JP3505994B2 - Manufacturing method of color cathode ray tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a color cathode ray tube, and more particularly to a method of aligning a shadow mask structure with a front panel.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 1, a color cathode ray tube includes a panel 2 having a phosphor screen surface 1 and a shadow mask 3 arranged so as to face the phosphor screen surface 1.
And a frame 4 for holding the shadow mask 3 fixedly.
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 spring 5 and the panel pins 6 are coupled to fix the panel 2 and the shadow mask structure.

Phosphor screen 1 and shadow mask 3
The distance q (q value) between and is a dimension that determines the phosphor matrix arrangement on the phosphor screen surface 1 and the like, and has an important influence on the quality of the color cathode ray tube such as color purity and color reproducibility. It is one of the parts dimensions.

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

The distance Hp is determined by fixing the panel 2 and the panel pin 6 when the panel 2 is manufactured. Therefore, the distance q is generally adjusted by adjusting the distance Hm.

There are roughly two methods of adjusting the distance Hm. In the case of a shadow mask having an open surface of a normal curved surface, a spring 5 is welded to the frame 4 in advance and then the shadow mask 3 is attached to the frame 4.
Are welded together to form a shadow mask structure, and the spring 5 and the panel pin 6 are fitted together.
And the distance q is determined. On the other hand, in the case of a tension mask flat surface performs welding of the shadow mask 3 and the frame 4 above, to adjust the distance Hm by then adjusting the welding position of the spring 5. This is frame 4
When the shadow mask 3 is stretched and welded by applying tension thereto, if the spring 5 is fixed first, it will be an obstacle to the welding of the shadow mask 3, so it is necessary to fix the spring 5 later. Is.

[0007]

In the manufacture of tension mask flat surface [0005] Since the setting of the distance Hm, the distance Hp have been made on the assumption that the center of the design value,
The dimensional variation of the distance Hp directly becomes the dimensional variation of the distance Hm and the distance q. Due to manufacturing, the dimensional accuracy of the distance Hp is limited to ± 0.2 [mm].

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

As a method of improving the accuracy of the distance q,
For example, as described in Japanese Patent Application Laid-Open No. 6-36698, a spring having a discard hole larger than the outer diameter of the panel pin at its 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 the shadow mask structure to the panel pin by resistance welding a centering plate provided with a fitting hole that matches the pin to the discard hole of the spring.

However, with such a method, it is very difficult to adjust the distance q constant over the entire surface of the shadow mask. Considering the flatness of 4 points on the shadow mask, for example, with reference to 4 points at the four corners, the remaining 1 point is about 0.2 [mm] with respect to the plane passing through any 3 points. This is because the deviation cannot be avoided, and simply the four points cannot be uniformly matched with the design value.

Further, in the above method, since all springs require the centering plates for fitting with the panel pins, the number of parts and the number of steps are increased, and since resistance welding is used, thermal deformation during welding is caused. However, there is also a problem that the machining accuracy is large and the processing accuracy is likely to be lowered.

The present invention has been made in order to solve such a problem, and the variation in the distance between the phosphor screen surface and the panel pin plane, which occurs in the panel manufacturing process, is eliminated by assembling the shadow mask structure. An object of the present invention is to provide a method of manufacturing a color cathode ray tube, which can realize the accuracy of the distance q by providing a means for absorbing in the process and improve the working efficiency when assembling the shadow mask structure. To do.

[0013]

A method of manufacturing a color cathode ray tube according to the present invention is provided in a panel side fixture provided on a front panel and a shadow mask structure having a shadow mask on a side facing the panel. In the method of manufacturing a color cathode ray tube, which comprises a step of combining a shadow mask side fixing tool and arranging the shadow mask at a predetermined distance with respect to the phosphor screen surface formed on the inner surface of the panel, replacing phosphor screen to a Jo Tokoro of the virtual plane, upon arranging the shadow mask at a predetermined distance with respect to the virtual plane, a plurality of the paths
Fixture plane formed by the channel-side fixture and the phosphor
Measures the distance Hp to the screen surface at multiple points
However, the virtual plane is determined using the distance Hp.
There are four corners on the phosphor screen.
Determine the point of interest, and place one of them on the diagonal side
The first line segment that connects to another point
A straight line orthogonal to both line segments connecting the two points to be placed
And the intersection point and the front of the first line segment and the straight line
Calculate the intersection of the second line segment and the straight line,
Calculate the point that bisects the third line segment that connects the two intersections
Then, pass through the point that divides the line into two parts and cross the third line segment at right angles.
Is defined as the virtual plane (claim 1).

[0014] Thus, once replaced with the phosphor screen with a predetermined virtual flat surface having a predetermined curvature, or, in the phosphor screen of the reality deviation from a design value occurs Since the curvature and the deviation from the design value can be ignored, the distance q between the phosphor screen surface and the shadow mask can be easily adjusted.

[0015]

Since the fixture plane is already determined when the panel is manufactured, the virtual plane can be clearly defined by using the distance to the phosphor screen surface with respect to the fixture plane as described above. .

[0017]

By aligning the shadow mask by regarding the virtual plane obtained by the above calculation method as a virtual phosphor screen surface, the deviation of the distance q from the design value can be reduced over the entire shadow mask. can do.

Further, in the invention according to claim 1, after fixing the shadow mask side fixing tool at a predetermined position on the outer side surface of the shadow mask structure, the panel side fixing tool and the shadow mask side fixing tool are combined. By doing
The shadow mask is arranged at a predetermined distance from the virtual plane (claim 2 ).

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

In the invention according to claim 2 , the distance hp between the virtual plane and the fixture plane is calculated at the installation position of the shadow mask side fixture, and the phosphor screen surface and the shadow mask are calculated. A desired distance q between and is subtracted from the distance hp to be a distance hm, and the shadow mask side fixing tool is fixed to a position on the outer surface of the shadow mask structure at the distance hm from the shadow mask. It is characterized in that (claim 3 ).

Since the distance from the fixture plane to the virtual plane can be calculated at any position, the shadow mask side fixture can be 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.

Further, in the invention according to claim 3, wherein the fluorescent screen is to have a curvature radius of 4000 mm. To infinity, and the shadow mask structure, in addition a predetermined tension to the shadow mask It is of a tension mask type fixed to a frame by means of a frame (claim 4 ).

Further, in the invention according to claim 4 , fixing the shadow mask side fixing tool to the shadow mask structure is performed by laser welding in three or more welding regions per one shadow mask side fixing tool. It is performed, and in each of the welding regions, a welding orbit circle composed of eight or more welding points is formed (claim 5 ).

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

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION A part of the method for manufacturing a color cathode ray tube according to the present invention, which relates to alignment of a shadow mask structure, will be described below. In this embodiment, the phosphor screen has a flat surface or curvature, and the shadow mask is described as an example a color cathode ray tube tension mask type a flat surface. The manufacturing process other than the assembling process of the shadow mask structure is the same as the conventional manufacturing process, and thus the description thereof is omitted.

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

Here, since the control point of the distance q is set at the position where the highest accuracy is required in the product, it 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 are four corners at a distance of 170 mm in the diagonal axis direction from the center point of the panel. Hereinafter, the “management point” in the present embodiment refers to the above-mentioned 4 points.

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

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

As shown in FIG. 3, the 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 respectively Hp.
1 to Hp4, and the line segment connecting Z1 and Z3 is B1, Z2
Let B2 be the line segment that connects Z4 and Z4. A straight line B3 orthogonal to both the line segments B1 and B2 and their intersections P1 and P2
Is calculated and R is a line segment connecting the intersection points P1 and P2. A plane that passes through a point that bisects the line segment R and is orthogonal to the line segment R is a virtual plane (not shown) according to the present invention.

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

Next, as shown in FIG. 4, the virtual plane 8 thus obtained is considered as a virtual phosphor screen surface, and the virtual plane 8 and the shadow mask 3 are parallel to each other with a distance q. Align the shadow mask so that it is placed. In order to realize the designed distance q at any place on the shadow mask, it is necessary to fix the shadow mask 3 in a plane parallel to the virtual plane 8 that keeps the designed distance q. 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 set. Calculated. This distance h
Let p be hp1, hp2, and hp3, respectively. Distance hp
1 to hp3 is the distance hm calculated by subtracting the distance q.
1, hm2, hm3, this distance hm1 to hm3
Gives the distance Hm at each position of the three spring holes 41-43.

After fixing the springs 5 to the frame 4 so that the distances between the centers of the spring holes 41 to 43 and the shadow mask 3 are hm1 to hm3, the panel pins 6 are fitted into the respective spring holes to fit the shadow mask. By fixing the structure and the panel 2, it is possible to realize the distance q having 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.
Since it was 15 [mm], the maximum is ± 0.35 [mm]
Some variation in the distance q was unavoidable. On the other hand, according to the present invention, by optimizing the distance Hm and absorbing the variation in the distance Hp, the accuracy of the distance q can be improved to about ± 0.05 [mm] in calculation.

Finally, when the shadow mask is aligned, the frame 4 and the spring 5 are laser-welded. In conventional resistance welding, a force of about 400 [kg] was applied to the work piece during welding, so deformation due to strain due to this force and thermal strain due to welding heat would occur, and processing variations during welding would increase. However, the highly accurate distance q could not be realized. According to the laser welding, the thermal deformation of the material due to the heat generated at the time of welding like the conventional resistance welding and the processing distortion due to the sandwiching of the welding electrode are reduced, and the processing accuracy can be improved.

Further, in order to obtain sufficient welding strength, FIG.
As shown in, the welding area 61 per spring is 3
It is preferable to employ multi-point welding in which there are eight or more welding spots 72 on a welding orbit circle 71 of φ5 to 8 [mm] for each welding region, as shown in FIG. 7. By such a laser welding method, the processing accuracy at the time of welding can be improved to ± 0.05 [mm].

By improving the alignment accuracy of the shadow mask and the welding accuracy as described above, the design accuracy of the distance q is ±
The manufacturing yield for 0.1 [mm] is
It was possible to improve from [%] to 98 [%].

[0040]

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

[Brief description of drawings]

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

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

FIG. 6 is a plan view of a spring.

FIG. 7 is an enlarged view of a welding region of a spring.

[Explanation of symbols]

1 Phosphor screen surface 2 panels 3 shadow mask 4 frames 5 springs 6 panel pins 7 panel pin plane 8 virtual planes

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-7504 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 9/18 H01J 29/02

Claims (5)

(57) [Claims] 1. An inner surface of the panel by connecting a panel-side fixture provided on a front panel and a shadow mask-side fixture provided on a shadow mask structure having a shadow mask on a side facing the panel. the method of manufacturing a color cathode ray tube comprising a step of placing at a predetermined distance a shadow mask, replacing the phosphor screen to a Jo Tokoro of the virtual plane with respect to the phosphor screen formed on the upon arranging the shadow mask at a predetermined distance from the virtual plane, the fixture plane formed by a plurality of said panel side fixture
And a plurality of distances Hp between the phosphor screen surface and
And measure the virtual plane using the distance Hp.
What is to be determined, and set arbitrary points at the four corners of the phosphor screen surface.
And one of them and the other diagonally opposite
The first line segment connecting one point and another diagonally located 2
A straight line that is orthogonal to both line segments connecting the points
At the intersection of the first line segment and the straight line and the second line
Calculate the intersection of each line segment and the straight line,
The point that bisects the third line segment that connects the intersection points of
A plane that passes through the point that bisects and is orthogonal to the third line segment
A method of manufacturing a color cathode ray tube, wherein the method is defined as the virtual plane . 2. The shadow mask side fixing tool is fixed at a predetermined position on the outer side surface of the shadow mask structure, and then the panel side fixing tool and the shadow mask side fixing tool are coupled to each other, so that the shadow mask side fixing tool is connected to the virtual plane. The method of manufacturing a color cathode ray tube according to claim 1 , wherein the shadow masks are arranged with a predetermined distance therebetween. 3. A desired distance q between the phosphor screen surface and the shadow mask is calculated by calculating a distance hp between the virtual plane and the fixture plane at an installation position of the shadow mask side fixing tool. Is the distance hm
The method of manufacturing a color cathode ray tube according to claim 2 , wherein the shadow mask side fixture is fixed to the outer surface of the shadow mask structure at a position hm from the shadow mask. 4. The surface of the phosphor screen is 4000
[Mm] have a radius of curvature to infinity, and the shadow mask structure is to claim 3, characterized in that the tension mask type fixed to the frame by adding a predetermined tension to the shadow mask A method for manufacturing the described color cathode ray tube. 5. The fixing of the shadow mask side fixture to the shadow mask structure is performed by laser welding in three or more welding regions per one of the shadow mask side fixtures, and The method for manufacturing a color cathode ray tube according to claim 4 , wherein a welding orbit circle composed of eight or more welding points is formed in each of the welding regions.