JP2001256896A - Cathode support structure for cathode ray tube and cathode ray tube using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode support structure for a cathode ray tube with a plurality of cathode structures arranged in line for uniformizing the electron emitting characteristics of the plurality of cathode structures at the beginning of power supply by correcting the thermal deformation of a first grid without decreasing the reliability or increasing the number of parts and the number of producing processes. SOLUTION: Insulating supports 14 are fixed and arranged into a supporting frame 11 and a plurality of cathode holding cylinders 12 and a plurality of heater fixing terminals 13 are mutually arranged in line via the insulating supports 14. The cathode structures 15 are respectively mounted in the plurality of cathode holding cylinders 12. A cathode holder 22a located at the center out of cathode holders 22 constituting the plurality of cathode structures 15 is formed of a metal material having a greater thermal expansion coefficient than that of cathode holders 22b located at both outsides thereof. The first grid 10 is arranged above the cathode support structure B to form an electron gun structure A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode support structure used for a cathode ray tube, and more particularly to a highly reliable cathode support structure for a cathode ray tube having improved electron emission characteristics after power is turned on, and a cathode ray tube using the same. .

[0002]

2. Description of the Related Art As one form of an electron gun structure used for a cathode ray tube, there is known an electron gun structure having, for example, an in-line type cathode support structure having a structure as shown in FIG. FIG. 3 shows the vicinity of the cathode support structure in the electron gun structure, where A is the electron gun structure, and B is the cathode support structure.

In the cathode support structure B shown in FIG. 1, reference numeral 1 denotes a metal support frame formed of, for example, an Fe--Ni alloy, which has a substantially elliptical flat surface having upper and lower surfaces opened. It is. This support frame 1
, A plurality of cathode holding cylinders 2 and a heater connector support member 3 are arranged side by side at predetermined intervals. The cathode holding cylinder 2 and the heater connector support member 3 are integrally fixed to the support frame 1 by an insulating support 4.

A plurality of cathode holding cylinders 2 each have a cathode structure 5 mounted therein. As the cathode structure 5, one using an oxide type cathode substrate or an impregnated type cathode substrate is known, but with the recent increase in size and definition of cathode ray tubes, the impregnated type cathode substrate is often used. It is becoming.

As a cathode structure 5 having an impregnated cathode base 6, a cathode sleeve 8 is coaxially arranged in a cylindrical cathode holder 7 mounted on the cathode holding cylinder 2, and a heater is provided in the cathode sleeve 7. In addition, an arrangement in which an impregnated cathode base 6 is disposed at the upper end of a cathode sleeve 7 is known. The impregnated-type cathode substrate 6 contains BaO, CaO, and Al ₂ O in pores of a porous substrate made of a refractory metal such as W.
An electron emitting material such as ₃ is melt-impregnated, and its surface is coated with a metal film such as an Ir or Os-Ru alloy.

A first grid 9 having a plurality of electron beam passage holes 9a is arranged above the above-described cathode support structure B, and an electron gun structure A is constituted by these components. The first grid 9 is formed of a metal material, and has a cup shape with an open lower surface. Such a first grid 9 is arranged such that each electron beam passage hole 9 a is located above the impregnated cathode base 6.

[0007] The electron gun assembly A thus configured is combined with another grid to form an electron gun, and this electron gun is mounted inside the neck of the cathode ray tube. Thereafter, the cathode ray tube is manufactured through a required evacuation step and aging step. The above-described electron gun assembly A is suitable for forming a relatively small in-line type electron gun, and has a smaller number of components compared to a conventional type in which three electron gun assemblies are separated. Has advantages.

[0008]

However, the electron gun assembly A having the in-line type cathode support structure B as described above has advantages such as a small number of components, but has the following problems. have.

That is, the impregnated cathode base 6 is heated by a heater when power is supplied to the cathode ray tube, and an electron beam is emitted based on the heating of the impregnated cathode base 6. At this time, a cathode current flows through the beam passage hole 9a of the first grid 9. This cathode current greatly varies depending on the distance between the first grid 9 and the cathode base 6. Immediately after the power is turned on, the cathode base 6 moves toward the first grid 9 and thereafter moves in the opposite direction due to the thermal expansion of the peripheral members. When the thermal expansion is stabilized, the cathode current is stabilized.

However, in the case of the conventional electron gun assembly A, there is a problem that the cathode current of the cathode assembly 5 in the central portion becomes smaller than that of the cathode assemblies 5 on both outer sides at the initial stage of power-on, and the color tone balance is lost. . This is because the first grid 9 is thermally deformed and curved to the opposite side to the cathode base 6 at the initial stage of turning on the power, and the first grid 9 is located between the cathode base 6 in the center and the first grid 9 as compared with the cathode bases 6 on both outer sides. This is because the interval increases.

For the above-mentioned problems, for example, the following countermeasures have been studied. That is, among the plurality of cathode holding cylinders 2 fixed to the insulating support 4, a configuration in which the thermal expansion coefficient of the cathode holding cylinder at the center is larger than the cathode holding cylinders on both outer sides is being studied. However, in this case, the difference in thermal expansion coefficient between the insulating support 4 and the cathode holding cylinder 2 at the center becomes large, and the bonding strength between the insulating support 4 and the cathode holding cylinder 2 at the center is insufficient. Problems occur. In addition, chips and cracks are generated at the bonding edge portion, and it cannot be practically used. Generally, the difference in thermal expansion coefficient between the insulating support 4 and the cathode holding cylinder 2 is limited to about 1.3 times, and if it is larger than this, it is not possible to obtain a sufficient adhesive strength.

Further, a countermeasure as shown in FIG. 4 has been studied. That is, in the cathode support structure shown in FIG. 4, in order to maintain the adhesive strength with the insulating support 4, a double-structured cathode holding cylinder 2 'is adopted as the cathode holding cylinder at the center. That is, a metal having a thermal expansion coefficient substantially equal to that of the insulating support 4, for example, Fe-Ni-Co
A cylinder 2a made of an alloy is arranged.
In order to correct the thermal deformation of the grid 9, a cylinder 2b made of a metal material having a larger thermal expansion coefficient than the outer cylinder 2a is arranged. These cylinders 2a and 2b are welded at a plurality of points substantially at the center of the thickness of the insulating support 4.

According to such a configuration, the first thermal expansion difference between the insulating support 4 and the cathode holding cylinder 2 'is corrected while the first thermal expansion difference is maintained.
Disruption of the color tone balance due to thermal deformation of the grid 9 can be suppressed. However, there is a problem that as the number of components increases, the number of welding steps increases, and the manufacturing cost of the cathode support structure B increases based on these.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and has made it possible to make the electron emission characteristics of a plurality of cathode assemblies uniform at the initial stage of turning on the power without increasing the number of parts or the number of manufacturing steps. It is an object of the present invention to provide a cathode support structure for a cathode ray tube, which is capable of stably maintaining a color tone balance from an early stage of power supply, and a cathode ray tube using the same.

[0015]

According to a first aspect of the present invention, there is provided a cathode support structure for a cathode ray tube, comprising: a support frame; an insulating support fixedly arranged in the support frame; A plurality of cathode holding cylinders arranged in-line in the support frame via the insulating support, and a cathode holder mounted in each of the plurality of cathode holding cylinders. A plurality of cathode assemblies in each of which a cathode base is provided at an upper end of a cathode sleeve disposed in the cathode holder; The cathode holders located at the first and second portions are made of a metal material having a larger coefficient of thermal expansion than the cathode holders located at both outer sides thereof.

According to a sixth aspect of the present invention, there is provided a cathode ray tube comprising: an envelope formed by a panel portion, a funnel portion and a neck portion; and a fluorescent film formed on an inner surface of the panel portion. A cathode ray tube comprising: an electron gun assembly disposed in the neck portion;
The cathode support structure for a cathode ray tube of the present invention described above, and disposed above the support frame in the cathode support structure,
And a first grid having an electron beam passage hole.

As described above, in the present invention, among the cathode holders constituting a plurality of cathode assemblies, the cathode holder located at the center is made of a metal material having a larger coefficient of thermal expansion than the cathode holders located on both outer sides thereof. ing. For this reason, even when the first grid is thermally deformed and curved to the opposite side to the cathode base in the initial stage of turning on the power, the cathode holder located at the center moves to the first grid side based on its large thermal expansion coefficient, The distance between the first grid and the first grid can be equal to the distance between the cathode holders on both outer sides and the first grid. That is, the thermal deformation of the first grid can be corrected based on the thermal expansion coefficient of the cathode holder located at the center.

Further, since the thermal deformation of the first grid is corrected by using a material having a large thermal expansion coefficient for the cathode holder as described above, the insulating support and the cathode holding member are provided as in the conventional cathode supporting structure. There is no possibility that a problem such as insufficient bonding strength with the cylinder occurs. Also,
The number of parts and the number of manufacturing steps are the same as those of the conventional cathode support structure, and the manufacturing cost does not increase.

As described above, according to the cathode support structure for a cathode ray tube of the present invention, for example, the thermal deformation of the first grid at the initial stage of turning on the power can be performed without lowering the reliability of the cathode support structure or increasing the manufacturing cost. Can be corrected by the cathode holder located at the center. These make it possible to keep the color tone balance of the cathode ray tube constant at an inexpensive and highly reliable state from the initial stage of power-on.

In the cathode support structure for a cathode ray tube according to the present invention, the coefficient of thermal expansion of the cathode holder located at the center is 1.6 to 1.6 of the coefficient of thermal expansion of the cathode holders located on both outer sides thereof. Preferably it is 2.4 times.
This makes it possible to correct the thermal deformation of the first grid satisfactorily and with good reproducibility. The cathode support structure for a cathode ray tube of the present invention is applicable to both cases of using an impregnated cathode substrate and an oxide cathode substrate.

[0021]

Embodiments of the present invention will be described below.

FIG. 1 is a partial sectional view showing an embodiment of a cathode support structure for a cathode ray tube according to the present invention and an example of an electron gun assembly using the same. In the figure, reference numeral A denotes an electron gun assembly configured by disposing a first grid 10 on a cathode support assembly B. Hereinafter, the cathode support structure B will be described in detail.

The cathode support structure B has a metal support frame made of, for example, an Fe—Ni alloy.
The support frame 11 has an upper surface and a lower surface that are open, and has a substantially elliptical planar shape. Inside the support frame 11, a plurality of cathode holding cylinders 12 provided with a flare at the upper end are arranged inline. The cathode holding cylinder 12 is, for example, Fe-N
It is formed of an i-Co alloy.

FIG. 1 shows the structure of a cathode support structure B in which three cathode holding cylinders 12 are arranged inline.
These three cathode holding cylinders 12 are arranged side by side with the heater connector support member 13 at a predetermined interval. Such a cathode holding cylinder 12 and the heater connector support member 13 are integrally fixed to the support frame 11 by an insulating support 14 fixedly arranged in the support frame 11. The insulating support 14 is made of, for example, ZnO-B ₂
It is made of an O ₃ —SiO ₂ crystallized glass and has a coefficient of thermal expansion of about 50 × 10 ⁷ / ° C.

[0025] The cathode holding cylinder 12 of a plurality of the above-described (3), the cathode structure 15 ₂ are respectively ₂ inserted arranged from its lower opening. The cathode structure 15 may use either an impregnated cathode substrate or an oxide cathode substrate. Here, the _two- cathode assembly 15 having an impregnated cathode substrate will be described in detail.

FIG. 2 is a view showing the structure of the impregnated _two- cathode assembly 15. In FIG. 2, reference numeral 16 denotes a cathode sleeve made of a cylindrical body whose upper end and lower end are open, and a heater 17 is arranged inside the cathode sleeve 16. The cathode sleeve 16 is formed of, for example, Ta.

The inner peripheral surface of the cathode sleeve 16 is coated with a blackening layer made of alumina and heat-resistant metal powder in order to lower the operating temperature of the heater 17.
Outside the cathode sleeve 16, a reflection tube 18 made of, for example, a Ni-W alloy is coaxially arranged. As the heater 17, a coiled double helical type heater is used, and an electrode connection tab 19 made of a stainless steel alloy is fixed to the lower end of the heater 17 by laser welding.

A cup-shaped member 20 made of, for example, Ta is fixed to the upper end opening of the cathode sleeve 16. In the cup-shaped member 20, an impregnated cathode base 21 in which a porous base made of a high melting point metal is melt-impregnated with an electron emitting substance is provided. The impregnated cathode base 21 is made of W, Mo, R
e, or a porous substrate made of a refractory metal such as an alloy thereof and having a porosity of, for example, 15 to 20%. An electron emitting material is melt-impregnated in the pores of the porous substrate.

As the electron emitting material, for example, BaO and C
A composite oxide in which aO and Al ₂ O ₃ are mixed at a molar ratio of 4: 1: 1 is used. However, the electron emitting material used in the present invention is not necessarily limited to the above-described composite oxide, and various oxides can be used as long as desired electron emitting characteristics can be obtained. A metal film made of Ir, Os, Ru, or an alloy thereof is formed on the surface of a porous substrate (metal having a high melting point) in which the electron emitting material is melt-impregnated in the pores. This constitutes the impregnated cathode base 21.

A cathode holder 22 is disposed coaxially with the cathode sleeve 16 so as to surround the cathode sleeve 16 and the reflecting tube 18 so as to surround the cathode sleeve 16. A plurality (for example, three) of strip-shaped straps 23 are arranged between the cathode holder 22 and the cathode sleeve 16, and each of the strip-shaped straps 23 has an upper end on the cathode holder 22 and a lower end on the cathode sleeve. 16 is fixed to the outer surface by laser welding or the like. The cathode sleeve 16 is supported by the cathode holder 22 by these strip-shaped straps 23.

Here, the cathode structures 15 are mounted in the three cathode holding cylinders 12, respectively.
Of the cathode holders 22 constituting the three cathode assemblies 15,
The cathode holder 22a located at the center is made of a metal material having a larger coefficient of thermal expansion than the cathode holders 22b located on both outer sides thereof. The components of the cathode structure 15 excluding the cathode holder 22, for example, the cathode sleeve 16, the reflection tube 1
8. The same material is used for the three cathode assemblies 15 for the cup-shaped member 20 and the like.

As described above, the constituent material (coefficient of thermal expansion: α ₁ ) of the cathode holder 22a located at the center and the constituent material (coefficient of thermal expansion: α ₂ ) of the cathode holder 22b located on both outer sides thereof are different. Metal material with a large coefficient of thermal expansion (α ₁ > α
By using ₂ ), the thermal deformation of the first grid 10 can be corrected based on the large thermal expansion coefficient of the cathode holder 22a located at the center. In other words, even when the first grid 10 is thermally deformed and curved to the opposite side to the cathode structure 15 in the initial stage of turning on the power, the cathode holder 22a located at the center is located on the first grid 10 side based on its large thermal expansion coefficient. In order to move, the distance between the first grid 10 and the first grid 10 is adjusted by the outermost cathode holders 22a and the first grid 10.
Is equal to the distance between Thereby, the first grid 1
It is possible to correct the thermal deformation of zero.

In order to obtain the effect of correcting such thermal deformation of the first grid 10, the cathode holder 2 located at the central portion
2a is preferably made of a metal material having a thermal expansion coefficient 1.6 to 2.4 times the thermal expansion coefficient of the cathode holders 22b located on both outer sides thereof. Cathode holder 22b in which the thermal expansion coefficient of cathode holder 22a located in the center is located outside
If it is less than 1.6 times that of the first grid 10, the correction of the amount of thermal deformation of the first grid 10 may be insufficient. On the other hand, when the coefficient of thermal expansion of the cathode holder 22a exceeds 2.4 times that of the cathode holder 22b, the amount of thermal deformation is excessively corrected, and conversely, the cathode base 21 located at the central portion becomes too close to the first grid 10 side and the cathode The current increases and the color balance is lost.

The constituent materials of the cathode holder 22a located at the center and the cathode holder 22b located at the outside satisfy the above-described coefficient of thermal expansion (α ₁ > α ₂ ), and In order to match the thermal expansion coefficient with other members such as the cylinder 12, the cathode holder 22 a
An e-Ni alloy is used, and F
It is preferable to use an e-Ni-Co alloy. For example, as a constituent material of the cathode holder 22a, Fe-50 mass%
When a Ni alloy is used, its thermal expansion coefficient is
It is about twice as large as that of the Fe-Ni-Co alloy as the constituent material of 2b. By using such alloys, it is possible to satisfactorily correct the thermal deformation of the first grid 10.

The first grid 10 is arranged above the above-mentioned cathode support structure B so that the electron beam passage hole 10a is located on the cathode base 21, and these constitute the electron gun assembly A. . The first grid 10 has a cup shape with an open lower surface, and the distance between the electron beam passage hole 10a and the cathode base 21 is accurately set by, for example, an air micro method. It is fixed by welding or the like.

The electron gun structure A thus constructed
Is combined with another grid arranged at a predetermined interval above the first grid 10 and mounted on the neck of the cathode ray tube as an electron gun. Thereafter, the cathode ray tube is manufactured through a required evacuation step and aging step.

The cathode ray tube of the present invention includes the above-described cathode support structure B and further includes the electron gun structure A. As a specific configuration, it includes an envelope configured by a panel portion, a funnel portion, and a neck portion, a fluorescent film formed on an inner surface of the panel portion, and an electron gun structure arranged in the neck portion. The electron gun assembly uses the cathode support structure of the present invention.

In the above-described cathode support structure B of the present invention and the electron gun structure A having the same, the cathode support structure B is located at the center of the cathode holders 22 constituting the plurality of cathode structures 15 arranged in-line. Since the cathode holder 22a is made of a metal material having a higher coefficient of thermal expansion than the cathode holders 22b located on both outer sides thereof, the first holder is firstly turned on at the beginning of power-on.
Even if the grid 10 is curved by thermal deformation to the opposite side to the cathode structure 15, the cathode 10 moves to the first grid 10 side due to a large thermal expansion coefficient of the cathode holder 22a located at the center, and thereby the first grid 10 To the outer cathode holder 22b.
Can be corrected equivalently. Therefore, the cathode current can be stabilized, that is, the electron emission characteristics of the plurality of cathode structures 15 can be made uniform, and the color tone balance can be kept stable from the initial stage of turning on the power.

Further, since the thermal deformation of the first grid 10 is corrected by the cathode holder 22, the cathode holding cylinder 12
It does not lower the adhesive strength between the substrate and the insulating support member 14 and further does not increase the number of components and the number of assembly steps. Therefore, it is possible to provide a cathode ray tube having high operation characteristics and high reliability at low cost.

The cathode support structure and the cathode ray tube of the present invention are not limited to the case where the cathode structure having the impregnated cathode base is used, but are similarly applicable to the case where the cathode structure having the oxide cathode base is used. It is.

[0041]

As described above, according to the cathode support structure for a cathode ray tube of the present invention, the thermal deformation of the first grid can be corrected with good reproducibility based on the constituent material of the cathode holder. Therefore, according to the cathode ray tube of the present invention having such a cathode support structure, it is possible to stably maintain the color tone balance from the initial stage of turning on the power without causing a decrease in reliability, the number of parts, and an increase in the number of manufacturing steps. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of a cathode support structure for a cathode ray tube of the present invention and an example of an electron gun assembly using the same.

FIG. 2 shows an impregnation type ₂ used for the cathode support structure shown in FIG.
It is a figure which shows one structural example of a cathode structure in partial cross section.

FIG. 3 is a partial cross-sectional view showing a configuration example of a conventional cathode support structure for a cathode ray tube and an electron gun structure using the same.

FIG. 4 is a partial cross-sectional view showing another example of a conventional cathode support structure for a cathode ray tube and an electron gun assembly using the same.

[Explanation of symbols]

 A: electron gun structure B: cathode support structure 10: first grid 11: metal support frame 12: cathode holding cylinder 13: heater connector support member 14: insulating support 15: cathode Structure 16 Cathode sleeve 17 Heater 21 Impregnated cathode base 22 Cathode holder 22a Cathode holder 22b located at the center 22b Cathode holder located outside

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Eiichiro Uda Inventor Eighthro Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture F-term in Toshiba Yokohama Office 5C031 DD04 DD07 DD08 DD15 5C041 AA03 AB03 AC45

Claims (6)

[Claims] 1. A support frame, an insulating support fixedly arranged in the support frame, a heater fixing terminal fixed to the insulating support, and in-line in the support frame via the insulating support. A plurality of cathode holding cylinders arranged, a plurality of cathode holders each having a cathode holder mounted in the plurality of cathode holding cylinders, a plurality of cathode bases are installed on the upper end of the cathode sleeve arranged in the cathode holder In a cathode support structure of an in-line type comprising a cathode structure, a metal material having a larger coefficient of thermal expansion than the cathode holders located on both outer sides of the cathode holders of the plurality of cathode structures. A cathode support structure for a cathode ray tube, comprising: 2. The cathode support structure for a cathode ray tube according to claim 1, wherein the cathode holder located at the center has a thermal expansion coefficient 1.6 to 2.4 times the thermal expansion coefficient of the cathode holders located at both outer sides. A cathode support structure for a cathode ray tube, characterized in that: 3. The cathode support structure for a cathode ray tube according to claim 1, wherein the cathode holder located at the center is made of an Fe—Ni alloy, and the cathode holders located at both outer sides are made of Fe.
-A cathode support structure for a cathode ray tube, comprising a Ni-Co alloy. 4. The cathode support structure for a cathode ray tube according to claim 1, wherein the cathode structure has the impregnated type cathode base. 5. The cathode support structure for a cathode ray tube according to claim 1, wherein the cathode assembly has the cathode substrate of an oxide type. 6. A cathode ray comprising an envelope constituted by a panel, a funnel, and a neck, a phosphor film formed on an inner surface of the panel, and an electron gun assembly disposed in the neck. In the tube, the electron gun assembly is disposed above the support frame in the cathode support assembly according to any one of claims 1 to 5, and has an electron beam passage hole. A cathode ray tube having a first grid.