JPH0370334B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a misconvergence correction method particularly suitable for high-quality picture tubes.

Recently, computer-applied equipment has been trending toward mass adoption, but on the other hand, it has also seen remarkable progress in becoming more sophisticated. Color picture tubes used as displays for computer terminals are no exception. For example, when three electron beams for red, blue, and green are focused on the entire surface of a phosphor screen, the misconvergence, that is, the misconvergence, can be achieved to about 0.5 to 0.6 mm with a 14-inch picture tube ( (Hereinafter, this level will be referred to as the B1 level for convenience), but picture tubes for computer terminals have even stricter requirements than this, and the misconvergence limit is 0.3.
~0.4mm (hereinafter, this level will be referred to as the B2 level for convenience). However, in reality, B1 above
Even when achieving this level, extraordinary consideration must be given to manufacturing variations in deflection yokes, variations in picture tubes, etc.

FIG. 1 shows the configuration of a conventional color picture tube for realizing such a B1 level. In the figure, a picture tube 1 includes a panel 2 having a phosphor screen 3 formed on its inner surface, a net 6 having a built-in electron gun 5 that emits an electron beam that causes the phosphor screen 3 to emit light, and connecting the panel 2 and the net 6. It consists of funnel 4. An assembly (hereinafter referred to as CP) 7 consisting of a two-pole color purity correction magnet 7A and four-pole and six-pole static convergence magnets 7B and 7C is provided on the outside of the funnel 4. A deflection yoke 9 is fitted onto the cone portion 8 . In addition, 13 is the fluorescent screen 3
It is a shadow mask placed opposite.

Next, convergence adjustment of the picture tube configured as described above will be explained. First, in order to match the light source position when burning the phosphor screen 3 with the center of deflection by the electron beam, the three electron beams are moved by the two-pole color purity correction magnet 7A to match the imaginary light source position. . At this time, the static convergence magnets 7B and 7 are set so that the three electron beams are correctly focused at the center of the phosphor screen 3.
Make adjustments with C. If necessary, adjustment may be made to align the deflection center of the electron beam with the imaginary light source position. Next, the deflection yoke 9 is moved along the picture tube axis in order to match the imaginary light source position and the electron beam over the entire surface of the phosphor screen 3. Once the deflection yoke 9 is fixed at the optimum position, in order to obtain even better convergence over the entire surface of the phosphor screen 3, the opening of the deflection yoke 9 on the phosphor screen 3 side is slightly swung. ” In this way, convergence optimization is performed.

By the way, if we consider the causes of misconvergence, we can find the following: movement of the shadow mask 13 after the phosphor screen 3 is printed, deformation of the shadow mask 13, misalignment between the panel 2 and funnel 4, assembly error of the electron gun 5, and misalignment of the electron gun 5. The main causes on the picture tube 1 side are errors in sealing to the tube 6, and causes on the deflection yoke 9 side include variations in the distribution of the horizontal and vertical coils, and errors when combining the horizontal and vertical coils. , the precision of the separator that separates the horizontal and vertical coils, etc. Considering these points, we can understand how difficult it is to achieve the above-mentioned level of B1 even with a 14-inch picture tube, as a result of the combination of variations in the picture tube 1 and variations in the deflection yoke 9. be done.

However, this level of B1 has been achieved somehow by the following method. Simply put, this method is a method in which convergence adjustment is performed with the picture tube 1 and the deflection yoke 9 combined. In other words, rather than thinking about reducing the variations in the picture tube 1 and deflection yoke 9 alone, we take the picture tube 1 we are about to adjust, attach the deflection yoke 9 and cp7, and then adjust the magnetic field that creates the deflection yoke 9. By adjusting B1
It is much more efficient and accurate to achieve this level.

FIGS. 2A and 2B show a conventional deflection yoke 9 used in such convergence adjustment. A magnetic piece 10 such as a ferrite sheet, permalloy, or rubber magnet is attached to the end of the deflection yoke 9.
is attached to adjust the magnetic field distribution, thereby making it possible to achieve the B1 level. Although not shown, a magnetic piece 10 is also attached to the inner surface of the deflection yoke 9, that is, the surface that comes into contact with the cone portion 8. Such a magnetic piece 10 may be magnetized in advance, or even if it is not magnetized, it may be used in accordance with the tendency of misconvergence on the phosphor screen 3 so as to change the distribution of the magnetic field generated by the deflection yoke 9. , the inner surface of the deflection yoke 9, the creeping surface near the opening, or a part of the molded product at the rear thereof have been affixed as appropriate by trial and error without determining the affixing location. However, this method has the disadvantage that it takes a very long time to obtain a certain level of convergence.

This invention was made to eliminate the above-mentioned drawbacks of the conventional technology, and it is possible to quickly and efficiently correct convergence variations around the screen to obtain high-quality convergence characteristics. The purpose of the present invention is to provide a method for correcting misconvergence of a picture tube without impairing the image quality.

Embodiments of the present invention will be described below based on the drawings. 3A and 3B show examples of deflection yokes used in the misconvergence correction method of the present invention. In this figure, the same or corresponding parts as in FIG. 2 are given the same reference numerals. Reference numeral 11 denotes storage ribs provided along the outer periphery of the deflection yoke 9. In this embodiment, the storage ribs 11 are provided at eight equally spaced locations. An unmagnetized magnetic piece 10 is stored within this storage rib 11. This magnetic piece 10 may be stored in all storage ribs 11, or may be stored only in necessary storage ribs 11. The magnetic piece 10 is finally magnetized to correct misconvergence.

FIG. 4 shows the state in which the magnetization is being performed. That is, any picture tube 1 and any deflection yoke 9 are combined, the resulting misconvergence on the phosphor screen 3 is detected by a sensor (not shown), and the misconvergence on the phosphor screen 3 is detected at eight locations provided on the deflection yoke 9. Calculate with a computer or the like, or determine based on experience which location and how much magnetized magnetic piece 10 is required in which location of the storage rib 11, and use the magnetization head 12 to externally The magnetic piece 10 is more directly or indirectly magnetized. According to such a method, there is no need to repeatedly attach the magnetic piece 10 by trial and error, and optimal convergence can be achieved in an extremely short time. In addition, in the conventional method, the magnetic pieces 10 are stuck at random, which has the disadvantage of spoiling the appearance, but by providing storage ribs 11 for the magnetic pieces 10 at predetermined locations as in the above embodiment, this can be improved. It also eliminates the drawbacks.

In the above embodiment, an example was shown in which the storage rib 11 was provided on the opening side of the deflection yoke 9, but the storage rib 11
1 may be provided on the electron gun 5 side, or may be provided approximately in the middle of the deflection yoke 9, as long as it is on the phosphor screen side of the deflection magnetic field from the deflection yoke 9. Further, in the above embodiment, the storage ribs 11 are arranged at equal intervals, but the storage ribs 11 are formed continuously, and the magnetic pieces 10
may be arranged over the entire circumference of the deflection yoke 9.

Note that when magnetizing the magnetic piece 10, if strong local magnetization is performed, it may bring about undesirable results such as raster distortion and deterioration of focusing characteristics of the electron beam, so the amount of magnetization should be small and gradually carried out. is desirable.

As described above, according to the present invention, necessary magnetic pieces are externally magnetized with a necessary strength from among a plurality of pre-arranged magnetic pieces, depending on the degree of misconvergence and the location where it occurs. Therefore, convergence adjustment can be performed extremely efficiently and with high precision, and as a result, it is possible to realize a high-quality picture tube not only at the B1 level but also at the B2 level. Moreover, in order to finely perform such misconvergence correction, it is desirable to increase the number of magnetic pieces.
At this time, if many of the magnetic pieces are left exposed, the appearance will be impaired. In this regard, in the present invention, the storage rib is provided and the magnetic piece is stored therein, so that the appearance is not spoiled.
In addition, in the conventional method, there was a limit where correction was impossible due to the combination of the picture tube and the deflection yoke, but with this invention, the range that can be corrected can be expanded, so the yield of adjustment can be improved. can be improved.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing the configuration of a conventional color picture tube, FIG. 2A is a side view showing a conventional deflection yoke, FIG. 2B is a rear view of the same, and FIG. FIG. 3B is a side view showing an embodiment of the deflection yoke used, FIG. 3B is a rear view thereof, and FIG. 4 is a side view showing a magnetized state. 1... Picture tube, 2... Panel, 3... Fluorescent screen,
4... Funnel, 5... Electron gun, 6... Net, 8... Cone section, 9... Deflection yoke, 10...
...Magnetic piece, 12... Magnetizing head. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 A panel with a phosphor screen formed on its inner surface, a net with a built-in electron gun that emits an electron beam that makes the phosphor screen emit light, a funnel connecting the panel and the net, and an outer cone of the funnel. A method for correcting misconvergence in a picture tube equipped with a fitted deflection yoke, wherein the picture tube is housed in a storage rib provided along the outer periphery of the deflection yoke on the phosphor screen side of the deflection magnetic field by the deflection yoke. A plurality of unmagnetized magnetic pieces are arranged in the circumferential direction, and the necessary magnetic pieces are selected from among the plurality of magnetic pieces according to the degree of misconvergence on the phosphor screen and the location where the misconvergence occurs. A misconvergence correction method for a picture tube, which is characterized by externally magnetizing a picture tube with a certain strength.