JPH10188859A - Cathode-ray tube and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain rise of potential of a neck part interior wall, prevent degradation of focus and convergence generated among the neck part interior wall, an electron gun, and an electron lens, and prevent degradation of image by forming a conductive membrane on the neck part interior wall in which a CRT electron gun is incorporated. SOLUTION: In the vicinity of an interior wall of a neck part 2C opposed between a second electrode G2 constituting a pre-focus lens and a third electrode G3 , a conductive membrane 19 such as carbon, metal paste or the like is applied in advance in a ring-shape, an electron gun 5 is inserted into the neck part 2C and sealed, and a CRT1 is formed. Thereby, a potential of an inner wall of the neck part 2C is reduced to 40 to 60%, a high-pressure charge is prevented from charging up on an interior wall of the neck part 2C, and an electron beam passing through an electron lens is restrained from being affected, thereby making it possible to stabilize an orbit of the electron beam.

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 a method of manufacturing the same, and more particularly, to a cathode ray tube and a cathode ray tube capable of compensating for focus and convergence deterioration caused by electric charges charged on the inner wall of the neck of the cathode ray tube. It relates to a manufacturing method.

[0002]

2. Description of the Related Art Conventionally, in a cathode ray tube (hereinafter referred to as CRT), an electron gun is incorporated in a neck portion of a glass, and an anode voltage of 20 to 30 KV is applied to an anode button formed on a funnel of the glass tube body. It is led to electrodes and the like that constitute the main lens.

Under the influence of an electric field caused by such a high voltage, scattered electrons and electrons generated by the field emission are converted into insulators having a high secondary electron emission rate such as an inner wall of a neck portion of a CRT or bead glass of an electron gun. The collision repeatedly causes one electron to emit two or more secondary electrons, so that the potential of the inner wall of the neck gradually increases toward a high voltage.

When the potential of the inner wall of the neck portion is charged up for such a reason, protrusions such as burrs are formed on a plurality of electrodes constituting the electron gun, particularly on an electrode to which a low voltage is supplied. It is known that if there is, an electric field concentration occurs between the inner wall of the neck and the tip of the projecting burr, and eventually discharge occurs.

[0005] When such discharge occurs, there is a problem that an image is defective or an IC used for a receiver is deteriorated. To solve such inconvenience, for example, Japanese Patent Publication No. 63-10859 discloses an electronic gun. A method has been proposed in which a metal wire or ribbon is wound around a bead glass, and a conductive film is formed on the inner wall of the neck by high-frequency heating.

FIG. 7 shows a terminal portion of a neck portion of a CRT 1 for explaining such a method of forming a conductive film. An electron gun is provided in a neck portion 2c formed behind a funnel portion of the CRT. 5 are provided.

The electron gun 5 has R (red), G (green), B
The (blue) cathodes RK, GK, and BK, a first grid G ₁ and a second grid G ₂ forming a prefocus portion, a third grid G ₃ forming a main lens, and a grid G _{4 in} FIG. , the fifth grid G ₅ and the electrostatic deflector and the like are sequentially arranged. The electrostatic deflector includes a convergence plate (hereinafter, referred to as CP) and a convergence shield plate (hereinafter, referred to as CS).

Although these electron guns 5 are integrally insulated and protected by bead glasses 8U and 8D in the vertical direction (Y-axis direction),
In FIG. 7, for convenience of description, the description will be made with the bead glasses 8U and 8D attached in the X-axis direction.

The first electrode G ₁ in the electron gun 5 is usually at a potential of zero volts, the second electrode G ₂ is at a potential of 200 to 400 V, and in a unipotential electrode structure or the like, the third electrode G ₃ has a potential of 30 volts.
A high voltage of about KV is applied.

[0010] In this aspect, for the reasons described above, the inner wall of the neck portion 2c is charged up to the positive, for example burr of the first electrode G ₁ of the outer surface at a potential of the low-voltage tip and the neck portion 2c The potential difference between the inner walls becomes extremely large. As a result, causes a discharge or the like, in order to prevent them, winding a metal wire or ribbon 6 the bead glass 8U and 8D of the vicinity of the outer periphery of the first electrode G _1, outside the neck portion 2c A high-frequency current is supplied to a high-frequency induction heating coil 7 disposed in the above-described manner to evaporate the metallic ribbon 6 and deposit the conductive film 4 on the inner wall of the neck 2c.

On the other hand, in a color CRT electron gun, R,
In order to configure the electron beams emitted from the G and B cathodes RK, RG, and RB as designed values and reproduce a correct color image, the electron beams should be spotted on the phosphor screen of the panel with a spot size of a perfect circle of a predetermined size. It is necessary to have a focus characteristic to make it possible to form a convergence characteristic and a convergence characteristic to make the three electron beams R, G and B concentrate on one point on the phosphor screen.

Both characteristics are designed so that the electron beam follows a trajectory that is predetermined when the electron gun is designed. Normal,
When designing an electron gun, the potential distribution of the electron gun alone is calculated,
The charge-up of the inner wall of the neck generated in the working body is ignored.

[0013]

However, a CRT in which three electron beams of R, G, and B are focused on a phosphor screen by a three-gun type convergence lens using a shadow mask or the like is known as a jumping conver. The phenomenon caused by the electric charge that is charged up on the inner wall of the neck portion is a problem.

This jumping conversion will be described with reference to a 3-gun type CRT shown in FIG.

FIG. 8 shows a unipotential type electron gun. As in this type of electron gun, a main lens 9 is formed between a third electrode G ₃ and a fourth electrode G ₄ , and R, G, B In the case of a convergence method in which each electron beam 10 is bent, the inner wall of the neck portion 2c charges up and the potential of the inner wall of the neck portion 2c rises with time. Are designed and focused as shown by the solid line of FIG.
Is bent undefined charge voltage as the electron beam 11 shown by a chain line, dot beam R, G, the _{B R 1, G 1, B} 1
As shown in the above, just focus is not performed on the phosphor screen, resulting in a misconvergence state.

Here, when a discharge is caused between the electrodes, the charge charged on the inner wall of the neck portion 2c becomes zero at a stretch. Therefore, the convergence state becomes just convergence as designed, and again the neck portion 2c
When the electric charge on the inner wall is charged up and reaches a dischargeable potential, discharge is caused again. As described above, there is a problem that the just-focus state and the mis-focus state are repeated to make the focus state on an image unstable.

Such a phenomenon called a jumping converter is caused by one gun 3 called Trinitron (Sony trademark).
It has been found that this also occurs with a beam type electron gun.

FIG. 9 schematically shows a one-gun three-beam type CRT. The CRT 1 has a tube 2 and an electron gun 5 and a deflection yoke 12 disposed in a neck 2 c of the tube 2.
It consists of. The tube 2 is composed of a panel 2a, a funnel-shaped funnel 2b, and a neck 2c.
A phosphor of three primary colors is coated on the inner surface of the panel 2a to form a phosphor screen 3, and a color selection electrode or the like (not shown) is provided. Irradiation is performed.

The electron gun 5 in the neck 2c of the tube 2 is
G and B cathodes RK, GK, and BK, a first grid G ₁ and a second grid G ₂ that constitute a prefocus unit,
The third grid G ₃ , the fourth grid G ₄ , the fifth grid G ₅ , and the electrostatic deflector 13 constituting the main lens are sequentially arranged, and the electrostatic deflector 13 is composed of CP and CS.

These electron guns 5 are arranged vertically (in the Y-axis direction) as shown in FIG.
Are insulated and held together by the same bead glasses 8U and 8D, and are fixed to the stem base 14. Although not shown, an internal resistance dividing plate (IBR) for lowering the anode voltage by about 5% and dividing and supplying the CP is provided with an electron gun 5.
Attached to.

[0021] Since the operating so as to concentrate the three beams in the fourth electrode G ₄ parts of the above such 1 gun three-beam type CRT in the main lens, but jumping convergence does not occur in the main lens system, the second electrode G ₂ and the same problem occurs with prefocus portion between the third electrode, in particular a cathode RK and electron beam 10 near the inner wall which is charged up of the neck portion 2c emitted from the cathode BK for B for R electron beam 10 should pass through prefocus section of the second and third electrodes G ₂ and G ₃ a according to the design value as shown in a-part enlarged view of FIG. 9 in order to pass the bent like a 11 A problem that causes focus deterioration has occurred.

The present invention provides a CR that solves the above problems.
It is an object of the present invention to provide a method of manufacturing a TRT and a CRT. An object of the present invention is to use a main lens to compensate for deterioration of convergence characteristics in a CRT of a type that focuses an electron beam 10. A type of C that concentrates three beams with the main lens system like a one-gun three-beam type
CRTs and Cs that can compensate for focus characteristic degradation in RT
An object of the present invention is to provide a method for manufacturing an RT.

[0023]

A CRT according to the present invention has a built-in electron gun in a neck portion and is capable of displaying an image.
Wherein a conductive film is formed near an inner wall of the neck portion around an electron lens system formed by a plurality of electrodes of the electron gun.

In the method of manufacturing a CRT according to the present invention, an electron gun is built in the neck portion, and after evacuation processing, the metal to be vapor-deposited in advance in the vicinity of the electron lens system of the electron gun is heated from the outside of the neck portion to form the neck portion. Another method of manufacturing a CRT is to form a conductive film on the inner wall of the neck near the electron lens system of the electron gun in advance, and to build the electron gun in the neck. This is to obtain a CRT capable of displaying images.

According to the CRT and the method of manufacturing the CRT of the present invention, the conductive film is formed on the inner wall of the neck portion around the electron lens system of the electron gun, so that the occurrence of jumping convergence can be prevented, and the generation of the electron beam can be prevented. The orbit can be stabilized.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a CRT and a CRT according to the present invention will be described.
One embodiment of the manufacturing method will be described in detail with reference to FIGS. FIG. 1 is a perspective view of a main part of a CRT according to the present invention, and FIG.
FIG. 3 is a diagram illustrating another method for forming a conductive film of the CRT according to the present invention, and FIG. 4 is a perspective view illustrating an embodiment of a target plate for forming a conductive film according to the present invention. FIG. 5 is a measured data curve diagram for explaining the present invention.

First, in the present invention, for example, an electron gun is formed on a one-gun three-beam type CRT 1 by combining a plurality of electrodes similar to that shown in FIG. 9 and is set so as to obtain predetermined focus characteristics and convergence characteristics. In addition, the electron gun is sealed in the neck portion 2c so that an image can be displayed.
An operation test is performed by selecting items representative of the focus characteristics and convergence characteristics as shown in A and B.

FIG. 5A is a focus characteristic curve in which time (H) is plotted on the horizontal axis and the amount of spot size deformation (mm) is plotted on the vertical axis, and FIG. 5B is a side beam (H) on the horizontal axis plotting time (H). This is the distance (mm) between the dots of the R and B beams), and this convergence characteristic diagram shows a minus or plus value depending on whether the R beam or the B beam is used as a reference.

That is, as shown in FIG. 5A and FIG.
Neck 2 after turning on the switch to put the
4C. Focus and convergence characteristics data are collected in time series until the potential of the inner wall of the c is saturated, and the temperature-affected component is subtracted from the measured curve to obtain the data shown in FIG.
If the curves 17 and 18 as shown in FIG. 5B are obtained, it is understood that the charge is charged up on the inner wall of the neck portion 2c, and the trajectory of the electron beam is affected to deteriorate the characteristics of the electron gun. . That is, the increase in the spot size deformation and the distance between the side beam dots is affected by the electric charges charged up on the inner wall of the neck portion 2c by the electron beam.

Of course, the actual measurement may be performed by sampling measurement for each model.

In the present invention, a CRT in which charges are charged up on the inner wall of the neck portion based on the actual measurement result amount is formed with a conductive film so as to suppress the charge up.

FIG. 1 is a perspective view of an electron gun 5 in which a neck portion 2c of a one-gun three-beam CRT is partially cut, and a second electrode G ₂ and a third electrode constituting a prefocus lens are shown. carbon in advance ring near the inner wall of the neck portion 2c opposed to between G _3, the conductive film 19 such as a metal Besuto
Is applied and placed, and the electron gun 5 is inserted into the neck portion 2c and sealed to complete the CRT. For a metal base or the like, baking may be performed by a baking process or the like during the CRT process.

FIG. 2A is a sectional view taken along the line AA of FIG. 1 and shows the inner wall of the neck portion facing the prefocus lens portion formed by the gap between the second and third electrodes G ₂ and G _3. Is formed over the entire circumference.

FIG. 2B shows a case where the conductive films 19L and 19R are applied only near the inner wall of the neck portion 2c facing both sides through which the R and B electron beams pass. That is, as described with reference to FIG. 9, the electron beams affected by the positive charges charged on the inner wall of the neck portion 2c are the R and B electron beams on the left and right sides of the neck portion 2c. it is obtained by the manner of forming the conductive film 19L and 19R on the left and right only to the neck inner wall portion opposed to the focus lens where the beam passes (between G ₂ and G _3).

The above conductive films 19, 19L, and 19R are deposited on the inner wall of the neck 2c facing the electrodes constituting the electron lens system before being mounted in the electron gun 5 and the neck 2c. After the electron gun is sealed in the neck portion to complete the CRT in the same manner as described above, the target plate previously fixed to the bead glasses 8U and 8D at positions facing the electrodes constituting the electron lens system is externally (neck). The metal conductive film 19 can be applied to the inner wall of the neck portion 2c by melting from the outside of the portion 2c) by high frequency induction heating or a laser beam.

FIGS. 3 and 4 are explanatory views showing an embodiment of a method of forming such a metal vapor deposition. As shown in FIG. 3B, a gap between the second electrode G ₂ and the third electrode G ₃ is formed. 3B in order to form a conductive film 19 on the inner wall position of the neck portion 2c facing the electron lens which is to be the prefocus lens formed in FIG.
Upper and lower bead of the electron lens forming surfaces position between the one end and one end face of the third electrode G ₃ line B-B in along sectional arrow view of the second electrode G ₂ as shown in FIG. 3A Glass 8U and 8
D is provided with bead glass holding members 20 and 20.

The bead glass holding members 20 and 20 are shown in FIG.
It is configured as shown in FIG. That is, the bead glass holding member 20 has a holding plate 22 raised on both sides of the base portion 21. The holding plate 22 has a circular notch 24 so that the bead glasses 8U and 8D can be easily joined. It is formed. In this example, wing-like target plates 26 are formed on both sides of the base portion 21. This holding member 20
Can be formed, for example, by pressing a single stainless steel plate. The bead glass holding member 20, by attaching to the sides of the second and third electrodes G ₂ and G ₃ glass bead 8U and 8D, as shown in FIG. 3A, the target plate 26, of the neck portion 2c It will be arranged at four locations around the circumference.

In this embodiment, after the electron gun 5 is built in the neck portion 2c of the cathode ray tube 1 and evacuated, substantially in the final step of the manufacture of the cathode ray tube, that is, in the step before the knocking step and the aging step. Alternatively, after the aging step, as shown in FIG. 3A, a laser beam 25 is irradiated from the outside of the neck portion 2c toward four surrounding target plates 26. The irradiation conditions of the laser beam 25 are not particularly limited, but the energy is 1.0 to 1.2 J, the irradiation time is 2 to 6 msec, preferably about 4 msec, and the irradiation interval for each target plate 26 is 0.1 mm. 2s
Irradiate at ec 5 to 30 times, preferably about 10 times. The focal position is from +0 to the design surface of the target plate 26.
-0.5 mm (minus is the center direction of the neck) is preferable.

The reason why the target 26 is irradiated with the laser beam several times at a low energy is as follows.
This is for preventing the deterioration of the glass constituting the neck portion 2c. As a result of such laser irradiation, as shown in FIG. 3A, a target plate 26 made of stainless steel or the like becomes an evaporation source, and a conductive film 19 made of a metal evaporation film is formed on the inner wall of the neck 2c facing the target 26. Will be formed. The conductive film 19 is formed in an area larger than the area of the target plate 26.

The electron gun, CRT and CR according to the present embodiment
In the manufacturing method of T, the conductive film 19 is formed on the inner wall of the neck portion 2c.
Is formed, the potential of the inner wall of the neck portion 2c does not rise as in the related art. For example, 40 to 60% as compared with the case where the conductive film 19 is not formed.
The potential can be reduced to the extent. For this reason, a CRT and a method of manufacturing a CRT that does not adversely affect the electron beam passing through the electron lens without charging up high-voltage charges on the inner wall of the neck portion 2c can be obtained.

The conductive film 19 shown in FIG. 3A is deposited at a position separated from the position where the right and left electron beams for R and B pass, but the shape of the bead glass holding member 20 is changed to change the shape of the target plate 26. May be arranged near the positions indicated by E and E 'in FIG. 3A. The potential at the positions E and E 'on the inner wall of the neck portion 2c near the position where the side beam passes shown in FIG. 3A is 1 compared with the conventional 17 to 19 KV.
The potential is reduced from 0 to 11 KV and from 40 to 44%. Of course, the improvement rate of the position where the conductive film 19 is applied is 48% or more.
Although it is inferior to about 57%, the effect of lowering the potential of the charge affecting the side electron beam is sufficiently obtained, and the electron beam trajectory can be stabilized to a level at which there is no practical problem.

In the above-described embodiment, the target plate 26 made of SUS or the like is evaporated by the laser beam. However, as described with reference to FIG. 7, the conductive film can be formed by melting and evaporating the ribbon or the like by high-frequency induction heating.

In the above example, the CRT of one gun and three beams is used.
6A to 6C have been described.
This example is also applicable to the electrode configuration of the 3-gun type electron gun 5 as shown in FIG. A convergence characteristic is improved by applying or depositing a conductive film on the inner wall of the glass neck portion 2c facing the focusing electron lens 28 as shown in FIGS. 6A to 6C to suppress the occurrence of jumping convergence. Becomes possible.

That is, in the present invention, a conductive film may be formed on the inner wall of the neck portion 2c facing the electrode constituting the electron lens.

[0045]

According to the present invention, since the conductive film is formed on the inner wall of the neck portion, the potential of the inner wall of the neck portion does not rise as in the prior art. For example, the potential can be reduced to about 40 to 60% as compared with the case where no deposited film is formed. As a result, it is possible to prevent focus deterioration and convergence deterioration caused by a jumping conver or a phenomenon similar to a jumping conver generated between the inner wall of the neck portion and the electron gun or the electron lens, thereby preventing image deterioration and IC damage. CRT and C that can stabilize the electron beam trajectory as designed
An RT manufacturing method is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of a cathode ray tube showing one embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is an explanatory view of another method for forming a conductive film of the cathode ray tube of the present invention.

FIG. 4 is a perspective view showing one embodiment of a target plate for forming a conductive film of FIG. 3;

FIG. 5 is an explanatory diagram of a curve of measured data in an actual operation state.

FIG. 6 is a schematic view of a configuration of an electron gun of various CRTs applicable to the present invention.

FIG. 7 is an explanatory view of a conventional method for depositing a conductive film on a cathode ray tube.

FIG. 8 is an explanatory diagram of a cause of occurrence of jumping / comb in a conventional cathode ray tube.

FIG. 9 is a configuration diagram of a conventional one-gun three-beam cathode ray tube.

[Explanation of symbols]

1 CRT, 2c neck, G ₂ second electrode, G ₃
Third electrode, 19, 19L, 19R conductive film, 20 bead glass holding member, 26 target plate

Claims (5)

[Claims] 1. A cathode ray tube having a built-in electron gun in a neck portion and capable of displaying an image, wherein a cathode is provided near an inner wall of the neck portion around an electron lens system formed by a plurality of electrodes of the electron gun. A cathode ray tube having a conductive film formed thereon. 2. The cathode ray tube according to claim 1, wherein said conductive film is formed in a ring shape or partially on an inner wall of said neck portion. 3. The electronic film according to claim 1, wherein the conductive film forming region is a space between electrodes constituting a prefocus portion or a convergence portion electrode of the electron lens or an inner wall of a neck portion on the electrode. A cathode ray tube as described. 4. An electron gun is built in the neck portion, and after evacuation processing, the metal to be vapor-deposited in advance in the vicinity of the electron lens system of the electron gun is heated from the outside of the neck portion to form an inner wall of the neck portion. A method for manufacturing a cathode ray tube, comprising depositing a conductive film. 5. A cathode ray tube, wherein a conductive film is previously formed on an inner wall of a neck near an electron lens system of an electron gun, and the electron gun is built in the neck to obtain a cathode ray tube capable of displaying an image. Manufacturing method.