JP6591508B2 - Method for forming insulating film by flexographic printing and flexographic printing plate - Google Patents

Description

  The present invention relates to a forming method for forming an insulating film by flexographic printing and a flexographic printing plate used for the forming method.

  In the formation of a film such as an insulating film or a conductor film, if a printing process can be used without using a vacuum process such as sputtering, an expensive film forming apparatus is unnecessary, cost can be reduced, and productivity is improved. Can be achieved.

  Patent Document 1 describes that a surface protective film (insulating film) covering an electrode pattern (conductive film) formed on a substrate is formed by flexographic printing on a substrate used in a liquid crystal device. 3 and 4 show how an insulating film is formed by flexographic printing described in Patent Document 1. In FIGS. 3 and 4, 11 shows a substrate, and 12 shows an electrode pattern (conductive film). . Reference numerals 13, 13a, and 13b respectively denote a coating film, a lower coating film, and an upper coating film formed by transferring and applying a liquid precursor for forming an insulating film.

  Patent Document 1 describes the following with reference to FIGS.

(1) When the liquid precursor is applied by flexographic printing, as shown in FIG. 3A, the vicinity of the edge 14 of the coating film 13 rises to a film thickness that is about twice the film thickness of the inner region. When the thickness is 1500 mm, cracks occur when cleaning or rubbing treatment is performed. Such cracks cause peeling of the coating film 13. In FIG. 3A, the limit is to form a surface protective film of 750 mm.

(2) As shown in FIG. 3B, after forming the lower coating film 13a by flexographic printing, the upper coating film 13b is formed again by flexographic printing, and then the upper coating film 13b and the lower coating film 13a are formed. When the curing method is adopted, when the bulge 16 near the edge 14 becomes about 2000 mm, cracks are generated in the subsequent cleaning or rubbing treatment. In FIG. 3B, the limit is to form a surface protective film of 1000 mm.

(3) As shown in FIG. 4A, a lower coating film 13a having a film thickness of about 650 mm is formed, and then an upper coating film 13b having a film thickness of about 650 mm is formed as shown in FIG. 4B. At this time, the upper coating film 13b is formed so that the edge 18 of the upper coating film 13b is positioned about 200 μm inside as viewed from the edge 14 of the lower coating film 13a. The swell 17 of the lower coating 13a and the swell 19 of the upper coating 13b do not overlap, and the location where the sum of the film thickness of the lower coating 13a and the upper coating 13b is the largest (the location where the swell 19 occurs) ), The film thickness is about 1950 mm, which is less than 2000 mm. Therefore, in FIGS. 4A and 4B, a surface protective film having a film thickness of 1300 mm can be formed. Since the film thickness of the portion where the bulge 19 is generated is only about 1950 mm, no crack is generated.

JP 2001-51259 A

As described above, in Patent Document 1, in the formation of an insulating film by flexographic printing, a crack is generated when the bulge generated at the edge of the insulating film becomes thick, and a thick insulating film is formed while avoiding the occurrence of the crack. For this reason, it is described that the insulating film is formed by coating twice by shifting the edge.

  By the way, the swell generated when the insulating film is formed by flexographic printing as described above occurs not only in the outer peripheral portion of the print pattern but also in the print pattern. For example, when there is a hole that is not printed in the print pattern (a blank where ink is not transferred), the swell also occurs around the hole.

  On the other hand, the insulating film is used as a surface protective film as described in Patent Document 1, and for example, there is a film formed between two conductor films. For example, the insulating film is formed between the two conductor films. When the insulating film has a through hole for connecting and conducting two conductor films, the printed pattern has a hole corresponding to the through hole, and therefore the insulating film around the through hole. Climax occurs.

  In order to connect two conductor films, in other words, when there is a bulge around the through hole of the insulating film used for conductor connection and the film thickness of the insulating film is increased, conductor connection failure is caused. . Hereinafter, this point will be described with reference to the drawings.

  FIG. 5A shows a schematic configuration for explanation, and a first conductor film 22, an insulating film 23, and a second conductor film 24 are sequentially laminated on a substrate 21. In FIG. 5A, reference numeral 25 denotes a through hole provided in the insulating film 23 for connecting the second conductor film 24 to the first conductor film 22.

  FIG. 5B shows a cross section of the through-hole 25 portion, and the film thickness of the insulating film 23 around the through-hole 25 is increased due to the bulge 23a of the insulating film 23, so that the second conductor film 24 has a large step difference. Since it is formed in a certain part, in FIG. 5B, the missing part occurs in the part surrounded by the broken line, that is, the connection is broken due to disconnection.

  On the other hand, FIG. 5C shows a cross section of the outer peripheral edge portion of the insulating film 23 located on the first conductor film 22. The bulge 23b of the insulating film 23 causes the insulating film 23 to bleed out, so that it protrudes from the position where the insulating film 23 is to be formed or the linearity of the edge of the insulating film 23 is impaired.

  In view of the above-described problems, an object of the present invention is to provide a forming method and a flexographic printing plate capable of preventing the occurrence of swell at the edge of a printing pattern in forming an insulating film by flexographic printing. is there.

According to the first aspect of the present invention, the insulating film is formed on the printing medium using the flexographic printing plate in which the halftone dots protrude from the convex portions defining the printing pattern and the ink of the insulating film material. In a method for forming an insulating film by flexographic printing, a halftone dot is composed of the number of lines and a halftone dot area ratio , and has a halftone dot condition capable of adjusting the ink holding amount , and the halftone dot area ratio is kept the same. This is a halftone dot with the characteristic that the ink holding amount decreases by changing the halftone dot condition to increase the number of lines , and the halftone dot condition is changed so that the ink holding amount is smaller than other areas on the convex part. The halftone dot condition changing region is provided in a portion corresponding to the edge of the print pattern, and the value of the number of lines in the halftone dot condition changing region is larger than the value in the other region.

  In the invention of claim 2, in the invention of claim 1, the value of the halftone dot area ratio in the halftone dot condition changing region is made equal to the value in the other region.

In the invention of claim 1 or 2 in the invention of claim 3, network Tenjo matter in halftone condition change region we are changed stepwise toward the edge of the print pattern in the interior of halftone condition change region.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the halftone dot condition changing region is provided at a portion corresponding to the trailing edge in the printing direction of the printing pattern.

  According to a fifth aspect of the present invention, in any one of the first to third aspects, the insulating film is an insulating film formed between two conductor films and has a through hole for connecting the two conductor films. The halftone dot condition changing region is an annular region provided at a portion corresponding to the edge around the through hole in the print pattern.

According to the invention of claim 6, in the flexographic printing plate in which halftone dots are projected and formed on the convex portions defining the printing pattern, the halftone dots are constituted by the number of lines and the halftone dot area ratio, and the ink holding amount is adjusted. halftone der having a characteristic of having a halftone condition, and the ink holding amount by a change of the halftone dots conditions to increase the number of lines while maintaining the dot percentage the same is reduced, which can be is, the convex A halftone dot condition changing area in which the halftone dot condition is changed so that the amount of ink retained is smaller than the other area on the part is provided at a portion corresponding to the edge of the print pattern, and the number of lines in the halftone dot condition changing area is The value of is made larger than the value in the other region.

  In the invention of claim 7, in the invention of claim 6, the value of the halftone dot area ratio in the halftone dot condition changing region is made equal to the value in the other region.

In the invention of claim 8 characterized in that in the invention of claim 6 or 7, the network Tenjo matter in halftone condition change area to that changed stepwise toward the edge of the print pattern in the interior of halftone condition change region Is done.

  According to a ninth aspect of the invention, in any of the sixth to eighth aspects of the invention, the halftone dot condition changing region is provided at a portion in contact with at least a part of the outer periphery of the convex portion.

  According to a tenth aspect of the present invention, in any one of the sixth to eighth aspects, the printing pattern has holes, and the halftone dot condition changing region is an annular region around the hole.

  According to the present invention, it is possible to prevent the film thickness from rising at the edge of the print pattern. Therefore, it is possible to prevent the phenomenon that the printed pattern edge is blurred due to the rise, and for example, when the insulating film formed between the two conductor films has a through hole for connecting the two conductor films In addition, it is possible to prevent the occurrence of such a phenomenon that connection failure occurs due to the rise of the insulating film around the through hole.

A is a figure for demonstrating the structure of the flexographic printing plate by this invention, B shows the through-hole part of an insulating film when the insulating film between two conductor films is printed and formed by the flexographic printing plate which has the structure of A. FIG. 4 is an enlarged cross-sectional view, and C is an enlarged cross-sectional view showing an outer peripheral edge portion when an insulating film is printed by a flexographic printing plate having a configuration of A. A is a top view which shows the outline | summary of the touchscreen with which the formation method of the insulating film by flexographic printing of this invention is applied, B is the elements on larger scale of A. FIG. A is a sectional view showing an edge portion of an insulating film formed by conventional flexographic printing, and B is a sectional view showing an edge portion of the insulating film formed by applying twice (overprinting) by conventional flexographic printing. A is a cross-sectional view showing an edge portion of an insulating film formed by conventional flexographic printing, and B is a cross-sectional view showing a state where the edge is shifted on A and the insulating film is overprinted by flexographic printing. A is a diagram showing a schematic configuration in which an insulating film having a through hole formed by flexographic printing is interposed between two conductor films, B is an enlarged cross-sectional view of a through hole portion of the insulating film in A, and C is The expanded sectional view of the outer periphery edge part of the insulating film in A. FIG.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1A shows the configuration of a flexographic printing plate according to the present invention. FIG. 1A shows only convex portions 31 that define a printing pattern of the flexographic printing plate, and halftone dots that are projected on the convex portions 31. Is not shown.

The convex portion 31 of the flexographic printing plate shown in FIG. 1A is for forming the insulating film 23 shown in FIG. 5A. In this example, the insulating film 23 such as polyimide, epoxy resin, or acrylic resin is insulated from the anilox roll. There are provided halftone dot condition changing regions 41 and 42 in which the halftone dot conditions for transferring the ink of the film material to the ink to be printed are changed with respect to other regions on the convex portion 31. In FIG. 1A, the halftone dot condition changing regions 41 and 42 are hatched.

  The halftone dot condition changing region 41 is provided as an annular region around the hole 32 of the print pattern corresponding to the through hole 25 (see FIG. 5A) formed in the insulating film 23, and the halftone dot condition changing region 42 is the pattern of the print pattern. The outer peripheral portion is provided over the entire circumference. In these halftone dot condition changing areas 41 and 42, the halftone dot conditions are selected so that the ink holding amount is smaller than the other areas (areas other than the halftone dot condition changing areas 41 and 42). In this example, the halftone dot condition in the halftone dot condition changing region 41 is further changed stepwise in a concentric manner in a ring-shaped region as will be described later. The width of the halftone dot condition changing regions 41 and 42 (width from the print pattern edge) is, for example, about 0.5 to 5 mm.

  FIGS. 1B and 1C use the flexographic printing plate provided with the halftone dot condition changing regions 41 and 42 as described above, and on the first conductive film 22 formed on the substrate 21 as in the configuration of FIG. 5A described above. The insulating film 23 is formed by flexographic printing, and when the second conductor film 24 is formed on the insulating film 23, the cross section of the through hole 25 portion of the insulating film 23 and the first conductor film 22 of the insulating film 23 are formed. The cross section of the outer peripheral edge part located on the top is each shown.

  By providing the halftone dot condition changing regions 41 and 42 with a reduced ink holding amount at a portion corresponding to the edge of the print pattern, it is possible to prevent the bulge of the insulating film 23 at the edge of the print pattern. By selecting each of them or changing them stepwise within the region, the edge shape of the insulating film 23 as shown in FIG. 1B and the edge shape of the insulating film 23 as shown in FIG. 1C can be obtained.

  In FIG. 1B, the bulge of the insulating film 23 is eliminated, and the insulating film 23 is formed so that the inner wall surface of the through hole 25 forms a gentle inclined surface toward the first conductor film 22, and therefore FIG. The second conductor film 24 can be satisfactorily formed without the occurrence of the omission as shown in (1), and the connection failure of the second conductor film 24 to the first conductor film 22 can be prevented.

  On the other hand, if the outer peripheral edge portion of the insulating film 23 has a shape that does not rise as shown in FIG. 1C, bleeding of the insulating film 23 can be suppressed.

  Here, the dot condition will be described. The halftone dot conditions include the number of lines and the halftone dot area ratio (percentage of halftone dots). By changing these values, the amount of ink retained (the amount of ink transferred to the printing medium) can be adjusted.

  As an example of specific numerical values, when the halftone dot condition of the flexographic printing plate forming the insulating film 23 is 300 LPI (line / inch) and the halftone dot area ratio is 70%, for example, the halftone dot condition of the halftone dot condition changing region 41 , 41a, 41b, 41c, and 41d in FIG. 1A that form the annular region are concentrically formed from the outside toward the inside, with the dot area ratio being 70%, stepwise from 400 LPI to 500 LPI to 600 LPI. Change. As a result, the amount of ink retained in the halftone dot condition changing region 41 can be reduced, and a gentle inclined surface can be formed on the edge of the insulating film 23.

  When the insulating film 23 is formed by flexographic printing, the rising of the printing pattern edge depends on the printing direction, and the rising is particularly noticeable at the trailing edge in the printing direction. In this regard, in FIG. 1A, the halftone dot condition changing region 42 is provided over the entire circumference of the outer periphery of the print pattern. The change area 42 may be provided. In this case, the halftone dot condition changing region 42 is provided only at a part of the portion in contact with the outer periphery of the protrusion 31. When the arrow a shown in FIG. 1A is the printing direction, the halftone dot condition changing region 42 is provided only on the right side 31 a side of the convex portion 31.

Further, the halftone dot conditions in each halftone dot condition changing region 41, 42 may be changed in consideration of the printing direction. For example, when the printing direction is the arrow a, the second conductor film 24 can be sufficiently connected to the first conductor film 22 by eliminating the bulge without forming an inclined surface on the inner wall surface of the through hole 25. For each side 41a, 41b, 41c, 41d of the halftone dot condition changing region 41 having a square frame shape, the halftone dot area ratio is the same 70%, and the number of lines is
41a: 600 LPI
41b: 500 LPI
41c, 41d: 400LPI
It is good.

  Further, the halftone dot conditions in each of the halftone dot condition changing regions 41 and 42 may be selected by combining stepwise changes in the region toward the edge of the print pattern and changing in consideration of the print direction. .

  The method for forming an insulating film by flexographic printing and the flexographic printing plate according to the present invention have been described above. Next, specific examples to which the present invention is applied will be described.

  FIG. 2 shows a capacitive touch panel to which the present invention is applied. The touch panel has a rectangular transparent substrate 50, extends on the transparent substrate 50 along the X direction parallel to the short side of the transparent substrate 50, and is arranged in parallel in the Y direction parallel to the long side of the transparent substrate 50. A plurality of first sensor electrode rows 61 and a plurality of second sensor electrode rows 62 extending in the Y direction and arranged in parallel in the X direction are formed.

  A lead wire 71 is drawn from one end of each first sensor electrode row 61, and a lead wire 72 is drawn from one end of each second sensor electrode 62. These lead wires 71 and 72 extend to a terminal portion 73 formed near the center of one short side of the transparent substrate 50.

  The first sensor electrode row 61 includes a plurality of island electrode portions 61a arranged in the X direction and a connecting portion 61b that connects adjacent island electrode portions 61a, and the second sensor electrode row 62 has a Y direction. And a plurality of island-shaped electrode portions 62a arranged in a row and a connecting portion 62b for connecting adjacent island-shaped electrode portions 62a.

  As shown in FIG. 2B, the touch panel has a configuration in which a first conductor film 81, an insulating film 82, a second conductor film 83, and a protective film 84 are sequentially stacked on the transparent substrate 50. The plurality of first sensor electrode rows 61, the lead wires 71 and 72, and the terminal portion 73 are formed by the first conductor film 81, and the plurality of second sensor electrode rows 62 are formed by the insulating film 82 and the first conductor film 81. And a second conductor film 83 insulated from each other. The first sensor electrode row 61 and the second sensor electrode row 62 intersect with each other in an insulated state, and the connecting portions 61b and 62b are positioned so as to overlap each other. In FIG. 2A, the outlines of the insulating film 82 and the protective film 84 are not shown.

  The connection between the second sensor electrode array 62 and the lead-out wiring 72 is made by the through-hole 91 portion by forming the through-hole 91 in the insulating film 82. As shown in FIG. 2A, the through hole 91 is provided in correspondence with the position where the island-like electrode portion 62a at the lower end in the Y direction of each second sensor electrode row 62 is located.

  FIG. 2B shows a cross-section of the through-hole 91 portion, and the insulating film 82 is formed by the method of forming an insulating film by flexographic printing according to the present invention and does not rise, and the inner wall surface of the through-hole 91 is gently inclined. Since they are formed so as to form a surface, connection failure does not occur, and the second sensor electrode array 62 and the lead-out wiring 72 can be satisfactorily connected. Therefore, productivity can be improved.

  Although not shown in detail in FIG. 2A, the first and second sensor electrode arrays 61 and 62, the lead wirings 71 and 72, and the terminal portion 73 are all made of a conductive fine wire mesh pattern and conductive such as silver. If the ink is formed by gravure offset printing, and if the insulating film 82 is formed by flexographic printing and the protective film 84 is also formed by flexographic printing as described above, the touch panel is manufactured by a printing process. Therefore, a significant cost reduction can be achieved.

DESCRIPTION OF SYMBOLS 11 Board | substrate 12 Electrode pattern 13 Coating film 13a Lower coating film 13b Upper coating film 14 Edge 15, 16, 17, 19 Swell 18 Edge 21 Substrate 22 First conductor film 23 Insulating film 23a, 23b Swell 24 Second Conductive film 25 Through-hole 31 Convex portion 31a Right side 32 Hole 41, 42 Halftone dot condition changing region 41a-41d Side 50 Substrate 61 First sensor electrode row 61a Island electrode portion 61b Connection portion 62 Second sensor electrode row 62a Island Electrode portion 62b connecting portions 71, 72 lead-out wiring 73 terminal portion 81 first conductor film 82 insulating film 83 second conductor film 84 protective film 91 through hole

Claims (10)

A method of forming an insulating film by flexographic printing, in which an insulating film is formed on a substrate by using a flexographic printing plate having halftone dots protruding on a convex portion that defines a printing pattern, and an insulating film material ink. There,
The halftone dot is composed of the number of lines and the halftone dot area ratio , and has a halftone dot condition capable of adjusting the ink holding amount , and increases the number of lines while maintaining the same halftone dot area ratio. halftone der having a characteristic amount the ink holding is reduced by a change in the dot condition which causes is,
A halftone dot condition changing region in which the halftone dot condition is changed so that the ink holding amount is smaller than the other area on the convex portion is provided at a portion corresponding to the edge of the print pattern,
The method for forming an insulating film by flexographic printing, wherein the value of the number of lines in the halftone dot condition changing region is larger than the value in the other region. In the formation method of the insulating film by flexographic printing of Claim 1,
The method of forming an insulating film by flexographic printing, wherein a value of the dot area ratio in the dot condition changing region is equal to a value in the other region. In the formation method of the insulating film by flexographic printing of Claim 1 or 2,
The method for forming an insulating film by flexographic printing, wherein the halftone dot condition in the halftone dot condition changing region is changed stepwise toward an edge of the print pattern inside the halftone dot condition changing region . In the formation method of the insulating film by flexographic printing in any one of Claim 1 to 3,
The method for forming an insulating film by flexographic printing, wherein the halftone dot condition changing region is provided at a portion corresponding to a trailing edge in a printing direction of the printing pattern. In the formation method of the insulating film by flexographic printing in any one of Claim 1 to 3,
The insulating film is an insulating film formed between two conductor films, and has a through hole for connecting the two conductor films.
The method of forming an insulating film by flexographic printing, wherein the halftone dot condition changing region is an annular region provided at a portion corresponding to an edge around the through hole in the printing pattern. A flexographic printing plate in which halftone dots are projected and formed on convex portions defining a printing pattern,
The halftone dot is composed of the number of lines and the halftone dot area ratio , and has a halftone dot condition capable of adjusting the ink holding amount , and increases the number of lines while maintaining the same halftone dot area ratio. halftone der having a characteristic amount the ink holding is reduced by a change in the dot condition which causes is,
A halftone dot condition changing region in which the halftone dot condition is changed so that the ink holding amount is smaller than the other area on the convex portion is provided at a portion corresponding to the edge of the print pattern,
The flexographic printing plate is characterized in that the value of the number of lines in the halftone dot condition changing region is larger than the value in the other region. In the flexographic printing plate according to claim 6,
The flexographic printing plate according to claim 1, wherein a value of the halftone dot area ratio in the halftone dot condition changing region is equal to a value in the other region. In the flexographic printing plate according to claim 6 or 7,
The flexographic printing plate according to claim 1, wherein the halftone dot condition in the halftone dot condition changing region is gradually changed toward the edge of the printing pattern inside the halftone dot condition changing region. In the flexographic printing plate according to any one of claims 6 to 8,
The flexographic printing plate is characterized in that the halftone dot condition changing region is provided in a portion in contact with at least part of the outer periphery of the convex portion. In the flexographic printing plate according to any one of claims 6 to 8,
The printed pattern has holes;
The flexographic printing plate, wherein the halftone dot condition changing region is an annular region around the hole.

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