JP3133352B2 - Withstand voltage treatment method for cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

 [Object of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a withstand voltage processing method for a cathode ray tube, and more particularly to a method for applying a high voltage to electrodes on an insulating support for integrally fixing a plurality of electrodes of an electron gun. The withstand voltage of a high-performance cathode ray tube in which a resistor for dividing a high voltage applied to a medium voltage application electrode to a medium voltage is arranged, and a metal ring for forming a metal deposition film is arranged on the medium voltage application electrode The present invention relates to a withstand voltage processing method for a cathode ray tube which improves characteristics.

[0002]

2. Description of the Related Art Generally, a cathode ray tube is, as shown in FIG.
Phosphor screen 2 on inner surface of faceplate 1 of envelope
Is formed, and an electron gun 5 for emitting an electron beam 4 for displaying an image on the phosphor screen 2 is provided in a neck 3 of the envelope. In particular, in a color picture tube, a shadow mask 6 is arranged inside the phosphor screen 2, and the three electron beams 4 emitted from the electron gun 5 are selected by the shadow mask 6 to form three colors constituting the phosphor screen 2. It is formed in a structure to be incident on the phosphor layer.

In general, the electron gun 5 comprises a cathode, a plurality of grids for controlling the emission of electrons from the cathode and converging the emitted electrons to form an electron beam 4, and for applying the electron beam 4 to the phosphor screen 2. A plurality of electrodes such as a plurality of grids that accelerate and converge toward the screen are sequentially arranged in the direction of the phosphor screen, and the plurality of electrodes are formed in a structure integrally fixed by a pair of insulating supports. . Of the plurality of electrodes, a relatively low predetermined low voltage is applied to a plurality of grids for controlling electron emission from the cathode and converging the emitted electrons to form an electron beam 4, A relatively high and medium voltage is applied to a plurality of grids for accelerating and converging the electron beam 4 toward the phosphor screen 2. Usually, the relatively high voltage is applied from the anode terminal 9 provided on the side wall of the cone portion 8 of the envelope to the internal conductive film 10 applied to the inner surface of the cone portion 8.
The other relatively low and medium voltages are supplied through the stem 11 sealing the end of the neck 3 where the electron gun 5 is provided. It is supplied through the stem pin 12 of the book. In a color picture tube, the above-mentioned relatively high medium and high voltages are 5 to 8 k, respectively.
V is about 20 to 30 kV.

By the way, as described above, voltages other than high voltage,
In particular, when a relatively high medium voltage is supplied via the stem pin 12, the distance between the stem pins 12 is small, so that the withstand voltage of the socket for connecting the stem 11 and the stem pin 12 to an external power source becomes a problem. There are problems such as a complicated structure.

For this reason, a means for arranging a resistor along the electron gun in the neck and dividing the high voltage supplied from the anode terminal by the resistor to obtain a medium voltage has been proposed.
No. 1561, Japanese Utility Model Application Laid-Open No. 55-38483, Japanese Patent Application Laid-Open No. 53-89360, U.S. Pat.
No. 86, U.S. Pat. No. 4,143,298, and the like.

In addition, in order to improve the focus characteristics and obtain a high-performance cathode ray tube, it is necessary to increase the voltage applied to the focus electrode. If the voltage is higher than the medium voltage applied to the electrode, beam leakage from the low voltage application electrode is likely to occur. Therefore, the first electrode which surrounds the insulating support portion facing the focus electrode and is conductively connected to the focus electrode is used. Forming a second metal deposition film on the inner surface of the neck facing the metal deposition film and the first metal deposition film,
Means for preventing the beam leakage is disclosed in Japanese Patent Application Laid-Open No. 56-123.
No. 651.

FIG. 2 shows a main structure of a high-performance color picture tube provided with the above-mentioned resistor and beam leakage preventing means.
In this color picture tube, the electron gun 5 has a cathode K, and first to tenth grids G1 to G10 which are sequentially arranged on the cathode K at predetermined intervals in the phosphor screen direction. And a convergence cup C is attached to the tenth grid G10. A resistor 15 is arranged on a surface of the pair of insulating supports 14 facing one neck 3. Further, a metal ring 16 is attached to a seventh grid G7 (focus electrode) to which a medium voltage is applied.
The portion of the insulating support 14 facing the grid G7 and the resistor 15
A first metal deposited film 17 surrounding and electrically connected to the seventh grid G7, and a second metal deposited film 18 is formed on the inner surface of the neck 3 in opposition to the first metal deposited film 17.

By the way, a cathode ray tube to which a higher voltage is applied than before is subjected to a withstand voltage treatment after exhausting the tube in a manufacturing process so as to obtain required withstand voltage characteristics. As the withstand voltage processing method, in a color picture tube, any combination of the four types of processing methods (processing (I) to processing (IV)) shown in Table 1 is performed. In particular, as described above, the first and second processing methods are used. In the color picture tube on which the metal deposition films 17 and 18 are formed, withstand voltage processing is performed after the formation of the first and second metal deposition films 17 and 18.

[0009]

[0010] In Table 1, AD is shown in FIG.
Connection terminal A of the equivalent circuit shown in FIG.
~ D.

In Table 1, treatment (I) is performed by using a resistor 15
Of the anode terminal A, that is, the terminal 20 on the tenth grid G10 side of the resistor 15 and the tenth grid G10 are connected to the anode terminal A at about 80 kV, which is about 2-3 times the normal operating voltage.
This is a process performed by applying a pulse voltage having a peak voltage of. Also, treatments (II) and (III)
Is performed by applying a pulse voltage having a peak voltage of about 60 kV, which is about 1.5 to 2 times the normal operating voltage, to the anode terminal A by grounding the cathode side end D. Further, in the process (IV), the anode terminal A is released, and the connection terminal B, that is, the third, fifth, and seventh grids G3, G5, and G7, is applied with a voltage of about 15 kV, which is about 1.5 to 2 times the normal operating voltage. This is a process performed by applying a pulse voltage having a peak voltage of. In addition,
In these processes (I) to (IV), the other connection terminals are grounded.

However, when the color cathode ray tube on which the first and second metal deposition films 17 and 18 are formed is processed by the above-described withstand voltage processing method, when the processing is performed by the processings (I) to (III),
The metal ring 16 attached to the seventh grid G7, or the first metal deposition film 17 surrounding the portion of the insulating support body 14 facing the seventh grid G7 and conductively connected to the seventh grid G7.
A sharp creeping discharge is generated around the connection terminal 21 for applying a medium voltage different from the medium voltage of the seventh grid G7 to the ninth grid of the resistor 15 via the A phenomenon occurs in which the wiring extends to the periphery of the high-voltage application connection terminal 20.

When such a creeping discharge occurs, the resistor 15 is usually formed in a structure in which a resistance pattern is formed on a ceramic insulating substrate and the resistance pattern is covered with an insulating coating such as glass. At the weak point of the insulating coating between the first metal deposition film 17 and the ninth grid connection terminal 21 formed on the insulating coating, a through dielectric breakdown reaching the resistance pattern thereunder occurs, and the resistance of the resistor 15 is reduced. The value changes, and a strip of the insulating coating caused by the above-mentioned through dielectric breakdown or dielectric breakdown due to creeping discharge adheres to the shadow mask 6 to cause a non-light emitting portion on the phosphor screen 2 or an electron gun. Thus, problems such as deterioration of the withstand voltage characteristics due to adhesion to the electrode No. 5 occur.

Conventionally, in order to prevent such a deterioration of the resistor 15 and a deterioration of the withstand voltage characteristic, the applied voltage at the time of the withstand voltage processing is reduced and the processing is performed. However, there is a problem that a sufficient discharge cannot be generated in a portion that originally requires withstand voltage processing, and therefore, it is difficult to obtain a required withstand voltage characteristic.

[0015]

As described above, conventionally, a plurality of electrodes of an electron gun are supplied from the anode terminal to the high voltage application electrode of the electron gun on the surface of the insulating support body facing the neck, which integrally fixes the electrodes. A resistor for dividing a high voltage applied to the medium voltage application electrode to a medium voltage is arranged, a metal ring is attached to the medium voltage application electrode, and the insulating support portion and the resistor facing the medium voltage application electrode are attached. There is a first metallized film electrically conductively connected to the middle voltage application electrode, and a color picture tube for forming a second metallized film on the inner surface of the neck facing the first metallized film.

As a withstand voltage treatment method for this color picture tube, if a withstand voltage treatment shown in Table 1 is performed after the formation of the first and second metal deposition films, a high voltage is applied particularly to the anode terminal. Processing (I) to Processing (I)
In the case of II), a vigorous creeping discharge is generated around the connection terminal of the resistor with the middle voltage application electrode through the metal ring or the first metal deposition film, and the creeping discharge is applied to the high voltage of the resistor. The phenomenon that the terminal extends to the peripheral portion occurs. And for such a creeping discharge, the insulating coating covering the resistor pattern of the resistor is destroyed, and the breakdown reaches the resistor pattern below it, changing the resistance value,
The delamination of insulation coating caused by dielectric breakdown adheres to the shadow mask, causing non-light-emitting areas on the phosphor screen, or causing problems such as deterioration of withstand voltage characteristics due to adhesion to the electrode of the electron gun. I do.

In order to prevent such deterioration of the resistor and the withstand voltage characteristics, if the applied voltage at the time of the withstand voltage process is reduced, a sufficient discharge is generated in a portion which originally requires the withstand voltage process. Therefore, there is a problem that it is difficult to obtain required withstand voltage characteristics.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a structure in which a plurality of electrodes of an electron gun are integrally fixed to a neck-facing surface of an insulating support. A resistor for dividing the high voltage supplied to the electron gun into a medium voltage applied to the medium voltage application electrode is placed, and a metal ring is attached to the medium voltage application electrode, and the insulation facing the medium voltage application electrode is attached. A first metallized film surrounding a support portion and a resistor and conductively connected to a middle voltage application electrode, and a cathode ray tube forming a second metallized film on an inner surface of a neck opposed to the first metallized film Another object of the present invention is to provide a withstand voltage processing method capable of obtaining sufficient withstand voltage characteristics without deteriorating a resistor.

[Structure of the Invention]

[0020]

SUMMARY OF THE INVENTION A low voltage application electrode for controlling electron emission from a cathode and converging the emitted electrons to form an electron beam, and accelerating and focusing this electron beam toward a phosphor screen. An electron gun having a middle and high voltage application electrode and having a plurality of these electrodes integrally fixed by an insulating support is disposed in the neck, and is applied to the high voltage application electrode on the neck facing surface of the insulating support. A resistor for dividing a high voltage applied to the medium voltage application electrode into a medium voltage for application to the medium voltage application electrode is arranged, and the medium voltage application electrode surrounds the insulating support and the resistor and is electrically connected to the medium voltage application electrode. And a metal ring for forming a second metal deposition film on the inner surface of the neck corresponding to the first metal deposition film. In the method for withstanding voltage treatment of a cathode ray tube for applying a withstand voltage by applying a high voltage to the resistor, at least the high voltage application may be performed before evaporating the metal ring to form the first and second metal deposition films. After applying a high voltage to the electrode and the resistor to withstand voltage, evaporating the metal ring to form the first and second metal deposition films, at least applying the high voltage to the electrode and the resistor A high voltage was applied to perform the withstand voltage process again.

[0021]

As described above, when the withstand voltage treatment is performed separately before and after the formation of the metal vapor deposition film, before the formation of the metal vapor deposition film,
The relatively high applied voltage can sufficiently process the parts that originally require withstand voltage processing.After the metal deposition film is formed, the relatively low applied voltage allows the metal deposition without destruction of the resistor. Harmful and unnecessary portions with respect to withstand voltage formed by the film can be removed, and as a result, a cathode ray tube having sufficient withstand voltage characteristics can be obtained.

[0022]

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

FIG. 1 shows an arrangement of an electron gun, a resistor, and the like, which are main components of a color picture tube according to an embodiment of the present invention. The electron gun 5 includes three cathodes K, three heaters H for heating the cathodes K, and first to tenth cathodes arranged adjacent to the cathodes K at predetermined intervals in the direction of the phosphor screen.
A plurality of electrodes such as the cathode K, the heater H, and the grids G1 to G10 are integrally fixed by a pair of insulating supports 14, and the tenth grid G10 is provided.
And a convergence cup C is attached to the rim. The second grid G2 and the fourth grid G4, the third grid G3, the fifth grid G5, the seventh grid G7, and the sixth grid G7.
The grid G6 and the eighth grid G8 are connected at the same potential.

In the electron gun 5 having this structure, the first to third grids G1 to G3 adjacent to the cathode K control the emission of electrons from the cathode K, and focus the emitted electrons into an electron beam. A beam forming part is formed, and the third to tenth grids G3 to G10 form an electron lens for accelerating and focusing the electron beam extracted from the electron beam forming part toward the phosphor screen.

With respect to the electron gun 5, a resistor 15 is arranged on a surface of one of the insulating supports 14 facing the neck 3 fixing the above-mentioned electrodes. This resistor 15 forms a resistance pattern on one surface of an elongated ceramic insulating substrate,
The resistance pattern is formed in a structure in which the resistance pattern is covered with an insulating coating made of glass. One end thereof is connected to the convergence cup C via the connection terminal 20, and the other end thereof is connected to the stem pin 12 of the stem 11 which seals the end of the neck 3.
Via a ground, or even a variable resistor (not shown)
, And the intermediate portion is connected to the sixth and ninth grids G6, G9 via connection terminals 23, 21, respectively.

Due to the disposition of the resistor 15, the tenth grid G10 of the electron gun 5 is attached to the anode terminal provided on the cone portion, the internal conductive film 10, and the convergence cup C to be connected to the internal conductive film 10. A relatively high voltage is applied via the plurality of valve spacers 25 and the convergence cup C which are pressed against each other, and the sixth grid G6, the eighth grid G8 connected to the sixth grid G6 at the same potential, and the ninth grid G6. A predetermined medium voltage obtained by dividing the anode high voltage supplied to the convergence cup C by the resistor 15 is applied to the grid G9. A relatively low voltage is applied to the other electrodes via the stem pins 12 of the stem 11.

The voltage is divided by the resistor 15 so that the sixth and eighth
The medium voltage supplied to the grids G6, G8 and the ninth grid G9 is, for example, 4% of the anode high voltage during the operation of the color picture tube.
0% and 65%.
3, R1 is the resistance value from the connection terminal 20 at one end to the intermediate connection terminal 21, R2 is the resistance value from the connection terminal 21 to the other intermediate connection terminal 23, as shown in FIG. Assuming that the resistance value from the connection terminal 23 to the other end grounding portion is R3, when the total resistance value is 2000 MΩ, the resistance is divided so that R1 = 700 MΩ R2 = 500 MΩ R3 = 800 MΩ.

Further, in this color picture tube, a portion of the insulating support 14 facing the seventh grid G7 and one of the insulating supports are provided on the seventh grid G7 of the electron gun 5.
A metal ring 16 surrounding a resistor 15 arranged on the 14 neck facing surface is attached. This metal ring 16 is shown in FIG.
As shown in FIG. 7, after the pipe is evacuated, the first metal deposition film surrounding the portion of the insulating support body 14 facing the seventh grid G7 and the resistor 15 disposed on the neck-facing surface of the one insulating support body 14 17 and a neck 3 facing the first metal deposition film 17
This is for forming the second metal deposition film 18 on the inner surface.

The withstand voltage processing of the color picture tube is performed in two stages. First, as shown in Table 1, before the tube was evacuated and before the metal ring 14 attached to the seventh grid G7 was evaporated to form the first and second metal deposition films 17 and 18, Processing method, that is, processing (I)
Or any combination of the processing (IV), the distance between the inner surface of the neck 3 and the resistor 15, the distance between the inner surface of the neck 3 and the insulating support 14, the distance between the insulating support 14 and the resistor 15, the fifth grid G5 Or first
Among the 0 grid G10 and the like, the high voltage application electrodes and the low and medium voltage application electrodes such as the first to fifth grids G1 to G5 are selectively processed.

Next, the metal ring 16 attached to the seventh grid G7 is heated and evaporated from the outside of the neck 3 by high-frequency induction heating, and the portion of the insulating support body 14 facing the seventh grid G7 and one of the insulating members are insulated. A first metallized film 17 surrounding the resistor 15 disposed on the neck-facing surface of the support 12 and conductively connected to the seventh grid G7, and a second metallized film on the inner surface of the neck 3 opposed to the first metallized film 17 A metal deposition film 18 is formed.

Thereafter, as a second stage, the processing is performed again by an arbitrary combination of the processing (I) to the processing (III) among the processing methods shown in Table 1.

By the way, if the withstand voltage treatment is performed in two stages before and after the formation of the first and second metal vapor-deposited films 17 and 18 as described above, damage to the resistor 15 which has conventionally occurred and damage to the resistor 15 may occur. It is possible to provide a color picture tube which prevents deterioration and has good withstand voltage characteristics. That is, as described above, the two metallization films 17 and 18 before and after the formation of the first and second metal deposition films 17 and 18 are interposed therebetween.
When the withstand voltage processing is performed in steps, the first processing is performed between the inner surface of the neck 3 and the resistor 15, between the inner surface of the neck 3 and the insulating support 14, and between the insulating support 14 and the resistor 15. Between the high voltage application electrodes, between the fifth grid G5 to the tenth grid G10, between the high voltage application electrodes, between the low and medium voltage application electrodes such as the first grid G1 to the fifth grid G5, etc. The withstand voltage processing portion can be processed under relatively strong processing conditions like a normal color picture tube. Therefore, in the subsequent processing, it is only necessary to remove the harmful and unnecessary deposited film on the withstand voltage characteristic generated by the formation of the first and second metal deposited films 17 and 18, and to process under relatively weak processing conditions. Conventionally, it is possible to prevent the resistor 15 from being damaged or deteriorated by the creeping discharge generated via the metal deposition film 17, and to remove a harmful and unnecessary deposition film with respect to its withstand voltage characteristic. A color picture tube having characteristics can be obtained.

Table 2 shows an example of the above-described withstand voltage processing method in comparison with a conventional withstand voltage processing method.

[0034]

Table 2 shows that the withstand voltage treatment, which was conventionally performed in the treatment 1 and the treatment time T, is particularly performed in the first stage treatment before the formation of the metal vapor deposition film in the treatment II in the treatment time 0.75T. In the second stage processing after forming the metal deposition film, the processing (III) and the processing (I) in which the applied voltage is reduced to 70%
V) is 0.25T, and the withstand voltage processing is the same as the conventional processing time.

When the withstand voltage treatment is performed by such a method, damage and deterioration of the resistor can be eliminated, and the withstand voltage characteristics can be improved by about 10% as compared with the conventional withstand voltage treatment method.

[0037]

According to the present invention, a resistor for dividing a high voltage applied to a high voltage applying electrode into a medium voltage applied to a medium voltage applying electrode is provided on the neck-facing surface of an insulating support for integrally fixing a plurality of electrodes of the electron gun. A first metal deposition film surrounding the insulating support and the resistor around the middle voltage application electrode and electrically conductively connecting to the middle voltage application electrode; and a first metal deposition film corresponding to the first metal deposition film. Before evaporating the metal ring to form the first and second metal vapor-deposited films on the cathode ray tube in which the metal ring forming the second metal vapor-deposited film is disposed on the inner surface of the neck, at least the high voltage After applying a high voltage to the application electrode and the resistor to withstand a voltage and evaporating the metal ring to form the first and second metal deposition films, at least the high voltage application electrode and the resistor Apply high voltage to When the withstand voltage process is performed again, by increasing the applied voltage before forming the first and second metal vapor-deposited films to a relatively high level, it is possible to sufficiently treat the portion that originally requires the withstand voltage process, After the formation, the applied voltage is relatively low, and without damaging or deteriorating the resistor, it is possible to remove the harmful portion in the withstand voltage formed by the metal deposited film, and as a result, sufficient A cathode ray tube having withstand voltage characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main configuration of a color picture tube for describing a withstand voltage processing method according to an embodiment of the present invention.

FIG. 2 is a view for explaining a withstand voltage treatment method after the formation of a metal deposition film.

3 is an equivalent circuit diagram of the electron gun of the color picture tube shown in FIG.

FIG. 4 is a diagram showing a configuration of a color picture tube.

[Explanation of symbols]

 3: Neck 5: Electron gun 14: Insulating support 15: Resistor 16: Metal ring 17: First metal deposition film 18: Second metal deposition film 20: Connection terminal 21: Connection terminal 23: Connection terminal C: Convergence Cup G1 ... First grid G2 ... Second grid G3 ... Third grid G4 ... Fourth grid G5 ... Fifth grid G6 ... Sixth grid G7 ... Seventh grid G8 ... Eighth grid G9 ... Ninth grid G10 ... Tenth Grid H: heater K: cathode

Claims (1)

(57) [Claims] 1. A low-voltage application electrode for controlling electron emission from a cathode and converging the emitted electrons to form an electron beam, and a high voltage while accelerating and converging the electron beam toward a phosphor screen. An electron gun having an application electrode and having a plurality of these electrodes integrally fixed by an insulating support is disposed in the neck, and a high voltage applied to the high voltage applying electrode is applied to the neck facing surface of the insulating support. A first metal that is arranged with a resistor that divides the voltage into a medium voltage applied to the medium voltage application electrode, and that surrounds the insulating support and the resistor around the medium voltage application electrode and is conductively connected to the medium voltage application electrode; At least the high voltage application electrode and the resistor are high with respect to a cathode ray tube in which a metal ring for forming a second metal deposition film on the inner surface of the neck corresponding to the first metal deposition film is disposed. In a withstand voltage processing method for a cathode ray tube which applies a voltage to withstand a voltage, before evaporating the metal ring to form the first and second metal deposition films,
After applying a high voltage to at least the high voltage application electrode and the resistor to withstand voltage, evaporating the metal ring to form the first and second metal deposition films, at least the high voltage application electrode And applying a high voltage to the resistor to perform a withstand voltage process again.