JPS61220252A - Convergence device - Google Patents

Abstract

PURPOSE:To reduce the color shift considerably by employing Fe-Cr-Co system alloy having limited dimension and the temperature coefficient lower than specific level for the tetra-pole magnet in the convergence magnets in inline color cathode ray tube. CONSTITUTION:The convergence apparatus 5 for focusing the electron beam from an electron gun in an inline color cathode ray tube to single point at the screen section is formed with tetra-pole magnets 6a, 6b comprised of a set of two sheets, hexa-pole magnets 7a, 7b and di-pole magnets 8a, 8b. Here, the tetra-pole magnets 6a, 6b are made of Fe-Cr-Co system alloy with the outer diameter and the length respectively within 1.5-4.0mm and 2.0-6.0mm while the absolute level of the temperature coefficient lower than 0.01%/ deg.C. Consequently, when reducing the variation of magnetic force of tetra-pole magnets 6a, 6b which will contribute considerably to the color shift caused on the temperature rise, high quality picture image can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a static convergence device for converging electron beams in a color cathode ray tube having a plurality of electron guns.

Conventional technology A static convergence device (hereinafter abbreviated as STC) used in in-line type calab or cathode ray tubes (hereinafter abbreviated as CRT) is a static convergence device (hereinafter abbreviated as STC) that converges three electrons emitted from three electron guns attached to the neck of the cathode ray tube. It has the function of focusing the electron beam to one point on the CRT screen section, and is equipped with ring-shaped magnets each having four and six magnetic poles, each consisting of a pair of two magnets. Also S
A set of two ring magnets called "Bulity" are attached to the TC for adjusting color purity.

(For example, Special Publication No. 54-12020, No. 55-3065
(See No. 9) Figure 1 shows the schematic structure of a color cathode ray tube.

In the figure, the CRT is composed of a screen section 1, a funnel section 2, a neck section 3, and a deflection yoke 4.5TC5.

FIG. 2 shows a detailed diagram of 5TC5. In the same figure, 6a
16b is a 4-pole magnet, 7a17b is a 6-pole magnet, and 8a.

8b is a two-pole magnet, and each magnet has a protrusion 13 to facilitate rotational adjustment. Each set of two magnets is partitioned with a spacer 9 to prevent other ring magnets from rotating, and after the STC is adjusted, they are fixed to the cylindrical member 11 with a retaining ring 10. Further, 12 is a metal clamp for fixing the STC to the CRT neck.

Figures 3 <a> to (C) are diagrams schematically representing the action of each ring-shaped magnet, which is composed of a set of two magnets, on each electron beam. Beam blue (B)
, green (G), and red (R).

FIG. 3(a) is a diagram showing the moving direction of each beam by the 411 magnet. Due to the magnetic flux generated from the quadrupole magnets, the side beams (B, R>) receive forces in opposite directions, and by rotating and adjusting the pair of quadrupole magnets, both beams can be moved closer to the center beam (G). By doing so, both beams (8,R) can be focused at one point.That is, the quadrupole magnet is STC
This function has the greatest effect on color misregistration, which is the most important issue. At this time, it is desirable that the center beam (G) has an opening that is not affected by magnetic flux and does not move.

FIG. M3 (b) is a diagram showing the moving direction of each beam by the hexapole magnet. Due to the magnetic flux of this six-pole magnet, the side beams (8) and (R) receive force in the same direction, and the two six-pole magnets
By adjusting the rotation of the pole magnet, the side beams (B) and (R), which have already been focused at one point by the quadrupole magnet, are focused into the center beam (G), that is, the three electron beams are combined into one.
It can be focused on a point. At this time as well, it is desirable that the center beam (G) does not move.

FIG. 3(C) is a diagram showing the moving direction of each beam by the two-pole magnet. Due to the magnetic flux of this dipole magnet, all three beams (B, G, R) receive a force acting in the same direction, and color purity is improved by rotating the two dipole magnets. It can be adjusted.

Next, since the purpose of using a set of two of the four-pole, six-pole, and σ2-pole magnets can be considered to be the same for each magnet, a detailed explanation will be given focusing on the four-pole magnet.

Figure 4(a) shows two facing 8i! & This shows a state in which the poles overlap, but in this state, it appears that the magnetic flux is twice as much as when there is only one side beam (B).

R), the movement distance is doubled, that is, the maximum beam movement amount is obtained. In this case, the side beams move toward the center beam.

Although Fig. 4(b) does not show the state in which the same magnetic poles overlap as in Fig. 4(a), comparing it with Fig. 4(a) shows that the magnetic pole position relative to the electron beam position is Since these are different, the side beam (B) moves downward in the drawing, and the side beam (R) moves upward.

Figure 4 <C,) shows a state in which two opposing magnetic poles of different polarity overlap, and in this state, the magnetic flux generated from each magnetic pole acts on each beam so as to cancel each other out relatively. Therefore, no movement of the three beams occurs.

Figure 4 (d) shows a state in which two opposing magnetic poles of the same polarity (or different polarity) are shifted by 45 degrees from each other. In this state, the side beam (B) The beam (R) moves to the upper left, but the magnetic flux generated from each magnetic pole is partially canceled out, so the moving distance is as shown in Figure 4 (a).
), (1) will be less than ).

As mentioned above, by appropriately adjusting the rotation of a pair of 4-pole, 6-pole, and 2-pole magnets, the three electron beams emitted from the three electron guns are focused on one point on the screen. It is possible to produce vivid and colorful images.

Problems to be solved by the invention However, the STC magnets used in conventional CRTs are
Generally, so-called plastic magnets made by bonding ferrite magnetic powder with resin are mainstream, and their temperature coefficient is approximately -0.2.
%/°C, the color shift caused by the temperature rise is large, and it is currently being confirmed that it is unsuitable for color displays, etc., which have been rapidly growing in recent years.

The present invention improves the drawbacks of the above-mentioned prior art, and has extremely little change in magnetic force due to temperature changes (very little color shift).
The purpose is to provide a convergence device.

Means for Solving the Problems The convergence device of the present invention converges an electron beam emitted from an electron gun of an in-line color cathode ray tube having a plurality of electron guns into one electron beam at a screen portion of the color cathode ray tube.
A convergence device for focusing on a point has 4-pole and 6-pole static magnets, each consisting of a set of two magnets, and the magnetic pole portions of the 4-pole static magnets have a temperature coefficient of positive or negative depending on the size. It is a magnet that changes negatively, and its dimensions are an outer diameter of φ 1.5 to 4.011.
1゜艮za2,0/6. Fe -Or -C where the absolute value of the temperature coefficient defined as Oa+Ill is less than or equal to O,oi%/°C
It is characterized by the use of o-based alloy magnets.

Structure of the Invention The present invention focuses three electron beams emitted from an electron gun located in the neck of a CRT onto one point on a screen by rotating and adjusting four-pole and six-pole static magnets. However, of the 4-pole and 6-pole magnets, the 4-pole magnet is more involved in color shift caused by temperature rise, so the material of the 4-pole magnet has been changed from the conventional Ba ferrite plastic magnet to a material with a higher temperature coefficient. It is intended to replace the Fe-Cr-Co alloy magnet, which has been improved to be extremely small.

As is well known, the temperature coefficient (hereinafter abbreviated as α) of a Fe-Cr-Co alloy magnet varies greatly depending on the magnet size ratio.
The permeance coefficient (hereinafter abbreviated as Pc) is infinite, that is, B
At point r, it has a negative α, but as the Pc becomes lower, the slope of the negative α becomes gentler.Assuming that the material and demagnetization characteristics are the same, it has the unique property that the sign of α reverses at a certain pc. have.

The present invention takes advantage of the unique properties of Fe-Cr-GO alloy magnets, controls the dimensions of the magnet within a specific range, and produces magnets with extremely low magnetic force (very small α) against temperature changes. It was used as a magnet.

Specific dimensions and shapes of alloy magnets include outer diameters of 1.5 to 4.
011φ and the length is preferably in the range of 2.0 to 6.0-1. This is because if the outer diameter is less than 1.5a+mφ and the length is less than 2,011mm, it is difficult to obtain sufficient magnetic force as a convergence magnet, and the absolute value of the temperature coefficient is likely to exceed o, oos%. This is because color shift caused by temperature rise becomes a problem.

In addition, the outer diameter exceeds 4.0iiφ and the length is 6.0+e.
If it exceeds m, when assembled as an STC, the STC itself becomes large and has the disadvantage of being impractical.

For the above reasons, the outer diameter of the magnet is 1.5 to 4.011.
It is necessary to have a diameter of 1 mφ and a length of 2.0 to 6.01111 mm.

Furthermore, in the present invention, more preferable results are obtained when the ratio of magnet length/magnet diameter is in the range of 1.4 to 2.7.

In the above explanation, the case where a cylindrical magnet is used is explained, but the present invention is not limited to this, and as long as the cross-sectional area of the magnet is in the range of 1.7u+2 to 12.61+m2, a rectangular parallelepiped magnet is used. You can also use it as

In addition, the specific temperature coefficient is 0.01%/
It is preferably 0.005%/°C or less, more preferably 0.005%/°C or less. The advantages of setting the temperature coefficient to 0.01% or less in absolute value are as follows.

The temperature coefficient of normal ferrite magnets is approximately -0.2%/℃
If the temperature change (ΔT) is 80℃, the temperature change will be 16 compared to the initial value.
% magnetic force decreases. Assuming that the side beam is relatively corrected by 4+u in STC, theoretically 0.64a
lllll beam deviation will occur, and this is considered unsuitable for color displays and the like. On the other hand, if the temperature coefficient is set to 0.01% or less in absolute value, the beam deviation can be significantly reduced. In particular, if it is set to 0.01% or less, the beam deviation will be 0.016ml or less under the same conditions, which is due to temperature rise. The color shift caused by this is almost negligible, and it is thought that it can be used satisfactorily for color displays.

Example Examples of the present invention will be described below.

Example 1 Fe having a shape with an outer diameter of 2.5iiφ and a length of 4.011
-, (:, r-co alloy flyite (Br-8200G%H
c -4600e) 15 were embedded in a plastic ring 14 with an outer diameter of 46+amφ, an inner diameter of 34IIllφ, and a thickness of 2.7mm, as shown in Figure 5, at 90° intervals, and magnetized as shown in the figure -4゛. I made two pieces.

The 6-pole and 2-pole magnets are 13a ferrite plastic magnets (Hitachi 1117KPM-2A) with an outer diameter of 46+a+gφ, an inner diameter of 34mmφ, and a wall thickness of 1.4mm.
After manufacturing two ring-shaped magnets of No. 1111, they were each magnetized with six poles and two poles so that the magnetic pole opening angles were equal.

4.6. For each two-pole magnet, a projection 13 is provided on a part of the ring as shown in Figure 5 to allow smooth rotation for beam adjustment, and the CRT is assembled as an STC as shown in Figure 2. After installing the beam into the system, the amount of beam movement was measured. (The test CRT used was one in which the distance between the side beams (B, R) when STC was not used was 4.211 at the center of the screen.) As a result, by rotating the quadrupole magnet, each side beam The maximum travel distance was 8.401 m, and when the three beams were adjusted to one point at room temperature, the Fe-Cr-Co alloy magnet used in this example was sufficiently functional as an STC magnet. This was confirmed.

Additionally, the ambient temperature of the STC was experimentally raised by 80°C above room temperature.
When the distance between the side beams was stabilized, the distance between the side beams was measured again.
), and it was confirmed that almost no beam movement occurred and no C was observed.

Furthermore, the amount of magnetic flux of the quadrupole magnet used in this example was measured and found to be 97.6M x.

Example 2 The outer diameter was 2.5 mm and the width was 4.5 mm as used in Example 1. l”e-0r-Co alloy magnet (Br
= 8300G, Ha -46000e) were heat-magnetized at various temperatures and embedded in a plastic ring having the same shape as in Example 1 to produce a quadrupole magnet. The same measurements were performed using the six-pole and two-pole magnets and CRT used in Example 1.

As a result, the initial maximum movement amount of each side beam is 5. l
The magnetic flux m of the magnet that showed 0IDI was 59.8M x, so the magnetic flux was 160. OMX or more is Fe in the present invention
- This was the target value for a Cr-Co alloy magnet.

Example 3 24 types of Fe having wire diameters and lengths shown in Table 1
-0r-Co alloy magnet (Br = 8,200~8.
350G, HC = 440-4650e) was manufactured and the temperature coefficient and magnetic flux amount were measured. The measurement results are also shown in Table 1. The temperature coefficient was determined by measuring reversible temperature characteristics between 0 and 120° C. using a magnet with a sufficient magnetic field and using a post-magnetic vibrating magnetometer. The values shown in Table 1 are the average reversible temperature coefficients between the measured temperatures, and the absolute values of the temperature coefficients in Table 1 are targeted. Samples within , oos% are marked with 0.

In addition, the amount of magnetic flux was measured using a magnetometer after sufficiently magnetizing the magnet, and from the results of Example 2, the amount of magnetic flux was 60.0M.
Samples with a grade of X or higher are marked with an O mark.

Absolute value of temperature coefficient is 0.005% or less and magnetic flux amount is 60
．． A mark ◎ was written in the overall evaluation column for samples that satisfied both characteristics of 07yl x or higher. As is clear from Table 1,
10 out of 24 samples were able to satisfy the target value.

Table 1 Example 4 Ten samples of Fe-Cr-Go alloy magnets whose temperature coefficient and magnetic flux values satisfied the target values in Example 3 were used as shown in Fig. 5, with an outer diameter of 48 mm+φ and an inner diameter of 34 III
Four magnets were embedded in a plastic ring 14 having a diameter of 1φ and a thickness of 4.2o+m at an angle of 90'', and two magnets were manufactured for each magnet with magnetization as shown in the figure.

The same measurements as in Example 1 were carried out using the 6-pole and 2-pole magnets and CRT used in the example.

As a result, the initial maximum movement amount of each side beam was 5.1011 for No. 2 sample to No. 1 sample as shown in Table 2.
The diameter of the 0 sample was 15.80 mm, and by adjusting the 4-pole and 6-pole magnets, it was possible to converge the three beams to one point.

In addition, after raising the ambient humidity of the STC by 80 degrees Celsius above room temperature, the distance between the side beams was 0.051 for all Nos. 1 to 10 after the stability was lost.
It was found that there was extremely little color shift of m or less.

Table 2 As described in detail of the invention, the present invention has improved the temperature coefficient of the quadrupole magnet from the conventional ferrite plastic magnet among the static convergence magnets that focus the electron beam in an in-line color cathode ray tube having a plurality of electron guns. By controlling the magnet dimensions within a specific range, the absolute value of the temperature coefficient can be reduced to o, oi%/°C.
By using the magnet described below, it is possible to provide a high-quality static convergence device for a color cathode ray tube with extremely little color shift.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a color cathode ray tube, Figure 2 is a detailed diagram of static convergence, Figure 3 is a diagram of the influence of the 4.6.2-pole magnet on the electron beam, and Figure 4 is the quadrupole magnet 2.
FIG. 5 is a diagram illustrating an example of the quadrupole magnet using a metal magnet according to the present invention. 1 Niskurin part, 3: Neck part, 4: Deflection yoke, 5
:STC, 6a, 6b: 4-pole magnet, 7a, 7b
Two dipole magnets, Figure 1 kl! ? 2 Figure 3 Figure (a) (b)
(c) Figure 5/? Figure 4

Claims (1)

[Claims] 1. In a convergence device that focuses the electron beam emitted from the electron gun of an in-line color cathode ray tube having multiple electron guns to one point on the screen portion of the color cathode ray tube, each convergence device is composed of a set of two 4 The magnetic pole part of the 4-pole or 6-pole static magnet has a magnetic pole and a 6-pole static magnet, and is an Fe-Cr-Co alloy magnet whose temperature coefficient changes to be positive or negative depending on the size. and its dimensions are outer diameter φ1.5~4.0m.
Fe-Cr-Co whose absolute value of temperature coefficient is 0.01%/℃ or less by setting the length to 2.0 to 6.0 ml.
A convergence device characterized by using a alloy magnet.