KR20040059962A - Shadowmask for color cathode-ray tube - Google Patents

Abstract

PURPOSE: A shadow mask is provided to achieve improved strength and reduce a thermal expansion by reducing the size of particle and thickness of shadow mask. CONSTITUTION: A shadow mask has a composition of 35.0 to 45.0 weight% Ni, 54.8 to 64.8 weight% Fe, 0.1 weight% C, and 0.1 weight% S. The shadow mask has a particle size of 7 to 100nm, and a thickness of 0.02 to 0.05mm. The shadow mask is manufactured through an electro-plating process. The shadow mask has an increased strength and low thermal expansion since the shadow mask has a small particle size and thickness. When the shadow mask is mounted in a cathode ray tube, a low initial tension is required.

Description

Shadow mask for color CRT tube {SHADOWMASK FOR COLOR CATHODE-RAY TUBE}

The present invention relates to a shadow mask for color CRT tubes with improved strength.

The color CRT consists of a panel coated with a fluorescent film on the inner side and a funnel coated with graphite on the inner side. The panel and the funnel are integrally coupled to each other by fusion glass. An electron gun for generating an electron beam is installed at the end of the funnel, and a deflection yoke for deflecting the electron beam is installed at the neck of the funnel. In addition, a shadow mask having a plurality of slots is provided inside the panel, and the electron beam generated by the electron gun collides with the fluorescent film through the slot.

The operation of the color CRT will be described.

When an image signal is input to the electron gun, hot electrons are emitted from the electron gun, and the emitted electrons are accelerated and focused by an acceleration electrode and a focusing electrode of the electron gun, and proceed to the panel side in the form of a beam. The electron beam passes through the slots of the shadow mask to perform color screening. The selected electron beam collides with the fluorescent film applied to the inner surface of the panel. Then, the fluorescent film is emitted to reproduce an image signal.

Since the accelerated electrons collide with the shadow mask in the color CRT as described above, when the color CRT is used for a long time, the shadow mask is thermally expanded and skewed. This causes deviation of the position of the electron beam with respect to the fluorescent film, and color shift occurs in the image. This phenomenon is called a doming effect. In order to minimize the doming effect, tension is applied to the shadow mask and installed.

The conventional shadow mask installed in the color CRT is formed by forming a plate having a thickness of 0.1 to 0.3 mm by cold rolling low carbon steel whose main component is Fe, and then forming a pattern by etching.

However, such a conventional shadow mask made of low carbon steel has a weak strength due to its thick thickness.

In addition, the conventional shadow mask has to be installed in the CRT so that high tensile force is applied because the thermal expansion rate is large due to the temperature rise. However, due to the weak strength of the shadow mask, it is difficult to apply a high tension force.

In addition, the conventional shadow mask has a disadvantage in that a sufficient magnetic sealing effect is not obtained due to its characteristics.

The present invention was created to solve the above problems of the prior art, an object of the present invention is to form a Fe-Ni alloy with a particle size of 7 nm to 100 nm and a thickness of 0.02 ~ 0.05 mm to improve the strength In addition, the present invention provides a shadow mask for a color CRT tube that can reduce thermal expansion rate.

Color shadow tube shadow mask according to the present invention for achieving the above object in the shadow mask for color CRT,

The shadow mask has a composition of Ni = 35.0 to 45.0% by weight, Fe = 54.8 to 6.68% by weight, C = 0.1% by weight and S = 0.1% by weight, the particle size is 7 nm to 100 nm, and the thickness is 0.02 to 0.05 mm.

Hereinafter, a shadow mask for a color CRT according to a preferred embodiment of the present invention will be described in detail.

The shadow mask for a color CRT tube according to this embodiment is composed of a composition of Ni = 35.0 to 45.0% by weight, Fe = 54.8 to 6.68% by weight, C = 0.1% by weight and S = 0.1% by weight. The amount of Ni is appropriate in the above range because the coefficient of thermal expansion increases when it is out of the above range. The shadow mask has a particle size of 7 nm to 100 nm and a thickness of 0.02 to 0.05 mm. That is, after the Ni-Fe alloy plate having a particle size of 7 nm to 100 nm and a thickness of 0.02 to 0.05 mm by electroplating, a slot is formed by photolithography and etching to prepare a shadow mask.

Since the shadow mask according to the present embodiment has a very small particle size and a very thin thickness, the shadow mask has a very high strength and a low thermal expansion rate. Therefore, when the shadow mask is installed in the CRT, it is possible to install by applying a small initial tension, which will be described with reference to Table 1.

The shadow mask prepared according to this embodiment is prepared in the composition of Ni = 38% by weight, Fe = 61.8% by weight, C = 0.1% by weight and S = 0.1% by weight, the particle size is 50nm, thickness 0.05mm to be.

Conventional shadow masks are prepared in compositions of Fe = 99.766% by weight, C = 0.002% by weight, Si = 0.01% by weight, Mn = 0.20% by weight, P = 0.015% by weight and S = 0.007% by weight, with a thickness of 0.1 mm. Is provided.

Values comparing the characteristic values of the shadow mask according to the present embodiment and the conventional shadow mask division Size of Crystal Particles (㎛) Thickness (mm) Transmittance (%) Tensile Strength (N / ㎡) Thermal expansion rate (x 10 ^-7 / ℃) Coercive force (Hc) Shadow mask according to this embodiment 0.01 0.05 19.0 1500 2.4 40 Conventional Shadow Mask 10 0.1 19.0 850 12.5 130

As shown in Table 1, the crystal grains and the thickness of the shadow mask according to the present embodiment correspond to 1/100 and 1/3 compared to the crystal grains and the thickness of the conventional shadow mask. As a result, the tensile strength of the shadow mask according to the present embodiment is about twice as large, and the coefficient of thermal expansion is reduced to 1/5. That is, since the shadow mask according to the present embodiment is a thin plate having a low expansion ratio, the shadow mask may be installed in the CRT by applying a small initial tension and have a high magnetic sealing effect.

The tensile strength shown in Table 1 was measured by JIS Z2241 using the 5th test piece based on JIS Z2210. The coercive force was measured by the VSM.

As described above, the shadow mask for color CRT tubes according to the present invention has a very small crystal grain size and a very thin thickness, thereby improving strength and decreasing thermal expansion rate. Therefore, it is very convenient because it can be installed in the CRT by applying a small initial tension.

Moreover, the magnetic sealing effect improves by the characteristic.

In the above, the present invention has been described in accordance with one embodiment of the present invention, but those skilled in the art to which the present invention pertains have been changed and modified without departing from the spirit of the present invention. Of course.

Claims (2)

In the shadow mask for color CRT, The shadow mask has a composition of Ni = 35.0 to 45.0% by weight, Fe = 54.8 to 6.68% by weight, C = 0.1% by weight and S = 0.1% by weight, the particle size is 7 nm to 100 nm, and the thickness is 0.02 to It is 0.05 mm, The shadow mask for color CRT tubes. The method of claim 1, The shadow mask is a shadow mask mask for color tube, characterized in that made by electroplating.