JPH08315749A - Cathode-ray tube - Google Patents

Abstract

PURPOSE: To provide a cathode ray tube so that discharge is not caused between an insulating support body to fix plural electrodes of an electron gun and an insulating coating film of a resistor. CONSTITUTION: A cathode-ray tube having an electron gun to which plural electrodes are integrally fixed by a bar-shaped insulating support body 10, a resistor 30 arranged along its insulating support body and a suppressor ring 26 which is installed on a prescribed electrode of the electron gun and surrounds the insulating support body and the resistor, is provided. Insulating covering of a surface being the insulating support body side of the resistor is formed in a thick film thickness in the vicinity of a suppressor ring as well as in a shape having a projecting part having a thick film thickness between the vicinity of this suppressor ring and a high voltage impressing terminal 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 such as a color picture tube, and more particularly to a cathode ray tube having a resistor arranged inside the tube along an electron gun.

[0002]

2. Description of the Related Art Generally, a color picture tube has a vacuum envelope composed of a panel 1 and a funnel 2 joined to the panel 1 as shown in FIG. A phosphor screen 3 including a three-color phosphor layer that emits red light is formed, and a shadow mask 4 is arranged inside the phosphor screen 3 so as to face the phosphor screen 3. On the other hand, in the neck 5 of the funnel 2, an electron gun 7 that emits the three electron beams 6 is arranged. Then, the three electron beams 6 emitted from the electron gun 7 are transmitted to the funnel 2
The fluorescent screen 3 is deflected by a magnetic field generated by a deflecting device 8 mounted on the outside of the device, and the phosphor screen 3 is horizontally and vertically scanned to display a color image.

The electron gun 7 has various structures, one of which is shown in FIG. The electron gun 7 includes three cathodes K arranged in a line in a direction perpendicular to the plane of the paper, three heaters H for heating the cathodes K, and the first to the third cathodes K sequentially arranged in the phosphor screen direction. 6th grids G1 to G6, 5th and 6th
Two intermediate electrodes Gm arranged between the grids G5 and G6
1, Gm2 and the sixth grid G6 are provided with a convergence electrode C attached to the phosphor screen side, and each electrode other than the convergence electrode C is integrally fixed by a pair of rod-shaped insulating supports 10. ing.

In this electron gun 7, the fifth grid G5, 2
The intermediate electrode Gm1, Gm2 and the sixth grid G6 finally fluoresce the electron beam from the electron beam forming part formed by the cathode K and the first to third grids G1 to G3 which are successively adjacent to the cathode K. A focusing main lens portion is formed on the body screen. A high voltage of 25 to 30 kV is applied to the sixth grid G6, which is the final accelerating electrode, and a fifth grid G5, which is the focusing electrode, is applied to the fourth grid G4 and the electrode forming the electron beam forming unit. Higher than the applied voltage, the sixth grid G6
An intermediate voltage lower than that applied to the fifth grid G5 is applied to the intermediate electrodes Gm1 and Gm2, and a voltage lower than the voltage applied to the sixth grid G6 is applied to the intermediate electrodes Gm1 and Gm2. Is applied.

Generally, the voltage applied to each electrode of the electron gun of the cathode ray tube is the same as the high voltage applied to the final accelerating electrode.
Supply from an anode terminal 12 provided on the large-diameter portion of the funnel 2 through a valve spacer 14 which is attached to the inner conductive film 13 applied and formed on the inner surface of the funnel 2 and the convergence electrode C so as to be in pressure contact with the inner conductive film 13. Is
For the other electrodes, the stem 1 that seals the end of the neck 5
5 is supplied via a stem pin 16 that penetrates airtightly (see FIGS. 5 and 6).

However, when a relatively high intermediate voltage such as the fifth grid G5 and the two intermediate electrodes Gm1 and Gm2 of the electron gun 7 shown in FIG. Since it is narrow, the withstand voltage of the socket connected to the stem 15 and the stem pin 16 becomes a problem.
Therefore, as for the electron gun 7, as shown in FIG. 6, a resistor 18 is arranged on the back surface side (the surface side facing the inner surface of the neck) of the one insulating support 10 that integrally fixes the electrodes. The resistor 18 divides the high voltage applied to the sixth grid G6 and supplies it to the fifth grid G5 and the two intermediate electrodes Gm1 and Gm2.

As shown in FIG. 7, the resistor 18 has a high resistance element 21 formed in a meandering pattern on one surface of an insulating substrate 20 made of alumina ceramic, and is connected to the resistance element 21. It is composed of a plurality of low resistance terminal portions 22 formed on one surface of the insulating substrate 20 and a glass insulating coating 23 having a constant thickness that covers the insulating substrate 20 together with the resistance element 21, and each terminal portion 22 is formed of metal The structure is formed with a tab attached. In particular, the glass insulating coating 23 on the surface facing the insulating support for integrally fixing a plurality of electrodes of the electron gun is formed to have a thickness of 170 μm or more in order to improve withstand voltage characteristics.

Further, with respect to the electron gun 7, for the purpose of stabilizing the charging potential of the inner wall of the neck 5 in which the electron gun 7 is arranged, as shown in FIG. 6, a conductive film is formed on a predetermined portion of the inner wall of the neck 5. Suppressor ring 2 for forming 25
6 is provided. The suppressor ring 26 is attached to the fifth grid G5 and surrounds the insulating support 10 and the resistor 18.

However, when the color picture tube is constructed as described above, the following problems occur. That is, in general, in a cathode ray tube to which a high voltage is applied, in order to improve the withstand voltage characteristics, a pulse having a peak voltage of about 2 to 3 times the normal operating voltage is applied to the electrode of the electron gun after exhaustion in the manufacturing process. A high voltage is applied to forcibly generate a discharge, and the discharge energy causes a withstand voltage treatment to remove burrs and deposits on the electrodes that cause a decrease in withstand voltage.

When such a withstand voltage treatment is applied to the color picture tube, as shown in FIG. 8, the rod-shaped insulating support 10 integrally fixing the electrodes of the electron gun is applied by the pulsed high voltage. A potential difference is generated between the resistor 18 and the glass insulating coating 23, and a discharge 28 is generated between them. In the portion where the discharge 28 occurs, the temperature rises due to the collision of electrons, and gas is released. When the gas is released in this manner, the degree of vacuum locally deteriorates, so that the discharge is further promoted. However, during the withstand voltage treatment, the suppressor ring 26 is connected to the low voltage side, so that the discharge 28 starting from the high voltage side is gradually suppressed.
When the voltage spreads in the direction and a high voltage is applied to the vicinity of the suppressor ring 26, a large potential difference is generated between both surfaces of the resistor 18. As a result, when this potential difference exceeds the withstand voltage of the resistor 18, a dielectric breakdown that penetrates the glass insulating coating 23 occurs, the glass insulating coating piece 29 generated by the dielectric breakdown is lost, and a part of the glass insulating coating piece 29 is removed. It adheres to the electron beam passage hole of the and causes a problem such as deterioration of screen quality.

[0011]

As described above, a resistor is arranged on the back side of a rod-shaped insulating support body to which a plurality of electrodes of an electron gun are integrally fixed, as described above, and the electron gun is formed by this resistor. The high voltage applied to the final accelerating electrode is divided so that a predetermined voltage of the electron gun is supplied with a medium voltage lower than the high voltage applied to the final accelerating electrode, and the electron gun is disposed. For the purpose of stabilizing the charging potential of the inner wall of the neck,
There is a color picture tube in which a suppressor ring surrounding an insulating support and a resistor is attached to a predetermined electrode of an electron gun. Conventionally, the resistor has a high resistance resistance element formed in a meandering shape on one surface of an insulating substrate made of alumina ceramic, and a low resistance resistance element formed on one surface of the insulating substrate connected to the resistance element. It is composed of a plurality of terminal portions and a glass insulating coating of a certain thickness that covers the resistance element and the insulating substrate, and is formed in a structure in which a metal tab is attached to each terminal portion 22. In particular, the glass insulating coating on the surface side facing the insulating support that integrally fixes a plurality of electrodes of the electron gun is formed to have a thickness of 170 μm or more in order to improve withstand voltage characteristics.

However, if the color picture tube is constructed as described above, the glass of the rod-shaped insulating support body and the resistor which integrally fix the respective electrodes of the electron gun at the time of the withstand voltage treatment performed in the manufacturing process of the color picture tube. When a discharge occurs between the insulating coating and this spreading in the suppressor ring direction connected to the low voltage side, a large potential difference between both sides of the resistor causes a dielectric breakdown through the glass insulating coating. Every
The glass insulation coating piece caused by the dielectric breakdown is missing,
A part of it adheres to the electron beam passage hole of the shadow mask and causes a problem such as deterioration of screen quality.

The present invention has been made to solve the above-mentioned problems, and a resistor is arranged along a rod-shaped insulating support body that integrally fixes a plurality of electrodes of an electron gun.
Further, in a cathode ray tube in which the above-mentioned insulating support and a suppressor link surrounding the resistor are attached to a predetermined electrode of the electron gun, the insulating support and the glass insulating coating of the resistor arranged along the insulating support are The purpose is to create a structure in which discharge is unlikely to occur.

[0014]

An electron gun in which a plurality of electrodes are integrally fixed to a neck of a vacuum envelope by a rod-shaped insulating support, a resistor and an electron gun arranged along the insulating support. Is equipped with a suppressor ring that is attached to a predetermined electrode and surrounds an insulating support and a resistor. The resistor supplies an insulating substrate, a resistance element formed on the surface of the insulating substrate, and a high voltage to the resistance element. For supplying a voltage obtained by dividing the high voltage by a resistance element to a predetermined electrode of the electron gun and a ground connection terminal for grounding the resistance element In a cathode ray tube formed in a structure having a plurality of terminal portions each including a resistance element and an insulating coating that covers the resistive element and the insulating substrate, the insulating coating on the surface of the resistor on the insulating support side is suppressed. The film thickness in the vicinity grayed, and was formed into a shape having a thick convex portions of the film thickness between the suppressor ring near the high voltage supply terminal.

[0015]

As described above, the insulating coating on the surface on the insulating support side of the resistor, which is arranged along the rod-shaped insulating support for integrally fixing the plurality of electrodes of the electron gun, is formed near the suppressor ring. Is thick and has a thick projection between the suppressor ring and the high-voltage supply terminal, a voltage higher than the normal operating voltage is applied to the electrodes of the electron gun during withstand voltage processing. However, the discharge between the insulating support that fixes the multiple electrodes of the electron gun together and the insulating coating of the resistor is less likely to proceed in the suppressor ring direction, and it is possible to prevent the insulating coating from being broken due to damage. it can.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 3 shows a color picture tube which is one of the embodiments. This color picture tube has a vacuum envelope composed of a panel 1 and a funnel-shaped funnel 2 joined to the panel 1, and a three-color phosphor that emits blue, green, and red light on the inner surface of the panel 1. A phosphor screen 3 composed of layers is formed, and a shadow mask 4 is arranged inside the phosphor screen 3 so as to face the phosphor screen 3. On the other hand, funnel 2
An electron gun 7 and a resistor 30, which will be described later, that emit the three electron beams 6 are arranged in the neck 5. Further, the large-diameter portion 31 of the funnel 2 is provided with the anode terminal 12, and the inner conductive film 13 is formed by coating from the inner surface of the large-diameter portion 31 to the inner surface of the adjacent portion of the neck 5. And
A three-electron beam 6 emitted from the electron gun 7 is deflected by a magnetic field generated by a deflecting device 8 mounted outside the funnel 2, and the phosphor screen 3 is horizontally and vertically scanned to form a color image. It is formed in a display structure.

As shown in FIG. 1, the electron gun 7 includes three cathodes K arranged in a line in a direction perpendicular to the plane of the drawing, three heaters H for heating the cathodes K, and the cathode K. First to sixth grids G1 to G6 sequentially arranged in the phosphor screen direction, and two intermediate electrodes Gm1 and G arranged between the fifth and sixth grids G5 and G6.
It has a convergence electrode C attached to the phosphor screen side of m2 and the sixth grid G6, and the electrodes other than the convergence electrode C are integrally fixed by a pair of rod-shaped insulating supports 10. In order to stabilize the charging potential of the inner wall of the neck 5, a pair of rod-shaped insulating supports 10 and a suppressor ring 26 surrounding the resistor 30 described below are attached to the fifth grid G5.

In this electron gun 7, the cathode K and the first to third grids G1 sequentially adjacent to the cathode K are provided.
G3 to G3 form an electron beam forming unit for controlling the emission of electrons from the cathode K and focusing the emitted electrons to form an electron beam. The third to sixth grids G3
.About.G6 form an electron lens portion for accelerating and focusing the electron beam from the electron beam forming portion on the phosphor screen. Especially the fifth grid G5, two intermediate electrodes Gm
1, Gm2 and the sixth grid G6 form a main lens portion that finally focuses the electron beam on the phosphor screen.

A high voltage of 25 to 30 kV is applied to the sixth grid G6, which is the final accelerating electrode forming the main lens portion, from the anode terminal 12 of the large diameter portion 31 of the funnel 2 to the inner conductive film 13 and the convergence electrode. It is applied via the valve spacer 14 and the convergence electrode C which are attached to C and are in pressure contact with the inner conductive film 13. The voltage applied to the sixth grid G6 is higher than the voltage applied to the fourth grid G4 divided by the resistor 30 and the respective electrodes forming the electron beam forming part to the fifth grid G5 which is the focusing electrode. A lower medium voltage is applied. Further, a voltage higher than the voltage applied to the fifth grid G5 divided by the resistor 30 and lower than the voltage applied to the sixth grid G6 is applied to the intermediate electrodes Gm1 and Gm2.

With respect to the electron gun 7, the resistor 30 is arranged on the back side (the side facing the inner surface of the neck) of the one insulating support 10 which fixes the respective electrodes integrally, as shown in FIG. And an insulating substrate 33 made of alumina ceramic,
A relatively high resistance resistance element 34 mainly composed of ruthenium oxide and glass is formed on one surface of the insulating substrate 33 and has a relatively high resistance, and the resistance element 34 formed on one surface of the insulating substrate 33. A plurality of relatively low resistance (5 in the illustrated example) terminal portions 35a to 35e which are mainly composed of ruthenium oxide and are connected to the resistor element 34 and the insulating substrate by avoiding the plurality of terminal portions 35. The glass insulating coating 36 covering almost the entire surface of the terminal 33 and the holes that penetrate the insulating substrate 33 provided in the respective terminal portion forming portions are fixed to the terminal portions 35a to 35a.
And a metal tab 37 connected to 35e. The terminal portion 35a located at one end of the plurality of terminal portions 35a to 35e is a high voltage supply terminal for supplying a high voltage to the resistance element 34, and is connected to the convergence electrode by the metal tab 37. ing. The terminal portion 35b located at the other end is a ground connection terminal for grounding the resistance element 34, and is directly or further via a variable resistor by the metal tab 37 via the stem pin 16 (see FIG. 1). Grounded. The intermediate terminal portions 35c to 35e are electrode connection terminals for supplying a predetermined voltage to the fifth grid and the two intermediate electrodes,
5th grid and 2 via metal tabs 37 respectively
Are connected to the intermediate electrodes.

In particular, in this resistor 30, the insulating coating 36 on the surface side facing the insulating support for integrally fixing the electrodes of the electron gun has a thick projection 39a near the suppressor ring. Further, between the suppressor ring and the high voltage supply terminal portion 35a located at one end,
It is formed in a shape having a plurality of thick projections 39b.

The insulating coating 36 of such a resistor 30 is
It can be formed by multiple printing by screen printing. That is, after the resistance element 34 and the terminal portions 35a to 35e are formed on one surface side of the insulating substrate 33, the other surface of the insulating substrate 33 and the terminal portion 3 of the one surface are formed.
The first layer of the insulating coating 36 is screen-printed on the portions other than 5a to 35e. Then, the convex portions 39a, 3a are formed on the first layer.
It can be formed by screen-printing the second layer corresponding to 9b.

By the way, the insulating coating 36 on one surface side facing the insulating support 10 of the resistor 30 arranged on the back of the insulating support 10 integrally fixing the respective electrodes of the electron gun 7 in this way, If it is formed in a shape having thick film thicknesses 39a and 39b in the vicinity of the suppressor ring 26 and between the vicinity of the suppressor ring 26 and the high voltage supply terminal portion 35a, the electrode of the electron gun 7 is formed in the process of manufacturing the color picture tube. When a withstand voltage treatment is performed by applying a high voltage of 2 to 3 times the normal operating voltage, a potential difference generated between the insulating support 10 and the insulating coating 36 on one surface side facing the insulating support 10. As a result, even if a discharge is generated between the insulating support 10 and the insulating coating 36, this discharge is unlikely to proceed in the suppressor ring 26 direction. That is, in the conventional structure in which the convex portion is not provided, the contact portion between the insulating coating of the resistor and the insulating support serves as the discharge progress path, but the resistor 30 of this example
Then, by adopting a structure in which the convex portions 39a and 39b are provided on the insulating coating, it is possible to form a portion that does not contact the insulating support 10, thereby cutting off the discharge progress path, or
The path itself can be lengthened even if it is not cut off, and the discharge can be made difficult to proceed in the suppressor ring 26 direction.

Therefore, the discharge generated between the conventional insulating support and the insulating coating gradually spreads in the suppressor ring direction, and it is possible to prevent the insulating coating from being destroyed due to the large potential difference in the vicinity of the suppressor ring. It is possible to prevent the deterioration of the screen quality caused by the adhered insulating coating piece adhering to the electron beam passage hole of the shadow mask 4. Moreover, sufficient withstand voltage processing can be performed, and the withstand voltage characteristic of the color picture tube can be improved.

That is, in the conventional color picture tube in which the resistor is arranged, the breakdown of the insulating coating of the resistor is caused by 10 to 50% by the withstand voltage treatment, but in the color picture tube in which the resistor of this example is arranged, The breakdown of the insulating coating could be 2% or less.

The convex portion between the suppressor ring of the insulating coating of the resistor and the high voltage supply terminal is not limited to the shape shown in FIG. 2, and as shown in FIG. 4 (a), for example. In addition, a plurality of convex portions 39b may be provided across the insulating substrate in the width direction. Further, it is not always necessary to provide a plurality of convex portions 39b, and as shown in FIG. 7B, providing only one convex portion 39b provides a sufficient effect.

[0028]

EFFECT OF THE INVENTION An electron gun in which a plurality of electrodes are integrally fixed by a rod-shaped insulating support in a neck of a vacuum envelope, a resistor arranged along the insulating support and a predetermined electrode of the electron gun. Mounted on the insulating support and a suppressor ring surrounding the resistor, the resistor including an insulating substrate, a resistance element formed on the surface of the insulating substrate, and a high voltage for supplying a high voltage to the resistance element. A plurality of voltage supply terminal portions, an electrode connection terminal portion for supplying a voltage obtained by dividing the high voltage by the resistance element to a predetermined electrode of the electron gun, and a ground connection terminal portion for grounding the resistance element. In a cathode ray tube formed in a structure having a terminal portion of and a resistance element and an insulation coating covering the insulation substrate, the insulation coating on the surface of the resistor on the insulation support side is formed in the vicinity of the suppressor ring. If it is formed to be thick and has a thick projection between the suppressor ring and the high voltage supply terminal, a voltage higher than the normal operating voltage is applied to the electrode of the electron gun during the withstand voltage treatment. However, the discharge between the insulating support that integrally fixes the plurality of electrodes of the electron gun and the insulating coating of the resistor is less likely to proceed in the suppressor ring direction, and it is possible to prevent the insulating coating from being broken due to destruction. . As a result, it is possible to prevent the deterioration of the screen quality caused by the insulating coating piece that is missing due to this destruction adhering to the electron beam passage hole of the shadow mask 4. Moreover, sufficient withstand voltage processing can be performed, and withstand voltage characteristics of the cathode ray tube can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part configuration of a color picture tube which is an embodiment of the present invention.

FIG. 2 (a) is a plan view showing the configuration of the resistor,
FIG.2 (b) is the BB sectional drawing.

FIG. 3 is a diagram showing a configuration of a color picture tube which is an embodiment of the present invention.

FIG. 4 (a) and FIG. 4 (b) are diagrams showing different configurations of resistors.

FIG. 5 is a diagram showing a configuration of a conventional color picture tube.

FIG. 6 is a diagram showing a main part configuration of a conventional color picture tube.

FIG. 7 is a diagram showing a configuration of a conventional color picture tube resistor.

FIG. 8 is a diagram for explaining a problem of a conventional color picture tube.

[Explanation of symbols]

 5 ... Neck 7 ... Electron gun 10 ... Rod-shaped insulating support 12 ... Anode terminal 13 ... Inner conductive film 14 ... Valve spacer 26 ... Suppressor ring 30 ... Resistor 33 ... Insulating substrate 34 ... Resistor element 35a ... High voltage supply terminal part 35b ... Earth connection terminal part 35c to 35e Electrode connection terminal part 36 ... Insulation coating 39a, 39b ... Convex part C ... Convergence electrode G5 ... Fifth grid G6 ... Sixth grid Gm1, Gm2 ... Intermediate electrode

Claims (1)

[Claims] 1. An electron gun in which a plurality of electrodes are integrally fixed in a neck of a vacuum envelope by a rod-shaped insulating support, a resistor arranged along the insulating support, and a predetermined part of the electron gun. A suppressor ring attached to the electrode and surrounding the insulating support and the resistor is provided, and the resistor supplies an insulating substrate, a resistance element formed on the surface of the insulating substrate, and a high voltage to the resistance element. High voltage supply terminal part for
A plurality of terminals including an electrode connection terminal portion for supplying a voltage obtained by dividing the high voltage by the resistance element to a predetermined electrode of the electron gun and an earth connection terminal portion for grounding the resistance element. A cathode ray tube formed into a structure having a portion and an insulating coating for covering the resistance element and the insulating substrate, wherein the resistor has a film whose insulating coating on the side of the insulating support is near the suppressor ring. A cathode ray tube having a large thickness and having a convex portion having a large film thickness between the vicinity of the suppressor ring and the high voltage supply terminal portion.