KR20030075781A - Cathode ray tube having shield member which reduces effect of external magnetism - Google Patents

Abstract

PURPOSE: A cathode ray tube is provided to achieve improved color purity characteristics by reducing mis-landing of electron beams caused due to the terrestrial magnetism. CONSTITUTION: A cathode ray tube comprises a panel(20) having a screen portion(20a) where a phosphor screen(22) is formed and a side surface(20b) formed along the circumference of the screen portion; a funnel(24) connected to the panel, and which has an outer surface on which a deflection unit(28) is mounted; a neck(26) connected to the funnel, and which has an inside where an electron gun(30) for emitting electron beams is mounted; a color discrimination unit(32) mounted at the inside of the panel, and which discriminates colors of electron beams and permits electron beams to reach the corresponding phosphors of the phosphor screen; and a shield member(40) connected to the color discrimination unit and disposed toward the neck so as to shield a terrestrial magnetism affecting the electron beam scanning orbit. The shield member has a center slot(40c) formed at the center of a longer side(40a) in such a manner that the center slot is parallel to the electron beam advancing path. The shield member has side slots(40d) which are shorter than the center slot and inclined toward the panel.

Description

Cathode ray tube with shield member to reduce the influence of external magnetism {CATHODE RAY TUBE HAVING SHIELD MEMBER WHICH REDUCES EFFECT OF EXTERNAL MAGNETISM}

The present invention relates to a cathode ray tube, and more particularly, to a cathode ray tube provided with a shield member to prevent the electron beam scanned from the electron gun to the fluorescent screen from being miss landing under the influence of geomagnetism.

Cathode ray tubes, which are widely used in color televisions, computer monitors, and the like, in an image display device, realize a predetermined image by scanning an electron beam generated from an electron gun onto a fluorescent screen coated with R, G, and B phosphors.

At this time, the electron beam should be scanned not only at the center portion of the fluorescent screen having a substantially rectangular shape but also at its periphery to emit phosphors applied to the portion, and when it is scanned at the periphery, it will be deflected by the magnetic field formed from the deflecting device. The desired phosphor position is reached.

However, when the electron beam is affected by a magnetic field acting outside the cathode ray tube, for example, geomagnetism, in the scanning process of the electron beam, the so-called mislanding phenomenon that the phosphor does not reach the phosphor to be finally reached but reaches another phosphor. To deteriorate the color purity characteristics of the cathode ray tube.

Looking at the mis-landing phenomenon of the electron beam in more detail, first, the electron beam scanned from the electron gun receives a Lorentz force while traveling toward the fluorescent screen inside the cathode ray tube, and its path is changed. For example, when an electron beam moves in a vertical direction (Y direction) of the fluorescent screen in a cathode ray tube in which the phosphor forming the fluorescent screen is a stripe type, the electron beam emits phosphors of the same color, so color purity problems do not occur. When the electron beam moves in the horizontal direction (X direction) of the fluorescent screen, the moved electron beam emits phosphors of different colors, causing color purity problems.

The horizontal component (X direction) component F _x of the Lorentz force causing the color purity problem is represented by Equation 1 below.

Where e is the amount of charge, v is the speed of the electron beam, B is the magnetic flux density, and the subscripts x, y and z represent the X, Y and Z directions, respectively.

In addition, the geomagnetic component affecting the cathode ray tube may be divided into a vertical component in a direction perpendicular to the ground (Y direction) and a horizontal component in a direction horizontal to the ground. The subdivision of the horizontal component of the geomagnetic field acts as an early north-south direction (hereinafter referred to as NS direction) horizontal component acting in parallel with the tube axis of the cathode ray tube (hereinafter referred to as NS direction) and perpendicular to the tube axis (X direction). It can be classified into the so-called east-west direction (hereinafter referred to as EW direction) horizontal component.

In the conventional cathode ray tube, an inner shield, which is a magnetic shield member, is mounted on an assembly of a shadow mask and a mask frame so that the electron beam is not affected by the geomagnetism, and is mounted inside the cathode ray tube. In order to minimize the mis-landing phenomenon, a V-shaped notch is formed at the short side of the inner shield, or as shown in FIG. 12 or 13, the electron beams are formed at the long sides 60a and 64a of the inner shield 60 and 64. Long single or plurality of slots 60b and 64b are formed in parallel with the scanning direction.

However, the inner shields 60 and 64 having slots of such a shape mainly aim to reduce the mislanding amount of the electron beam due to the horizontal component of the EW direction of the geomagnetic field. There was a problem that the amount of landing rather increased.

The present invention has been made to solve the above problems, the object of which is to minimize the influence of the horizontal magnetic force in the external magnetic field, such as geomagnetic field, in particular the tube axis direction (NS direction) to reduce the amount of mis-landing of the electron beam It is to provide a cathode ray tube having a shield member.

1 is a cross-sectional view showing a cathode ray tube having a shield member according to the present invention.

2 is a perspective view showing a shield member according to an embodiment of the present invention.

3 is a front view showing a shield member according to an embodiment of the present invention.

4 is a front view showing a shield member according to a second embodiment of the present invention.

5 is a front view showing a shield member according to a third embodiment of the present invention.

6 is a front view showing a shield member according to a fourth embodiment of the present invention.

7 is a cross-sectional view for explaining a process of changing the magnetic field by the side slot of the shield member according to the present invention.

8 is a graph showing the distribution of the spatial magnetic field along the path of the electron beam in the cathode ray tube according to the present invention.

9 is a graph showing the relationship between the neck end position h of the lateral slot and the electron beam movement amount at the diagonal point according to the present invention.

10 is a graph showing the relationship between the distance (w) between the lateral slots symmetrical and the electron beam movement amount according to the present invention.

11 is a graph showing the relationship between the short side length L of the lateral slots and the electron beam movement amount according to the present invention.

12 is a front view showing a conventional shield member.

13 is a front view showing a conventional shield member.

* Description of the symbols for the main parts of the drawings *

20: Panel 20a: Screen portion

22: fluorescent screen 24: funnel

26: Neck 28: Deflection Device

30: electron gun 31: electron beam

32: color screening device 33: magnetic field

34: mask 36: frame

40: shield member 40a: long side portion

40b: short side 40c: center slot

40d: side slot

In order to achieve the above object, the present invention includes a panel having a screen portion on which a fluorescent screen is formed, and a side surface formed around the screen portion; A funnel connected to the panel and provided with a deflection device on an outer circumference thereof; A neck connected to the funnel and equipped with an electron gun for generating an electron beam scanned into the fluorescent screen therein; A color sorting apparatus mounted inside the panel to color-select the electron beam to reach a corresponding phosphor of the fluorescent screen; And a shield member arranged to be connected to the neck while being connected to the color screening device to shield the geomagnetism which affects the scanning trajectory of the electron beam, wherein the shield member is centered in a long side parallel to the path of the electron beam. A slot is formed, and on the left and right sides of the center slot, a side slot shorter than the length of the center slot is biased toward the panel to provide a cathode ray tube formed parallel to the path of the electron beam.

The side slots are preferably formed to be symmetrical with respect to the center axis of the cathode ray tube (Z direction), the length of the panel side of the shield member W, between the panel end of the side slots symmetrical to each other When the distance is w, the shield member may be formed by satisfying the following equation.

40 ≤ (w / W) × 100 ≤60

In addition, the width of the shield member in the tube axis direction (Z direction) of the cathode ray tube is H, and the distance from the panel side of the shield member in the tube axis direction (Z direction) to the neck end of the side slot is h. When doing so, the shield member may be formed by satisfying the following equation,

15 ≤ (h / H) x 100 ≤ 60,

When the long side length of the panel side of the shield member is W and the short side length of the side slot is L, the shield member may be formed by satisfying the following equation.

1 ≤ (L / W) × 100 ≤7

On the other hand, the color screening apparatus in the cathode ray tube comprises a mask having a plurality of electron beam through holes and the shape of the major axis and the minor axis is set; And a pair of support members disposed to correspond to the major axis of the mask at predetermined intervals and coupled to the mask stretched in one of the major and minor axes, and arranged to correspond to the minor axis of the mask. It may also be configured to include a frame composed of a pair of rigid members fixed across both ends of the support members to maintain the tension applied to the mask.

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

1 is a cross-sectional view showing a cathode ray tube having a shield member according to the present invention, Figure 2 is a perspective view showing a shield member according to an embodiment of the present invention.

As shown in FIG. 1, the cathode ray tube according to the present invention includes a panel 20 that forms a fluorescent screen 22 on an inner surface of the screen portion 20a and forms a side surface 20b around the screen portion 20a. And form an external appearance with a vacuum tube formed of a funnel 24 connected to the panel 20 and a neck 26 connected to the funnel 24, and the electron beam is formed on the outer circumference of the funnel 24 as usual. The deflecting device 28 for deflecting the laser beam is mounted and the electron gun 30 for generating the electron beam is mounted inside the neck 26.

In addition, a color screening device 32 for color-selecting a plurality of R, G, and B electron beams scanned by the electron gun 30 is mounted inside the panel 20. The mask 34 included in the color screening device 32 is formed of a tension mask type. That is, the mask 34 has a substantially rectangular shape in which a long axis and a short axis are set while having a plurality of electron beam through holes.

The mask 34 is fixed to the frame 36 that is tensioned and supported by the predetermined tension in the long axis or short axis direction, wherein the frame 36 is a support member disposed to face each other at a predetermined interval from each other And a rigid member 36b fixedly coupled to both ends of the support members 36a to form a rectangular frame together with the support members 36a.

The color screening device 32 configured as described above is disposed inside the panel 20 so that the mask 34 faces the fluorescent screen 22 and is substantially connected to the panel by a coupling means composed of a hook and a spring. 20) It is mounted inside.

On the other hand, the color screening device 32 is coupled to the periphery of the frame 36 in the direction toward the neck 26 and disposed in a space between the panel 20 and the neck 26 to scan the trajectory of the electron beam. Shield member 40 for shielding the geomagnetism affecting is installed.

As shown in FIG. 2, the shield member 40 is composed of a combination of a pair of long side portions 40a and short side portions 40b facing each other, where the long side portion 40a is formed at an electron gun. A long central slot 40c is formed parallel to the path of the emitted electron beam, and side slots 40d shorter than the length of the center slot 40c are formed at left and right sides of the center slot 40c. It is formed in parallel.

The side slots 40d are preferably formed to be symmetrical with respect to the tube axis direction central axis of the cathode ray tube, and are formed to be biased toward the panel side of the shield member 40.

3 is a front view showing a shield member according to an embodiment of the present invention.

As shown in FIG. 3, the lateral slot 40d according to the embodiment is formed as an elongated rectangular opening, and the width of the shield member 40 in the tube axis direction (Z direction) of the cathode ray tube is H, When the distance from the panel side of the shield member in the tube axis direction (Z direction) to the neck end of the lateral slot 40d is h, the shield member 40 is preferably formed by satisfying the following equation. Do.

15 ≤ (h / H) × 100 ≤60

In addition, the side slots 40d are formed parallel to the path of the electron beam emitted from the electron gun, and the long side length of the panel side of the shield member 40 is between W and the panel end portions of the side slots 40d which are symmetrical to each other. When the distance of w is, the shield member 40 is preferably formed by satisfying the following equation.

40 ≤ (w / W) × ≤60

Furthermore, when the long side length of the panel side of the shield member 40 is W and the short side length of the side slot 40d is L, the shield member 40 is preferably formed to satisfy the following equation.

1 ≤ (L / W) × 100 ≤7

4 is a plan view showing a shield member according to a second embodiment of the present invention, FIG. 5 is a plan view showing a shield member according to a third embodiment of the present invention, and FIG. 6 is a fourth view of the present invention. A plan view of a shield member according to an embodiment.

As shown in FIG. 4, the side slot 50d formed in the long side portion 50a of the shield member 50 according to the second embodiment of the present invention is formed as a triangular opening, and the triangle is a hypotenuse electron beam. Sides parallel to the path and facing each other based on the center slot 50c are parallel to the center slot 50c, and the other side is preferably formed to be parallel to the panel side of the shield member 50. .

As shown in Fig. 5, the side slot 54d formed in the long side portion 54a of the shield member 54 according to the third embodiment of the present invention is formed as an oval opening, and the long axis is It is generally arranged parallel to the path of the electron beam.

As shown in Fig. 6, the lateral slots 58d formed in the long side portion 58a of the shield member 58 according to the fourth embodiment of the present invention are formed as an opening of a parallelogram, and the parallelogram The long axis is arranged approximately parallel with the path of the electron beam.

7 is a cross-sectional view for explaining a process of changing the magnetic field by the side slot of the shield member according to the present invention.

As mentioned above, the electron beam 31 emitted from the electron gun 30 is changed by the Lorentz force while traveling inside the cathode ray tube toward the fluorescent screen, and in particular, the screen portion 20a of the Lorentz force. In the width direction (X direction) Under the force of, the movement path in the X direction is changed, that is, mislanded.

In general, when a shield member having no slot is formed in the long side portion, a magnetic field formed around a path through which an electron beam passes, has a positive B _y value on the neck side and passes through the middle of the shield member toward the panel. _{Has the} value of B _y .

However, when the shield member 40 having the side slot 40d according to the present invention is adopted, the side slot 40d opened upward in the process of passing through the middle portion of the shield member 40 toward the panel. 7, the absolute value of the negative B _y 33 according to the present invention becomes smaller than that of the conventional negative B _y 35 as shown in FIG. 7, which is the Lorentz force F _{x in} the X direction. Results in a decrease in size.

8 is a graph showing the distribution of the spatial magnetic field along the path of the electron beam in the cathode ray tube according to the present invention.

That is, it shows the magnetic flux density (B) with respect to the horizontal component of the geomagnetism according to the tube axis distance from the electron gun to the screen portion inside the cathode ray tube. For convenience, the left side on the X axis is in the necked direction of the cathode ray tube, The right side was viewed toward the fluorescent screen of the cathode ray tube and the distance on the axis of the tube on the X axis was shown as the starting point from the neck side. When showing the position of the shield member 40 according to the present invention on such a graph, it is located between approximately 90 mm to 230 mm, of which the area of the lateral slot 40d is between approximately 160 mm and 190 mm. It is located at.

As can be seen from the graph, on the shield member 40 of the present invention, the absolute value of the negative B _y distributed in the position where the side slot 40d is located is conventional (the side slot according to the present invention is a shield member). Since it is smaller than the absolute value of the negative B _y of the case), as a result, the X component of the Lorentz force, that is, the size of F _x can be reduced, thereby reducing the mislanding phenomenon of the electron beam.

Example 1

Electron beam when a conventional shield member is employed for a 22 "cathode ray tube of a tension mask type under the conditions of horizontal geomagnetic (B _h ) 300 mG and vertical geomagnetic (B _v ) 380 mG and when the shield member according to the present invention is employed. The amount of movement was measured.

In other words, as the distance from the vertical center of the screen to the edge is relatively shown, the vertical center point of the screen (15 mm away from the vertical end of the effective screen in the direction of the screen center) is 0, and the diagonal point of the screen ( 100 mm horizontally and vertically from the vertex) to 100%, and Table 1 shows the vertical beams of the screen and the NS beam horizontal component at 63%, 84% and 100% (diagonal) points. The amount of movement of the electron beam by the amount of movement and the horizontal component in the EW direction is measured and shown.

Prior art The present invention Position on screen 0 63% 84% 100% 0 63% 84% 100% Movement amount by N-S horizontal component [㎛] 27 27 22 12 26 26 21 9 Movement amount by E-W horizontal component [㎛] 6 8 16 17 5 6 17 16

As shown in Table 1, the amount of movement of the electron beam by the horizontal component in the EW direction is generally lower than that of the conventional one except for 84%, and the amount of movement of the electron beam by the horizontal component in the NS direction is lower than in the previous region. Especially, the movement amount was greatly decreased at the diagonal point of the screen (100%).

Example 2

In FIG. 9, the (w / W) × 100 is fixed to 50, and the (h / H) × 100 is changed from 10 to 90, and the amount of movement of the electron beam due to the NS-based horizontal component of the geomagnetic field is measured at a diagonal point. Indicated.

The movement amount of the electron beam is a relatively represents the movement amount of the electron beam measured by employing the shield member according to the present invention when the conventional movement amount is 100% at the same point. That is, when the value is less than 100%, the mislanding phenomenon of the electron beam is improved.

It can be seen from FIG. 9 that the amount of mislanding at the diagonal point greatly decreases when the value of (h / H) × 100 falls in the range of 20 to 60. FIG.

Example 3

Fig. 10 shows that at the diagonal point and the half diagonal point (the middle point of the reference point and the diagonal point of the screen) while fixing (h / H) × 100 to 50 and changing (w / W) × 100 from 10 to 90. The displacement of the electron beam due to the horizontal component of NS in the geomagnetic field is measured and shown.

The movement amount of the electron beam is a relatively represents the movement amount of the electron beam measured by employing the shield member according to the present invention when the conventional movement amount is 100% at the same point.

When the value of (w / W) x 100 is 40 or more and 60 or less from FIG. 10, the movement amount reduction effect in the diagonal and 1/2 diagonal point was obtained.

Example 4

11 is a horizontal component in the NS direction of the geomagnetism at a diagonal point while fixing (w / W) × 100 to 53 and changing (L / W) × 100 from 1 to 8 by changing the short side length L of the side slot. The movement amount of the electron beam is measured and shown.

11 shows the minimum amount of movement when the value of (L / W) × 100 is about 4, and it is possible to obtain the effect of reducing the amount of movement when the value is about 7 or less in consideration of the amount of movement by the horizontal component in the EW direction. Able to know.

In the above description, the tension mask type cathode ray tube has been described, but the shield member according to the present invention may be applied to a cathode ray tube of a formed mask type.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

As described above, according to the cathode ray tube provided with the shield member according to the present invention, a side slot parallel to the path of the electron beam is formed on the long side of the shield member so as to face the panel, so that the misbeaming of the electron beam by the NS component horizontal force of the geomagnetic field occurs. By reducing the amount has the effect of improving the color purity characteristics.

Claims (9)

A panel having a screen portion on which a fluorescent screen is formed and a side surface formed around the screen portion; A funnel connected to the panel and provided with a deflection device on an outer circumference thereof; A neck connected to the funnel and equipped with an electron gun for generating an electron beam scanned into the fluorescent screen therein; A color sorting apparatus mounted inside the panel to color-select the electron beam to reach a corresponding phosphor of the fluorescent screen; And Shield member for shielding the geomagnetism which is connected to the color sorting device and disposed toward the neck to affect the scanning trajectory of the electron beam Including, The shield member has a center slot which is formed in the center of the long side portion and is formed to be parallel to the path of the electron beam, and a side slot which is shorter than the length of the center slot on the left and right sides of the center slot is biased toward the panel and is formed in parallel with the path of the electron beam. tube. The method of claim 1, The side slots are formed in the cathode ray tube symmetrical with respect to the center axis of the tube axis (Z direction) of the cathode ray tube. The method of claim 2, The shield member is formed by satisfying the following equation when the length of the panel side of the shield member is W and the distance between the panel end portions of the side slots symmetric to each other is w. 40 ≤ (w / W) × 100 ≤60 The method of claim 1, When the width of the shield member in the tube axis direction (Z direction) of the cathode ray tube is H, and the distance from the panel side of the shield member in the tube axis direction (Z direction) to the neck end of the side slot is h. , The shield member is formed by satisfying the following equation. 15 ≤ (h / H) × 100 ≤60 The method of claim 1, When the long side length of the panel side of the shield member is W, the short side length of the lateral slot is L, the shield member is formed by satisfying the following equation. 1 ≤ (L / W) × 100 ≤7 The method of claim 1, wherein the color screening device A mask having a plurality of electron beam passing holes and having a shape in which a major axis and a minor axis are set; And A pair of support members disposed corresponding to the long axis of the mask at predetermined intervals and coupled to the mask stretched in one of the long and short axes, and the support being disposed corresponding to the short axis of the mask; A frame comprising a pair of rigid members fixed across both ends of the members to maintain tension applied to the mask; Cathode ray tube comprising a. The cathode ray tube of claim 1, wherein the lateral slot is formed of an elongated rectangular opening. The cathode ray tube of claim 1, wherein the lateral slot is formed by a triangular opening. The cathode ray tube of claim 1, wherein the lateral slot is formed of an opening having a parallelogram.