JP2012174855A - Flexible printed board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent disconnection of a copper foil pattern without deteriorating workability when inserting a connector.SOLUTION: In a flexible printed board 10, a reinforcing plate 15 provided on a back surface of a terminal exposure part 12a of the base material 11 includes a base part 15a having high rigidity as a whole and a flexible part 15b whose thickness changes. The reinforcing plate 15 is constituted by laminating thin and long reinforcing tapes 16a-16e of different lengths and bonding them with an adhesive 17. When inserting the flexible printed board 10 to the connector, in the case that there is no sufficient work space, the base material 11 is bent near the inner side terminating part of the reinforcing plate 15 and the part is pushed with a finger in an inserting direction. At the time, since the base material 11 is elastically supported from the back side by the flexible part 15b of the reinforcing plate 15, the base material 11 is bent in a circular arcuate state and a folding line is not formed. Thus, the disconnection of a copper foil pattern 12 is prevented.

Description

  The present invention relates to a flexible printed circuit board, and more particularly to a flexible printed circuit board that performs electrical connection between units accommodated in an apparatus using a copper foil pattern for wiring printed on a flexible base material.

  In a device such as a handheld terminal that is desired to be reduced in size and weight, a flexible printed board is used for three-dimensional wiring that saves wiring space or wiring to a movable part in addition to simple connection between units.

  8A and 8B are diagrams showing the flexible printed circuit board, in which FIG. 8A is a plan view showing the appearance of the flexible printed circuit board, FIG. 8B is a side view showing the appearance of the flexible printed circuit board, and FIG. It is a partial expanded sectional view which shows a part.

  The flexible printed circuit board 100 has a copper foil pattern 102 for wiring printed on a thin resin base material 101. On the surface on which the copper foil pattern 102 of the base material 101 is formed, except for lead portions at both ends, A protective cover lay material 104 is attached with an adhesive 103. The lead portion is a portion that is inserted into the connector and electrically connected to the contact, and the terminal by the copper foil pattern 102 is exposed.

  The lead portion has a reinforcing plate 106 attached to the surface of the base 101 opposite to the terminal exposed portion by an adhesive 105. The reinforcing plate 106 is longer than the length of the terminal exposed portion, and extends from the end surface of the base material 101 to the inside beyond the end surface of the coverlay material 104. As a result, the position of the end face of the coverlay material 104 that is easily bent is reinforced by the reinforcing plate 106, so that the base material 101 is bent at the corner portion of the end face of the coverlay material 104 and the copper foil pattern 102 is cut off. Is preventing.

FIG. 9 is a diagram showing a state in which the flexible printed board is inserted into the connector, and FIG. 10 is a diagram showing another state in which the flexible printed board is inserted into the connector.
The connector 111 mounted on the circuit board 110 is of a type in which the internal contact is brought into electrical contact with the copper foil pattern 102 of the terminal exposed portion by press-fitting the lead portion of the flexible printed circuit board 100. For this reason, when connecting the flexible printed circuit board 100 to the connector 111, as shown in FIG. 9, the lead portion is press-fitted into the connector 111 by pressing the inner end portion of the reinforcing plate 106 with a finger through the base material 101. ing.

  By the way, the work space for inserting the flexible printed circuit board 100 into the connector 111 may be narrow due to recent downsizing of the apparatus. In such a case, if a force that bends the inner terminal portion of the reinforcing plate 106 is excessively applied to the base material 101 during insertion into the connector 111, the base material 101 is pushed at the corner portion of the terminal portion, and the copper foil The pattern 102 may be disconnected. Moreover, even if it does not lead to a disconnection, when the base material 101 is bent at a right angle, the copper foil pattern 102 at that portion is partially broken, and a sufficient current capacity may not be obtained.

  For this reason, in assembly drawings or the like, when inserting the flexible printed board 100 into the connector 111, it is instructed not to apply force to the inner end portion of the reinforcing plate 106, or special tweezers 112 are used as shown in FIG. I do. Since the tweezers 112 moves the lead portion of the flexible printed circuit board 100 in the insertion direction while sandwiching the lead portion in the thickness direction, a force that breaks the copper foil pattern 102 is not applied to the lead portion. However, since the work is performed using the tweezers 112, workability when the flexible printed circuit board 100 is inserted into the connector 111 is deteriorated.

  On the other hand, a technique is known in which the force is not concentrated on the inner terminal portion of the reinforcing plate when the lead portion of the flexible printed board is pushed into the connector with a finger (see, for example, Patent Document 1). According to Patent Document 1, the inner end portion of the reinforcing plate is shaped so as not to be orthogonal to the insertion direction so as to disperse the force in the insertion direction.

JP 2000-124573 A

  However, the force applied in the insertion direction at the inner end of the reinforcing plate can be dispersed and reduced, but the corners of the reinforcing plate provided to increase the mechanical strength of the lead portion are inserted through the base material in the insertion direction. Since the force is received, there is a problem that the copper foil pattern cannot be disconnected.

  This invention is made in view of such a point, and provides the flexible printed circuit board which can prevent the disconnection of a copper foil pattern before the workability | operativity at the time of inserting in a connector deteriorates. With the goal.

  In the present invention, in order to solve the above-mentioned problem, a resin base material, a copper foil pattern for wiring formed on the base material, and terminal exposure that becomes a connection terminal at the terminal portion of the base material The protective coverlay material arranged so as to cover the copper foil pattern except for the portion, and the base at a position corresponding to the terminal exposed portion on the surface opposite to the side where the coverlay material is arranged A reinforcing plate provided on the material, wherein the reinforcing plate is disposed on the terminal end side of the base material and has a higher rigidity than the base material, and the base terminal end portion of the base part There is provided a flexible printed board characterized in that the flexible printed circuit board is configured with a flexible portion that is disposed on the opposite side of the base portion and has higher flexibility than the base portion.

  According to such a flexible printed circuit board, when inserting the terminal exposed portion into the connector, the substrate is bent in the vicinity of the inner end portion of the reinforcing plate and the portion is pushed with a finger, but supported by the reinforcing plate having the flexible portion. By doing so, the substrate is bent into an arc shape. Thereby, since the part pressed also with a finger | toe with a copper foil pattern is bend | folded in circular arc shape, a disconnection can be prevented beforehand.

  The flexible printed circuit board with the above configuration has flexibility at the inner end portion of the reinforcing plate, so that when the substrate is bent, the base material will not be deformed so as to be creased at the corners of the reinforcing plate. There is an advantage that the pattern breakage of the pattern can be eliminated. Further, even in connection work in a narrow place, work can be performed with a finger without using a jig, so workability is not deteriorated.

It is a figure which shows the flexible printed circuit board which concerns on 1st Embodiment, Comprising: (A) is a top view which shows the external appearance of a flexible printed circuit board, (B) is a side view which shows the external appearance of a flexible printed circuit board, (C) is It is a partial expanded sectional view which shows the lead part of a flexible printed circuit board. It is a figure which shows the insertion state to the connector of the flexible printed circuit board concerning 1st Embodiment. It is a partial expanded sectional view which shows the lead part of the flexible printed circuit board concerning 2nd Embodiment. It is a figure which shows the insertion state to the connector of the flexible printed circuit board which concerns on 2nd Embodiment. It is a partial expanded sectional view which shows the lead part of the flexible printed circuit board concerning 3rd Embodiment. It is a figure which shows the insertion state to the connector of the flexible printed circuit board concerning 3rd Embodiment. It is a partial expanded sectional view which shows the lead part of the flexible printed circuit board concerning 4th Embodiment. It is a figure which shows a flexible printed circuit board, Comprising: (A) is a top view which shows the external appearance of a flexible printed circuit board, (B) is a side view which shows the external appearance of a flexible printed circuit board, (C) shows the lead part of a flexible printed circuit board. It is a partial expanded sectional view. It is a figure which shows the insertion state to the connector of a flexible printed circuit board. It is a figure which shows another insertion state to the connector of a flexible printed circuit board.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, taking as an example a case where the present invention is applied.
1A and 1B are diagrams showing a flexible printed circuit board according to the first embodiment, wherein FIG. 1A is a plan view showing the appearance of the flexible printed circuit board, and FIG. 1B is a side view showing the appearance of the flexible printed circuit board. C) is a partially enlarged cross-sectional view showing a lead portion of a flexible printed circuit board.

  The flexible printed circuit board 10 according to the first embodiment has a long and thin resin base material 11, a copper foil pattern 12 for wiring formed thereon, and an adhesive covering the copper foil pattern 12. And a protective coverlay material 14 affixed with the agent 13. The coverlay material 14 is not affixed to the portion to be inserted into the connector in the lead portions at both ends of the flexible printed circuit board 10, and the copper foil pattern 12 is exposed. The exposed portion of the copper foil pattern 12 constitutes a terminal exposed portion 12a that is electrically connected to a contact provided therein when inserted into the connector.

  The lead portion of the flexible printed board 10 has a reinforcing plate 15 attached to the base material 11 at a position corresponding to the terminal exposed portion 12a on the surface opposite to the side on which the coverlay material 14 is attached. For example, the reinforcing plate 15 is configured by laminating a plurality of (in the illustrated example, five) thin reinforcing tapes 16 a to 16 e that are reinforcing members and bonding them together with an adhesive 17. 11 is attached. Thereby, the flexible printed circuit board 10 becomes a lead part in which the base 11 having the thickness of the reinforcing plate 15 and the thickness of the copper foil pattern 12 are inserted into the connector.

  The reinforcing tapes 16 a to 16 e of the reinforcing plate 15 are slightly different in the longitudinal dimension of the copper foil pattern 12. The reinforcing tape 16a closest to the base material 11 is the longest, and the reinforcing tape 16b, the reinforcing tape 16c, the reinforcing tape 16d, and the reinforcing tape 16e are shortened in this order as the distance from the base material 11 increases. However, the shortest reinforcing tape 16e is formed to be equal to the length of the terminal exposed portion 12a or longer than the length of the terminal exposed portion 12a. Accordingly, the reinforcing plate 15 is separated from the base portion 15a having a certain thickness on the terminal end side of the flexible printed circuit board 10 and having a rigidity higher than that of the base material 11, and the thickness changing stepwise. Accordingly, the flexible portion 15b having increased flexibility is integrally formed.

  Here, the dimension of each element which comprises the flexible printed circuit board 10 is mentioned as an example. The base material 11 has a thickness of 25 μm, the copper foil pattern 12 has a thickness of 12 μm, the adhesive 13 and the coverlay material 14 each have a thickness of 25 μm, and the length of the terminal exposed portion 12a is 3. 0 millimeters (mm). In the reinforcing plate 15, the reinforcing tapes 16 a to 16 e and the adhesives 17 and 18 each have a thickness of 25 μm, and the thickness of the connector fitting portion including the base material 11 and the copper foil pattern 12 is 287 μm. The reinforcing tape 16a has a length of 7.0 mm, and the lengths of the reinforcing tape 16b, the reinforcing tape 16c, the reinforcing tape 16d, and the reinforcing tape 16e are shorter by 0.7 mm than the reinforcing tape 16a. Accordingly, the reinforcing plate 15 has a length of the base portion 15a of 4.2 mm, a length of the flexible portion 15b of 2.8 mm, and the length of the overlap 19 of the base portion 15a from the end portion of the coverlay material 14 is It is 1.2 mm. Since the base portion 15 a of the reinforcing plate 15 is longer than the length of the terminal exposed portion 12 a by the length of the overlap 19, the base material 11 is reinforced by the base portion 15 a at the position of the end surface of the cover lay material 14 and is made of copper. Pattern cutting of the foil pattern 12 is prevented. In addition, about the length of the terminal exposure part 12a, and the thickness of a connector fitting part, it is a dimension which satisfy | fills the requirement designated beforehand on the specification of the connector.

  The reinforcing plate 15 has a high flexibility as the flexible portion 15b formed integrally with the base portion 15a moves toward the inner end portion. For this reason, when an external pressure is applied to the base material 11 in the vicinity of the inner terminal portion and the base material 11 is bent, the flexible portion 15b is also bent together. In particular, since the inner terminal portion of the reinforcing plate 15 having the highest flexibility cannot stand up to the bending of the base material 11, the base material 11 may be bent at the corners of the reinforcing plate 15 so as to be creased. There is no. In addition, when only the base portion 15a of the reinforcing plate 15 is bonded and the flexible portion 15b is not bonded, the flexibility of the flexible portion 15b becomes higher.

FIG. 2 is a diagram showing a state in which the flexible printed circuit board according to the first embodiment is inserted into the connector.
When the flexible printed circuit board 10 is inserted into a connector 21 mounted on the circuit board 20, the copper foil pattern 12 of the terminal exposed part 12 a is brought into electrical contact with contacts inside the connector 21. When the lead portion of the flexible printed board 10 is inserted into the connector 21, the base material 11 is bent in the vicinity of the inner terminal portion of the reinforcing plate 15, and the portion is pushed with a finger in the insertion direction of the connector 21. At this time, since the base material 11 is elastically supported from the back side by the flexible portion 15b of the reinforcing plate 15, the base material 11 is bent in an arcuate state and is not creased. Therefore, even when the substrate 11 is pushed while being bent in a narrow place where the lead portion cannot be picked with a finger and inserted into the connector 21, stress is not concentrated on the copper foil pattern 12, Disconnection of the copper foil pattern 12 can be prevented in advance.

  FIG. 3 is a partially enlarged sectional view showing a lead portion of the flexible printed circuit board according to the second embodiment, and FIG. 4 is a view showing an insertion state of the flexible printed circuit board according to the second embodiment into the connector. 3 and 4, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  According to the flexible printed circuit board 10 a according to the second embodiment, the reinforcing plate 15 is configured by stacking reinforcing tapes 16 a to 16 e having the same size and bonding them with an adhesive 17. At this time, the adhesive 17 does not bond the entire surfaces of the reinforcing tapes 16a to 16e, but bonds only a part of the outer end portion side. As a result, the bonded region constitutes the base portion 15 a of the reinforcing plate 15, and the non-bonded region constitutes the flexible portion 15 b of the reinforcing plate 15.

  When the lead portion of the flexible printed circuit board 10a is inserted into the connector 21, it is pushed with a finger in the insertion direction of the connector 21 while bending the base material 11 near the inner terminal portion of the reinforcing plate 15. At this time, the flexible plate 15 is bent in accordance with the bending of the base material 11 of the reinforcing plate 15. Since the reinforcing tapes 16a to 16e in the flexible portion 15b are not bonded to each other, the reinforcing tapes 16a to 16e are bent out of alignment with each other and elastically support the base material 11 from the back side in this state. For this reason, since the base material 11 is bend | folded in circular arc shape, the disconnection of the copper foil pattern 12 can be prevented beforehand.

  FIG. 5 is a partial enlarged cross-sectional view showing a lead portion of a flexible printed circuit board according to the third embodiment, and FIG. 6 is a view showing a state in which the flexible printed circuit board according to the third embodiment is inserted into a connector. 5 and 6, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  According to the flexible printed circuit board 10b according to the third embodiment, the reinforcing plate 15 is made of a porous material that is foam-molded to a certain thickness. This porous material is partially impregnated with an adhesive, cured and modified to form the base portion 15a, and the unmodified region forms the flexible portion 15b.

  When inserting the lead portion of the flexible printed circuit board 10b into the connector 21, the finger is pushed in the insertion direction of the connector 21 while bending the base material 11 near the inner terminal portion of the reinforcing plate 15. At this time, in the reinforcing plate 15, the uncured flexible portion 15b is bent in accordance with the bending of the substrate 11, and elastically supports the substrate 11 from the back side. For this reason, since the base material 11 is not deform | transformed so that a crease may be attached only by bending in circular arc shape, the disconnection of the copper foil pattern 12 can be prevented beforehand. The base portion 15a may be configured to be more easily bent into an arc shape by gradually changing the amount impregnated with the adhesive from the inner end portion and modifying it so as to be gradually cured. Conversely, a rigid porous material is partially impregnated with a softening agent, softened and modified to constitute the flexible portion 15b, and the unmodified region is used as the reinforcing plate 15 of the base portion 15a. Also good.

  FIG. 7 is a partially enlarged cross-sectional view showing a lead portion of a flexible printed circuit board according to the fourth embodiment. In FIG. 7, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  According to the flexible printed circuit board 10c according to the fourth embodiment, the reinforcing plate 15 is a tape-shaped material that is a single reinforcing material thicker than the flexible printed circuit board 10 according to the first embodiment. The flexible portion 15b is configured by processing the inner terminal portion. That is, the flexible portion 15b of the reinforcing plate 15 is formed such that the thickness is continuously reduced from the base portion 15a having a certain thickness to the inner terminal portion, and the flexibility is increased toward the inner terminal portion. . In the illustrated example, the thickness of the flexible portion 15b is linearly changed, but may be changed in a curved manner.

  The reinforcing plate 15 has physical characteristics almost the same as those of the flexible printed board 10 according to the first embodiment. That is, when the lead portion of the flexible printed circuit board 10c is inserted into the connector 21, the inner terminal portion of the flexible portion 15b having the highest flexibility is greatly deformed together with the base material 11 as shown in FIG. The material 11 does not reach a crease. Therefore, since stress does not concentrate on the copper foil pattern 12, the copper foil pattern 12 is prevented from being disconnected.

DESCRIPTION OF SYMBOLS 10, 10a, 10b, 10c Flexible printed circuit board 11 Base material 12 Copper foil pattern 12a Terminal exposure part 13 Adhesive 14 Coverlay material 15 Reinforcement plate 15a Base 15b Flexible part 16a-16e Reinforcement tape 17, 18 Adhesive 19 Overlap 20 Circuit board 21 Connector

Claims (6)

A resin base material;
A copper foil pattern for wiring formed on the substrate;
A protective coverlay material disposed so as to cover the copper foil pattern except for the terminal exposed portion serving as a connection terminal at the terminal portion of the base material,
A reinforcing plate provided on the base material at a position corresponding to the terminal exposed portion on the surface opposite to the side where the coverlay material is disposed;
With
The reinforcing plate is disposed on the terminal portion side of the base material and has a rigidity higher than that of the base material, and is disposed on the opposite side of the base material from the terminal portion of the base material and more than the base portion. A flexible printed board comprising a flexible portion having high flexibility.   The flexible printed circuit board according to claim 1, wherein the base portion has at least the length of the terminal exposed portion.   The reinforcing plate has a plurality of reinforcing materials that are laminated and bonded to each other, and the length of the reinforcing material from the end portion of the base material is shortened as the distance from the base material increases, thereby increasing the thickness of the stacking. The flexible printed circuit board according to claim 1, wherein the flexible portion is configured by being changed stepwise.   The reinforcing plate has a plurality of reinforcing materials that are laminated and bonded to each other, the reinforcing material is bonded to each other only at the base portion, and the flexible portion is configured by the reinforcing materials that are not bonded to each other. The flexible printed circuit board according to claim 1.   The reinforcing plate includes a porous material having a certain thickness, and the porous material is partially impregnated with an adhesive and cured to form the base, and the region not impregnated with the adhesive. The flexible printed circuit board according to claim 1, wherein the flexible part is configured as described above.   The said reinforcement board comprised the said flexible part by thickness reducing as it leaves | separated in the direction opposite to the terminal part of the said base material from the said base part which has fixed thickness, The flexible part was comprised. Item 8. A flexible printed circuit board according to Item 1.

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