JP2005243968A - Flexible rigid substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible rigid substrate enhanced in anti-discontinuity or anti-fracture when bent. <P>SOLUTION: This substrate has a curved shape at the edge of the opposite side to the leading direction of a rigid substrate 6 positioned at the leading edge of a flexible layer F, namely, it has a curved shape 7 at the edge of the center in the flexible layer F. In addition, the corner 8 of both sides of the edge is curved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a flexible rigid substrate comprising a flexible layer in which a conductor pattern is sandwiched in the thickness direction with a flexible insulating film, and a rigid substrate disposed on at least one outer principal surface of an end region of the flexible layer. Is.

In recent years, FPC (flexible printed circuit), FFC (flexible flat cable), and flexible rigid boards with flexible functions on printed boards are often used to make electrical connections inside electronic devices. ing.

  A flexible rigid substrate is a flexible layer in which a conductor pattern is sandwiched in the thickness direction by a flexible insulating film, and a glass cloth base epoxy resin (glass epoxy) attached to a part of one outer main surface of the flexible layer. It is comprised from the rigid board | substrate which consists of these. The rigid substrate is formed only in one or both end regions of the flexible layer. In other words, the printed circuit board has flexibility as a whole because it is composed of only the flexible layer and is not provided with a rigid board in the central region of the flexible layer.

  Such a flexible rigid board is usually used as a connection cable in order to electrically connect a printed circuit board and equipment components inside equipment such as electronic equipment and communication equipment. For example, a connector for inserting a rigid board of a flexible rigid board is provided on a printed circuit board or an equipment component disposed inside the equipment, and the rigid board of the flexible rigid board is inserted into this connector, so that the printed circuit board or the equipment is inserted. The connection of components etc. was achieved.

  However, a flexible rigid board can form a flexible layer on the board itself, and a connector connection terminal can be formed at the tip of the flexible layer, so that the number of parts inside the device can be reduced, and the board is effective for overall cost reduction. It is.

  A conventional flexible rigid substrate will be described with reference to FIGS.

  The flexible rigid substrate 80 includes, for example, a flexible layer F in which the conductive pattern 83 is sandwiched between two flexible insulating films 82 and 84 in the thickness direction, and at least one outer main surface of the end region of the flexible layer F. And a rigid substrate 63 disposed on the substrate.

  As described above, in order to electrically connect the printed circuit board and the connector of the equipment component inside the equipment, the opposite surface (the other outside main) of the flexible layer F to which the rigid board 63 is attached is provided. Only the flexible insulating film 84 was removed from the end portion, and the conductor pattern 3 was exposed. The conductor pattern 3 exposed from the flexible layer F becomes the end electrode portion 85.

  In the figure, a flexible insulating film 82 is a base film made of polyimide or the like, and a plurality of conductor patterns 83 are arranged in parallel on the flexible insulating film 82 which is the base film. The conductor pattern 83 is covered with a cover film made of polyimide, which is a flexible insulating film 84.

 A rigid substrate 63 made of polyester or the like is disposed on the flexible insulating film 82 via an adhesive layer.

The rigid substrate 63 serves as a knob for reinforcing the tip of the flexible layer F and facilitating the insertion / removal operation to / from a connector or the like. Such a structure is proposed in Japanese Patent Application Laid-Open No. 2003-3299, for example.

  By the way, the flexible rigid board 80 is inserted into and removed from the connector in order to electrically connect a printed circuit board and equipment components arranged inside the electronic equipment and communication equipment. For example, it is used for connection with a component part of a movable part inside the device, and therefore the bending is always repeated at the flexible layer F portion.

  For example, if bending is repeated in the flexible layer F of the flexible rigid substrate 80, stress is repeatedly generated in the rigid substrate 63, and the conductor pattern 83 held between the flexible insulating films 82 and 84 is disconnected, or the flexible circuit substrate 80 itself. There was a problem of tearing.

In order to solve these problems, the shape of the end portion of the rigid substrate 63 is changed to a jagged shape Z as shown in FIG. 9, or the thickness of the rigid substrate 63 is gradually decreased from the central portion side of the flexible layer F. Was. Thereby, the end portion from the central portion of the flexible layer F of the rigid substrate 6 is made flexible.
Japanese Patent Laid-Open No. 2003-3299

  However, in the flexible rigid substrate 80, when the electrode terminal portion 85 intended for electrical connection is formed at the tip portion of the substrate, the rigid substrate 63 disposed there is not only polyester but also a highly rigid glass cloth base epoxy. Resin materials are also frequently used.

  Even when the central side edge shape of the flexible layer F of the rigid substrate 63 is changed to the jagged shape Z or the thickness of the end portion is controlled, when the connector is inserted into or removed from the connector, stress is mainly applied from various directions. However, this stress cannot be eliminated with flexibility.

  As shown in FIG. 11, when the connector is inserted into and removed from the connector, a stress is generated to bend the flexible rigid board in the direction of the insertion / removal mainly by arrows a, b, and c.

  That is, in a jagged portion, when stress is applied from the direction of the arrow a, stress is generated in the broken line A portion at the end of the rigid substrate 63. Similarly, when stress is applied from the direction of the arrow b, the broken line B portion at the end of the rigid substrate 63 In addition, when stress is applied from the direction of the arrow c, stress is generated in the broken line C portion at the end of the rigid substrate 63.

  Further, according to the jagged structure, for example, when stress is applied from the direction close to the arrows a and c, the location where the stress is generated on the flexible rigid substrate 80 is the broken line A which is the convex portion at the end of the jagged shape as described above. When the stress is applied from the direction close to the arrow c, the stress is similarly generated in the broken line C part.

  Further, as can be seen from the fact that the broken line A and the broken line B part are included in the broken line C, the broken line A part and the broken line C part always cause stress when the flexible rigid board 80 is bent, The conductor pattern and the flexible layer which are inherent in the flexible rigid substrate 80 are easily broken or torn. In particular, this tendency is prominent when a glass cloth base epoxy resin having high rigidity, which is convenient when functioning as a knob when a connector is inserted or removed, is used for a rigid substrate.

  The present invention has been devised in view of the above-mentioned problems, and its purpose is to alleviate the stress concentrated on the boundary portion between the flexible layer and the rigid substrate in the flexible rigid substrate, and to break the conductor pattern, or An object of the present invention is to provide a flexible rigid substrate that can prevent the flexible layer itself from being torn.

  Another object of the present invention is to provide a flexible rigid board having high operability when being inserted into and removed from a connector as a connector cable.

  The present invention relates to a flexible rigid substrate comprising a flexible layer formed by sandwiching a conductive pattern in the thickness direction with a flexible insulating film, and a rigid substrate disposed on at least one outer principal surface of an end region of the flexible layer. The flexible rigid substrate is characterized in that the shape of the edge of the rigid substrate on the center side of the flexible layer is an arc shape.

  Another invention comprises a flexible layer formed by sandwiching a conductor pattern in the thickness direction with a flexible insulating film, and a rigid substrate disposed on at least one outer principal surface of the end region of the flexible layer. The flexible rigid substrate is characterized in that the corners at both ends of the flexible substrate center side edge of the rigid substrate are curved.

Moreover, in any case, it is a flexible rigid board | substrate which comprised the rigid board | substrate with the glass cloth base-material epoxy resin board | substrate.

  As described above, according to the present invention, the conductor pattern is disconnected due to bending at the boundary between the rigid substrate and the flexible portion in the flexible rigid substrate, or the boundary between the substrate portion and the flexible portion in the flexible rigid substrate, or the flexible portion is broken. To solve this problem, the edge of the rigid substrate at the center of the flexible layer has an arc shape, and the corners at both ends of the edge are curved to disperse the stress generated in this part in all directions. It is possible to effectively prevent disconnection of the conductor pattern that occurs at the boundary with the rigid substrate and tearing that occurs in the flexible layer from both sides of the end of the rigid substrate.

  Further, since a rigid substrate made of a glass cloth base epoxy resin material is used as the rigid substrate, when the flexible rigid substrate is inserted into and removed from the connector, it can function as a knob, which is very easy to handle. .

  Hereinafter, a flexible rigid substrate of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a partial plan view on the side where a rigid substrate is disposed at the tip of the flexible rigid substrate of the present invention, FIG. 2 is a partial plan view on the side where electrode terminals are formed, and FIG. 3 is a diagram of the flexible rigid substrate. It is sectional drawing of a front-end | tip part.

  The flexible rigid substrate 1 is arranged on at least one outer main surface of a flexible layer F formed by sandwiching the conductor pattern 3 in the thickness direction between the flexible insulating films 2 and 4 and an end region of the flexible layer F. It consists of a rigid substrate 6.

The flexible insulating film 2 of the flexible rigid substrate 1 is made of, for example, polyimide and is the base film 2 of the flexible layer F.

  And on the flexible insulating film 2 which is this base film, the some conductor pattern 3 which consists of copper, for example is arranged in parallel. In addition, a flexible insulating film 4 that is a cover film made of polyimide or the like is formed so as to cover the plurality of conductor patterns 3.

  And the edge part of the flexible insulating film 4 by the side of this cover film has removed a part of cover film 4, and the edge part of the conductor pattern 3 was exposed from this removal part, and this exposed part was carried out. The conductor pattern 3 becomes the electrode terminal portion 5.

  A rigid substrate 6 made of a glass cloth base epoxy resin material is disposed on the outer principal surface of the flexible layer F on the base film side in the end region of the flexible layer F via an adhesive layer. The distal end of the rigid substrate 6 coincides with the distal end of the flexible layer F, and the width of the rigid substrate 6 coincides with the width of the flexible layer F.

  Moreover, the flexible substrate F center side edge shape of the rigid board | substrate 6 has comprised the circular arc shape 7, and has comprised the shape where the center of the width direction protrudes. That is, the end shape of the rigid substrate 6 on the side opposite to the distal end direction (side to be inserted into the connector) (center side of the flexible layer F) is an arc shape 7, and preferably the width of the rigid substrate 6 is set to the diameter. The arc shape 7 as shown in FIG. The rigid substrate 6 functions as a knob for reinforcing the tip of the flexible rigid substrate 1 and inserting / removing the connector into a connector or the like.

  As shown in FIG. 4, the flexible rigid substrate 1 having the rigid substrate 6 having such a shape is subjected to stress from various directions in the insertion / removal direction of the connector.

  In FIG. 4, arrows a, b, and c show examples of stresses generated by bending of the flexible circuit board. For example, when stress is applied from the direction of the arrow a to the broken line A portion at the end of the rigid substrate 6, when stress is applied from the direction of the arrow b to the broken line B portion at the end of the rigid substrate 6, the rigid substrate Stress concentrates on the broken line C at the six ends.

  Here, even when stress is applied from the direction of the arrow b, strong stress does not occur in the broken line A portion and the broken line C portion.

  Further, in such a structure, for example, when stress is applied from a direction close to each arrow, the stress is concentrated at the same place as shown by a broken line A portion in FIG. 11 that explains the generation of stress in the conventional structure. Absent. That is, the stress generated at the end of the rigid substrate 6 is dispersed with respect to the stress applied from various directions when the flexible circuit board is inserted into and removed from the connector.

  Thereby, compared with the flexible rigid board | substrate 80 which has the conventional structure, the conductor pattern 3 pinched | interposed with the flexible insulating films 2 and 4 becomes difficult to disconnect, and the flexible layer F itself becomes difficult to tear.

  5 and 6 relate to a deformed structure of the rigid substrate 6 and the flexible layer F. FIG. 1 to 3, only one conductor pattern 3 is formed in the flexible layer F, but a plurality of conductor patterns 3 may be formed in the thickness direction in the flexible layer F.

  Moreover, you may form the rigid board | substrate arrange | positioned at one outer main surface of the edge part of the flexible layer F in both main surfaces. Moreover, you may form a rigid board | substrate in the both ends of a flexible layer.

  Furthermore, an internal conduction through hole may be formed in each rigid substrate, and a conductor pattern may be formed on the surface. Further, the rigid substrate itself may have a laminated structure, and a conductor pattern may be formed therein. As a result, the conductor pattern formed on the surface of the rigid board can be used as an electrode terminal part for connecting to the connector, or a circuit that performs a predetermined operation on the flexible rigid board itself by mounting each surface mount component on the conductor pattern on the surface. Can be formed.

  FIG. 5 is a cross-sectional structural view of a flexible rigid substrate having the above-described matters. FIG. 6 is a partial plan view on the rigid substrate side arranged at one end of the flexible rigid substrate.

  The flexible layer F in FIG. 6 is formed with a conductive pattern 3 in the thickness direction on both surfaces of a base film 34 which is a flexible insulating film made of polyimide or the like, and is further a polyimide flexible insulating film on both sides thereof. The cover films 4 and 35 are sandwiched. That is, the conductive pattern 3 of the flexible layer F itself has a laminated structure and achieves a high density conductor.

  Rigid substrates 21, 22, 23, and 24 made of a glass cloth base epoxy resin material are formed on both outer principal surfaces of both ends of the flexible layer F.

  For example, the rigid substrates 21 and 22 arranged at one end of the flexible layer F have a single-layer structure, but an internal conduction through hole 25 is formed therein. The conduction through hole 25 is connected to the conductor pattern 3 of the flexible layer F and leads the conduction pattern 3 to the surfaces of the rigid substrates 21 and 22. A predetermined surface wiring pattern 26 is formed on the surfaces of the rigid substrates 21 and 22 as necessary. The surface wiring pattern 26 can function as a terminal electrode when connected to the connector, and can function as a pad on which a predetermined surface mounting component is mounted.

  In the rigid substrate 22, a notch is formed on one end of the flexible layer F, and the cover film 4 is also removed from the notch, and the conductor pattern 3 on the lower side of the figure is exposed. doing. And the exposed part of this conductor pattern 3 becomes the terminal electrode part 5 which carries out contact conduction to the electrode of a connector.

  For example, the rigid substrates 23 and 24 arranged at the other end of the flexible layer F have a single-layer structure, but an internal conduction through hole 25 is formed therein. The conduction through hole 25 is connected to the conductor pattern 3 of the flexible layer F. The rigid substrates 23 and 24 are also provided with a wiring pattern 27 on the surface connected to the flexible layer F. By using this wiring pattern 27, for example, the pitch and shape of the conductive pattern 3 of the flexible layer F are connected to this wiring pattern 27 through the conductive through hole 25, and the wiring pattern 27 is routed by the wiring pattern 27. And the shape can be changed. The wiring pattern 27 and the conductive through hole 25 can be connected to the surface wiring pattern 26. That is, when the surface wiring pattern 26 is used as a terminal portion, the pitch and shape of the terminal portion that is the surface wiring pattern 26 can be arbitrarily changed according to, for example, the arrangement of the terminal electrode portions connected to the connector. Further, the rigid substrates 21 to 24 themselves have a laminated structure, and the internal wiring pattern and a conductive through hole for connecting the internal wiring patterns, the internal wiring pattern and the surface wiring pattern 26, and the internal wiring pattern and the wiring pattern 27 are connected. Flexible by providing conductive through-holes, and further conductive through-holes (actually including through-holes passing through the thickness direction of the flexible insulating film) that connect each wiring and the conductive pattern of the flexible layer F. A high-density circuit network can be formed on the rigid substrate itself. Of course, the surface wiring pattern 26 can function as a terminal electrode when connected to the connector, and can also function as a pad on which a predetermined surface mounting component is mounted.

  It is important that the end side shape on the center side of the flexible layer F of such rigid substrates 21, 22, 23, 24 is an arc shape 7. Further, in the rigid substrates 21 and 22 or the rigid substrates 23 and 24, when the length of the rigid substrate from the end of the flexible layer F is different, the rigid substrate 21 on the side that is longer toward the central side of the flexible layer F. Alternatively, the end shape of the end portion on the central side of the flexible layer F of any one of the rigid substrates of 22, 23, or 24 may be formed in an arc shape 7. FIG. 7 shows another structure of a rigid substrate used for a flexible rigid substrate.

Both end corners 8 and 8 on the central side edge of the flexible layer F of the rigid substrate 61 of FIG. 7 are curved. That is, the corner portion is R-processed, and the portion sandwiched between the curved corner portions 8 and 8 is substantially linear. In this way, it is possible to effectively prevent tearing that occurs from both ends of the flexible layer F due to the stress generated when the connector is inserted and removed. Further, for example, the area of the rigid substrate 61 can be made smaller than that of the rigid substrate 6 in which the shape of the central side edge of the flexible layer F is an arc as shown in FIG. 1, and a flexible rigid substrate having a short length can be achieved. .

  It should be noted that the present invention is not limited to the above-described embodiments, and various changes and improvements can be made without departing from the spirit of the present invention.

It is a fragmentary top view of the edge part area | region of the side which has arrange | positioned the rigid board | substrate of the flexible rigid board | substrate of this invention. It is a fragmentary top view by the side of the electrode terminal in the flexible rigid board | substrate of this invention. It is sectional drawing which shows the cross-section of the flexible rigid board | substrate of this invention. It is the schematic explaining the stress which generate | occur | produces when bending the flexible rigid board | substrate of this invention. It is sectional drawing which shows the cross-section which shows the other Example of the flexible rigid board | substrate of this invention. It is the fragmentary top view of the edge part area | region of the side which has arrange | positioned the rigid board | substrate of the other Example of the flexible rigid board | substrate of this invention. It is the fragmentary top view of the edge part area | region which has arrange | positioned the rigid board | substrate of another Example of the flexible rigid board | substrate by this invention. It is the fragmentary top view which looked at the front-end | tip part of the conventional flexible rigid board | substrate from the electrode terminal. It is the fragmentary top view which looked at the front-end | tip part of the conventional flexible rigid board | substrate from the rigid board | substrate. It is sectional drawing which shows the cross-section of the conventional flexible rigid board | substrate. It is the schematic explaining the stress which generate | occur | produces when bending the conventional flexible rigid board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Flexible rigid board | substrate 2 ... Flexible insulating film (base film)
3 ... Conductor pattern 4 ... Flexible insulating film (cover film)
5 .... Electrode terminal part 6, 61 .. Rigid substrate 7 ... Arc 8 ... Curved corner F ... Flexible layer

Claims (3)

In a flexible rigid substrate comprising a flexible layer formed by sandwiching a conductor pattern in the thickness direction with a flexible insulating film, and a rigid substrate disposed on at least one outer main surface of the end region of the flexible layer,
The flexible rigid substrate characterized in that the flexible substrate central side edge shape of the rigid substrate forms an arc shape. In a flexible rigid substrate comprising a flexible layer formed by sandwiching a conductor pattern in the thickness direction with a flexible insulating film, and a rigid substrate disposed on at least one outer principal surface of the end region of the flexible layer,
A flexible rigid substrate characterized in that both corners of the rigid substrate center side edge of the rigid substrate are curved. The flexible rigid substrate according to claim 1, wherein the rigid substrate is made of a glass cloth base epoxy resin substrate.

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