JP2004095284A - Cathode-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cathode-ray tube improved in voltage resistance characteristics by preventing an insulation breakdown of the resistor, although the potential in the neck inner wall is made lowered by forming a metallic vapor deposition membrane on the neck inner wall and the surface of the partial pressure resistor by arranging a metallic ring on the electron gun in the cathode-ray tube neck and by heating this metallic ring, this metallic ring contacts the resistor and glow discharge is generated by the AC high voltage impressed at the voltage-resistant treatment, and thereby, the resistor has suffered insulation breakdown. <P>SOLUTION: Each grid electrode G1 to G8 which constitutes an electron gun 21 installed in a cathode-ray tube neck 19 is supported by an insulating support 23, and a metallic ring 29 is provided with a prescribed spacing L so as to surround a resistor 24 which supplies a partial voltage to this insulating support 23 and the prescribed grid electrodes. This spacing L is established as 0.005 mm ≤ L ≤ 2.0 mm. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cathode ray tube used for a color television receiver and the like, and more particularly to a cathode ray tube in which a metal ring of an electron gun structure is heated to form a metal deposition film on an inner wall of a neck and a surface of a resistor.
[0002]
[Prior art]
At present, as shown in FIG. 7, a color cathode ray tube used in a general color television receiver or the like includes a face panel 61 having a substantially rectangular shape, and a funnel integrally joined to the face panel 61. A phosphor screen 63 formed of a striped or dot-shaped three-color phosphor layer that emits blue, green, and red light is formed on the inner surface of the face panel 61; Opposite to the phosphor screen 63, a shadow mask 64 having a large number of apertures formed therein is mounted.
[0003]
On the other hand, in the neck 65 of the funnel 62, there are arranged in-line type electron guns 67 which emit three electron beams 66B, 66G, 66R and are arranged in a line in the horizontal direction. The electron beams 66B, 66G and 66R are deflected by horizontal and vertical deflection magnetic fields generated by a deflection yoke 68 mounted outside the funnel 62, and horizontally and vertically scan the phosphor screen 63 via a shadow mask 64. Thus, a color image is displayed on the phosphor screen 63.
[0004]
In such a color cathode ray tube, in particular, the electron gun 67 is configured as an in-line type electron gun 67 that emits a center beam 66G passing on the same horizontal plane and a pair of side beams 66B and 66R on both sides thereof. The three electron beams 66B, 66G, and 66R are concentrated at the center of the phosphor screen 63 by decentering the positions of the side beam passage holes of the electrodes on the low-voltage side and the high-voltage side of the main lens portion of the main lens portion. By constructing the horizontal deflection magnetic field in the form of a pincushion and the vertical deflection magnetic field in the form of a barrel, a self-convergence type color cathode ray tube in which three electron beams 66B, 66G and 66R arranged in a line are self-concentrated over the entire screen is widely used. Has been put to practical use.
[0005]
An electron gun 67 used in such a color cathode ray tube has, for example, three cathodes K arranged in a row in a horizontal direction and a heater (not shown) for heating the cathodes K, as shown in FIG. ) And a plurality of grid electrodes consisting of a first grid electrode G1 to an eighth grid electrode G8 sequentially arranged in the direction of travel of the electron beams 66B, 66G, 66R from the cathode K to the phosphor screen 63, These grid electrodes G1 to G8 are supported and fixed in the neck 65 at predetermined intervals by an insulating support 69 made of bead glass, and a convergence cup CV is welded to the eighth grid electrode G8. On the side surface of the electron gun 67, an in-tube resistor 70 is provided along the longitudinal direction of the electron gun 67.
[0006]
Each of the grid electrodes G1 to G8 is biased to have a predetermined potential. For example, the third grid electrode G3 and the fifth grid electrode G5 are connected in common, and a voltage provided at an intermediate portion of the resistor 70 is provided. A predetermined focus voltage is supplied from the supply terminal R1, and the fourth grid electrode G4 and the sixth grid electrode G6 are connected in common. The fourth grid electrode G4 is connected to another voltage supply provided at an intermediate portion of the resistor 70. A voltage corresponding to about 35 to 45% of the anode voltage of about 25 to 35 kV is supplied from the terminal R2, and another voltage supply terminal R3 provided at an intermediate portion of the resistor 70 is connected to the seventh grid electrode G7. A voltage corresponding to about 50% to 70% of the anode voltage is supplied via the anode electrode, and the anode voltage is supplied to the eighth grid electrode G8 via another voltage supply terminal R4 and the convergence cup CV. Company has been applied, the respective grid electrodes G1 to G8, electron beam 66B, 66G, are formed as a plurality of electron lenses including a main lens for focusing the 66R on the phosphor screen 63. One end of the resistor 70 is grounded via the terminal R5.
[0007]
When the electron gun 67 thus constructed is operated, the neck 65 and the insulating support 70 are made of an insulating material made of glass, so that the voltage applied to each of the grid electrodes G1 to G8 is increased. The electric charge is accumulated on the surface of the inner wall of the neck 65, and the surface potential of the inner wall of the neck 65 is the highest in the vicinity of the eighth grid electrode G8, and gradually decreases toward the first grid electrode G1. Has become.
[0008]
The anode voltage applied to the eighth grid electrode G8 is a very high value of electric potential reaching 25 KV to 35 KV, and undesired protrusions such as burrs on low-potential electrodes such as the second grid electrode G2. If dust or the like is adhered, an electric field is concentrated on the protrusions or the dust, causing electron emission, causing a discharge in the tube and easily deteriorating the withstand voltage characteristics of the color cathode ray tube.
[0009]
If such an in-tube discharge phenomenon occurs, not only will the quality of the color cathode ray tube deteriorate significantly due to the instantaneous discharge current, but also the catastrophic damage such as destruction of circuit elements and the like due to the discharge current will be caused. It is also a factor.
[0010]
Therefore, as means for preventing such a discharge in the tube, an electrode between the low potential side as the electron beam forming portion and the high potential side forming the main lens portion, for example, a fifth grid electrode G5 is shown in FIG. As described above, the metallic ring 71 called a suppressor ring is wound and disposed so as to surround the insulating support 69 and the resistor 70. Then, the metallic ring 71 is heated in a high vacuum by high frequency heating from the outside of the neck 65 to evaporate a part of the metallic ring 71, thereby forming a metal deposition film 72 on the inner wall surface of the neck 65 and the surface of the resistor 70. ing.
[0011]
With this configuration, the accumulated charge in the corresponding portions is reduced by electrostatic induction between the metal deposition film 72 and the metallic ring 71 on the inner wall surface of the neck 65, and the neck 65 on which the metal deposition film 72 is formed is formed. The surface potential of the inner wall can be reduced, and discharge in the tube during operation can be prevented.
[0012]
Further, in order to improve the performance of the electron gun 67, a resistor 70 is provided on the side surface of the insulating support 69, and the anode voltage is divided by the resistor 70 by the resistor 70 to form an electron lens. It is formed so as to supply a voltage to the grid electrodes G3 to G7. The resistor 70 is provided with an anode voltage supply terminal R4, and is connected to each terminal R3, R2, R1 of the resistor 70 for supplying a voltage to the grid electrodes G7, G4, G3 and the like via the voltage supply terminal R4. The ground terminal R5 of the resistor 70 is grounded via the stem pin 73.
[0013]
[Problems to be solved by the invention]
However, in such an electron gun 67 assembly with a built-in resistor, since the metal ring 71 is formed so as to surround the insulating support 69 and the resistor 70, the surface of the metal ring 71 that is subjected to high-frequency heating is always in a state. It is in contact with the resistor 70. Therefore, in order to improve the withstand voltage characteristics of the cathode ray tube, a peak voltage (60 to 70 kV) which is about 2 to 3 times the normal operating voltage after the exhaust in the manufacturing process of the color cathode ray tube is completed. By applying a pulsed AC voltage to discharge forcibly, burrs and adhered substances of the grid electrodes G1 to G8 and the convergence cup CV constituting the electron gun 67 which cause a decrease in withstand voltage are removed. Withstand voltage treatment.
[0014]
When this high AC voltage is applied, an electric field is generated between the metallic ring 71 used for preventing the discharge in the tube or the low-pressure side of the resistor 70, which may cause a glow discharge. .
[0015]
That is, during the withstand voltage process, an AC high voltage is applied to the convergence cup CV, and the metal ring 71 is set to the ground potential, so that the resistor 70 is provided with the divided voltage supply terminals R3, R2, R1 and the like. An electric field may be generated between a high potential portion such as the convergence cup CV and the metallic ring 71 to generate a glow discharge. The glow discharge is an insulating film (not shown) covering the resistor 70. Is discharged through the upper layer.
[0016]
At this time, since the metal ring 71 is in contact with the metal deposition film 72 formed on the surface of the resistor 70, the terminal R4 connected to the convergence cup CV of the resistor 70 as shown in FIG. Functions as a positive electrode, and the metallic ring 71 functions as a negative electrode, and an electric field as shown by a symbol A in the figure is generated between the two electrodes. As a result, a glow discharge is generated along the surface of the resistor 70 by the positive corona streamer indicated by reference numeral B and the negative corona streamer indicated by reference numeral C in FIG.
[0017]
As a result, as shown in FIG. 11, between the interface a of the metal deposition film 72 on the resistor 70 formed by the metal ring 71 and the opposite surface b of the resistor 70 where the electric field on the + side reaches. , A potential difference occurs, and during this time, a dielectric breakdown of the resistor 70 occurs.
[0018]
When such a dielectric breakdown of the resistor 70 occurs, the voltage dividing operation by the normal resistance division cannot be performed, which causes a trouble such as a poor focus.
[0019]
In addition, the electron gun 67 having a gap between the main surface portion of the resistor 70 and the metallic ring 71 without keeping the main surface portion of the resistor 70 and the metallic ring 71 in close contact with each other is a feature of the present invention. It is disclosed in Japanese Unexamined Patent Publication No. 2001-155659. FIG. 10 of this publication describes an electron gun structure in which a gap is provided between a main surface of a voltage dividing resistor formed on beading glass and a metal wire.
[0020]
However, the metal wire disclosed in this publication is arranged with a gap from the main surface of the voltage dividing resistor, but is arranged in contact with the side surface of the beading glass and the side surface of the voltage dividing resistor. Because the contact point is at the ground potential, a glow discharge is generated through the voltage dividing resistor toward the ground potential point, which also causes dielectric breakdown of the voltage dividing resistor. These measures have not been taken nor taken into account.
[0021]
The present invention has been made in view of such problems, and even when a metallic ring is provided, it is possible to prevent the occurrence of a glow discharge caused by the metallic ring at the time of withstand voltage processing, and to provide a glow discharge. It is an object of the present invention to provide a cathode ray tube having improved withstand voltage characteristics capable of preventing occurrence of a focus defect due to the destruction of a resistor.
[0022]
[Means for Solving the Problems]
The present invention provides a substantially rectangular face panel, a funnel-shaped funnel connected to the face panel, a phosphor screen formed on an inner surface of the face panel, and an electron beam forming and fluorescent light arranged in a neck of the funnel. An electron gun configured to hold a plurality of grid electrodes to be focused on the body screen by an insulating support, and disposed on the insulating support for supplying a divided voltage to a selected grid electrode of the electron gun. A cathode ray tube having a resistor and a metal ring disposed so as to surround the resistor and the insulating support in a direction substantially orthogonal to the resistor, wherein the metal ring has at least an opposing surface of the resistor. Are arranged to be separated by a predetermined interval over all the regions between the two.
[0023]
As described above, even when a metallic ring is used, it is possible to obtain a cathode ray tube having improved withstand voltage characteristics by suppressing the occurrence of glow discharge due to the metallic ring during withstand voltage processing.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0025]
The cathode ray tube according to the present invention is configured as shown in FIG.
[0026]
That is, the face panel 11 has a substantially rectangular shape, and a funnel-shaped funnel 12 integrally joined to the face panel 11 has an envelope. The inner surface of the face panel 11 has blue, green, and red. A phosphor screen 13 composed of a stripe-shaped or dot-shaped three-color phosphor layer that emits light is formed, and a shadow mask 14 having a large number of apertures formed inside thereof is opposed to the phosphor screen 13 by a mask frame. The mask frame 15 is attached to the inside of the face panel 11 via an elastic support 16 and stud pins 17, and a magnetic shield plate 18 is attached to the mask frame 15.
[0027]
On the other hand, in the neck 19 of the funnel 12, there are arranged in-line type electron guns 21 which emit three electron beams 20B, 20G and 20R and are arranged in a line in the horizontal direction. The electron beams 20B, 20G, and 20R are deflected by horizontal and vertical deflection magnetic fields generated by a deflection yoke 22 mounted outside the funnel 12, and horizontally and vertically scan the phosphor screen 13 via a shadow mask 14. It is configured to display a color image on the phosphor screen 13.
[0028]
In such a color cathode ray tube, in particular, the electron gun 21 is configured as an in-line type electron gun 21 that emits a center beam 20G passing on the same horizontal plane and a pair of side beams 20B and 20R on both sides thereof. The three electron beams 20B, 20G, and 20R are concentrated at the center of the phosphor screen 13 by decentering the positions of the side beam passage holes of the low-voltage side electrode and the high-voltage side electrode of the main lens portion, thereby generating the deflection yoke 22. By forming the horizontal deflection magnetic field in a pincushion shape and the vertical deflection magnetic field in a barrel shape, a self-convergence type color cathode ray tube is formed.
[0029]
As shown in FIGS. 2 and 3, the electron gun 20 has three cathodes K arranged in a row in a horizontal direction, a heater H for heating the cathodes K, and electron beams 20B, 20G, It has a plurality of grid electrodes composed of a first grid electrode G1 to an eighth grid electrode G8 sequentially arranged in the traveling direction of 20R, and a convergence cup CV. Each of the grid electrodes G1 to G8 is an insulating material made of bead glass. It is supported and fixed at a predetermined interval by a support 23, and a resistor 24 is provided on a side surface of the insulating support 23 along the longitudinal direction of the insulating support 23. Is attached to the inner wall of the tube to which the anode voltage is supplied via the conductive spring 25 attached to the convergence cup CV welded to the eighth grid G8. Together with an anode voltage that crowded taken from Rafaito conductive film 26 is applied as it is, it is supplied to one end of the resistor 24 via the terminal strip 27.
[0030]
These grid electrodes G1 to G8 are biased to have a predetermined potential, the first grid electrode G1 is grounded or a negative potential, and the second grid electrode G2 is a low potential acceleration voltage of about 500 to 800V. Is applied, the third grid electrode G3 and the fifth grid electrode G5 are commonly connected, and a focus voltage of about 5 KV to 10 KV is applied through the terminal 27 of the resistor 24.
[0031]
Further, a voltage of about 35 to 45% of the anode voltage of about 25 to 35 KV is supplied to the sixth grid electrode G6 via a voltage supply terminal 27 provided at an intermediate portion of the resistor 24. A voltage of about 50 to 70% of the anode voltage is supplied to the electrode G7 via a voltage supply terminal 27 provided at an intermediate portion of the resistor 24, and the anode voltage is applied to the eighth grid G8 as it is. A terminal 27 for guiding to an earth pin 28 is provided at the other end of the device 24, and a plurality of electron lenses including a main lens for focusing the electron beam 19 on the phosphor screen 13 are formed by these grid electrodes G1 to G8. Have been.
[0032]
As described above, a plurality of voltage supply terminals 27 for dividing the anode voltage by resistance and supplying a bias are provided at an intermediate portion of the resistor 24. Further, as shown in FIG. On the outer periphery of G5, a suppressor ring is formed so as to surround the insulating support 23 and the resistor 24, for example, a tape-shaped metal band formed to have a thickness of about 0.1 mm and a width of about 1.0 mm. The metal rings 29 are separated from each other by a predetermined distance L and arranged in a non-contact state.
[0033]
The electron gun 21 configured as described above is disposed in the neck 19, and in a manufacturing process of the color cathode ray tube, the metallic ring 29 is heated at a high frequency so that the metal ring 29 is heated on the inner wall surface of the neck 19 and the outer surface of the resistor 24. A metal deposition film (not shown) is formed thereon.
[0034]
According to the cathode ray tube on which the metal vapor deposition film is formed, when the cathode ray tube is operated, the surface potential of the inner wall of the neck 19 is formed on the inner wall surface of the neck 19 by the voltage applied to each of the grid electrodes G1 to G8. By the electrostatic induction between the deposited metal film and the metallic ring 29, the surface potential of the inner wall of the neck 19 at the corresponding portion can be reduced, so that discharge in the tube during operation of the cathode ray tube can be prevented.
[0035]
As shown in FIG. 4, the metallic ring 29 is an intermediate electrode with a predetermined interval L so as not to contact either the insulating support 23 or the resistor 24 at the intermediate portion, for example, a fifth grid G5. Both ends are fixed by welding or the like on the side surface of the.
[0036]
When the metal ring 29 is attached and the withstand voltage processing of the cathode ray tube is performed as described above, the processing is performed by applying a pulsed AC high voltage of about 60 to 70 kV as described above, so that the convergence cup CV The positive side is the positive electrode and the metallic ring 29 side is the negative electrode. Even when an electric field is generated between the ± electrodes and a glow discharge occurs, the metallic ring 29 is fixed to the predetermined position from the resistor 24 and the insulating support 23. , The metal deposition film does not constitute a ground potential, that is, does not constitute a negative electrode.
[0037]
Therefore, even if a glow discharge current flows along the surface of the resistor 24, the glow discharge current does not flow into the metal deposition film that does not constitute the electrode, and the dielectric breakdown occurs between the metal deposition film interface and the surface of the resistor 24. Generation can be suppressed. Therefore, as a result of various studies on the distance L between the metallic ring 29 and the insulating support member 23 and the resistor 24, and particularly on the distance L between the metallic ring 29 and the resistor 24, the distance L was set to 0.005 mm to 2 mm. It has been found that setting the distance to 0.0 mm can most effectively prevent dielectric breakdown.
[0038]
That is, an experiment was conducted by changing the interval L variously, and as shown in FIG. 5, it was found that when the interval L was set to a value of 0.005 mm or more, the dielectric breakdown of the resistor 24 did not occur. However, if the distance L is set to 2 mm or more, the metallic ring 29 comes into contact with the inner wall of the neck 19, and a discharge is generated between the metal ring 29 and the inner wall of the neck 19, as shown in FIG. Thus, it has been found that the dielectric breakdown of the neck 19 occurs and the neck 19 itself is broken. From these points, it is possible to cope with both the dielectric breakdown of the resistor 24 and the dielectric breakdown of the neck 19 by setting the interval L within the range of 0.005 mm ≦ L ≦ 2.0 mm. It became.
[0039]
If the distance L can be ensured between the main surface of the resistor 24 on which the metal deposition film is formed, it is not necessary to set it strictly on the side surface of the resistor 24. It is also found that the insulation breakdown of the resistor 24 can be prevented only by keeping the side surfaces of the resistor 24 away from each other so that the arrangement of the resistor 24 and the metal ring 29 for maintaining the interval L is easy. It is possible to do. Of course, if this interval L is applied to the entire region of the resistor 24 and the insulating support 23 facing the metallic ring 29, the effect of suppressing the dielectric breakdown can be further improved.
[0040]
In order to secure the interval L, the inner diameter of the neck 19 is increased, the thickness of the metal ring 29, the resistor 24, or the insulating support 23 is reduced, or the insulating support of the electron gun 21 itself is used. This can be achieved by reducing the size in the 23 directions, for example, and can be achieved by any one of these methods or a combination thereof depending on the type of cathode ray tube used.
[0041]
Further, since the thickness of the metal deposited film is extremely small, that is, several μm or less, the thickness L of the metal deposited film can be ignored during actual design and manufacture. By setting, the purpose is achieved.
[0042]
Note that the present invention is not limited to these embodiments, and can be applied to, for example, a cathode ray tube in the form of an electron gun having a different electrode configuration. It goes without saying that various other applications and modifications are possible, such as being not limited to being placed on the electrodes, but being placed on other electrodes.
[0043]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent a dielectric breakdown of a resistor caused by a metallic ring due to a glow discharge generated during a withstand voltage process and to prevent a focus defect or the like from occurring. It is possible to obtain a cathode ray tube having excellent withstand voltage characteristics.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a cathode ray tube according to the present invention.
FIG. 2 is a perspective view showing a configuration of an electron gun part of the cathode ray tube.
FIG. 3 is a longitudinal sectional view showing a configuration of an electron gun part.
FIG. 4 is a cross-sectional view showing an arrangement relationship between a metal ring of an electron gun portion, an insulating support, and a resistor.
FIG. 5 is a characteristic diagram showing a dielectric breakdown occurrence rate of the resistor when the distance L between the metallic ring and the resistor is changed.
FIG. 6 is a characteristic diagram showing the rate of occurrence of dielectric breakdown at the neck when the distance L between the metallic ring and the resistor is changed.
FIG. 7 is a sectional view showing a conventional cathode ray tube.
FIG. 8 is a longitudinal sectional view showing a configuration of an electron gun part which similarly constitutes the cathode ray tube.
FIG. 9 is a cross-sectional view showing the positional relationship between the metal ring of the electron gun portion, the insulating support, and the resistor.
FIG. 10 is an explanatory diagram for explaining the state of occurrence of dielectric breakdown of the resistor.
FIG. 11 is an explanatory diagram for explaining a state in which a dielectric breakdown of the resistor is caused by the metallic ring.
[Explanation of symbols]
11 :: face plate 12: funnel 13: phosphor screen 19: neck 20B, 20G, 20R: electron beam 21: electron gun 23: insulating support 24: resistor 29: metallic ring G1 to G8: grid electrode CV: Convergence cup

Claims (3)

A substantially rectangular face panel,
A funnel-shaped funnel connected to this face panel,
A phosphor screen formed on the inner surface of the face panel,
An electron gun arranged in the neck of the funnel, configured to hold a plurality of grid electrodes for forming an electron beam and focusing on the phosphor screen by an insulating support;
A resistor disposed on the insulating support for supplying a divided voltage to a selected grid electrode of the electron gun;
In a cathode ray tube having a resistor and a metal ring disposed so as to surround the insulating support in a direction substantially orthogonal to the resistor,
A cathode ray tube, wherein the metallic ring is arranged at a predetermined interval over at least an entire area between the metallic ring and an opposing surface of the resistor. 2. The cathode ray tube according to claim 1, wherein a distance L between the metallic ring and the resistor is set to 0.005 mm ≦ L ≦ 2.0 mm at least on a main surface of the resistor. The distance L between the metallic ring and the resistor and the insulating support is set to 0.005 mm ≦ L ≦ 2.0 mm in all regions of the metallic ring facing the resistor and the insulating support. The cathode ray tube according to claim 1, wherein:

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