JP2007201263A - Mounting structure of flexible substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting structure of a flexible substrate without disconnection of a lead-out conductor. <P>SOLUTION: In the mounting structure of the flexible substrate, a flexural guide 14 and a reinforcing material 15 between the flexural guide 14 and the one end 5a of the circuit board 5 are formed in a flexible substrate 10. When the flexible substrate 10 is bent, it follows on the deflection of the flexural guide 14, the reinforcing material 15 serves as a warpage margin, and it is bent gently, a bending stress distributes, a stress concentration of the flexible substrate 10 does not occur in the end 5a of the circuit board 5. Accordingly, a material can be obtained without disconnection in the lead-out conductor 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a flexible substrate mounting structure suitable for use in camera modules and various electronic circuit units used in mobile phones and the like.

  FIG. 6 is a cross-sectional view of the main part of the conventional flexible substrate mounting structure. Next, the configuration of the conventional flexible substrate mounting structure will be described with reference to FIG. In addition, an anisotropic conductive film 53 is connected to a terminal group provided on the upper surface of the glass substrate 51.

  The strip-shaped flexible substrate 54 includes a lead conductor 55 provided on the bottom surface side, a first insulating film 56 provided on the bottom surface excluding the terminal portion 55a at the end of the lead conductor 55, a terminal portion 55a, and a first portion. A second insulating film 57 provided on the upper surface is provided in a state facing a part of the insulating film 56.

  And this flexible substrate 54 is attached to the glass substrate 51 by crimping the terminal portion 55a to the anisotropic conductive film 53 on the glass substrate 51, and a conventional flexible substrate mounting structure is configured (for example, Patent Document 1).

  In such a conventional flexible substrate mounting structure, the vicinity of one end (side surface) 51a of the glass substrate 51 is a bending inducing portion 58 having a low bending strength, and is opposite to the one end 51a with respect to the inducing portion 58. In this state, the reinforcing portion 59 having a bending strength stronger than that of the inducing portion 58 is present.

That is, the second insulating film 57 is present at the position of the inducing portion 58, and the first and second insulating films 56, 57 are present at the position of the reinforcing portion 59. When bent in the A direction, the inducing portion 58 easily bends with the one end (side surface) 51a side of the glass substrate 51 as a fulcrum, so that the inducing portion 58 bends in a state where stress is concentrated and is located in a stress concentration state. A situation occurs in which the lead conductor 55 hits one end 51a of the glass substrate 51 and is disconnected.
JP 2003-133777 A

  However, in the conventional flexible substrate mounting structure, in the flexible substrate 54, the inducing portion 58 where the second insulating film 57 exists is located near the one end 51a of the glass substrate 51, and the first and second insulating films 56 are provided. , 57 is located at a position away from the one end 51a of the glass substrate 51. Therefore, when the flexible substrate 54 is bent in the direction of arrow A, the inducing portion 58 is easily bent and is in a stress concentration state. There is a problem that a situation occurs in which the lead conductor 55 hits one end 51a of the glass substrate 51 and is disconnected.

  The present invention has been made in view of such a state of the art, and an object of the present invention is to provide a flexible substrate mounting structure in which a lead conductor is not disconnected.

  In order to achieve the above object, the present invention provides a circuit board provided with a land part, a strip-like flexible board having a lead conductor connected to the land part, and a state in which the flexible board is superimposed on the circuit board. In the case where the flexible board protrudes from one end of the circuit board and is attached to the circuit board, the flexible board is provided at a position near one end away from one end of the circuit board, and the bending inducing portion having a lower bending strength than the surroundings. The bending portion is stronger than the inducing portion, and has a reinforcing portion provided adjacent to the inducing portion, and the reinforcing portion is disposed between the inducing portion and one end.

  In the present invention configured as described above, when the flexible substrate is bent, the bending portion is bent at the position of the bending induction portion, and the reinforcement portion positioned between the induction portion and one end of the circuit board is accompanied by the bending of the induction portion. The bending stress is gently bent as the bending allowance, the bending stress is dispersed, the stress concentration of the flexible substrate does not occur at one end of the circuit substrate, and therefore, the lead conductor without disconnection can be obtained.

  Moreover, the present invention is characterized in that, in the above-mentioned invention, the inducing portion is provided in a direction orthogonal to the protruding direction of the flexible substrate.

  According to the present invention configured as described above, a flexible substrate and a lead conductor with stable bending can be obtained.

  Further, the present invention is characterized in that, in the above-mentioned invention, the flexible substrate is provided with an insulating film covering the lead conductor, and the inducing portion is formed by the insulating film removing portion.

  In the present invention configured as described above, it is only necessary to remove the insulating film, and the structure is simple and inexpensive.

  Further, the present invention is characterized in that, in the above-mentioned invention, the insulating film removal portion is provided over the entire width in a direction orthogonal to the protruding direction of the flexible substrate.

  In the present invention configured as described above, since the removing portion is provided in the entire width of the flexible substrate, the flexible substrate can be easily bent in the induction portion.

  Further, the present invention is characterized in that, in the above invention, the inducing portion is formed by a removing portion provided in the insulating film in a state where the insulating film on the lead conductor is left.

  According to the present invention configured as described above, it is not necessary to protect the lead conductor exposed by the induction portion by solder plating, and a product with good productivity and low cost can be obtained.

  Moreover, the present invention is characterized in that in the above invention, the insulating film is interposed between the circuit board and the flexible substrate.

  According to the present invention configured as described above, the lead conductor does not directly hit one end of the circuit board due to the intervening insulating film, and the lead conductor is not cut.

  Moreover, the present invention is characterized in that, in the above invention, the flexible substrate is provided with a plurality of holes, and the inducing portion is formed by the holes.

  According to the present invention configured as described above, it is possible to easily form the inducing portion and to easily bend the flexible substrate in the inducing portion.

  In addition, the present invention is characterized in that, in the above invention, an image sensor for a camera module is connected to the circuit board, and a signal from the image sensor is derived through the flexible substrate.

  Even when the present invention configured as described above is applied to a camera module in which a flexible substrate is repeatedly bent, the lead conductor can be obtained without being cut.

  According to the present invention, when the flexible substrate is bent, it bends at the position of the bending induction portion, and along with the bending of the induction portion, the reinforcing portion located between the induction portion and one end of the circuit board becomes a bending allowance. By bending gently, the bending stress is dispersed, and the stress concentration of the flexible board does not occur at one end of the circuit board, and therefore, the lead conductor without disconnection can be obtained.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, an embodiment of the present invention will be described. FIG. 1 is a cross-sectional view of a main part according to a first embodiment of the flexible substrate mounting structure of the present invention, and FIG. FIG. 3 is a plan view of a flexible substrate according to one embodiment, FIG. 3 is an explanatory diagram showing a bent state of the flexible substrate according to the first embodiment of the flexible substrate mounting structure of the present invention, and FIG. 4 is a flexible substrate according to the present invention. FIG. 5 is a plan view of a flexible substrate according to a second embodiment of the flexible substrate mounting structure of the present invention.

  Next, the structure according to the first embodiment of the flexible substrate mounting structure of the present invention will be described with reference to FIGS. 1 to 3 by taking a case where it is applied to a camera module as an example. A lens 2 is attached to the attachment member 1, and an infrared removing filter (IR cut filter) 4 is attached to the cylindrical holding member 3, and the attachment member 1 and the holding member 3 are coupled.

  A plurality of land portions 6 made of a conductive material are provided on the upper and lower surfaces of the circuit board 5 made of an insulating material, and these land portions 6 located on the upper and lower surfaces are connected by connecting conductors 7. Yes.

  The image pickup device 8 has a plurality of electrodes 9, and the image pickup device 8 is connected to a land portion 6 positioned on the upper surface by a conductor such as solder while being placed on the circuit board 5. Yes.

  The circuit board 5 to which the image pickup device 8 is attached is attached to the holding member 3 so as to close the lower portion of the holding member 3 in a state where the image pickup device 8 is positioned in the holding member 3. 2 is in a state in which the infrared filter 4 is disposed.

  The strip-shaped flexible substrate 10 includes a lead conductor 11 in which a plurality of strips are arranged in parallel in the longitudinal direction, and an insulating film 12 made of a resin such as a resist provided so as to cover the lead conductor 11.

  The insulating film 12 exposes the terminal portion 11a provided at the end portion of the lead conductor 11, and the insulating film 12 is provided across the entire width of the flexible substrate 10 in a direction orthogonal to the longitudinal direction. A removal unit 13 is provided.

  And by providing this removal part 13, this removal part 13 turns into the bending induction part 14 whose bending strength is weaker than the circumference | surroundings, and the part with the insulating film 12 adjacent to this induction part 14 (removal part 13) is The reinforcing portion 15 has a bending strength stronger than that of the inducing portion 14.

  In the flexible substrate 10 having such a configuration, the insulating film 12 side is overlapped with the lower surface of the circuit substrate 5, and the terminal portion 11 a is connected to the land portion 6 positioned on the lower surface of the circuit substrate 5 by a conductor such as solder. A substrate 10 is attached to the circuit board 5.

  When the flexible substrate 10 is attached, the flexible substrate 10 protrudes from one end 5 a of the circuit substrate 5, and the inducing portion 14, which is a removal portion 13 provided on the insulating film 12, extends from the one end 5 a of the circuit substrate 5. The reinforcing part 15 having the insulating film 12 exists between the induction part 14 and the one end 5a of the circuit board 5 while being located in the vicinity of the remote end 5a.

  In addition, solder plating that covers the lead conductor 11 is provided at the location of the lead conductor 11 exposed by the removal portion 13 to prevent oxidation of the lead conductor 11 and the like, and the flexible substrate mounting structure of the present invention is formed. ing.

  For example, the camera module to which the flexible substrate mounting structure of the present invention is applied is incorporated in a mobile phone, a camera, or the like, the flexible substrate 10 is routed to a predetermined location, and the lead conductor 11 is focused. It is connected to an electric circuit such as a circuit, and a signal from the image sensor 8 is led out through the lead conductor 11.

  When the camera module is transported or assembled, or when the focus is adjusted, a bending force is applied to the flexible substrate 10. When this bending force is applied in the direction of the arrow Z shown in FIG. The flexible substrate 10 bends at the position of the bending induction portion 14.

  As the inducing portion 14 bends, the reinforcing portion 15 positioned between the inducing portion 14 and the one end 5a of the circuit board 5 bends gently as a bending allowance, and the bending stress is dispersed. Thus, the stress concentration of the flexible substrate 10 does not occur at the one end 5a of the lead wire 5, so that the lead conductor 11 without disconnection can be obtained.

  FIG. 4 shows a second embodiment of the flexible substrate mounting structure according to the present invention. The second embodiment will be described. The induction portion 14 is insulated with the insulating film 12 on the lead conductor 11 left. This is formed by the removal portion 13 provided in the film 12.

  That is, the removal portion 13 that is the induction portion 14 is provided, and the insulating film 12 that covers the lead conductor 11 is left between the removal portions 13. The structure is the same as that of the first embodiment, and the same parts are denoted by the same reference numerals, and the description thereof is omitted here.

  FIG. 5 shows a third embodiment of the flexible substrate mounting structure of the present invention. The third embodiment will be described. The inducing portion 14 is placed on the flexible substrate 10 while avoiding the position of the lead conductor 11. It is formed by the plurality of holes 16 provided in a single row.

  As shown in the third embodiment of FIG. 5, the holes 16 are provided in both the flexible substrate 10 and the insulating film 12, or the first embodiment of FIG. 2 and the second embodiment of FIG. The hole 16 may be provided at the position of the removal portion 13 of the insulating film 12.

  Other configurations have the same configurations as those of the above-described embodiment, and the same parts are denoted by the same reference numerals, and the description thereof is omitted here.

It is principal part sectional drawing which concerns on 1st Example of the attachment structure of the flexible substrate of this invention. It is a top view of the flexible substrate which concerns on 1st Example of the attachment structure of the flexible substrate of this invention. It is explanatory drawing which shows the state which concerns on 1st Example of the attachment structure of the flexible substrate of this invention, and the flexible substrate was bent. It is a top view of the flexible substrate which concerns on 2nd Example of the attachment structure of the flexible substrate of this invention. It is a top view of the flexible substrate which concerns on 2nd Example of the attachment structure of the flexible substrate of this invention. It is principal part sectional drawing of the attachment structure of the conventional flexible substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Attachment member 2 Lens 3 Holding member 4 Infrared removal filter 5 Circuit board 5a One end 6 Land part 7 Connection conductor 8 Imaging element 9 Electrode 10 Flexible board 11 Leading conductor 11a Terminal part 12 Insulating film 13 Removal part 14 Induction part 15 Strengthening part 16 Hole

Claims (8)

A circuit board provided with a land part, a strip-like flexible board having a lead conductor connected to the land part, and the flexible board is overlapped with the circuit board, and the flexible board is one end of the circuit board. In what is attached to the circuit board protruding from
The flexible substrate is provided at a position near the one end away from the one end of the circuit board, a bending inducing portion having a bending strength weaker than the surroundings, a bending strength stronger than the inducing portion, and adjacent to the inducing portion. A flexible substrate mounting structure, comprising: a reinforcing portion provided between the inducing portion and the one end. The flexible substrate mounting structure according to claim 1, wherein the inducing portion is provided in a direction orthogonal to a protruding direction of the flexible substrate. The flexible substrate mounting structure according to claim 1, wherein the flexible substrate is provided with an insulating film covering the lead conductor, and the inducing portion is formed by a removing portion of the insulating film. 4. The flexible substrate mounting structure according to claim 3, wherein the removal portion of the insulating film is provided over the entire width in a direction orthogonal to the protruding direction of the flexible substrate. The flexible substrate mounting structure according to claim 3, wherein the inducing portion is formed by the removing portion provided on the insulating film while leaving the insulating film on the lead conductor. 6. The flexible substrate mounting structure according to claim 3, wherein the insulating film is interposed between the circuit substrate and the flexible substrate. The flexible substrate mounting structure according to claim 1, wherein the flexible substrate is provided with a plurality of holes, and the induction portion is formed by the holes. The image pickup device for a camera module is connected to the circuit board, and a signal from the image pickup device is derived through the flexible substrate. The flexible substrate mounting structure described in 1.

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