TWI706865B - Screen board for printing - Google Patents

Abstract

A screen board for printing is disclosed. The screen board includes a frame and a screen fixed to the frame in a tension force of 23.5-39.5 N/cm. The screen has a plurality of meshes with an oblique angle of 35±l0 degree. The surface of the screen is smeared with a high polymer emulsion. The threads of the screen have a dimensional stability of 0.10 mm. The threads of the screen are plated with nickel. Each thread has a thickness of 3μm. The thickness of the high polymer emulsion can be reduced to 8±2μm, or replaced with the G65C type emulsion. The number of the meshes can be reduced to 250, with the thread diameter being increased as 30μm.

Description

Printing screen

The present invention relates to a printing screen, especially a printing screen capable of extending the service life of the screen and/or increasing the printing thickness.

FIG. 1 shows a schematic side view of a pattern printed on a circuit substrate (substract) B of a conventional printing screen 9. The printing screen 9 has a screen frame 91 and a mesh cloth 92, and the mesh cloth 92 is coated with a polymer emulsion 93. The mesh cloth 92 is fixed on the screen frame 91 with a single force, and is interwoven by multiple line segments to form several meshes. Accordingly, a squeegee 94 pushes the ink 95 in one direction, so that the ink passes through the mesh 92 to form a printing pattern. The polymer emulsion 93 is used as a liner to define the boundary of the pattern.

Please refer to Figure 2, which shows the specifications of the mesh 92. The name of the mesh 92 is ASADA-BS-325/28, made of steel wire, thickness is 55μm, wire diameter D is 28μm, mesh number M is 325mesh, mesh opening O size is 50μm, and aperture ratio (OPA) is 41 %. The calculation formula for the above parameters is M=1 inch/(D+O), and the aperture ratio (OPA)=( O /( O + D )) ² x100%. Mesh opening (MP) = (25400/mesh) minus wire diameter D. In the example in Figure 2, 1 inch=2.54cm=25400μm, mesh number M=25400/(28+50)=325(mesh), aperture ratio (OPA)=(50/(50+28)) ² x100%=41%.

According to the above-mentioned structure, the applied ink will be as shown in Fig. 3a, with the central part C of the ink showing a thinner thickness, and the edge part E of the ink showing a thicker thickness. In this way, Excessively thick edges may affect the Anisotropic Conductive Film (Anisotropic Conductive Film) package, resulting in poor bonding or accumulation of ACF particles and short circuits, as shown in Figure 3b.

Furthermore, the mesh of the aforementioned mesh cloth 92 is usually not coated with a protective material, so the durability is low.

In view of this, there is a need for an improved printing screen that can improve the thickness difference between the edge of the ink and the center of the ink, while extending the service life of the screen and increasing the stability of the printing size.

In order to solve the above problems, the object of the present invention is to provide a printing screen which has a longer service life and can increase the printing thickness.

The second objective of the present invention is to provide a printing screen, which can prevent the printed circuit board from being poorly bonded or causing short circuits due to the accumulation of particles of the conductive film in different directions.

The directionality described in the full text of the present invention or its similar terms, such as "front", "rear", "left", "right", "up (top)", "down (bottom)", "inner", "outer" , "Side", etc., mainly refer to the directions of the attached drawings. The directional or similar terms are only used to help explain and understand the embodiments of the present invention, and are not used to limit the present invention.

The elements and components described in the full text of the present invention use the quantifiers "one" or "one" for convenience and to provide the general meaning of the scope of the present invention; the present invention should be interpreted as including one or at least one, and single The concept of also includes the plural, unless it clearly implies other meanings.

The printing screen of the present invention includes a screen frame and a screen cloth. The mesh cloth is fixed on the screen frame with a tension of 23.5~39.5 Newton/cm, and has several meshes with a deflection angle of 35±10 degrees. One surface of the mesh is coated with a polymer emulsion, and the printing size of the mesh of the mesh is stable at ±0.10 mm, where the polymer emulsion is G60 with a thickness of 20±3μm, the surface of the wire mesh of the mesh is plated with nickel, and the thickness of the nickel is 3μm.

Accordingly, the durability of the printing screen can be improved by nickel plating on the mesh, thereby extending the life of the printing screen, and the boundary of the pattern can also be defined by the polymer emulsion.

In another embodiment, the printing screen of the present invention includes a screen frame and a screen cloth. The mesh cloth is fixed on the screen frame with a tension of 23.5~39.5 Newton/cm, and has several meshes with a deflection angle of 35±10 degrees. One surface of the mesh is coated with a polymer emulsion, and the printing size of the mesh of the mesh is stable at ±0.10 mm. The polymer emulsion is G60, and its thickness is 8±2μm.

Accordingly, the printing screen can reduce the thickness difference between the center part and the edge part of the solder resist film of the printed circuit board by reducing the coating thickness of the polymer emulsion, thereby avoiding affecting the packaging of the conductive film in different directions. And to avoid short-circuit due to poor bonding or accumulation of particles in the conductive film in different directions.

In another embodiment, the printing screen of the present invention includes a screen frame and a screen cloth. The mesh cloth is fixed on the screen frame with a tension of 23.5~39.5 Newton/cm, and has several meshes with a deflection angle of 35±10 degrees. One surface of the mesh is coated with a polymer emulsion, and the printing size of the mesh of the mesh is stable at ±0.10 mm. The polymer emulsion is G65C, and its thickness is 8±2μm.

Accordingly, the printing screen can be improved by changing the type of the polymer emulsion, thereby increasing the durability of the printing screen.

Among them, the mesh cloth is a 3D mesh cloth, the number of meshes is 325, and the wire diameter of the wire mesh of the mesh cloth is 28.

In still another embodiment, the printing screen of the present invention includes a screen frame and a screen cloth. The mesh cloth is fixed on the screen frame with a tension of 23.5~39.5 Newton/cm, and has several meshes with a deflection angle of 35±10 degrees. One surface of the mesh is coated with a polymer emulsion, and the printing size of the mesh of the mesh is stable at ±0.10 mm. The mesh is a 3D mesh, the number of grids is 250, the wire of the mesh The diameter is 30μm.

Accordingly, the printing screen can increase the printing thickness by increasing the diameter of the screen of the mesh and reducing the number of meshes.

In summary, by adjusting various parameters of the printing screen, the present invention can prolong the life of the printing screen and increase the printing thickness of the circuit substrate, so that the printing screen of the present invention has better use benefits. And better printing effect.

〔this invention〕

1: Screen frame

2: Mesh

3: Polymer emulsion

4: Printing ink area

B: Circuit board

C: The center of the solder mask

D: wire diameter

E: Edge of solder mask

SR: Solder mask

[Traditional]

9: Printing screen

91: net frame

92: Mesh

93: polymer emulsion

94: Scraper

95: ink

D: Wire diameter

O: Mesh opening

[Figure 1] A schematic diagram of the use of a conventional printing screen.

[Figure 2] A schematic diagram of the mesh of the conventional printing screen.

[Figure 3a] A schematic diagram of the printing ink thickness of the conventional printing screen.

[Figure 3b] The schematic diagram of the different-directional conductive film package of the liquid crystal display circuit substrate printed by the conventional printing screen.

[Figure 4a] A side view (1) of a printing screen of a preferred embodiment of the present invention.

[Figure 4b] The side view (2) of the printing screen of the preferred embodiment of the present invention.

[Figure 4c] This preferred embodiment of the present invention is a side view of a printing screen with a printing ink zone.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, the preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings:

Figures 4a and 4b show side views of the printing screen shown in a first embodiment of the present invention. The printing screen includes a screen frame 1 and a screen cloth 2. The mesh cloth 2 is a 3D mesh cloth and is coated with a polymer emulsion 3. The net cloth 2 is fixed to the net frame 1 with a single force, and is formed by a number of interwoven wire segments. Mesh items. The wire mesh of the mesh cloth 2 has a wire diameter D of 28 μm, and the mesh number is 325. The mesh cloth 2 can be fixed on the screen frame 1 with a tension of 23.5-39.5 Newton/cm, and the deflection angle of the wire mesh can be 35±10 degrees. The printing size of the screen of mesh 2 can be stable at ±0.10mm.

Accordingly, as shown in Figure 4c, the printing ink area 4 of the mesh cloth 2 can be passed by a squeegee (not shown), so that the ink passes through the mesh cloth 2 and is coated on the circuit substrate B below (shown in Figure 3a) Middle) On the surface, the printing of circuit board B is completed.

In this embodiment, the surface of the wire mesh of the mesh cloth 2 is plated with nickel, and the thickness of the nickel is 3 μm. In addition, the type of the polymer emulsion 3 is G60, and its coating thickness is 20±3 μm. Accordingly, compared with the conventional non-nickel-plated screen, the 3μm nickel-plated printing screen of this embodiment can increase its service life from 20000±1000 cycles to 25000±1000 cycles, which can improve the durability of the printing screen. effect.

In the above-mentioned first embodiment, when the printing screen is used to print a circuit board B (shown in Figure 3a), the thickness of the center part C of the solder resist film SR (Solder Resist) of the circuit board B is 10~12μm, and the thickness of the edge part E is 13~17μm. Accordingly, a second embodiment of the present invention is to reduce the coating thickness of the polymer emulsion 3 (G60) from 20±3μm to 8±2μm. As a result, the center of the solder resist film SR of the circuit board B The thickness of the part is reduced from 10~12μm to 6~8μm, and the thickness of the edge part is reduced from 13~17μm to 8~10μm. Therefore, the thickness difference between the center and the edge of the printed ink is reduced, thereby reducing the risk of poor bonding or short circuit due to accumulation of ACF particles.

In the above second embodiment, the life of the printing screen is 20000±1000 cycles. Accordingly, a third embodiment of the present invention is to change the polymer emulsion 3 from G60 to G65C, and the coating thickness is maintained at 8± 2μm. In this way, the use of G65C polymer emulsion 3 can increase the life of the printing screen from 20000±1000 cycles to 30000±1000 cycles, which has the effect of improving the durability of the printing screen.

In the first, second and third embodiments described above, the wire diameter D of the wire mesh of the mesh cloth 2 According to this, the fourth embodiment of the present invention increases the wire diameter D from 28μm to 30μm, reduces the mesh number from 325 to 250, and the polymer emulsion 3 is G65C, the coating thickness is 8±2μm. As a result, the life of the printing screen is maintained at 30000±1000 cycles, and when the printing screen is used to print a circuit board B (shown in Figure 3a), the solder resist film SR of the circuit board B The thickness of the center part is 8-9μm, and the thickness of the edge part is 9-11μm. In this way, the printed thickness of the circuit board B can be increased.

The above-mentioned first, second, third, and fourth embodiments of this case have different screen condition parameters and achievable effects, which are organized as Table 1 for clarification. In Table 1, when the screen type is "3D325-28", it means 3D screen is used. "325" means the number of meshes (mesh), and "28" means wire diameter D. In all the examples, it can be seen that when the screen type is "3D250-30", the surface of the screen is nickel-plated, the polymer emulsion is G65C, the polymer emulsion thickness is 8±2μm, the tension is 23.5-39.5, the deflection angle When it is 35±10 degrees, the best screen parameters can be obtained.

In summary, by adjusting various parameters of the printing screen, the present invention can prolong the life of the printing screen and increase the printing thickness of the circuit substrate, so that the printing screen of the present invention has better use benefits. And better printing effect.

Although the present invention has been disclosed using the above preferred embodiments, it is not intended to limit the present invention. Invention, any person who is familiar with this technique does not deviate from the spirit and scope of the present invention, and makes various changes and modifications relative to the above-mentioned embodiments still belong to the technical scope protected by the present invention. Therefore, the protection scope of the present invention shall be regarded as the attached application Those defined by the scope of the patent shall prevail.

1: Screen frame

2: Mesh

3: Polymer emulsion

4: Printing ink area

Claims (7)

A printing screen plate, comprising: a screen frame; and a screen cloth, fixed on the screen frame with a tension of 23.5~39.5 Newtons/cm, and having several screen meshes with a deflection angle of 35±10 degrees. One surface is coated with a polymer emulsion, and the printing size of the screen of the mesh is stable ±0.10mm. Among them, the polymer emulsion is G60 with a thickness of 20±3μm. The surface of the screen of the mesh Nickel plating, the thickness of nickel is 3μm. A printing screen plate, comprising: a screen frame; and a screen cloth, fixed on the screen frame with a tension of 23.5~39.5 Newtons/cm, and having several screen meshes with a deflection angle of 35±10 degrees. One surface is coated with a polymer emulsion, and the printing size of the screen of the mesh cloth is stable at ±0.10mm. Among them, the polymer emulsion is G60 and its thickness is 8±2μm. A printing screen plate, comprising: a screen frame; and a screen cloth, fixed on the screen frame with a tension of 23.5~39.5 Newtons/cm, and having several screen meshes with a deflection angle of 35±10 degrees. One surface is coated with a polymer emulsion, and the printing size of the screen of the mesh is stable at ±0.10mm. Among them, the polymer emulsion is G65C with a thickness of 8±2μm. For example, the printing screen of claim 2 or 3, wherein the surface of the screen of the mesh is plated with nickel, and the thickness of the nickel is 3 μm. For example, the printing screen of claim 1, 2 or 3, wherein the mesh is a 3D mesh, the number of grids is 325, and the diameter of the screen of the mesh is 28 μm. A printing screen, comprising: a screen frame; and a screen cloth, fixed on the screen frame with a tension of 23.5~39.5 Newton/cm, and having a deflection angle: Several meshes of 35±10 degrees, one surface of the mesh is coated with a polymer emulsion, and the printing size of the mesh of the mesh is stable at ±0.10mm. Among them, the mesh is a 3D mesh. The number is 250, and the wire diameter of the mesh of the mesh is 30 μm. Such as the printing screen of claim 6, wherein the polymer emulsion is G65C and its thickness is 8±2 μm.

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