JPH11260258A - Manufacture of color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the accuracy of the distance between a phosphor screen surface and a shadow mask, in an assembly process of a shadow mask structure. SOLUTION: This manufacturing method of a color cathode-ray tube arranges a shadow mask by separating it from a phosphor screen surface 1 by a distance (q), by combining a panel pin 6 formed on a front panel 2 with a spring 5 formed on a shadow mask structure which has a shadow mask 3 on the opposite side to the panel 2. At that time, the phosphor screen surface 1 is replaced with a predetermined virtual plane 8 that is a perfect plane, and thus the shadow mask 3 is arranged by separating it from the virtual plane 8 by just the distance (q).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a color cathode ray tube, and more particularly to a method for aligning a shadow mask structure with a front panel.

[0002]

2. Description of the Related Art In general, as shown in FIG. 1, a color cathode ray tube comprises a panel 2 on which a phosphor screen surface 1 is formed, and a shadow mask 3 disposed opposite to the phosphor screen surface 1.
And a frame 4 for fixedly holding the shadow mask 3.
Spring 5 (shadow mask side fixture) on the outer surface of
However, three or more panel pins 6 (panel-side fixtures) are provided on the inner surface of the panel 2, and the panel 2 and the shadow mask structure are fixed by connecting the spring 5 and the panel pins 6.

[0003] Phosphor screen surface 1 and shadow mask 3
Is a dimension that determines the arrangement of the phosphor matrix on the phosphor screen surface 1 and the like, and has an important effect on the quality of the color cathode ray tube such as color purity and color reproducibility. This is one of the component dimensions.

The distance q is, as shown in FIG. 1, a distance Hp between a panel pin plane 7 (fixer plane) passing through the center of the panel pin 6 and parallel to the phosphor screen surface 1 and the phosphor screen surface 1; It is determined by the relationship between the panel pin plane 7 and the distance Hm between the shadow mask 3. Here, the panel pin plane 7 is uniquely determined when three panel pins 6 are provided, and is a plane determined by three of the four or more panel pins 6.

Since the distance Hp is determined by fixing the panel 2 and the panel pins 6 at the time of manufacturing the panel 2, the adjustment of the distance q is generally performed by adjusting the distance Hm.

The method of adjusting the distance Hm is roughly classified into the following two methods. In the case of a shadow mask having a normal curved opening, a spring 5 is welded to the frame 4 in advance, and then the shadow mask 3 is welded to the frame 4 to form a shadow mask structure, and the spring 5 and the panel pin 6 are fitted. Therefore, the distance Hm and the distance q are determined. On the other hand, in the case of a tension mask having a perfect plane, the distance Hm is adjusted by first welding the shadow mask 3 and the frame 4 and then adjusting the welding position of the spring 5. This is because when the tension is applied to the frame 4 and the shadow mask 3 is stretched and welded, if the spring 5 is fixed first, it will hinder the welding of the shadow mask 3, so the spring 5 is fixed later. It is necessary to do it.

[0007]

In the manufacture of a tension mask having a perfect plane, the distance Hm is determined by the distance Hp.
Is at the center of the design value, the dimensional variation of the distance Hp becomes the dimensional variation of the distance Hm and the distance q as it is. The dimensional accuracy of the distance Hp is limited to ± 0.2 [mm] in manufacturing.

[0008] For this reason, it is becoming difficult for color cathode ray tubes, which are required to have high density and high definition of screens in recent years, to respond to product accuracy. For example, 0.24
In the case of a [mm] pitch stripe phosphor screen tube, the distance q needs an accuracy of ± 0.1 [mm],
In the conventional manufacturing method, the required dimensional accuracy of the distance q cannot be obtained.

As a method for improving the accuracy of the distance q,
For example, as described in Japanese Patent Application Laid-Open No. 6-36698, a spring provided with a discarding hole larger than the outer diameter of the panel pin at the tip is arranged in the shadow mask structure, and after the distance q is adjusted, the panel is adjusted. There is a method of fixing a shadow mask structure to a panel pin by resistance welding a centering plate provided with a fitting hole compatible with a pin to a discard hole of a spring.

However, in such a method, it is very difficult to adjust the distance q over the entire surface of the shadow mask. Considering the flatness of the four points on the shadow mask, for example, based on the four points at the four corners, the remaining one point is about 0.2 [mm] with respect to a plane passing through any three of the four points. This is because it is inevitable that the four points will not be uniformly matched with the design values.

Further, in the above method, since all the springs require a centering plate for fitting with the panel pin, the number of parts and the number of processes are increased, and the resistance deformation is used, so that the thermal deformation during welding is reduced. However, there is also a problem that the processing accuracy is easily reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is intended to reduce the variation in the distance between the phosphor screen surface and the panel pin plane which occurs in the panel manufacturing process. It is an object of the present invention to provide a method of manufacturing a color cathode ray tube capable of realizing the accuracy of the distance q and improving the working efficiency when assembling a shadow mask structure by providing means for absorbing in a process. I do.

[0013]

According to a method of manufacturing a color cathode ray tube of the present invention, a panel-side fixture provided on a front panel and a shadow mask structure having a shadow mask on a side facing the panel are provided. A method for manufacturing a color cathode ray tube, comprising: coupling a shadow mask-side fixture with the phosphor mask surface formed on the inner surface of the panel and disposing the shadow mask at a predetermined distance. The phosphor screen surface is replaced by a predetermined virtual plane which is a perfect plane, and the shadow mask is arranged at a predetermined distance from the virtual plane.

As described above, if the phosphor screen surface is replaced with a predetermined virtual perfect plane, an actual phosphor screen surface having a constant curvature or a deviation from a design value is generated. Since the deviation from the curvature and the design value can be ignored, the distance q between the phosphor screen surface and the shadow mask can be easily adjusted.

Further, in the invention according to claim 1, distances Hp between a fixture plane formed by the plurality of panel-side fixtures and the phosphor screen surface are measured at a plurality of locations, and the distance Hp is measured. The virtual plane is used to determine the virtual plane (claim 2).

Since the fixture plane is already determined at the time of manufacturing the panel, the virtual plane can be clearly defined by using the distance to the phosphor screen surface with reference to the fixture plane. .

In the invention according to claim 2, an arbitrary point is defined at each of the four corners of the phosphor screen surface, and one of the points is defined as another point located on the diagonal side. And a straight line orthogonal to both line segments of a second line segment connecting two points located in the other diagonal directions, an intersection of the first line segment and the straight line, and The intersection of the second line segment and the straight line is calculated, and
Calculating a point that bisects a third line segment connecting the two intersections, and determining a plane passing through the bisecting point and orthogonal to the third line segment as the virtual plane ( Claim 3).

The position of the shadow mask is adjusted by regarding the virtual plane obtained by such a calculation method as a virtual phosphor screen surface, thereby reducing the deviation of the distance q from the design value over the entire shadow mask. can do.

Further, in the invention according to any one of claims 1 to 3, after fixing the shadow mask side fixing member at a predetermined position on the outer surface of the shadow mask structure, the panel side fixing member and the shadow mask side are fixed. The invention is characterized in that the shadow mask is arranged at a predetermined distance from the virtual plane by coupling with a fixture (claim 4).

As described above, by adjusting the position of the fixture on the shadow mask side, the distance q between the shadow mask and the virtual plane can be made constant over the entire surface of the shadow mask.

Further, in the invention according to claim 4, a distance hp between the virtual plane and the fixture plane is calculated at an installation position of the fixture on the shadow mask side, and the phosphor screen surface and the shadow mask are calculated. A distance obtained by subtracting a desired distance q between the distance hp and the distance hp,
The shadow mask-side fixture is fixed to a position on the outer surface of the shadow mask structure at the distance hm from the shadow mask (Claim 5).

Since the distance from the fixture plane to the virtual plane can be obtained by calculation at an arbitrary position, the fixture on the shadow mask side is fixed to the shadow mask structure with a distance obtained by subtracting the design value of the distance q from this distance. If
The distance q between the phosphor screen surface and the shadow mask can be kept constant over the entire shadow mask.

In the invention according to claims 1 to 5,
The phosphor screen surface is a quasi-plane having a radius of curvature of 4000 mm to infinity, and the shadow mask structure is a tension mask type in which a predetermined tension is applied to the shadow mask and the shadow mask is fixed to a frame. (Claim 6).

Further, in the invention according to claim 5 or 6, the fixing of the shadow mask-side fixture to the shadow mask structure is performed by using a laser in three or more welding areas per one of the shadow mask-side fixtures. It is performed by welding, and in each of the welding area,
A welding orbit circle composed of eight or more welding points is formed (claim 7).

According to such a method, the fixture can be firmly fixed to the shadow mask structure, and the deformation of the shadow mask structure due to heat during welding can be prevented.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will now be given of a portion of a method for manufacturing a color cathode ray tube according to the present invention, which relates to the positioning of a shadow mask structure. In the present embodiment, a tension mask type color cathode ray tube in which the phosphor screen surface is a perfect plane or a quasi-plane and the shadow mask is a perfect plane will be described as an example. Except for the assembling process of the shadow mask structure, the description is omitted because it is the same as the conventional manufacturing process.

First, as shown in FIG. 2, the distance Hp between the phosphor screen surface 1 and the panel pin plane 7 (fixer plane) is measured at four control points. Note that the distance H
p is the distance measured in the vertical direction from the panel pin plane 7. The measurement is performed by installing a measuring instrument 22 such as a dial gauge on a panel pin flat level plate 21 fixed to the panel pin 6 (panel-side fixture).

Here, the control point of the distance q is set for a position where the highest precision is required in the product, and therefore differs for each product type. For example, in the case of a color cathode ray tube having a size of 41 cm (17 inches), four control points at four corners located at a distance of 170 mm in the diagonal axis direction from the center point of the panel are set. Hereinafter, in the present embodiment, the “management points” refer to the above four points.

Next, based on the four actually measured values of the distance Hp,
A virtual plane is obtained by calculation. Here, the “virtual plane” is a plane obtained by the following calculation from four actually measured values of the distance Hp. If this virtual plane is regarded as a virtual phosphor screen surface and the shadow mask 3 is installed at an interval of a distance q with respect to this virtual plane, the deviation of the distance q from the design value is reduced over the entire surface of the shadow mask 3. Can be suppressed.

FIG. 3 is a conceptual diagram when a virtual plane is obtained by calculation. The measured values Hp1 to Hp4 of the distance Hp at four control points are plotted three-dimensionally with the panel pin plane 7 as a reference plane. is there.

As shown in FIG. 3, the actual measured values of the distances Hp from the four control points a1 to a4 on the panel pin plane 7 to the four points Z1 to Z4 on the phosphor screen surface 1 are represented by Hp, respectively.
1 to Hp4, and the line segments connecting Z1 and Z3 are B1, Z2
A line segment connecting Z4 and Z4 is defined as B2. A straight line B3 orthogonal to both the line segments B1 and B2 and their intersections P1, P2
Is calculated, and a line segment connecting the intersection points P1 and P2 is set to R. A plane passing through a point bisecting the line segment R and orthogonal to the line segment R is a virtual plane (not shown) according to the present invention.

When the points Z1 to Z4 are all on the same plane, that plane is a virtual plane.

Next, as shown in FIG. 4, the virtual plane 8 obtained in this way is considered as a virtual phosphor screen surface, and the virtual plane 8 and the shadow mask 3 are arranged in parallel with a distance q. The shadow mask is positioned so as to be arranged. In order to realize the design distance q at any position on the shadow mask, it is necessary to fix the shadow mask 3 in a plane parallel to the design distance q with respect to the virtual plane 8. This alignment is performed by fixing the shadow mask 3 to the frame 4 and then adjusting the distances hm1 to hm3 between the shadow mask 3 and the centers of the three spring holes 41 to 43.

As shown in FIG. 5, the distance between the center points of the three spring holes 41 to 43 for fitting the panel pins and the virtual plane 8, that is, the distance hp between the panel pin plane 7 and the virtual plane 8 is determined. Obtained by calculation. This distance h
Let p be hp1, hp2, and hp3, respectively. Distance hp
The value obtained by subtracting the distance q from 1 to hp3 is the distance hm, respectively.
Assuming that 1, hm2 and hm3, the distances hm1 to hm3
Gives the distance Hm at each position of the three spring holes 41 to 43.

After fixing the spring 5 to the frame 4 so that the distance between the centers of the spring holes 41 to 43 and the shadow mask 3 becomes hm1 to hm3, the panel pins 6 are fitted into the respective spring holes and the shadow mask is mounted. By fixing the structure and the panel 2, it is possible to realize the distance q with the smallest error with respect to the design value.

In the conventional alignment method, the accuracy of the distance Hp is ± 0.2 [mm] due to variations in panel manufacturing.
The accuracy of the distance Hm is ± 0.
Because it was 15 [mm], ± 0.35 [mm] at maximum
A degree of variation in the distance q was inevitable. On the other hand, according to the present invention, the accuracy of the distance q can be improved to about ± 0.05 [mm] by calculation by optimizing the distance Hm and absorbing the variation in the distance Hp.

Finally, when the positioning of the shadow mask is completed, the frame 4 and the spring 5 are welded by laser. In conventional resistance welding, a force of about 400 (kg) is applied to the workpiece during welding, so deformation due to this force and thermal strain due to welding heat occurs, resulting in large processing variations during welding. , A high-precision distance q could not be realized. According to laser welding, thermal deformation of a material due to heat generated at the time of welding as in conventional resistance welding, and processing distortion due to pinching of a welding electrode are reduced, and processing accuracy can be improved.

Further, in order to obtain a sufficient welding strength, FIG.
As shown in the figure, the welding area 61 per spring is 3
It is preferable to use multipoint welding in which eight or more welding spots 72 are provided on a welding orbit circle 71 of φ5 to 8 [mm] for each welding region, as shown in FIG. By such a laser welding method, the processing accuracy during welding can be improved to ± 0.05 [mm].

By improving the positioning accuracy of the shadow mask and the welding accuracy as described above, the design accuracy of the distance q can be reduced by ±±.
The production yield for 0.1 [mm] is
[%] To 98 [%].

[0040]

As described above, according to the present invention, the accuracy of the distance q can be greatly improved in the process of assembling the shadow mask structure, so that the color cathode ray tube requiring high definition can be produced at a high yield. , Can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view of a color cathode ray tube.

FIG. 2 is a diagram showing how a distance between a panel pin plane and a phosphor screen is measured.

FIG. 3 is a conceptual diagram showing a calculation method of a virtual plane.

FIG. 4 is a perspective view showing a positional relationship between a shadow mask and a virtual plane.

FIG. 5 is a side view showing the positional relationship between the shadow mask and the virtual plane.

FIG. 6 is a plan view of a spring.

FIG. 7 is an enlarged view of a welding area of the spring.

[Explanation of symbols]

 Reference Signs List 1 phosphor screen surface 2 panel 3 shadow mask 4 frame 5 spring 6 panel pin 7 panel pin plane 8 virtual plane

Claims (7)

[Claims] 1. A panel-side fixing device provided on a front panel and a shadow mask-side fixing device provided on a shadow mask structure having a shadow mask on a side facing the panel, and an inner surface of the panel is provided. A method for manufacturing a color cathode ray tube, comprising a step of arranging the shadow mask at a predetermined distance with respect to the phosphor screen surface formed on the phosphor screen, wherein the phosphor screen surface is replaced with a predetermined virtual plane which is a complete plane. And disposing the shadow mask at a predetermined distance from the virtual plane. 2. A method of measuring distances Hp between a fixture plane formed by a plurality of panel-side fixtures and the phosphor screen surface at a plurality of locations, and determining the virtual plane using the distances Hp. The method for producing a color cathode ray tube according to claim 1, wherein 3. An arbitrary point is defined at each of the four corners of the phosphor screen surface, and one of the points is connected to a first line segment connecting another point located diagonally, and A straight line orthogonal to both line segments of the second line segment connecting the two points located in the diagonal directions, and the intersection of the first line segment and the straight line, and the second line segment and the straight line. Are calculated respectively, and a point that bisects a third line segment connecting the two intersections is calculated. A plane passing through the bisecting point and orthogonal to the third line segment is calculated as the virtual 3. The method according to claim 2, wherein the color cathode ray tube is defined as a flat surface. 4. After fixing the shadow mask side fixing member at a predetermined position on the outer surface of the shadow mask structure, the panel side fixing member and the shadow mask side fixing member are connected to each other to form the virtual plane. 4. The method according to claim 1, wherein the shadow mask is arranged at a predetermined distance from the shadow mask. 5. A distance hp between the virtual plane and the fixture plane is calculated at an installation position of the shadow mask-side fixture, and a desired distance q between the phosphor screen surface and the shadow mask is calculated. Is subtracted from the distance hp and the distance hm
5. The method according to claim 4, wherein the fixture on the shadow mask side is fixed to a position on the outer surface of the shadow mask structure at the distance hm from the shadow mask. 6. 6. The phosphor screen surface is 4000
[Mm] to a quasi-plane having a radius of curvature of infinity to infinity, and wherein the shadow mask structure is of a tension mask type in which a predetermined tension is applied to the shadow mask and fixed to a frame. Item 6. The method for producing a color cathode ray tube according to any one of Items 1 to 5. 7. The fixing of the shadow mask-side fixture to the shadow mask structure is performed by laser welding in three or more welding areas per one of the shadow mask-side fixtures, and The method according to claim 5 or 6, wherein a welding orbit circle including eight or more welding points is formed in each of the welding areas.