JPH09306379A - Cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify an adjustment of color purity together with an adjustment of convergence, absorb dispersion in a manufacturing process, improve a quality, and enhance manufacturing efficiency by constituting a ring-shaped magnet to correct a side beam component so as to be longitudinally movable. SOLUTION: A bipolar magnet 2, a quadrupole magnet 3 and a hexapolar magnet 4 are fitted around and arranged in a neck part 12 of a cathode-ray tube as an orbit adjusting means of electron beams. Among these, the convergence adjusting quadrupole magnet 3 is composed of two sheets, and is longitudinally moved between the bipolar magnet 2 and the hexapolar magnet 4, and a side beam component of three electron beams of G, R and B is symmetrically corrected to a central beam, and is fixed after correcting a position where side beams strike on a phosphor. Therefore, dislocation between the phosphor and the beams by dispersion caused by a manufacturing process of the cathode- ray tube and an electron gun can be absorbed, and uniformity of color purity of the cathode-ray tube is obtained, and a yeild is improved, and cost can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube having a correction magnet capable of adjusting electron beam mismatch as well as electron beam convergence.

[0002]

2. Description of the Related Art In a color cathode ray tube (CRT), for example, as shown in FIG. 4, a vacuum container is composed of a panel 10, a funnel 11 and a neck tube 12, and the panel 10 and the funnel 11 are made of a frit glass 13. It is joined. On the inner surface of the panel 10 is formed a phosphor screen 21 coated with phosphors for emitting blue, green and red light.
1, a color selection mask 22 is arranged in proximity to 1. The electron beam from the electron gun 30 housed in the neck 12 is deflected in a predetermined direction by the deflection yoke 31, and the color selection mask 2
After passing through 2, it reaches the phosphor screen 21 formed on the inner surface of the panel 10 and excites a predetermined phosphor to emit light.

An electron gun 30 is attached to the neck portion 12 of the cathode ray tube.
A ring-shaped correction magnet is arranged as a means for adjusting the orbits of the three emitted R, G, and B electron beams. This correction magnet is normally a two-pole magnet 32,
The 4-pole magnet 33 and the 6-pole magnet 34 are fixed at predetermined positions on the neck portion 12 in this order. An enlarged view of this neck is shown in FIG.
Shown in These ring magnets 32, 33, 34 are
Each of them is composed of two sheets, and is fitted onto the neck portion 12 on the rear side (electron gun side) of the deflection yoke 31 and fixed by a fixing metal fitting 36.

The bipolar magnet 32 is a purity magnet for adjusting color purity. The 4-pole magnet 33 and the 6-pole magnet 34 are convergence adjustment magnets, and the 6-pole magnet 34 is used to correct the asymmetric component of the three electron beams.
The quadrupole magnet 33 is used to correct the symmetric misconvergence component of the position of the side beam with respect to the central beam, as shown in FIGS. 6 (A) and 6 (B).

In the correction magnet composed of these two sheets, the direction and strength of the magnetic field are changed by changing the opening angle of the two sheets or rotating the two sheets at the same time. These correction magnets are fixed so as not to rotate after adjusting the electron beam of the cathode ray tube.

[0006]

However, conventionally,
The above-mentioned correction magnet cannot absorb the deviation (mismatch) between the phosphor of the cathode ray tube and the electron beam, which is caused by the variation caused in the cathode ray tube manufacturing process and the electron gun manufacturing process. The three electron beams have their respective phosphors hit, and if the beams do not hit the predetermined phosphors correctly, the color purity decreases. With the recent finer pitch, the product specifications are becoming stricter, and if such a mismatch cannot be absorbed, the yield will be reduced due to poor color purity. Therefore, there is a demand for a cathode ray tube that can easily absorb a mismatch by adjustment.

The present invention has been made in view of the above demands, and it is an object of the present invention to provide a cathode ray tube which can easily adjust the color purity as well as the convergence and can absorb the variation caused in the manufacturing process. To aim.

[0008]

In order to achieve the above object, the present invention has a side beam component with respect to a central beam among three electron beams which are arranged at a neck portion of a cathode ray tube and emitted from an electron gun. Provided is a cathode ray tube having a pair of ring-shaped symmetrical correction magnets for symmetrically correcting with respect to each other, wherein the ring-shaped symmetrical correction magnets can be moved and fixed in the front-rear direction of the cathode-ray tube. .

The cathode ray tube of the present invention comprises a compensating magnet called a quadrupole magnet (a pair of three electron beams emitted from the electron gun of the cathode ray tube, which is a pair of symmetrically compensating side beam components with respect to the central beam. The ring-shaped symmetry correction magnet) can be moved and fixed in the front-back direction of the cathode ray tube.

This quadrupole magnet has hitherto been used for converging convergence, and has not been used for the purpose of just landing the orbits of the phosphor and the electron beam of the cathode ray tube. When the position of the 4-pole magnet is changed in the front-back direction of the cathode ray tube (the tube surface side is the front and the electron gun side is the rear),
The incident angle of the side beam fluctuates, for example, 1 cm ahead
When the quadrupole magnet is moved, the position where the side beam hits the phosphor is moved away from the central beam in both directions by about 4 μm.
This makes it possible to correct the beam mismatch and adjust the color purity by just landing the electron beam on the phosphor. Since this 4-pole magnet is a correction magnet that can adjust the convergence, it has the function of adjusting the convergence by rotating it. In addition to this, by changing the mounting position in the front-back direction, the color purity can be improved. Can be adjusted and a mismatch correction function, which has not been used in the past, is added, so that the mismatch generated in the manufacturing process can be easily absorbed.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiments of the present invention will be specifically described below, but the present invention is not limited to the following embodiments. The overall structure of the cathode ray tube of the present invention is the same as that of the cathode ray tube shown in FIG. 4, except for the structure of the four-pole magnet in the neck portion. That is, the panel 10, the funnel 11, and the neck tube 12 constitute a vacuum container, and the panel 10 and the funnel 11 are joined by the frit glass 13. On the inner surface of the panel 10, a phosphor screen 21 coated with phosphors for emitting blue, green and red light is formed, and a color selection mask 22 is arranged close to the phosphor screen 21. The electron beam from the electron gun 30 housed in the neck 12 is deflected in a predetermined direction by the deflection yoke 31, passes through the color selection mask 22, reaches the fluorescent screen 21 formed on the inner surface of the panel 10, and receives a predetermined fluorescent light. The body is excited to emit light.

An electron gun 30 is attached to the neck portion 12 of the cathode ray tube.
Three types of ring-shaped correction magnets are arranged as means for adjusting the orbits of the three R, G, and B electron beams emitted. This compensating magnet includes a two-pole magnet 2 from the tube surface side,
The 4-pole magnet 3 and the 6-pole magnet 4 are fixed to the neck portion 12 at predetermined positions in this order. An enlarged view of this neck portion is shown in FIG. These ring-shaped magnets 2, 3 and 4 are respectively 2
It is composed of a single sheet, and is fitted onto the neck portion 12 between the deflection yoke 31 and the electron gun 30 which is partially shown in the drawing and is composed of grids G3, G4A, G4C, G4B, and G5B. These correction magnets are rotatable before shipment adjustment, and the direction and strength of the magnetic field can be changed by changing the opening angle of the two sheets or rotating the two sheets at the same time. These correction magnets are fixed so as not to move after adjusting the electron beam of the cathode ray tube. 2-pole magnet 2
Is a purity magnet that adjusts color purity. The 4-pole magnet 3 and the 6-pole magnet 4 are convergence adjustment magnets,
The sextupole magnet 4 is used to correct the asymmetric component of the three electron beams.

In the cathode ray tube of the present invention, the distance between the two-pole magnet and the six-pole magnet is set larger than usual, and two 4-pole magnets are arranged between the two-pole magnet and the six-pole magnet before adjustment. It is configured such that two sheets can be moved back and forth while being stacked and can be fixed at the same time. Further, each of the quadrupole magnets composed of two pieces can rotate, and the convergence can be adjusted as shown in FIG. The movable range of the 4-strong magnet is not particularly limited and can be increased within a range permitted by the relationship with other members in the neck portion of the cathode ray tube, but is ± 20 mm with respect to the position of the conventional 4-pole magnet.
It is preferable to set the degree.

Next, the principle of correcting a mismatch by moving the quadrupole magnet back and forth in this way will be described with reference to FIG. For example, when the quadrupole magnet is at the position shown in FIG. 3, among the three electron beams R, G, and B, the phosphors 21R to be applied through the color selection electrodes of the side beams of R and B, respectively. As shown by the solid line in the drawing, the position corresponding to 21B hits a biased position on the side of the central beam, causing mislanding, and the color purity is lowered.

When the mounting position of the quadrupole magnet is changed from to the position on the tube surface side, as shown by the broken line in the figure, the position of the side beam that the phosphor hits is away from the central beam in both directions. The beam can be corrected so that it strikes the center of the phosphor, and the color purity can be improved. Conversely, if the position of the side beam that hits the phosphor is away from the central beam, this time, by changing the mounting position of the 4-pole magnet to the rear side,
The position where the side beam hits the phosphor can be shifted to the center side, and mislanding can be corrected to improve color purity. According to the experiment, the 4-pole magnet is 10 m
It has been confirmed that the position of the side beam hitting the phosphor can be moved by about 4 μm by changing the mounting position. Therefore, if the mounting position of the 4-pole magnet can be moved back and forth by ± 20 mm, a mismatch correction of ± 8 μm can be performed.

As shown in FIG. 6, the quadrupole magnet symmetrically corrects the side beam component of the three electron beams with respect to the center beam, and the two magnets are rotated to rotate the same. As shown in FIG. (A), the side beams are moved horizontally in opposite directions to each other with respect to the center beam, or as shown in FIG. Can be adjusted. Also, the amount of movement can be changed by changing the opening angle of the two magnets.

When the cathode ray tube is adjusted, for example, the quadrupole magnet is rotated to adjust the convergence, and when a mismatch is found, the mounting position of the quadrupole magnet is changed to change the incident angle of the beam. Correction, then tighten the screw, apply lacquer paint, etc.
The position of the pole magnet can be fixed so that it does not move before shipment.

As described above, the cathode ray tube of the present invention adopts the mechanism for changing the mounting position of the quadrupole magnet, so that in addition to the convergence correction function of the quadrupole magnet, the correction of the position where the side beam hits the phosphor is performed. Therefore, it is possible to absorb the deviation (mismatch) between the phosphor of the cathode ray tube and the electron beam, which is caused by the variation generated in the cathode ray tube manufacturing process and the electron gun manufacturing process. Therefore, it is possible to improve the color purity uniformity of the cathode ray tube, improve the quality thereof, and reduce the color purity failure due to the above variation. Further, even if the product standard of the cathode ray tube regarding the color purity is relaxed, it can be absorbed, so that the yield can be improved and the cost can be reduced.

In the above embodiment, the quadrupole magnet 3a having a two-sheet structure,
Although the example of moving in the state where 3b is overlapped has been described, two 4
The polar magnets 3a and 3b can be configured to be movable and fixed independently of each other. Vs increases as the distance between the 4-pole magnets increases.
Since the correction sensitivities of t (vertical static misconvergence) and XBV (bow-shaped misconvergence on the X-axis) increase, the correction ranges can be expanded by arranging them separately.

The present invention can be applied to both the shadow mask system and the aperture grill system. Further, in the above-described embodiment, an example in which a 2-pole magnet and a 6-pole magnet are arranged is shown, but these correction magnets are not essential, and other configurations can be variously modified without departing from the gist of the present invention. ..

[0021]

According to the present invention, since the four-pole magnet is movable between the cathode lines, it is possible to easily adjust the color purity as well as the convergence, and it is possible to absorb the variation caused in the manufacturing process. it can.

[Brief description of drawings]

FIG. 1 is a plan view showing a whole between cathode lines of the present invention having a partially cutaway cross section.

FIG. 2 is a plan view showing a neck portion between cathode lines according to the present invention.

FIG. 3 is a conceptual diagram showing that mismatch can be corrected by changing the position of a quadrupole magnet.

FIG. 4 is a plan view having a partially cut-away cross section showing the entire space between conventional cathode lines.

FIG. 5 is a side view showing a structure of a conventional neck portion between cathode lines.

FIG. 6 is a conceptual diagram illustrating the operation of a quadrupole magnet.

[Explanation of symbols]

2 ... 2-pole magnet, 3 ... 4-pole magnet, 4 ... 6-pole magnet, 10 ... Panel, 12 ... Neck part, 21 ... Phosphor screen, 22 ... Color selection electrode, 30 ... Electron gun, 31 ... Deflection yoke.

Claims (3)

[Claims] 1. A pair of ring-shaped symmetrical correction magnets which are arranged at a neck portion of a cathode ray tube and symmetrically correct a side beam component of three electron beams emitted from an electron gun with respect to a central beam. In the cathode ray tube, the ring-shaped symmetrical correction magnet is moved in the front-back direction of the cathode ray tube,
A cathode ray tube characterized in that it can be fixed. 2. A cathode ray tube according to claim 1, wherein a purity magnet and a sextupole magnet are arranged in front of and behind the ring-shaped symmetrical correction magnet. 3. The cathode ray tube according to claim 1, wherein each of the pair of ring-shaped symmetrical correction magnets is arranged so as to be spaced apart from each other in the front-rear direction of the cathode ray tube.