KR20000031565A - Structure of frame for cathode ray tube - Google Patents

Abstract

PURPOSE: A frame for a cathode ray tube is provided to improve a howling due to the delivery of an exterior vibration and the amount of shock through the frame to a shadow mask due to the increase of natural vibration number in the frame. CONSTITUTION: A howling is improved by using the difference in characteristic according to the length and shortness of a bead(14) formed at a corner in a structure. Herein, the structure reduces howling by increasing rigidity by forming the bead in a specific width and a depth at each corner of a frame(7). In the frame, C is a length of the bead of the corner, and B is 1/4 of the length of an outer circumference of the frame. D is the height of the frame, while d is the height of the bead of the frame. And, W1 is the length of a flange of a corner of a long side, then W2 is the length of a flange in the corner at a short side. Wv is the depth of the bead at the long side, Wh is the depth of the bead at the short side, while C is the same or more than BX1/2. Then, d is the same of more than 1/6XD and the same or less than 1/2XD, and Wv is the same or more than 1/6XW1 and the same or less than 1/2XW1. Then, Wh is the same or more than 1/6XW2 and the same or less than 1/2XW2. Moreover, the length(4C) of a whole beads of the corner is longer than the one of the length(A) of the outer circumference of the frame by 2/3.

Description

Frame structure for cathode ray tube

The present invention relates to a color cathode ray tube, and more particularly, to a structure of a frame in which a shadow mask, which serves as color selection, is fixed.

FIG. 1 is a side view showing a general color cathode ray tube in a partial cross-section, in which red, green, and blue phosphors are applied to an inner surface of a panel 1 to form a fluorescent film 2, and a neck behind the panel 1 is a neck. The funnel 3 in which the electron gun 4 is enclosed in the part 3a is fused by glass.

The shadow mask 6, which serves as color screening of the electron beam 5 emitted from the electron gun 4, is fixed to the frame 7 at a portion adjacent to the fluorescent film 2 coated on the inner surface of the panel 1. The frame 7 is inserted into the stud pin 9 fixed to the side wall of the panel 1 by a spring 8 fixed to the frame to maintain the suspended state.

In addition, an inner shield 10 is provided on one side of the frame 7 to protect the electron beam 5 moving to the fluorescent film 2 side from an external geomagnetic field during operation of the cathode ray tube by the fixing spring 11. A reinforcing band 12 is wound around the outer circumferential surface of the cathode ray tube to prevent firecrackers from external impact during operation of the cathode ray tube.

The inner and outer surfaces of the funnel 3 are coated with internal and external graphite (not shown), and the trajectory of the funnel 3 is modified so that the electron beam 5 strikes a predetermined phosphor exactly on the outer circumferential surface of the neck portion 3a. 2, 4 and 6 pole magnets 13 are provided.

The shadow mask 6, which is fixed to the frame 7 and serves as color selection of the electron beam 5, is molded into a press die and then welded and fixed to the frame 7 so as to maintain the formed curvature in a designed dimension. You will build an assembly.

The shadow mask assembly thus constructed is supported by the stud pins 9 of the panel 1 with a spring 8 to form a geometric structure with the panel 1 so that the three electron beams 5 radiated from the electron gun 4 can be seen in the panel ( The screen is reproduced because the phosphor formed on the inner surface of 1) is precisely hit.

The interval (array) of the electron beam, which is a grouping rate formed on the fluorescent surface, may be expressed by the following equation.

Beam Grouping Rate = (3 × S × Q) / (Ph × L)

Where S: deflection yoke component

Q: Distance from the shadow mask slot to the inner surface of the panel

Ph: Distance between shadow mask slot centers

L: The distance from the deflection yoke's electron beam deflection center to the inner surface of the panel.

In the above formula, the arrangement (G / R) of the target electron beam is typically designed to be 1.000.

Here, "S" is a plane perpendicular to the electron beam at the point where the electron beam strikes, and G electron beam and R and R electron beam in the electron gun as one plane, and G electron beam and R when the two planes are parallel planes. , B means the distance of the electron beam. If the deflection yoke is designed, "S" may be regarded as a constant.

And when designing G / R by grouping or de-grouping according to designer's design concept, appropriate G / R is designed while changing Q and Ph.

According to the above equation, if the distance Q between the shadow mask 6 and the inner surface of the panel 1 is large or small, the electron beam arrangement is unbalanced, which adversely affects the color purity.

In addition, the inner shield 10 is fixed to the frame 7 to which the shadow mask 6 is fixed by a fixing spring 11 to shield the geomagnetic field that can change the path of the electron beam during operation of the cathode ray tube. The phenomenon of deterioration is prevented.

Meanwhile, when the cathode ray tube is operated, when the electron beam radiated from the electron gun 4 strikes the phosphor through the slot of the shadow mask 6 as shown in FIG. 3, most of the electron beams 5 hit the shadow mask and generate heat energy. As a result, the domming phenomenon of thermal expansion of the shadow mask is caused, and thus the position of the slots formed in the shadow mask 6 is varied because the frame 7 is secondly thermally expanded.

In addition, when the cathode ray tube is operated, vibration caused by speaker sound or external shock is transmitted to the frame 7 through the panel 1 and the stud pins 9 attached to the panel, so that the vibration is shaken when the frame 7 is shaken. Since the shadow mask is transmitted to the mask 6 and causes a howling phenomenon in which the shadow mask vibrates, the screen is shaken.

Accordingly, in the related art, beads 14 having various shapes are formed in the frame as shown in FIGS. 4A to 4C to improve the howling phenomenon and the drop impact characteristics by increasing the rigidity of the frame 7.

4A is a technique shown in Korean Patent Laid-Open Publication No. 97-8273, in which a bead 14 having a predetermined depth and width is formed at an edge of a frame 7, which is the most fundamental structure through vibration analysis.

FIG. 4B is a structure that increases rigidity than the bead shape of FIG. 4A. The bead 14 further includes a long side, a short side, and a stepped portion in the corner portion of the frame 7.

4C shows the rigidity of the frame 7 by changing the length of the beads formed on the long side and the short side, the bead width, the height of the bead, the long side length of the corner bead, the short side length of the corner bead, the width of the corner bead, and the like. It is a structure to increase.

However, since the bead 14 of various shapes and number has a large number of peak frequencies in a predetermined frequency (300 Hz or less) range, the howling characteristic cannot be improved.

That is, as shown in FIGS. 9A and 9B, since the number of the natural frequencies (peak frequencies) is generated in the region below 300 Hz where the howling phenomenon occurs, the result is not good.

In addition, when the radius of curvature of the shadow mask 6 is large, considering only the stiffness of the frame 7, external physical force (vibration or impact) is directly transmitted to the frame in the shadow mask assembly structure to increase the howling phenomenon. May result.

The present invention has been made to solve such a problem in the prior art, the purpose of improving the howling phenomenon caused by increasing the natural frequency of the frame is transmitted to the shadow mask through the external vibration and shock through the frame.

According to an aspect of the present invention for achieving the above object, in a frame in which a shadow mask assembly is beaded at a predetermined depth and width in a corner portion in a cathode ray tube fitted to a stud pin attached to a panel, C: bead length of a corner portion , B: 1/4 of frame outer circumference length, D: frame height, d: frame bead height, W1: long side corner flange length, W2: short side corner flange length, Wv: long side bead depth, Wh: short side Speaking of the bead depth, C ≥ B × 1/2, 1/6 × D ≤ d ≤ 1/2 × D, 1/6 × W1 ≤ Wv ≤ 1/2 × W1, 1/6 × W2 ≤ Wh Provided is a frame structure for a cathode ray tube, characterized by consisting of ≦ ½ × W 2.

Figure 1 is a side view showing a typical color cathode ray tube in some cross section

2 is a diagram for explaining a beam grouping rate.

3 is a view for explaining a heat transfer order according to the electron beam hit the shadow mask.

4 is a perspective view showing a conventional frame structure

5 is a perspective view of a frame showing one embodiment of the present invention;

6 is a front view of FIG. 5

7 is a front view of a frame illustrating another embodiment of the present invention.

8 is a cross-sectional view taken along the line A-A of FIG. 6 showing another embodiment of the bead shape

9A to 9C are graphs showing a comparison between the present invention and the prior art.

Explanation of symbols for main parts of the drawings

1 panel 6: shadow mask

7: frame 14: bead

Hereinafter, with reference to Figures 5 and 9 showing the present invention as an embodiment as follows.

5 is a perspective view of a frame showing one embodiment of the present invention, FIG. 6 is a front view of FIG. 5, and FIG. 7 is a front view of a frame showing another embodiment of the present invention.

According to the present invention, the bead length is formed in the corner portion of the frame 7 in the structure of reducing the howling phenomenon by increasing the rigidity by forming the beads 14 at a predetermined depth and width. The howling phenomenon is improved by using the characteristic difference.

The relationship between the length of the bead 14 formed at the corner of the frame 7 and the natural frequency is expressed as follows.

Where ω is the natural frequency of the frame

k: rigidity of the frame

ρ: density (frame mass)

E: modulus of elasticity

I: moment of inertia

ℓ: frame length.

According to the above equation, it can be seen that increasing the rigidity of the frame 7 increases the natural frequency proportionally.

That is, when the moment of inertia is increased in the structure of the frame having the same material, the same length, and the same modulus of elasticity, the rigidity is increased and the natural frequency is also increased.

Therefore, successively forming the beads 14 in the structure of the frame 7 having a certain length to increase the moment of inertia, which is a property of resisting deformation, has a large moment of inertia, thereby increasing the natural frequency.

That is, it is defined as natural frequency (ω) 모 moment of inertia (I).

In addition, in the structure of the frame having a certain length, the displacement caused by the vibration is the largest in the center portion of each side.

Therefore, in the bead configuration in which the moment of inertia is raised for a certain length in order to increase the rigidity of the central portion, the moment of inertia rises continuously if the length of the formation portion of the bead 14 is relatively longer than the portion where no beads are formed. It has a howling characteristic similar to the formed bead effect.

In addition, when the bead 14 is provided in the corner portion at least 2/3 of the frame length, the vibration displacement of the central portion due to the vibration can be reduced to the maximum.

In more detail, since the spring 8 for supporting the frame assembly to the stud pin 9 of the panel 1 is welded to the long and short side portions of the frame 7, If the bead 14 is formed to be 2/3 or more of the frame length, the moment of inertia is increased to increase the rigidity, and the natural frequency of the vibration primary mode is also increased, and the peak frequency that causes howling in a certain frequency range is increased. Since it is possible to reduce the howling characteristics of the cathode ray tube can be improved.

The configuration of the present invention with respect to the corner bead length as shown in Figure 6 to form a bead 14 stepped to a predetermined depth and width at each corner portion of the frame 7 to improve the rigidity by improving the rigidity In the reducing structure, when viewed from the left and right, top and bottom symmetrical structure of the frame having the staircase or "a" shaped corner bead 14 on the long side and the short side,

Frame outer circumference length: A

1/4 of frame perimeter circumference: B

Corner stepped or "ㄱ" bead length: C

1/2 of long side frame length: H / 2

1/2 of short side frame length: V / 2

Long side bead length: C1

Short side bead length: at C2

When the bead 14 is formed such that the corner bead length C has a condition of C ≧ B × 1/2, the rigidity of the frame is increased and the natural frequency is increased, thereby reducing the howling.

In particular, if the conditions are formed such that C1? H / 4 and C2? V / 4, the howling characteristics can be further improved.

In addition, the bead height (d) is, as shown in FIG.

Frame height: D

Frame bead height: at d

When the bead height is formed under the condition of 1/6 × D ≦ d ≦ 1/2 × D, the stiffness is greatest.

If the height (d) of the bead 14 is set to more than half (1/2) of the frame height (D), the thickness of the edge of the bead (14) is thin, the rigidity of the frame is weakened, causing severe distortion of the frame Therefore, more than half should be set.

On the contrary, when the bead height is formed to be 1/6 or less of the frame height D, the effect of the formation of the beads 14 is not effective, and thus, the torsion occurs in the frame, and thus the rigidity is weakened. The effect of the improvement can be obtained.

When the height d of the bead 14 is formed under the condition of 1/6 × D ≦ d ≦ 1/2 × D, setting the range of C1 > H / 3 and C2 > It is more effective in increasing the stiffness.

On the other hand, the depths Wv and Wh of the beads 14 are as shown in FIG. 5,

Long Edge Corner Flange Length: W1

Short Edge Corner Flange Length: W2

Long side bead depth: Wv

Short side bead depth: Wh

The long side bead depth Wv is set to 1/6 × W1 ≦ Wv ≦ 1/2 × W1, and the short side bead depth Wh is set to 1/6 × W2 ≦ Wh ≦ 1/2 × W2.

When the depths Wv and Wh of the beads 14 are also set to 1/2 or more of the flange length or 1/6 or less, similarly to the height d, the effect due to the formation of the beads is reduced, so that the rigidity is inferior.

The bead 14 has a shape of “a” as shown in FIGS. 5 and 6, and an arc shaped curve as shown in FIG. 8 shown in another embodiment to increase rigidity. Being able to do it is understandable.

As described above, in the present invention, the corner beads are formed longer than before, thereby increasing the rigidity of the frame and simultaneously forming the corner beads, thereby increasing the cross-sectional moment of inertia, thereby maximizing the effect of forming the beads. .

Also, by increasing the length of the corner bead relative to the portion without the bead, the howling frequency is shifted toward a larger size than the conventional one, so that the peak frequency causing howling is less than that shown in FIGS. 9A and 9B, as shown in FIG. 9C. The effect is that the characteristics are improved.

Claims (8)

In a frame in which a shadow mask assembly is beaded at a predetermined depth and width at a corner of a cathode ray tube fitted to a stud pin attached to a panel, C: bead length at a corner portion, B: 1/4 of a frame outer circumference length, D : Frame height, d: frame bead height, W1: long side corner flange length, W2: short side corner flange length, Wv: long side bead depth, Wh: short side bead depth, C ≥ B × 1/2 And 1/6 × D ≦ d ≦ 1/2 × D, 1/6 × W1 ≦ Wv ≦ 1/2 × W1, 1/6 × W2 ≦ Wh ≦ 1/2 × W2 Tolerance frame structure. The method of claim 1, A frame structure for cathode ray tubes, wherein the total bead length 4C of the corner portion is set to be larger than 2/3 of the outer circumferential length A of the frame. The method of claim 1, Corner bead depths Wh and Wv of the frame are set to be 1/6 to 1/2 or less of the long and short side flange lengths W1 and W2, and the height d of the beads is 1 of the frame height D. Frame structure for cathode ray tube, characterized in that set to / 6 ~ 1/2 or less. The method of claim 1, Frame structure gun for cathode ray tube, characterized in that the cross section of the corner bead "" shaped. The method of claim 1, A frame structure for a cathode ray tube, characterized in that the cross section of the corner bead is made of an arc-shaped curved surface. The method of claim 1, C1: long side bead length, C2: short side bead length, H: long side length, V: short side length, C1 > H / 4, C2 > The method of claim 1, Frame structure for a cathode ray tube, characterized in that the beads are integrally formed over the entire frame. The method of claim 3, wherein C1: long side bead length, C2: short side bead length, H: long side length, V: short side length, C1 > H / 3, C2 >