KR0183998B1 - Shadow mask for color cathode ray tube - Google Patents

Abstract

In order to prevent the occurrence of the moire pattern caused by matching the vertical pitch of the scanning line and the interval of the shadow mask aperture Pv in the color cathode ray tube 1, the shadow mask aperture Pv prevents the degradation of the resolution due to the movement of the shadow mask aperture Pv. A shadow mask of a color cathode ray tube in which a shadow mask aperture is arranged so that a ratio of the vertical pitch and the horizontal pitch of the mask aperture is 1: 0.69 to 0.83 to prevent a moire pattern.

Description

Shadow Mask for Color Cathode Ray Tubes

1 is a schematic cross-sectional view of an applied color cathode ray tube of the present invention.

2 is a partially enlarged view of a shadow mask according to the present invention.

3 is a partially enlarged view of a conventional shadow mask.

* Explanation of symbols for main parts of the drawings

1: color cathode ray tube 2: phosphor

3: panel 4: vertical edge

5: shadow mask 6: funnel

7 neck portion 8 electron gun

9: deflection yoke 10: electron beam

11: aperture

The present invention relates to a shadow mask for color cathode ray tube, and more particularly, to a shadow mask for color cathode ray tube that can prevent a moire pattern caused by interference between the vertical pitch of the shadow mask and the vertical pitch of the scanning line.

Generally, a color cathode ray tube reproduces an image by the electron beam radiating | emitted from an electron gun impinging on the fluorescent surface to which fluorescent substance is apply | coated through the shadow mask in which the several aperture is formed.

The shape and position of the electron beam is determined by the shadow mask, and about 85% of the electron beam is blocked by the shadow mask, and only about 15% of the electron beam reaches the fluorescent surface.

The electron beam that reaches the fluorescent surface reproduces the image by the carrier color signal, but not only the resolution of the image is reduced by the regular two sets of interference beads in the reproduced image, but also the vertical pitch and shadow mask of the electron beam passing through the shadow mask. Since the vertical pitch between the apertures formed at the same is the same, a moire pattern in which streaks are generated in the image due to both interferences is generated.

3 is a partially enlarged perspective view of a conventional shadow mask A, in which a plurality of spherical apertures B are formed in the shadow mask A in a constant arrangement.

The spherical aperture B is formed in the form of an equilateral triangle, and the distance between the vertical pitch Pv and the horizontal pitch Ph is determined by the following Equation (1).

Ph = Pv… … … … … … … … (One)

The shape of the aperture formed in the shadow mask A is generally divided into two types, a stripe type and a dot type.

Here, the stripe type has a slit shape of the aperture formed in the shadow mask, and thus, unlike the Pv of the shadow mask, the vertical pitch of the scan line is adjusted to prevent the moire pattern.

However, when the shape of the aperture is a dot-shaped shadow mask to prevent the moire pattern by changing the vertical pitch of the scanning line, the resolution of the image reproduced because the Ph of the spherical aperture arranged in an equilateral triangle and the horizontal pitch of the scanning line do not match. The problem of falling was generated.

Accordingly, an object of the present invention is to prevent the occurrence of the moire pattern caused by the coincidence of the vertical pitch of the scan line and the interval of the shadow mask aperture Pv, and to prevent the degradation of the resolution due to the movement of the shadow mask aperture Pv. The present invention provides a dot shadow mask.

In order to achieve the above object, the present invention is characterized in that the shadow mask aperture is arranged so that the ratio of the vertical pitch and the horizontal pitch of the shadow mask aperture is 1: 0.69 to 0.83.

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

1 is a schematic cross-sectional view of a color cathode ray tube 1 to which the present invention is applied, in which a shadow mask 5 is attached to a vertical edge 4 of a panel 3 to which a phosphor 2 is applied, and a funnel ( 6) are bonded to each other, and an electron gun 8 and a deflection yoke 9 are provided on the neck portion 7 of the funnel 6.

The electron beam 10 emitted from the electron gun 8 provided in the neck portion 7 of the funnel 6 is deflected by the flat yoke 9 and radiated to the outer portion of the shadow mask 5.

2 is a partially enlarged view of the shadow mask 5 according to the present invention, in which a plurality of apertures 11 formed in a predetermined pattern are formed in the shadow mask 5.

The predetermined pattern described above is determined by the following equation (2).

Ph = Ph x (0.8 to 0.96)... … … … … (2)

The vertical pitch of the scan line is predetermined so that a moire pattern does not occur when the electron beam collides with the shadow mask formed as described above.

As described above, the present invention can prevent the moire pattern and improve the resolution of the reproduced image by adjusting the vertical pitch and the horizontal pitch of the shadow mask differently.

Claims (1)

In the shadow mask A of the color cathode ray tube in which the spherical aperture B is formed in an equilateral triangle pattern, the horizontal pitch Ph of the shadow mask aperture 11 is 69 to 83 of the vertical pitch Pv. Shadow mask of color cathode ray tube, characterized in that the%.