JPH09275251A - Printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen a printed board in weight by a method wherein a large number of weight reduction holes are regularly provided in a conductor pattern which spreads wide. SOLUTION: A conductor pattern 82 which spreads over nearly all the surface of a printed wiring board 81, foot patterns 85 for connecting lead wires, and checkered patterns 86 which are regularly arranged are formed. In each checker of the checkered pattern 86, a trapezoidal weight reduction hole which is provided on each side of a first slant pattern 27 that is coincident with the diagonal line of each checker of the checkered pattern 86, and a right-angled triangular weight reduction hole which is demarcated with a second slant pattern 88 and each checker of the checkered pattern 86a and provided on each side of the trapezoidal weight reduction hole are regularly and symmetrically provided. The trapezoidal weight reduction hole and the right-angled triangular weight reduction hole provided in each checker of the checkered pattern 86 are combined so as to form a polygon. Weight reduction holes regularly arranged on a certain layer are made to deviate relatively in position from other weight reduction holes arranged on the other layer so as to stop a leakage electromagnetic waves from penetrating, whereby a printed wiring board can be improved in electromagnetic shielding effect.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a printed wiring board. In portable wireless communication devices, mobile phones, portable information processing devices, information communication devices, etc., miniaturization, high density, and thinning are being promoted, but the reduction in weight also includes structural members and parts. Is the same.

Also in printed wiring boards, which are circuit boards, optimization and thinning of the insulating layer and optimization and thinning of the thickness of the conductor layer are being studied, but such reduction in weight is not possible. Almost at the limit.

For example, in a current portable telephone, a printed wiring board occupies 30% of the total weight of electric parts except the battery part. This printed wiring board has 6
It has a layered structure, and the conductor (Cu) of the printed wiring board is 60% of the weight of the printed wiring board. Therefore, if this conductor can be effectively reduced within a range where it does not have an electrical effect, it will greatly contribute to weight reduction. Therefore, it is not easy to simply reduce the thickness of the conductor because it is limited as described above.

FIG. 22 shows the upper and lower double-sided layers and the middle four layers.
FIG. 2 is a plan view of a main part of a multilayer printed wiring board 10 including conductor layers, showing each layer in a separated state and seen from the top.

For the conductor layer, a conductor (Cu) foil is attached to the surface of an insulating substrate obtained by impregnating a cloth made of glass fibers with epoxy resin, a circuit pattern is formed by etching, and Cu plating is applied if necessary. Circuit board,
It is a so-called multi-layered printed wiring board made of a glass / epoxy substrate in which a prepreg made of an epoxy resin is interposed to form insulation and adhesion between layers to form a laminate by heat compression. Further, the circuit connection of the conductor layers between the respective layers is performed by a through hole for connecting the layers or a conductor through hole formed by a through hole only in a predetermined layer.

The conductor layers are arranged in order from the upper surface in the drawing as the first layer 11,
The second layer 12, the third layer 13, the fourth layer 14, the fifth layer 15, and the sixth layer 16, for example, the first layer 11 side is a high frequency circuit including a radio frequency, and the sixth layer 16 side is a telephone function. Circuit,
It is assumed that the second layer 12 and the fifth layer 15 are power supply circuits, and the third layer 13 and the fourth layer 14 are ground circuits. It should be noted that the respective circuit patterns are not shown in the drawing, and the reference numeral 18 is a mounting hole.

[0007]

2. Description of the Related Art A conventional printed wiring board 20 corresponding to the structure shown in FIG. 22 is shown in FIG. 23 as an enlarged view of a first layer 21 to a third layer 23, and a fourth layer 24 to a sixth layer 26.
24 is an enlarged view of FIG. In each of these figures, a circuit pattern of a typical conductor layer is shown.
The reference numerals 21 to 26 correspond to the reference numerals 11 to 16 in FIG.
These are the corresponding parts.

Referring to the first layer 21 on the surface, a frame-shaped ground conductor pattern 27 having a width having a relatively wide circumference is also provided.
(The conductor pattern having a spread is shown in the shaded area, but the same is true for other locations, as well as the locations shown below), and conductor through holes for ground connection are formed at small intervals. 28 is provided.

On the inner side, a QFP type IC mounting lead connection foot pattern 29 is formed in parallel and formed in a frame shape, and a square ground conductor pattern 31 is formed in the center thereof. Is also provided with a large number of conductor through holes for ground connection.

In addition, a grounding conductor pattern and a grounding conductor through hole, which are spread out at important points, and a power source conductor pattern and a power source connecting conductor through hole are formed.

The lead connection foot patterns 29 are connected to the linear circuit connection patterns 32, the ground connection conductor through holes, the power supply connection conductor through holes, and the like, respectively.

Other large and small rectangular conductor patterns 33
Are conductor patterns for mounting SMDs (Surface Mounted Components), each of which is connected to a main circuit by a linear circuit connecting conductor pattern or a conductor through hole.

The second layer 22, which is the second intermediate layer, is a (solid) power supply conductor pattern 35 having a spread, and is not connected to the power supply conductor pattern 35 in the periphery and in the main part but is insulated in a ring shape. The ground connection conductor through hole 36 and the power supply connection conductor through hole 37 connected to the first layer 21 are formed.

A third layer 23, which is a third intermediate layer, is a (solid) ground conductor pattern 41 having a spread, and a conductor through for ground connection connected to the ground conductor pattern 41 is provided around and around the ground conductor pattern 41. A hole 42, a power supply conductor through hole 43 connected to the power supply conductor pattern 35 of the second layer 22 and insulated in a ring shape, and the first layer 2
A linear independent circuit connecting pattern 44 for bypass-connecting one circuit pattern is formed so as to be connected by the circuit connecting conductor through holes at both ends.

Referring to FIG. 24, the fourth intermediate layer, the fourth
The layer 24 is a ground conductor pattern 5 having a spread (solid).
5, and the ground connection conductor through hole 56 connected to the ground conductor pattern 55 is provided around and around the main part.
And a power supply connection conductor through hole 57 which is connected to the power supply conductor pattern of the fifth layer 25 and is insulated in a ring shape.

The fifth layer 25, which is the fifth intermediate layer, is a wide (solid) power supply conductor pattern 61, and is not connected to the power supply conductor pattern 61 in the periphery and in the main part, but is insulated in a ring shape. The ground connection conductor through hole 62 and the power supply connection conductor through hole 63 connected to the sixth layer 26 are formed.

On the lower surface of the sixth layer 26, a frame-shaped ground conductor pattern 65 is formed with a width relatively wide in the periphery, and ground connection conductor through holes 66 are provided at small intervals. A rectangular circuit configuration conductor pattern 67, a linear circuit connection conductor pattern 68, a power source connection conductor through hole 69, and other circuit patterns (not shown) are formed on the inner side.

Around the first layer 21 to the sixth layer 26,
Through-holes 2 for connecting ground conductors formed in rows
8, 36, 42, 56, 62 and 66 are all connected to the same potential as the ground as through-holes, and because they are small intervals, they prevent the leakage of electromagnetic waves from the internal circuit and shield them. It works.

Other conductor through holes for ground connection,
The conductor through-holes for power supply connection, the conductor through-holes for circuit connection, etc. are also those through which the required conductor patterns between layers are appropriately connected.

In FIG. 25, a circuit conductor pattern formed on an appropriate layer of the printed wiring board 20, for example, the first layer 21, is a linear first conductor pattern 71, a band-shaped second conductor pattern 72, and a spread. A third conductive pattern 73 having a width of 4 and a similar fourth pattern 74 are formed.
These are set in a signal line pattern, a power line pattern, a ground conductor pattern, and the like.

As shown in the drawing, the second conductor pattern 72, the third conductor pattern 73, and the fourth conductor pattern 74 have a wide or narrow change in width in the extending direction due to various factors. Is formed.

[0022]

SUMMARY OF THE INVENTION As described above,
The printed wiring board is formed by complexly combining conductor patterns of various shapes. Regarding the shape thereof, there are various shapes such as a narrow conductor pattern, a wide conductor pattern, and a conductor pattern which is a combination thereof.

Since such a shape is required to satisfy the electrical characteristics, it is set as such. However, a pattern portion having a wide area including a wide pattern having a wide area is included. The existence of the conductor is a conductor, but the weight of the Cu foil layer, the Cu plating layer, and the like is considerable, and if it can be reduced, further weight reduction measures can be obtained.

However, as described above, reducing the thickness, narrowing the width, etc. have already been technically studied up to the limit state, and since it has been implemented, further The feasibility of relying on such a method is hardly hopeful.

In view of the above problems, it is an object of the present invention to further reduce the weight of a printed wiring board.

[0026]

The first means is to provide a large number of regular weight reducing holes in a conductor pattern having an expanse in order to solve the above problems. It is a printed wiring board.

Since providing a large number of regular weight reducing holes results in a fine mesh-shaped conductor pattern, the substantial electrical area is not reduced, and the electrical characteristics are maintained and the printed wiring is maintained. The weight of the board will be reduced. If necessary, it is possible to provide a conductor through hole in the weight reducing hole without being connected to the conductor pattern.

The second means is a printed wiring board in which the weight reducing holes of the first means are polygonal. The regular polygon makes it possible to form a fine mesh-shaped conductor pattern formed between adjacent sides of the polygon, and an optimum conductor width can be arbitrarily set.

The third means is a printed wiring board in which the weight reducing holes of the second means are hexagonal. By making the regular polygonal shape a hexagonal shape, it is possible to minimize the entire width of the fine mesh-shaped conductor pattern formed between the adjacent sides of the hexagonal shape.

The fourth means is a printed wiring board in which the weight reducing holes of the first means are circular. The regular circular shape makes it possible to form a fine mesh-shaped conductor pattern by appropriately selecting and setting from a perfect circle, an ellipse, an ellipse, etc., and the optimum conductor layer can be arbitrarily set. You can

The fifth means is a printed wiring board in which the weight reducing holes of the first means have a diagonal pattern passing through diagonal lines of the grid pattern. A regular fine mesh can be formed by combining with a diagonal pattern of the grid-like pattern, and good electrical characteristics can be maintained.

A sixth means is a printed wiring board in which a weight reducing hole having a shape along the outer shape of the conductor pattern is provided in a wide conductor pattern portion. The weight of the printed wiring board can be reduced by providing the weight reducing hole having a shape along the outer shape in the wide conductor pattern portion in a range that does not significantly affect the electrical characteristics. If necessary, it is possible to provide a conductor through hole that is not connected to the conductor pattern in the weight reducing hole.

In the seventh means, a layer in which a conductor pattern to which the first means to the sixth means is applied is formed is a multilayer, and a weight reducing hole is provided in at least one conductor pattern of the printed wiring board. Is.

Since the printed wiring board is a multi-layered printed wiring board, the more layers are applied, the greater the amount of weight reduction can be. Eighth means is a printed wiring board formed by laminating a first conductor layer and a second conductor layer in which a large number of regular weight reducing holes are provided in a conductor pattern having a spread,
In the printed wiring board, the positions of the weight reducing holes of the first conductor layer and the second conductor layer are relatively displaced.

By offsetting the positions of the regularly arranged weight reducing holes between the layers, the weight reducing holes are different from each other,
Since the weight reducing holes of the other layers are covered with the conductors adjacent to each other, the shielding action and the effect of blocking the transmission of the leaked electromagnetic waves are remarkable despite the existence of the weight reducing holes.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the printed wiring board of the present invention will be specifically described in detail with reference to the drawings by the embodiments based on the gist of the construction. It is to be noted that like parts are denoted by like reference numerals throughout the drawings.

FIG. 1 is a plan view of a first embodiment of a printed wiring board according to the present invention, showing an evaluation model of a conductor pattern having a weight reducing hole and having a spread. The external dimensions of the printed wiring board 81 are the actual size, for example,
The width is set to about 45 mm and the length is set to about 100 mm. That is, the conductor pattern 82 having a spread is formed on almost the entire surface of the printed wiring board 81, and the QFP type IC mounting area 83 is provided at two locations inside thereof.

A wide frame-shaped conductor pattern 84 is provided in the center of the IC mounting area 83, and foot patterns 85 for connecting lead wires are arranged in parallel on four sides of the frame-shaped conductor pattern 84 to form a frame shape. ing.

The widened conductor pattern 82 and the frame-shaped conductor pattern 84 are both square-shaped grid patterns 86 in the vertical and horizontal directions in the drawing, and a first diagonal line pattern passing through diagonal lines of the grid-shaped patterns 86. 87 and a second diagonal line pattern 88 that is parallel to the first diagonal line pattern 87 and crosses the middle of each side of the grid-shaped pattern 86, and the first weight reduction pattern 89 is regular. Is formed in.

Conductor pattern 8 having such a spread
Reference numeral 2 denotes an area corresponding to the power supply conductor pattern 35, the ground conductor pattern 41, or the like in the conventional technique as shown in FIG. 23, in which the weight reduction amount is measured and the shield function for electrical electromagnetic shielding is measured. Etc. are considered.

By the way, the size of the grid is 2.5 m on each side.
By setting m, the first diagonal pattern 8 passing through a diagonal line is formed in each of these one grid-like patterns 86.
7, trapezoidal weight reduction holes and right-angled triangular weight reduction holes formed by the second diagonal pattern 88 and the grid pattern 86 on both sides of the trapezoidal weight reduction holes are formed symmetrically and regularly. It These grid-shaped pattern 86, trapezoidal weight reduction hole, and right-angled triangular weight reduction hole are all combinations of polygons.

A hole having a large diameter is a hole 91 for attachment to a housing or the like, and a hole having a small diameter is a conductor through hole 92. FIG. 2 is a plan view of a second embodiment of the printed wiring board of the present invention, showing an evaluation model of a conductor pattern having a weight reduction hole and having a spread. The external dimensions of the printed wiring board 93 are the actual size, for example, the width is about 4
The length is set to 5 mm and the length is about 100 mm.

A conductor pattern 94 having a spread is formed over the entire area of the printed wiring board 93, and the conductor pattern 94 is configured as a second weight reduction pattern 95. That is, the second weight reduction pattern 95 has a large number of hexagonal weight reduction holes 97 which are regularly formed adjacent to each other in a certain direction.

That is, it is regularly arranged in a row in the width direction and in a staggered arrangement in the length direction. In the drawing, the intermediate portion of the formation area of the turtle shell weight reduction hole 97 is omitted in the drawing. The tortoiseshell-shaped weight reducing hole 97 is a polygon, that is, a regular hexagon.

The conductor pattern 94 having such a wide area is
As shown in FIG. 23, in a region corresponding to the power supply conductor pattern 35 or the ground conductor pattern 41 in the related art, the measurement of the weight reduction amount and the measurement of the shield function of electric electromagnetic shielding are considered. It is what is done.

The conductor pattern width between the adjoining weight-reducing holes 97 of the hexagonal shape is kept at a minimum, for example, 0.3 mm, the diameter of the regular hexagon inscribed circle is 1.47 mm, and the diameter of the circumscribed circle. Is about 1.7 mm, and is configured as a fine mesh as a whole.

In the figure, in the region where the weight reducing hole 97 is formed, a portion 98 where the weight reducing hole 97 is not continuous is a portion where a conductor through hole connected to the conductor pattern 94 is formed in a later step. Also in this embodiment, the hole having a large diameter is the hole 91 for attachment to the housing or the like.

FIG. 3 shows an enlarged view of the different conductor patterns 94 of the printed wiring board 93 of the embodiment shown in FIG. In this embodiment, diagonal lines are shown in the formation area of the conductor pattern 94 having a large area, and the hexagonal weight reducing hole 97 extends over almost the entire surface of the hexagonal weight reducing hole 97. Inside, conductor pattern 9
It is shown that a conductor through hole 99 which is in a non-connection state with No. 4 is provided. The diameter of the conductor through hole 99 is about 0.3 mm.

An enlarged view of the first to third layers of the printed wiring board of the present invention, which corresponds to the structure of the printed wiring board shown in FIG. 22, is shown in FIG. 4, and the fourth to sixth layers are shown. An enlarged view is shown in FIG. These configurations can correspond to those in FIG.

The printed wiring board 100 of the present invention comprises the first layer 1
01, the second layer 102, the third layer 103, the fourth layer 104, the fifth layer 105, and the sixth layer 106, the circuit patterns of typical conductor layers are shown in these figures for easy understanding. In order to do so, it is shown so as to correspond to the prior art of FIGS.

Therefore, the reference numerals 101 to 106 seem to correspond to the reference numerals 11 to 16 in FIG. 22, respectively.
Further, according to the present embodiment, the conductor patterns having the spread, which are applied to the evaluation models shown in FIGS. 1, 2, and 3, are effectively combined and applied to the conductor pattern part having the spread. It is in.

Referring to the first layer 101 on the surface, a frame-shaped ground conductor pattern 11 having a width relatively wide in the periphery is provided.
1 are formed, and conductor through holes for ground connection 1 at small intervals
12 are provided.

On the inner side, a QFP type IC mounting lead connection foot pattern 85 is formed in parallel and is formed in a frame shape, and a square ground conductor pattern 84 is formed in the center thereof, and the ground conductor pattern 84 is formed. A large number of conductor through holes for ground connection are provided therein.

In addition, a grounding conductor pattern and a grounding conductor through hole which are spread out at important points, a power supply conductor pattern and a power supply connecting conductor through hole are formed.

The lead connection foot pattern 85 is connected to the linear circuit connection pattern 113, the ground connection conductor through hole, the power supply connection conductor through hole, and the like.

Other large and small rectangular conductor patterns 11
Reference numeral 4 denotes conductor patterns for mounting SMDs (surface mounted components), each of which is connected to a main circuit by a linear circuit connection conductor pattern or a conductor through hole.

A ground conductor pattern 111 having a spread,
84 and the like have a first weight reduction pattern 89 which is composed of a square-shaped grid pattern 86 in the vertical and horizontal directions in the drawing and a first diagonal line pattern 87 extending diagonally from the grid-shaped pattern 86. Has been formed.

This first weight reduction pattern 89 is shown in FIG.
The description is basically the same as that described with reference to FIG.
Right and left triangular weight reducing holes formed with the grid pattern 86 are formed on both sides of the diagonal pattern 87 of FIG. These grid-like patterns 86 and right-angled triangular weight reducing holes are all combinations of polygons.

The second layer 102, which is the second intermediate layer, is a (solid) power supply conductor pattern 115 having a range and a spread shown by hatching, and this power supply conductor pattern 1
A second weight reduction pattern 95 in which hexagonal weight reduction holes 97 are regularly formed is applied to 15.

The conductor through hole 11 for ground connection penetrating through the center of the hexagonal weight reducing hole 97 is formed on the periphery and main parts so as not to be connected to the power source conductor pattern 115.
6 and a power supply connection conductor through hole 117 connected to the power supply conductor pattern 115 in the middle of the hexagonal weight reduction hole 97 and connected to the first layer 101.

The size and arrangement of the hexagonal shaped weight reducing holes 97 are the same as described with reference to FIGS. 2 and 3. The third layer 103, which is the third intermediate layer, is a (solid) ground conductor pattern 121 having a range and a spread indicated by hatching, and the ground conductor pattern 121 has a hexagonal shaped weight reducing hole 97. A second weight reduction pattern 95 is applied, in which are regularly formed.

Around the conductor and the main portion, the conductor through hole 1 for ground connection connected to the ground conductor pattern 121 is formed.
23 and the power supply conductor pattern 102 of the second layer so as not to be connected to the conductor through hole 123 for ground connection.
And a conductor independent through hole 124 for power supply that penetrates through the center of the hexagonal weight reduction hole 97 and a linear independent circuit connection conductor pattern 125 that bypass-connects the circuit pattern of the first layer 101. , Are formed so as to be connected by circuit through conductor through holes at both ends.

Referring to FIG. 5, fourth layer 104, which is the fourth intermediate layer, is a (solid) ground conductor pattern 126 having a range and a spread shown by hatching. A second weight reduction pattern 95 in which turtle shell weight reduction holes 97 are regularly formed is applied.

A conductor through hole 1 for ground connection connected to the ground conductor pattern 126 is provided around and around the main portion.
27 and connected to the power supply conductor pattern of the fifth layer 105,
A power source connecting conductor through hole 128 is formed through the center of the hexagonal weight reducing hole 97.

The fifth layer 105, which is the fifth intermediate layer, is a (solid) power supply conductor pattern 131 having a range and a spread shown by hatching.
A second weight reduction pattern 95 in which hexagonal weight reduction holes 97 are regularly formed is applied to 31.

In the periphery and in the main part, a grounding conductor through hole 132 which is not connected to the power source conductor pattern 131 but penetrates the center of the hexagonal shaped weight reducing hole 97, and a power source which is connected to the sixth layer 106. Connection conductor through hole 1
33 and are formed.

On the lower surface of the sixth layer 106, a frame-shaped ground conductor pattern 135 is formed with a width relatively wide in the periphery, and ground connection conductor through holes 136 are provided at small intervals. On the inner side, a rectangular circuit configuration conductor pattern 137, a linear circuit connection conductor pattern 138, a power supply connection conductor through hole 139, and other circuit patterns (not shown) are formed.

The grounding conductor pattern 135 and the like having a spread are all square-shaped square-shaped patterns 86 in the vertical and horizontal directions in the drawing.
And a first diagonal line pattern 87 extending diagonally from the mesh pattern 86, a first weight reduction pattern 89 is regularly formed.

This first weight reduction pattern 89 is shown in FIG.
The description is basically the same as that described with reference to FIG.
Right and left triangular weight reducing holes formed with the grid pattern 86 are formed on both sides of the diagonal pattern 87 of FIG. These grid-like patterns 86 and right-angled triangular weight reducing holes are all combinations of polygons.

Grounding conductor through holes 112, 116, 123, 127, 132, 136 formed in rows around the first layer 101 to the sixth layer 106 are
When they are all laminated as a multilayer printed wiring board, they are connected to the same potential as ground as through-holes, and because they are small intervals, they prevent the leakage of electromagnetic waves from internal circuits and function as a shield. To do.

Other conductor through holes for ground connection,
The conductor through-holes for power supply connection, the conductor through-holes for circuit connection, etc. are also those through which the required conductor patterns between layers are appropriately connected.

The first weight reduction pattern 89 and the second weight reduction pattern 95 are not limited to those in this embodiment, and can be appropriately replaced or combined and applied.

As described above, by applying the weight reducing pattern to the conductor pattern having the spread, the weight of the printed wiring board can be reduced by about 30% as compared with the conventional one, and the electric characteristics are reduced. , Data that it does not have a big influence was also obtained and proved.

FIG. 6 is a partially enlarged view showing a first embodiment of the second weight reduction pattern applied to the printed wiring board of the present invention. The weight reduction pattern 95-1 is a hexagonal shape having regular hexagons (polygons) at the space P1 in the vertical and horizontal directions in the region where the conductor pattern 94 having a spread with diagonal lines is formed and in the middle thereof. Weight reduction hole 9
Many 7 are provided with a fixed direction.

To provide the conductor through hole 99 in a state where it is not electrically connected to the conductor pattern 94,
As shown in the figure, a small-diameter through hole can be provided at the center of the hexagonal shaped weight reducing hole 97.

The size of the hexagonal weight reducing hole 97, the conductor width between adjacent holes, the diameter of the conductor through hole 99, etc. are set as described above. FIG. 7 is a partially enlarged view showing a second embodiment of the second weight reduction pattern applied to the printed wiring board of the present invention. Weight reduction pattern 95-2
Is a conductor pattern 94 having a spread with diagonal lines.
In the area where is formed, a plurality of hexagonal hexagonal (polygonal) hexagonal weight reducing holes 97 are provided in the vertical and horizontal directions at intervals P2 and P3, respectively, and in the middle thereof. The relationship between P2 and P3 is (2 × P2 = P3)
It is.

According to this embodiment, the width of the conductor 94 between the adjoining weight reducing holes 97 can be narrowed uniformly, so that the remaining rate of the conductor 94 can be reduced and the weight can be further reduced. You can

In order to provide the conductor through-hole 141 in a state of being electrically connected to the conductor pattern 94, as shown in the figure, a portion where the hexagonal shaped weight reducing hole 97 is not provided is formed. It can be formed by providing through holes. This also applies to the embodiment shown in FIG.

The conductor pattern 94 can be formed by providing a through hole at the center of the hexagonal shaped weight reducing hole 97 in order to provide a conductor through hole without being electrically connected.

The size of the tortoiseshell-shaped weight reducing holes 97, the conductor width between adjacent holes, the diameter of the conductor through hole, and the like are set as described above. FIG. 8 is a partially enlarged view showing a third embodiment of the second weight reduction pattern applied to the printed wiring board of the present invention. The weight reduction pattern 95-3 is
In the region where the conductor pattern 94 having a spread with diagonal lines is formed, the intervals P4 and P5 in the vertical and horizontal directions, and the hexagonal hexagonal (polygonal) hexagonal weight reducing holes 97 in the middle thereof are formed. However, a large number are provided with a fixed direction. The relationship between P4 and P5 is that the adjacent weight reducing holes 9
The width between the sides of the conductor 7 of No. 7 is set to a constant value or a relationship that is approximated to a constant value.

According to the present embodiment, the remaining rate of the conductor 94 can be further reduced, so that the weight can be remarkably reduced. In order to provide the conductor through hole 141 in a state of being electrically connected to the conductor pattern 94, as shown in the figure, a portion without the hexagonal weight reducing hole 97 is formed, and a through hole is provided there. It can be provided and formed.

The conductor pattern 94 can be formed by providing a through hole at the center of the hexagonal weight reducing hole 97 in order to provide a conductor through hole without being electrically connected.

The size of the hexagonal weight reducing hole 97, the width of the conductor between adjacent holes, the diameter of the conductor through hole, and the like are set as described above. FIG. 9 is a partially enlarged view showing the first embodiment of the third weight reduction pattern applied to the printed wiring board of the present invention. The weight reduction pattern 145 is a quadrangle weight reduction hole formed by a regular quadrangle (polygon) in an area where the conductor pattern 94 having a spread with hatching is formed, and an interval P1 in the vertical and horizontal directions and an intermediate portion thereof. A large number of 146 are provided so that the diagonal direction is the vertical and horizontal directions and the directions are constant.

According to this embodiment, the width of the conductor 94 between the sides of the adjacent weight reducing holes 146 can be set to be constant. By giving an appropriate curved surface (R surface) to the corner of the square weight reducing hole 146, the diameter ratio of the circumscribed circle and the inscribed circle can be reduced.

To provide the conductor through hole 99 in a state where it is not electrically connected to the conductor pattern 94,
As shown in the figure, a small-diameter through hole can be provided in the center of the square weight reducing hole 146 to form the weight reducing hole 146.

In order to provide a conductor through hole in a state of being electrically connected to the conductor pattern 94, a portion where the square weight reducing hole 146 is not provided is formed and a through hole is provided therein. it can.

The size of the square weight reducing hole 146, the conductor width between adjacent ones, the diameter of the conductor through hole, and the like are set to be the same as or close to the above-mentioned hexagonal weight reducing hole 97. FIG. 10 shows the first applied to the printed wiring board of the present invention.
1st Embodiment of the weight reduction pattern of this is shown in a partially enlarged view. The weight reduction pattern 89-1 is a square-shaped grid pattern 86 at intervals P1 in the vertical and horizontal directions in a region where the conductor pattern 82 having a spread with diagonal lines is formed.
And a first diagonal line pattern 87 passing through a diagonal line of the grid-shaped pattern 86, and a second diagonal line pattern which is parallel to the first diagonal line pattern 87 and crosses the middle of each side of the grid-shaped pattern 86. A first weight reduction pattern 89-1 composed of 88 and 88 is regularly formed.

The first weight reduction pattern 89-1 has a grid size of 2.5 mm on one side and a grid pattern 86,
The conductor width of each of the first diagonal line pattern 87 and the second diagonal line pattern 88 is 0.3 mm.

In addition, in one grid pattern 86,
Each of them has a trapezoidal weight reduction hole 151 on both sides of the first diagonal line pattern 87 and second diagonal line patterns 88 on both sides thereof.
The weight reducing holes 152 of right-angled triangle formed by the square pattern 86 and the square pattern 86 are formed symmetrically and regularly.

The grid-like pattern 86, the trapezoidal weight reducing hole 151, and the right triangle weight reducing hole 152 are all a combination of polygons. FIG.
Second, a partially enlarged view of a second embodiment of the first weight reduction pattern applied to the printed wiring board of the present invention is shown. FIG. 3A is a plan view, and FIG. 3B is a side sectional view showing only one layer. The weight reduction pattern 89-2 is formed in an area where the conductor pattern 82 having a spread with diagonal lines is formed.
A rectangular grid-like pattern 86 at intervals P1 in the vertical and horizontal directions, a first diagonal line pattern 87 extending diagonally from the grid-like pattern 86, and each side of the grid-like pattern 86 parallel to the first diagonal line pattern 87. A first weight reduction pattern 89-2 is formed regularly, which is composed of a second diagonal line pattern 88 that crosses the middle of the pattern.

The above construction is similar to that shown in FIG. 10, but the directions of the first diagonal line pattern 87 and the second diagonal line pattern 88 differ by 90 °. Further, the conductor through hole 155 electrically connected to the grid pattern 86, the first diagonal line pattern 87, and the second diagonal line pattern 88 is appropriately formed at an appropriate position and the enlarged pattern 156 surrounding the conductor through hole 155. Formed with.

Further, the through conductor through hole 157 for other interlayer connection which is not electrically connected to the grid pattern 86, the first diagonal line pattern 87, and the second diagonal line pattern 88.
Are formed by providing the pattern conductor breaking portion 158 around the conductor through hole 157.

The weight reduction pattern 89-1 in FIG. 10 is
The first slanted line pattern 87 and the second slanted line pattern 88 are made to have different inclination directions so that the weight reduction patterns 89-1 and 89-2 are combined between the adjacent layers, and thus the first slanted line in plan view. The pattern 87 and the second diagonal line pattern 88 intersect with each other, so that transmission of leaked electromagnetic waves can be largely blocked.

FIG. 12 is a partially enlarged view showing a third embodiment of the first weight reduction pattern applied to the printed wiring board of the present invention. The weight reduction pattern 89-3 is a rectangular grid pattern 86 at intervals P1 in the vertical and horizontal directions in a region where the conductor pattern 82 having a spread with diagonal lines is formed, and both diagonal lines of the grid pattern 86. By forming the two first diagonal patterns 87 passing through, the two first diagonal lines 87 intersect at the center of the grid pattern 86. With this configuration, the first weight reduction pattern 89-3 is regularly formed.

In each one grid-shaped pattern 86, four right-angled triangles each composed of each side of the grid-shaped pattern 86 and two sides of the two first diagonal line patterns 87 are formed. The weight reduction holes 161 are formed symmetrically and regularly. All of these grid-shaped patterns 86 and right-angled triangular weight reduction holes 161 are made up of a combination of polygons.

According to this weight reduction pattern 89-3,
Two first diagonal line patterns 87 are provided in the grid pattern 86.
By forming the intersecting portion by, the effect of preventing the transmission of leaked electromagnetic waves becomes even greater. The conductor through holes can be formed in the same manner as in FIG.

FIG. 13 is a partially enlarged view showing a first embodiment of the fourth weight reduction pattern applied to the printed wiring board of the present invention. The fourth weight reduction pattern 165 has a hexagonal conductor pattern 166 in which regular hexagons having a space P1 are continuously formed in a region where the conductor pattern 82 having a spread with diagonal lines is formed, and a hexagonal pattern. The conductor pattern 166 is composed of three diagonal line patterns 167 passing through respective diagonal lines, and is regularly formed.

Therefore, the hexagonal conductor pattern 166 is provided.
Three diagonal patterns 167 are crossed in the central part of the inside, and in one hexagonal conductor pattern 166,
Six equilateral triangular weight reducing holes 168 each having a hexagonal conductor pattern 166 as one side and each adjacent diagonal pattern as one side are formed symmetrically and regularly. The tortoise shell-shaped conductor pattern 166 and the equilateral triangular weight reduction hole 168 are all a combination of polygons.

The fourth weight reducing pattern 165 is adjacent to each side of the equilateral triangular weight reducing hole 168 and is symmetrical with respect to each side through the conductor width.
It can also be considered that 8 is formed continuously in a regular manner.

The interval P1 is about 5.0 mm and the conductor width is 0.
It is about 3 mm, and since the respective oblique line patterns intersect at the apexes of the equilateral triangle, it is difficult for leaked electromagnetic waves to pass therethrough, the remaining rate of the conductor is small, and the weight reduction effect is large.

FIG. 14 is a partially enlarged view showing a first embodiment of the fifth weight reduction pattern applied to the printed wiring board of the present invention. In the fifth weight reduction pattern 171, in the region where the conductor pattern 172 having the spread with diagonal lines is formed, the interval P1 in the vertical and horizontal directions and the circular weight reduction holes 173 are regularly formed in the middle thereof. Many are provided.

According to this embodiment, the conductor widths between the adjacent weight reducing holes 173 are spread only on the apex of a circular arc, and both sides thereof are widened, so that the amount of leaked electromagnetic waves can be suppressed. That is, the shielding effect is large.

In order to provide the conductor through hole 174 in a state where it is not electrically connected to the conductor pattern 171, a subtotal through hole is provided at the center of the circular weight reducing hole 173 as shown in the drawing. be able to.

In order to provide a conductor through hole in a state of being electrically connected to the conductor pattern 171, a circular weight reducing hole 173 is not provided and a through hole is provided therein. it can.

The size of the circular weight reducing hole 173, the conductor width between adjacent ones, the diameter of the conductor through hole, and the like are set to be the same as or similar to those of the hexagonal weight reducing hole 97 described above.
FIG. 15 is a plan view of a sixth embodiment of a sixth weight reduction pattern applied to the printed wiring board according to the present invention, which is an enlarged view of a main part. The sixth weight reducing pattern 181 is opposed to the lead wire pattern 183 extending from the rectangular lead wire connecting foot patterns 182 arranged in parallel, and the SMD arranged opposite to the lead wire pattern 183.
(Surface mount component) A lead wire pattern 185 extending from a rectangular conductor pattern 184 for connection is shown.
These foot patterns 182 and rectangular conductor patterns 1
The electronic component 84 is mounted and soldered with electronic parts, for example, lead wires of a QFP type IC device and electrode terminals of a chip resistor. For good soldering, for example, Au plating is applied. .

For the reason described later, in order to limit the range of Au plating, solder resist is applied on the printed wiring board instead of the plating resist, and a solder resist film 186 is formed to cover the surface. At this time, window holes 187 are formed as shown in the drawing only at the portions necessary for soldering, so that the foot patterns 182 and the rectangular conductor patterns 184 can be seen on the surface, and Au plating can be applied here. To do. In this way, the pattern 182 with the oblique lines added
Plating is formed only on the 184 portion, the weight can be reduced, and the amount of Au used can be reduced accordingly.

FIG. 16 is an enlarged side sectional view of an essential part of one embodiment of a seventh weight reduction pattern applied to the printed wiring board of the present invention. This figure is an explanatory view of a method for forming the weight reduction pattern of the present invention, and shows a multilayer printed wiring board 100 in which six layers are laminated.

First layer 101, second layer 102, third layer 10
The third, fourth layer 104, fifth layer 105, and sixth layer 106 are patterned conductor layers, and an insulating layer is interposed between them.

After the above-mentioned layers 101 to 106 are aligned with each other and laminated and hardened, a through hole 191 is formed at a predetermined position. The diameter of this pilot hole 191 is, for example, 0.3 mm.
It is a degree.

On the surfaces of the first layer 101 and the sixth layer 106, for example, a solder resist film 192 is applied in place of the plating resist film, and the periphery of the pilot hole 191 is covered with the first layer 101 and the sixth layer 106.
The layer 106 is exposed like a ring. Also, the third layer 103
Only the inside of the lower hole 191 is looking around. First layer 10
1 and the ring-shaped portion 193 on the surface of the sixth layer 106 is 0.6
The diameter is set to about mm.

Referring to FIG. 17, the first layer 101 and the sixth layer
A state in which the Cu-plated layer 195 is formed by electrolytic plating after the electroless plating is applied to the ring-shaped portion 193 and the pilot hole 191 of the layer 106 is shown. This allows
Since the first layer 101, the third layer 103, and the sixth layer 106 are electrically connected, the conductor through hole 196 having a sufficient thickness can be obtained.

Since the other conductor pattern surfaces of the surfaces of the first layer 101 and the sixth layer 106 are covered with the solder resist film 192, Cu plating or the like is not formed, so that the weight of the printed wiring board 100 can be reduced. Can be planned.

FIG. 18 is a plan view showing an enlarged main part of an embodiment of an eighth weight reduction pattern applied to the printed wiring board according to the present invention. In the present embodiment, for ease of understanding, the second weight reduction pattern 95 shown in FIGS. 6, 7, and 8 will be representatively described and described. In addition,
As an example of the layers, the relationship between the nth layer and the (n + 1) th layer is set.

In the region of the n-th layer shown by the solid line where the conductor pattern 94 (n) having a spread with hatching is formed, the intervals of P2 and P3 in the vertical and horizontal directions, and the interval between them are equal to each other. A large number of hexagonal hexagonal weight reducing holes 97 (n) are provided in a constant direction. The relationship between P2 and P3 is (2 × P2 = P3).
This is the same as in FIG. 7. Therefore, the size of the tortoiseshell-shaped weight reducing hole 97, the conductor width between adjacent holes, etc. are as described above.

The n + 1-th layer is the same as the n-th layer with respect to the conductor pattern 94 (n + 1) having a spread, the weight reducing hole 97 (n + 1), etc., but as shown by the dotted line, it is in the X (horizontal) direction in the figure. At a position 1/2 of P2, that is, at a position that is exactly offset by a half pitch of P2, the n-th layer and the n-th layer.
The +1 layer weight reducing holes 97 are set to overlap each other.

By adopting such a configuration, the electromagnetic waves that try to pass through and leak through the weight reducing holes 97 work effectively so as to be shielded by the conductor portions of the adjacent borders of the conductor patterns of the weight reducing holes 97. The electromagnetic shield will be used.

By effectively selecting and positioning the residual width of the conductor pattern between the weight reducing holes 97 so as to cover the weight reducing holes 97 of the adjacent layers, a further shielding effect can be obtained.

In the embodiment of the present invention, the turtle shell-shaped weight reducing hole 9 is used.
It is arbitrary that the present invention is not limited to 7 and can be applied by being replaced with all the patterns formed by the other weight reducing holes described above.
Needless to say, it will be easily understood without explanation.

In FIG. 19, a circuit pattern formed on an appropriate layer of the printed wiring board 100, for example, the first layer 101, includes a linear first conductor pattern 201, a belt-shaped second conductor pattern 202, and a spread pattern. A third conductor pattern 203 having a width of 4 and a similar fourth conductor pattern 204 are formed. These are set as a signal line conductor pattern, a power line conductor pattern, a ground conductor pattern, and the like.

As shown in the drawing, the second conductor pattern 202, the third conductor pattern 203, and the fourth conductor pattern 204 change their width in a wide or narrow direction due to various electrical factors. It is formed to have.

In the second conductor pattern 202, a widened portion 211 is formed so as to follow the outer shape of the portion.
A weight reducing hole 213 having a shape whose width is equivalent to that of the narrow portion 212 is provided.

In the third conductor pattern 203, the width portions 215, 216, and 217 having a width are respectively formed along the outer shape of the width portions 215, 216, and 217 so that a weight reducing hole having a width necessary for forming a circuit is formed. 218, 219 and 221 are provided.

In the fourth conductor pattern 204, the width portions 222, 223 having a width are respectively formed so as to follow the outer shape of the portions, and the weight reducing holes 224 having a shape necessary to form a circuit, 225 is provided.

The weight of the printed wiring board is affected by providing the regular weight reducing holes in the width portion having the spread of the conductor pattern as described above and having the shape along the outer shape of the conductor pattern. The conductor pattern can be effectively reduced without affecting electrically.

FIG. 20 shows an electrical evaluation / measurement method by forming a weight-reducing conductor pattern in a conductor pattern region having a spread of the printed wiring board of the present invention. That is, the printed wiring board 101 is, for example, 2
The printed wiring board 10 is formed on the material substrate 231 formed by one sheet.
1, a conductor pattern 232 for electrical characteristic measurement is formed.

By connecting a measuring device to the conductor pattern for measurement and measuring the characteristic impedance in the range of 50Ω ± 7.5Ω by the TDR method, the degree of weight reduction of the conductor pattern and its influence can be measured.

FIG. 21 shows a printed wiring board 235 of the present invention.
Shown for shape. The printed wiring board 235 is formed with a positioning reference hole 236 for attachment at one end, and the other four attachment holes 237 and 238 are U-shaped opening holes that open at the end portions of the printed wiring board, thereby forming a circular shape. Since the base material and the conductor pattern of the printed wiring board can be reduced rather than the holes, the weight can be reduced.

According to the present invention, by combining the various means as described above, the weight of the printed wiring board itself can be reduced by a maximum of 30% as compared with the weight limit by the conventional means. It is possible.

[0129]

As described above in detail, according to the printed wiring board of the present invention, firstly, by providing a large number of regular weight-reducing holes in a conductor pattern having a wide area, a fine mesh conductor is provided. Since the pattern is formed, it is possible to reduce the weight of the printed wiring board while maintaining the electrical characteristics without substantially reducing the electrical area. The inside of the weight reducing hole may be used to provide a conductor through hole for connection between layers.

Second, by making the weight reducing holes polygonal, the parallel conductor width between the adjacent weight reducing holes can be arbitrarily set. Thirdly, by making the polygonal shape of the weight reducing holes into a hexagonal shape, it is possible to minimize the entire width of the fine mesh-shaped conductor pattern formed between adjacent hexagonal shapes.

Fourthly, by making the weight reducing holes circular so as to have a perfect circle, an ellipse, an ellipse, etc., a finer mesh pattern can be obtained. It is also possible to combine such various circular shapes, and it is possible to effectively reduce the weight and effectively prevent the transmission of electromagnetic waves.

Fifth, by making the weight reducing hole a combination pattern with a diagonal pattern of the grid-like pattern, the weight reduction of the printed wiring board is significantly improved and the transmission of electromagnetic waves is effectively prevented. You can

Sixth, by providing a weight reducing hole having a shape along the outer shape of the conductor pattern in the wide conductor pattern portion, the weight reducing amount can be increased without affecting the electrical characteristics. it can.

Seventh, applying the weight reducing means to the multilayer printed wiring board can increase the amount of weight reduction as a whole, so that the larger the number of layers, the more remarkable the effect.

Eighth, by shifting the positions of the weight reducing holes of the laminated printed wiring boards according to each other, there is a so-called covering effect of covering the opening portions of the weight reducing holes with the conductor pattern between the weight reducing holes. The effect and the effect of blocking the transmission of electromagnetic waves become remarkable.

As described above, according to the printed wiring board of the present invention, it is applied to various portable types, wireless communication devices, portable telephones, portable information processing devices, information communication devices, etc. The effect of contributing to weight reduction is extremely remarkable.

[Brief description of drawings]

FIG. 1 is a plan view of a first embodiment of a printed wiring board according to the present invention.

FIG. 2 is a plan view of a second embodiment of the printed wiring board according to the present invention.

FIG. 3 is an enlarged view of a main part of a conductor pattern layer different from FIG.

FIG. 4 is an enlarged plan view (No. 1) of essential parts of an embodiment of a printed wiring board according to the present invention.

FIG. 5 is an enlarged plan view (No. 2) of a main part of the embodiment of the printed wiring board according to the present invention.

FIG. 6 is a partial enlarged view (No. 1) of a second weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 7 is a partial enlarged view (part 2) of the second weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 8 is a partial enlarged view (part 3) of the second weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 9 is a partially enlarged view of a third weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 10 is a partial enlarged view (No. 1) of the first weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 11 is a partial enlarged view (part 2) of the first weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 12 is a partial enlarged view (No. 3) of the first weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 13 is a partial enlarged view of a fourth weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 14 is a partial enlarged view of a fifth weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 15 is a partial enlarged view of a sixth weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 16 is an enlarged side cross-sectional view (No. 1) of essential parts of a seventh weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 17 is an enlarged side sectional view (No. 2) of a main part of a seventh weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 18 is a partial enlarged view of an eighth weight reduction pattern applied to the printed wiring board of the present invention.

FIG. 19 is an enlarged view of a circuit pattern main part of the printed wiring board of the present invention.

FIG. 20 is a method for evaluating and measuring the printed wiring board of the present invention.

FIG. 21 is an embodiment of the shape of a printed wiring board of the present invention.

FIG. 22 is a plan view of an essential part of a multilayer printed wiring board.

FIG. 23 is an enlarged plan view (1) of a conventional main part of a multilayer printed wiring board.

FIG. 24 is an enlarged plan view (No. 2) of a related-art main part of a multilayer printed wiring board.

FIG. 25 is an enlarged view of a circuit pattern main part of a conventional printed wiring board.

[Explanation of symbols]

 10 Multi-Layered Printed Wiring Boards 11-16 First to Sixth Layers 81 Printed Wiring Boards 82 Conductor Patterns 83 IC Mounting Areas 84 Conductor Patterns 85 Foot Patterns 86 Grid-like Patterns 87 First Diagonal Line Patterns 88 Second Diagonal Line Patterns 89 First Weight Reduction Pattern 91 Mounting Hole 92 Conductor Through Hole 93 Printed Wiring Board 94 Conductor Pattern 95 Second Weight Reduction Pattern 97 Hexagonal Weight Reduction Hole 98 Part 99 Conductor Through Hole 100 Printed Wiring Board 101-106th 1st to 6th layers 111 Ground conductor pattern 112 Ground connection conductor through hole 113 Circuit connection pattern 114 Conductor pattern 115 Power supply conductor pattern 116 Ground connection conductor through hole 117 Power connection conductor through hole 121 Ground conductor pattern 123 Contact Connection conductor through hole 124 Power supply connection conductor through hole 125 Circuit connection pattern 126 Ground conductor pattern 127 Ground connection conductor through hole 128 Power supply connection conductor through hole 131 Power supply conductor pattern 132 Ground connection conductor through hole 133 Power supply connection Conductor through hole 135 Grounding conductor pattern 136 Grounding conductor through hole 137 Conductor pattern 138 Circuit connecting conductor pattern 139 Power supply connecting conductor through hole 141 Conductor through hole 145 Weight reduction pattern 146 Weight reduction hole 151 Trapezoidal weight reduction hole 152 Right triangle weight reduction hole 155 Conductor through hole 156 Enlarged pattern 157 Conductor through hole 158 Conductor breakage portion 161 Right triangle weight reduction hole 165 Weight reduction pattern 166 Tortoise shell Conductor pattern 167 Diagonal line pattern 168 Regular triangle weight reduction pattern 171 Weight reduction pattern, conductor pattern 172 Conductor pattern 173 Circular weight reduction hole 174 Conductor through hole 181 Weight reduction pattern 182 Foot pattern 183 Lead wire pattern 184 Conductor pattern 185 Lead wire Pattern 186 Solder resist film 187 Window hole 191 Lower hole 192 Solder resist film 193 Ring portion 195 Cu plating layer 196 Conductor through hole 201 First conductor pattern 202 Second conductor pattern 203 Third conductor pattern 204 Fourth conductor Pattern 211 Widened portion 212 Narrow width portion 213 Weight reduction holes 215, 216, 217 Widened portion 218, 219, 221 Weight reduction hole 222, 223 Portion 224, 225 Weight reduction hole 231 Material substrate 232 Conductor pattern 235 Printed wiring board 236 Reference hole 237, 238 Mounting hole

Claims (8)

[Claims] 1. A printed wiring board, characterized in that a large number of regular weight reducing holes are provided in a conductor pattern having a spread. 2. The printed wiring board according to claim 1, wherein the weight reducing hole has a polygonal shape. 3. The printed wiring board according to claim 2, wherein the weight reducing hole has a hexagonal shape. 4. The printed wiring board according to claim 1, wherein the weight reducing hole is circular. 5. The printed wiring board according to claim 1, wherein the weight reducing holes have a diagonal pattern passing through diagonal lines of a grid pattern. 6. A printed wiring board, characterized in that a weight reducing hole having a shape along the outer shape of the conductor pattern is provided in a wide conductor pattern portion. 7. The print according to claim 1, wherein the layer on which the conductor pattern is formed is a multi-layer, and a weight reducing hole is provided in at least one layer of the conductor pattern. Wiring board. 8. A printed wiring board comprising a first conductor layer and a second conductor layer, each of which is provided with a large number of regular weight-reducing holes in a conductor pattern having a spread, and wherein the first conductor layer is laminated. A printed wiring board, characterized in that the positions of the weight reducing holes of the layer and the second conductor layer are relatively displaced.