JPS6228538B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a color picture tube.

In color picture tubes, it is necessary to strictly define the positional relationship between the shadow mask and the phosphor coated on the panel.

In conventional color picture tubes, in order to maintain an accurate positional relationship between the fluorescent film and the shadow mask, the panel and mask were paired during exposure to form a fluorescent film on the inner surface of the panel. Therefore, the conventional shadow mask cannot currently be replaced with another mask, and has a structure that allows it to be attached and detached from the panel 1, as shown in FIG.

That is, the shadow mask, a frame 6 for reinforcing it, and a spring 4 are fixed by welding or the like, and are suspended from pins 5 embedded in the panel 1 in advance. Therefore, in the conventional method, each time a black coat or phosphor of each color is formed on the inner surface of the panel, the shadow mask 2 must be attached to the panel 1, removed after exposure, developed, and attached many times. In addition to the complexity of putting on and taking off the shadow mask, there is also the inconvenience that if the shadow mask is deformed when it is put on and taken off, it cannot be replaced with another mask.

Therefore, if the work of attaching and detaching the shadow mask described above can be omitted and the positional relationship between the shadow mask and the phosphor can be achieved with high precision,
This makes it possible to significantly reduce manpower and improve efficiency in the production of cathode ray tubes, and is expected to reduce costs.

The present invention has been made with attention to the above points, and an object of the present invention is to provide an inexpensive color picture tube that can omit the work of attaching and detaching the shadow mask and can align the shadow mask and the panel phosphor with high precision. That is.

In order to achieve the above object, according to the present invention,
A reference pattern is set up in advance on the exposure table, and the phosphor is applied to the inner surface of the panel using this pattern as a reference. This makes it possible to avoid the trouble of attaching and detaching the shadow mask during exposure as described above. In addition, using a shadow mask with relatively small positional deviation of the holes, this and the panel after the phosphor coating described above are aligned with high precision using an optical system.
Next, welding is applied to fix the two. Thereby, it is possible to obtain a color picture tube having performance comparable to or better than that of conventional color picture tubes.

The configuration of the present invention is as follows.

A method for manufacturing a color picture tube, comprising the following steps.

(1) Prepare a shadow mask that has a plurality of regularly arranged through holes in its effective surface and at least two reference holes that are disposed on the central Y direction line, that is, on the vertical line, and can be distinguished in shape from the through holes. The process of doing.

(2) A process of preparing a panel that has a striped phosphor pattern on its inner surface and a plurality of springs fixed to the outer periphery of the panel surface.

(3) A step of fixing the panel in a predetermined position by supporting the side wall of the panel with a plurality of support members.

(4) Preparing a plurality of optical systems at predetermined positions so that when the panel is fixed in step (3) above, the central one of the phosphor patterns falls within the field of view. Process.

(5) A step of aligning the reference light and the central one of the phosphor patterns using the optical system, and then fixing the spring and the shadow mask.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 2 is a schematic diagram showing the structure of a shadow mask and panel constituting a color picture tube according to an embodiment of the present invention.

As shown in the figure, the shadow mask 12 according to the present invention has small holes of any shape that can be clearly distinguished from other holes within the effective surface of the mask (an area where there are many holes that are involved in an image when used as a picture tube). is provided, and this small hole serves as a reference hole 15 for alignment with the phosphor 13 formed on the surface of the panel 11. The reference hole 15 exists on the y-direction line at the center of the mask,
Two (or more) holes are drilled as far apart as possible within the effective surface. On the other hand, the phosphor is
As mentioned above, a reference pattern is set in advance on the exposure table, and the phosphor is coated on the inner surface of the panel using this as a reference.By regulating the position of the panel 11 during this exposure, it is possible to accurately coat the inner surface of the panel. Can be applied. Next, aluminum (Al) is vapor-deposited, and the L-shaped spring 14 is attached with high precision. In this way, the shadow mask 11 and the panel phosphor 13 are each manufactured separately.

The reason why the reference hole is provided within the effective surface in the present invention is as follows. That is, the holes in the shadow mask are usually made by etching, and the current situation is that the relative variation in the hole position due to the etching holes is about ±1 to 2 μm even on the effective surface. When a reference hole is provided outside the effective surface, since there are no holes in the vicinity, new etching solution is constantly applied, resulting in excessive etching and variations in hole size. The reference hole center position may vary by ±3 to 4 μm with respect to the hole center in other effective surfaces.

That is, since there are many holes to be drilled in the effective surface, these holes and the reference holes to be formed in the effective surface are etched by a mixture of the etching solution degraded by etching and the new etching solution. . Therefore, the etching speed is slower when etching is performed using this mixed solution than when etching is performed using only the new etching solution.

On the other hand, when the reference hole is to be formed outside the effective surface, there is no other hole to be drilled near the reference hole, so new liquid is always present in that area while the reference hole is being formed. There will be an excess supply. Therefore, if you try to form a reference hole outside the effective surface, it will be more difficult to form a reference hole than in the effective surface.
Etching speed increases.

Further, since etching of a normal shadow mask is carried out in an assembly line operation, the etching solution may stagnate, and the injection angle of the new etching solution onto the surface of the shadow mask may change from time to time. Therefore, the holes formed in the shadow mask are not necessarily etched axially symmetrically with respect to the central axis of the hole.
The hole will be slightly biased. This causes relative variations in hole position due to etching.

If it is attempted to provide the reference hole outside the effective surface, the etching rate will be higher than when the reference hole is provided within the effective surface for the reasons mentioned above. Therefore, when forming a reference hole by etching, the relative variation in the position of the reference hole (proportional to the etching bias) is smaller than when it is formed outside the effective surface. It becomes larger than when forming.

Note that the above-mentioned relative variation in hole position (within the effective surface: ±1 to 2 μm, outside the effective surface: ±3 to
4 μm) is an actual measured value.

As is clear from the above, if the reference hole is provided within the effective surface, the variation in hole position due to etching can be reduced to about ±1 to 2 μm, and the accuracy when aligning with the phosphor can be improved. Because it is possible.

FIG. 3 shows an example of a so-called stripe-type shadow mask in which a fluorescent film is formed in stripes. A small reference hole 15 that can be clearly distinguished from the regularly arranged through holes 16 is bored in the center of the mask in the direction of the long hole.

Next, the alignment of the shadow mask hole and the panel phosphor will be described in detail with reference to FIG. 4.

The shadow mask 12 produced through the above steps is adsorbed on a suction plate 18, and then the panel 11 to which the spring 14 is fixed in advance and coated with a phosphor is supplied. In this case, various methods can be considered for attracting the shadow mask, such as electromagnetic attraction.

In addition, the position regulation of the panel 11 in this case has the same accuracy as the position regulation on the exposure table (not shown) described above, and as shown by P in the figure, the two sides of the panel forming approximately 90 degrees are The panel 11 is held based on several of the points. Next, the panel presser 19 is adjusted in advance so that the gap between the shadow mask 12 and the panel 11 is mechanically determined to a regular size, and the panel holder 19 is adjusted in advance so that the gap between the shadow mask 12 and the panel 11 is mechanically determined. 11 is fixed.

The reference hole of the supplied shadow mask 12 and the phosphor at the center of the panel are respectively placed within the fields of view of the paired optical systems A ₁ , A ₂ ; B ₁ , B ₂ whose optical axes have been aligned in advance.

Here, the principle that the phosphor at the center of the panel falls within the field of view of the optical system will be explained.

First, a method for forming a phosphor pattern will be described. As shown in FIG. 4, the panel surface coated with the phosphor is supported at three points, for example, on the side wall of the panel ("P" in the figure indicates this support). The positioning accuracy by this three-point support is ~10 μm. Furthermore, the pattern width and pattern pitch of the phosphor pattern are the same as the pattern width and pattern pitch of the hole shown in FIG. 3, and are each ~100 μm.
m, 400 to 450 μm. Therefore, it can be seen that the above positioning accuracy is sufficient.

The panel surface supported by the panel side wall is exposed to a reference pattern mask provided on an exposure stage, and then the three-point support is released and the panel surface is subjected to development. This completes the formation of the phosphor pattern.

After development, the panel is mounted on the positioning device shown in FIG. 4 with a positioning accuracy of about 10 μm by supporting the side wall of the panel again.

On the other hand, since the optical systems A ₁ , A ₂ , B ₁ , and B ₂ are installed in advance in the center of the positioning device, when the panel is attached to the positioning device, the phosphor pattern in the center is automatically connected to the optical system. It will be located approximately in the center of the field of view.

Further, the shadow mask 12 is attracted to a suction plate 18 and conveyed onto the positioning device, as will be described later. The suction plate 18 is connected to a fine movement device capable of fine movement in the x, y, and θ directions. Therefore, the shadow mask may be moved by this fine movement device to position the reference hole of the shadow mask within the field of view of the optical systems A ₁ and B ₁ .

Next, the A-A optical axis and the B-B optical axis in each optical system are aligned perpendicularly to the panel surface. In the figure, the suction plate 18 is connected to a fine movement device (not shown, for example, a micrometer, etc.) so that it can be moved slightly in the x and y directions, and in the θ direction, the suction plate 18 is located at approximately the center of the suction plate. It can be rotated by a fine rotation device 21 installed in the. Also,
For example, a microscope is used as the optical systems A ₁ , A ₂ and B ₁ , B ₂ .

The positional deviations measured by the optical systems A ₁ , A ₂ ; B ₁ , B ₂ are measured as a ₁ , a ₂ and b ₁ , b _{2 ,} respectively, as shown in FIG. If we take this as the origin, the reference holes 22 and 23 of the shadow mask 12 will be
It can be seen that they have moved by a ₁ − _{a 2} and b ₁ − b ₂ , respectively. In addition, in FIG. 5, a ₁ and b ₁ indicate the amount of positional deviation of each optical system A 1 and B ₁ of the reference holes 22 and 23, respectively, from the center of field of view, and a 2 and b 2 indicate the amount of positional deviation of each optical system A ₁ and B 1 of the reference holes 22 and 23, respectively, and a ₂ and b ₂ indicate the phosphor ( The amount of positional deviation from the center of the field of view of each optical system A ₂ , B ₂ of the striped pattern) 24 is shown. Also, S ₁ , S ₂
indicates the respective viewing centers of the two pairs of optical systems A ₁ , A ₂ ; B ₁ , B ₂ , which are aligned in advance with the center line of the panel phosphor in the y direction or the stripe direction, as described above. As described above, the position of the panel 11 is regulated based on several points P of the two sides of the panel that form approximately 90 degrees. Also, a circular shape
SA ₁ , SA ₂ and SB ₁ , SB ₂ are the optical system
It shows the visual field of A ₁ , A ₂ and B ₁ , B ₂ ,
The vertical axis within the area indicates the center of the visual field of each optical system described above, and the horizontal axis indicates the scale line in the x direction of each visual field.

In this way, the translation component in the x direction is {(a ₁ − a ₂ ) + (b ₁ − b ₂ )}/2, and the rotation component in the θ direction (around the C-C axis in Figure 4) is Knowing {(a ₁ − a ₂ ) − (b ₁ − b ₂ )}, by this,
By slightly moving the shadow mask suctioned to the suction plate in each direction, it is possible to precisely align the reference hole and the panel phosphor. In addition, y
Regarding the direction, in this embodiment using a stripe type shadow mask, very precise fine adjustment is not required. The reason is as follows.

In other words, the phosphor pattern is striped and y
It is parallel to the axial direction and is not divided in the middle.
The length of this stripe is on the order of cm. For example, if the length of the stripe is set to be sufficiently larger than the width of the effective surface of the shadow mask in the y-axis direction, there is no practical problem even if there is a positioning error of about 100 μm in the y-axis direction. The point is that the length of the stripes of the phosphor pattern should be given a margin to the extent that the electron beam passing through the shadow mask always reaches the surface of the phosphor pattern.

Next, as shown in Fig. 4, the springs 1 at the four corners are
4 and the shadow mask 12 are welded together. Adsorption plate 1
Since 8 serves as an electrode on one side, the welding operation can be easily performed after alignment.

In addition, with this alignment method, even if aluminum (Al) is vapor-deposited, the phosphor can be observed from below, so no problems will occur, and there is no need to create a special phosphor. It is.

In addition, in the embodiment described above, an example was explained in which a combination of a flat plate mask and a flat plate panel was used, but the present invention is not limited to this shape. It is also applicable to combinations of masks and curved panels.

As described above, according to the present invention, the problem of deformation of the shadow mask is eliminated by omitting the work of attaching and detaching the shadow mask and making it possible to precisely align the mask and the panel phosphor. It is expected to improve the efficiency of the manufacturing process, improve the quality and performance of products, and reduce costs, and the effects will be significant when put into practical use.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a conventional color picture tube, FIG. 2 is a diagram showing the structure of a color picture tube according to an embodiment of the present invention, and FIG. 3 is a part of a shadow mask according to the present invention. FIG. 4 is a diagram showing the process of aligning the shadow mask and the panel, and FIG. 5 is a diagram for explaining the alignment. In the figure, 11... Panel, 12... Shadow mask, 13... Fluorescent surface, 14... Spring, 15... Reference hole, 16... Through hole, 17... Effective surface, 18... Adsorption plate, 19 ...Panel presser, 2
0...Movable mounting device, 21...Fine rotation device,
A ₁ , A ₂ ; B ₁ , B ₂ ...optical system.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a color picture tube, characterized by comprising the following steps. (1) A step of preparing a shadow mask having a plurality of regularly arranged through holes in its effective surface and at least two reference holes that are disposed on a vertical line in the center and can be distinguished in shape from the through holes. (2) A process of preparing a panel that has a striped phosphor pattern on its inner surface and a plurality of springs fixed to the outer periphery of the panel surface. (3) A step of fixing the panel in a predetermined position by supporting the side wall of the panel with a plurality of support members. (4) Preparing a plurality of optical systems at predetermined positions so that when the panel is fixed in step (3) above, the central one of the phosphor patterns falls within the field of view. Process. (5) A step of aligning the reference hole and the central one of the phosphor patterns using the optical system, and then fixing the spring and the shadow mask.