JPH10188858A - Cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate slip-off of a conductive membrane due to energization of an electron gun support member, prevent lowering of a withstand voltage and contamination of a fluorescent face, relax concentration of the electric field due to external discharge, and restrain generation of a neck crack by spacing a contact point among an end edge on a neck part side of the conductive membrane, an electron gun support member, and a neck part interior wall. SOLUTION: A conductive membrane 9 is formed on a glass interior wall face, an interior wall face of a funnel 3 is kept in a uniform potential, and a high voltage applied from an anode terminal is transmitted to an electron gun. The conductive membrane 9 comes into non-contact with an H spring 12 of the electron gun support member, and a distance among an end edge on the neck part side, the H spring 12, and the neck part interior wall is within 2mm. Thereby, when a high voltage is applied between an anode terminal and a cathode, an electron is emitted to the outside, is attracted by the high potential conductive membrane 9 and flows a course B while it is radiated to the H spring 12, and is restrained from concentrating at one part.

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 for a television receiver, and more particularly, to a cathode ray tube in which cracking of a neck portion (hereinafter referred to as neck crack) is suppressed.

[0002]

2. Description of the Related Art A cathode ray tube for projecting an image based on a signal outputted from a color signal circuit emits an electron beam into a glass bulb having a substantially flask shape as a whole and a high vacuum state inside. An electron gun is provided.

[0003] The glass bulb has a cylindrical neck portion,
A funnel formed according to the deflection angle of the deflection yoke and a panel glass forming the screen surface are joined. In this glass bulb, an electron gun is disposed in a neck portion, and an aperture grille that transmits an electron beam emitted from the electron gun and performs color selection is mounted inside the panel glass. In addition, a fluorescent screen that emits light when irradiated with an electron beam is formed on the inner surface of the panel glass.

[0004] Further, the funnel portion of the glass bulb includes:
An anode terminal for applying a high voltage to the electron gun is attached. Further, a conductive film is formed on the inner wall surface of the glass bulb from the funnel portion to the funnel portion side of the neck portion. This conductive film keeps the inner wall surface of the funnel at a uniform potential and transmits a high voltage applied from the anode terminal to the electron gun.

An electron gun that emits an electron beam includes red, green, and red light emitted from three cathodes arranged in line.
An electron beam corresponding to blue is made to intersect at the center of one main lens, and thereafter, electron beams dispersed in three directions are refracted by a concentrated polarizing plate and converged on a phosphor screen. The electron gun is assembled by fixing a plurality of electrode groups for controlling, accelerating, and converging an electron beam emitted from a cathode to a glass support rod at predetermined intervals.

A conductive piece is attached to the final electrode of the electron gun, and the conductive piece is connected to a conductive film formed on the inner wall surface of the glass bulb. As a result, a high voltage applied from the anode terminal is supplied to the electron gun via the conductive film.

[0007] The electron gun is supported by an electron gun support member called an H spring and disposed inside the neck portion. The H spring is formed by bending a metal spring material or the like so as to be elastically deformable. The H spring resiliently urges the inner wall of the neck to support the electron gun with respect to the neck.

In the cathode ray tube constructed as described above, when the power of the television receiver is turned on, the color signal output from the color signal circuit is input to the electron gun, and the electron beam is emitted toward the phosphor screen. You. The electron beam emitted from the electron gun is deflected by the magnetic field of the deflecting coil, passes through a slit formed in the aperture grill, and irradiates the phosphor screen, causing the phosphor screen to emit light. Is projected.

In a conventional glass bulb of a cathode ray tube, a conductive film is formed on an inner wall surface at a position beyond a contact point between an H spring supporting an electron gun and an inner wall of a neck portion. That is, in the conventional cathode ray tube, the H spring that supports the electron gun is resiliently urged against the inner wall of the neck portion where the conductive film is formed.

In order to stably support the electron gun, the H spring needs to be elastically urged against the inner wall of the neck portion with a strong elastic force. Then, when the H spring resiliently urges the inner wall of the neck portion on which the conductive film is formed with a strong elastic force, the conductive film is cut off by the H spring and falls off, and dust is generated. Dust generated by the shaving of the conductive film causes a reduction in withstand voltage and contamination of the phosphor screen.

Therefore, the conductive film formed on the inner wall of the glass bulb is separated from the contact point between the H spring and the inner wall of the neck so that the conductive film is not cut by the H spring.
A cathode ray tube has been proposed in which an H spring resiliently urges a portion of the inner wall of the neck portion where the conductive film is not formed.

[0012]

However, as shown in FIG. 3, in the cathode ray tube in which the conductive film 100 is separated from the contact point between the H spring 101 and the inner wall of the neck portion 102, an external discharge occurs during knocking. In this case, there is a problem that neck cracks occur frequently. That is, when a high voltage is applied between the anode terminal and the cathode, electrons are emitted to the outside, and the electrons emitted to the outside may discharge to the H spring 101 having a relatively high potential. At this time, the electrons emitted by the external discharge flow through the shortest course C to reach the H spring 101, so that the electric field concentrates on the place where the electrons flow, and the dielectric breakdown occurs in the neck portion 102 and the neck crack occurs. Frequently occur.

It is an object of the present invention to provide a cathode ray tube which prevents generation of dust due to detachment of a conductive film, reduces concentration of an electric field when external discharge occurs, and suppresses occurrence of neck crack. Aim.

[0014]

In order to solve the above-mentioned problems, a cathode ray tube according to the present invention is characterized in that a conductive film formed on the inner wall surface of a glass bulb is connected to a contact point between an electron gun support member and an inner wall of a neck portion. At the same time, the distance between the edge of the conductive film on the neck portion side and the contact point between the electron gun support member and the inner wall of the neck portion is set to be within 2 mm.

That is, a cathode ray tube according to the present invention comprises a glass bulb having a cylindrical neck at one end, an electron gun disposed in the neck, and an electron gun which is urged toward the inner wall of the neck to urge the electron gun. An electron gun support member for supporting the neck portion, an anode terminal attached to the glass bulb for applying a high voltage to the electron gun, and a high voltage formed on the inner wall surface of the glass bulb and applied from the anode terminal A conductive film that transmits the conductive film to the electron gun, the conductive film does not contact the electron gun supporting member, and the contact point between the edge on the neck portion side of the conductive film and the inner wall of the neck portion of the electron gun supporting member. Is within 2 mm.

In this cathode ray tube, since the conductive film is not in contact with the electron gun supporting member, the conductive film is not cut by the electron gun supporting member.

Further, the cathode ray tube has an edge of the conductive film,
Since the distance between the electron gun support member and the contact point between the inner wall of the neck portion is set to within 2 mm, when an external discharge occurs, a part of the electrons toward the electron gun support member is pulled by the high potential conductive film. . Therefore, in this cathode ray tube, concentration of electrolysis caused by external discharge is reduced, and neck cracks are suppressed.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the cathode ray tube according to the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, for example, a single-gun three-beam cathode ray tube 1 has a cylindrical neck portion 2 at one end, and a funnel formed into a substantially flask shape according to the deflection angle of a deflection yoke. 3 and a panel 4 joined to the other end of the funnel 3
And an electron gun 6 arranged inside the neck portion 2 and an aperture grille 7 which is a color selection mechanism attached inside the panel 4.

The funnel 3 is made of glass having a good X-ray blocking property so that the funnel 3 does not become dark brown even with the collision of an electron beam due to high voltage acceleration. The funnel 3 is formed so as to gradually become wider from one end where the cylindrical neck portion 2 is formed to the other end in accordance with the deflection angle of the deflection yoke. An anode terminal 8 for applying a high voltage to the electron gun 6 is attached to the funnel 3.

Then, a panel 4 is joined to the other end of the funnel 3, which is a wide opening, to form a glass bulb 5.

A conductive film 9 such as a carbon film is formed on the inner wall surface of the glass bulb 5 from the other end of the funnel 3 to the neck 2 side. The conductive film 9 is for keeping the inner wall surface of the funnel 3 at a uniform potential and transmitting a high voltage applied from the anode terminal 8 to the electron gun 6. Here, the conductive film 9 is not in contact with an H spring 12 described later, and the distance between the edge on the neck portion 2 side and the contact point between the H spring 12 and the inner wall of the neck portion 2 is within 2 mm. Is done. That is, assuming that the distance between the end edge of the conductive film 9 on the neck portion 2 side and the H spring 12 and the contact point on the inner wall of the neck portion 2 is S, 0 <S ≦ 2 (mm).

The main surface of the panel 4 is configured as a screen surface. On the main surface of the panel 4 serving as the screen surface, a fluorescent screen 10 that emits light by irradiation with an electron beam emitted from the electron gun 6 is formed on the inner surface thereof.

An aperture grill 7 is mounted inside the panel 4. Aperture grill 7
Transmits the electron beams of each color by transmitting the red, green, and blue electron beams emitted from the electron gun 6 so that the phosphor screen 1
Of the red, green, and blue phosphors constituting 0, only the phosphors of the corresponding emission colors are irradiated. The aperture grille 7 is supported by a frame composed of a pair of vertical frames and a pair of horizontal frames, and is mounted inside the panel 4 so as to be parallel to the main surface of the panel 4.

An electron gun 6 is provided on the neck 2. The electron gun 6 has a single electron gun structure, in which red, green, and blue electron beams emitted from three cathodes arranged in-line intersect at the center of one main lens. Thereafter, the electron beams that are discrete in three directions are refracted by the electrostatic polarizer and converge on the phosphor screen 10. And this electron gun 6
A plurality of electrode groups for controlling, accelerating, and converging the electron beam emitted from the cathode are assembled by being fixed at predetermined intervals to a glass support rod.

The conductive electrode 1 is connected to the final electrode of the electron gun 6.
1 and the conductive piece 11 is attached to the glass bulb 5.
Is connected to the conductive film 9 formed on the inner wall surface. As a result, the high voltage applied from the anode terminal 8 becomes
It is supplied to the electron gun 6 via the conductive film 9.

The electron gun 6 is supported by an H spring 12 serving as an electron gun supporting member, and is disposed inside the neck portion 2. The H spring 12 is formed by bending a metal spring material or the like so as to be elastically deformable. The H spring 12 urges the inner wall of the neck portion 2 where the conductive film 9 is not formed to support the electron gun 6 with respect to the neck portion 2. Therefore, even if the H spring 12 is resiliently urged against the inner wall of the neck portion 2 with sufficient resilience to stably support the electron gun 6, the generation of dust due to the detachment of the conductive film 9 is prevented. I will not invite you. Also,
As described above, the contact point between the H spring 12 and the inner wall of the neck portion 2 is 2 mm from the edge of the conductive film 9 on the neck portion 2 side.
Within the position.

When a high voltage is applied between the anode terminal 8 and the cathode, the thus constructed cathode ray tube 1
An electron beam emitted from the cathode, controlled, accelerated, and focused by the plurality of electrode groups is deflected by the magnetic field of the deflection coil, and is emitted from the electron gun 6 toward the fluorescent screen 10. Then, the electron beam emitted from the electron gun 6 passes through the aperture grille 7 and irradiates the phosphor screen 10 so that the phosphor constituting the phosphor screen 10 emits light, and an image is displayed on the main surface of the panel 3. It is projected.

When a high voltage is applied between the anode terminal 8 and the cathode, as shown in FIG. 2, electrons are emitted to the outside, and the electrons emitted to the outside are applied to the H spring 12 having a relatively high potential. It may discharge. On this occasion,
The electrons emitted by the external discharge try to flow through the shortest course A and reach the H spring 12, but the high potential conductive film 9 is located at a position within 2 mm from the contact point between the H spring 12 and the inner wall of the neck portion 2. Since it is formed, a part of the electrons emitted by the external discharge is pulled by the conductive film 9, flows through the course B, and reaches the conductive film 9.

Therefore, in the cathode ray tube 1, electrons emitted by the external discharge do not flow intensively to one portion of the neck portion 2, so that concentration of electrolysis is reduced and neck cracks are suppressed.

[0031]

EXAMPLES In order to confirm the effects of the present invention, the following experiments were conducted. That is, different types of cathode ray tubes A, B,
C and D were manufactured, and the distance S between the end of the conductive film in the cathode ray tube on the neck side and the contact point between the H spring and the inner wall of the neck was changed. The relationship between the distance S between the contacts and the occurrence of neck cracks was investigated. Table 1 shows the results.

The cathode ray tubes of models A, B, and C have a neck inner diameter of 23.9 mm (minimum value), a neck outer diameter of 29.1 mm (design center value), and a glass thickness of 2.44.
mm (design center value), and the cathode ray tube of model D has a neck inner diameter of 26.0 mm (minimum value), a neck outer diameter of 32.5 mm (design center value), and a glass thickness of 3.00.
mm (design center value).

[0033]

[Table 1]

From the results shown in Table 1, the rate of occurrence of neck cracks can be reduced by setting the distance S between the contact point between the H spring and the inner wall of the neck within 2 mm for each of the types A, B, C and D. Was found to be within 0.1%.

On the other hand, when the distance S between the contact point between the H spring and the inner wall of the neck portion exceeds 2 mm, the rate of occurrence of neck cracks is more than doubled. Was very high at 0.35%.

[0036]

In the cathode ray tube according to the present invention, the distance between the edge of the conductive film on the neck portion side and the contact point between the electron gun support member and the inner wall of the neck portion is within 2 mm. When this occurs, concentration of electrolysis caused by external discharge is reduced, and neck cracks are suppressed.

In this cathode ray tube, since the conductive film and the electron gun support member are not in contact with each other, the electron gun support member has an elastic force sufficient to stably support the electron gun. Even if the inner wall of the neck portion is elastically urged, no dust is generated due to the detachment of the conductive film, and a reduction in withstand voltage due to the generation of the dust and contamination of the fluorescent screen are prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cathode ray tube.

FIG. 2 is an enlarged sectional view of a main part of a neck portion of the cathode ray tube.

FIG. 3 is an enlarged sectional view of a main part of a neck portion of a conventional cathode ray tube.

[Explanation of symbols]

1 cathode ray tube, 2 neck, 5 glass bulb, 6
Electron gun, 8 anode terminal, 9 conductive film, 12 H spring

Claims (1)

[Claims] A glass bulb having a cylindrical neck portion at one end; an electron gun disposed in the neck portion; and a resiliently urging the inner wall of the neck portion to move the electron gun against the neck portion. An electron gun supporting member to be supported; an anode terminal attached to the glass bulb for applying a high voltage to the electron gun; and a high voltage formed on the inner wall surface of the glass bulb and applied from the anode terminal. A conductive film for transmitting a voltage to the electron gun, wherein the conductive film does not contact the electron gun support member, and an edge of the conductive film on a neck portion side and a neck inner wall of the electron gun support member. Wherein the distance between the contacts is within 2 mm.