JP3184579B2 - Shadow mask, master for baking shadow mask, and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask for a color picture tube, and more particularly to a shadow mask having a substantially rectangular opening having excellent brightness and white uniformity, and a shadow mask used for manufacturing the shadow mask. The present invention relates to a printing master and a method of manufacturing the printing master .

[0002]

2. Description of the Related Art Generally, a color picture tube has an envelope comprising a spherical panel 1 and a funnel-shaped funnel 2 integrally joined to the panel 1, as shown in FIG. A phosphor screen 3 composed of a three-color phosphor layer is formed on the inner surface of the substrate 1 and a shadow mask having a large number of openings arranged in a predetermined pattern facing the phosphor screen 3 inside the phosphor screen 3. 4 is located. Then, the three electron beams 7 emitted from the electron gun 6 arranged in the neck part 5 of the funnel 2 are deflected by the magnetic field generated by the deflection yoke 8 mounted outside the funnel 2, and the three electron beams 7 are deflected. Shadow mask 4
The phosphor screen 3 is selected so that the phosphor screen 3 can be properly landed at a desired position of the three-color phosphor layer.
The structure is such that a color image is displayed on the phosphor screen 3 by vertical scanning.

[0003] As the opening shape of the shadow mask 4 as described above, there are conventionally known ones having a circular opening and those having a rectangular opening. Shadow masks having circular openings (circular hole shadow masks) are mainly used for display tubes, while shadow masks having rectangular openings (rectangular hole shadow masks) are mainly used for consumer televisions such as home televisions. It is used for

Conventionally, the opening of the rectangular hole shadow mask is as follows.
As shown in FIG. 18, it is formed in a substantially rectangular shape with rounded corners. And this opening 10 is formed such that its longitudinal axis coincides with the vertical axis direction passing through the center of the shadow mask, and particularly in the vertical axis direction, a plurality of the apertures 10 are arranged via a narrow bridge portion 11. A vertical column including a plurality of apertures in the vertical axis direction is arranged in a pattern in which a plurality of rows are arranged in parallel at a predetermined pitch in the horizontal axis direction.

[0005] In such a shadow mask, the three-color phosphor layer of the phosphor screen facing the shadow mask is constituted by a stripe-shaped three-color phosphor layer extending in the vertical axis direction.

Conventionally, a shadow mask having openings arranged in the above-described pattern has been manufactured by a photoetching method. That is, a photosensitive agent film is formed by applying a photosensitive agent on both sides of a mask material plate, and a pair of masters for baking a shadow mask in which a pattern corresponding to an opening to be formed is formed on the photosensitive agent film on both sides. Are exposed to each other and developed to form a resist pattern corresponding to the pattern of the pair of original masks for shadow mask printing. Thereafter, the mask material plate on which the resist pattern is formed is manufactured by etching from both sides.

The aperture of the shadow mask manufactured by this method can be used to form a shadow mask manufactured by printing a pattern on a photosensitive agent coating, even if the pattern of a pair of masters for printing a shadow mask is an accurate rectangle having no rounded corners. As shown in FIG. 18, a substantially rectangular large hole 13 with rounded corners at four corners is formed on one surface of the mask material plate due to dripping after baking development and a difference in etching rate. A substantially rectangular small hole 14 having rounded corners at four corners is formed on the other surface in communication with the large hole 13, and is formed inside a boundary portion where the large hole 13 and the small hole 14 communicate. An overhang 15 is formed. The size of the opening 10 is defined by the overhang portion 15, and has a substantially rectangular shape with rounded corners.

Normally, the shadow mask 4 is disposed inside the panel with the small holes 14 facing the electron gun and the large holes 13 facing the phosphor screen. Therefore, as shown in FIG. 19, the electron beam 7 landing on the three-color phosphor layer at the center of the phosphor screen passes through the opening 10 at the center of the shadow mask almost vertically as shown by a broken line, and Reach the body screen. However, the electron beam 7 landing on the three-color phosphor layer at the periphery of the phosphor screen is largely deflected, and crosses the opening 10 obliquely and reaches the phosphor screen as shown by the solid line. Thus the electron beam 7
Crosses the opening 10 at an angle, a part of the opening 10 becomes the opening edge of the large hole 13 (the opening edge on the phosphor screen side) or the opening 10.
Collides with the inner wall of the
The light-emitting area on the three-color phosphor layer formed in accordance with the shape of (3) is not rectangular, but can be chipped, and the luminance and white uniformity deteriorate. Further, there is a problem that the electron beam colliding with the inner wall of the aperture 10 and reflected causes the other color phosphor layer to emit light, thereby deteriorating color purity and contrast.

In particular, a projecting portion 15 is provided at the boundary between the large hole 13 and the small hole 14.
In the opening 10 having a shape with round holes, the roundness of the four corners changes due to dripping of the resist after baking development and a difference in etching rate, and the short side 16 and the long side 17
18 (see FIG. 18), the position of the overhang 15 in the thickness direction of the shadow mask is different. Usually, the position of the overhang 15 is such that the overhang of the short side is closer to the phosphor screen (the opening edge of the large hole 13) than the overhang of the long side, and the line 18 in the developed view shown in FIG. As shown in the above, generally, a stepped portion due to these overhangs is formed near the four corners, which is the boundary between the short side and the long side. That is, at the four corners of the opening 10, overhangs are formed which are located closer to the phosphor screen than overhangs at the long sides. Accordingly, when the electron beam obliquely crosses the opening 10 having such an overhang, as shown in FIG. 21 together with the opening 10, the electron beam is applied to the periphery of the shadow mask in the four corners of the opening 10. The light emitting region 20 on the three-color phosphor layer has a large notch 21 at the outer corner close to the three-color phosphor layer, thereby greatly deteriorating the luminance and the white uniformity.

[0010] Such a problem tends to occur particularly in the case of a flat square tube in which the radius of curvature of the panel is increased and the panel approaches a flat surface. That is, in general, the radius of curvature of the shadow mask increases correspondingly as the radius of curvature of the panel increases. When the radius of curvature increases,
Since the mechanical strength of the shadow mask decreases, it is necessary to increase the thickness of the shadow mask in order to prevent the mechanical strength from decreasing. Therefore, in such a flat square tube shadow mask, even if the electron beam is deflected at the same deflection angle as that of a normal color picture tube, the electron beam crosses the aperture of the shadow mask more obliquely. Therefore, the electron beam of the phosphor screen side of the aperture opening
It is easy to collide with the edge of the hole or the inner wall of the hole, and the deterioration of brightness, white uniformity, etc. is more marked
I do.

In order to prevent the chipping 21 of the light emitting region 20 due to the collision of the electron beam 7 obliquely crossing the opening 10, a large hole 13 and a small hole 13 are conventionally formed at the center of the shadow mask as shown in FIG. Open hole 10 with large hole by aligning the center axis of hole 14
As shown in FIG. 23, the large hole 13 is shifted outward with respect to the small hole 14 as it approaches the peripheral portion in the horizontal axis direction. As approaching, as shown in FIG.
An off-center shadow mask in which 13 is shifted outward in the diagonal axis direction is known.

However, as described above, the large hole 13 with respect to the small hole 14
When the amount of deviation is large, the shape of the opening is distorted. In particular, flat square tubes, which have a flattened radius of curvature larger than that of a normal color picture tube panel, have a larger radius of curvature of the shadow mask corresponding to the panel, and as the color picture tube becomes larger, Since the target strength is greatly reduced, a thick shadow mask is used. As a result, in such a shadow mask, as shown in FIG.
As shown by the plate thickness t2 with respect to the normal shadow mask, the electron beam 7 obliquely crosses the opening which does not collide with the normal shadow mask. Further, the width of the aperture viewed from the direction of the path of the electron beam 7 crossing obliquely becomes narrow, and the light emitting area on the phosphor layer becomes small, resulting in a decrease in luminance. In order to eliminate such an undesired collision of the electron beam 7 and a decrease in brightness, it is sufficient to increase the shift ΔW of the large hole 13 with respect to the opening 10. There is a problem that the height position of the protrusion 15 is too different between the left and right sides of the opening 10, and the shape of the opening 10 is further distorted.

As means for solving the problem of the shadow mask having a substantially rectangular opening, Japanese Patent Publication No. 63-4933 is known.
No. 6, as shown in FIG. 26, in order to reduce the roundness of the four corners of the opening 10, the four corners of the large hole 13 and the small hole 14 are projected outward to form a pin-shaped shadow mask. It is shown. Particularly, in the embodiment described in the publication, the dimensional difference between the large hole 13 and the small hole 14 in the width direction of the opening 10 and the dimensional difference between the large hole 13 and the small hole 14 in the length direction of the opening 10 are described. Are shown equal.

However, in such a shadow mask, in order to prevent the electron beam 7 from being blocked by the large hole 13 in the width direction of the opening 10, the opening edge of the large hole 13 (the opening edge on the phosphor screen side). In this case, the width wH of the bridge 15 must be increased, and as a result, the substantial width wB of the bridge 11 at the overhang 15 increases, leading to a reduction in luminance. Conversely, in order to reduce the substantial width dimension wB of the bridge portion 11, the width dimension wH of the bridge portion 11 at the opening edge of the large hole 13 must be reduced. The shielding of the electron beam 7 at the edge portion or the overhang portion 15 becomes large, which leads to deterioration of luminance and white uniformity. In such a shadow mask, FIG.
As shown in FIG. 7, a large hole 13 and a small hole in the width direction of the opening 10 are provided.
The large hole 13 and the small hole in the length direction of the opening 10 are different from the size of the hole 14.
When a structure similar to a general shadow mask larger than the dimensional difference from 14 is used, as described above, at the four corners that are the boundary between the short side 16 and the long side 17, the overhang of the short side 16 is provided. 15 and the long side
An extremely large step formed by the overhang 15 of the 17 is formed (see FIG. 15). In this case, even if the shape of the opening 10 is rectangular when viewed from directly above, the electron beam 7 obliquely crossing the opening 10 is one of the corners of the opening 10 outside the shadow mask outer peripheral direction. And the light emitting area on the three-color phosphor layer is chipped, resulting in deterioration of luminance and white uniformity.

In Japanese Patent Application Laid-Open No. 1-175148, as shown in FIG. 28, the corner of the large hole 13 is bulged outward to prevent the electron beam from being blocked at the corner of the opening 10. A shadow mask is shown. However, such a shadow mask is disclosed in JP-B-63-49336.
26 is basically the same as the shadow mask shown in FIG. 26 except that the shape of the large hole 13 is different from that of the shadow mask of the publication, and the same problem occurs. In addition, 50-122
No. 553 discloses that the central portion of the short side of the opening is bulged inward to eliminate the roundness of the end of the electron beam due to diffusion (the chipping of the corner of the light emitting region on the phosphor layer), A shadow mask having a rectangular shape is shown. However, in the case of such a shadow mask, when the bridge portion having a predetermined width is left at each opening edge of the large hole and the small hole to form a predetermined opening, the width of the bridge portion is extremely large. And lowers the brightness. Conversely, if an attempt is made to prevent such a decrease in luminance, the width of the bridge portion becomes extremely thin, and the mechanical strength in the vertical column direction comprising a plurality of apertures arranged via the bridge portion decreases. Therefore, when the shadow mask is press-formed into a predetermined shape, local elongation or deformation occurs,
A desired shadow mask cannot be obtained.

Further, as shown in FIG. 29, in Japanese Patent Application Laid-Open No. 1-320736, the large hole 13 is made substantially rectangular, and the outer corner of the small hole near the outer periphery of the shadow mask is expanded outward. And bulging the outer corners of the opening 10 outward, thereby forming a large hole of the electron beam obliquely crossing the opening 10.
13 shows a shadow mask which is designed to prevent collision at the edge of the opening of 13 or on the inner wall of the opening to prevent chipping of the light emitting area on the three-color phosphor layer. Further, as a pattern of an original mask for baking a shadow mask for forming such openings 10, Japanese Patent Application Laid-Open No. 2-86027 discloses a pattern corresponding to a small hole by multiple exposure as shown in FIG. A pattern composed of a pattern 23 and a rectangular auxiliary pattern 24 is shown.

Such a shadow mask can considerably reduce the deterioration of the white uniformity due to the lack of the light-emitting area, but cannot reduce the roundness of the corners of the opening 10 and, as a result, sufficiently increase the luminance. Can't improve. Further, at the peripheral portion of the phosphor screen having a small electron beam landing margin, the electron beam passing through the bulging portion of the opening 10 lands on the phosphor layer of another color, so that the color purity is easily reduced.

Furthermore, Japanese Patent Application Laid-Open No. 2-40840 discloses that, as shown in FIG. 31, the four corners of the small hole 14 are bulged outward and the inner wall of the short side portion 26 of the small hole 14 is inclined. By doing so, a shadow mask is shown in which the roundness of the four corners of the opening 10 is reduced. However, in such a shadow mask, the short side portion 27 of the opening 10 has an arc shape, and the linearity portion is lost. As a result, the aperture area decreases and sufficient luminance cannot be obtained. Further, since the large hole 13 is the same as a normal substantially rectangular opening, there is a problem that it is difficult for the four corners of the opening 10 to bulge outward.

Japanese Patent Application Laid-Open No. 55-159545 discloses that, as shown in FIG. 32A, the four corners of the opening 10 bulge outward, as shown in FIG. An I-shaped pattern of the master for shadow mask printing is shown. The opening 10 of the shadow mask formed by using such an original plate has an outer corner bulging outward, so that the deterioration of the white uniformity due to the collision of the electron beam obliquely across the opening 10 is described. Can be improved to some extent. However, since the large hole is substantially rectangular, the corners of the small hole are bulged outward to form the opening 10, so that the roundness of the four corners of the opening 10 cannot be reduced, and the reduction in luminance is sufficiently reduced. Can not be improved.

Further, in order to reduce the roundness of the four corners of the opening, Japanese Patent Application Laid-Open No. 56-156636 discloses a pattern 28 of an original mask for printing a shadow mask as shown in FIG.
Was in a shape having a protruding portion 29 that protrudes in tens of microns acute
Is shown thing was. Such apertures of the shadow mask formed by using the precursor can be a roundness of the four corners is small rectangular shape. However, no bulge is formed at the outer corner where an electron beam obliquely crossing the opening is likely to collide. Therefore, in this opening, it is not possible to prevent the light emitting region from being chipped, and the white uniformity is deteriorated.

[0021]

As described above, a substantially rectangular opening is formed, and the longitudinal axis of the rectangular opening is formed so as to coincide with the direction of a vertical axis passing through the center of the shadow mask. In particular, in the vertical axis direction, a plurality of rectangular openings are arranged through a narrow bridge portion, and a plurality of vertical columns formed of a plurality of openings in the vertical axis direction are arranged in parallel at a predetermined pitch in the horizontal axis direction. In a shadow mask having holes, an electron beam landing on the three-color phosphor layer through the opening obliquely crosses the opening with an increase in deflection. The light does not reach the phosphor screen by colliding with the opening edge on the screen side or the inner wall of the opening, resulting in chipping of the light emitting area, deteriorating luminance and white uniformity. There is also a problem that the electron beam colliding with the inner wall of the aperture and reflected causes the other color phosphor layer to emit light, thereby deteriorating color purity and contrast.

In order to solve such a problem, Japanese Patent Publication No. Sho 6
JP-A-3-49336, JP-A-1-175148, JP-A-50-122553, JP-A-1-32
JP-A-0738 and JP-A-2-40840 disclose shadow masks in which the corners of a rectangular opening are bulged outward. JP-A-2-86027, JP-A-55-159545, and JP-A-56-1
No. 56636 discloses a master for baking a shadow mask for producing a rectangular opening whose corners bulge outward.

However, the shadow mask in which the corners of the rectangular opening are bulged outward and the shadow mask manufactured by using the original mask for baking the mask have a certain degree of luminance, white uniformity, and the like. There is a problem that it can be improved but cannot be sufficiently improved.

The present invention has been made in view of the above-mentioned problems, and since the electron beam obliquely crosses a substantially rectangular opening of the shadow mask with an increase in deflection,
A part of the electron beam collides with the opening edge of the aperture on the phosphor screen side or the inner wall of the aperture, and a shadow mask or shadow mask that prevents deterioration of brightness and white uniformity caused by not reaching the phosphor screen. An object of the present invention is to obtain a printing master and a method of manufacturing the shadow mask printing master.

[0025]

Means for Solving the Problems: It is formed in a substantially rectangular shape,
In a shadow mask having a vertical axis passing through the center and a horizontal axis passing through the center, and having a large number of substantially rectangular openings arranged in a predetermined pattern, each of the openings defines a longitudinal axis substantially parallel to the vertical axis. These openings are arranged so that a plurality of vertical rows formed by arranging a plurality of openings parallel to the vertical axis are formed in a plurality at a predetermined pitch in the horizontal axis direction, and adjacent openings in each vertical row are formed. Are vertically separated by a bridge portion, a pair of outer corners in which openings other than the opening on the vertical axis are separated from the vertical axis, a pair of inner corners located on the vertical axis side, and the outer corners And a pair of swelling portions swelling outward in the horizontal axis direction, respectively, and the swelling portion is formed so that the swelling amount gradually increases as the opening is further away from the vertical axis.

In the above-mentioned shadow mask, each opening has both end edges defined by a bridge portion, and both end edges extend in the horizontal axis direction, and both end edges extend in the horizontal axis direction at the center of the opening. It was a straight line longer than the width.

Further, in a shadow mask which is formed in a substantially rectangular shape, has a vertical axis passing through the center and a horizontal axis passing through the center, and has a large number of substantially rectangular openings arranged in a predetermined pattern. Each has a longitudinal axis substantially parallel to the vertical axis, and these apertures are formed by arranging a plurality of vertical rows formed by arranging a plurality of apertures parallel to the vertical axis at a predetermined pitch in the horizontal axis direction. Arrange, adjacent holes in each vertical row are separated in the vertical axis direction by a bridge portion, and each hole on the vertical axis has a bulging portion bulging outward from the four corners in the horizontal axis direction. A pair of outer corners formed vertically and horizontally symmetrically, with openings other than the opening on the vertical axis separated from the vertical axis, a pair of inner corners located on the vertical axis side, and horizontal from the outer corner respectively A pair of first bulging parts bulging outward in the axial direction, and a pair of first bulging parts, Second pair of bulges into Flat Shaft outward
The first bulging portion is formed such that the bulging amount gradually increases as the opening is more distant from the vertical axis.
The swelling portion was formed such that the swelling amount gradually decreased as the opening distanced from the vertical axis.

Further, a shadow mask is formed by forming a plurality of vertical rows in which a plurality of substantially rectangular apertures are spaced apart in the vertical axis direction by a bridge portion and arranged at a predetermined pitch in the horizontal axis direction. There is a large hole in the surface of a mask material plate used for manufacturing a shadow mask having a plurality of holes each having a large hole opened on one surface of the shadow mask and a small hole opened on the other surface of the shadow mask. And a shadow mask baking master for baking a pattern corresponding to the small holes, having a large number of large hole patterns corresponding to the large holes, and a large hole original plate opposed to one surface of the mask material plate. Having a large number of small hole patterns corresponding to the small holes, and consisting of a small hole master opposed to the other surface of the mask material plate, the large hole pattern and the small hole pattern each having a rectangular main pattern. It was assumed to have a rectangular protrusion patterns protruding outward from the corners of the main pattern.

Furthermore, a plurality of substantially rectangular openings having different plane shapes depending on the coordinate position are provided, each of the plurality of openings being open on one surface of the shadow mask and the other of the shadow mask. A mask for baking a pattern corresponding to large holes and small holes on the surface of a mask material plate used for manufacturing a shadow mask having small holes opened on the surface of the mask, and a large hole pattern and In a method for manufacturing a shadow mask printing master having a rectangular main pattern having a small hole pattern and a rectangular protrusion pattern protruding outward from a corner of the main pattern, a rectangular main pattern is formed on a negative master. And a step of multiple-exposing a rectangular projecting pattern projecting outward at the corners of the main pattern and synthesizing it into a main pattern. The step of is to include the width of the protrusion pattern according to the coordinate position of the negative original, protruding length, the projecting angle and the step of changing the protruding position relative to the main pattern.

[0030]

As described above, a pair of bulging portions bulging outward in the horizontal axis direction are provided at a pair of outer corners apart from the vertical axis of the hole other than the hole on the vertical axis. If the opening is made gradually larger as the opening is more distant from the vertical axis, the shape of the opening when the opening is viewed from the direction of the electron beam path obliquely crossing the opening will increase with the increase in deflection. The shape can be a correct rectangle. As a result, a portion of the electron beam that crosses the opening diagonally hits the opening edge of the phosphor screen side or the inner wall of the opening and does not reach the phosphor screen. Can be eliminated, and deterioration of the brightness and white uniformity of the conventional rectangular hole shadow mask can be eliminated.

Particularly, in the case of a shadow mask in which both edges extending in the horizontal axis direction of the opening are linear and longer than the width in the horizontal axis direction at the center of the opening, the shadow diagonally crosses the opening as the deflection increases. The shape of the opening when the opening is viewed from the path direction of the electron beam can be made a more correct desired rectangular shape.

The openings on the vertical axis are symmetrical in the vertical and horizontal directions having bulging portions bulging outward from the four corners in the horizontal axis direction, and are separated from the vertical axis of the openings other than the openings on the vertical axis. A pair of first bulging outwards in the horizontal axis direction at a pair of outer corners
And a pair of second bulges bulging outward in the horizontal axis direction are provided at a pair of inner corners located on the vertical axis side, and the bulge of the first bulge is provided. If the amount of the second bulge is gradually increased as the aperture becomes more distant from the vertical axis, the amount of electrons that crosses the aperture diagonally as the deflection increases. The shape of the aperture when viewed from the beam path direction is almost a rectangular shape, and a part of the electron beam obliquely crossing the conventional aperture hits the opening edge of the phosphor screen side or the inner wall of the aperture and the phosphor screen Of the light-emitting region on the phosphor layer, which is caused by not reaching the pixel, and the deterioration of the luminance and the white uniformity of the conventional rectangular hole shadow mask can be eliminated. In addition, the central part of the phosphor screen has a larger landing margin of the electron beam with respect to the phosphor layer than the peripheral part, so the aperture on the vertical axis is made up and down and left and right symmetrical with four corners bulging left and right. In addition, the luminance at the center of the phosphor screen can be improved without causing color shift.

Further, in the original mask for baking a shadow mask, when the large hole pattern and the small hole pattern are composed of a rectangular main pattern and a rectangular protruding pattern which protrudes outward from a corner of the main pattern, the shadow is reduced. A desired amount of the corners of the opening of the mask can be bulged. By shaping this shadow mask and incorporating it into a color picture tube, the light-emitting area can be made substantially rectangular without chipping over the entire area of the phosphor screen. Can be.

Furthermore, when a rectangular main pattern and a protruding pattern which protrudes outward from a corner of the main pattern in a rectangular shape are synthesized by multiple exposure, a pattern having a required shape can be easily obtained.

[0035]

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

FIG. 4 shows an arrangement pattern of apertures of a rectangular aperture shadow mask according to one embodiment. The shadow mask is formed in a rectangular shape when viewed from the front, and has a vertical axis (Y axis) and a horizontal axis (X axis) passing through the center of the shadow mask.
Axis). This shadow mask has a large number of substantially rectangular openings 30, and the longitudinal axes of these openings 30 are formed so as to coincide with the vertical axis direction of the shadow mask. A plurality of apertures 30 are arranged on the vertical axis of the shadow mask via a bridge portion 31 having a narrow width, and a plurality of vertical rows 32 of apertures in the vertical axis direction are arranged in parallel at a predetermined pitch in the horizontal axis direction of the shadow mask. It is formed in an arranged pattern.

The opening 30 of the shadow mask is formed by a photo-etching method, and when incorporated in a color picture tube, a large opening is formed on the surface facing the phosphor screen.
A shape with a small hole opened on the surface on the side opposite to the electron gun, and with an overhanging portion that protrudes inward defining the size and shape of the opening 30 at the boundary where the large hole and the small hole match Is formed.

The planar shape of the opening 30 differs depending on the coordinate position on the shadow mask. As shown in FIG.
Regarding the vertical axis passing through the center of the shadow mask and the opening 30 near the vertical axis, the four corners 36L of the large hole 34 and the four corners 36S of the small hole 35 bulge outward by the same amount to the left and right. Accordingly, the four corners 36 of the opening 30 also bulge left and right, and are formed in a vertically symmetrical shape having substantially the same amount of bulges 37 bulging left and right.

On the horizontal axis of the shadow mask , x
= 0, the two corners of the large hole 34 on the shadow mask outer peripheral side as approaching the outer peripheral portion from the center of the shadow mask.
The bulging amounts of the two corners 36S on the outer peripheral side of the shadow mask 36L and the small holes 35, that is, the outer corners 36L and 36S to the left and right are increased. Along with this, the opening 30 has a pair of upper and lower bulges 37 bulging out to the left and right at substantially the same size at the outer corners 36, and these bulges 37 are close to the outer periphery of the shadow mask. The hole 30 is formed such that the swelling amount increases as the hole 30 increases. The two corners 36L and 36S of the large hole 34 and the small hole 35 on the center side of the shadow mask, ie, the inner corners
The swelling of 36L and 36S is maximum at the center of the shadow mask.
To the outer periphery of the shadow mask.
Hole 30 is formed so that it becomes smaller gradually, shadow
In the outermost opening 30 farthest from the center of the mask,
As shown in FIG. 2, the bulging of the inner corner 36 is almost
It is formed in an up-down symmetric left-right asymmetrical shape that has been reduced to a state where there is no such thing.

Further, on an intermediate axis, for example, a diagonal axis (D axis)
(See FIG. 4) In the above , the opening 30 closer to the outer peripheral portion from the center of the shadow mask of x = 0 is farther from the center of the shadow mask among the outer corners 36L and 36S of the large hole 34 and the small hole 35. Of the outer corners 36La, 36Lb, 36Sa, and 36Sb farther from the vertical axis of the shadow mask, outer corners 36La and 36Sa far from the horizontal axis are outer corners 36Lb and 36Sb closer to the horizontal axis of the shadow mask. It bulges outward more. Accordingly, of the outer corners 36 of the opening 30, the outer corner 36 far from the center of the shadow mask is closer to the outer corner 36.
It bulges outward more greatly, and a pair of upper and lower bulges 37 is formed at the outer corner of the opening 30. Large hole 34
Corners 36L, 36 of the shadow mask on the center side of the shadow mask
The swelling amount of S, that is, the inner corners 36L and 36S is set to be maximum on the vertical axis of the shadow mask, and
Opening 30 gradually separated from the vertical axis of the mask gradually
Smaller and the furthest away from the center of the shadow mask
At the outermost opening 30 on the square axis, as shown in FIG.
Outer side corners 36 reduced to almost no bulge
Of the corners 36La, 36Lb, 36Sa, 36Sb of the
Going on are formed in the shape of vertically asymmetrical.

As described above, the opening 30 of the shadow mask is formed.
The larger the opening 30 located in the horizontal axis direction from the center of the shadow mask, the larger the amount of swelling of the two outer corners increases, and the more the opening 30 is located in the vertical axis direction from the horizontal axis of the shadow mask. The opening 30 is formed such that the bulging amount of the corner portion on the side farther from the horizontal axis is larger than the outer corner portion on the horizontal axis side.

The distribution of the openings 30 having different shapes depending on the coordinate position of the shadow mask is symmetric with respect to the horizontal axis and the vertical axis, and has the same distribution in the four regions divided by the horizontal axis and the vertical axis.

The shape of each of the apertures 30, particularly the size of the bulging portion 37, varies depending on the type and size of the color picture tube, the thickness of the shadow mask, the size of the aperture 30, and the like. However, in general, the bulging amount (bulging length) of the bulging portion 37 is 30% of the width dimension (length in the horizontal axis direction) at the center of the opening 30.
It is better to do the following.

Further, as shown in FIG.
Is formed such that the width D of the straight portion of the side edge of the opening 30 adjacent to the bridge 31 is substantially equal to or larger than the width d of the center portion of the opening 30. Therefore, despite the fact that the corner 36 of the opening 30 is rounded,
A sufficient luminance can be obtained.

By forming the openings 30 as described above, it is possible to improve the brightness at the center of the phosphor screen corresponding to the center of the shadow mask, as compared with the conventional shadow mask. At the same time, the chipping of the light emitting area on the outer peripheral part of the phosphor screen is almost completely eliminated, and the deterioration of the brightness and white uniformity based on the chipping of the light emitting area generated on the outer peripheral part of the conventional phosphor screen can be sufficiently improved. .

That is, the phosphor screen of a color picture tube into which a shadow mask having a rectangular opening is usually incorporated is a striped three-color phosphor extending in the vertical axis direction corresponding to the row of openings of the shadow mask. Since the layers are composed of layers, the landing deviation of the electron beam with respect to the three-color phosphor layer has almost no problem in the vertical axis direction over the entire screen. However, horizontal landing deviation is a serious problem. However, since the landing margin in the horizontal axis direction at the central portion of the phosphor screen is usually sufficiently large, it protrudes left and right outward at the four corners 36 of the opening 30 at the central portion of the shadow mask as described above. Even if the bulging portion 37 is provided to increase the light emitting area, it is possible to prevent a color shift caused by landing the phosphor layer of another color.

On the other hand, with respect to the outer peripheral portion in the horizontal axis direction of the phosphor screen, the electron beam lands obliquely across the opening 30 in the peripheral portion in the horizontal axis direction of the shadow mask due to the deflection and lands on the phosphor layer. The tilt angle of the electron beam increases with an increase in deflection. The aperture 30 in the peripheral portion in the horizontal axis direction of the shadow mask through which the electron beam passing through the phosphor layer in the outer peripheral portion in the horizontal axis direction of the phosphor screen passes outward as shown in FIG. A bulging portion 37 is formed at the corner portion 36, so that the bulging portion 37 is vertically symmetric and left and right asymmetric. That is, as shown in FIGS. 5A and 5B, when viewed from the front, the aperture 30 is vertically symmetrical and left-right asymmetric. However, when the aperture 30 is viewed from the direction of the electron beam path, The bulge formed on the outer side, which is the outer peripheral side of the shadow mask, becomes invisible, and the corners 36 of the opening 30 are apparently sharpened and rounded. FIG. 1 (c)
As shown in (d), the position of the overhang portion 39 formed at the boundary where the large hole 34 and the small hole 35 coincide with each other in the shadow mask plate thickness direction is the long side portion and the short side portion of the opening 30. Differs from aperture 30
In the vicinity of the four corners, there is a step due to the protruding portion 39 of the long side and the short side. Therefore, as can be seen from FIGS. 5A and 5B, when viewed from the path direction of the electron beam, the inner wall 40 of the small hole looks wavy due to the overhang portion.
The shape of the hole 30 from the path direction of the electron beam is regulated by the opening edge 41 of the small hole. As a result, the light emitting region 43 on the phosphor layer can be approximated to a rectangle with no rounding and four rounded corners.

The opening 30 located away from the horizontal axis on the outer peripheral side in the vertical axis direction of the shadow mask is:
As described above, the position of the overhang formed at the boundary between the large hole 34 and the small hole 35 is different between the long side and the short side, and these steps are formed at the four corners of the opening. However, by forming the opening 30 into a vertically symmetric left and right asymmetric shape as shown in FIG. 3, when the opening 30 is viewed from the path direction of the electron beam, the opening 30 is formed on the outer peripheral side of the shadow mask. The swollen portion 37 is not visible, and the influence of the step at the corner of the opening of the overhang portion is eliminated, so that the corner becomes apparently acute and the roundness is reduced. On the other hand, the inside of the opening 30 has a vertically symmetric left-right asymmetric opening 30 shown in FIG. 2 due to a step at the opening corner of the overhang.
The inner wall of the small hole 35 looks wavy like
The opening shape of the electron beam from the path direction is regulated by the opening edge of the small hole. As a result, the light emitting region on the phosphor layer can be made close to a rectangle with no rounding and four rounded corners.

On the other hand, if the apertures on the horizontal axis and the intermediate axis of the shadow mask are outwardly bulged at the four corners similarly to the apertures 30 on and near the vertical axis shown in FIG. Assuming that the bulge is formed in a vertically symmetrical shape with protrusions, in this case, as shown in FIG. 6, when viewed from the path of the electron beam obliquely crossing the aperture 30a, the outer bulge is not visible. There is no problem as well as the opening on the horizontal axis and the intermediate axis of the shadow mask. However, a bulging portion 37 inside the opening 30a appears, and the opening 30a becomes noticeably deformed. As a result, the light emitting region 43 on the phosphor screen is also deformed into a shape having the swelling portion 44, and the swelling portion 44 causes the other color phosphor layer to emit light, causing a color shift and deteriorating the white uniformity. Further, for a phosphor screen having a stripe-shaped light absorbing layer between the three-color phosphor layers, the light absorbing layer cannot be formed in a straight line, causing problems such as uneven appearance.

Therefore, according to the shadow mask configured as described above, by changing the shape of the opening 30, particularly the swelling amount of the swelling portion 37, depending on the coordinate position, the light emission at the outer peripheral portion of the screen, which has conventionally occurred, is obtained. By eliminating the lack of the area, it is possible to prevent the luminance and the white uniformity from deteriorating, and it is possible to increase the luminance at the center of the screen without causing color shift. Therefore, the shadow mask of this example is thicker and has a larger radius of curvature than the shadow mask of the ordinary color picture tube, as well as the rectangular hole shadow mask of the ordinary color picture tube. When applied to a flat square pipe shadow mask that crosses the opening, a great effect can be obtained.

The openings 30 of the shadow mask having the above structure are formed by a photo-etching method. That is, a photosensitive agent is applied to both sides of the mask material plate to form a photosensitive agent coating,
A pair of masters for printing a shadow mask having a pattern corresponding to the opening to be formed are brought into close contact with the photosensitive agent coatings on both sides, and the pattern of the master is printed (exposed), developed, and developed. A resist pattern having an exposed portion of a mask material plate corresponding to the pattern of the original mask for baking a shadow mask is formed. Thereafter, the mask material plate on which the resist pattern is formed is etched by etching from both sides.

Next, the above-mentioned master for shadow mask baking and a method of manufacturing the same will be described.

As shown in FIGS. 7A and 7B, the original mask for baking a shadow mask is composed of an original plate 46a for forming small holes on one surface of the mask material and the other side of the mask material. A large hole original plate 46b for forming a large hole in the surface. The pair of small-hole and large-hole masters 46a, 46b
Has a small hole pattern 47a and a large hole pattern 47b, which will be described later, corresponding to substantially rectangular openings of a shadow mask having rectangular openings, respectively.
Are arranged in the vertical direction (Y-axis direction) of the original plates 46a and 46b via bridge portions 48a and 48b having a narrow width, and the arrangement in the vertical axis direction has a predetermined pitch in the horizontal axis direction (X-axis direction). They are arranged in columns.

As shown in FIG. 8A, the small hole pattern 47a includes a rectangular main pattern 50a and the main pattern 50a.
Protruding patterns 51a1, which are formed to protrude in a rectangular shape at the four corners of
51a2, 51a3, and 4514. Similarly, the large hole pattern 47b is made up of a rectangular main pattern 50b and protruding patterns 51b1, 51b2, 51b3, 51b4 which are formed in four corners of the main pattern 50b as shown in FIG. It is configured. These protruding patterns 51a1, 51a2,
51a3, 51a4 and 51b1, 51b2, 51b3, 51b4 are restricted in width, protrusion length, protrusion angle, and protrusion position. That is, as shown in FIGS. 9A to 9D, the main pattern of the small hole and large hole patterns is indicated by 50, and the protruding pattern is indicated by 51. When the thickness is less than 10 μm, the projection pattern 51 having a predetermined shape is not formed due to the lack of resolution of the photosensitive agent coating applied to the mask material, for example, the photosensitive agent coating composed of milk casein and dichromate, and a required aperture is obtained. I can't. Also 100
Above μm, the roundness of the corner of the opening becomes too large, making it impossible to obtain a light emitting region close to a rectangle. Therefore, the width W of the protruding pattern 51 is set in the range of 10 μm ≦ W ≦ 100 μm, preferably 20 μm ≦ W ≦ 80 μm.

Regarding the protruding length, when the thickness of the mask material is T and the protruding length Ly in the vertical axis direction is 0.5 T or more in both the small hole and large hole patterns, a desired etching time is obtained. The etching amount in the plate thickness direction in the inside is smaller in the middle part of the protruding pattern 51 than in the tip part of the protruding pattern 51 and the part near the main pattern 50, and it is possible to bulge the corners of the small holes and the large holes. Although it is possible, the corner of the opening cannot be bulged. for that reason,
The projection length Ly in the vertical axis direction is set in the range of 0 ≦ Ly ≦ 0.5T, preferably 0.1T ≦ Ly ≦ 0.4T. The protrusion length LX in the horizontal axis direction
Is inevitably determined if the projection length Ly in the vertical axis direction is determined.

Regarding the protruding angle, when the angle θ formed with the horizontal axis of the original plate is 90 ° or more, the bulging direction of the corner of the opening deviates from the intended direction, and the corner of the opening is rounded. Becomes too large, so that a light emitting area close to a rectangle cannot be obtained on the phosphor screen. Therefore, the protrusion angle θ is set in the range of 0 ° ≦ θ ≦ 90 °, preferably 10 ° ≦ θ ≦ 80 °.

Regarding the protruding position, the width of the rectangular main pattern 50 is defined as H, and the distance from the long side 52 of the rectangular main pattern 50 to the point where the center axis of the protruding pattern 51 intersects the short side 54 on the main pattern 50 side. When P is equal to or more than (1/2) H, since the protruding pattern 51 enters the inside of the main pattern 44 too much to form a hole of a predetermined shape, 0 ≦ P ≦ (1 / 2) H Preferably, it is set in the range of 0 ≦ P ≦ (3/8) H.

As the small hole and large hole patterns determined as described above, FIG. 8 shows the protruding patterns 51a1, 51a2, 51a.
3, 51a4 and 51b1, 51b2, 51b3, 51b4 are used as the main pattern 50a.
, 50b are arranged vertically symmetrical with respect to the horizontal axis (X axis) and asymmetrically arranged left and right with respect to the vertical axis (Y axis). However, in the master for baking a shadow mask used for forming the opening of the shadow mask described above, each main pattern is used.
With respect to 50a, 50b, the protruding patterns 51a1, 51a2, 51
a3, 51a4 and 51b1, 51b2, 51b3, 51b4 are arranged vertically and horizontally symmetrically, vertically symmetrically left and right asymmetrically, and vertically and horizontally asymmetrically. An optimal distribution is arranged for each area, and the distribution is symmetrical with respect to the horizontal axis and the vertical axis of the shadow mask printing master.

That is, in this example of the shadow mask printing master, the small hole pattern and the large hole pattern are vertically and horizontally symmetrical from the four corners of the main pattern on and near a vertical axis passing through the center of the shadow mask printing master. It has a protruding protruding pattern. Then, as the distance from the center of the original plate to the outer peripheral portion along the horizontal axis increases, the chipping of the light emitting area on the phosphor screen due to the collision of the electron beam obliquely across the opening of the shadow mask due to the increase in deflection is prevented. Therefore, the outer protruding pattern is vertically symmetrical left and right asymmetric, in which the outer protruding pattern is made larger than the inner protruding pattern.

For a pattern located on the intermediate axis, for example, a diagonal axis of the master for shadow mask printing, the outer protruding pattern farther from the center of the original protrudes more than the inner protruding pattern closer to the center of the original. It is vertically symmetric left and right asymmetric.

As a specific example, a master for printing a shadow mask of a 25-inch color picture tube will be described. In this master, the rectangular main pattern of the master for small holes has a length of 0.8 mm.
The width of the original is 0.11 mm at the center and 0.15 mm at the outer periphery in the horizontal axis direction of the original. On the other hand, the rectangular main pattern of the master for large holes has a length of 0.75 mm, a width of 0.33 mm at the center of the master, and a width of 0.525 mm at the outer periphery in the horizontal axis direction of the master. Projection patterns shown in Table 1 are formed at the four corners of each main pattern.

[0062]

[Table 1]

In Table 1, C, V,
H and D represent the center, the vertical axis end, the horizontal axis end, and the diagonal axis end of the shadow mask printing master, respectively.

FIG. 10 shows the positions of the center, the vertical axis end, the horizontal axis end, and the diagonal axis end of the shadow mask printing master when the small hole pattern 47a and the large hole pattern 47b are correctly overlapped. 5 shows an overlapping state of the small hole pattern 47a and the large hole pattern 47b.

Such an original mask for baking a shadow mask is drawn using a drawing machine (for example, a photo plotter manufactured by Gerber, USA) capable of drawing a rectangular pattern. That is, the original for small holes is manufactured as shown in FIG. First, as shown in FIG. 3A, a negative master is exposed to a rectangular main pattern 50a having a length sL and a width sw. Next, as shown in (b), a protruding pattern 51a1 having a width sw1 is protruded at the first corner of the main pattern 50a from the horizontal axis so as to protrude sb1 in the length direction of the main pattern 50a and sa1 in the width direction. To expose at an angle sk1. Next, as shown in (c), the projecting pattern 51a2 having a width sw2 is formed at the second corner of the main pattern 50a at an angle with respect to the horizontal axis so as to project sb2 in the length direction of the main pattern 50a and sa2 in the width direction. Exposure at sk2. Next, as shown in (d), the width s is set at the third corner of the main pattern 50a.
The protrusion pattern 51a3 of w3 is s in the length direction of the main pattern 50a.
b3, angle s with respect to the horizontal axis to protrude sa3 in the width direction
Exposure at k3. Further, as shown in (e), the projecting pattern 51a4 having a width sw4 is formed at the fourth corner of the main pattern 50a at an angle to the horizontal axis so as to project sb4 in the length direction of the main pattern 50a and sa4 in the width direction. Exposure at sk4. As a result, a latent image of one small hole pattern is formed. This main pattern 50
a and the protruding pattern 51a to this main pattern 50a
Exposure of 1, 51a2, 51a3, and 51a4 is repeated over the entire area of the negative master, and then development is performed to produce a required master for small holes.

The large hole original plate is also manufactured by the same method. That is, as shown in FIG. 12A, first, a rectangular main pattern having a length LL and a width Lw is formed on a negative master.
Expose 50b. Next, as shown in (b), a protruding pattern 51b1 having a width Lw1 is formed at a first corner of the main pattern 50b with respect to the horizontal axis so as to protrude Lb1 in the length direction of the main pattern 50b and La1 in the width direction. To expose at an angle Lk1. Next, as shown in (c), the width L is set at the second corner of the main pattern 50b.
The protruding pattern 51b2 of w2 is L in the length direction of the main pattern 50b.
b2, an angle L with respect to the horizontal axis so as to protrude La2 in the width direction
Exposure at k2. Next, as shown in (d), the projecting pattern 51b3 having a width Lw3 is formed at the third corner of the main pattern 50b at an angle with respect to the horizontal axis so as to project Lb3 in the length direction of the main pattern 50b and La3 in the width direction. Exposure is performed with Lk3. (E)
As shown in (1), the main pattern 50b is exposed at an angle Lk4 with respect to the horizontal axis so that the protruding pattern 51b4 having a width Lw4 protrudes Lb4 in the length direction and La4 in the width direction at the fourth corner of the main pattern 50b. Exposure of such a main pattern 50b and protruding patterns 51a1, 51b2, 51b3,
After the exposure of 51b4 is repeated over the whole area of the negative master, the necessary large-hole master is manufactured by developing.

When the original mask for baking a shadow mask manufactured as described above is used, a shadow mask in which the bulging portion 37 protrudes differently depending on the coordinate position of the shadow mask as shown in FIGS. Can be manufactured.

Further, according to the method of manufacturing a master for baking a shadow mask, a required master for baking a shadow mask can be easily manufactured.

Next, another embodiment will be described.

In the above embodiment, the shadow mask has a configuration in which the openings located on the vertical axis of the shadow mask and in the vicinity thereof have bulging portions at the four corners.
As shown in FIG. 13, the large hole 34, the small hole 35, and the opening 30 may be formed in a rectangular shape without bulging portions at four corners. Even when such openings 30 are formed, the large hole pattern and the small hole pattern of the shadow mask printing master project from the four corners of the main pattern so that the four corners of the formed openings 30 are not rounded. One having a projected pattern is used.

Further, in the above-described embodiment, one of the outer corners, which is farther away from the horizontal axis, has a larger bulging amount than the other corner which is closer to the horizontal axis. It has an asymmetric shape with many vertical and horizontal sides. However, depending on the type of color picture tube, the amount of swelling at the corner of the aperture is changed without considering the distance from the horizontal axis but only the distance in the horizontal axis direction from the center of the shadow mask. Is also good. That is, the shape of all apertures in a vertical row crossing the horizontal axis of the shadow mask may be the same as the shape of the aperture on the horizontal axis of each vertical row parallel in the horizontal axis direction.

Further, in the above-described embodiment, the shadow mask in which the central portion of the short side and the long side of the large hole is linear and the corner portion is bulged has been described.
As shown in FIG. 14, the central portion of the short side 53 may have a shape bulging in the direction of the opening 30. As shown in FIG. 15, the central portion of the short side 53 is swelled in the direction of the opening 30, and the central portion of the long side 54 corresponding to the side of the opening 30 where the bulging portion 37 is formed is oriented in the direction of the opening 30. It may be a swelled shape.

Further, with respect to the original master for shadow mask printing, in the above-mentioned embodiment, the latent images of the required small hole and large hole patterns are formed by synthesizing the protruding patterns at the four corners of one main pattern. By repeating the process, small-hole and large-hole masters were produced. However, as a method of manufacturing an original master for shadow mask baking, as shown in FIG. 16A, all the main patterns 50a and 50b are exposed in advance, and then, as shown in FIG. 50a,
A projection pattern 51a1 or 51b1 (not shown) is exposed on the first corner of 50b. Then, as shown in (c) to (d), the protruding patterns 51a2 to 51a4 or 51b2 to 51b are sequentially formed at the second to fourth corners of the main patterns 50a and 50b.
It can also be manufactured by a method of exposing b4 (not shown).

Further, in the above embodiment, when the small-hole original plate and the large-hole original plate are correctly superimposed on the mask material, the smaller the smaller the distance from the center of the shadow mask toward the outer peripheral portion in the vertical axis direction and the horizontal axis direction, the smaller the smaller the original. Although an original mask for baking a shadow mask for manufacturing an off-center type shadow mask in which the large holes are shifted to the outside with respect to the holes has been described, the present invention provides that all small hole patterns and large hole patterns are completely coaxial. The invention can also be applied to a pair of shadow mask baking originals.

[0075]

As described above, in a shadow mask having a large number of substantially rectangular openings arranged in a predetermined pattern, the shape of the opening, in particular, the expansion bulging outward in the horizontal axis direction according to the coordinate position of the shadow mask. As the amount of bulge of the protruding portion increases in the horizontal axis direction from the center of the shadow mask to the outer peripheral portion, the amount of bulge of the bulge outside the hole increases. When the aperture is viewed from the path direction of the traversing electron beam, the shape of the aperture can be made correct and substantially rectangular, so that a part of the electron beam obliquely traversing the aperture conventionally has a phosphor screen side opening edge. The luminous area on the phosphor layer, which is caused by not reaching the phosphor screen by colliding with the inner wall of the aperture, can be eliminated, and the brightness and white uniformity of the conventional rectangular hole shadow mask do not deteriorate. Succoth can.

Particularly, in the case of a shadow mask in which both edges extending in the horizontal axis direction of the aperture are linear and longer than the horizontal width at the center of the aperture, the electrons obliquely cross the aperture with increasing deflection. The shape of the opening when the opening is viewed from the beam path direction can be made a more correct desired rectangular shape. Thereby, the shape of the light emitting region on the phosphor layer can be made better, and the luminance and white uniformity can be further improved.

The openings on the vertical axis passing through the center of the shadow mask are symmetrical in the vertical and horizontal directions with bulges bulging outward from the four corners in the horizontal axis direction. The bulging amount of the pair of first bulging portions bulging outward in the horizontal axis direction from the pair of outer corners distant from the vertical axis of the hole is increased as the opening distance from the vertical axis increases, and When the amount of swelling of the pair of second swelling portions swelling outward in the horizontal axis direction at the pair of inner corners located gradually decreases as the opening becomes more distant from the vertical axis, the opening increases as the deflection increases. When the opening is viewed from the direction of the electron beam obliquely crossing the hole, the shape of the opening when viewed from the direction of the hole is corrected to a substantially rectangular shape. Above the phosphor layer caused by hitting the inner wall of the hole and not reaching the phosphor screen It is possible to eliminate the lack of light area,
The brightness and white uniformity of a conventional shadow mask having a rectangular opening can be prevented from deteriorating.
Moreover, the landing margin of the electron beam with respect to the phosphor layer is larger in the central portion of the phosphor screen than in the peripheral portion, and the luminance of the central portion of the phosphor screen can be improved without causing color shift.

Further, in the original mask for baking a shadow mask, when the large hole pattern and the small hole pattern are composed of a rectangular main pattern and a rectangular projecting pattern protruding outward from a corner of the main pattern, the shadow is formed. A desired amount of the corners of the opening of the mask can be bulged. By shaping this shadow mask and incorporating it into a color picture tube, the light-emitting area can be made substantially rectangular without chipping over the entire area of the phosphor screen. Can be.

Furthermore, when a rectangular main pattern and a protruding pattern protruding outward in a rectangular shape from a corner of the main pattern are synthesized and formed by multiple exposure, a pattern having a required shape can be easily formed.

[Brief description of the drawings]

FIG. 1A is a plan view showing a shape of a large hole on a vertical axis of a shadow mask according to an embodiment of the present invention.
(B) is a plan view showing the shape of the small hole on the vertical axis, FIG.
(C) is a cross-sectional view of the large hole in FIG.
FIG. 1D is a DD sectional view of the large hole in FIG.

FIG. 2A is a plan view showing a shape of a large hole on a horizontal axis of a shadow mask according to one embodiment of the present invention;
FIG. 2B is a plan view showing the shape of a small hole on the horizontal axis of the shadow mask.

FIG. 3A is a plan view showing a shape of a large hole on a diagonal axis of the shadow mask according to the embodiment of the present invention;
FIG. 3B is a plan view showing the shape of a small hole on the diagonal axis of the shadow mask.

FIG. 4 is a diagram showing an arrangement pattern of substantially rectangular openings of a rectangular hole shadow mask.

FIGS. 5 (a) and 5 (b) show the shape of the opening and the phosphor when viewed from above the opening in the peripheral portion in the horizontal axis direction along the path of the electron beam obliquely crossing the opening. FIG. 4 is a diagram for explaining a relationship with a light emitting region on a layer.

FIG. 6 is a view for explaining the relationship between the shape of the aperture and the light emitting area on the phosphor layer when viewed from the path direction of the electron beam obliquely crossing the aperture having bulges at the four corners. .

FIG. 7A is a diagram showing an arrangement of small hole patterns of a small hole original plate of a shadow mask printing original plate according to an embodiment of the present invention, and FIG. It is a figure which shows arrangement | positioning of the large hole pattern of the master for large holes.

FIG. 8A is a view showing a shape of a small hole pattern of a shadow mask printing master according to one embodiment of the present invention;
FIG. 8B is a diagram showing the shape of the large hole pattern of the shadow mask printing original plate.

9 (a) to 9 (d) show the width and length of the small hole pattern and the large hole pattern, respectively.
FIG. 4 is a diagram for explaining a protruding angle and a protruding position with respect to a main pattern.

10 (a) is a view showing a state where a small hole pattern and a large hole pattern are matched at the center of the master for shadow mask printing, and FIG. 10 (b) is a vertical axis end of the master for shadow mask printing. FIG. 10C is a view showing a state where the small hole pattern and the large hole pattern in the portion match each other, and FIG. 10C shows a state where the small hole pattern and the large hole pattern at the end of the horizontal axis of the shadow mask printing original plate are matched. FIG. 1, FIG.
0 (d) is a diagram showing a state where the small hole pattern and the large hole pattern at the diagonal axis end of the shadow mask printing master are matched.

FIGS. 11A to 11E are views for explaining a method of forming a small hole pattern of a master for shadow mask printing.

12 (a) to 12 (e) are views for explaining a method of forming a large hole turn of a master for baking a shadow mask.

FIG. 13 (a) is a view for explaining a different original mask for baking a shadow mask according to another embodiment of the present invention. FIG. 13B is a plan view showing small holes of the opening of the shadow mask having no bulges at the four corners.

FIG. 14 is a plan view showing openings of different shadow masks according to another embodiment of the present invention.

FIG. 15 is a plan view showing openings of still another shadow mask according to another embodiment of the present invention.

FIGS. 16 (a) to 16 (e) are views for explaining another method of forming a small hole pattern and a large hole pattern of a shadow mask printing original plate according to another embodiment of the present invention. .

FIG. 17 is a diagram showing the overall configuration of a color picture tube.

18 (a) is a plan view showing a substantially rectangular opening of a shadow mask of a conventional color picture tube; FIG.
18B is a sectional view taken along line BB of the opening in FIG. 18A, and FIG. 18C is a sectional view taken along line C-C of the opening in FIG.

FIG. 19 is a view for explaining the relationship between the conventional aperture shown in FIG. 18 and an electron beam obliquely crossing the aperture.

FIG. 20 is a development view for explaining an overhang portion formed at a boundary between a large hole and a small hole of a substantially rectangular opening of a conventional shadow mask.

FIG. 21 is a view for explaining a relationship between a substantially rectangular opening of a conventional shadow mask and a light emitting region formed on a phosphor layer by an electron beam obliquely crossing the opening.

FIG. 22 (a) is a plan view showing the shape of an opening at the center of a conventional off-center type shadow mask; FIG.
(B) is the BB sectional view.

FIG. 23 (a) is a plan view showing an opening in the outer peripheral portion in the horizontal axis direction of a conventional off-center type shadow mask, and FIG. 23 (b) is a BB cross-sectional view thereof.

FIG. 24 (a) is a plan view showing a hole at an outer peripheral portion in a diagonal axis direction of a conventional off-center type shadow mask, FIG. 24 (b) is a BB cross-sectional view thereof, and FIG. ) Is the C
It is -C sectional drawing.

FIG. 25 is a view for explaining a relationship between an opening of a conventional shadow mask for a flat square tube and an electron beam obliquely crossing the opening.

26 (a) is a plan view showing an aperture of a shadow mask improved to solve the problem of a substantially rectangular aperture of a conventional shadow mask, and FIG. 26 (b) is a plan view of FIG.
26A is a sectional view taken along line BB of the opening in FIG. 26A, and FIG. 26C is a sectional view taken along line CC of the opening in FIG.

27 (a) is a plan view of a substantially rectangular opening for solving the problem of the shadow mask shown in FIG. 26, and FIG. 27 (b) is BB in FIG. 27 (a). FIG. 27C is a cross-sectional view taken along a line CC in FIG. 27A.

FIGS. 28 (a) and (b) are plan views each showing an opening of a shadow mask improved to solve the problem of the substantially rectangular opening of the conventional shadow mask.

FIG. 29 is a plan view showing apertures of different shadow masks which have been improved to solve the problem of the substantially rectangular apertures of the conventional shadow mask.

FIG. 30 is a view showing a pattern of an original mask for baking a shadow mask for forming openings of a shadow mask improved to solve the problem of the substantially rectangular openings of the conventional shadow mask.

FIG. 31 is a plan view showing still another opening of a shadow mask improved to solve the problem of the substantially rectangular opening of the conventional shadow mask.

FIG. 32 (a) is a view showing another different opening shape of a shadow mask improved to solve the problem of the substantially rectangular opening of the conventional shadow mask, and FIG. 3;
FIG. 2 (b) is a view showing a pattern of an original mask for baking a shadow mask which forms the opening.

FIG. 33 is a view showing a pattern of still another original mask for baking a shadow mask which is improved to solve the problem of the substantially rectangular opening of the conventional shadow mask.

[Explanation of symbols]

 30 ... opening 31 ... bridge 32 ... vertical row 34 ... large hole 35 ... small hole 36 ... corner 36L ... four corners of the big hole 36S ... four corners of the small hole 37 ... bulging part 39 ... projection part 46a ... small Hole master 46b… Large hole master 47a… Small hole pattern 47b… Large hole pattern 50a, 50b… Rectangular main pattern 51a1,50a2,51a3,50a4… Projection pattern 51b1,50b2,51b3,50b4… Projection pattern

──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 2-320427 (32) Priority date November 22, 1990 (November 22, 1990) (33) Priority claim country Japan (JP) (56) References JP-A-1-320738 (JP, A) JP-A-55-138757 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 29/07 H01J 9 / 14

Claims (5)

(57) [Claims] 1. A substantially rectangular plate having a vertical axis passing through the center and a horizontal axis passing through the center, and formed by a plurality of substantially rectangular plate- like intermediate portions arranged in a predetermined pattern. In a shadow mask having openings, each of the openings has a longitudinal axis substantially parallel to the vertical axis, and the openings are formed by a vertical row in which a plurality of openings are arranged in parallel with the vertical axis. A plurality of openings other than the openings on the vertical axis are arranged in such a manner that a plurality of openings are arranged side by side at a predetermined pitch in the horizontal axis direction. A pair of outer corners in which the hole is separated from the vertical axis, a pair of inner corners located on the vertical axis side, and a pair of bulges each bulging outward in the horizontal axis direction from the outer corner. The swelling amount gradually increases as the swelling portion becomes more distant from the vertical axis. A shadow mask characterized by being formed so as to be sharp. 2. Each of the openings has both ends defined by a bridge portion, the both ends extending in the horizontal axis direction, and both ends are longer than the width in the horizontal axis direction at the center of the opening. The shadow mask according to claim 1, wherein the shadow mask has a shape. 3. It is formed in a substantially rectangular shape, has a vertical axis passing through the center and a horizontal axis passing through the center, and is formed by a large number of substantially rectangular plate thickness middle portions arranged in a predetermined pattern. In a shadow mask having openings, each of the openings has a longitudinal axis substantially parallel to the vertical axis, and the openings are formed by a vertical row in which a plurality of openings are arranged in parallel with the vertical axis. A plurality of holes are arranged so as to be formed side by side at a predetermined pitch in the horizontal axis direction, adjacent holes in each vertical column are separated in the vertical axis direction by a bridge portion, and each hole on the vertical axis is four corners. A pair of outer corners formed in a vertically symmetrical shape having a swelling portion swelling outward in the horizontal axis direction from the portion, and an opening other than the opening on the vertical axis separated from the vertical axis. A pair of inner corners located on the vertical axis side,
A pair of first bulges each bulging outward in the horizontal axis direction from the outer corner, and a pair of second bulges each bulging outward in the horizontal axis direction from the inner corner. The first swelling portion is formed so that the swelling amount gradually increases as the opening distances away from the vertical axis, and the second swelling portion increases as the opening distances away from the vertical axis. A shadow mask characterized in that the swelling amount is gradually reduced. 4. A shadow mask formed by forming a plurality of vertical rows in which a plurality of substantially rectangular openings are spaced apart in the vertical axis direction by a bridge portion and arranged at a predetermined pitch in the horizontal axis direction. A plurality of openings each having a large hole opened on one side of the shadow mask and a small hole opened on the other side of the shadow mask. An original mask for baking a shadow mask for printing a pattern corresponding to a hole and a small hole, wherein the large hole pattern has a large number of large hole patterns corresponding to the large holes and is provided on one surface of the mask material plate. An original plate, comprising a plurality of small hole patterns corresponding to the small holes, a small hole original plate opposed to the other surface of the mask material plate, wherein the large hole pattern and the small hole pattern are each rectangular; Lord of According to the turn, characterized in that it has a rectangular protrusion patterns protruding outward from the corners of the main pattern
Create the shadow mask according to any one of Items 1 to 3.
A master for baking shadow masks. 5. A plurality of substantially rectangular openings having different planar shapes depending on coordinate positions, each of which has a large opening opened on one surface of the shadow mask and the other opening of the shadow mask. A shadow mask baking master for baking a pattern corresponding to the large holes and small holes on the surface of a mask material plate used for manufacturing a shadow mask having small holes opened on the surface, the large hole pattern and In a method for manufacturing a shadow mask printing master having a rectangular main pattern having a small hole pattern and a rectangular protrusion pattern protruding outward from a corner of the main pattern, the negative master includes the rectangular main pattern. Exposing the pattern;
A step of multiple-exposing a rectangular projecting pattern projecting outward at a corner of the main pattern and synthesizing the main pattern with the main pattern, and the synthesizing step is performed according to the coordinate position of the negative master. 4. The method according to claim 1 , further comprising a step of changing a width, a protruding length, a protruding angle, and a protruding position of the pattern with respect to the main pattern.
A method for producing a master for baking a shadow mask for producing the shadow mask according to any one of the first to third aspects .