KR20020000902A - shadowmask-frame assembly for effecting uniform tension on a shadowmask in a color cathode ray tube - Google Patents

Abstract

PURPOSE: A tension shadow mask-frame assembly for a color CRT of uniform tension force is provided to effectively preventing the deformation of a shadow mask due to the temperature change during manufacturing processes according to the difference between thermal expansion factors of the shadow mask and a frame, as well as to effectively preventing doming by changing the tension along to the length of a long side of the shadow mask within doming temperature range. CONSTITUTION: A first long side member(40) of a frame is fixed to a top part of a short side member(30), and has high rigidity. A second L type long side member(50) has a bottom end(55) fixed to a top part of the first long side member(40), and a top end(51) upwardly extended from the bottom end(55) to be fixed to extend a shadow mask(80). A plurality of bimetals(60) are mounted on the second long side member(50) so that a uniform tension force is applied to prevent doming when the CRT is operated and the top end(51) is inwardly inclined to prevent plastic deformation during a heating process.

Description

{Shadowmask-frame assembly for effecting uniform tension on a shadowmask in a color cathode ray tube}

The present invention relates to a tension shadow mask-frame assembly for preventing tension force nonuniformity occurring on a long side of a shadow mask and plastic deformation of the tension mask by a thermal process, and more specifically, a tension generated on a shadow mask. In the prevention of force non-uniformity, the frame is divided into a plurality to prevent tension force non-uniformity, and in preventing plastic deformation occurring in the shadow mask during the thermal process, a strong tension causing plastic deformation is prevented from being caught by the shadow mask. Tilting the upper end of both sides of the frame by using the related art relates to a tension shadow mask-frame assembly in which the plastic mask is loosened and thermal deformation prevents plastic deformation of the tension mask.

In general, since the shadow mask is formed of a very thin sheet of 0.1mm unit does not have its own shape holding force, and thus is molded to have a predetermined curvature, it is fixed to the frame and detachably mounted on the panel. Recently, a tension shadow mask-frame assembly has been developed in which a fixed tension is applied to a shadow mask to prevent the ming.

The shadow mask-frame assembly to which such tension is applied is heated when passing through a thermal process around 450 ° C. in a manufacturing process such as a screen, and then cooled through a predetermined stabilization time.

However, since the heat capacity of the mask during cooling is relatively smaller than that of the frame, and thus cools more rapidly than the frame, a second tension force is applied to the mask in the cooling process, thereby causing tensile deformation. That is, since the mask before the thermal process is already stretched by the equivalent ratio of the elastic limit (70 to 80% of the tensile strength), when another deformation force is applied during the thermal process, the mask is plastically deformed beyond the material elastic limit, The elastic force is lost and placed in a loose state. Tension shadow mask-frame assemblies of cathode ray tubes have been developed to prevent plastic deformation.

The tension shadow mask-frame assembly of the cathode ray tube for preventing plastic deformation of the cathode ray tube is a frame composed of a long side member and a short side member and a shadow mask of the long side member as in the prior art. By arranging two different metals, plastic deformation in the thermal process is prevented.

In one example of the assembly, first, the shadow mask 8 and the frame 2 are respectively tensioned and compressed by a mechanical method, and the tensioned shadow mask 8 is welded to the frame long side member 5 to fix the frame short side. It is comprised by attaching two metals from which thermal expansion differs to the lower part of the member 3.

However, such a conventional tension shadow mask-frame assembly still has a problem that plastic deformation is not completely removed by the thermal process in the shadow mask, so that deformation cannot be avoided, and thus, initially applied to the shadow mask 8. There is a problem in that the tension force is limited so that it cannot function as a perfect tension mask.

In addition, such a conventional tension shadow mask-frame assembly has a strong stiffness at the portion where the short side member and the long side member are fixed, so that a large tension force is applied to the shadow mask, but the tension force is weakly applied to the shadow mask as it moves away from the fixed portion. As a result, a phenomenon in which the tension force becomes nonuniform occurs, and thus there is a problem in that it is impossible to completely prevent doming.

Accordingly, the present invention is to solve such a problem, it is effective to prevent the deformation of the shadow mask due to the temperature change during the manufacturing process due to the difference in the coefficient of thermal expansion between the shadow mask and the frame, and the long side of the member It is an object of the present invention to provide a tension shadow mask-frame assembly of a cathode ray tube that can change the tensile force along its length to effectively prevent doming.

1 is a schematic perspective view illustrating a conventional tension shadow mask-frame assembly;

FIG. 2 is a schematic diagram for explaining an uneven tensile force distribution occurring in a frame of the tension shadow mask-frame assembly of FIG. 1; FIG.

3 is a perspective view illustrating a tension shadow mask-frame assembly of a cathode ray tube according to an embodiment of the present invention;

4 is a schematic diagram illustrating a uniform stress distribution occurring in a frame of the tension shadow mask-frame assembly in FIG. 3;

FIG. 5 is a partial cross-sectional view illustrating a process of fixing the shadow mask in a state in which an external force is applied to the second long side member in order to tension the shadow mask of the tension shadow mask-frame assembly of FIG. 3; FIG.

6 is a partial cross-sectional view showing a state in which the tension is applied to the shadow mask by removing the external force in FIG.

FIG. 7 is a partial cross-sectional view illustrating a state in which a bimetal is fixed between a first long side member and a second long side member of the tension shadow mask frame assembly of FIG. 6; FIG.

FIG. 8 is a partial cross-sectional view illustrating a state in which a bimetal mounted on the tension shadow mask-frame assembly of FIG. 7 is thermally expanded in a thermal process so that the frame is bent inwardly;

9 is a perspective view illustrating a tension shadow mask frame assembly according to another embodiment of the present invention.

<Explanation of symbols about main part of drawing>

9: tensile force size

20: frame 30: short side member

40: first long side member 5,50: second long side member

51: upper 52: division

55: bottom 60, 70: bimetal

61, 71: low thermal expansion member 62, 72: high thermal expansion member

8,80: shadow mask

Tension shadow mask frame assembly according to an embodiment of the present invention for solving the above object, a pair of short side member and long side parallel to the short side and long side of the shadow mask and the shadow mask that serves as the color selection of the electron beam, respectively In a color cathode ray tube having a frame made of a member, wherein the shadow mask is tensioned by the long side member: The long side member is a first long side member fixed to an upper portion of the short side member and having a high rigidity, and the first side member. It consists of an L-shaped second long side member having a lower end fixed to the upper part of the long side member, and an upper end formed extending from the lower end to the upper end and fixed to extend the shadow mask, and preventing the doming during operation of the cathode ray tube. The upper end is inward to prevent the plastic deformation when heated in the thermal process during the manufacturing process. The incline of a plurality of bimetallic characterized in that provided on the second long side member.

In this case, the bimetal is composed of three parts divided into a central part and two side parts, thereby ensuring uniformity of tension force effectively even with a small number of divisions, and by using different thicknesses, lengths, and materials, respectively. It is easier to ensure uniformity. In addition, by dividing the upper end into a plurality of the same as the plurality of bimetal, it is possible to minimize the influence of the resistance due to the rigidity of the upper end.

In addition, the present invention has a shadow mask that serves as the color selection of the electron beam, and a frame composed of a pair of short side members and long side members parallel to the short side and long side of the shadow mask, respectively, the shadow mask is tensioned by the long side member In the color cathode ray tube which is subjected to: The long side member is fixed to the upper portion of the first long side member, and fixed to the upper portion of the short side member, and fixed to the upper portion of the first long side member at the bottom, so that the shadow mask is extended from the upper side It is fixed and composed of a large number of L-shaped bimetals, so that a uniform tension force acts on the shadow mask to prevent doming during operation of the cathode ray tube, and plastic deformation when heated in the thermal process during the manufacturing process. To provide a tension shadow mask-frame assembly, the upper portion is inclined inward to prevent the The.

Even in such a structure, the bimetal is composed of three parts divided into a central part and two side parts, and further, by using different thicknesses, lengths, and materials, it is possible to easily secure uniformity of tension force.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a perspective view of a structure of a tension shadow mask-frame assembly of a cathode ray tube according to an embodiment of the present invention.

Tension shadow mask-frame assembly for preventing the tension force non-uniformity occurring in the preferred shadow mask long side according to an embodiment of the present invention, as shown in Figure 3 to 8, basically a pair of short side member (30) ) And a pair of long side members 40 and 50, and the long side members 40 and 50 are composed of a first long side member 40 and a second long side member 50, respectively. A plurality of bimetals 60 are fixed between the 40 and the second long side member 50.

The first long side member 40, as shown in the shape □ in the drawing, is formed of a structure having a rigid, fixed to the short side member 30 to form a basic frame frame.

The second long side member 50 is divided into an L-shaped lower end 55 and an upper end 51, and the lower end 55 is fixed to an upper portion of the first long side member 40, and the upper end 51 is a lower end. It is formed extending from the upper portion 55, the shadow mask 80 is fixed to the upper end 51 to extend.

The bimetal 60 is composed of a high thermal expansion member 62 and a low thermal expansion member 61 so that the upper end 51 is inclined inward to prevent plastic deformation when heated in the thermal process during the manufacturing process. It is fixed between the one long side member 40 and the second long side member 50. In addition, the bimetal 60 has a plurality of parts, preferably divided into a central part and two side parts, so as to uniformly apply a tension force applied to the shadow mask 80 so as to prevent doming during operation of the cathode ray tube. And is fixed between the first long side member 40 and the second long side member 50. In addition, the plurality of bimetals 60 can easily adjust the uniformity according to the length of the tension force acting on the upper end 51 by using different thicknesses, lengths, and materials.

Furthermore, since the upper end 51 is divided into a plurality of the same as the plurality of bimetals 60, the influence of the resistance force due to the rigidity of the upper end 51 can be minimized, so that the tension force can be more easily uniformized. Will be.

The detailed operation of the tension shadow mask-frame assembly for preventing tension force nonuniformity occurring on the long side of the shadow mask according to an embodiment of the present invention configured as described above will be described with reference to FIGS. 3 to 8.

In FIG. 5, while pressing the upper end of the second long side member 50 to the inside, the shadow mask 80 is welded and fixed to the upper end of the second long side member 50 while tensioning the shadow mask 80 to the outside. After releasing the pressing force and the tensile force, the tension force acts on the shadow mask 80 as shown in FIG.

At this time, the first long side member 40 is fixed to the pair of short side members 30, the second long side member 50 is fixed to the upper surface of the first long side member 40 at its lower end 55 By changing the action force by a plurality of bimetals 60, for example, the bimetal 60 of the two sides and the central portion separated by the divided portion 52 in the uniform tension force as shown in FIG. 80). That is, the force acting outward on the second long side member 50 by the bimetal 60 in the center portion at the doming temperature in FIG. 3 is stronger than the force acting outward by the bimetal 60 on both sides. Since the thickness, material, and the like are changed, the tension force acting on the shadow mask 80 is made uniform as shown in FIG. 4.

In addition, in the thermal process during the manufacturing process, when heated and extended, the upper end 51 is inclined inward as shown in FIG. 8, so that the tension mask is applied by the upper end 51 so that the shadow mask is tightly fixed. 80 is loosened without being subjected to tension. Then, after cooling, the heat capacity of the shadow mask 80 is relatively small compared to the frame, so that it is cooled more rapidly than the frame, but due to the relative high temperature of the frame higher than the shadow mask 80, the bimetal 60 is still in a state similar to that of FIG. It will not maintain the excessive tension force on the shadow mask (80). Accordingly, plastic deformation is not generated in the shadow mask 80 even during cooling in the thermal process.

Another preferred tension shadowmask-frame assembly according to the present invention is shown in FIG. 9. In FIG. 9, as in the above embodiment, the frame constitutes a basic frame with a pair of short side members 30 and a first long side member 40, but unlike the above embodiment, instead of the second long side member 50 A plurality of L-shaped divided bimetals 70 composed of a low thermal expansion member 71 and a high thermal expansion member 72 are fixed to the upper portion of the first long side member 40 at the bottom thereof. The shadow mask 80 is secured to the top of the bimetal 70 to extend.

The first long side member 40 is the same as in the above-described embodiment, and in this embodiment, the bimetal 70 is formed in an L shape divided into a plurality, so that the tension is uniform in preventing the doming during operation of the cathode ray tube. It is possible to change the material, thickness and the like so that the force acts on the shadow mask 80 to act a uniform tension force as described in the above-described embodiment with respect to FIGS. In the thermal process of, similarly to FIG. 8, plastic deformation is prevented.

According to the configuration and action of the tension shadow mask-frame assembly for preventing tension force unevenness occurring on the long side of the shadow mask according to an embodiment of the present invention, the tension of the frame is applied to the shadow mask of the cathode ray tube Non-uniform stress distribution by applying the bimetal (60, 70) divided in the frame to prevent plastic deformation in the thermal process and to apply a uniform tension force to the shadow mask 80 to improve the image quality of the screen It can be effective.

While the present invention has been shown and described with respect to certain preferred embodiments, it is not limited to this and various modifications can be made by those of ordinary skill in the art without departing from the spirit of the invention or the scope of the following claims. Applications and variations will be possible.

Claims (5)

A color cathode ray tube having a shadow mask which plays a role of color selection of an electron beam, and a pair of short side members and a long side member parallel to the short and long sides of the shadow mask, respectively, wherein the shadow mask is tensioned by the long side member. In: The long side members 40 and 50 may be fixed to the upper side of the short side member 30 and have a first long side member 40 having strong rigidity, and a lower end 55 fixed to the upper side of the first long side member 40. And an L-shaped second long side member 50 extending from the lower end 55 to the upper end and having an upper end 51 to which the shadow mask 80 is extended. A tension shadow mask frame assembly, characterized in that a plurality of bimetals (60), the inner side of which is a low thermal expansion member and the outer side of a high thermal expansion member, is fixed to the first long side member (40) and the second long side member (50). The tension shadow mask frame assembly of claim 1, wherein the plurality of bimetals (60) is composed of three parts divided into a central part and two side parts, and each uses different thicknesses, lengths, and materials. The tension shadow mask frame assembly according to claim 1, wherein the upper end is divided into a plurality of bimetals. A color cathode ray tube having a shadow mask which plays a role of color selection of an electron beam, and a pair of short side members and a long side member parallel to the short and long sides of the shadow mask, respectively, wherein the shadow mask is tensioned by the long side member. In: The long side members 40 and 70 are fixed to the upper side of the short side member 30 and have a first rigid side member 40 having strong rigidity, and fixed to the upper side of the first long side member 40 at the bottom and to the shadow from the top side. Tension shadow mask-frame assembly, characterized in that the mask (80) is elongated fixed and consists of a plurality of L-shaped bi-metal (70). The tension shadow mask-frame assembly according to claim 4, wherein the bimetal (70) is composed of three parts divided into a central part and two side parts, and uses different thicknesses, lengths, and materials.