JP2005251531A - Color picture tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color picture tube capable of maintaining a vibration preventing effect with an auxiliary mask and preventing generation of bright and dark patterns of a phosphor screen. <P>SOLUTION: A shadow mask 8 is such that an auxiliary mask 15 is fixed so as to be overlapped with a part of a mask main body 14, a position of an electron beam passing hole 27 of the mask main body 14 and a position of an electron beam passing hole of the auxiliary mask 15 correspond to each other. When a transmission rate distribution to a phosphor screen side of the electron beam of the mask main body 14 itself is observed about a horizontal direction of the screen, a boundary part 50 between a part at which the auxiliary mask 15 is fixed and a part at which the auxiliary mask 15 is unfixed is discontinued, and the transmission rate reducing towards the center from both ends of the shadow mask 8 is once increased at the discontinuous part. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a color picture tube provided with a shadow mask used for televisions, computer displays and the like.

  In general, a color picture tube includes an envelope having a panel on which a phosphor screen is formed, and a substantially rectangular shadow mask provided in the envelope so as to face the phosphor screen. The phosphor screen is formed on the inner surface of the panel, and is formed with, for example, a striped three-color phosphor layer that emits blue, green, and red light and a black light shielding layer.

  On the perforated surface facing the phosphor screen of the shadow mask, a large number of apertures as electron beam passage apertures are formed in a predetermined arrangement. The shadow mask has a function of selecting three electron beams emitted from the electron gun through the respective apertures and making them enter the three-color phosphor layers constituting the phosphor screen.

  To form a stripe-type color phosphor screen, first, a photosensitive film is applied to the inner surface of the panel and dried. Thereafter, stripe-shaped exposure regions are formed in the photosensitive film by ultraviolet rays emitted from an exposure light source and passed through a large number of slot-shaped openings provided with a color selection mechanism. Next, a phosphor layer is formed by exposure means substantially the same as described above.

  In recent years, in order to reduce external light reflection and reduce image distortion to improve visibility, flat tubes having a substantially flat surface with a radius of curvature of the outer surface of the color picture tube panel of 10,000 mm or more are becoming mainstream. is there. Usually, the perforated surface of the shadow mask facing the phosphor screen is formed in a shape corresponding to the shape of the inner surface of the panel. For this reason, the shadow mask of the flat tube has a smaller curvature than the conventional color picture tube and is almost flattened. However, when such a shadow mask with a small curvature is used, the following problems occur.

  Usually, the shadow mask is formed of a metal plate having a thickness of about 0.2 mm. When the curvature of the perforated surface is small, the shadow mask for a large screen formed of such a thin plate is deformed by its own weight or external force, and it becomes difficult to maintain the mask curved surface. That is, when the curvature of the perforated surface is reduced, the holding force of the mask curved surface (hereinafter, mask curved surface strength) is reduced. In particular, the decrease in the strength of the mask curved surface is most noticeable at the center of the perforated surface, that is, near the screen center.

  When the mask curved surface strength is low, the perforated surface of the shadow mask is deformed by a minute external force during manufacture or transportation. In this case, the distance relationship between the electron beam passage hole of the shadow mask and the inner surface of the panel fluctuates, and the electron beam emitted from the electron gun does not land on the predetermined phosphor layer, causing a color shift.

  In addition, even if the mask curved surface strength does not reach the deformation of the shadow mask, the mask perforated surface is likely to resonate due to vibrations such as sound when incorporated in a television set, and unnecessary brightness and darkness are displayed on the screen. Will be projected.

  The simplest method for preventing such a decrease in mask curved surface strength is to increase the thickness of the shadow mask. However, when the thickness of the shadow mask plate increases, it becomes difficult to control the etching at the time of manufacturing the shadow mask, and the variation in the hole diameter of the electron beam passage hole increases. As a result, the yield decreases at the time of manufacturing the shadow mask and the color picture tube, and the quality of the screen deteriorates.

  As a technique for solving these problems, a shadow mask formed of a mask body and a belt-like auxiliary mask has been proposed (see Patent Document 1 below). The mask main body having this configuration has a substantially rectangular perforated portion in which a large number of electron beam passage holes are formed so as to face almost the entire surface of the phosphor screen. The auxiliary mask is fixed in the vicinity of the short axis of the perforated portion of the mask body, and has a number of electron beam passage holes corresponding to the electron beam passage holes of the mask body, with the short axis as the longitudinal direction. It is a strip-shaped mask.

According to the shadow mask formed of such a mask main body and a belt-like auxiliary mask, the strength near the minor axis is improved, so that the mask curved surface strength of the shadow mask can be improved. In this configuration, the size of the light beam incident from the electron gun side is determined by the opening of the mask body, and the size of the opening of the auxiliary mask is sufficiently larger than the opening of the mask body to be closely fixed and has a light passage margin It has a structure. For this reason, when the light beam passes through the opening of the auxiliary mask, it strikes a predetermined panel inner surface position without colliding with the auxiliary mask (portion where there is no opening).
JP 2002-197989 A

  However, the shadow mask formed of the mask body and the auxiliary mask as described above has the following problems. The light beam that has passed through the aperture of the mask main body collides with the aperture side wall of the mask main body, and a plurality of weak light amounts are scattered in a direction different from the light incident direction and pass through the mask main body. In this case, the amount of light transmitted through the mask body has a continuous transmittance distribution in the horizontal direction depending on the mask opening.

  On the other hand, in the portion where the auxiliary mask is in close contact, the light scattered light when passing through the light collides with the aperture side wall of the auxiliary mask, and the amount of transmitted light after passing through the auxiliary mask decreases.

  For this reason, when the stripe-shaped black light shielding layer is formed, the portion having the auxiliary mask has a lower amount of passing ultraviolet light than the portion having no auxiliary mask. For this reason, the phenomenon that the stripe-shaped phosphor layer facing the auxiliary mask is formed with a stripe width smaller than a predetermined size occurs.

  In this case, when the stripe-shaped phosphor layer is viewed over the entire panel, a light-and-dark pattern is produced in which the phosphor layer facing the auxiliary mask has dark stripe transmitted light and is bright in other areas. That is, there arises a problem that a bright / dark boundary is generated in the phosphor layer facing the boundary of whether or not the auxiliary mask is fixed, thereby degrading the quality of the phosphor layer.

  In order to achieve the above object, a first color picture tube of the present invention comprises a phosphor screen and a shadow mask disposed opposite to the phosphor screen and formed with an electron beam passage hole, The shadow mask has an auxiliary mask fixed so as to overlap a part of the mask body, and the position of the electron beam passage hole of the mask body corresponds to the position of the electron beam passage hole of the auxiliary mask, When the transmittance distribution of the electron beam of the mask main body alone toward the phosphor screen is seen in the horizontal direction of the screen, there is no difference between the portion where the auxiliary mask is fixed and the boundary portion between the portion where the auxiliary mask is not fixed. It is continuous, and in the discontinuous portion, the transmittance that has decreased from the both ends of the shadow mask toward the center is once increased. And butterflies.

A first color picture tube of the present invention comprises a phosphor screen and a shadow mask disposed opposite to the phosphor screen and formed with an electron beam passage hole. The shadow mask is a part of the mask body. The auxiliary mask is fixed so as to overlap the portion, and the position of the electron beam passage hole of the mask body corresponds to the position of the electron beam passage hole of the auxiliary mask, and the auxiliary body of the mask body Among the portions adjacent to the boundary between the portion where the mask is fixed and the portion where the auxiliary mask is not fixed, the opening width in the horizontal direction of the screen of the mask body in the portion where the auxiliary mask is fixed is the auxiliary mask. The opening width in the horizontal direction of the screen of the mask body in the unfixed portion of the mask is larger.

  According to the present invention, while maintaining the vibration preventing effect of the auxiliary mask, the generation of a light / dark pattern between the phosphor screen facing the portion with the auxiliary mask and the phosphor screen facing the portion without the auxiliary mask is generated. Can be prevented.

  In the present invention, the amount of transmitted light in the portion of the mask body where the auxiliary mask is fixed is increased, so that the amount of light lost when the electron beam passes through the auxiliary mask can be compensated. It is possible to prevent the occurrence of a bright and dark pattern between the opposing phosphor screen and the phosphor screen facing the portion without the auxiliary mask. That is, while maintaining the vibration preventing effect of the auxiliary mask, it is possible to prevent the occurrence of a bright and dark pattern on the phosphor screen due to insufficient transmitted light quantity of the auxiliary mask portion.

  In the first color picture tube of the present invention, the opening width in the horizontal direction of the screen of the mask main body in the portion where the auxiliary mask is fixed among the portions adjacent to the boundary portion of the mask main body, It is preferable that the opening width in the horizontal direction of the screen of the mask main body is larger than the width of the mask in the portion where the auxiliary mask is not fixed.

  Further, among the portions adjacent to the boundary portion of the mask body, the opening width in the horizontal direction of the screen of the mask body in the portion where the auxiliary mask is fixed is the width of the mask body in the portion where the auxiliary mask is not fixed. It is preferably 1.05 times or more and 1.2 times or less than the opening width in the horizontal direction of the screen.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a color picture tube according to an embodiment of the present invention. FIG. 2 is a perspective view of the shadow mask 8 shown in FIG. 1 and 2, Z is a tube axis, which is an axis passing through the center of the panel 2 and the center of the neck 4. X is a long axis (horizontal axis), which is an axis extending in the horizontal direction perpendicular to the tube axis. Y is a short axis (vertical axis), and is an axis extending perpendicular to the tube axis Z and the long axis Y. The X-axis direction is the horizontal screen direction, and the Y-axis direction is also the vertical screen direction. Note that the meanings of X, Y, and Z are the same in the following drawings.

  In FIG. 1, the envelope 1 is made of a glass material, and includes a panel 2, a funnel 3 joined to a skirt portion 2 a of the panel 2, and a neck 4 extending from a small diameter portion of the funnel 3. Yes. The outer surface 2b of the panel 2 is substantially rectangular and has a radius of curvature of 10,000 mm or more and is a substantially flat surface. On the inner surface 2c of the panel 2, a phosphor screen 5 including a striped black light shielding layer is formed.

A shadow mask structure 6 that is a color selection electrode structure is disposed in the envelope 1 so as to face the phosphor screen 5. This shadow mask structure 6 is formed by bonding the peripheral portion of the shadow mask 8 to the mask frame 9. The mask frame 9 has a rectangular frame shape, and each side has an L-shaped cross section. The shadow mask structure 6 is supported on the inner surface of the panel 2 by engaging an elastic support 10 provided on the side wall of the mask frame 9 with a stud pin 11 embedded in the skirt portion 2 a of the panel 2.

  An electron gun 12 that emits three electron beams arranged in-line in the major axis X direction is disposed in the neck 4. In this case, the electron beam emitted from the electron gun 12 is deflected by the deflection yoke 13 attached to the outside of the funnel 3 and is scanned horizontally and vertically on the phosphor screen 5 through the shadow mask structure 6. As a result, an image is displayed.

  Next, the shadow mask 8 will be described in detail with reference to FIG. The shadow mask 8 includes a mask main body 14 and an auxiliary mask 15 attached to the mask main body 14 and has a partially double structure. The auxiliary mask 15 is attached to the surface of the mask main body 14 (phosphor screen 5 side). Further, the attachment range is in the vicinity of the short axis Y axis.

  A perforated portion 16 is formed in a substantially rectangular region of the mask body 14 with the major axis X direction as a horizontal side and the minor axis Y direction as a vertical side. A non-perforated portion 17 is formed on the outer periphery of the perforated portion 16 so as to surround the perforated portion 16. As shown in the enlarged view of the portion A, a large number of apertures 7 through which the electron beam passes are formed in the perforated portion 16 by a chemical etching technique. The non-perforated portion 17 is formed with a non-hole portion 18 in which the opening 7 is not formed and a skirt portion 19 formed by bending an outer peripheral portion of the non-hole portion 18 and extending in the tube axis Z direction.

  As shown in the enlarged view of the portion A, the apertures 7 provided in the perforated portion 16 form an aperture row extending linearly in the minor axis Y direction. A large number are arranged in the axis X direction at a predetermined arrangement pitch PH. In each aperture row, there is a bridge 20 between apertures adjacent in the minor axis Y direction. An opening 27 corresponding to the opening 7 of the mask body 14 is formed in the auxiliary mask 15.

  FIG. 3A is a cross-sectional view of the shadow mask shown in FIG. 2 in the minor axis Y direction. FIG. 3A shows a state in which the auxiliary mask 15 is overlapped over the entire minor axis Y direction of the mask body 14. The auxiliary mask 15 is provided with a perforated portion 24 (shaded portion) and a non-perforated portion 25. The non-perforated portion 25 is formed outside both ends of the perforated portion 24 in the minor axis Y direction. The non-perforated portion 25 is formed with a skirt portion 26 that is bent so as to overlap the skirt portion 19 of the mask main body 14. The mask main body 14 and the auxiliary mask 15 are closely fixed by laser welding at a portion of the auxiliary mask 15 where the perforated portion 24 avoids the opening 27 and the non-perforated portion 25.

  FIG. 3B is a cross-sectional view in the major axis X direction of the shadow mask shown in FIG. As shown in the figure, the auxiliary mask 15 is attached in the vicinity of the Y axis of the mask body, and the width in the major axis X direction is W in the example of the figure.

  FIG. 4 is a schematic view of an exposure apparatus 60 used for forming a striped black light shielding layer. In the exposure device 60, a mercury lamp 62 that emits exposure light (ultraviolet rays) is cooled in the lamp house 63 with water. The exposure light beam passes through a correction lens 61 that corrects the ray trajectory, and strikes a predetermined position on the inner surface of the panel 2 through the hole of the shadow mask 8. The inner surface of the panel 2 is coated with a photoresist, and the stripe-shaped region where the exposure light beam is projected finally becomes a phosphor layer. Further, the stripe-shaped region where the exposure light beam does not project becomes the black light shielding layer forming portion.

FIG. 5 is a plan view of the panel 40 exposed using the shadow mask according to the comparative example and the exposure apparatus 60 shown in FIG. A black light shielding layer is formed on the panel 40. FIG. 5 shows an enlarged view of the portion B, and the stripe-shaped portion indicated by oblique lines is the black light shielding layer 42. The stripe portions 41 between the black light-shielding layers 42 are later applied with phosphors of respective colors to become phosphor layers.

  The shadow mask according to the comparative example used in the exposure of the panel 40 is the same as the shadow mask according to the present embodiment in that the auxiliary mask is superimposed on the mask body, but the shadow mask according to the comparative example is The difference is that the transmittance distribution in the horizontal direction of the screen of the light beam of the mask body alone without the auxiliary mask is continuous. The transmittance distribution of the mask main body according to this comparative example is the same as the broken line graph shown in FIG.

  For this reason, in the shadow mask according to the comparative example, in the state where the auxiliary mask is superimposed on the mask body, the amount of transmitted light is transmitted through the mask body that does not overlap with the auxiliary mask due to scattering of light within the aperture of the auxiliary mask. It is different from the amount of light. For this reason, a discontinuous portion occurs in the transmitted light amount distribution at the boundary between the portion overlapping with the auxiliary mask and the portion not overlapping with the auxiliary mask.

  In the enlarged view of FIG. 5, a boundary line 50 is a boundary line between an auxiliary mask region 51 that overlaps with the auxiliary mask and a mask body region 52 that does not overlap with the auxiliary mask. In the panel 40 facing the region 51 overlapping with the auxiliary mask, the amount of ultraviolet rays is insufficient. As a result, the width Ss of the stripe-shaped portion 41 at the portion facing the auxiliary mask with respect to the boundary line 50 is formed to be smaller than necessary than the width Sm of the portion of the stripe-shaped portion 41 not overlapping with the auxiliary mask. It will be. As described above, when the width of the stripe-shaped portion 41 on which the phosphor film is formed has a magnitude relationship, a light and dark pattern in which the auxiliary mask area 51 becomes darker than the mask main body area 52 occurs when the entire phosphor screen is viewed. To do.

  FIG. 6 is a cross-sectional view of the shadow mask 8 according to the present embodiment in the horizontal direction (X-axis direction in FIG. 2). FIG. 6 shows the cross-sectional shape of the opening in the vicinity of the boundary line 50 between the auxiliary mask region 30 with the auxiliary mask 15 and the mask body region 31 without the auxiliary mask 15. In the mask body region 31, the opening 7 of the mask body 14 is etched on the upper side (phosphor screen 5 side) with the matching point 23 as a boundary and on the lower side (electron gun 12 side). The small holes 22 are formed. The stripe width of the black light shielding layer is substantially determined by the dimension D1 between the matching points 23, which is the minimum width of the aperture cross section.

  In the auxiliary mask region 30, the dimension D2 between the matching points 23 of the opening 7 (solid line portion) of the mask body 14 is larger than the dimension D1 between the matching points 23 of the opening 7 (broken line portion) in the mask body region 31. Thus, the above-described problem of bright and dark pattern formation is solved. More specifically, in the mask main body region 31, the dimension between the matching points 23 continuously decreases from the end toward the center in the horizontal direction of the screen and becomes D1. In the auxiliary mask region 30, the dimension between the matching points 23 is once D2 and larger than D1. The dimension between the matching points 23 that has become D2 continuously decreases again toward the center.

  Here, it is preferable that the opening 27 of the auxiliary mask 15 overlaid on the mask body 14 is larger than the opening 7 of the mask body 14 in the overlapping portion.

  FIG. 7 is a graph showing the relationship between the position of the mask body in the X direction (horizontal axis) and the amount of transmitted light (vertical axis). In FIG. 7, a line 28 indicated by a solid line is based on the shadow mask according to the example, and a line 29 indicated by a broken line is based on the shadow mask according to the comparative example. In both the examples and the comparative examples, the mask body alone without the auxiliary mask was used for the measurement of the transmitted light amount.

As shown in FIG. 6, the shadow mask according to the embodiment is in the mask main body region 31.
The dimension between the coincidence points 23 continuously reduced to D1 is once increased to D2 (D2> D1) in the auxiliary mask region 30. In this case, the dimension between the matching points 23 once increased to D2 continuously decreases again toward the center.

  In the shadow mask according to the comparative example, the dimension between the coincidence points 23 continuously reduced to D1 in the mask main body region 31 is continuously reduced in the auxiliary mask region 30 as well.

  In the mask body region 31, the shadow masks according to the example and the shadow mask according to the comparative example have the same dimensions between the matching points 23 of the openings 7. Therefore, in the mask body region 31 of FIG. Line 28 and line 29 overlap. In the shadow mask according to the comparative example, even in the auxiliary mask region 30, the dimension between the matching points 23 of the opening 7 is continuously reduced. Therefore, the amount of transmitted light from the mask body region 31 to the auxiliary mask region 30 is linear. As shown by 29, it changes continuously.

  On the other hand, in the shadow mask according to the example, the dimension between the matching points 23 in the auxiliary mask region 30 is as large as D2. For this reason, the transmitted light amount does not continuously change from the mask main body region 31 to the auxiliary mask region 30, and the transmitted light amount once rises at the boundary portion between the mask main body region 31 and the auxiliary mask region 30. In the auxiliary mask region 30, the amount of transmitted light continuously changes. However, since the size between the matching points 23 is larger than that in the comparative example, the amount of transmitted light indicated by the line 28 is larger than that in the line 29 according to the comparative example. It has become. That is, in the embodiment, a discontinuous distribution in which the transmitted light amount once increases between the mask main body region 31 and the auxiliary mask region 30 can be formed, and the exposure light amount in the auxiliary mask region 30 can be increased.

  Next, the graph of FIG. 7 is based on a mask body alone without an auxiliary mask, but when the auxiliary mask is fixed, the amount of transmitted light in the auxiliary mask region 30 is reduced in both the example and the comparative example. However, in the embodiment, since the amount of transmitted light in the auxiliary mask region 30 is increased in the state of the mask body alone, the amount of transmitted light is larger than that in the comparative example even after the auxiliary mask is fixed. That is, if the amount of transmitted light corresponding to the decrease in the amount of transmitted light due to the auxiliary mask fixing is increased in the state of the mask body alone, the necessary amount of transmitted light can be secured in the auxiliary mask fixed state. The amount of transmitted light lost when passing through the mask can be compensated.

  The exposure light quantity may be increased by increasing only the horizontal opening width of the coincidence point 23 of the opening 7, but the entire opening width of the opening 7 is increased to increase the transmitted light area. Also good. For example, in the example of FIG. 6, in the auxiliary mask region 30, the width between the matching points 23 is larger than that in the mask main body region 31, but the widths of the large holes and the small holes are also increased. .

  In order to confirm the effect of the present embodiment, a comparative experiment was conducted using an 86 cm type (36 type) color picture tube. In both the comparative example and the example, the thickness of the mask main body and the auxiliary mask was 0.18 mm, and the aperture pitch was about 0.45 mm at the center. In the comparative example, the aperture width of the mask body was a size distribution that changed continuously in the horizontal direction of the screen. In contrast, in the example, the opening width of the mask body facing the auxiliary mask was increased by about 1% compared to the comparative example. For example, in the example of FIG. 6, the portion where the opening width is 0.098 mm in the comparative example is 0, 099 mm in the example. According to the comparative experiment, it was confirmed that the light and dark pattern generated in the comparative example could be eliminated in the example.

It was also confirmed that the appropriate value of the opening width of the mask body facing the auxiliary mask varies depending on the horizontal opening width of the auxiliary mask. According to this, with the auxiliary mask as a boundary, the width of the opening of the mask main body is set in the range of 1.05 times or more and 1.2 times or less of the portion where the auxiliary mask adheres to the portion where the auxiliary mask does not adhere Was confirmed to be desirable. That is, the appropriate value of the opening width is influenced by the opening width in the horizontal direction of the auxiliary mask, but if it is in the above range, it is effective for preventing the occurrence of a light / dark pattern.

  Further, the horizontal opening width of the mask body is at least 1.05 times and 1.2 times the area where the auxiliary mask is closely adjacent to the area where the auxiliary mask is not closely adjacent to the boundary where the auxiliary mask is closely attached. It was confirmed that the setting was effective within the following range. Even in this case, the opening width is set so that the amount of transmitted light continuously changes as shown by the line 28 in the region 30 in FIG. It has not changed. The above conditions are appropriately designed depending on the size of the mask opening and the thickness of the mask material.

  According to the present embodiment, the exposure light quantity that has passed through the shadow mask 8 forms a continuous light quantity distribution, the stripe width of the black light shielding layer is a continuous size distribution, the light and dark pattern of the black light shielding layer is eliminated, and the quality is high. It becomes possible to provide quality.

  According to the color picture tube of the present invention, it is possible to prevent the occurrence of bright and dark patterns on the phosphor screen while maintaining the vibration preventing effect of the auxiliary mask. Therefore, the present invention is used for, for example, a television receiver and a computer display. This is useful for a shadow mask type cathode ray tube.

1 is a cross-sectional view of a color picture tube according to an embodiment of the present invention. The perspective view of the shadow mask 8 shown in FIG. (A) is sectional drawing of the X-axis direction of the shadow mask shown in FIG. 2, (b) is sectional drawing of the Y-axis direction. Schematic of an example of an exposure apparatus. The top view of the panel formed using the shadow mask which concerns on a comparative example. Sectional drawing of the X-axis direction of the shadow mask which concerns on one embodiment of this invention. The graph which showed the relationship between the horizontal direction position (horizontal axis) and transmitted light amount (vertical axis) of a mask main body in an Example and a comparative example.

Explanation of symbols

2 Panel 5 Phosphor screen 7 Opening of mask body 8 Shadow mask 14 Mask body 15 Auxiliary mask 21 Large hole on mask screen side 22 Small hole on mask electron gun side 23 Matching point of 21 and 22 (opening)
27 Auxiliary mask opening 51 Auxiliary mask region of stripe-shaped black light-shielding layer 50 Boundary of stripe-shaped black light-shielding layer opposite to presence / absence of auxiliary mask

Claims (5)

A phosphor screen;
A shadow mask disposed opposite to the phosphor screen and having an electron beam passage hole formed thereon,
The shadow mask has an auxiliary mask fixed so as to overlap a part of the mask body, and the position of the electron beam passage hole of the mask body corresponds to the position of the electron beam passage hole of the auxiliary mask. ,
When the transmittance distribution of the electron beam of the mask main body alone toward the phosphor screen is seen in the horizontal direction of the screen, there is no difference between the portion where the auxiliary mask is fixed and the boundary portion between the portion where the auxiliary mask is not fixed. It ’s continuous,
In the discontinuous portion, the color picture tube having a decreasing transmittance as it goes from both ends of the shadow mask toward the center is once increased.   Among the portions adjacent to the boundary portion of the mask body, the opening width in the horizontal direction of the screen of the mask body in the portion where the auxiliary mask is fixed is the horizontal screen width of the mask body in the portion where the auxiliary mask is not fixed. 2. A color picture tube according to claim 1, wherein the color picture tube is larger than the opening width in the direction.   Among the portions adjacent to the boundary portion of the mask body, the opening width in the horizontal direction of the screen of the mask body in the portion where the auxiliary mask is fixed is the horizontal screen width of the mask body in the portion where the auxiliary mask is not fixed. 2. The color picture tube according to claim 1, wherein the color picture tube is 1.05 times or more and 1.2 times or less than the opening width in the direction. A phosphor screen;
A shadow mask disposed opposite to the phosphor screen and having an electron beam passage hole formed thereon,
The shadow mask has an auxiliary mask fixed so as to overlap a part of the mask body, and the position of the electron beam passage hole of the mask body corresponds to the position of the electron beam passage hole of the auxiliary mask. And
An opening in the horizontal direction of the screen of the mask body at a portion where the auxiliary mask is fixed among portions adjacent to a boundary portion between the portion where the auxiliary mask is fixed and the portion where the auxiliary mask is not fixed. A color picture tube characterized in that the width is larger than the opening width in the horizontal direction of the screen of the mask main body at a portion where the auxiliary mask is not fixed.   The opening width in the horizontal direction of the screen of the mask body in the portion where the auxiliary mask is fixed is 1.05 times or more compared to the opening width in the horizontal direction of the screen of the mask body in the portion where the auxiliary mask is not fixed. The color picture tube according to claim 4, which is 2 times or less.

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