JPH08138569A - Electron gun for cathode-ray tube - Google Patents

Abstract

PURPOSE: To prevent electric discharge between electrodes caused by electrostatic charging of an electrode support and improve the lens characteristics of the electron lens system. CONSTITUTION: An electron gun consists of the first to fifth frid G1 -G5 , among which the third to fifth G3 -G5 are pressure fitted and held in high resistance cylinders 17, 18. The first to third G1 -G3 are supported by a pair of glass supports 26, 27 having a resistance value of 1×10<9> thru 9×10<12> Ω.cm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun used for cathode ray tubes such as projector tubes, color picture tubes and index tubes.

[0002]

2. Description of the Related Art Hitherto, as a cathode ray tube electron gun, for example, a unipotential type electron gun shown in FIG. 6 has been widely used. This electron gun 1 has a plurality of electrodes, that is, a first grid G ₁ , a second grid G ₂ , a third grid G ₃ , and a fourth grid G _{4 with} respect to a cathode K that emits an electron beam.
And a fifth grid G ₅ are arranged coaxially (Z axis). An anode voltage (for example, 32 KV) is applied to the third grid G ₃ and the fifth grid G ₅ , and the fourth grid G ₄
It is applied focusing voltage (e.g. 9 KV), but these third grid G ₃ ~ fifth grid G ₅ by the main lens configured. Further, the first grid G ₁ , the second grid G _2, and the third grid G ₃ constitute a prefocus lens.

The first grid G ₁ to the fifth grid G ₅ are
An integral fixing piece 4 is fixed to this by embedding it in a pair of insulating beading glasses 2 and 3, and assembled integrally. First grid G ₁ to fifth grid G
₅ is made of metal such as stainless steel.

In this electron gun 1, the main lens is constructed.
3rd grid G₃~ Fifth grid G_FiveConcentricity between
Misalignment is likely to occur, which causes electron beam off-axis
And focus blur easily occurs. Also, the third grid G
₃~ Fifth grid G_FiveSince the distance between
As shown in 6, the on-axis potential gradient 5 becomes large,
3rd to 5th grid G ₃~ G_FiveDischarge occurs between
And the spherical aberration of the lens system becomes large,
The spot was getting bigger.

[0005]

On the other hand, the applicant of the present invention
In addition to reducing the electron beam off-axis,
The potential gradient between the electrodes is reduced to prevent discharge between the electrodes and
Providing an electron gun that can reduce the spherical aberration of the lens
I proposed. This electron gun has a cathode K as shown in FIG.
Against the first grid G₁~ Fifth grid G_FiveIs coaxial
The third grid that is arranged in the
G₃, 4th grid G_FourAnd the fifth grid G_FiveEach is yen
Press-fitted and fixed to the cylindrical first and second high-resistance cylinders 7 and 8.
Is integrated with the other first grid G ₁~ No.
3 grid G₃Is a normal insulating beading glass 2
And 3 supported.

The first and second high resistance cylinders 7 and 8 are made of, for example, a conductive ceramic, and in FIG. 4, the second high resistance cylinder 8 is larger than the first high resistance cylinder 7. It is formed with a large inner diameter. The third grid G ₃ and the fifth grid G ₅ are electrically connected to each other by a connection conductor (not shown).

In this electron gun 9, the _third to fifth grid electrodes G ₃ to G ₅ constituting the main lens are press-fitted into the first and second high resistance cylinders 7 and 8 having high roundness. Since they are integrally held together, the deviation of the concentricity of the main lens system hardly occurs. At the same time, the first high resistance cylinder 7 is provided between the third grid G ₃ and the fourth grid G ₄ , and the second high resistance cylinder 8 is provided between the fourth grid G ₄ and the fifth grid G ₅ , respectively. Therefore, as shown in FIG.
Since the potential gradient 10 on the axis becomes small and the beading glass can be omitted, the lens diameter becomes large and the spherical aberration of the lens system becomes small. In addition, the high resistance cylinders 7 and 8 allow the third grid electrode G ₃ to the fifth grid electrode
Since the discharge between the grid electrodes G ₅ is prevented, the electric field between the electrodes is stabilized.

By the way, in the electron gun 9 of FIG.
First grid electrode G₁~ Third grid electrode G₃But
Ordinary beading glass from rimmed glass composition 2
This beading glass 2 is supported by
And 3 are charged, so that the second grid G₂
And high pressure third grid G₃Discharge occurs between the grid G ₂
And G₃Disturbance of the electric field between them occurred.

In order to prevent the disturbance of the electric field, for example, as shown in FIG. 5, a recess 11 is provided in a portion of the beading glass ₂ and 3 corresponding to the second grid G ₂ and the third grid G _3. Things have been done, but it was not enough.

In view of the above points, the present invention provides an electron gun for a cathode ray tube capable of preventing the electrode support from being charged and preventing the interelectrode discharge and stabilizing the electric field between the electrodes.

[0011]

According to a first aspect of the present invention, in an electron gun for a cathode ray tube comprising a plurality of electrodes G _{1 to} G ₅ , the electrodes G _{1 to} G ₃ or G _{1 to} G ₅ are 1 × at room temperature. 10 ⁹ ~ 9
The structure is supported by the supports 26 and 27 having a resistance value of × 10 ¹² Ω · cm. If the resistance value of the supports 26, 27 is smaller than 1 × 10 ⁹ Ω · cm, thermal runaway of the leak current occurs, and if the resistance value is larger than 9 × 10 ¹² Ω · cm, it becomes close to an insulator and electrification occurs. .

The second invention is for a cathode ray tube according to the first invention.
In the electron gun, the supports 26 and 27 are made of MnO.₂, TiO
₂, Nb₂O_Five, V₂O_Five, Cu₂O, CrO₂, Fe
₃O _Four, MoO₂Has one or more additives selected from
The glass support is used.

A third aspect of the present invention is the electron gun for a cathode ray tube according to the first or second aspect of the invention, wherein the base bodies of the supports 26 and 27 are P.
The composition is bO glass or borosilicate glass.

A fourth aspect of the present invention is the first, second or third invention.
In the electron gun for the cathode ray tube of Ming,
First electrode G of the number of electrodes₁, The second electrode G₂And the third train
Pole G ₃To support.

[0015]

According to the first aspect of the present invention, in an electron gun for a cathode ray tube comprising a plurality of electrodes G _{1 to} G ₅ , the electrodes G _{1 to} G ₃ or G
By supporting _{1 to} G ₅ at room temperature with supports 26 and 27 having a resistance value of 1 × 10 ^{9 to} 9 × 10 ¹² Ω · cm,
The supports 26 and 27 are prevented from being charged, the discharge between the electrodes is prevented, and the electric field between the electrodes is stabilized. Since the electric field between the electrodes is not disturbed, the distance between the electrodes can be increased, so that the lens characteristics can be improved and the resolution can be increased. Further, the support 26, 27 does not need a recess for preventing the disturbance of the electric field, and the support 26, 27 can be easily manufactured. The resistance values of the supports 26 and 27 are 1 × 10 ^{9 to} 9 ×.
Since it is 10 ¹² Ω · cm, the leak current is slightly small enough to cause no problem, can be ignored, and thermal runaway of the leak current does not occur.

In the second aspect of the present invention, the supports 26 and 27 are M
nO₂, TiO₂, Nb₂O_Five, V ₂O_Five, Cu₂O,
CrO₂, Fe₃O_Four, MoO₂One or more selected from
By forming a glass support with the additive of
1 x 10 at room temperature⁹~ 9 × 10 ¹²Supporting resistance of Ω · cm
The body is obtained. Also, like ordinary beading glass
Electrodes can be supported by softening and embedding it in a fixed piece.

In the third aspect of the present invention, since the base material of the supports 26 and 27 is made of PbO-based glass or borosilicate-based glass, the so-called beading temperature at the time of supporting between the electrodes by the supports 26 and 27 is conventionally. Lower 400 ° C-50
It is possible to reduce the oxidation of the electrode since the temperature is 0 ° C.

In the fourth aspect of the present invention, the first of the plurality of electrodes is
By supporting the electrode G ₁ , the second electrode G _2, and the third electrode G ₃ with the high-resistance supports 26 and 27, the _{third to} fifth electrodes G _{3 to} G ₅ forming the other main lens are high in height. Resistance cylinder 17,
It is possible to support via 18 and there is no discharge between electrodes, and an electron gun with excellent lens characteristics can be obtained.

[0019]

Embodiments of the electron gun for a cathode ray tube according to the present invention will be described below with reference to the drawings.

1 and 2 (exploded view of FIG. 1) show the present invention.
An example of an electron gun for a cathode ray tube according to the above is shown. Cathode ray tube of this example
The electron gun 15 is applied to a unipotential type electron gun.
This is the case for the cathode K that emits an electron beam.
Each electrode, that is, the first grid G ₁, The second grid
G₂, 3rd grid G₃, 4th grid G_FourAnd 5th
Lid G_FiveAre arranged on the same axis and
The third grid G that constitutes the main lens₃, The fourth grid
De G_FourAnd the fifth grid G_FiveHigh resistance cylinders 14 and 15
Supported integrally via a lens to form a prefocus lens
First grid G₁, The second grid G₂And the third green
Dead G₃A pair of high resistance supports 26 and 27 which will be described later.
It is configured so as to be integrally supported by. Third Gu
Lid G₃And the fifth grid G_FiveIs the anode voltage (eg
32 KV) is applied and the fourth grid G _FourThere are four
A residue voltage (for example, 9V) is applied. Third grid G
₃And the fifth grid G_FiveAlthough not shown,
Electrically connected to each other.

First and second high resistance cylinders 17 and 18
Is, for example, Ti, W, Cu in alumina (Al ₂ O ₃ ).
It is composed of a substance having conductivity by mixing and firing oxides such as, a ferrite having conductivity, a titania ceramic, and the like. The high resistance cylinders 17 and 18 are formed in a cylindrical shape having a high roundness, and the ring-shaped electrode film 20 made of, for example, RuO ₂ -glass paste is formed on the inner surfaces of both end portions of the first high resistance cylinder 17. 21 is applied and formed, and the second
Similarly, on the inner surfaces of both ends of the high resistance cylinder 18 of
Ring-shaped electrode films 23 and 24 made of O ₂ -glass paste are formed by coating. On the inner surface between the electrode films 20 and 21 of the high resistance cylinder 17 and the inner surface between the electrode films 23 and 24 of the high resistance cylinder 18, a plurality of conductive rings 22 made of the same material as those of the electrode films are formed, respectively. 25 is formed. The second high resistance cylinder 18 is formed such that its inner diameter is larger than the inner diameter of the first high resistance cylinder 17.

On the other hand, the fourth grid G ₄ is formed such that the front half thereof has a large diameter portion having the same diameter as the fifth grid G _5, and the second half portion thereof has a small diameter portion having the same diameter as the third grid G _3. Is formed. The first high resistance cylinder 17 and the second high resistance cylinder 18 may be formed to have the same inner diameter, and in that case, the fourth grid G ₄ is formed to have the same diameter. Then, the front half of the fourth grid G ₄ and the fifth grid G ₅ are press-fitted and fixed to both ends of the second high resistance cylinder 18, respectively, and the rear half of the fourth grid G ₄ and the third grid G ₄ are fixed.
The first half parts of ₃ are press-fitted and fixed to both ends of the first high-resistance cylinder 17 respectively, and the third grid G ₃ to the fifth grid G
₅ are integrated. The first high-resistance cylinder 17 and the third grid G ₃ and the fourth grid G ₄ respectively have electrode films 20 and 2
The second high resistance cylinder 18 is electrically connected to the fourth grid G ₄ and the fifth grid G ₅ via the electrode films 23 and 24, respectively. Each of the plurality of conductive rings 22 and 25 suppresses variations in resistance between the upper and lower portions of the inner wall surface of the high resistance cylinders 17 and 18, and is used for equalizing potential in the vertical direction (Y-axis direction).

On the other hand, the rod-shaped supports 26 and 27 have a high resistance such that the leak current does not hinder, that is, 1 × 10 ^{9 to} 9 ×.
10 ¹² Ω · cm, preferably 1 × 10 ¹¹ to 1 × 10 ¹² Ω
-It is composed of a high resistance support having a resistance value of cm. When the resistance values of the supports 26 and 27 are smaller than 1 × 10 ⁹ Ω · cm, thermal runaway of the leak current between the second grid G ₂ and the third grid G ₃ is likely to occur, and the resistance value is 9 × 10.
^If it exceeds ¹² Ω · cm, the supports 26 and 27 are charged toward the insulator, which is not preferable.

Examples of the high resistance supports 26 and 27 include MnO ₂ , TiO ₂ , Nb ₂ O ₅ and V.
It can be formed of a glass support to which one or more conductivity imparting substances such as ₂ O ₅ , Cu ₂ O, CrO ₂ , Fe ₃ O ₄ , and MoO ₂ are added. As a base material of this glass support, PbO-based glass or borosilicate-based glass can be used.

The first grid G ₁ to the third grid G ₃ are assembled by the first grid G having the fixing pieces 28 integrally formed therein.
₁ , the second grid G ₂ and the third grid G ₃ are arranged at predetermined positions via a beading jig, and the fixing pieces 28 are made to bite the heat-softened supports 26 and 27, and gradually cooled to be integrated. Turn into.

According to the electron gun 15 according to the above-mentioned embodiment,
Third grid G that constitutes the main lens ₃, 4th grid G
_FourAnd the fifth grid G_FiveIs the first and second with high roundness
Pressed into the high resistance cylinders 17 and 18 and supported integrally.
Therefore, like the electron gun of FIG. 4 described above,
Almost no deviation of concentricity occurs. And the first and the first
The second high resistance cylinders 17 and 18 allow the third grid G₃
And the fourth grid G_FourIn the 4th grid G_FourAnd 5th
Lid G_FiveThe potential gradient on the axis between
Since the traditional beading glass can be omitted,
And the fifth grid G_FourAnd G_FiveLens system as shown in
In addition to being able to make it large, the spherical aberration of the main lens can be made small.
Can be done. Further, the first and second high resistance cylinders
The third grid G by the bodies 17 and 18₃~ 5th click
De G_FiveSince the distance between the electrodes of the
Dead G₃, 5th grid G_FiveAnd the fourth grid G_FourBetween
Can be prevented from being discharged.

Therefore, in the present embodiment, the first grid G
₁~ Third Grid G₃1 x 10 ⁹~ 9 × 10¹²Ω ・
cm, preferably 1 × 10¹¹~ 1 × 10¹²Ω · cm
Supporting with supports 26 and 27 having resistance
Prevents the support bodies 26 and 27 from being charged.
Can be reduced or reduced. Therefore,
Between lids, especially the second grid G₂(Eg 700V)
Third grid G₃(For example, 32KV)
Can be prevented, the second and third grid G ₂And G
₃The electric field between them can be stabilized.

The resistance value of the supports 17 and 18 at room temperature is 1
× 10 ^{9 to} 9 × 10 ¹² Ω · cm, preferably 1 × 10 ¹¹
Since it is ˜1 × 10 ¹² Ω · cm, the leak current between the second grid G ₂ and the third grid G ₃ can be ignored, and thermal runaway of the leak current does not occur. It does not adversely affect the voltage supply. It should be noted that instead of the supports 26 and 27, the first, second and third grids G ₁ , G ₂ and G ₃ are supported by being press-fitted into a high resistance cylinder similar to the high resistance cylinders 17 and 18. However, in this case, the total resistance value decreases, and thermal runaway easily occurs. However, in the case of being supported by the pair of supports 26 and 27 as in this example, the total resistance value is high, and thermal runaway is unlikely to occur. The supports 26 and 27 formed by adding the above-mentioned conductivity-imparting substance to PbO-based glass or borosilicate-based glass have a beading temperature of 400.
C. to 500.degree. C. (conventionally high temperature of 1300.degree. C.), the beading jig is less damaged, and the grid is less oxidized.

Since the electric field between the _second and third grids G ₂ and G ₃ is not disturbed, the distance between the grids can be increased, so that the lens characteristics of the prefocus lens can be improved and the resolution can be further improved. can do. Since it is not necessary to provide the recesses 11 as shown in FIG. 5 in the supports 26 and 27, the shape of the supports can be simplified and the manufacturing cost can be reduced accordingly.

FIG. 3 shows another embodiment of the present invention. In the electron gun 31 of this example, the first grid G ₁ , the second grid G ₂ , the third grid G ₃ , and the fourth grid G ₄ are applied to the cathode K that emits an electron beam, as in FIG. 6 described above. And the fifth grid G ₅ is arranged coaxially (Z axis). An anode voltage (for example, 32 KV) is applied to the third grid electrode G ₃ and the fifth grid G ₅ , a focus voltage (for example, 9 KV) is applied to the fourth grid G ₄ , and the third grid G ₃ to the fifth grid G 5 are applied. The main lens is composed of G ₅ . The first grid G ₁ , the second grid G ₂ and the third grid
The grid G ₃ constitutes a prefocus lens. In the present example, the first grid G ₁ ~
The 5th grid G ₅ has the above-mentioned 1 × 10 ^{9 to} 9 × 10 ¹² Ω.
-Cm, preferably a pair of supports 26 and 27 having a resistance value of 1 × 10 ¹¹ to 1 × 10 ¹² Ω · cm. In the electron gun 31 having such a configuration, similarly to the above example, the high resistance supports 26 and 27 are used to form the grids G _{1 to} G.
_{Since the 5} is supported, it is possible to prevent or reduce the charge on the supports 26 and 27, and it is possible to prevent discharge between the grids. Moreover, since the distance between the electrodes can be increased, the lens characteristics can be improved and the resolution can be improved. Furthermore, since it is not necessary to provide the recesses 11 shown in FIG. 5 in the supports 26 and 27, the manufacturing cost of the supports 26 and 27 can be reduced.

Although the above example is applied to the unipotential type electron gun, it is also applicable to other bipotential type electron guns.

[0032]

The electron gun for a cathode ray tube according to the first aspect of the present invention
According to, 1 x 10 at room temperature⁹~ 9 × 10 ¹²Ω · cm resistance
Since each electrode is supported by a support having a value,
Can be prevented or reduced.
it can. As a result, the discharge between the electrodes of the electron gun
It can be reduced and the electric field between the electrodes can be stabilized. Well
In addition, since the distance between the electrodes can be increased,
It is possible to improve the image characteristics and improve the resolution.
Can be. In addition, conventional supports (beading glass)
Since the recesses formed in the
The cost can be reduced.

According to the second aspect of the present invention, since the support is formed of a glass support having a conductive additive, 1 × 1
A support having a high resistance value of ^{09 to} 9 × 10 ¹² Ω · cm can be formed, and the support between the electrodes can be obtained by the same method as that of a usual insulating beading glass, that is, by softening by heating. It can be carried out.

According to the third aspect of the present invention, since the PbO-based glass or the borosilicate-based glass is used as the base material of the support, the beading temperature can be made lower than the conventional temperature. Damage can be reduced and electrode oxidation can be reduced.

According to the fourth aspect of the present invention, the reliability of the electron gun formed by integrating the third to fifth electrodes forming the main lens via the high resistance cylinder can be further improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of an electron gun for a cathode ray tube according to the present invention.

FIG. 2 is an exploded view of the electron gun for the cathode ray tube of FIG.

FIG. 3 is a configuration diagram showing another example of an electron gun for a cathode ray tube according to the present invention.

FIG. 4 is a configuration diagram of a cathode ray tube electron gun according to a comparative example and a potential distribution diagram of essential parts.

FIG. 5 is a configuration diagram of a main part of an electron gun for a cathode ray tube of a comparative example.

FIG. 6 is a configuration diagram of a cathode ray tube electron gun according to a conventional example and a potential distribution diagram of essential parts.

[Explanation of symbols]

1,9,15,31 electron gun G ₁ ~G ₅ grid K cathode 2 insulating beading glass 4, 28 fixed piece 7,8,17,18 high resistance cylinder 20, 21, 22, 23, 24,25 Electrode film 26,27 High resistance support

Claims (4)

[Claims] 1. An electron gun for a cathode ray tube comprising a plurality of electrodes, wherein the electrodes have a temperature of 1 × 10 ^{9 to} 9 × 10 ¹² Ω.
An electron gun for a cathode ray tube, which is supported by a support having a resistance value of cm. 2. The support is MnO ₂ , TiO ₂ , N
b ₂ O ₅ , V ₂ O ₅ , Cu ₂ O, CrO ₂ , Fe
_The electron gun for a cathode ray tube according to claim 1, wherein the electron gun is formed of a glass support having one or more kinds of additives selected from ₃ O ₄ and MoO ₂ . 3. The substrate of the support is a PbO-based glass or a borosilicate-based glass, wherein the base material is PbO-based glass or borosilicate-based glass.
An electron gun for a cathode ray tube according to. 4. The electron gun for a cathode ray tube according to claim 1, wherein the support member supports the first electrode, the second electrode and the third electrode among the plurality of electrodes.