JP3155782B2 - Original plate for shadow mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a metal original plate used for producing the shadow mask of the 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 according to a predetermined design standard, is provided immediately before a phosphor screen of a color picture tube. With the demand for higher definition of the color picture tube, higher precision is also required for such a shadow mask, and the demand is increasing year by year.

Normally, an electron beam emitted from a rear electron gun passes through an opening in a shadow mask and irradiates a fluorescent dot at a predetermined position on a fluorescent screen to cause a color image to appear there. Not all of the emitted electron beam passes through the aperture, and the electron beam passing through the aperture is less than about 1/3 of the whole, and the remaining electron beam hits the shadow mask and heats it . As a result, the shadow mask thermally expands and the position of the opening is displaced from the design standard, which may cause a color shift phenomenon on the phosphor screen. Therefore, recently, Ni-
Attempts have been made to configure the shadow mask itself with an Fe-based alloy, for example, a 36 wt% Ni-Fe alloy (amber alloy) to prevent the color shift phenomenon.

[0004] When a shadow mask is manufactured from such a Ni-Fe-based alloy, first, a material block adjusted to a predetermined alloy composition and melt-cast is subjected to various processes such as forging, rolling, and annealing by a conventional method. To a predetermined thickness, and slit to a required width to obtain an original plate. Next, the opening positions of the original plate are etched to form electron beam transmitting holes of a predetermined shape in a matrix. As an etching method, first, a photoresist is applied to an original plate, dried, a resist film is formed, a working negative (negative) on which a pattern of a shadow mask is baked is placed on a plate provided with the resist film, and vacuum is drawn. To adhere. Next, after irradiating light (UV light) with a mercury lamp or the like to expose the resist, development, drying, and baking are sequentially performed.
A method of corroding and drilling with an etchant has been adopted.
Furthermore, in the shadow mask that has been etched in this way, annealing is performed to improve press formability.

[0005]

SUMMARY OF THE INVENTION However, the conventional
In a shadow mask original plate made of a Ni-Fe alloy or the like, the diameter and shape of the openings (electron beam transmission holes) formed by etching are likely to vary, and unevenness may occur when light is transmitted through the openings. However, there was a drawback in that For this reason, there has been a problem that it is not possible to sufficiently meet the recent demand for higher definition in a color picture tube.

In general, annealing after etching is performed by stacking a plurality of original sheets, but there is a problem that the original sheets are liable to burn during this annealing.

[0007] The present invention has been made in order to cope with such a conventional problem, purpose of the present invention, when forming an opening matrix by etching, variations occur pore size and pore geometry it can be prevented that, and to provide a high quality of the original sheet for a shadow mask that does not occur seizure in annealing step after the etching.

[0008]

The inventors of the present invention have repeatedly studied the causes of the above-mentioned uneven etching, and as a result, when the surface condition of the original plate is greatly affected and the surface condition is inappropriate, the original plate is It has been found that the adhesiveness of the resist film formed thereon is insufficient, the resist film is peeled off at the time of etching, and side etching is caused by this, resulting in variations in the hole diameter and hole shape. In addition, when the surface condition of the original plate is inappropriate, the surface condition of the original plate affects the resist film thereon, so that the evacuation performed for bringing the negative into close contact becomes insufficient, and Gaps are formed between them, and
It has been found that image sticking occurs due to the fact that a plurality of plates are stacked, which is a cause of lowering the hole opening accuracy.

[0009]

The original plate for a shadow mask according to the present invention has been made based on the above-mentioned findings, and has an electron beam transmitting hole formed therein and a metal original plate used when manufacturing a shadow mask. , Its surface is
The center line average roughness Ra is more than 0.3 μm and 1 μm or less,
The average roughness Sm of the unevenness of the surface roughness is less than 70 μm, and the average inclination angle Δq of the convex portion of the surface roughness is 2 degrees or more and 10 degrees or less. In addition, the chassis of the present invention
The original plate for the dough mask is formed with electron beam transmission holes,
Smell of metal plate used in manufacturing the mask
The surface has a center line average roughness Ra exceeding 0.3 μm.
Is less than 1 μm, and the average distance Sm between the irregularities of the surface roughness is 10
0 μm or less, average inclination angle Δq of convex portion with surface roughness is 2 degrees or more
10 degrees or less and relative skewness of surface roughness (R
sk) is a positive value.

[0010]

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 alloys, Ni-Cr-Fe
Alloys, Ni-Co-Fe alloys, Ni-Co-Cr-Fe alloys, and the like.

In the present invention, the surface roughness of an original plate made of such an alloy is determined by measuring the center line average roughness Ra and the average interval Sm of irregularities according to JIS B 0601 (the average line of the cross-sectional curve within the reference length). The average value of the interval between the protruding projections) and the average inclination angle of the projections △ q (the root mean square inclination angle of the roughness curve)
It is specified by three parameters.

The reason why the center line average roughness Ra is limited to more than 0.3 μm and 1 μm or less is as follows. That is, when Ra is 0.3 μm or less, the adhesion of the resist film to the original plate is too weak, so that the side etching proceeds excessively, and the hole diameter and the hole shape are disturbed.
If a exceeds 1 μm, the adhesion of the resist film is too strong, so that the resist may remain in the portion to be perforated after development.

The reason why the average interval Sm of the unevenness is limited to 100 μm or less is that the pitch of the roughness is so large that
If m exceeds 100 μm, the adhesiveness of the resist film is locally weakened, and the side etching proceeds excessively at that portion, so that the hole shape is disturbed. When Sm is appropriately small, the adhesiveness of the resist film becomes uniform at any part of the hole, and the shape of the hole is not disturbed. like this
By setting the average interval Sm of the unevenness to less than 70 μm,
Producing a good shadow mask with less unevenness
it can. In particular, when etching at a high temperature or when manufacturing a high-precision mask having a small hole diameter, Sm is desirably 50 μm or less.

Furthermore, the reason why the inclination angle Δq of the projection is in the range of 2 to 10 degrees is that if Δq is less than 2 degrees, the adhesion of the resist film is too weak, so that the side etching proceeds too much and the hole diameter and hole If the shape is disturbed and Δq exceeds 10 degrees, on the other hand, the adhesiveness of the resist film is too strong, so that the resist may remain in a portion to be perforated after development . Further, in the original plate for a shadow mask of the present invention, in order to more effectively prevent image sticking in the annealing step after etching, the value of relativeness (skewness Rsk), which is another parameter indicating surface roughness, is positive. It is preferred that

The original plate for a shadow mask of the present invention can be manufactured, for example, as follows. That is, first, a predetermined amount of each component metal such as Ni and Fe is blended and melted so that a desired composition is obtained, and an alloy lump is cast. Then, the obtained alloy ingot is subjected to various processes such as forging, rolling, annealing, etc., to obtain an original plate having a predetermined thickness (usually 0.1 mm to 0.3 mm). Is applied. That is, finishing is performed using a rolling roll having an arbitrary surface state, and the unevenness of the roll surface is transferred to the original plate surface. With this, Ra and Sm can be set within the range of the present invention, and △ q and Rsk can be set to appropriate values.

[0017]

Embodiments of the present invention will be described below.

Examples 1 to 5 First, a 36 wt% Ni-Fe alloy, a so-called invar alloy, composed of a predetermined component was melted and cast, and then hot-rolled, cold-rolled,
Annealing etc. were performed in order to obtain a 0.25 mm thick original sheet, and dull finishing was performed in the final rolling process.
Was adjusted as shown in FIG.

Further, as a comparison with the present invention, except omitting the final dull finishing in the same manner, to prepare the original plate for Shah Douma disk. Table 1 also shows these surface roughnesses.

Next, after degreasing of the resulting respective Shah Douma disk original plate surface, thereby forming a respective resist film by applying a photosensitive solution on both sides. Next, a negative having a large and small hole pattern was placed on the resist film on both sides, and the resist was exposed to light by applying an ultra-high pressure mercury lamp from behind the negative after evacuation and close contact. Thereafter, after development, drying and baking hardening, etching was performed using a ferric chloride solution to form electron beam transmitting holes.

The thus manufactured shadow mask was observed in a dark room with transmitted light to evaluate unevenness. Table 1 shows the results. In addition, the quality of the unevenness is as follows: A having no unevenness and having particularly good quality; B having little unevenness and having good quality; C having little unevenness but having no practical problem; Those were designated as D.

[0022]

[Table 1]

As can be seen from Table 1, the original plate for the shadow mask according to each of the embodiments has the surface roughness Ra, the average interval Sm of the unevenness of the surface roughness, and the average inclination angle Δq of the projections all within an appropriate range. , A good shadow mask without unevenness is obtained. Also, no seizure occurred in the annealing step after the etching. The skew
Ness Rsk was positive in all the examples.

On the other hand, each original plate of the comparative example has Ra, S
Since at least one parameter out of m and Δq is out of the range of the present invention, the obtained shadow mask was so uneven that it could not be put to practical use.

[0025]

As described above, according to the master plate for a shadow mask of the present invention, since it has an appropriate surface roughness, variations in hole diameter and hole shape are reduced, and therefore, high quality without unevenness is obtained. Shadow mask can be obtained. Therefore, it is possible to obtain a shadow mask having excellent performance that conforms to the design standards, sufficiently satisfy the recent demand for higher definition of a color picture tube, and cause burn-in in an annealing process after etching. Since there is no such value, the industrial value is extremely large.

[0026]

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-253784 (JP, A) JP-A-4-103744 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 9/14 H01J 29/07

Claims (2)

(57) [Claims] 1. A metal original plate having an electron beam transmitting hole formed therein and used for manufacturing a shadow mask, the surface of which has a center line average roughness Ra of more than 0.3 μm and 1 μm or less, and a surface roughness of The average spacing Sm of the irregularities is 70 μm
An original plate for a shadow mask, wherein the average inclination angle Δq of the projections having a surface roughness of less than 2 degrees and not more than 10 degrees. 2. A metal plate having an electron beam transmitting hole formed therein and used for manufacturing a shadow mask, the surface of which has a center line average roughness Ra of more than 0.3 μm and 1 μm or less, and a surface roughness of The average spacing Sm of the irregularities is 100μ
m or less, and the average inclination angle Δq of the convex portion of the surface roughness is 2 degrees or more and 1 or more.
0 degrees or less and relative skewness of surface roughness (Rsk)
An original plate for a shadow mask, characterized in that the value of is positive.