JPH0765738A - Color picture tube - Google Patents

Abstract

PURPOSE:To allow only a desired electron beam to pass through an opening by forming an angle formed by a straight line along a ridge line from an opening end on an electron gun side toward the thickness direction of a shadow mask and the axis of an opening larger than a specific angle. CONSTITUTION:An angle alpha formed by a straight line 35 along a ridge line from a small hole end 321 toward a ridge line mating portion 34 and the axis 36 of an opening is set larger than an angle gamma formed by a straight line 38 connecting a large hole end 311 to a contact point 39 near the mating portion 34 and the axis 36 of the opening. An electron beam 33 passing from a small hole 32 side of the opening toward the large hole 31 side reaches a fluorescent screen 42 without collision against a side wall of the opening, and further, a passing quantity can be secured. A diameter of the beam 33 passing through the electron beam opening is substantially identical to the dimension of the small hole of the opening. Consequently, control of the dimension of the opening of the beam 33 allows the diameter of the beam 33 reaching the fluorescent screen 42 to be controlled. Even if a reflection electron beam is generated inside the opening, it cannot reach the fluorescent screen 42, thus obtaining a screen of high quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask type color picture tube, and more particularly to the shape of electron beam apertures in the shadow mask.

[0002]

2. Description of the Related Art As shown in FIG. 4, a shadow mask type color picture tube has an envelope made of glass, which has a substantially rectangular face plate portion 411, a skirt portion 412 connected thereto, and a face plate portion. A cylindrical neck portion 414, which is arranged to face 411, a skirt portion 412, and a neck portion 414.
And a funnel portion 413 that connects the two. A phosphor screen 42 in which phosphors that emit red, blue and green are regularly arranged is formed on the inner surface of the face plate portion 411, while red, blue and green are formed in the neck portion 414. An electron gun 45 for emitting a plurality of corresponding electron beams 45G, 45R and 45B is arranged. Further, a shadow mask 43 having a large number of electron beam apertures 431 regularly arranged so as to closely face and face the fluorescent screen 42 at a predetermined interval is provided. The shadow mask 43 is joined to the mask frame 432, and is fixed to the stud pin 434 of the skirt portion 412 via the mask holder 433. The cross-sectional shape of the electron beam aperture 431 of the shadow mask 43 is the phosphor screen.
The surface opening on the 42 side (hereinafter referred to as a large hole) is formed larger than the surface opening on the electron gun 45 side (hereinafter referred to as a small hole), and the electron beam is obliquely inclined toward the periphery of the shadow mask. A certain amount of electron beam at the time of incidence is secured (not shown).

In a color picture tube having such a structure,
The three electron beams 45G, 45R and 45B emitted from the electron gun 45 are controlled and accelerated, and proceed toward the fluorescent screen 42 while being deflected by the magnetic field of the deflecting device 46 disposed outside the funnel portion 413. To do. Then, the three electron beams are controlled so as to be concentrated in one electron beam opening 431 of the shadow mask 43, and are dispersed again in the distance from here to the phosphor screen, and are correctly projected to the corresponding phosphors. And display a color image.

As described above, the shadow mask of the color picture tube uses the principle of parallax so as to correctly project only the phosphors of each color having a one-to-one relationship with the aperture of the electron beam geometrically. It has an electron beam passing function and is an important component called a color selection electrode.

Circular and rectangular holes are used for the electron beam aperture of this shadow mask. The long side of the substantially rectangular electron beam aperture is composed of a number of vertical arrays that are substantially parallel to the short side (vertical axis) of the substantially rectangular face plate. The adjacent short side of the electron beam aperture is the long side of the face plate (horizontal axis).
S Substantially parallel bridges are arranged.
In the shadow mask having such a rectangular electron beam aperture, the width of the bridge portion in the vertical direction is set as small as possible, and the tensile strength in the horizontal axis direction is larger than the tensile strength in the vertical direction. It is considered as a structure.

Of these electron beam apertures, circular ones are used for display tubes for displaying characters and figures with high precision, and rectangular ones are used for consumer tubes used for televisions. . Further, as a recent trend, there is a remarkable demand for display tubes as terminals for personal computers, office computers, and EWS, while consumer tubes, including those for high-definition broadcasting, are becoming larger in size.

In any case, what is different from the conventional method is that an image with less external light reflection and less distortion is required from the viewpoint of ergonomics. For this reason, a flat square tube having a flatter screen is indispensable.
Along with this, the shadow mask having a relative relationship with the phosphor screen also needs to be flattened, that is, have a large radius of curvature.

Therefore, in a more flattened shadow mask, the angle of incidence of the electron beam on the shadow mask inevitably becomes large as compared with the conventional shadow mask.
Especially in the peripheral area. As a result, as compared with the conventional shadow mask, a part of the incident electron beam is more likely to hit the hole edge or hole wall of the electron beam aperture, and the electron beam shape is distorted, so-called beam chipping occurs. , Reduce brightness and white uniformity. In addition, the electron beam that strikes and reflects the hole edge or hole wall of the electron beam aperture causes the unintended phosphor to emit light, resulting in a reduction in contrast.

Such a problem is more likely to occur as the plate thickness of the shadow mask material is thicker and the pitch of the electron beam apertures is smaller for high resolution. However,
Even if the tube has the same size and pitch as the conventional tube, it becomes apparent as the incident angle to the electron beam aperture increases like a flat square tube, and the quality of the color picture tube deteriorates.

[0010]

As a means for solving these problems, Japanese Laid-Open Patent Publication Nos. 50-142160 and 57-57449 disclose a shadow mask having a rectangular electron beam aperture. In the publication, as shown in FIG. 5 (A), the direction in which the electron beam 53 passes through the center of the large hole 51 on the phosphor screen side with respect to the center of the small hole 52 on the electron gun side of the shadow mask. A so-called off-center mask that has been shifted is proposed.

By using such an off-center mask, the incident electron beam can be transmitted through the side wall of the aperture and the end 511 of the large aperture.
The risk of hitting the beam and causing a beam drop is avoided. However, as shown in FIG. 5A, the beam passing amount of the electron beam aperture, that is, the width of the passing electron beam is as shown in FIG. 5A, the left side of the incident electron beam is the small hole end 521 on the left side of the small hole 52 on the electron beam incident side. Depends on. On the other hand, the right side of the incident electron beam is determined by the straight line 53 along the ridgeline of the large hole 51 and the small hole 52 of the opening. That is, a ridge line matching portion within the plate thickness that matches the ridge line from the large hole end 511 on the large hole 51 side toward the thickness direction of the shadow mask and the ridge line from the small hole end 521 of the small hole 52 toward the shadow mask plate thickness direction within the plate thickness. Although it has 54, it is determined by the large hole end 511 on the right side of the large hole 51 side and the straight line which is in contact with the contact point 59 in the vicinity of the ridge line matching portion 54. Therefore, the width of the actual passing electron beam is smaller than the aperture diameter of the small hole 52.

Further, if the position of the ridge matching portion 54, that is, the distance from the surface of the shadow mask on the small hole 52 side to the ridge matching portion 54 changes, the width of the passing electron beam also changes,
In a color picture tube with a small electron beam landing margin on the phosphor screen, white uniformity is reduced. Further, in a flat square tube having an incident angle of the electron beam larger than that of the conventional tube, as shown in FIG. 5B, the electron beam is applied to the ridgeline 541 from the small hole end 521 of the small hole 52 to the ridgeline matching portion 54. The rate at which 53 hits and reflects increases. Since the reflected electron beam 531 is not controlled at all, it causes a fluorescent substance other than a predetermined fluorescent substance to be emitted to emit light, which lowers the black level of the entire screen and significantly reduces the contrast. As a result, the situation is the same as when viewed under daylight, and the image quality as a color television is degraded.
Note that FIG. 5 shows the cross-sectional aperture shape of the electron beam aperture along the horizontal axis direction of the shadow mask.

As described above, in order to prevent the electron beam from striking the side wall of the electron beam aperture and the large hole end 511 to cause beam chipping, the aperture centers of the large hole and the small hole are adjusted according to the required amount. Even if the shadow mask is shifted in the horizontal direction and the vertical direction, it is inevitable to generate an unwanted reflected electron beam in a color picture tube in which the shadow mask is flatter and the incident angle of the electron beam is large. The reflected electron beam reflected on the phosphor screen side also causes unnecessary phosphor parts to emit light, resulting in worsening of black spots on the phosphor screen and deterioration of contrast.

The present invention has been made in view of the above problems. Only a desired electron beam is allowed to pass through an electron beam aperture without causing electron beam chipping, and the electron beam is projected onto the side wall of the aperture. It is an object of the present invention to provide a color picture tube in which a reflected electron beam does not cause unnecessary phosphors to emit light even when reflected.

[0015]

According to the present invention, a phosphor screen formed on the inner surface of a substantially rectangular face plate,
An electron gun arranged to face the fluorescent screen, and a plurality of substantially rectangular electron beam apertures arranged between the fluorescent screen and the electron gun and closely arranged to face the fluorescent screen and arranged regularly. And a long side of the substantially rectangular electron beam aperture is disposed substantially parallel to a short side of the substantially rectangular face plate, and a short side adjacent to the electron beam aperture. A color picture tube having at least sides arranged vertically through a bridge portion, and a hole on the side of the fluorescent screen of the electron beam hole having a shadow mask having a larger area than the hole on the side of the electron gun. In, in the plate thickness direction and the ridge line from the aperture end of the shadow mask toward the plate thickness direction of the shadow mask in the plate thickness direction of the shadow mask in the plate thickness direction of the shadow mask It has ridge line mating parts that match The angle formed by the center axis of the opening and the straight line drawn along the ridge line extending in the plate thickness direction of the shadow mask from the hole end on the electron gun side is defined by the incidence trajectory of the electron beam and the center axis of the opening. A color picture tube that is larger than the angle formed, and a ridge line along the plate thickness direction of the shadow mask from the aperture end on the phosphor screen side of the shadow mask is from the aperture end on the electron gun side of the shadow mask. A straight line that has a ridge line matching portion that matches the ridge line along the plate thickness direction within the plate thickness, and is drawn along the ridge line facing the plate thickness direction of the shadow mask from the hole end on the electron gun side and the center of the opening An angle formed by the axis is larger than an angle formed by the central axis of the opening and a straight line connecting the aperture end on the phosphor screen side and the vicinity of the ridge line matching portion, and further, the electron gun side. From the open end of the The straight line drawn along the ridge line facing the plate thickness direction of the black and the intersection of the straight line connecting the aperture end on the phosphor screen side and the vicinity of the ridge line matching portion is the electron with respect to the plate thickness of the shadow mask. 1/3 from the gun side surface
A color picture tube within, or a contact point near the ridge matching portion of a straight line connecting the opening end on the phosphor screen side and the vicinity of the ridge matching portion is the shadow from the opening end on the electron gun side. A collar located closer to the aperture end on the electron gun side than an intersection of a straight line drawn along a ridge line facing the plate thickness direction of the mask and a straight line connecting the aperture end on the phosphor screen side and the vicinity of the ridge line matching portion. It is a picture tube.

[0016]

In order to prevent the electron beam incident on the entire surface of the shadow mask from being undesirably shattered (broken) at the electron beam aperture and preventing the reflected electron beam from reaching the fluorescent screen. , It suffices to cut the electron beam by a line instead of a plane. In other words, in the cross section of the opening on the side where the electron beam passes, the electron beam is cut at the ridge line matching part where the ridge lines facing from the large hole and the small hole in the plate thickness direction match, and the ridge line from the small hole end to the ridge line matching part. The aperture wall formed by is configured such that the angle formed by the line along the ridgeline and the central axis of the aperture is larger than the angle formed by the incident beam of the electron beam and the central axis of the aperture. There is. Further, the inclination along the ridgeline may be such that the reflected electron beam does not reach the fluorescent screen even if the reflected electron beam is generated by the electron beam impingement.

Further, a line along the ridgeline of the cross section of the hole, that is, a straight line connecting the end of the large hole and the contact point near the ridge line coincides with the central axis of the hole, and the angle of incidence of the electron beam. It is configured to be larger than the angle formed by the central axis of the opening.

With this structure, the electron beam passing through the electron beam aperture will not be chipped, and the electron beam will hit the side wall of the aperture to generate a reflected electron beam. Even if a reflected electron beam is generated, it is possible to prevent the reflected electron beam from reaching the phosphor screen.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The configuration of the color picture tube in this embodiment is the same as that of the conventional color picture tube except the electron beam aperture of the shadow mask, and the description of the overall construction of the color picture tube is omitted. This will be described below. FIG. 1 shows the sectional shape of the electron beam aperture in the central portion of the shadow mask of this embodiment, and FIG. 2 shows the sectional shape of the electron beam aperture in the peripheral portion of the shadow mask. 1 and 2, the left side shows the sectional aperture shape of the electron beam aperture along the horizontal axis direction of the shadow mask, and the right side shows the bridge of adjacent electron beam apertures along the vertical axis direction of the shadow mask. The cross-sectional shape of each part is shown.

The electron beam apertures of the shadow mask shown in FIG. 1 are formed in a thin metal plate having a thickness of 0.13 mm at a hole pitch of 0.3 mm pitch, and the large holes 11 on the phosphor screen side have a diameter of 0.28 mm. The electron gun side small hole 12 is formed to have a diameter of 0.14 mm. At the electron beam aperture in the center of the shadow mask, the passing electron beam 13 is of course substantially perpendicular to the shadow mask plane.

On the other hand, FIG. 2 shows the state of electron beam apertures in the peripheral portion of the shadow mask. The shape of the small hole 22 side substantially determines the width through which the electron beam 23 escapes, but the difference between the small hole end 221 and the large hole end 211 is that the electron beam 22 on the right side of the center line in the drawing is inclined. Let Δ1 be the direction of the large hole 21 side that exits through, and Δ2 be the direction of the small hole 22 side where the electron beam 22 on the left side of the center line inclines and is incident. In the vicinity of the center of the shadow mask, as shown in FIG.
Although Δ1 is equal to Δ2, Δ1 is configured to be larger than Δ2 in the peripheral portion of the shadow mask as shown in FIG. 2B. On the other hand, in the bridge direction, the central axis on the large hole 21 side and the central axis on the small hole 22 side are not on the same axis, but are deviated by Δb.

Further, as shown in FIG.
Ridge line from the large hole end 311 in the plate thickness direction to the small hole end 32 of the small hole 32
The ridgeline from 1 is matched at the ridgeline matching portion 34, and the angle α formed by the straight line 35 along the ridgeline from the small hole end 321 to the ridgeline matching portion 34 and the central axis 36 of the aperture is the same as the incident trajectory of the electron beam 33. It is configured to be larger than the angle β formed with the central axis 36 of the opening. Further, as shown in FIG. 3B, the angle α formed by the straight line 35 along the ridge line from the small hole end 321 to the ridge line matching portion 34 and the central axis 36 of the opening is equal to the large hole end 311 and the ridge line matching portion. The angle γ formed by the straight line 38 connecting the contact point 39 near 34 and the central axis 36 of the aperture is larger than the angle γ.

With such a structure, the electron beam that enters from the small hole side of the opening and escapes to the large hole side reaches the fluorescent screen without hitting the side wall of the opening, and the amount of passage therethrough. Reserved. That is, since the electron beam diameter passing through the electron beam aperture is substantially the same as the small hole size of the aperture, controlling the aperture size of the electron beam also controls the electron beam diameter reaching the phosphor screen. It becomes possible. Further, even if the electron beam 33 strikes the ridge, the reflected beam does not reach the phosphor screen.

Further, as shown in FIG. 3, a straight line 35 extending from the small hole end 321 to the ridge line matching portion 34 and a straight line 38 connecting the large hole end 311 and the contact point 39 near the ridge line matching portion 34. The distance t from the intersection 37 to the surface of the small hole 32 side is preferably large from the viewpoint of shadow mask strength. Further, the position of the contact point 39 of the straight line 38 connecting the large hole end 311 and the contact point 39 in the vicinity of the ridge line matching portion 34 should be closer to the surface of the small hole 32 side than the above t.

However, from the viewpoint of forming holes by etching, it is necessary to increase the etching amount from the small hole 32 side in order to increase t. When the etching amount is increased, the side etching amount is inevitably increased. Therefore, the size of the pattern to be baked must be reduced by that amount, which causes uneven pattern quality. Further, in order to increase the etching amount of the small holes, it is necessary to increase the amount of etching liquid supplied to the small holes. Normally, the small hole side is located above the mask material that is conveyed horizontally, but even if the spray nozzle is oscillated and the etching solution on the mask material and the contact of the solution are held evenly, the amount of solution increases as the amount of solution increases. As a result, a non-uniform liquid pool occurs, causing uneven masking. Therefore, the size of t is preferably 1/3 or less of the mask thickness from the viewpoint that uniform etching can be maintained relatively easily.

A method of manufacturing the shadow mask having the above structure will be described below. First, a mask material having a desired plate thickness is degreased and washed with an alkaline solution or the like, and then resist films are formed on both surfaces of the mask material. After that, the target large and small hole opening patterns are closely arranged on both surfaces of the mask material on which the resist film is formed, and an opening pattern latent image is formed on the resist film by an ultraviolet light source. The formation of the opening pattern is performed using, for example, a photo plotter manufactured by Gerber, Inc. in the United States.

The incident angle of the electron beam is larger in the peripheral portion than in the central portion of the mask because it is obliquely incident, but depending on the type of mask, as shown in FIG. Also, there are some things in which the alignment state of the small holes shifts toward the periphery of the mask. Further, as the opening pitch becomes smaller, the large hole diameter also becomes smaller, and the possible Δ1 also becomes smaller. Therefore, in some masks, a large shift amount must be taken. Furthermore, in some masks, the required Δ1 increases as the mask plate thickness increases, and a large shift amount must be taken. The mask opening pattern used to create these shadow masks is a small hole pattern for a large hole pattern required depending on each position of the pattern, or a large hole pattern when a large hole pattern is matched with a small hole pattern. The center axes of the comrades are misaligned. Of course,
Some masks do not require misalignment of large and small holes over the entire surface of the mask.

Then, the unexposed resist film is dissolved and removed by spraying warm water of about 40 ° C. onto the resist film,
By the subsequent etching, the mask material in the portion where the opening is to be formed is exposed. After the above development, heat treatment is performed at a temperature of about 200 ° C. to improve the etching resistance of the resist film. After that, if the mask material is mainly composed of iron, a hot ferric chloride solution is sprayed to etch the opening-corresponding portion where the resist film does not exist, and the opening having the target size and cross-sectional shape is formed. Drill holes. After the etching is completed, the resist film is removed, and the film is washed and dried to obtain a target mask.

The most important thing as an etching method for making the cross section of the opening consisting of the ridge line from the end of the large and small holes in the plate thickness direction and the ridge line matching portion where the ridge line coincides is the large and small hole side. It is to control the etching conditions from. The method will be described below.

In the first method, when etching is performed from both sides while horizontally transporting the shadow mask material in which the small holes are held up and the large holes are held down, the etching is performed by spraying the small holes through the large holes. Increase the amount of liquid or perform it under the condition that the impact force is strong. For this purpose, a spray nozzle with a large amount of liquid discharged at a constant pressure may be used on the large hole side. Alternatively, when the same spray nozzle is used for both the large hole and the small hole, the spray pressure on the large hole side may be higher than the spray pressure on the small hole side. By doing so, the etching liquid sprayed from the large hole side works to scrape off the thick portion formed by the ridge line portion and the small hole portion where the large and small holes coincide. The opening size is unlikely to increase because the eaves of the resist film generated by side etching suppresses the progress of etching. Therefore, the target opening cross-sectional shape can be obtained in a state in which the fluctuation of the opening size is reduced.

In the second method, the mask plate thickness is first applied only from the large hole side while the small hole side is protected from being exposed to the etching solution or the small hole side is covered with an etching protective film. More than half of the etching. Then, etching is performed from both sides until the desired aperture size is obtained. As the etching conditions from both sides, the conditions of the above first method may be used. According to such etching, the substantial thickness of the mask material is reduced by the first etching,
As a result, since it is equivalent to etching a thin plate, the side etching amount can be reduced because the etching time of the small holes is short. Therefore, the pattern quality is improved as much as the resist pattern size can be increased, and the side etching variation is reduced as the etching time is shortened. As a result, a shadow mask with less variation in aperture size can be obtained. On the other hand, as the etching time from the large hole becomes extremely long, the wall thickness of the portion formed by the ridge line part where the large and small holes match and the beam traveling part can be shaved off to make it thin A cross-sectional shape is obtained.

[0032]

As described above, according to the present invention, the electron beam incident on the aperture of the shadow mask does not cause beam chipping due to the collision with the side wall of the aperture, and is reflected within the aperture. Even if an electron beam is generated, it does not reach the fluorescent screen. Therefore, a color picture tube using such a shadow mask has a good black spot and can provide a high quality screen with excellent white uniformity. Also,
Since the dimensional variation of the aperture of the shadow mask is extremely small,
It is possible to obtain a color picture tube having good unevenness and improved quality of the fluorescent screen.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a shape of an electron beam aperture in a central portion of a shadow mask as one embodiment of the present invention.

2A and 2B are cross-sectional views showing the shape of electron beam apertures in the peripheral portion of a shadow mask as an embodiment of the present invention.

3 (A) and 3 (B) are cross-sectional views for explaining the state of electron beam incidence on the electron beam aperture of FIG.

FIG. 4 is a schematic cross-sectional view showing the overall configuration of a color picture tube.

5A and 5B are cross-sectional views for explaining a state of electron beam incidence on a conventional electron beam aperture corresponding to FIG.

[Explanation of symbols]

31 ... Large hole, 32 ... Small hole, 33 ... Electron beam, 34 ... Ridge line matching part, 35 ... Line along ridge line, 36 ... Center axis of aperture, 37 ... Intersection point, 31
1 ... Large hole end, 321 ... Small hole end, 42 ... Fluorescent screen, 43 ... Shadow mask, 45 ... Electron gun.

Claims (4)

[Claims] 1. A fluorescent screen formed on the inner surface of a substantially rectangular face plate, an electron gun arranged to face the fluorescent screen, and between the fluorescent screen and the electron gun and close to the fluorescent screen. A plurality of substantially rectangular electron beam apertures arranged facing each other and regularly arranged, the long sides of the substantially rectangular electron beam apertures being the substantially rectangular face. The short sides adjacent to the electron beam apertures are arranged substantially parallel to the short sides of the plate, and the adjacent short sides are vertically arranged via a bridge portion, and the apertures on the phosphor screen side of the electron beam apertures are the above-mentioned. In a color picture tube having at least a shadow mask having an area larger than the aperture on the electron gun side, the ridge line extending from the aperture end on the fluorescent screen side of the shadow mask in the plate thickness direction of the shadow mask is as described above. From the hole end on the electron gun side A ridge line that matches the ridge line in the plate thickness direction of the shadow mask and a ridge line matching portion that matches within the plate thickness, and a straight line drawn along the ridge line in the plate thickness direction of the shadow mask from the hole end on the electron gun side; A color picture tube characterized in that an angle formed by a central axis of the opening is larger than an angle formed by an incident trajectory of the electron beam and a central axis of the opening. 2. A fluorescent screen formed on the inner surface of a substantially rectangular face plate, an electron gun arranged to face the fluorescent screen, and between the fluorescent screen and the electron gun and close to the fluorescent screen. A plurality of substantially rectangular electron beam apertures arranged facing each other and regularly arranged, the long sides of the substantially rectangular electron beam apertures being the substantially rectangular face. The short sides adjacent to the electron beam apertures are arranged substantially parallel to the short sides of the plate, and the adjacent short sides are vertically arranged via a bridge portion, and the apertures on the phosphor screen side of the electron beam apertures are the above-mentioned. In a color picture tube having at least a shadow mask having an area larger than the opening on the electron gun side, a ridge line extending in the plate thickness direction of the shadow mask from the opening end on the fluorescent screen side of the shadow mask is From the hole end on the electron gun side A ridge line along the plate thickness direction of the shadow mask and a ridge line matching portion that matches within the plate thickness, and a straight line drawn along the ridge line from the hole end on the electron gun side toward the plate thickness direction of the shadow mask The color picture tube characterized in that the angle formed by the central axis of the opening is larger than the angle formed by the central axis of the opening and a straight line connecting the opening end on the phosphor screen side and the vicinity of the ridge line matching portion. 3. The color picture tube according to claim 1 or 2, wherein a straight line drawn from an end of the hole on the side of the electron gun along a ridge line extending in a plate thickness direction of the shadow mask and an opening on the side of the phosphor screen. A color picture tube characterized in that an intersection of a straight line connecting the hole end and the vicinity of the ridge line matching portion is within 1/3 of the electron gun side surface with respect to the thickness of the shadow mask. 4. The color picture tube according to claim 1, wherein a contact point near the ridge line matching portion of a straight line connecting the aperture end on the phosphor screen side and the ridge line matching portion is on the electron gun side. An opening on the electron gun side of the intersection of a straight line drawn from the opening end along the ridgeline facing the thickness direction of the shadow mask and a straight line connecting the opening end on the phosphor screen side and the vicinity of the ridgeline matching portion A color picture tube characterized by being located on the edge side.