KR100414495B1 - Transposed scan CRT - Google Patents

Abstract

The present invention relates to an inner shield of a vertical scanning cathode ray tube.

According to the present invention, a panel having a flat outer surface, a funnel coupled to a rear surface of the panel, and three cathodes generating three color electron beams of R (Red), G (Green), and B (Blue) are arranged in a vertical line. And a deflection yoke composed of a vertical gun for forming a pincushion magnetic field for deflecting the electron beam in a short axis direction, and a horizontal coil for forming a barrel-shaped deflection magnetic field for deflecting the electron beam in a long axis direction, and an inner surface of the funnel. In the vertical scanning cathode ray tube including an inner shield for shielding the external geomagnetic field, the length of the bottom portion of the notch of the long side of the inner shield is a, the bottom of the notch of the short side of the inner shield When the sub-length is b and the length of the short side of the lower end of the inner shield is BL, the following equation is satisfied at the same time.

0.122 ≤ b / BL <0.61 and 0.01 ≤ a / b <1.00

Therefore, according to the present invention, it is possible to reduce the deflection variation generated in the vertical scanning cathode ray tube, thereby preventing the degradation of the color purity and the resolution of the image quality.

Description

Vertical scanning cathode ray tube {Transposed scan CRT}

The present invention relates to a vertical scan type cathode ray tube, and more particularly, to a vertical scan type inner shield which prevents an electron beam injected from an electron gun from being mislanded by the influence of a vertical residual magnetic field.

1 is a vertical sectional view of a vertical scanning cathode ray tube.

As shown in FIG. 1, the vertical scanning cathode ray tube includes a panel 1 having a flat outer surface and a phosphor 3 coated thereon, a funnel 11 coupled to a rear surface of the panel, R (Red), and G ( Green), three cathodes generating electron beams 8, 9, and 10 of B (Blue) colors are arranged in a vertical inline, and the electron beam emitted from the electron gun strikes a fluorescent surface to reproduce colors. A deflection yoke (5) comprising a screen (2), a vertical coil for forming a pincushion magnetic field for deflecting the electron beam in the short axis direction, and a horizontal coil for forming a barrel-shaped deflection magnetic field for deflecting the electron beam in the long axis direction, the electron beam The shadow mask 6 having the long axes of the long axis passing therethrough, the frame 30 supporting the shadow mask 6, and the frame 30 are combined to allow the cathode ray tube to be less affected by an external geomagnetic field during operation. Consists of inner shield (20) that serves as a shield There.

The cathode ray tube of FIG. 1 configured as described above is accelerated and focused while the electron beams of three colors R, G, and B, in which an electron beam is generated from the cathode, are sequentially passed through a plurality of electrodes, and then deflected. Scanned toward the screen 2 in a state deflected in the vertical and horizontal directions by the magnetic field of the yoke 5.

The electron beam scanned as described above passes through an elongated electron beam passing hole at the long axis of the shadow mask 6 which serves as color screening, and emits the phosphor 3 coated on the inner surface of the panel 1, thereby reproducing an image.

In the vertical scanning type cathode ray tube as shown in FIG. 1, the electron beam emitted from the electron gun 4 is affected by an external geomagnetic field in the process of forming an image.

When the cathode ray tube is driven, the influence of the external geomagnetic field acts in various directions depending on the installation position of the cathode ray tube. The geomagnetic field is horizontal (east-west direction) with respect to the trajectory of the electron beam emitted from the electron gun of the cathode ray tube. It acts in the vertical direction (the north-south direction).

2 is a view showing the shape of the inner shield of the horizontal scanning cathode ray tube according to the prior art.

The inner shield 20 of FIG. 2, which is coupled to the frame supporting the shadow mask and installed inside the cathode ray tube, changes the trajectory of the electron beam 6 by an external geomagnetic field and emits phosphors at different positions. Used to prevent the color purity of the screen from dropping.

As shown in FIG. 2, the inner shield 20 surrounds a free space in which the electron beam emitted from the electron gun is moved, thereby reducing the influence of the electron beam by the external geomagnetic field.

The plate member is bent to provide an opening 21 at an upper portion thereof, and a fixing portion 23 fixed to a main body 22 having a rectangular pyramid shape and a frame 30 supporting a shadow mask at a lower portion thereof. The long side notch (a) is formed in the long side surface part of the main body 22, and the short side notch (b) is formed in the short side surface part.

In the case of the conventional horizontal scanning cathode ray tube, as shown in FIG. 2, the short side notch (a) is formed longer than the bottom side length (b) of the short side notch (Notch). The magnetic field in the horizontal direction was enhanced by concentrating the geomagnetic field on the length (b) of the bottom of the notch.

However, in the vertical scanning type cathode ray tube of FIG. 1, the bottom portion length a of the long side notch notch is longer than the bottom length b of the short side notch as shown in FIG. 2. In the case of using the inner shield, the electron beam scanned from the electron gun is affected by the vertical residual magnetic field, which causes a deviation of the deflection, thereby degrading the color purity and reducing the resolution of the image quality.

Accordingly, it is an object of the present invention to solve the conventional problems, and to provide an inner shield to prevent the phenomenon that the electron beam scanned from the electron gun in the vertical scanning type cathode ray tube is not landed under the influence of the external geomagnetic field. .

1 is a vertical cross-sectional view of the vertical scanning cathode ray tube.

Figure 2 is a view showing the shape of the inner shield of the horizontal scanning cathode ray tube according to the prior art.

Figure 3 is a view showing the shape of the inner shield of the vertical scanning cathode ray tube according to the present invention.

*** Explanation of symbols for the main parts of the drawing ***

2: screen 3: phosphor

6: shadow mask 20: inner shield

30: Frame

The present invention for achieving the object as described above, a panel having a flat outer surface, a funnel coupled to the rear of the panel, three generating electron beams of three colors (R (Red), G (Green), B (Blue)) Yoke consisting of an electron gun having two cathodes arranged in a vertical inline, a vertical coil forming a pincushion magnetic field for deflecting the electron beam in the short axis direction, and a horizontal coil forming a barrel-shaped deflection magnetic field for deflecting the electron beam in the long axis direction, and In the vertical scanning type cathode ray tube including an inner shield formed along the inner surface of the funnel to shield the external geomagnetic field, the length of the bottom surface of the notch of the long side of the inner shield is a, the short side of the inner shield When the length of the bottom part of the notch is b and the short side length of the lower end of the inner shield is BL, it satisfies the following equation: 0.01 ≦ a / b <1.00, 0.122 ≦ b / BL <0.61 Characteristic It is done.

Hereinafter, with reference to the accompanying drawings, the present invention to achieve the above object will be described in detail.

As shown in FIG. 1, the panel 1 has a flat outer surface and is coated with a phosphor 3, a funnel 11 coupled to a rear surface of the panel, R (Red), G (Green), An electron gun 4 in which three cathodes generating B (Blue) three-color electron beams 8, 9, and 10 are arranged in a vertical inline, and a screen on which the electron beam emitted from the electron gun strikes a fluorescent surface to reproduce color. 2), a deflection yoke (5) consisting of a vertical coil for forming a pincushion magnetic field for deflecting the electron beam in a short axis direction, and a horizontal coil for forming a barrel-type deflection magnetic field for deflecting the electron beam in the long axis direction, and the electron beam passes through A shadow mask 6 having long axes of long axes formed therein, a frame 30 supporting the shadow mask 3, and a frame 30 are shielded so that the cathode ray tube is less affected by an external geomagnetic field during operation. Upper and lower injection composed of inner shield (20) A cathode ray tube.

The inner shield used to protect the trajectory of the electron beam scanned from the electron gun in the vertical scanning cathode ray tube from the influence of the external geomagnetic field has a notch (a) of the bottom of the notch of the long side. By forming the bottom portion (b) shorter than the length of the bottom portion, the geomagnetic field shielding effect in the vertical direction is increased to shield the vertical region from the influence of the geomagnetic field during scanning of the electron beam, thereby preventing the electron beam from being distorted.

In order to prevent the distortion of the electron beam trajectory as described above, in FIG. 3, the bottom portion a of the long side notch of the inner shield 20 and the bottom portion of the short side notch of the inner shield 20 are illustrated in FIG. 3. The length b and the short side length BL of the inner shield lower end 23 satisfy the following equation.

0.122 ≤ b / BL <0.61 and 0.01 ≤ a / b <1.00

Table 1 below shows the average test results in which the mis-landing of the corner occurs when the trajectory of the electron beam rotates westward in the 19-inch vertical injection CDT (Color Display Tube).

Table 1

Measured value: Corner miss landing (㎛) Length of bottom part of long side notch (a) (mm) 10 15 20 30 50 80 100 130 Short Side Notch (B) Dimensions (mm) 165 6 7 10 10 9 13 13 14 150 3 2 3 6 7 9 11 11 130 2 2 3 5 8 12 11 13 100 2 3 4 6 12 11 14 26 80 3 4 5 8 9 14 25 33 50 4 6 8 12 13 23 21 30 7 8 13 17 15 25 28 20 14 15 16 30 15 13 15 27 Unmeasurable area 10 15

As shown in the experimental results of Table 1, the relationship between the bottom length notch (a) of the long side notch of the inner shield and the bottom length b of the short side notch (b) of the inner shield of FIG. It shows a close relationship with the amount of mis-landing of corner at the time of direction rotation, and the relation between bottom length (a) of long side notch (a) and bottom length (b) of short side notch (b) is a / b <1.00. It can be seen that the mislanding is significantly less in the region.

However, even if the relation between the bottom length a of the long side notch Nota and the bottom length b of the short side Notch is a / b < 1, the bottom length of the short Notch Notch ( b) is limited by the short side length BL of the bottom 23 of the inner shield 20 coupled with the frame 30 supporting the shadow mask in FIG.

In Table 1, the short side length BL of the inner shield used for the 19 inch vertical scanning cathode ray tube was applied to 245 mm, and the short side length BL of the inner shield bottom used for the 19 inch cathode ray tube was also described above. Have similar dimensions.

In the region where the relation between the bottom length b of the short side notch of the inner shield and the short side length BL of the inner shield bottom is 0.122 ≦ b / BL <0.61, the bottom of the long side notch is generally used. As the relationship between the length a and the bottom length b of the short side notch Notb is a / b <1, the amount of mislanding decreases.

However, in the region where the relation between the bottom length b of the short side notch and the short side length BL of the inner shield bottom is 0.122> b / BL, the bottom length a of the long side notch Nota and Even if the relationship between the bottom length b of the short side notch is a / b < 1, the amount of mislanding is suddenly increased to lower the purity and the white uniformity characteristics.

In addition, the relation between the bottom length b of the short side notch and the short side length BL at the bottom of the inner shield is b / BL? 0.61, and the bottom length a of the long side notch Nota Even if the relationship between the bottom length b of the short side notch is a / b <1, the amount of mislanding is increased again.

Therefore, according to the present invention, the bottom magnetic field length (a) of the long side notch (Notch) of the inner shield of the upper and lower scanning type cathode ray tubes is formed shorter than the bottom length (b) of the short side notch (Notch). Due to this effect, the phenomenon of mislanding can be prevented and the resolution of color purity and image quality can be improved.

Claims (1)

Panel having a flat outer surface, funnel coupled to the rear of the panel, three cathodes generating three color electron beams of R (Red), G (Green) and B (Blue), in an axial direction A deflection yoke composed of a vertical coil forming a pincushion magnetic field for deflecting the electron beam and a horizontal coil forming a barrel-shaped deflection magnetic field for deflecting the electron beam in the long axis direction, and formed along an inner surface of the funnel to shield an external geomagnetic field. In the vertical scanning cathode ray tube containing an inner shield, When the length of the bottom of the notch of the long side of the inner shield is a, the length of the bottom of the notch of the short side of the inner shield is b, and the length of the short side of the bottom of the inner shield is BL. Up and down scanning cathode ray tube, characterized in that the following formula, satisfying 0.01 <a / b <1.00, 0.122 <b / BL <0.61 at the same time.