JP2002231149A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode-ray tube capable of increasing the strength of a shadow mask and preventing color purity from being deteriorated. SOLUTION: The shadow mask 12 opposed to a phosphor screen comprises a generally rectangular mask main face 20 formed by press forming in a smooth dome shape and having electron beam passing holes 19 and a skirt part 18 extended from the peripheral edge 21 of a mask effective part and bent in the direction generally orthogonal to the mask main face. A pair of notches 26 are formed at the corner parts of the skirt part to form a tongue piece part 30 at each corner part. At the skirt part, a plurality of open holes 32 for absorbing an excess wall at the skirt part at the time of press forming are formed between the extended ends of the notches and the peripheral edges of the mask main face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat mask and a shadow mask structure for a color cathode ray tube.

[0002]

2. Description of the Related Art Generally, a color cathode ray tube has a glass panel having a substantially rectangular effective portion, a glass funnel connected to this panel, and a cylindrical panel connected to a small diameter portion of the funnel. A vacuum envelope consisting of a glass neck is provided. Blue,
A phosphor screen composed of a three-color phosphor layer in the shape of a dot or stripe emitting green and red light and a black light-shielding layer is formed. Further, a shadow mask having a large number of electron beam passage holes is arranged in the vacuum envelope so as to face the phosphor screen. In the neck, an in-line type electron gun that emits three electron beams arranged in a line on the same axis is provided, and a deflection yoke is mounted from the outer periphery of the neck to the outer peripheral surface of the funnel. ing.

In the color cathode ray tube having the above structure, the three electron beams emitted from the electron gun are deflected in the horizontal and vertical directions by a horizontal and vertical deflection magnetic field generated by a deflection yoke, and the phosphor screen is irradiated with a high frequency through a shadow mask. And a vertical scan at a low frequency to display a color image. At this time, the electron beam emitted from the electron gun strikes the phosphor screen at a certain incident angle and undergoes color selection on a shadow mask according to the incident angle. Therefore, the three electron beams correspond one-to-one to each of the red, blue, and green colors of the phosphor screen.

In the above-mentioned color cathode ray tube, the shadow mask has a radius of curvature of about 500 to 80,000 mm, is formed in a gentle dome shape, and has a large number of electron beams having a diameter of about 100 μm. The mask has a substantially rectangular mask main surface having holes formed therein, and a skirt portion extending to the electron gun side substantially at right angles from the periphery of the mask main surface. The shadow mask is fixed to a mask frame via a skirt portion, and the mask frame is detachably supported by stud pins projecting from a panel via an elastic support.

[0005] Usually, the shadow mask is 0.1 to 0.2.
It is formed into a desired shape by press-forming a flat mask base material made of an Invar material (iron-nickel alloy) having a thickness of mm and having an electron beam passage hole formed in advance. The shadow mask forms a shadow mask structure by welding a tongue piece formed at each of the corners of the skirt, and at substantially the center of the long and short sides to the mask frame.

[0006]

As described above, the shadow mask is manufactured by press molding, but it is difficult to obtain a desired mask surface shape because the invar material is springy. That is, since the skirt portion of the shadow mask is bent so as to draw an arc parallel to the tube axis and along the curved surface shape of the main surface of the mask, the radius of curvature of the extended edge of the skirt portion is equal to the upper edge of the skirt portion. That is, the radius of curvature is smaller than the radius of curvature of the peripheral edge of the mask main surface. For this reason, wrinkles due to excess thickness are likely to occur at the lower edge of the mask skirt.

In order to reduce the occurrence of such wrinkles, a notch is formed in the shadow mask from the lower end of the skirt. This cut is commonly called a skirt notch. For example, by forming notches at the lower end portion and the corner portion of the mask of the shadow mask, respectively, the formability of the skirt portion and the corner portion of the shadow mask is improved, and the amount of wrinkles generated at the corner portion of the shadow mask is suppressed.

However, if a notch is deeply inserted to sufficiently reduce wrinkles, the strength of the shadow mask is reduced.
Applying the twisting force by holding the corners of the shadow mask easily distorts it into a diamond shape. This phenomenon is to prepare a square box,
It is the same phenomenon that the strength of the box is reduced when the diagonal part is cut off.

The fact that the strength of the shadow mask alone is weak means that the strength is weak even in a state where the shadow mask is assembled on the mask frame (shadow mask structure). When the strength of the shadow mask structure is insufficient, the electron beam passage hole of the shadow mask does not match the phosphor of the panel phosphor screen due to imbalance in the amount of thermal expansion of the mask frame or the like during operation of the color cathode ray tube. . As a result, the electron beam spot shaped by the shadow mask cannot completely match the phosphor screen of the target color, resulting in a decrease in color purity. Further, such imbalance shows a behavior in which the shadow mask structure is twisted, and particularly occurs as a landing diamond formation.

[0010] Further, since the manufacturing process of the color cathode ray tube includes a number of heat treatment processes, distortion occurs in the shadow mask itself due to thermal expansion of the mask frame, and the amount of deformation of the shadow mask gradually changes. For this reason, at the time of manufacturing a color cathode ray tube, the black matrix (BC) cannot be accurately aligned with the red phosphor, the green phosphor, and the blue phosphor (SC), resulting in a mismatch between BC and SC. And
When this mismatch occurs, the electron beam spot shaped by the shadow mask cannot completely match the phosphor screen of the target color, and the emission luminance of each color becomes unbalanced, resulting in a decrease in color purity. Become. This imbalance also shows a behavior in which the shadow mask structure is twisted, and often occurs as a diamond formation.

Therefore, it is important to improve the strength of the shadow mask and the shadow mask structure. In recent years, large-sized flat color cathode ray tubes of high definition and high brightness have been manufactured, and even a distortion of a level which is not a problem with a small color cathode ray tube has been regarded as a problem.

An object of the present invention is to provide a color cathode ray tube capable of improving the strength of a shadow mask and preventing color purity from deteriorating.

[0013]

In order to achieve the above object, a color cathode ray tube according to the present invention comprises a panel having an inner surface provided with a phosphor screen, and a panel arranged opposite to the phosphor screen,
An electron gun that emits an electron beam toward the phosphor screen, a shadow mask that is disposed to face the phosphor screen and has a large number of electron beam passage holes through which the electron beams pass;
The shadow mask is formed by press molding, is formed in a substantially dome shape, and has a substantially rectangular mask main surface having the electron beam passage hole, and a mask main surface extending from a periphery of the mask main surface. A skirt portion bent in a direction substantially perpendicular to the skirt portion, a notch formed in each corner of the skirt portion to form a pair of tongue pieces, and in the skirt portion, formed near the notch,
And a plurality of openings for absorbing excess thickness of the skirt during press molding.

According to the color cathode ray tube of the present invention, each of the notches extends from the extending edge of the skirt toward the periphery of the main surface of the mask.
It is characterized in that it is provided between the extended end of the notch and the peripheral edge of the mask main surface.

According to the color cathode ray tube configured as described above, a notch is formed at each corner of the skirt to form a tongue piece, and a plurality of openings are formed in the skirt near the notch. By arranging the holes, it is possible to suppress excess material generated at the time of press-molding the shadow mask. As a result, not only the moldability of the shadow mask can be improved, but also the notch at the corner of the shadow mask can be made shallow, and the strength of the corner of the shadow mask can be improved.

As a result, the rigidity of the shadow mask is improved, and the moldability of the entire shadow mask structure can be improved. In particular, it is possible to prevent the shadow mask from being distorted into a rhombus, and to improve the landing imbalance of the color cathode ray tube. In addition, it is possible to suppress BC and SC mismatches that occur during the manufacture of a color cathode ray tube. Thereby, it is possible to suppress the displacement of the landing position of the electron beam around the screen and effectively prevent the color purity from deteriorating.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color cathode ray tube according to an embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, the color cathode ray tube device includes a vacuum envelope 10, which has a substantially rectangular panel 1 having a skirt portion 2 on its periphery and a flat outer surface, and a panel skirt. And a cylindrical neck 3 connected to the small diameter portion of the funnel.

On the inner surface of the panel 1, there are formed a plurality of phosphors respectively emitting red, green and blue light, and a phosphor screen 6 comprising a light shielding layer. A deflection yoke 7 having horizontal and vertical deflection coils is mounted on the outer periphery from the neck 3 to the funnel 4. In the neck 3, a center beam 8G and a pair of side beams 8 passing on the same horizontal plane are directed toward the phosphor of the phosphor screen 6.
An electron gun 9 that emits three electron beams in a row composed of R and 8B is arranged. Since the trajectory of the electron beam changes due to the influence of the magnetic field, an inner shield 11 that shields an external magnetic field is disposed inside the joint between the panel 1 and the funnel 4.

In the vacuum envelope 10, a shadow mask 12 is provided facing the phosphor screen 6 functioning as a phosphor screen.
Are mounted on the mask frame 14 having a rectangular shape. As will be described later, the shadow mask 12 has a mask main surface 20 in which a large number of electron beam passage holes for color identification are formed, and extends from the periphery of the mask main surface and is fixed to a mask frame 14 as described later. And a skirt portion 18 formed by press molding.
The shadow mask 12 is detachably supported on the panel by engaging an elastic support 15 fixed to the mask frame 14 with a stud pin 17 protruding from the inner surface of the skirt portion 2 of the panel 1. Have been.

The vacuum envelope 10 including the panel 1 is
A tube axis Z extending through the center of the panel and the electron gun 9, a long axis (horizontal axis) X extending perpendicular to the tube axis, a short axis (vertical axis) Y extending perpendicular to the tube axis and the long axis, have.

In the color cathode ray tube having the above structure, the three electron beams 8B and 8 emitted from the electron gun 9 are used.
G and 8R are deflected by a deflection yoke 7 mounted outside the funnel 4, and the phosphor screen 6 is horizontally and vertically scanned through an electron beam passage hole of a shadow mask 12, thereby displaying a color image.

As shown in FIG. 2, the shadow mask 12 is formed by press molding, and has a substantially rectangular mask main surface 20 formed in a gentle dome shape, and a mask main surface extending over the entire circumference of the mask main surface. And a skirt portion 18 extending substantially perpendicularly to the mask main surface from a peripheral edge 21 of the surface. The mask main surface 20 includes a substantially rectangular perforated portion 20a in which a large number of electron beam passage holes 19 are formed at a predetermined arrangement pitch, and a rectangular frame-shaped non-perforated portion 20b surrounding the perforated portion. have.

The skirt portion 18 is provided on each of the mask main surfaces 2.
A pair of long side skirt portions 18a extending from the long side
And a pair of short side skirt portions 18b each extending from the short side of the mask main surface. Skirt 18
On each side of each corner of the skirt,
A notch 26 extending from 5 to the peripheral edge 21 of the mask main surface 20 is formed. A tongue piece 30 is formed at each corner of the skirt 18 by the pair of notches 26.

Further, as shown in FIGS. 2 and 3, at each corner of the skirt portion 18, near each notch 26, there are provided a plurality of openings 32 for absorbing the excess of the skirt portion at the time of press molding. Is formed. That is, a plurality of, for example, three, openings are provided between the extended end of each notch 26 and the peripheral edge 21 of the mask main surface 20 with a gap.

As shown in FIGS. 1 and 4, the shadow mask 12 configured as described above
4, for example, each tongue piece 30 of the skirt 18, the longitudinal center of each long side skirt 18 a,
And 8 at the central portion in the longitudinal direction of each short side skirt portion 18b.
It is welded to the mask frame 14 at a point.

When manufacturing the shadow mask 12 having the above-described structure, as shown in FIGS. 5 and 6, first, a rectangular plate-shaped mask base material 40 is prepared before press molding to form a shadow mask. . An electron beam passage hole 19 is formed in advance in the perforated portion 20a of the flat mask base material 40. In addition, notches 2 are formed on each corner of the mask base material 40 in advance.
6 and a plurality of openings 32 are formed. Then, the mask base material 40 is loaded into a press device and press-formed to form a substantially rectangular mask main surface 20 formed in a dome shape and a mask main surface over the entire circumference of the mask main surface. And a skirt 18 bent substantially perpendicularly to the mask main surface from the peripheral edge 21 of the shadow mask 18.

According to the color cathode ray tube constructed as described above, the notch 26 is formed at each corner of the skirt portion 18 to form the tongue piece portion 30. In the skirt portion, a plurality of notches 26 are provided near the notch. By arranging the opening 32,
Even if a surplus occurs during the press forming of the shadow mask, the occurrence of wrinkles can be suppressed by crushing the opening 32. Thereby, even if the notch 26 is made shallow, generation of wrinkles can be prevented, and the moldability of the shadow mask 12 can be improved. By making the notch 26 at the corner of the shadow mask shallow, the strength of the corner of the shadow mask can be improved.

As a result, the rigidity of the shadow mask 12 is improved, and the moldability of the entire shadow mask structure can be improved. In particular, it is possible to prevent the shadow mask 12 from being distorted into a rhombus shape, and it is possible to improve the landing imbalance of the color cathode ray tube. In addition, it is possible to suppress BC and SC mismatches that occur during the manufacture of a color cathode ray tube. Accordingly, the landing position shift of the electron beam around the screen is suppressed, and the color purity deterioration can be effectively prevented. Furthermore, good image quality can be achieved only by using inexpensive materials that have been conventionally used without using special materials.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, as shown in FIG. 7, the opening 32 provided at the corner of the skirt 18 is formed with the notch 26 and the mask main surface 2.
It may be an elongated slit shape extending between the peripheral edge 21 of the zero.

[0030]

As described above, according to the present invention, there is provided a color cathode ray tube in which the deterioration of color purity is prevented and the image quality is improved by improving the formability and strength of the shadow mask. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a shadow mask in the color cathode ray tube.

FIG. 3 is a perspective view showing a corner portion of the shadow mask.

FIG. 4 is an exploded perspective view showing a part of the shadow mask and the mask frame.

FIG. 5 is a plan view showing a mask base material for forming the shadow mask.

FIG. 6 is an enlarged plan view showing a corner portion of the mask base material.

FIG. 7 is a perspective view showing a corner portion of a shadow mask of a color cathode ray tube according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Panel 3 ... Neck 4 ... Funnel 6 ... Phosphor screen 9 ... Electron gun 10 ... Vacuum envelope 12 ... Shadow mask 18 ... Skirt part 18a ... Long side skirt part 18b ... Short side skirt part 19 ... Electron beam Passing hole 20: Mask main surface 21: Peripheral edge 26: Notch 30: Tongue piece 32: Opening 40: Mask base material

Claims (4)

[Claims] 1. A panel having a fluorescent screen provided on an inner surface thereof, an electron gun disposed to face the fluorescent screen and emitting an electron beam toward the fluorescent screen, and disposed to face the fluorescent screen. A shadow mask having a large number of electron beam passage holes through which the electron beam passes, wherein the shadow mask is formed by press molding, is formed in a substantially dome shape, and has the electron beam passage hole. A substantially rectangular mask main surface, a skirt portion extending from the periphery of the mask main surface and bent in a direction substantially orthogonal to the mask main surface, and a pair of skirt portions formed at each corner of the skirt portion to form a tongue piece, respectively. And a plurality of openings formed in the skirt portion in the vicinity of the notch and for absorbing excess thickness of the skirt portion during press molding. Cathode-ray tube. 2. Each of the notches extends from an extending edge of the skirt portion toward a peripheral edge of the mask main surface, and the opening is formed between an extending end of the notch and a peripheral edge of the mask main surface. 2. The color cathode ray tube according to claim 1, wherein the color cathode ray tube is provided between them. 3. The collar according to claim 2, wherein a plurality of said openings are provided with a gap between the extended end of said notch and a peripheral edge of the mask main surface. Cathode ray tube. 4. The color cathode ray tube according to claim 2, wherein the opening is formed in a slit shape extending between an extended end of the notch and a peripheral edge of the main surface of the mask.