JP2002352748A - Color picture tube and method for manufacturing cathode support strap - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color picture tube which has a stable cutoff voltage with little dispersion by eliminating the dispersion of the cutoff voltage due to an assembly factor in an electron gun. SOLUTION: Each outside surface of three cathode support cylinders 6r, 6g, and 6b, into which a cathode structure having a cathode is individually inserted, is fixed by using each fixing portion of cathode support straps 7r, 7g and 7b which are formed of a long plate member and have fixing portions at middle portions in the longitudinal direction. In a state with these cathode support cylinders being arranged in a row in the lateral direction, both ends of each cathode strap are embedded and fixed to a pair of insulating support bars 11. Each cathode support straps 7r, 7b for fixing each cathode support cylinder 6r, 6b arranged outside comprises outward extending portions 14, which extend outwardly from a fixed portion and inward bent portions 15, which are bent inwardly from the tips of the outward extending portions up to the portions embedded and is fixed to the insulation support bars.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube having an in-line type three electron gun, and more particularly to an improvement in a cathode support strap for holding a cathode support cylinder of an electron gun on an insulating support rod.

[0002]

2. Description of the Related Art In general, a cathode ray tube comprises a panel portion having a substantially rectangular face plate, a long neck portion having a small diameter, and a substantially funnel-shaped funnel portion connecting the panel portion and the neck portion. An enclosure (glass bulb) is provided. The panel portion has a fluorescent film adhered to the inner surface of the face plate, the electron gun is housed inside the neck portion, and the funnel portion has a deflection yoke mounted on the outer periphery of the joint portion with the neck portion.

The electron gun has a cathode structure for holding a disk-shaped cathode by a cylindrical holder, a heater provided inside the holder of the cathode structure, and a cathode support for inserting the cathode structure therein and fixing the same. A cylinder, a long plate-shaped cathode support strap for holding the cathode support cylinder, and first, second, and third shafts arranged sequentially at positions facing the cathode with their axes aligned.
A grid; and a pair of insulating support bars for supporting the cathode support strap and the first to third grids on both sides in the vertical direction.

The color picture tube is an in-line type 3 described above.
By using an electron gun, the horizontal deflection magnetic field is made into a pincushion shape, and the vertical deflection magnetic field is made into a barrel shape, so that three electron beams can be self-converged (self-convergence), thereby reducing power consumption. . For this reason, color picture tubes using such an in-line type three-electron gun assembly are currently the mainstream color picture tubes for general use.

By the way, a structure for holding a cathode support cylinder with a cathode support strap, for example,
It is disclosed in JP-A-11-307010. FIG. 3 is a schematic diagram showing the configuration, in which an arc-shaped fixing portion formed at a longitudinally intermediate portion of a long plate-shaped cathode support strap 7 is fixed to the outer peripheral surface of a cylindrical cathode support cylinder 6 by welding. I have.

On the other hand, a support structure for the cathode support cylinder 6 in the case of an in-line type three-electron gun is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-255690. FIG. 4 shows the assembled state together with the schematic configuration.
The arc-shaped fixing portions of the cathode support straps 7r, 7g, 7b are welded to the cylindrical outer peripheral surfaces of the cathode support cylinders 6r, 6g, 6b of the electron guns corresponding to blue and green, respectively. Is fixed to the insulating support rod 11. In this case, the width of the insulating support bar 11 is formed narrow because it is necessary to house three electron guns in the neck portion. For this reason, the cathode support cylinder 6 disposed outside
r, 6b, a cathode support strap 7r,
Both ends of 7b are bent obliquely in the center direction, that is, inward, and are fixed to each other at a small interval. The cathode support straps 7r, 7g, 7b are assembled by stacking them on an assembling jig via the spacer 20, and then vertically implanting the upper and lower end portions with a gas burner at 1300-140.
The pair of insulating support rods 11 heated to 0 ° C. and softened is press-fitted and fixed.

[0007] Thereafter, the cathode support cylinders 6r, 6g, 6g, 6g, 6g are arranged so that the center of the opening of the beam passage hole provided in the first grid is aligned with the axis and the surface of the cathode has a predetermined distance from the first grid. The cathode structure is positioned in 6b and fixed by welding.

[0008]

The cathode support straps 7r, 7g, 7b of the conventional color picture tube described above.
When the electron gun is assembled, heat is received by press-fitting a pair of insulating support rods 11 that have been softened by heating. At this time, the outer cathode support straps 7r, 7b arranged in-line
Expands mainly in the longitudinal direction due to heat, and the cathode support cylinders 6r and 6b are moved outward in an inline arrangement. For this reason, the axis of the cylindrical cathode support cylinders 6r and 6b deviates from the axis of the electron beam passage holes formed in the first grid, and when the cathode assembly is welded and fixed in the cathode support cylinders 6r and 6b, This causes the cathode structure to be tilted or deformed, resulting in inaccurate positioning, and variations in the cut-off voltage of each electron gun.

As is well known, in an in-line type color picture tube, it is necessary to assemble the electron guns with high accuracy so that the cut-off voltage of each electron gun is the same in order to obtain a good white screen. It was difficult to suppress the variation of the cutoff voltage due to the above factors at the time of assembling the electron gun.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to eliminate a variation in cut-off voltage due to an assembling factor of an electron gun and to realize a color receiving device capable of realizing a stable cut-off voltage with little variation. It is an object to provide a method for manufacturing a tube and a cathode support strap.

[0011]

The invention according to claim 1 is
Three cathode assemblies each having a disk-shaped cathode and a holder for holding the cathode at a cylindrical end; a heater installed inside the cathode assembly and generating heat when energized; and a cathode assembly inside. Three cylindrical cathode support cylinders, each of which is fixed in a state where the cathode support cylinders are inserted, and a molded long plate member, which has an arc-shaped fixing portion at an intermediate portion in the longitudinal direction, and has a fixing portion of each cathode support cylinder. Three cathode support straps that are engaged with and fixed to the cylindrical outer surface, and a pair of insulating supports that embed and fix each end of the cathode support strap with the three cathode support cylinders arranged in a row. A color cathode-ray tube having a rod, and a pair of cathode support cylinders arranged outside one of the three cathode support cylinders arranged in a horizontal row. The cathode support strap that fixes the cathode support cylinder has an outwardly projecting portion that extends outward from the fixing portion, and an inwardly bent portion that is bent inward from the tip of the outwardly projecting portion to a portion embedded in the insulating support rod. And characterized in that:

According to a second aspect of the present invention, in the color picture tube according to the first aspect, the cathode support straps for fixing the pair of cathode support cylinders arranged outside are three cathode supports arranged in a horizontal line. The projection angle of the outwardly protruding portion with respect to the virtual plane passing through each axis of the cylinder is smaller than the bending angle of the inwardly bent portion with respect to the virtual plane.

According to a third aspect of the present invention, in the color picture tube according to the first or second aspect, the bending angle and length of the inwardly bent portion are adjusted so as to suppress displacement of the cathode support cylinder due to a thermal action. The protrusion angle and length of the outward protrusion are determined.

According to a fourth aspect of the present invention, there is provided a method for manufacturing a cathode support strap, wherein the cathode support strap constituting the color picture tube according to any one of the first to third aspects is formed by embossing. It is.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a cathode support strap, wherein the cathode support strap constituting the color picture tube according to any one of the first to third aspects is formed by cutting and raising. Is the way.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view showing a configuration of an electron gun of a color picture tube according to the present invention.
In FIG. 1, a cathode 1 is formed in a disk shape and is held at one end of a cylindrical cathode sleeve 2. The cathode sleeve 2 is fixed through a thin long plate-shaped cathode strap 4 in a cylindrical cathode holder 3 serving as an envelope formed so as to surround the cathode sleeve 2, and these form a cathode structure. I do.

A heater 5 is provided in the cathode sleeve 2.
Further, a cylindrical cathode support cylinder 6 having a function of fixing the cathode structure is fitted to the outside of the cathode holder 3. The arc-shaped fixing portion of the cathode support strap 7 described above is welded to the outer peripheral surface of the cathode support cylinder 6.

On the other hand, a first grid 8, a second grid 9 and a third grid 10 are arranged on the side facing the cathode 1 with their axes aligned sequentially. Of these, the first grid 8
Controls the electron beam emitted from the cathode 1, the second grid 9 blocks the change in the electric field due to the first grid 8, and the third grid 10 has the function of accelerating the electron beam. Further, the disk-shaped cathode 1 is installed such that the opening of the beam passage hole provided in the first grid 8 and the axis coincide with each other, and a predetermined gap is maintained. Further, the cathode support strap 7, the first grid 8, the second grid 9, and the third grid 10 are integrally fixed by a pair of insulating support rods 11.

In a color picture tube in which three electron guns are arranged in a horizontal line, the cathode support cylinder 6 constituting the electron gun shown in FIG. 1 is positioned at the center as described with reference to FIG. The cathode support cylinder 6g of the electron gun is fixed to the insulating support rod 11 via a cathode support strap 7g extending upward and downward from an arc-shaped fixing portion, but the electron guns located at both ends are fixed. The cathode support straps 7r and 7b are fixed to the insulating support rod 11 via the cathode support straps 7r and 7b whose attachment ends are bent obliquely toward the center, that is, inward.

FIG. 2 is a view showing the detailed structure of the cathode support strap 7b. The cathode support strap 7r has the same shape as the cathode support strap 7b and is symmetrically arranged.
Here, the cathode support strap 7b is formed in a thin long plate shape, an arc-shaped fixing portion 13 is formed at an intermediate portion in the longitudinal direction, and further, from an end of the fixing portion 13 to the outside where the electron guns are arranged in-line. Outer projecting portion 14 projecting obliquely
And an inwardly bent portion 15 which is obliquely bent from the protruding end to the inside where the electron gun is arranged inline. In addition, the inwardly bent portion 15 is provided with the outwardly projecting portion 14.
A part from the protruding end of the cathode support cylinder 6 to the central part of the cathode support cylinder 6 is formed in an arc shape, and the remaining part is formed in a linear shape, and the end part fixed to the insulating support rod 11 is bent and formed in a vertical direction. I have.

Here, the projection angle β of the outwardly projecting portion 14 with respect to the virtual plane 1 passing through the axis of each of the three cathode support cylinders 6r, 6g, 6b arranged in a horizontal line is defined as Bending angle α of bending part 15
Smaller than. Incidentally, the cathode support strap 7b can be formed with high precision by embossing or cutting and raising.

The movement of the cathode support strap 7b constructed as described above when assembling it to the insulating support rod 11 and its suppression will be described below. At the time of assembling the electron gun, the heat received by the press-fitting of the pair of insulating support rods 11 that have been softened by heat is transmitted to the inwardly bent portion 15 and the outwardly projecting portion 14 of the cathode support strap 7b, and these portions are mainly in the longitudinal direction. Thermally expands. Among them, the cathode support cylinder 6 moves in the direction of arrow A due to the thermal expansion of the inwardly bent portion 15. On the other hand, the outwardly projecting portion 14
The cathode support cylinder 6 moves in the direction of arrow B due to the thermal expansion of. These movements are offset directions. Here, if the angle α of the inwardly bent portion 15 with respect to the virtual plane 12 is increased, the amount of movement of the cathode support cylinder 6 in the direction of the arrow A is reduced. In addition, the outward projecting portion 14
When the angle β with respect to the virtual plane 12 is reduced, the amount of movement in the direction of arrow B increases. In this case, the outer protrusion 14
The length L1 and the length L2 of the inwardly bent portion 15 have a relationship of L1> L2, so that the entire length of the cathode support strap 7 is shortened, so that a strong attachment is possible. Become.

Therefore, assuming that a relationship of L1> L2 is provided between the length L1 of the outwardly protruding portion 14 and the length L2 of the inwardly bent portion 15, the length of the inwardly bent portion 15 can be reduced. By providing a relationship of α> β between the angle α with respect to the virtual plane 12 and the angle β of the outward projection 14 with respect to the virtual plane 12, the effect of forming the outward projection 14 on the cathode support strap 7b is achieved. Enhanced. If the dimensions allow, the lengths and angles of L1> L2 and α> β are appropriately determined to determine the length and angle of the movement of the cathode support cylinder 6 in the in-line arrangement direction due to heat. It can be suppressed to substantially zero or a value close to zero.

Thus, according to the present embodiment, the central axis of the cylindrical cathode support cylinder 6 and the first grid 8
Can be positioned, welded, and fixed so that the center axis of the beam passage hole provided in the electron gun coincides with high accuracy, and a color picture tube with less variation in cutoff voltage of each electron gun can be obtained.

[0025]

As is apparent from the above description, according to the present invention, a cathode support strap for fixing a pair of cathode support cylinders arranged outside, of three cathode support cylinders arranged in a row. Is provided with an outwardly protruding portion extending outward from the fixed portion, and an inwardly bent portion which is bent inward from a tip of the outwardly protruding portion to a portion embedded in the insulating support rod. It is possible to provide a color picture tube which can eliminate a variation in cutoff voltage due to the assembling factor and realize a stable cutoff voltage with little variation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electron gun constituting an embodiment of a color picture tube according to the present invention.

FIG. 2 is a side view for explaining the shape of the cathode support strap constituting the embodiment shown in FIG. 1 and expansion and contraction operations by heat.

FIG. 3 is a perspective view showing a shape of a fixing portion of a cathode support strap for holding a cathode support cylinder.

FIG. 4 shows a cathode support cylinder supporting structure when three electron guns are arranged in-line in the horizontal direction.
FIG. 4 is a side view showing an assembled state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cathode 2 Cathode sleeve 3 Cathode holder 5 Heater 6r, 6g, 6b Cathode support cylinder 7r, 7g, 7b Cathode support strap 8-10 1st-3rd grid 11 Insulation support rod 12 Virtual plane 13 Fixed part 14 Outer projection 15 Inward bent part

Claims (5)

[Claims] 1. A three-cathode assembly having a disk-shaped cathode and a holder for holding the cathode at a cylindrical end, and heaters respectively installed inside the cathode assembly and generating heat when energized. And three cylindrical cathode support cylinders each of which fixes the cathode structure in a state inserted therein, and a molded long plate member, which has an arc-shaped fixing portion at an intermediate portion in the longitudinal direction, Three cathode support straps that fix and engage a fixing portion with a cylindrical outer surface of each of the cathode support cylinders; and a state in which the three cathode support cylinders are arranged in a row in a row. And a pair of insulating support rods, each end of which is embedded and fixed, wherein the three cathodes are arranged in a horizontal row in a color picture tube comprising: Among the port cylinders, the cathode support strap for fixing the pair of cathode support cylinders arranged outside is provided with an outer protruding portion extending outward from the fixing portion, and an insulating member provided at a tip end of the outer protruding portion. A color picture tube comprising: an inwardly bent portion bent inward to a portion embedded in the support rod. 2. The cathode support strap for fixing a pair of cathode support cylinders disposed on the outside, wherein the cathode support straps project outward from an imaginary plane passing through respective axes of the three cathode support cylinders arranged in a row. 2. The color picture tube according to claim 1, wherein a projection angle of the portion is smaller than a bending angle of the inward bent portion with respect to the virtual plane. 3. The projection angle and length of the outward projection are determined in accordance with the angle and length of the inwardly bent portion so as to suppress the displacement of the cathode support cylinder due to thermal action. The color picture tube according to claim 1 or 2, wherein 4. A method for manufacturing a cathode support strap, wherein the cathode support strap constituting the color picture tube according to claim 1 is formed by embossing. 5. A method for manufacturing a cathode support strap, wherein the cathode support strap constituting the color picture tube according to claim 1 is formed by cutting and raising.