JP2012084590A - Wiring circuit board and lighting fixture for vehicle using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring circuit board excellent in reliability in which a wiring layer does not break even when a wiring width of a board folding portion is narrow.SOLUTION: The wiring circuit board is realized by folding a board 2 along a folding groove as a folding line 6. In this wiring circuit board 1, as to a folding part wiring circuit pattern 4C of a wiring layer 4 positioned on the folding line 6 of the folding groove formed on one surface of the board 2, its both side edges 4Cand 4Cin its wiring width direction obliquely cross the folding line. The folding into an L shape is performed by twisting a board 2B as a folding part relative to a board 2A as a folding counterpart so that sets of both side edges 2Aand 2Bof the both boards do not overlap each other. And thereby, the folding part wiring circuit pattern 4C is lifted from the board 2.

Description

  The present invention relates to a printed circuit board that is used by bending a board on which a wiring layer is formed, and more particularly to a technique for preventing cutting of a wiring layer at a bent portion.

  In recent years, a technique has been proposed in which a printed circuit board having a wiring layer pattern formed on a rigid board is used instead of a flexible printed wiring board having flexibility (for example, Patent Documents 1 and 2). 3 etc.).

  In the technique described in Patent Document 1, a flexible member is obtained by integrally connecting two substrate bodies made of thick synthetic resin with a flexible member that is thin and bendable. Both board main bodies can be bent freely by using as a folding part. In the technique described in Patent Document 2, a plurality of mounting boards on which LED chips are mounted are arranged and arranged with a flexible sheet, and the mounting boards are bent, whereby each mounting board can be bent. In the technique described in Patent Document 3, a plurality of substrates are connected by solder so that the substrates can be bent.

  All of the techniques described in Patent Documents 1 to 3 enable bending by connecting the substrates together via a flexible member, and do not allow the rigid substrate itself to be bent. In recent years, for example, a printed circuit board in which an insulating layer 102 is formed on a substrate 101 made of aluminum as shown in FIG. 6 and a substrate itself on which a wiring layer 103 having a predetermined pattern is formed can be bent. 104 development is required.

  In this printed circuit board 104, a substrate bending groove 105 is formed as a straight groove in the entire substrate width direction on the surface opposite to the surface on which the wiring layer 103 is formed. The wiring layer 103 has a first wiring circuit pattern portion 103A orthogonal to the groove 105, and a second wiring circuit pattern portion 103B corresponding to the portion where the groove 105 is formed and parallel to the groove 105. The wiring pattern has a cross shape.

  When the wiring circuit board 104 is folded in half using the groove 105 as a folding part, the second wiring circuit pattern portion 103B on the folding line 106 indicated by a broken line in FIG. 6 is cut. For this reason, the function of the wiring layer 103 is lost by eliminating the conductive portion of the second wiring circuit pattern portion 103B. Therefore, it is conceivable that conduction is achieved in a portion remaining without being cut by securing a wide wiring width W of the second wiring circuit pattern 103B in a portion corresponding to the groove 105.

Japanese Utility Model Publication No. 63-152260 JP 2010-141200 A JP 2010-135308 A

  However, as shown in FIG. 7, when two wiring layers 103 and 103 are formed on the substrate 101, the wiring width W of the second wiring pattern portion 103B of each of the wiring layers 103 and 103 is increased. It is not possible. For this reason, it is necessary to redesign the wiring layer 103 so that the number of the wiring layers 103 is reduced from one to two because the risk of the second wiring circuit pattern portion 103B corresponding to the groove 105 serving as the bent portion is cut increases. Arise. Further, when the substrate 101 itself needs to be made small, the wiring width of the wiring pattern at the bent portion is naturally reduced, so that the wiring pattern portion can be easily cut.

  Accordingly, an object of the present invention is to provide a highly reliable printed circuit board that does not cut the wiring layer even if the wiring width of the bent portion of the board becomes narrow, and a vehicle lamp using the wiring circuit board.

  According to a first aspect of the present invention, there is provided a printed circuit board in which a wiring layer is formed as a predetermined pattern on an insulating layer formed on one surface of a substrate, and the substrate is bent and used on the other surface of the substrate. A folding groove is formed to bend the wiring layer, and a wiring circuit pattern of the bent portion of the wiring layer located on the line of the bending groove is crossed obliquely on both sides of the wiring width with respect to the line of the bending groove. And when the substrate is folded in a shape of a twisted shape so that both side edges of both substrates do not match each other with respect to the substrate to be folded with the folding groove as a folding line, A bent wiring circuit pattern is raised from the substrate.

  A second aspect of the present invention is the wired circuit board according to the first aspect, wherein the substrate is a conductive metal substrate.

  According to a third aspect of the present invention, an LED is mounted on the wired circuit board according to the first or second aspect, and electrode terminals of the LED are connected to the wiring layer.

  According to the wired circuit board of the present invention, the folded portion wiring circuit pattern of the wiring layer located on the bent groove line is crossed obliquely on both sides of the wiring width with respect to the bent groove line. When the substrate on the side to be bent with respect to the substrate on the side to be bent using the bending groove as a fold line is bent in a U-shape so that both side edges of both substrates do not match, the bent wiring circuit pattern is By floating from the substrate, the wiring layer on the folding line is not cut. In this way, the bent wiring circuit pattern is lifted from the substrate, so that even if the wiring width is reduced, it is difficult to cut.

1A and 1B show a printed circuit board according to the present embodiment, in which FIG. 1A is a plan view thereof, and FIG. FIG. 2 is a right side view of the printed circuit board of FIG. FIG. 3 shows a state in which the printed circuit board of FIG. 2 is bent into a twisted letter shape, (A) is a right side view thereof, and (B) is a board to be bent with respect to the board to be bent. It is the figure which exaggerated and showed a mode that it bends in the shape of a twist so that both edges may not correspond. FIG. 4 is a right side view of the printed circuit board showing a state in which the bent wiring circuit pattern is lifted from the board by bending the printed circuit board of FIG. FIG. 5 shows a vehicular lamp in which an LED is mounted on the printed circuit board of the present embodiment and the electrode terminals of the LED are connected to the wiring layer. FIG. 5A is a perspective view when viewed from the LED mounting surface. ) Is a perspective view when viewed from the wiring layer forming surface. 6A and 6B show a conventional printed circuit board, in which FIG. 6A is a plan view and FIG. 6B is a perspective view when the board is bent. FIG. 7 is a plan view of a conventional printed circuit board in which two wiring layers are formed on a substrate.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.
As shown in FIGS. 1 and 2, the printed circuit board 1 of the present embodiment has a wiring layer 4 formed as a predetermined pattern on an insulating layer 3 formed on one surface 2 a of the substrate 2. The substrate 2 is not a flexible flexible substrate but a conductive metal substrate having rigidity such as aluminum. The thickness of the substrate 2 is, for example, a thick substrate of about 1 mm, but the thickness is not limited to 1 mm.

On the other surface 2 b of the substrate 2, a bending groove 5 for bending the substrate 2 is formed. The bending groove 5 is formed over the entire substrate as a straight groove having a substantially U-shaped cross section in the short side direction indicated by X, where X is the short side direction of the substrate 2 and Y is the long side direction. . In the present embodiment, the position of the bending groove 5 is a position where the long side of the substrate 2 is divided into about two equal parts. Further, the folding groove 5, the length of the long side direction Y parallel side edges 2A ₁ and folded side board 2B of the substrate 2A on the side to be folded when folding the substrate 2 into two folding difficulty of shape It is formed parallel to the short side direction X substantially perpendicular to the side direction Y parallel to side edge 2B _1.

  The wiring layer 4 includes a first wiring circuit pattern 4A formed on the substrate 2A on the side to be bent using the bending groove 5 as the bending line 6, a second wiring circuit pattern 4B formed on the substrate 2B on the bending side, and a bending line. 6 and a bent portion wiring circuit pattern 4C located on the upper portion. The wiring layer 4 is formed into a predetermined wiring circuit pattern by exposing and developing, for example, a copper foil formed on the entire surface of the insulating layer 3 by photolithography. Of course, the wiring layer 4 may be formed by means other than photolithography.

  The first wiring circuit pattern 4A is formed as a rectangular pattern extending in the long side direction Y of the substrate 2, for example. Similarly, the second wiring circuit pattern 4B is formed as a rectangular pattern extending in the long side direction Y of the substrate 2. The first wiring circuit pattern 4 </ b> A and the second wiring circuit pattern 4 </ b> B are not formed on the same line, but are mutually displaced in the short-side direction X of the substrate 2. The bent wiring circuit pattern 4C is an oblique wiring layer that connects the first wiring circuit pattern 4A and the second wiring circuit pattern 4B.

As shown in FIG. 1B, the bent portion wiring circuit pattern 4C crosses the wiring width side edges 4C ₁ and 4C ₂ at an angle θ with respect to the bending line 6 at an angle. The angle θ is preferably less than 90 degrees, and as the angle decreases, the bent wiring circuit pattern 4C is peeled off from the substrate 2 without being cut off. When the angle θ is 90 degrees, when the substrate 2 is bent along the bending line 6, the bent portion wiring circuit pattern 4C is cut without fail, and as the wiring width at that portion becomes narrower, all of the portion is cut.

As shown in FIG. 3, the printed circuit board configured as described above is used by bending the folding groove 5 into a square shape as a folding line 6. When the substrate 2 is folded from the folding line 6, the folded substrate 2B is not folded so as to completely overlap the folded substrate 2A, but the folded state is exaggerated in FIG. As shown, the two substrates 2A and 2B are twisted a little in the direction of the arrow M (or in the opposite direction) so that the two side lines 2A ₁ and 2B _{1 of the} two substrates 2A ₁ and 2B ₁ do not coincide with each other. Bend it. To be a little more detail, bent with respect to opposite side edges 2A ₁ side of the substrate 2A to the opposite side edges 2B ₁ is folded on the side of the substrate 2B, these sides lines 2A ₁ when viewed the other board 2B from one substrate 2A The two substrates 2A and 2B are bent so that the positions of the 2Bs ₁ do not coincide with each other and do not coincide with each other. It is assumed that the bending angle of the two substrates 2A and 2B is an angle that is a square shape, and does not become an acute angle to such an extent that they are overlapped or bent so that they are overlapped.

  The substrate 2B on the side to be bent is twisted with respect to the substrate 2A on the side to be bent so that the substrate 2B can be bent. The width W and the depth H of the bending groove 5 formed on the other surface 2b of the substrate 2 (FIG. 2). It is considered that By setting the width W and the depth H of the bending groove 5 to a certain size, it is possible to bend the substrate 2B on the side to be bent into a square shape with respect to the substrate 2A on the side to be bent.

  When the substrate 2B to be bent is twisted and bent with respect to the substrate 2A to be bent, the substrate 2B to be bent has a force pushed in the direction toward the bending groove 5 indicated by an arrow S in FIG. Works. Due to the action of the force generated when the substrate 2B is twisted and bent, the bent portion wiring circuit pattern 4C formed in the portion corresponding to the bent groove 5 is peeled off from the substrate 2 (actually the insulating layer 3). So as to rise. FIG. 4 shows a state where the bent portion wiring circuit pattern 4C is peeled off from the substrate 2 and floated. In the bent portion wiring circuit pattern 4 </ b> C that has been peeled off from the substrate 2, no cut portion is seen.

  As the angle θ formed by the bent portion wiring circuit pattern 4C with respect to the bending line 6 is smaller than 90 degrees, the bent portion wiring circuit pattern 4C is more easily peeled from the substrate 2 and is not cut. For this reason, in the bent portion wiring circuit pattern 4C, the copper foil is surely electrically connected, so that the conduction state of the first wiring circuit pattern 4A and the second wiring circuit pattern 4B is ensured.

  According to the wired circuit board 1 of the present embodiment configured in this way, even if the wiring width of the bent portion wiring circuit pattern 4C is narrow, it is not cut and rises like a mountain, peels off and floats. The conduction state between the first wiring circuit pattern 4A and the second wiring circuit pattern 4B can be reliably ensured.

  Further, according to the wired circuit board 1 of the present embodiment, even if the thickness of the substrate 2 that is a rigid conductive metal substrate is increased instead of the flexible substrate, the bent portion wiring circuit pattern 4C is increased. It is possible to prevent the cut portion from being generated, and the bent wiring circuit pattern 4C can be lifted from the substrate 2.

  As shown in FIG. 5, the LED 7 is mounted on the printed circuit board 1 that is used by being bent in this manner. An LED mounting hole 8 for mounting the LED 7 is formed in the substrate 2 so as to penetrate the plate thickness. The LED mounting holes 8 are respectively formed in the substrate 2A on the side to be bent and the substrate 2B on the side to be bent. On the insulating layer 3 formed on the substrate 2, two wiring layers 4 connected to both electrode terminals 9 and 9 of the LED 7 are formed in the vicinity of both side edges of the long side of the substrate 2. In the wiring layer 4, the bent portion wiring circuit pattern 4C is lifted from the substrate 2 as shown in FIG.

  The electrode terminals 9 and 9 of the LED 7 and the first wiring circuit pattern 4A and the second wiring circuit pattern 4B of the wiring layer 4 corresponding to the electrode terminals 9 and 9 are electrically connected by, for example, solder. By mounting the LED 7 on the substrate 2 in this way, a vehicular lamp using the LED 7 as a light source is configured. Since the vehicular lamp using the LED 7 as a light source is used as an alternative to a lamp using an incandescent bulb as the light source, the highly directional LED 7 is bent on the substrate 2 in order to obtain a light distribution close to the incandescent bulb's light distribution pattern. It is realized by using. For this reason, when the board 2 on which the LED 7 is mounted is bent, the wiring layer 2 is cut and the electric circuit is cut off. Therefore, by using the wiring circuit board 1 of the present embodiment, as an alternative to the incandescent bulb. The LED 7 can be used as a vehicular lamp.

  INDUSTRIAL APPLICABILITY The present invention can be used for a printed circuit board that is used by bending a substrate on which a wiring layer is formed.

DESCRIPTION OF SYMBOLS 1 ... Wiring circuit board 2 ... Board | substrate 3 ... Insulating layer 4 ... Wiring layer 4A ... 1st wiring circuit pattern 4B ... 2nd wiring circuit pattern 4C ... Bending part wiring circuit pattern 5 ... Bending groove 6 ... Bending line 7 ... LED
8 ... LED mounting hole 9 ... LED electrode terminal

Claims (3)

In a printed circuit board in which a wiring layer is formed as a predetermined pattern on an insulating layer formed on one surface of the substrate, and the substrate is bent and used,
A bending groove for bending the substrate is formed on the other surface of the substrate, and the wiring circuit pattern of the bent portion of the wiring layer located on the line of the bending groove is formed with respect to the line of the bending groove. The wiring width both side edges are crossed diagonally,
When the substrate is bent in a U-shaped manner so that the both side edges of both substrates do not coincide with each other, the folded wiring with respect to the substrate to be folded with the folding groove as a folding line. A printed circuit board, wherein a circuit pattern is lifted from the board. The printed circuit board according to claim 1,
The printed circuit board, wherein the substrate is a conductive metal substrate.   A vehicle lamp comprising an LED mounted on the wired circuit board according to claim 1 and an electrode terminal of the LED connected to the wiring layer.

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