JP2009009850A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct a leakage field of a modulator, and restrain image strain without spoiling convergence characteristics. <P>SOLUTION: The display device is provided with horn-shaped magnets 24, 25 at a right upper side and a left upper side of an opening part, corresponding to polar directions of magnets 223, 224 of a modulator 22 fitted on an upper side of the opening part of a deflection yoke. An influence on an electron beam by the leakage field of the magnets 223, 224 can be restrained by the leakage field of the horn-shaped magnets 24, 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device, and is suitably applied to a display device that suppresses image distortion due to a leakage magnetic field from a modulator, for example.

  Conventionally, in a color cathode ray tube, a color image is displayed on a screen by deflecting the traveling direction of an electron beam emitted from an electron gun vertically and horizontally. A deflection yoke having a horizontal deflection coil, a vertical deflection coil, and a core is used for deflecting the electron beam. The deflection yoke is attached to the cone portion from the neck portion of the cathode ray tube to the funnel portion. By this deflection yoke, a horizontal deflection magnetic field and a horizontal deflection magnetic field are formed on the trajectory of the three electron beams emitted from the electron gun, and the electron beam is deflected vertically and horizontally by these deflection magnetic fields.

  In recent years, the performance of cathode ray tubes such as television receivers and computer displays has been required to be highly accurate. In addition, flattening of CRT (Cathode Ray Tube) panels is also progressing. When the CRT panel is flattened, image distortion appears geometrically. In addition, it is difficult to concentrate the three beams at one point.

  Image distortion is improved by disposing a rod-shaped magnet in the opening of the deflection yoke and providing a sub-coil as a coma coil behind the deflection yoke. Convergence can match the X and Y axes only by the magnetic field distribution of the horizontal deflection coil and the vertical deflection coil, as shown in FIG. In order to improve this, a modulator is employed. For example, the modulator is arranged near the top of the screen, and modulates the current flowing through the upper and lower horizontal deflection coils in a vertical period as shown in FIG.

In addition, as a method for correcting misconvergence that occurs in the vertical direction of the screen at a low cost without adversely affecting the convergence characteristics, the horizontal axis of the deflection yoke is paired with the vertical position at equal intervals and substantially parallel to the horizontal axis of the deflection yoke. And a pair of magnetic pieces arranged so as to face each other via the deflection yoke horizontal axis is slidably provided (for example, see Patent Document 1).
JP2003-132819

  By the way, in the display device having such a configuration, in the modulator, a magnetic bias is applied by a strong magnet without modulating the horizontal deflection current with the vertical deflection current. In this way, it is possible to adjust the convergence uniformly on the screen with high accuracy. Due to the leakage magnetic field of the magnet that applies a magnetic bias to the modulator, image distortion occurs on the screen of the display device closer to the side where the modulator is disposed. By flattening the CRT panel, even a slight image distortion can be clearly recognized, and there has been a problem that the quality is significantly deteriorated.

  Further, the invention of Patent Document 1 can correct the vertical misconvergence at low cost, but there is a problem that a method for canceling the influence of the leakage magnetic field from the modulator is not considered.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose a display device capable of suppressing image distortion due to a leakage magnetic field from a modulator without impairing convergence characteristics as much as possible.

  In order to solve such a problem, the display device of the present invention is a display device having a deflection yoke on which a modulation coil that is magnetically biased by a pair of magnets is mounted. Magnetic correction means having a polarity that cancels a leakage magnetic field that adversely affects the image quality of the magnet that applies a magnetic bias to the coil is provided.

  As a result, the leakage magnetic field of the magnet can be canceled out, so that image distortion can be suppressed without damaging good convergence characteristics as much as possible.

  Further, the magnetic correction means can be a set of two corresponding to the magnets.

  Further, the set of magnetic correction means can be arranged at least at the upper end or the lower end of the opening of the deflection yoke where the modulation coil is arranged.

  According to the present invention, the magnetic correction means arranged at the opening of the modulation coil can cancel the leakage magnetic field that adversely affects the image quality of the magnet that applies a magnetic bias to the modulation coil, thereby enabling good convergence characteristics. A display device capable of suppressing image distortion without losing as much as possible can be realized.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) First Embodiment (1-1) Overall Configuration of Cathode Ray Tube In FIG. 1, 100 is a schematic perspective view of a first embodiment of a display device of the present invention as a whole. In FIG. 1, a cathode ray tube bulb 10 as a display device is composed of a panel portion 11, a funnel portion 12, a neck portion 13 and the like. On the inner surface of the panel portion 11, a phosphor screen (not shown) is formed by arranging phosphors of red (R), green (G), and blue (B) in a predetermined pattern.

  Further, an electron gun 14 serving as an electron beam emission source is incorporated in the neck portion 13 of the cathode ray tube bulb 10. Further, a deflection yoke 15 that deflects the electron beam emitted from the electron gun 14 is mounted on the cone portion 25 from the neck portion 13 to the funnel portion 12 of the cathode ray tube bulb 10.

  FIG. 2A is a side view of the cathode ray tube bulb 10 including a partially broken surface of the deflection yoke 15. FIG. 2B is a rear view of the cathode ray tube bulb 10. 2A and 2B, the deflection yoke 15 includes a horizontal deflection coil 16, a vertical deflection coil 17, a separator 18, and a magnetic body core (DY (Deflection Yoke) core) 19. , A ring magnet 20, a coma correction coil (coma coil) 21, a modulator 22, a vertical distortion correction magnet 23, and the like. The horizontal deflection coil 16 is wound inside the separator 18, and the vertical deflection coil 17 is wound outside the separator 18.

  The horizontal deflection coil 16 deflects the electron beam emitted from the electron gun 14 in the horizontal direction (horizontal) of the screen, and the vertical deflection coil 17 directs the electron beam emitted from the electron gun 14 in the vertical direction of the screen. It deflects in the (vertical direction). The horizontal deflection coil 16 is wound around the separator 18 in a saddle shape and is disposed in pairs above and below the deflection yoke 15. The vertical deflection coil 17 is directly wound around the magnetic core 19 and is wound by a so-called toroidal winding method. The magnetic core 19 is used to further increase the efficiency of the magnetic field generated from the deflection coil 15 and is made of a magnetic material such as ferrite.

  The ring magnet 20 is for correcting an assembly error or the like of the electron gun 14 and is attached to the rear end side of the deflection yoke 15.

  FIG. 3 shows the vertical distortion that occurs when the panel portion 11 is flat. It is assumed that the left / right distortion is corrected in advance. This vertical distortion is improved by passing a vertical deflection current through the coma coil 21 shown in FIG. As the vertical distortion is improved, the deterioration phenomenon of convergence characteristics (misconvergence (color shift on the screen)) as shown in FIG. 4 finally remains.

  In order to improve this misconvergence, a modulator (M / D) 22 as shown in FIG. 5 has been devised. The modulator (M / D) 22 includes horizontal modulator coils 221, 222, magnets 223, 224, and a coil 225 through which a vertical deflection current flows.

  The modulator (M / D) 22 is incorporated in a part of the horizontal deflection coil 16 as shown in FIG. The horizontal modulator coils 221 and 222 constituting the modulator (M / D) 22 are modulated by causing a vertical deflection current to flow through the coils 225, respectively, so that the left and right ends of the screen as shown in FIG. Misconvergence at the (corner portion) can be improved.

  Also, as shown in FIG. 5, the modulator 22 is provided with powerful magnets 223 and 224 at the left and right ends, respectively, for applying a magnetic bias. FIG. 7 shows the leakage magnetic field of the magnets 223 and 224 generated corresponding to the polarity of the magnets 223 and 224.

  Generally, the wiring board of the deflection yoke 15 is disposed on the upper side of the deflection yoke 15 for the convenience of manufacturing and the user. In the following description, it is assumed that the modulator 22 is disposed on the upper side of the deflection yoke 15. Needless to say, the same applies to the case where the modulator 22 is disposed below the deflection yoke 15.

  As shown in FIG. 7, due to the leakage magnetic field of the modulator 22, the electron beam is deflected upward at the upper right end of the screen, and the electron beam is deflected downward at the upper left end of the screen. As a result, image distortion (trapezoidal distortion) as shown in FIG. 8 occurs.

  In order to improve the image distortion as shown in FIG. 8, the leakage magnetic field of the magnets 223 and 224 of the modulator 22 may be canceled. Since the magnetic field of the magnets 223 and 224 of the modulator 22 is strong, a cancel magnet that generates a strong magnetic field is necessary to cancel the magnetic field. However, if all the magnetic fields generated by the magnets 223 and 224 are canceled, The objective convergence cannot be improved. In order to improve the image distortion without impairing the convergence characteristics, the square magnet 24 (FIG. 9) may be disposed at a location that greatly affects the occurrence of the image distortion.

  FIG. 9 is a view of the deflection yoke 15 as viewed from the front. Bar-shaped magnets 23 are arranged above and below the deflection yoke 15. Then, square magnets 24 and 25 are respectively arranged on the upper right part and the upper left part of the opening of the deflection yoke 15. The square magnets 24 and 25 are arranged in the opening of the deflection yoke 15 so as to act so as to greatly change the image distortion without largely changing the convergence.

  In this example, in accordance with the polarity of the magnet of the modulator 22, the polarity of the square magnet 25 disposed at the upper left portion of the deflection yoke 15 is the left side for the S pole and the right side for the N pole. The polarities of the square magnets 24 arranged in the upper right part are the N pole on the left side and the S pole on the right side.

(1-2) Operation and Effect In the above configuration, the leakage magnetic fields of the rectangular magnet 24 and the rectangular magnet 25 arranged in the opening of the deflection coil 15 are the leakage magnetic fields of the magnets 223 and 224 of the modulator 22, respectively. It acts to cancel the influence within the range that affects the image distortion. As a result, a display device having good convergence characteristics and image quality with little image distortion can be provided by a structurally simple and inexpensive method. In addition, since the correction amount on the circuit side of the display device can be reduced, the cost can be further reduced.

  FIG. 10 shows the direction of the force that the leakage magnetic field of the magnets 223 and 224 of the modulator 22 and the magnetic field of the square magnets 24 and 25 act on the electron beam. The magnet 223 applies an upward force to the electron beam. On the other hand, the square magnet 24 applies a downward force to the electron beam. As a result, the influence of the leakage magnetic field on the electron beam cancels out. On the other hand, the magnet 224 applies a downward force to the electron beam. On the other hand, the square magnet 25 applies an upward force to the electron beam. As a result, the influence of the leakage magnetic field on the electron beam cancels out.

  In this manner, the influence of the leakage magnetic field of the magnets 223 and 224 of the modulator 22 is canceled by the square magnets 24 and 25, respectively, thereby suppressing the occurrence of image distortion due to the leakage magnetic field of the modulator 22 as shown in FIG. can do.

  According to the above configuration, the leakage magnetic field of the square magnets 24 and 25 disposed in the opening of the deflection yoke 15 can cancel the influence on the electron beam due to the leakage magnetic field of the magnets 223 and 224 of the modulator 22. Generation of image distortion can be suppressed by the magnets 223 and 224 of the modulator 22.

(2) Second Embodiment (2-1) Arrangement Example of Square Magnets FIG. 11 shows an arrangement example of the square magnets 24 and 25 in the second embodiment of the present invention. Since other configurations are the same as those in the first embodiment, the description thereof is omitted. In the case of the second embodiment, the winding direction of the horizontal modulator coils 221 and 222 of the modulator 22 is reversed with respect to the first embodiment, and the polarities of the magnets 223 and 224 are also reversed. ing. Thereby, the polarities of the square magnets 24 and 25 are also reversed.

  That is, according to the polarities of the magnets 223 and 224 of the modulator 22, the polarity of the square magnet 25 arranged at the upper left part of the deflection yoke 15 is the left side of the N pole and the right side of the S pole. As for the polarity of the square magnet 24 arranged in the upper right part, the S pole is on the left side and the N pole is on the right side.

(2-2) Operation and Effect In the above configuration, the leakage magnetic fields of the rectangular magnet 24 and the rectangular magnet 25 arranged in the opening of the deflection coil 15 are the leakage magnetic fields of the magnets 223 and 224 of the modulator 22, respectively. It acts to cancel the influence within the range that affects the image distortion. As a result, a display device having good convergence characteristics and image quality with little image distortion can be provided by a structurally simple and inexpensive method. In addition, since the correction amount on the circuit side of the display device can be reduced, the cost can be further reduced.

(3) Third Embodiment (3-1) Arrangement Example of Square Magnets FIG. 12 shows an arrangement example of the square magnets 24 and 25 in the third embodiment of the present invention. In the case of the third embodiment, the modulator 22 is arranged below the deflection yoke 15 with respect to the first embodiment. The square magnets 24 and 25 are also arranged below the deflection yoke 15 in accordance with the arrangement location of the modulator 22. Since other configurations are the same as those in the first embodiment, the description thereof is omitted. The winding directions of the horizontal modulator coils 221 and 222 are the same as those in the first embodiment, and the magnets 223 and 224 have the same polarity. Accordingly, the polar directions of the square magnets 24 and 25 are the same as those in the first embodiment.

  That is, according to the polarity of the magnets 223 and 224 of the modulator 22 arranged on the lower side of the deflection yoke 15, the polarity of the square magnet 25 arranged on the lower left side of the deflection yoke 15 is N pole on the left side and S pole. Is on the right. As for the polarity of the square magnet 24 arranged in the upper right part, the S pole is on the left side and the N pole is on the right side.

(3-2) Operation and Effect In the above configuration, the leakage magnetic fields of the rectangular magnet 24 and the rectangular magnet 25 arranged in the opening of the deflection coil 15 are the leakage magnetic fields of the magnets 223 and 224 of the modulator 22, respectively. It acts to cancel the influence within the range that affects the image distortion. As a result, a display device having good convergence characteristics and image quality with little image distortion can be provided by a structurally simple and inexpensive method. In addition, since the correction amount on the circuit side of the display device can be reduced, the cost can be further reduced.

(4) Other Embodiments In the above-described embodiment, the case where the square magnets 24 and 25 are used has been described. However, the present invention is not limited to this, and a coil may be used.

  In the above-described embodiment, the present invention is implemented by the square magnets 24 and 25 as magnetic correction means having a polarity that cancels the leakage magnetic field of the magnets 223 and 224 as the first magnets that apply a magnetic bias to the modulation coil. However, the present invention is not limited to this, and the present invention may be configured by other magnetic correction means.

  The display device of the present invention can be applied to, for example, a television receiver and other devices using various CRTs.

1 is a schematic perspective view of a display device according to a first embodiment of the present invention. FIG. 4 is a side view of a cathode ray tube bulb including a partially broken section of a deflection yoke, and a rear view of the cathode ray tube bulb. It is a basic diagram which shows the example of the up-down distortion produced when a panel part is flat. It is a basic diagram which shows the deterioration phenomenon of a convergence characteristic. It is a basic diagram which shows the structural example of a modulator (M / D). 2 is a schematic diagram showing a circuit configuration of a modulator incorporated in a part of a horizontal deflection coil 16. FIG. It is a basic diagram which shows the leakage magnetic field of a magnet. It is a basic diagram which shows the example of image distortion. It is the basic diagram which looked at the deflection yoke from the front. It is a basic diagram which shows the direction of the force which the leakage magnetic field of the magnet of a modulator and the leakage magnetic field of a square magnet act on an electron beam. It is a basic diagram which shows the structural example of the 2nd Embodiment of this invention. It is a basic diagram which shows the structural example of the 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Cathode-ray tube valve, 11 ... Panel part, 12 ... Funnel part, 13 ... Neck part, 14 ... Electron gun, 15 ... Deflection yoke, 16 ... Horizontal deflection coil, 17 ... Vertical deflection coil , 18... Separator, 19... Magnetic core, 20... Ring magnet, 21... Coma correction coil (coma coil), 22... Modulator, 23 ... vertical distortion correction magnet (bar magnet), 24, 25. ... Square magnets, 223,224 ... Magnets, 221,222 ... Horizontal modulator coils, 225 ... Coils.

Claims (3)

A display device having a deflection yoke equipped with a modulation coil magnetically biased by a set of magnets,
A display device comprising: a magnetic correction unit disposed in an opening of the modulation coil and having a polarity that cancels a leakage magnetic field of the magnet that applies a magnetic bias to the modulation coil. The display device according to claim 1, wherein two sets of the magnetic correction means correspond to the magnet. 2. The display device according to claim 1, wherein the set of magnetic correction means is disposed at least at an upper end portion or a lower end portion of the opening of the deflection yoke in which the modulation coil is disposed.