JPH0582017A - Original plate for shadow mask - Google Patents

Abstract

(57) [Summary] [Objective] In a shadow mask master plate made of a metal alloy such as amber alloy, variations in the diameter and shape of the holes formed by etching are eliminated, and unevenness occurs in the light transmitted through the aperture matrix. Try not to. [Structure] The relationship (X / X) between the total X of the distances x of the n concave portions existing in the arbitrary measurement length L of the original plate and the measurement length L.
Adjust L) x 100 to 0.8 or less. In addition, the specified length (500
(mm or more) one end of the original plate is fixed on the vertical plane, and the distance between the other end and the vertical plane is adjusted to 10% or less of the predetermined length.
Furthermore, the distance between the original plate of a specified length (500 mm or more) placed on the flat plate and the adjacent surface of the flat plate is adjusted to 5 mm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal original plate used in manufacturing a shadow mask for a color picture tube.

[0002]

2. Description of the Related Art In general, a shadow mask having a large number of apertures, which is formed in a matrix in accordance with a predetermined design standard, is arranged immediately in front of a fluorescent screen of a color picture tube. And with the demand for higher definition for color picture tubes, such shadow masks are also required to have higher precision, and the demands are becoming stricter year by year.
The electron beam emitted from the rear electron gun passes through the aperture of the shadow mask and irradiates the fluorescent dot at a predetermined position on the fluorescent screen to expose a color image, but the electron beam emitted at this time Not all of the electron beams pass through the aperture, and the electron beam that passes through the aperture is about 1/3 or less of the whole, and the rest of the electron beam directly hits the shadow mask to heat it. As a result, the shadow mask is thermally expanded and the positions of the openings are displaced from the design standard, which may cause a color shift phenomenon on the phosphor screen. Therefore, recently, Ni-Fe alloys with low thermal expansion properties, such as 36
Attempts have been made to prevent the color shift phenomenon by configuring the shadow mask itself with wt% Ni-Fe alloy (amber alloy).

By the way, when manufacturing a shadow mask from such a Ni-Fe alloy, first, a material block prepared by melting and casting with a predetermined alloy composition is forged by a conventional method,
Each process of rolling is performed to a predetermined thickness, and a slit is made into a required width dimension to obtain a master plate. Next, the opening positions of this original plate are etched to form electron beam transmission holes of a predetermined shape in a matrix. As an etching method,
First, apply photoresist to the original plate, dry it to form a resist film, and then place a working negative (negative) with a shadow mask pattern printed on a glass plate on the plate provided with the resist film and evacuate it. Make them adhere closely. Then, after irradiating light (UV light) from a mercury lamp or the like to expose the resist film to light, development, drying and baking are performed in this order, and then a hole is formed by corroding with an etching solution.

[0004]

However, the conventional
In the shadow mask original plate made of Ni-Fe alloy, etc., there is a large variation in the diameter and shape of the holes (electron beam transmission holes) formed by etching, which causes unevenness in light transmission through the holes. was there. Therefore, there has been a problem that it has not been possible to sufficiently meet the recent demand for higher definition in color picture tubes.

The present invention has been made in order to solve such a problem, and when an opening matrix is formed by etching, variations in hole diameter and hole shape hardly occur, and uneven transmission light occurs. It is an object of the present invention to provide a high-quality original plate for a shadow mask, which is capable of preventing the above.

[0006]

Means and Actions for Solving the Problems The inventors of the present invention have made extensive studies on the cause of the uneven etching in the shadow mask, and as a result, vacuum evacuation which is carried out to bring the negative film into close contact with the original plate on which the resist film is formed It was found that a gap is generated between the negative and the original plate when the ratio is insufficient, which causes variations in the hole diameter and the hole shape, which causes a decrease in the opening accuracy. The inventors have found that the vacuuming cannot be sufficiently performed due to the substantially wavy irregularities formed on the end face, the warpage of the entire original plate, or the lack of flatness, and the present invention has been completed.

That is, the first shadow mask base plate in the present invention is a metal base plate used for manufacturing a shadow mask, in which electron beam transmitting holes are formed.
With respect to a line connecting adjacent apexes of the substantially wavy uneven curve generated on the end face, x is a distance from the apex to the recess farthest from the apex, an arbitrary measurement length is L, and the measurement length is Assuming that the number of recesses existing in the space is n, the relation between the total X of the above n recesses x and the above L is (X / L) × 1
It is characterized by having a relationship of 00 ≦ 0.8.

A second shadow mask original plate according to the present invention has an electron beam transmitting hole formed in the same manner as described above, and one end of the metal original plate is a vertical plane when used for manufacturing a shadow mask. When fixed on the top, the distance between the other end set to a predetermined length and the vertical plane is 10% or less of the predetermined length.

Furthermore, the third shadow mask base plate in the present invention is a metal base plate used for manufacturing a shadow mask, in which electron beam transmitting holes are formed, and the metal base plate having a predetermined length is placed on a flat plate. When placed, the distance between the adjacent surfaces of the original metal plate and the flat plate is 5 mm or less.

The material constituting the original plate for the shadow mask of the present invention is not particularly limited, and various alloys can be applied, for example, Ni-Fe type alloy, Ni-Cr-Fe.
Examples include series alloys, Ni-Co-Fe series alloys, Ni-Co-Cr-Fe series alloys, and the like.

In the above-mentioned first invention, the sum X of the dent distances x of the n concave portions existing in the arbitrary measurement length L is X.
And the measurement length L is limited to the above range,
The reason is as follows. That is, when the value of (X / L) × 100 is larger than 0.8, the original plate and the negative cannot be sufficiently brought into close contact with each other even by vacuuming due to the unevenness of the end face, and the accuracy of opening is deteriorated. It causes unevenness. And
It is not possible to satisfy the recent demand for higher definition in color picture tubes. The smaller the value is, the smaller the unevenness is on the end face, which is preferable because the original plate and the negative can be sufficiently brought into close contact with each other. Note that here, if the measurement length L is small, the measurement error increases,
The value of L is preferably 2000 mm or more. further,
Even if the value of (X / L) × 100 is 0.8 or less, if only the recess distance x of one concave portion is extremely large, the vacuum suction adhesion of the negative becomes insufficient and etching unevenness occurs. All x values are preferably 3 mm or less.

As a method for adjusting the size, density, etc. of the wavy irregularities generated on the end face of the original plate within the above range, the following method is exemplified. That is, the cause of the wavy unevenness on the end surface is that when the alloy material is rolled to a predetermined plate thickness, the end portions are excessively rolled compared to the central portion, and annealing is performed while applying tension after rolling. Alternatively, by adopting a method such as inserting the original plate between rolls which are alternately combined while applying tension (tension leveler), it is possible to remove or prevent the wavy unevenness on the end face.

The second aspect of the present invention limits the degree of warpage of the entire original plate measured by the hanging method to a certain range. And, the distance between the one end fixed on the vertical plane and the other end hung from the vertical plane was limited to 10% or less of the length of the original plate. Can not absorb the warp,
This is because not only the adhesiveness between the original plate and the negative becomes insufficient, but also the edge of the negative may rub against the resist film of the warped original plate during vacuuming, and the resist film may be damaged. In addition, here, to measure the warp of the original plate with the hanging type,
This is to check the degree of warpage without the warp being reduced by the weight of the original plate. If the predetermined length for measuring the warp is too short, the length of the shadow mask will be significantly different from the actual size of the shadow mask and will not fit in the actual state. Therefore, the length is preferably 500 mm or more.

Furthermore, the third aspect of the invention limits the degree of twist, that is, the flatness of the entire original plate to a certain range. The distance between the end of a plate of a specified length placed on a flat plate and the upper surface of the flat plate is limited to 5 mm or less.If this exceeds 5 mm, the twist should be absorbed even by vacuuming. This is because the adhesiveness between the original plate and the negative is insufficient, which is not preferable. Here, the original plate is placed on the flat plate in order to measure the flatness that changes due to the own weight of the plate material while the own weight is applied. Further, if the predetermined length for measuring the flatness is too short in this way, it will be significantly different from the actual size of the shadow mask and will not fit in the actual state. Therefore, the length is preferably 500 mm or more. Furthermore, the larger the area of contact between the placed plate and the flat plate, the better.
It is sufficient if 50% or more is present.

In the above second and third inventions,
In order to adjust the warp or flatness of the original plate within the above range, for example, an original plate rolled to a predetermined thickness is inserted between rolls (levelers) that are alternately combined, or while applying tension to the original plate. It can be carried out by taking a method such as passing a leveler (tension leveler).

[0016]

EXAMPLES Examples of the present invention will be described below.

Example First, a 36 wt% Ni-Fe alloy of a predetermined composition, a so-called amber alloy, is melted, cast, and rolled in order to obtain a thickness of 0.25 mm.
A master plate for shadow mask of was produced. Since substantially wavy unevenness was generated on the end surface of this original plate, the wavy unevenness at both ends was almost completely removed through the tension leveler. After that, both ends were slit to obtain an original plate having a width of 600 mm.

The warpage and flatness of the obtained original plate were measured by the above-mentioned hanging type and flat plate placing type, respectively, and both were within the scope of the present invention.

For comparison, an original plate having a large number of substantially wavy irregularities on the end face as it was rolled was prepared, both ends thereof were slit, and the warpage and flatness were measured in the same manner as in the examples. .. The warpage and flatness of the original plate of Comparative Example were both outside the scope of the present invention.

Next, the respective original plates obtained in the above-mentioned Examples and Comparative Examples were etched as follows to open electron beam transmitting holes in a matrix form,
A shadow mask was manufactured. That is, first, the surface of the original plate was degreased, and then a photosensitive solution was applied to both surfaces to form a resist film. Next, a negative having large and small hole patterns was placed on the resist films on both surfaces, and the negative film was brought into close contact with the resist film by vacuuming. Then, the resist was exposed to light by an ultra-high pressure mercury lamp from behind the negative film. Then, after development, drying, and baking and curing, etching was performed using a ferric chloride solution to form electron beam transmission holes.

The shadow masks thus obtained were observed in the dark room with transmitted light to evaluate the unevenness quality. As a result, the shadow mask produced from the original plate of the example had the uniform electron beam transmission holes having the same diameter and shape, and had no unevenness. On the other hand, in the shadow mask manufactured from the original plate of the comparative example, the hole diameter and the hole shape were nonuniform, and the unevenness was clearly generated.

[0022]

As described above, in the shadow mask original plate of the present invention, the wavy unevenness, warpage or flatness generated on the end face is suppressed within an appropriate range. It is possible to obtain a high-quality shadow mask which is capable of sufficiently closely adhering to each other, has a small variation in hole diameter and shape due to etching, and has no unevenness. Therefore, a shadow mask which meets the design criteria and is excellent in performance can be obtained, and the recent demand for high definition of the color picture tube can be sufficiently satisfied, so that the industrial value is extremely great.

[0023]

Claims (3)

[Claims] 1. A metal original plate used for manufacturing a shadow mask having electron beam transmitting holes formed therein, wherein a top part of a substantially wavy concavo-convex curve formed on an end face is connected to a line connecting the adjacent top parts. Where x is the distance from the top line to the furthest concave portion, L is an arbitrary measurement length, and n is the number of concave portions existing between the measurement lengths, x of the n concave portions The relationship between the total X and the L is (X / L) × 1
A master plate for a shadow mask, which has a relationship of 00 ≦ 0.8. 2. A metal original plate having electron beam transmitting holes formed therein, which is used in manufacturing a shadow mask, wherein one end of the metal original plate is fixed on a vertical plane and the other end is set to a predetermined length. An original plate for a shadow mask, characterized in that the separation distance from the vertical plane is 10% or less of the predetermined length. 3. A metal original plate having electron beam transmitting holes formed therein, which is used when manufacturing a shadow mask, wherein when the metal original plate having a predetermined length is placed on a flat plate, the metal original plate and the flat plate are placed. An original plate for a shadow mask, characterized in that the distance between adjacent surfaces of is less than 5 mm.