KR101778884B1 - Methods for screen-printing having no moire - Google Patents

Abstract

According to the present invention, a screen printing method has an advantage of having a clear pattern and a beautiful movement by preventing moire when screen printing hair lines, dots, dot lines, etc. The screen printing method comprises the steps of: designing a pattern to print; outputting the pattern to a film; attaching the pattern-printed film to a direct film to which a coating solution is applied, and exposing the direct film; immersing the exposed direct film in a predetermined solution; developing the direct film; attaching the developed direct film to a screen plate; and applying ink to the screen plate to print.

Description

[0001] The present invention relates to a screen printing method for preventing moire from occurring,

The present invention relates to a screen printing method, and more particularly, to a screen printing method in which a moiré is not generated when screen printing a hair line, a dot, a dot line, or the like, will be.

Generally, screen printing is performed by forming a line portion and a non-line portion on a screen plate made of mesh or the like, placing a printing object (printing object) under the screen plate, And the ink is printed on the printing object through the wire guide.

Such screen printing has recently been widely used in electronic products. The hair line using screen printing and the repeated circular pattern (spin pattern) are used to give a beauty and luxury to buttons of window glass, washing machine and air conditioner of mobile phone, and a dot pattern (dot or dot Line and the like) are used for an LCD light guide plate and the like.

As shown in Fig. 1, the screen printing includes a step of designing a pattern (S10), a step of outputting a designed pattern to a film (S20), a step of applying a photosensitive emulsion to a screen plate made of mesh (S30) (Step S50) of washing the exposed screen plate with water (S50), placing the screen plate on the object to be printed (the printed body), and then removing the ink (Step S60).

On the other hand, instead of applying the photosensitive emulsion to the screen plate, the indirectly exposed photosensitive film may be attached to the screen plate as shown in FIG. 2 (S30 ').

However, when a pattern formed by a plurality of lines adjacent to each other like a hair line is formed by screen printing, there is a problem that moire occurs. Fig. 3 shows the pattern of the hairline. It can be seen that the moire 1 is repeated every predetermined angle. Patterns in which the moire 1 is frequently generated include continuous patterns of bending, patterns of repeated circular patterns (spin patterns), patterns of repeated curves, and patterns of a plurality of halftone dots.

The moire 1, which was not intended by the manufacturer, blurs the original shape of the pattern and hinders the formation of a beautiful pattern. In addition, when the circuit is made by screen printing, the line breaks due to the moire (1), so that the current may be cut off.

In order to solve this problem, it is possible to eliminate the moiré by increasing the interval between the lines. However, in this case, since the movement of the hairline pattern and the like disappears, There is a problem that it disappears.

Accordingly, there is a need for a screen printing method that can eliminate moiré while retaining the movement as it is.

On the other hand, due to the above-mentioned problem of screen printing, currently, patterns are formed on acrylic and glass beads by UV molding method. Particularly, a pattern is imprinted on a scattered film of a window glass of a smartphone by an UV molding method, and is completed by joining with a glass. However, such a UV molding method has a problem that it is difficult to ensure adhesion, heat resistance and durability, and the defective rate is high, so that the manufacturing cost is high.

As an alternative to the UV molding method, there is a method in which a photo film is adhered to a glass, or a photo-sensitizing solution is applied to a glass to expose it, and development is followed by hydrofluoric acid etching to implement a pattern directly on the glass. However, this method has a problem in that the manufacturing process is very complicated and many substances harmful to the human body and the environment are used.

The present invention has been proposed in order to solve the above-mentioned problems, and it is an object of the present invention to provide a printing method in which a moiré is not generated when screen printing a hair line, a dot, a dot line, It has its purpose.

It is still another object of the present invention to provide a method and apparatus for cleaning a substrate that does not use a toxic substance such as hydrofluoric acid, does not pollute the environment, is safe, and reduces a defective ratio without using a complicated manufacturing process required by a conventional UV molding method and a hydrofluoric acid etching method The present invention also provides a printing method capable of printing on a printing medium.

In order to solve the above problems, a screen printing method according to the present invention includes the steps of: (a) designing a pattern to be printed; (b) outputting the pattern to the film (10); (c) attaching and exposing the film (10) on which the pattern is output to the direct film (30) coated with the photosensitive liquid; (d) immersing the exposed direct film (30) in a predetermined solution; (e) developing the film 30 directly after the step (d); (f) attaching the developed direct film (30) to the screen plate (20); And (g) applying ink to the screen plate 20 and printing after the step (f).

As the predetermined solution, an aqueous hydrogen peroxide solution prepared by adding water to an aqueous solution of hydrogen peroxide of 28 wt% to 35 wt% can be used. Instead of the aqueous hydrogen peroxide solution, the A aqueous solution and the B aqueous solution of ULANO can be mixed and used. A aqueous solution is prepared by dissolving A powder in water, and aqueous B solution is prepared by dissolving B powder in water.

The step (e) includes the steps of: (e1) performing primary development using hot water at 40 to 60 ° C; And (e2) secondary development using cold water at 5 ° C to 25 ° C.

The pattern may be a pattern consisting of a plurality of lines of continuous bending, a pattern of repeated concentric circles, a pattern in which a plurality of curves are repeated, a pattern of a plurality of points, or a plurality of points, It can be a gradient pattern that gradually changes from one end to the other. Even when the distance between the lines, the radial distance of the concentric circles, the distance between the curves, or the distance between the points is 200 mu m or less, moire is not generated and the movement (phenomenon that different patterns are generated depending on the viewing angle) do.

The screen printing method according to the present invention has the following effects.

First, Moire is prevented from occurring when screen printing is performed on hair lines, dots, dot lines, etc., so that the pattern is clear and the movement becomes smooth, thereby resulting in an effect that the product becomes luxurious.

Second, it does not use toxic materials such as hydrofluoric acid, does not pollute environment, is safe, and can reduce defective ratio without using complicated manufacturing process required by conventional UV molding method and hydrofluoric acid etching method.

1 is a flow chart showing a screen printing method according to the prior art;
2 is a flow chart showing another screen printing method according to the prior art.
Fig. 3 is a diagram showing a hairline pattern made by screen printing according to the prior art; Fig.
4 is a flowchart showing a screen printing method according to a preferred embodiment of the present invention.
Fig. 5 is a drawing showing a pattern designed with CAD to be output to a film. Fig.
Fig. 6 is an enlarged view of a portion A in Fig. 5; Fig.
7 is a plan view showing a screen plate made of mesh.
8 is an enlarged view of a portion C in Fig.
9 is a view showing a part of a direct film after exposure.
10 is an enlarged view of a part of the screen plate;
Fig. 11 is an enlarged view of the direct film of Fig. 9 attached to the screen plate of Fig. 10; Fig.
FIG. 12 is an enlarged view of a screen line portion and a non-screening portion formed on a screen plate according to the screen printing method of FIG. 1 or FIG. 2;
13 is a view showing a pattern made up of a plurality of lines in which breaks are continuous.
14 is a view showing a pattern composed of a plurality of dots.
15 and 16 are photographs showing camera parts for mobile phones printed according to the present invention, respectively.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in the present specification and the configurations shown in the drawings are merely examples of the present invention and are not intended to represent all of the technical ideas of the present invention, so that various equivalents And variations are possible.

First, it is revealed that the screen printing method according to the present invention can be applied to various electronic parts, metals, glass, and the like. Therefore, the scope of the present invention should not be construed as being limited to a specific product.

4 is a flowchart showing a screen printing method according to a preferred embodiment of the present invention.

As shown in the drawing, the screen printing method includes steps of designing a pattern to be printed (S10), outputting the designed pattern to a film (S20), and transferring the pattern outputted from the pattern to a direct film (S140) of immersing the exposed direct film in an aqueous hydrogen peroxide solution (S140), and directly developing the film after the step (d) (S160) A step S170 of attaching the ink to the screen plate S180, a step S180 of drying the screen plate S170, and a step S190 of printing and injecting ink onto the screen plate S190.

Each of the above steps will be described below in order.

The step S10 (designing the pattern to be printed) may be performed by a computer graphic program, for example, an Auto CAD, a stirster, a cam, or the like. The step S20 (outputting the design pattern to the film) may be performed by a conventional method using a film used in conventional screen printing.

FIG. 5 shows that a hairline pattern designed by Auto CAD is output to a film, and FIG. 6 shows an enlarged view of part A of FIG. In Fig. 6, the portion 11 to which the pattern is output is displayed in black, and the portion 13 without the pattern is displayed in white.

For reference, some moirés shown in FIG. 5 are formed in the process of converting a hairline pattern designed by AutoCAD into a tiff file (picture file), which is not present in the actual designed pattern.

The hairline pattern is formed of a plurality of concentric circles. When the radial distance of the concentric circles is 200 μm or less, moire occurs as shown in FIG. 3 when printing is performed by the conventional screen printing method.

The film 10 on which the pattern is output is directly attached to the film and then exposed (S130). The direct film is coated with a sensitizing solution, and a film of ULANO can be used. When the direct film to which the pattern 10 is attached is exposed, the direct film portion corresponding to the pattern 11 outputting the pattern is not exposed. Therefore, the photosensitive liquid is not cured, Since the film portion is exposed, the photosensitive liquid is cured.

Subsequently, the exposed direct film is immersed in an aqueous hydrogen peroxide solution (S140), and the film is directly developed (S150) (S160).

The aqueous hydrogen peroxide solution is prepared by diluting 28 wt% to 35 wt% solution of hydrogen peroxide with water.

Instead of the aqueous hydrogen peroxide solution, the A aqueous solution and the B aqueous solution of ULANO can be mixed and used. The aqueous solution A is prepared by dissolving the A powder in water at 20 to 30 캜, and the aqueous solution B is prepared by dissolving the B powder in water at 20 to 30 캜. Since the A powder and the B powder are products of ULANO, they can be easily purchased in the market, and the description thereof will be omitted here.

Immersing the exposed direct film in the aqueous hydrogen peroxide solution or the AB mixed solution and developing it in water is intended to have adhesion force so that the direct film can be adhered to the screen plate. Therefore, if the adhesive force can be directly applied to the film, the hydrogen peroxide solution or another solution replacing the AB mixed solution may be used.

It is preferable that the above-mentioned phenomenon consists of a primary phenomenon in which hot water is sprayed on the direct film at 40 ° C to 60 ° C, and a secondary phenomenon in which cold water of 5 ° C to 25 ° C is sprayed to the direct film after the primary development.

Due to the immersion and development, the portion of the direct film corresponding to the portion 11 to which the pattern is output is perforated, and the portion of the direct film corresponding to the portion 13 to which the pattern is not output becomes the non-forming portion. 9 shows that the film 30 is directly pierced by the immersion and development, and the non-pierced portion (non-pierced portion, non-pierced portion) 33 is formed.

Next, the developed direct film 30 is attached to the screen plate 20 (S170) and the screen plate 20 is dried (S180). When the developed direct film 30 is placed on the screen plate 20 as shown in Fig. 10 as shown in Fig. 9, it is arranged as shown in Fig.

Fig. 11 shows a direct film 30 disposed on the screen plate 20. Fig. 11, the direct film 30 has already been developed and attached to the screen plate 20 in a state in which the straight line portion 31 and the non-straight line portion 33 are formed, and the ink passes through the straight line portion 31, It is printed on the print, and hence no moire occurs.

In the present invention, the warp portion 31 and the non-stripline portion 33 are formed irrespective of the inclination angle D of the screen mesh facts 21 and 23. That is, even if the inclination angle (D in FIG. 6) of the pattern is not coincident with the inclination angle (D) of the screen net facts 21 and 23, .

On the other hand, in the conventional screen printing, the light-sensitive emulsion is applied to the screen plate 20, or the indirect film is attached to the screen plate 20 and the film 10 is attached to the screen plate 20, A moiré is generated due to superimposition of the pattern of the screen mesh net 21 (23) and the film 10, and the moiré is reflected at the time of development, so that a moiré is reflected, City moire occurred.

In the conventional screen printing, if the inclination angle B of the pattern and the inclination angle D of the screen mesh facts 21 and 23 do not coincide with each other, Is formed stepwise along the halftone dot (an empty space between the mesh net and the mesh net), so that the printed pattern becomes unclear.

In the conventional screen printing, the hatched portion 31 and the non-hatched portion 33 are formed by the halftone dot (the square space formed by the net fact). The inclination angle B of the pattern and the screen net facts 21 and 23, Even if the inclination angles D of the lines 31 and 32 coincide with each other, the boundary between the line segments 31 and 33 does not coincide with the boundaries of the lines.

As shown above, the present invention can be applied to a hair line pattern (FIG. 5), a pattern consisting of a plurality of continuous lines (FIG. 13), a pattern in which a plurality of curves are repeated, It is possible to prevent moiré and print a clear pattern when a screen is printed with gradation patterns which are made up of dots and whose size or color gradually changes from one end to the other.

15 and 16 show camera parts for a mobile phone made according to the present invention, respectively. When screen printing is performed according to the present invention as shown in Figs. 15 and 16, moiré does not occur and a specific movement is clearly generated even if the interval between the lines and the interval between the points become 200 mu m or less.

1: moire 10: film with pattern printed
11: The pattern is printed 13: The pattern is not printed
20: Screen plates 21 and 23: Mens facts
30: direct film 31: Hwasunbu (chunghwa)
33: non-
B: Tilt angle of the pattern D: Tilt angle of the net fact

Claims (4)

A printing method for preventing a moiré pattern from occurring during screen printing,
(a) designing a pattern to be printed;
(b) outputting the pattern to the film (10);
(c) attaching and exposing the film (10) printed with the pattern to the direct film (30) coated with the photosensitive liquid;
(d) immersing the exposed direct film (30) in a predetermined solution;
(e) developing the film 30 directly after the step (d);
(f) attaching the developed direct film (30) to the screen plate (20); And
(g) applying ink to the screen plate (20) after the step (f) and printing the screen. The method according to claim 1,
The step (e)
(e1) a step of performing primary development using hot water at 40 to 60 DEG C; And
and (e2) secondary development using cold water at 5 DEG C to 25 DEG C. 5. A screen printing method for preventing generation of moire. 3. The method of claim 2,
The pattern may be a pattern consisting of a plurality of lines of continuous bending, a pattern of repeated concentric circles, a pattern in which a plurality of curves are repeated, a pattern of a plurality of points, or a plurality of points, A gradation pattern that gradually changes from one end to the other,
Wherein the distance between the lines or the radial distance or the distance between the curved lines or the distance between the centers of the concentric circles is 200 占 퐉 or less. 4. The method according to any one of claims 1 to 3,
Wherein the predetermined solution is an aqueous hydrogen peroxide solution.

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