JPH05166458A - Assembly method for electron gun - Google Patents

Abstract

PURPOSE:To provide a method whereby an electron gun with small unevenness of cut off voltage can easily be assembled. CONSTITUTION:The first grid 12 and a d12 spacer 13 are secured to an insulator 11. A plate thickness tG1, diameter phiG, and a distance d12 of the first grid 12 are measured to substitute these values for EKC0proportional phiG1<a>/(tG1<b>.d01<c>.d12<d>), and a distance d01 necessary for obtaining desired cut off voltage EKC0 is obtained. Thereafter, based on this distance d01, an internal sleeve 15, that is, a cathode is welded. Consequently, the plate thickness tG1, diameter phiG1, distance d01 and the distance d12 are different a little in each unit, but the cut off voltage EKCO is fixed in any unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of assembling an electron gun including at least a cathode, a first grid and a second grid.

[0002]

2. Description of the Related Art In order to facilitate control of three electron beams in a color picture tube, the electron gun must have a cutoff voltage set accurately for each cathode. The cut-off voltage E _KC0 is the thickness and diameter of the first grid tG ₁ and φG ₁ , respectively, the distance between the cathode and the first grid is d ₀₁ , and the distance between the first grid and the second grid is Where d ₁₂ , a, b, c and d are constants, E _KC0 ∝φG ₁ ^a / (tG ₁ ^b · d ₀₁ ^c · d ₁₂ ^d ) is expressed.

On the other hand, in order to assemble an electron gun, conventionally, after all the grids have been beaded, the cathode is finally fixed. At this time, the distance d ₀₂ between the cathode and the second grid is measured by a measurement method such as an air micro system, and the plate thickness of the second grid is set to tG ₂ , and d ₀₂ = d ₀₁ + d ₁₂ + tG ₁ + tG ₂ , The distance d ₀₁ for obtaining the desired cutoff voltage has been determined.

[0004]

However, as is clear from the above equation, the value of the distance d ₀₁ includes all other dimension tolerances, and it is necessary to accurately set the cutoff voltage. I can't. For this reason, in the electron gun with a severe dimension used for a cathode ray tube for business use, lot-leading is performed in which parts are extracted from a lot and then assembled, which increases the assembly cost.

[0005]

A method of assembling an electron gun according to claim 1, wherein a distance d ₁₂ between the first grid 12 and the second grid, or a distance between the cathode 15 and the first grid 12 is provided. fixing d ₀₁ and the first grid 12
With measuring the plate thickness tG ₁ and diameter [phi] G _1, the distance d when ₁₂ first fixing the measure this distance d _12, the distance second case of this distance d ₀₁ fixing the d ₀₁ And the desired cutoff voltage E _KC0 from the plate thickness tG ₁ , the diameter φG ₁ , the distance d ₀₁ and the distance d _12.
Determining the distance d ₀₁ in the first case and the distance d ₁₂ in the second case,
In the first case, the distance between the cathode 15 and the first grid 12 is fixed based on the determined distance d ₀₁ , and in the second case, the first distance is determined based on the determined distance d ₁₂ . Fixing the distance between one grid 12 and the second grid.

In the method of assembling the electron gun according to a second aspect, a step of fixing the distance d ₁₂ between the first grid 12 and the second grid, and a plate thickness tG of the first grid 12 after the fixing.
Measuring a _first and diameter [phi] G ₁ and the distance d _12,
In order to obtain a desired cutoff voltage E _KC0 from the plate thickness tG ₁ , the diameter φG ₁ , the distance d ₀₁ between the cathode 15 and the first grid 12, and the distance d ₁₂ , the distance d
_{The method includes} a step of determining ₀₁ and a step of fixing the distance between the cathode 15 and the first grid 12 based on the determined distance d ₀₁ .

[0007]

In the method of assembling the electron gun according to the present invention, the plate thickness t is one of the parameters that determine the cutoff voltage E _KC0.
After fixing and measuring three parameters of G ₁ , diameter φG ₁ , distance d ₀₁ and distance d ₁₂ , the remaining one parameter, distance d ₀₁ or in order to obtain the desired cutoff voltage E _KC0 Either one of the distances d ₁₂ is determined.

Therefore, even if there are variations in the three initially fixed parameters, these variations can be corrected by the remaining one parameter, and the variations in the cutoff voltage E _KC0 can be corrected by the remaining one parameter. It is possible to suppress only the variation due to fixation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, the first grid 12 and the metallic d ₁₂ spacers 13 located on both sides of the first grid 12 are fixed to one surface of the insulator 11 made of ceramic or the like by brazing or the like. Then, the outer sleeve 14 is fixed to the other surface of the insulator 11 by brazing or the like.

The second grid (not shown) is formed on the surface of the d ₁₂ spacer 13 opposite to the insulator 11 in a later step.
Weld by laser welding or resistance welding. Therefore, when the step between the surfaces of the d ₁₂ spacer 13 and the first grid 12 on the side opposite to the insulator 11 becomes the distance d ₁₂ , and the first grid 12 and the d ₁₂ spacer 13 are fixed to the insulator 11. Thus, the distance d ₁₂ is fixed.

Next, in this state, the plate thickness tG ₁ of the first grid 12, the diameter φG ₁ and the distance d ₁₂ are measured using a measuring instrument. Then, by substituting these values into the above equation, the distance d ₀₁ required to obtain the desired cutoff voltage E _KC0 is calculated.

Next, the inner sleeve 15 sprayed with oxide, that is, the cathode is inserted into the outer sleeve 14, and the upper surface of the first grid 12, that is, the side opposite to the insulator 11 of the first grid 12 is reached from the inner sleeve 15. This distance is compared with the distance d ₀₁ while the distance is measured by a measurement method such as an air micro method. Then, the outer sleeve 14 and the inner sleeve 15 are welded by laser welding or resistance welding at a position where the measured distance is d ₀₁ .

Thereafter, as described above, the second grid (not shown) is welded to the surface of the d ₁₂ spacer 13 opposite to the insulator 11. In addition, beading of all grids will be performed.

In this embodiment as described above, the outer sleeve 14
The thickness t of the unit with the inner sleeve 15 welded inside
G _1, the diameter [phi] G _1, the distance d ₀₁ and the distance d ₁₂ is but slightly different for each unit, the cut-off voltage E _KC0 is constant for any of the units.

As a result, the assembly yield of the cathode ray tube is significantly improved, tolerances of each component and assembly can be allowed to a considerable extent, and the above-mentioned lot advance is not necessary, so that the assembly cost is significantly increased. Can be reduced.

In the above embodiment, the d ₁₂ spacer 1
Since the inner sleeve 15 is welded to the outer sleeve 14 after fixing 3 to the insulator 11, the variation of the cutoff voltage E _KC0 is corrected at the distance d _01.
After welding 5 into the outer sleeve 14, d ₁₂ spacer 13
Fixed to the insulator 11 and cutoff voltage E at a distance d ₁₂
You may correct the variation of _KC0 .

[0018]

In the method of assembling the electron gun according to the present invention, the plate thickness and diameter of the first grid, the distance d ₀₁ between the cathode and the first grid, and the distance d between the first grid and the second grid. _{Even if} 3 out of ₁₂ have variations, the remaining 1
Since the variation of the cutoff voltage can be suppressed only by the variation due to the fixing of one, it is possible to easily assemble the electron gun having the less variation of the cutoff voltage.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an embodiment of the present invention.

[Explanation of symbols]

12 1st grid 13 d ₁₂ spacer 15 inner sleeve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Daichi Imabayashi 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (2)

[Claims] 1. A step of fixing a distance d ₁₂ between a first grid and a second grid or a distance d ₀₁ between a cathode and the first grid, and a plate thickness and a diameter of the first grid. while measuring the distance d in the case ₁₂ first fixing the measure this distance d _12, the distance second case of this distance d ₀₁ fixing the d ₀₁
And in order to obtain a desired cutoff voltage from the plate thickness, the diameter, the distance d ₀₁ and the distance d ₁₂ , the distance d ₀₁ is determined and the second In the case of, the distance d ₁₂
And fixing the distance between the cathode and the first grid based on the determined distance d ₀₁ in the first case, and to the determined distance d ₁₂ in the second case. Fixing the distance between the first grid and the second grid based on the above. And fixing the distance d ₁₂ between the wherein the first grid and the second grid, and measuring the fixed plate thickness and diameter of the first grid and the distance d ₁₂ after the Determining the distance d ₀₁ in order to obtain a desired cut-off voltage from the plate thickness, the diameter, the distance d ₀₁ between the cathode and the first grid and the distance d _12; Fixing the distance between the cathode and the first grid based on ₀₁ .