KR100300410B1 - Apparatus for compensating convergence in a color cathod ray tube - Google Patents

Abstract

PURPOSE: The present invention relates to a device for compensating convergence of color CRTs, and in particular, to minimize convergence drift variation of R and B electron beams due to thermal expansion of first and second grid electrodes of electron guns and charge components of CRTs, thereby improving convergence characteristics. .

Composition: The second grid electrode 24 of the electron gun 20 in a color CRT tube which realizes an image by collecting the electron beam emitted from the electron gun at a point on the screen using a convergence purity magnet and scanning it on the screen by a deflection yoke. ) And an auxiliary magnet ring 52 magnetized to at least four poles on an outer circumference of the neck N between the deflection yoke and the deflection yoke 60. The auxiliary magnet ring forms a groove 48a at the front of the holder 48 so as to directly receive the heat of the neck N, and the projections 48b and 48c and the engaging jaw (around the groove 48a). 48d) to be fixed by fitting engagement.

Effect: The auxiliary magnet ring compensates for convergence drift due to thermal expansion of the first grid electrode at the beginning of operation, and deteriorates to -0.2% / ° C or -0.02% / ° C after the neck reaches a certain temperature. It is possible to compensate for convergence drift due to thermal expansion and charge components of the two grid electrodes, and as a result, to minimize the amount of change in the overall convergence drift, thereby improving image quality.

Description

Apparatus for compensating convergence in a color cathod ray tube}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a convergence compensation device of a color CRT that can improve convergence characteristics by compensating convergence drift of R and B electron beams occurring on a screen.

The color CRT accelerates the electrons emitted from the electron gun to a high voltage and lands them on the phosphor, thereby realizing an image by excitation emission of the phosphor.

As shown in FIG. 7, the color CRT tube emits an electron beam from an in-line electron gun 2 installed in the neck N, and converges the purity beam (hereinafter referred to as CPM) to collect the electron beam at one point on the screen S. (4), the deflection yoke (6) is employed to scan the electron beam on the screen, and the electron beam passing through the shadow mask (8) of the corresponding R, G, B on the screen (S) Landing on the phosphor results in the desired image.

Here, the CPM (4) is a pair of magnet rings magnetized into two poles, four poles and six poles are installed in pairs using holders and spacers fixed to the neck (N), respectively. Convergence adjustment by pole and 6 pole magnet ring is made.

More specifically, the adjustment work through the CPM 4 allows the center G electron beam to be positioned at the center using a two-pole magnet ring, and the R and B electron beams coincide by using a four-pole magnet ring. This is accomplished by matching R, B electron beams and G electron beams using polar magnet rings. In this case, the distance between the R and B electron beams (Outer Convergence Variance (OCV) is adjusted by the 4-pole magnet ring, and the distance from the center of the R and B electron beams to the G electron beam (Center Convergence Variance (CCV)) is adjusted by the 6-pole magnet ring. Will be.

However, the color CRT realized as described above is accompanied with various factors that generate convergence drift when operating for a certain time by switching on.

For example, the electron gun 2 of the color CRT is thermally deformed by the influence of the heating temperature and the external temperature of the heater, which is the first grid electrode (or G1 electrode) close to the heater of the cathode 2a as shown in FIG. 8. This causes thermal expansion of (2b) and the second grid electrode (or G2 electrode) 2c, resulting in a thermal drift of convergence. The heater of the cathode 2a is usually heated to 780 ° C, so that the first grid electrode 2b is raised to 400 ° C and the second grid electrode 2c is heated to 150 to 200 ° C. (2b) is thermal expansion in the direction of the arrow at the beginning of the operation of the CRT to cause the initial state of convergence (C) to drift in the '+' direction (the electron gun side relative to the screen) (C1), and then similarly in the direction of the arrow. Under the influence of the second grid electrode 2c, the convergence is caused to drift in the '-' direction (the opposite side of the electron gun relative to the screen) C2.

As a result, the conventional color CRT is drifted to a maximum of +0.05 mm under the influence of the first grid electrode C1 up to approximately 10 to 15 minutes of operation, as shown in FIG. Under the influence of the grid electrode (C2), it drifts to a maximum of -0.15mm.

In addition, the conventional color CRT receives the + charge component (CG) generated at the end of the neck (N) approximately 10 minutes after the operation, which is due to the concentration of foreign matter remaining inside the bulb. This results in a charge drift that changes the convergence further in the '-' direction (CG) to drift up to -0.22 mm.

In order to compensate for this convergence drift, Korean Utility Model Publication No. 96-6527 discloses that the magnetic poles P _N and P _S are magnetized by forming spacers in the CPM with resin materials, thereby making it possible to artificially adjust OCV and CCV. A "convergence magnet assembly for cathode ray tubes with a dummy pole added" is disclosed.

However, the above-mentioned convergence magnet assembly has a problem that the effect is not only small but also does not substantially reduce the change amount C1 + C2 + CG of the overall convergence drift.

In order to solve the problems of the prior art described above, the present invention changes the convergence drift in the '-' direction at the beginning of the operation of the color CRT, and reverses the convergence drift from the point when the neck reaches a certain temperature. The present invention aims to provide a convergence compensation device for a color CRT that changes the amount of drift change in the + 'direction to improve the convergence characteristics of the R and B electron beams generated on the screen.

To this end, the present invention collects the electron beam emitted from the electron gun installed in the neck at a point on the screen by using a convergence purity magnet, and is scanned again on the screen by using a deflection yoke. An auxiliary magnet ring magnetized to at least four poles and having an opening is installed around the neck between the second grid electrode and the deflection yoke, and is configured to be fixed by projections and locking jaws formed in the holder of the convergence purity magnet.

The auxiliary magnet ring may be made of a ferrite material in which the magnetization amount changes at a rate of −0.2% / ° C., or may be made of an alnico material in which the magnetization amount is changed at a rate of −0.02% / ° C.

In particular, the auxiliary magnet ring is attached to the deflection yoke side of the holder constituting the convergence purity magnet, and magnetized with a polarity that causes the convergence of the R and B electron beams to be moved to the opposite side of the electron gun ('-' direction) with respect to the screen. To compensate for the drift change in the '+' direction due to thermal expansion of the first grid electrode. On the contrary, from the point where the neck reaches a certain temperature, the second grid is deteriorated by -0.2% / ° C or -0.02% / ° C magnetization. This is to compensate for convergence drift in the '-' direction due to thermal expansion and charge drift of the electrode. Therefore, according to the present invention, the amount of change in the overall convergence drift is reduced, whereby the effect of improving the convergence characteristics and the image quality can be obtained.

1 is a cross-sectional view showing the installation structure of the convergence compensation device according to the present invention.

Figure 2 is an exploded perspective view of the convergence compensation device according to the present invention.

3 is an exploded perspective view of a convergence compensator according to another embodiment of the present invention.

4 is a front configuration diagram of a convergence compensation device according to the present invention.

5 is an operational state diagram of the convergence compensation device according to the present invention.

6 is a view showing the amount of change in convergence drift according to the present invention.

Figure 7 is a cross-sectional view showing a typical color CRT.

8 is an operational state diagram showing a convergence drift according to the prior art.

9 is a view showing the amount of change in convergence drift according to the prior art.

<Description of Symbols for Main Parts of Drawings>

N-neck 20-gun

22-first grid electrode 24-second grid electrode

40-CPM 42,44,46-Magnet Ring

48-holder 48b-protrusion

52-secondary magnet ring 52a-hole

60-deflection yoke 60a-holder

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment for implementing this invention is demonstrated in detail based on an accompanying drawing.

Figure 1 shows the installation structure of the convergence compensation device according to the present invention, Figure 2 shows the configuration of the convergence compensation device according to the present invention.

As shown in the drawing, the convergence compensation device of the color CRT according to the present invention includes a CPM 40 that collects electron beams emitted from the electron gun 20 installed in the neck N at one point on the screen. In addition, the auxiliary magnet ring 52 having a distance of 0 to 2.0 mm from the outer circumferential surface of the neck N between the deflection yoke 60 for scanning the electron beam on the screen and the second grid electrode of the electron gun 20. It consists of the configuration installed.

The CPM 40 includes a holder 48 and a spacer 50 having three pairs of magnet rings 42, 44 and 46 including paired 2-poles, 4-poles, and 6-poles fixed to the neck N. It is a normal configuration to be supported and installed by use.

The auxiliary magnet ring 52, which is an object of the present invention, forms a groove 48a in front of the holder 48 so as to receive heat of the neck N directly, and a protrusion (a) around the groove 48a. 48b) and 48c and the locking step 48d are formed so that they may be fixed by fitting engagement. In this case, the auxiliary magnet ring 52 may first be inserted into and secured to the outer periphery 52a of the opening by the locking jaw 48d, and then may be fixed by pushing the hole 52b to be engaged with the protrusion 48b. In addition, when there is no hole 52b and the projection 48b, the auxiliary magnet ring 52 can be fixed by the frictional force of the outer peripheral surface and the projection 48c.

In addition, the auxiliary magnet ring 52 of the present invention, as shown in Figure 3, the end of the opening 52a can be inserted into the locking jaw (48d) to be fixed.

The auxiliary magnet ring 52 configured as described above may be installed at the rear of the CPM 40 or the rear of the deflection yoke 60, and the electron gun 20 if it is in direct contact with the neck N or spaced apart to have a predetermined space. It can be installed anywhere in the area | region L between the 2nd grid electrode 24 of () and the holder 60a of the deflection yoke 60. As shown in FIG.

The auxiliary magnet ring 52 is magnetized to at least four poles as shown in FIG. 4, and the convergence of the R and B electron beams is far from each other, and is opposite to the electron gun ('-' direction relative to FIG. 9) based on the screen. Since it is magnetized to the polarity to be moved, it is to actually move in the direction away ('-' direction) the linear distance (OCV) of the R, B electron beam on the screen (S) as shown in FIG. Accordingly, the auxiliary magnet ring 52 compensates the amount of drift change in the '+' direction due to thermal expansion of the first grid electrode 22 of the electron gun 20 so as to be reduced in the '−' direction at the initial operation.

In addition, the auxiliary magnet ring 52 according to the present invention is a ferrite material or -0.02% / in which magnetization deteriorates by a coefficient of heat change of -0.2% / 占 폚 on the contrary from the point when the neck N reaches a predetermined temperature. It is composed of an alnico material in which the magnetization deteriorates by the coefficient of thermal change of ℃, which is a certain time elapses after the operation of the CRT, resulting in thermal expansion of the second grid electrode 24 of the electron gun 20 and a charge component. When convergence drift occurs in the '-' direction, it is compensated in the opposite direction of the '+' direction.

As an example, the relationship between the heat and the magnetization amount of the auxiliary magnet ring 52, which is an object of the present invention, is well shown in Table 1. Here, the auxiliary magnet ring 52 is a ferrite material magnetized to 9.0 Gauss and is in direct contact with the neck N heated by receiving the heat of the electron gun 20. Experiment with a sample of.

TABLE 1

Sample temperature One 2 3 4 5 Value 100 8 7.7 8.1 8 7.9 8.1 90 8.3 8.2 8.3 8.2 8.1 8.3 85 8.4 8.4 8.3 8.4 8.3 8.4 80 8.5 8.4 8.5 8.4 8.5 8.5 75 8.5 8.5 8.5 8.5 8.5 8.5 70 8.6 8.6 8.6 8.6 8.6 8.6 65 8.7 8.7 8.6 8.7 8.6 8.7 60 8.7 8.7 8.7 8.7 8.7 8.7 55 8.8 8.8 8.7 8.7 8.8 8.8 50 8.8 8.8 8.8 8.8 8.8 8.8 45 8.9 8.9 8.8 8.9 8.8 8.9 40 8.9 8.9 8.9 8.9 8.9 8.9 39 9 8.9 8.9 9 8.9 9 37 9 9 9 9 9 9

Based on the results shown in Table 1, the convergence drift compensation action of the auxiliary magnet ring 52 according to the present invention is shown in FIG.

As shown in the figure, it can be seen that the convergence drift CD2 in the case of applying the auxiliary magnet ring 52 according to the present invention is significantly compensated and reduced in its total change amount than the convergence drift CD1 according to the prior art.

Specifically, in the state in which the auxiliary magnet ring 52 is magnetized to 9.0Gauss initially, convergence drift in the '+' direction due to thermal expansion of the first grid electrode 22 of the electron gun 20 is applied to the prior art. It can be adjusted and compensated up to +0.03 mm, which is reduced from +0.05 mm.

At this time, the compensation action in the '-' direction by the auxiliary magnet ring 52 lasts for 10 to 15 minutes when the temperature of the neck (N) reaches 37 to 40 ° C, after which -0.2 as shown in Table 1 below. Magnetization deterioration occurs by the coefficient of thermal change of% / ° C., on the contrary, the convergence drift in the '−' direction by the second grid electrode 24 and the charge component of the electron gun 20 is adjusted and compensated in the '+' direction. . As a result, the convergence drift according to the present invention is the result of the maximum change of -0.03 mm at the time point 120-150 minutes after the operation of the CRT, which can achieve the effect of reducing the amount of drift variation of the total convergence to 0.06 mm have.

In addition, in the case of using an alnico material, the auxiliary magnet ring 52 of the present invention causes demagnetization weight degradation by a heat change coefficient of −0.02% / ° C., so that the second grid electrode 24 and the charge component of the electron gun 20 are deteriorated. Convergence drift in the '-' direction is adjusted and compensated in the '+' direction.

As can be seen through the configuration and operation described above, the convergence compensation device of the color CRT according to the present invention substantially solves the problems of the prior art.

That is, the present invention employs a quadrupole magnetized auxiliary magnet ring to compensate for the convergence drift caused by thermal expansion of the first grid electrode of the electron gun at the beginning of the operation of the CRT. In this case, the convergence caused by the second grid electrode and the charge component may be adjusted and compensated by using the characteristic of demagnetization amount deteriorated.

Therefore, according to the present invention, the interval (OCV) between the R and B electron beams formed on the screen can be kept to a minimum so as to be close to the initial setting value of the CRT. Can improve the effect.

Claims (6)

In a color CRT tube which realizes an image by collecting electron beams emitted from an electron gun installed in a neck at one point on a screen using three pairs of convergence purity magnets mounted on a holder, and then scanning them on the screen using a deflection yoke. Install an auxiliary magnet ring magnetized to at least four poles and having an opening on the front surface of the holder so as to be exposed around the neck. Convergence compensation device of a color CRT characterized by being fixed by. The apparatus of claim 1, wherein the auxiliary magnet ring is spaced apart from the neck outer circumferential surface by 0.1 to 2.0 mm. The apparatus of claim 1, wherein the auxiliary magnet ring is in direct contact with the neck outer circumferential surface. The apparatus for compensating convergence of a color CRT according to claim 1, wherein the auxiliary magnet ring is provided between the second grid electrode of the electron gun and the deflection yoke. The apparatus for compensating convergence of a color CRT according to any one of claims 1 to 4, wherein the auxiliary magnet ring deteriorates the magnetization amount at -0.2% / ° C above 37-40 ° C. The apparatus for compensating convergence of color CRTs according to any one of claims 1 to 4, wherein the auxiliary magnet ring deteriorates the magnetization amount at −0.02% / ° C. at 37-40 ° C. or more.