JP2002209227A - Landing correction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a landing correction device that can conduct landing correction with high accuracy without side effects. SOLUTION: Landing correction coils each formed nearly rectangular symmetrically in vertical and horizontal directions are placed at mid-positions between corners of a band of a CRT whose aspect ratio is 16:9 and the middle of its long side to correct the landing so as to attain landing correction with high accuracy without side effects. Furthermore, the landing correction coils are shaped nearly rectangular and each landing correction coil is fixed to each degaussing coil at two upper/lower positions of the coils so as to reduce dispersion in the distribution of the landing correction amount by the landing correction coils. Then a display image with high color purity and high quality can be obtained at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a landing correction device that corrects the landing of an electron beam in a 6: 9 cathode ray tube.

[0002]

2. Description of the Related Art The color purity adjustment or purity adjustment of a color cathode ray tube (hereinafter referred to as CRT) is performed by adjusting the R, G and B electron beams correctly after passing through a shadow mask hole.
The adjustment is performed so as to land on the G and B phosphor stripes or dots.

[0003] Purity adjustment eliminates color unevenness,
The adjustment is performed so that the T tube surface can reproduce a uniform color in each single color. If the purity adjustment is imperfect, the raster will not be uniformly white, will be partially colored, and a faithful color image cannot be reproduced.

[0004] Most color CRTs have a shadow mask, and the shadow mask tube tends to change its purity under the influence of an external magnetic field such as terrestrial magnetism. Many CRT tubes have a magnetic shield inside the tube, but it is necessary to demagnetize the magnetic shield by applying an attenuated alternating magnetic field to the magnetic shield regardless of inside or outside the tube.

[0005] Purity is adjusted by rotating a purity magnet (two-pole magnet) attached to the outside of the CRT neck at the center of the screen, and by a deflection yoke at the periphery of the screen (EW). Is moved in the front-back direction (tube axis direction) for adjustment.

Further, for the four corners of the screen,
Landing correction is performed using a landing correction magnet as shown in FIG. FIG. 10 shows an example of attaching the landing correction magnet.
This landing correction magnet is a sheet magnetized on NS, and is bonded to the tube surface of the CRT 16.

FIG. 10 is a view of the CRT 16 as viewed from the rear. The landing correction magnet of FIG. 9 is attached to the position shown by arrows E to H near the periphery of the deflection yoke (DY) 15. I have.

In this case, as the landing correction magnet is attached to the deflection yoke (DY) 15 as the landing correction amount increases, the quality of deflection distortion and convergence tends to decrease.

This is because the NS-magnetized landing correction magnet is partially adhered to the funnel portion of the CRT 16 to perform the correction. As shown in FIG. 11, the shift amounts of the electron beams are not uniform but different. It is caused by that.

[0010] Also, for correction of the four corners around the screen,
In some cases, landing correction is performed using a landing correction coil. FIG. 7 shows an installation example of the landing correction coil. When a current flows through the landing correction coil, a correction magnetic field is generated to perform the landing correction.

In this case, the distribution of the landing correction changes from the set value depending on the accuracy of the shape and the mounting accuracy when processing the landing correction coil, and the distribution of the landing deviation depends on the mounting position of the landing correction coil. Because the distribution of the landing correction does not match, there are portions that are over-corrected and portions that are insufficiently corrected, and it is difficult to perform highly accurate landing correction.

[0012]

As described above, when the landing correction magnet which is magnetized by NS is pasted and the landing correction is partially performed, the quality of deflection distortion and convergence is increased as the amount of landing correction increases. However, there is a problem that the temperature tends to decrease.

Further, when the landing is corrected using the landing correction coil, the distribution of the landing deviation on the screen, the landing correction coil, and the distribution of the landing deviation depending on the machining accuracy of the landing correction coil, the mounting accuracy, or the mounting position of the landing correction coil. The distribution of the landing correction amount due to does not match, overcorrected parts,
There were places where the amount of correction was insufficient.

In particular, in recent years, the number of CRTs having a screen size of 16 to 9 has increased, and at the same time, with the increase in the screen size of the CRT, the increase in the definition of the CRT, and the increase in the deflection angle of the CRT, the landing has increased The shift has become noticeable.

In view of the above problems, the present invention can perform landing correction without deviating distortion and adverse effects such as impairing convergence quality. It is an object of the present invention to provide a landing correction device in which the distributions of the correction amounts are consistent, the variation is small, and the landing correction can be performed with high accuracy.

[0016]

According to a first aspect of the present invention, there is provided a landing correction device for detecting a landing deviation of an electron beam in a cathode ray tube having a screen size of 16 to 9 by a landing correction coil. In a landing correction device for correcting, between a corner portion of the reinforcing band of the cathode ray tube and a center portion of a long side of the reinforcing band, three-quarters of a point from a corner portion of the reinforcing band. The landing correction coil is disposed symmetrically in the vertical and horizontal directions of the cathode ray tube so that the center of one side of the landing correction coil is located between the points, and the landing correction of the electron beam is performed.

A landing correction device according to a second aspect of the present invention is the landing correction device according to the first aspect, wherein a landing deviation of an electron beam in a cathode ray tube having a screen size of 16 to 9 is corrected by a landing correction coil. The landing correction coil is formed in a substantially quadrangular shape so as to eliminate variation in the correction amount due to variation in the shape of the landing correction coil.

According to a third aspect of the present invention, there is provided the landing correction device according to the first aspect, wherein the means for fixing the landing correction coil is arranged vertically and horizontally symmetrically. With respect to the coil, at both ends of one side of the landing correction coil on the reinforcing band of the cathode ray tube, two places are fixed to degaussing coils on the reinforcing band of the cathode ray tube, respectively, and the landing on the funnel of the cathode ray tube is performed. The two ends of the other side of the correction coil are also fixed to the degaussing coil on the funnel of the cathode ray tube.

Further, the landing correction device according to a fourth aspect of the present invention is characterized in that, in the first aspect, a driving circuit for supplying a correction current to the landing correction coil is provided.

[0020]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a perspective view showing a state in which landing correction coils 1 to 4 according to an embodiment of the present invention are attached to a CRT 0 having a screen size of 16 to 9. In this case, as an example, upper and lower split type degaussing coils 5 and 6 and landing correction coils 1 to 4 are installed on a 32-inch CRT 0 having a screen size of 16 to 9 and a deflection angle of 120 degrees.

As shown in FIG. 1, from the upper and lower long side band portions 20 of the CRT 0 to the vicinity of one-fourth of the funnel portion 21, the demagnetizing coils 5, 6 extend along the respective rings.
In addition, between the corner part of the CRT0 and the center part of the upper and lower long sides, between the quarter point and the three-quarters point from the corner part of the CRT0, a substantially quadrangle is vertically and horizontally symmetrical with respect to the CRT0. Landing correction coils 1 to
4 is arranged so that the center of one side thereof comes to the center.

In this case, the degaussing coils 5 and 6 for eliminating the influence of the geomagnetism and the like on the external magnetic field are of the upper and lower two-split type. The landing correction coils 1 to 4 are composed of demagnetizing coils 5 and 6 using an adhesive tape and landing correction coils 1 and 2.
4 are fixed at two places, respectively, above and below.

FIG. 2 is a view showing the dimensions of the landing correction coils 1 to 4 in FIG. The shape of the landing correction coils 1 to 4 is substantially quadrangular, and the strength of the magnetic field for correcting landing changes depending on the length in the lateral direction. The length in the vertical direction is determined so that it can be fixed to the demagnetizing coils 5 and 6. If the length in the vertical direction is longer than the length in the horizontal direction, there is no particular problem, and there is no effect on landing correction.

In this example, a landing correction coil having an inner size of 110 mm × 170 mm is used. In addition, as shown in FIG.
When mounted on the CRT0, they are arranged in a bow from the band 20 to the funnel 21 so as to conform to the shape of the CRT.

FIGS. 3 and 4 show the positions of the landing correction coils 1 to 4 when viewed from the top of the CRT 0 and when viewed from the back, respectively.

The degaussing coils 5 and 6 are arranged so as to be as close as possible to the upper, lower and side surfaces of the CRT 0. The degaussing coils 5 and 6 are fixed with an adhesive tape or a plastic runner 7, for example. are doing.

The landing correction coils 1 to 4 are provided between the portions of the degaussing coils 5 and 6 on the CRT band and the portions on the funnel, and further, at a position 80 mm from the center of the long side of the CRT0. The coils are arranged so that the ends of the coils 1 to 4 come.

The fixing of the landing correction coils 1 to 4 and the degaussing coils 5 and 6 will be described by taking the landing correction coil 1 as an example. To fix the landing correction coil 1 and the degaussing coils 5 and 6, an adhesive tape is used. And
In order to fix the shape and arrangement of the landing correction coil 1, as shown by arrows A to D in FIG. 3 and arrows A to D in FIG.
It is fixed to 6. Here, arrows A to D in FIG.
Arrows AD show the same part at different angles.

Here, the conventional landing correction will be described. Normally, the screen size of a 16 to 9 CRT, 4
Landing deviation of the corner is largest at the corner as shown in FIG. 5, and becomes radial at the vertex. this is,
This is because, when the scanning distance of the electron beam becomes longer and the angle at which the electron beam enters the mask becomes acute, the displacement of the landing becomes larger.

Here, since the peripheral portions (EW portions) on the left and right sides of the screen can be adjusted by the attachment position of the deflection yoke (DY), the distribution of the landing deviation as shown in FIG. 5 is obtained. For this landing deviation, NS
When a magnetized landing correction magnet is used, as shown in FIG. 6, in order to perform correction with a small magnetic force of the landing correction magnet 17, the landing correction magnet is moved to a position close to the electron gun 18, that is, the deflection yoke. (DY) 8 is arranged near the opening.

However, in this case, since a uniform correction magnetic field is not applied to the R, G, and B electron beams 19, the quality of deflection distortion and convergence tends to deteriorate as the landing correction amount increases. Occurs.

FIG. 8 shows the distribution of the amount of landing correction when landing correction is performed on a CRT having a screen size of 16 to 9 using a conventional landing correction device as shown in FIG.

Here, the cause of the distribution of the landing correction amount as shown in FIG. 8 will be described. As described above, as the electron beam of the CRT moves toward the corner of the screen, the scanning distance of the electron beam becomes longer, and the electron beam enters the mask at an acute angle.
Extremely large displacement occurs.

This is because the landing correction coils 11 to 1
The same is true when the correction magnetic field of No. 4 affects the electron beam. In other words, the longer the scanning distance of the electron beam and the sharper the angle at which the electron beam enters the mask,
This is because the electron beam is strongly affected by the magnetic field generated by the landing correction coil.

When a correction is made on a CRT having a screen size of 16 to 9 using the conventional landing correction device using a landing correction coil, the electron beam is generated by the magnetic field generated by the landing correction coils 11 to 14. The influence is exerted on the periphery of the mask, that is, in a portion where the distance between the R, G, and B electron beams is very short as shown in FIG. And the landing correction coils 11 to 14
Since the magnetic field generated has a uniform and smooth distribution, there is no deflection distortion or degradation in convergence that occurs when the landing correction is performed using the landing correction magnet.

However, as can be seen from FIGS. 5 and 8,
Since the distribution of the landing deviation does not match the distribution of the landing correction amount by the landing correction coil, a portion where the landing correction is overcorrected or a portion where the correction is insufficient are generated.

At the same time, since the landing correction coils 11 to 14 are arranged at the corners of the CRT 10 as shown in FIG. 7, the landing correction coils 11 to 14 have a curved shape. In this case, variations tend to occur, and the variations affect the distribution of the landing correction amount, so that accurate landing correction cannot be performed.

Next, the case where the shape and arrangement of the landing correction coil is as shown in FIG. 1 will be described. As described above, in the conventional landing correction device in which the landing correction coils are arranged at the corners of the CRT, the distribution of the landing deviation does not match the distribution of the landing correction amount in the CRT having a screen size of 16 to 9.

Therefore, as shown in FIG. 1, the positions of the landing correction coils 1 to 4 are moved toward the center from the corners of the conventional CRT. Specifically, as described above, between the corner portion of the reinforcing band of the CRT and the center portion of the long side of the reinforcing band, a point of a quarter to a quarter of the corner of the reinforcing band. The landing correction coil is arranged so that the center of one side of the landing correction coil is located therebetween.

The distribution of the landing deviation changes depending on the characteristics of the CRT and the position of the deflection yoke at the time of the purity adjustment. Therefore, it is necessary to adjust the position of the landing correction coil so that the correction magnetic field of the landing correction coil matches the distribution of the landing deviation according to the change.

As described above, the position of the landing correction coil is between the corner of the reinforcing band of the CRT and the center of the long side of the reinforcing band, and a quarter of a point from the corner of the reinforcing band. Adjust between 3 points.

The distribution diagram shown in FIG. 12A shows a case where the center of one side of the landing correction coil is located at a quarter point from the corner of the reinforcing band. The ratio of the amount of landing movement due to the correction magnetic field is set to 1
It is shown as 00%.

Similarly, FIG. 12 (c) shows the correction magnetic field of the landing correction coil when the center of one side of the landing correction coil is positioned at three-quarters from the corner of the reinforcing band. 100% for the corner part
It is shown as%.

FIG. 12B is a diagram showing the ratio of the amount of movement of the landing due to the correction magnetic field of the landing correction coil in the case of this example, with the corner portion being 100%.

Since the distribution of the landing deviation after the purity adjustment is approximately within the range shown in FIGS. 12A to 12C, the position of the landing correction coil is determined by the position of the reinforcing band of the CRT as described above. Between the corner and the center of the long side of the reinforcement band, between the point of one-fourth and three-quarters of the corner of the reinforcement band, the position of the center of one side of the landing correction coil; Become.

In this manner, when the landing correction coil is arranged, the effect of the landing correction coil on the EW portion of the screen shown in FIG. 8 is different from the case where the landing correction coil is arranged at the corner of the conventional CRT. By reducing the magnetic field and increasing the correction magnetic field exerted near the upper and lower central portions of the screen, the distribution of the correction magnetic field can be adjusted, and the distribution of the landing correction amount can be made to match the distribution of the landing deviation.

Then, the shape of the landing correction coil is changed from that of the conventional complicated shape including a curve having a large processing variation.
By making it a simple approximately quadrangle with little processing variation,
The variation of the distribution of the landing correction magnetic field due to the shape is suppressed, and the distribution of the landing correction amount is constantly stabilized.

The upper and lower sides of the landing correction coil, which have the greatest effect on the distribution of the landing correction magnetic field,
The demagnetizing coils 5 and 6 whose shapes and arrangements are stable are fixed at both left and right ends of the upper and lower sides of the landing correction coil so that the lengths of the sides of the landing correction coil do not vary, thereby further reducing the variation. It is possible to make the landing correction with higher accuracy by reducing the number.

As described above, according to the configuration in which the landing correction coil is provided as shown in FIG. 1, by accurately correcting the landing deviation at the peripheral portion of the screen, a high-quality display screen with high color purity is obtained. be able to.

[0050]

As described above, according to the landing correction device of the present invention, the screen size of a 16 to 9 CRT is
Between the corner of the reinforcement band and the center of the long side of the reinforcement band, between one-fourth and three-quarters of the corner of the reinforcement band. Approximately 4
The landing correction can be performed without distorting the deflection distortion and the convergence quality by arranging the rectangular landing correction coil and performing the landing correction.

Further, by making the distribution of the landing deviation coincide with the distribution of the amount of landing correction by the landing correction coil, it is possible to perform highly accurate landing correction.

Further, by making the shape of the landing correction coil substantially quadrangular and fixing the landing correction coil to the degaussing coil at two positions above and below the landing correction coil, it is possible to reduce the variation in the distribution of the landing correction amount of the landing correction coil. Therefore, a high quality display screen with high color purity is always obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a landing correction device according to the present invention.

FIG. 2 is a diagram showing a form of a landing correction coil according to the present invention.

FIG. 3 shows a landing correction coil according to the present invention using a CR.
Top view explaining the state attached to T

FIG. 4 shows a landing correction coil according to the present invention using CR.
Rear view explaining the state attached to T

FIG. 5 is an explanatory diagram showing a distribution of landing deviation of a CRT having a screen size of 16 to 9;

FIG. 6 is an explanatory diagram showing the effect of a magnetic field generated by a landing correction magnet and a landing correction coil on R, G, and B electron beams.

FIG. 7 is a rear view showing an example of a landing correction device having a conventional landing correction coil.

FIG. 8 is an explanatory diagram showing a distribution of a landing correction amount by a landing correction device having a conventional landing correction coil.

FIG. 9 shows a landing correction magnet.

FIG. 10 is a rear view of the CRT illustrating a state where the landing correction magnet is attached to the CRT.

FIG. 11 is a diagram illustrating the effect of a landing correction magnet on an electron beam.

FIG. 12 is a distribution diagram showing a distribution of a correction amount by a landing correction coil when a corner portion is set to 100% in a case where the upper right portion of a 16: 9 CRT screen is taken as a representative.

[Explanation of symbols]

 0 CRT with a screen size of 16: 9 1 Landing correction coil 2 Landing correction coil 3 Landing correction coil 4 Landing correction coil 5 Degaussing coil 6 Degaussing coil 7 Plastic runner 8 Deflection yoke (DY) 10 CRT 11 with a screen size of 16: 9 Conventional landing correction coil 12 Conventional landing correction coil 13 Conventional landing correction coil 14 Conventional landing correction coil 15 Deflection yoke (DY) 16 CRT with 16 to 9 screen size 17 Landing correction magnet 18 Electron gun 19 Electron beam R , G, B 20 bands 21 funnels

Claims (4)

[Claims] 1. A landing correction device for correcting a landing deviation of an electron beam in a cathode ray tube having a screen size of 16 to 9 by a landing correction coil, wherein a corner portion of a reinforcement band of the cathode ray tube and a long side of the reinforcement band. Between the center of one side of the landing correction coil and the center of one side of the landing correction coil between a point one quarter and a point three quarters from the corner of the reinforcing band. A landing correction device, wherein the landing correction coils are arranged symmetrically to perform landing correction of an electron beam. 2. A landing correction device for correcting a landing deviation of an electron beam in a cathode ray tube having a screen size of 16 to 9 by a landing correction coil so as to eliminate variation in correction amount due to variation in shape of the landing correction coil. A landing correction device, wherein the landing correction coil is formed in a substantially quadrangular shape. 3. The landing correction device, wherein the means for fixing the landing correction coil is arranged symmetrically in the vertical and horizontal directions with respect to each of the landing correction coils and the landing correction coil on a reinforcing band of the cathode ray tube. At both ends of one side, two places are fixed to the degaussing coil on the reinforcing band of the cathode ray tube, respectively, and both ends of the other side of the landing correction coil on the funnel of the cathode ray tube are also two places of the cathode ray tube respectively. A landing correction device fixed to a degaussing coil on a funnel. 4. The landing correction device according to claim 1, further comprising a drive circuit for supplying a correction current to said landing correction coil.