JPH08106863A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE: To eliminate the six-pole magnetic field component of a bipolar purity magnet and provide a high image quality over the whole area of a screen by using, as magnets of a convergence device on a neck part, two magnets having divided poles in which N- and S-poles are divided in the radial direction of the neck part, and setting the angle formed between the divided poles of the same magnetic pole to a prescribed value. CONSTITUTION: A convergence device 7 has two-in-a-set six-pole magnets 9a, 9b for static convergence correction, quadrupole magnets 10a, 10b, and bipolar magnets 11a, 11b for purity correction successively provided in electron beam emitting direction on the outer circumferential surface of a neck part 5 in order to focus the electron beams emitted from an electron gun 6 to one point on a phosphor screen 2. N-pole and S-pole are magnetized in positions mutually separated by 60 in the magnets 9a, 9b, and in positions mutually separated by 90 in the magnets 10a, 10b, respectively. The magnets 11a, 11b have divided poles in which N-pole and S-pole are halved in the radial direction of the neck part 5, respectively, and they are magnetized so that the angle formed by the respective divided poles of the same magnetic pole are 30-50 deg.. Thus, the magnetic field distribution of the magnets 11a, 11b is substantially uniformed, and no color shade is caused even when a pair of magnets are regulated so as to enhance color purity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube used for televisions, displays and the like.

[0002]

2. Description of the Related Art A conventional color cathode ray tube has a two-pole purity magnet and a six-pole static magnet, each of which has an annular shape on the outer peripheral surface of the neck and is composed of two pieces in order to reduce color misregistration. A magnet and a 4-pole static magnet
An electron beam is focused on a screen portion of the cathode ray tube by a convergence device having a structure in which the electron beam is sequentially emitted from an in-line type electron gun inside the neck portion. Also, a 2-pole purity magnet has an N-pole and an S-pole.
The poles are located approximately 180 degrees apart, the 6-pole static magnets are alternately located 60 degrees apart from the north and south poles, and the 4-pole static magnets are alternating 90 degrees apart from the north and south poles. It is located (JP-A-61-208725).

[0003]

However, in the conventional color cathode ray tube, when a pair of two-pole purity magnets are adjusted in order to improve color purity, color misregistration occurs,
Next, if readjustment is performed with a pair of 6-pole static magnets in order to eliminate this color misregistration, there is a problem that the image quality deteriorates, especially in the upper and lower portions of the screen.

Analysis of the cause revealed that the magnetized state of the pair of two-pole purity magnets was the cause. That is, as shown in FIG. 7, the magnetized state of the two-pole purity magnet does not have one N-pole and one S-pole at positions separated by 180 degrees, but as shown in FIG. , N pole and S
Each pole has a polarization divided into two, and the angle formed between the polarizations of the same magnetic poles is 60.
It was more than once. Therefore, two of the two-pole purity magnet
The divided magnetic field distribution was not uniform but pincushion-shaped.

A pair of two having a pincushion-like magnetic field distribution
Since the pole purity magnet has a magnetic field component with 6 poles,
When the adjustment is made to improve the color purity, the magnetic field components of the 6 poles gradually increase, causing a large color shift. Then a pair of 6
With the static magnet of the pole, readjusting to eliminate this large color shift, especially in the upper and lower parts of the screen,
It is considered that the spot shape of the electron beam was greatly distorted and the image quality was deteriorated.

The present invention eliminates the 6-pole magnetic field component of a 2-pole purity magnet and provides a high-quality color cathode ray tube over the entire screen.

[0007]

The color cathode ray tube of the present invention is a color cathode ray tube provided with a convergence device having a two-pole magnet constituted by at least two pairs on the outer peripheral surface of the neck portion of the bulb. The two-pole magnet has polarizations obtained by dividing the north pole and the south pole into two in the radial direction of the neck portion, and the angle formed between the polarizations of the same magnetic pole is 30 to 50 degrees. It is magnetized as follows.

[0008]

With this structure, the magnetic field distribution of the pair of two-pole magnets is substantially uniform, and color misregistration occurs even if each of the pair of two-pole magnets is adjusted in order to improve color purity. Therefore, a high-quality color image can be obtained over the entire screen.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the color cathode ray tube of the embodiment of the present invention is provided in a position close to the bulb 3 having a phosphor screen 2 of plural colors on the inner surface of the face panel 1 and the surface of the phosphor screen 2. A shadow mask 4 having a plurality of electron beam transmitting holes, an in-line type electron gun 6 provided inside the neck portion 5, and a neck portion 5 of the bulb 3.
It is composed of a convergence device 7 and a deflection yoke 8 which are sequentially provided on the outer circumference of the electron gun 6 in the direction in which the electron beam of the electron gun 6 is emitted.

As shown in FIG. 2, the convergence device 7 includes two electron beams emitted from the electron gun 6 on the outer peripheral surface of the neck portion 5 in order to focus the electron beams at one point on the phosphor screen 2. Direction in which electron beam of electron gun 6 emits 6-pole magnets 9a, 9b for static convergence correction, 4-pole magnets 10a, 10b, and 2-pole magnets 11a, 11b for purity correction Are installed in sequence. The magnetic poles of the magnets are, as shown in FIG. 3, for the 6-pole magnets 9a and 9b, for the 4-pole magnets 10a and 10b at positions where the N pole and the S pole are alternately 60 degrees apart. Are magnetized at positions where N poles and S poles are alternately separated by 90 degrees. Regarding the two-pole magnets 11a and 11b, the north pole and the south pole have polarizations divided into two in the radial direction of the neck portion 5, and the angle formed between the polarizations of the same magnetic poles is 30 degrees to 50 degrees. It is magnetized so that Preferably, the angle α between polarizations of the same magnetic pole is 40 degrees.

Next, the operation of the color cathode ray tube will be described. In the color cathode ray tube of the embodiment of the present invention, the two-pole magnets 11a and 11b have polarizations in which the N pole and the S pole are each divided into two, and the angle α formed between the polarizations of the same magnetic poles is 30 degrees to. Since the magnets are magnetized at 50 degrees, the magnetic field distributions of the two-pole magnets 11a and 11b are substantially uniform as shown in FIG. Therefore, even if a pair of two-pole magnets are adjusted in order to improve the color purity, the magnetic field component of the six poles becomes extremely small, and the color shift does not occur. Therefore, 6
Since it is not necessary to readjust the polar magnets 9a and 9b, a high-quality color image with a small distortion of the electron beam spot shape can be obtained over the entire screen.

Next, an experimental example for confirming the effects of the present invention will be described. The color cathode ray tube of the embodiment of the present invention (hereinafter referred to as the product of the present invention) has the configuration shown in FIGS.
Using a 17-inch color cathode ray tube having a neck outer diameter of 9.1 mm, the 6-pole magnet 9 of the convergence device 7 is used.
a and 9b are positions where the north pole and the south pole are alternately 60 degrees apart,
The 4-pole magnets 10a and 10b have 90% alternating N and S poles.
Two-pole magnets 11a and 11b were magnetized at positions apart from each other at an angle α of 30 to 50 degrees.

In order to compare with this, the angle α of the pair of two-pole magnets 11a and 11b shown in FIG. 3 was set to 60 °, and a conventional color cathode ray tube (hereinafter referred to as a conventional product) having the same specifications as above was also manufactured. .

In order to improve color purity, the two-pole magnet 11
Amount of electron beam spot movement on the screen 2 when a and 11b are adjusted (hereinafter referred to as a dipole magnetic field correction amount)
Then, by adjusting the 6-pole magnets 9a and 9b, the spot movement amount of the electron beam on the screen 2 portion (hereinafter referred to as 6-pole component convergence amount) for correcting the color shift due to the spot movement amount is examined. As a result, the results shown in FIG. 4 were obtained. In FIG. 4, line A is the product of the present invention,
Lines B show the conventional products, respectively.

As is apparent from FIG. 4, the product of the present invention has a value of 6 even if the dipole magnetic field correction amount is changed in order to improve the color purity.
Since the polar component convergence amount is small, there is an effect of drastically reducing the color shift. For example, when the bipolar magnetic field correction amount is 3 mm, the 6-polar component convergence amount is stable at about 0.1 mm, and the 6-polar component convergence amount is about 0 mm. It can be seen that it is reduced to about 1/8 compared with the conventional product of 0.8 mm.

The reason for this is that, as is apparent from FIGS. 5 and 6, when the angle α of the two-pole magnets 11a and 11b is 40 degrees, the strength of the magnetic field component of the six poles and the amount of convergence of the six-pole components are minimum. Therefore, the two-pole magnets 11a, 11
The magnetic field distribution of b is uniform, and the two-pole magnet 11
When the angle α of a and 11b is 30 degrees to 50 degrees, the strength of the magnetic field component of the 6 poles is small, and the amount of convergence of the 6 pole components is almost the same.
This is because the magnetic field distribution of is almost uniform.

The angle α of the two-pole magnets 11a and 11b
Is less than 25 degrees and more than 55 degrees, the barrel-shaped and pin-cushion-shaped 6-pole magnetic field components increase,
After adjusting the color misregistration, the spot shape of the electron beam was distorted, especially in the upper and lower portions of the screen, and the image quality became a problem in practical use.

[0019]

As described above, according to the present invention, the magnetic field distributions of the pair of two-pole magnets are substantially uniform, and the pair of two-pole magnets are adjusted to improve the color purity. Even if the color shift does not occur, it is possible to provide a color cathode ray tube capable of obtaining a high-quality color image over the entire screen.

[Brief description of drawings]

FIG. 1 is a front sectional view of a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the convergence device.

FIG. 3 is a magnetic pole diagram of the same 2-pole, 4-pole and 6-pole magnets.

FIG. 4 is a characteristic comparison diagram between the product of the present invention and the conventional product.

FIG. 5 is a relational diagram of the magnetic field strength of the 6-pole component with respect to the angle α of the 2-pole magnet of the present invention.

FIG. 6 is a relational diagram of a 6-pole component convergence amount with respect to an angle α of a 2-pole magnet according to the present invention.

FIG. 7 is a conceptual diagram of a magnetized state of a conventional two-pole magnet.

FIG. 8 is a magnetized state diagram of a conventional two-pole magnet.

[Explanation of symbols]

 2 Screen 3 Valve 5 Neck 7 Convergence device 11a, 11b 2-pole magnet

Claims (1)

[Claims] 1. A color cathode ray tube provided with a convergence device having a two-pole magnet constituted by a set of at least two magnets on an outer peripheral surface of a neck portion of a bulb, wherein the two-pole magnets are N-pole and S-pole. And 2 in the radial direction of the neck
A color cathode ray tube having divided polarizations and being polarized such that an angle formed between the polarizations of the same magnetic poles is 30 to 50 degrees.