JP2008071889A - Wiring circuit board connection structure, and electronic device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable formation of connection lands with a higher integration density and also enable easy connection between wiring circuit boards. <P>SOLUTION: First connection lands 11a, 12a and second connection lands 11b, 12b larger in width than the first connection lands are alternately formed on a first wiring circuit board 11 and a second wiring circuit board 12 with equal intervals so that the first connection lands are extruded more than the second connection lands respectively. A projection 11ap of the first connection land 11a in the first wiring circuit board is mounted on the second connection land 12b of the second wiring circuit board. A projection 12ap of the first connection land 12a in the second wiring circuit board is mounted on the second connection land 11b of the first wiring circuit board. Thereafter, the projection 11ap (12ap) of the first connection land is connected to the second connection land 12b (11b). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wiring board connection structure and an electronic device using the same. Specifically, the first connection land and the second connection land having a wider land width than the first connection land are alternately arranged at equal intervals so that the first connection land protrudes from the second connection land. By forming the first connecting land and connecting the protruding portion of the first connecting land and the second connecting land, the connecting land can be increased in density and the board connecting operation can be facilitated.

  Conventionally, in an electronic device, a connection land is formed on a first wiring board and a second wiring board, and the second wiring board is placed so that the connection land overlaps the first wiring board. A connection land formed on the first wiring board and a connection land formed on the second wiring board are connected.

  When two wiring boards are connected in this way, in the inventions of Patent Documents 1 and 2, the width of the connection land formed on the circuit board is made wider than the width of the connection land formed on the flexible board. Suppression and miniaturization are attempted.

JP-A-8-23147 Japanese Patent Publication No.55-10998

  By the way, if the connection land of the other wiring board is made wider than the connection land of one wiring board, for example, when the connection land is soldered, the fillet spreads from the narrow connection land toward the wide connection land. Therefore, the generation of solder bridges can be prevented. However, since the connection land of the other wiring board is formed wide, the density of the connection land is hindered.

  In addition, if the density of the connection lands is increased, the positioning when connecting the wiring boards needs to be performed with high accuracy. For this reason, image recognition is performed by picking up a board with a camera, and a desired positioning accuracy is ensured by adjusting the position of the wiring board based on the recognition result. Therefore, it becomes impossible to easily connect the wiring boards with an inexpensive configuration.

  Therefore, the present invention provides a wiring board connection structure that can increase the density of connection lands and can easily connect substrates, and an electronic apparatus using the wiring board connection structure.

  In the wiring board connection structure according to the present invention, a second wiring board is placed on the first wiring board, and a connection land formed on the first wiring board and a connection land formed on the second wiring board. In each of the first and second wiring boards, the first connection land and the second connection land wider than the first connection land are provided on each of the first and second wiring boards. The first and second wiring boards are alternately formed at equal intervals so as to protrude from the two connecting lands, and the first and second wiring boards are on the second connecting lands of one of the wiring boards. The protruding portion is placed to connect the first connection land and the second connection land.

  According to this invention, the first connection land and the second connection land having a wider land width than the first connection land are alternately arranged at equal intervals so that the first connection land protrudes from the second connection land. The first and second wiring boards are formed so that the protruding portion of the first connection land in the other wiring board is placed on the second connection land of the one wiring board. Two connected lands are connected.

  For this reason, the connection points between the first connection lands and the second connection lands are arranged in a staggered manner, and the density of the connection lands can be increased. Further, since the first connection land is mounted and connected on the second connection land having a wide land width, the connection width of the connection point does not vary even if the substrate is not positioned with high accuracy. Therefore, a stable connection structure can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The wiring board connection structure according to the present invention is suitable for use in various electronic devices such as video equipment, audio equipment, communication equipment, and information equipment. As the wiring substrate, not only a rigid substrate but also a flexible substrate having flexibility may be used. Furthermore, when wiring boards are connected to each other, a flexible board is often used, and the wiring board connection structure according to the present invention is suitable for connection to a wiring board using such a flexible board. .

  FIG. 1 shows a connection land shape of a wiring board used in the wiring board connection structure of the present invention. On the wiring board 11 (12), first connection lands 11a (12a) and second connection lands 11b (12b) having a land width wider than the first connection lands 11a (12a) are alternately formed. A space is provided between adjacent connection lands. The first connection land 11a (12a) is formed so as to protrude from the second connection land 11b (12b) (hereinafter, the protruding portion is referred to as a protruding portion 11ap (12ap)).

  2 shows a wiring board connection structure according to the present invention. FIG. 2A is a front view of the wiring board connection structure, FIG. 2B is a side view of the wiring board connection structure, and FIG. 2C is a view taken along the line II ′ in FIG. FIG. 2D is a schematic cross-sectional view taken along the line II-II ′ in FIG. 2A.

  The first wiring board 11 and the second wiring board 12 have the protruding portion of the first connecting land on the second connecting land of the other wiring board placed on the second connecting land of the other wiring board. And the second connection land are connected. That is, the protruding portion 12ap of the first connection land 12a in the second wiring board 12 is placed on the second connection land 11b of the first wiring board 11. Further, the protruding portion 11ap of the first connection land 11a in the first wiring board 11 is placed on the second connection land 12b of the second wiring board 12. Then, the protrusion 11ap of the first connection land 11a and the second connection land 12b, and the protrusion 12ap of the first connection land 12a and the second connection land 11b are connected. At this time, the connection points where the first connection lands and the second connection lands are connected are staggered. Note that one wiring board is placed on the other wiring board so that the second connection land 11b of the first wiring board 11 and the second connection land 12b of the second wiring board 12 have a space larger than the land gap. The mounting can provide a predetermined gap or more between the lands in the connected wiring board.

  Here, when the minimum land width of the connection land is “Pw” and the land gap that is a space between the adjacent connection lands is “Pd”, the connection work can be easily performed at low cost. The case where the allowable shift amount in the connection work is set to “As” will be described. Here, the deviation allowable amount indicates an allowable deviation amount in the connecting land arrangement direction with respect to the reference connection position, and the deviation amount in one direction with respect to the reference connection position is defined as an allowable deviation amount. This means that only “As” is allowed, and the deviation amount in the reverse direction is allowed by the deviation tolerance amount “As”.

  As shown in FIG. 3, when the land width of the first connection lands 11a and 12a on the wiring boards 11 and 12 is “Pw”, the land width of the second connection lands 11b and 12b is “Pw + 2As”. When the land gap is “Pd”, the distance between the first connection land 11a (12a) and the adjacent first connection land 11a (12a) is “Pw + 2As + 2Pd”, which is adjacent to the second connection land 11b (12b). The distance from the second connection land 11b (12b) is “Pw + 2Pd”.

  Accordingly, the first connection lands 11a and 12a in the wiring boards 11 and 12 are formed so that the L / S value for the first connection lands 11a and 12a is L / S = Pw / (Pw + 2As + 2Pd). The second connection lands 11b and 12b are formed so that the L / S value for the second connection lands 11b and 12b is L / S = (Pw + 2As) / (Pw + 2Pd). L / S means Line / Space, where a line represents a pattern width and a space represents a gap between patterns.

  Further, in the wiring board 11, the first connection land 11a is provided at the center position between the second connection lands 11b so that the first connection land 11a and the second connection land 11b are equally spaced. Similarly, in the wiring board 12, the first connection land 12a is provided at the center position between the second connection lands 12b so that the first connection land 12a and the second connection land 12b are equally spaced.

  Thus, when the first connection lands 11a, 12a and the second connection lands 11b, 12b are formed, the connection pitch CPa is “CPa = (Pw + As + Pd)”, and the connection points are staggered.

  Next, a case where the connection pitch is set in order to increase the density of the connection lands when the minimum land width of the connection lands is “Pw” and the land gap is “Pd” will be described. Here, since the connection pitch is “CPa = (Pw + As + Pd)”, “As = (CPa−Pw−Pd)”. Accordingly, the L / S value for the first connection lands 11a and 12a is L / S = Pw / (Pw + 2As + 2Pd) = Pw / (2CPa−Pw). The L / S values of the second connection lands 11b and 12b are L / S = (Pw + 2As) / (Pw + 2Pd) = (2CPa−Pw−2Pd) / (Pw + 2Pd). That is, the first connection lands 11a and 12a have an L / S value of L / S = Pw / (2CPa−Pw), and the second connection lands 11b and 12b have an L / S value of L / S = (2CPa−Pw). -2Pd) / (Pw + 2Pd), it is possible to connect the wiring boards at a desired connection pitch with the staggered connection points.

  Next, differences from the conventional wiring board will be described. For example, in a wiring board configured as in the invention of Patent Document 1, assuming that the minimum land width of the connection land is “Pw” and the allowable displacement with respect to the reference position is “As”, as shown in FIG. When the connection land 13p of the wiring board 13 is a land width “Pw”, the land width Wd of the connection land 14p in the fourth wiring board 14 is “Pw + 2As”. If the land gap is “Pd”, the land gap for the connection land 13p is “Pw + 2As”, and the land gap for the connection land 14p is “Pd”. Therefore, the connection land 13p is formed to satisfy L / S = Pw / (Pw + 2As + Pd), and the connection land 14p is formed to satisfy L / S = (Pw + 2As) / Pd. The connection pitch CPc is “CPc = (Pw + 2As + Pd)”.

  Here, for example, when the connection pitches CPa and CPc are both 0.3 mm, the minimum land width Pw is 0.1 mm, and the land gap Pd is 0.1 mm, when the connection lands are formed as shown in FIG. The capacity As is 0.05 mm. However, as shown in FIG. 3, when the connection land is formed, the allowable deviation As is 0.1 mm, and the allowable deviation can be increased. Further, when the displacement tolerance As is set to 0.1 mm using the conventional wiring board connection structure, the connection pitch CPc is 0.4 mm, which is the connection pitch CPa when the connection land is formed as shown in FIG. It becomes larger than 0.3 mm.

  In this way, when the connection pitch is the same, the displacement tolerance can be increased as compared with the conventional wiring board connection structure. Therefore, a highly accurate and expensive connection method, for example, a connection method in which the substrate is aligned by image recognition using a camera and the substrate is connected using an anisotropic conductive film (ACF). Even if alignment is performed using the board shape, for example, by restricting the wiring boards of each other with the outer shape and performing soldering, a stable connection structure can be obtained without causing variations in the connection width of the connection points. It is done. Further, when the allowable displacement amount is set equal, the connection pitch can be narrower than that of the conventional wiring board connection structure, so that the density of the connection lands can be increased without increasing the board connection accuracy. The alignment using the board shape is not limited to the case where the wiring board is regulated by the outer shape, and for example, positioning holes provided in the wiring board may be used.

  The wiring board has a wiring rule of 0.2 mm pitch (L / S = 0.1 mm / 0.1 mm), and pattern design is performed. As shown in FIG. 1, first connection lands and second connection lands are alternately provided and staggered. Arranged. Here, the land width of the first connection land is “Pa = 0.1 mm”, and the land width of the second connection land is “Pb = 0.3 mm”. The land gap between adjacent connection lands was “Pd = 0.1 mm”, and the connection points were arranged in a staggered manner with a pitch of 0.3 mm. In this case, the allowable deviation is “As = 100 μm”. The processing accuracy of the connection portion of the wiring board was set to be the same processing accuracy as when a 0.3 mm pitch staggered connector was used. Further, SnCu plating is applied to one of the first or second connection lands.

  The two wiring boards formed in this way were overlapped by, for example, the outer shape regulation using the board shape. In the superposition of the two wiring boards, the second connection land of the other wiring board is placed on the first connection land of one wiring board, and the first connection land and the second connection land are connected by thermocompression bonding. did.

  As a result of measuring the shift amount of the connection portion after thermocompression bonding, the standard deviation of the shift amount was “σ = 11.67 μm”. When the control limit is set to “± 3σ”, the control limit “± 3σ” is “± 35 μm”, and therefore, even if a shift occurs in any direction, the allowable shift amount is “As = 100 μm”. Accordingly, even if the substrate is not aligned by image recognition using a camera and the substrate is not connected, the substrate can be connected within the allowable deviation range by the substrate alignment using the substrate shape.

It is a figure which shows the connection land shape of a wiring board. It is a figure which shows a wiring board connection structure. It is a figure which shows the connection land setting method. It is a figure which shows the conventional connection land setting method.

Explanation of symbols

  11, 12, 13, 14 ... wiring board, 11a, 12a ... first connection land, 11b, 12b ... second connection land, 11ap, 12ap ... projection, 13p, 14p ... Connection land

Claims (5)

In a wiring board connection structure in which a second wiring board is mounted on a first wiring board and a connection land formed on the first wiring board is connected to a connection land formed on the second wiring board. ,
Each of the first and second wiring boards includes a first connection land and a second connection land having a land width wider than the first connection land, and the first connection land protrudes from the second connection land. Alternately formed at regular intervals so that
The first and second wiring boards are configured such that a protruding portion of the first connection land in the other wiring board is placed on the second connection land of one wiring board, and the first connection land and the second wiring board A wiring board connection structure, wherein the second connection land is connected. When the minimum land width is “Pw”, the land gap is “Pd”, and the allowable deviation is “As”,
The L / S value for the first connection land is set to “L / S = Pw / (Pw + 2As + 2Pd)”, and the L / S value for the second connection land is “L / S = (Pw + 2As) / (Pw + 2Pd). 2. The wiring board connection structure according to claim 1, wherein the wiring board connection structure is set to “)”. When the minimum land width is “Pw”, the land gap is “Pd”, and the connection pitch is “CPa”,
The L / S value for the first connection land is set to “L / S = Pw / (2CPa−Pw)”, and the L / S value for the second connection land is “L / S = (2CPa−Pw). The wiring board connection structure according to claim 1, wherein “−2Pd) / (Pw + 2Pd)” is set. The first wiring board and the second wiring board are positioned using a board shape, and the first connection land of the other wiring board protrudes on the second connection land of one wiring board. 2. The wiring board connection structure according to claim 1, wherein the portion is placed. In an electronic device using a first wiring board and a second wiring board on which a circuit pattern is formed,
Each of the first and second wiring boards includes a first connection land connected to the circuit pattern and a second connection land having a land width wider than the first connection land, and the first connection land includes the second connection land. Form alternately so that it protrudes from the connection land,
The first and second wiring boards are configured such that a protruding portion of the first connection land in the other wiring board is placed on the second connection land of one wiring board, and the first connection land and the second wiring board An electronic device characterized in that a second connection land is connected.

Images