KR20170066895A

KR20170066895A - Flexible printed circuit boards

Info

Publication number: KR20170066895A
Application number: KR1020150173108A
Authority: KR
Inventors: 박성빈; 김정규; 채원제; 임창균
Original assignee: 스템코 주식회사
Priority date: 2015-12-07
Filing date: 2015-12-07
Publication date: 2017-06-15
Also published as: KR101753688B1

Abstract

A flexible circuit board is provided. The flexible circuit board includes a base film, a plurality of via holes passing through the base film, an upper wiring formed on one surface of the base film, a lower wiring formed on the other surface of the base film, And a plurality of via pads formed to overlap with the plurality of via holes and electrically connecting the upper wiring and the lower wiring, wherein the base film has an inner side in a width direction or a longitudinal direction of the base film A plurality of via pads arranged in the first region, and a plurality of via pads arranged in the first region, the plurality of via pads being disposed in the first region so as to cover the via hole, A plurality of first via pads arranged in the second region and having an area larger than that of the first via pad, And a plurality of second via pads.

Description

[0001] FLEXIBLE PRINTED CIRCUIT BOARDS [0002]

The present invention relates to a flexible circuit board

Recently, flexible and thin flexible circuit boards have been used more than rigid circuit boards due to the thinness and shortening of electronic devices. The flexible circuit board may be formed by attaching a copper foil on a polyimide film.

As the size and complexity of electronic products have increased, the complexity of wiring of the flexible circuit board has increased. In order to increase the density of the wirings disposed on the flexible circuit board, wirings are disposed on both sides of the flexible circuit board, and structures interconnected with each other through the via holes are used.

Conventionally, wirings are formed only in regions where the via hole processing position accuracy is excellent for matching the via holes and the via pads corresponding to the via holes. That is, when a via hole is processed using a laser, the accuracy of the via hole processed through the edge of the lens can be lowered due to the physical characteristics of the lens controlling the laser sight path.

That is, the position of the via-hole formed in the edge region of the flexible circuit board may be biased to one side of the via pad so that the electrical characteristics may be deteriorated, or the via hole and the via pad may be displaced from each other. As a result, there is a problem that surplus area of the flexible circuit board exists because the edge area of such a flexible circuit board does not form a via hole.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wiring board having a high degree of integration and a flexible circuit board for preventing misalignment of via holes and via pads.

The technical objects of the present invention are not limited to the technical matters mentioned above, and other technical subjects not mentioned can be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, there is provided a flexible printed circuit board including a base film, a plurality of via holes passing through the base film, an upper wiring formed on one surface of the base film, And a plurality of via pads formed on the one surface and the other surface of the base film so as to overlap with the plurality of via holes and electrically connecting the upper wiring and the lower wiring, The film includes a first region including an inside in a width direction or a longitudinal direction of the base film and a second region including an outside in a width direction or a longitudinal direction of the base film, A plurality of first via pads arranged in the first region and having a predetermined area to cover the via hole, And a plurality of second via pads disposed in the first via pad and having an area larger than the area of the first via pad.

In some embodiments of the present invention, the width dimension or the width dimension of the second via pad may be 1.01 to 3 times the width dimension or the width dimension of the first via pad, respectively.

In some embodiments of the present invention, the width dimension or the width dimension of the second via pad may be 1.01 to 3 times the average width dimension or width dimension of the first via pad, respectively.

In some embodiments of the present invention, the width of the base film is 70 mm, and the width of the first region is 50 mm to 60 mm.

In some embodiments of the present invention, the base film may further include a sprocket hole formed along the longitudinal direction at an edge thereof.

In some embodiments of the present invention, the plurality of first via pads are formed by arranging a plurality of first pad groups aligned in an oblique diagonal direction with respect to the longitudinal direction and adjacent to each other, The plurality of second via pads may form a plurality of second pad groups aligned in the diagonal direction and adjacent to each other.

In some embodiments of the present invention, the first pad group includes n first via pads (where n is a natural number), and the second group includes m (where m is a natural number) smaller than n Second via pads.

In some embodiments of the present invention, the plurality of first pad groups includes a first via-hole group, and the first via-hole group includes the plurality of via-holes disposed on a straight line extending in the width direction Wherein the plurality of second pad groups includes a second via hole group and the second via hole group includes the plurality of via holes disposed on a straight line extending in the width direction, The hole group and the second via hole group may be arranged on the same line.

According to the flexible circuit board according to the embodiments of the present invention, the via pad, the wiring, and the via hole for connecting the via pad, the wiring and the via hole can be formed on the area located on the outer side of the flexible circuit board, thereby improving the circuit integration degree of the flexible circuit board .

In addition, by forming the via pad located on the region located on the outer side of the flexible circuit board larger than the via pad located on the inner region, it is possible to prevent the conduction failure of the wiring due to the manufacturing error of the via hole.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

1 is a side view of a display device including a flexible circuit board according to an embodiment of the present invention.
2 is a plan view of a flexible circuit board according to an embodiment of the present invention.
3 is a cross-sectional view taken along II and II-II in Fig.
4 is a cross-sectional view of a flexible circuit board according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. The dimensions and relative sizes of the components shown in the figures may be exaggerated for clarity of description. Like reference numerals refer to like elements throughout the specification and "and / or" include each and every combination of one or more of the mentioned items.

It is to be understood that when an element or layer is referred to as being "on" or " on "of another element or layer, All included. On the other hand, a device being referred to as "directly on" or "directly above" indicates that no other device or layer is interposed in between.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms should be understood to include, in addition to the orientation shown in the drawings, terms that include different orientations of the device during use or operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions. The elements can also be oriented in different directions, so that spatially relative terms can be interpreted according to orientation.

The terminology used herein is for the purpose of illustrating embodiments and is not intended to be limiting of the present invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. The terms " comprises "and / or" comprising "used in the specification do not exclude the presence or addition of one or more other elements in addition to the stated element.

Although the first, second, etc. are used to describe various elements or components, it is needless to say that these elements or components are not limited by these terms. These terms are used only to distinguish one element or component from another. Therefore, it is needless to say that the first element or the constituent element mentioned below may be the second element or constituent element within the technical spirit of the present invention.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise.

1 is a side view of a display device including a flexible circuit board according to an embodiment of the present invention.

Referring to FIG. 1, the display device may include a flexible circuit board 100, a display panel 200, a rigid circuit board 300, and a driving device 400.

The display panel 200 can display an image, and the hard substrate 300 can generate a signal for driving the display panel 200. The flexible circuit board 100 may electrically connect the rigid circuit board 300 and the display panel 200. The rigid circuit board 300 may be disposed below the display panel 200 to reduce the size of the display device and the flexible circuit board 100 may be bent in a curved shape to connect the rigid circuit board 300 and the display panel 200, Can be connected. The flexible circuit board 100 may be provided with pads for connection with the rigid circuit board 300 or the display panel 200 and the pads formed on the flexible circuit board 100 may be connected to the rigid circuit board 300 or the display panel 200. [ 200 and the anisotropic conductive film.

The driving element 400 may be disposed on the flexible circuit board 100. The driver 400 may be in the form of an integrated circuit (IC). When the driving element 400 is disposed on the flexible circuit board 100, the complexity of the wiring of the flexible circuit board 100 can be increased. According to some embodiments, the driving element 400 may not be disposed on the flexible circuit board 100 and may be disposed on the display panel 200 or on the rigid circuit board 300 It is possible.

FIG. 2 is a plan view of a flexible circuit board according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line I-I and II-II in FIG.

2 and 3, the flexible printed circuit board 100 includes a base film 50, upper via pads 10 and 20, lower via pads 30 and 40, upper wirings 11 and 21, Holes 31 and 41, and via holes VH1 and VH2.

The base film 50 may be formed of a flexible material and may be included as a base material on the flexible circuit board to bend or fold the flexible circuit board. The substrate may be, for example, a polyimide film. Alternatively, the base film may be a plastic film such as a PET film, a polyethylene naphthalate film, a polycarbonate film, or an insulating metal foil. In the flexible circuit board 100 according to an embodiment of the present invention, the base film is described as a polyimide film.

The base film 50 may include a first region IA and a second region EA1. The first area IA may be an area disposed on the inner side with respect to the width direction or the longitudinal direction of the flexible circuit board 100 and the second area EA1 may be a width direction of the flexible circuit board 100, As shown in Fig. The second region EA1 may include an end 110 of the base film 50. [ Therefore, the second region EA1 may include the edge of the base film 50. [

The first upper via pad 10 may be disposed on one side of the base film 50. The first upper via pad 10 may be disposed in the first region IA of the base film. The flexible circuit board 100 may include a plurality of first upper via pads 10.

The first upper via pad 10 may be disposed so as to overlap with the first via hole VH1. That is, the first upper via pad 10 may cover the first via hole VH1. The first upper via pad 10 may be connected to the first upper wiring 11. The first upper via pad 10 may have a shape in which the width of the first upper wiring 11 is extended in the first direction d1.

Here, the first direction (d1) may be the width direction of the base film (50). On the other hand, the third direction (d3) may be the longitudinal direction of the base film (50).

The first upper via pad 10 is formed to have an expanded width of the first upper wiring 11 so as to improve the connection between the first via hole VH1 and the wiring, It is possible to secure the electrical connection reliability of the via-hole VH1.

The first upper via pad 10 may be formed integrally with the first upper wiring 11. Each of the plurality of first upper via pads 10 may be in a rectangular shape, but is not limited thereto.

The plurality of first upper via pads 10 may be divided into a plurality of first pad groups PG1. The plurality of first upper via pads 10 included in each of the plurality of first pad groups PG1 may be connected to the plurality of first upper wirings 11 arranged in series. May be formed through the base film 50 to electrically connect the first upper wiring 11 and the first lower wiring 31 to each other. That is, the first via hole VH1 may include a conductive material filled in the first via hole VH1 to electrically connect the first upper wiring 11 and the first lower wiring 31 to each other. The flexible circuit board 100 may include a plurality of first via holes VH1. The plurality of first via holes VH1 may be arranged to overlap with the first upper via pad 10, respectively.

The flexible circuit board 100 may further include a plurality of first lower via pads 30. The plurality of first lower via pads 30 may be disposed on the other surface of the base film 50. The plurality of first lower via pads 30 may be arranged to overlap with the plurality of first via holes VH1. The plurality of first lower via pads 30 may be connected to the plurality of first lower wiring lines 31, respectively. The plurality of first lower via pads 30 may connect the plurality of first lower wiring lines 31 to the plurality of first via holes VH1. The first lower via pad 30 may have a shape in which the width of the first lower wiring 31 is extended in the first direction d1. The arrangement of the plurality of first lower via pads 30 may be substantially the same as the arrangement of the plurality of first upper via pads 10, but may not be formed in the completely same shape.

The first lower wiring 31 may be disposed on the other surface of the base film 50. The first lower wiring 31 may be a path for transmitting an electrical signal in the flexible circuit board 100. The flexible circuit board may include a plurality of first lower wiring lines 31. The plurality of first lower wiring lines 31 may be directly or indirectly connected to the plurality of first via holes VH1. The plurality of first lower wirings 31 may be electrically connected to the plurality of first upper wirings 11 through the plurality of first via holes VH1. The plurality of first lower wirings 31 may include wirings extending from the first lower via pad 30 in a direction opposite to the first upper wirings 11.

The second upper via pad 20 may be disposed on one side of the base film 50. The second upper via pad 20 may be disposed in a second region EA1 of the base film. The flexible circuit board 100 may include a plurality of second upper via pads 20. [

The second upper via pad 20 may be connected to the second upper wiring 21 and the second upper via pad 20 may be connected to the second upper via pad 20 in a shape in which the width of the second upper wiring 21 extends in the first direction d1 Lt; / RTI > The second upper via pad 20 may overlap with the second via hole VH2. That is, the second upper via pad 20 may cover the second via hole VH2.

The plurality of second upper via pads 20 may be divided into a plurality of second pad groups PG2. The plurality of second upper via pads 20 included in each of the plurality of second pad groups PG2 may be connected to the plurality of second upper wirings 21, 22 arranged continuously. Meanwhile, in the manufacturing process of the flexible circuit board 100, the first and second via holes VH1 and VH2 may be formed using a punching process. More specifically, the first and second via holes VH1 and VH2 may be formed by irradiating a laser beam onto the base film 50 to form a hole, and filling the hole with a conductive material.

The optical system used for irradiating the laser on the base film 50 may have an aberration due to its physical characteristics. In general, when the optical system located at the center of the base film 50 moves the focus and forms a via hole, the focus of the optical system in the outer region of the base film 50 is formed to deviate from the fixed position, May be formed misaligned.

In the base film 50, this outer region may include a second region EA1. Therefore, if the second upper via pad 20 formed in the second region EA1 is formed to have the same size as that of the first upper via pad 10, the second via holes VH2 are formed to be misaligned, May not overlap with the pad 20.

The area of the second upper via pad 20 may be larger than the area of the first upper via pad 10. That is, the width w3 of the second upper via pad 20 in the first direction d1 may be greater than the width w1 of the first upper via pad 10 in the first direction d1, The width w4 of the second upper via pad 20 in the third direction d3 may be greater than the width w2 of the third upper direction pad d3 in the third direction d3.

More specifically, the width w3 of the second upper via pad 20 in the first direction d1 is set to be in the range of 1.01 to 3 times the width w1 of the first upper via pad 10 in the first direction d1. Can be formed. The width w4 of the second upper via pad 20 in the third direction d3 is set to be 1.01 to 3 times larger than the width w2 of the third upper direction via d3 of the first upper via pad 10 .

When the first upper via pads 10 in the first region IA are different in size from each other, the second upper via pad 20 in the second region EA1 may have an average size of the first upper via pads 10 Lt; RTI ID = 0.0 > 1.01 < / RTI >

The widths w3 and w4 of the second upper via pad 20 may be formed to be the same as the widths w1 and w2 of the first upper via pad 10 The second via hole VH2 may be formed so as not to overlap with the second upper via pad 20.

On the other hand, when the size of the second upper via pad 20 is three times or more the size of the first upper via pad 10, the area occupied by the second upper via pad 20 in the second area EA1 is widened, The density of the wiring of the circuit board 100 can be reduced.

Therefore, when the size of the second upper via pad 20 is formed to be 1.01 times to 3 times the size of the first upper via pad 10, the margin for the misalignment of the second via holes VH2 is secured The second via hole VH2 may be formed to overlap with the second upper via pad 20.

A first pad group PG1 including a plurality of first upper via pads 10 and a second pad group PG2 including a plurality of second upper via pads 20 may be formed in different numbers of via pads . &Lt; / RTI > More specifically, the first pad group PG1 may include n first via pad 10 (n is a natural number), and the second pad group PG2 may include m (Where m is a natural number).

The areas of the first pad group PG1 and the second pad group PG2 on the base film 50 may be equal to each other and may be larger than the size of the first upper via pad 10 of the second upper via pad 20 The number of the second upper via pads 20 of the second pad group PG2 may be smaller than the number of the first upper via pads 10 of the first pad group PG1.

The flexible circuit board 100 may further include a plurality of second lower via pads 40. The plurality of second lower via pads 40 may be disposed on the other side of the base film 50. The plurality of second lower via pads 40 may be disposed on the second area EA1 of the base film 50. [ The arrangement of the plurality of second lower via pads 40 may be substantially the same as the arrangement of the plurality of second upper via pads 20, but may not be formed in the completely same shape. The plurality of second lower via pads 40 may be formed to be larger than the first lower via pad 20 in the same manner as the second upper via pad 20.

The flexible circuit board 100 may further include an insulating layer 15. The insulating layer 15 is disposed on one surface and the other surface of the base film 50 and includes first and second upper wirings 11 and 21, first and second upper via pads 10 and 20, 2 lower wirings 31, 41, and the first and second lower via pads 30, The insulating layer 15 may not be disposed on the pad for connecting the flexible circuit board 100 to components such as the display panel 200, the rigid circuit board 300, and the driving element 400.

Here, the insulating layer 15 may be formed of the first and second upper wirings 11 and 21, the first and second upper via pads 10 and 20, the first and second lower wirings 32 and 42, , And a part of the first and second lower via pads 30 and 40 may be exposed.

4 is a plan view of a flexible circuit board according to another embodiment of the present invention. Hereinafter, the description of the parts that are the same as those of the previous embodiment will be omitted and the differences will be mainly described.

Referring to FIG. 4, the base film 50 may include a first area IA, a second area EA1, and a third area EA2. The second and third regions EA1 and EA2 may be regions that sandwich the first region IA. The second area EA1 may be adjacent to one side of the first area IA and the third area EA2 may be adjacent to the opposite side of the first area. The second region EA1 may include one end 110 of the base film 50 and the third region EA2 may include the other end 111 of the base film 50. [

The flexible circuit board 100 may include a third pad group PG3 in which a plurality of first upper via pads 10 are arranged in a fourth direction d4 which is oblique to the third direction.

The flexible circuit board 100 may further include a plurality of fourth upper via pads 23. The fourth upper via pad 23 may be disposed on one side of the base film 50. The fourth upper via pad 23 may be disposed in the third region EA2 of the base film.

The fourth upper via pad 23 may be connected to the third upper wiring 24 and the fourth upper via pad 23 may be connected to the third upper wiring pad 24 in a shape in which the width of the third upper wiring 24 extends in the first direction d1 Lt; / RTI > The fourth upper via pad 23 may overlap the fourth via hole VH4.

The fourth upper via pad 23 may be of a different size than the first and second upper via pads 10, 20. Specifically, the area of the fourth upper via pad 23 may be larger than the area of the first and second upper via pads 10, 20. The width w5 of the fourth upper via pad 23 in the first direction d1 may be greater than the width w3 of the second upper via pad 20 in the first direction d1, The width w6 of the upper via pad 23 in the third direction d3 may be larger than the width w4 of the second upper via pad 20 in the third direction d3.

The flexible circuit board 100 may include a plurality of fourth lower via pads (not shown) disposed on the other surface of the base film 50 so as to correspond to the fourth upper via pad 23.

The first pad group PG1 may include a first via hole group VHG1 disposed on a straight line L1 extending in the first direction d1. And the second pad group PG2 may include a second via hole group VHG2 disposed on the straight line L1. The first via hole group VHG1 and the second via hole group VHG2 may be disposed on the same straight line L1 extending in the first direction d1.

The first via hole group VHG1 group disposed in the first region and the second via hole group VHG2 disposed in the second region are disposed on the same straight line L1, And the second via-hole group (VHG2) can be reduced. That is, when the first via hole group VHG1 and the second via hole group VHG2 are not located on the same straight line, for example, the base film 50 is laser-processed to form the first via hole group VHG1 After the formation, the laser irradiation position in the third direction d3 is manipulated, and then the generation of the second via-hole group VHG2 can be resumed. In some embodiments of the present invention, the first via-hole group VHG1 and the second via-hole group VHG2 are located on the same straight line L1 and are formed without the operation of the third direction d3 of the laser irradiation position .

The third via hole group VHG3 disposed in the first region and the fourth via hole group VHG4 disposed in the third region may be disposed on the same straight line L2.

The first and second upper via pads 10 and 20 and the first and second lower via pads 30 and 40, the fourth upper via pad 23, And can be connected to the upper wiring and the lower wiring.

Meanwhile, as another embodiment of the present invention, the total width of the flexible circuit board 100 may be 10 mm to 250 mm, and particularly 35 mm, 70 mm, 96 mm, and 105 mm.

Here, when the total width of the flexible circuit board 100 is 70 mm, the first area IA may be 50 mm to 60 mm.

Although not shown in the drawing, a region where a sprocket hole is formed along the longitudinal direction d3 of the base film 50 with a predetermined width is formed at the edge of the base film 50 included in the second area EA1 or the third area EA2 And the region where the sprocket holes are formed can be cut and removed later.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

100: flexible circuit board 50: base film
200: display panel 300: rigid circuit board
PG1 to PG4: Pad group

Claims

A base film;
A plurality of via holes passing through the base film;
An upper wiring formed on one surface of the base film and a lower wiring formed on the other surface of the base film; And
And a plurality of via pads formed on the one surface and the other surface of the base film so as to overlap the plurality of via holes and electrically connect the upper wiring and the lower wiring,
Wherein the base film includes a first region including an inner side in a width direction or a longitudinal direction of the base film and a second region including an outer side in a width direction or a longitudinal direction of the base film,
Wherein the plurality of via-
A plurality of first via pads disposed in the first region and having a predetermined area to cover the via hole,
And a plurality of second via pads disposed in the second region and having an area larger than an area of the first via pad.

The method according to claim 1,
Wherein the width dimension or the width dimension of the second via pad is 1.01 to 3 times the width dimension or the width dimension of the first via pad, respectively.

The method according to claim 1,
Wherein an average size of a width dimension or a length dimension of the second via pad is 1.01 to 3 times an average size dimension or width dimension of the width of the first via pad, respectively.

The method according to claim 1,
Wherein the base film has a width of 70 mm and the width of the first region is 50 mm to 60 mm.

The method according to claim 1,
Wherein the base film further comprises a sprocket hole formed along an edge of the base film along the longitudinal direction.

The method according to claim 1,
Wherein the plurality of first via pads form a plurality of first pad groups aligned in a diagonal diagonal direction with respect to the longitudinal direction and adjacent to each other,
Wherein the plurality of second via pads form a plurality of second pad groups aligned in the diagonal direction and adjacent to each other.

The method according to claim 6,
The first pad group includes n first via pads (n is a natural number)
Wherein the second group comprises m second via pads of less than n (where m is a natural number).

The method according to claim 6,
Wherein the plurality of first pad groups includes a first via hole group, the first via hole group includes the plurality of via holes arranged on a straight line extending in the width direction,
The plurality of second pad groups includes a second via hole group, and the second via hole group includes the plurality of via holes arranged on a straight line extending in the width direction,
And the first via-hole group and the second via-hole group are arranged on the same line.