KR20060012884A - Mask frame - Google Patents

Abstract

The present invention relates to a mask frame to reduce the influence of the increase of the external magnetic field due to the reduction of the area of the shadow mask to be welded and fixed to the mask frame and to improve the durability of the mask frame, and a hole having a plurality of electron beam through holes A mask frame welded and fixed to the shadow mask to support a shadow mask having a non-hole positioned at an outer edge of the hole and a tip portion extending vertically from the non-hole, wherein the mask frame protrudes toward the tip side. It includes a bead formed to face the front end portion, it is possible to greatly reduce the influence of the geomagnetic or external magnetic field caused by the increase in the distance between the mask frame and the shadow mask, the strength of the frame is increased to increase durability Will improve, howl Further characteristics can be improved there is an effect that increase the reliability of the product significantly.

Shadow mask, mask frame, bead, tip, electron beam

Description

Mask frame             

1 is a cross-sectional view showing the structure of a typical cathode ray tube,

2 is a diagram showing the structure of a typical shadow mask;

3 is a view illustrating a combination structure of a typical shadow mask and a mask frame;

4 is a view showing a combination structure of a shadow mask and a mask frame according to the prior art,

FIG. 5 illustrates the influence of a magnetic field on an electron beam in a shadow mask and mask frame combining structure according to the prior art; FIG.

6 is a view showing a structure of a shadow mask according to the present invention;

7 is a perspective view illustrating a shadow mask and a mask frame coupling structure according to the present invention;

8 is a view showing in detail the structure of a mask frame according to the first embodiment of the present invention;

9 is a diagram illustrating a structure of a mask frame according to a second embodiment of the present invention.

<Explanation of symbols on main parts of the drawings>                 

50: shadow mask 51: tongue section

52: distal end 54: distal end

60: mask frame 61: bead

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mask frame, and more particularly, to a mask frame for reducing the influence of an increasing external magnetic field due to the reduction of the area of a shadow mask welded to the mask frame and improving the durability of the mask frame.

1 is a cross-sectional view showing the structure of a general color cathode ray tube.

A general color cathode ray tube basically comprises a panel 1, a funnel 2, a shadow mask 4, a screen 3, a deflection yoke 6, and an electron gun 5.

The panel 1 is a portion corresponding to the screen, and forms a part of the vacuum container, and at the same time, image information is converted into final visual information, and the funnel 2 is connected to the panel 1 to connect the vacuum container. The shadow mask 4 has an electron beam such that an electron beam of three colors R, G, and B emitted from the electron gun 5 can reach the screen 3 formed inside the panel 1 accurately. A plurality of electron beam passing holes that can pass through are formed.

In addition, the deflection yoke 6 is the most important element of the magnetic device of the color cathode ray tube, and scans the electron beam up, down, left and right so that an electric signal transmitted in time series is reproduced in a two-dimensional image in the cathode ray tube.

Therefore, the color cathode ray tube constructed as described above is the screen in which the electron beam is formed on the inner surface of the panel 1 by an anode voltage applied to the cathode ray tube in the electron gun 5 embedded in the neck of the funnel 2. The electron beam is deflected up, down, left and right by the deflection yoke 6 before reaching the screen 3 to form a screen.

In this case, the electron beam passes through a plurality of electron beam through holes formed in the shadow mask 4 to reach the screen 3, and in this process, an electron beam not passing through the electron beam through holes passes through the shadow mask 4. As the temperature of the shadow mask 4 is increased, mislanding of the electron beam is caused.

2 is a diagram illustrating a structure of a general shadow mask.

The general shadow mask 4 includes a perforated part 10 in which a plurality of electron beam through holes are formed so that the electron beam emitted from the electron gun 5 can strike the screen 3, and the outside of the perforated part 10. Located at the edge of the non-hole portion 20 is not distributed the electron beam through hole, and the periphery of the non-pore portion 20 is formed to be bent almost perpendicular to the no-hole portion 20, the support frame mask frame and welding fixing 31 Consisting of a skirt portion 30.

The shadow mask 4 undergoes thermal expansion according to the electron beam strike phenomenon. In this case, when the shadow mask 4 causes uniform expansion as a whole, no mislanding phenomenon occurs. However, since the temperature of the shadow mask (4) during the operation of the cathode ray tube is the highest in the center of the hole portion 10, and the lowest at the edge of the skirt portion 30 causes uneven thermal expansion, mis-landing of the electron beam (mislanding) phenomenon occurs.

Therefore, in order to prevent such a phenomenon, the temperature variation of the shadow mask 4 should be minimized. For this purpose, it is preferable to minimize the heat loss of the non-porous portion 20.

3 is a diagram illustrating a combination structure of a typical shadow mask and a mask frame.

As shown in FIG. 3, the combined structure of the general shadow mask 4 and the mask frame 7 is formed so that the end of the mask frame 7 is higher than the position of the bent portion 32 of the shadow mask. As the heat of the skirt portion 30 is transferred to the mask frame 7 by the radiation phenomenon, the temperature deviation between the pore portion 10 and the skirt portion 30 becomes larger.

Therefore, the nonuniform expansion of the shadow mask 4 and the resulting mislanding phenomenon are further intensified.

4 is a diagram illustrating a structure of a shadow mask according to the prior art.                         

The skirt part 30 is a tongue section in which a welding point welded to the mask frame 7 is located in order to minimize the areas of the airless part 20 and the skirt part 30 as a means for solving the above problems. (Not shown) and a tip portion 33 which is bent and extended at the edge of the non-porous portion 20 and has a height lower than that of the tongue piece portion (not shown).

However, in the shadow mask 4 according to the related art, as described above, as the area of the skirt 30 is greatly reduced, the distance DS between the shadow mask 4 and the mask frame 7 increases. do.

5 is a view showing the influence of the magnetic field on the electron beam in the shadow mask and mask frame combination structure according to the prior art, Figure 5a is a cross-sectional view of the upper side of the cathode ray tube, Figure 5b is the cathode ray It is a figure which shows the cross section of the left short side of a pipe | tube.

In the shadow mask according to the related art, as the distance DS between the shadow mask and the mask frame increases, the influence of the geomagnetic field or the external magnetic field on the electron beam penetrating the shadow mask increases, thereby making the electron beam sensitive to the magnetic field. The amount of movement is increased, and thus, the electron beams do not pass through the corresponding electron beam through holes, thereby greatly reducing the color purity of the panel.

That is, when the electron beam passes through the funnel by the deflection magnetic field of the deflection yoke, the inner shield mounted on the mask frame shields the geomagnetic field and the external cradle to prevent movement of the electron beam.                         

However, when the electron beam reaches the panel through the electron beam through hole of the shadow mask, the electron beam is affected by a geomagnetic field or a local external magnetic field due to the distance between the shadow mask and the mask frame. Variable. At this time, the force for varying the path of the electron beam is defined by the following equation as the Lorentz force.

F = qV X B

(F: Lorentz force, q: amount of particles charged, V: speed of charged particles, B: magnetic flux density through which charged particles pass)

In addition, in general, when a magnetic body whose movement is variable by a geomagnetism or an external magnetic field is placed in an external magnetic field, a magnetic field is formed in a direction opposite to the external magnetic field to make the inside of the cathode ray tube non-magnetic, and the inside of the cathode ray tube is completely spherical. The path distortion of the electron beam is inevitably generated because it is not formed as a closed curve of and because a plurality of components mounted inside the cathode ray tube are also magnetized in the geomagnetic direction.

Table 1 shows the amount of movement of the electron beam generated when the direction change by the geomagnetic field of the shadow mask having a tip portion and the shadow mask having no tip portion in order to minimize the area of the skirt portion, and the shadow mask and the mask frame As the distance increases, the amount of movement of the electron beam due to a geomagnetic field increases, which causes a problem of deterioration of color purity of the panel.

Diagonal dimensions (mm) Skirt tip DS (mm) The amount of electron beam movement due to the change of direction of the geomagnetic field (㎛) East-> West South-> North 68 radish 0 30 30 radish 35 45 45 U 70 55 55

In particular, when a plurality of holes are formed in the tip portion in order to minimize the area of the skirt portion, the amount of electron beams exposed to the magnetic field is further increased to increase the amount of movement of the electron beams and to worsen the color purity degradation of the panel. do.

The present invention has been made to solve the above-described problems of the prior art, in the shadow mask formed with a minimum area to prevent thermal expansion of the shadow mask and the resulting mis-landing phenomenon, the mask frame for supporting the shadow mask It is an object of the present invention to provide a mask frame that prevents color purity degradation caused by increasing an interval between the shadow mask and the mask frame by attaching the beads.

The mask frame according to the present invention for solving the above problems is to support a shadow mask provided with a hole having a plurality of electron beam through holes, a hole is located at the outer edge of the hole and a tip extending vertically from the hole In the mask frame is welded and fixed to the shadow mask, the mask frame is characterized in that it comprises a bead protruding toward the tip end portion formed to face the tip end portion.

In addition, the mask is welded and fixed to the shadow mask to support the shadow mask is provided with a hole having a plurality of electron beam through-holes, a hole is located at the outer edge of the hole and the tip portion is bent vertically extending from the hole The frame is characterized in that the mask frame is formed to protrude toward the tip end portion, and includes a bead whose tip is formed lower than the tip end portion.

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

The color cathode ray tube according to the present invention comprises a panel and a funnel bonded to the panel to form a vacuum container. A phosphor screen coated with three phosphors emitting blue, green, and red light is formed on an inner surface of the panel, and a rectangular shadow mask spaced apart from the screen by a predetermined interval is mounted inside the phosphor screen.

The neck of the funnel is equipped with an electron gun that emits three electron beams, and a deflection yoke mounted on an outer side of the funnel to deflect the electron beam emitted from the electron gun up, down, left, and right, and the electron beam emitted from the electron gun is It is deflected by the deflection yoke and strikes the phosphor of the screen through the shadow mask to display an image.

 6 is a diagram illustrating a structure of a shadow mask according to the present invention.

The shadow mask 50 according to the present invention includes a hole having a plurality of electron beam through-holes, a non-hole positioned at an outer edge of the hole, and vertically bent from an outer edge of the non-porous portion of the shadow mask 50. It is composed of a skirt portion connected to the mask frame for supporting).

In addition, the skirt portion may be composed of a tongue section where the welding point is welded and fixed to the mask frame, and a tip end portion other than the tongue section.

The tip portion may be formed to have the same length as the tongue piece portion, and may be formed to have a height lower than that of the tongue piece portion in order to prevent a mislanding phenomenon caused by thermal expansion of the shadow mask.

At this time, when the height Mn of the tip portion is formed lower than the height Sh of the tongue section as described above, it is preferable to satisfy the following relational expression.

Mn <1/2 X Sh

In addition, a plurality of holes may be formed in the front end portion to more effectively prevent mis-landing, and the shadow mask may be formed of an AK material as well as an invar material.

In the present invention, it is specified that the application is applicable to all of the shadow mask implemented in the above form.

FIG. 7 is a perspective view illustrating a shadow mask and a mask frame coupling structure according to the present invention, and FIG. 8 is a view showing the structure of a mask frame according to the first embodiment of the present invention in detail.

The mask frame 60 according to the present invention is fixed to the skirt portions 51 and 52 of the shadow mask 50 to support the shadow mask 50.

The mask frame 60 is formed in a rectangular shape having a cross-sectional L-shape, and protruding portions are formed at each side edge of the mask frame 60 to be welded to the shadow mask tongue 51.

At this time, the mask frame 60 according to the present invention is configured to include a bead 61 formed to protrude toward the front end portion 52 along each side to face the front end portion 52.

The bead 61 mounted on the mask frame 60 may be implemented in various shapes, and the beads 61 may be implemented in three shapes in the present specification.

That is, the bead 61a may be formed in an L shape toward the distal end portion 52 of the shadow mask so that the long side of the L-shaped beads 61a faces the distal end portion 52.

In addition, the bead 61b may be formed to have a concave-convex shape to face the distal end portion 52, and may be formed to have a predetermined angle θ toward the distal end portion.

In this case, when the bead 61c is formed to be inclined with a predetermined angle θ, the angle θ is preferably formed to satisfy a range of 15 ° to 30 °.

On the other hand, it is preferable that the width of the bead 61 according to the present invention is 0.5mm or more.

In addition, the bead 61 is a gap DS between the mask frame 60 and the shadow mask 50, the width FS of the bead, the length Mw of the tip portion, the length Fw of the bead, It is preferable that the height Fsh of the bead and the height Fsi of the mask frame satisfy the following relational expression.

FS / DS ≥ 10%

Fw / Mw ≥ 10%

Fsh <Fsi

Table 2 is a table showing the amount of electron beam movement according to the distance between the mask frame 60 and the tip 52, the bead 61 is formed.

That is, when comparing Table 1 according to the prior art and Table 2 according to the present invention, the shadow mask 50 and the mask frame generated due to the reduction of the area of the shadow mask skirt portion facing the mask frame 60. An increase in the interval DS between 60 can be reduced through the bead 61 formed in the direction of the tip portion 52, so that the influence of the electron beam by the geomagnetic field can be reduced.

Diagonal dimensions (mm) DS (mm) Amount of Electron Beam Movement According to Direction Change of Geomagnetic Field (㎛) East-> West South-> North 68 70 57 57 35 47 47 0 32 32

Diagonal dimensions (mm) DS (mm) Howling Frame strength 68 70 X △ 35 △ ○ 0 ○ ◎

In addition, as shown in Table 3, as the bead 61 is formed in the mask frame 60 and the width of the bead 61 is increased to decrease the gap DS, the mask frame against external impact The strength of 60 can be increased, and the howling properties can also be improved.

9 is a diagram showing the structure of a mask frame according to a second embodiment of the present invention. Since the mask frame 60 according to the second embodiment of the present invention has a similar configuration except for the beads 61d, additional description thereof will be omitted.                     

That is, the mask frame 60 includes a bead 61d protruding toward the distal end portion 52, and the end of the bead 61d is lower than the distal end portion 54 of the distal end portion.

Therefore, the shape of the bead 61d implemented through the second embodiment of the present invention may be applied to all of the shapes illustrated in the first embodiment when the end thereof is formed lower than the end 54 of the tip portion. have.

As described above, the mask frame according to the present invention has been described with reference to the illustrated drawings. However, the present invention is not limited by the embodiments and drawings disclosed herein, and the mask is used to reduce the amount of electron beam movement by a geomagnetic field or an external magnetic field. The idea of mounting a bead to a frame can be readily applied by one skilled in the art within the scope of protection.

The mask frame according to the present invention configured as described above can be greatly reduced the effect of the geomagnetic field or external magnetic field caused by the increase in the gap by mounting a variety of beads to reduce the distance to the shadow mask, The strength of the frame is increased to improve durability, and howling properties may also be improved, thereby greatly improving the reliability of the product.

Claims (14)

In the mask frame welded and fixed to the shadow mask to support a shadow mask having a hole having a plurality of electron beam through holes, a non-hole located at the outer edge of the hole and a tip portion extending vertically from the non-hole; The mask frame is characterized in that it comprises a bead protruding toward the tip end portion to face the tip end portion. In the mask frame welded and fixed to the shadow mask to support a shadow mask having a hole formed with a plurality of electron beam through holes, a hole portion located at the outer edge of the hole portion and a tip portion extending vertically bent from the hole portion In The mask frame is protruding toward the tip side, the mask frame characterized in that it comprises a bead is formed lower than the tip end. The method according to claim 1 or 2, The front end portion is a mask frame, characterized in that a plurality of holes are formed. The method according to claim 1 or 2, The shadow mask is a mask frame, characterized in that formed of AK material. The method according to claim 1 or 2, The bead mask frame, characterized in that formed in the L-shape toward the front end of the shadow mask. The method according to claim 1 or 2, The bead is mask frame, characterized in that formed in the concave-convex shape toward the leading end of the shadow mask. The method according to claim 1 or 2, The bead mask frame, characterized in that formed to be inclined at a predetermined angle toward the tip side of the shadow mask. The method of claim 7, wherein The bead mask frame, characterized in that formed to be inclined at an angle of 15 ° to 30 °. The method according to claim 1 or 2, The bead is a mask frame, characterized in that the width is formed to more than 0.5mm. The method according to claim 1 or 2, And the bead is formed such that the interval DS between the mask frame and the shadow mask and the width FS of the bead satisfy the following relational expression. FS / DS ≥ 10% The method according to claim 1 or 2, And the bead is formed such that the length (Mw) of the tip portion and the length (Fw) of the bead satisfy the following relational expression. Fw / Mw ≥ 10% The method according to claim 1 or 2, The bead mask frame, characterized in that the height (Fsh) and the height (Fsi) of the frame satisfy the following relationship. Fsh <Fsi The method according to claim 1 or 2, The shadow mask includes a tongue section in which a welding point is welded to the mask frame, wherein the tongue section has a height greater than that of the tip end portion. The method of claim 13, The shadow mask is a mask frame, characterized in that the height (Sh) of the tongue section and the height (Mn) of the tip portion satisfy the following relational expression. Mn <1/2 X Sh

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