The present invention relates to a printed circuit board connection structure.
In recent years, a structure to connect printed circuit boards has often been used in electronic devices (for example, see Patent Literature 1). The method illustrated in
In the method for connection illustrated in
In
Subsequently, as illustrated in
PTL 1: JP2012-28745A
In the above-described method for connection, the rigid printed circuit board 110 and the flexible printed circuit board 130 are aligned with a predetermined gap therebetween as illustrated in
As a result, during alignment, even if the recognition marks 134 and 135 on the flexible printed circuit board 130 side are aligned to overlap perfectly with the corresponding recognition marks 114 and 115 on the rigid printed circuit board 110 side, as illustrated in
One foreseeable way of addressing this problem is to align the marks so that the recognition marks 134 and 135 are offset with respect to the corresponding recognition marks 114 and 115 by the distance of misalignment after clamping. This approach, however, makes alignment troublesome and time-consuming and also lowers the yield. Note that this problem also occurs in a structure to connect flexible printed circuit boards to each other.
A printed circuit board connection structure according to the present invention is formed by clamping and connecting a first printed circuit board and a second printed circuit board, at least one of which is a flexible printed circuit board, with a conductive adhesion layer therebetween, the printed circuit board connection structure comprising: a first mark formed on the first printed circuit board; and a second mark formed on the second printed circuit board, wherein an area enclosed by a perimeter of one mark out of the first mark and the second mark is greater than an area enclosed by a perimeter of the other mark, and with the printed circuit board and the second printed circuit board in an allowable state of connection, at least a portion of a region enclosed by the perimeter of the other mark is located within a region enclosed by the perimeter of the one mark when viewed in a direction of stacking of the printed circuit board and the second printed circuit board.
The first printed circuit board is preferably a rigid printed circuit board, the second printed circuit board is preferably a flexible printed circuit board, and the area enclosed by the perimeter of the first mark is preferably greater than the area enclosed by the perimeter of the second mark.
With the first printed circuit board and the second printed circuit board in the allowable state of connection, a portion of the first mark preferably protrudes outward from the second printed circuit board when viewed in the direction of stacking.
The present invention will be further described below with reference to the accompanying drawings, within:
a) is a plan view illustrating the structure of the main parts of a printed circuit board connection structure according to Embodiment 1;
b) is a partial enlargement of the structure of the printed circuit board connection in
a) illustrates alignment of the printed circuit boards in
b) is a partial enlargement of the alignment of the printed circuit boards in
a) illustrates the connection terminal rows and recognition marks formed on the printed circuit boards in
b) illustrates the back view of the connection terminal rows and recognition marks formed on the printed circuit boards in
a) illustrates alignment of the printed circuit boards in
b) is a partial enlargement of the alignment of the printed circuit boards in
a) illustrates a conventional printed circuit board connection structure;
b) is a partial enlargement of the alignment of the printed circuit boards in
The following describes embodiments of the present invention with reference to the drawings.
a) is a plan view illustrating the structure of the main parts of a printed circuit board connection structure according to Embodiment 1 of the present invention. The connection structure according to the present embodiment includes a rigid printed circuit board 10 and a flexible printed circuit board 20. Recognition marks 14 and 15 for alignment, which constitute the first mark, are respectively formed integrally with connection terminals 12 and 13 at either edge of a connection terminal row 11 on the pattern side in the rigid printed circuit board 10. The recognition marks 14 and 15 protrude outward from the connection terminal row 11. As in the rigid printed circuit board 10, recognition marks 24 and 25 for alignment, which constitute the second mark, are respectively formed integrally with connection terminals 22 and 23 at either edge of a connection terminal row 21 on the pattern side in the flexible printed circuit board 20. The recognition marks 24 and 25 protrude outward from the connection terminal row 21.
In the present embodiment, the recognition marks 14 and 15 protrude in a direction perpendicular to the direction of elongation of the corresponding connection terminals 12 and 13 and have a solid rectangular shape. Similarly, the recognition marks 24 and 25 protrude in a direction perpendicular to the direction of elongation of the corresponding connection terminals 22 and 23 and have a solid rectangular shape.
The recognition marks 14 and 15 are formed to have a larger area than the recognition marks 24 and 25, so that the recognition marks 24 and 25 are positioned within the region of the corresponding recognition marks 14 and 15 when viewed in the direction of stacking of the rigid printed circuit board 10 and the flexible printed circuit board 20 with the rigid printed circuit board 10 and the flexible printed circuit board 20 in a state of being connected within an acceptable range of the design value. In other words, as illustrated by the partial enlargement in
In this way, it is easy to recognize that the rigid printed circuit board 10 and the flexible printed circuit board 20 are connected within an acceptable range of the design value if the recognition marks 24 and 25 are located within the region of the corresponding recognition marks 14 and 15. Note that the recognition marks 24 and 25 may be formed to be shifted towards the tip of the connection terminals 22 and 23 by the below-described amount of misalignment ΔL when clamping the flexible printed circuit board 20.
Next, a method for connecting the rigid printed circuit board 10 and the flexible printed circuit board 20 to obtain the connection structure according to the present embodiment is described.
As illustrated in
Next, an image of the overlapping region between the connection terminal row 11 of the rigid printed circuit board 10 and the connection terminal row 21 of the flexible printed circuit board 20 is captured with a camera 160 for recognition, and while the image is observed, the flexible printed circuit board 130 is turned in a plane and moved in two dimensions, with the adjustment stage 140. In this way, as illustrated in
Subsequently, as illustrated in
As described above, according to the connection structure of the present embodiment, by matching the edges of the recognition marks 24 and 25 closer to the tip of the connection terminals 22 and 23 in the flexible printed circuit board 20 to the edges of the corresponding recognition marks 14 and 15 further away from the tip of the connection terminals 12 and 13 in the rigid printed circuit board 10, the flexible printed circuit board 20 can be aligned with the rigid printed circuit board 10. Alignment thus becomes easy. Furthermore, the recognition marks 24 and 25 and the recognition marks 14 and 15 are formed taking into consideration the misalignment ΔL when clamping and connecting the flexible printed circuit board 20, and in a state with the recognition marks 24 and 25 located within the region of the corresponding recognition marks 14 and 15, the rigid printed circuit board 10 and the flexible printed circuit board 20 are connected with an acceptable range of the design value. Accordingly, the rigid printed circuit board 10 and the flexible printed circuit board 20 can be connected easily and accurately, the yield can be increased, and the state of connection can easily be recognized.
According to the connection structure of the present embodiment, similar effects to those of Embodiment 1 are obtained. Additionally, even when the optical transparency of the flexible printed circuit board 20 is low, making it difficult to see the rigid printed circuit board 10 below, alignment is made easier since the large recognition marks 14 and 15 of the rigid printed circuit board 10 protrude outward from the flexible printed circuit board 20.
The present invention is not limited to the above embodiments, and a variety of modifications and changes are possible. For example, in the above embodiments, the recognition marks 24 and 25 of the flexible printed circuit board 20 may be formed to be larger than the recognition marks 14 and 15 of the rigid printed circuit board 10. In this case, the recognition marks 24 and 25 may be aligned with the recognition marks 14 and 15 before clamping and connecting by matching the edges of the recognition marks 24 and 25 further away from the tip of the connection terminals 22 and 23 to the edges of the corresponding recognition marks 14 and 15 closer to the tip of the connection terminals 12 and 13.
In the above embodiments, the recognition marks on each printed circuit board are not limited to a solid rectangular shape that protrudes in a direction perpendicular to the direction of elongation of the corresponding connection terminal and may be formed as any solid or hollow shape that protrudes in any direction from the connection terminal row. Therefore, the recognition marks may, for example, be solid or hollow shape with a curved perimeter. The recognition marks in each printed circuit board are not limited to the case of the entire region enclosed by the perimeter of the other mark being located within the region enclosed by the perimeter of the one mark when viewed in the direction of stacking with the printed circuit boards in an allowable state of connection. Rather, a portion of the region enclosed by the perimeter of the other mark may be located within a predetermined portion of the region enclosed by the perimeter of the one mark.
Furthermore, the present invention is not limited to a connection structure for a rigid printed circuit board and a flexible printed circuit board and may be similarly applied to a connection structure for flexible printed circuit boards. The recognition marks in the printed circuit boards are not limited to being formed integrally with the connection terminals but rather may be formed separately and independently from the connection terminals. Moreover, the recognition marks and the printed circuit boards are not limited to the case of one recognition mark being formed on each side of the connection terminal row. A plurality of recognition marks may be formed, or one or more recognition marks may be formed on only one side of the connection terminal row. The conductive adhesion layer connecting the printed circuit boards is not limited to conductive adhesive and may be formed with a conductive adhesion film such as anisotropic conductive film (ACF) or with a different conductive adhesion material.
10: Rigid printed circuit board
11: Connection terminal row
12, 13: Connection terminal
14, 15: Recognition mark
20: Flexible printed circuit board
21: Connection terminal row
22, 23: Connection terminal
24, 25: Recognition mark
120: Substrate stage
140: Adjustment stage
150: Conductive adhesive
160: Camera for recognition
170: Clamping head
Number | Date | Country | Kind |
---|---|---|---|
2012-147329 | Jun 2012 | JP | national |
The Present application is a Continuing Application based on International Application PCT/JP2013/003958 filed on Jun. 25, 2013, which, in turn, claims the priority from Japanese Patent Application No. 2012-147329 filed on Jun. 29, 2012, the entire disclosure of these earlier applications being herein incorporated by reference.
Number | Date | Country | |
---|---|---|---|
Parent | PCT/JP2013/003958 | Jun 2013 | US |
Child | 14453941 | US |