CN1100339C - Cathode ray tube display with littler keystone distortion - Google Patents

Abstract

Provided is a cathode ray tube device capable of correcting vertical or horizontal trapezoidal distortion of a rectangular raster by a simple and inexpensive method of attaching magnets to a deflector so as to obtain good image quality even at the periphery of the screen. The magnet 21 is arranged in a region from the screen-side opening end face 22 of the ferrite core 20 of the deflection yoke located on the rear outer periphery of the cathode ray tube main body 15 to the screen-side end face of the insulating frame 18 . The magnet 21 is arranged such that the magnetic pole direction of the magnet is substantially along the tube axis direction. Furthermore, the magnet 21 is arranged such that the center line of the magnet is located on a plane including the vertical axis of the cathode ray tube main body and the tube axis when correcting the vertical trapezoidal distortion, and on a plane including the horizontal axis of the cathode ray tube main body and the tube axis when correcting the left and right trapezoidal distortion. on the axis plane.

Description

Cathode ray tube display device with small keystone distortion

The present invention relates to the improvement of raster distortion called keystone distortion in cathode ray tube devices (cathode ray tube display devices).

In recent years, in a color cathode ray tube device using a display monitor, it is required that a clear image with little distortion can be observed even at the peripheral portion of the screen. For example, in a personal computer using Windows (Microsoft's operating system), necessary information is frequently displayed on the periphery of the screen. One of the important factors determining the image quality of the peripheral portion of the screen is raster distortion, which is very strictly required. In particular, raster distortion called keystone is a major cause of image quality deterioration, and it is important to overcome it.

As a method of correcting the left and right trapezoidal distortion of a rectangular grating, there is, for example, a method recommended in Mitsubishi Electric Technical Bulletin Vol. In this method, an analog correction current or a digital correction current is generated on the monitor circuit side and superimposed on the deflection current.

However, as described above, when correction is performed on the monitor current side, a complicated and expensive correction circuit for amplitude-modulating the horizontal deflection current during the vertical deflection period is indispensable. Moreover, although the left and right trapezoidal distortion of the rectangular grating can be corrected by this method, the upper and lower trapezoidal distortion cannot be corrected.

The object of the present invention is to provide a cathode ray tube device which corrects vertical or horizontal trapezoidal distortion of a rectangular raster by a simple and inexpensive method of attaching a magnet to a deflection device, and which has good image quality at the periphery of the screen.

In order to achieve this purpose, the cathode ray tube device of the present invention has a first structure which is a cathode ray tube display device, which comprises:

a cathode ray tube body having a glass panel and a glass funnel attached to its rear;

an electron gun disposed at the rear of the above-mentioned cathode ray tube body;

The deflection device arranged on the outer periphery of the rear part of the above-mentioned cathode ray tube body, the deflection device includes a saddle-shaped horizontal coil, an insulating frame arranged outside it, a saddle-shaped vertical coil and a ferrite core arranged outside it, and its characteristics In that: the magnet is provided in a region from the end surface of the screen-side opening of the ferrite core to the screen-side end surface of the above-mentioned insulating frame, the center line of which is located on a plane including the vertical axis of the cathode ray tube main body and the tube axis, and The direction of the magnetic pole is substantially the tube axis direction, and the direction of the magnetic pole is such that it can generate the Lorentz force acting on the electron beam for correcting the upper side or the lower side of the keystone distortion to be parallel to the horizontal axis of the cathode ray tube body.

The second structure is a cathode ray tube display device comprising:

a cathode ray tube body having a glass panel and a glass funnel attached to its rear;

an electron gun disposed at the rear of the above-mentioned cathode ray tube body;

The deflection device arranged on the outer periphery of the rear part of the above-mentioned cathode ray tube body, the deflection device includes a saddle-shaped horizontal coil, an insulating frame arranged outside it, a saddle-shaped vertical coil and a ferrite core arranged outside it, and its characteristics In that: the magnet is arranged in the area from the end face of the screen side opening of the above-mentioned ferrite core to the screen side end face of the above-mentioned insulating frame, the center line of which is located on a plane including the horizontal axis of the cathode ray tube main body and the tube axis, and the magnetic poles The direction of the pole is substantially the direction of the tube axis, and the direction of the magnetic pole is such that it can generate the Lorentz force acting on the electron beam in order to correct the upper or lower side of the keystone distortion to be parallel to the horizontal axis of the cathode ray tube body.

1 is a plan view of a cathode ray tube device according to a first embodiment of the present invention;

2 is a side view of a cathode ray tube device according to a second embodiment of the present invention;

Fig. 3 shows the downward trapezoidal distortion and its correction principle on the upper side of the rectangular grating displayed on the screen of the cathode ray tube;

Fig. 4 shows the left side of the rectangular grating displayed on the cathode ray tube screen, its top wide trapezoidal distortion and its correction principle;

Fig. 5 shows the relationship between the magnetization BV of the magnet and the correction amount ΔV of the downward trapezoidal distortion on the right side on the rectangular grating;

Fig. 6 shows the relationship between the magnetization BH of the magnet and the correction amount ΔH of the upper wide trapezoidal distortion on the right side of the rectangular grating;

Fig. 7 shows the correction amount ΔV of the downward trapezoidal distortion on the right side of the rectangular grating;

FIG. 8 shows the correction amount ΔH of the trapezoidal distortion of the upper width on the right side of the rectangular grating.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is the plan view of the 41cm (17 ") · 90 ° cathode ray tube device of the first embodiment of the present invention. The cathode ray tube main body 15 is made of glass panel part 16 and the glass funnel that is connected in glass panel part 16 rear parts Part 17 constitutes, and the electron gun (not shown in the figure) is arranged on the rear part of glass funnel part 17. By the saddle-shaped horizontal coil (not shown in the figure), the insulating frame 18 that is arranged on the outside of the horizontal coil, is arranged on the insulating frame 18 The deflection device composed of the saddle-shaped vertical coil 19 on the outside and the ferrite core 20 arranged on the outside of the vertical coil 19 is installed on the outer periphery of the rear part of the glass funnel 17. The cross-sectional size is 2 mm in length, 5 mm in width, and 15 mm in length , and the cuboid magnet 21 magnetized along the longitudinal direction is installed on this deflection device. Its installation position is the area on the vertical coil 19 near the screen side upper end face 22 of the screen side of the ferrite core 20. So, the magnet The N pole-side end face 23 of 21 is close to the screen-side upper end face 22 of the ferrite core 20, and the center line of the magnet 21 is located on a plane including the vertical axis of the cathode ray tube body and the tube axis.

At this time, since the magnetic field generated by the magnet 21 on the screen side is the magnetic field BR and BL shown in FIG. 3, according to the above principle, the trapezoidal distortion on the right side of the rectangular grating displayed on the screen can be corrected.

Next, the action of the above-mentioned first structure will be described with reference to FIG. 3. FIG. FIG. 3 shows the situation where the right side downward trapezoidal distortion 1 occurs on the upper side of the rectangular grating 7 displayed on the screen of the cathode ray tube and the principle of three-dimensional correction. As shown in the figure, the magnet 6 is arranged at a place corresponding to the upper side of the cathode ray tube main body, and its center line 5 is located on a plane 4 including the vertical axis 2 of the cathode ray tube main body and the tube axis 3, and the direction of the magnetic poles is approximately the tube axis. Direction, the N pole is facing the electron gun side, and the S pole is facing the screen side. As a result, magnetic fields BR and BL are generated on the screen side. The direction of the magnetic field BR is from the right side of the screen to the center when viewed from the front of the screen, and the direction of the magnetic field BL is from the left side of the screen to the center. The electron beam emitted from the electron gun mainly has the velocity vector from the electron gun to the tube axis direction of the screen, and the electron beam deflected to the upper right of the screen is subject to the upward Lorentz force FR due to the magnetic field BR, and moves to the upper left of the screen. The partially deflected electron beam is subject to the downward Lorentz force FL due to the magnetic field BL. In this way, the downward trapezoidal distortion 1 on the upper side and right side of the rectangular grating 7 is corrected. According to the same principle, it is also possible to correct the upward keystone distortion on the right side of the upper side.

The action of the second configuration will be described below with reference to FIG. 4 . FIG. 4 shows the case where a trapezoidal distortion 8 of upper side width is produced on the right side of a rectangular grating 14 displayed on a CRT screen, and the principle of this correction in three-dimensional representation. As shown in the figure, the magnet 13 is arranged at the place corresponding to the right side of the cathode ray tube main body, and its center line 12 is located on the plane 11 including the horizontal axis 9 of the cathode ray tube main body and the tube axis 10, and the direction of the magnetic pole is generally tube In the axial direction, the N pole is facing the electron chamber side, and the S pole is facing the screen side. As a result, magnetic fields BT and BB are generated on the screen side. Viewed from the front of the screen, the direction of the magnetic field BT is from the upper side of the screen to the center, and the direction of the magnetic field BB is from the lower side of the screen to the center. The electron beam emitted from the electron gun has a velocity vector mainly from the electron gun to the tube axis direction of the screen, so the electron beam deflected to the upper right of the screen is subject to the Lorentz force FT to the left due to the magnetic field BT, and to the screen The deflected electron beam at the lower right part of the surface receives a rightward Lorentz force FB due to the magnetic field BB. In this way, as shown in FIG. 4, the upper wide keystone distortion 8 on the right side of the rectangular raster 14 is corrected. According to the same principle, the lower wide keystone on the right and the keystone on the left can also be corrected.

Fig. 5 shows the relationship between the longitudinal magnetization BV of the magnet 21 of the above-mentioned size and installation position in its longitudinal direction end face and the correction amount ΔV (referring to Fig. 7 ) of the right side downward trapezoidal distortion on the rectangular grating. The magnetization BV is roughly proportional to the correction amount ΔV. It can be seen that the trapezoidal distortion of about 2mm can be corrected with a magnetization BV of 30mT.

Fig. 2 is the side view of the 41cm (17 ") · 90 ° color cathode ray tube device of the second embodiment of the present invention. The cathode ray tube main body 24 is made up of glass panel part 25 and the glass that is connected in glass panel part 25 rear parts. Funnel 26 constitutes, and electron gun (not shown in the figure) is arranged on the rear portion of glass funnel 26.And by saddle-shaped horizontal coil (not shown in the figure), the insulation frame 27 that is arranged on the horizontal coil outside, is arranged on the insulation The saddle-shaped vertical coil 28 on the outside of the frame 27 and the deflection device formed by the ferrite core 29 outside the vertical coil 28 are installed on the rear periphery of the glass funnel 26. The cross-sectional size is 2 mm vertically and 5 mm horizontally, and the length is The rectangular magnet 30 of magnetization along its lengthwise direction of 15mm is installed on this deflector.Its mounting position is near the screen side of the screen side end face 31 of ferrite magnetic core 29 in the area on the insulating frame 27.So, the magnet The N pole-side end face 32 of the magnet 30 is close to the screen-side right end face 31 of the ferrite core 29, and the center line of the magnet 30 is located on a plane including the horizontal axis of the cathode ray tube main body and the tube axis.

At this time, since the magnetic field generated by the magnet 30 on the screen side is the magnetic field BT, BB shown in FIG. 4, the trapezoidal distortion of the upper right side of the rectangular grating displayed on the screen can be corrected according to the above principle.

Fig. 6 shows the relationship between the longitudinal magnetization BH of the magnet 30 in its longitudinal direction end face and the upper wide trapezoidal distortion correction (ΔH) on the right side of the rectangular grating (see Fig. The magnetization BH is roughly proportional to the correction amount ΔH, and it can be known that the 2.5mm trapezoidal distortion can be corrected with the magnetization BH of 30mT.

In the first embodiment, the correction of the right downward trapezoidal distortion on the upper side of the rectangular grating has been described, but when correcting the right upward keystone distortion, the direction of the magnet (the polarity of the magnetic pole) may be the same as in Embodiment 1. The situation is the opposite. Furthermore, in order to correct the lower trapezoidal distortion, it is also possible to similarly arrange the magnets in the lower region of the deflection unit.

As a method of adjusting the keystone correction amount, in addition to the method of changing the magnetization of the magnet as described above, there is also a method of changing the magnet installation position along the tube axis direction. At this time, it can be seen from experiments that the closer the magnet is to the screen side, the smaller the correction amount of the trapezoidal distortion is, and the correction amount is almost zero when it exceeds the screen-side end surface of the insulating frame.

In addition, in the second embodiment, the correction of the upper wide trapezoidal distortion on the right side of the rectangular grating was described, but when performing the correction of the lower wide keystone distortion, the direction of the magnet (the polarity of the magnetic pole) can also be changed from that of the second embodiment. The case is the opposite. Furthermore, in order to correct the keystone distortion on the left, it is likewise possible to arrange the magnets in the left area of the deflection device.

At this time, as a method of adjusting the amount of trapezoidal distortion correction, in addition to the method of changing the magnetization strength of the magnet as described above, there is also a method of changing the magnet installation position along the direction of the tube axis. less. It is also known that the correction amount is almost zero when it exceeds the screen-side end face of the insulating frame.

The reason for disposing the magnet on the screen side close to the screen-side end face of the ferrite core is as follows. That is, when the magnet is completely contained in the area of the ferrite core, the magnetic field generated by the magnet is guided into the ferrite core, and the effect of correcting keystone distortion is lost. However, if a part of the magnet protrudes from the screen-side end surface of the ferrite core to the screen side, it will help to correct the keystone distortion. Therefore, adjusting the axial position of the magnet can adjust the correction amount of trapezoidal distortion by adjusting the length of the magnet portion protruding from the screen-side end surface of the ferrite core to the screen side.

In addition, although the shape of the magnet was made into a rectangular parallelepiped in the above-mentioned embodiment, it is not limited to this shape, For example, it may be cylindrical. It is important that the center line thereof is located on a plane including the vertical or horizontal axis of the cathode ray tube main body and the tube axis, and that the directions of the magnetic poles be arranged substantially along the tube axis.

Furthermore, when the magnet is installed along the outer shape of the vertical coil or the insulating frame, an appropriate magnet holding mechanism can also be provided. At this time, the magnet may be held so that its center line is parallel to the tube axis of the cathode ray tube main body, or the magnet may be held at an appropriate inclination angle.

Furthermore, although the above embodiment has been described as a deflection yoke equipped with a saddle-shaped vertical coil, the vertical coil may be a loop coil, and when a loop vertical coil is used, it may be wound on a ferrite core.

As described above, according to the present invention, the trapezoidal distortion of the rectangular grating can be independently corrected up, down, left, and right by a very simple and inexpensive method of installing a specified magnet on the deflection device in a specified position and direction, and can provide a high-quality display on the screen. A cathode ray tube device with good image quality at the peripheral portion of the face.

Claims (2)

1. A cathode ray tube display device comprising: a cathode ray tube body having a glass panel and a glass funnel attached to its rear; an electron gun disposed at the rear of the above-mentioned cathode ray tube body; The deflection device arranged on the outer periphery of the rear part of the above-mentioned cathode ray tube body, the deflection device includes a saddle-shaped horizontal coil, an insulating frame arranged outside it, a saddle-shaped vertical coil and a ferrite core arranged outside it, and its characteristics In that: the magnet is provided in a region from the end surface of the screen-side opening of the ferrite core to the screen-side end surface of the above-mentioned insulating frame, the center line of which is located on a plane including the vertical axis of the cathode ray tube main body and the tube axis, and The direction of the magnetic pole is substantially the tube axis direction, and the direction of the magnetic pole is such that it can generate the Lorentz force acting on the electron beam for correcting the upper side or the lower side of the keystone distortion to be parallel to the horizontal axis of the cathode ray tube body. 2. A cathode ray tube display device comprising: a cathode ray tube body having a glass panel and a glass funnel attached to its rear; an electron gun disposed at the rear of the above-mentioned cathode ray tube body; The deflection device arranged on the outer periphery of the rear part of the above-mentioned cathode ray tube body, the deflection device includes a saddle-shaped horizontal coil, an insulating frame arranged outside it, a saddle-shaped vertical coil and a ferrite core arranged outside it, and its characteristics In that: the magnet is arranged in the area from the end face of the screen side opening of the above-mentioned ferrite core to the screen side end face of the above-mentioned insulating frame, the center line of which is located on a plane including the horizontal axis of the cathode ray tube main body and the tube axis, and the magnetic poles The direction of the pole is substantially the direction of the tube axis, and the direction of the magnetic pole is such that it can generate the Lorentz force acting on the electron beam in order to correct the upper or lower side of the keystone distortion to be parallel to the horizontal axis of the cathode ray tube body.

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