JP3213736B2 - Distributed parameter line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed constant line and, more particularly, to a signal line layer and a ground layer formed by folding a flexible printed circuit comprising a signal line layer and a ground layer zigzag at predetermined intervals. , And a distributed constant line formed by folding upside down.

[0002]

2. Description of the Related Art A conventional distributed constant line will be described with reference to FIG. FIG. 4 is a diagram illustrating a conventional example in which a distributed constant line using a flexible printed circuit (FPC) including two layers of a signal line layer and a ground layer is used as a distributed constant filter line. 4A is a surface view, and FIG.
FIG. 4A is a cross-sectional view taken along the line AA, and FIG. 4C is a rear view.

In FIG. 4, reference numeral 1 denotes a signal line layer;
Is a signal line constituting the signal line layer 1. 2 indicates a ground layer. Reference numeral 4 denotes an insulating layer, and the signal line layer 1 and the ground layer 2
Between the signal line 11 and the ground layer 2. The signal line 11 is made of an extremely thin conductive thin film and is formed on the surface of the insulating layer 4 by printing. The ground layer 2 is formed of a conductive thin film formed on the entire back surface of the insulating layer 4. 3 indicates a front cover coat, and 5 indicates a back cover coat. For convenience of explanation, the front cover coat 3 is omitted in FIG. 4A, and the back cover coat 5 is omitted in FIG. 4C.

A signal line layer 1 and a ground layer 2 shown in FIG.
A distributed constant filter line, a distributed constant delay line having a constant characteristic impedance, and other distributed constant transmission lines can be formed using the two-layer FPC. That is, the signal line 11 and the ground layer 2 that constitute the signal line layer 1 face each other with the insulating layer 4 interposed therebetween, and constitute a capacitor that forms a distributed capacitance therebetween. This distributed capacitance is determined by appropriately designing and adjusting the width of the signal line 11 made of a conductive thin film, the length of the signal line 11, the thickness of the insulating layer 4, and the material. The capacitor forming this distributed capacitance can be used as a distributed constant filter line for removing noise, or generally used as a distributed constant transmission line.

By increasing the FPC length, that is, by increasing the electrical length, a distributed constant filter line having good cutoff characteristics or a distributed constant delay line having a constant characteristic impedance can be obtained. That is, the number of the distributed constant filter lines or the distributed constant delay lines is equal to the number of the signal lines 11 between the signal line 11 and the ground layer 2. Here, when it is desired to store a long FPC in a small volume, the FPC shown in FIG. 4 which is composed of two layers of the signal line 11 and the ground layer 2 is folded back in a zigzag manner at regular intervals. I have. FIG. 5 is a diagram showing a cross section of a distributed constant filter line or a distributed constant transmission line formed by folding and folding the FPC shown in FIG. 4 at a predetermined length in a zigzag manner.

[0006]

By the way, the signal line layer 1
By simply folding and folding the two-layer FPC including the ground layer 2 and the same layer, the same signal line layers 1 face each other with the front cover coat layer 3 interposed therebetween, and the continuous signal lines 11 facing each other. Communicators are electrostatically coupled to generate stray capacitance. This will be described with reference to FIG. 5. When attention is paid to a portion indicated by C which descends from the peak to the valley by folding the FPC in a zigzag and a portion indicated by D which rises from the valley to the mountain, the two portions are continuous. Signal line 11
The competitors face each other with two layers of the surface cover coat layer 3 interposed therebetween. When the continuous signal lines 11 face each other as described above, they are electrostatically coupled to each other to generate a stray capacitance. The distribution capacitance between the signal line 11 and the ground layer 2 is
As described above, the design can be adjusted by paying attention to the width of the signal line 11 made of the conductive thin film, the length of the signal line 11, the thickness and the material of the insulating layer 4, but a stray capacitance occurs between the signal lines 11. In this case, since the stray capacitance is indefinite, the distributed capacitance cannot be obtained as designed because of the inconvenience, and the required electric length or characteristic impedance cannot be obtained.

According to the present invention, a flexible printed circuit comprising two layers, a signal line layer and a ground layer, is folded in a zigzag manner at predetermined intervals, and the signal line layer and the ground layer are turned upside down and folded. It is an object of the present invention to provide a distributed constant line which solves the following problems.

[0008]

A flexible printed circuit composed of two layers, a signal line layer 1 on which a signal line 11 is formed and a ground layer 2 is folded back in a zigzag manner at predetermined lengths.
And the ground layer 2 were turned upside down to form a distributed transmission line in a convoluted configuration. The flexible printed circuit constituted a distributed constant transmission line in which the signal line layer 1 and the ground layer 2 were formed on both front and back surfaces of the insulating layer 6.

The signal line layer 1 and the ground layer 2 are alternately formed on the front and back surfaces of the insulating layer 6 at regular intervals, and the adjacent signal lines 11 are electrically connected to each other. A distributed constant transmission line electrically connecting the ground layers 2a and 2b on the front and back sides adjacent to each other was formed. Here, a flexible printed circuit composed of two layers of the signal line layer 1 and the ground layer 2 on which the signal line 11 is formed is folded back in a zigzag manner at regular intervals, and the signal line layer 1 and the ground layer 2 are turned upside down. A distributed constant filter line characterized by being convoluted is constructed.

The flexible printed circuit has a distributed constant filter line in which a signal line layer 1 and a ground layer 2 are formed on both sides of an insulating layer. Also, the signal line layer 1
And the ground layer 2 are alternately formed on the front and back surfaces of the insulating layer 6 at regular intervals, to electrically connect the adjacent front and back signal lines 11 and to connect the front and back ground layers 2a adjacent to each other. , 2b are connected to each other to form a distributed constant filter line.

Further, a flexible printed circuit comprising two layers of the signal line layer 1 and the ground layer 2 on which the signal lines 11 are formed is zigzagged at a predetermined length so that the signal line layer 1 and the ground layer 2 are turned upside down. The distributed constant delay line was constructed by inversion and convolution. The flexible printed circuit constituted a distributed constant delay line in which a signal line layer 1 and a ground layer 2 were formed on both sides of an insulating layer.

The signal line layer 1 and the ground layer 2 are alternately formed on the front and back surfaces of the insulating layer at regular intervals, and the adjacent signal lines 11 on the front and back are electrically connected and mutually connected. A distributed constant delay line electrically connecting the front and back ground layers 2a and 2b adjacent to each other is formed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram for explaining an embodiment in which a distributed constant line using an FPC composed of two layers of a signal line layer and a ground layer is used as a distributed constant filter line.
1A is a front view, FIG. 1B is a view showing a cross section taken along line AA of FIG. 1A, and FIG. 1C is a rear view. FIG.
FIG. 2 is a diagram showing a cross section of a line formed by folding and folding the FPC shown in FIG. 1. FIG. 3 is a perspective view showing a state where the line shown in FIG. 2 is mounted on a substrate.

In FIG. 1, reference numeral 1a denotes a front signal line layer, and 1b denotes a rear signal line layer. Reference numeral 20 denotes a through hole through which the signal line 11 constituting the signal line layer 1 passes. 2
a indicates a front ground layer, and 2b indicates a rear ground layer. Reference numeral 40 denotes a through hole through which a connection conductor for electrically connecting the front ground layer 2a and the rear ground layer 2b is penetrated. 5 indicates a front cover coat, and 7 indicates a back cover coat. Reference numeral 6 denotes an insulating layer. For convenience of explanation, FIG. 1A omits the surface cover coat 5 and FIG.
(C) omits the back cover coat 7.

In this embodiment, as in the prior art, the signal line 11 and the ground layer 2 constituting the signal line layer 1 face each other with the insulating layer 6 interposed therebetween, and a capacitor for forming a distributed capacitance therebetween is provided. Make up. The distributed capacitance is determined by appropriately designing and adjusting the width of the signal line 11 made of a conductive thin film, the length of the signal line 11, the thickness of the insulating layer 6, and the material. In the design adjustment of the width of the signal line 11 forming the signal line layer, a design adjustment for periodically changing the width is also performed.
A capacitor forming this distributed capacitance can be used as a distributed constant filter line for removing noise, or generally used as a distributed constant transmission line.

Here, in FIG. 1, when the FPC is given a reference symbol A to H at the folded portion, the back portion B
Is connected to the signal line layer 1a on the front surface portion C via the through hole 20, and the signal line layer 1a on the front surface portion C is connected to the rear surface portion D via the through hole 20.
And the signal line layer 1b in the portion D on the rear surface is further connected to the signal line layer 1a in the portion E on the front surface via the through hole 20, and so on. The ground layer 2a on the front surface and the ground layer 2b on the back surface are indicated by oblique lines. The front ground layer 2a and the rear ground layer 2b are electrically connected via a connection lead penetrating through hole 40.

FIG. 1 shows a one-dot chain line and a two-dot chain line. The one-dot chain line indicates that the turning point is mountain-folded, and the two-dot chain line indicates that the turning point is trough-folded. ing. When the FPC shown in FIG. 1 is folded back in a zigzag manner as shown by a chain line, a distributed constant filter line or a distributed constant delay line as shown by a cross section in FIG. 2 is formed. That is, the portions A to H shown in FIG. 1 correspond to those shown in FIG.

Referring to FIG. 2, when attention is paid to a portion C which descends from a peak to a valley and a portion D which rises from a valley to a valley by turning the FPC zigzag, the signal lines 11 continuous in both portions are opposed to each other. However, the surface cover coat layer 5 of the portion C, the surface cover coat layer 5 of the portion D, the surface ground layer 2a of the portion D, and the insulating layer 6 are interposed between the opposing signal lines 11. Here, focusing on the interposition of the surface ground layer 2a of the portion D between the continuous signal lines 11 of both opposing portions, these signal lines 1
The ones are shielded from each other by the ground layer 2a and do not face each other directly, eliminating the electrostatic coupling between the signal lines. The above is the part E where the continuous signal lines 11 descend from the opposing mountain to the valley and the part F where the continuous signal lines 11 rise from the valley to the mountain
Holds similarly.

As described above, the distributed constant line according to the present invention comprises:
A flexible printed circuit composed of two layers, a signal line layer and a ground layer, is folded in a zigzag manner at a predetermined length, and the signal line layer and the ground layer are turned upside down to form a folded structure. The signal lines forming the layers are shielded by the ground layer, so that the signal lines do not directly face each other, and there is no stray capacitance due to the loss of electrostatic coupling between the signal lines. Therefore, the distribution capacitance between the signal line and the ground layer cannot be as designed, due to the indeterminate stray capacitance as a result of this electrostatic coupling, and the electrical length is compared with the designed electrical length. However, the disadvantage of shifting to a shorter one is eliminated, and a distributed constant filter line, a distributed constant delay line, and generally a distributed constant line having a required design electrical length or characteristic impedance can be easily obtained.

[0020]

As described above, according to the present invention, a flexible printed circuit composed of two layers, a signal line layer and a ground layer, is folded in a zigzag manner at regular intervals to form a signal line layer and a ground line. By turning the ground layer upside down and folding it up to shield the opposing signal lines with the ground layer, a distributed constant line that can be accommodated in a small volume with a long electrical length can be configured as designed. .

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a distributed constant line,
1 (a) is a surface view, and FIG. 1 (b) is AA in FIG. 1 (a).
The figure which shows the cross section along the line, FIG.1 (c) is a rear view.

FIG. 2 is a diagram showing a cross section of the line shown in FIG. 1;

FIG. 3 is a perspective view of the line shown in FIG. 2;

FIG. 4 is a diagram illustrating a conventional example of a distributed constant line;
4 (a) is a surface view, and FIG. 4 (b) is AA in FIG. 4 (a).
FIG. 4C is a diagram showing a cross section along a line, and FIG.

FIG. 5 is a diagram showing a cross section of the distributed constant line shown in FIG. 4;

[Description of Signs] 1 signal line layer 11 signal line 2 ground layer 2a front ground layer 2b back ground layer 6 insulating layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-155805 (JP, A) JP-A-7-245575 (JP, A) JP-A-59-1441619 (JP, U) JP-A-2- 143802 (JP, U) Fully open 1987-6-5417 (JP, U) Fully open 1983-116262 (JP, U) Fully open 1987-145400 (JP, U) Fully open 1979-90685 (JP, U) Special Table Hei 6-502956 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01P 3/02 H01P 9/00

Claims (3)

(57) [Claims] The signal line layer and the ground layer are on the front and back of the insulating layer.
Tables that are alternately formed on both sides at regular intervals and that are adjacent to each other
The signal lines on the back are electrically connected, and the front and back sides are adjacent to each other
Flexible prints where the ground layers are electrically connected
The circuit is folded back zigzag at the fixed length
Make sure that the wire layer and ground layer are
And a distributed transmission line characterized by the following. 2. The method according to claim 1, wherein the signal line layer and the ground layer are on both sides of the insulating layer.
Tables that are alternately formed on both sides at regular intervals and that are adjacent to each other
The signal lines on the back are electrically connected, and the front and back sides are adjacent to each other
Flexible prints where the ground layers are electrically connected
The circuit is folded back zigzag at the fixed length
Make sure that the wire layer and ground layer are
And a distributed constant filter line characterized by the following. 3. The signal line layer and the ground layer are on the front and back of the insulating layer.
Tables that are alternately formed on both sides at regular intervals and that are adjacent to each other
The signal lines on the back are electrically connected, and the front and back sides are adjacent to each other
Flexible prints where the ground layers are electrically connected
The circuit is folded back zigzag at the fixed length
Make sure that the wire layer and ground layer are
And a distributed delay line characterized by the following.