JPH029655B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a low thermal expansion alloy thin plate with excellent etching properties suitable for use as a shadow mask original plate for televisions, and a method for manufacturing the same.

[Technical Background of the Invention and Problems thereof] In recent years, as color television picture tubes have become more precise, attempts have been made to use low thermal expansion alloy thin plates with excellent etching properties for shadow masks. A picture tube using this shadow mask usually has a shadow mask 1 having a large number of electron beam passage holes, and a tricolor fluorescent lamp formed corresponding to each of the electron beam passage holes, as shown in perspective in FIG. 1. It has a light surface 2, and colors are selected by the respective incident angles of three electron beams from an electron gun 3 that enter an electron beam passage hole.

The shape of the electron beam passage hole is such as to avoid the generation of scattered electrons, as shown in cross section in FIG. 2, for example. However, with the conventional technology, when the resolution is increased, the accuracy is high as shown in Figure 2.
It is difficult to uniformly provide electron beam passage holes, and there is a drawback that a decrease in color purity, called a doming phenomenon, is likely to occur. In other words, recently there has been an increase in the general demand for "fine detail" on TV screens, and the transmission method is being changed to a method called high-definition television. There was a need for a shadow mask with high-density, high-precision beam passage holes and small pitch.

To this end, it has been desired to develop a low thermal expansion alloy thin plate that has low thermal expansion and excellent etching properties that allow fine and highly accurate etching.

[Purpose of the invention]

In view of the above points, the present invention provides a low thermal expansion alloy thin plate that has low thermal expansion and excellent etching properties, and is capable of forming fine patterns that can be etched with fine and high precision, and a method for manufacturing the same. The purpose is to do.

[Summary of the invention]

In the present invention, when forming a fine pattern on a thin alloy plate made of an Invar alloy by photoetching, the etching speed must be kept constant over the entire surface in order to make the size and shape fine and uniform over the entire surface. The present invention focuses on the fact that this can be achieved by defining the crystal plane of the etching surface as a specific crystal plane.

In other words, the thin alloy sheet according to the present invention is one in which 35% or more of {100} crystal planes are aggregated on the surface of the thin sheet made of an Invar alloy having a face-centered cubic lattice structure, that is, on the rolled surface that is the surface to be etched. Preferably, 40% or more of the {100} crystal faces are aggregated.

Here, the degree to which {100} crystal planes are clustered is
It is defined as follows. That is, the component of the <100> crystal axis direction of each polycrystalline grain in the direction perpendicular to the mask surface is defined as the following amount, which is the summed ratio for all crystallinities.

∫〓 ^/2 ₀ Vφcos ² dφ − Here, Vφ is the grain volume ratio, and φ is the angle between the direction perpendicular to the mask surface and the <100> crystal axis.

In other words, especially in Invar-type alloys, if the crystal grains are irregular on the etching plane and the direction of the {100} crystal plane is different, the etching rate will be significantly different between the crystal grains that are easily etched and the crystal grains that are difficult to etch. It becomes difficult to obtain fine electron beam passage holes with high density and high precision.

Further, the manufacturing method according to the present invention is a manufacturing method in which the etched plane is aligned with the {100} crystal plane as described above.
First, an Invar-type alloy having a face-centered cubic lattice structure is forged, and then in the hot rolling process, which is the main wall thickness reduction process, 35% or more of {100} crystal planes gather on the rolled surface. In other words, in the case of an Invar alloy having a face-centered cubic lattice structure, 35% or more of {100} crystal planes gather on the rolled surface during the hot rolling process, which is a wall thickness reduction process. Next, cold working at a rolling rate of 50% or less and strain relief heat treatment are repeated multiple times as necessary to form a thin plate. The reason why the cold working is performed at a rolling rate of 50% or less per time is to prevent the crystal direction of the rolled surface from shifting from the {100} plane when strong working is performed. Further, the rolling ratio during the above-mentioned cold rolling is preferably set to 10% to 30% in practical terms.

Note that the Invar type alloy with a face-centered cubic lattice structure used in the present invention is one that hardly expands despite the temperature rise due to the impact of an electron beam.
The closer the thermal expansion coefficient is to zero, the better. Specifically, Invar alloy (36Ni-Fe), super constant steel (32Ni-5Co)
−63Fe), stainless steel (54Co−9.5Cr−
36.5Fe), 43Pd-57Fe alloy, etc. can be used.

Further, in the present invention, the heat treatment performed after the cold rolling is performed to perform strain relief annealing to stabilize the {100} crystal plane. In addition, in the process of obtaining a thin plate by performing predetermined cold rolling and heat treatment, for example, after performing cold rolling multiple times at a rolling rate of 50% or less/one time, heat treatment may be performed at the end, or each cold rolling The operation of applying heat treatment after rolling can also be repeated multiple times.

〔Example〕

An example will be shown below in which a low thermal expansion alloy thin plate with excellent etching properties according to the present invention is used as a shadow mask thin plate for a color television.

Example 1 Melting an Invar alloy with a composition of 36% Ni-Fe,
The ingot was made into a wire rod with a radius of 6 mm through a continuous hot wire making process. A wire rod was forged at right angles to the longitudinal direction (thickness: 1 mm), then hot rolled at 900℃ to a thickness of 0.5 mm, and then cold rolled at a rolling rate of 30% to a thickness of 0.35 mm.
A thick thin plate was obtained, wound onto a roll, and subjected to strain annealing in vacuum at 550°C for 2 hours as heat treatment. Further, this thin plate was cold-rolled at a rolling ratio of 30% to form a thin plate with a thickness of 0.245 mm, and then heat-treated for strain relief annealing in the same manner. Such cold rolling and heat treatment operations were repeated several times to obtain a thin plate with a thickness of 0.1 mm.

In addition, when examining the surface condition after hot rolling in the above process by X-ray diffraction, it was found that 40% of {100} crystal planes were aggregated, and even after subsequent cold rolling and heat treatment, stable {100} crystals remained. The surface was maintained.

Based on the above formula, the collective state is f=∫ ² 〓/ ₀ ∫〓 ^/2 / ₀ I(φ, α) sinφcos ² φd
φ・dα／∫ ² 〓／ ₀ ∫〓 ^/2 ／ ₀ I (φ, α) sinφdφ・
dα- (I(φ, α): X-ray diffraction intensity at latitude angle φ and longitude angle α).

Next, the thin plate according to the present invention in which the {100} crystal planes were assembled by the method described above was used as a shadow mask original plate, and as a comparative example, the same hot rolling was performed, and then cold rolling was performed at a rolling rate of 80%/1 time. A comparison was made between a shadow mask original plate that had been subjected to rolling and heat treatment and an etching process for providing electron beam passage holes. In this comparative example, {110}
57% of the crystal faces are clustered, and 28% of the {100} crystal faces are
It was hot. In addition, etching can be performed using, for example, ferrous chloride 6.
Etching was performed at a temperature of 65°C using an aqueous solution containing 0.1% and 0.1% hydrochloric acid to form electron beam passage holes.

Note that the electron beam passage holes were formed into the shape shown in FIG. 2 by sequentially photoetching on both sides of the shadow mask original plate. The pitch of the electron beam passage hole is approx.
0.3mm, and approximately 520,000 electron beam passage holes were formed as a shadow mask for a 14-inch television. The electron beam passage holes on the surface of the shadow mask at this time were examined, and a mostly enlarged plan view of the mask according to the first embodiment is shown in FIG. 3, and a partially enlarged plan view of the mask according to the comparative example is shown in FIG. Note that 9 in the figure indicates an electron beam passage hole.

As is clear from these results, it is clear that electron beam passage holes are formed uniformly and with high precision in the shadow mask using the shadow mask original plate according to the present invention.

Example 2 In Example 1 above, the rolling ratio at one time during cold rolling was 20%, and the other conditions were the same, so that the {100} crystal plane was
A shadow mask original plate with 42% aggregation was produced. In this case as well, a good shadow mask could be obtained as in Example 1.

Example 3 After obtaining a thin plate with a thickness of 0.5 mm by forging and hot rolling in the same manner as in Example 1, one rolling rate of 8 was applied.
Using the so-called 20-high roll method, which repeats cold rolling several times, the material has a thickness of 0.1 mm and a {100} crystal plane of 43.
% aggregated shadow mask original plate was obtained.

Next, a heat treatment of strain relief annealing was performed at 550° C. for 2 hours, and then photoetching was performed in the same manner as in Example 1 to obtain a shadow mask. As a result, it was possible to obtain a highly accurate and uniform electron beam passage hole as shown in FIG.

〔Effect of the invention〕

As is clear from the above results, by using the manufacturing method of the present invention, it is possible to obtain a low thermal expansion alloy thin plate with excellent etching properties in which {100} crystal planes are assembled on the surface, and by photo-etching this thin plate, fine pores can be formed. can be provided uniformly with high density and precision. As a result, when the present invention is used for a shadow mask original plate, the pitch width can be reduced to about 1/3 compared to the conventional one, the number of electron beam passing holes can be increased by about 5 times, and it has low thermal expansion. Therefore, a high quality product without doming phenomenon etc. can be obtained.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the principle of a shadow mask tube, Fig. 2 is a sectional view showing an example of the shape of an electron beam passage hole, Fig. 3 is a partially enlarged plan view showing a shadow mask according to the present invention, and Fig. 4 is a conventional one. FIG. 3 is a partially enlarged plan view showing the shadow mask of FIG. 1...Shadow mask, 9...Electron beam passage hole.

Claims (1)

[Claims] 1. After forging an Invar type alloy having a face-centered cubic lattice structure, hot rolling is performed so that {100} crystal planes are formed on the rolled surface.
A method for producing a low thermal expansion alloy thin plate with excellent etching properties, comprising a step of aggregating 35% or more, and a step of cold rolling at a rolling rate not exceeding 50%/time and heat treatment for strain relief. . 2. A low thermal expansion alloy thin sheet with excellent etching properties, characterized by a collection of 35% or more {100} crystal planes on the surface of the thin sheet formed by an invar-type mold having a face-centered cubic lattice structure.