JP3082601B2 - Shadow mask type color cathode ray tube - 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 type color cathode ray tube, and more particularly to a shadow mask in which a slot width of a peripheral portion of a perforated portion of a mask, particularly a corner portion, is prevented from being increased when a slot type shadow mask is pressed. The present invention relates to a type color cathode ray tube.

[0002]

2. Description of the Related Art As shown in FIG. 2, a shadow mask type color cathode ray tube is provided on an inner surface of a panel 1 on which an image is displayed in a direction perpendicular to a scanning line of an electron beam emitted from an electron gun 2. A phosphor film 3 having a large number of vertically continuous three-color phosphor stripes arranged thereon is formed thereon. And
A substantially conical funnel 5 having a tubular neck 4 is connected to the panel 1 to form a vacuum vessel. Also,
Three electron guns 2 are mounted in the neck portion 4 in-line, and a deflection yoke 6 for deflecting the electron beam is mounted on the outer periphery of the funnel 5. The electron beam is directed to the fluorescent film 3 on the inner surface of the panel 1. A shadow mask 8 having a slot 7 for selective transmission is mounted. In the shadow mask type color cathode ray tube having the above-described configuration, three electron beams emitted from the electron gun 2 are deflected by the horizontal deflection magnetic field and the vertical deflection magnetic field formed by the deflection yoke 6, and are spread over the entire fluorescent surface of the fluorescent film 3. Is scanned over the slot 7 of the shadow mask 8
, And collides with phosphors of the corresponding colors to excite the phosphors to emit light, thereby displaying a color image.

Here, as disclosed in Japanese Patent Laid-Open Publication No. Hei 2-103847, a normal shadow mask 8 is formed as shown in FIG.
As shown in FIG. 5, rectangular slots 7 are arranged in the masked perforated portion 8a in a mosaic pattern by arranging a large number of slot rows arranged at a constant pitch Pv in the vertical direction of the screen in a regular and horizontal manner. ing. Bridge portions 9 are formed between the slots 7 in the vertical direction to maintain the mechanical strength of the shadow mask. In addition, each slot 7
The vertical opening dimensions are all constant, and each slot row is arranged such that the position of the bridge portion 9 of the adjacent slot row bisects the other slot 7 in the vertical direction. Also, since the bridge portion 9 is a non-transmissive portion of the electron beam, it generates a shadow portion on the display screen.
As the focus characteristics of the electron beam are improved and the beam spot diameter is reduced, the difference in brightness and darkness on the display screen becomes large, and the influence of moire fringes becomes significant. Therefore, the bridge width has to be reduced as much as possible.

[0004]

However, if the bridge width is designed to be the minimum width that maintains the mechanical strength of the shadow mask 8, the shadow mask 8 is formed into a convex spherical surface corresponding to the inner spherical surface of the panel 1. When formed by pressing, there is a problem that the bridge portion 9 in the peripheral portion of the hole with the mask extends and the slot width increases.

[0005] An object of the present invention is to solve the above-mentioned problems by changing the bridge width between the central portion and the peripheral portion of the perforated portion of the shadow mask, and increasing the bridge width at the peripheral portion. Another object of the present invention is to provide a color cathode ray tube having a shadow mask having a uniform slot width without deteriorating the screen display characteristics.

[0006]

According to the present invention, there are provided three electron guns in an in-line arrangement, and slots elongated vertically in a direction perpendicular to a scanning line of an electron beam spot from these electron guns are fixed through a bridge portion. A shadow mask type color comprising a shadow mask in which a row of slots connected at a pitch (Pv) are arranged in a horizontal direction, and a stripe-shaped fluorescent screen which is disposed opposite to the shadow mask and is continuous in a vertical direction. In a cathode ray tube, a shadow mask type color cathode ray tube characterized in that a bridge width of a slot at a peripheral portion of the shadow mask is larger than a bridge width of a slot at a central portion. Further, the bridge width of the peripheral slot is reduced by a fixed amount for each row as going from the outermost end to the center, and the bridge width of the slot is changed within a range of 10 mm or less from the outermost end. Desirably.

[0007]

According to the above structure, when the shadow mask is press-molded, the bridge width of the peripheral portion, which is the boundary portion of the perforated portion of the shadow mask where stress concentration occurs most, can be increased to improve the mechanical strength. In addition, since the spot diameter of the electron beam is large in the peripheral portion where the deflection amount is large, the difference in brightness of the screen due to the increase in the bridge width in the peripheral portion is reduced, so that the screen display characteristics are not deteriorated. By reducing the bridge width of the peripheral slot from the outermost end to the center by a fixed amount for each row, stress can be dispersed, so stress concentration can be reduced and the peripheral slot width can be increased. Can be prevented. Further, as a result of experimental confirmation, the range in which the slot width is increased was within 10 mm from the outermost end even for a 15-inch type or larger color cathode ray tube.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The same parts as those in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 1, a shadow mask 10 made of an Invar alloy having a thickness of 0.05 mm to 0.13 mm of a 15-inch color cathode ray tube of one embodiment of the color cathode ray tube of the present invention has a rectangular shape in a mask hole 10a. Is a constant pitch Pv = 1.0 mm in the vertical direction of the screen, and the bridge width Bw of the central bridge 9 is 0.1 mm.
Are arranged in a mosaic manner by regularly arranging a large number of slot rows arranged substantially in parallel in the horizontal direction. Each slot row is arranged such that the position of the bridge portion 9 of the adjacent slot row bisects the other slot 7 in the vertical direction.

A bridge portion 9S1 having a bridge width of 0.14 mm is formed between the slots 7S1 in the vertical direction of the outermost end slot row, and the bridge width is 0.136 mm toward the center portion. , 0.132mm
And is reduced by a constant amount. Similarly, between each of the slots 7S2 in the vertical direction of the slot row adjacent to the outermost end slot 7S1, a bridge section 9 having a bridge width of 0.138 mm in the outer end slot is similarly provided.
S2 is formed, and the bridge width 9S2 is 0.134 mm, 0.130 mm as going from the peripheral part to the central part.
And is reduced by a constant amount. Further, the bridge width between the slots 7S3 of the slot row adjacent to the slot 7S2 is reduced by a constant amount such that the bridge width Bw of the central slot is 0.136 mm for each slot row until the same dimension as the bridge width Bw = 0.1 mm. It is formed.

According to this embodiment, since the bridge width of the slot in the peripheral portion of the perforated portion of the mask is formed so as to be gradually larger than the bridge width of the slot in the central portion, the press-forming of the shadow mask is difficult. Since the mechanical strength of the peripheral portion is increased and the stress can be dispersed, the expansion of the slot width in the peripheral portion can be prevented, and a shadow mask having a uniform slot width over the entire screen can be provided. In addition, it has been confirmed that since the spot diameter of the electron beam is large in the peripheral portion where the amount of deflection is large, the difference in brightness of the screen is reduced by increasing the bridge width in the peripheral portion, so that the screen display characteristics are not degraded. Further, as a result of experimental confirmation, even in a shadow mask of a 21-inch color cathode ray tube, the range in which the slot width increases during press molding is limited to a range of 10 mm from the peripheral portion toward the center portion. Therefore, it is sufficient that the above-mentioned change region of the slot width is within 10 mm from the outermost slot.

Although the example of the shadow mask of the 15-inch color cathode ray tube has been described above, the present invention is not limited to the above example, and the bridge width is determined by the material, plate thickness, slot pitch, opening size, etc. of the shadow mask. It goes without saying that the magnification can be designed to an optimum value.

[0012]

As described above, according to the color cathode ray tube of the present invention, when the shadow mask is press-molded, the bridge width of the peripheral portion, which is the boundary portion of the mask hole where the stress is most concentrated, is enlarged. As a result, the mechanical strength can be improved. In addition, since the spot diameter of the electron beam also increases in the peripheral portion where the deflection amount is large, the difference in brightness of the screen due to the increase in the bridge width in the peripheral portion is reduced, so that the deterioration of the screen display characteristics can be prevented. By reducing the bridge width of the peripheral slot from the outermost end to the center by a fixed amount for each row, stress can be dispersed, so stress concentration can be reduced and the peripheral slot width can be increased. Can be prevented. If the bridge width of the slot within 10 mm from the outermost end is larger than the bridge width of the center slot, the slot width does not increase when the shadow mask is formed.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a shadow mask of a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a color cathode ray tube.

FIG. 3 is a plan view of a main part of a shadow mask of a conventional color cathode ray tube.

[Explanation of symbols]

 2 Electron gun 3 Fluorescent film (fluorescent screen) 7 Slot 9 Bridge part 9S1, 9S2 Bridge part of peripheral slot 10 Shadow mask 10a Mask hole part Pv Slot pitch Bw Bridge width

Claims (1)

(57) [Claims] 1. An in-line arrangement of three electron guns, and a slot row in which slots vertically elongated in a direction perpendicular to scanning lines of electron beam spots from these electron guns are arranged at a constant pitch via a bridge section. A shadow mask type color cathode ray tube comprising: a shadow mask having a mask hole portion arranged side by side in a direction, and a stripe-shaped fluorescent screen which is disposed to face the shadow mask and is continuous in a vertical direction. The bridge width of the peripheral slot of the masked hole portion of the shadow mask is made larger than the bridge width of the central slot, and the center of the mask holed portion is formed from the outermost peripheral portion to the center.
The peripheral slot within 10 mm
The width of the edge has been reduced from the outermost part of the mask hole to the center.
Accordingly , a shadow mask type color cathode ray tube characterized in that the amount is reduced by a certain amount for each column .