Frame for cathode ray tube having a plurality of beads

1. A frame for a cathode ray tube comprising a substantially rectangular frame body having longer and shorter sides, and one or more beads formed on each of the longer frame sides, and one or more beads formed on each of the shorter frame sides,

wherein the beads formed on each longer frame side are arranged such that one bead is arranged at a central portion of the longer frame side, and two beads are arranged at opposite sides of the central portion of the longer frame side respectively, and;

at least one of the beads formed on each of the longer frame sides has a shape different from a shape of the beads formed on each of the shorter frame sides, to increase a rigidity of the longer frame side, and the at least one bead of each longer frame side is a stepped bead having a structure having a plurality of portions with different heights.

2. The frame according to claim 1 , wherein the beads arranged at the opposite sides of the central portion of each longer frame side are stepped beads, respectively.

3. The frame according to claim 2 , wherein the frame satisfies the following conditions:

L

>

H

+

V

V1

,

and

⁢

⁢

V2

<

3

2

*

V1

where, “H” represents a distance from a center of an opening defined by a bottom wall of the frame to a peripheral edge of the opening along a longer axis in each stepped bead, “V” represents a distance from the center to the peripheral edge of the opening along a shorter axis, “L” represents a whole length of each stepped bead, “V 1 ” represents a height of the first layer of each stepped bead, and “V 2 ” represents a height of the second layer of each stepped bead.

4. The frame according to claim 3 , wherein the height of the first layer of each stepped bead satisfies a condition of “5 mm≦V 1 ≦15 mm”.

5. The frame according to claim 3 , wherein the frame satisfies the following condition:

I

>

(

L

+

H

)

*

V1

2

*

V2

where, “I” represents a distance from a center of each longer frame side to a leading end of each stepped bead arranged toward the longer frame side center.

6. The frame according to claim 2 , wherein the frame satisfies the following conditions:

d

>

3

2

*

s

,

and

⁢

⁢

w

>

1

3

*

u

where, “s” represents a length of the first layer of each stepped bead, “d” represents a length of the second layer of each stepped bead, “u” represents a width of the bottom wall of the frame, and “w” represents a width of each stepped bead.

7. The frame according to claim 6 , wherein the frame satisfies the following condition:

8 mm<w<t

where, “t” represents a width of the bead formed at the central portion of each longer frame side.

8. The frame according to claim 1 , wherein the frame has a thickness of 0.2 mm to 0.8 mm.

9. The frame according to claim 1 , wherein the stepped bead of each longer frame side comprises two layers.

10. A frame for a cathode ray tube comprising a substantially rectangular frame body having longer and shorter sides, and one or more beads formed on each of the longer frame sides, and one or more beads formed on each of the shorter frame sides,

wherein the beads formed on each longer frame side are arranged such that one bead is arranged at a central portion of the longer frame side, and two beads are arranged at opposite sides of the central portion of the longer frame side, respectively, and;

the number of the beads formed on each of the longer frame sides is different from the number of the beads formed on each of the shorter frame sides, to increase a rigidity of the longer frame side, and at least one bead of each longer frame side is a stepped bead having a structure having a plurality of portions with different heights, and.

11. The frame according to claim 10 , wherein the number of the beads formed on each longer frame side is greater than the number of the beads formed on each shorter frame side.

12. The frame according to claim 11 , wherein the at least one bead of each longer frame side has a shape different from a shape of the beads formed on each shorter frame side.

13. The frame according to claim 10 , wherein the beads arranged at the opposite sides of the central portion of each longer frame side are stepped beads, respectively.

14. The frame according to claim 10 , wherein the frame has a thickness of 0.2 mm to 0.8 mm.

15. The frame according to claim 10 , wherein the stepped bead of each longer frame side comprises two layers.