JPH07193831A - Deflection yoke - Google Patents

Abstract

PURPOSE:To attain correction of YH tilt with a simple operation by connecting an upper mis-convergence correction coil in series with a vertical deflection coil and connecting a lower mis-convergence correction coil in parallel with the vertical deflection coil so as to vary a current flowing to both the coils. CONSTITUTION:When a vertical deflection signal is impressed between terminals a, b of a vertical deflection circuit, three electron beams scan an upper half of a screen for a period T1 and scan a lower half of the screen for a period T2. Since a vertical deflection current flows from the terminal (a) to the terminal (b) for the period T1, a current to an upper mis-convergence correction coil 3a is blocked by a diode D1 and the current flows only to the lower mis- convergence correction coil 3b. Let the direction of the magnetic field produced by the coils 1a, 1b be an arrow MF, then beams B, G, R receive a force shown in an arrow. Thus, the beams B, G, R are shifted upward to correct misconvergence for the upper half of the screen. Conversely, misconvergence is corrected for the lower half of the screen for the succeeding period T2 because the direction of the vertical deflection current flowing between the terminals a, b is reversed.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a correction of misconvergence picture tube of a color television receiver or color display apparatus, and a deflection yoke in particular can be made easily Y _H tilt correction.

[0002]

2. Description of the Related Art In a picture tube, that is, a cathode-ray tube of a television receiver or a display device, a deflection yoke for deflecting an electron beam emitted from an electron gun built in a neck at a rear portion thereof in a vertical direction and a horizontal direction is provided in the neck and the funnel. It is attached to the boundary with. In the deflection yoke, a horizontal deflection coil is wound and mounted in a saddle shape on the inside of a bobbin which is normally spread like a trumpet, and a vertical deflection coil is also wound and mounted in a saddle shape on the outside of the bobbin.

By the way, in a picture tube of a color television receiver or a color display apparatus, that is, a color picture tube, three electron guns are caused due to the assembling accuracy of the picture tube, the assembling accuracy of the deflection yoke, the assembling accuracy, or the remaining design quantity. The electron beams R (red), G (green), and B (blue) emitted from the light sources do not concentrate on one point on the phosphor screen, which causes a color shift and a deterioration in image quality. This electron beam concentration characteristic is called a convergence characteristic and is one of extremely important characteristics for a picture tube.
Among the convergence characteristics, as shown in FIG. 7, the amount of color shift between red (R) and blue (B) in the horizontal direction (Y _H ) on the Y-axis of the screen of the picture tube is called the Y _H tilt (Tilt) characteristic. This has a great influence on the quality of the color image.

Conventionally, as a method of adjusting the Y _H tilt characteristic, the deflection yoke attached to the picture tube is slightly moved up and down to finely adjust the position, and when the proper position is reached, the deflection yoke and the picture tube are adjusted. A method is adopted in which a wedge is inserted at some place between and to fix and a magnetic piece for tilt characteristic correction is attached to the rear enlarged portion of the deflection yoke.

[0005]

Any of the adjustment methods,
Since the work is done while looking at the screen without seeing the hand at the time of work, the former method cannot search for an appropriate position to insert the wedge or check whether the wedge is properly inserted, Also, the latter method requires double-sided tape or adhesive to fix the magnetic piece, and a coma correction coil is attached separately to the rear enlarged part to which the magnetic piece is attached, so the space is small. There is a problem that it is difficult to attach the magnetic pieces, and the adjustment work requires a long time and high skill.

The present invention has been made in view of the above points, and an object of the present invention is to provide a deflection coil capable of Y _H tilt correction with a simple structure and operation without requiring experience or skill.

[0007]

In order to achieve the above object, the present invention provides a first series circuit of an upper side misconvergence correction coil and a diode, and a lower side misconvergence correction coil in series with a vertical deflection coil. And a diode in a second series circuit are connected in parallel, and the diodes in the first series circuit and the diode in the second series circuit are connected so that the conduction directions are opposite to each other, and the upper side misconvergence correction coil is connected. And a current varying means capable of varying the value of the current flowing through the lower misconvergence correction coil.

[0008]

According to the present invention, when the electron beam of the color picture tube is scanning the upper half of the screen, a current flows through the lower misconvergence correction coil and the electron beam is displaced upward due to the above structure. When the beam is scanning the lower half of the screen, a current flows through the upper misconvergence correction coil and the electron beam is displaced downward, so that misconvergence is corrected in the upper half and lower half of the screen, respectively. since displacement of the electron beam when varying the value of the current flowing through the upper misconvergence correction coil and a lower misconvergence correction coil by adjusting the variable current means is changed, it is Y _H tilt correction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 shows a vertical deflection circuit of a deflection yoke according to the present invention.

The vertical deflection circuit includes vertical deflection coils 1a and 1b mounted on the right and left sides of the bobbin of the deflection yoke, respectively, and an upper frame correction coil 2a and a lower frame mounted on a terminal plate at the rear end of the bobbin. The correction coil 2b is connected in series to which a series circuit of the upper misconvergence correction coil 3a and the diode D1 and a lower misconvergence correction circuit 3b and the diode D2 are connected.
And a series circuit of and are connected in parallel. The vertical deflection coils 1a and 1b are connected in series, and a series circuit of two damping resistors R ₁ and a variable resistor VR ₁ for misconvergence correction in the vertical direction (Y _V ) on the Y axis of the screen is connected thereto. It is connected in parallel. In addition, the upper misconvergence correction coil 3a and the lower misconvergence correction coil 3a
b and tilt correction adjusting variable resistor VR ₂ is connected between the variable output terminal of the variable resistor VR ₂ is connected to the terminal b of the vertical deflection circuit. Two diodes D1 and D2
A resistor R ₂ for sensitivity adjustment and prevention of a high-luminance portion is connected between a connection point c and a terminal b.

FIG. 2 shows a well-known deflection yoke, in which saddle type vertical deflection coils 1 and 1b are mounted on the outside of a resin bobbin 5 formed in a trumpet shape.
A two-divided core 6 is attached so as to enclose the vertical deflection coils 1a and 1b. A terminal plate 7 is attached to the outside of the core 6, and the terminal plate 7 is provided with variable resistors VR ₁ and VR ₂ . A rear enlarged portion 8 is provided on the small diameter portion of the bobbin 5, and a horizontal deflection coil (not shown) mounted inside the bobbin 5 is provided on the rear enlarged portion 8.
A groove for winding the lead wire of the vertical deflection coil 1b and a notch for twisting the lead wire are formed. Further, an upper coma correction coil 2a and a lower coma correction coil 2b for expanding the green (G) electron beam in the vertical direction of the phosphor screen (screen) to correct the color misregistration are attached to the rear enlargement portion 8. There is. The upper misconvergence correction coil 3a and the lower misconvergence correction coil 3b newly provided by the present invention are wound around the upper coma correction coil 2a and the lower coma correction coil 2b, respectively, as shown in the cross section in FIG. To be done.

As shown in FIG. 3, 10 is a core of the upper coma correction coil 2a, 11 is a bobbin of the upper coma correction coil 2a, and the upper coma correction coil 2a is wound around the bobbin 11. The upper misconvergence correction coil 3a is wound on it.

Next, the misconvergence correction according to the present invention will be described with reference to FIGS. 4 and 5.

Now, when a vertical deflection signal as shown in FIG. 4 is applied between the terminals a and b of the vertical deflection circuit shown in FIG. 1, the three electron beams are in the upper half of the screen during the period T _1. , And the lower half of the screen is scanned during the period T ₂ . Considering the period T ₁ first, as shown in FIG. 5A, since the vertical deflection current flows from the terminal a to the terminal b during this period T ₁ , the upper misconvergence correction coil 3a is driven by the diode D1. As a result, the current flows only in the lower side misconvergence correction coil 3b. At this time, if the direction of the magnetic field generated by the vertical deflection coils 1a and 1b is the direction indicated by the arrow MF, the electron beam B,
G and R receive the force F indicated by the white arrow. As a result, the electron beams B, G, and R are displaced upward in the figure, so that misconvergence is corrected in the upper half of the screen.

In the next period T ₂ , as shown in FIG. 4, the direction of the vertical deflection current flowing between the terminals a and b becomes opposite, so that only in the upper side misconvergence correction coil 3a during the period T ₁ . Current flows in the opposite direction. At this time, the direction of the magnetic field generated by the vertical deflection coils 1a and 1b is opposite to that in the period T ₁ as shown by the arrow MF, so that the electron beams B, G, and R are directed downwards as shown by white arrows. Receives the force F. As a result, electron beam B,
Since G and R are shifted downward in the figure, misconvergence is corrected in the lower half of the screen.

In any case, if the resistance value is changed by turning the variable resistor VR ₂ provided on the terminal board 7 with a driver, the current value flowing through the upper side misconvergence correction coil 3a and the lower side misconvergence correction coil 3b changes. Therefore, the magnitude of the force F received by the electron beams B, G, and R can be adjusted. As a result, the misconvergence correction amount can be changed between the upper half and the lower half of the screen, which is exactly the adjustment of the Y _H tilt correction amount. Thus, the Y _H tilt correction amount can be adjusted by a simple operation of changing the resistance value of the variable resistor VR _{2 by} a simple adjustment work.

In this embodiment, the upper and lower coma correction coils 2 are used for the above misconvergence correction.
Since the vertical deflection current also flows through a and 2b, sensitivity correction for the green electron beam, that is, coma correction is also performed at the same time.

In the vertical deflection circuit according to the present invention, the current does not flow in the lower misconvergence correction coil 3b when the current is flowing in the upper misconvergence correction coil 3a, and the current is flowing in the lower misconvergence correction coil 3b. The diodes D1 and D2 are connected in series to the respective misconvergence correction coils 3a and 3b so that the current does not flow to the upper misconvergence correction coil 3a when the current is flowing. As shown in FIG. 6, since the current does not flow until a certain voltage (for example, 0.7 V) is applied, the voltage-current characteristic has a misconvergence between the periods T ₁ and T ₂ shown in FIG. There is a period when the correction does not work. Therefore, a high-intensity portion in the horizontal direction is generated at the center of the screen. The resistor R ₂ is connected to prevent this, and a high brightness portion is not generated in the center of the screen by allowing the resistor R ₂ to flow for a short time during which no current flows in the diodes D1 and D2. ing.

According to an experiment conducted by the present inventor, the variable resistor VR ₂ for adjusting the Y _H tilt correction amount is 0 to 20Ω, 1/3 W.
By using the potentiometer of No. ₂ and selecting a resistor of 2Ω for resistance to high brightness of 10Ω and 0.5W, it is possible to perform sufficient Y _H tilt correction and prevent the high brightness part from appearing in the center of the screen. did it.

In the above embodiment, the variable resistor is used to change the value of the current flowing through the upper side misconvergence correction coil and the lower side misconvergence correction coil in order to adjust the Y _H tilt correction amount. For example, a coil having a variable inductor may be used.

[0022]

As described above, according to the present invention,
Since the upper misconvergence correction coil and the lower misconvergence correction coil are connected in parallel in series with the vertical deflection coil, and the current value flowing through the upper misconvergence correction coil and the lower misconvergence correction coil can be changed. allows a very simple operation only on Y _H tilt correction that turn the example of the variable resistor volumes in correcting misconvergence. Therefore, it is no longer necessary to use a magnetic piece as in the past to perform Y _H tilt correction, and the ITC efficiency is improved because the troublesome work of sticking the magnetic piece to a narrow space without seeing the hand is eliminated. . There is no need for adhesives or double-sided tape for attaching magnetic pieces.

According to the present invention, by mounting the misconvergence correction coil on the coma correction coil, the mounting space can be saved and the size can be reduced.

[Brief description of drawings]

FIG. 1 shows an embodiment of a vertical deflection circuit of a deflection yoke according to the present invention.

FIG. 2 is a perspective view of a deflection yoke showing a mounting position of a misconvergence correction coil.

FIG. 3A is a perspective view showing a coma correction coil and a misconvergence correction coil of the deflection yoke according to the present invention;
(B) is the sectional view on the AA line of (a).

FIG. 4 shows a current flowing through a vertical deflection coil.

5A is a diagram illustrating misconvergence correction according to the present invention in the upper half of the screen, and FIG. 5B is a diagram illustrating misconvergence correction according to the present invention in the lower half of the screen.

FIG. 6 shows a voltage-current characteristic of a diode.

FIG. 7 is a diagram illustrating Y _H tilt characteristics of misconvergence that occur in a color picture tube.

[Explanation of symbols]

1a, 1b Vertical deflection coil 2a, 2b Frame correction coil 3a, 3b Misconvergence correction coil 5, 11 Bobbin 6 Core 7 Terminal plate 8 Rear expansion part 10 Core D1, D2 Diode VR ₂ Y _H Variable resistor for tilt correction

Claims (5)

[Claims] 1. A first series circuit of an upper misconvergence correction coil and a diode and a second series circuit of a lower misconvergence correction coil and a diode are connected in parallel in series with a vertical deflection coil. The diode of the first series circuit and the diode of the second series circuit have opposite conduction directions, and the current variable means can vary the current value flowing in the upper misconvergence correction coil and the lower misconvergence correction coil. A deflection yoke having: 2. The deflection yoke according to claim 1, wherein an upper coma correction coil and a lower coma correction coil are connected in series with the vertical deflection coil. 3. The deflection according to claim 2, wherein the upper misconvergence correction coil is wound on the upper coma correction coil, and the lower misconvergence correction coil is wound on the lower coma correction coil. yoke. 4. The deflection yoke according to claim 1, wherein a resistor is connected in parallel with each of the first series circuit and the second series circuit. 5. The deflection yoke according to claim 1, wherein the current varying means is a variable resistor.