JPH08298078A - Color picture tube - Google Patents

Abstract

PURPOSE: To provide a color picture tube which hardly causes deterioration in color purity by suppressing landing displacement caused by doming of a mas main body. CONSTITUTION: A color picture tube has a shadow mask comprising a practically square mask main body 3 in which a skirt part 39 is formed around a main face part 37 facing a fluorescent material screen through a no-hole part 38 and a practically square mask frame fixed to the skirt part 39. Slit-like through holes 43 which are long in the tube axis direction are formed in the skirt part 39 of the mask main body 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube, and more particularly to a color picture tube in which landing deviation of an electron beam with respect to a phosphor layer due to thermal expansion of a shadow mask is suppressed.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 11, a color picture tube has an outer portion composed of a substantially rectangular panel 2 having an effective portion 1 having a curved surface and a funnel-shaped funnel 3 joined to the panel 2. It has an enclosure. On the inner surface of the effective portion 1 of the panel 2, there is formed a phosphor screen 4 including a three-color phosphor layer that emits blue, green and red light. Further, a substantially rectangular shadow mask including a substantially rectangular mask body 5 inside the phosphor screen 4 and a mask frame 6 attached to the peripheral portion of the mask body 5 at a predetermined distance. 7 are arranged. The mask body 5
As shown in FIG. 12, a large number of electron beam passage holes 8 are formed in a predetermined array, a main surface portion 9 having a curved surface facing the phosphor screen, and a non-hole portion 10 surrounding the main surface portion 9 are formed. A skirt portion 11 provided around the main surface portion 9 through the non-perforated portion 10. The mask frame 6 has an L-shaped cross section and has the skirt portion 11
It is attached by welding to. On the other hand, the electron gun 15 for emitting the three electron beams 14 into the neck 13 of the funnel 3.
Is provided. Then, the three electron beams 14 emitted from the electron gun 15 are deflected by the magnetic field generated by the deflecting device 16 mounted outside the funnel 3, and the phosphor screen is passed through the electron beam passage hole 8 of the mask body 5. 4 is horizontally and vertically scanned to form a structure for displaying a color image.

Among such color picture tubes, particularly in an in-line color picture tube which emits the three electron beams 14 arranged in a row passing through the same horizontal plane, the three-color phosphor layer of the phosphor screen 4 has a tube axis. The mask body 5 is formed in a striped shape in the vertical direction (short axis direction) orthogonal to the (Z axis), and correspondingly, the mask body 5 has a plurality of vertically long electron beam passage holes 8 extending in the vertical direction. A beam passage hole array is formed, and a plurality of electron beam passage hole arrays are arranged in parallel in the horizontal direction (long axis direction, X axis direction).

By the way, the shadow mask 7 is for selecting the three electron beams 14 passing through the electron beam passage holes 8 at different angles so as to land on a predetermined phosphor layer. In order to improve the color purity of the image drawn on the phosphor screen 4 by scanning, the three electron beams 14 passing through the electron beam passage holes 8 at different angles are properly landed on the predetermined phosphor layers. It is necessary to do so. For that purpose, it is necessary that the mask main body 5 is correctly arranged in a predetermined alignment relationship with the phosphor screen 4, and the alignment relationship is maintained during the operation of the color picture tube. In particular, it is necessary that the distance (q value) between the inner surface of the effective portion 1 of the panel 2 and the main surface portion 9 of the mask body 5 be kept within a predetermined allowable range.

However, due to the operating principle of the color picture tube, the electron beam that reaches the phosphor screen 4 through each electron beam passage hole 8 of the mask body 5 is 1 of the total electron beam amount emitted from the electron gun 15. Most of the other electron beams collide with the mask body 5 and are converted into heat energy, and the mask body 5 is heated to about 80 ° C. As a result, in particular, the mask body 5 is made of a cold-rolled steel plate having a large thermal expansion coefficient (1.2 × 10 ⁻⁵ / ° C.) and a plate thickness of 0.1 to 0.3 mm, and the mask frame 6 is more mechanical than that. In the shadow mask 7 made of a cold rolled steel plate having a high strength and a thickness of about 1 mm, the main surface portion 9 of the mask body 5 bulges to the phosphor screen 4 due to thermal expansion, so-called doming occurs. As a result, when the distance between the inner surface of the effective portion 1 of the panel 2 and the main surface portion 9 of the mask body 5 exceeds the allowable value, the position change of the electron beam passage hole 8 of the mask body 5 causes 3
The landing of the electron beam 14 on the color phosphor layer is deviated, and the color purity is deteriorated.

The landing displacement of the three electron beams with respect to the three-color phosphor layer is caused by thermal expansion of the entire mask main body 5 at the beginning of the operation of the color picture tube, and a high brightness image is locally displayed. In some cases, there is a landing shift caused by local doming. The magnitude of the landing deviation varies depending on the brightness of the image pattern drawn on the screen, its duration, and the like. For example, when a high-intensity image is displayed on the entire screen for a long time, the color purity deteriorates in a relatively wide range over the entire screen. Also, when displaying a high brightness image locally,
As indicated by a broken line 18 in FIG. 13, local doming occurs, the landing shifts in a short time, and the landing shift is large, and local color purity deterioration occurs.

With respect to the landing deviation caused by the local doming, as shown in FIG. 14, a rectangular high-intensity pattern 20 having a long diameter in the vertical direction is drawn on the phosphor screen 4 by a large current beam, and its shape, As a result of changing the position and measuring the amount of landing deviation, it becomes the largest when the high-intensity pattern 20 is drawn horizontally at a position about 1/3 of the screen horizontal direction diameter (major axis) W from the screen center. As shown in FIG. 15, the result is that the elliptic region 21 in the horizontal middle portion has the largest value.

The reason why the landing deviation becomes large at the horizontal middle portion can be explained as follows. That is, the high-intensity pattern 20 shown in FIG.
Is drawn in the center of the screen, this high-intensity pattern 20
The central portion of the main surface portion of the mask body is heated corresponding to the above and thermally expands, but the electron beam passing through the electron beam passage hole in the central portion of the main surface portion has a small deflection angle, and therefore the landing deviation is small. However, the deflection angle increases as it is moved horizontally from the center of the screen, and the degree of landing shift due to thermal expansion of the mask body appears on the screen. However, since the horizontal edges of the main surface of the mask body that correspond to the horizontal edges of the screen are attached to the mask frame with high mechanical strength, thermal expansion of the mask body is suppressed, and both horizontal edges of the screen are suppressed. Landing gap of is small. As a result, the landing displacement due to the thermal expansion of the mask main body is caused by the high-intensity pattern 2 in the middle part which is horizontally separated from the center part of the screen by about ⅓ of the horizontal diameter W of the screen.
When 0 is drawn, that is, it becomes the largest in the elliptical region 21 in the horizontal middle portion shown in FIG. This elliptical area 21
Is a region centered at a position P1 which is approximately ⅓ of the horizontal diameter of the main surface portion in the horizontal direction from the center of the main surface portion of the mask body and has a width of approximately ¼ of the horizontal diameter. Correspond.

Conventionally, some means have been developed for suppressing the landing displacement due to the doming of the mask body. In particular, the following means (a) and (b) are provided to suppress the landing deviation at the beginning of the operation. (A) A graphite layer containing graphite as a main component is provided on the surface of the main surface portion of the mask main body in order to accelerate heat radiation of the mask main body by the means described in US Pat. No. 2,826,538. This graphite layer is used as a radiator to lower the temperature of the mask main body. (B) By means described in Japanese Patent Application No. 58-148843, the main surface of the mask main body on the electron gun side. A glass layer such as lead borate glass is provided on the surface. ◎ When the lead borate glass layer is provided in this way, its thermal conductivity is smaller than that of the mask body, so that the amount of heat transferred to the mask body is reduced, and the temperature rise of the mask body can be suppressed. . Further, the mechanical strength of the mask body is improved by providing the lead borate glass layer. Further, when lead borate glass is fused and crystallized on the mask body, compressive stress acts on the glass layer and tensile stress acts on the mask body, and the tensile strength of the mask body is improved.

By these means, it is possible to suppress local doming of the mask body.

Further, as means for suppressing local doming of the mask main body, there is a method of increasing the curvature of the main surface portion of the mask main body. For this method, it is known that increasing the curvature in the minor axis direction is particularly effective.

[0012]

As described above, in the shadow mask of the color picture tube, the main body of the shadow mask is heated and thermally expanded by the collision of the electron beam emitted from the electron gun, and the main surface portion is directed toward the phosphor screen. There is a problem that bulging doming occurs, the landing of the electron beam on the three-color phosphor layer shifts, and the color purity deteriorates.

Conventionally, some means have been developed for suppressing the landing displacement due to the doming of the mask body.

As one of them, as shown in (a), there is a method of providing a graphite layer on the surface of the main surface of the mask body.
However, in this method, the adhesion of the graphite layer deteriorates due to the heat treatment repeated in the manufacturing process of the color picture tube, and it is easy to peel off due to the vibration applied to the color picture tube, and the peeled minute pieces adhere to the mask body and pass through the electron beam. It clogs the holes and degrades the quality of the image displayed on the phosphor screen. In addition, problems such as adhesion to the electron gun or its vicinity to induce spark discharge and deterioration of withstand voltage characteristics are likely to occur.

As shown in (b), there is a method of providing a glass layer such as lead borate glass on the surface of the main surface of the mask body on the electron gun side. However, in this method, the amount of lead oxide (PbO) contained in the lead borate glass is 70-8.
Since it is as large as 5%, diffuse reflection in the tube of the electron beam shielded by the shadow mask is increased, and a reduction in contrast, which is usually called whitening, occurs. The plate thickness is 0.1 to 0.
When a layer of lead borate glass is provided on a mask body made of a 3 mm cold-rolled steel plate, a compressive stress acts on the glass layer and a tensile stress acts on the mask body due to its welding and crystallization.
When the balance of these stresses is lost, the mask body is easily deformed. That is, the thickness of the glass layer is usually 10 to 10.
It is said that 20 μm is preferable, but for example, the plate thickness is 0.
If a glass layer having a thickness of more than 20 μm is formed on a mask body made of a cold-rolled steel sheet of 2 mm or less due to manufacturing variations, there is a problem that the mask body is deformed.

As shown in (c), there is a method of increasing the curvature of the main surface of the mask body. Particularly in this method, it is known that increasing the curvature in the minor axis direction is effective. However, regarding this method, in a flat color picture tube with a small effective part curvature of the panel recently, the inner surface of the effective part also has a small curvature, and correspondingly, the curvature of the main surface part of the mask main body also corresponds to the center of the mask main body. It becomes small from the circumference to the periphery. Therefore, in the flattened color picture tube, the vertical end P2 of the elliptical region 21 shown in FIG. 15 tends to spread to the periphery of the long side. Further, in the flattened color picture tube, in order to increase the curvature of the main surface portion of the mask body, it is necessary to increase the curvature of the inner surface of the effective portion of the panel. Therefore, especially in a horizontally long color picture tube having an aspect ratio of 4: 3, the difference in wall thickness between the central portion and the peripheral portion of the panel becomes extremely large, which is not preferable in terms of characteristics. Further, even in the conventional ordinary color picture tube, the heat capacity is different between the main surface portion of the mask body where the electron beam passage hole is formed and the non-hole portion where the electron beam passage hole is not formed. A heat conduction difference occurs at the boundary with the part. Therefore, in the temperature distribution of the mask body, as shown by the curve 23 in FIG. 7, the temperature of the main surface portion becomes extremely higher than the temperature of the non-hole portion, and there is a problem that the doming of the main surface portion is likely to be large. is there.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide a phosphor layer by doming the mask body without providing a graphite layer or a glass layer on the main surface of the mask body. The purpose is to configure a color picture tube that suppresses the landing shift of the electron beam and is less likely to cause deterioration in color purity. The second purpose is to configure a color picture tube that suppresses the landing shift of the electron beam with respect to the phosphor layer due to the doming of the mask body without increasing the curvature of the main surface portion of the mask body and is less likely to cause deterioration in color purity. To do.

[0018]

A large number of electron beam passage holes are formed in a main surface portion facing a phosphor screen, and a skirt portion is formed around this main surface portion through a non-perforated portion. In a color picture tube having a shadow mask composed of a mask body having a shape and a substantially rectangular mask frame attached to the skirt portion, a slit-shaped through hole long in the tube axis direction is formed in the skirt portion of the mask body. did.

Further, a large number of electron beam passage holes are formed in the main surface portion facing the phosphor screen, and a skirt portion is formed around this main surface portion through a non-perforated portion to form a substantially rectangular mask body. And a shadow mask having a substantially rectangular mask frame attached to the skirt portion, and the electron beam passage holes form electron beam passage hole rows extending in a row in the short axis direction of the mask body. In a color picture tube in which a plurality of rows of the electron beam passage holes are arranged in the major axis direction of the mask body, the major axis of the major axis of the mask body is about 1/3 of the major axis of the mask body from the minor axis of the mask body. In the non-hole portion on the long side located in the width range of about ¼, a through hole long in the minor axis direction or a concave hole having a bottom plate thickness smaller than that of the mask body was formed.

Further, the minor axis is formed on the long-side non-hole portion located in the range of the width of about 1/3 of the major axis of the mask main body from the minor axis of the major axis of the mask main body. A through hole that is long in the direction or a bottom hole having a plate thickness thinner than the plate thickness of the mask body, and about 1/3 of the major axis of the mask body.
A through hole long in the tube axis direction was formed in the skirt portion on the long side located in the range of a width of about 1/4 of the major axis around the position of.

[0021]

As described above, the rigidity of the skirt portion can be reduced by forming the slit-shaped through hole that is long in the tube axis direction in the skirt portion of the mask body. Therefore, even if the mask body is heated and thermally expanded due to the collision of the electron beam, the thermal expansion is absorbed by the deformation of the skirt portion, and the masking body doming in which the main surface portion bulges toward the phosphor screen is reduced. can do. As a result, it is possible to prevent the deterioration of the color purity due to the landing shift of the electron beam with respect to the phosphor layer.

Further, about 1/3 of the major axis of the mask main body from the minor axis of the major axis of the mask main body.
In the non-hole portion on the long side located in the width range of / 4, a through hole that is long in the short axis direction or a concave hole whose bottom plate thickness is thinner than that of the mask body is formed, and more preferably, the mask body Through-holes or bottom plates that are long in the short axis direction in the non-hole portion on the long side located in the range of the width of about 1/3 of the major axis of the mask main body from the minor axis A skirt on the long side that forms a concave hole whose thickness is thinner than the plate thickness of the mask body and is located in a range of a width of about 1/4 of the major axis of the mask main body about the position of about 1/3 of the major axis. When a through hole that is long in the tube axis direction is formed in the tube portion, the main surface portion where the electron beam passage hole is formed and the non-hole portion where the electron beam passage hole is not formed have different heat capacities The temperature difference at the boundary with the non-hole portion can be reduced, and the temperature rise of the main surface can be suppressed. Doming parts can be reduced. Further, by optimizing the arrangement interval of the electron beam passage hole array and the curvature of the main surface portion, it is possible to suppress the doming of the elliptical region (see FIG. 16) in which the conventional local doming largely appears. As a result, it is possible to prevent the deterioration of the color purity due to the landing shift of the electron beam with respect to the phosphor layer.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

Example 1. FIG. 1 shows a color picture tube of the first embodiment. This color picture tube has an envelope having a substantially rectangular panel 2 whose effective portion 1 is a curved surface, and a funnel-shaped funnel 3 joined to the panel 2. The inner surface of the effective portion 1 of the panel 2 emits light of blue, green and red 3
A phosphor screen 4 including a color phosphor layer is formed. Furthermore, at a predetermined distance from the phosphor screen 4,
The mask body 30 and the mask body 3 which will be described later are provided inside thereof.
A substantially rectangular shadow mask 32 composed of a mask frame 31 attached to the periphery of 0 is arranged, and a plurality of stud pins 33 provided on the panel 2 and each stud pin 33 attached to the mask frame 31. It is supported inside the panel 2 by a plurality of elastic supports 34 that are locked to. On the other hand, the neck 13 of the funnel 3
An electron gun 15 that emits the three electron beams 14 is provided therein. Then, the three electron beams 14 emitted from the electron gun 15 are deflected by the magnetic field generated by the deflecting device 16 mounted outside the funnel 3, and the phosphor screen is passed through the electron beam passage hole 8 of the mask body 5. 4 is horizontally and vertically scanned to form a structure for displaying a color image.

Mask body 30 of the shadow mask 32
Is formed in a substantially rectangular shape made of a cold-rolled steel plate having a plate thickness of 0.1 to 0.3 mm. As shown in FIG. 2A, the mask main body 30 is formed on a curved surface facing the phosphor screen. Of a plurality of slit-shaped electron beam passage holes 36 extending in the short axis direction (Y-axis direction) form an electron beam passage hole row extending in a row in the short axis direction. Of the main surface portion 37 formed in a plurality of rows in the long axis direction (X-axis direction), a non-hole portion 38 surrounding the main surface portion 37, and a skirt provided around the main surface portion 37 via the non-hole portion 38. And part 39. The central portion and the corner portion skirt portion 39 of the long side and short side skirt portions 39
A plurality of notches 40 are provided in each of the open end portions of the. On the other hand, the mask frame 31 is formed of a cold-rolled steel plate having a plate thickness of about 1 mm and has a substantially rectangular shape with an L-shaped cross section. Then, the mask body 30 and the mask frame 31 are provided with a skirt portion 39 of the mask body 30.
On the inner side of the mask frame 31 and is welded by the tongue portion 41 surrounded by the notch 40.

Further, in the mask main body 30 of the first embodiment, the width direction of the skirt portion 39 (corresponding to the tube axis direction) is respectively in the middle portion between the central portion and the corner portion of the long side and short side skirt portions 39. ), A plurality of slit-shaped openings 43 shown in FIG. These holes 4
Of the three holes, particularly for the opening 43 on the long side, it is preferable that the major axis w of the mask body 30 be extended from the short axis of the mask body 30.
Centered on a position of about 1/3 of about 1/4 of the major axis w
Is provided within the range of the width.

Like the conventional mask body, such a mask body 30 is manufactured by forming a flat plate-shaped flat mask by a photo-etching method and then press-molding the flat mask. At the time of forming, as shown in FIG. 3, the electron beam passage holes 36 are formed in a predetermined array on the portion 37a which becomes the main surface portion facing the phosphor screen, and at the same time, the portion which becomes the skirt portion when forming Notch 4 on 39a
It is obtained by forming 0 and the opening 43.

By the way, as described above, the mask body 30
When the slit-shaped opening 43 is provided in the skirt portion 39, the rigidity of the skirt portion 39 can be made lower than that of the conventional mask body in which the slit-shaped opening is not provided in the skirt portion. As a result, as shown in FIG. 4A, when the mask body 30 is heated and thermally expanded due to the collision of the electron beam, the thermal expansion is absorbed by the deformation of the skirt portion 39 shown by the broken line, and the main surface portion 37. It is possible to reduce the doming that bulges in the phosphor screen direction.

That is, in the conventional shadow mask, as shown in FIG. 4B, the peripheral portion of the mask body 5 is attached to the mask frame 6 through the skirt portion 11 having a relatively high rigidity. When the mask body 5 is heated by the collision of the electron beam, thermal expansion causes the main surface portion 9 to bulge largely in the phosphor screen direction as shown by the broken line, and the electron beam is applied to the phosphor layer. Although the landing was deviated and the color purity was deteriorated, when the slit-shaped opening 43 was provided in the skirt portion 39 as in the mask body 30 of this example, the rigidity was lowered, as shown in FIG. The skirt portion 39 is deformed, and the doming in which the main surface portion 37 bulges toward the phosphor screen 4 can be reduced. Therefore, the landing deviation of the electron beam with respect to the phosphor layer is reduced,
It is possible to prevent deterioration of color purity. Moreover, even if the skirt portion 39 of the mask body 30 is provided with the slit-shaped openings 43 as described above, the open end of the skirt portion 39 is connected in the same manner as the skirt portion of the conventional mask body, and thus the inside of the mask frame. The skirt can be assembled in the same manner as a conventional shadow mask without making it difficult to insert the skirt into the shadow mask.

In the above-mentioned embodiment, the slit-shaped opening in the skirt portion of the mask body was formed at the same time as the electron beam passage hole in the main surface portion by the photo-etching method when the flat mask was formed. ), When a flat mask is formed by a photo-etching method, a slit-like opening in the skirt portion is not formed at the same time as the electron beam passage hole 36 in the main surface portion, and after the flat mask is formed,
By punching, as shown in (b), a slit-shaped opening 43 is formed in the skirt portion of the flat mask.
May be formed.

Embodiment 2 FIG. The overall structure of the color picture tube is
Since it is almost the same as the color picture tube of the first embodiment, the description thereof will be omitted, and the mask main body, which is the main configuration thereof, will be described.

The mask main body of the second embodiment has a plate thickness of 0.1.
As shown in FIG. 6A, a plurality of slit-shaped electron beam passage holes 3 are formed on the curved surface facing the phosphor screen, and are formed in a substantially rectangular shape made of a cold-rolled steel plate of 0.3 mm.
6 constitutes an electron beam passage hole array extending in a row in the short axis direction of the mask body 30, and a plurality of electron beam passage hole arrays are formed in the major axis direction of the mask body 30;
The non-hole portion 38 surrounding the main surface portion 37, and the non-hole portion 38
Skirt portion 3 provided around the main surface portion 37 via
9 and 9.

Furthermore, in the mask body of the second embodiment, the mask body is positioned within a range of about 1/3 of the major axis w of the mask body from the minor axis of the mask body to about 1/4 of the major axis w. The non-hole portion 38 on the long side is longer in the short axis direction of the mask main body and has a plate thickness of the non-hole portion 38 as shown in FIG. 6B.
A slit-shaped concave hole 45 thinner than the plate thickness of the other portion, that is, the plate thickness of the mask body 30 is formed. Further, as shown in (c), the skirt portion 39 on the long side located in the range of the width of about 1/4 of the major axis w around the position of about 1/3 of the major axis w of the mask body. A slit-shaped opening 43 that is long in the tube axis direction is formed. 40
Are notches formed in the open end edges of the long side and short side skirts 39 and the corner skirt 39.

Such a mask body is manufactured by forming a flat flat mask by a photo-etching method and then press-molding the flat mask. When the flat mask is formed, etching is performed from both sides. Then, an electron beam passage hole is formed in a portion which becomes a main surface portion facing the phosphor screen, and an opening 43 is formed in the skirt portion 39, and at the same time, the non-hole portion 38 is etched from one surface to form a concave hole 45. It is obtained by forming.

As described above, when the long hole side non-hole portion 38 of the mask main body is provided with the long concave hole 45 in the short axis direction of the mask main body, even if the mask main body is heated by the collision of the electron beam, the mask main body shown in FIG. As indicated by a curve 47 with the short axis of the mask body as the horizontal axis and the temperature as the vertical axis, the temperature distribution of the entire mask body can be made uniform. That is, as described above, in the conventional mask body in which no concave hole is formed in the non-hole portion, since the main surface portion where the electron beam passage hole is formed and the non-hole portion have different heat capacities, heat conduction occurs at the boundary portion. A difference occurs, curve 2
As shown in 3, the temperature of the main surface portion became extremely higher than the temperature of the non-porous portion, which caused a large amount of doming of the main surface portion. However, when the concave hole is formed in the non-porous portion as described above. ,
The difference in heat conduction is reduced at the boundary between the main surface and the non-perforated part, and the temperature of the main surface is lower and the temperature of the non-perforated part is higher than that of the conventional mask body, and the temperature distribution of the entire mask main body is uniform. Turn into. The uniformization of the temperature distribution of the entire mask body is further promoted by forming the slit-shaped opening long in the skirt portion in the same direction as the tube axis as described above. Moreover, the opening of the skirt portion lowers the rigidity of the skirt portion similarly to the mask body of the first embodiment, thereby absorbing the thermal expansion of the mask body, and the main surface portion bulges toward the phosphor screen. To reduce. As a result, the temperature distribution is made uniform and the rigidity of the skirt portion is reduced, so that the deterioration of color purity caused by the conventional doming of the mask main body can be eliminated.

Further, the concave hole 45 of the non-perforated portion 38 and the opening 43 of the skirt portion 39 are centered at a position about 1/3 of the major axis w of the mask body from the minor axis of the mask body, and the major axis w is about 1 of the major axis w.
/ 4 width, slit-shaped opening 4 long in the tube axis direction
By forming No. 3, it is possible to reduce the local doming of the part that is most likely to occur when a high-intensity image is locally displayed in the related art, and the electron beam to the phosphor layer in the elliptic region 21 shown in FIG. Landing deviation can be effectively reduced. Such an effect is particularly effective in the case of a flattened color picture tube in which the curvature of the effective portion of the panel is small like the recent color picture tubes because it is difficult to increase the curvature of the mask body.

Further, the mask main body of the second embodiment is shown in FIG.
As shown in (4), by optimizing the spacing between the electron beam passage hole arrays, the curvature of the main surface portion can be appropriately changed without a landing error. Therefore, the curvature on the major axis can be increased, and the doming of the entire mask body can be suppressed. That is, as shown in FIG. 8, the curvature in the short axis direction indicated by the curve 48 at the peripheral portion of the mask body 30 in the long axis direction is represented by the curve 4.
9, the radius of curvature Ry can be made large, and the curvature in the minor axis direction can be made small, so that the curvature on the major axis perpendicular to the plane of the sheet passing through the point 50 can be made large, and the entire mask body 30 Doming can be suppressed. However, in this case, the arrangement pitch of the stripe-shaped three-color phosphor layers B, G, and R of the phosphor screen is set to PH in FIGS. 9B and 9C.
As shown by the distance between P and the three-color phosphor layers B, G, and R as d, d <(2/3) PHP or d> (2/3) PHP, resulting in deterioration of phosphor screen quality. . Therefore, in order to change the curvature of the mask body, it is necessary to appropriately adjust the interval of the electron beam passage hole array to make it appropriate, and as shown in FIG. 9A, d = With (2/3) PHP, a color picture tube without deterioration of the phosphor screen quality can be constructed. In the above embodiment, the concave hole was formed only in the non-hole portion on the long side of the mask body, but this concave hole is formed in addition to the non-hole portion on the long side, the non-hole portion on the short side and the skirt. When the mask body is formed in the same area, the doming of the mask body is not so different from that of the above-mentioned embodiment, but when the high-intensity image is continuously displayed for a long time, the heat capacity of the mask body becomes small due to the formation of the opening. This increases the domin of the mask body, which is not preferable.

Example 3. The overall structure of the color picture tube is
Since it is almost the same as the color picture tube of Embodiment 1, the description thereof will be omitted, and the mask main body of the shadow mask, which is the main configuration thereof, will be described.

The mask main body of the third embodiment has a long slit-shaped opening in the minor axis direction of the mask main body instead of the concave hole of the non-hole portion of the mask main body of the second embodiment.
Slits are formed in the non-hole portion and the skirt portion on the long side located in the range of the width of about 1/4 of the major axis of the mask body from the short axis of the mask body about 1/3 of the major axis of the mask body. -Shaped openings are formed.

When a flat mask having a flat plate shape is formed by a photo-etching method, such a mask body is etched from both sides to form an electron beam passage hole at a portion serving as a main surface portion facing the phosphor screen. The holes 53 are also formed in the non-hole portion and the skirt portion, and then press-molded.

When the mask main body is constructed in this way, the difference in heat capacity between the main surface portion and the non-hole portion is small because an opening is formed instead of the concave hole of the non-hole portion of the mask main body of the second embodiment. Therefore, a larger effect than that of the second embodiment can be obtained.

For the color picture tube in which this mask body was actually incorporated, the landing shift of the electron beam with respect to the three-color phosphor layer due to local doming was measured. As a result, on the long axis of the phosphor screen shown in FIG. Point P1
The improvement in landing deviation was about 3%, but the landing deviation was improved by about 10% at the peripheral point P2 passing through the point P1 in the elliptical region. Also in this mask body, like the mask body of the second embodiment,
By correcting the radius of curvature Ry in the minor axis direction shown in FIG. 8 and optimizing the array pitch PHP of the stripe-shaped three-color phosphor layers of the phosphor screen as shown in FIG. Can further suppress the doming on the long axis.

Since the mask main body of the third embodiment has the holes formed in the non-hole portion, when the phosphor screen is formed on the inner surface of the panel by the photo printing method, the non-hole portion 38 is opened. Since the hole pattern is also baked, it is necessary to form the light absorption layer on the outer peripheral portion of the phosphor screen forming region before forming the three-color phosphor layer on the inner surface of the effective portion of the panel.

Example 4. The overall structure of the color picture tube is
Since it is almost the same as the color picture tube of Embodiment 1, the description thereof will be omitted, and the mask main body of the shadow mask, which is the main configuration thereof, will be described.

As shown in FIG. 10, the mask main body of the fourth embodiment has about 1/3 of the major axis w of the mask main body centered on a position about 1/3 of the major axis w of the mask main body from the minor axis of the mask main body.
In the non-hole portion 38 on the long side located in the width range of / 4, a long slit-shaped opening 52 is formed in the same direction as the short axis of the mask body, but on the skirt portion 39 on the long side. Has no open hole.

When a flat plate-shaped flat mask is formed by the photo-etching method, such a mask body is also etched from both sides to form an electron beam passage hole at a portion which becomes a main surface portion facing the phosphor screen. The hole 53 is formed in the non-hole portion 38, and then press-molded.

Even if the mask body is constructed as described above, substantially the same effect as that of the mask body of the third embodiment can be obtained.

[0048]

EFFECTS OF THE INVENTION A large number of electron beam passage holes are formed in a main surface portion facing a phosphor screen, and a skirt portion is formed around this main surface portion through a non-perforated portion to form a substantially rectangular mask body. In a color picture tube having a shadow mask consisting of a mask frame having a substantially rectangular shape attached to the skirt portion, if a slit-shaped through hole long in the tube axis direction is formed in the skirt portion of the mask body, the skirt portion The rigidity of can be lowered. Therefore, even if the mask body is heated and thermally expanded due to the collision of the electron beam, the thermal expansion is absorbed by the deformation of the skirt portion, and the masking body doming in which the main surface portion bulges toward the phosphor screen is reduced. can do. As a result, it is possible to prevent the deterioration of the color purity due to the landing shift of the electron beam with respect to the phosphor layer.

Further, about 1/3 of the major axis of the mask body is centered at a position about 1/3 of the major axis of the mask body.
In the non-hole portion on the long side located in the width range of / 4, a through hole that is long in the short axis direction or a concave hole whose bottom plate thickness is thinner than that of the mask body is formed, and more preferably, the mask body Through-holes or bottom plates that are long in the short axis direction in the non-hole portion on the long side located in the range of the width of about 1/3 of the major axis of the mask main body from the minor axis A skirt on the long side that forms a concave hole whose thickness is thinner than the plate thickness of the mask body and is located in a range of a width of about 1/4 of the major axis of the mask main body about the position of about 1/3 of the major axis. When a through hole that is long in the tube axis direction is formed in the tube portion, the main surface portion where the electron beam passage hole is formed and the non-hole portion where the electron beam passage hole is not formed have different heat capacities The temperature difference at the boundary with the non-hole portion can be reduced, and the temperature rise of the main surface can be suppressed. Doming parts can be reduced. Further, by optimizing the arrangement interval of the electron beam passage hole array and the curvature of the main surface portion, it is possible to suppress the doming of the elliptical region (see FIG. 16) in which the conventional local doming largely appears. As a result, it is possible to prevent the deterioration of the color purity due to the landing shift of the electron beam with respect to the phosphor layer.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a color picture tube according to a first embodiment of the present invention.

FIG. 2 (a) is a diagram showing a configuration of a mask body of the shadow mask, and FIG. 2 (b) is a diagram showing openings of a skirt portion of the mask body.

FIG. 3 is a view of a flat-plate flat mask shown for explaining the method for manufacturing the mask body.

FIG. 4 (a) is a diagram for explaining the action on the thermal expansion of the mask body, and FIG. 4 (b) is a diagram for explaining the action on the thermal expansion of the conventional mask body shown for comparison. FIG.

5A and 5B are views of a flat mask shown for explaining another method of manufacturing the mask body.

FIG. 6 (a) is a diagram showing a configuration of a mask main body of a color picture tube of Embodiment 2 of the present invention, FIG. 6 (b) is a diagram showing a concave hole of its non-hole portion, and FIG. [Fig. 4] is a view showing an opening of a skirt portion.

FIG. 7 is a diagram showing the temperature distribution of the mask body of Example 2 in comparison with the temperature distribution of the conventional mask body.

FIG. 8 is a diagram for explaining the curved surface shape of the main surface portion of the mask main body of the second embodiment.

9 (a) to 9 (c) are views for explaining a curved surface shape of the main surface portion of the mask main body and an arrangement state of stripe-shaped three-color phosphor layers of the phosphor screen, respectively.

FIG. 10 (a) is a diagram showing a configuration of a mask main body of a color picture tube of Embodiment 4 of the present invention, and FIG. 10 (b) is a diagram showing an opening of a non-hole portion thereof.

FIG. 11 is a diagram showing a configuration of a conventional color picture tube.

FIG. 12 is a diagram showing a configuration of a mask main body of the conventional color picture tube.

FIG. 13 is a diagram for explaining a landing shift of an electron beam with respect to a phosphor layer due to local doming of a mask body of the conventional color picture tube.

FIG. 14 is a diagram for explaining a situation of occurrence of local doming of the mask body.

FIG. 15 is a diagram showing a region where landing displacement occurs due to local doming of the mask body.

[Explanation of symbols]

 4 ... Phosphor screen 30 ... Mask body 31 ... Mask frame 36 ... Electron beam passage hole 37 ... Main surface portion 38 ... Non-hole portion 39 ... Skirt portion 43 ... Opening hole 45 ... Recessed hole 52 ... Opening hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Shimizu 1-9-2 Harara-cho, Fukaya-shi, Saitama Prefecture Fukaya Electronics Factory, Toshiba Corp. (72) Shinichiro Nakagawa 1-9, Harara-cho, Fukaya-shi, Saitama No. 2 inside Toshiba Fukaya Electronics Factory

Claims (3)

[Claims] 1. A substantially rectangular mask body in which a large number of electron beam passage holes are formed in a main surface portion facing a phosphor screen, and a skirt portion is formed around this main surface portion through a non-hole portion. And a color picture tube having a shadow mask consisting of a substantially rectangular mask frame attached to the skirt portion, wherein the mask body has a slit-shaped through hole formed in the skirt portion in the tube axial direction. A color picture tube characterized by being installed. 2. A substantially rectangular mask body in which a large number of electron beam passage holes are formed in a main surface portion facing a phosphor screen, and a skirt portion is formed around this main surface portion through a non-hole portion. And a shadow mask consisting of a substantially rectangular mask frame attached to the skirt portion, wherein the electron beam passage holes have electron beam passage hole rows extending in a row in the minor axis direction of the mask body. In the color picture tube in which the electron beam passage hole array is arranged in a plurality of rows in the major axis direction of the mask body, the mask body is arranged from the minor axis of the mask body to about 1/3 of the major axis of the mask body. At the long-side non-hole located in the width range of about 1/4 of the major axis with the through hole being long in the minor axis direction or the bottom plate thickness being thinner than the mask body plate thickness. Is formed Color picture tube, wherein the door. 3. A substantially rectangular mask body in which a large number of electron beam passage holes are formed in a main surface portion facing a phosphor screen, and a skirt portion is formed around the main surface portion with a non-perforated portion. And a shadow mask consisting of a substantially rectangular mask frame attached to the skirt portion, wherein the electron beam passage holes have electron beam passage hole rows extending in a row in the minor axis direction of the mask body. In the color picture tube in which the electron beam passage hole array is arranged in a plurality of rows in the major axis direction of the mask body, the mask body is arranged from the minor axis of the mask body to about 1/3 of the major axis of the mask body. At the long-side non-hole located in the width range of about 1/4 of the major axis with the through hole being long in the minor axis direction or the bottom plate thickness being thinner than the mask body plate thickness. Is formed, and A long through-hole in the tube axis direction is formed in the skirt portion on the long side located in the range of about 1/4 of the major axis of the mask main body at a position of about 1/3 of the major axis. Characteristic color picture tube.