JP2002203493A - Cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode-ray tube having an improved withstand voltage characteristic with a simple structure without changing manufacturing facilities by resolving a problem of a conventional one that the distribution of a metal deposition film is narrow and an adequate withstand voltage characteristic can not be obtained although a metallic ring is disposed in an electron gun disposed in a cathode-ray tube neck, the metallic ring is heated from the outside to form a metal deposition film on the neck inside wall and thereby the potential of the neck inside wall is lowered. SOLUTION: Respective grid electrodes G1-G8 constituting the electron gun 20 disposed in the cathode-ray tube neck 18 are held by an insulating support body 23, the plural metallic rings SR-1 and SR-2 are so arranged as to surround the insulating support body 23 and a resistor 24 for feeding a divided voltage to a predetermined one of the grid electrodes, and the metallic rings SR-1 and SR-2 are heated, so that the metal deposition film 25 having a wide distribution is formed on the inside wall of the neck 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cathode ray tube,
More particularly, the present invention relates to a cathode ray tube in which a metal ring of an electron gun assembly is heated to form a metal deposition film on an inner wall of a neck.

[0002]

2. Description of the Related Art As shown in FIG. 6, a color cathode ray tube currently used in a general color television receiver and the like has a face panel 61 having a substantially rectangular shape, and is integrated with the face panel 61. Having an envelope made of a funnel-shaped funnel 62 joined to the
A phosphor screen 6 formed of a stripe or dot-shaped three-color phosphor layer that emits blue, green, and red light on an inner surface of the phosphor screen 6.
3 are formed and opposed to the phosphor screen 63,
A shadow mask 64 on which a number of apertures are formed is mounted inside.

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 three electron beams 66 are deflected by horizontal and vertical deflection magnetic fields generated by a deflection yoke 68 mounted outside the funnel 62,
Phosphor screen 63 via shadow mask 64,
The horizontal and vertical scanning allows the phosphor screen 6 to be scanned.
3 is configured to reproduce and display a color image.

In such a color cathode ray tube, in particular, a center beam 66 passing through an electron gun 67 on the same horizontal plane is used.
G and a pair of side beams 66B, 66R on both sides thereof
The electron gun 67 is configured as an in-line type electron gun 67. By eccentricizing 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 of the electron gun 67, three lines are provided at the center of the phosphor screen 63. Electron beam 66
B, 66G, and 66R are concentrated, and the horizontal deflection magnetic field generated by the deflection yoke 68 is configured as a pincushion type, and the vertical deflection magnetic field is configured as a barrel type. A self-convergence type color cathode ray tube has been widely put into practical use.

An electron gun 67 used in such a color cathode ray tube has, for example, as shown in FIG. 7, three cathodes K arranged in a row in a horizontal direction, and a heater (a heater for heating the cathodes K). (Not shown) and a plurality of electrodes consisting of a first grid electrode G1 to a fourth grid electrode G4 which are sequentially arranged from the cathode K side to the phosphor screen 63 in the traveling direction of the electron beam 66. The grid electrodes G1 to G4 are supported and fixed in the neck 65 at predetermined intervals by an insulating support 70 made of bead glass.

Each of these grid electrodes G1 to G4 has a first
The grid electrode G1 is grounded, a low-potential acceleration voltage of about 500 to 800 V is applied to the second grid electrode G2, a focus voltage of about 5 KV to 10 KV is applied to the third grid electrode G3, G4 has 25
An anode voltage of about KV to 35 KV is applied, and these grid electrodes G1 to G4
A plurality of electron lenses for focusing the electron beam 66 on the phosphor screen 63 are configured.

When the electron gun 67 constructed as described above is operated, the neck 65 and the insulating support 70 are applied to the grid electrodes G1 to G4, respectively, since they are made of an insulating material made of glass. Due to the applied voltage, charges are 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 higher as shown by a broken line a in FIG. Electrode G
The gradient has a gentle potential distribution gradient that decreases as it approaches 1.

The anode voltage applied to the fourth grid electrode G4 is an extremely high potential of 25 KV to 35 KV, and undesired burrs are applied to a low potential side electrode such as the second grid electrode G2. If such projections and dust are attached, the electric field is concentrated on the projections and dust and the like, causing an electron discharge to cause discharge in the tube, and the withstand voltage characteristic of the color cathode ray tube is easily deteriorated. .

If such an in-tube discharge phenomenon occurs, not only does the instantaneous discharge current significantly degrade the quality of the color cathode ray tube, but also the catastrophic failure of destroying circuit elements and the like by the discharge current. It also contributes to damage.

Therefore, conventionally, as means for preventing such a discharge in the tube, an electrode between the low potential side which is the electron beam forming part 69 and the high potential side which forms the main lens portion, for example, the third grid electrode G3 A metal ring SR called a suppressor ring is wound around the insulating support 70 and disposed. Then, the metallic ring SR is heated in a high vacuum by high frequency heating from outside the neck 65,
A part of the metal ring SR is evaporated to form a metal deposition film 71 on the inner wall surface of the neck 65 as shown in FIGS.

With this configuration, the accumulated charge in the corresponding portions of the metal deposition film 71 on the inner wall surface of the neck 65 and the metallic ring SR is reduced by the electrostatic induction as shown by a broken line b in FIG. And the surface potential of the inner wall of the neck 65 on which the metal deposition film 71 is formed can be lowered, and discharge in the tube during operation can be prevented.

The electron gun 67 is provided with a resistor (not shown) on the side surface of the insulating support 70, for example, in order to improve the performance. The resistor divides the anode voltage by the resistor. , Each grid electrode G3, G4 constituting the main lens
A type in which a voltage is supplied to a battery has been put to practical use. The resistor is provided with a voltage supply terminal (not shown), and is connected to supply a voltage to the grid electrode G3 and the like via the voltage supply terminal. In the electron gun 67 having such a built-in resistor, it is necessary to dispose a metallic ring SR in order to prevent discharge in the tube.

[0013]

However, in such an electron gun 67 having a built-in resistor, it is necessary to avoid a discharge between the metallic ring SR and a voltage supply terminal provided on the resistor. In addition, it is necessary to provide a predetermined distance between the metallic ring SR and the voltage supply terminal, and the location of the resistor is restricted depending on the specifications of the resistor. Moreover, the metallic ring SR disposed on the resistor side
The distance between the inner wall of the neck 65 and the inner wall of the neck 65 is only about 1 mm, and the metal deposited film 71 formed on the inner wall of the neck 65 is diffused as shown in FIG.
The length of the minor axis in the tube axis direction of 1 is at most 2 mm
However, there is a problem that it is not possible to have a wide range.

As one means of solving this problem,
It is conceivable to use a wide metal ring SR. However, since the metal ring SR is formed so as to surround the insulating support 70 and the resistor, the surface of the metal ring SR that is subjected to high-frequency heating is always The resistor is in contact with the resistor, so that the heat of the metallic ring SR is conducted to the resistor and is taken away. Therefore, when trying to obtain a wide range of the metal deposition film 71 using the wide metal ring SR, it is necessary to increase the output of the high frequency source for high frequency heating, and accordingly, the production equipment is increased and the power consumption is increased. And so on.

The present invention has been made in view of such problems, and can use existing equipment as it is, and can obtain a wide range of metal vapor-deposited films.
An object of the present invention is to obtain a cathode ray tube having improved withstand voltage characteristics.

[0016]

SUMMARY OF THE INVENTION The present invention provides a substantially rectangular face panel, a funnel-shaped funnel connected to the face panel, a phosphor screen formed on the inner surface of the face panel, and a neck of the funnel. An electron gun provided with a plurality of grid electrodes for forming an electron beam and focusing on the phosphor screen, and a plurality of metallic rings arranged in parallel with the electron gun; A cathode ray tube configured to have a metal deposition film corresponding to each metal ring formed on the inner wall of the neck by heating the metal ring.

As described above, the high-frequency heating high-frequency source is provided by using a plurality of metallic rings and arranging them adjacent to each other on electrodes of the same potential substantially at the middle between the two voltage supply terminals of the resistor. In addition to being able to efficiently heat without increasing the output of the metal, it is possible to form a metal deposition film that spreads over a wide range while preventing discharge between the metal ring and the voltage supply terminal of the resistor, Withstand voltage characteristics can be improved.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

The cathode ray tube of the present invention is configured as shown in FIG. That is, the face panel 11 has a substantially rectangular shape, and an envelope composed of a funnel-shaped funnel 12 integrally joined to the face panel 11. The inner surface of the face panel 11 has blue, green, and red. A phosphor screen 13 made of a stripe-shaped or dot-shaped three-color phosphor layer that emits light is formed on the phosphor screen 1.
3, a shadow mask 14 having a large number of apertures formed therein is attached to a mask frame 15, and the mask frame 15 is mounted on the inside of the face panel 11 via stud pins 16. A magnetic shield plate 17 is attached to the frame 15.

On the other hand, in the neck 18 of the funnel 12, there are arranged in-line type electron guns 20 which are arranged in a row in the horizontal direction and emit an electron beam 19 composed of three electron beams 19B, 19G and 19R. The three electron beams 19B, 19G, and 19R emitted from the electron gun 20 are deflected by horizontal and vertical deflection magnetic fields generated by a deflection yoke 21 mounted on the outside of the funnel 12, and the phosphor screen 13 is passed through a shadow mask 14. Is horizontally and vertically scanned to reproduce and display a color image on the phosphor screen 13. Further, the electron gun 20 is provided with a plurality of metal rings SR-1 and SR-2 described later. Have been.

In such a color cathode ray tube, in particular, the electron gun 20 has the center beam 1 passing on the same horizontal plane.
9G and a pair of side beams 19B and 19 on both sides thereof.
The electron gun 20 is configured as an in-line type electron gun 20 for emitting R. 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 electron gun 20, the three Of the electron beams 19B, 19G, and 19R of the
The self-convergence type color cathode ray tube is constituted by forming the horizontal deflection magnetic field generated by the pincushion type and the vertical deflection magnetic field by the barrel type.

As shown in FIG. 2, the electron gun 20 has three cathodes K arranged in a row in a horizontal direction, a heater (not shown) for heating the cathodes K, and an electron beam 19 from the cathodes K. A plurality of grid electrodes composed of the first grid electrode G1 to the eighth grid electrode G8 sequentially arranged in the traveling direction of the convergence cup CV
These grid electrodes G1 to G8 are supported and fixed at predetermined intervals by an insulating support 23 made of bead glass, and a side surface of the insulating support 23 is provided in a longitudinal direction of the insulating support 23. A resistor 24 is provided along the line, and an anode voltage is supplied to a high voltage side of the resistor 24.

Each of these grid electrodes G1 to G8 is 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 of about 500 to 800V. Is applied, the third grid electrode G3 and the 5-1st grid electrode G5-1 are connected in common, and a constant focus voltage of about 5 KV to 10 KV is applied from outside the cathode ray tube, and the 5-2nd grid electrode G5-1. The electrode G5-2 is provided with a dynamic focus voltage in which a parabolic AC voltage synchronized with the deflection frequency of the deflection yoke 21 is superimposed on a second focus voltage substantially equal to the focus voltage.

Further, the fourth grid electrode G4 and the sixth grid electrode G6 are commonly connected, and the fourth grid electrode G4
4 is supplied with a voltage of about 35 to 45% of an anode voltage of about 25 to 35 KV through a first voltage supply terminal R1-1 provided at an intermediate portion of the resistor 24. The grid electrode G7 has a second electrode provided at an intermediate portion of the resistor 24.
Of the anode voltage of 50 to 7
A voltage of about 0% is supplied, and the anode voltage is directly applied to the eighth grid G8.
To G8, the electron beam 19 is applied to the phosphor screen 1
A plurality of electron lenses including a main lens converging on 3 are formed.

As described above, in the middle portion of the resistor 24, the fourth
Voltage supply terminals R1-1 and R1-2 for dividing the anode voltage to the grid electrode G4 and the seventh grid electrode G7 by resistance and supplying a bias are provided, and the fourth grid electrode G4 and the seventh grid electrode are provided. Voltage supply terminal R1- to G7
1, the grid electrode located in the middle of R1-2,
The 5-1st grid electrode G5-1 is located.

On the outer periphery of the 5-1st grid electrode G5-1, two voltage supply terminals R1-1 and R1 of the resistor 24 are provided.
Two tape-like metal rings (suppressor rings) SR-1 and SR-2 are provided at an intermediate position substantially equidistant from the second supporter so as to surround the insulating support 23 and the resistor 24.
-1 grid electrode G5-1 is arranged adjacently on the same surface.

Specifically, the metallic rings SR-1,
SR-2 is made of a tape-shaped metal band formed to a thickness of about 0.1 mm and a width of about 1.0 mm, respectively.
About 10 m from the first voltage supply terminal R1-1 of the resistor 24
The first metallic ring SR-1 is placed at a distance of m
The second metallic ring SR-2 is arranged at a position spaced apart from the first metallic ring SR-1 by about 1 mm and about 11 mm from the first voltage supply terminal R1-1.

In other words, the first and second metallic rings SR-1 and SR-2 are connected to the first and second voltage supply terminals R
1-1 and R1-2 are arranged in close proximity at predetermined intervals, respectively, at a substantially central position, and the 5-1st grid electrode G5-
1, which are set on the same potential.

The electron gun 20 constructed as described above is disposed in the neck 18, and in the manufacturing process of the color cathode ray tube,
The metallic rings SR-1 and SR-2 are simultaneously subjected to high-frequency heating to form a metal vapor-deposited film 25 integrally on the inner wall surface of the neck 18 so as to partially overlap each other as shown in FIG.

Since the metal deposited films 25 are integrally formed so that the metal deposited films 25 deposited by heating the respective metallic rings SR-1 and SR-2 overlap each other, FIG. As shown in the figure, when compared with the width A of the short side in the tube axis direction of the metal deposition film 71 formed by the metal ring SR having the conventional configuration, the short side in the tube axis direction of the metal deposition film 25 formed by the present invention is compared. Is much larger such that B> A, and the metal deposition film 25 covers a wide area.
It can be.

At this time, the first and second metallic rings S
The metal-deposited films 25 formed by heating the metallic rings SR-1 and SR-2 by increasing the distance between R-1 and SR-2 are independent metal-deposited films separated from each other. It is also possible to form as 25,
Even in this case, although the effect of improving the surface potential of the inner wall of the neck is improved as compared with the case of the conventional single metal deposition film 71, these metallic rings SR-1 and SR- 2 and the resistor voltage supply terminals R1-1 and R1-
2 and the metallic rings SR-1 and SR-
2 and the voltage between the voltage supply terminals R1-1 and R1-2 of the resistor increase. In this regard, the two metal deposition films 25
Are overlapped on the same potential point so that the metallic rings SR-1,
By disposing SR-2 in close proximity, these inconveniences can be prevented, and a thicker and more effective metal deposited film 2 can be obtained.
5 can be attached to the inner wall of the neck 18, and the conventional high frequency source for heating the single metal ring SR can be used as it is, and any manufacturing equipment must be changed. There is no advantage.

According to the cathode ray tube on which the metal deposition film 25 is formed, when the cathode ray tube is operated, the surface potential of the inner wall of the neck 18 is reduced by the voltage applied to each of the grid electrodes G1 to G8. Extensive metal deposition film 25 formed on the surface and metallic rings SR-1 and SR-2
As shown by the solid line c in FIG. 5, the accumulated charges in the corresponding portions have a distribution in which the potential is greatly reduced, and the neck 18 on which the metal deposition film 25 is formed is formed.
Since the surface potential of the inner wall can be significantly reduced,
It is possible to prevent discharge in the tube during operation of the cathode ray tube.

As a result of a forced pressure test using the cathode ray tube having this configuration and a conventional cathode ray tube with a metallic ring, the number of intermittent discharges of the cathode ray tube of the present invention is smaller than that of the conventional product. It was confirmed that the withstand voltage characteristics were good.

The present invention is not limited to these embodiments, but may be applied to, for example, an electron gun having a different electrode configuration, an electron gun for black and white, and the like. It is also possible to arrange three or more without being limited to the above, the place to arrange is not limited to the 5-1 grid electrode, but may be arranged on other electrodes as long as a plurality of metallic rings can keep the same potential. It is needless to say that other various applications and modifications are possible, for example, it is not necessary to dispose it between the first and second voltage supply terminals.

[0035]

As described above, according to the present invention, the existing manufacturing equipment can be used as it is,
Moreover, a metallized film from a metallic ring can be formed over a wide area on the inner wall of the neck, and the potential on the inner wall surface of the neck can be greatly reduced. Obtainable.

[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 vertical cross-sectional view showing the configuration of an electron gun portion of the cathode ray tube.

FIG. 3 is an explanatory diagram showing a distribution state of a metal deposition film of the cathode ray tube according to the present invention.

FIG. 4 is an explanatory diagram showing a comparison between distribution states of metal deposition films of the present invention and a conventional cathode ray tube.

FIG. 5 is a characteristic diagram showing a potential distribution state of an inner wall of a neck of a cathode ray tube according to the present invention and a conventional one.

FIG. 6 is a sectional view showing a conventional cathode ray tube.

FIG. 7 is a longitudinal sectional view showing a configuration of an electron gun part which similarly constitutes the cathode ray tube.

FIG. 8 is an explanatory diagram showing a distribution state of a metal deposition film of a conventional cathode ray tube.

[Explanation of symbols]

 11: face plate 12: funnel 13: phosphor screen 18: neck 20: electron gun 23: insulating support 24: resistor 25: metal deposition film G1 to G8: grid electrode SR-1, SR-2: metallic ring

Claims (4)

[Claims] 1. 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 arranged in a neck of the funnel. Comprising: an electron gun having a plurality of grid electrodes formed and focused on the phosphor screen; and a plurality of metal rings arranged side by side with the electron gun, wherein the metal ring is heated. A cathode ray tube having a metal deposition film corresponding to each metallic ring formed on the inner wall of the neck. 2. The cathode ray tube according to claim 1, wherein the metal vapor-deposited film is formed by overlapping a part of each vapor-deposited film by a respective metallic ring. 3. The electron gun includes: an insulating support for holding the grid electrode; and a resistor formed on the insulating support and supplying a divided voltage to the predetermined grid electrode. 3. The cathode ray tube according to claim 1, wherein the plurality of metallic rings are arranged so as to surround the insulating support and the resistor. 4. The cathode ray tube according to claim 1, wherein the plurality of metallic rings are arranged close to each other on the same grid electrode.