JPH06111731A - Cathode-ray tube - Google Patents

Abstract

PURPOSE: To provide a cathode-ray tube in which electron beam emitted out of an electron gun is prevented from colliding against the inner circumferential face of a funnel and occurrence of no landing of the electron beam in the rim of phosphor film is prevented. CONSTITUTION: The distance from a final accelerating electrode of an electron gun 202 to the most rear end of a deflecting yoke 203 is defined as L1 and the distance between the outlet side of the final accelerating electrode and a boundary line of a boundary between a deflecting portion in which the electron beam is deflected and moves in a curved line and a linear portion in which the electron beam linearly moves is defined as L2. Further, the inner diameter D of a neck part is defined as D and the isolation distance between the centers of electron beam passing holes formed in the electrodes composing the electron gun 202 is defined S. Electron beam emitted out of the electron gun is prevented from colliding against the inner circumferential face of the funnel and consequent occurrence of no landing of the electron beam in the rim of a phosphor film is prevented by satisfying the following relation: (L1/L2)×(D/S)=α (wherein 0.5<α<1.5).

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, and more particularly to a cathode ray tube capable of preventing an electron beam emitted from an electron gun from colliding with an inner peripheral surface of a funnel and not landing on an edge of a fluorescent film.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 1, a cathode ray tube is a panel 10 having a fluorescent film 11 formed therein, and a panel 10 sealed with the panel 10. An electron gun 22 is installed, and a funnel 20 provided with a deflection yoke 23 is provided outside the neck portion 21. Such a cathode ray tube forms one pixel by deflecting the electron beam emitted from the electron gun 22 by the scanning position where the fluorescent film 11 is scanned and is landed on the fluorescent film 11, and these pixels are gathered to form one pixel. Will form one screen. However, the deflection angle becomes larger as the screen surface of the cathode ray tube becomes larger in the lateral direction, so that the electron beam emitted from the electron gun collides with the inner surface of the funnel 20 and reaches the edge of the fluorescent film accurately. There is a problem that a phenomenon that cannot be done occurs.

As described above, the fact that the electron beam emitted from the electron gun does not reach the edge of the fluorescent film 11 by colliding with the inner surface of the funnel 20, the shape of the funnel 20, the installation state of the deflection yoke 23, the electron gun 22. It may be caused by a positional relationship between the deflection yoke 23 and the deflection yoke 23. To solve the above-mentioned problem, it is conceivable that the cone portion of the funnel 20 may be formed large so that the electron beam does not collide during deflection. If the size of the cathode ray tube becomes large, there is a problem to change the design of each part due to this,
In particular, there is a problem that it takes a long time during the evacuation process for making the inside of the cathode ray tube a vacuum.

[0004]

SUMMARY OF THE INVENTION The present invention has been devised to solve the above-mentioned problems, and its purpose is to make an electron beam emitted from an electron gun collide with a cone portion of a funnel and to It is an object of the present invention to provide a cathode ray tube capable of fundamentally solving the phenomenon that the edge cannot be accurately reached.

[0005]

In order to achieve the above-mentioned object, according to the present invention, a panel having a fluorescent film formed on the inner surface thereof and an electron gun and a deflection yoke are installed inside and outside the neck portion of the panel, respectively. In a cathode ray tube in which a funnel is sealed, the distance from the final acceleration electrode of the electron gun to the last end of the deflection yoke is L1, and the electron beam emitted from the exit side of the final acceleration electrode and the electron gun is deflected. The distance between the deflection section that is deflected by and is moved in a curved line and the boundary line between the linear section in which the electron beam linearly moves is L2, the inner diameter of the neck is D, and the electron gun is The eccentric distance between the centers of the electron beam passage holes of the electrodes is S
Then, a cathode ray tube is provided in which these relationships satisfy the following equation.

(L1 / L2) × (D / S) = α (where 0.5 <α <1.5)

[0007]

According to the cathode ray tube of the present invention, the electron beam generated when the screen surface of the cathode ray tube becomes large in the lateral direction and the deflection angle also becomes large, collides with the inner surface of the funnel portion and accurately reaches the edge portion of the fluorescent film. To prevent being landed on.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In general, a cathode ray tube is a panel 100 having a fluorescent film 101 formed on the inner surface thereof, and is sealed to the panel 100. An electron gun 202 is provided inside a neck portion 201 of the panel 100.
And a funnel 200 around which a deflection yoke 203 for deflecting an electron beam emitted from the electron gun 202 to a scanning position of the fluorescent film 101 is provided around a cone portion near the neck portion 201. It is equipped with.

In the cathode ray tube thus constructed, the screen surface of the cathode ray tube becomes laterally large, so that the electron gun 20
Although the deflection angle of the electron beam emitted from 2 becomes large,
At this time, the electron beam emitted from the electron gun collides with the inner peripheral surface of the funnel 200, and the electron beam is emitted from the fluorescent film 1.
By not landing exactly on the edge of 01,
There is a problem that the image of the peripheral portion of the fluorescent film 101 is not sharpened.

Therefore, as a result of careful examination of the cause, the present inventor has found that the above-mentioned phenomenon occurs due to the following requirements.

That is, as a factor that the electron beam emitted from the electron gun is not accurately landed on the edge of the fluorescent film,

First, the installation state of the deflection yoke and the size of the deflection angle,

Secondly, the eccentric distance between the centers of the through holes of the electron beams of the three electron guns respectively emitting the red, blue and green electron beams,

Thirdly, the distance between the boundary line which is the boundary between the deflection section in which the electron beam is deflected by the deflection yoke into a curved line from the electron gun and the straight section in which the electron beam is linearly moved, and the final acceleration electrode exit of the electron gun,

Fourth, it has been found that there is a relation with the size of the inner diameter of the neck portion to which the electron gun is attached.

Therefore, the present inventor prevents the electron beam emitted from the electron gun from colliding with the inner peripheral surface of the cone portion near the neck portion and being prevented from landing accurately on the edge of the fluorescent film. The above factors were defined as the following equations and experiments were conducted, and the results as shown in the following Tables 1 and 2 were obtained.

(L1 / L2) × (D / S) = α

(Where L1 is the distance from the exit of the final acceleration electrode of the electron gun to the rear end of the deflection yoke, L2 is the distance from the exit of the final acceleration electrode to the boundary line, and D is the electron gun. Is the inner diameter of the neck part in which
Is the eccentric distance between the centers of the electron beam passage holes of the electrodes that make up the electron gun)

[0020]

[Table 1]

[0021]

[Table 2]

As can be seen from Tables 1 and 2, the above α
When the value of is less than 0.5, the electron beam emitted from the electron gun 202 collides with the inner surface of the neck portion 201 and the fluorescent film 10
The phenomenon of not landing accurately on the edge of 1 does not occur,
When the length from the exit of the final accelerating electrode of the electron gun 202 to the boundary line is long, the phenomenon that the electron beam collides with the inner surface of the neck portion does not occur, but there is a problem that the volume of the neck portion 201 increases. there were. Therefore, as shown in the above table, when the value of α is larger than 0.5 and smaller than 1.5, the best design is possible without increasing the volume of the funnel, and the resolution of the cathode ray tube can be reduced over the entire screen. Can be uniform.

[0023]

As described above, in the cathode ray tube according to the present invention, the electron beam generated when the electron beam becomes large in the lateral direction of the screen and the deflection angle becomes large, collides with the inner surface of the neck portion and the fluorescent film. There is an advantage that the phenomenon of not being accurately landed at the edge of the funnel can be fundamentally solved, and the funnel can be designed in the uppermost state without increasing the volume thereof.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a conventional cathode ray tube.

FIG. 2 is a vertical sectional view showing a cathode ray tube according to the present invention.

[Explanation of symbols]

 100 panel 101 fluorescent film 200 funnel 202 electron gun 203 deflection yoke

Claims (1)

[Claims] 1. A panel having a fluorescent film formed on its inner surface,
In a cathode ray tube in which a funnel having an electron gun and a deflection yoke installed inside and outside the neck is sealed, a distance between the final acceleration electrode of the electron gun and the rear end of the deflection yoke is L1. A boundary line between the exit side of the final accelerating electrode, a deflection section in which the electron beam emitted from the electron gun is deflected by a deflection yoke and moves in a curved shape, and a straight section in which the electron beam moves in a straight line. And L is L, the inner diameter of the neck is D, and the eccentric distance between the centers of the electron beam passage holes of the electrodes forming the electron gun is S, these relationships satisfy the following equations. Characteristic cathode ray tube. (L1 / L2) × (D / S) = α (where 0.5 <α <1.5)