facing the horizontal deflection coil side.

The apparatus shown in FIG. 1 has a misconvergence of the type shown in FIG.
This is to correct the type of misconvergence in which the opposite side beam appears outside (hereinafter referred to as under-type misconvergence). It is wound to generate a magnetic field B2 in the opposite direction to the horizontal deflection magnetic field B1, and similarly, when the second correction coil 3 receives a horizontal deflection current, it generates a horizontal deflection magnetic field B1 and a magnetic field B2 when scanning the left side of the television screen. They are wound so that a correction magnetic field B is generated in the same direction.

In this configuration, when a horizontal deflection current flows through the horizontal deflection coils la and Ib, a horizontal deflection pulse voltage shown in FIG. 4(a) is generated across the first correction coil 2 and the second correction coil 3. do. At this time, if the diode 8 is not provided, the sawtooth wave shown in FIG. 4(a) will be generated by the correction coil 2.
It flows to 3. On the other hand, as in this embodiment, by providing the diode 8 in parallel with the re-correction coil 2゜3,
This diode 8 is turned on when the deflection current flowing through the correction coils 2 and 3 becomes negative and maximum, that is, when the horizontal deflection pulse becomes a forward voltage, and the current l shown in FIG. 4(b) is turned on. , flows. In this way, when the diode 8 turns on, the correction coils 2 and 3 become short-circuited, and the transient phenomenon current 1c flows through the re-correction coils 2 and 3.
flows.

The current I3 of this transient phenomenon is expressed as I c = I WAX e - """', where l MAX is the maximum negative deflection current flowing through the correction coil 2.3, and L is the maximum negative deflection current flowing through the correction coil 2.3, and L is the current when the diode 8 is turned on. L is the inductance of the correction coil 2.3, and R is the resistance value of the correction coil 2, 3.As can be seen from this equation, the rise of the transient current ■. As shown in Figure (b), it varies depending on the inductance of the correction coil 2.3.In other words, the smaller the inductance L, the larger the rise, and the larger the inductance L, the smaller the rise of Ic.Therefore, this By setting the inductance of the correction coil 2.3 to an optimum value, an optimum parabola correction current for correcting the misconvergence XN can be obtained.

Next, correction of under-type misconvergence X□ using this correction current will be explained. When scanning the left side of the TV screen, the parabola correction current flows through the second correction coil 3. When the current flows to the first correction coil 2, the upper side of the core 7 becomes the N pole, the lower side becomes the S pole, and the upper side of the core 6 becomes the S pole.
The lower side is each polarized to the N pole and the second correction coil 3. Correction magnetic field B3+ directed from N pole to S pole by first correction coil 2
Bz occurs. As a result, on the left side of the TV screen, the horizontal deflection magnetic field B1 is strengthened by the correction magnetic field B and weakened by B2, so that the sensitivity of the blue B beam emitted from the nearer electron gun Gm is lower than that of the farthest electron gun G. The sensitivity of the red R beam becomes higher than that of the emitted red R beam, so blue B moves outward and red R moves inward.

Then, the blue B beam and the red R beam overlap on the green G beam, and misconvergence x and I on the left side of the screen are corrected.

Next, when scanning the right side of the TV screen, the horizontal deflection magnetic field B1
is directed upward, so the magnetic field B1 is applied to the first correction coil 2.
is strengthened by the correction magnetic field Bχ generated by the second
is weakened by the magnetic field B generated by the correction coil 3 of. As a result, on the right side of the TV screen, the sensitivity of the red R beam is higher than that of the blue B beam, so the blue B beam is directed inward and the red R beam is directed outward. and blue B match at the position of green G, and the misconvergence X8 on the right side of the television screen is corrected. By this correction, the under-type misconvergence X shown in FIG. 12(b) can be effectively corrected.

Furthermore, for the type of misconvergence X11 shown in FIG. 12(a), that is, the misconvergence that causes color shift in the same direction as the electron gun arrangement direction (hereinafter referred to as overtype misconvergence), The correction is performed by the apparatus shown in FIG. In the device shown in FIG. 3, the winding direction of the correction coils 2 and 3 is
The direction is opposite to that shown in the figure, and the direction of the correction magnetic fields Bx, Bs is generated in the opposite direction to that shown in FIG.

With this configuration, when scanning the left side of the TV screen, the red R beam has higher sensitivity than the blue B beam, and when scanning the right side of the TV screen, the sensitivity of the blue B beam is higher than the sensitivity of the red R beam. Therefore, it becomes possible to effectively correct the overtype misconvergence XN shown in FIG. 12(a).

Note that the present invention is not limited to the above-mentioned embodiments, and can be implemented in various ways.

For example, in the above embodiment, the top horizontal deflection coil l
a and the horizontal deflection coil Ib on the bottom side are connected in parallel, but they may be connected in series. Further, although the first correction coil 2 and the second correction coil 3 are connected in series, it is also possible to connect them in parallel.

In addition, in the above embodiment, the correction coil operation circuit is constituted by the diode 8, but when the deflection current flowing through the correction coil 2.3 reaches a negative maximum value, in other words, the correction coil operation circuit generates a horizontal deflection pulse. Other circuit configurations are possible as long as the circuit turns on and shorts the correction coil 2.3 when the voltage is in the forward direction; for example,
As shown in FIG. 5, it is also possible to configure the correction coil operating circuit using transistors.

Further, in the above embodiment, the first correction coil 2 and the second correction coil 3 are provided on the neck side of the deflection yoke, but it is also possible to provide the correction coil 2.3 in any other location. be.

〔Effect of the invention〕

The present invention includes a first correction coil and a second correction coil that alternately generate correction magnetic fields in opposite directions with a deflection magnetic field in between, and these correction coils are connected to a correction coil operating circuit. Since it is configured to control the horizontal deflection magnetic field using an ideal waveform of parabolic current, misconvergence XH on the X-axis of the TV screen
This makes it possible to perform corrections with extremely high precision.

In addition, the correction coil operating circuit can be realized with an extremely simple circuit configuration, such as simply connecting a diode in parallel to the correction coil, thereby simplifying the device configuration and reducing device costs. It becomes possible to significantly increase the

[Brief explanation of the drawing]

FIG. 1 shows an under-type misconvergence X deflection yoke with a misconvergence correction circuit according to an embodiment of the present invention. FIG. 2 is a wiring circuit diagram of a correction coil that corrects misconvergence XH in the same embodiment, and FIG. FIG. 4 is an action explanatory diagram showing an example of the formation of the correction current in this embodiment. FIG. 5 is a circuit diagram showing another example of the structure of the correction coil operation circuit. FIG. Undertype misconvergence on the X-axis of the screen X14
An explanatory diagram showing the relationship between the correction current and the correction current for correcting the misconvergence, FIGS. 7 and 8 are generally considered circuit diagrams for generating the correction current for correcting the misconvergence X8, and FIG. 9 is a waveform diagram showing the correction current generated by the circuit of FIG. 7 in comparison with the parabolic current,
FIG. 10 is an explanatory diagram showing examples of various types of cross-misconvergence, and FIG. 11 shows various types of mis-convergence Y in the horizontal direction on the Y-axis of the television screen. Fig. 12 shows the misconvergence XH on the X-axis of the TV screen, of which Fig. 12 (a
) is an explanatory diagram showing over-type misconvergence XH, and FIG. 12(b) is an explanatory diagram showing under-type misconvergence X□. 1...Horizontal deflection coil, 1a...Horizontal deflection coil on the top side, lb...Horizontal deflection coil on the bottom side, 2.
...First correction coil, 3...Second correction coil, 4
...Saturable coil, 5...Peak portion, 6,7...
- Core, 6a, 6b, 7a, 7b... Legs, 8... Diode, 9... Deflection yoke. 1 leaf, 2 stems

Claims (1)

[Claims] On one side of the deflection magnetic field, there is a first correction coil that generates a magnetic field in a direction superimposed on the deflection magnetic field, and on the other side, a second correction coil that generates a magnetic field in a direction that cancels the deflection magnetic field. A horizontal deflection coil is connected to the first correction coil and the second correction coil is provided between the first correction coil and the second correction coil by turning on when the horizontal deflection pulse becomes a forward voltage. A deflection yoke with a misconvergence correction circuit in which a correction coil operation circuit that shorts out the correction coil is connected in parallel.