KR100329592B1 - Material of spring to Bi-metal for color braun tube - Google Patents

Abstract

The present invention relates to the material and the size of the spring that serves to support the shadow mask used in the color-brown tube and the compensation role according to the thermal expansion of the shadow mask made of conventional Invar or aluminum-kilted steel (AK) only Instead, by arranging the STS 304H and STS 430H to be in contact with each other by the known continuous electron beam welding method, the 29 'SF type color brown tube for low expansion coefficient, excellent landing error compensation and low cost Bimetal spring material.

Description

Bimetal Spring Material for Color Braun Tubes {Material of spring to Bi-metal for color braun tube}

The present invention relates to a bimetal spring material for color brown tube, and more specifically, to a support panel on a panel, and more specifically, a 29 'SF type color brown that serves to compensate for thermal expansion of a shadow mask due to collision of an electron beam during operation of the CRT. It relates to a conventional bimetal spring material.

First, explaining the structure of the color-brown tube and the role of the spring in the color-brown tube, Figure 1 is a cross-sectional view showing a general color-brown tube, Figure 2 a, b, c shows a state diagram of the use of the spring.

The CRT consists of a rectangular panel 1 and a funnel 3 in which the neck portion 3a into which the electron gun 2 is sealed is integrally formed.

The panel 1 has a tube axis passing through the center thereof, and phosphors of three colors emitting blue, green, and red light are coated on the inner surface of the panel 1 to form a fluorescent surface 4, and in the vicinity of the fluorescent surface, there are a myriad of holes 5a. The shadow mask 5 is formed to serve as color screening of the electron beam. The shadow mask is welded and supported by the rectangular support frame 6.

The support frame 6 is fitted to the stud pin 8 fixed to the inner surface of the panel 1 by a plurality of springs 12 to maintain the suspended state to the panel (1).

The spring 12 is formed between the hole 5a formed in the shadow mask and the fluorescent surface 4 of the screen when the shadow mask 5 and the support frame 6 are heated and expanded due to the collision of the electron beam according to the operation of the CRT. To prevent discoloration (color distortion) caused by relative displacement,

Even when an impact is applied during the operation of the CRT, the applied impact is prevented from being transmitted to the shadow mask 5 side, thereby preventing the deterioration of color purity.

Springs and shadow masks in a CRT having such a structure are generally Invar, in which the support frame 6 is iron (Fe), and the shadow mask (5) is made of aluminum-kilted steel (AK) or Fe-Ni alloy. In order to reduce the compensation amount of the landing error of the electron beam 11 due to thermal expansion of the shadow mask 5, the material of the spring 12 is also Fe-Ni alloy such as shadow mask, Invar or aluminum. Kilda steel (AK) is used.

However, this Invar alloy is an alloy whose Ni content is 36% (the remainder is Fe), and its thermal expansion coefficient is very small at 1.2X10 ^-6 / ℃ or less at room temperature, so it is sensitive to thermal effects. As it is an alloy that contains a lot of expensive Ni, which is frequently used for the head support, the lead alloy of the lead frame, etc., the manufacturing cost of the spring material is increased, causing the cost of manufacturing the color-brown tube to be a problem. When used as a material, although the price is cheaper than the Inba alloy, there is a problem that the coefficient of thermal expansion is high.

The present invention has been made to solve such a problem in the prior art, using a bimetal material having a low thermal expansion coefficient and a relatively low thermal expansion coefficient instead of expensive invar alloy or aluminum-kilted steel with high thermal expansion coefficient, and according to the shape of the shadow mask. The purpose of the present invention is to improve the mislanding phenomenon of the electron beam due to thermal expansion of the shadow mask during the operation of the CRT.

According to the aspect of the present invention for achieving the above object, a plate of stainless steel STS 304H, stainless steel STS 430H is arranged side by side and the contact cross-section is a known continuous electron beam welding method (Applicant January 24, 1995 It is a technical problem to form a single spring plate by welding by the welding method shown in the trimetal manufacturing method for color-brown tubes filed in Patent 95-1120.

For reference, such a spring material forms a spring in the form as shown in FIG. 4, and this spring serves to fix the shadow mask to the panel as shown in FIGS. 2a, b, and c and serves as a compensator according to thermal expansion of the shadow mask. The mechanism that Spring acts as a calibrator is as follows.

1) Mask DOMING step

Only about 20% of the electron beam emitted from the electron gun collides with the phosphor-coated screen of the screen, and the rest of the electron beam collides with the shadow mask or the supporting frame to lose kinetic energy.

At this time, the frictional heat generated by the collision of the electron beam thermally expands the shadow mask, thereby causing a dominant phenomenon in which the mask curved portion swells in the screen direction, and the electron beam passing through the mask is moved toward the screen center by the displacement of the mask.

2) FRAME thermal expansion stage

The shadow mask, which has a relatively large number of electron beam collisions, has a low thermal capacity, thermally expands first, and then a dominant phenomenon occurs. Then, the shadow mask, which causes the dominant phenomenon, expands to the periphery of the screen as the support frame thermally expands in the peripheral direction of the screen.

The expansion of the mask causes the landing of the electron beam moving in the center direction of the screen to move in the peripheral direction again.

3) the displacement and stabilization stage of the spring

As the frame expands and the shadow mask expands in the circumferential direction, the spring welded to the frame also heats up, causing the bimetal action to lift the MASK ASS'Y toward the screen, while the landing of the electron beam gradually moves in the circumferential direction. Over time, it is a stable phase that balances incident energy and emitted energy and no further thermal displacement or landing changes occur.

4) Correction effect of spring

5) Spring compensation amount setting

The thermal displacement correction amount setting of the spring can be expressed as the following equation.

C: curvature constant L: length of specimen T: temperature displacement where D is ΔT is the value of thermal deformation (300 microns) of high expansion (STS304) and low expansion (STS430) due to temperature difference The value of D varies depending on the difference in the coefficient of thermal expansion. In addition, the coefficient of thermal expansion may vary depending on the chemical composition of the material.

1 is a cross-sectional view showing a typical color-brown tube

2, a, b, c is a partial longitudinal cross-sectional view illustrating the use state of the spring in the CRT

3A and 3B are perspective views of BI-Metal in which STS 430H and STS 304H alloy are integrally formed.

Figure 4 is a type of spring molded from bimetal or trimetal material

<Explanation of symbols for main parts of drawing>

1 panel 3 funnel

5: shadow mask 6: support frame

12: spring

Hereinafter, the present invention will be described in detail with reference to FIG. 3.

3A and 3B show bimetals made of a single metal strip using a continuous electron beam welding method for heterogeneous materials having different chemical compositions and mechanical properties, as shown in Tables 2 and 3, using STS 304H and STS 430H. It can be seen that the bimetal standard is determined as shown in Table 1 according to the type of CRT product.

TABLE 1

Bimetallic Standard Material Units m / m

Note 1: The thickness of the material is 1.2m / m.

Note 2: Tolerance of material thickness is ± 0.035m / m.

Note 3: Tolerance of width is ± 0.15m / m.

TABLE 2

TABLE 3

Bimetal spring material of 29 'SF type has very good bending constant and welding point tensile strength as shown in the physical properties shown in Table 4, and there is no significant difference in quality from springs using only Invar or aluminum-kilted steel (AK). Spring molding has the advantage of minimizing the loss of STS 430H, a low-expansion material in the center.

In addition, the reason for limiting the width and thickness of the STS 304H and STS 430H plates is that the bimetallic standard is consistently defined according to the color-brown tube specification. Measured by laser displacement (D) Calculated value of measured D Applied in (approximately 5.2 X 10 ^-6 / ℃), the material to be used should be different according to the degree of heat deformation in the CRT and the width and thickness of the material. According to the data of the C value, called the curvature constant, the thickness and width of the material must be varied so that the value of heat compensation depends on the degree of thermal deformation of the shadow mask frame inside the CRT. STS304 (high expansion) and STS430 (low expansion) are applied. For reference, two functions of the spring can be summarized. ① Mechanical function This function can support the shadow mask frame according to the size of the brown tube. Therefore, the mechanical strength should have tensile strength and elastic modulus to support the frame, and the thickness of the material should be selected. ② Thermal function The brown tube is an electron gun, which is to obtain the electron beam by colliding with the fluorescent film of the CRT Get the color of RG B. At this time, about 70% of the electron beam collides with the shadow mask to cause thermal deformation. The thermal compensation function (bimetal) for the thermal deformation is performed to obtain a clean color by matching the shadow mask of the CRT and the fluorescent film.

TABLE 4

As described above, the present invention replaces the spring material for the color brown tube with the so-called BI-Metal, which is integrally welded with STS 430H and STS 304H dissimilar metals instead of aluminum-kilted steel or expensive invar alloy. Even if the spring production cost is saved without reducing the performance of the spring, there is a cost reduction effect of the color brown tube.

Claims (2)

STS 430H stainless steel with C 0.12 wt% or less, Si 0.75 wt% or less, Mn 1.0 wt% or less, P 0.04 wt% or less, S 0.03 wt% or less, Ni 0.6 wt% or less, Cr 16-18.0 wt%, and the balance is Fe 0.12% or less of C, 1.0% or less of Si, 2.0% or less of Mn, P 0.03% or less, S 0.03% or less, Ni 8.0-10.5%, Cr 17.0-19.0%, and the balance of the steel plate Bimetal spring material for color brown tube, in which STS 304H stainless steel plate, which is Fe, is arranged and integrated with each other, by contact with each other, using a known continuous electron beam welding method. Claim 2 has been deleted.