JP2012238818A - Method for forming electrode by offset printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming electrodes by offset printing which enables a stripe-shaped line electrode having a width wider than that of a conventional one to be formed with good shape and dimensional accuracy by printing.SOLUTION: There is provided an electrode formation method for forming a stripe-shaped line electrode on a printing base material by offset printing including a doctoring step for scraping off excess conductive ink with a doctor knife after filling a plate with the conductive ink. As the plate for the offset printing, the plate is used which has a plurality of engraved portions 11 each having a concave shape in a concave pattern corresponding to the line electrode to be formed and filled with the conductive ink for the plate, and in which a ratio TS (%) of a total area of the engraved portions to an area of the line electrode to be formed is 70%≤TS<100% and an area S (μm) of each engraved portion satisfies 0<S≤80000 μm.

Description

  The present invention relates to an electrode forming method for forming striped line electrodes on a printing substrate by offset printing including a doctoring step of scraping excess conductive ink with a doctor knife after filling a plate with conductive ink. It is about.

  Conventionally, various electrode forming methods are known as an electrode forming method by printing to form electrodes on a printing substrate by printing, and as an example, an electrode forming method of a multilayer ceramic electronic component by gravure printing is known. (For example, refer to Patent Document 1).

  FIG. 7 is a diagram for explaining an example of gravure printing as an example of plate printing. In the example shown in FIG. 7, 51 is a conductive ink that is a material for forming an electrode, 52 is a plate engraved with a pattern 53 that is a recess filled with the conductive ink 51, 54 is a printing base material that is made of PET or the like, Reference numeral 55 denotes pressed copper. An example of gravure printing will be described with reference to FIG. 7. First, an inking process of filling the conductive ink 51 into the plate 52 on which the pattern 53 is engraved is performed, and then the printing base material is printed from the plate 52 using the pressed copper 55. A transfer step of transferring the conductive ink 51 to 54 is performed.

JP 2003-188044 A

  In the inking process described above, as shown in FIG. 7, a doctoring process is performed in which after the conductive ink 51 is filled into the pattern 53 formed of the concave portions of the plate 52, the excess conductive ink 51 is scraped off by the doctor knife 56. carry out. Conventionally, in plate printing that requires this doctoring process, it is not possible to form a wide stripe-shaped line, for example, a stripe-shaped line having a width of 300 μm or more on the printing substrate 54 without “missing”. was difficult. Here, “missing” means a state in which there is no conductive ink in the printed product where the conductive ink should originally exist, and corresponds to a disconnected state when an electrode circuit is assumed.

  The reason for the occurrence of this “missing” is considered to be that the blade edge of the doctor knife 56 falls into the concave portion of the pattern 53 in the plate 52 and scrapes up to a necessary amount of the conductive ink 51 during doctoring. .

  FIGS. 8A to 8D are diagrams for explaining “missing” in the conventional electrode forming method by plate printing. In the example shown in FIGS. 8A to 8D, first, as shown in FIG. 8A, after the conductive ink 51 is filled in the pattern 53 formed of the recesses, as shown in FIG. 8B. Then, a doctoring step of scraping off the excess conductive ink 51 with the doctor knife 56 is performed. In this case, if the width of the pattern 53 having a stripe-like line shape is wide, for example, if the width is 300 μm or more, the doctoring process is performed and the state shown in FIG. As shown in the cross section, the central portion of the conductive ink 51 filled in each pattern 53 is recessed. When printing (that is, transfer of the conductive ink 51 to the printing substrate 54) is performed in this state, the conductive ink 51 at the center of the line is removed as shown in FIG. End up. The omission defect at the center of the line changes according to the required line width, and the wider the line, the more prominent the defect state.

  An object of the present invention is to solve the above-described problems and to provide an electrode forming method by offset printing, which can form a stripe-shaped line electrode having a wider width than conventional ones by offset printing with high shape accuracy and dimensional accuracy. To do.

The electrode forming method by offset printing according to the present invention includes a striped line on a printing substrate by offset printing including a doctoring step of scraping excess conductive ink with a doctor knife after filling a plate with conductive ink. In an electrode forming method for forming an electrode,
As a plate used for the offset printing,
Corresponding to the line electrode to be formed, in the concave pattern filled with the conductive ink of the plate,
Each has a plurality of concave sculptures,
The ratio TS (%) of the total area of the engraving part to the area of the line electrode to be formed is
70% ≦ TS <100% and
The area S (μm ² ) of each engraving part is
Plate satisfying 0 <S ≦ 80000 μm ² ,
It is characterized by using.

  As a preferred example of the electrode forming method by offset printing of the present invention, the distance DI (μm) between the adjacent engraved portions is 0 <DI ≦ 20 μm, and the viscosity P (Pa · Pa) of the conductive ink. s) may be 1 ≦ P ≦ 50 Pa · s, and the electrode to be formed may be a striped line electrode in a passive drive display device.

According to the present invention, as a plate used for offset printing, each has a plurality of concave engraved portions, and the ratio TS (%) of the total area of the engraved portions to the area of the line electrode to be formed is 70% ≦ TS <100%, and the area of the individual engraved portion S ([mu] m ²⁾ is, 0 <S ≦ 80000μm ² in which the plate, with the use, to prevent the edge drop of a doctor knife, a conductive filled the plate In addition to preventing excessive scraping of the conductive ink, the space between adjacent engravings can be filled with the leveling action of the conductive ink, and offset printing enables wider line electrodes than conventional stripes to have shape accuracy and dimensional accuracy. An electrode forming method by offset printing that can be well formed can be obtained.

(A)-(c) is a figure which shows the process of an example of gravure offset printing as an example of offset printing used with the electrode formation method of this invention, respectively. (A), (b) is a figure for demonstrating an example of the plate pattern used with the conventional electrode formation method, respectively. (A), (b) is a figure for demonstrating an example of the plate pattern used with the electrode formation method of this invention, respectively. (A), (b) is a figure for demonstrating the other example of the plate pattern used with the electrode formation method of this invention, respectively. (A), (b) is a figure for demonstrating the further another example of the plate pattern used with the electrode formation method of this invention, respectively. (A), (b) is a figure which shows the structure of an example of the information display panel which uses the electrode produced according to the electrode formation method of this invention, respectively. It is a figure for demonstrating an example of gravure printing as an example of plate printing. (A)-(d) is a figure for demonstrating the "missing" in the electrode formation method by the conventional plate printing, respectively.

<About offset printing used for electrode formation in the present invention>
First, an example of offset printing used for electrode formation in the electrode forming method of the present invention will be described. FIGS. 1A to 1C are diagrams showing an example of gravure offset printing as an example of offset printing used in the electrode forming method of the present invention. In the example shown in FIGS. 1A to 1C, 1 is a conductive ink which is a material for forming an electrode, 2 is a plate engraved with a pattern 3 consisting of recesses filled with the conductive ink 1, and 4 is Si. Blanket rolls, 5 is a printing substrate made of PET, and 6 is pressed copper.

  An example of gravure offset printing will be described with reference to FIGS. 1A to 1C. The gravure offset printing method is roughly divided into three steps until printing on the printing substrate 5 is completed. Inking step (step of filling conductive ink 1 into plate 2 engraved with pattern 3): FIG. 2. Accepting step (receiving step of the conductive ink 1 from the plate 2 to the Si blanket roll 4): FIG. Transfer process (process of transferring the conductive ink 1 from the Si blanket roll 4 to the printing substrate 5): Each of the processes shown in FIG.

  In the inking process described above, as shown in FIG. 1A, after filling the conductive ink 51 into the pattern 53 formed of the concave portions of the plate 2, the doctor ring scrapes off the excess conductive ink 1 with the doctor knife 7. Perform the process. The feature of the electrode forming method of the present invention is to improve this doctoring process, and in particular to improve the pattern of the plate used.

<Regarding Plate Used for Offset Printing Characteristic of Electrode Forming Method of the Present Invention>
Next, referring to FIG. 2 (a), (b), FIG. 3 (a), (b), FIG. 4 (a), (b) and FIG. 5 (a), (b), A plate used for offset printing, which is a feature of the electrode forming method, will be described. Each of the examples shown in FIGS. 2A and 2B to FIGS. 5A and 5B shows one of the patterns 3 formed of the concave portions carved in the plate 2. Since the pattern 3 composed of the concave portions is formed on the surface of the cylindrical plate 2, it is actually concave, but here, the pattern 3 composed of the concave portions is described as a plane. FIGS. 2A and 2B show plates used in conventional offset printing, and FIGS. 3A and 3B to FIGS. 5A and 5B show the offset printing according to the present invention. Indicates the version to be used.

  In the plate used for the conventional offset printing shown in FIGS. 2A and 2B, the entire pattern 3 composed of recesses is formed from the recesses. In contrast, the plates used for offset printing of the present invention shown in FIGS. 3 (a), 3 (b), 4 (a), 4 (b) and 5 (a), 5 (b) each have a concave shape. It consists of a plurality of engraving parts 11. In the example shown in FIGS. 3A and 3B, the pattern 3 is formed by the internal rectangular engraving portion 11-1 and the triangular engraving portion 11-2 at the end. In the example shown in FIGS. 4A and 4B, the pattern 3 is formed by the triangular engraving portion 11. Furthermore, in the example shown in FIGS. 5A and 5B, the pattern 3 is formed by the circular engraving portion 11.

3A, FIG. 4A, and FIG. 5A, the plate 2 used in the offset printing of the present invention has an engraved portion 11 in which the gray portion is a concave portion (engraving portion) in any of the drawings. It corresponds. In the plate 2 used for offset printing of the present invention, in the plurality of engraving portions 11, (1) the ratio TS (%) of the total area of the engraving portion 11 to the area of the line electrode (corresponding to the pattern 3) to be formed is 70. % ≦ TS <100%, (2) it is necessary that the area of each engraving unit 11 S ([mu] m ²⁾ is 0 <S ≦ 80000μm ^2. The ratio TS (%) of the total area of the engraving portion 11 to the area of the line electrode (corresponding to the pattern 3) to be formed is preferably 80% ≦ TS <100%, and the area S ( [mu] m ²⁾ is preferably 650μm ² <S ≦ 40000μm ^2.

In the present invention, the reason why the ratio TS (%) of the total area of the engraving portion 11 to the area of the line electrode (corresponding to the pattern 3) to be formed is 70% ≦ TS <100% is that TS is less than 70%. This is because the total area of the unengraved parts with respect to the area of the line electrode to be formed increases and the engraved parts are not connected to each other. The reason why the area S of each engraved portion 11 ([mu] m ²⁾ and 0 <S ≦ 80000μm ^2, when S exceeds 800000Myuemu ^2, the cutting edge of the doctor knife 7 is depressed into the recess of the engraved portion 11, "omission This is because “

  Next, a preferred example of a plate used for offset printing, which is a feature of the electrode forming method of the present invention, will be described. First, a distance DI (μm) between adjacent engraved parts is preferably 0 <DI ≦ 20 μm, and more preferably 3 μm <DI ≦ 10 μm. As the distance DI between the engraving parts approaches 0, a print pattern without “missing” is obtained by the leveling action of the conductive ink, but 3 μm on the plate making is the limit that can be actually realized. Further, when the distance DI between the engraving parts exceeds 20 μm, the occurrence of “missing” may not be prevented by the leveling action. When the engraving part is circular, the distance DI between the engraving parts is the shortest distance between adjacent circles. Furthermore, the viscosity P (Pa · s) of the conductive ink is preferably 1 ≦ P ≦ 50 Pa · s. If the viscosity P is less than 1, the shape of the line may be disturbed because the viscosity is too low. On the other hand, when the viscosity P exceeds 50, the conductive ink may not be leveled due to high viscosity, and the engraved portions may not be connected. Furthermore, as for the shape of the engraving portion 11, in addition to the polygons and circles such as the triangle and quadrangle described above, an elliptical shape and the like can be selected as appropriate.

<About an information display panel using an electrode formed by the electrode forming method by offset printing of the present invention>
An example of an information display panel using, as a display medium, a particle group including a chargeable particle among information display panels to be used for electrodes formed according to the present invention will be described. In the information display panel, an electric field is applied to a display medium sealed in a space between two opposing substrates. Along with the applied electric field direction, the display medium is attracted by an electric field force or a Coulomb force, and the display medium is moved by a change in the electric field direction, whereby information such as an image is displayed. Therefore, it is necessary to design the display panel so that the display medium can move uniformly and maintain the stability when the display information is rewritten or when the display information is continuously displayed. Here, as the force applied to the particles constituting the display medium, in addition to the force attracting each other by the Coulomb force between the particles, an electric mirror image force between the electrode and the substrate, an intermolecular force, a liquid cross-linking force, gravity and the like can be considered.

  In the example shown in FIGS. 6A and 6B, at least two types of display media (here, the negatively charged white particles 23Wa are included) configured as a particle group including particles having at least optical reflectance and chargeability. A white display medium 23W configured as a particle group and a black display medium 23B configured as a particle group including positively chargeable black particles 23Ba) in each cell 27 formed by the partition wall 24, the panel substrate on the back side By applying a voltage between a pair of pixel electrodes formed by an electrode 25 (stripe electrode) provided on 21 and a transparent electrode 26 (stripe electrode) provided on a transparent panel substrate 22 on the observation side opposite to each other at right angles The substrate is moved perpendicularly to the substrates 21 and 22 in accordance with the generated electric field. Then, the white display medium 23W is visually recognized by the observer as shown in FIG. 6A, or the white display is displayed, or the black display medium 23B is visually recognized by the observer as shown in FIG. 6B. Is displayed in a matrix with black and white dots. In addition, in FIG. 6 (a), (b), the partition in front is abbreviate | omitted. Reference numeral 28 denotes an adhesive. Further, here, an example is shown in which cells and pixels (dots) have a one-to-one correspondence.

  In the information display panel described above, when the stripe electrodes 25 and 26 are formed, the electrode substrate forming method by offset printing of the present invention can be suitably used by using the panel substrates 21 and 22 as the printing base material 5.

  Hereinafter, although the specific Example and comparative example of the electrode formation method by offset printing of this invention are described, this invention is not limited to this.

<Example 1: An example in which the engraving portion has a quadrangular shape and a triangular shape (corresponding to FIGS. 3A and 3B)>
First, a printing plate was prepared as follows. That is, as shown below, a plate having a sculpture part shape was produced. The plate surface was subjected to Cr plating in order to prevent abrasion due to doctoring. The diameter of the plate was 200 mm.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Sculpture shape: Regular square with sides of 80 μm (line circumference is triangular)
Distance between sculpture parts: 5μm
Depth of sculpture part: 10μm

  Next, the conductive ink was adjusted as follows. Weigh 9 parts by weight of saturated copolymer polyester resin, 77 parts by weight of 1 μm silver fine particles, 5 parts by weight of 2-butoxyethyl acetate, and 9 parts by weight of 2- (2-ethoxyethoxy) ethyl acetate, and stir and disperse for 30 minutes. The conductive ink for printing was produced. The viscosity of the conductive ink was 25 Pa · s.

  Next, printing was performed as follows. The conductive ink was printed on the easy-adhesion surface of a PET film (Teijin: 03LF8) having an easy-adhesion layer by a gravure offset printing apparatus incorporating the above-mentioned plate, thereby forming a stripe-pattern conductive layer on the PET film. . The printing conditions were a printing speed of 1 m / min, a doctor angle of 50 °, and a doctor pressure of 0.2 MPa.

  Finally, the appearance of the stripe-patterned conductive layer obtained by printing was observed with a microscope (manufactured by Keyence Corporation), and the shape of the pattern (presence of “missing”, etc.) was evaluated. The case of a high-precision stripe pattern having no “missing” was marked with “◯”, and the case where a defect such as missing or disconnection was found was marked with “x”. The above criteria were also evaluated in the following examples and comparative examples. The results are shown in Table 1.

<Example 2: An example in which the engraving portion has a right isosceles triangle shape (corresponding to FIGS. 4A and 4B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving part shape was changed as follows. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Sculpture shape: right-angled isosceles triangle with a short side of 80 μm Distance between sculptures: 5 μm
Depth of sculpture part: 10μm

<Example 3: Example in which engraving part is circular (corresponding to FIGS. 5A and 5B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving part shape was changed as follows. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Engraved part shape: circular with a diameter of 80 μm Distance between engraved parts (shortest distance between adjacent engraved parts): 5 μm
Depth of sculpture part: 10μm

<Example 4: Example in which engraving part is square shape and triangular shape (corresponding to FIGS. 3A and 3B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving part shape was changed as follows. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Sculpture shape: Regular square with sides of 80 μm (line circumference is triangular)
Distance between sculptures: 10 μm
Depth of sculpture part: 10μm

<Example 5: An example in which the engraving part has a right isosceles triangle shape (corresponding to FIGS. 4A and 4B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving part shape was changed as follows. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Sculpture shape: Right-angled isosceles triangle with a short side of 35 μm Distance between sculptures: 3 μm
Depth of sculpture part: 10μm

<Example 6: Example in which engraving part is circular (corresponding to FIGS. 5A and 5B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving part shape was changed as follows. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Engraved part shape: circular with a diameter of 150 μm Distance between engraved parts (shortest distance between adjacent engraved parts): 10 μm
Depth of sculpture part: 10μm

<Comparative Example 1: Example in which engraving part is quadrangular and triangular (corresponding to FIGS. 3A and 3B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving part shape was changed as follows. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Sculpture shape: Regular square with sides of 300 μm (line periphery is triangular)
Distance between sculptures: 10 μm
Depth of sculpture part: 10μm

<Comparative Example 2: Example in which engraving part is quadrangular and triangular (corresponding to FIGS. 3A and 3B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving part shape was changed as follows. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Sculpture shape: Regular square with sides of 45 μm (line periphery is triangular)
Distance between sculptures: 10 μm
Depth of sculpture part: 10μm

<Comparative Example 3: Example in which engraving part is quadrangular and triangular (corresponding to FIGS. 3A and 3B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving part shape was changed as follows. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Sculpture shape: Regular square with sides of 20 μm (line circumference is triangular)
Distance between sculptures: 10 μm
Depth of sculpture part: 10μm

<Comparative Example 4: No engraving part (corresponding to FIGS. 2A and 2B)>
A conductive layer was formed and evaluated in the same manner as in Example 1 except that the engraving portion was not provided and the entire pattern was changed to a concave portion. The results are shown in Table 1.
Line shape: width 2.0mm, length (doctor knife sliding direction) 50mm
Spacing between adjacent lines: 100 μm
Total number of lines: 100 Sculpture shape: No Distance between sculptures: No Depth of sculpture at line: 10 μm

From the results of Table 1, each has a plurality of concave engraving parts, and the ratio TS (%) of the total area of the engraving parts to the area of the line electrode to be formed is 70% ≦ TS <100%. area of the engraved portion S (μm ²⁾ is examples 1 to 6 using is 0 <S ≦ 80000μm ² plate, as compared with Comparative examples 1 to 4 with other versions of, without "missing" It has been found that a conductive layer can be obtained.

  According to the present invention, it is possible to prevent the cutting edge of the doctor knife from falling into the plate concave portion, and the “leveling” with high shape accuracy and dimensional accuracy can be achieved even when printing a wide stripe-shaped electrode by ink leveling. It is possible to form a print pattern without “ Therefore, pattern formation with a line width of 2 mm, which was difficult with conventional printing, can be realized, and it is also possible to cope with a printed wiring board in which lines with a width of several μm to several mm are mixed at the same time.

DESCRIPTION OF SYMBOLS 1 Conductive ink 2 Version 3 Pattern 4 Si blanket roll 5 Printing base material 11 Base material 12 Anchor coat layer 13 Filler 21, 22 Panel substrate 23W White display medium 23Wa Negatively charged white particle 23B Black display medium 23Ba Positively charged black particle 24, 25 stripe electrode

Claims (4)

In an electrode forming method for forming a striped line electrode on a substrate for printing by offset printing including a doctoring step of scraping excess conductive ink with a doctor knife after filling a plate with conductive ink,
As a plate used for the offset printing,
Corresponding to the line electrode to be formed, in the concave pattern filled with the conductive ink of the plate,
Each has a plurality of concave sculptures,
The ratio TS (%) of the total area of the engraving part to the area of the line electrode to be formed is
70% ≦ TS <100% and
The area S (μm ² ) of each engraving part is
Plate satisfying 0 <S ≦ 80000 μm ² ,
An electrode forming method by offset printing, characterized in that The distance DI (μm) between the engraving parts adjacent to each other is
0 <DI ≦ 20 μm,
The electrode forming method by offset printing according to claim 1. The viscosity P (Pa · s) of the conductive ink is
1 ≦ P ≦ 50 Pa · s,
The electrode forming method by offset printing according to claim 1 or 2.   The electrode forming method according to any one of claims 1 to 3, wherein the electrode to be formed is a striped line electrode in a passive drive type display device.

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