JPH05283005A - Withstand voltage processing method of cathode ray tube - Google Patents

Abstract

PURPOSE:To increase withstand voltage and at the same time, breakdown volt age of neck penetration breakdown. CONSTITUTION:In the withstand voltage processing method of a cathode ray tube, a high voltage which is relatively higher than a voltage impressed on electrodes G1-G5 other than high voltage electrodes G6, CO of an electron gun is applied to the high voltage electrodes G6, CO is applied to the electrodes G6, GO,through the inside conductive film 10 from an anode terminal and the bulb spacer 21 pressure-welded to the terminal so that a withstand voltage process is performed. Then, a DC or an AC voltage which is relatively higher than the voltage applied to the high voltage electrode or DC or AC pulse voltage is applied to the other electrodes G1-G5 of the electron gun in the middle of that withstand voltage process so that a process to generate discharge at the end portion of the neck of the inside conductive film is performed.

Description

Detailed Description 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.

[0002]

2. Description of the Related Art Generally, a cathode ray tube is constructed as shown in FIG.
Phosphor screen on the inner surface of the faceplate 1 of the envelope
2 is formed, and this phosphor screen 2 is emitted from the electron gun 4 arranged in the neck 3 of the envelope.
It is formed into a structure for displaying an image by scanning with 5. In particular, for a color picture tube, a shadow mask 6 is attached to the inside of the phosphor screen 2 so as to face the phosphor screen 2, and the shadow mask 6 selects the 3 electron beams 5 emitted from the electron gun 4 to select the phosphor screen 2. It is formed in such a structure that it is made incident on the constituent three-color phosphor layer.

The electron gun 4 generally controls the emission of electrons from the cathode, and forms a electron beam forming unit for accelerating and focusing the emitted electrons to form an electron beam. And a plurality of electrodes that form an electron lens such as a main electron lens that extracts an electron beam from the electron beam forming unit and accelerates and focuses the extracted electron beam on the phosphor screen 2. The electrodes are formed in a structure integrally fixed by an insulating support. Among these electrodes, a relatively low predetermined low voltage is applied to the electrode forming the electron beam forming portion, and a relatively high medium voltage is applied to the plurality of electrodes forming the main electron lens and the like. Is applied. In particular, the final accelerating electrode forming the main electron lens is connected to the cone terminal 8 of the envelope from the anode terminal 9
The high voltage of the anode is applied through the inner conductive film 10 coated on the inner surface of 8 and other low and medium voltage electrodes are applied to the electrodes of the neck 3 where the electron gun 4 is arranged. A predetermined low and medium voltage is applied via a plurality of stem pins 12 that hermetically penetrate the stem 11 that seals the.

Such a cathode ray tube is, for example, for a color picture tube, a face plate 1 (usually called a panel in a color picture tube) having a phosphor screen 2 formed on the inner surface and a shadow mask 6 mounted on the inner surface. A cone 8 (usually called a funnel in a color picture tube) coated with an inner conductive film 10 is sealed to form an envelope, and then an electron gun 4 is sealed in the neck 3 of this envelope. Then, it is evacuated, and thereafter, it is manufactured by subjecting the cathode to activation treatment, withstand voltage treatment and the like.

By the way, the voltage applied to the anode terminal of the conventional color picture tube is about 20 to 30 kV.
In order to improve the brightness of the screen, the voltage applied to the anode terminal tends to be higher, and accordingly, a higher withstand voltage is being demanded. Therefore, in the withstand voltage treatment in the manufacturing process of the color picture tube, the required withstand voltage is dealt with by strengthening the withstand voltage treatment such as increasing the treatment voltage or prolonging the treatment time.

However, when the voltage treatment is strengthened as described above, at the time of the treatment, a spark discharge is generated in the vicinity of the neck side end portion of the inner conductive film 10 formed on the inner surface of the neck 3 to cause neck 3
Dielectric breakdown that penetrates through (neck through dielectric breakdown) occurs at a higher rate than in the conventional withstand voltage treatment. In particular, this breakdown through the neck occurs remarkably when the outside air has a high humidity.

Conventionally, as a method for increasing the breakdown voltage of the through-the-neck breakdown that occurs near the end portion on the neck side, a DC voltage is applied with the anode terminal as the cathode side and the stem pin as the anode side before or after the withstand voltage treatment. In order to condition the end portion of the inner conductive film 10 on the neck side, Japanese Patent Publication No.
-19060 gazette.

According to this method, it is possible to increase the breakdown voltage of the dielectric breakdown through the neck. However, if this process is performed before the withstand voltage process, for example, the voltage applied at this time causes the electrode (high voltage electrode) to which the high voltage of the electron gun is applied and the electrode (medium voltage electrode) to which the medium voltage is applied. Since the treatment between the electrodes is also performed and the withstand voltage of these electrode portions is improved, the discharge voltage between the high-voltage electrode and the medium-voltage electrode during the withstand voltage treatment that is performed following the conditioning of the neck side end, Higher than without conditioning the neck end. As a result, in the withstand voltage treatment schedule of Table 1 that is generally performed, when the treatment [II] is performed, a high voltage is applied between the high-voltage electrode and the medium-voltage electrode, and the withstand voltage treatment socket. A problem of accelerating the deterioration of.

[0009]

[Table 1] In Table 1, A is a connection terminal connected to the high voltage electrode, B is a connection terminal connected to the medium voltage electrode, and C is a connection terminal connected to an electrode to which a relatively low voltage is applied. is there.

Further, when the end portion on the neck side is conditioned after the withstand voltage treatment, in this case, spark discharge is generated from the end portion on the neck side, and carbon fine particles, water glass fine particles, etc., which are components of the inner conductive film, are scattered and electrons are emitted. It adheres to the gun electrode and deteriorates from the withstand voltage quality before conditioning (after withstanding voltage treatment). That is, FIG. 3 shows the withstand voltage b1 when treated according to the withstand voltage treatment schedule of Table 1, and Table 1
After performing the withstand voltage treatment schedule of, the withstand voltage when the neck side end is further conditioned
As shown as b2, the withstand voltage quality deteriorates significantly.

[0011]

As described above, in a cathode ray tube, for example, a color picture tube, a phosphor screen is formed on the inner surface and a shadow mask is attached to the inside of the face plate, and an inner surface is electrically conductive. After forming the envelope by sealing the cone portion with the film formed by coating, the electron gun is sealed in the neck of the envelope and exhausted,
Then, it is manufactured by subjecting the cathode to activation treatment and withstand voltage treatment.

[0012] As a method for processing the withstand voltage, the conventional method is shown in Table 1.
Although it was processed according to the withstand voltage processing schedule shown in, the withstanding voltage such as increasing the processing voltage or increasing the processing time is taken in response to the higher voltage applied to the anode terminal for improving the brightness of the screen. When the voltage treatment is strengthened, at the time of the withstand voltage treatment, a high rate of dielectric breakdown occurs through the neck due to spark discharge in the vicinity of the neck side end of the inner conductive film formed on the neck inner surface.

Conventionally, as a method of increasing the breakdown voltage of this through-the-neck breakdown, a DC voltage is applied with the anode terminal as the cathode side and the stem pin as the anode side before or after the withstand voltage treatment, and the neck side end of the inner conductive film is applied. Methods of conditioning the department are known.

According to this method, however, for example, when the end portion on the neck side is conditioned before the withstand voltage treatment, the voltage applied at this time also performs the treatment between the high voltage electrode and the medium voltage electrode of the electron gun. The withstand voltage of the electrode part is also slightly improved. Therefore, during the withstand voltage treatment performed after the conditioning of the neck side end portion, the discharge voltage between the high-voltage electrode and the medium-voltage electrode becomes high, which causes a problem of accelerating the deterioration of the withstand voltage treatment socket. In addition, if the end on the neck side is conditioned after the withstand voltage treatment, in this case, a spark discharge is generated from the end on the neck side, and carbon fine particles or water glass fine particles, which are components of the inner surface conductive film, are scattered and the electrode of the electron gun is Attached to the
There is a problem that the withstand voltage is significantly deteriorated as compared with the withstand voltage quality after the withstand voltage treatment.

The present invention has been made in view of the above problems, and an object thereof is to obtain a withstand voltage treatment method for a cathode ray tube capable of increasing the withstand voltage and, at the same time, the breakdown voltage of the through-the-neck breakdown. To do.

[0016]

SUMMARY OF THE INVENTION An anode terminal provided in an envelope, an electron gun having a plurality of electrodes arranged in a neck of the envelope, and a height of the electron gun connected to the anode terminal. A cathode-ray tube having an inner conductive film formed on the inner surface of the envelope with the end facing the voltage electrode on the neck side and having a valve spacer pressed against the inner conductive film attached to the electron gun. In the treatment method, a high voltage relatively higher than a voltage applied to the high voltage electrode of the electron gun from the anode terminal to the other electrode of the electron gun is applied through the inner conductive film and the valve spacer pressed against the inner conductive film. During the voltage treatment, a DC or AC pulse voltage or a DC or AC pulse voltage that is relatively higher than the voltage applied to the high voltage electrode of the electron gun is applied to the other electrodes of the electron gun during this withstand voltage treatment. And then conductive inside And to perform a process of generating a discharge in the neck end.

[0017]

As described above, a relatively high voltage is applied to the high voltage electrode of the electron gun, which is higher than the voltage applied from the anode terminal to the other electrode of the electron gun through the inner conductive film and the valve spacer pressed against the inner conductive film. When applying voltage to withstand voltage,
During this withstand voltage treatment, a DC or AC voltage or a DC or AC pulse voltage, which is relatively higher than the voltage applied to the high voltage electrode of the electron gun, is applied to the other electrode of the electron gun to apply the inner conductive film. By performing a process for generating a discharge at the neck end of the, the breakdown voltage and the breakdown voltage of the through-the-neck breakdown can be increased.

[0018]

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

FIG. 1 shows an electron gun of a color picture tube according to the embodiment, and FIG. 2 shows an equivalent circuit thereof. This electron gun has three cathodes K, three heaters H for individually heating the cathodes K, and first to first electrodes sequentially arranged on the cathode K at a predetermined interval in the phosphor screen direction. Has 6 grids G1 to G6, these cathodes K, heater
H and the grids G1 to G6 are integrally fixed by a pair of insulating supports 20, and a convergence cup CO is attached to the tip end side of the sixth grid G6.

The second grid G2 and the fourth grid G4,
The third grid G3 and the fifth grid G5 are connected to the same potential in the tube. Convergence
On the outer surface of the cup CO, a plurality of valve spacers 21 are attached which are in pressure contact with the inner conductive film 10 formed by coating from the cone portion 8 to the inner surface of the adjacent portion of the neck 3 facing the convergence cup CO. In FIG. 1, 11 is a stem and 12 is a stem pin.

In this electron gun, the cathode K, the heater H, and the first, second, and fourth grids G1, G2, and G4 have necks.
3 Stem pin that hermetically penetrates the stem 11 that seals the end
A relatively low predetermined low voltage is applied via 12 to the third and fifth grids G3, G5, and a predetermined medium voltage is also applied via the stem pin 12. Also the 6th grid G6
A relatively high predetermined high voltage is applied to the convergence cup CO from the anode terminal provided in the cone portion 8 via the inner conductive film 10 and the valve spacer 21.

By applying this voltage, in this electron gun, the electron emission from the cathode K is controlled by the cathode K and the first to third grids G1 to G3, and the emitted electrons are focused into an electron beam. An electron beam forming unit is formed, and an electron lens for extracting the electron beam from the electron beam forming unit and accelerating and focusing the electron beam on the phosphor screen is formed by the third to sixth grids G3 to G6.

As shown in FIG. 2, the withstand voltage processing of the color picture tube provided with such an electron gun is carried out as shown in FIG. 2 by the terminal A, the third and fifth grids G3 connected to the sixth grid G6 and the convergence cup CO. , B5 connected to G5, second and fourth grids G2 and G4 and cathode K, and terminal C connected to heater H are connected to the withstand voltage processing circuit, respectively, and opened to each terminal A, B, C. By applying a predetermined voltage including grounding, the operation is performed in the following three stages.

First, as a first step, with respect to the color picture tube after exhaustion, according to the conventional withstand voltage processing schedule shown in Table 1, any combination of processing [I], processing [II] and processing [III] is performed. Accordingly, between the inner surface of the neck 3 and the insulating support 20, between the fifth grid G5 and the sixth grid G6, that is, between the medium voltage electrode and the high voltage electrode, the first grid G1 to the fifth grid G5 The low and medium voltage electrodes are selectively processed.

Next, in the second step, by the treatment method shown in Table 2, the sixth grid G6, which is a high voltage electrode, is set to the cathode side (ground), and the other low and medium voltage electrodes are set to the anode side (high voltage is applied). As a result, a high voltage of direct current or direct current pulse is applied to the anode side to condition the end portion of the inner conductive film 10 on the neck side.

[0026]

[Table 2] After that, as a third step, a higher voltage than that of the first step is applied by an arbitrary combination of the processing [I], the processing [II], and the processing [III] of the conventional withstand voltage processing schedule shown in Table 1. Apply and process.

As described above, the withstand voltage treatment is divided into three steps, and if the conditioning treatment of the end portion on the neck side of the inner conductive film 10 is performed during the withstand voltage treatment, the neck of the inner conductive film 10 is discharged due to the discharge generated at this time. A cathode spot is generated at the side edge, and the neck side edge of the inner surface conductive film 10 is smoothed. As a result, it is possible to prevent the through-neck breakdown of the neck that has occurred near the end portion on the neck side of the inner conductive film 10 during the conventional withstand voltage treatment. Further, by this conditioning treatment, the breakdown voltage of the through-the-neck dielectric breakdown rises, and the applied voltage of the withstand voltage treatment of the third stage performed after this conditioning treatment can be made higher than the applied voltage of the conventional withstand voltage treatment, As a result, a color picture tube having good withstand voltage characteristics can be obtained.

FIG. 3 shows a withstand voltage of a1 when only the above-mentioned first step is performed, and a2 of further withstand voltage when the second step is performed after this first step. The withstand voltage when the third step is performed after the second step is a3, and the withstand voltage when the first step is performed is b1 as a comparative example. When the second step is performed after the first step is performed after the second step is performed as shown by the withstand voltage b2 when the second step is performed after the treatment, the withstand voltage temporarily decreases. By performing the third stage process, the withstand voltage can be significantly improved as compared with the withstand voltage when only the first stage process is performed.

In the above embodiment, when conditioning the neck side end of the inner conductive film, a high voltage of direct current or direct current pulse was applied to the anode side of the inner conductive film. A high voltage of AC pulse may be used.

When a high voltage of alternating current or alternating current pulse is applied to the anode side as described above, when the anode side has a relatively negative voltage, a red or red spark discharge is generated from the end of the inner conductive film on the neck side. The spark discharge is generated and the end portion on the neck side can be smoothed, and the same effect as that of the above-described embodiment can be obtained.

Further, in the above embodiment, as the first withstand voltage treatment, any combination of the process [I], the process [II] and the process [III] of the conventional withstand voltage treatment schedule shown in Table 1 is used. After the so-called low electrode treatment of treatment [I] of the withstanding voltage treatment schedule shown in Table 1, each terminal was
The polarity of the voltage applied to A, B, and C is reversed, and the terminal C connected to the second and fourth grids and the low-voltage electrodes of the cathode and heater is the anode side, and the terminal connected to the other electrodes. If A and B are set to the cathode side (ground) and the process [VI] shown in Table 3 is performed, even if the conventional withstand voltage process is performed,
It is possible to significantly improve the low voltage electrode having poor withstand voltage quality.

[0032]

[Table 3] In addition, since this treatment [VI] is performed in a state where the fifth and sixth grids and the inner conductive film are kept at the same potential, conditioning of the end portion on the neck side of the inner conductive film is not performed, and the inner conductive film is not processed. There is no scattering of component particles from. Therefore, in this treatment [VI], the withstand voltage treatment may be performed at any time during the treatment, and as a result, the withstand voltage quality of the low-voltage electrode can be improved.

Table 4 shows that as the first stage process, the above process [VI] is inserted after the process [I] of the conventional withstand voltage process schedule shown in Table 1, and then the second stage process is performed.
This is an example of the case where the neck side end portion of the inner conductive film is conditioned, and then the processing [II] and the processing [III] are performed as the third stage processing. When the withstand voltage treatment is performed according to such a schedule, the withstand voltage treatment is performed in the order of treatment II], treatment [II], and treatment [III] by the conventional withstand voltage treatment method shown in Table 4 as a comparative example. In this case, with respect to the neck penetrating breakdown that occurred during the withstand voltage treatment, the neck penetrating fracture during the withstand voltage treatment could be reduced to 5% or less, and the withstand voltage characteristics could be improved by about 10%.

[0034]

[Table 4] Although each of the above embodiments has been described with respect to the color picture tube, the present invention can be applied to a cathode ray tube other than the color picture tube.

[0035]

The high voltage electrode of the electron gun is applied with a relatively high voltage higher than the voltage applied from the anode terminal to the other electrode of the electron gun through the inner conductive film and the valve spacer pressed against the inner conductive film. During the withstand voltage treatment, a DC or AC pulse voltage or a DC or AC pulse voltage that is relatively higher than the voltage applied to the high voltage electrode of the electron gun is applied to the other electrodes of the electron gun during this withstand voltage treatment. When applied and subjected to a treatment to generate a discharge at the neck end of the inner conductive film, the withstand voltage can be increased, and at the same time, the breakdown voltage of the through-the-neck breakdown can be increased, and a cathode ray tube having good withstand voltage characteristics can be obtained. be able to.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the structure of an electron gun of a color picture tube according to an embodiment of the present invention.

FIG. 2 is a diagram showing an equivalent circuit of the electron gun.

FIG. 3 is a diagram showing an effect obtained by performing a certain withstand voltage treatment according to an embodiment of the present invention in comparison with a case of performing a conventional withstand voltage treatment.

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

[Explanation of symbols]

 3 ... Neck 8 ... Cone 10 ... Inner conductive film 12 ... Stem pin 20 ... Insulating support 21 ... Valve spacer A ... Terminal B ... Terminal C ... Terminal CO ... Convergence cup G1 ... First grid G2 ... Second grid G3 ... 3rd grid G4 ... 4th grid G5 ... 5th grid G6 ... 6th grid H ... Heater K ... Cathode

Claims (1)

[Claims] 1. An anode terminal provided in an envelope, an electron gun including a plurality of electrodes arranged in a neck of the envelope, and a high voltage of the electron gun connected to the anode terminal. A cathode ray tube having an inner conductive film formed on the inner surface of the envelope with the position facing the electrode as the neck side end, and a valve spacer press-contacting the inner conductive film is attached to the electron gun, A high voltage is applied to the high voltage electrode of the electron gun, which is relatively higher than the voltage applied from the anode terminal to the other electrode of the electron gun through the inner conductive film and the valve spacer pressed against the inner conductive film. In performing the voltage processing, a DC or AC voltage, or a DC or AC pulse voltage, which is relatively higher than the voltage applied to the high voltage electrode of the electron gun in the other electrode of the electron gun during the withstand voltage processing. Apply And a withstand voltage treatment method for a cathode ray tube, characterized in that a treatment for generating an electric discharge is performed at a neck end portion of the inner surface conductive film.