JPH11238480A - Deflection yoke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deflection yoke which allows easily correcting the unbalance of the distortions in the upper and lower parts of a screen of a color cathode-ray tube even after mounting thereto and adjustment are completed. SOLUTION: A deflection yoke 5 includes a horizontally deflecting coil and a vertically deflecting coil and is mounted on a color cathode-ray tube for performing deflection of an electron beam, wherein the configuration comprises a permanent magnet 11a to exert an upward directed force to the electron beam and correct the distortion in the upper part of the screen of color cathode- ray tube, another permanent magnet 11b to exert a downward directed force to the electron beam and correct the distortion in the lower part of the screen, a slide mechanism 12a installed in the upper part 5a of the front opening and to slide the magnet 11a to the front and rear centering on the reference position A, and another slide mechanism 12b installed in the lower part 5b of the front opening and to slide the magnet 11b to the front and rear centering on the reference position A. The slide mechanism 12b comprises a plane part 121 and a guide member 122 in an inverted L-shape furnished parallel at the end of the plane part 121.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke used for a color cathode ray tube, and more particularly to a deflection yoke capable of easily correcting vertical distortion of a display screen.

[0002]

2. Description of the Related Art FIG. 3 is a schematic structural view of a color cathode ray tube. In FIG. 3, reference numeral 1 denotes a funnel portion, and 2 denotes a neck portion formed at a rear portion of the funnel portion 1. An electron gun 4 for generating three electron beams 3 is mounted inside the neck portion 2. Outside the funnel unit 1, a deflection yoke 5 for deflecting the electron beam 3 up, down, left and right is arranged. At the front of the funnel 1, a striped phosphor 6 emitting red, green, and blue light inside, and 3
A panel 8 having a shadow mask 7 for selectively projecting the electron beam 3 to each phosphor 6 is mounted.

FIG. 4 is a perspective view showing a deflection yoke. The deflection yoke includes a horizontal deflection coil 9 for deflecting an electron beam in the horizontal direction of the screen and a vertical deflection coil 10 for deflecting the electron beam in the vertical direction of the screen. Each of the horizontal deflection coil 9 and the vertical deflection coil 10 is formed in a saddle shape as shown in FIGS. The horizontal deflection coil 9 and the vertical deflection coil 10 are arranged in a state where the vertical deflection coil 10 covers the outside of the horizontal deflection coil 9 as shown in FIG. Further, permanent magnets 11a and 11b are fixed to upper and lower portions 5a and 5b of the front opening of the deflection yoke 5, respectively. The front opening means an opening on the funnel side when mounted on the color cathode ray tube. The opening on the neck side is the rear opening.
The upper and lower portions of the front opening are also mounted on the color cathode ray tube, with the upper portion being the upper portion and the lower portion being the lower portion.

[0004] The color cathode ray tube to which the deflection yoke 5 is attached as described above is composed of the deflection coils 9 of the deflection yoke 5.
By passing a current through the electron beam 10, the three electron beams 3 from the electron gun 4 are deflected up and down, left and right, hit the phosphor 6 through the holes of the shadow mask 7, and can project an image over the entire screen. In such a configuration, when the maximum value of the current applied to the horizontal deflection coil 9 is always the same and the maximum value of the current applied to the vertical deflection coil 10 is always the same, as shown in FIG. A concave screen distortion occurs in the left and right equal amounts. Next, correction of the screen distortion will be described. The left and right concave distortions can be corrected at the time of operation of the cathode ray tube by providing an operation circuit for changing the deflection current applied to the deflection yoke. However, vertical concave distortion cannot be easily corrected by an operation circuit. Usually, as shown in FIG. 4, a permanent magnet 11 having a strength corresponding to the correction amount is used.
a, 11b are fixed at predetermined positions of the upper part 5a and the lower part 5b of the front opening, and vertical concave distortion is corrected.

FIG. 9 is a diagram for explaining the principle of correcting the concave distortion at the upper and lower portions of the screen. The electron beam 3 deflected upward.
Is upwardly deflected by the force of F by the magnetic field formed by the permanent magnet 11a, and is further deflected upward. The electron beam 3 deflected downward receives a force of F downward by the magnetic field formed by the permanent magnet 11b, and is further deflected downward. Therefore, by setting the strength of the magnet according to the amount of distortion, it is possible to correct the vertical concave distortion. The permanent magnets 11a and 11b are directly fixed to the bobbin 51 of the deflection yoke 5 using an adhesive. Alternatively, a frame in which the magnet is fitted to the bobbin 51 is integrally formed, and the frame is fixed by fitting the magnet into the frame. The correction by the permanent magnets 11a and 11b is limited to a color cathode ray tube having a stripe phosphor structure. This is because, when the trajectory of the electron beam is corrected by the magnet, no color shift occurs even if the beam landing state for the red, green, and blue phosphors changes.

[0006]

In the conventional deflection yoke as described above, the permanent magnets 11a, 11a having a strength corresponding to the correction amount are used.
11b is fixed to a predetermined position of the upper part 5a and the lower part 5b of the opening, and the vertical concave distortion is corrected. However, when the deflection yoke 5 is attached to the color cathode ray tube, the deflection yoke 5 is adjusted by tilting the deflection yoke 5 upward or downward within a gap between the funnel portion 1 and the other components in relation to adjustment of other characteristics. There is a case where it is fixed. Note that tilting up means
By tilting the deflection yoke tightening portion (neck portion side) upward, the gap between the front opening lower portion 5b and the funnel portion 1 is narrowed. In addition, the term “tilt downward” means a state in which the gap between the front opening upper portion 5a and the funnel portion 1 is narrowed by tilting the deflection yoke fastening portion downward. When the deflection yoke 5 is tilted upward, FIG.
On the other hand, when the screen is tilted downward, the screen distortion becomes unbalanced in the vertical direction as shown in FIG. This is due to the fact that the tilt of the deflection yoke 5 changes the magnetic field curve involved in the horizontal deflection of the electron beam 3.

Normally, the inclination of the deflection yoke 5 is basically set so as not to impair the balance of the vertical distortion.
10 and 1 depending on the variation in the assembly accuracy and the adjustment method.
As shown in FIG. 1, distortion unbalance occurs.
However, after the deflection yoke 5 is fixed to the color cathode ray tube, almost no distortion imbalance can be corrected. In addition, the screen distortion may require an adjustment accuracy with a concave amount of 1.0 mm or less, and the adjustment accuracy is quite severe. In the conventional deflection yoke, the permanent magnet is fixed to the upper portion 5a and the lower portion 5b of the front opening as described above to correct the concave distortion at the top and bottom of the screen. Has a problem that the screen distortion cannot be finely adjusted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a permanent magnet for adjusting screen distortion which can be slid back and forth in the tube axis direction, thereby adjusting the attachment to a color cathode ray tube. It is an object of the present invention to obtain a deflection yoke that can easily correct the imbalance of the vertical distortion of the screen even after the completion of the above.

[0009]

SUMMARY OF THE INVENTION A deflection yoke according to the present invention has a horizontal deflection coil and a vertical deflection coil, and is mounted on a color cathode ray tube to deflect an electron beam. A first permanent magnet that exerts a force and corrects distortion at the top of the screen of the color cathode ray tube, a second permanent magnet that exerts a downward force on the electron beam and corrects distortion at the bottom of the screen, and an upper part of the front opening And a first slide mechanism for sliding the first permanent magnet back and forth about the reference position, and a second permanent magnet provided below the front opening and centering the second permanent magnet on the reference position. A second slide mechanism for sliding back and forth.

The horizontal deflection coil and the vertical deflection coil are supported by a bobbin, and the first and second slide mechanisms include a flat portion and an inverted L provided in parallel to an end thereof.
It has a U-shaped guide member and is formed integrally with the bobbin.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIGS. 1A and 1B are explanatory views for explaining the structure of the first embodiment of the present invention. FIG. 1A is a perspective view showing only the upper part of a deflection yoke, and FIG. 1B is a view showing a permanent magnet slide mechanism including a center axis of a coil bobbin. FIG. In FIG. 1, portions denoted by the same reference numerals as those in FIGS. 3 and 4 indicate the same portions. Reference numeral 12a denotes a slide mechanism for the permanent magnet 11a, which comprises a flat portion 121 formed in a flat shape and an inverted L-shaped guide member 122 formed in parallel with the end portion. The slide mechanism 12a allows the magnet 11a to slide back and forth in a range B around the reference position A. Here, the reference position is a position where the concave distortion at the top and bottom of the screen can be corrected when the deflection yoke is not tilted up and down and mounted in a standard state. That is, it is the fixed position of the magnet in the conventional example.

A slide mechanism 12b of the same structure for sliding the permanent magnet 11b also in the lower part 5b of the front opening.
Is formed, the permanent magnets 11a and 11b can slide independently of each other. The sliding direction coincides with the tube axis direction in a state where the tube is attached to the cathode ray tube. The slide mechanism 12 is formed integrally with the bobbin 51 of the deflection yoke from plastic. The guide member 122 has a predetermined thickness as shown in FIG. 1B, but the thickness is omitted in FIG. 1A.

Next, the operation will be described. FIG. 2 is an explanatory diagram for explaining the operation of the first embodiment. First, FIG.
In the case where an unbalanced upper and lower screen distortion occurs as shown in (1), the upper permanent magnet 11a is moved forward (toward the funnel) and the lower permanent magnet 11b is moved backward (toward the neck). Can be corrected. That is, when the permanent magnet 11a is moved forward, as shown in FIG. 2, the distance L between the electron beam 3 deflected to the upper part is shortened, and the magnetic force acts strongly. Therefore, F can be increased according to the principle shown in FIG. 9, and the upper concave distortion of the screen can be corrected. When the permanent magnet 11b is moved backward, the distance between the electron beam 3 and the electron beam 3 deflected downward becomes longer, and the magnetic force acts weakly. Therefore, F shown in FIG. 9 can be reduced, and the lower convex distortion of the screen can be corrected.

In the case where an unbalanced image distortion occurs, as shown in FIG. 11, the lower permanent magnet 11b moves forward (toward the funnel portion) and the upper permanent magnet 11a moves backward (to the neck portion). 2), it can be corrected. That is, when the permanent magnet 11b is moved forward, the interval between the electron beam 3 deflected to the lower side is shortened, and a strong magnetic force acts. Accordingly, F shown in FIG.
Can be increased, and the lower concave distortion of the screen can be corrected. When the permanent magnet 11a is moved backward, as shown in FIG. 2, the interval L between the electron beam 3 deflected upward and the magnetic force is weakened. Therefore,
F shown in FIG. 9 can be reduced, and the upper convex distortion of the screen can be corrected. Permanent magnets 11a, 11b
Since the distortion amount of about 0.5 mm can be corrected if the movable range is about 10 mm, the movable range B of about 10 mm is sufficient.

The deflection yoke according to the first embodiment is
After the slide adjustment is completed so that the permanent magnets 11a and 11b do not move during transportation of a device incorporating the same, for example, a television receiver, the permanent magnets are fixed to the guide member 122 and the flat portion 121 with an adhesive, for example. There is a need. However, the effect that the distortion of the upper and lower portions of the screen can be adjusted during the adjustment adjustment of the deflection yoke 5 is very large. Further, even after the fixing, the adjustment can be performed again by removing the adhesive.

[0016]

As described above, according to the present invention, a deflection yoke which has a horizontal deflection coil and a vertical deflection coil and is mounted on a color cathode ray tube to deflect an electron beam exerts an upward force on the electron beam. A first permanent magnet that corrects distortion at the top of the screen of the color cathode ray tube, a second permanent magnet that applies a downward force to the electron beam to correct distortion at the bottom of the screen, and is provided above the front opening; First
A first slide mechanism for sliding the permanent magnet back and forth about the reference position, and a second slide mechanism provided below the front opening to slide the second permanent magnet back and forth about the reference position. Because it has a slide mechanism of
There is an effect that even after the adjustment of the attachment of the deflection yoke to the color cathode ray tube is completed, the imbalance of the vertical distortion of the screen can be easily corrected.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a color cathode ray tube.

FIG. 4 is a perspective view showing a deflection yoke.

FIG. 5 is a perspective view showing a shape of a horizontal deflection coil.

FIG. 6 is a perspective view showing the shape of a vertical deflection coil.

FIG. 7 is an explanatory diagram showing a positional relationship between horizontal and vertical deflection coils.

FIG. 8 is an explanatory diagram showing a screen distortion pattern caused by a deflection yoke.

FIG. 9 is an explanatory diagram illustrating the principle of correcting the upper and lower concave distortions of the screen.

FIG. 10 is an explanatory diagram showing a distortion pattern generated when the deflection yoke is fixed to the color cathode ray tube by being inclined upward.

FIG. 11 is an explanatory diagram showing a pattern of distortion generated when the deflection yoke is fixed to the color cathode ray tube by being inclined downward.

[Explanation of symbols]

5 Deflection yoke, 5a Upper part of front opening, 5b Lower part of front opening, 9 horizontal deflection coil, 10 vertical deflection coil, 11a, 11b permanent magnet, 12a, 12b slide mechanism, 121 plane part, 122 guide member, A
Reference position.

Claims (2)

[Claims] 1. A deflection yoke having a horizontal deflection coil and a vertical deflection coil and being mounted on a color cathode ray tube to deflect an electron beam, the deflection yoke exerting an upward force on the electron beam, and an upper portion of the screen of the color cathode ray tube A first permanent magnet that corrects the distortion of the electron beam; a second permanent magnet that applies a downward force to the electron beam to correct the distortion at the bottom of the screen; A first sliding mechanism that slides the magnet back and forth about the reference position, and a second slide mechanism that is provided below the front opening and slides the second permanent magnet back and forth about the reference position. A deflection yoke comprising a slide mechanism. 2. A horizontal deflection coil and a vertical deflection coil,
While being supported by the bobbin, the first and second slide mechanisms have a flat portion and an inverted L-shaped guide member provided in parallel with the end portion, and are formed integrally with the bobbin. The deflection yoke according to claim 1, wherein