JP2001135255A - Shadow mask body and color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent apertures of a shadow mask that pass an electron beam from shifting from the original position, to cause lowering of color purity of the screen by reducing vibration of neighbors of two free sides of the mask in resonance with external vibration. SOLUTION: Provided at nonperforated portion of two free sides of a shadow mask 102 is a notch 102B that does not reach a perforated portion 102C. As a result, vibration of he shadow mask 102 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask assembly for a color cathode ray tube, and more particularly to a shadow mask assembly having a structure in which a shadow mask is stretched in one direction, and a color cathode ray tube having the shadow mask assembly.

[0002]

2. Description of the Related Art In recent years, color CRTs having a substantially flat glass panel surface, called flat tubes, have been increasing.
FIG. 7 shows a partial cross-sectional perspective view of a glass panel 700 for a flat tube. In the figure, reference numeral 701 denotes the surface of the glass panel (outside the color cathode ray tube), and 702 denotes the inner surface of the glass panel (inside the color cathode ray tube). As shown in the figure, even when the glass panel surface 701 is substantially flat, the cross section of the glass panel is thicker at the periphery than at the center, and the glass panel 700 has a concave lens shape formed by a part of a cylindrical surface. The first reason for this is that if the thickness of the glass at the periphery is the same as that at the center, the pressure resistance of the glass bulb is reduced, and the risk of implosion of the color cathode ray tube is great. Second, if the thickness of the glass at the periphery is the same as that at the center, the image of the color cathode-ray tube is dented and unnatural. In order to prevent implosion and make the image appear flat, the glass panel for the flat tube has a thicker glass at the periphery than at the center.

[0003] Since the inner surface 702 of the glass panel has a concave lens shape composed of a part of a cylindrical surface as described above, the conventional shadow mask is adapted to the inner surface 70 of the glass panel.
It is formed in a shape consisting of a part of a cylindrical surface almost similar to 2. This is hereinafter referred to as a cylindrical shadow mask.

FIG. 8 is a perspective view of a conventional shadow mask structure 800. In the figure, 801 is a mask frame, 8
02 is a shadow mask (only the surroundings are displayed so that the inside of the mask frame 801 is easy to see), and 802A is a shadow mask welding point.

[0005] A tension is applied to the shadow mask 802 from two sides of the mask frame 801 via a shadow mask welding point 802A. Since it is difficult to apply tension from four directions to a cylindrical shadow mask, it is general to apply tension from two directions in this way.

[0006]

Problems with the conventional shadow mask structure 800 will be described with reference to FIG. FIG. 9 shows a shadow mask 80 of a conventional shadow mask structure 800.
FIG. 2 is a plan view of FIG. In the figure, a hatched portion 802B is a region with insufficient tension, 802C is a perforated portion, 802D is a non-perforated portion, 802
E is an electron beam passage hole. The approximate dimensions of the shadow mask 802 are about 3 long sides for a 19-inch color CRT.
70 mm, short side about 280 mm, thickness 0.1 mm.
The width of the non-porous portion 802D is 4 mm on one side. As described above, since tension is applied only to two sides (upper and lower sides in FIG. 9) of the shadow mask 802, two sides perpendicular to the two sides (left and right sides in FIG. 9) are in a free state. . As described above, the shadow mask is approximately 280 mm long and approximately 3 mm wide.
The shadow mask is not rigid because it has a thickness of only about 0.1 mm despite its size of 70 mm. Therefore, sufficient tension is not applied to the tension-deficient region 802B near the two free sides. Therefore, when external vibration from a speaker or the like is transmitted to the shadow mask 802,
The insufficient tension region 802B resonates and vibrates. According to the experiment of the inventor, in the conventional shadow mask structure 800 in which the two sides of the shadow mask 802 are free, the shadow mask 8
02 with a single impact on the under tension area 802B
Vibration lasts for about 60 to 120 seconds. Shadow mask 802
During the vibration of the electron beam passing hole 8 of the shadow mask 802.
02E deviates from the original position, so that the color purity decreases.
Therefore, the color cathode-ray tube provided with the conventional shadow mask structure 800 has a problem that the color purity often decreases at the left and right peripheral portions of the screen.

To solve the above problem, Japanese Patent Laid-Open Publication No. 8-77936 discloses a structure in which a T-shaped, Z-shaped or coil spring-shaped vibration damper is brought into contact with two free sides of a shadow mask to prevent vibration. JP-A-9-274
867 and Japanese Patent Application Laid-Open No. 9-274868. However, in the structures disclosed in these documents, it is necessary to manufacture a vibration damping body having a complicated shape and incorporate it with high precision so that the shadow mask is not deformed. Therefore, there are problems in that parts costs and assembly costs are increased, and the weight of the shadow mask structure is increased.

[0008] In the shadow mask structure of the present invention,
By devising the shape of the shadow mask itself, sufficient tension is applied to the two free sides of the shadow mask. As a result, the vibration of the shadow mask can be reduced to a practically acceptable level without adding a new component such as a vibration damper. As a result, the component cost and the assembly cost of the shadow mask structure of the present invention are the same as those of the conventional shadow mask structure, and the weight is lighter than the conventional shadow mask structure. Therefore, by providing the shadow mask structure of the present invention, a low-cost, lightweight, and high-quality color CRT can be realized.

[0009]

In order to achieve the above object, a shadow mask structure according to the present invention has a structure in which a shadow mask reaches a perforated portion at both end non-porous portions on two sides where tension is not applied. It is characterized by having a notch which is not used.

That is, a first aspect of the present invention is a shadow mask structure comprising a substantially rectangular frame-shaped mask frame and a substantially rectangular shadow mask having a pair of long sides stretched over the mask frame. The shadow mask is characterized in that a cutout that does not reach the perforated portion is provided in the non-perforated portion on both ends on the short side.

According to a second aspect of the present invention, the shape of the notch is substantially rectangular or substantially trapezoidal, and the length of the notch along the short side of the shadow mask is short. It is characterized by being 10% to 90% of the total length of the side.

According to a third aspect of the present invention, the notch has a substantially arc shape, and the notch has
The length of the shadow mask along the short side is 10% to 100% of the entire length of the short side.

According to a fourth aspect of the present invention, the material of the mask frame is 13 chrome stainless steel, and the material of the shadow mask is Invar.

According to a fifth aspect of the present invention, in a shadow mask structure comprising a substantially rectangular frame-shaped mask frame and a substantially rectangular shadow mask, a pair of mask supports are provided on a pair of long sides of the mask frame. Body, the shadow mask is stretched over the pair of long sides of the mask support, and a cutout that does not reach a perforated portion is provided at a non-perforated portion at both short side ends of the shadow mask. It is characterized by.

In a sixth aspect of the present invention, the shape of the notch is substantially rectangular or substantially trapezoidal, and the length of the notch along the short side of the shadow mask is short. It is characterized by being 10% to 90% of the total length of the side.

According to a seventh aspect of the present invention, the notch has a substantially arc shape, and the notch has
The length of the shadow mask along the short side is 10% to 100% of the entire length of the short side.

According to an eighth aspect of the present invention, the material of the mask frame is 13 chrome stainless steel, and the material of the mask support and the shadow mask is Invar.

According to a ninth aspect of the present invention, the shape of the electron beam passage hole of the shadow mask is substantially rectangular having a longitudinal direction parallel to a short side of the shadow mask. And

According to a tenth aspect of the present invention,
A color CRT comprising the shadow mask structure according to claim 1.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the shadow mask structure of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a shadow mask structure 100 according to a first embodiment of the present invention. In the figure, 101 is a mask frame, 102 is a shadow mask (only the surroundings are displayed so that the inside of the mask frame 101 is easy to see), 102A is a shadow mask welding point, and 102B is a cutout of the shadow mask 102.
2C is a perforated portion of the shadow mask 102.

Tension is applied to the shadow mask 102 from two sides (long sides) of the mask frame 101 via the shadow mask welding point 102A.

The mask frame 101 is a 13 mm chrome stainless material having a thickness of 2.2 mm, and the shadow mask 102 is an invar material having a thickness of 0.1 mm. Shadow mask structure 1
The approximate dimensions of 00 are 360 mm long, 270 mm short, and 43 mm high, and are for a 19-inch color CRT.

FIG. 2 shows a first example of the shadow mask 10 provided in the shadow mask structure 100 of the first embodiment of the present invention.
FIG. 2 is a plan view of FIG. In the figure, 102B is a notch, 1
02C is a perforated portion, 102D is a non-perforated portion, and 102E is an electron beam passage hole. The approximate dimensions of the shadow mask 102 are about 370 mm on a long side, about 280 mm on a short side, and 0.1 mm in thickness.
It is. The width of the non-porous portion 102D is 4 mm on one side.
The notch 102B has a trapezoidal shape and is located at the center of the short side of the shadow mask 102, and its dimensions are short side 120mm and long side 140m.
m, depth of cut 3 mm. Electron beam passage hole 10
2E is a substantially rectangular shape having a length of approximately 260 μm and a width of approximately 60 μm, and its long side is parallel to the short side of the shadow mask 102. As shown, the electron beam passage holes 102E are vertically shifted by half a pitch for each adjacent row.

When the notch 102B is formed in the non-perforated portion 102D of the shadow mask 102, a part of the tension-deficient region 802B of the conventional shadow mask 802 having no notch is cut off and no longer exists. Then shadow mask 10
2, the area of the tension-deficient region where vibration easily occurs is reduced, and the tension of the remaining non-porous portion 102D is further increased. Therefore, the amplitude of vibration at the left and right ends of the short side of the shadow mask 102 is reduced, and the vibration is attenuated. Be faster. According to an experiment performed by the inventor, the conventional shadow mask structure 8 was subjected to the same impact.
Compared with the shadow mask structure 100, the shadow mask structure 100 according to the first embodiment of the present invention has an amplitude of about ２ and a decay time of about ６.
(About 10 seconds). When the vibration is reduced to such a degree, the decrease in color purity on the screen can hardly be recognized.

That is, the shadow mask structure 10 of the present invention
0, the non-porous portion 102D of the shadow mask 102
By inserting the notch 102B into the hole, the vibration of the shadow mask resonating with the external vibration, which has conventionally been a problem,
In addition, it is possible to prevent a decrease in color purity of a screen due to the above. The shadow mask structure 10 of the present invention
0, the shadow mask 10
2 is cut off, so that the shadow mask 102 is reduced in weight. Since there are no additional components, the weight of the entire shadow mask structure 100 is reduced. Therefore, the entire color CRT can be reduced in weight.

The length of the notch 102B in this embodiment is 140 mm as described above, which is 50% of the length 280 mm of the short side of the shadow mask 102. When the shape of the notch 102B is a rectangle or a trapezoid close to a rectangle, the maximum length of the notch 102B is 90% of the short side length.
Beyond this, the non-porous portion 102 of the shadow mask 102
Another problem occurs because the strength of D decreases.

FIG. 3 shows a second example of the shadow mask 10 provided in the shadow mask structure 100 of the first embodiment of the present invention.
3 is a plan view of FIG. In the figure, 103B is a notch, 1
03C is a perforated portion, 103D is a non-perforated portion, and 103E is an electron beam passage hole. The approximate dimensions of the shadow mask 103 are about 370 mm on a long side, about 280 mm on a short side, and 0.1 mm in thickness.
It is. The width of the non-porous portion 103D is 4 mm on one side.
The notch 103B is rectangular and is located at the center of the short side of the shadow mask 103, and its dimensions are 28 mm long and 3 mm wide (cut depth). The electron beam passage hole 103E is substantially rectangular with a length of approximately 260 μm and a width of approximately 60 μm, and its long side is parallel to the short side of the shadow mask 103. As shown, the electron beam passage holes 103E are vertically shifted by a half pitch for each adjacent row.

By the same mechanism as described for the shadow mask 102 of FIG. 2, the shadow mask 103 is also provided with a cutout 103B in the non-porous portion 103D.
, The amplitude of the vibration at the left and right ends of the short side of the shadow mask 103 is reduced, and the vibration is attenuated faster. This makes it possible to prevent the vibration of the shadow mask 103 resonating with the external vibration and the reduction of the color purity of the screen due to the vibration.

The notch 10 of the shadow mask 103
The length of 3B is 28 mm, which is 10% of the length 280 mm of the short side of the shadow mask 103. When the shape of the notch 103B is a rectangle or a trapezoid close to a rectangle, the notch 1
The minimum length of 03B is 10% of the short side length. If the notch length is less than the minimum, the effect of reducing the vibration of the shadow mask 103 is insufficient.

FIG. 4 shows a third example of the shadow mask 10 provided in the shadow mask structure 100 of the first embodiment of the present invention.
FIG. 4 is a plan view of FIG. In the figure, 104B is a notch, 1
04C is a perforated portion, 104D is a non-perforated portion, and 104E is an electron beam passage hole. The approximate dimensions of the shadow mask 104 are about 370 mm on a long side, about 280 mm on a short side, and 0.1 mm in thickness.
It is. The width of the non-porous portion 104D is 4 mm on one side.
The notch 104B is rectangular and is located at the center of the short side of the shadow mask 104 and symmetrically above and below the shadow mask 104.
0 mm and horizontal (cut depth) 3 mm. The electron beam passage hole 104E is substantially rectangular with a length of approximately 260 μm and a width of approximately 60 μm, and its long side is parallel to the short side of the shadow mask 104. As shown, the electron beam passage hole 104E
Are vertically shifted by half a pitch for each adjacent row.

In the shadow mask 104, a plurality of notches 1 are formed in the non-porous portion 104D by the same mechanism as described for the shadow mask 102 in FIG.
When 04B is inserted, the amplitude of the vibration at the left and right ends of the short side of the shadow mask 104 is reduced, and the vibration is attenuated faster. As a result, the shadow mask 10 resonated with external vibration
It is possible to prevent the vibration of No. 4 and the decrease in the color purity of the screen caused by the vibration. In the case where the shape of the notch 104B is a rectangle or a trapezoid close to a rectangle, the notch 104B
When B is plural, the total length of each notch 104B is 10% to 90% of the length of the short side of the shadow mask 104.
%.

FIG. 5 shows a fourth example of the shadow mask 10 provided in the shadow mask structure 100 of the first embodiment of the present invention.
5 is a plan view of FIG. In the figure, 105B is a notch, 1
05C is a perforated portion, 105D is a non-perforated portion, and 105E is an electron beam passage hole. The approximate dimensions of the shadow mask 105 are a long side of about 370 mm, a short side of about 280 mm, and a thickness of 0.1 mm.
It is. The width of the non-porous portion 105D is 4 mm on one side.
The notch 105B has an arc shape and the size is 240m in length.
m, width (cut depth) 3 mm. The electron beam passage hole 105E is substantially rectangular with a length of approximately 260 μm and a width of approximately 60 μm, and its long side is parallel to the short side of the shadow mask 105. As shown, the electron beam passage holes 105E are vertically shifted by half a pitch for each adjacent row.

With the same mechanism as that described for the shadow mask 102 of FIG. 2, if the arc-shaped notch 105B is formed in the non-porous portion 105D, the left and right ends of the short side of the shadow mask 105 are also formed. As the amplitude of the vibration becomes smaller, the attenuation of the vibration becomes faster. As a result, the shadow mask 1 resonates with external vibration.
05, and a decrease in the color purity of the screen caused by the vibration can be prevented. When the shape of the notch 105B is an arc shape, the length of the notch 105B needs to be 10% to 100% of the length of the short side of the shadow mask 105. The reason is that if it is less than 10%, the effect of preventing vibration is insufficient. In addition, when the shape of the notch 105B is an arc, even if the length of the notch 105B becomes 100% of the length of the short side of the shadow mask 105, no problem such as strength occurs.

FIG. 6 is a perspective view of a shadow mask structure 600 according to the second embodiment of the present invention. In the figure, 601 is a mask frame, 602 is a mask support, 603 is a shadow mask (only the surroundings are shown so that the inside of the mask frame 601 is easy to see), 603A is a shadow mask welding point, 603
B is a cutout of the shadow mask 603, and 603C is a perforated portion of the shadow mask 603.

The tension is applied to the shadow mask 603 from two sides (long sides) of the mask frame 601 via the shadow mask welding point 603A and the mask support 602.

The mask frame 601 has a thickness of 2.2 mm and is made of 13 chrome stainless steel, and the mask support 602 has a thickness of 3 mm.
mm Invar material, shadow mask 603 has a thickness of 0.1
mm invar material. The approximate dimensions of the shadow mask structure 600 are long side 360 mm, short side 270 mm, and height 43.
mm for 19-inch color CRT.

In the shadow mask structure 100 according to the first embodiment of the present invention, the shadow mask 102 is directly welded to the mask frame 101. In this case, the shadow mask 102 is an invar material having a low coefficient of thermal expansion (about 1.2 ppm at room temperature), and the mask frame 101 is a 13 chrome stainless material having a coefficient of thermal expansion about 10 times that of the invar material. During use of the color cathode ray tube, an electron beam is incident on the shadow mask 102, and the temperatures of the shadow mask 102 and the mask frame 101 rise to a maximum of about 100 ° C. Therefore, thermal expansion mismatch between the shadow mask 102 and the mask frame 101 may occur, and the shadow mask 102 may be distorted.

On the other hand, in the shadow mask structure 600 according to the second embodiment of the present invention, since the shadow mask 603 is welded to the mask support 602 made of the same invar material, the distance between the shadow mask 603 and the mask support 602 is increased. No thermal expansion mismatch occurs. Therefore, there is no possibility that the shadow mask 603 is distorted.

As examples of the shadow mask provided in the shadow mask structure 600 of the second embodiment of the present invention, the shadow mask 102 of the first example, the shadow mask 103 of the second example, and the shadow of the third example have already been described. The mask 104 and the shadow mask 105 of the fourth example are preferable. The first to fourth examples of the shadow masks 102, 103, 104, 1
At 05, the mechanism for preventing vibration of the shadow mask is as described above.

[0040]

As described above, in the shadow mask structure according to the present invention, the shadow mask is provided with notches that do not reach the perforated portions at the non-perforated portions on both sides of the shadow mask where no tension is applied. As a result, the area of the tension-deficient region that is likely to vibrate is reduced, and the tension of the remaining non-porous portion is increased. As a result, the vibration of the shadow mask could be reduced to a practically acceptable level without adding a new component such as a vibration damper. Further, the cost of parts and assembly of the shadow mask structure of the present invention is not different from the conventional one, and the weight is rather lighter than the conventional shadow mask structure. By providing the shadow mask structure of the present invention, a color CRT with low cost, light weight, and good image quality was realized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a shadow mask structure according to a first embodiment of the present invention.

FIG. 2 is a plan view of a first example of a shadow mask provided in the shadow mask structures of the first and second embodiments of the present invention;

FIG. 3 is a plan view of a second example of a shadow mask provided in the shadow mask structures of the first and second embodiments of the present invention.

FIG. 4 is a plan view of a third example of a shadow mask provided in the shadow mask structures of the first and second embodiments of the present invention.

FIG. 5 is a plan view of a fourth example shadow mask provided in the shadow mask structures of the first and second embodiments of the present invention.

FIG. 6 is a perspective view of a shadow mask structure according to a second embodiment of the present invention.

FIG. 7 is a partial sectional perspective view of a glass panel for a flat tube.

FIG. 8 is a perspective view of a conventional shadow mask structure.

FIG. 9 is a plan view of a shadow mask provided in a conventional shadow mask structure.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 shadow mask structure 101 mask frame 102 shadow mask 102A shadow mask welding point 102B shadow mask notch 102C shadow mask hole 102D shadow mask non-hole 102E electron beam passage hole 103 shadow mask 103B shadow mask notch 103C Hole portion of shadow mask 103D Non-hole portion of shadow mask 103E Electron beam passage hole 104 Shadow mask 104B Notch of shadow mask 104C Hole portion of shadow mask 104D Non-hole portion of shadow mask 104E Electron beam passage hole 105 Shadow mask 105B Notch of shadow mask 105C Perforated portion of shadow mask 105D Non-perforated portion of shadow mask 105E Electron beam passage hole 600 Shadow mass Structure 601 Mask frame 602 Mask support 603 Shadow mask 603A Shadow mask welding point 603B Notch of shadow mask 603C Perforated portion of shadow mask 700 Glass panel for flat tube 701 Glass panel surface 702 Glass panel inner surface 800 Shadow mask structure 801 Mask frame 802 Shadow mask 802A Shadow mask welding point 802B Insufficient tension area 802C Perforated part 802D Non-perforated part

Claims (10)

[Claims] 1. A shadow mask structure comprising: a substantially rectangular frame-shaped mask frame; and a substantially rectangular shadow mask having a pair of long sides stretched over the mask frame; A shadow mask structure, wherein a hole is provided with a notch that does not reach the hole. 2. The shadow mask structure according to claim 1, wherein the shape of the notch is substantially rectangular or substantially trapezoidal, and the length of the notch along the short side of the shadow mask is short. A shadow mask structure characterized by being 10% to 90% of the total side length. 3. The shadow mask structure according to claim 1, wherein the shape of the notch is substantially circular, and the length of the notch along the short side of the shadow mask is the short side. A shadow mask structure characterized by being 10% to 100% of the entire length. 4. The shadow mask structure according to claim 1, wherein the material of the mask frame is 13 chrome stainless steel, and the material of the shadow mask is Invar. 5. A shadow mask structure comprising a substantially rectangular frame-shaped mask frame and a substantially rectangular shadow mask, comprising: a pair of mask supports on a pair of long sides of the mask frame; A shadow mask structure having a pair of long sides stretched over a mask support, and a cutout that does not reach a perforated portion is provided at a non-porous portion on both ends on a short side of the shadow mask. 6. The shadow mask structure according to claim 5, wherein the shape of the notch is substantially rectangular or substantially trapezoidal, and the length of the notch along the short side of the shadow mask is short. A shadow mask structure characterized by being 10% to 90% of the total side length. 7. The shadow mask structure according to claim 5, wherein the shape of the notch is substantially circular, and the length of the notch along the short side of the shadow mask is the short side. A shadow mask structure characterized by being 10% to 100% of the entire length. 8. The shadow mask structure according to claim 5, wherein the material of the mask frame is 13 chrome stainless steel, and the material of the mask support and the shadow mask is Invar. 9. The shadow mask structure according to claim 1, wherein the shape of the electron beam passage hole of the shadow mask is substantially rectangular having a longitudinal direction in a direction parallel to a short side of the shadow mask. A shadow mask structure characterized by the following. 10. A color cathode ray tube provided with the shadow mask structure according to claim 1.