JPH03247093A - Deflection yoke - Google Patents

Abstract

PURPOSE:To correct nonlinear coma aberration and to correct Yh misconvergence simultaneously by interconnecting diodes and connecting points of correction coils corresponding to the diodes with an impedance element and connecting the parallel connection correction coil group in parallel or in series with a main vertical deflection coil. CONSTITUTION:The Yh misconvergence of a both sides electronic beam is corrected by a current flowing directly via a diode 52 in conduction state to lower side correction coils 35, 36 at upper deflection. On the other hand, a deflection magnetic field opposite to a direction of a magnetic field formed by upper side correction coils 33, 34 is formed via a conductive diode 51 and impedance elements 71, 72 to the upper side correction coils 33, 34 to correct coma aberration and vertical raster distortion. Moreover, the role played by the upper side correction coils 33, 34 and the lower side correction coils 35, 36 is reversed to each other via the conductive diodes 51, 52 at the lower deflection and the similar correction to the upper deflection is implemented. Thus, both the correction of coma aberration and that of Yh misconvergence are simultaneously implemented.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a deflection yoke used by being attached to a color cathode ray tube (hereinafter referred to as CRT) having three electron guns arranged in-line. .

[Prior Art] A deflection yoke used in a CRT having three electron guns in an in-line arrangement generally includes a horizontal deflection coil having a pin magnetic field component and a vertical deflection coil having a barrel magnetic field component. is used.

In a deflection yoke with such a non-uniform magnetic field distribution, when three electron beams are deflected in the vertical direction, the vertical direction of the side electron beams and the center electron beam is affected by the barrel magnetic field distribution. A difference occurs in the deflection sensitivity, and misconvergence called raster coma aberration Q occurs in the upper and lower portions of the screen (F), as shown in FIG. 11, which will be described later.

Since this amount of misconvergence is generally not negligible, some kind of correction means is required.

Further, when focusing on the misconvergence of the electron beams on both sides and averaging the first quadrant of the coordinates with the center of the screen of the CRT as the origin, a misconvergence pattern as shown in FIG. 1O is generally obtained.

In FIG. 10, the misconvergence xh, yh and PQ vcr) shown in the upper part, left and right parts, and part of the corner of the screen (F), that is, xh + Y h + PQv
The value of is usually called the trilemma.

This trilemma is determined by the structure of the deflection yoke, and in many cases it does not become completely zero, resulting in residual trilemma, causing various misconvergence, and in some cases requiring trilemma correction means. .

Conventionally, as a deflection yoke that also serves to correct both coma aberration and trilemma as described above, Japanese Patent Laid-Open No. 61-2537
The one disclosed in Japanese Patent No. 50 is known.

The conventional deflection yoke disclosed in the above publication has a pair of left and right 8-shaped magnetic bodies at its rear, and a total of six auxiliary coils are wound around the middle and both ends of each of these 8-shaped magnetic bodies.
These auxiliary coils are configured to flow a vertical deflection current.

The configuration is such that the direction of the magnetic field generated by the intermediate correction coil is opposite to the direction of the vertical deflection magnetic field, and the direction of the magnetic field generated by the auxiliary coils at both ends is the same as the vertical deflection magnetic field. This is a deflection yoke with a convergence correction function.

Both magnetic fields generated by each of the correction coils act on the center electron beam and both side electron beams so as to produce a difference in deflection force in the vertical direction, so that coma aberration is corrected. Furthermore, the trilemma can also be corrected by arbitrarily adjusting the ratio of both magnetic fields. In other words, when the effect of the magnetic field distribution resulting from the combination of both magnetic fields deflects each electron beam in the same direction as the vertical deflection direction, the trilemma is corrected in the positive direction, and vice versa, the trilemma is corrected in the negative direction. be done.

[Problem to be solved by the invention] Since the conventional deflection yoke is configured as described above,
When arbitrarily setting the coma aberration correction amount and the trilemma correction amount, it is necessary to make complicated adjustments to the number of windings of the auxiliary coil and the shape of the figure-8 magnetic body. Further, in view of the principle of trilemma correction, there is a problem in that when a trilemma is corrected, raster distortion at the top and bottom of the CR7 screen, which is correlated with the amount of trilemma correction, changes.

In addition, the actual coma aberration and YH Miscon 8 error are $
In many cases, it has a non-linear shape as shown in Figures 12 and 13, and in order to flow a sawtooth current for vertical deflection through the correction coil,
When the coma aberration at the edge of the screen and the overall trilemma are corrected, the coma aberration at the intermediate point i of the vertical deflection, Y
There were problems such as over-correction for both h-misconvergence.

This invention was made to solve the above-mentioned problems, and it is possible to correct nonlinear coma aberration and to correct y, which is one component of the trilemma, without changing vertical raster distortion.
It is an object of the present invention to provide a deflection yoke that can simultaneously achieve correction of h-minucomparrence.

[Means for Solving the Problems] The deflection yoke according to the present invention has poles at upper diagonal portions arranged substantially symmetrically with respect to a horizontal axis and a vertical axis perpendicular to the central axis of the color cathode ray tube at the rear portion. and a lower side correction coil with a pole at a lower diagonal position, and at least one diode is connected to a branch path of the upper side correction coil and a branch path of the lower side correction coil, respectively, in opposite directions. and connect the respective branch circuits in series, connect the branch circuits of the respective correction coils in parallel, and connect the connection points of each of the diodes and the corresponding correction coils via an impedance element, A feature characterized in that the parallel-connected correction coil group is connected in series or parallel to the main vertical deflection coil.According to the present invention, during upward deflection, the diode conductive to the lower side correction coil. The Yh misconvergence of the electron beams on both sides is corrected by the current flowing directly through the current, and on the other hand, the direction of the magnetic field created by the top correction coil is changed through the diode and impedance element that are in conduction to the top correction coil. It is possible to correct coma aberration and vertical raster distortion by applying a deflection magnetic field in the opposite direction.

Further, during upward deflection, the roles of the upper side correction coil and the lower side correction coil are reversed through the conductive diodes, so that the same correction effect as during - upward deflection can be performed.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a front view showing the configuration of a correction coil device in a deflection yoke according to an embodiment of the present invention. In the figure, (101) and (102) are a pair of left and right U-shaped magnetic bodies, and They are arranged on both sides of the neck part (2).

(33) and (34) are upper side correction coils, each having a pole at a diagonal position above the horizontal axis (h) in an inline arrangement. (35) and (3B) are lower side correction coils, each having a pole at a lower diagonal position of the horizontal axis (h).

Figure 2 shows the upper side correction coil (33) in the yoke.
, (34) and lower side correction coils (35), (3B)
It is a circuit diagram showing the wiring state of (4) in the same figure.
is a vertical deflection circuit in which a main vertical deflection coil (5) is connected in series and passes a vertical deflection sawtooth current Ima.

Branches (3) of the upper side correction coils (33) and (34)
7) and the lower side correction coil (35), the branch path of (3B) (
38) are connected in parallel with each other and in series with the main vertical deflection coil (5), and the branch paths (37) of the upper side correction coils (33) and (34) are connected with the main vertical deflection coil (5). A diode (51) that becomes conductive when a downward deflection current flows through the main vertical deflection coil (5) is connected in series,
Also.

A diode (52) that becomes conductive when the upper deflection current flows through the main vertical deflection coil (5) is connected in series to the branch path (38) of the lower side correction coil (35) and (3B). There is.

(71) is the first impedance element, and each branch path (
37) and (38) in parallel to the main vertical deflection coil (5). (72) is a second impedance element, which includes the upper side correction coil (33),
(34) and the corresponding diode-1” (51
) and the lower side correction coil (35).

(36) and the corresponding diode (52)
Connect the connection point between the

These Ml and the second impedance element (71)
, (72) are fixed or variable inductors, resistors,
It is composed of circuit elements such as capacitors, or circuit units in which these circuit elements are connected in series or parallel, and the above-mentioned upper side and lower side correction coils (33)
, (34), (35), and (3B), and each of these coils (33), (34), and (35).
, (3B).

Next, the operation of the above configuration will be explained with reference to the current waveform diagram in FIG.

The third vertical deflection coil (5) is connected to the main vertical deflection coil (5) from the vertical deflection circuit (4).
When a vertical deflection current Ima as shown in Figure (a) flows, this vertical deflection current Ima flows through the first impedance element Zp.
(71) is energized.

Now, when the vertical deflection current I is positive, that is, at the time of upward deflection, the upper side correction coil (
33) and (34), the correction current It does not flow.

On the other hand, if the impedance value of the first impedance element (71) is Zp, the value of IvXZp is the same as that of the diode (
52), this diode (52) becomes conductive, and the lower side correction coil current Ib as shown in FIG. 3(b) flows from the diode (52) to the lower side correction coil (35), (3B).

In addition, the lower side correction coil (35) and the diode (52)
A portion of the lower side correction coil current Ibl as shown in FIG.
is divided.

Further, when the vertical deflection current I is negative, that is, during downward deflection, the lower side correction coil (33), (
34), the upper side correction current It as shown in FIG. 3(d)
On the other hand, a part of the upper side correction current Ibl as shown in FIG. 3(e) is shunted to the lower side correction coils (35) and (3G) via the second impedance element (72).

As described above, FIG. 3 shows a graph in which time T is plotted on the horizontal axis and current change is plotted on the vertical axis for one cycle of the vertical deflection current I, that is, from the deflection at the top of the screen to the deflection at the bottom of the screen.

FIG. 11 shows an example of the misconvergence pattern before being corrected by the correction coil device in the deflection yoke, and the comatic aberration Q and Yh misconvergence shown in the figure are - ) has nonlinear characteristics as shown in FIGS. 12 and 13 with respect to the distance from the center.

In other words, if we look at the amount of change in the deflection distance in the vertical direction of the screen, the amount of change is not proportional to the deflection distance, but the amount of change is small up to the middle of the screen.
The amount of change tends to become extremely large toward the periphery of the screen.

Next, an explanation will be given of the operating principle for correcting the nonlinear coma aberration Q and Yh misconception as shown in FIGS. 12 and 13 using the deflection yoke correction coil device having the above configuration.

First, a case where the light is deflected upwards on the screen will be explained.

A correction current Ib flows through the lower side correction coils (35) and (3B) so as to generate a lower side correction coil magnetic field (8) in the direction shown in FIG. Due to such a correction magnetic field (8), the center electron beam G receives a deflection force f1 in the same direction as the vertical deflection, and both side electron beams B and R have horizontal components in opposite directions, respectively. Deflection force f2 in the direction of increasing the distance. Receive f3. Therefore, coma aberration Q is corrected, and Yh misconvergence is also corrected.

Also, at this time, the lower side correction coils (33), (34)
The lower side correction coil magnetic field (9) shown in FIG. Deflection force f21. which is somewhat weak for beams B and H and has a horizontal component in a direction that narrows the distance between electron beams B and H. f31 acts. Therefore, the amount of correction that plays a role in improving coma aberration and upper and lower raster distortion is covered by the shunt current Ibl of the lower side correction coil current Ib, so although the degree of its effect is small, it is effective in improving raster distortion. There is.

Further, since the range in which these correction currents act is limited by the diode (51) and the diode (52), their effect increases as they are deflected toward the upper end of the screen.

When the screen is deflected downward, the lower side correction coil (35) and the diode (52) on the (3B) side become non-conductive, and the lower side correction coil (33), (34) and the lower side correction coil (35) and (3B) are corrected based on the same operating principle as in the case of upward deflection.

As a result of the above operations, coma aberration correction characteristics as shown in FIG. 6 and Yb correction characteristics as shown in FIG. 7 are obtained, which are in relatively good agreement with the respective characteristics shown in FIGS. This makes it possible to obtain good convergence characteristics over the entire screen.

In the above embodiment, the correction coil device is composed of a U-shaped magnetic body and a 4 m long correction coil, but it is not limited to this, and a correction coil that can be separated into two elements, the upper side and the lower side, With this configuration, the same effects as in the above embodiment can be achieved.

In addition, in the above explanation, we have explained a configuration consisting of a U-shaped magnetic body and four correction coils, but as shown in Fig. 8, E-shaped magnetic bodies (201) and (202) are used. and two center correction coils (31
), (32), and this center correction coil (31),
(32)! As shown in the wiring diagram in figure $9, the correction coil group f331 is connected in parallel with the main vertical deflection coil (5).
, (34), +351, and (36) in series or parallel to shunt 1V of vertical deflection current to generate a magnetic field in the opposite direction to the 5 main vertical deflection magnetic field, thereby eliminating comatic aberration. The correction function can be further enhanced.

In addition, in the embodiment shown in FIG. 8, a variable resistor (61) is connected in parallel with the central correction coil (311, (321)
Alternatively, by connecting a variable impedance element (not shown), a difference is created in the vertical deflection forces of the electron beams B and R on both sides, thereby correcting a type of asymmetrical misconvergence called axial misconvergence. Functions can also be added.

Furthermore, in the above embodiment, the diode (51) and the diode (52) are configured with one diode (51) and one diode (52), but as shown in FIG. Since the conductive voltage of 511° (52) becomes higher, the degree of nonlinearity of coma aberration and Yh misconvergence can be adjusted.

In addition, as shown in Fig. 9, by connecting independently variable or identified impedance elements (73) and (74) in parallel to the diode (52), coma aberration and Yh miscompensation can be reduced. The degree of nonlinearity of the bar sense can be adjusted independently during upward and downward deflection.Especially, when the impedance elements (731 and +741 are variable),
It becomes possible to optimally adjust the degree of correction while inspecting the misconvergence pattern on the screen.

[Effects of the Invention] As described above, according to the present invention, a single deflection yoke can perform the two functions of correcting comatic aberration and correcting Yh misconvergence, which is one component of the trilemma. , the design of the deflection yoke can be facilitated. Furthermore, since coma aberration and Yh misconvergence can be corrected nonlinearly, high-quality convergence characteristics can be obtained over the entire screen.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a correction coil in a deflection yoke according to an embodiment of the present invention, FIG. 2 is a wiring circuit diagram of FIG. 1, FIG. 3 is a current waveform diagram for explaining the operation, and FIGS. Fig. 5 is an explanatory diagram of the operating principle using a correction magnetic field, Figs. 6 and 7 are comatic aberration and Yh misconvergence correction characteristics, and Fig. 8 is a correction coil in a deflection yoke according to another embodiment of the present invention. 9 is a wiring circuit diagram of FIG. 8, FIG. 10 is a first quadrant diagram showing an example of a misconvergence pattern, and FIG. 11 is an example of a misconvergence pattern before being corrected. Fig. 12 and 1
FIG. 3 is a diagram showing general characteristics of coma aberration and yh misconvergence in FIG. 11. (2)... Neck of CRT, T4) - Vertical deflection circuit, (5) - Vertical deflection coil, (331, (3
4)...Upper side correction coil, (35), (35) -
・Lower side correction coil. (511, (521-... diode, (71), (
72)--Impedance element, Tl(11), [1
02)...Full-shaped magnetic material. Note that the same symbols in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] (1) In a deflection yoke for an in-line color cathode ray tube, which is equipped with at least one pair of horizontal deflection coils and at least one pair of main vertical deflection coils, each of the horizontal and vertical axes perpendicular to the central axis of the color cathode ray tube is provided at the rear part. An upper side correction coil having a pole at an upper diagonal position and a lower side correction coil having a pole at a lower diagonal position are arranged almost symmetrically, and branch paths and lower side correction of these upper side correction coils are provided. At least one diode is connected in series to each branch of the coil in opposite directions, and the branches of both of the correction coils are connected in parallel, and each of the diodes and the corresponding correction coil are connected in parallel. A deflection yoke characterized in that the connection points of the above are connected via an impedance element, and the parallel-connected correction coil group is connected in series or parallel to the main vertical deflection coil.