JPH02123645A - Shadow mask body for color picture tube - Google Patents

Abstract

PURPOSE:To obtain high resolution and improve color purity and lifetime by forming a plurality of laminated shadow mask plates in such a way that the plates are welded at a plurality of porous regions and then pressed for the formation. CONSTITUTION:A shadow mask 22 of large thickness is laminated on the phosphor screen side of a relatively thin-walled shadow mask plate 21 at the side of an electron gun. Slot type through-holes 30 and 31 are provided on the plates 21 and 22 for forming an electron beam passage hole. The through-hole 31 is so formed as to be somewhat larger than the hole 30. After welded at welding portions 32 and 33, the plates 21 and 22 are pressed to have a spherical shape.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is constructed by welding and joining a plurality of shadow mask plates, and has an electron beam passage hole that allows the electron beam to pass to the phosphor screen side in the picture tube. This invention relates to a shadow mask structure for a color picture tube.

[Prior Art] FIG. 9 is a partially cutaway perspective view schematically showing the structure of a shadow mask type force/ray picture tube. In the same figure, (1)
is a funnel-shaped funnel, and a fluorescent screen (3) is formed on the inner surface of a panel (2) sealed to the open end of this funnel (1). A plurality of bins (0) are provided on the side wall of the panel (2), and a shadow mask structure (5) disposed facing the fluorescent screen (3) is supported by the bins (4). (12A).

(12B) and (12G) are electron guns disposed within the neck portion (10) of the funnel (1).

(7) is a shadow mask structure having a spherical shape almost equal to the inner surface shape of the panel (2), and this shadow mask structure (7) is connected to the electron guns (12A) and (12B).
.

Electron beam (13A) emitted from (12G),
It consists of a perforated part having a large number of electron beam passing holes (13) through which electron beams (8B) and (13c) selectively pass, and a non-porous part formed around the outer periphery of this perforated part, that is, a non-porous part. .

(8) is a skirt portion that is bent to be attached to the frame (9), and this skirt portion (8) is fixed to the frame (8) over its entire circumference by, for example, welding at six points. . (10) is a thermal expansion correction mechanism welded to the frame (9), and this thermal expansion correction mechanism (l
O) is provided to correct color shift due to thermal expansion of the shadow mask structure (7) that occurs during operation of the color picture tube.

The thermal expansion correction mechanism (lO) is composed of a bimetal (15) and a spring (11) welded to this bimetal (15).
This spring (11) is composed of the above-mentioned bottle (
4) to move the shadow mask structure (7) to the panel (
2) is held in the relative position. The above shadow mask structure (
5) is composed of a shadow mask structure (7), a frame (9) and a thermal expansion correction mechanism (10).

In the shadow mask second color picture tube having the structure as shown, the electron guns (12A) and (12B) are used.

Electron beam (8A) emitted from (12G), (
[18), (8G) passes through the electron beam passing hole (13) provided in the perforated part of the shadow mask structure (7) and hits the fluorescent screen (3), emitting light in red, green, and blue colors. make the phosphor emit light.

By the way, 1. Normally, the total area of the electron beam passage hole (13) of the shadow mask body (7) is the same as that of the shadow mask structure (1).
7), and most of the electron beams (8A), (8B), and (8G) collide with the non-opening part of the perforated part and heat the shadow mask structure (7). . For example, as a result of measuring the temperature of the shadow mask structure (5) in a 21-inch color picture tube, there was a rise in temperature as shown by curves (A) and (B) in FIG. 1O.

That is, when the temperature of the shadow mask structure (7) was measured under the conditions of a high voltage of 28 kV and a beam current of 1 mA, as shown in the characteristic curve (A) in FIG.
The temperature rises significantly within 30 minutes, reaching saturation in 30 minutes and reaching approx.
A temperature increase of 0°C was observed.

On the other hand, when the temperature of the frame (9) was measured under similar conditions, it was found that the heat capacity of the frame (8) was larger than that of the shadow mask structure (7).
As shown by characteristic curve CB) in Figure 410, the temperature gradually rose and reached a saturated state in about 1 hour.

When such a temperature rise occurs, the shadow mask structure (7) first thermally expands into a dome shape (hereinafter referred to as doming) and protrudes toward the phosphor screen (3), causing color shift (hereinafter referred to as mislanding). ).

That is, as shown in FIG. 11, the shadow mask structure (7), which was in the state shown by the solid line S in the figure before the start of operation, is fixed as a whole with the joint W with the frame (9) as the temperature rises. It then thermally expands toward the phosphor screen (3) in a dome shape as shown by the dotted line Sl. Through this doming,
The electron beam passing hole (13), which was in the normal position indicated by point H in the same figure, moves to point H1, and originally has to reach point P on the phosphor screen (3), for example, the electron gun (12A
The electron beam (6A) from ) reaches point Pi, resulting in a mislanding.

This type of mislanding occurs when the center Z of the fluorescent screen (3)
It is characterized by a shift in the direction of arrow a (arrow a side), and 8 is achieved by causing adjacent phosphors of other colors to emit light and producing a normal color image. Such a phenomenon appears over the entire screen.

This phenomenon occurs when the inner radius of the diagonal axis of panel (2) is 1.
When measured with a 350mm 21-inch color picture tube, the distance was 150m from the central axis Z of the face of panel (2).
The electron beam appears most prominently on long sleeves of 0.05~0.m under the conditions of high voltage 28kV and beam current 1mA.
08 mm, which caused a color shift phenomenon.

On the other hand, when the temperature of the frame (9) gradually increases and approaches the saturated state, due to thermal expansion of the frame (8) itself, the frame (9), which was in the state shown by the solid line F in FIG. 12 before the start of operation, thermally expands in the radial direction as a whole as shown by the dotted line F1. As a result, the shadow mask structure (7), which was in the state shown by the solid line S in the figure before the start of the operation, changed to the frame (
9) moves to point Wl, the whole is displaced in the radial direction as shown by dotted line S2. Due to this displacement, the electron beam passage hole (13), which was in the normal position shown as point H in the figure, moves to point H2, and originally should reach point P on the phosphor screen (3), for example. Electron gun (1
The electron beam (6A) from 2A) reaches point P2,
This results in a false landing.

This type of mislanding is characterized by a shift toward the periphery of the phosphor screen (3) (to the side indicated by the arrow), and other colors in the opposite direction to the phenomenon that appears at the beginning of the operation of the color picture tube described above. This makes it impossible to make the phosphors emit light and produce a normal color image as in the early stages of operation of the color picture tube.

The above phenomena occur continuously while the color picture tube is in continuous operation.

Therefore, it is necessary to correct this.

Conventionally, in order to correct this, various types of thermal expansion correction mechanisms (io) are known that are interposed between the shadow mask structure (7) and the frame (9).

That is, as explained with reference to FIG. 11, doming occurs when the joint W between the shadow mask structure (7) and the frame (8) serves as a fixed point, so it is operated by the thermal expansion correction mechanism (10). The above joint W before starting
If the shadow mask structure (7) is moved to the point W3 shown by the imaginary line, the shadow mask structure (7) that was in the state shown by the solid line S in the same figure before the start of the operation is moved.
moves closer to the electron gun (12A) than in the case shown by the dotted line Sl in the figure, as shown by the virtual line S3. As a result of this movement, the electron beam passing hole (13) that was in the normal position shown as point H in the figure moves to point H3, and the electron beam passing hole (13) that has moved to this point H3 is connected to the electron gun (12A). The electron beam (8A) is directed to the point P on the phosphor screen (3) that it should originally reach, reducing mislanding.

On the other hand, due to an increase in the temperature of the frame (9), the frame (8) was in the state shown by the solid line F in FIG. 12 before the start of operation.
thermally expands as shown by the one-dot line F1, and the electron beam passage hole (13), which was in the normal position shown by point H, moves to point H2.

However, due to the thermal expansion correction mechanism (10), if the shadow mask structure (7) is brought closer to the phosphor screen (3) as shown in virtual 9&S3, the electron beam that was in the normal position shown as point H in the figure is The passage hole (13) moves to point H3, and the electron beam passage hole (13) moved to this point H3 connects to the phosphor screen (3) where the electron beam (BA) from the electron gun (12A) should originally reach. It will be in a position facing the point P above,
Mislandings are reduced.

Since then, such a thermal expansion correction mechanism (lO) has been developed using, for example, bimetal (15).
No. 3-26152, Special Publication No. 44-3547, Special Publication No. 4
Known examples include No. 7-3506 and Special Publication No. 47-40505.

However, as shown in FIG. 13, for example, a screen (1B) consisting of a dark field area (A) and a circular high brightness area (B)
When an image is received, a local part (7a) of the shadow mask structure (7) corresponding to the high brightness part (B) is thermally deformed, and color shift occurs due to local doming. The color shift caused by such local doming can be solved by the conventional thermal expansion correction mechanism (10
), it was impossible to correct it.

In order to solve the problem of color shift due to such local doming, as shown in the paper "Theoretical Study on Local Doming Phenomenon of Shadow Mask Tube" published in the Journal of the Television Society, a shadow mask structure (7) is proposed. It has been theoretically proven that it is effective to reduce the amount of water within the thickness.

However, the shadow mask structure (7) is generally manufactured by a chemical method such as the etching method disclosed in Japanese Patent Publication No. 51-9264.

In this chemical manufacturing method, the shadow mask structure (
7) between the plate thickness (1) and the size (Sv) of the electron beam passage hole (13) through which the electron beam passes, Sv)0.
There is a condition: 8Xt...■, and it is impossible to satisfy this condition and densely form small holes in a thick plate.

In other words, in order to improve the resolution of the 5-color picture tube,
By reducing the setting pitch of the phosphors constituting the phosphor screen (3), the shadow mask structure (7) can perform its color selection function by reducing the electron beam passing holes (1) formed therein.
It goes without saying that the size of 3) must also be made small.

On the other hand, in order to suppress color shift due to thermal deformation of the shadow mask structure (7) and maintain good color purity.

The fact that a thick shadow mask structure (7) is required is as stated in the above-mentioned article in the Journal of the Society of Television Engineers.

However, these two have a clearly contradictory relationship from the above equation 0. Therefore, in order to satisfy both of these requirements, it is extremely difficult to create a small electron beam passage hole (13) in the shadow mask structure (7) made of a single thick plate, as described above. be.

Therefore, as shown in Japanese Patent Application Laid-Open No. 57-138746, a substantially thick shadow mask structure can be obtained by stacking a plurality of thin shadow mask plates and welding them at their outer peripheries. It is proposed to configure (7).

Figures 14 and 15 are from the above-mentioned Japanese Patent Application Publication No. 57-13874.
FIG. 14 is an explanatory diagram showing a method for forming a thick shadow mask structure proposed in Publication No. 6, and first, as shown in FIG. 14,
Two shadow mask plates (21) and (22) with different thicknesses
), and the perforated wire area with each electron beam passage hole (
23A). Non-porous area (24A) on the outer periphery of (23B)
, a positioning hole (25A) formed in (24B),
(25B) and a positioning pin (26) that engages with the positioning jig (27). As a result, 5 the above two shadow mask plates (21). (22) are superimposed and positioned so that their respective electron beam passing holes match. In this state, the two shadow mask plates (21). (22) Their non-porous area (24A)
, (24B), spot welding step 8) or seam welding is performed.

Next, as shown in FIG. 15(a), the electron beam passing holes (13a) and (13b) of the shadow mask plates (21) and (22) that match each other are aligned as shown in FIG. 15(b). After filling it with polyamide resin (29), it is dried with hot air, for example, and this resin (29) is cured to give it sufficient strength. Thereafter, as shown in FIG. 15(C), male and female molds having desired curvatures are used to form a shadow mask for a normal color picture tube.
By press forming, two shadow mask plates (
21), electron beam passage hole (13a) due to variations in slippage and elongation of (22).

(13b) is prevented from shifting. Then, the last filled resin (28) is removed mechanically or using a laser beam as shown in FIG. 15(d).

[Problem II to be Solved by the Invention] However, in the conventional thick-walled shadow mask structure constructed by the prior art as described above, even if the resin (29) is removed after press molding, the resin (29) ) when filling two shadow mask plates (21)
, (22) It is difficult to completely remove the resin liquid that has penetrated between. As a result, impure gas gradually flows into the tube during operation of the color picture tube, shortening the life of the picture tube, and the two shadow mask plates (21) and (22) are damaged by vibrations caused by the sound of the television set's speakers. There was a problem in that the unremoved resin that remained between the tubes was scattered into the tube, and this adhered to the electron gun and caused sparks.

In addition, there was a drawback in that the electron beam passing holes (13a) and (t3b) were likely to be misaligned due to the phenomenon of residual strain returning after press molding.

This invention was made in order to solve the above-mentioned problems, and it is possible to achieve high resolution, excellent brown color purity by joining a plurality of shadow mask plates so that the electron beam passage holes are not misaligned, and Moreover, it is an object of the present invention to provide a shadow mask structure for a color picture tube that can constitute a color picture tube with a long life.

[Means for Solving the Problems] A shadow mask structure for a color picture tube according to the present invention has the following features:
The present invention is characterized in that two adjacent shadow mask plates of the plurality of shadow mask plates are welded together at a plurality of locations in the perforated wire region in which the large number of electron beam passage holes are formed.

[Function] According to the present invention, since a thick shadow mask structure is constructed by welding two shadow mask plates adjacent to each other at a plurality of locations in the perforated wire area, there are It is possible to prevent a large number of electron beam passing holes in the hole line region from being misaligned. This makes it possible to densely form thick and small electron beam passing holes, which suppresses color shift due to thermal deformation of the shadow mask structure, maintains good color purity, and improves color image reception. The resolution of the tube can be improved.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is an enlarged plan view of the main parts of a shadow mask structure for a color picture tube according to an embodiment of the present invention, viewed from the phosphor screen side;
FIG. 2 is a perspective sectional view of FIG. 1.

The overall configuration of the shadow mask type color picture tube is as follows.
Since it is similar to that shown in the figure, the following description will be made with reference to the same figure.

In Figure 1, (21) is an electron gun (12A), (1
2B).

One relatively thin shadow mask plate (12G) is disposed on the side (12G), and as clearly shown in FIGS. ) are laminated. This shadow mask plate (22) is disposed on the side of the phosphor screen (3) which is the main conductor of heat, and in order to reinforce the shadow mask plate (21), the thickness of the shadow mask plate (21) ( The plate thickness (t2) is larger than that of the plate (tl).

(30) is a slot-shaped through hole forming the electron beam passage hole (13a) provided in the shadow mask plate (21), (3Oa) is the side wall of the through hole (3o), and (31) is the shadow mask plate ( 22) through the electron beam passage hole (
This through hole (31) is a slot-shaped through hole forming a through hole (13b) on the shadow mask plate (21) side.
3G). (31a) is a side wall of the through hole (31).

(32) and (33) are the depth (t3) of the shadow mask plate (21) from the surface (22a) of the shadow mask plate (22).
), both shadow mask plates (22), (2
This is the welded part where 1) was fused and joined.

Figure 4 shows the actual values of each part when a prototype shadow mask structure (7) was made for a 29-inch color picture tube.
In the figure, (P) is the pitch of electron beam passing holes in the short axis direction of the shadow mask structure (7), which is 0.65 mm.
It is. The thickness of the shadow mask plates (22) and (21) (
tl), (t2) are 0.25mm and 0.20mm,
Further, the width of the through hole (30) of the shadow mask plate (21) on the electron gun side (Swl) is 150 JLm, which is narrower than the width (Sw2) on the side of the surface in contact with the other shadow mask plate (22). ing.

The widths of the slot-shaped through holes (31) and (30) of the shadow mask plates (22) and (21) are as follows:
For example, at a position 150 mm away from the center of the tube axis on the long axis, the shadow mask plate (21 ), (Bwl) is 1 in order to eliminate variations in the electron beam passage area due to assembly errors in the shadow mask structure.
60pm, (8w2) is 120 gm.

(Owl) is 150gm, (0w2) is 120gm, (0w3) is 250 kLm, (0w4) is 170
Produce it by setting it to pm.

Shadow mask board (22) manufactured as above
, (21) are held between a holding jig (34) and an alignment jig (27), which will be described later, and a pressure of 4 kg/am is applied to both the shadow mask plates (22),
(21) are tightly attached without any gaps. In this state,
For example, using a YAG laser at o, e~0.8 joules/pulse, pulse width 10s+sec, 0.1~0
, the beam is focused by the laser processing head (35) to a beam diameter of about 15 mm, and the shadow mask plate (22) is
(21) is irradiated and welded. At this time, the diameter (Ll) of the welded part (32) on the surface of the shadow mask plate (22) is about 0.31 layers, and the diameter (L2) of the welded part of the shadow mask plate (21) is about 0.10 mm. Its depth (t3) is 0.
It should be about 1-meal.

Also, when applied to this 29-inch color picture tube,
The perforated area (23^), the non-porous area (24 Todoroki) on the outer periphery of (23B), about 50 points at a pitch of 40, the perforated area (23^), (23B
), welding was performed at about 100 points at a pitch of about 30 to 100 mm. In this state, when press molding was performed, the electron beam passing hole (13a), (
13b), there was no displacement at all, and good results were obtained.

Next, a method for manufacturing the shadow mask structure (7) having the above configuration will be schematically explained.

Figure 5 shows two shadow mask plates (21) and (2) each manufactured to a desired thickness by a chemical etching method.
2) In the schematic plan view showing 1, the non-porous areas (24^) and (24B) on the outer periphery of the perforated areas (23A) and (23B) where the electron beam passing holes are located, respectively, have the above two sheets. Positioning holes (25A), (25B) for accurately aligning the shadow mask plates (21), (22) of
) is formed.

Two shadow mask boards (2m) made in this way
, (22), as shown in FIG. 6, the above-described positioning jig (27) via the positioning holes (25A), (25B) and the positioning pin (28) that engages therewith.
Place it on top. As a result, the two shadow mask plates (21) and (22) are superimposed and positioned so that their respective electron beam passage holes match.

Thereafter, as shown in FIG. 7, the two shadow mask plates (21) and (22) are held between the holding jig (34) and the alignment jig (27) and pressure is applied. By this, both of the above shadow mask plates (22) and (21)
Seal the parts tightly together without any gaps. In this condition.

By positioning the laser processing head (35) and irradiating the welding area with the laser, both shadow mask plates (2
1) and (22) are welded together. After welding, the shadow mask structure (7) is constructed by lifting the holding jig (34) upward to release the clamping pressure.

FIG. 8 is a perspective view of the shadow mask structure (7) constructed as described above that has been press-molded into a spherical shape, and a skirt portion (8) is integrally bent and formed around the shadow mask structure (7).

In addition, in the above embodiment, the shadow mask structure (7
) is made up of two shadow mask plates (21) and (22) stacked and welded, but the shadow mask structure (7) is made up of three or more shadow mask plates welded together. Of course, the same effect can be obtained even when

Furthermore, in the above embodiment, the case where the welding of the 52 shadow mask plates (21) and (22) was performed using a laser beam was explained, but the same effect can be obtained when welding is performed using an electron beam welding machine. Needless to say, it is played.

Furthermore, in the above embodiment, the shadow mask structure (
Although a case has been described in which a bimetal is used as the thermal expansion correction mechanism (10) in 5), the same effect can be achieved by using other known means.

[Effects of the Invention] As described above, according to the present invention, a plurality of shadow mask plates formed in a layer are welded and press-formed in the perforated areas of the plurality of shadow mask plates. In addition, it is possible to construct a thick shadow mask structure, and to prevent deformation such as wrinkles due to welding distortion and separation and misalignment between the laminated shadow mask plates in the obtained thick shadow mask structure.

Therefore, in order to improve the resolution of color picture tubes, as the setting pitch of the phosphors that emit red, green, and blue light that make up the phosphor screen becomes smaller, the electron beam passing through the shadow mask structure becomes smaller. It is possible to reduce the size of the holes.

Further, in order to suppress color shift due to thermal deformation of the shadow mask structure and maintain good color purity, a thick shadow mask structure can be easily obtained.

That is, according to the shadow mask structure for a color picture tube according to the present invention, it is possible to achieve both improvement in resolution and improvement in color purity.

In particular, according to the shadow mask structure according to the present invention,
Because the shadow mask structure is thick, thermal deformation of the shadow mask plate itself occurs due to the local impact of electron beams on the shadow mask plate, as theoretically proven in an article published in the Journal of the Society of Television Engineers. In other words, by creating local doming.

A color picture tube with good color purity can be provided.

[Brief explanation of the drawing]

1 is an enlarged plan view of a main part of a shadow mask structure for a color picture tube according to an embodiment of the present invention, FIG. 2 is a perspective sectional view of FIG. 1, and FIG. 3 is taken along the line m-■ in FIG. A cross-sectional view along
Fig. 4 is an enlarged sectional view of the main parts to explain the dimensions of each part when implemented in a 21-inch color picture tube, Fig. 5 is a schematic plan view of the joined shadow mask structure, and Fig. 6 is the shadow mask structure. A perspective view to explain the manufacturing method,
Figure 7 is an enlarged cross-sectional view of the main parts showing the state during welding, showing a method for manufacturing a shadow mask structure, Figure 1ILB is a perspective view of a press-molded shadow mask structure, and Figure 9 is a part of a shadow mask type color picture tube. A cutaway perspective view, Fig. 1θ is a characteristic diagram showing the temperature rise course with respect to the elapsed operation time of the frame and shadow mask plate in a shadow mask type color picture tube, and Fig. 11 shows doming of the shadow mask structure in a color picture tube and its correction operation. A diagram for explaining an example, FIG. 12 is a diagram for explaining an example of mislanding due to thermal expansion of the frame in the shadow mask structure and its correction operation, and FIG. 13 is a diagram for explaining a shadow in a color picture tube. FIG. 14 is a diagram for explaining an example of local doming of the mask structure. FIG. 14(a) is a front view of the screen in a color picture tube, FIG. 14(b) is a plan view of the color picture tube, and FIG. FIGS. 15(a) to 15(d) are perspective views for explaining a method of manufacturing a conventional shadow mask structure for a color picture tube, and FIGS. (2)... Panel, (3)... Fluorescent screen, (7)...
・Shadow-v Sufu body, (9)...Frame,
(13)...Electron beam passage hole, (21), (22)
...Shadow mask board, (23A). (23B) ... Perforated region, (24A), (24
B)... Non-porous area (32), (33)... Welded part. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A shadow mask body disposed facing the phosphor screen on the inner surface of the panel and in which a large number of electron beam passing holes are formed, a frame that fixes and holds the outer periphery of this shadow mask body, and Equipped with a thermal expansion correction mechanism that corrects color shift due to thermal expansion of the shadow mask body,
In the color picture tube shadow mask structure formed by welding and joining a plurality of overlapping shadow mask plates, at least two adjacent shadow mask plates of the plurality of shadow mask plates are exposed to at least the plurality of electron beams. A shadow mask structure for a color picture tube, characterized in that a perforated region in which a passage hole is formed is welded and joined at a plurality of locations.