KR100467427B1 - Shadow mask and manufacturing method - Google Patents

Abstract

A second layer formed of AK steel having a Ni content of 0.001 to 0.02 wt% and an Inba steel having a Cr content of 0.02 to 0.10 wt% and an Al content of 0.005 to 0.01 wt%, and a second layer formed on the first layer. Etching the composite sheet comprising a, and forming the etched mask at room temperature to provide a method for producing a shadow mask.

Description

Shadow Masks and Methods for Making the Same

[Industrial use]

The present invention relates to a shadow mask and a method for manufacturing the same, and more particularly, to a shadow mask having excellent mechanical strength and a method for manufacturing a shadow mask capable of simply and economically manufacturing such a shadow mask.

[Prior art]

Shadow masks used in color TVs, color monitors, and the like have a color screening function for selecting an electron beam irradiated from an electron gun. About 20% of the electron beam irradiated from the electron gun passes through the hole formed in the shadow mask, and about 80% of the electron beam collides with the shadow mask, thereby raising the temperature of the shadow mask, thereby causing the shadowing of the shadow mask. . Due to such a domming phenomenon, the color purity decreases as the position of the shadow mask hole through which the electron beam passes is changed from the reference position.

In order to prevent such a shadow mask from thermal expansion, a shadow mask is manufactured using a material having a low coefficient of thermal expansion. As such a material having a low coefficient of thermal expansion, an Invar alloy having a very low coefficient of thermal expansion of 0.0000008 / ° C is mainly used. The Invar alloy has a very low coefficient of thermal expansion and hardly expands regardless of temperature rise due to radiation collision of the electron beam.

However, even when the above-described Invar alloy is used, since the Invar alloy has a small modulus of elasticity, the shadow mask vibrates due to sound signals such as sound waves, and color purity is lowered. In order to solve this problem, a method of manufacturing a shadow mask having a low coefficient of thermal expansion and a high modulus of elasticity using a composite material in which steel layers are integrally formed on both sides of an Invar alloy is described in Japanese Laid-Open Patent Publication No. 5-47311. have. However, the above method has a problem in that the manufacturing process is difficult because it consists of a three-layer structure of Inba steel, steel and Inba steel.

In order to prevent the doming phenomenon in which the thermal expansion of the shadow mask occurs due to the heat generated by the collision of the electron beam, a method of manufacturing the shadow mask from two or more metal layers having different thermal expansion rates is described in Korean Patent Application No. 89-20775. have. However, the above method did not show as much as expected the effect of suppressing the dominant phenomenon of the shadow mask, there is a disadvantage that processing and molding is difficult.

In addition, US Patent Publication No. 5,079,477 discloses a technique for manufacturing a double-sided shadow mask having a different arrangement of slots in order to prevent the electron beam transmissivity from changing due to thermal expansion of the shadow mask. Described. This method uses AK steel or Invar steel and makes the slot arrangement a predetermined pitch by overlapping each other by increasing the pitch of AK and Invar steel more than twice the design pitch. This method, however, forms slots having different pitch sizes in sheets of different materials, and then joins them, which complicates the manufacturing process, and the gist thereof also does not produce a composite sheet, but merely an arrangement of slots in each layer. Is a technique for increasing the electron beam transmittance by forming differently.

In addition, in order to perform press molding in the process of manufacturing a shadow mask using Invar alloy, the annealing heat treatment should be performed several times to lower the tensile strength and the yield strength so as to improve the press formability. However, performing the annealing heat treatment several times as described above has a problem in that the manufacturing cost due to the increase in the number of processes and the heat treatment increases. In order to solve this problem, Korean Patent Publication No. 93-7092 adds a small amount of alloying elements such as P and S to an Invar steel having a low coefficient of thermal expansion, thereby annealing to impart press formability while improving the mechanical properties of the shadow mask. The method of performing heat treatment only once is described. However, this method also needs to be subjected to annealing heat treatment, which does not completely eliminate the problems of the increase in the number of processes and the manufacturing cost due to the heat treatment.

In addition, all the above-described method for manufacturing the shadow mask must lower the yield strength of the alloy material in order to perform the press molding process. Therefore, in order to reduce yield strength, the warm shaping | molding method which performs a press molding process at the temperature higher than normal temperature is used. However, in order to perform such warm molding, a separate apparatus for increasing the temperature is required, which causes a problem in that the manufacturing cost is high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a shadow mask having a low coefficient of thermal expansion, which can prevent a dominant phenomenon due to thermal expansion.

Another object of the present invention is to provide a method for producing a shadow mask that can be molded at room temperature using an alloy material having a low yield strength.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a first layer formed of AK steel having a Ni content of 0.001 to 0.02% by weight; and an Inba steel having a Cr content of 0.02 to 0.10% by weight and an Al content of 0.005 to 0.01% by weight. And a second layer formed on the first layer.

In addition, the first layer formed of AK steel having a Ni content of 0.001 to 0.02% by weight and the Inba steel having a Cr content of 0.02 to 0.10% by weight and an Al content of 0.005 to 0.01% by weight, the first layer formed on the first layer Etching a flat mask of a double structure consisting of two layers; It provides a method for producing a shadow mask comprising the step of molding the etched mask at room temperature.

Hereinafter, the present invention will be described in more detail.

A second layer formed of AK steel having a Ni content of 0.001 to 0.02 wt% and an Inba steel having a Cr content of 0.02 to 0.10 wt% and an Al content of 0.005 to 0.01 wt%, and a second layer formed on the first layer. To form a flat mask plate of the composite sheet consisting of. The composite sheet is formed by joining the first layer and the second layer in a cladding manner. Cladding method refers to a method of bonding a thin plate of different material to the surface of the substrate.

If the content of Ni contained in the composite sheet in the AK steel is 0.001 to 0.02% by weight, toughness is preferably increased. Young's modulus is improved when the content of Cr contained in the Invar steel in the composite sheet is 0.02 to 0.10 wt%. In addition, when the content of Al contained in the Invar steel in the composite sheet is 0.005 to 0.01 wt%, it is preferable because it can prevent the strainer strain (strecher strain) that the surface wrinkles occur.

The photosensitive liquid is apply | coated to the flat mask board formed from the said composite sheet. The mask plate is exposed, developed and then etched to form holes through which the electron beam can pass. As described above, an annealing process is performed in which the shadow mask having the hole is heat-treated in a hydrogen atmosphere of about 800 ° C. to remove the internal stress of the mask and impart ductility.

Subsequently, the mask is molded at room temperature in a constant form by pressing. The degreasing process is performed on the mask plate formed at room temperature to remove foreign substances such as contamination and fingerprints. Next, a blackening process is performed to manufacture the shadow mask.

In general, if the yield strength of the alloying material for producing the shadow mask is too high, too high pressure must be applied in the press forming process during the manufacturing process of the shadow mask. Therefore, the method of lowering the yield strength of the alloying material used in order to perform a press molding process at low pressure is used. Thus, in order to lower the yield strength of an alloy, the press molding process is performed by the warm forming process which performs at temperature higher than normal temperature. However, such a warm molding process can be easily carried out by press molding, but a separate device for increasing the temperature is required and the total manufacturing process number is increased, thereby increasing the manufacturing cost.

The composite sheet for shadow mask of the present invention is composed of AK steel further added Ni and Cr-Inba steel further added Cr and Al content is changed. As such, changing the amount of the component lowers mechanical properties, in particular yield point. Therefore, it is not necessary to perform warm molding in order to perform press molding, and it is possible to mold at normal temperature.

EXAMPLE

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention and the present invention is not limited to the following examples.

(Example 1)

A flat mask plate of a composite sheet by joining a first layer formed of AK steel having a Ni content of 0.02% by weight and a second layer formed of an Invar steel having a content of Cr of 0.03% by weight and a content of 0.005% by weight of Al by cladding. Formed.

The photosensitive liquid was apply | coated to the flat mask board formed from the said composite sheet. The mask plate was exposed, developed and then etched to form holes through which the electron beam could pass. Thus, the annealing process of heat-processing the shadow mask in which the hole was formed in the hydrogen atmosphere of about 800 degreeC was implemented, the internal stress of the mask was removed, and ductility was provided.

Subsequently, the mask was molded at room temperature in a constant form by a press. The moldable mask plate was subjected to a degreasing process to remove foreign substances such as contamination and fingerprints. Subsequently, the blackening process was performed to manufacture the shadow mask.

The chemical composition of each of the composite sheet used in Example 1 and the conventional AK steel and Inva steel is shown in Table 1 below (unit of each component shown in Table 1 is% by weight).

C Si Mn P S Cr Cu Al Ni Fe Example 1 AK River 0.05 0.01 0.28 0.013 0.003 0.05 0.01 0.06 0.02 Balance Inba River 0.005 0.06 0.22 0.003 0.03 0.03 0.005 36 balance AK River 0.004 0.04 0.2 to 0.4 0.018 0.015 0.05 0.08 0.03 to 0.08 balance Inba River 0.04 0.25 0.25 to 0.4 0.012 0.012 35.5 balance

The tensile strength, yield point, elongation, thermal expansion coefficient and Young's modulus of the composite sheet of Example 1 and AK steel and Invar steel were measured, and the results are shown in Table 2 below.

Tensile Strength [㎏ / ㎠] Yield Point [㎏ / ㎠] Elongation [%] (ε) Coefficient of thermal expansion (α) Young's modulus [㎏ / ㎠] Example 1 45 43 5.8 3 × 10 ⁶ 17,000 AK River 66 60 2 11 × 10 ⁶ 21,000 Inba River 60 60 13 1 × 10 ⁶ 9,700

As shown in Table 2, the composite sheet of the present invention can be prevented from expanding by the heat generated by the electron beam impact is low thermal expansion coefficient. Moreover, yield point is low enough to perform press molding, and favorable press molding can be performed even at normal temperature, without the need of warm forming with such a composite sheet. In addition, the elongation is high, so molding is easy. In addition, as shown in Table 2, the composite sheet of the present invention is lower than AK steel, but has a higher Young's modulus than Inba steel. The higher the Young's modulus, the smaller the deflection of the substrate, and therefore, the deflection of the composite sheet of the present invention is smaller than that of Invar Steel. That is, it can be seen that the structural strength is superior to the Invar strength.

The present invention can be carried out at room temperature press molding in the process of manufacturing the shadow mask. In addition, the thermal expansion characteristic has a value similar to that of the Invar steel and thus is not expanded by the heat generated by the electron beam collision. In addition, the structural strength including impact resistance is superior to Invar steel.

Claims (4)

A first layer formed of AK steel having a Ni content of 0.001 to 0.02% by weight; and A second layer formed of Invar steel having a Cr content of 0.02 to 0.10% by weight and an Al content of 0.005 to 0.01% by weight, and formed on the first layer; Shadow mask comprising. The shadow mask of claim 1, wherein the second layer is bonded to the first layer by a clad method. A second layer formed of AK steel having a Ni content of 0.001 to 0.02 wt% and an Inba steel having a Cr content of 0.02 to 0.10 wt% and an Al content of 0.005 to 0.01 wt%, and a second layer formed on the first layer. Etching the flat mask of the dual structure consisting of; Shaping the etched mask at room temperature; The manufacturing method of the shadow mask containing the process. The method of claim 3, wherein the second layer is bonded to the first layer by a clad method.